45 4 INDUSTRIAL A N D ENGINEERING CHEMISTRY Vol. 38, N o. 4 acids occur s a t t,he outer region and increases as it approachcs the is crease in resin acid is noted, but whether the inner or outer heart- wood has th e larger or smaller percentage of resin acids is dc- pendent upon their respective cxtractivc contents. This constituent iiicreases in per (wit as it passes from the newly formed sapwood to the inner sapwood where it reaches a maximum; then the percentage of f att y aci ds decreases as it approachc s the pith. This fraction usually iiicreases in per cent as it approaches the pi th o f t he tree. I n hea rtwood th e percentag e of ester s decrens es froni t,he outer hear twood to the pith. In some instances the per- centage continues to increase as it approachcs the out ,er sapwood; in others it ten ds to decrease. UXSAPONIFIABLES. n general, t h e perccntage of unsaponifiable is the leas t a t the outer sapwoo d and iiicreases , in some < maximum in the outer heartwood and then decreases as it nil- proaches the center of the trce. I t is interesting to note that t he coniposit.ion o f thc outrr niitltl l(~ hear,tnood in stand I1 1 indicates that it is apparently in the trail- sition stage from sapwood t o heartwood. The relatively lo\\- rwin acid content, together w it hi he slight increase i n unsaponifi- able material in this outer heartwood region, suggests that this transitional deposition of extractives was t,aking place. FREE ATTY CIDS. VOLATILES. ESTERS. APPLICATION OF RESULTS I11 seeking means for effectivel y utilizing th e potentia l c.lieriiicw1 products from ponderosa pine, it was found that this wood coii- tained a sufficient quantity of extractives to warrant t he possib le removal and recovery of these materials from the lumber and from forest and mill wood waste. Preliminary investigation\ have shown th at it is possib le t o extract all or a large portion 01 the extractives fro m lumber; the result is 8 furt her improv eiiicn t in the lumber of fered by manufacturers; in addition, a com- mercial volume of extractive products may become available from this wood. Th e amount of recoverable extractables is not uniformly distributed throughout the trunk of the tree. The average extracti ve cont ent in sapwood is u sually within tlie limit . 2. 0 to 9.8%.of th e weight of the dry wood, whilc th e heartwood extractables are usually within the limits 3 .5 t o 31.5% of tho weight of the dry wood. Tho greater quantities o f extractivc i are obtain ed from the lumbci antl wood waste originating from the but t portion o f th e trunk and from tha t portion of the trcl containing massed pitch arcs?. The acetone extractives, R Iictlier from the heartwood or \ u p wood, contain, in addition to rebin acids and terpenes, free fatly acids , fats, and unsaponi fiablc msteiial. Thus the extractive. differ from gum oleoresin foiIncd by wounding the tree by bhe presence of these aliphatic and un5aponifiable substances. Th e percentage of each o f thesc erilitics is not uniformly distributed throughout the tree but depcntls from which part of the log thc. extrac tives arc obtained. In tlic case o f heartwood extrac tive<, the products found in approxiinaic or der o f quanti ty preicnt ar e resin acids, free fatty acids, unLaponifiable, esters, volatile, wntri soluble, and w ater and ether insoluble. In sapwood extractive. these entitios are found in thc following older: free fat ty acidi, r e h acids, water soluble, estcrs, uninponifiable, mater and et h 6.r iiisolu ble, an d volstile. Since th r con imercial value o f t h e x- tractives is contingent in part upon th e quantity and exact r i i tule of its entities, t he identifi cdtion o f ~xc*ki f thesc produvt iindo1 inviLhtig atiori by thi - lahlr i(orr ACK \ 0 % J,LI)( ;Rf EN1 The author is indebted to Gcorgc Schroeder and C. V. Zaayeu for collecting the wood sections antl t h e advice o f Al bert H c rrn ~ n ~ I > greatly appreciated. LITEHA7'UL{ 1 . : c;t'rl?;l) (1 ) Adariis, J . INU. NO . Cmx., 7 , 957 (1913), ( 2 ) A4nderson, bid., 36 , 662-3 (1944). ( 3 ) Assoc . o f Officia l Agr. Chein., Methods of Analysis, p p. 469-71 141 Benson and Jones. .J. ISD. $hi;. HEM.. . 1096 (191'7i (1940). , , Dore, It~id., 1, 556-63 (1919). (6) Hihbert and Phillips, Can. J. licssnrch, 4 , 1-34 (1931) (7) Koch an d Kricg, Chem.-ZtN., 15, 140-1 (1938). (8) Kiajriiiovic, Ibid., 55, 894 (1931). (9) Kurth, IXD. NG. HEM., 3, 1156 (1931). (10) Schorger, U. S. Forest Service, Bull. 119 (1913). (11) Trendelertburg and Schailc, Papier-Fnhr., 35, 221-30 (1937). (12) Tiertelak and Garbaczowiia, lsn. RSG. CHBM., NAL. ED., a , (13) JTise, "Wood Chemistry", pp . Xi3-4, A.C.S. Monograph 87 (14) \TOM an d Scholae, Chern,-Zlg., 38, 3G!)-70 (1914). 110-11 (1935). - Ne w York, Reinhold Pub. Gorp., 1944. issociation Pressure o f Ammonium C a r k . P . EG-kN, JR., J. E. POTI'S, JR., AND GEQRGETTE 1). POn'S Tennessee Valley Authority, Wilson Dum, Ala. EMPERATURE-pressure relations for th e di ssoci ation o f T olid ammonium carbamate into gaseo us ammonia and (1-5). The reported values are divcrgeiit; at a total pressure of 4 0 atmospheres the diver gence is as much as 17 atmospheres. The present paper cover5 .t st udy o f the dissociati on preism c of sol id ammonium carbamate over the temperature range 35' $0 83' C . and in the absence of 'til excess o f ei the r gaseous rea ctv nf From the vapor pressure data tlie lree energy of dissociatioii and th e heat o f dissociation h a w bwn derived. Briggs and Migrdichian (1)- measured the dissociation pressure of ammonium carbamate over temperature range 10" to 49" C. PREPARATION OF SOLID A3tMOh'IUR.I CARBAMATE and obtained very consistent data. They also studied the effect o f excess ammo nia or carbon dioxide a nd found excellent agreement mith the mass Ian accoiding to the equation: Solid ammonium carbam i te ~vns repared directly in a 50-c sample bulb (Figure 1) which later was connected to the pre?siirci measuring system. Stoichio metric proportioning o f th e r('ii< tant s, as was employed by Briggs and Migrdichian (f), proved ta br unnecessary. Thc carbamatc na s deposited in the bul b fron, II&OZ1\"2 (solid) = BTH, gas) + COz (gas) (1 )
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454 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 Vol. 38, No. 4acids occurs a t t,he outer region and increases as it approachcs th e
heartwood. When the heartwood is reached, a material in-
crease in resin acid is noted, but whether the inner or outer heart-
wood has the larger or smaller percentage of resin acids is dc-
pendent upon their respective cxtractivc contents.
This constituent iiicreases in per (wit as
it passes from the newly formed sapwood to the inner sapwood
where it reaches a maximum; then the percentage of f att y acids
decreases as it approachcs the pith.This fraction usually iiicreases in per cent as it
approaches the pi th of the tree.
In heartwood th e percentage of esters decrenses f roni
t,he outer heartwood to the pith. I n some instances t he per-
centage continues t o increase as it approachcs the out,ersapwood;
in others it ten ds to decrease.
UXSAPONIFIABLES.n general, the perccntage of unsaponifiable
is the leas t a t the outer sapwood and iiicreases, in some <maximum in the outer heartwood and then decreases as it ni l -
proaches the center of t he trce.
I t is interesting to note tha t t he coniposit.ion of thc outrr niitltll(~
hear,tnood in stan d I11 indicates that it is apparently in the trail-
sition stage from sapwood to heartwood. The relatively lo\\-
rwin acid content, together w it hi he slight increase in unsaponifi-
able material in this outer heartwood region, suggests that this
transitional deposition of extrac tives was t,aking place.
FREE ATTYCIDS.
VOLATILES.
ESTERS.
APPLICATION OF RESULTS
I11seeking means for effectively utilizing the potentia l c.lieriiicw1
products from ponderosa pine, it was found that this wood coii-
tained a sufficient quan tit y of extractives to warrant t he possible
removal and recovery of these materials from the lumber and
from forest and mill wood waste. Preliminary investigation\
have shown th at it is possible t o extract all or a large portion 01
the extractives from lumber; the result is 8 further improveiiicnt
in the lumber offered by manufacturers; in addition, a com-
mercial volume of extractive products may become available
from this wood. Th e amount of recoverable extrac tables is not
uniformly distributed throughout the trunk of the tree. The
average extractive content in sapwood is usually within tlie limit.
2.0 to 9.8%.of the weight of the dry wood, whilc th e heartwood
extractables are usually within the limits 3 .5 to 31.5% of tho
weight of the dry wood. Tho greater quantities of extractivc i
are obtained from the lumbci antl wood waste originating from
the but t portion of th e trunk and from tha t portion of th e trcl
containing massed pitch arcs?.
The acetone extractives, R Iictlier from the heartwood or \ u p
wood, contain, in addition to rebin acids and terpenes, free fatly
acids, fats, and unsaponifiablc msteiia l. Thus the extractive.
differ from gum oleoresin foiIncd by wounding the tree by bhe
presence of these aliphatic and un5aponifiable substances. T h e
percentage of each of thesc erilitics is not uniformly dis tributedthroughout the tree but depcntls from which part of the log thc.
extrac tives arc obtained. In tlic case of heartwood extrac tive<,
the products found in approxiinaic order of quanti ty preicnt are
soluble, and water and ether insoluble. In sapwood extractive.
these entitios are found in thc following older: free fat ty acidi,
r e h acids, water soluble, estcrs, uninponifiable, mater an d eth6.r
iiisoluble, and volstile. Since th r conimercial value of t h e x-
tractives is contingent in part upon th e quantity and exact r i i
tule of its entities, t he identificdtion o f ~x c*k if thesc produvt
iindo1 inviLhtigatiori by thi- l a h l r i ( o r r
ACK\0% J,LI)( ;Rf E N 1
The author is indebted to Gcorgc Schroeder and C. V. Zaayeu
for collecting the wood sections ant l t h e advice of Albert H c r r n ~ nI > greatly appreciated.
LITEHA7'UL{ 1.: c;t'rl?;l)
(1 ) Adariis, J . INU. NO.C m x . , 7, 957 (1913),( 2 ) A4nderson, b i d . , 3 6 , 662-3 (1944).
( 3 ) Assoc. of Official Agr. Chein . , Methods of Analysis, pp. 469-71
141 Benson and Jones. .J. ISD. $hi;.HEM.. . 1096 (191'7i
(1940).
, ,
Dore, I t ~ i d . , 1, 556-63 (1919).
(6) Hihbert and Phillips, C a n . J . l i c s s n r c h , 4 , 1-34 (1931)(7) Koch an d Kricg, Chem.-ZtN., 15, 1 4 0 - 1 (1938).
(8)Kiajriiiovic, I b i d . , 55, 894 (1931).
(9) Kurth, IXD. NG. HEM. , 3, 1156 (1931).
(10) Schorger, U. S. Forest Service, Bull. 119 (1913).(11) Trendelertburg and Schailc, P a p ie r - F n h r . , 35, 221-30 (1937).(12) Tiertelak and Garbaczowiia, lsn. RSG. CHBM., NAL.ED., a ,