Preparation of medicinal petroleum Jelly using local petroleum Waxes

Petroleum waxes are mainly derived from paraffinic crudes. These waxes must be removed from lubricant base oils through a dewaxing process to avoid affecting oil performance at low temperatures. The waxes themselves have uses. This paper describes successful attempts to select the optimum conditions for sulphonation and/or hydrogenation of local waxes to obtain medicinal macro‐ and microcrystalline waxes suitable for use in petroleum jelly blends that meet medicinal specifications. Deoiling was carried out to separate the oil from the wax samples. Concentrated and fuming sulphuric acids were used as sulphonating agents. Sulphonation processes were carried out at different temperatures, stirring speeds, and digestion times. The optimum sulphonation conditions, which give 0.007 UV absorbance at 290 nm and the highest yield, were achieved using 28% concentrated sulphuric acid. The optimum hydrogenation conditions were achieved using a Ni/Mo catalyst at 105°C and 60 bar for paraffin wax and 180°C and 100 bar for petrolatum, for 30 min for both types of waxes. Analysis and field trials of the blended petroleum jelly showed that these blends meet British Pharmacopoeia specifications.