再生フミン酸の構造と特性に関する研究 (III)

再生フミン酸と炭酸エチレンの反応

抄録

The reaction of ethylene carbonate with the regenerated humic acid prepared from Takamatsu coal (C: 75.7%) by oxidation with nitric acid has been investigated.
Hydroxyethylation of humic acid with ethylene carbonate easily occured and carboxyl group and phenolic hydroxy group in humic acid were converted into ester and ether, respectively.
In the case of alkali (Na₂CO₃) catalyst, the formation of polyether followed after hydroxyethylation of humic acid. In the case of acid (H₂SO₄) catalyst, the crosslinkage formation through ethylene group occured after hydroxyethylation of humic acid.
Humic acid became insoluble in an aqueous alkali solution by reaction with ethylene carbonate. In the case of acid catalyst, it was possible to obtain the product which was insoluble in an aqueous alkali solution but retained the most part of acidic group of the original regenerated humic acid.
The reaction products showed a strong absorption band at 1, 250cm^-1 (C-O-C stretching vibration of ester) in IR spectrum so that the carboxyl group in the regenerated humic acid is considered to be the aromatic carboxyl group.