1,3,5-Trioxane Crystals
1,3,5-Trioxane forms six-membered ring with three oxygen hetero-atoms from formaldehyde cyclization. Used in polymers despite chapter note exclusion reference. HTS 2932.99.90 as defined oxygen heterocycle.
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More Specific Codes
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Alternative Classifications
This product could be classified differently depending on its characteristics or intended use.
If formaldehyde function recognized
Aldehyde polymers/cyclics may classify by oxygen function.
If stabilized solutions
Aqueous or solvent mixtures classify as preparations.
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Import Tips & Compliance
• Acid stabilizer prevents depolymerization during shipping
• Melting point 62°C confirms crystalline form
• Distinguish from paraformaldehyde (Chapter 39)
Related Products under HTS 2932.99.90
Trioxane Pharmaceutical Intermediate
Trioxane is a heterocyclic compound with oxygen hetero-atoms forming a six-membered ring, used as an intermediate in pharmaceutical synthesis. It falls under HTS 2932.99.90 as a heterocyclic compound with oxygen hetero-atoms only, not elsewhere specified in heading 2932. This classification applies to pure chemical forms without additional functional groups that would shift it to other subheadings.
Morpholine Industrial Grade
Morpholine is a six-membered heterocyclic ring with one oxygen and one nitrogen hetero-atom, but classified here due to oxygen hetero-atom specification. Used in rubber curing and corrosion inhibitors. HTS 2932.99.90 as other oxygen-containing heterocycles.
Crown Ether 18-Crown-6
18-Crown-6 is a macrocyclic polyether with six oxygen hetero-atoms in 18-membered ring, used for phase transfer catalysis. HTS 2932.99.90 covers as other oxygen heterocyclic compounds. Excluded from acyclic ethers of heading 2909.
Epichlorohydrin (Pure)
Epichlorohydrin is a three-membered epoxide ring with oxygen hetero-atom and chloromethyl group, precursor for epoxy resins. Despite epoxide note exclusion, classified 2932.99.90 as halogenated oxygen heterocycle. Chapter notes distinguish from simple epoxides.
Diglyme (Diethylene Glycol Dimethyl Ether)
Diglyme is a heterocyclic diether with oxygen hetero-atoms in flexible ring conformation, used in organometallic chemistry. HTS 2932.99.90 as other oxygen heterocycles distinguished from acyclic ethers.
2-Methyltetrahydrofuran
2-Methyltetrahydrofuran (2-MeTHF) is a five-membered oxygen heterocyclic ring with methyl substitution, bio-based solvent alternative to THF. Classified HTS 2932.99.90 as substituted oxygen heterocycle.