| A combined extraction and calorimetric titration method for determining coal liquid compounds is described. Coal liquids are extracted in the presence of a mixed solvent consisting of 60 percent methanol/40 percent H$sb2$O (v/v), to which either HCl or NaOH is added. Compound classes are identified by reaction in the calorimeter from their characteristic heats of proton ionization and equilibrium constants (pK$sb{rm a}$ values). Compounds identified in the mixed solvent extracts have included both acids (phenols and carboxylic acids) and bases (pyridines, anilines, and alkylamines).;Results from extraction work done on a mid-boiling 750$spcirc$F Wilsonville hydrocracker product (T102T8) have shown that only about 30 percent of total basic nitrogen is extracted, while about 80 percent of total phenols and carboxylic acids are extracted. Similar work on ten 50$spcirc$F distillates from a Wilsonville hydrotreater product (T105OH) shows nearly identical results for phenols and carboxylic acids (e.g., 80 percent of acids), while up to 80 percent of the basic nitrogen was extracted. Differences in the fraction of basic nitrogen extracted from the two liquefaction products reflect differences in the basic nitrogen content in low-boiling (below 700$spcirc$F) distillates.;Nitrogen and oxygen compounds not extracted are those in high-boiling (above 700$spcirc$F) distillates that are too hydrophobic to transfer to the mixed solvent phase. This hydrophobicity is attributed to such factors as molecular weight and/or complexation in the organic phase. |
