Laurent's Acid (2-Naphthylamine-3,6-disulfonic Acid)
Laurent's acid, a di-sulfonic derivative of 2-naphthylamine, functions as a dye coupler in textile coloration chemistry. Covered by HTS 2922.21.4000 as specified in additional U.S. note 3 for import quotas. Despite two sulfonic groups, it remains classified here due to primary amino-hydroxy-naphthalene structure.
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Alternative Classifications
This product could be classified differently depending on its characteristics or intended use.
If specifically amino-8-naphthol-3,6-disulfonic acid (H-acid) isomer
Statistical suffixes distinguish specific isomers within the same heading.
If sulfur atom directly linked to carbon beyond sulfonic function
Chapter note defines organo-sulfur exclusion for sulfonated oxygen-function compounds.
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Import Tips & Compliance
• Secure end-user certificates demonstrating dye production use to qualify for quota allocations
• Document sulfonic acid content via titration analysis for potential statistical reporting suffixes
• Separate from other naphthylamine sulfonic acids in manifests to prevent quota exhaustion
Related Products under HTS 2922.21.40.00
Schaeffer's Salt (2-Naphthylamine-6-sulfonic Acid)
Schaeffer's salt is a sodium salt of 2-naphthylamine-6-sulfonic acid, a key aminohydroxynaphthalenesulfonic acid derivative used primarily as an intermediate in azo dye synthesis. It falls under HTS 2922.21.4000 as a product described in additional U.S. note 3 to section VI, which covers specific organic compounds subject to quota restrictions for dye production. The compound features both amino and sulfonic acid oxygen functions on a naphthalene ring.
Tobias Acid (2-Naphthylamine-8-sulfonic Acid)
Tobias acid is the sodium salt of 2-naphthylamine-8-sulfonic acid, widely used as a diazo component in manufacturing acid dyes and pigments. Classified under HTS 2922.21.4000 due to its status in additional U.S. note 3 to section VI, restricting imports for dye production. It qualifies as an oxygen-function amino-compound with amino, hydroxy, and sulfonic groups.
Bayer's Acid Salt (1-Naphthylamine-4-sulfonic Acid Sodium Salt)
Bayer's acid sodium salt serves as a crucial intermediate for direct and reactive dyes, featuring the aminohydroxynaphthalenesulfonic acid structure. It is specifically listed under HTS 2922.21.4000 per additional U.S. note 3 to section VI for quota-controlled dye chemicals. The compound's classification follows chapter rules prioritizing oxygen-function amino-phenols.
Neville-Winter Acid (1-Naphthylamine-5-sulfonic Acid)
Neville-Winter acid is an aminohydroxynaphthalenesulfonic acid used in acid dye manufacturing, subject to HTS 2922.21.4000 quotas under U.S. note 3 to section VI. Its structure with amino group ortho/para to sulfonic acid enables diazotization for azo coupling. Classification adheres to chapter priority for oxygen-function amino-naphthols.
K-acid (4-Amino-5-hydroxynaphthalene-2,7-disulfonic Acid)
K-acid serves as an important coupling component for substantive dyes due to its multiple sulfonic groups enhancing water solubility. HTS 2922.21.4000 applies per U.S. note 3 listing for quota purposes. The compound exemplifies oxygen-function amino-naphthols with salt-forming capability.