GB858238A - Process for the preparation of acylaminocarboxylic acids - Google Patents

Abstract

A process for the preparation of acylaminocarboxylic acids comprises reacting a lactam which contains 5 to 9 carbon atoms in the lactam ring with a free carboxylic acid, which contains at least 8 carbon atoms in the molecule in the ratio 1 to 10 mol of lactam per mol of carboxylic acid at temperatures between 150 and 300 DEG C. in the presence of an inert gas. The products of the reaction are represented by the general formula: <FORM:0858238/IV(b)/1> in which R is an organic, preferably a non aromatic hydrocarbon, residue which contains at least 7 carbon atoms, n is a whole number from 3-7 and x is a whole number not more than 10. Compounds with amino carboxylic acid residues in polyamide-like combination are formed primarily when the lactam is used in more than equivalent amounts relative to the carboxylic acid. Water-soluble salts of the products containing non-aromatic hydrocarbon residues with at least 8 e.g. 8-26, preferably 10-20 carbon atoms and in which x is not greater than 5 are whitening agents. Lactams specified include butyrolactam, valerolactam, and octanoic acid lactam and N-hydrocarbon substituents containing 1-3 carbon atoms may be present in the lactams. Carboxylic acids specified include caprylic, pelargonic, capric, undecylic, lauric, palmitic, stearic, oleic, linoleic, behenic acids resin or naphthenic acids, e.g. abietic acid diphenylcarboxylic, triphenylcarboxylic, alkyl or cycloalkyl, benzyl benzoic, benzyl naphthoic acids and substitution products, especially alkyl derivatives thereof and complete or partially ring hydrogenated derivatives thereof. Ethercarboxylic acids, e.g. those derived from glycolic acid, or by reaction of alcohols with halocarboxylic acid salts especially chloracetic acid salts in the presence of acid-binding agents may also be employed as starting materials. Inert gases mentioned include carbon dioxide, nitrogen and water vapour. Increased pressures may be employed in the process and small amounts of water may be added to the reactants. Some products may be purified by fractional crystallisation as distillation of the methyl esters. Examples relate to the production of acylaminocarboxylic acids by heating caprolactam with lauric acid (1-5) or stearic acid (6-9). In Example (1) the product may be recrystallised from ethanol and the crude or purified acid converted to a water-soluble salt by neutralisation with caustic soda or potash solution, or mono-, di-or triethanolamine and in Example (2) the product is converted to a salt by reaction with sodium, potassium or guanidine carbonate.