| abstract |
For the Contracting States : DE, FR, IT, NL, BE, CH, GB, SE, LI, LU) 1. 2,2'-Dihydroxy-5,5'-methylenedi-(p-toluene-sulphonic acid) and its salts. For the Contracting State : AT 1. Process for the preparation of 2,2'-dihydroxy-5,5'- methylenedi-(p-toluenesulphonic acid) and its salts, characterized in that a) m-cresol-6-sulphonic acid and/or its salts are reacted in an acid medium with formaldehyde and/or formaldehyde donors and, if desired, a resulting salt is converted into the free acid or into another salt, b) m-cresol-6-sulphonic acid and/or its salts are converted, in a basic medium, by means of form-aldehyde and/or formaldehyde donors into 4-hydroxymethyl-m- cresol-6-sulphonic acid and the latter is subjected in an acid medium to a condensation reaction with m-cresol-6-sulphonic acid and/or its salts and, if desired, a resulting salt is converted into the free acid or into a another salt, or c) m-cresol which is substituent in the 6-position by a detachable substituent is reacted, in an acid medium, with formaldehyde and/or formaldehyde donors to give a 5,5'-disubstituted 4,4'-dihydroxy-2,2'-dimethyl diphenylmethane, the substituents in the 5-position and 5'-position are split off and the product is sulphonated in an acid medium with sulphuric acid and/or an agent which splits off sulphonic acid groups and, if appropriate, a resulting salt is converted into the free acid or into another salt. |