Method of producing anhydrous formaldehyde through oxygen-free dehydrogenation

Abstract

The invention relates to a method of producing anhydrous formaldehyde through oxygen-free dehydrogenation. A copper based catalyst is employed in the method and is arranged in a quartz reaction tube, wherein the quartz reaction tube is placed in a fixed bed reactor. Before reaction, at a certain temperature, the copper based catalyst is pre-reduced with methanol or hydrogen. Under normal pressure, the methanol is fed through a constant-flux pump with inert gas as a carrier gas to carry out a reaction at 400-700 DEG C, wherein the methanol is subjected to oxygen-free dehydrogenation to obtain formaldehyde. The copper based catalyst includes, by mass, 1-20 parts of copper, 100 parts of a dealuminated molecular sieve carrier, and 0-20 parts of a co-catalyst. Chromatography detection proves that methanol conversion is 45-99% and methanol selectivity is 30-95%. The catalyst is a copper based catalyst supported on chemically-dealuminated molecular sieve. The catalyst integrates both high specific surface area of the carrier molecular sieve and high activity of the copper based catalyst, and has high catalytic activity and thermal stability, less generation of side products and simple preparation process.

Description

technical field [0001] The invention belongs to the field of preparing anhydrous formaldehyde, in particular to a method for preparing anhydrous formaldehyde through anaerobic dehydrogenation. Background technique [0002] Formaldehyde is an important organic chemical raw material, which can be used to produce thermosetting resins such as phenolic resin and melamine resin, as well as various chemical products such as urotropine and 1,4-butanediol. Formaldehyde is also a synthetic dye, pesticide, fine and An important raw material for specialty chemicals. [0003] At present, methanol oxidation is generally used in industry to prepare formaldehyde. The produced formaldehyde contains a large amount of water, and the vapor pressure of formaldehyde aqueous solution is low, and formaldehyde and water can easily form an azeotrope. Therefore, formaldehyde is separated and purified. Very difficult, resulting in large energy consumption and high cost. In recent years, there is an i...

AI Technical Summary

Problems solved by technology

[0007] The significance of the present invention is to overcome the shortcomings of the catalysts currently used in the preparation of anhydrous formaldehyde, such as: the distribution of copper particles in the copper-based catalyst is uneven, the particles are large, the active surface area is small, and the activity is low; the modified molecular sieve catalyst acid Alkalinity is difficult to control, and there are many by-products; the catalytic activity of traditional carbonate or bicarbonate is relatively inert, and the reaction temperature is generally higher than 700°C