A kind of titanium silicon molecular sieve and its synthesis method and application and a kind of method of phenol hydroxylation

Abstract

The present invention relates to the field of molecular sieves, and specifically provides a titanium-silicon molecular sieve, a synthesis method and applications thereof. The synthesis method comprises: (1) hydrolyzing an organosilicon source, a titanium source and an alkali templating agent to obtain a mixture A, and carrying out first crystallization on the mixture A; and (2) mixing the crystallized material and titanium-silicon molecular sieve raw powder to obtain a mixture B, and carrying out second crystallization on the mixture B, wherein the solid content of the mixture B is 30-80 wt% with the use amount of the titanium-silicon molecular sieve raw powder. The invention further provides a phenol hydroxylation method. According to the present invention, the titanium-silicon molecular sieve prepared according to the method has advantages of high relative crystallinity, uniform particle size, high Ti content, large pore volume, and large external specific surface area.

Description

technical field [0001] The invention relates to a method for synthesizing a titanium-silicon molecular sieve, a titanium-silicon molecular sieve synthesized by the method, and an application of the titanium-silicon molecular sieve in phenol hydroxylation and a method for phenol hydroxylation. Background technique [0002] Titanium-silicon molecular sieve TS-1 is a new type of titanium-silicon molecular sieve with excellent catalytic selective oxidation performance formed by introducing transition metal element titanium into the molecular sieve framework with ZSM-5 structure. TS-1 not only has the catalytic oxidation effect of titanium, but also has the shape-selective effect and excellent stability of ZSM-5 molecular sieve. Since TS-1 molecular sieve can use non-polluting low-concentration hydrogen peroxide as an oxidant in the oxidation reaction of organic matter, it avoids the problems of complex oxidation process and environmental pollution, and has incomparable energy sa...

AI Technical Summary

Problems solved by technology

In the process of gelation, the hydrolysis conditions of the mixed solution of silicon ester and titanium ester are very strictly controlled, because the hydrolysis speed of the two does not match, the latter is higher than the former, and the addition of organic base at a slightly faster speed will produce irreversible titanium. These titanium polymers are difficult to enter the framework during the crystallization process, and most of them are mixed in the molecular sieve in the form of non-skeleton titanium. This part of titanium may not only block the pores, but also catalyze the decomposition of hydrogen peroxide, wasting raw materials

[0004] Since then, researchers have made many attempts and improvements to the synthesis methods of titanium-silicon molecular sieves, but the existing production methods still have problems such as low solid content, long production cycle, uneven distribution of titanium, and poor preparation repeatability; especially titanium-silicon When molecular sieves are used in catalytic oxidation reactions, there are generally problems such as large grains of titanium-silicon molecular sieves, low activity, and small grains, which are difficult to filter and separate.

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