Preparation of salt solution useful for making nylon

• US 4,442,260 A
• Filed: 03/14/1983
• Issued: 04/10/1984
• Est. Priority Date: 03/14/1983
• Status: Expired due to Term

• Current Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Original Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Inventors: Larsen, Howland A.
• Primary Examiner(s): Ivy, C. Warren
• Application Number:
  US06/475,030
• Time in Patent Office: 393 Days
• Field of Search: 528/335, 524/845, 252/182, 260/501.2
• US Class Current: 524/845
• CPC Class Codes: C07C 209/68 from amines, by reactions not involving amino groups, e.g. reduction of unsaturated amines, aromatisation, or substitution of the carbon skeleton
• CPC Class Codes: C07C 211/12 1,6-Diaminohexanes
• CPC Class Codes: C07C 51/412 by conversion of the acids, their salts, esters or anhydrides with the same carboxylic acid part
• CPC Class Codes: C08G 69/28 Preparatory processes

Abstract

A process is described for making highly concentrated solutions of nylon salt in which the diamine is added in two portions, one before and one after a step in which water is evaporated from a solution of maximum solubility.

Claims

1. A process for making 66-nylon salt solution which comprises, in sequence

(a) preparing a water solution in which the solute phase contains 73.5-77.5% adipic acid and 22.5-26.5% hexamethylene diamine, by weight, at a temperature of 55°

-60°

C. in which the total solute concentration is 60-69% and the water concentration is 31-40%, and

(b) concentrating the solution by evaporating water until the solute comprises between 89 and 96%, by weight, and

(c) adding hexamethylene diamine until the hexamethylene diamine and adipic acid are in about stoichiometric proportions.