[8] This paper appears during the printing of the author's original MS.
[9] This paper appears during the printing of the author's original MS.
SECTION VI. THE LIGNOCELLULOSES
(p. 131) Lignocellulose Esters.—By a fuller study of the ester reactions of the normal celluloses we have been able to throw some light on the constitutional problems involved; and we have extended the investigations to the jute fibre as a type of the lignocelluloses, from the results of which we get a clearer idea of the relationships of the constituent groups.
Taking the empirical expression for the complex, i.e. the entire lignocellulose, the formula C12H18O9, we shall be able to compare the ester derivatives with those of the celluloses, which we have also referred to a C12 unit. But we shall require also to deal with the constituent groups of the complex, which for the purposes of this discussion may be regarded as (a) a cellulose of normal characteristics—cellulose α; (b) a cellulose yielding furfural on boiling with condensing acids—cellulose β; and (c) a much condensed, and in part benzenoid, group which we may continue to term the lignone group.
The latter has been specially examined with regard to its proportion of OH groups, as a necessary preliminary to the investigation of esters, in producing which the entire complex is employed. It will be shown that the ester groups can be actually localised in various ways, as in the main entering the cellulose residues α and β. But that the lignone group takes little part in the reactions may be generally concluded on the evidence of its non-reactivity as an isolated derivative, (1) By chlorination, &c. it is isolated in the form of an amorphous body, but of constant composition, represented by the formula C19H18Cl4O9. This compound, soluble in acetic anhydride, was boiled with it for six hours after adding fused sodium acetate, and the product separated by pouring into water. The dilute acid filtered from the product contained no hydrochloric acid nor by-products of action. The product showed an increase of weight of 7.5 p.ct. For one acetyl per 1 mol. C19H18Cl4O the calculated increase is 8.0 p.ct. It is evident from the nature of the derivative that this result cannot be further verified by the usual analytical methods. (2) The chlorinated derivative is entirely soluble in sodium sulphite solution. This solution, shaken with benzoyl chloride, with addition of sodium hydrate in successive portions, shows only a small formation of insoluble benzoate, which separates as a tarry precipitate. (3) The empirical formula of the lignone complex in its isolated forms indicates that very little hydrolysis occurs in the processes of isolation. Thus the chlorinated product we may assume to be derived from the complex C19H22O9. In the soluble by-products from the bisulphite processes of pulping wood the lignone exists as a sulphonated derivative, C24H23(OCH3)2.(SO3H).O7. The original lignone may be regarded as passing into solution as a still condensed complex derived from C24H26O12 (Tollens). There is evidently little attendant hydroxylation, and another essential feature is the small molecular proportion of groups showing the typical sulphonation.
It appears that in the lignone the elements are approximately in the relation C6: H6: O3, and it may assist this discussion to formulate the main constitutional types consistent with this ratio, viz.:
(1) The trihydroxybenzenes C6H3(OH)3.
(2) Methylhydroxyfurfural C5H2O.(OH)(CH3).
(3) Methylhydroxypyrone
