Verfahren zur kontinuierlichen Herstellung von Alkalisalzen der Nitrilotriessigsäure
1,224,043. Production of alkali metal salts of nitrilotriacetic acid. BADISCHE ANILIN & SODA-FABRIK A.G. 11 July, 1968 [12 July, 1967], No. 33093/68. Heading C2C. A process for the continuous production of alkali metal salts of nitrilotriacetic acid from alkali metal cyanide, formaldehyde and am...
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Zusammenfassung: | 1,224,043. Production of alkali metal salts of nitrilotriacetic acid. BADISCHE ANILIN & SODA-FABRIK A.G. 11 July, 1968 [12 July, 1967], No. 33093/68. Heading C2C. A process for the continuous production of alkali metal salts of nitrilotriacetic acid from alkali metal cyanide, formaldehyde and ammonia, comprises carrying out the reaction in at least two stages, wherein in a first stage alkali metal cyanide is reacted with formaldehyde in a stoichiometric or substantially stoichiometric ratio at temperatures of 50-200 C. and a pressure of 2 to 50 atmospheres gauge in the presence of excess ammonia to form a solution which contains predominantly aminoacetate, and treating the solution thus obtained after depressurizing to atmospheric pressure in a further stage or in several further stages whilst simultaneously removing ammonia with further amounts of alkali metal cyanide and formaldehyde at temperatures of 60-110 C. to effect conversion of the aminoacetic acid to nitrotriacetic acid. The different stages of the process are preferably effected in separate vessels and the reaction may be effected in the presence or absence of added base. The ammonia may be removed in the second and subsequent stages of the reaction by the passage of a gas which is inert under the reaction conditions, e.g. N 2 , O 2 or steam. Small amounts of by-products, e.g. aminoacetic acid and iminodiacetic acid salts, may also be formed. |
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