| abstract |
The present invention relates to UV absorber compounds of formula (I) wherein n is 1-3, R1 is a direct bond or a n-hydrocarbon residue which may contain a heteroatom and R2 is hydrogen, halogen, nitro, C1-8 alkyl, -8-alkoxy or C1-C8 alkenyloxy, and wherein the compounds have a yellowness of less than 0 and a sodium concentration of less than about 50 ppm. The invention further relates to a process for the preparation of the compounds of general formula (I) above, which comprises reacting purified thioacetic anhydride with an acylating compound selected from approximately stoichiometric amounts of carboxylic anhydrides and acyl halides, wherein the isatoic acid anhydride is extracted. HE |