Preparation method of epoxy chloropropane

Abstract

The invention provides a preparation method of epoxy chloropropane. The preparation method comprises the following steps: performing reverse feeding on chloropropene and hydrogen peroxide by adoptinga fixed bed catalytic reactor, maintaining a solvent in a reaction bed layer containing a catalyst by utilizing the balance of solvent gasification and condensation, and reacting chloropropene and hydrogen peroxide in the reaction bed layer to generate epoxy chloropropane. The preparation method provided by the invention is beneficial to promoting sufficient reaction of chloropropene and hydrogenperoxide in the reaction bed layer, so epoxy chloropropane with relatively high purity is generated, meanwhile, potential safety hazards are reduced, the problem that a catalyst is difficult to separate in the slurry bed reaction process is solved, and the temperature control problem in traditional fixed bed reaction is solved; and reaction and separation are combined in one fixed bed reactor, soepoxy chloropropane is prepared with simple process, low energy consumption and high efficiency.

Description

technical field [0001] The invention relates to the field of preparation of organic chemical intermediates, in particular to a method for preparing epichlorohydrin. Background technique [0002] Epichlorohydrin is an important organic chemical intermediate, mainly used in the production of epoxy resin. In the existing industrial chlorohydrin method, dichloropropanol is prepared through chlorohydrinization reaction of chloropropene, chlorine gas and water, and then further saponified to obtain epichlorohydrin. In the chloroalcoholation reaction, chlorine gas is used as the oxidant and chlorine source, and water provides hydroxyl groups. The reaction mechanism is that the hypochlorous acid oxidized the double bond of chloropropene generated by the reaction of chlorine gas and water, and the electrons on the double bond are transferred to the chlorine atom. At the same time, the chlorine atom Addition to the double bond, followed by nucleophilic attack of the hydroxyl group on...

AI Technical Summary

Problems solved by technology

The chlorohydrin method has the following disadvantages: using highly toxic chlorine as a raw material, it significantly reduces safety; the chemical properties of chlorine are active, and side reactions are prone to occur, such as direct addition reactions with chloropropene to generate low-value trichloropropane. It is necessary to add a large amount of water to dilute the chlorine concentration in the reaction system, and control the concentration of the target product dichloropropanol to be lower than 4%, which not only makes the energy consumption of the saponification separation process high, but also produces more than 40 tons of chlorine-containing wastewater per ton of epichlorohydrin. There are also about 2 tons of waste residue, and the by-product trichloropropane is as high as 7%, which is difficult to handle

However, since the epoxidation process of allyl chloride is a strong exothermic reaction, it is difficult to control the reaction temperature when a fixed bed is used, resulting in more by-products and potential safety hazards.

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