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US 3,932,494 AGranted
Thiohumic acid, a process for preparing same, and its use for absorbing heavy metal ions
AssigneeDirector-General of Agency of Industrial Science and Technology
InventorsHisayoshi Yoshida, Takato Nakamura, Masanao Nakagawa, Seiji Arita, Toshiharu Miki
Life of this patent
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Abstract
The compound thiohumic acid resulting from replacing at least a part of the carboxyl groups in humic acid by thiocarboxyl groups, i.e., ##EQU1## as well as a heavy metal adsorbent containing thiohumic acid as its active ingredient. This new compound is obtained by treating humic acid with a halogenating agent to form humic acid halide and treating such halide with a thiolating agent.
Claims2
A thiocarboxyl derivative of humic acid prepared by (1) reacting:
- a. regenerated humic acid prepared by the oxidation of coal with nitric acid,
- b. humic acid prepared by the extraction of lignite with alkali,
- c. regenerated humic acid prepared by the oxidation of coal tar pitch with air, or
- d. granular oxidized coal obtained by the oxidation of granular semi-coke with nitric acid,
- with a halogenating agent of the group consisting of thionyl chloride, thionyl bromide, phosphorus trichloride, phosphorus pentachloride and phosphorus oxychloride at a temperature ranging from room temperature to the boiling point of said halogenating agent;
- and (2) reacting the resultant acid halide with a thiolating agent of the group consisting of hydrogen sulfide or alkali metal hydrosulfide to produce the thiocarboxyl derivative containing about 2-6 meq/g of thiocarboxyl groups.
3 more elements
Dependencies are inferred from the claim text.