Ammonia → Methyl 6-aminohexanoate

Participants

Reaction Steps

U.S. Pat. Nos. 4,730,041 and 4,731,445 use methyl 5-formylvalerate as a starting material and an alkanol as a solvent to produce caprolactam. First, methyl 5-formylvalerate is reacted with excess ammonia and hydrogen in the presence of an alkanol as a solvent and in the presence of a magnesium silicate-supported nickel catalyst at 40° to 130° C. under superatmospheric pressure to form methyl 6-aminocaproate. After the unreacted ammonia and hydrogen gas are removed, methyl 6-aminocaproate is converted into 6-aminocaproic acid and then formed to caprolactam by dehydrolyzation and cyclization or by direct de-alcoholization and cyclization. Although the process does not involve the hydrolyzation procedure of 5-formylvalerate, it suffers from the disadvantage that the starting material has a very low concentration (only 10%) and a great amount of alkanol should be separated and recycled.

Provenance & Evidence