Heteropolyacid catalyst, and preparation method and application thereof

Abstract

The invention discloses a heteropolyacid catalyst, and a preparation method and application thereof. The catalyst has the following formula: Mo12PaVbCucAdDeEfOg, wherein A represents at least one element of tungsten, silicon, iron, cobalt, zinc, lead, palladium and stibium; D represents at least one element of boron, arsenic, tellurium and cerium; E represents at least one element of potassium, rubidium and caesium; a equals to 0.1-0.3; b equals to 0.01-5; c equals to 0.01-5; d equals to 0.001-1; e equals to 0.01-2; f equals to 0.01-2; and g represents an atom ratio of oxygen needed for meeting valences of the components. The preparation method disclosed by the invention comprises the following steps of: (a) dissolving compounds of the corresponding elements respectively; (b) mixing the compounds and applying ultrasonic waves with the frequency of 10-180 kHz to the compounds at 30-90 DEG C for 0.1-3 hours, thereby preparing suspended dispersion size containing catalyst precursors of all the catalyst components; and (c) drying the suspended dispersion size to obtain the catalyst precursors, and roasting the catalyst precursors.

Description

technical field [0001] The invention relates to a catalyst for synthesizing methacrylic acid (MAA) from methacrolein (MAL) through a selective oxidation reaction and a preparation method of the catalyst. The catalyst prepared by the method of the invention not only has high reaction conversion rate, but also has high product selectivity. Background technique [0002] Catalysts for the synthesis of methacrylic acid (MAA) from methacrolein (MAL) by selective oxidation are known. For this selective oxidation catalyst, activity and selectivity are always a contradiction. An increase in activity often leads to a decrease in selectivity; an increase in selectivity often leads to a decrease in activity. However, catalysts must meet considerable activity and certain selectivity in order to meet the requirements of industrial scale-up production. For this reason, many methods have been proposed in the prior art to balance activity and selectivity. [0003] The method of producing...

AI Technical Summary

Problems solved by technology

The disadvantage of this method is that a large amount of water is used to dissolve molybdenum trioxide in the preparation process, so a large amount of energy is required to dry these compound-containing slurries in the subsequent process, resulting in a great consumption of energy

[0004] Chinese patent CN 1212302C proposes that ammonium paramolybdate, ammonium metavanadate and cesium nitrate are dissolved in a certain amount of water, and then mixed with other material precursor aqueous solutions such as phosphoric acid to prepare the method of phosphomolybdenum heteropolyacid catalyst. It has been controlled, but when the material slurry is formed, the liquid level stratification phenomenon will occur, and a large amount of sediment will be deposited at the bottom, resulting in uneven catalyst components, directly affecting the reaction performance of the catalyst, reducing the activity and selectivity of the catalyst, and shortening the life of the catalyst. Catalyst life

However, it was found that the use or non-use of ultrasonic dispersion technology had no significant effect on the reaction rate of methacrolein and the selectivity of methacrylic acid

Images