Preparation process of 2-ethyl hexenal and 2-ethyl hexanol

Abstract

The invention provides a preparation process of 2-ethyl-hexenal and 2-ethyl hexanol. The preparation process comprises the following steps: carrying out condensation reaction and dehydration reaction on butyraldehyde used as a raw material under the catalysis action of an alkaline catalyst in a first reactor and a second reactor which are connected in series, thus generating 2-ethyl hexenal, wherein the raw material butyraldehyde contacts the alkaline catalyst aqueous solution in the reactors in a counter-flow mode, and the fresh alkaline catalyst aqueous solution is added into the second reactor. In the process provided by the invention, the reaction occurring in the reactors is milder and has less possibility to generate by-products, therefore the raw material butyraldehyde for the condensation reaction can be directly introduced into an aldehyde condensation section for the condensation reaction as long as the content of n-butyraldehyde in the raw material butyraldehyde is not less than 90wt%; and furthermore, the alkali concentration of the fresh alkaline catalyst is improved, and the emission of the alkaline wastewater is reduced. In addition, crude 2-ethyl hexenal products containing a small amount of impurities, prepared by the preparation process, can be introduced into hydrogenation and rectification sections to prepare 2-ethyl hexanol products.

Description

technical field [0001] The invention relates to a preparation process of 2-ethylhexenal and 2-ethylhexanol, which belongs to the technical field of chemical industry. Background technique [0002] 2-Ethylhexanol (commonly known as octanol) is a colorless oily liquid with luster and fruity aroma. It has the largest output in oxo synthesis, accounting for more than half of the total oxo alcohol. 2-Ethylhexanol is mainly used in the production of the plasticizer dioctyl phthalate in the plastic industry and as a plasticizer for polyvinyl chloride resin. It has a good compatibility with most synthetic resins and rubbers used in industry. Solvent effect, high plasticizing efficiency, low volatility, good low temperature softness, good heat resistance and corrosion resistance. 2-Ethylhexanol is also used as a raw material for synthetic lubricants and antioxidants. It is also a solvent and a defoamer with good performance. It can be used in paper pulp sizing, photography, paint, ...

AI Technical Summary

Problems solved by technology

First of all, in the three reaction loops of the n-butyraldehyde condensation part, the first loop is passed into fresh alkaline catalyst aqueous solution, and in the first loop, the condensation reaction intensity is larger, the reaction is faster, and it is easier to generate polybutyraldehyde, polybutyraldehyde, Byproducts such as 2-ethyl-4-methylpentenal; secondly, the alkali concentration of the fresh alkaline catalyst aqueous solution is usually controlled as 2%, if the concentration of the fresh alkali solution is increased, side reactions are more likely to occur, and the condensation reaction itself will have Water is generated, therefore, there will be a large amount of dilute alkaline wastewater produced; again, the n-butyraldehyde content in the butyraldehyde raw material suitable for condensation requires ≥99.8%, so a rectification tower with more than 100 plates is required to remove the isobutyraldehyde Butyraldehyde impurity removal, high energy consumption, and complex process

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