Studies on the influence of mannitol and dulcitol and certain of their anhydrides on the dissociation of boric acid were reported in a previous communication (7). In general, the increased dissociation of boric acid produced by sugar alcohols was exhibited to a lesser degree or not at all by their anhydrides. Another series of these substances has been made available for study, and further investigations as to the effect of these compounds on the dissociation of boric acid have been instituted. MATERIALSThe-inositol, erythritol, pentaerythritol, and adonitol employed were Pfanstiehl's c.p. products and met the specifications of their catalogue.Ethylene glycol, ethylene oxide, propylene glycol, propylene oxide, and trimethylene glycol were supplied by the Eastman Kodak Co. The dihydroxyacetone employed was Oxantin, prepared formerly by Merck and Co. The epihydrin alcohol was prepared from epibromhydrin (1). The Z-epihydrin alcohol, distilling at 70°C. at 10 mm. pressure, was employed. The polygalitol was extracted from poly gala amara (9). The compound melted at 138°C. (uncorrected). The erythritan was prepared from erythritol by dehydration with sulfuric acid (2,6). Analysis gave the

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Das kathodische Verhalten von 85‐100%iger Schwefelsäure in Abhängigkeit von Kathodenmaterial, von der Temperatur und von der Wasserkonzentration wird untersucht.

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.

The relationship between chemical constitution and sweet taste has not been elucidated satis-

In a former communication the authors (1935) presented studies on acid and gas formation by members of the colonaerogenes-intermediate groups in the presence of sugar alcohols and their anhydrides. In general it was observed that mannitol and dulcitol are fermented by many organisms of this group, but that their anhydrides are not utilized as determined by ordinary fermentation tests. So striking was the resistance to utilization of the anhydrides in contrast to the ease of metabolism of the sugar alcohols themselves that the study was extended in order further to elucidate the relationship between chemical constitution and fate in the bacterial economy. CHEMICAL CONSTIT ONThe following formulas show the structural relationships of the substances employed. H

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In einer speziell entwickelten Vibratorzelle ist es möglich, trotz starker Gasentwicklung während der Reaktion mit einem geringen Elektrodenabstand und somit niedriger Zellspannung zu arbeiten.