title: Stability of water-soluble carbodiimides in aqueous solution.
abstract: A dimethylbarbituric acid reagent has been used to follow the kinetics of loss of two water-soluble carbodiimides, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and the structurally related 1-ethyl-3-(4-azonia-4,4-dimethylpentyl) carbodiimide (EAC), in aqueous solution as a function of pH and added chemical reagents. In 50 mM 2-(N-morpholino)ethanesulfonic acid at 25 degrees C, EDC has t1/2 values of 37, 20, and 3.9 h at pH 7.0, 6.0, and 5.0, respectively, while the corresponding values for EAC are 12, 2.9, and 0.32 h. Iodide, bromide, or chloride, at 0.1 M, has very little or no effect on carbodiimide stability. However, 0.1 M glycine methyl ester or 0.1 M ethylenediamine causes a significant increase in the rate of loss of EAC and EDC, while the presence of 0.1 M phosphate, 0.1 M hydroxylamine, or 0.01 M ATP decreases the half-lives to less than or equal to 0.4 h at all pH values.
authors.affiliation: Department of Chemistry, College of Wooster, Ohio 44691.
authors.forename: M A
authors.initials: MA
authors.lastname: Gilles
authors.forename: A Q
authors.initials: AQ
authors.lastname: Hudson
authors.forename: C L
authors.initials: CL
authors.lastname: Borders
mesh_terms: D000476:Alkanesulfonates; D017738:Alkanesulfonic Acids; D002234:Carbodiimides; D005022:Ethyldimethylaminopropyl Carbodiimide; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D009025:Morpholines; D012996:Solutions; D014867:Water
chemical_list: D000476:Alkanesulfonates; D017738:Alkanesulfonic Acids; D002234:Carbodiimides; D009025:Morpholines; D012996:Solutions; D014867:Water; C004550:2-(N-morpholino)ethanesulfonic acid; C044568:1-ethyl-3-(4-azonia-4,4-dimethylpentyl)carbodiimide; D005022:Ethyldimethylaminopropyl Carbodiimide