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Process for the recovery of nicotinamide
| Details |
Inventors: Beschke, Helmut; Friedrich, Heinz; Muller, Klaus-Peter; Schreyer, Gerd;
Assignee: Deutsche Gold- Und Silber-Scheideanstalt vormals Roessler (Frankfurt, DE)
Primary Examiner: Rotman; Alan L.
Assistant Examiner:
Attorney, Agent or Firm: Cushman, Darby & Cushman
Nicotinamide is recovered from the reaction mixture resulting from the hydrolysis of nicotinonitrile at elevated temperature by converting the nicotinamide into a melt while removing the solvent. |
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DETAILED DESCRIPTION What is claimed is: 1.
A process for the recovery of nicotinamide from the reaction mixture resulting from the aqueous hydrolysis of nicotinonitrile at elevated temperature comprising converting the nicotinamide into a melt while removing the solvent at a temperature above 130.
degree.
C.
2.
The process of claim 1 including the step of directly cooling the melt to form solid nicotinamide.
3.
The process of claim 1 wherein the reaction mixture employ is one obtained by hydrolysis with alkali metal hydroxide at 110 to 250.
degree.
C.
4.
The process of claim 1 wherein the solvent is removed at a temperature between 130.
degree.
C.
and 200.
degree.
C.
5.
The process of claim 4 wherein the solvent is removed at 140 to 200.
degree.
C.
6.
The process of claim 5 wherein the solvent is removed at 150 to 180.
degree.
C.
7.
The process of claim 4 wherein the solvent at least in the final stages is removed at reduced pressure.
8.
The process of claim 7 wherein the terminal pressure for removal of the solvent is below 0.
2 bar.
9.
The process of claim 4 wherein the solvent is removed in a plurality of steps which the last step being carried out at a pressure of below 0.
2 bar.
10.
The process of claim 9 wherein the melt prior to the last solvent removal step has a solvent content of about 1 to 5 weight % and the last step of solvent removal is continued until the solvent content is below 0.
5 weight %.
11.
The process of claim 4 wherein the solvent removal is carried out at least in part in a falling film evaporator.
12.
The process of claim 4 wherein the solvent is removed from the melt until the melt has a solvent content of below 0.
5%.
Description:
The invention is directed to a process for the recovery of nicotinamide from the reaction mixture resulting from the hydrolysis of nicotinonitrile.
Several processes are known for the production of nicotinamide by the hydrolysis of nicotinonitrile.
The use of acid or alkaline acting materials is known.
As an acid substance there is used, for example, sulfuric acid (Helv
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