Separation of Pyridine Extracts of Zonguldak Bituminous Coal by Surface-Modified Silica Gel Liquid Chromatography Columns

Polyethylene glycol (PEG) 20M-modified silica gel stationary phases were investi gated in the separation of pyridine extract of Zonguldak bituminous coal. Silica gel surfaces were made less acidic by the basic PEG 20M. The number of theoretical plates decreased substantially in surface-modified silica gel columns for all model compounds. Resolution decreased as the percentage of PEG charged on silica gel was increased for any combination of the two model compounds. Pyridine extract was separated into n-heptane, toluene, and methanol eluates using the prepared columns. As the percentage of PEG 20M on the silica gel stationary phase was increased, yields of n-heptane eluates were increased, toluene eluates stayed almost unchanged, and methanol eluates decreased. Decrease in the methanol eluates was in favor of the n-heptane eluates. The fractions produced by this method contain constituents that can be reformed to obtain environmentally acceptable liquid fuels.