Sugar Alcohols. IX. A Physicochemical Study of the Erythritan–Boric Acid Complex

Abstract

In previous communications the authors (5,4) studied the influence of certain of the sugar alcohols and their anhydrides upon the dissociation constant of boric acid. In one study (4) it was demonstrated that erythritan, 1,4-anhydroerythritoI, was unique among the compounds investigated, inasmuch as its downward displacement of the titration curve of boric acid was greater than that of any other compound. This interesting property of erythritan prompted the present physicochemical investigation of the erythritan-boric acid complex. MATERIALS AND METHODThe boric acid was of buffer quality. The erythritan was prepared from erythritol by dehydration with sulfuric acid (3,1). The calculated values for its composition are as follows: carbon, 46.15 per cent; hydrogen, 7.69 per cent. Analysis gave the following composition: carbon, 46.02 per cent; hydrogen, 7.58 per cent. The levulose employed was Merck's crystals.The pH was determined electrometrically at 24°C.±1°, using the Wilson-type (7) hydrogen electrode. EFFECT OF ERYTHRITAN-BORIC ACID RATIO ON pHIn former studies the pH of a 4 per cent erythritan solution in onetenth molar boric acid was found to be 2.6. The following studies were instituted to determine the influence of varying concentrations of erythritan upon the pH of a solution of boric acid of fixed concentration. The results are set forth in figure 1, curve A.

SUGAR ALCOHOLS. X: The Effect of Certain Sugar Alcohols and Their Anhydrides on the Dissociation of Boric Acid

“…In previous communications the authors (7,8) have studied the influence of various sugar alcohols and their anhydrides on the dissociation of boric acid. Later the physicochemical properties of the erythritan-boric acid complex were studied (9). For the metabolism work carried out in this laboratory several more sugar alcohols, anhydrides, and other related compounds have been prepared for study.…”