Method for regenerating titanium-silicon molecular sieve catalyst

Abstract

The invention provides a catalyst used as a titanium-silicate molecular sieve in the process of preparing epoxide from olefin and hydrogen peroxide. The invention is characterized by comprising the following steps: washing with or without a small amount of methanol solvent; purging the catalyst cake with steam directly after reaction; extracting few organic matters absorbed in the catalyst; then stirring in a regenerating kettle and dropwise adding H2O2 with a certain concentration simultaneously; removing the organic matters and low polymers absorbed on the catalyst and in a pore path through oxidative decomposition; and finally, washing with a small amount of methanol or deionized water to remove the organic acid generated by oxidation on the surface of the catalyst. The regenerated catalyst can be circularly used for the epoxidation reaction of olefin to stably maintain the activity of the epoxidation reaction.

Description

technical field [0001] The invention relates to a method for regenerating the catalyst after the catalytic epoxidation reaction activity of the (zeolite) molecular sieve containing titanium atoms decreases or is deactivated. Background technique [0002] The emergence of iron-silicon molecular sieve catalytic materials has laid a foundation for the study of highly selective hydrocarbon oxidation reactions and the development of environmentally friendly processes. Titanium-silicon molecular sieve (TS-1) catalyst particles are small, generally only 0.2-2um, and it is a quasi-nanometer molecular sieve catalyst. Titanium silicate molecular sieve has unique catalytic properties for various organic oxidation reactions involving hydrogen peroxide, high product selectivity, mild reaction conditions, and environmental friendliness. It can catalyze epoxidation of alkenes, partial oxidation of alkanes, oxidation of alcohols, Hydroxylation of phenol and benzene, oxidation of cyclohexan...

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Problems solved by technology

[0005] The disadvantages of the above two schemes are: the shortcoming of the roasting regeneration method is that the processed catalyst must first be dried and completely dried, there are heating and cooling before and after roasting, the roasting temperature is high, and the energy consumption is high; During the transfer process, there is more solid dust and equipment investment increases

[0009] ①In the batch reactor, the regeneration process is a washing process, the washing temperature is as high as 120-150°C, and the pressure is 5-30 atmospheres. Due to the pressurized regeneration, the decomposition of hydrogen peroxide will cause potential safety hazards in the regeneration

[0010] ②In the continuous reactor, after the reaction is completed, there is no need to take out the catalyst from the reactor for regeneration treatment, so that the mixed solution containing aqueous hydrogen peroxide and alcohol passes through the catalyst bed in the continuous reactor at a certain rate. After the process is completed, let the alcohol or water flow in the reactor to clean the catalyst again. If the process is scaled up industrially, a large amount of hydrogen peroxide with a certain concentration will be washed through the catalyst bed at 25-200°C. There is a risk of hydrogen peroxide decomposition at higher temperatures. It is easy to cause the possibility of explosion, and at the same time, the amount of methanol used in the regeneration process is large, and the regeneration time is long

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