Alkaline degradation of peat humic acids. Part I. Identification of lipophilic products

Abstract

Alkaline degradation of peat humic acids at 185 °C gives rise to a large number of lipophilic, chloroform-soluble compounds, which have been analyzed by capillary gas-liquid chromatography - mass spectrometry. Identified compounds included 50 aromatic compounds, 20 aliphatic mono- and di-carboxylic acids, 6 alkyl-substituted 2-cyclopentenones and 5 alkyl-substituted 2-hydroxy-2-cyclopentenones. Degradation in the presence of sodium sulfide (Na2S) produces some thiophenes and increases the number of phenolic compounds. The total yields of identified lipophilic compounds were 3.2 % in both the presence and absence of Na2S. The formation of thiophenes and alkylcyclopentenones suggests the presence of aliphatic 1,4-diketonic structures in peat humic acids.