FORFARANDE FOR FRAMSTELLNING AV FLUORANDERIVAT

1338851 Preparing fluoran compounds NATIONAL CASH REGISTER CO 16 Aug 1972 [30 Aug 1971] 38133/72 Heading C4P Fluoran compounds of the general formulµ wherein each R is H or alkyl, R 1 is alkyl and n is 0 or an integer from 1-5 are prepared by reacting a benzophenone compound of general formula with a phenol derivative of the general formulµ in presence of concentrated sulphuric acid at 10-30‹ C. in a mole ratio of benzophenone: phenol derivative greater than 1 : 1, adjusting the reaction mixture to an alkaline pH and then continuing the reaction at 80-100‹ C. The preferred benzophenone : phenol derivative ratio range is 1À1 : 1 to 2 : 1. The product is isolated by water dilution, filtration water and then hexane washing and finally drying.