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US 4,069,257 AGranted
Process for preparing 2-acetyl-3-methyl-1,3-butadiene
AssigneeBayer Aktiengesellschaft
InventorsReinhard Lantzsch, Dieter Arlt
Life of this patent
Estimating the term…
Abstract
2-ACETYL-3-METHYL-1,3-BUTADIENE IS PREPARED BY THERMALLY DECOMPOSING 2-METHYL-3-HYDROXYMETHYL-PENT-1-EN-4-ONE OR ITS CARBOXYLIC ACID ESTERS.
Claims6
A process for preparing 2-acetyl-3-methyl-1,3-butadiene which comprises:
- A. contacting mesityl oxide with formaldehyde in the presence of 0.1 to 10 mol percent of a bicyclic amidine per mol of mesityl oxide whereby to obtain 2-methyl-3-hydroxymethyl-pent-1-en-4-one;
- and B. heating said 2-methyl-3-hydroxymethyl-pent-1-en-4-one at 300.degree. to 600.degree. C until it decomposes.
A process for preparing 2-acetyl-3-methyl-1,3-butadiene which comprises:
- A. forming 2-methyl-3-hydroxymethyl-pent-1-en-4-one by contacting mesityl oxide with formaldehyde in the presence of a catalytic amount of a bicyclic amidine;
- B. contacting said 2-methyl-3-hydroxymethyl-pent-1-en-4-one with a carboxylic acid, carboxylic acid chloride, carboxylic acid anhydride or carboxylic acid ester whereby to form the carboxylic acid ester of 2-methyl-3-hydroxymethyl-pent-1-en-4-one;
- and
- C. heating said carboxylic acid ester of 2-methyl-3-hydroxymethyl-pent-1-en-4-one until it decomposes.
1 more element
A process according to claim 3 wherein said 2-methyl-3-hydroxymethyl-pent-1-en-4one is contacted with formic acid ester, an acetic acid ester, a propionic acid ester or a benzoic acid ester to form the corresponding carboxylic acid ester.
A process for preparing 2-acetyl-3-methyl-1,3-butadiene which comprises:
- A. contacting mesityl oxide with formaldehyde in the presence of 0.1 to 10 mol percent of a bicyclic amidine per mol of mesityl oxide whereby to obtain 2-methyl-3-hydroxymethyl-pent-1-en-4-one;
- and
- B. heating said 2-methyl-3-hydroxymethyl-pent-1-en-4-one in the presence of an acid or basic catalyst until it decomposes.
Dependencies are inferred from the claim text.