Published May 1981
This report includes five processes. One of these is a speculative process we have not evaluated before, straight distillation to recover isoprene from C5 by-product streams from ethylene plants. The other four processes (all in commercial operation) are updates of four of the seven processes presented either in PEP Report 28 or PEP Report 28A-I, an interim report issued in 1971. One of these processes, the most attractive economically, is the extraction of isoprene (primarily by extractive distillation with dimethylformamide) from C5 streams from ethylene plants. The other three routes are synthetic processes: isoprene from isobutylene and formaldehyde, isoprene from acetone and acetylene, and isoprene from amylenes.