SLASH PINE OLEORESIN J. ALFRED HALL Forest Products Laboratory, Madison, Wis.
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XDUSTRIAL chemists who work with The oleoresin of slash pine is mostly resin acids and biological products are usually familiar terpenes, but the small amounts of other materials are with the variability cf such materials important in technology. The resenes, esters, water, and and the difficulties of adequate standardizawater-soluble substances are normal components of the tion thereby introduced into processes. The original secretion. A preliminary exploration of the waternatural resins are no exception to the general rule that biological products are rarely soluble substances in commercial gum showed their great simple in their composition and often concomplexity and susceptibility to oxidation and thermal tain small quantities of substances that are of decomposition but resulted in no positive identifications. great importance in the production of refined The most important bodies, delicate carbohydrate comand standardized industrial goods. plexes including resinous acids in their structure, are I n a previous publication ( 3 ) the importance in rosin manufacture of the removal of present in much greater quantity than could have been the water-soluble portion of the crude gum derived from bark. Clean, uniform gum rosin is a comwas emphasized, and a brief description given mercial prospect in the near future when refining methods of the gross properties of the water-soluble now being developed are adopted. materials. It was pointed out that these complex substances were converted during the distillation process to very dark bodies bark t o facilitate the flow of oleoresin into the bottle. From and should be removed in aqueous solution prior to distillathis hole two others 0.5 inch (1.27 cm.) in diameter and 6 tion in order to obtain the lightest colored rosins possible. inches (15.2 cm.) long were branched tangentially into the tree, Their susceptibility to oxidation was also discussed. running as close to the outer sapwood as possible. The bottle was then inserted and sealed in with modeling clay. The whole A recent article by Smith (6) affords excellent confirmation operation took less than 5 minutes per bottle. Two trees were of these points. Smith states that the process used by him, tapped. washing the diluted gum twice with a n equal volume of water Tree 1 was a large slash pine about 30 inches (76 cm.) in diamea t about 95' C., removes water which contains dissolved ter. It bore three old scars on three quadrants. Eight bottles were hung on the fourth quadrant at various short distances solids. KO clean-cut analytical distinction can be made befrom the ground. The average yield per bottle during the coltween water-soluble materials naturally present and those lecting period was about 35 grams. from extraneous sources when dealing with commercial oleoTree 2 was about a 14-inch (36-em.) slash pine bearing one resin. However, a rough qualitative separation as regards abandoned face. Four bottles were attached on the round portion of the trunk near the ground. These bottles contained an averorigin does appear in the present paper. The distinction age of about 200 grams of gum per bottle at the end of the colmight seem to be a mere quibble but is really significant belecting period. cause the important question of the excretion of water-soluble The bottles were attached t o the trees from 3:00 P. M. May 24 materials along with the oleoresin hinges upon that point. to 8 : O O .4. M. May 26, 1934. Then they were removed, tightly corked, and mailed to the Forest Products Laboratory. Upon Examination of Clean Oleoresin their arrival May 29, the oleoresin in all bottles was still clear and free from any crystallization. They were placed in storage at Since the examination of commercial gum offered no oppor4" C. until they could be analyzed. tunity of clear-cut analytical distinction between extraneous Up to August, 1934, samples removed from the ice box and water-soluble material and such material normally present in allowed to come to room temperature showed little or no crysclean gum, oleoresin was collected in a manner designed to tallization. At the present time (January, 1937) one remainDrevent effectivelv the inclusion Qf anything but the wound Lng b o t t l e s h o w s secretion. The very little crystallizacollection was carried tion while the other out by T. A. Liefeld OF CLEAN OLEORESIN TABLE I. AKALYSIS shows normal crysof the Lake City, Saponi- Turpen- WaterUntallization (Figure 1). Fla., branch of the ficatine Sol. saponiSource pE Acid tion ConMateRosin fiable No explanation Southern Forest ExOleoresin N0.Q N0.a tent* rialb YieldC Waterd Mattere Loss! i s o f f e r e d for this periment Station : % by weight of original oleoresinp e c u l i a r behavior Tree 1 125.8 13s 21.9 0.04 76.3 0.3 9.85 1.46 The gum was colTree 2 128 138 22.7 0,035 76.69 0.3 7.02 0.28 which is so much lectedin 250-cc. bottles a Determin ed in the usual way. more s t r i k i n g than t h a t w e r e 7 inches in..t,he the The b The watei pollect,ins _______.. ...- flak dnrine --.. ~~.~ turnentine determination was saved. t of 70" to 80' C., and.the ..~ .~ .~~~ . wet rosin in the flask was taken up in petroleum-wiix~a hoilinz~noin usual with n o r m a l (17.8 cm.) long, with solution was thoroughly washed with distilled w.ater. The aqueow solutions were united necks 1 inch (2.5 cm.) oleoresin. It serves and evaporated to dryness on the steam bath, finwuug wciic! ht at 105' C. long and about 1 inch The petroleum solution from b gave rosin upon evaporation and d kying in an oil bath to emphasize again at 175' C . for 1 hour in diameter. A hole the v a r i a b i l i t y of d Water was determined by distilling the oleoresin with toluene in a Bidwell-Sterling apjust large enough for paratus this biological prodthe neck of the bottle e Unia onifiable matter(resene) was determined in the toluene solution from d by saponifying wit{ alcoholic potassium hydroxide, evaporating in a steam bath, taking up in water, to be snugly inserted uct. The a n a l y s e s in a continuous extractor with ether. The ether extract and extracting the soap solution was bored about 1 inch was then distilled nith steam untll nothing more came over. The nonvolatile residue was shown in Table I were into the tree t r u n k taken up in ether, evaporated, and dried at 150° C. completed in August, f Loss = weight of oleoresin (turpentine + rosin + rVater + water-soluble materid). and s 1o p i n g slightly 1934. downward toward the
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L V UUIIJLI~LIII
JUNE, 1937
IXDUSTIIIAL AND ENGINEERING CHEMISTRY
very sensitive phenol was also obtained. This product resinified quickly and could not be identified. It must be emphasized that, although this complex body evidently contained a phenol in its molecule, as indicated by ferric chloride and bromine reactions, its chemical conduct bore no resemblance to that of the tannins from slash pine phloem or inner bark. This laboratory has examined these tannins intensi\rely. They are phlohatannins vhicli yield only to drastic fusion with potassinm hydroxide, and then only protocatecliuic acid, catechol, and phloroglucinol are obtained in extremely small yields. These substances were uot obtained from A nor were its physical appearance, solubilities, eeneral chemical conduct similar to those of the tannins and ,~ from phloem. The lead acetate urecinitate B was decomnosed with hvdrogen sulfide after snipension in water contaiiiing a 1itt.k acetic acid. The filtrate from the lead sulfide was brown and continued to darken at the surface while depositing an alwliolsoluhlc gum. In order to stahilizc the solution, air was hubbled through it for 12 hours. The blackish hrovn guininy precipitate was removed arid found to weigh about 10 grams pel: 5 gallons of concentrated extract. It mas an indefinite mixture but contained nitrogen. After removal of the gurriniy precipitate, the solution was extracted with ether. This extract contained an acid of oily nature. Tile extracted solntion resiionded pnsitively to the Molisch carhahydrate test and reduced Fehling solution. Xo phenols could he obtained from this conip1t:x and very unstable material. The load acetate yrecipitatc H appeared to be rclnted to .A but was apparently in a less stable form. PrccipiLat,e C, ohtained by making a,lkalinc the filt.rate irnni R, lvas decomposcd by incans of liydrogeii sulfirlc. After complete reinoval of hydrogen sulfide, the filtrate fr(,rn the lead sulfide gave a strong Moliscli reaction, raliidly reduced Fcliliug solnt,inn iri tlie cold, arid reduced neutral potassium p~rnianganateinst,antaoeoiislg. T h e solution gave definite orange color to sodium nitroprusside. It immediately precipitated a golden yellow derivat.iue when treated with phen>,Ihydrazine hydrochloride and sodinin acetate at rnom temperatore. This derivative liad an indefinite melting point annrnd I to 160" C. It could not he crystallized. Several substituted phenylliydramine derivatives behaved similarly. I n the ordinary orciiiol and resorcinol tests for pentoses and uronic acids, only I-irownisli orange colors were ohtained, which are unlike those iron1 the known compounds. The free substance or suhstances contained in thk solut,ion were obtained by careful evaporation i n U ~ C U and O with carbon dioxide atmospheres as sirups only, hut in quantities of several grams. These sirups irere very unstable. Similar sirups have heen obtained in extremely niinute quantities from the hydrolysis of certain glycosides isolated from large quantities of the phloem of slash pine. It is not conceivable that even a minor fraction of the amounts ohtained in this investigation could have arisen from the sniall amounts of hark contained in the crude gum. Further, 50 grams of the crude pliloein ta.nnins givc a reducing power ifter acid hydrolysis equivalent to only 0.8 gram of glucose. Therefore, the amounts of sugars present could not possibly have arisen from tannin hydrolysis. Filtrate n,wliich was the main solution after tlie removal of precipitate A and lead precipitates R and C, n.as freed from lead by nieans ai hydrogen snlkle. The 6ltra.te from lead sulfide n.as a light yellow solution. It cont.ained consiilcra.hlc furtlisr quantities of carbohydrate materials obtainablo only as sirups. Particularly irniiortant was the presence in small qmntities of n substanw that v a s extracted from t i c w,qiieoiis srilution Iiy means of ether. I h r ing the course of the whole examinat.ion this substance was obtained many times, nsnally in quantities corresponding to
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about 1 gram in each 5 gallons of concentrated washings. Repeated attempts to cryetallize it arid its derivatives failed. This substance was obviously a glycoside. It hydrolysed quickly to give a volatile oil, a resinous acid, and a carbohydrate sirup with the same react,ions as C. In the earlier stages of tliis investigation, alien the material mas st.ill fresh, several grams of this glycoside were ihtained. As the material aged, however, the yield grew less until it finally became entirely unavailable. This was undoubtedly dne to hydrolyris and leads to the suspiciom t,hat the sirups from C were originally present in glycosidic combination,
Discussion This greatly condensed account of a very coinplicated and uiisatisfacbory investigation may be regarded as describing a preliminary exploration. A satisfactory investigation of the nature of the bodies deserihed will require much more careful preparatiou. of mat.erial, for the substances are extremely delicate. It is important to recognize that in this examination of a coniiimcial oleoresin iio bodies were encountered that bore a remote resemblance to the tannins of tlie phloem. It is also important that in the intensive examination of the phloem carried out. in tliis Iahoratory, no substances comparable to those described were ohtained, with tho exception of the small yields frnm the phloeni of sirrilar glycoside and carhahydrate fractions. The tannins of the phloem are readily soluble in vater, aid it is entirely conceivable that they may contribute to the water-solnhle content of some commercial gum; but if the subitancca dcscribed arise from bark, i t is an inescapable comclusion that, large quantities of phlocm tannins should also hc prcsent. Large anioiints nf ordinary glucose and sucrose are found iri tho phloem hut riot in the olewesin. The inference is clear that the suhstaiices described form a part of tlie Iiiological secretion, oleoresiri. A clear recognition of this fact on the part of the n a r d stores industry and tho adoption of ineaiis now being developed by the Bureau of Chemistry aiid Soils for their removal will uiidoubtcdly iniprove the clcanliness and color of commercial rosin. It has already been dcrnonstrated coinmcrcially that oleoresin froin which part of the mater-mluble content is removed by incomplete washing produces lighter colored soaps than those obtained Erotn tlie unwaslied guni. Undoohtedly a t,linroughly clean guni rosin is a prospcct iif the mar future.
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Literature Cited (1) BalaS, F., Caaopi,is Ceskoslou. LLkriinicl~n, 7 , 320-38 (19271; Chem. Abs., 23. 1644 (19291. (2) Black, A. P., arid Thronson, S.M., INU, EXO.CHLM.. 26. 6 6 9 (1934).
(3) Hell, J. A., Ibzd., 24, 1247-0 (1932). (41 Otto. 13. J. H., thesis, Uniu. of Fh.,1930. ( 5 ) Smith, W. C.,1x0. E m . CHEM.28, 408-13 (1936) Rec~rvmoJanuary 16. 1937
