I N D U S T R I A L A N D ENGINEERING CHEMISTRY
1156
Vol. 23, No. 10
Distribution of Ether Extractive in Slash Pine' E. F. Kurth* and E. C. Sherrard3 FOREST PRODUCTS LABORATORY, MADISON. WIS.
The extractive in young slash pine trees that appear been generally reported ( 2 , 1 1 , to contain only sapwood is not uniformly distributed for its primary object 12, 14). Owing to the many throughout the trunk. Some sections of the trunk a determination of the methods used by these invesrun very high in material of an oleoresinous nature, resin distribution in the saptigators, no definite concluwhereas other sections run relatively low in this mawood of turpentined and unsions can be drawn regarding terial. The distribution of the extractive in all the trees turpentined slash pine, Pinus the effect of seasoning on studied, however, follows certain definite rules. caribaea M o r e l e t . Slash the solubility of the extracThe separation and characterization of the conpine is of special i n t e r e s t tives. The s u b s t a n c e s exstituents composing sapwood extractive is a long procbecause it is an important tracted are of such chemical ess. It can, however, be definitely stated from the res o u r c e of naval stores and nature that they are very sults of this investigation that the extractive contained is becoming of increasing insusceptible to the action of in the sapwood differs in character from that conterest to the pulp and paper light, heat, air, and chemical tained in heartwood or from the gum oleoresin formed industry. reagents. by wounding the tree. The difference between the sapThe distribution and comwood extractive and the heartwood extractive may be position of the extractives in Description of Stands caused by a greater dilution of the resin acids in the young conifers have not been sapwood by esters than in the heartwood. Similarly, The slash pine used for this thoroughly studied. I n fact, gum oleoresin may differ from both heartwood and sapstudy was collected from four in many instances no distincwood extractive by the presence of a larger portion of separate stands by B. H. Paul,, tion has even been made beesters and unsaponifiable material in the latter two. silviculturist, F o r e s t Prodt w e e n sapwood and heartThe composition of the extractive in the sapwood of ucts Laboratory. Stands 1 wood extractives, a l t h o u g h slash pine cannot be regarded as uniform, but is and 4 are on low, moist sites. the resin content of sapwood transitional, changing with the age of the wood. This Stands 2 and 3 are on areas is very much less than that of is further demonstrated by a preliminary investigation having a somewhat higher heartwood. of the unsaponifiable portion of the ether extracts, elevation than is common for G o m b e r g (6) has deterwhich reveals that the outer rings of the sapwood conslash pine. mined the amount. of ethertain appreciably larger quantities of sterols. Stand 1, which is near Cogsoluble material in turpendell, Ga., consists principally tined and untumentined trees of longleaf pine containing a large proportion of heartwood. of young slash pine trees of rapid growth, ranging from 8 The ether extractive present in certain specimens of maritime to 18 years of age. The trees are distributed irregularly pine has also been investigated (4, IS). Filipovich and over the area and have large spreading crowns. The diameVuisotzkii (5) state that the resin of Pinus silvestris varies in ters of the trees range up to 10 inches, breast high. Stand 2 is on old pasture land near Waresboro, Ga. The composition according to the season and to the height in the tree, the amount of unsaponifiable material increasing with forest land is about as high as the surrounding cultivated height from 7.34 per cent a t the level of the ground to 9.7 fields but it is not far distant from a typical slash pine-cypress swamp. The trees logged from this stand were young and per cent at a height of 8.34 meters. The most satisfactory method of obtaining the crude resin thrifty, and were rather openly spaced. They varied in age from the wood of the conifers is by extracting it with inert from 16 to 24 years, and in diameter from 8.7 to 11.0 inches, solvents. Ethyl ether, gasoline, and petroleum ether all breast high. yield light-colored extracts. Acetone, methanol, ethyl alcoStand 3, which is also near Waresboro, Ga., is a rather dense hol, and benzene-alcohol mixtures show greater extractive second-growth stand of slash pine growing on an old field. powers. The extract, however, is darker in color and usually This stand borders a small water course which contained turbid. Ethyl ether, being a pure compound and thus hav- practically no water a t the time the trees were cut for this ing a definite boiling point, was the solvent chosen for this study. The trees logged stood about 100 feet from the investigation. It dissolves both hydrocarbons and oxygen- water course on land said never to have been covered by high ated compounds, but very little of the water-soluble con- water. The trees on account of crowding were growing slowly a t the time of cutting The trees ranged in age from 25 to stituents. The ether extractives of the genus Pinus consist primarily 30 years, and in diameter from 7.3 to 8.7 inches, breast high. of resin acids, essential oils, fats and fatty acids, and un- A few loblolly pine trees were scattered throughout the stand. saponifiable or inert matter. They, therefore, differ in comStand 4,which is near Lake City, Fla., is of the cypressposition from the gum oleoresin from longleaf and slash pine slash pine forest type. The stand is rather closely stocked obtained by wounding the tree, which is generally regarded with trees of 30 to 35 years of age. The diameters of the as a solution of resin acids in turpentine. Schorger (9) has trees at breast height range from 2 to 10 inches. reported an analysis of slash pine leaf and twig oil, the comThe color of the wood in the center of the older trees (25position of which differs from that of gum turpentine (3) 35 years) was of a deeper shade than the adjoining wood. and also of crude wood turpentine (8). The contrast in color was noticeable in several instances only A decrease in the resin and fat content with seasoning has after the cut end had been exposed for several days. The 1 Received April 6, 1931. Presented before the Division of Cellulose wood in this area was not in all respects true heartwood, but Chemistry at the Slst Meeting of the American Chemiral Society, Indianappeared to be in the transitional stage from sapwood to apolis, Ind., March 30 to April 3, 1931. heartwood. Figure 1 shows representative specimens of 9 Junior chemist. slash pine. Principal chemist.
T
HIS investigation had
Treatment of Specimens Prior to Extraction The logs, in 9-foot lengths, were moeivd a t the Forc.f, l'roiliiots Laboratory in Sovember, 1930, about 10 days after cut,t,iiig,and were immediately reduced to bolts in lengths of 1 fect. The bolts (generally top, middle, and butt,) selected for this investigation were stored in a yard. Vl'ith the esisting wiuter weather the moisture became frozen, and was generally in this state up to the t.iine the wood was cx-
I%ydrying tho ertrected sawilust ;it 1 0 j o t:., the weight 4rf the i\.ootl srtmple, less moisture, crude resin, and volatile
txact.d. ~
FMure 1-Representaflve Specimens of Slash Yiiie A A-wide -Wide spa& spadng rapid rapid crowtk, growth, large larre propwtion pcopnrtion of 01 summcrnoal sprin~woal spacing, I i O W giowtb
c -close
J w t ilrior to extraction a cross-sectional disk free from kn0t.s \viis taken from the center of each 4-foot bolt. Each disk having a diameter greater than 4 inches was divided into three samples. The first sample contained the outer r i ~ ~ gthe s , second, the intermediate rings, and the third, the center rinas. Fieiire ., 2 illustrat.es the method of samnline. . I The wood samples were then reduced to sawdust on R special saw (20). This operation is rapid, the wood being exposed to the air for only a brief period.
oil, was obtained. This valm was then wed to compute the percentage of ext,ract. \olatile oil determinat,iuns wen: made oii portions of the uriextracted wood sample. The method adopted was similar to the oiie used for determiuing the volatile oil in citrus fruits (l!?).A composite sample of the wood oil pave a specific gravity a t 25' C. of 0.593. Acid and saponification nunilms were deterI mined according to the method of Gri& (7). The unsaponifiable residue was determined by the method of the Association of OfFieial Agricultural Cliemists (1). The size of t.he pith in slasli pine trees varies with the rate of growth. Gsually, it is but a small fraction of the cross-sectional a m . A composite of the piths from several trecs sl~owedan etaher extractive content of 14.6 per cent. Specimens of slash pine extractcd with both ether and petroleum ether, b. p. 40" to 60" C., demonstrated a greater extractive p o m r for the ether. The netroleurn ether extract. as shown in Table I, id 10.9 to 18.2 per cent srnaller than the ether extrar:t. The difference, apparently, i s in the amount of saponifiable m a t e r i a l extracted. ~~
lable I.--RILrgction with Petruleurn Ether (h, p, 481 fo bOF c,, uf Four Sampler of Slash Pine -. AUo S ~ P O N ~UC~A s a-~ o x rD-E C X ~ A S H ~~
SOLVENT ~~~
___
EXTRA=
TlON
". ~h-_ _ _N
~ .
4 " ,"
I
Gthri Petroleum ether Ether Pelioleurnethci Ether Petroieumetbct Ether
Petrolrilm ether
3.30 2.94
7.66
6.40 5.7s 4.83 0 92 5.66
..-
IN
IIABLB
nssmn
EXTBACI
%
4 " ,"
55.8
52.7 45.7 52.1 35.6 37.2 47.5 47.4
..
197.5 193.2 194.5 177.5 260.0 201.0 198.5 184.5
--
l"
8.38 6.30 5 92 5.90 6.08 4.90 5.85 8.0
10.9 16.4 10.4 18.2 ~
Table Il---Ertracfion ot Sese" Samples of Green and Nr-Dry Slash Pi.,,-
A o o No. ~
% Green
Air-dried 2 0 days Green Air-dried 20 dayr Green
Air-dried 20 days Grcm Air-drled 30 days Green Air-dried 35 days Cree" Air-dried 30 days Green Air-dried 30 dam
Pipure 2---Method ot Sempliri&! SIssh Pine for Eafracti""
Crystals of ice were in the sawdust from most of the saiiiples up to the time the wood was covered with solvent. The wood was, therefore, in a green condition with very little opportunity for loss of moisture or volatile oil from the time the tree was cut to the time the wood was extracted. Extraction The extractions were carried out in a battery of Soxhlet extractors fitted with ground-glass connections. Thirty to 60 grams oi the wood were extracted for 8 hours with ctlier of U. S. P. quality. The resulting extract was finally dried to constant weight by heating in an electric oven at 105' C. Occasional rolling of the flask hastened bhe removal of the residual moisture and turpentine.
3.60 3.48 4.76 4.80 2.06 2.09 13.3 14.6 5.00
4.55 1.85 2.15 3.16 3.31
50.1 57.2 a8.2 54.8 44.6 56.7 139.6 139.1 80.0 119.5 74.6 87.0 59.9 63.3
196.3
198.0 196.5 201. 0 196.8 215.0 178.5
Samples of green slash pine sawdust were divided into two parts. One part was extracted in the green condition and the other was extracted after i t had been exposed to tlie air at room temperature for from 20 to 35 days. The results are summarized in Table 11. The difference in solubility between the green and air-dried sawdust, as a rule, i s not large. There is, however, a very noticeable change in the chemical constants. Distribution of Oil and Extractive in Unturpentined Slash Pine
The distribution of oil and extractive as determined for iadiviclual second-growth uiitiirpentined trees is shorn in Table I11 and is summarized for each stand in Table IV. The acid and saponification numbers together with the un-
1158
INDUSTRIAL AND ENGINEERING CHEMISTRY
Vol. 23, No. 10 saponifiable matter for the extracts are also included in the tables. Table V gives data on the extractive present in an old virgin-growth slash pine, and shows the contrast between e x t r a c t i v e present in sapwood and that contained in t r u e heartwood. The sapwood is d e s i g n a t e d by the l e t t e r s and the heartwood by the letter h. The figure which precedes the s designates, for the sapwood, the position of the piece in the cross section counting from the bark; that which precedes the h designates, for the heartwood, the position of the piece counting from the line of division b e t w e e n sapwood and h e a r t w o o d . The saponification values for the heartwood extracts are not included; after heating with alcoholic potassium hydroxide the resulting liquors were too opaque to o b t a i n accurate titrations. Additional data show that the distribution and magnitude of the extractive in turpentined trees from a short d i s t a n c e above the face to the top of the trunk is of the same general order as in unt u r p e n t i n e d trees. In the v i c i n i t y of the face of the turpentined tree the extractive content is irregular, and is influenced by the size and age of the face. The unsaponifiable portion of the ether e x t r a c t i v e from the outer rings of turpentined and unturpentined young slash pine t r e e s c o n s i s t s l a r g e l y of sterols. Phytosterol, m. p. 132' C. (uncorrected), h a s been identified.
I
i
Summary
YOUNG SECOND-GROWTH S L A S H PINE-(^) T h e 3
w
m
F
' m
d
$2 2
rn
z
m
d
m
m
o
4
2
m
La
N
w
m
amount of oil and extractive increased from the bark to the center of the trunk for all the trees studied. (2) I n most t r e e s t h e r e was a decided increase of ext r a c t i v e a t t h e center of the trunk with d e c r e a s e in height in tree. Only a slight i n c r e a s e of extractive was observed a t the outside of the trunk with d e c r e a s e in height in tree.
October, 1931
INDUSTRIAL A N D ENGINEERING CHEMISTRY r
B
mol .*
N
r
EI
(3) The acid number increased with the age of the wood and was highest a t the center of the butt log. (4) The saponification number decreased with the age of the wood, and was lowest a t the center of the butt log. (5) The amount of unsaponifiable matter for the older trees was the largest at the center of the trunk. In general, there was an increase of unsaponifiable matter at the center of the trunk with decrease in height in tree, and a slight increase at the outside of the trunk with increase in height in tree. The amount of unsaponifiable matter appeared to vary with the acid number. Table V-Ether
Extractive from Virgin-Growth Unturpentlned Slash Pine
CROSS-SRCDISK
TIONAL
Height Dinm. above without Sample ground bark
Ff. 40
24
In. 6.5
7.0
8;
lh 2h l1s h 2h 3h 4h
4
se 82 was 00
000
dlmo
I l h 000
n-l
22
1159
11 5
1s
2s lh 2h 3k 4h 5h
, ~
; : :
ETHER ACID EXTRACT No.
SAPONITION
No.
iir 4.21 Trace 4.07 2.30 2 28 3.54 Trace 0.36 0 32 0.48 OS6 1.7 2.2
% 3.51 4.25 32.6 51.6 3.44 30.6 23.2 24.9 42.8 2.31 4.44 4.46 10.68 10.42 16.07 23.95
--
FICA-
FIABLB
7;;%
79.8 96.2 148.0 134.1 71.6 139.5 148 0 144.5 142.5 62.4 58.1 135.5 140.2 145.5 143.5 142.1
196.5 213.0
,.. ,
..
205.0
. .. ... ... ...
155.7 172.5
... ... ... ... ...
14.2 22.2 12.5 14.1 16.9 11.95 11.5 13.05 16.35 22.2 21.2 26.8 23.0 12.15 25.0 17.95
(6) The trees of rapid growth showed a higher extractive content than the trees of slow growth. Of the trees of rapid growth, those having a high proportion of summerwood contained less extractive than those having a high proportion of springwood. (7) The extractive from the outer rings of the trunk was a bright yellow liquid; that from the center, especially from the lower part of the trunk, was a solid. The study of the OLDVIRGIN-GROWTH SLASHPINE-(I) extractive in old virgin-growth slash pine revealed that sthe sapwood extractive differs not only in amount but also possesses marked differences in chemical and physical properties from that of the heartwood extractive. Sapwood extractive contains a high percentage of esters. Heartwood extractive contains a high percentage of free acids. Extractive from old sapwood may contain as high a percentage of unsaponifiable matter as is contained in heartwood extractive. Of the two extracts, the properties of the heartwood extractive approach those of gum oleoresin the more closely, Literature Cited
g3
h d
m lo
n rg
(1) Assocn. Official Agr. Chem., Methods of Analysis, 2nd ed., p. 295, 1925. (2) Barnes, Chem. M e t . E n q . , 28, 503-6 (1923). (3) Dupont and Barrand, Bull. I n s f . P i n . , 60, 155-161 (1929). (4) Dupont and Michaud, Chimie el Indusfrie, Special Number, M a y , 1924, p. 528. (5) Filipovich and Vuisotzkii, J. Chem. I n d . (Moscow),4, 953-60 (1927) (6) Gomberg. U. S. Dept. h g r . . Div. Forestry, Bull. 8, p. 34 (1893). (7) Griffin, "Technical Methods of Analysis." 1st ed., p. 328, McGraw-Hill, 1921. (8) Hawley, U.S. Dept. Agr., Forest Service, Bull. 106 (1913). (9) Schorger, IND. EKG CHEM, 6 , 723 (1914). I b i d . , 9, 560 (1917). (10) Schorger, A. W.. (11) Schwalbe a n d Ekenstom, CeZlulosechemie, 10, 11-18 (1929). (12) Sieber. R., "Uher das Harz der Nadelholzer und die Enthareung YOU Zellstoffen," 2nd ed., p. 26, Hofmann, Berlin, 1925. (13) Soum, Bull. Insl. Pin.,64, 253-64 (1929); 65, 277-91 (1929). (14) Soum, Ibid., 66, 279 (1929). (15) Wilson a n d Young, IND. END.CHBM.,9, 959-61 (1917).
