A kind of methanol oxidation to formaldehyde iron molybdenum catalyst and its preparation and application

Abstract

The invention relates to a preparation method and application of an iron-molybdenum catalyst for methanol oxidation to formaldehyde. The preparation of the iron-molybdenum catalyst takes metallic iron, organic acid and molybdenum acid as raw materials. First, the metallic iron reacts with the organic acid to generate the corresponding organic acid iron With hydrogen, then react molybdic acid with organic acid iron to generate iron molybdate and corresponding organic acid. Iron molybdate precipitation is the main active component of iron molybdenum catalyst, which can be separated from the preparation system by simple filtration. Then mix the ferric molybdate and molybdic acid aqueous solution according to different atomic ratios of molybdenum and iron, and the obtained slurry is aged, and then filtered to obtain a filter cake; the filter cake can be obtained by drying, pulverizing, molding and roasting, which can be used for methanol oxidation Iron-molybdenum catalyst for formaldehyde production. The organic acid produced in the above preparation process can react with metallic iron again, so as to realize the recycling of the organic acid in the preparation system, and the only by-product is hydrogen, which also has high economic value.

Description

technical field [0001] The invention belongs to the field of preparation of novel catalytic materials, in particular to a novel catalyst for the oxidation of methanol to formaldehyde iron molybdenum (MoO 3 -Fe 2 (MoO 4 ) 3 ) preparation method. Background technique [0002] As a basic chemical raw material, formaldehyde is widely used in many fields such as chemical industry, materials, and medicine. In the existing industrial production of formaldehyde in China, methanol oxidation process is the main method. According to the type of catalyst used, it is divided into "silver method" and "iron molybdenum method". Compared with the "silver method", the "iron-molybdenum method" production device has the advantages of large production capacity, low methanol unit consumption, long service life of the catalyst, high concentration of formaldehyde can be produced, and the environment is more friendly. Therefore, in recent years, newly built and expanded formaldehyde plants als...

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Problems solved by technology

CN 1044339 C, CN100413584C, US3978136, US4420421, US 4829042, etc. have carried out the preparation of iron-molybdenum catalysts by co-precipitation method, although the activity is good enough and the strength meets the requirements of iron-molybdenum catalysts for methanol oxidation to formaldehyde, but there are There is a large amount of acid waste water, and the waste gas containing ammonia nitrogen will also be generated during the roasting process

Although CN 102240554 B reported a pollution-free preparation process of catalysts for methanol oxidation by iron-molybdenum method, it claimed that the whole preparation process had no "three wastes" emissions, but used iron pentacarbonyl, nonacarbonyl diiron, dodecacarbonyl triiron, etc. Raw materials, resulting in high catalyst preparation costs, difficult to achieve large-scale preparation, limiting its further industrial application

[0004] At present, the existing domestic iron-molybdenum method catalysts generally have the disadvantages of producing a large amount of waste water and waste gas during the preparation process, which is not environmentally friendly, and also increases the preparation cost of the catalyst.

[0005] In summary, the existing iron-molybdenum-based catalysts for methanol oxidation to formaldehyde are mostly prepared by coprecipitation method, which cannot solve the problem of producing a large amount of waste water and waste gas during the preparation process.

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