Adipic Acid via Butadiene Carbonylation

Published March 1985

This report evaluates a BASF process for adipic acid. The process is based on a two-stage carbonylation reaction of butadiene, carbon monoxide, and methanol to produce dimethyl adipate, which is then hydrolyzed to adipic acid. Eleven BASF patents, issued between 1977 and 1982, describe the new process in reasonable detail but probably do not include all process developments learned during subsequent pilot testing.

SRI's patent evaluation indicates the salient points of the new BASF process are as follows :

• The process has a reasonably high adipic acid yield (72%) based on butadiene. Dilute butadiene streams can be used.
• The adipic acid's high purity (99.9%) meets the purity requirements for nylon 6,6 fibers and resins.
• The recovery of the cobalt carbonylation catalyst is high, and catalyst activity can be maintained at a high level.
• The major by-products of the process are methyl valerate and the dimethyl esters of C₄ dicarboxylic acids, which could eventually find markets in a variety of applications. The by-products, which are produced in concentrated form, could also be incinerated if no markets develop.

SRI's evaluation indicates that the BASF process has an intrinsically lower raw material cost than the conventional process. If a market were to develop for the by-products, the evaluated process would have a further advantage. Assuming no by-product credit, the new process would be economically superior (on a product value basis) to the conventional process as long as the investment in a new plant does not exceed 150% of the capital investment required for a conventional plant.