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302 PALNER REFRACTIVE INDICES NOTE ON THE REFRACTIVE INDICES OF MIXTURES OF ISOPROPYL ALCOHOL AND ACETONE. BY DOROTHY MURIEL PALMER, DURING an investigation of the reduction of acetone to isopropyl alcohol it was found that none of the standard chemical methods was of use for the quantitative estimation of small quantities of alcohol in the presence of excesg of acetone. An examination of the refractive indices of mixtures of the two substances showed, however, that the relationship between the percentage compositions and refractive indices of the mixtures could be represented by a very flat aurve, and it was thought that this might serve 8s a rapid method for determining the composition. The chief practical difficulty was due to the extreme volatiIity of acetone. Little adjustment of the refractometer could be made after placing the liquid in the observation cell, and the time allowed for its temperature to become constant had necessarily to be short. The acetone was dried over calcium chloride, fractionated, purified by means of its compound with sodium iodide, according to the method of E. A. Werner and Shipsey (J. Clzem. Soc., 1913, 103, 1255), and then refractionated under a , Young dephlegmator stillhead. The final fraction boiled at 56G0 to 56.55" C. (barometer =76*63 cm.). The koprogyl alcohol was prepared from this acetone by reduction with hydrogen in the presence of heated nickel, according to the method of Sabatier. It was then dried over fused sodium sulphate and fractionated three times with an eighf-pear column. The final fraction boiled at 80" to 81" C. (barometer, 76.02 em.). The readings were taken with a Pulfrich refractometer at a constant temperature of 22' C., values being observed for the hydrogen C and F lines. Composition. Per Cent. Alcohol. 0.0 1.38 1-95 2.41 3.5 5.07 8.24 9.71 1349 15-1 16.2 29.3 53.8 67 -3 67.3 73.3 89 *9 100.0 Refractive Indices. Hydrogen C. Hydrogen F. 1.35633 1*36296 1.35655 1.36324 1.35651 1-36316 1035660 1 -36324 1 e35701 I -36358 1 -35 7 1 4 1.36378 1.35754 1,36425 1 *35772 1.36436 1.35834 1.36492 1-35862 1.36586 1.35871 1436534 1,36097 1.36768 1.3663'7 - 1.36179 1.37443 1;36763 1,37416 1.36940 1.37592 1 a37225 1*37861 1.37470 1.38121 THE UNIVERSITY CHEMICAL LABORATORY, CAMBRIDGE. Published on 01 January 1920. Downloaded by University of North Carolina at Chapel Hill on 31/10/2014 11:55:00. View Article Online / Journal Homepage / Table of Contents for this issue

Note on the refractive indices of mixtures of isopropyl alcohol and acetone

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302 PALNER REFRACTIVE INDICES

NOTE ON THE REFRACTIVE INDICES OF MIXTURES OF ISOPROPYL ALCOHOL AND ACETONE.

BY DOROTHY MURIEL PALMER,

DURING an investigation of the reduction of acetone to isopropyl alcohol it was found that none of the standard chemical methods was of use for the quantitative estimation of small quantities of alcohol in the presence of excesg of acetone. An examination of the refractive indices of mixtures of the two substances showed, however, that the relationship between the percentage compositions and refractive indices of the mixtures could be represented by a very flat aurve, and it was thought that this might serve 8s a rapid method for determining the composition.

The chief practical difficulty was due to the extreme volatiIity of acetone. Little adjustment of the refractometer could be made after placing the liquid in the observation cell, and the time allowed for its temperature to become constant had necessarily to be short.

The acetone was dried over calcium chloride, fractionated, purified by means of its compound with sodium iodide, according to the method of E. A. Werner and Shipsey (J. Clzem. Soc., 1913, 103, 1255), and then refractionated under a, Young dephlegmator stillhead. The final fraction boiled at 5 6 G 0 to 56.55" C. (barometer =76*63 cm.).

The koprogyl alcohol was prepared from this acetone by reduction with hydrogen in the presence of heated nickel, according to the method of Sabatier. I t was then dried over fused sodium sulphate and fractionated three times with an eighf-pear column. The final fraction boiled at 80" to 81" C. (barometer, 76.02 em.).

The readings were taken with a Pulfrich refractometer at a constant temperature of 22' C., values being observed for the hydrogen C and F lines.

Composition. Per Cent. Alcohol.

0.0 1.38 1-95 2.41 3.5 5.07 8.24 9.71

1349 15-1 16.2 29.3 53.8 67 -3 67.3 73.3 89 *9

100.0

Refractive Indices. Hydrogen C. Hydrogen F.

1.35633 1*36296 1.35655 1.36324 1.35651 1-36316 1035660 1 -36324 1 e35701 I -36358 1 -35 7 1 4 1.36378 1.35754 1,36425 1 *35772 1.36436 1.35834 1.36492 1-35862 1.36586 1.35871 1436534 1,36097 1.36768 1.3663'7 - 1.36179 1.37443 1;36763 1,37416 1.36940 1.37592 1 a37225 1*37861 1.37470 1.38121

THE UNIVERSITY CHEMICAL LABORATORY, CAMBRIDGE.

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