I n t he prese nt investigation, the cha nges in the equilibrium specifi c r otation ca used by t he addi tion of either sodium or potassiu m tetr aborate to solu t ions of D-glucose, D-fru ctose, L-sorbosc, s ucrose, mannitol, a nd sorbi tol have bee n obser ved a nd t he results in tc rpret ed . Measure ments h ave been m ade fo r various conce ntra tions of carbohydrat es with fi xed co nce nt rations of borat c, and for vari ous conce ntr ations of borate wit h fi xcd co nce ntr atio ns of carboh ydratc. It was t hus possible to obser ve independently t he effcct of variatio n in t he co ncentration of eit her carboh ydrate or bor ate. The resul ts indi cate t h at glucose, fru ctose, sor bose, a nd sorbitol for m t hree b orate co mpounds, t hat m a nnitol forms two, a nd s ucr ose one. T he optical rotations of the compo unds ha ve bee n estimaLed, a nd t he co mposition of t hc solutions disc ussed . Exte nsive ta bles have been i nclud ed, givin g t he op tical r otations of t he above-me ntio ned carbohydrates i n the pr esence of sodium a nd potassiu m tet raborat e.

In the present investigation determinations were made of the quantities of oxalate, tartrate, and trihydroxyglutarate fo rmed by the oxidation of galaeturonic acid and of 5-keto-gluconic acid in the presence of various bases and various concen trations of the base. Although preliminary measu rements indicate that the proportions of the products can be altered by use of catalysts, this report is restricted to the results obtained without the addition of catalytic substancC's.

A simple procedure is reported for the preparation of crystalline mannuronic lactone from algin. The algin is converted to alginic acid, which is hydrolyzed by the action of concentrated sulfuric acid followed by dilute acid. In contrast to prior methods, the lactone is crystallized directly from the hydrolyzate of alginic acid without the intermediate separation of the amorphous barium salt or the cinchonine salt. The yield is from 25 to 30 percent of the alginic acid used. The preparation and properties of crystalline sodium mannuronate and potassium mannuronate monohydrate are also described.

No abstract