Patent ID: 9115067
Filing Date: 2015-08-25
Classification: C07C

Abstract:
1. A continuous process for producing acrolein, the process comprising: (a) feeding an initial gas stream comprising an oxygen source, and a propylene source to a reactor comprising a catalyst under conditions such that propylene is oxidized to produce a reaction effluent gas stream, the reaction effluent gas stream comprising acrolein, oxygen, propylene, carbon monoxide, carbon dioxide, acrylic acid, acetic acid, water, and acetaldehyde; (b) feeding the reaction effluent gas stream to the bottom section of a first separation device, the condensable portion of the reaction effluent gas stream being condensed in the first separation device to provide an aqueous liquid stream and a recycle gas stream, the condensable portion of the reaction effluent gas stream becoming the aqueous liquid stream comprising acrolein, acrylic acid, acetic acid, water and acetaldehyde, the non-condensable portion of the reaction effluent gas stream becoming the recycle gas stream comprising oxygen, propylene, propane, carbon dioxide, and carbon monoxide; (c) feeding a portion of the recycle gas stream to the reactor of step (a); (d) feeding the aqueous liquid stream to a second separation device that fractionates the aqueous liquid stream into a low-boiling point impurity stream, an acrolein stream, and a liquid recycle stream, the low-boiling point impurity stream comprising acetaldehyde, the acrolein stream comprising substantially pure acrolein, and the liquid recycle stream comprising water, acetic acid, and acrylic acid; and (e) feeding a portion of the liquid recycle stream to the top of the first separation device of step (b), the liquid recycle stream comprising from about 20% to about 30% acrylic acid by weight.