Pretreatment of solid, naturally-occurring carbonaceous material

Abstract

Solid, naturally-occurring carbonaceous materials such as coal, lignite, peat and the like are treated by oxygen-alkylation or oxygen-acylation employing a phase transfer reaction under mild conditions. The treated coal may then be liquefied, gasified, pyrolyzed, solubilized or otherwise further processed to obtain useful products therefrom. For example, liquid products derived from coal so treated are more compatible with petroleum products and evidence lower viscosity and boiling range than liquid products not so treated. The solubility of coal bottoms is increased in common organic solvents as compared with coal bottoms derived from untreated coal. The phase transfer reaction chemically alters phenolic and carboxylic functional substituents. These two very polar functional groups are converted to relatively non-polar ethers and esters, respectively. The O-alkylation or O-acylation is carried out in a binary liquid phase solution (organic and water phases with a solid phase suspended in the medium). A quaternary ammonium or phosphonium salt is reacted with alkali metal or alkaline earth metal base to produce the corresponding quaternary ammonium or phosphonium base. This quaternary base is non-nucleophilic and readily removes the phenolic and carboxylic protons but does little else to the coal structures. After the removal of weakly acidic protons by the base, the phenoxides and carboxylates which are produced then undergo O-alkylation or O-acylation.