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公开(公告)号：US5250728A
公开(公告)日：1993-10-05
申请号：US806567
申请日：1991-12-12
IPC分类号： C07C227/22 , C07C227/26 , C07C229/16 , C07C229/26 , C07D241/08 , C11D1/10 , C11D3/33 , C07C229/00
CPC分类号： C07D241/08 , C07C227/26 , C07C229/16 , C11D1/10 , C11D3/33
摘要： Synthesis of ethylenediaminetriacetic acid (ED3A) or its salts is disclosed. A salt of N,N'-ethylenediaminediacetic acid (ED2AH.sub.2) is condensed with formaldehyde to form a stable 5-membered ring intermediate. The addition of cyanide across this cyclic material forms ethylenediamine N,N'-diacetic acid-N'-cyanomethyl or salts thereof (mononitrile-diacid). The nitrile in aqueous solutions may be spontaneously cyclized to form 2-oxo-1,4-piperazinediacetic acid (3KP) or salts thereof, which is the desired cyclic intermediate. In the presence of excess base, salts of ED3A are formed in excellent yield and purity. Alternatively, the starting material is ED2AH.sub.a X.sub.b, where x is a base cation, e.g., an alkali or alkaline earth metal, a is 1 to 2, and b is 0 to 1 in aqueous solutions. The reaction mixture also can be acidified to ensure complete formation of carboxymethyl-2-oxopiperazine (the lactam) prior to the reaction. Formaldehyde is added, essentially resulting in the hydroxymethyl derivative. On the addition of a cyanide source, 1-cyanomethyl-4-carboxymethyl-2-ketopiperazine (mononitrile diacid) or a salt thereof is formed. Upon the addition of any suitable base or acid, this material may be hydrolyzed to 3KP. The addition of a base will open this ring structure to form the salt of ED3A.
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公开(公告)号：USH4H
公开(公告)日：1985-12-03
申请号：US732791
申请日：1985-05-10
申请人： Barry A. Cullen
发明人： Barry A. Cullen
IPC分类号： C07C255/25
CPC分类号： C07C255/25
摘要： Iminodiacetonitrile is prepared in a batch process comprising the addition of HCN to an acidified solution of hexamethylenetetramine while maintaining the resulting solution at a temperature of 20.degree.-90.degree. C. by cooling and at a pH of 5.5-6.5 by the addition of formaldehyde.
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