| 摘要 |
Tetrahydrofuran is recovered by a two stage distillation procedure from a crude hydrogenation product resulting from vapor phase hydrogenation of diethyl maleate and containing water, ethanol and a minor amount of n-butanol, and possibly also dissolved hydrogen, in addition to butane-1,4-diol, gamma-butyrolactone and "heavies" such as diethyl ethoxysuccinate. In the first distillation stage, conveniently operated substantially at atmospheric pressure, ethanol, water, and tetrahydrofuran are recovered as overhead product, are condensed to separate the condensible components from a hydrogen stream which can be vented, and then redistilled in the presence of a molar excess of a hydroxylic solvent containing at least two hydroxyl groups, such as butane-1,4-diol, in a second distillation zone. Pure tetrahydrofuran is recovered as overhead product from the second distillation zone, while the bottom product therefrom is stripped in a third distillation zone of tetrahydrofuran, ethanol and water which are recycled to the first distillation zone and the stripped bottom product is recycled to the second distillation zone.
|
