Influence of structural group composition of solid hydrocarbons on their physicomechanical properties

Information on the physicomechanical properties of the solid hydrocarbons of petroleum is of great practical importance in predicting the behavior of paraffin waxes and microcrystalline waxes in various fields of application. In the reported experiments, the petrolatum fraction was separated from Volgograd crudes by the successive use of chromatography on silica gel, adduct formation with urea, and fractional crystallization from MEK (benzene)toluene solution. By these procedures the authors were able to separate the solid hydrocarbons of the petrolatum into narrow fractions that are more uniform in composition. The physicochemical properties and structural group composition of the petrolatum and the fractions segregated from the petrolatum aree listed in tables. The physicomechanical properties of solid hydrocarbons are characterized by the residual stress in shear and the breaking point, which are governed by the bulk strength and plastic properties of the solid hydrocarbons. The residual stress in shear was determined by the cone submergence method and the breaking point by a modified Fraas method. Data are presented which show that the components contributing to the strength of petrolatum are n-paraffins and naphthenes with long unbranched paraffinic side chains (hydrocarbons that form adducts with urea), and the main contributors to the plasticity of petrolatum ar the isoparaffins and naphthenes (which do not form adducts). 3 refs.