The control of fractional distillation by means of refractive index measurements

Abstract

MnO, produced Erom the MnSO, proved e f f d v e in alkaline solution. MnSO, was ineffective in acid solution. None of the other substances gave any evidence of assisting oxidation either in acid or alkaline solution. Series 111. Amorint of uatalyst.-Various amounts ofMnS0, were used and the times for reaching equilibrium compared. T o '50 ml. hl/Io Cr,(S04), were added 30 ml. 5~-sodium hydroxide and 20 ml. distilled water and the following amounts of ioyo MnSO, solution: 2 ml., I ml.,o.ag ml., 0 . xoml. 0.05 ml.ando.01 ml. There waslittle differencein oxidationrate between I ml. and 2 ml. but with quantities ofcatalyst less than this amount the rate of oxidation decreased rapidly. Also the 2 ml. were added in lots o f f ml. at intervals of one half hour. Table I1 indicates that I ml. of catalyst was the optimum. Figures are the mean of several oxidations and showed much variation. TABLE I1 Amount of camalyst Time for equilibrium : & Oxidation to I . 2 ml. in 4 lots 0.5 ml. at b hour intervals . 3 hours 6 5 % 7 0 8 2. -2 ml. 3 hours 65 %-70 I o 3. I ml. 3 hours 65 O/b-70% 4. 0.25 ml. 5 hours 35 %-4OO/ O 6. 0.05 ml. Indefinite negligible 7. 0.01 ml.