부산대학교 도서관

PETROLEUM WAXES are the solid hydrocarbon residues remaining at the end of the refining process either in the lube stream (as mainly paraffin and intermediate waxes) or in the residual lube stock “tank bottoms” (as higher melting microcrystalline waxes). The waxy oil is fractionated to produce an oily wax, called slackwax. This is separated by solvent extraction and fractionated into different melting point ranges to give waxes with a variety of physical characteristics. Paraffin waxes consist mainly of straight chain alkanes (also called normal alkanes), with small amounts (3 to15%) of branched chain alkanes (or iso-alkanes), cycloalkanes, and aromatics. Microcrystalline waxes contain high levels of branched chain alkanes (up to 50%) and cycloalkanes, particularly in the upper end of the molecular weight distribution. Paraffin waxes contain alkanes up to approximately 600 molecular weight, whereas microcrystalline waxes can contain alkanes up to 1100 molecular weight.