BUTANEDIOL (HO-(CH₂)₄-OH)

  1,4-Butanediol from maleic anhydride is discussed later in this chapter. An alternative route for the diol is through the acetoxylation of butadiene with acetic acid followed by hydrogenation and hydrolysis. The first step is the liquid phase addition of acetic acid to butadiene.

The acetoxylation reaction occurs at approximately 80°C and 27 atmospheres over a Pd-Te catalyst system. The reaction favors the 1,4-addition product (1,4-diacetoxy-2-butene). Hydrogenation of diacetoxybutene at 80°C and 60 atmospheres over a Ni/Zn catalyst yields 1,4-diacetoxybutane. The latter compound is hydrolyzed to 1,4-butanediol and acetic acid:

Acetic acid is then recovered and recycled. Butanediol is mainly used for the production of thermoplastic polyesters.