2-Mercaptopropionic Acid
2-Mercaptopropionic acid (HS-CH2-CH2-COOH) is an organo-sulfur carboxylic acid with both mercapto and carboxyl groups on adjacent carbons. Classified under HTS 2930.90.4920 as 'other mercaptocarboxylic acids' per Chapter 29 notes defining organo-sulfur compounds. Used in pharmaceutical intermediates and chelating agents.
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Alternative Classifications
This product could be classified differently depending on its characteristics or intended use.
If -SH groups form thioether linkages rather than free mercapto
Thioethers classified in 2930.20; Chapter 29 prioritizes latest numerical heading for sulfur functions.
If for industrial bulk polycarboxylic acids without sulfur
Non-sulfur acyclic polycarboxylic acids fall to 2917; mercapto defines 2930 organo-sulfur nature.
If imported as organic salt rather than free acid
Per Chapter 29 note 3(C)(1), salts classified with parent organic acid in 2930.90.
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Import Tips & Compliance
• Submit NMR or GC-MS spectra confirming mercapto position and >95% purity for Chapter 29 classification
• Include SDS with GHS corrosive pictograms; UN 2922 for solid form handling
• Distinguish from thioethers (2930.20) by confirming free -SH via titration analysis
Related Products under HTS 2930.90.49.20
Thioglycolic Acid
Thioglycolic acid (mercaptoacetic acid), HSCH2COOH, is a chemically defined organic compound containing a mercapto (-SH) group directly linked to a carbon atom and a carboxylic acid function. It falls under HTS 2930.90.4920 as a mercaptocarboxylic acid within the organo-sulfur compounds of Chapter 29. Commonly used in hair perming solutions, metal extraction, and polymer synthesis.
3-Mercaptopropanoic Acid
3-Mercaptopropanoic acid features a three-carbon chain with terminal mercapto and carboxylic acid groups. This separate chemically defined compound qualifies under HTS 2930.90.4920 as a mercaptocarboxylic acid per Chapter 29 scope. Applied in polymer cross-linking and biochemical research.
Mercaptosuccinic Acid
Mercaptosuccinic acid (thiomalic acid) contains both mercapto and dicarboxylic acid functions in a single molecule. Falls under HTS 2930.90.4920 as 'other mercaptocarboxylic acids' since organo-sulfur takes precedence over oxygen functions per Chapter 29 classification rules. Used in heavy metal detoxification.
2-Mercaptobenzoic Acid
2-Mercaptobenzoic acid (thiosalicylic acid) combines aromatic carboxylic acid with ortho-mercapto group. Classified in HTS 2930.90.4920 as aromatic mercaptocarboxylic acid under organo-sulfur compounds. Key intermediate for thioindigo dyes and pharmaceuticals.
4-Mercaptobenzoic Acid
4-Mercaptobenzoic acid features para-substituted mercapto and carboxylic groups on benzene ring. HTS 2930.90.4920 classification as aromatic mercaptocarboxylic acid per Chapter 29 organo-sulfur provisions. Utilized in nanotechnology and self-assembled monolayers.
Captopril
Captopril, (2S)-1-[(2S)-3-mercapto-2-methylpropionyl]-L-proline, contains a mercaptocarboxylic acid side chain. Despite complex structure, classified under HTS 2930.90.4920 as its mercapto acid functionality defines the organo-sulfur nature per Chapter 29. Pharmaceutical API for hypertension treatment.