Lactam dehydration method
AssigneeRhodia Fiber & Resin Intermediates
InventorsGerald Bocquenet, Yves Courtemanche, Patrick Houssier
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Abstract
The present invention relates to a process for separating the water from an aqueous lactam solution. It applies more particularly to a mixture resulting from the reaction between an aminonitrile and water (this reaction also being called cyclizing hydrolysis). The subject of the invention is a process for separating the water from an aqueous lactam solution, which process is economical both from the standpoint of the investment necessary for its implementation and from the standpoint of the operating cost.
Claims10
A process for separating water from an aqueous lactam solution, consisting essentially of:
- distilling the aqueous lactam solution in a first distillation column while maintaining a temperature at the bottom of the column less than or equal to 160° C. and at an absolute pressure of 50 millibars to 200 millibars, distillate recovered from the top of the column having been condensed at a temperature of 30° C. to 60° C. using a coolant;
- forwarding the lactam solution remaining at the bottom of the first distillation column to a second distillation column and maintaining a temperature at the bottom of the second distillation column less than or equal to 160° C. and at a pressure of 10 millibars to 45 millibars;
- recovering water, containing traces of lactam, at the top of the second column, as vapor at a temperature greater than or equal to 70° C.
Dependencies are inferred from the claim text.