Method of preparing propylene epoxide

Abstract

The invention discloses a method of preparing propylene epoxide. The method comprises the following steps: adding raw materials propylene, hydrogen peroxide, a solvent methanol and a titanium silicalite molecular sieve catalyst into a reaction kettle in proportion, regulating the temperature and the pressure in the reaction kettle, and establishing a cycle; continuously adding the reaction raw materials and the solvent into a pipeline reactor to react from the outside of the reaction kettle, mixing the reaction raw materials and the solvent in a static mixer and then feeding the mixed materials and the solvent into a reaction kettle to react sufficiently to obtain the propylene epoxide. On the lower part of the reaction kettle, the reaction product propylene epoxide and the catalyst are separated under a certain pressure, so that the separated propylene epoxide enters a follow-up process, and the catalyst is fed into the equipment such as the pipeline reactor by virtue of a circulating pump outside the reaction kettle to return to the reaction kettle to continuously react. In the reaction kettle, backwashing is performed once every 10-300s to guarantee the continuity of the separation of the reaction. According to the method disclosed by the invention, the raw materials sufficiently contact with the catalyst, so that the conversion ratio of the hydrogen peroxide is not lower than 96%, and the selectivity of the propylene epoxide is not lower than 95%. The reaction separating device is reasonable in structural arrangement and stable in reaction.

Description

technical field [0001] The invention relates to a method for preparing organic matter, in particular to a method for preparing propylene oxide. Background technique [0002] Propylene oxide (PO) is the third largest propylene derivative besides polypropylene and acrylonitrile, and is an important basic organic chemical raw material, mainly used in the production of polyether, propylene glycol, etc. It is also the main raw material of the fourth-generation detergent non-ionic surfactant, oil field demulsifier, pesticide emulsifier, etc. PO derivatives are widely used in industries such as automobiles, construction, food, tobacco, medicine and cosmetics. In the prior art, methods for preparing PO mainly include chlorohydrin method, co-oxidation method and hydrogen peroxide method. The chlorohydrin method consumes a large amount of chlorine gas, causing serious equipment corrosion and environmental pollution. The co-oxidation method uses the alkyl hydroperoxide generated by ...

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Problems solved by technology

[0003] Above-mentioned two kinds of methods all adopt fixed bed technology, adopt fixed bed reactor, the effective contact area of ​​reaction raw material and catalyst is small, raw material conversion rate is low; The degree of danger of the reaction is high. In order to increase the conversion rate of raw materials and reduce the risk factor of the reaction, it is necessary to improve the process of preparing propylene oxide by the epoxidation of propylene

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