T H E JOURNAL OF I N D U S T R I A L A N D ENGINEERISG CHEMISTRY
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I n No. 2 t h e part coming over above 260' was apparently a decomposition product; brown fumes came over and t h e temperature fluctuated. I n No. 3 t h e pitch left was coked. When cool i t was hard a n d brittle, insoluble in water, would not melt on heating, b u t decomposed. 4 small part was soluble in a solution of sodium hydroxide. The I n No. 4 t h e distillation was stopped a t 260'. pitch left was softer a n d more liquid t h a n those of t h e previous runs. SEPARATION
2 1 5-230'
OF
FRACTION
INTO
NEUTRAL
A N D ACID PORTIONS
The creosote was shaken up with several portions of IO per cent N a O H solution until all t h e acid portion was extracted, t h e neutral portion floating on t h e top. T h e liquids were separated in a separatory funnel. T h e neutral oil was t h e n shaken up with water until t h e water was neutral t o litmus. T h e sodium hydroxide solutions of t h e acid oils were t h e n acidified with dilute HC1. The oil precipitated out a n d was separated. This was washed with water until neutral t o litmus. The amounts of oil extracted by t h e successive portions of sodium hydroxide are illustrated in Table 111. TABLE111-100
CC. OF 215-230' FRACTION TREATEDWITH SUCCESSIVE 50 CC. PORTIONS OF 10 PER CENT NaOH, SEPARATED A N D ACIDIFIED PORTION I I1 I11 IV TOTAL Yield of Acid O i l . , 12 cc. 14 cc. 18 cc. 2 cc. 46 cc. Yield of Neutral O i l . . . . . . . . .. .. 38 cc. Loss....................................................... 16 cc.
.......
..
TABLEIV-EXTRACTIONSOF
250 CC. PORTIONS OF 215 TO 230'
PORTION I Creosote.. . . . . . . . . . 250 cc. Acid O i l . . 140 Neutral Oil.. . . . . . . . 98 Loss... . . . . . . . . . . . . 12
I1 250 cc. 150 100
..........
I11 250 cc. 125 93 32
IV 250 cc. 145 105
1000 cc. 560 396 44
FRACTIONATIOX O F THE X E U T R A L OIL
T h e distillation was conducted through a 12-in. Hempel column a t a rate of about 2 drops per second. T h e color of t h e fraction was light yellow, verging toward brown in t h e higher fractions. From 290' t h e temperature suddenly jumped t o 325') where practically all t h e remaining material came over, excepting a small residue of about 9 grams. TABLEV-FRACTIONATIONOF NEUTRALOIL 170; 190 195' 200: 205 210'
1 2 . 5 g. 8.0 8.0 22.0 55.5 47.5
210 215 220 225 230 235
t o 215: t o 220 t o 225: to 230 t o 235' t o 240'
2 8 . 5 g. 56.0 70.0 26.5 35.5 42.5
........................ .............................. ..................................
Total Distillate. Residue., LOSS.
FRACTIONATION
OF T H E
ACID
PORTION
240 to 245' 245 t o 250: 250 t o 255 255 t o 260' 260 t o 280' 280 t o 325O 325 to 330' 567.0 g. 9.0 19.0 OF
33.0g. 24.0 14.0 21.0 21.0 26.5 15.0
2I5-23Oo
FRACTION
The distillation was carried on in a one liter flask with a 12-in. Hempel. T h e first drops came over a t 98'. T h e fraction was a light brownish yellow which TABLEVI-FRACTIONATION OF ACID PORTION 864 GRAMSOF THE OIL FRACTIONATED
'...
215 to 2 2 5 O . . . . , 1 8 5 . 0 g. 98 to 190 ... 5 2 . 5 g. 1 9 0 t o 2 0 5O . . . . . . 95.0 225 to 240°. 70.5 (Chiefly a5203 t o 205) 240 to 260'. 77.0 205 t o 215 257.0 260 to 265'. 24.0 Total Distillate.. 761 .O g. Residue (above 265O). ..................... 21 .O Loss 82.0
......
.........................
.....................................
4
.... .... ....
changed t o a pinkish brown on standing. After standing over a month t h e fraction was a clear brown liquid. SUMMARY
I t is seen from t h e above d a t a t h a t this sample of beechwood creosote containing t a r a n d pitch distills rather uniformly from 2 0 0 u p t o 360' C. a n d leaves a residue of 2 0 t o Z j per cent pitch. If t h e temperat u r e is not carried above this point t h e pitch residue is soft a n d excellent, but above 300' i t decomposes, foams over and becomes friable when cold. When t h e creosote fraction is then redistilled in glass vessels practically no pitch residue is obtained. When t h e 215-230' fraction was extracted with I O per cent sodium hydroxide in excess t o remove t h e phenolic compounds, a yield of about 40 per cent of neutral oil and j 6 per cent of acid oil was obtained. These oils distil practically without decomposition and formation of pitch. The acid oil on redistillation gave a yield of about 65 per cent of a guaiacol fraction boiling between 190 a n d 2 2 5 ' C. FORESTPRODUCTS LABORATORY MADISON,WISCONSIN
A METHOD OF PRODUCING CRUDE WOOD CREOSOTE FROM HARDWOOD TAR By R . C. JUDD AND S. F. ACREE Received December 19, 1916
FRACTION The purpose TOTAL tical method of
... ... Table IV gives t h e total amounts of acid a n d neutral oil extracted from 2 j 0 cc. portions of t h e distilled creosote boiling a t 215 t o 230' C.
to 170 t o 190 t o 195 t o 200 t o 205 t o
Vol. 9, No. 3
of this work was t o ascertain a pracproducing on a semi-commercial scale a wood-tar creosote from crude hardwood t a r without decomposing part of t h e material in t h e still. T h e requirements t o be met are t h a t t h e method must be rapid, no coke must be left as a residue, and t h e oil shall contain as little free acid as possible. METHOD OF CONDUCTIXG T H E W O R K
Three methods of distillation were tried: I-Distillation with steam. 11-Straight distillation. 111-Straight distillation while using steam for stirring. T h e two former methods were found t o be unsatisfactory a n d are not reported here. (I) Distillation with steam gave small yields and a large amount of steam was consumed. Moreover, t h e length of time necessary t o obtain a reasonable amount of oil was excessively long. (11) Straight distillation gave good yields of oil b u t there is great danger of deep-seated exothermic decomposition of t h e t a r or pitch into gas a n d vapor when t h e temperature is not carefully controlled. This can become so violent t h a t t h e still can be blown up. Even when great care was taken there seemed t o be a slight amount of coking in t h e still which, with frequent use, would eventually cause trouble a n d perhaps ruin t h e still. This is especially t r u e when t h e temperature of t h e pitch rises above 300 t o 325' Work along this line will be reported later in detail. (111) T h e last method, v i z . , stirring with steam, gave good yields of oil, was somewhat more rapid t h a n direct distillation a n d there were no evidences of coking. It was found t h a t in t h e early p a r t of t h e distillation
c.
Mar., 1917
T H E J O U R N A L O F I N D U S T R I A L Ah’D E N G I N E E R I N G C H E M I S T R Y
steam was not necessary as there was already a large amount of water present. The distillation was, therefore, carried on t o t h e point where t h e distillate came over as a homogeneous liquid. T h e temperature was slowly raised until 100’ C. was exceeded and steam under constant pressure was then injected into t h e tar. T h e ratio of oil t o water in t h e distillate gradually decreased until only 2 j per cent of t h e distillate was oil. The distillation was then stopped. The last portion of t h e distillate on standing solidified t o a jelly-like mass because of t h e presence of paraffin. The residue in t h e still was liquid when hot and could be easily poured, b u t on cooling solidified t o a hard brittle pitch which could be powdered in t h e fingers. Special experiments showed t h n t not more t h a n z per cent of t h e t a r is lost as gas or vapors. RESULTS
The following yields mere obtained by this method of distillation : Total Distillate Oil 1st Portion of Distillate.. . . . . . . 282 cc. 64 cc. , Straight distillation.. ........ 29 cc. 29 cc. 2nd Portion of Distillate Stirred with steam.. ......... 1076 cc. 446 g. RESIDUE(by difference). ........................
No. 1-1100
g. T a r taken
Total 175 g. T a r taken Distillate Oil 1st Portion of Distillate. . . . . . . . 371 cc. 101 cc. Straight diFtillation.. 2nd Portion of Distillate Stirred with steam .......... 920 cc. 372 cc. RESIDUE(by difference).........................
No. 2-1
...........
...
Per cent in T a r 19.8 Water 8 . 5 Light Oil 4 0 . 5 Heavy Oil 31.2 Pitch
Per cent in Tar 23 Water 9 Light Oil 32 Heavy Oil
36 Pitch
The heavy oil from S o . I contained 0 . 7 per cent acids figured as acetic acid. This was reduced t o 0.3 per cent by washing three times with equal volumes of water. COIiCLUSION
I n brief, t h e following method seeems t o be a desirable one for t h e production of crude wood-tar creosote on a semi-commercial scale: ( I ) Distill with direct heat until t h e distillate comes over as a homogeneous liquid well above t h e boiling point of water. ( 2 ) Raise t h e temperature a n d stir t h e t a r with a steam jet; collect this latter portion of t h e distillate in a separate container a n d continue until t h e distillate contains solid paraffin. If t h e above procedure is carried out carefully t h e heavy oil fraction should not contain more t h a n one per cent acid a n d t h e pitch can easily be emptied without fear of coking in t h e still. Furthermore, a slight gain in time of distillation will result from t h e use of steam. LABORATORY MADISON,WISCONSIN
FOREST PRODUCTS
SOME OBSERVATlONS ON THE INFLUENCE OF HUMIDITY ON THE PHYSICAL CONSTANTS OF PAPER’ B y O r r o K R E S SA ~N D PHILIP SILVERSTEIN‘ Received January 8, 1917
Samples of paper taken for testing purposes at t h e mill a n d later at t h e point of destination may show 1 This paper represents part of the thesis presented by P. Silverstein in partial requirement for the Degree of Chemical Engineer in t h e University of Wisconsin. 9 In Charge, Section of Pulp and Paper, Madison, Wisconsin. 8 Student Research Assistant, Forest Service.
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rather surprising variations in their so-called physical constants. Paper is essentially a network of interwoven cellular fibers which may or may not be sized, loaded. calendered, coated or treated in other ways for special purposes, b u t t h e paper will still show t h e general physical characteristics of the individual fibers which make u p t h e sheet and determine its quality. I I i F L U E I i C E O F HUJIIDITY O S S T R E N G T H
Since t h e individual fibers of a sheet of paper are hygroscopic, t h e whole sheet consisting so largely of fibrous material naturally possesses this quality, though t o a lesser degree t h a n t h e individual fibers. I t is a common observation t h a t on humid days a sheet of paper is more limp, stretches more and is less resist a n t t o tearing and bursting t h a n on dry days. The relative humidity of t h e atmosphere varies from 30 per cent in cold, dry weather t o almost IOO per cent in foggy or hot, moist weather. Indoors, t h e relative humidity ranges are not so wide except t h a t on a cold, dry day t h e relative humidity in a steam-heated room often falls t o 2 0 per cent while in summer, with all t h e windows open. indoors it may be almost as high as t h a t outdoors Herzbergl in his treatise on “Papierpriifung” gives d a t a on t h e effect of varying humidities on the physical properties of paper. F r o m a study of his d a t a , i t is evident t h a t variations in t h e relative humidity of t h e atmosphere a n d consequent variations in t h e percentage moisture in t h e paper have a decided effect on t h e strength and stretch of paper. As t h e humidity falls, t h e breaking length is increased and t h e stretch decreased. Herzberg in quoting from t h e work of G. DaXn states t h a t for relative humidities between o per cent a n d 80 per cent, paper expands in direct proportion t o t h e amount of moisture present. B u t when t h e relative humidity is between 80 per cent and I O O per cent, t h e expansion is somewhat over this proportion. G. Dalgn, after many experiments on t h e effect of varying humidities on t h e breaking length and stretch of papers, constructed a table of factors b y which t h e results for breaking length a n d stretch obtained a t relative humidity are t o be multiplied t o obtain t h e correct result for 6 j per cent relative humidity. This table of factors has been published in Herzberg’s book on page 18. As a result of t h e investigations made at t h e testing laboratories in Germany, all papers for Government use are tested a t t h e Royal Testing Laboratories at Gross-Lichterfelde, under a constant relative humidity of 6 5 per cent. T h e Forest Products Laboratory has recently installed a constant humidity room in which t o s t u d y t h e effect of variations in humidity on t h e physical properties of paper. The room is double-walled, 8 ft. 2 in. X g ft. 31/2 in. X 7 ft. 6 in. high, a n d fitted with a constant temperature and constant humidity apparatus. Fig. I represents a diagrammatic sketch of t h e apparatus which consists essentially of a galvanized iron conduit A i n one corner of t h e room a n d 1
W. Herzberg, “Papierprtifung.” p.
14.
