Studies of the processes operative in solutions. XXVIII.-The influence of acids on the rotatory power of cane sugar, of glucose and of fructose

It is shown in Part XXII of this series of studies that when cane sugar is hydrolysed in the presence of solutions of sulphuric acid of different concentrations, the ratio of the final value of the rotation of the invert sugar to the initial value due to the cane sugar becomes very considerably greater as the concentration of the acid is increased. The effect was attributed to an increase in the optical rotatory power of the sugars caused by the acid; from the fact that the ratio of acid to sugar was the same in most of the experiments, it was argued that the determining factor was the ratio of acid to water, the alteration in the rotatory power being due mainly to changes in the water. Judging from the results of preliminary experiments and the work of previous investigators, it was probable that the fructose was the sugar chiefly affected but that observed change in the above ratio could not be attributed to this cause alone. In the course of experiments recently carried out to determine the hydrolytic activity of benzenesulphonic acid at different degrees of dilution, data have been accumulated which confirm the results arrived at when sulphuric acid was used as the hydrolyst. Experiments have also been carried out to determine the effect of the acid on the rotatory power of cane sugar, glucose and fructose.