June, 1943
THECOURSEOF FORMATION OF NATIVELIGNININ SPRUCE BUDS
1195
(11, Table 11) and lower (I, Table 11) "flats" of the fractionation curves as given in Fig. 1, Cooke, McCarthy and Hibbert" in the range W * ~ D1.4600-1.4700. The melting points of the urethans are given in Table 1 1 .
Company and the Canadian Pulp and Paper Association. Summary 1. Use of a much more efficient fractionation 'I'ARLR I1 technique has resulted in the isolation of a new PIIENYLURETHANS OF HYDROGENATED LIGXINFRACTIONS' product, 3-cyclohexyl-1-propanol,from the hyMaterial M. p. of drogenation products of maple wood and maple urethan, tested, ):?iD Lignin type QC. ethanol lignin fractions. Its synthesis was carEthanol lignin I 1.4635 129-130 ried out by hydrogenation of cinnamyl alcohol I1 1.4678 87-88 over copper chromite in dioxane solution. I 1.4618 129-130 Benzene-soluble 2 . The hydrogenation of 3-hydroxy-l-(4hyethanol lignin I1 1.4660 87-88 droxy-3-methoxypheny1)1-propanone over copI 1.4615 129-130 Ethanol lignin tars per chromite in dioxane solution gives a mixture I1 1.4675 87-88 of 4-n-propylcyclohexanol and 3-cyclohexyl-lComparison of mixed melting points with the phenyl propanol in the ratio of 24 and 76%, respectively. urethans from the corresponding pure synthetic derivatives Total yield 81%. proved that each of the products melting at 87-88' (11) 3. The results obtained provide support for was the urethan of 3-cyclohexyl-1-propano1, while those melting a t 129-130' (I) were the urethans of 4-n-propyl- the view that the side chains attached to the cyclohexanol. aromatic nuclei in the structure of native lignin Acknowledgment.-The authors wish to ac- contain the terminal grouping -CHZOH or knowledge the kind financial assistance accorded -CH,-O-C--. one of them iJ. R. B.) by the Canada Paper MONTREAL, CANADA RECEIVED MARCH 11, 1918
[CONTRIBUTION FROM THE
DIVISIONO F
INDUSTRlAL AND CELLULOSE CHEMISTRY,
MCGILLUNIVERSITY]
Studies on Lignin and Related Compounds. LXXI. The Course of Formation of Native Lignin in Spruce Buds' BY JOHN R. BOWER,
JR.,
LLOYD M. COOKEAND HAROLD HIBBERT
In connection with the question of formation and mode of synthesis of lignin in the plant-the subject of several communications by Hibbertzit is of importance to know a t what stage of growth the initial appearance of lignin takes place. In the interesting and instructive experiments carried out by Phillips, et al.,3using oat shoots as their plant material, it was found that the percentage of lignin (determined by use of fuming hydrochloric acid) in the culms, sheaths, leaves and roots remained a t a nearly constant, low level (2-2.5% of the culms, sheaths and leaves; 5.6-6.2% of the roots) during the first six weeks of growth and then increased rather rapidly and uniformly until maturity was reached in fifteen ( 1 ) This paper represents part of a thesis submitted to the Faculty of Graduate Studies of McGill University by John R. Bower, Jr.. November, 1942, in partial fulfillment of the requirements for the degree of Doctor of Philosophy. (2) (a) Hibbert, Paper Trade J . , 118, No.4, 35 (1941); (b) Hibbert, Ann. Reu. B i o c h e m . / l l , 183 (1942). (3) Phillips, Goss, Davis and Stevens, J . A g r . Research. 69, No. 5, 319 (1939).
weeks (final lignin values: culms, sheaths and leaves, 11%; roots, 12.5%). It was desirable to ascertain whether a similar behavior is shown by growing spruce tips and since it has been found that the presence of propylphenol derivatives is definitely associated with the presence of lignin in plant materials,' it appeared possible that an analytical determination of such products, in the form of their hydrogenated propylcyclohexyl derivatives, might serve as a method for determining qualitatively, and possibly quantitatively, the amount of lignin present. In order to establish a reference basis, ethanolbenzene extracted mature spruce wood (3540 years old) was hydrogenated in dioxane solution over copper chromite catalyst under conditions (4) (a) Cooke, McCarthy and Hibbert, THISJOURNAL, 68, 3056 (1941); (b) Godard, McCarthy and Hibbert, ibid., 68, 3062 (1941)l (4 Bower, McCarthy and Hihhert, i b i d . , 68,3066 (1941); (d) Harris, D'Ianni and Adkins, ibid., 60, 1467 (1938): (e) Bower, Cooke and Hibbert, ibid., 66, 1192 (1943).
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JOHN
K . HOW‘RK,J K . , LLOYDM. COOKEAND H.\ROLD HIRREKT
Vol. 6.i
previously found suitable for the complete (as compared to 1 to 7,; for mature woods), the hvdrogenation and liquefaction of maple wo0d4b*4e ethanol extract was concentrated to dryness arid and the water-white liquid reaction products also hydrogenated. Thus the total hydroqetia separated into water-soluble and water-insoluble tion products of Stage 1 spruce tips were o1:tainecl portions according to the previously reported in two portions. Separation and fractionation of procedure.4e Fractional distillation of these two the hydrogenation products from both sources products through the newly-developed, highly (ethanol-soluble and ethanol-insoluble) shovr et1 efficient, spiral screen-packed laboratory column5 the complete absence CJI any of the three bnowii (28 theoretical plates) yielded the three propyl- propylcyclohexyl derivatives found in the hydro cyclohexyl derivatives (reported previously from geriation products of mature spruce wood (Figs maple : I-n-propylcyclohexanol ( 1 .O‘ 1 arid 2 ) . ’This was taken as a proof that lignin of wood weight), 3-cyclohexyl-1-propanol (1.4c/C), had not yet been formed, a t least in significant and 3-(4-hydroxycyclohexyl)-l-propanol(0.9(6’), amount, in three weeks old spruce tips (SfaxeI ) LI‘hen dried, unextracted, Stage 11 spruce tips the combined yield amounting to 4.2‘; of thc original dry wood weight (three and a half to four months old) were hydrogeiiated under the same conditions, and the lir,ow SHEP,T 1 products examined similarly, it was found I K 4C I I O \ h l LON IJKOCEDURb POR SPRUCI H Y U K O G b N . \ I IOY that one of the Iropylcyclohexyl derivatives, PRODUCTS (Expi 111) i-n-I’rupylcycIohexanol, previously isolated nzonnne .Solution of Spruce Hydroqenatton Product5 from mature spruce wood, was present to , Concentration through the extent of OS%;, of the weight of the Fenske columnbfollowed by original material (see Fig. 3, “flat” I). The vacuum concentration to 80 1 a t 20 mni pre5sure 111 Perry other two known propylcyclohexyl derivaWidmer- flash tives were absent. From these results it may bc concluded that toward the end of -- - - Water, hioxane one growing season the amount of lignin (products
