GB584185A - Process for the manufacture of artificial tanning agents and products resulting therefrom - Google Patents

Abstract

Artificial tanning agents are prepared by cold-sulphonating phenol or its homologues in the presence of fatty alcohols, or ester of fatty alcohols, saturated or unsaturated, and then condensing the sulphonation product thus obtained with formaldehyde, or with urea and formaldehyde in acid solution. An alternative form of the invention comprises condensing the sulphonation product obtained as above with the condensation product of urea and formaldehyde in acid or alkaline solution, and finally partially neutralizing the products to a pH of 3. The preferred proportion of sulphonated phenol to aldehyde is two molecules of sulphonated phenol, less than one molecule of urea and one to two molecules of formaldehyde. The final neutralization may be carried out with sodium or potassium hydroxide, ammonia, or an organic salt of these bases, but preferably with a hydrate or oxide of a heavy metal such as chromium, manganese, aluminium or magnesium. In examples: (1) Oleum is added to a mixture of phenol and lauric alcohol melted together and cooled to 40 DEG C. The mixture is kept at room temperature for 24 hours and diluted with water, not allowing the temperature to rise. An aqueous solution of formaldehyde is then added. (2) To a sulphonated phenol prepared as in example (1) there is added an aqueous solution of urea followed by an aqueous solution of formaldehyde. (3) As in example (2), but using a melt of ortho-cresol and cetylic alcohol instead of lauric alcohol and phenol. (4) Oleum is added to a mixture of boric esters of cetylic alcohol and of oleic alcohol and xylenol. After sulphonation as in example (1) the product is treated with aqueous formaldehyde. (5) Xylenol is sulphonated as described in example (1) and to the sulphonation product so obtained there is added a condensation product of urea and formaldehyde, together with additional formaldehyde. Specifications 305,013, [Class 2 (iii)], 388,475, 425,037 and 456,741 are referred to.