T H E JOI‘R,VdL O F I L V D C S T R I A L AiVD E.VGILVEERI1TTG C H E M I S T R Y
Apr., 1 9 1 4
Acid Fixed Mineral value carbon matter Per 1st 2nd Per cent cent Dist. Dist.
No.
1, . . . . . 1 2 . 3 0 . . .. 9 . 9 5 3 . . . . . 15.85 4 . . . . . 10.10 5 . . . . . . 14.60 6 . . . . . 14.15 T..... 16.8i S..... 17.24 2..
4.90 35.60 Trace Trace 2.21 2.94 0.20 0.22
9.6 15.9 0.16 0.12 4.9 4.7 0.21 0.22
3.6 8.1 0.08 0 18 1.2 0.9 0.05 0.09
Sapon. value
Conclusion a s t o n a t u r e of asphalt
Bermudez 3 6 . 0 Trinidad 1 1 . 2 California 7 . 4 Maltha California 1 9 . 3 Bermudez 1 : 1 2 2 . 0 California a n d Bermudez 3 : 7 9 . 8 Mexican 1 0 . i Mexican 29,8
In concluding, I wish t o acknowledge m y indebtedness t o Dr. F. Kleeberg for his valuable advice. DEPARTMEKT OF PUBLIC XrORKS O F IIINHATTAN, h-EW Y O R K CITY BOROUGH
CHEMICAL UTILIZATION OF SOUTHERN PINE WASTE B y M. C. WHITAKERASD J. S. BATES
Received February 13, 1914
T h e utilization of nTaste resinous wood not fit for lumber is a problem of great economic importance. T h e representative species are t h e Douglas fir, t h e Norway pine a n d t h e western yellow pine of t h e Pacific slope, t h e long-leaf pine a n d t h e associated C u b a n pine of t h e southeastern states, t h e less i m p o r t a n t digger, lodgepole, sugar a n d pinon pines of t h e West a n d t h e short-leaf a n d loblolly pines of t h e South. T h e most a b u n d a n t resinous wood a n d t h e most i m p o r t a n t industrially is t h e long-leaf southern pine, Pi?zus p a l u s i r i s . As is well known, this is t h e chief mood of t h e South Atlantic a n d Gulf States a n d constitutes over one-quarter of t h e t o t a l timber c u t in t h e United States. It is estimated t h a t t h e forest areas cover over j o million acres a n d t h a t t h e s t a n d of long-leaf pine a m o u n t s t o a b o u t . 23 2 billion board feet.’ T h e utilization of this waste resinous wood is a n increasingly i m p o r t a n t factor in t h e naval stores industry. T h e virgin forests which have supplied t h e world with turpentine a n d rosin from g u m are disappearing a t a rapid r a t e a n d t h e principles of conservation demand t h a t t h e tapping a n d wasting of t h e living trees should be relieved as far as possible b y t h e recovery of resinous products from t h e felled waste \TO 0 d . COMPOSITIOS O F LONG-LEAF PISE
T h e constituents of economic value existing in longleaf pine are t h e oleoresin a n d t h e wood itself. T h e products actually obtained from t h e pine depend on t h e methods of t r e a t m e n t . T h e oleoresin varies widely in a m o u n t b u t i t s composition is fairly uniform; t h e volatile oils comprise approximately 2 0 per cent of t h e crude g u m a n d colophony or rosin makes u p t h e remainder. T h e volatile oils or “ c r u d e t u r p s ” yield from 6 0 t o 80 per cent actual turpentine a n d from 40 t o 2 0 per cent heavier oils known collectively as “pine oil.” T h e turpentine in t h e wood consists mainly of a-pinene with smaller a m o u n t s of P-pinene, dipentene, camphene a n d traces of other oils.* T h e pine oil is essentially 2
U. S. D e p t . Agric., Forest Service, Bull. 99, p. 8. I b i d . . 119, p. 7 ; Bur. Chem., Bull. 144,.p. 21.
289
terpineol, with smaller amounts of borneol, fenchyl alcohol, limonene, cineol a n d other terpenes a n d related compounds. G u m turpentine issues from t h e sapwood of t h e living tree a n d consists almost entirely of pinene, whereas t h e volatile oils of t h e heartwood contain appreciable amounts of dipentene a n d heavier oils. T h e main constituent (8-90 per cent) of t h e rosin is. believed t o be abietic acid or i t s anhydride; unsaponifiable m a t t e r usually occurs t o t h e ex’tent of a b o u t I O per cent. T h e t r u e wood, considered a p a r t from oleoresin a n d moisture, is essentially lignocellulose, macle u p of j j-6 j per cent stable cellulose, ( C ~ H I O O ~associated ),~, in a colloidal s t a t e with a b o u t 3 0 per cent lignin, a carbohydrate body approaching t h e empirical formula’ CsH703. T h e balance is made up of lower carbohydrates, chiefly pentosans a n d hexosans. a n d small a m o u n t s of protein a n d mineral m a t t e r . T h e moisture content of pine varies from a b o u t j per cent in very f a t wood t o 3-40 per cent or more in some classes of lean wood. CLASSIFICATIOh- O F W O O D WASTE
It is estimated t h a t a t least 60 per cent of t h e tree is wasted in t h e manufacture of lumber.‘ Sawdust, slabs a n d edgings represent about 3 j per cent of t h e original tree. Sawdust is usually low in oleoresin since i t s fine s t a t e of division allows more or less volatilization of t h e turpentine a n d average saw lumber is lean. Slabs are available in large quantities a n d offer one of t h e most convenient sources of raw material. Their percentage of b a r k is of course very high a n d i t s removal is a problem t o be considered. Furthermore, slabs come from t h e outer sapwood of t h e tree, where t h e oleoresin content is lowest. T h e richest slabs are those from t h e “box f a c e ” of trees which have been t a p p e d for g u m resins. Forest waste a m o u n t s t o about 2 j per cent of t h e original tree. Large branches, tree-tops a n d occasional logs left b y t h e lumbermen afford raw m a terial in forms compact enough for handling. Stumps usually have a high oleoresin content a n d their utilization is of special importance in cases where t h e land is being cleared for agricultural purposes. T h e most attractive class of forest waste is t h e “ d e a d a n d down ” material known as “lightwood.” After a tree dies t h e bark a n d outer sapwood gradually decay a n d in five t o fifteen years there is left a resinous log, which resists t h e natural processes of disintegration for long periods.3 Lightwood is often charred b y t h e ground fires which r u n through t h e pine forests. IN D C S T R I A L P R 0 CESS E S
T h e processes now employed for recovering valuable products from resinous woods have already been adequately described in THISJ 0 U R S A L . I T h e methods 1 Klason. see Schwalbe, “ D i e Chemie der Cellulose,” pp. 395 and 441, Dean and Tower, J . A m . Chem. S O C .29, , 1119; Cross a n d Bevan, “ R e searches on Cellulose, 111.” 2 U. S. Dept. Agric., Y . B. Sefi.. 634 (1YI0). 2 5 i . a Tschirch in “Die Harze und die Harzbehalter” desrrihes t h e progressive accumulation of rosin in a wounded or dead tree as a pathological process carried on by minute organisms. 4 H e r t y , THISJ O T T R N A5L, . 6.5; Teeple. 5 , 680; French and Withrow, 6, 148.
290
T H E JOURNAL OF I N D U S T R I A L A N D ENGINEERING CHEMISTRY
differ rather widely in principle a n d yield a variety of e n d products. T u r p e n t i n e orcharding provides highgrade turpentine an’d rosin b y t h e tapping of living trees. Destructive distillation of rich pine yields turpentine, rosin spirits, rosin oils, t a r oils, pitch, charcoal a n d other products. Steam distillation of shredded wood provides for t h e removal of only turpentine a n d pine oil. There has been some commercial success in extracting rosin a n d turpentine from resinous pine b y means of volatile solvents, such as gasoline a n d n a p h t h a . Rosin may also be dissolved b y solutions of alkali. I n some cases t h e volatile oils have been extracted b y hot baths of non-volatile or high-boiling material, such a s rosin, pitch, pine t a r , etc. T h e hydrolysis of t h e lignocellulose complex of wood b y dilute solutions of sulfurous, sulfuric or hydrochloric acids a t elevated pressures a n d t h e production of ethyl alcohol from the fermentable sugars so formed constitute a problem of ever-growing interest. T h e use of long-leaf pine for t h e manufacture of pulp a n d paper is a n industrial development of recent years. Several plants are already in operation in t h e S o u t h a n d other extensive projects are under way. T h e soda a n d t h e sulfate processes are preferred, while sound, lean wood is best a d a p t e d t o pulpmaking. T h e large quantities of mill waste in t h e South offer a convenient a n d cheap source of raw material. T o make t h e t r e a t m e n t of the more resinous classes of pine waste profitable, attention must be given t o by-products. Rosin a n d turpentine m a y be first removed b y a volatile solvent.’ Several of t h e methods suggested h a v e aimed a t preliminary removal of t h e volatile oils in a pure form b y distilling a t moderate pressures with s t e a m alone2 or in presence of alkali solution^.^ It has been claimed t h a t p a r t of t h e rosin can be melted down a n d t a p p e d from t h e b o t t o m of t h e digester.‘ T h e spent pulping liquors m a y be evaporated a n d destructively distilled t o yield rosin spirits, pyroligneous acid, t a r , et^.^ SCOPE O F INVESTIGATION
I n t h e chemical utilization of resinous wood waste on a profitable commercial basis, i t is essential t o aim a t simplicity of t r e a t m e n t a n d a t t h e same time provide for a complete recovery of valuable products. Under existing processes one or more of the valuable constituents of t h e wood is usually impaired or sacrificed or t h e operations involve unusual or expensive difficulties. T h e minimum number of end products is a decided a d v a n t a g e a n d all processes must be simple a n d inexpensive. It was with these considerations in mind t h a t a n investigation of resinous pine waste was undertaken. As excellent paper pulp h a d been made from longleaf pine i t seemed likely t h a t a, process might be perfected b y which t h e most valuable productsturpentine, rosin a n d pulp-might all be recovered in marketable form. Since rosin is readily saponified 1 2
8
‘ 5
Rowley, U. S. Pat. 942,106. Hough, U. S. Pat. 903,859. Craighill a n d Kerr, U. S. P a t . 817,960. Saylor, U. S. P a t . 1,004,473; Hoskins, U. S. Pat. 770,463. U. S. Dept. Agric., Bur. Chem., Bull. 159.
Vol. 6 , NO. 4
b y alkalies a n d thereby rendered soluble in water, it was decided t o make use of this principle in extracting t h e rosin from t h e wood. T h e fact t h a t turpentine a n d pine oil are volatile with s t e a m a t temperatures far below their boiling points suggested making t h e preliminary extraction a t low s t e a m pressures, t h u s allowing separation of t h e volatile oils. After removal of t h e rosin a n d turpentine, t h e chips could be steamed with stronger alkali under pressure, for t h e production of paper pulp. In addition t o t h e investigation of t h e factors affecting such a t r e a t m e n t of t h e wood, i t was important t o determine t h e quality a n d yields of t h e products a n d t o provide for their purification. There have been a number of suggestions for t h e utilization of resinous materials involving t h e principle of alkali extraction. Craighill a n d Kerrl p a t e n t e d a process b y which chipped wood is treated first with a small volume of liquor containing a n a m o u n t of caustic soda “ j u s t sufficient t o saponify t h e rosin a n d oils a n d neutralize t h e (volatile) acids without dissolving t h e other extractive matters of t h e wood.” S t e a m is a d m i t t e d long enough t o distil t h e terpenes; water is t h e n added t o submerge t h e chips in alkaline solution, a n d s t e a m ing is continued until saponification of rosin is complete. T h e solution is t h e n drawn off a n d the chips treated with a stronger caustic solution for t h e production of paper pulp. J. Aktschourin2 provides for t h e extraction of resinous material b y heating with dilute alkali below 100’ C. a t several atmospheres pressure. T h e lower t e m p e r a t u r e lessens t h e a t t a c k of t h e lignin. T h e liquor is drawn off a n d cooled t o precipitate a certain a m o u n t of emulsified resin a n d rosin soap. T h e filtrate is used in digesting t h e fibrous material a t high s t e a m pressure for pulp. Where turpentine is t h e only product desired, alkali has, in some cases, been added primarily t o disintegrate t h e rosin a n d thereby permit a more nearly complete distillation of t h e volatile Kerr4 has suggested a continuous process for t h e removal of turpentine a n d rosin from wood, t h e turpentine being first distilled with steam a n d t h e rosin being subsequently dissolved in alkaline liquor. PRELIMINARY
EXPERIMENTS
F r o m a shipment of assorted pine waste, the “ b o x face s l a b ” material was selected as being best suited t o a laboratory investigation. This wood was sound a n d clean, a n d very rich a n d uniform in oleoresin content. When reduced t o chips or shavings t h e wood h a d a strong turpentine odor a n d burned freely with a characteristic, smoky flame. Box-face slabs constitute a comparatively expensive a n d restricted source of raw material for commercial supply a n d t h e oleoresin content (30-40 per cent) is higher t h a n t h a t of average lightwood (15-2 j per cent). This material, then, should present perhaps t h e severest conditions U. S. Pat. 817,960, April 17, 1906. * F r e n c h Patents 432,998, Aug. 5 , 1911, a n d 433,424, Aug. 11, 1911, Ger. Pats. 248,275, July 12, 1912, a n d 257,015, Jan. 12, 1913. Hough, U. S. P a t . 903,471. 4 U. S. Pat. 832,863. 1
.
,
Apr.. 1 9 1 4
T H E J O U RA\TAL 0 F I N D I T ST RI 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
for complete extraction of rosin a n d turpentine, b u t t h e yields m u s t be considered a maximum for southern pine waste. Sample slabs were carefully cleaned b y t h e removal of b a r k , rosin “ s c r a p e ” a n d other surface material. Only t h e clean, inside wood was used in t h e investigations. Some of t h e wood was reduced t o large chipst o small chipsabout I in. X 3 / 4 in. X l ’ s in.-some about 2 in. X ’4 in. X 3? in.-and another portion t o t h i n shavings. A number of preliminary extraction experiments were made t o determine t h e action of caustic soda a n d sodium carbonate on t h e wood under various conditions of temperature a n d pressure. I n general, caustic soda seemed t o be t h e more effective reagent for rosin extraction Sodium carbonate gave cleaner eytracts by reason of i t s milder a t t a c k of t h e lignocellulose, b u t penetration of t h e m-ood was i n most cases incomplete. Elevated temperatures a n d pressures facilitated t h e removal of rosin a n d turpentine, b u t occasioned greater a t t a c k of t h e wood itself. Vacuum t r e a t m e n t proved unsatisfactory, due t o slow penetration of t h e alkali into t h e \vood a t t h e lower temperatures a n d t o t h e tendency toward frothing. especially while t u r pentine distillation m a s proceeding most rapidly. T h e size of wood unit proved t o be a highly important factor in extraction of t h e oleoresin. A fine s t a t e of division, reprcsented by t h e shavings, greatly simplified t h e problem of extraction. On t h e other h a n d , t h e production of good paper pulp necessitates t h e preparation of t h e wood in chip form a n d this introduced some complication i n t h e preliminary alkali t r e a t m e n t . T h e brown extracts obtained b y heating t h e resinous wood in dilute caustic solutions consisted main11 of sodium resinate a n d t h e sodium salts of humic acids. Isolation of t h e rosin content of t h e alkali extract was accomplished b y salting out t h e rosin soap with caustic soda. H u m u s itself is soluble in alkaline solution b u t a small p a r t is carried down b y t h e colloidal soap. Sodium resinate is quite soluble in hot alkaline solutions, as well as in neutral or faintly alkaline solutions i n t h e cold, b u t is only slightly soluble in cold alkaline solutions when t h e concentration of free caustic soda exceeds about 4 per cent. This solubility determines t h e loss in recovery of t h e soap. T h e method has t h e advantage of utilizing t h e same reagent for salting o u t as is employed for extracting t h e wood a n d cooking for pulp. K O acid is necessary for precipitating t h e free rosin, if t h e soap is t o be used as such, a n d no acid-resisting apparatus need be provided. T h e alkali used in extracting t h e wood a n d precipitating t h e soap can be saved partly in t h e form of sodium resinate (thereby enhancing t h e value of t h e rosin fraction), a n d partly in t h e form of brown, supernatant liquor t o be used as a source of alkali for t h e soda cook of t h e extracted chips. After t h e pulping operation, t h e alkali can be recovered in the usual way b y evaporating, incineration a n d causticizing t h e waste soda liquor. As regards actual manipulation, it was found best t o add t h e excess of caustic soda t o t h e hot extract, so t h a t precipitation of t h e soap took place rather
291
slowly as t h e solution cooled down. Very strong IO per cent NaOH-gave somewhat alkali-above syrupy solutions, with increased contamination of t h e soap b y h u m u s a n d without appreciable gain in t h e quantity of soap precipitated. T h e soap precipitate proved difficult t o filter a n d v,Tas separated b y draining or syphoning. With this procedure t h e soft precipitate retained a n appreciable quantity of liquor. T h e bulk of t h e humus was removed from t h e soap b y dissolving t h e samc in t h e minimum amount of hot water a n d salting out again with caustic soda.
I
6
I
I
I-;i
!on:er;ra+ior’of
i ,
NFoH
I
[
I“
i‘
O +
~
FIG.I-SALTISG
i
OCT CCRVE
S O L U B I L I T S OF R O S I S 4 s SODILTX R E S I S A T E I S K a O H S O L U T I O S S A T
20-23’
C.
T o determine t h e power of caustic soda in salting out rosin soap. a series of experiments vias carried o u t with pure rosin on a quantitative scale. T h e results are summarized in Fig. I . P R A C T I C A L E X P E RI 11 E K T S
Experiments were undertaken on a larger scale t o approach more closely t h e conditions in actual commercial operation. The wood was prepared in t h e f o r m of chips of t h e ordinary pulping size, then subjected t o a mild preliminary steaming in dilute alkali t o recover t h e rosin a n d turpentine, a n d finally cooked in stronger alkali in t h e usual way for pulp. The preliminary extraction m-as studied to determine t h e conditions for complete solution of t h e rosin a n d simultaneous distillation of t h e turpentine. T h e draining of t h e alkali extract from t h e chips a n d t h e salting o u t of t h e rosin soap by subsequent addition of excess caustic soda were carried out with conservation of alkali in mind, as me11 as high recovery of rosin soap. The second stage of t h e process-the production of pulp from t h e extracted chips--was carried through t o note a n y possible deleterious effect of t h e preliminary steaming on t h e quality or yield of t h e final pulp. T h e experiments were designed t o throw light on t h e problem of commercial feasibility. T h e wood studied was limited t o box-face slab material, reduced t o chips b y sawing into short lengths a n d splitting t o a n average size of about 1 l / 8 in. X 3/’4 in. X 3/32 in. These chips were considerably longer t h a n t h e smallest commercial size a n d , as penetration of wood proceeds most readily along t h e grain, t h e conditions for alkali extraction were certainly as severe as industrial practice would necessitate. The main supply of chips was thoroughly mixed a n d representative samples obtained for analysis b y quarter-
292
T H E J O C R N A L OF I N D U S T R I A L A N D ENGINFERING C H E M I S T R Y
ing a n d subdividing. T h e chips were stored in stoppered jars t o prevent loss of turpentine, while t h e samples were used t o determine t h e composition of t h e wood. ANALYSIS
O F THE CHIPS
T h e rosin content mas determined b y extracting g r a m portions of t h e very fine chips with ether i n a Soxhlet. On drying t h e chips a t I o j o C. after extraction with ether, a figure was obtained representing t h e percentage of “ a c t u a l wood”-free from moisture, turpentine a n d rosin. This value has been used in computing t h e t r u e pulp yields. T h e percentage of volatile oils could not be accurately determined on a small scale, so t h e highest yield obtained in t h e subseq u e n t steaming experiments has been t a k e n as a close approximation of t h e t r u e “ t u r p e n t i n e ” content of t h e wood. I n Expts. j a n d 6, Ijoo grams of wood yielded 14; cc. of “ t u r p s ” weighing approximately 126 grams on t h e basis of 0.87 specific gravity. This shows t h a t t h e wood contained close t o 8.4 per cent by weight of turpentine a n d pine oil. T h e average composition of t h e m-ood supply was found t o be a s follows: 2j
Vol. 6, No. 4
Agitation was carried on continuously or intermittently t o prevent local overheating a n d t o facilitate solution of t h e rosin. Continuous stirring tended t o f r a y t h e chips a n d render t h e m less suitable for pulping. T h e turpentine fractions were in most cases isolated every fifteen minutes during t h e relieving period. Figs. 2 a n d 3 sho\T t h e r a t e of evolution of t h e volatile oils a n d t h e changes in refractive index a n d specific grai-ity during t h e course of distillation. After t h e
Percentages “Actual wood”. . . . . . . . . . . . . . . . . . . . . . . . . . . . 54.3 Rosin, . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32.1 8.4 Volatile oils. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Moisture, by difference.. . . . . . . . . . . . . . . . . . . . . 5.2
__
100.0
T h u s , t h e total oleoresin a m o u n t e d t o 40.5 per cent, made u p of 7 9 . 2 per cent rosin a n d 20.8 per cent volatile oils. A P PA R A T C S
T h e digester used in carrying o u t t h e extraction a n d cooking of t h e wood was made from a n extraheavy cast iron tee, 6 in. X 6 in. X 4 in. T h e a p p a r a t u s was supported in a horizontal position b y resting t h e flanges i n t w o concrete yokes. T h e 4 in. outlet of t h e t e e was t u r n e d upward t o a c t as a dome for t h e collection of s t e a m a n d turpentine vapor; t h i s a r m was also used for charging a n d discharging. T h e digester was equipped with thermometer pocket, pressure gage a n d relief line, controlled b y a needle valve a n d leading t o a glass condenser. An internal stirring device, consisting of a small shaft fitted with arms, allowed mixing of t h e contents of t h e digester when desired. As condensation was too great when t h e digester was heated b y live s t e a m , heat was furnished b y t w o gas burners. T h e manipulation was much t h e ,same in all t h e experiments. For t h e preliminary extraction, from one t o t w o kilograms of resinous chips mere placed in t h e digester a n d covered with a measured volume of alkaline liquor, containing t h e desired a m o u n t of S a O H o r N a 2 C 0 3 . Space h a d t o be left for steam collection on account of t h e tendency toward foaming. T h e t o p flange was t h e n securely bolted in place, all necessary connections were made a n d t h e burners started. I n a b o u t a n hour t h e relief line was opened t o permit s t e a m distillation of t h e volatile oils. T h e burners were controlled t o maintain a fixed, low pressure (between I j a n d 30 pounds) for extraction of -the rosin.
FIG.
RATE
DISTIL~ATIOS DURISG STEAMISG
OF C R U D E T U R P E h T I N E
PRELIMINARY
preliminary t r e a t m e n t n o longer yielded turpentine in measurable amounts, t h e burners were removed a n d t h e pressure diminished. T h e digester was t h e n inverted by rotating in its seat a n d t h e h o t liquor drained through t h e relief line. T h e “direct e x t r a c t ” was d a r k brown in color a n d t h e rosin was in perfect solution. For analytical purposes t h e liquor was aliquoted, which presented some difficulties. T h e liquor h a d t o be k e p t h o t t o prevent precipitation of t h e rosin soap a n d t h e syrupy solution was n o t easy t o handle. Some of t h e aliquot portions were strengthened, while h o t , with additional caustic soda t o make t h e precipitation of resinate more nearly complete. On cooling, t h e direct extract gave bulky precipitates of fairly white rosin soap. T h e dark supernatant liquors were decanted, drained through cotton or filter paper a n d analyzed for unprecipitated rosin. T h e soap, more or less cont a m i n a t e d with h u m u s a n d liquor, was dissolved in water a n d t h e rosin determined in t h e usual way. T h e chips retained from I t o 1.j times their weight of liquor a f t e r draining. This represents a serious loss of rosin. In order t o recover most of this soap, t h e chips were washed b y covering with hot water a n d boiling for some time. T h e “first wash liquor” was drained as before, cooled a n d aliquoted for determination of rosin content. T h e color of t h e solution was d a r k brown. S o soap precipitated on cooling, al-
Apr.. 1914
4 -I’D E S G I -VE E RI Y G C H E M I S T R Y
T H E J O C R N A L OF INDl’STRIAL
where preliminary extraction of t h e rosin h a d been incomplete. -At t h e end of t h e cook, t h e pressure was drawn down, t h e hot liquor drained off a n d t h e pulp washed thoroughly. T o determine t h e yield, t h e pulp was pressed b y h a n d , carefully sampled, a n d t h e aliquot portion dried a t 1 0 j O C. The pulp wv3s refined in a small beater. samples being taken a t intervals a n d made into sheets on a h a n d frame. Table I contains most of t h e important d a t a bearing on t h e preliminary extractions. T h e rosin determinations have been reserved for later discussion. (See Table 11) I n computing turpentine yield, a factor was worked out for t h e transformation of volume in cubic centimeters t o gallons per cord. A yield of I cc:. from I O O grams of T T O O C ~ is equivalent t o a production of 4000 +- ( I O O X 5.33 j) = 4.8 gallons from a cord of 4000 pounds. The wood used probably weighed considerably more t h a n 4000 pounds per cord, b u t this figure has been chosen as a conservative estimate for rich pine.
though about go per cent could be precipitated b y caustic soda. T o further clean t h e chips enough t o allow sampling a n d careful examination. the wood w a s washed a second time b y boiling 7%-ithfresh water. This “second wash liquor” contained b u t little rosin. In actual practice t h e chips would be ready for t h e introduction of pulping liquor after draining t h e first \\?ash liquor from t h e digester. The extracted chips after mashing as above m-ere discharged fro? t h e digester a n d allowed t o dry somewhat. T h e chips had been appreciably softened b y t h e alkali a n d darkened b y partial attack of t h e lignin. h f t e r thorough mixing, t h e weight mas taken a n d t h e mixture sampled. T h e sample w a s reduced t o small chips and boiled with successive portions of water t o remove t h e last traces of sodium resinate. This final washing yielded small amounts of rosin soap. T h e chips were t h e n dried in t h e oven a n d extracted with ether t o determine t h e percentage of unsaponified rosin left in t h e x o o d . This indicated t h e efficiency of t h e alkali extraction. TABLEI-PRELIMINARY
.~LK.ALI
EXTRXTIOS OF RESINOCSCHIPS
.
