The Selecting Collection Of Solvent Extracts Of Coal

With the intention of collecting the aromatic compound selectively in the coal liquefaction products, four Chinese coal samples(DT,SF,TFDX,YM) were extracted by acetonitrile, tetrahydrofuran (THF) and pyridine sequentially in terms of solvent polarity. THF extracts was separated by Gel Permeation Chromatography (GPC) and separated compounds was detected by Photodiode Array Detector (PDA) under 200 to 400nm wavelength. The results shown that the THF extracts are mainly consists of with different kinds of substituted functional aromatic compounds, the maximum molecular weight (MW) lower than the 840amu. Furthermore, aromatic monomer as target compounds were enriched by Solid Phase Extraction (SPE) method, in which C18 SPE-PAK~R was used as the sorbent. By changing the solvent intensity of eluent, a series of mixture (THF/H2O 20, 50, 100 vol%) were used to flush the compatible compounds and the objective compounds adsorbed onC18 were flushed by chlorine methane eventually. The fractions were analyzed by liquid chromatography-mass spectrum (LC-MS) after dry N2 concentration and analyzing results shown that the main fractions adsorbed on C18 were lower polarity aromatic compound, also some compounds with conjugate bond were detected.For the purpose of getting the exclusive enrichment method of particular components, such as separation aromatic species from coal extracts, pyridine extracts of samples DT and HDG were selected in this experiment. Solid phase extraction (SPE) method was chosen to collect the object compounds by using the sample of THF and acetic acid soluble composition from Pyridine extracts, and different ratio of THF/H2O solution used as eluent, chlorine methane as wash solvent. The fractions were analyzed by Gas Chromatography-Mass Spectrum (GC-MS), the results told us that the fractions were mainly consists of Butylated Hydroxytoluene and small ketone and alicyclic compounds. Nevertheless, we could not find the same compositions in SF and TFDX pyridine extracts, which suggested that separation and enrichment was not only related with operation conditions but also related with the selected coal samples and extraction solvent.