WHICH ROUTE TO 1,4-BUTANEDIOL

The introduction of polybutylene terephthalate (PBT) as one of the newest engineering thermoplastics has created world-wide interest in 1,4-butanediol, one of its comonomers. The standard commercial process for 1,4-butanediol is based on Reppe chemistry. This is the basis for processes employed by BASF and GAF, the two largest producers. In this technique, acetylene is condensed with formaldehyde via cupric acetylide catalysis to form 1,4-butanediol. Essentially every major feedstock has been proposed as an alternative to Reppe technology. Substantial work has been expended on systems based on propylene, maleic anhydride and butadiene. A description of the processes based on these feedstocks is followed by economic considerations and market predictions.