2,5-Di:methyl-hexane-2,5-di:ol continuous prodn. from tert. butanol - by oxidative dimerisation in two phase system with vigorous stirring, using aq. phase with specified density to facilitate phase sepn.

摘要

In the continuous prodn. of 2,5-dimethyl-hexane-2,5-diol (I) from t-BuOH by oxidative dimerisation in the presence of Fe2+ ions, H2O2 and acid, the reaction is carried out in a 2-phase system with an organic phase (II) and an aq. phase (III), with vigorous stirring, (III) being kept at a density of 1.2-1.4 g/cc. The prod. mixt. is discharged continuously, the phases are sepd. and (I) is sepd. from (II). (III) is kept at a density of 1.30-1.3.5 g/cc by adding salts, pref. sulphates, esp. solids (partly) obtd. in working up (II). (II) has a density of 0.7-0.8 g/cc. The H2O2:t-BuOH molar ratio if 1:(10-30), pref. 1:10-12). Reaction is carried out in the presence of H2SO4 and the wt. ratio of Fe2+:Fe3+ ions is 1:(8-10). Phase sepn. is carried out in packed sedimentation vessels. After sepn., (III) is subjected to cathodic redn. to regenerate the Fe2+ ions and (partly) recycled. Unreacted t-BuOH from (II) is recycled.