Preparation method for synthesizing 3-methyl-3-butene-1-ol by using formaldehyde hemiacetal

Abstract

The invention relates to a method for synthesizing 3-methyl-3-butene-1-ol by using formaldehyde hemiacetal. The method comprises the following steps: pressurizing the formaldehyde hemiacetal to 12-18MPa under continuous operation conditions, and preheating to the temperature to 280 to 350 DEG C, wherein a supercritical state of the formaldehyde hemiacetal is reached; and rapidly mixing the formaldehyde hemiacetal with supercritical isobutene under the same pressure and temperature, and carrying out a supercritical reaction in a tubular reactor for 0.5-5 minutes. The reaction solution is cooled under reduced pressure and is detected after the isobutene is recovered, the conversion rate of the formaldehyde hemiacetal can be over 98 percent, and the selectivity of the 3-methyl-3-butene-1-ol can be over 98 percent. The reaction can be carried out under the supercritical conditions, the method has the advantages that the reaction time is obviously shortened, the reaction efficiency is greatly improved, byproducts are obviously reduced, and the method is green, environment-friendly, low in cost and suitable for industrial application.

Description

technical field [0001] The invention relates to a method for synthesizing 3-methyl-3-buten-1-ol by supercritical reaction of formaldehyde hemiacetal as raw material and isobutene, which belongs to the field of fine chemical industry. Background technique [0002] 3-Methyl-3-buten-1-ol (C 5 h 10 O, molecular weight: 86.03, CAS number: 763-32-6) is a colorless liquid, and is an important intermediate for the synthesis of polycarboxylate concrete water reducers, citral fragrances, vitamin products and pyrethroid pesticides. At present, the synthetic method of 3-methyl-3-butene-1-alcohol mainly contains following several kinds: (1) take 3-methyl-2-butene-1-alcohol (prenyl alcohol) as raw material, Synthetic by isomerization reaction; (2) take formaldehyde / paraformaldehyde and isobutylene as raw material, obtain 3-methyl-3-buten-1-alcohol by Prins condensation in the presence of acid-base catalyst; (3) formaldehyde and 3-methyl-3-buten-1-ol was synthesized by carbonyl-ene reac...

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Problems solved by technology

For example, there is no information on the disclosed product in Patent Document 1, and the productive rate of 3-methyl-3-buten-1-alcohol in Non-Patent Document 1 is only 31%, and in Non-Patent Document 2, the conversion rate of formaldehyde reaches 82%, and 3- 87% selectivity to methyl-3-buten-1-ol with low formaldehyde conversion

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