| abstract |
PURPOSE:To suppress the decomposition reaction of urea, and stabilize urea for a long period, by adding one or more kinds of compounds selected from neutral amino acids, acidic amino acids and the alkali metal salts of acidic amino acids to an aqueous solution of urea. CONSTITUTION:An aqueous solution of urea is added with one or more compounds selected from neutral amino acids, acidic amino acids (e.g. glycine, alanine, serine, valine, threonine, aspartic acid, glutamic acid, etc.) and alkali metal salts (e.g. sodium salt, potassium salt, lithium salt, etc.) of acid amino acids. A larger amount of amino acid gives higher suppressing effect to the decomposition of urea, however, excessive addition of the acid causes the degradation of the amino acid itself resulting in the discoloration and emission of ill odor, etc. Accordingly, the amount of the amino acid is selected according to the amount of urea to be stabilized, the condition and period, etc. of storage, etc. |