Role of the hydrogen-donor solvent in coal hydroliquefaction. Progress report, September 1, 1979-November 30, 1980

Abstract

The principal disproportionation products of 1,2-dihydronaphthalene (1,2-DHN) are naphthalene (Nap) and tetralin (Tet). Dimers of 1,2-DHN constitute 17% and 5% of the respective liquid phase (285 to 315/sup 0/C) and gas phase (385 to 410/sup 0/C) products. The Nap:Tet ratio is one in the presence of solvents, but is > 1 and < 2 in their absence. Gas phase reaction kinetics indicate that 1,2-DHN disappears by simultaneous first and second order reactions. These results are consistent with a concerted second order disappearance of 1,2-DHN to produce equal amounts of Nap and Tet, accompanied by either carbonium ion or free radical side reactions that produce more Nap than Tet, together with 1,2-DHN dimers. Preliminary evaluation of the liquid phase kinetics suggest they follow a similar pattern. The structures of the dimers should reveal whether they were formed by a carbonium ion or free radical mechanism. Isolation of the dimers will be attempted by preparative GC (PGC) followed by TLC to remove thermal decomposition products formed during PGC. Exploratory results suggest that heating 1,2-DHN (300/sup 0/C) in the presence of tetraphenylethane, which dissociates into diphenylmethyl radicals, may constitute a model for the free radical conversion of 1,2-DHN into Nap during coal hydroliquefaction. more » Further studies of this system will be conducted. « less