We earlier documented that our WWII British Allies were, during the war, like our German and Japanese foes at the time, converting coal into some of the liquid fuels needed by their military.
British Scientists are continuing to refine and develop their coal-to-liquid processes, just like researchers in the United States. And, they are using, in their work, a coal found in the US which seems to have become a standard for CTL experimentation: "Illinois No. 6". It is a specification we have seen in several other research citations, from other places.
The technically dense Excerpt, with comment following :
"Title: Reductive alkylation of Illinois No. 6 coal in liquid ammonia
Author: Handy, C.I., Stock, L.M.
Date: August 01, 1982
Journal: Fuel; (United Kingdom); Journal Volume: 61:8
Abstract: The reductive alkylation of Illinois No. 6 coal was investigated using alkali metals and alkyl halides in liquid ammonia. Potassium is the most effective reducing agent and butyl iodide is the most effective alkylating agent for the preparation of coal alkylate that is soluble in tetrahydrofuran. The overall yield of soluble product is often improved through the reaction of the tetrahydrofuran-insoluble portion of the initial reaction products with an alkylating agent in the presence of tetrabutylammonium hydroxide. The infrared spectra of these materials suggest that the phase transfer agent catalyses the esterification of residual carboxylic acid functions. The intermolecular interactions between such acid groups and acceptor groups markedly restrict the solubility of the coal alkylate. The gel permeation chromatograms of the soluble reaction products are essentially featureless with only modest maxima at short and long elution volumes. The proton and carbon nuclear magnetic resonance spectra of the reductive methylation products, prepared using methyl-/sup 13/C iodide, suggest that carbon alkylation exceeds oxygen alkylation and that the alkylation of phenolic groups is the dominant O-alkylation reaction. The spectra also suggest that fewer ethers are cleaved in the reaction in liquid ammonia than under the conditions of Sternberg reaction. (32 refs.)"
Note: We are not technically competent to explain the process of "alkylation". However, other, easily-accessible web-based references, explain that coal can be "alkylated" with well-understood comparative ease, and that such alkylated coal compounds, once produced, dissolve readily in a selection of common organic solvents, which makes subsequent refining into useful liquid fuels and chemicals a relatively straightforward process.