Coal. Kinetics of O-Alkylation

Article abstract of DOI:10.1021/ja00397a025

The kinetic reactivities of the acidic hydroxyl groups in coal were measured.The chemical action of quaternary ammonium hydroxyde bases in the presence of alkylating agents was used as the probe.Both Illinois No. 6 bituminous and Rawhide subbituminous coals contain aromatic and aliphatic hydroxyls as well as lesser amounts of carboxylic acids.Illinois coal was found to O-alkylate at a faster rate than Rawhide coal.The reactivities of the acidic functional groups in the coals were correlated to the reactivity of acidic groups in model compounds.This was accomplished by both relative and absolute kinetic rate measurements on each coal and a series of model systems.It was discovered that the activation energy associated with the nucleophilic displacement determined the rate of O-alkylation of the coal.Therefore, the rate of the reaction is not limited by mass transport of the chemical reagents into the coal structure.In this sense, O-alkylation of coal is a most unique reaction.