RECOVERY OF WAX FROM NEYVELI LIGNITE TAR AND ITS STRUCTURAL CHARACTERIZATION

An efficient method is described for the recovery of wax from lignite tar by solvent extraction followed by isolation of the wax from the ex tract. Light petroleum (boiling range 60-80-degrees-C) was used as the solvent. Under optimum conditions (i.e. solvent:feed ratio = 4 and ti me of reflux 1 h at 70-degrees-C), up to 85% of the tar could be extra cted. In the next stage, almost the entire amount of wax present in th e extract was precipitated by first distilling off the solvent and the n treating the residual tar oil with acetone at 10-degrees-C. The yiel d of wax was found to be 14.6% on a dry tar basis. The recrystallized wax was characterized by elemental analysis, Fourier transform i.r. an d H-1 n.m.r. spectroscopy and molecular weight determination. The stud ies revealed that the wax obtained from Indian lignite tar primarily c onsists of long-chain (approximately C30) paraffins together with smal l amounts of long-chain fatty acids and their esters, in addition to u nsaturates of the type RCH = CH2; RCH = CHR1 and RR1C = CH2.