| 摘要 |
<p>The invention relates to a process for producing HPLC grade acetonitrile by the purification of crude acetonitrile which comprises the following steps ; -1) feeding crude acetonitrile containing acrylonitrile as an impurity and water into the upper portion of a first distillation column provided with an overhead reflux loop at a pressure of at least 1 at and distilling the crude acetonitrile in the presence of water; -2) distilling the first azeotrope in a second distillation column provided with a second overhead reflux loop, at a pressure of less than 1 at in order to separate the first azeotrope into a second bottom product containing water and a second acetonitrile/water azeotrope having a greater acetonitrile concentration than the first azeotrope; - 3) distilling the second acetonitrile/water azeotrope in a third distillation column provided with a third overhead reflux loop at a pressure greater than 1 at; - 4) passing the highly pure acetonitrile obtained as side stream through an acidic ion exchange resin layer with a view to further purify the highly pure acetonitrile, producing HPLC grade acetonitrile, wherein the reflux ratios in steps 1, 2 and 3 are kept higher than 2.7 to 1, higher than 2.2 to 1, and higher than 3.0 to 1 respectively.</p> |
