Solubilization of Coal by a Treatment with Butylzinc Compounds under Mild Conditions. —Active Species in a Zinc-Butyl Iodide System for Coal Solubilization—

Abstract

Abstract To elucidate the effectiveness of a treatment of coal with butylzinc compounds on coal solubilization, Yubari coal was treated with Bu2Zn and/or BuZnX (X = Cl, Br, I) in the presence or absence of alkyl halide (RX). Both the treatment using Bu2Zn or BuZnI and that with a combination of Bu2Zn and RX (X = Cl, Br) were not very effective for coal solubilization, whereas the combination of Bu2Zn, BuZnX (X = Cl, Br, I) and BuX (X = Cl, Br, I) was very effective. The best yield of a benzene-soluble product (BS) of Yubari coal was 96%. The 13C NMR and FT-IR spectra of each BS fraction of Yubari coal treated with 13CH3I, CH3I, and BuI, respectively, in the presence of BuZnI and Bu2Zn showed that the alkyl and butyl groups from RX and butylzinc compounds were introduced into the BS fractions according to addition and substitution toward aromatic moieties. The addition of alkyl groups to aromatic moieties seemed to be more effective coal solubilization than the substitution of alkyl groups. These results indicate that BuZnI, Bu2Zn, and BuI are indispensable species in the Zn/BuI system for effective coal-solubilization.