Continuous production method of epoxy chloropropane by hydrogen peroxide process

Abstract

The invention provides a preparation method of chloroepoxy propane by chloropropene epoxidation. Chloropropene, a solvent and titanium silicalite molecular sieve catalyst fine particles are put in a reaction kettle for reaction at the temperature of 10-80 DEG C. The method is characterized in that the reaction kettle is a single kettle or multistage slurry bed reaction kettles with same or different volumes which are connected in series; the reaction solution needs not to be homogeneous phase, slurry particles of the chloropropene, the solvent and the titanium silicalite molecular sieve catalyst are added to a first stage reaction kettle by a metering pump, hydrogen peroxide is dropwise added to the first stage reaction kettle or each stage of the reaction kettles, the reaction occurs in a weakly acidic condition, materials are subject to oil-water delamination after the reaction to be divided into oil-phase slurry and water-phase slurry; the catalyst is suspended in the water phase, and the oil phase is sent to a rectification tower to separate the chloropropene, the epichlorohydrin and trace methanol; the water phase slurry is filtered, a catalyst filter cake or concentrated slurry is directly beaten by the solvent, and pumped to a first stage epoxidation reaction kettle, the water phase slurry contains the methanol, trace epichlorohydrin and the water which is generated by the reaction and the water which is taken by the hydrogen peroxide, the trace methanol and the epichlorohydrin are separated out by negative pressure rectification, and the recovered methanol is used for preparation of the catalyst slurry. The method has the advantages of simple process, little solvent consumption and high product separation yield, and is available for industrialized production.

Description

technical field [0001] The present invention relates to the production method of epichlorohydrin, specifically, relates to a kind of using titanium-silicon molecular sieve as catalyst, hydrogen peroxide as oxidant, carrying out slurry bed continuous reaction, catalyzing the direct epoxidation production of chloropropene The method for epichlorohydrin belongs to the technical field of organic chemical industry. Background technique [0002] Epichlorohydrin (ECH) is an important bulk organic chemical raw material and fine chemical product, and is the third largest epoxide in output after ethylene oxide and propylene oxide. Widely used in the synthesis of epoxy resin, glycerin, chlorohydrin rubber, etc. [0003] At present, epichlorohydrin is produced from propylene as a raw material, and the production method is mainly the chlorohydrin method, which is an indirect method for synthesizing epichlorohydrin from allyl chloride (AC), and the synthetic route is relatively long. Th...

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Problems solved by technology

Due to the absence of solvent, the activity of the catalyst decreases rapidly and the life is short, which is not conducive to the recycling of the catalyst, and also increases the frequency and cost of catalyst regeneration

[0008] To sum up, there are existing methods for continuous preparation of epichlorohydrin. ①A fixed-bed or trickle-bed reactor is used to realize continuous material, and the reaction liquid phase material must be homogeneous, so the amount of solvent used is large and the separation capacity is high. The consumption is high, allyl chloride and epichlorohydrin are directly separated from a large amount of methanol and water by atmospheric distillation, and the by-products will increase if the temperature is above 50 °C, and the separation yield of epichlorohydrin is low; if negative pressure distillation is used for separation, The loss of allyl chloride is large, the recovery rate is low, and the cost increases; if an extractant is used, new components will be introduced and the complexity of the process will be increased

2. Kettle type or supergravity continuous reaction does not use new solvents, directly using chloropropene not only as the reaction raw material, but also as the reaction solvent will cause: on the one hand, alcohol, ketone, etc. are not used as solvents, and the catalyst is in the liquid phase (chloropropene and hydrogen peroxide) ) has high surface tension and poor dispersion performance. On the other hand, it is not conducive to the diffusion of reaction products in the catalyst pores, the catalyst activity decreases rapidly, the service life is short, and the catalyst regeneration frequency and use cost increase.

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