Process for production of unsymmetrical dimethylhydrazine by nitrosation of dimethylamine and hydrogenation of the nitroso dimethylamine to the distillation of unsymmetrical dimethylhydrazine
AssigneeTeledyne McCormick Selph
InventorsDonald N. Thatcher, Yoshiyuki Arikawa
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Abstract
A process for production of unsymmetrical dimethylhydrazine from nitroso dimethylamine that is characterized as a completely closed system with respect to positive prevention of environmental contamination by waste nitrosodimethylamine. This process further provides a novel extraction step which also produces, as a solid by-product, potassium nitrate without nitrosodimethylamine contamination.
Claims13
A process for preparing unsymmetrical dimethylhydrazine by the catalytic hydrogenation of N-nitrosodimethylamine and recovering potassium nitrate as a by-product consisting essentially of the steps of:
- A. nitrosating an aqueous solution of dimethylamine by reaction with dinitrogen tetraoxide and potassium carbonate at a pressure from atomospheric to 50 psig and a temperature from -10.degree. C. to 40.degree. C. to produce an aqueous solution of N-nitrosodimethylamine and potassium nitrate and gaseous carbon dioxide;
- and,
- B. extracting all of said potassium nitrate from said aqueous solution by a liquid extraction at a temperature between 0.degree. C. to 30.degree. C. wherein methylene chloride is added as an extractive solvent to said aqueous solution, and withdrawing an aqueous solution of said potassium nitrate and a separate potassium nitrate-free stream of N-nitrosodimethylamine in solution with methylene chloride;
- and,
- C. hydrogenating the potassium nitrate-free stream of N-nitrosodimethylamine solution in the presence of a hydrogenation catalyst by reacting said stream with hydrogen at a pressure from 50-1000 psig and at a temperature from 50.degree.-90.degree. C. to produce an aqueous product solution containing unsymmetrical dimethylhydrazine;
- and
- D. distilling said product solution in the presence of an organic distillation base selected from the group consisting of diethanolamine, morpholine, diethylaminoethanol and dimethylamino ethanol, and taking off unsymmetrical dimethylhydrazine as a heart cut substantially free of water, N-nitrosodimethylamine, and said distillation base.
A process for preparing unsymmetrical dimethylhydrazine by the catalytic hydrogenation of N-nitrosodimethylamine which initially is in an aqueous solution with potassium nitrate, wherein crystalline potassium nitrate is recovered as a by-product, said process consisting essentially of:
- A. extracting all of said potassium nitrate from said initial acqueous solution by a liquid extraction at a temperature between 0.degree. C. to 30.degree. C. wherein methylene chloride is added as an extractive solvent to said initial aqueous solution and withdrawing an aqueous solution of said potassium nitrate and a separate solution of N-nitrosodimethylamine in solution with methylene chloride;
- and
- B. hydrogenation the potassium nitrate-free stream of N-nitrosodimethylamine solution in the presence of a hydrogenation catalyst by reacting said stream with hydrogen at a pressure from 50 to 1000 psig and at a temperature from 50.degree. C. to 90.degree. C. to produce an aqueous product solution containing unsymmetrical dimethylhydrazine, and;
- C. distilling said product solution in the presence of an organic distillation base selected from the group consisting of diethanolamine, morpholine, diethylamino ethanol and dimethylamino ethanol, and taking off unsymmetrical dimethylhydrazine as a heart cut substantially free of water, N-nitrosodimethylamine and said organic distillation base, and;
- D. recovering crystalline potassium nitrate from said withdrawn aqueous solution which also includes trace elements of N-nitrosodimethylamine by substantially separating out the water to create a slurry at a temperature above 300.degree. C. for a time sufficient to vaporize all water and trace elements of N-nitrosodimethylamine remaining in said slurry, and removing solid potassium nitrate as a by-product and venting all vaporized products to a thermal destructor wherein said vaporized N-nitrosodimethylamine is oxidized and thermally destroyed.
Dependencies are inferred from the claim text.