Method for isolating N-phosphonomethylglycine
AssigneeShowa Denko K.K.
InventorsHideo Miyata, Toru Sasaki, Kohei Morikawa
Life of this patent
Estimating the term…
Abstract
The present invention provides a method for isolating N-phosphonomethylglycine which comprises adding an acid to precipitate salts from an aqueous solution of an alkali metal salt and/or an alkaline earth metal salt of N-phosphonomethylglycine solution to neutralize and adjust the same to a pH of 2.5 or higher, removing the precipitated salts, and adjusting the pH to 2.5 or lower to crystallize N-phosphonomethylglycine. N-phosphonomethylglycine is thus isolated and purified in high purity and good yield.
Claims20
A method for isolating N-phosphonomethylglycine which comprises adding an acid to precipitate salts from an aqueous solution of an alkali metal salt and/or an alkaline earth metal salt of N-phosphonomethylglycine at a pH of 2.5 or higher, removing the precipitated salts, and adjusting the pH to 2.5 or lower to crystallize N-phosphonomethylglycine.
A method for isolating N-phosphonomethylglycine which comprises adding an acid to precipitate at a pH of 2.5 or higher salts from an aqueous solution of an alkali metal salt and/or an alkaline earth metal salt of N-phosphonomethylglycine obtained by hydrolyzing N-phosphonomethylglycinonitrile with an alkali metal hydroxide and/or an alkaline earth metal hydroxide, removing the precipitated salts, and adjusting the pH to 2.5 or lower to crystallize N-phosphonomethylglycine.
A method for preparing and isolating N-phosphonomethylglycine which comprises reacting glycolonitrile, or formaldehyde and hydrogen cyanide in situ, with an aminomethylphosphonic acid in the presence of an alkali metal hydroxide and/or an alkaline earth metal hydroxide, hydrolyzing the reaction product to obtain an aqueous solution of an alkali metal salt and/or an alkaline earth metal salt of N-phosphonomethylglycine, adding an acid to precipitate salts from the aqueous solution at a pH of 2.5 or higher, removing the precipitated salts, and adjusting the pH to 2.5 or lower to crystallize N-phosphonomethylglycine.
A method for preparing and isolating N-phosphonomethylglycine which comprises reacting glycolonitrile with an aminomethylphosphonic acid in the presence of an alkali metal hydroxide and/or an alkaline earth metal hydroxide, hydrolyzing the reaction product to obtain an aqueous solution of an alkali metal salt and/or an alkaline earth metal salt of N-phosphonomethylglycine, adding an acid to precipitate salts from the aqueous solution at a pH of 2.5 or higher, removing the precipitated salts, and adjusting the pH to 2.5 or lower to crystallize N-phosphonomethylglycine.
Dependencies are inferred from the claim text.