be removed by distillation and the catalyst or its valuable constituents can be recovered from the residue e g by acid extraction as is customary in the oxo process having now generally described the invention a further understanding can be obtained by reference to certain specific examples which are provided herein for purpose of illustration only and are not intended to be limiting unless otherwise specified a 1308 g amount of crude i heptadecanol about 70 corresponding to 3 6 mol of i heptadecanol originating directly from the oxo process 414 g 3 0 mol of 4 hydroxybenzoic acid and 42 g of an acid aluminum hydrosilicate of the montmorillonite type montmorillonite ks from sudchemie ag are mixed under a nitrogen atmosphere in a 2 5 liter flask fitted with stirrer reflux condenser 0 5 u00b0 c and water separator and are stirred for about 30 minutes at room temperature in order to free the liquid phase of oxygen the mixture is subsequently heated at 170 u00b0 c while flowing a stream of nitrogen into the flask over a period of 3 hours 132 g of a two phase mixture are separated after cooling to 40 u00b0 c the reaction mixture is filtered through a filter press a 112 3 g amount of solid and 1365 5 g of filtrate are obtained the filtrate is distilled in two stages in a thin film evaporator the low boilers are first removed at u2212 170 u00b0 c 100 mbar giving a bottom product of 1247 1 g in a second pass the.