Sulfonated ligno-aminodicarboxylates and process for making same
AssigneeReed Lignin, Inc.
InventorsStephen Y. Lin, Lin H. Hoo
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Abstract
Disclosed herein are sulfonated ligno-aminodicarboxylic acid and the salts thereof of the formula ##STR1## wherein X is an alkali cation, such as sodium, potassium, lithium, and ammonium, and Lignin denotes the polymeric sulfonated lignin material derived from commercial pulping of wood, straw, corn stalks, bagasse and the like. The dicarboxylic acid is made by a three-step process: (1) amination with ammonia and formaldehyde; (2) cyanomethylation with formaldehyde and sodium cyanide; and (3) hydrolysis of nitrile to carboxylic acid. The sulfonated ligno-aminodicarboxylic acid and its salts are useful as metal complexing agents.
Claims16
As a composition of matter, a sulfonated lignoaminodicarboxylate comprising a reaction product of a sulfonated lignin material containing 2 to 8 percent by weight of combined organic sulfur, and about 0.5-3 millimoles of ammonia, about 1.5-9 millimoles of formaldehyde, and about 1-6 millimoles of sodium cyanide, per gram of lignin in said material, and of the general formula ##STR4## wherein X is an alkali metal or ammonium cation, and Lignin is a polymeric sulfonated lignin material.
In a method for production of a ligno-aminocarboxylate, the steps comprising:
- (1) forming an aqueous reaction mixture of a sulfonated lignin material, about 0.5-3 millimoles of ammonia and about 0.5-3 millimoles of formaldehyde, per gram of said sulfonated lignin, and reacting the mixture at a pH of about 10.5 to 11.5 at about 50.degree. C. to 75.degree. C. for about 4 to 6 hours to form a lignin Mannich amine;
- (2) reacting said lignin Mannich amine with about 1-6 millimoles of formaldehyde and about 1-6 millimoles of sodium cyanide per gram of sulfonated lignin at about 25.degree. C. to 70.degree. C. for about 1 to 10 hours to form a lignin nitrile;
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- (3) hydrolyzing said lignin nitrile to ligno-aminodicarboxylate by heating the lignin nitrile solution at an initial pH above about 12 and at a temperature of about 90.degree. C. to 100.degree. C.
Dependencies are inferred from the claim text.