SU1242753A1 - Method of determining hydroperoxide of isopropyl benzene - Google Patents

Abstract

The invention relates to analytical chemistry, in particular to a method for the quantitative determination of isoprophenbenzene hydroperoxide. In order to simplify the method and increase its sensitivity and accuracy, the determination of isopropylbenzene hydroperoxide is carried out by dissolving the analyzed sample in cumene, treating the resulting solution with oxygen at 80-120 ° C, followed by analysis of the oxygen absorption rate. Sensitivity. Determination is not lower than 5 10 M isopropyl benzene hydroperoxide in cumene. With a gasometric sensitivity of 0.5 mm / min, the lower limit of detectable concentrations. With a determination accuracy of no less than 1%, it is 0.001 M.

Description

Igitbreteiii belongs to the analytical chemical, in particular to methods for the quantitative determination of isopropyl benzene hydroperoxide.

The aim of the invention is to simplify the method and increase the sensitivity and accuracy of the determination.

Example 1. For analysis, a solution is prepared of isopropylbenzene hydroperoxide in cumene at a concentration of 10 by concentration of isopropyl hydroperoxide.

0.050 M. A solution in an amount of 10 ml is placed in a round-bottom flask with a volume of 11-15 ml, flushed with oxygen and connected to a gasometric apparatus filled with oxygen. Then the flask with the analyzed solution is placed in a thermostat with a temperature and after 2 minutes, necessary for heating the reaction mixture, while shaking 5–7 times per second, the oxygen absorption rate is determined. It is equal to (125 + 1) mm / mich. Then, the concentration of isopropylbenzene hydroperoxide is determined according to the calibration graph. It is equal to (0.050 + 0.0005) M. The relative error is 1%. Analysis time 5-10 min.

Example 2. Analysis of a solution of isopropyl benzene hydroperoxide at a concentration of 0.050 M is carried out as in Example 1 at a temperature of 80 ° C. The oxygen uptake rate is (28 + 0.5) mm / min. The concentration of hydroperoxide is (0,, 004) M; relative error 2%. Analysis time 5-10 min.

Example 3. Analogously to Examples 1 and 2, the concentration of isopropylbenzene hydroperoxide O., 050 M; temperature is 1–20 ° C. The speed is oblique (490 + 2) mm / min, the concentration of hydroperoxide is (0.050 + 0.0004) M. The relative error is 0.8%. Analysis time 5-10 min.

Example 4. For analysis, a solution of isopropyl benzene hydroperoxide in cumene with a concentration of 0.200 M is prepared. 1 ml of the solution to be analyzed and 9 ml of cumene purified from hydroperoxide are passed through an alumina column through a flask. 100 C.

Oxygen absorption rate (78 + 1) mm / min. The concentration of hydroperoxide is (0.200 + 0.004) M. The relative error is 2%. Analysis time 5-10 min.

The selected temperature range is explained by the fact that below, 80 ° C, the decomposition rate of isopropylbenzene hydroperoxide is small, and above 120 ° C, a spontaneous thermal initiation is added to the initiation rate due to decomposition of hydroperoxide.

Calibration graph is constructed by analyzing solutions with a known con20.

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benzene at coordinates: concentration. isopropylbenzene hydroperoxide in m / l — the rate of oxygen absorption in mm / min is determined for the first temperature.

An aliquot of the analyzed solution is selected so that when the cumene is brought to 10 ml, the concentration of hydroperoxide is no higher than 0.2 M at 80 ° C, o, M at 100 ° C and 0.05 M at 120.0.

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Otherwise, shaking the reaction flask does not ensure that the solution is saturated with oxygen.

The sensitivity of the method is determined by the accuracy of the velocity measurement.

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absorption of oxygen and not less than 5 10 M hydroperoxide isopropyl benzol in cumene.

 The accuracy of the method depends on the size of the aliquot of the analyzed solution and the sensitivity of the gas-metric. This installation, so that with a gasometric installation sensitivity of 0.5 mm / min, the lower limit of detectable concentrations, determined by its accuracy not lower than 1%, is 0.001 M-.

Compared to the known method, the sensitivity is higher than 4 times, the accuracy of determination is 2 times. The proposed method is simpler, since it is necessary to carry out fewer operations than it is known

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Claims (1)

Claims. : The method of determining isopropylbenzene hydroperoxide by dissolving the sample being analyzed, treating the resulting solution with a chemical reagent, followed by analysis, in order to simplify the method and increase the sensitivity and accuracy of the determination, dissolving is carried out in cumene; oxygen is used as chemical agent and at 80-120 ° C and the analysis is carried out on the rate of absorption of oxygen.