RU2378253C1 - Method of preparing ethylbenzene hydroperoxide - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to petrochemical industry and can be used in combined production of styrene and propylene oxide. Ethylbenzene hydroperoxide is obtained in accordance with the invention by oxidising ethylbenzene with atmospheric oxygen in a continuous reactor at atmospheric pressure in the presence of N-hydroxyphthalimide as a catalyst in amount of 0.5-3 wt % and temperature of the process of 125-130°C until achieving content of ethylbenzene hydroperoxide of 19.2%.

EFFECT: increased conversion of ethylbenzene and selectivity of the process.

1 cl, 1 ex

Description

The invention relates to the petrochemical industry and can be used in the process of joint production of propylene oxide and styrene.

It is known that hydroperoxides of alkyl aromatic hydrocarbons are obtained by oxidation of the corresponding hydrocarbon at elevated temperatures in the presence of alkaline additives and an oxidation initiator, followed by isolation of the target product by known methods (ed. St. USSR No. 259884, class C07C 179/035 A, publ. 22.12.69 and Bull. No. 3, 1979).

To increase the selectivity of the process, oxidation is carried out in the presence of a catalyst — chromium-nickel steel containing chromium, nickel, titanium, manganese, etc. In this case, the reactor or nozzle in the form of rings or shavings from the specified steel can serve as a catalyst. The disadvantages of this method are the low rate of accumulation of oxidation products and a significant content of carboxylic acids in the oxidate and, as a result, a significant loss of propylene oxide at the stage of propylene epoxidation with ethylbenzene hydroperoxide.

A known method of producing ethylbenzene hydroperoxide by liquid-phase catalytic oxidation of ethylbenzene at an elevated temperature with an oxygen-containing gas in the presence as a catalyst of a mixture of metal compounds of constant valency 1a and / or 2a of groups of the 3rd and / or 4th periods and variable valencies of 7b and / or 8b groups Of the 4th period of the Mendeleev system, taken in the total amount per metal 0.0001-0.0031 wt.% With a total weight ratio of metals of constant valency to metals of variable valency equal to 30 0-1: 1-100 [patent RU No. 2128647 C1, publ. 1998.03.10].

However, the method requires high energy costs, has a low conversion of ethylbenzene of not more than 8.1%, requires the use of catalysts consisting of a mixture of a large number of organic and inorganic components.

Closest to the proposed is a method of producing ethylbenzene hydroperoxide by liquid-phase oxidation of ethylbenzene with atmospheric oxygen in the presence of 0.00001-5.0 wt.% N-hydroxyphthalimide catalyst under a pressure of 6 K (kg / m) at a temperature of 40-120 ° C with preliminary dissolution of N -hydroxyphthalimide in ethylbenzene and the further introduction of sodium carbonate [patent RU No. 2186767 C2, publ. 2002.08.10].

However, the method has insufficient conversion (~ 17%) and selectivity for the formation of ethylbenzene hydroperoxide (~ 87%). The technical task of this invention is to increase the conversion of ethylbenzene and the selectivity of the formation of hydroperoxide.

This technical problem is solved using the method of producing ethylbenzene hydroperoxide by liquid-phase oxidation of ethylbenzene with atmospheric pressure and a temperature of 125-130 ° C in the presence of 0.5-3 wt.% N-hydroxyphthalimide as a catalyst. Under these conditions, it is possible to achieve a conversion of ethylbenzene of ~ 19.2% with a selectivity of formation of ethylbenzene hydroperoxide of 90-94%.

The present invention is illustrated by the following example.

Example

The oxidation of ethylbenzene with oxygen by the air is carried out on a laboratory bench made of metal, equipped with water and carbon dioxide refrigerators, dosing and temperature control systems, at a temperature of 130 ° C and a volumetric air flow rate of 250 h ^-1 . Ethylbenzene fed to the oxidation contains N-hydroxyphthalimide catalyst in an amount of 3 wt.% The reaction is carried out for 3 hours. The obtained ethylbenzene hydroperoxide is determined by iodometric titration, the composition of the organic part of the oxidate is determined by gas-liquid chromatography, and the acid is determined by titration with an alcohol solution of alkali with methyl orange in acetone.

Ethylbenzene conversion was 22.4% with an ethylbenzene hydroperoxide selectivity of 94.2%.

Thus, in comparison with the prototype, the conversion of ethylbenzene is higher by 29%, the selectivity of the formation of ethylbenzene hydroperoxide is higher by 8%.

Claims (1)

The method of producing ethylbenzene hydroperoxide by liquid-phase oxidation of ethylbenzene with atmospheric oxygen in the presence of 0.5-3.0 wt.% N-hydroxyphthalimide as a catalyst in relation to ethylbenzene in a continuous reactor, characterized in that the oxidation is carried out at a temperature of 125 -130 ° C.