Method for producing benzaldehyde by oxidizing dibenzyl ether by air

Abstract

The invention discloses a method for producing benzaldehyde by oxidizing dibenzyl ether by air, comprising the following steps: feeding the dibenzyl ether produced in the benzaldehyde working section into a dibenzyl ether head tank, carrying out the benzaldehyde pilot production after the liquid level is more than 60% of the height of the dibenzyl ether head tank; adding material into an electric heating reactor from the dibenzyl ether head tank until the liquid level is 80% of the height of the electric heating reactor, and heating to increase temperature; obtaining the water in the dibenzyl ether by steaming, and pouring the water removed by steaming into the benzaldehyde working section; after finishing obtaining the water by steaming, increasing the temperature of the electric heating reactor so that the oil-phase material in a return pipe reflows; introducing air into the electric heating reactor, decreasing the temperature of the electric heating reactor along with reaction; stopping heating when the temperature of the electric heating reactor decreases to 200-210 DEG C; stopping introducing air when the temperature of the electric heating reactor continuously decreases to 190-200 DEG C; pumping the material in the electric heating reactor into a rectifying reactor under the vacuum condition; obtaining light components by steaming by a rectifying tower, and performing secondary refining on the light components via recycling; obtaining the finished product which is the benzaldehyde by steaming, putting the benzaldehyde into a barrel, and packaging; obtaining heavy components by steaming, and performing secondary refining on the components via recycling; removing slag; and analyzing the finished product which is the benzaldehyde by using the gas chromatography. The benzaldehyde is colorless and transparent, and has the fragrant bitter almond flavor.

Description

technical field [0001] The invention belongs to the technical field of chemical industry and relates to a method for producing benzaldehyde, in particular to a method for producing benzaldehyde by air oxidation of dibenzyl ether. Background technique [0002] At present, there are many ways to produce benzaldehyde in the industry. The toluene oxidation method produces benzaldehyde, and the by-products of the production process are more benzoic acid and benzyl alcohol. The production cost is high; the leftovers of benzyl chloride are produced by acid and alkali hydrolysis Benzaldehyde, the product benzaldehyde contains trace amounts of organic chlorine, which limits the scope of use of benzaldehyde; the traditional method of producing benzaldehyde from benzyl alcohol leftover dibenzyl ether is nitric acid catalytic oxidation, which is cumbersome to operate, high in cost, and easily generates nitrogen-containing by-products. product etc. Contents of the invention [0003] T...

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Problems solved by technology

[0002] At present, there are many ways to produce benzaldehyde in the industry. The toluene oxidation method produces benzaldehyde, and the by-products of the production process are more benzoic acid and benzyl alcohol. The production cost is high; the leftovers of benzyl chloride are produced by acid and alkali hydrolysis Benzaldehyde, the product benzaldehyde contains trace amounts of organic chlorine, which limits the scope of use of benzaldehyde; the traditional method of producing benzaldehyde from benzyl alcohol leftover dibenzyl ether is nitric acid catalytic oxidation, which is cumbersome to operate, high in cost, and easily generates nitrogen-containing by-products. product etc.

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