Published November 1977
The principal reason for preparing this supplementary report on polybutylene terephthalate (PBT) and 1,4-butanediol (l,&BD) was to evaluate some of the new routes to 1,4-butanediol that are being investigated by some companies. Four new routes were evaluated. Two of the routes start with propylene; one route starts with butadiene; and the last route starts with n-butane.
The main commercial route for 1,4-BD starts with acetylene and formaldehyde (aqueous). This process was evaluated in our initial report on this subject (issued in May 1975). We have updated the estimated capital and production costs for this process and have also evaluated a new version of the process. With regard to PBT, we have evaluated continuous processes for making low molecular weight PBT (Mh = 22,000) and high molecular weight PBT (MN = 44,000) . We have also updated the costs for making low molecular weight PBT O$ = 22,000) by the batch process presented in our initial report on this subject.
Patents on PBT, 1,4-BD, and related subjects are reviewed in this report. A short section on the status of the industry is included, and a section on the basic chemistry of the processes of interest is presented.
