Titanium-silicon molecular sieve compound catalyst and preparation method thereof

Abstract

The invention discloses a titanium-silicon molecular sieve compound catalyst and a preparation method thereof. The method comprises the following steps of: fully mixing a titanium-silicon molecular sieve, an acid molecular sieve, a polymeric monomer polyene-based compound and a pore forming agent; undergoing a polymerization reaction in the presence of an initiator; smashing an obtained lump solid catalyst; adding into a halogenated hydrocarbon for swelling; and extracting and activating with a solvent to obtain a molded titanium-silicon molecular sieve compound catalyst. Due to the adoption of the catalyst obtained in the invention, a corresponding process for preparing a corresponding diol compound by performing alkene epoxidation and undergoing a one-step hydration reaction can be realized, the problem of difficulty in separating titanium-silicon catalyst powder from a reaction solution can be solved simultaneously, and the reaction efficiency is increased. The catalyst is particularly suitable for catalytic reaction processes for preparation of ethylene glycol from ethylene, preparation of 1,2-propylene glycol from ethylene, alkene epoxidation, preparation of alcohol ether by etherification, and the like with a fixed bed process.

Description

technical field [0001] The invention belongs to a molecular sieve catalyst and a preparation method thereof, and is particularly suitable for catalytic reaction processes such as olefin epoxidation and hydration to prepare ethylene glycol or propylene glycol, and olefin epoxidation and etherification to prepare alcohol ethers. Background technique [0002] In the process of olefin epoxidation and hydration to prepare diols, since the conversion from olefins to diols is a two-step continuous reaction, two catalytic reaction systems, selective oxidation and acid catalysis, are involved. In the traditional production process, the epoxidation of olefins to alkylene oxide and the subsequent hydration reaction of alkylene oxide are carried out separately, mainly because the reaction conditions of the two reactions are too different, and the water required for the hydrolysis of alkylene oxide was added in the second reaction step. [0003] Ethylene glycol is an important petrochem...

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Problems solved by technology

[0006] In the application of olefin epoxidation, titanium-silicon molecular sieve catalysts exhibit excellent shape-selective catalytic performance. Generally, the smaller the particle size, the higher the catalyst activity and the better the selectivity. In practical applications, the particle size of titanium-silicon molecular sieve catalysts is about 0.1-15.0μm, however, such a small particle size will bring great difficulties to the separation of the catalyst and the product, although various research results on filter materials have been applied in practice, but for the separation of titanium silicon molecular sieve catalysts and products Separation, the resistance generated during filtration does not lie in the size of the pores of the filter material, but comes from the extremely fine catalyst particles occupying and blocking the pores of the formed filter cake, especially the catalyst particles with a particle size of less than 2 μm are the most suitable for filtration. Unfavorable, this results in low production efficiency and also affects the process of industrial application of titanium silicon molecular sieves

The catalyst with small particle size will not only block the pores of the filter cake during filtration, but part of it will be lost from the pores of the filter medium. The general loss rate is about 5% to 8% of the input amount of the catalyst, which not only causes unnecessary consumption of the catalyst, but also enters the product. Further side reactions are caused in the material, leading to an increase in separation costs and affecting product quality

[0007] CN1256274A has proposed the technology that titanium-silicon molecular sieve catalyzes propylene, hydrogen peroxide epoxidation to continuously produce propylene oxide, in this process, catalyzer exists with slurry state, although obtained better raw material conversion rate and product yield, but because catalyzer It is in a slurry state and needs to be separated from the product after the reaction for reuse

This leads to a cumbersome process flow, which is not conducive to large-scale industrial production. In addition, in the process, the catalyst will also have unavoidable loss.

The TS-1 of CN1639143A catalyzes the epoxidation of propylene and hydrogen peroxide, and adopts the reaction mode of autoclave, which still does not solve the problem of difficult separation of catalyst and product

In this method, the catalyst exists in a slurry state and needs to be separated from the product after the reaction. There is still the problem of difficulty in separating the catalyst from the product, and the loss of the catalyst will not only consume part of the catalyst, but also the catalyst powder will enter the product material and cause further damage. Side reactions, resulting in increased separation costs and affecting product quality