T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y
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Vol. 9, No.
I
ORIGINAL PAPERS THE MAMJFACTURE OF LINOLEUM: AND ITS VALUATION
due t o t h e cork present is seen in t h e followiqg unsaponifiable organic matter insoluble in acetone:
BY ARMANDDE WAELB Received August 26, 1916
.
T h e literature on t h e subject of t h e valuation of floor coverings embodied under t h e various descriptions of floor-cloth, linoleum a n d cork carpet is somewhat scant a n d , a p a r t from a paper on t h e subject b y Ingle’ i n which t h e author submits a limited amount of chemical d a t a , for t h e most p a r t t h e testing of these products is limited t o crude rule of t h u m b methods. As Ingle points o u t , a n exception is t o be found in a publication of Burchartz2 who gives t h e tests of t h e German Government. Most of t h e English Government tests are physical, embodying determinations of specific gravity, water absorption a n d i n rare cases a bending test, i. e., t h e manufacturers have t o tender a sample which will bend over mandrils of s t a t e d diameters without breaking. More recently certain of t h e governmental departments have specified compliance of goods submitted with certain chemical tests, principal among which are moisture a n d ash content together with t w o determinations, t h e value of which are questioned b y t h e writer for reasons s t a t e d below, viz: “Acetone extract,” a n d “Unsaponifiable matter insoluble i n acetone.” T h e l a t t e r test in t h e writer’s opinion is a n a t t e m p t t o obtain a n idea of t h e cork content of t h e material. Attrition or wearing tests have from time t o time been suggested, a n d various methods adopted with a view t o obtaining a comparative measure of t h e wearing power of linoleums. Experience, however, has shown t h a t none of these tests give results which are in a n y way trustworthy. T h e determination of t h e ether extract as suggested b y Pinette3 is very misleading, for as Ingle points out in his paper referred t o above, no judgment can be made unless t h e constituents of t h e linoleum are known both qualitatively a n d quantitatively. With regard t o t h e government tests of ‘(Acetone extract” a n d “Unsaponifiable matter insoluble i n acetone,” t h e later remarks as t o t h e indefinite a m o u n t of soluble m a t t e r extracted b y ether from oxidized oils apply even more forcibly i n t h e case of acetone extracting, especially as no stipulations are made as t o t h e subdivision of t h e sample, a n d no period of exhaustion is specified. I n t h e case of “unsaponifiable matter” i t h a d been remarked in Ingle’s paper previously referred t o b y s. Stewart (discussion) t h a t this q u a n t i t y was very variable a n d depended on t h e conditions under which saponification was effected. T h u s saponification of cork b y alcoholic potash in a n open basin yielded 33 t o 36 per cent unsaponifiable matter while saponification under a reflux condenser yielded about 7 2 per cent. I n t h e case of a plain linoleum examined for a government tender, a great divergence 1
J . SOL.Chem. Ind., 23 (1904), 119i-1201.
:Ibrd., 19 (1900), 2 5 5 . Ibid., 1892, 5 5 0 .
SAPONIFICATION UNDER REFLUX
Per cent unsaponifiable
I With 8 per cent. alcoholic soda.. . . . . . . . . . . . 11 With 0 . 2 5 per cent. aqueous soda.
. . . .. ... ,
11.11 16.47
The unsaponifiable m a t t e r i n each case was dried, weighed, extracted with acetone, weighed, a n d t h e organic matter therein determined b y incineration. I t may be mentioned t h a t constancy is obtained b y t h e 0 . 2 5 per cent aqueous soda saponification of cork, t h e unsaponifiable matter t h u s obtained X 1.43 giving a fair approximation t o t h e cork present. MANUFACTURE O F L I N O L E U X
T h e name “linoleum” defines a product of fairly characteristic composition, a n d represents practically t h e same product as t h a t patented in 1864 b y Frederick Walton, who may justly be deemed t h e father of t h e linoleum industry. T h e adoption of t h e processes employed appears t o have been arrived a t b y a method of evolution, little chemical knowledge seeming t o be possessed on t h e n a t u r e of t h e reactions involved or justification for t h e choice of materials; nevertheless i t stands highly t o t h e credit of t h e original inventor t h a t t h e attention of chemists a n d technologists has hitherto not succeeded i n effecting any change from t h e process as originally conceived b y him half a century ago. Floorcloth, so-called “floor oil cloth,” is a material quite distinct from linoleum, consisting as i t does of a strong, coarse, j u t e canvas t o which a variable number of coats of a coarse, low-grade paint have been applied on either side, a finishing application of a printed paint design followed b y a light coating of varnish being applied t o t h e wearing surface. T h e manufacture of floorcloth a t t h e present d a y is comparatively unimp o r t a n t , as i t possesses none of those qualities of resiliency a n d nonconductivity t o heat which mark linoleum. It is, therefore, not my intention t o include its discussion i n t h e present paper. T h e Taylor-Parnacott or Corticine floor coverings are, strictly speaking, not coterminous with t r u e linoleums, as t h e method of manufacture of t h e solidified oil necessary for their production differs from t h e linoleum process in being mainly a polymerization process as distinct from t h e oxidation t r e a t ment used in t r u e linoleum. This class of floor covering, however, differs f r o m floorcloths a n d resembles linoleums in t h a t its manufacture consists in t h e application of a previously prepared composition containing solidified oil t o canvas, instead of allowing t h e oil t o solidify in combination with filler actually on t h e canvas support as in t h e case of floorcloth. T h e main difference, however, between linoleums a n d “corticines” from t h e manufacturers’ standpoint is t h a t , considered a t t h e particular stage of t h e process where t h e solidified oil is directly mixed with cork a n d pigment t o make t h e linoleum material, t h e cohesive properties of “corticine” oil are too poor t o allow of
Jan., 1917
T H E J O U R N A L OF I N D U S T R I A L A N D ENGIlVEERING C H E M I S T k Y
its employment for those products which demand t h e use of a n oil of high binding power such as is used for inlaid linoleums. T h u s oil prepared b y the TaylorParnacott or corticine process is used only for t h e manufacture of uni-colored or plain cloths a n d for “cork carpets,” these l a t t e r products merely consisting of a n oil-cork-pigment mixture in which t h e cork employed is of a coarse variety, t h u s ensuring t h e maximum of resiliency a n d w a r m t h to t h e feet. MANUFACTURE O F CORTICINE PRODCCTS
T h e manufacture of t h e oil-binding medium involves a partial solidification b y a process of combined oxidation a n d polymerization a t a high temperature. T h e object aimed a t i n t h e several processes is t o obtain a product resembling a n unvulcanized india rubber of maximum “covering power” or power t o t a k e u p filler, this rubber-like product being capable of undergoing subsequently a f u r t h e r change in order t o obtain a product of increased solidity resembling leather. I t t h u s becomes a t once apparent why t h e d r y i n g o i l s are universally chosen as t h e basis for t h e binder. Linseed oil possesses t h e property of finally yielding a dry elastic body (the main constituent of which is Mulder’s “linoxyn,” vide i n f r a ) a n d a t t h e same time by special t r e a t m e n t can be caused t o appear in a n intermediate stage as a body possessing t h e optimum of tackiness. I n manufacturing t h e Taylor-Parnacott or “corticine” product a q u a n t i t y representing a b o u t z1/2 tons of (preferably) t a n k e d Baltic linseed oil is heated t o a temperature in t h e neighborhood of 2 2 0 ’ C. in a large open iron pan. Driers consisting of a mixture of a b o u t 2 per cent of flake litharge a n d I per cent of crystallized lead acetate are t h e n dusted in. T h e latter drier has t h e effect of partly redissolving a n y metallic lead formed b y reduction of t h e litharge b y t h e h o t oil a n d t h e water of crystallization of t h e salt has possibly some obscure action i n distilling off volatile products’ formed b y t h e saponification of t h e oil b y the basic lead drier. A certain a m o u n t of mucilage or foots will have separated o u t a t this temperature together with some spongy lead. T h e hot oil is t h e n blown for 2 or 3 hours, t h e fire being previously withdrawn. T h e object of t h e blowing is many fold: it ensures a thorough agitation of t h e oil a n d supplies t h e best conditions for t h e solution of t h e driers; i t also gives a n initial s t a r t t o t h e oxidation a n d t h u s facilitates subsequent polymerization; furthermore, i t is t h e means of reoxidizing a n y metallic lead in t h e spongy condition a n d i t has probably also t h e effect of oxidizing away t h e separated mucilage. This oil is allowed t o cool 1 2 hrs. a n d is t h e n transferred t o pots (‘/?-ton capacity), fixed i n a brickwork setting a n d heated b y direct fire, t h e coal being contained in a grate on wheels in such manner as t o permit instant withdrawal of t h e source of heat when necessary. The contents of these smaller pans are then raised t o a temperature in t h e neighborhood of 1 I purposely refrain from stating that these volatile products consist of either acrolein or glycerin in spite of the general assurance of many
writers t h a t such is the case, as i t is obvious t h a t the equation involved does not bear such statement out.
7
250’ C. a n d maintained thus, receiving occasional stirring b y hand. I n something like 8 to 1 2 hours, thick skins form on t h e surface of t h e hot oil which has gradually increased in viscosity. F r o m this point vigorous agitation of t h e oil is resorted t o until solid rubber-like nuclei make their appearance. At a point judged b y t h e oil boiler, stirring is stopped a n d t h e fire withdrawn. Solidification takes place gradually throughout t h e mass, t h e top surface of t h e oil being quite dry a n d leathery, a n d small vents form, through which acrid vapors escape. T h e partly entrapped gaseous products within t h e mass t h e n expand t h e contents of t h e p o t , t h e rising of t h e “head” necessitating t h e placing of short tubes or rings of t h e same diameter as t h e p a n on t h e upper edge t o prevent overflowing. T h e t r e a t m e n t of t h e oil is t h e n concluded a n d after t h e rising is finished t h e mass contracts somewhat. T h e contents of t h e pot are t h e n allowed t o cool for 2 or 3 days, t h e n cut into segments in situ a n d finally floated out b y water. This solidified oil presents t h e honeycombed a p pearance of a loaf of bread except t h a t t h e bottom a n d those parts immediately adjacent t o t h e sides are somewhat greasy, T h e actual t r e a t m e n t of t h e oil being concluded, t h e remainder of t h e process necessary t o manufacture “Taylor cloth” or “cork carpet” consists cf t h e mixing together of t h e oil with fine or coarse cork and t h e necessary pigment a n d a final rolling on t o a canvas backing. T h e so-obtained “raw” or LLgreen”cloth is t h e n hung for several weeks in bights i n a “stove” or large steam-coil heated room maintained at 1 2 0 t o 160’ F.in order t o convert i t from t h e plastic t o the leathery or finished condition. This subsequent t r e a t m e n t of “cloth” is t h e same whatever oil basis is used, SO far as the manufacture in a plastic s t a t e followed by t h e stoving is concerned, a n d it is t h e aim of t h e manufacturer t o obtain t h e maximum binding or cohesive property of his product a t this intermediate stage together with t h e highest degree of leatheriness a f t e r stoving. I t is somewhat difficult t o describe t h e physical properties of t h e products which constitute what is regarded in t h e t r a d e as a good cloth, b u t t h e subsequent descriptions of t h e methods I have employed in t h e valuation of linoleums may give t h e reader t h e clue t o this conception. It is here necessary t o mention t h a t “cork carpets” or cloths of high resiliency made with coarse corks s t a n d b y themselves as a class of floor covering made entirely by t h e process just described. The reason f o r this is t h a t t h e oil basis used for t r u e linoleum i n variably contains a certain proportion of resins which would not only detract from t h e high resiliency for which cork carpet is noted b u t would for mechanical reasons prevent t h e sand-papering of t h e rough face of a cork carpet, there being a fair demand in t h e trade for such “buffed” goods. A “Taylor cloth,” however, represents t h e other class of floor covering made with this polymerized oil a n d merely consists of a similar admixture with fine instead of coarse cork. Apart from t h e reason t h a t it is t h e staple product of t h e few manufacturers who do not possess t h e con-
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T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING CHEiMISTRY
siderably more expensive “linoleum cement” plant, there exists a certain demand for i t b y some governmental departments. It possesses nothing b u t disadvantages over linoleum a n d is more expensive t o make.
Vol. 9, No.
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temperature necessary, usually g o o F. A large pipe fitted with a rotary p u m p connects t h e lower level t o t h e t o p t a n k b y which means t h e oil descends i n a continual rain t o t h e lower t a n k . A f a n is fitted t o t h e body of t h e box t o replenish t h e air a n d remove acrid THE W A L T O N “ C E M E N T ” vapors. As a rule a Io-ton lot of oil will h a v e attained such a T h e other, a n d b y far t h e more important process for t h e manufacture of a solidified oil basis, is t h e viscosity i n 7 2 hours t h a t it will no longer flow through invention of Frederick Walton in 1864. T h e prep- t h e openings i n t h e roof; t h e n t h e thickened oil is aration of this oil basis which will hereinafter be admixed with about 5 per cent of whiting a n d transferred in t o n lots t o short, horizontal jacketed drums referred t o under i t s technical name of “cement” involves t w o distinct treatments. T h e raw linseed fitted with a horizontal shaft with radial arms. Steam oil is first of all converted into a solid oxidized product is first of all admitted t o raise t h e oil t o about 120’ F. of moderate greasiness, low elasticity a n d binding b u t subsequently, as oxidation proceeds rapidly, i t is power; this product is t h e n transformed b y a heating necessary t o admit cold water t o t h e jacket t o keep t h e process, consisting probably of a n intramolecular temperature under control. T h e object of this rearrangement, into a body which has lost t h e greater “smacker,” as i t is called, is t o perform a n oxidation p a r t of its greasiness a n d possesses a n elasticity a n d t h a t i t is beyond t h e power of t h e shower b a t h t o binding power of very high degree. Although there continue, while t h e latter apparatus is employed o n are no less t h a n three distinct processes for solidifying account of its high efficiency a n d t h e low power ret h e oil b y oxidation, t h e second t r e a t m e n t referred t o quired. A powerful draft of air is admitted into t h e ( t h e conversion of t h e oxidized oil into “cement”) is smacker during i t s operation. T h e “smacking” t r e a t m e n t is continued until a t h e same in every case. Of t h e three oxidation processes now in use, t w o sample withdrawn will just barely flow, a point usually are t h e invention of Frederick Walton. T h e third, arrived a t in about 48 hrs. A treacle valve is t h e n or Wood-Bedford process, in spite of its being t h e sub- opened i n t h e b o t t o m of t h e vessel a n d t h e nearly solid ject of a more recent invention (being a derivation of oil received onto a layer of whiting i n a room im6ne of t h e former processes a n d yielding a very con- mediately underneath. T h e oil solidifies on attainsiderably inferior product), is adaptable only t o t h e ing room temperature t o a mass of t h e consistency of lower qualities of plain cloths a n d impossible of applica- liver, when i t is cut i n t o slabs, transferred t o trays a n d tion for inlaid linoleums which necessitate high cohesive kept i n stoves a t 100’ F. for several days, when t h e qualities when i n t h e intermediate or plastic stage. action of t h e evolved acid products on t h e contained T h e Wood-Bedford process, i t may be mentioned, is whiting causes t h e mass t o rise somewhat a n d develop a n internally honeycombed structure. An increase i n very little used. T h e first of t h e Walton processes for t h e oxidation body, possibly due t o further oxidation facilitated b y of linseed oil is t h e “scrim” process, so-called for t h e t h e greater surface exposed, is t h e result of this stoving. reason t h a t light cotton fabrics or “scrims” are suc- T h e oil t h u s prepared is t h e n ready for conversion i n t o cessively flooded with a n oil boiled with suitable driers, cement i n precisely t h e same way as in t h e case of oil each layer being allowed t o d r y before being followed prepared as previously described. I t has been observed as a general rule t h a t slow b y t h e next flooding. T h e scrims are i n widths of 3 ft. a n d 20 ft. in length a n d are suspended vertically oxidation yields a more favorable product t h a n one i n a tall building, capable of accommodating 1000 t o t h a t is obtained b y rapid methods; hence i t is advantageous from this point of view t o prolong as much 2000 a n d maintained at a temperature of 80 t o 90 O F. T h e drainings from t h e scrims a r e returned for a as possible t h e shower b a t h treatment a t t h e expense further flooding, being replenished with fresh oil when of t h e smacker t r e a t m e n t . T h e Wood-Bedford process consists merely i n t h e necessary. According t o t h e nature a n d a m o u n t of t h e driers used either one or t w o floodings are per- performance of t h e oxidation throughout i n t h e formed every 2 4 hrs. T h e skin formed will a t t a i n as smacker, temperatures u p t o 140’ F. being obtained. a rule a thickness of about one inch in 4 mos., when its T h e whole oxidation can be completed i n 48 hours, b u t excessive weight renders i t liable t o fall a n d flooding as a consequence of t h e rapidity of reaction a vastly is stopped. A final drying off is t h e n given a n d t h e inferior product is obtained, suitable for t h i n qualities skins c u t down. T h e y are t h e n ready for conversion only. It may be mentioned a t this point t h a t thickness of i n t o cement. I n t h e second Walton process, commonly known as “cloth” obtained a n d “quality” are practically t h e “shower b a t h ” process, t h e raw oil is admixed synonymous terms, t h e several degrees of t h e higher i n t h e cold with a very small percentage of insoluble qualities being usually made with similar ingredients drier, a n d subjected t o a preliminary oxidation i n a while for t h e lower grades or thicknesses of cloth t h e large “shower b a t h ” which consists of a n enclosed high s t a n d a r d of ingredients employed need not be rectangular box about 18 ft. high, having its roof adhered t o . T h e next stage of t h e process is t h a t of t h e further perforated with a number of holes, t h e upper extension forming a shallow open t a n k . T h e lower portion of t r e a t m e n t of t h e oil t h a t has been oxidized b y t h e t h e box contains steam coils t o heat t h e oil t o t h e ‘(scrim,” “shower b a t h ” or Wood-Bedford processes.
J a n . , 1917
T IiT E J 0 U R ATA L 0F I N D U S T RI A L A N D E N G I N E E RI NG C H E M I S T R Y
T h e original a n d yet up-to-date process as originally patented b y F. Walton is as follom-s: 1 5 t o 17 cwt. of oxidized oil are p u t into a large pan fitted with a s t e a m jacket and agitators. T h e pressure of s t e a m is such t h a t temperatures of 130 t o 150’ C. are easily obtained. A quantity of molten rosin in t h e proportion of I : 8 of t h e oil is t h e n poured on, followed b y a similar quantity of powdered g u m kauri. Agitation is continued a t a slow speed until t h e oxidized oil runs down t o a thick fluid, a considerable evolution of water, formic acid, etc., taking place. After t h e melting of t h e oil, when t h e mass rises u p , t h e speed of the stirrers is increased t o cause it t o return. F r o m t h e Point a t which t h e “turning” or diminishing of t h e head takes place, thickening of t h e mixture occurs with more or less rapidity. A t t h e same time t h e Oil changes f r o m its characteristic butter-yellow t o a reddish brown, this darkening being independent of t h e influence Of the rather dark gum At a point judged b y t h e operator, t h e “cement,’ as i t is termed, is tipped out of t h e pan either b y overturning on its swivel or in other forms of plant b y opening a sluice valve a t t h e bottom. As t h e hot mass does not cool rapidly, means are adopted t o reduce t h e continuation of t h e cooking action after leaving t h e cement pan. This is accomplished either b y running the hot cement o u t onto a concrete floor mounded u p t o (2 low cone or tipping directly onto revolving water-cooled rolls. T h e “cement,” after cooling, is t h e n cut u p into slabs, a n d left t o “hang” or mature for a week or t w o t o increase its body:
9
volatile bodies of low molecular weight, among which I have identified bodies with aldehydic groupings, formic acid, etc. It is probable also t h a t decomposition of t h e peroxides takes place in a somewhat similar manner under hydrolysis b y alkali, i. e., t h a t disrupture of t h e chain a t t h e position originally occupied b y t h e double bond may occur, t h u s yielding smaller molecules, -CHO -COOH I 1 HzO + -CHO -CH20H an oxidized linseed oil by saponification yielding considerable quantities of soluble (lower) f a t t y acids, together with the invariable tcoxidized,, which in my opinion consist of the nine-carbon radicle terminated b y a n aldehydic group a t one or both ends resinifying. The actual proof of such action occurring as suggested by Ingle is somewhat difficult b u t I offer t h e following as a proof negating t h e suggestion of polymerization^ Determinations of the content of solid f a t t y acids on a n oil during t h e process t o oxidation till solid and then subsequently after its treatment b y heat a t 150’ C. in t h e cementing process have invariably shown t h e percentage of t h e same t o remain constant. An oil polymerized till solid a t 2 5 0 ’ C. in an atmosphere of carbonic acid showed a n increase in acids behaving as solid or saturated acids2 of from 5 . 2 j t o 48.8 per cent. T h e acids isolated possessed properties different from true saturated acids in t h a t they were viscous, g u m m y solids, instead of being hard REACTI0N S and crystalline, and furthermore showed a n iodine We have t h u s in t h e linoleum process two definite value of 86 instead of in the neighborhood of zero. reactions, t h e first being a simple oxidation a n d t h e T h e 48.8 per cent obtained would include (unless second a process for which I suggest destruction of t h e 5 . 2 5 per cent of t r u e saturated acids Of either a molecular rearrangement Of group- be presumed7 t h e original saturated acids present, a n d ings or a condensation, or even possibly a combination t h e difference of 4 3 . j per cent I have assumed to be of t h e two. At first sight t h e reaction occurring in t h e true polymerized acids. I may mention that various cement pan suggest as a polymerization. trials have so far convinced me as to t h e infallibility A polymerization would include a linking together of of this test for determining polymerization, that I bonds together an increase Of molecular have constantly used i t for recognizing this t r e a t m e n t . weight. Ingle‘ suggests t h a t t h e reaction occurring Further elucidation of t h e cement pan reaction has is one of rupture in t h e chain in t h e middle of a peroxide as yet yielded no definite results. Measurement of group, such group being in t h e position of t h e original t h e possible increase in t h e number of molecules by double linkage, t h u s : subdivision of t h e original chain, as determined b y CHa.CH2.CH:CH.(CHz)4CH: CH.(CH2)6CH:CH.COO.gzy increased saponification values yielded, as 1 had t o CHs.CHz.CH.CH(CHz)aCH.CH.(CHz)sCH.CH.COO.gly anticipated, no d a t a , since as suggested above, hyI I ! I I 1 0-0 0-0 0-0 drolysis of t h e uncooked solid oil would similarly affect This would be transformed more or less completely in the breaking down a t t h e double bond positions. t h e cement process t o Working on t h e evidence at my disposal afforded b y the possibility of resolving linoleum into extractable CH~.CH~.CHO.CHO.(CHZ)~.CHO.CHO. (CHz)s.CHO.CHO.COO.gly. residual fractions, I have performed experiments T h e above equations have been shown for t h e sake of throughout during t h e course of transformation from convenience as occurring on a monobasic radicle,-gly. raw oil t o t h e oxidized, “cemented”. and matured Although t h e above equations as submitted b y product in order t o determine t h e changes occurring Ingle for linolenin do not coincide as regards t h e therein. EXPERIMENTAL position of t h e double bonds t o the structure generally accorded t o this body, t h e mechanism of t h e deSome experiments performed as a side issue have composition of t h e peroxides is probably depicted cor- shown me t h a t my obvious surmise t h a t t h e subserectly. We have evidence for this in t h e evolution of lFahrion,
+
+
1
J . SOC.Chem. I n d . , 1918, 640.
2
Fachini-Dorta Acetone Method.
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T H E J O U R N A L OF I N D U S T R I A L A N D EJGINEERI-VG C H E M I S T R Y
quent changes taking place on oxidized oils after their solidification b y oxidation whether b y t h e “scrim,” “shower b a t h ” or Wood a n d Bedford process are of t h e same order, has proved t o be correct, a n d I need not detail t h e d a t a t h a t have led u p t o this assumption. For reasons of expediency, however, m y work has been mostly done on t h e oxidized oil obtained b y t h e “scrim” process, as t h e solid oils obtained t h u s have lower extracts as a general rule, or in other words are drier, a n d consequently facilitate extraction. T h u s t h e skins obtained b y t h e scrini process can be r u n into very thin sheets b y passing through cold rolls and extract figures can be obtained which represent sufficiently accurate values for our purposes, b y 2 4 hours continuous exhaustion. I t will be noted t h a t I make a reservation in t h e foregoing statement as t o t h e absolute value of t h e figures obtained for extracts, t h e qualification therefor being as follows: T h e “skin” obtained b y t h e “scrim” or natural oxidation process presents an appearance a n d physical properties somewhat resembling a piece of bichromated glue jelly. I t is somewhat harder, if anything, opaque brown t o transparent yellow, according t o t h e n a t u r e of t h e driers used, a n d i n thicknesses of about a n inch usually breaks when bent double t h u s showing its limited elasticity. When sheeted through cold rolls it is opaque light yellow. I n this l a t t e r form t h e maximum surface can be obtained for extraction for a given weight A Io-gram lot of sheeted skins was transferred t o a n extraction thimble formed b y cutting off t h e lower end of an ordinary 6 in. X I in. boiling t u b e a n d tying a piece of linen over t h e t o p lip. This was t h a n p u t , linen end downwards, into a n ordinary Soxhlet extractor. T h e apparatus, fitted u p i n t h e usual manner, was transferred t o a water b a t h , a n d t h e skin extracted with ordinary ether of 0 . 7 2 0 sp. gr. At t h e end of 2 4 hrs. t h e ether was driven off from t h e extraction flask, C o n being used t o drive off t h e final traces. T h e extract obtained amounted t o 67.5 per cent. A further extraction of 2 4 , 48 a n d 7 2 hrs. was t h e n done in order t o determine whether t h e exhaustion was complete. As a consequence of t h e results obtained, extraction was continued for a period u p t o 4 l / 2 mos. T h e figures obtained for t h e whole period of extraction are as follows:
Val. 9 , No.
I
soluble acting as a “latent” solvent t o t h e other. I n t h e first suggestion it is necessary t o assume t h a t t h e high initial extract represents some t r u e soluble matter whereas t h e succeeding small extracts consist of t h e transformed insoluble body. This particular phenomenon is emphasized as being of importance in showing analogy with subsequently described reactions. Similar results were obtained with alcohol, benzene, chloroform a n d acetone. Petroleum ether of B. P. 3 5 t o joo C., however, while still showing no definite end-point of extractable matter, gave a n extract which i n q u a n t i t y and appearance differed so far from t h a t obtained b y t h e other solvents as t o warrant further investigation. During t h e course of t h e routine examination of samples of skins for extractable m a t t e r , t h e fusibility of t h e skins for purposes of conversion into cement being roughly proportioned t o t h e ether extract, i t was often observed t h a t skins of similar extract gave very different results in practice. T h u s i t would often happen t h a t t w o apparently different skins of which one would be adjudged b y t h e rule of t h u m b and fairly accurate test t o be superior to t h e other, while yielding t h e s a m e q u a n t i t y , gave extracts differing in physical a n d chemical properties. T h u s t h e extract would be more or less viscous, a n d would differ in color, while t h e acid value a n d yield of “oxidized acids” obtained on saponification would be dissimilar. T h e result of a very long series of test experiments has finally shown me t h a t t h e t o t a l extract can be resolved into t w o or even more fractions, for practical purposes being limited in utility t o two: ( I ) t h e e s t r a c t obtained b y 2 4 hours extraction with lo^ boiling point petroleum ether, a n d (2) t h e extract obtained b y a further extraction of t h e residue with ordinary ether. Very striking is a comparison of t h e physical properties of these t w o fractions. T h e petroleum ether extract consists of a pale greenish yellow, fairly mobile oil, a turbidity being apparent in it due t o white crystals which settle out on standing: exposure t o air for very long periods shows i t t o possess no power t o dry t o a hard skin, a certain amount of thickening however taking place. T h e subsequent ether extract is a yellowish brown oil of such extraordinary viscosity a n d tackiness t h a t i t resembles melted India rubber: exposure t o air resulted in its drying t o a TOTAL moderately h a r d b u t highly elastic skin. -Hours-DaysPer 1’LHIOLI 24 48 72 96 9 t h 23rd 43rd 74th 135th cent A cursory examination of these two oils side by side, Ether Extract 67.50 3 . 9 6 0.93 1 . 1 1 2 . 8 0 3 . 6 1 1.66 2.10 1.65 85.32 considered from t h e point of view of their bearing on T h e above values when plotted in form of a curve t h e physical properties of t h e skin from which t h e y with per cent extract as ordinates a n d time as abscissae originated, would a t once suggest t h a t t h e quality of give a parabolic figure. F r o m a consideration of t h e t h e latter would be proportional t o t h e quantity of t h e enormous number of continuous extractions t h a t t h e ether extract, a n d inversely so t o t h e petroleum ether substance must have receiT-ed a t t h e end of t h e period extract, t h e residual linoxyn affecting t h e “body” or quoted without a n end-point having been obtained, it solidity of t h e whole. This expectation has been fully seems highly improbable t h a t t h e simple explanation realized, so t h a t t h e valuation of various samples has of high insolubility of a n y particular constituent would been performed by me b y these means €or a conserve. T h e explanation suggested would be rather siderable time past. Before proceeding t o t h e description of t h e uses of t h a t of either t h e solvent having t h e definite effect of slowly rendering soluble a previously insoluble sub- this test in other directions, i t will be as well t o append stance, or else t h e extracted portion consisting of two t h e d a t a obtained in t h e hitherto unsuccessful a t distinct bodies of vastly differing solubilities, t h e less t e m p t s at solving t h e composition of t h e fractions.
Jan., 1917
T H E J O U R N A L OF I N D U S T R I A L A S D ENGI;VEERING C H E M I S T R Y
I n t h e following, linoxyn (so named b y t h e Dutch chemist hlulder) will b e considered t o represent t h e body which is insoluble after successive extraction with petroleum ether a n d finally ether, t h e petroleumether-insoluble b u t ether-soluble extract being simply named “ether extract.” T h e following figures have been obtained from various samples as necessity arose; i t 1%-illbe seen t h a t wide variations occur in many cases. This m a y be due either t o actual differences in t h e ultimate composition of various samples or t o t h e fact t h a t distinct fractionation cannot be obtained, owing t o insolubility in a given solvent being only relative as stated above. PETROLEUMETHER ETHER LINOXYN EXTRACT EXTRACT 5 1 . 5 51.8 58.0 81.6 8 8 . 4 88.6 3 9 . 5 41.4 53.9 87. 1 57.8 43.0 $6.5 89.3 89.0 f5.9
Iodine value (Wijs). . . . . . . . . . . . . Iodine value ( H u b l ) , . . . . . . . . . . . Iodine value (modified Waller). Iodine value (from Br value). . . . Iodine substitution (from B r value) . . . . . . . . . . . . . . . . . . . . . . 24.9 Saponification value.. . . . . . . . . . . 250 262 254 Acid value.. . . . . . . . . . . . . . . . . . . . per c e n t , ,, , 48.6’i0:7 “Oxidized 53.0 5 6 . 6 F a t t y acids freed (from above 12.9 15.8 per cent) . . . . . . . . . . . . . . . . . . 1 5 . 3 1 3 . 3 True acetyl value. . . . . . . . . . . . . . . . .
..
1 1
11.2
12.5
3i:l 46.9 41.7 48.5 45.4 13.5 17.9 23.8 2 1 . 6 110.4
22:5 14.5 72.5 48.9
The distribution of t h e various fractions in average “skins” of oxidized oil is given in t h e follon-ing table: XO, 1 2 3 4 5 6 7 Linoxyn . . . . . . . . . . . . . . . . . . 49.57 47.08 43.62 48.41 49.22 57.09 42.46 Ether extract.. . . . . . . . . . . . 31.16 26.79 27.93 29.38 25.45 2 5 . I 6 32.91 Petroleum-ether extract . . . . 19.2; 26.13 26.45 22.21 25.33 17.75 24.63
A wide \,ariation also occurs in t h e an:tlyses of such oxidized oils t o which reference will be made later, t h e above figures being shown merely t o give a general idea of t h e composition of skins as ordinarily obtained in large scale practice. It will be noted t h a t in Nos. I t o 6, S o . I shows t h e highest proportion of ether extract, b u t as t h e advantageous significance of this is somewhat neutralized b y t h e high linoxyn which would reduce its fusibility t o below t h e favorable limit, it would thus be adjudged equal only t o No. 3, taking all three constituents into consideration. KO. 6 would be classed as a poor sample. KO.7 is a skin made with a specially chosen drier a n d as seen from its analysis would be adjudged as of excellent quality, and such indeed i t proved in practice. For purposes of comparison t h e following table gives t h e extraction analyses of oxidized oils prepared by t h e Walton “shower b a t h ” process: No. 1 Linoxyn ......................... 40.2 Ether extract.. . . . . . . . . . . . . . . . . . . 3 5 . 0 Petroleum ether extract . . . . . . . . . . . 24.7 h70TE.-No. 5 represents oil as turned the same oil after further treatment in the
2 3 4 3 2 . 4 5 0 . 0 42.2 38.1 3 0 . 3 3 1 . 2 27.7 1 8 . 3 ;!6.3 o u t of t h e smacker, ovens.
5 37.4 29.6 33.0 ?io. 4
6 37.7 34.9 26.4 being
I t will be seen from these analyses t h a t , according t o the principles I have stated as governing the valuation of oxidized oils, t h e “shower bath” products are vastly superior t o those obtained b y the “scrim” process. T h e higher ether extracts in t h e former case indeed have t h e very definite effect in t h e finished cements of increasing t h e “covering power,” or power t o absorb fillers (cork, pigment, etc.), b u t t h e principal advantageous difference is t o be noted in t h a t none b u t cements made with t h e “shower b a t h ” process are capable of being used for t h e new “Walton In-
I1
laids.” These products, owing t o the exigencies of the mechanical treatment involved, necessitate a degree of tenacity and binding power in t h e cement t h a t is quite unobtainable in t h e case of those made b y t h e “scrim” process. A later remark will make this point clear. T h e impossibility of making inlaid linoleums n-ith Taylor-Parnacott or Corticine oil is shown by the following extraction analysis: LINOXYN 60.4
ETHEREXTRACT PETROLEUM-ETIIER 1Smn ~ C ’ I 9.6
30.0
This also explains t h e low covering power of t h e oil, t h e proportion of oil t o filler being usually I O O : 106 as against I O O : 2 0 0 in t h e Walton cements. USE O F GUM KAURI
Before proceeding t o t h e description of a n investigation I have undertaken in order t o determine t h e influence of t h e rosin a n d gum resin on the final product, a word here is necessary as t o t h e particular reason for which g u m kauri has been adopted. Walton’s original patent for t h e preparation of cement from oxidized oil specifies t h e use of gum kauri in conjunction with rosin. I t is t o be remarked t h a t kauri gum a t the present d a y can be obtained only a t a very high cost. The scarcity of t h e gum is consequent upon t h e huge drain on t h e deposits occasioned b y t h e demand for linoleum manufacture. T h e constantly increasing price since t h e ’60’s is most probably t o be attributed t o this cause, a n d a t t h e present time, g u m is actually being sold which has been obtained from t h e screenings or rejected portions of previously “mined” deposits. A t t h e same time i t would be unfair t o t h e linoleum manufacturers t o s a y t h a t no a t t e m p t has been made t o find a substitute for this gum. Taking into consideration this question, we haye t o bear in mind t h a t the g u m resin adopted for use in cement making must conform t o the following requircments : ( I ) The melting or softening point, although not needing t o be kept t o t h e low limit of t h e temperature of “cementation,” should be sufficiently low t o allow n homogeneous amalgamation t o t a k e place at I j o o C., when in presence of a large quantity of a n already melted flux-in this case rosin a n d molten oxidized oil. Such requirement eliminates the harder fossil gum resins, such as t h e African Copals, etc. At the same time t h e melting point must be sufficiently high t o furnish t h e body or solidity necessary t o t h e cement, This is t h e n t h e reason why rosin alone is not used. T h e latter requirement eliminates t h e softer gums (such as dammar, manila) appearing below kauri in t h e scale of hardness. ( 2 ) For the manufacture of linoleunis in which t h e ground appears, e. g., “plains” and “inlaids,” the g u m resin employed should have t h e least appreciable darkening effect possible. Asphaltum and t h e various pitches are thus eliminated. (3) T h e stability or resistance t o spontaneous (lecomposition and atmospheric influences should be n t a minimum. Rosin behaves unfavorably in t h i s respect.
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING CHEMISTRY
I2 ATTEMPT
I
TO
SUBSTITUTE CHINA KAURI
WOOD
OIL
FOR
GUM
I n view of t h e above considerations, however, a substitute has been patented, t h e claim t o efficacy of which appears somewhat remarkable. I refer t o t h e use of china wood or t u n g oil. If this oil be held at a temperature of from 180 t o z j o o C,, a s u d d e n p o l y m erization or gelatinization occurs, t h e center of t h e solidified mass being very h a r d a n d elastic, while t h e outside portions (which do not so persistently retain their heat during cooling) are possessed of a n extraordinary tackiness. Under carefully chosen conditions a balance m a y b e struck as regards t h e proportion of inner solid portion a n d outside t a c k y portion, so t h a t t h e whole, when mixed through rolls, a t first sight would give t h e impression of being a n ideal material for use as a basis or binder for linoleum. This phenomenon has long been known among oil technologists, b u t t h e difficulties of controlling t h e solidification have more t h a n neutralized t h e a d vantages which this oil seemed t o offer i n t h e short time necessary for its solidification (on t h e laboratory scale IOO g. can be solidified at 2 5 0 ’ C. i n 5 t o 8 minutes). Certain othkr workers, rather more successful i n t h e control of t h e polymerization process, have made serious a t t e m p t s t o use i t as a linoleum material; b u t t h e promising tackiness sekmed t o disappear entirely as soon as amalgamation with filler was made. It occurred t o me t o investigate this failure t o bind, b y t h e extraction method described, a n d as a result I found my previous postulation of t h e necessity of high ether extract fully borne out. While I could regulate t h e amount of “linoxyn” or solvent insoluble portion within t h e very wide limits of 30 per cent t o 9 2 per cent quite easily when certain principles were borne i n mind, t h e ether extract i n n o case was higher t h a n 1.1 per cent. A recent German writer has suggested t h a t t h e tacky portion probably consists of a gel of t h e insoluble ‘‘linoxyn” i n unpolymerized oil. While having insufficient evidence t o agree entirely with this s t a t e m e n t I may mention t h a t t h e extractable portion possesses no tackiness such a s was observed i n t h e case of oxidized linseed oil extracts, being merely a t h i n greasy oil. T h e result of this disqualification of wood oil as t h e principal basis for linoleum, has, however, not been t h e means of causing its entire dismissal from t h e industry a n d i t appears i n t h e p a t e n t literature as a substitute for kauri gum. B y this 1 mean t o infer t h a t t h e patentees quote formulas for linoleum in which polym&zed wood oil is used in conjunction with ordinary oxidized oil a n d rosin i n t h e absence of gum. I n view of t h e wholesale condemnation of such subs t i t u t e b y a German writer 1 have thought i t of interest t o investigate this point, using t h e method of valuation described as m y basis of judgment. It might be imagined a t first sight t h a t t h e ad&tions of rosin a n d g u m kauri t o t h e oxidized linseed oil in t h e cement p a n might be made in order t o induce a n economy i n t h e final product. Without entering too deeply i n t o a discussion as t o how far economies in t h e materials are borne o u t i n t h e final product, t h e
T‘ol. 9 , KO. I
whole question can be easily a n d finally decided b y t h e statement t h a t a linoleum cement t o be cheap must be capable of taking u p t h e maximum amount of filler, as cork or wood fiber, a n d pigment. Now for a reason which will become apparent when t h e experiments t o be described a r e discussed, a p a r t from t h e binding effect of t h e resins 9er se, t h e y have a very definite influence in advantageously modifying t h e covering Power of t h e oil with which t h e y are admixed. For effecting such change, in common with all chemical reactions, i t must be presumed t h a t a certain a m o u n t of solution of t h e resins i n t h e oil, or vice verse, must occur. Coming now t o t h e consideration of t h e employment of solidified wood oil in place of t h e g u m kauri, t w o methods of employment of t h e same have been suggested. I n t h e first, mere admixture of “cement” with solid wood oil a n d t h e usual fillers is made on t h e rolls. T h e judgment as t o t h e utility of this is n o t difficult t o arrive a t . If t h e solid wood oil be prepared i n t h e t a c k y condition, no increase i n covering power will result, as I have already pointed out, a n d in f a c t t h e greasy softness of t h e product will be detrimental t o t h e finished article. A certain a m o u n t of diminution of extract of t h e actual wood oil will naturally t a k e place during t h e subsequent maturing process, b u t it is nevertheless considered as a sine qua non b y experienced manufacturers t h a t t o obtain a satisfactory finished cloth t h e linoleum a t t h e intermediate stage of manufacture must be good, otherwise t h e cohesion of t h e individual components will be unsatisfactory. I n t h e second suggested process which forms t h e subject of a p a t e n t specification, t h e ground solidified wood oil is mixed i n along with rosin a n d oxidized oil in t h e cement p a n a n d t h e mixture converted i n t o cement i n t h e ordinary way. I t is further claimed t h a t t h e solid wood oil when admixed with oxidized oil will t h e n r u n down a t t h e temperature of t h e cement Pan (130 t o 150’ cs). Now, unless t h e latter claim is substantiated a n d some transformation t o a soluble or miscible f o r m of t h e wood oil takes place as suggested, this Process differs i n no way f r o m t h e previous. We need not enter into a discussion as t o whether a n oil polymerized a t a minimum temperat u r e of 180’ c. can be caused t o melt alone at 130 t o 1 5 0 ’ c , ; i t merely remains t o consider whether t h e oxidized Oil Or rosin can have a n y influence. T h e experiments which I shall describe were undert a k e n among other things t o investigate this particular Point, b u t i t m a y be s t a t e d t h a t i n a series of m a n y other experiments unpublished i n this communication, no melting of t h e solidified wood oil could in a n y case be observed. I n every case t h e finished Cement was examined under a microscope a n d t h e individual sharp cornered pieces of t h e ground wood oil were seen without a n y difficulty. However, my conclusions were not based entirely on such method Of investigation, b u t as follows: COMPARISON
OF LINOXYN
A N D “CYCLOLIN”
I n t h e course of some investigations on t h e n a t u r e of t h e comparatively ether-insoluble body linoxyn a n d on comparisons between i t a n d t h e insoluble body
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y
J a n . , I917
obtained b y polymerizing a linseed oil b y heat ( a body I have provisionally named cyclolin i n reference t o i t s supposed ring structure) I found a very definite distinction between t h e two bodies. T h e following table gives a preliminary comparison of certain of their more i m p o r t a n t properties, t h e one under discussion being left till t h e l a s t :
..... .
Appearance, etc. Saponification value.. Saponifiable.. Stability.
........
............
Oxidized acids.
......
LINOXYN CYCLOLIN Leathery yellow t o yellowish brown solids High (see above) Not increased over raw oil By 1 per cent aqueous Difficult t o saponify NaOH in the acid even by alcoholic potash Spontaneously slowly Very stable indeed. evolves acid volatile Samples kept for 18 products and ultimos not appearing m a t e l y liquefies t o change About 50 per cent Nil (see above)
P ~ R C E N T A C E S No. 1 Oxidized Oil . . . . . . . . . . . . . 85.0 Rosin . . . . . . . . . . . . . . . . . . . 5 . 0 Gum .................... 10.0 Solid Wood O i l . .
...........
2 3 81.0 79 9.5 7 7 9:s 7
4 90 10
I3 5 81.0 9.5 9.5
6 90
7 90
8 100
....... .. 10 ..... . . . . . . 10 ...
T h e particular compositions chosen were those which would be actually practicable from conditions of not only limitations of cost b u t considerations of working practice. M E T H 0 D S 0 F E X A >I1 N AT1 0 N
A q u a n t i t y of t h e middle portions of a batch of “skins” was chosen having a sufficiently high extract t o enable t h e m t o melt without t h e addition of a n y added resinous flux. -4 very careful sampling was performed, the sample chosen being t h e n ground t o a meal i n t h e manner described and t h e n extracted with petroleum ether for 24 hours in a Soxhlet extractor. T h e extract was evaporated, t h e last traces of solvent being driven off in a current of COZ. T h e insoluble residue was t h e n freed as far as possible from petroleum ether, a n d further extracted with ordinary 0 . 7 2 0 methylated ether for 24 hours. T h e ex-tract was t h e n evaporated a n d weighed as before. A check determination b y extracting with ether in t h e first instance showed t h e total extract obtained in t h e t w o steps described above t o agree with this within very narrow limits. Such analyses appear i n t h e accompanying figures as t h e “theoretical” or “calculated” values in t h e case of those compositions containing no added wood oil. I n t h e case of other compositions containing wood oil, i. e., i n Nos. 2 , 3 a n d 7 , t h e “theoretical” or L ‘ ~ a l ~ u l a t e dvalues ” represent t h e analyses of t h e resin-free mixtures of oxidized linseed oil with polymerized wood oil, as obtained both from separate analyses of these two constituents a n d b y analysis of t h e mixture. T h e “observed” values in t h e case of compositions containing resins are obtained b y deducting t h e a m o u n t of resin mixture added originally, from t h e petroleumether extract a n d calculating this residue t o I O O parts. T h u s t h e t r e a t m e n t of t h e appended hypothetical composition would be as follows:
Pursuing t h e clue afforded b y t h e continuous solubility of linoxyn i n ether, i t occurred t o me t o employ a solvent of higher boiling point i n order t o accelerate solution. T h e use of amyl alcohol i n this respect was very remarkable. I n t h e case of linoxyn, t h e substance swelled when heated i n this solvent a t 120’ C. a n d i n 6 t o 1 2 hrs. went entirely i n t o solution. T h e substance left b y evaporation of t h e amyl alcohol was a viscous t a c k y oil possessing all t h e properties of ether extract from oxidized linseed oil. F u r t h e r investigation is proceeding a t present b u t it m a y be remarked t h a t neither t h e saponification nor iodine values were altered b y t h e process of solution. T h e cyclolin on t h e other h a n d swelled t o a certain extent a n d some slight solution occurred as seen b y t h e yellow coloration i n t h e amyl alcohol. It was heated for 7 2 hrs. a t 120’ C., cooled, a n d t h e solution decanted off. T h e residue was washed, again heated up for 24 hrs., decanted off, washed, a n d in further t r e a t ment, even u p t o another 7 2 hrs., no further solution occurred even i n traces. T h u s i t was possible t o obtain a distinctly insoluble portion from t h e cyclolin, t h e a m o u n t being roughly 80 per cent of t h e total. Similar experiments on oxidized oil from other sources a n d polymerized wood oil showed a general rule t o hold t h a t oxidized oils are completely soluble while polymerized EXTRACTIONResin-free Extraction Analysis COMPOSITION ANALYSIS per 100-20 pts. per 100 pts. (solid) oils contain a n insoluble portion. Oxidized Oil 80 Linoxyn 40.0 40.0 50.0 Such was t h e method adopted for recognizing a n d Rosin 10 Ether Extract 30.0 30.0 37.5 Petr.-EtherExt.30.0 10.0 12.5 Gum Kauri 10 isolating t h e unchanged polymerized wood oil i n A long series of experiments has led me to the cements. I n every case i n which ground polymerized wood oil was used, its presence could be recognized b y conclusion t h a t t h e resinous matter, after conversion t h e above described t r e a t m e n t on t h e cement. It of t h e mixture into cement, is t o be found entirely in remained yet t o determine if, i n spite of t h e insolubility t h e petroleum-ether extract. T h e combination of t r u e of t h e major p a r t of i t , i t h a d a n advantageous or other ‘(petroleum-ether extract” of t h e oil acting in coninfluence on t h e oxidized oil. Should t h e conclusion junction with t h e petroleum ether seems t o act as a be reached t h a t it was without beneficial influence perfect solvent for both g u m kauri a n d rosin. o n t h e oxidized oil, it would still unfavorably affect t h e Fig. 11, embodying t h e order of quality of t h e cement i n t h a t , it being n o better t h a n so much filler, cements from t h e analytical values, is obtained b y t h e t h e actual covering or binding power of t h e cement obvious method of allotting positions of merit t o t h e would be decreased b y a n a m o u n t proportional t o t h e individual cements separately from t h e parts of Fig. I solid wood oil present. a n d showing t h e s u m total of such figures as “negative T h e investigations undertaken were as follows: points.” T h e same t r e a t m e n t has been adopted i n t h e Comparisons of analyses of actual oil before a n d after lower p a r t of Fig. IV. conversion i n t o cement. Fig. I11 was compiled b y treating t h e analytical Comparisons of analyses of actual oil existing in figures as before, small corrections being however linoleum before a n d after maturing, on typical com- necessary t o allow for t h e cork a n d wood extracts of positions consisting of: t h e linoleum composition.
T H E J O U R N A L O F I N D C S T R I A L A.VD ENGINEERI-VG C H E M I S T R Y
I4
Fig. V needs little explanation. T h e testing was performed o n unit width on a dynamometer a n d i n a n y case t h e values obtained are strictly comparative. F I G U R ~I
will be observed t h a t in all cases a loss of linoxyn has occurred. T h e importance of t h e proportion of this constituent is not great provided t h a t t h e percentage remains within certain limits. T h u s No. 4 cement we should pronounce as being somewhat too soft for very successful working as t h e effect of such softness would be a disadvantage for LINOXYN-It
1151--
I --
2 n
3
4
.
5
6
+7 - 8-
Vol. 9, KO.I
sideration of many experiments seems t o point t o t h e fact t h a t i t is influenced b y two distinct reactions. One of these is due t o t h e influence of gum, which, when present, seems t o increase t h e linoxyn a t t h e expense of t h e petroleum-ether extract. With t h e exception of cement No. 4 i t will be seen t h a t only those compositions containing g u m have materially decreased in petroleum-ether extract during t h e cementing process. T h e other reaction appears t o be a n exchange of linoxyn for ether extract during t h e cementing process, t h e a m o u n t t h u s exchanged being proportional t o t h e total resin present a n d t h e g u m kauri having a decidedly stronger effect t h a n t h e rosin. Such hypothesis afforded me a clue t o a furthes investigation in which I endeavor t o submit analogy with t h e phenomena mentioned earlier i n t h e communication. I refer t o t h e continuous solubility of linoxyn in certain solvents (ether, acetone, etc.) together with t h e complete solubility in amyl alcohol a n d acetate. It will be interesting t o mention t h a t other solvents were tried, among t h e m being coal-tar n a p h t h a , turpentine a n d benzene, a n d i n none of these cases was 2
8
FIG.11-NEGATIVEPOINTSOBTAINED FROM ANALYTICAL D A T AON
EXPERIMENTAL CEMENTS
i t possible t o obtain solution as i n t h e case of amyl alcohol a n d acetate. A generalization as t o t h e class of compounds which effected solution as distinct from t h e others, I have hitherto failed in, beyond t h e general s t a t e m e n t t h a t a body t o act as a solvent must contain oxygen i n its molecule. An experiment in which rosin at a temperature of 120’ C. was used showed t h a t it behaved i n a manner exactly similar t o amyl alcohol a n d acetate. T h e mass obtained was perfectly transparent a n d was soluble t o a clear solution i n ether, b u t i n petroleum ether showed a n inObserved nCa/cutafed -Difference soluble fraction of a n oily nature. T h e t w o fractions F I G . I-COMPARISONOF PERCENTAGE COMPOSITION OF OILS EXISTING obtained may possibly be identical with “ether exI N CEMENTS wxtn THATCALCULATED FROM THEORETICAL t r a c t ” a n d “petroleum-ether extract,” which would manufacture of inlaid linoleum, t h e rigidity of t h e indicate t h a t t h e reaction occurring i n t h e cement pan is very far-reaching a n d complex. A similar inlaid “unit” being affected b y t h e softness. T h e disappearance of linoxyn during cementation is experiment with rosin as a solvent a n d employing a n interesting point. T h e fact t h a t t h e proportion polymerized wood oil showed perfect analogy with t h e of linoxyn present influences t h e “body” of t h e product other solvents, a n insoluble residue being obtained shows t h a t some softening occurs during t h e trans- nearly equal i n a m o u n t t o t h e solid oil originally used. formation a n d again indicates t h e probability of t h e This, I submit, completely confirms my other experireaction not being due t o polymerization. T h e ments a n d shows t h a t solidified wood oil undergoes no amount of linoxyn present i n t h e cement from con- transformation during t h e cementing process. Con-
Jan., 1917
T H E J O 11R N A L 0 F I N D U S T RI A L A 1TD E -VGI N E E RI iVG CI€ E 1441S T R Y
sideration of the figures will show t h a t this is fully borne out, those cements containing wood oil being decidedly inferior in every way t o those containing gum. T h e direct comparison of g u m with wood oil is easily seen b y comparing compositions S o s . 6 and 7 , although I should like t o state t h a t rosin has its own
!
Z
3
7T-----1 60
II..-
I
I
-4
4
5
6
7
&
15
rather higher t h a n would correspond with a good skin, and it may be remarked t h a t the gum v s . wood oil differences would be far more apparent if a n oxidized oil with a n extract just sufficient t o run down had been chosen. E T H E R EXTRACT-The formation Of ether extract by means of resins is well demonstrated here, the resinfree compositions 7 and 8 being markedly deficient in this respect. T h e comparatively small increase (see difference column) in the case of No. z is probably accounted for b y t h e wood oil diminishing as it were t h e concentration of t h e rosin by its presence. P E T R O L E U M - E T H E R EXTR4CT-Here t h e effect produced b y economy of gum as predicted earlier is well shown. T h e compositions containing no gum ( S o s . 2 , 4, 7 and 8) are remarkable in showing a high percentage of the petroleum-ether extract, while 1 0 s . 2 a n d 7 have actually gained in this constituent during cementing. I t should be mentioned t h a t S o . 5 is t h e standard composition used b y most linoleum manufacturers. F I G U R E I11
LIxoxYx-It is necessary here t o s t a t e t h a t this constituent should be high in a matured linoleum, t h e body or hardness of t h e product being dependent
P O l X T S OBT.4INED FROM ANALYTICAL DATAC O X THOSEOBTAIXEDFROM THE MEAN RESULTSOF FOUR INDEPENDENT OBSERVERS‘ PRACTICAL TESTS
F I G . IV--h’EGATIVE PARED WITH
on this. G u m itself, however, confers a very great degree of resistance t o wear a n d has the advantage of being resistant t o atmospheric influences and spontaneous decomposition. T h e wood oil linoleums here show up rather better on account of t h e contained wood oil consisting of about 9 1 per cent of linoxyn. E T H E R EXTRACT-The pliability and cohesion Of t h e finished linoleum is absolutely dependent on t h e proportion of this constituent a n d t h e l b s s during maturing should be as little as possible; the increase of linoxyn during maturing should depend as far as possible for its formation on t h e petroleum-ether extract. I t will be seen t h a t t h e smallest loss occurs in t h e case of No. 5 which composition also shows t h e highest proportion. It will also be noticed t h a t t h e B e f o r e M a f m g =After Maturing m D i f f e r , - n c e typical practicable wood oil linoleum, No. 2 , shows u p F I G . 111-COMPARISONOF-PERCENTAGE COMPOSITION OF OILS EXISTING at a disadvantage in this important table: No. 7 I N C E M E N T S - B E F O R E A N D AFTER MATURING I N LINOLEUM shows up even less favorably t h a n t h e No. 8 “all-oil” particular decided function especially in t h e form of composition. gum-rosin mixture. P E T R O L E U M - E T H E R EXTRACT-This table is Very imI. further statement is necessary t o t h e effect that portant in t h a t a linoleum with a high percentage of on account of t h e necessity of experimenting with com- this constituent will have a characteristically flabby positions containing no added flux (Nos. 7 a n d 8) i t or “rotten” feel and be of open non-cohesive texture. was expedient t o employ a n oxidized oil with a n extract T h e standard g u m rosin linoleum, No. 5 , again ap-
16
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y
pears first i n t h i s table while t h e typical wood oil rosin linoleum, No. 2 , appears distinctly inferior t o it. Looking a t 7 a n d 8, t h e failure here appears t o be not so much wood oil as absence of resins. FIG. Iv-The comparison of agreement between t h e analytical d a t a a n d t h e practical tests in these tables cannot, i t must be remembered, be quite perfect owing t o t h e ’ f a c t t h a t t h e former takes no cognizance of t h e properties intrinsically conferred on t h e linoleums b y t h e physical properties of t h e non-oily constituents of t h e cements. Taking into account m y previous statements as t o t h e advantages accruing from t h e presence of t h e g u m itself (within certain definite limits, No. 5 composition being considered t h e ideal mixture) a n y tendencies t o show t h e g u m cements as favorable in t h e upper table ought t o be amplified i n t h e lower table. FIG. v-It will be seen t h a t generally speaking t h e
FIG.V-TESTS
OF
EXPERIMENTAL LINOLEUMS
more resinous linoleums are less porous (and t h u s more resistant * t o disintegration b y d a m p ) t h a n t h e others, t h e stdndard No. 5 linoleum being t h e best i n this respect. T h e impermeability of No. 4 is explained b y t h e fact t h a t t h e low melting point rosin has been brought t o t h e surface b y the hot rolling t r e a t m e n t t o which t h e cloth was subjected. Indeed on rubbing lightly with t h e hands, t h e presence of a sticky coating was made apparent. T h e adhesion t o canvas is a n important consideration, separation of canvas a n d body, especially i n t h e case of “granular inlaids” linoleum, being more common t h a n is generally supposed when t h e cloth is laid on a floor which has a tendency t o dampness. Lack of adhesion is due t o b o t h absence of g u m a n d a low “ether extract” a n d t h e table bears out well t h e superiority of linoleums containing gum. T h e general conclusions t o be derived from these analytical d a t a are therefore summarized as follows: ( I ) T h e presence of resins t o a full 20 per cent of t h e cement is essential t o obtaining t h e maximum transformation of t h e oily m a t t e r during cementing t o a material with high binding power. ( a ) T h e said transformation is t o o far-reaching if t h e oily resin present is rosin, i n t h a t t h e body (as measured b y linoxyn) is liable t o diminish t o below t h e limit fixed b y working conditions. (3) T h e presence of g u m is essential t o secure t h e diminution i n greasiness (petroleum-ether extract).
Vol. 9, No.
I
(4) T h e chemical influence of wood oil on t h e cement p a n transformation is nil, t h e apparent disadvantages from i t s presence being merely made u p of t h e diminution of action taking place, owing t o t h e smaller a m o u n t (lower concentration) of oxidized oil present. ( 5 ) T h e best balance of oil-gum-rosin is i n t h e proportion of roughly 80 : I O : I O , no advantage being obtained b y diminishing rosin a n d consequently increasing t h e cost. These conclusions apply merely t o t h e chemical properties, t h e general physical qualities of t h e various compositions being further influenced according t o t h e particular non-oily matter present. T h e concluding test t o which t h e several linoleums have been subjected was t h a t of actual wear under s t a n d a r d conditions. It may be remarked t h a t i n order t o get strictly comparative results of such wearing tests a good deal of difficulty is experienced i n according equal conditions t o all of t h e several products examined. T h e best method is t o map o u t a ground plan carefully, a n d t o subdivide t h e pieces into m a n y units, repeating individual samples two, three or even more times. After a period depending on t h e heaviness of t h e traffic, a careful examination is made a n d comparisons noted between each particular piece a n d t h e one immediately adjacent. By a process of classification t h e result of observation i n t h e form of “A in better condition t h a n B, B in better condition t h a n C, etc.,” a n d collating together duplicates, a rCsumC can be arrived a t which shows t h e relative order of resistance t o wearing. It m a y be s t a t e d t h a t i n these particular tests another series of samples was arranged on stairs attached t o a building o u t of doors. These l a t t e r tests yielded more marked results t h a n t h e indoor tests. T h e results appear i n t h e following order, t h e linoleum showing t h e highest resistance being placed first: 1st No.5
2nd Nos. 1 & 6
3rd No.3
4th No 4
5th No 2
6th Nos.7&8
Apart from t h e foregone conclusion showing t h e necessity for t h e presence of gum i n linoleum, t h e result is interesting i n t h a t i t shows t h a t t h e s t a n d a r d composition No. 5, consisting of a cement made with I O per cent each rosin a n d g u m kauri t o be t h e best, i n spite of t h e fact t h a t Nos I a n d 6 are made with more expensive materials, i. e . , t h e cheaper constituent rosin is highest i n t h e case of No. 5. It being beyond t h e purposes of this communication t o deal with a description of t h e mechanical processes involved in t h e manufacture of linoleum, I t h i n k it however necessary t o qualify my previous s t a t e m e n t as t o t h e necessity for employment of gum-rosin cements from “shower b a t h ” oxidized oil in t h e new Walton inlaids. These products will be familiar t o all as t h e inlaid or “solid right t h r o w h to t h e back” linoleums which have a s their distinguishing feature a sharpness of outline of t h e individual figures or units. I exclude, however, under this denomination, imitations of parquet flooring which are made b y stamping t h e figures o u t of a sheet, reuniting t h e m b y h a n d o n a table a n d consolidating a new sheet under a hydraulic
Jan., 1 9 1 7
T H E JOURiVAL OF I.VDL-STRIAL A N D E-VGINEERING C H E M I S T R Y
press. T h e TValton inlaids are of t w o kinds, those i n which t h e individual figures a r e “solo” or shaped i n a definite (usually floral or scroll) p a t t e r n a n d those i n which a particular figur,e is composed of a number of little squares or hexagonal units known a s “universal” patterns. In t h e case of the square units, t h e designer h a s at his disposal a n y combination of p a t t e r n which c a n be made b y coloring singly or collectively t h e squares on a piece of squared paper. T h e actual mechanical t r e a t m e n t is briefly t h e s t a m p i n g o u t of t h e desired units f r o m several sheets of different colors and the transference of such cut-out pieces on t o a roller fitted with pins where t h e reunited pieces a r e t e m porarily held previous t o their subsequent transference on t o t h e canvas backing. The point I wish t o d r a w attention t o is that i n order t o allow t h e several colored sheets t o be brought simultaneously together on t o t h e cutting roller t h e y need t o b e suspended without a n y s u p p o r t whatever i n t h e bight i n lengths of several feet i n mid air i n a nearly horizontal position. T h u s the cohesion of t h e sheets, which i t m u s t b e remembered a r e i n t h e “green” or u n m a t u r e d condition, m u s t be v e r y great indeed, and i t has been found b y experience that none b u t t h e t r u e Walton shower b a t h oil cements made with t h e original materials specified b y t h e inventor a r e capable of undergoing t h e exigencies of such t r e a t m e n t . I h a v e referred earlier t o the possibility of obtaining yet a f o u r t h fraction f r o m a solid oxidized oil. If t h e petroleum-ether extract be dissolved i n petroleum e t h e r a clear solution will be obtained which, however, on dilution becomes turbid, owing t o t h e separation of a n oil. T h e precipitation is complete a t an 80-fold dilution, and o n being left t o settle o u t appears as a thick t a c k y oil, a b o u t intermediate i n physical properties between “petroleum-ether extract” a n d “ether extract.” The soluble portion resembles in appearance r a w linseed oil. T h e s a m e difficulties of examination were found as i n t h e case of t h e other fractions b u t I submit, however, elementary analyses of t h e four fractions obtained i n order t o show t h a t t h e y correspond t o fractions increasing i n oxygen content. PETROLEUMRaw E T H E R EXTRACT linseed Soluble Insoluble ETHER oil ( a ) in excess in excess EXTRACT LINOXYN C . . . . . . . . . . . . . . 74.40 73.00 68.74 65.97 63.35 H . .. . 10.64 10.45 9.65 9.50 8.75 O.............. 13.96 16.55 21.61 25.53 27.90 (a) Williams, Analyst, 23 (1898), 253.
Per cent
..........
T h e insoluble fraction referred t o a b o v e c a n b e isolated f r o m a n y oil that h a s suffered oxidation (including ordinary “boiled oil”) b y dissolving t o a concentrated solution i n petroleum e,ther a n d t h e n largely diluting. T h e resultant turbidity I employ as a quick qualitative test for oxidation i n oils. T h e oxidation need n o t h a v e been sufficient t o produce linoxyn. I n conclusion I suggest that m y method of extraction analysis might b e advantageously applied t o investigations connected with t h e examination of paints a n d varnishes.
I7
ADDENDA
Fahrion‘ on the subject of the determination of “oxidized acids” separates the petroleum ether insoluble fatty acids into two portions: the ether soluble on the one hand and the ether insoluble alcohol soluble on the other. These fractions he interprets as follows: ( I ) Ether Soluble = peroxylinolic acid (C18H3204) or linolic acid in which one double bond of the two has been saturated by peroxidic oxygen leaving one double bond still unsaturated.
or linolenic acid (C18H3002) in which two of the three double bonds have been saturated by peroxide oxygen. Without discussing a t length my reaqonq for not agreeing with Fahrion’s hypothesis as to the identity of these fractions I would alternatively suggest the following hypothesis. The accepted structural formulas for the commonly occurring unsaturated acids, oleic, linolic, linolenic and eloeomargaric, all agree in showing that the limiting position of the double bond nearest the carboxyl group occurs in such manner that the length of the residual saturated group containing carboxyl is representable by CS. It is not improbable also that the end represented in the unoxidized compound by the double bond, on oxidation, would become converted into an aldehydic group under the influence of peroxide addition and subsequent hydrolysis. Indeed Bouchardl claims to have obtained phenylhydrazine compounds of the same. The physical propertie of the oxidized acids are moreover not unlike aldehyde resinss Oil oxidized to solidity is very easily and rapidly obtained in. the form of ethyl esters by boiling with three times its weight of alcohol and 2 per cent hydrochloric acid, while the free oxidized acids are practically impossible to esterify. Thus I would suggest that these acids are merely products of saponification and are not the free acids of which the glycerides constitute oxidized oil That no matter how far oxidation of an oil is developed it is impossible to obtain more than about 55 to 60 per cent of oxidized acids would lend support to the suggestion that they consist of bodies of which azelaic acid is the basic representative. Theory demands about 61 per cent of oxidized acids from a fully oxidized oil assuming them to have the formula CHO(CH2)COOH. Elucidation of their constitution is rendered difficult on account of their instability, separation from anhydride or lactonic bodies giving no end-point after as many as 16 repeated separations. Reductions by nickel and also colloidal palladium have been fruitless as the oxidized acids rapidly poison the solution. However, adopting as a basis of reasoning Fahrion’s suggestion that in the two degrees of unsaturation represented by linolic and linolenic acids, no full saturation by oxygen can take place, one double bond remaining intact, and extending this to comprise nonoxidizable olein we might apply such t o the oxidation of the glycerides as follows: Thus the mixed glyceride olein-linolin-linolenin would on full possible saturation by oxygen form olein-peroxylinolindiperoxylinolenin, while simple triolein would remain intact as such This latter point is rather borne out by the nonoxidizability of pure triolein such as constitutes the bulk of the true nondrying oils. Considering now the oxidation products of the ten possible mixed and simple glycerides occurring in linseed oil (saturated acids have not been considered for the sake of simplicity), if these are represented diagrammatically for the sake of convenience under the distinction of their unsaturated valencies, we have.
12. angea. Chem., 16 (19101, 722. Les hlatieres Grasses, 1912, 2779.
T H E JOURNAL OF I N D U S T R I A L A N D ENGINEERING CHEMISTRY
18
The calculated elementary analyses of these bodies when oxidized according to the hypothesis would be (0)
C
...... 77.4
(b) 74.8
(c)
(d)
(e)
72.5
70.3
72.5
14.0
16.9
19.7
16.9
H...... 1 1 . 7 1 1 . 2 1 0 . 6 10.0 1 0 . 6 O......
10.9
(n
(d
(h)
68.1 9.6 22.3
64.3 8.6 27.1
70.3 10.0 19.7
(i) 66.1 9.1 25.6
(3) 68.1 9.6 22.3
On comparing these figures with those agreeing the more nearly with those obtained and having chosen these, appending the approximate iodine values of “theoretical” and “found” together with the oxidized acids theoretically yielded with that found actually, we have, assuming the maximum yield of oxidized acids from an unsaturated chain to be 61 per cent:
c.................
.............. ...............
H...
0.. Iodine v a l u e . . . . . . . . Oxidized aQidS... ,.
.
72.5 10.6 16.9 80.8 20%
68.1 9.6 22.3 76.0 40%
Petroleum-Ether Extract FOUND “Soluble” “Insoluble” c . .. . . . . . . . . . . . . . . 7 3 . 0 0 Iodine v a l u e . . , . , . . ,
66.1 9.1 25.6 73.7 61%
64.3 8.6 27.1 71.6 61%
Ether extract
Linoxyn
85
The iodine value comparison I consider to be of little value as obscure reactions probably occur on such complex molecules. This is borne out by the lack of agreement in values obtained by the use of different methods (see above). That on taking another oxidized oil, fractionating by extraction, and performing elementary analyses of the fractions, slightly different results would be obtained is highly probable; in fact it is likely that the suggested formulas submitted as approximating to the theoretical glycerides are mixtures of which the most that one can say is that one particular member is distinguished by preponderating in linolenic as distinguished from oleic acid glyceride. Common sense would support the view that the insoluble fraction linoxyn is likely to preponderate in linolenic while inferior or semi-drying oils yield relatively large proportions of the less oxygenated fractions The transformation of one fraction into another as shown in the experiments merely presupposes partial exchange of acidic groups, a phenomenon already suggested in the case of polymerization a t high temperatures by Morre1l.l DUNDEE,ROSEFIELD ROAD STAINES,ENGLAND
THE REMOVAL OF BARIUM FROM BRINES USED IN THE MANUFACTURE OF SALT B y w, w. SKINNER AND w. F. BAUOHMAN Received October 18. 1916
,
T h e impurities which are found i n rock salt a n d i n naturalandartificialbrines are many, b u t f o r t h e m o s t p a r t are not substances of such a markedly deleterious character from a food standpoint t h a t t h e y aretoberegarded as seriously objectionable if, i n t h e manufacture of salt, small quantities of t h e m are permitted t o remain i n t h e finished product. This is not t r u e , however, of t h e salts of barium which occur in certain brines i n notable amounts, as, for instance, i n t h e brines from t h e Ohio Valley District of West Virginia a n d Ohio, also known as t h e K a n a w h a District. T h a t t h e Ohio Valley brines contain barium has been known for m a n y years. H u n t i n his “Chemical a n d Geological Essays”2 says, quoting Leney, t h a t t h e presence of barium salts is a constant characteristic of t h e 1
J . SOC.Chem. I n d . , 1916, Feb. 15th.
* 4th Ed.,
1891. p. 121.
Vol. 9, No.
I
Allegheny River brines a n d D r . Stieren i n t h e American Journal of Science’ gives t h e analysis of a brine from T a r e n t u m , Pennsylvania, which contained 0.0061z p a r t of barium chloride, 0.00378 p a r t barium carbonate, 0.009 j 9 part strontium chloride, a n d 8.586 p a r t s calcium chloride in 1000 p a r t s of brine. Dr. R o b e r t Peter reports in t h e Kentucky Geological Survey2 f o r 1878 t h e analysis of a brine from Clay County, K e n t u c k y , which was found t o contain 2 3 grains of barium chloride per wine gallon, equivalent t o 0.393 p a r t per 1000.
While i t has not attracted much attention, t h e poisoning of animals b y salt has frequently been noted a n d reported. Howard in 1889~reported t h e examination of a sample of salt which was supposed t o have caused t h e death of mules a n d which was found t o contain a considerable q u a n t i t y (per cent not given) of barium chloride. T h e same year he reported t h e poisoning of two horses, arsenic being suspected. An examination of t h e viscera showed no arsenic, b u t a q u a n t i t y of sodium salts, a n d t h e precipitant for t h e calcium group gave a n especially marked reaction (possibly b a r i u m ) . Several cases of poisoning of stock were reported from K e n t ~ c k y . ~N o poison could be found in t h e samples of salt examined. T w o cases of fatal poisoning of horses a n d cattle from salt have come t o t h e attention of t h e authors, t h e trouble being due undoubtedly t o t h e presence of barium chloride in t h e impure salts fed t o t h e animals. This salt was produced in t h e Ohio River District. I n 1913 a number of dairy cows i n Cincinnati were killed, death being a t t r i b u t e d t o t h e use of salt i n t h e ration. Upon examination it was found t h a t t h e salt used contained a considerable a m o u n t of b a r i u m chloride. T h e salt was produced b y a salt works i n t h e Ohio River Salt District. OBJECT O P T H E INVESTIGATION
Owing t o t h e meager information available, i t seemed necessary a n d desirable t o investigate t h e character of t h e brines of t h e Ohio Valley t o determine: (I) their normal constituents, especially their content of b a r i u m ; ( 2 ) t h e efficiency of t h e elimination of barium b y t h e methods now employed in t h e manufacture of s a l t ; (3) t h e normal a m o u n t of barium chloride t o be expected i n t h e several grades of salt manufactured f r o m these brines, a n d if, b y ignorantcor careless methods of manufacture, a n excessive amount of barium was likely t o occur i n t h e s a l t ; also t o s t u d y briefly t h e methods of production with t h e idea of suggesting, if possible, either some modification of t h e present process or t h e development of some new method of t r e a t m e n t b y which t h e barium chloride could b e entirely removed from t h e brine or reduced t o such a small a m o u n t t h a t t h e salt obtained, especially those grades known as No. I “Fine,” “Common Fine” a n d “Table a n d Dairy,” which enter so largely into products used for h u m a n food, or of grades of salt which might b e substituted for t h e m , should contain a t most only traces of barium. 1 2
3 4
Vol. 34 (1862). 56. Chem. Repi.. [ I ] 4, 2nd series, 52. West Virginia Station, Bull. 103. Kentzrcky Station Repovt, 1891, 20.
