Search results for "Humic substances O-Alkylation Phase-transfer catalysis Tetrabutylammonium hydroxide NMR FTIR"

O-Alkylation of a lignite humic acid by phase-transfer catalysis

2006

A mild phase-transfer catalytic reaction has been conducted to O-alkylate the acidic functions of a lignite humic acid (HA), using tetrabutylammonium hydroxide as the phase-transfer catalyst. The HA acidic functional groups were made to react, in tetrahydrofuran, by nucleophilic substitution with several alkyl halides-methyl iodide, and ethyl, propyl, and butyl, and benzyl bromide. The occurrence of the O-alkylation reaction was assessed by elemental analysis and 1H NMR, CPMAS 13C NMR, and FTIR spectroscopy. Bonding of alkyl groups increased the carbon and hydrogen content and the H/C ratios of all the humic reaction products. Increased nitrogen in the reaction products suggested incomplete…