US EPA

9087873 

Journal Article 

The Solvent-Index of Refraction Method of Determining Oil in Wax 

Wilson, RE; Wilkin, RE 

1924 

0 

Industrial & Engineering Chemistry
ISSN: 0019-7866 

16 

1 

9-12 

English 

10.1021/ie50169a003 

This report describes a method developed in the laboratories of the Standard Oil Company (Indiana) for determining the oil content of paraffin wax. It is believed that this should supplant the present press method for “oil and moisture,” which has proved inaccurate and unsatisfactory. The new method consists essentially in dissolving a 5-gram wax sample in ethylene dichloride, cooling to about 0° F., filtering off the wax, washing, and evaporating the solvent from the filtrate plus washings. This leaves a residue containing all the oil and the small amount of low melting wax which is soluble even at 0° F. The amount of oil present therein is determined by adding enough of a special solvent to dissolve the residue and measuring the index of refraction, the corresponding oil content being determined by reference to a predetermined curve given in this paper. The method gives good checks on samples containing known amounts of oil, and seems to be quite satisfactory as far as it has been tried on oil and wax from Midcontinent crude. It should, however, be checked up in other laboratories with wax and oil made from other crudes. While the method is not as simple as might be desired, attempts to simplify it further have not been successful. Its accuracy is certainly far superior to that of the press method. The new method was used to show up the magnitude and sources of the errors in the ordinary press method by determining the amount of oil and wax contained in the residual wax cake and in the cloths and the blotting papers used in that method. These tests showed that the error in the press method may readily amount to as much as 2 per cent of oil on samples containing 2 or 3 per cent oil. © 1924, American Chemical Society. All rights reserved.