20 so 3 in several stages 7 of oleum being used at each stage treatment was carried out until the treated oils achieved the specifications in accordance with dab vii the results are shown in table ii table ii______________________________________ white oil i ii iii______________________________________charge materialextinction at 275 nm 0 5 cm 9 6 18 6 27 6de aromatizationv feed v resin cycle 10 0 5 0 2 5extinction at 275 nm 0 5 cm after de aromatization 0 75 sup 1 0 75 sup 1 0 75 sup 1treatment with 20 strength oleum 3 u00d7 7 4 u00d7 7 5 u00d7 7 extinction at 275 nm 0 5 cm after oleum treatment 0 41 0 48 0 69______________________________________ sup 1 result after 5th cycle production of high purity paraffinum durum according to the dab vii deutsche arzneibuch vii german manual for pharmacists and pharmaceutical industry charge material slack wax from the solvent neutral oil of the sae class 5 pretreated with 0 5 by weight of tonsil 2 to 3 by weight of oil content the average charge for 10 cycles amounted per cycle of 14 kg of pure paraffin kg of resin the charge material and end product has the analytical data shown in table iii table iii______________________________________ charge material purified paraffin______________________________________sulphur ppm 300 20ext at 275 nm 2 cm cuvette 0 5 g of paraffin in 50 1 8 0 25 ml of isooctane dabvii specifications ______________________________________ the maximum extinction of 0.