Calc. for Monobenzoate (a) C_{6}H_{10}O_{5} : 2.0-2.5 NaOH : C_{6}H_{5}.COCl-- 150.8} }164.0 (b) C_{6}H_{10}O_{5} : 2.0-2.5 NaOH : 1.5 mol. C_{6}H_{5}COCl 159.0} An examination of (a) showed that some dibenzoate (about 7 p.ct.) had been formed. The product () was exhaustively treated with cuprammonium solution, to which it yielded about 20 p.ct. of its weight, which was therefore unattacked cellulose. Under conditions as above, but with 2.5 mol. C_{6}H_{5}COCl, a careful comparison was made of the behaviour of the three varieties of cotton, which were taken in the unspun condition and previously fully bleached and purified. ___________________________________________________________________ | | | | | | | Sea Island | Egyptian | American | |________________________________|____________|__________|__________| | | | | | | Aggregate yield of benzoate | 153 | 148 | 152 | | Moisture in air dry state | 5.28 | 5.35 | 5.15 | | Proportion of dibenzoate p.ct. | 8.30 | 13.70 | 9.4 | | Yield of cellulose by | 58.0 | 54.0 | 58.3 | | saponification | | | | |________________________________|____________|__________|__________| It appears from these results that the benzoate reaction may proceed to a higher limit (dibenzoate) in the case of Egyptian cotton. This would necessarily imply a higher limit of 'mercerisation,' under equal conditions of treatment with the alkaline hydrate. It must be noted that in the conversion of the fibrous cellulose into these (still) fibrous monobenzoates, there are certain mechanical conditions imported by the structural features of the ultimate fibres. For the elimination of the influence of this factor a large number of quantitative comparisons will be necessary. The above results are therefore only cited as typical of a method of comparative investigation, more especially of the still open questions of the cause of the superior effects in mercerisation of certain cottons (see p. 23). It is quite probable that chemical as well as structural factors co-operate in further differentiating the cottons. Further investigation of the influence upon the benzoate reaction, of increase of concentration of the soda lye, used in the preliminary alkali cellulose reaction, from 20 to 33 p.ct. NaOH, established (1) that there is no corresponding increase in the benzoylation, and (2) that this ester reaction and the sulphocarbonate reaction are closely parallel, in that the degree and limit of reaction are predetermined by the conditions of formation of the alkali cellulose.