Method for preparing titanium-silicon molecular sieve and method for preparing cyclohexane oxime by using molecular sieve

Abstract

The invention provides a method for preparing a titanium-silicon molecular sieve with large particle diameter. The method comprises the following steps of: preparing dispersion liquid of a first-level crystalline particle molecular sieve; adding a flocculating agent and a coagulant aid into the dispersion liquid, and gathering the particles so as to form gathered particle solution; mixing the gathered particle solution and titanium-silicon template synthetic cement; and performing a hydrothermal process. The titanium-silicon molecular sieve prepared by the method has an average particle diameter of more than 5 microns; and when serving as a contact agent for preparing cyclohexane oxime, the titanium-silicon molecular sieve has high conversion rate and selection rate, and has the advantage of easiness for filtering and recycling.

Description

technical field

[0001] The invention relates to a method for preparing a titanium-silicon molecular sieve, in particular to a method for preparing a large-diameter titanium-silicon molecular sieve. Background technique

[0002] Crystalline titanium-silicon molecular sieve is a crystal form with MFI structure by introducing titanium atoms into the network structure of silica, also known as TS-1 molecular sieve. The molecular sieve is widely used as a catalyst in the oxidation reaction using hydrogen peroxide as an oxidant, and its preparation method has been disclosed in the US Patent No. 4410501. However, the molecular sieve particles produced by this method are about 0.2 microns. However, the 0.2-micron catalyst faces great challenges in chemical process applications (such as the use of cyclohexanone, ammonia, hydrogen peroxide and other reactants to prepare cyclohexanone oxime with titanium-silicon molecular sieves as catalysts). Therefore, subsequent inventors have devo...