A titanium-silicon molecular sieve, its synthesis method and application, and a method for cyclic ketone oxidation

Abstract

The invention relates to the field of catalytic materials and in particular provides a titanium silicalite molecular sieve, a preparation method and application of the titanium silicalite molecular sieve. The titanium silicalite molecular sieve is composed of the following elements in percentage by mass: 0.01-10% of precious metals, silicon, 0.01-10% of titanium and oxygen, wherein the I960 / I550 value is 0.5-0.9; the U480 / U330 value is 0.5-5; the N-116 / N-112 value is 0.01-0.2; and the particle size is 0.5-5 microns. The invention further provides a cyclic ketone oxidation method. The cyclic ketone oxidation method comprises the following step: contacting cyclic ketone, an oxidizing agent and a catalyst, wherein the catalyst contains the titanium silicalite molecular sieve disclosed by theinvention. Compared with the prior art, the titanium silicalite molecular sieve disclosed by the invention has the advantages that diffusion of the reactants and product is facilitated in an oxidationreaction, so that oxidative activity is fully achieved, and the selectivity is improved. For example, when applied to a reaction in which ring molecules, particularly cyclic ketone molecules, participate or are produced, the titanium silicalite molecular sieve can achieve excellent catalytic effects. Moreover, filtration and separation of the catalyst after the reaction can be further facilitated, and industrialized application is easily realized.

Description

technical field [0001] The invention relates to a titanium-silicon molecular sieve, its synthesis method and application, and a method for oxidizing cyclic ketones. 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 saving, economy and environment in traditional oxidation systems. It has the advantages of friendliness and good reaction selectiv...

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 harsh, because the hydrolysis rate of the two does not match, the latter is higher than the former, and the addition of organic base is slightly faster, resulting in irreversible titanium polymerization. These titanium polymers are difficult to enter the framework during the crystallization process, and 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

When the organic silicon source is used, the solid content in the modified airtight container is mostly below 20%, generally around 10%, which seriously affects the production efficiency

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

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