N,N-Dimethylformamide (DMF, CAS 68-12-2) is imported under the U.S. Harmonized Tariff Schedule statistical reporting number 2924.19.11.20; the Column 1 General rate of duty is 6.5 percent ad valorem. For goods of China, the Section 301 stack adds 25 percent ad valorem through Chapter 99 subheading 9903.88.03, yielding a combined tariff rate of 31.5 percent ad valorem before merchandise processing and harbor maintenance charges. This technical note covers the tariff-line scope, entry calculation, valuation rules, and classification boundaries for DMF when imported as bulk solvent, tolled reaction mass, or formulated mixture.

The ten-digit line 2924.19.11.20 is a chemically defined single compound, not a generic solvent basket. Under General Rule of Interpretation 1 and 6, classification rests on the acyclic carboxyamide function rather than end use. DMF has the molecular formula C3H7NO, a molecular weight of 73.10 g/mol, a flash point of 58 °C closed cup, a dielectric constant of 36.7 at 25 °C, an autoignition temperature of 445 °C, and a lower explosive limit of 2.2 percent by volume with an upper explosive limit of 15.2 percent by volume. Commercial bulk specification commonly requires a purity of at least 99.9 percent by weight, water content not more than 0.05 percent by weight as determined by ASTM E203, acidity as formic acid not more than 0.005 percent by weight, and an APHA color of not more than 10 Pt-Co by ASTM D1209. Shipments containing stabilizers or additives may remain in the same ten-digit line only if the additives are permitted by Chapter 29 note 1 and do not change the essential character of the chemically defined substance.

What Is the Exact Duty Stack for a China-Origin Bulk Entry?

For China-origin DMF, the entry summary reports both 2924.19.11.20 and 9903.88.03. The base 6.5 percent duty is assessed on transaction value under 19 CFR 152.101. The Section 301 additional duty is also assessed on entered value, so the arithmetic is additive. The Section 301 action for List 3 merchandise began at 10 percent under 83 FR 47974 and was raised to 25 percent under 84 FR 20459. The current stack therefore consists of 6.5 percent base duty, 25 percent Section 301 duty, and 31.5 percent combined tariff, excluding fees.

For an entered value of 120,000 USD, the base duty is 7,800 USD, the Section 301 duty is 30,000 USD, and the combined tariff is 37,800 USD. The merchandise processing fee under 19 CFR 24.23 at 0.3464 percent is 415.68 USD; the harbor maintenance fee under 19 CFR 24.24 at 0.125 percent is 150.00 USD. Total government charges equal 38,365.68 USD for that representative entry, before brokerage, port security, inspection, and demurrage. Because the MPF has a per-entry minimum of 29.66 USD and maximum of 575.35 USD, small express shipments and very large bulk entries do not follow a simple linear fee calculation across all shipment sizes.

When DMF is sourced from a country other than China and entered under Column 1 General, the Section 301 stack does not apply. The Column 2 duty rate for this statistical line is 30.5 percent ad valorem for countries listed under General Note 3(b). Importers claiming a non-China origin must maintain documentation under 19 CFR 134.1, including certificates of origin, batch production records, supplier affidavits, bills of lading, and transport routing. DMF produced by the reaction of dimethylamine with carbon monoxide or with methyl formate is usually considered to originate where that chemical transformation occurs, but repacking, blending, and filtration are not substantial transformations. Under 19 CFR 152.101 through 152.103, the reported customs value cannot be reduced by foreign inland freight, assists, royalty payments, or other items that are part of the transaction value.

When Blending, Tolling, or FTZ Admission Changes the Classification Analysis

A formulated solvent containing DMF may not fall under 2924.19.11.20. Under GRI 1 and GRI 3(b), the classification of a mixture is determined by the heading that applies by name to the mixture or, absent that, by the component imparting essential character. A DMF/water or DMF/toluene reaction mixture may be classified elsewhere, and the Section 301 Chapter 99 code follows the underlying tariff item. No single numerical threshold is dispositive under the HTSUS, but the essential-character determination must be documented with the mixture formula and downstream function. Tolling operations in a foreign-trade zone do not avoid the duty stack. Under 19 CFR 146.41, privileged foreign merchandise retains its foreign status and is subject to the duties applicable at the time of entry for consumption. If DMF is blended in an FTZ and entered as a different statistical line, the duty stack is recomputed on the entered merchandise, not on the original DMF volume.

The tariff stack changes solvent acquisition economics in polyacrylonitrile wet spinning and polyurethane resin processing. DMF has a donor number of 26.6 kcal/mol and dissolves PAN at dope concentrations typically reported between 20 percent and 26 percent by weight. In pharmaceutical syntheses, DMF is an ICH Q3C(R8) Class 2 solvent with a permitted daily exposure of 8.8 mg/day and a concentration limit of 880 ppm in the drug product. These constraints make lower-purity substitution or incomplete distillation operationally restrictive. A 31.5 percent tariff on China-origin DMF therefore cannot be offset by relaxing residual-solvent or water specifications without creating downstream purification costs. For transport, DMF is UN 2265, Class 3, Packing Group III, with a flash point of 58 °C closed cup, placing it at the upper boundary of the USDOT flammable liquid definition.

Entry Summary Rejection Causes Under 19 CFR 141.61

Automated Commercial Environment validation rejects entry summaries when the Chapter 99 code is missing or inconsistent with the reported country of origin for a covered tariff item. Because 2924.19.11.20 is enumerated in Section 301 List 3, a China-origin entry must transmit 9903.88.03 unless an exclusion applies. A missing Chapter 99 code may trigger a CBP Form 28 Request for Information under 19 CFR 141.61 or a Notice of Action under 19 U.S.C. 1592 if the omission is material. Importers must also ensure that a continuous bond under 19 CFR 113.62 is adequate for the total stack, not only the base duty. The Section 301 exclusion process for List 3 goods has included Chapter 99 exclusion numbers such as 9903.88.33; a claim under an expired or inapplicable exclusion can result in liquidation with interest and penalties under 19 U.S.C. 1505 and 19 U.S.C. 1592.

Duty drawback remains available for DMF imported under 2924.19.11.20 and exported or destroyed under 19 CFR 191. The Section 301 additional duty is a customs duty, not a penalty, and may be recovered through direct identification drawback if export tracing is maintained. For manufacturing drawback under 19 U.S.C. 1313(a) and unused-merchandise drawback under 19 U.S.C. 1313(j), the underlying eight-digit HTS classification governs substitution tests. The Chapter 99 reporting line does not change the underlying tariff classification for drawback purposes. On the regulatory side, DMF is listed in Annex VI to Regulation (EC) No 1272/2008 as Repr. 1B with acute toxicity and eye irritation classifications, and it is subject to the U.S. OSHA permissible exposure limit of 10 ppm as an 8-hour time-weighted average with a skin notation under 29 CFR 1910.1000 Table Z-1. These classifications do not alter tariff treatment, but they require SDS documentation and emergency response information during transport.

When a U.S. importer receives DMF from a non-China supplier but the material was manufactured in China and repacked or diluted without a substantial transformation, CBP may still determine that the good remains a product of China. Repacking, simple filtration, and blending do not confer origin; the operational boundary is the last substantial chemical transformation. Each tolling arrangement requires batch-level production records, purchase orders, process flow diagrams, and transport documentation to survive a CBP origin verification. Published data for this specific configuration is limited; importers should maintain current USTR exclusion lists and use the USHTS online database for Chapter 99 updates before filing each entry.