| 摘要 |
<p>Impurities such as an organic solvent and a volatile acid are efficiently removed from a liq., which is esp. an ester or ester mixt. obtd. by esterification. The liq. is first fed through a preheater (i) for heating by indirect heat exchange with a heat transfer fluid (HTF), and then via a pre-evaporator (2) to a plate column (3) followed by an evapn. and stripping column (4), which is indirectly heated via another HTF. At least the two columns (3,4) are operated at a reduced pressure; and the purified liq. ester is removed from the base (33) of column (4). The vapour formed in the pre-evaporator (2) is pref. subjected to progressive condensn. in column (3). Used e.g. for the removal of white spirit and heptanoic acid from a trimethylolpropane triheptanoate ester so the latter has a purity of 99.98%.</p> |
