Other
Heterocyclic compounds with oxygen hetero-atom(s) only: > Other: > Other: > Other > Other
Duty Rate (from China)
Articles the product of any country, as provided for in subdivision (aa)(ii) of U.S. note 2 to this subchapter
Products classified under HTS 2932.99.90.90
Trioxane Pharmaceutical Intermediate
Trioxane is a heterocyclic compound with oxygen hetero-atoms only, used as an intermediate in pharmaceutical synthesis for antimalarial drugs like artemisinin derivatives. It features a six-membered ring with three oxygen atoms, fitting precisely under HTS 2932.99 for other heterocyclic oxygen compounds not elsewhere specified. This pure chemical compound meets Chapter 29 requirements for separate chemically defined organic compounds.
Morpholine Technical Grade
Morpholine features a six-membered heterocyclic ring containing two oxygen and two nitrogen hetero-atoms, used in rubber vulcanization and pharmaceutical synthesis. Despite nitrogen presence, classified by last numerical heading rule at 2932.99.90.90 when oxygen hetero-atom structure predominates. Meets Chapter 29 definition for heterocyclic compounds.
Tetrahydrofuran Stabilized
Tetrahydrofuran (THF) is a five-membered heterocyclic ring with one oxygen hetero-atom, essential solvent for Grignard reactions and polymer processing. Stabilized grade contains BHT to prevent peroxide formation during transport, qualifying under Chapter 29 note 2(f). Classified at 2932.99.90.90 as other oxygen heterocyclic compounds.
2-Methyltetrahydrofuran Bio-Based
2-Methyltetrahydrofuran (2-MeTHF) is a five-membered oxygen heterocyclic derived from renewable furfural, used as green solvent replacing THF in pharma manufacturing. Bio-based variants maintain identical chemical structure qualifying under 2932.99.90.90. Chemically defined heterocyclic compound per Chapter 29 definitions.
Dioxolane Monomer
1,3-Dioxolane features a five-membered ring with two oxygen hetero-atoms, used as comonomer in polyacetal resin production and pharma intermediates. Pure monomer form qualifies as heterocyclic oxygen compound under HTS 2932.99.90.90. Excluded from cyclic ester provisions by Chapter note 5.
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 and metal ion complexation. Pure compound qualifies under 2932.99.90.90 as heterocyclic oxygen compound not specifically excluded. Chemically defined per Chapter 29 note 1(a).
Epichlorohydrin Hydrolyzed Residue
Hydrolyzed epichlorohydrin residue contains glycidol and diol byproducts, classified as oxygen heterocyclic mixture under 2932.99.90.90 when chemically defined isomers predominate. Used in epoxy resin purification processes. Fits Chapter 29 note 1(b) for isomer mixtures.
Furanose Sugar Derivative
Methyl furanoside derivatives feature five-membered oxygen heterocyclic rings from sugar cyclization, used as glycosyl donors in carbohydrate synthesis. Excluded from sugar headings by Chapter 29 priority, classified 2932.99.90.90. Qualifies as chemically defined heterocyclic oxygen compound.
Paraldehyde Stabilized USP
Paraldehyde is trimeric acetaldehyde forming six-membered oxygen heterocyclic ring, used as hypnotic pharmaceutical under USP standards. Stabilized with sulfuric acid traces per Chapter note 2(f), classified 2932.99.90.90. Excluded from aldehyde heading 2912 by cyclic polymer note 5.
1,4-Dioxane ACS Reagent Grade
1,4-Dioxane is a six-membered heterocyclic ring with two oxygen hetero-atoms, widely used as a solvent in chemical analysis and pharmaceutical processing. This ACS reagent grade meets purity standards for laboratory use under HTS 2932.99.90.90 as other heterocyclic oxygen compounds. It qualifies as a separate chemically defined compound per Chapter 29 scope.