Preparation method of catalyst for preparing methacrylic acid

Abstract

The invention provides a preparation method of a catalyst for preparing methacrylic acid. The preparation method comprises the following steps: coating catalyst powder containing heteropolyacid and / or salt of molybdenum, molybdenum and phosphor as active ingredient on a carrier, and then roasting the carrier, wherein inorganic binder is used in the coating process, the sol of oxide of Al, Si, Ti or mixture thereof is adopted as the inorganic binder, which is sodium ion type, non-sodium ion type stable sol or mixture thereof; the particle size of the oxide in the sol is 5-30nm, the content of the oxide is at least 5wt%, the particle size of the sol latex particle is at least 500nm, the density is 1.0-1.3g / cm <3>, the pH (potential of hydrogen) is 8.0-11.0; the adding amount of the sol is 2-30wt% of the amount of the active ingredient; the catalyst prepared according to the preparation method for preparing methacrylic acid has the advantages of high mechanical strength, low pulverization degree, high activity and high performance, and can be used for carrying out selective catalytic oxidation reaction on methylacrolein gas with molecular oxygen in a gas phase, so as to produce methacrylic acid.

Description

technical field [0001] The invention relates to the technical field of catalyst preparation, in particular to a preparation method of a catalyst for performing selective catalytic oxidation reaction of methacrolein gas in a gas phase with molecular oxygen to produce methacrylic acid. Background technique [0002] The preparation of methacrylic carboxylic acid by gas-phase selective catalytic oxidation of methacrolein is one of the common production methods in the chemical industry. The preparation of methacrylic carboxylic acid by selective catalytic oxidation of methacrolein in the gas phase is as follows: mix methacrolein, molecular oxygen gas and water vapor, and then enter a fixed-bed reactor equipped with a suitable catalyst reaction to make methacrylein Aldehydes form methacrylic acid. The catalysts used in this chemical reaction are generally heteropolyacid and / or salt catalysts, which are basically composed of heteropolyacids and / or salts prepared from molybdenum, v...

AI Technical Summary

Problems solved by technology

Considering the application conditions of the catalyst, the lack of mechanical strength will lead to the shedding of a large number of active components, which may cause problems in two aspects: on the one hand, after the catalyst is transported, loaded and other processes, the activity of the catalyst filled in the reactor The amount of components differs greatly from the theoretical value, which leads to the inability of industrial production to meet the requirements of the production process

The method disclosed in the above-mentioned patent documents can improve the mechanical strength of the catalyst to a certain extent, but the catalyst formed by coating the catalyst powder or forming aid on the support with heteropolyacid and / or salt as the active component can be There are few reports on improving the mechanical strength, high activity and high selectivity of catalysts