Subheading 2905 39 of the Combined Nomenclature covers remaining aliphatic diols (dihydric alcohols) not classified in subheadings 2905 31 (ethylene glycol) or 2905 32 (propylene glycol). The most commercially significant substances within this subheading include neopentyl glycol (2,2-dimethyl-1,3-propanediol, CAS 126-30-7), 1,4-butanediol (BDO, CAS 110-63-4) and diethylene glycol (DEG, CAS 111-46-6). Neopentyl glycol is a key monomer for alkyd resins, UV-stable polyesters and engineering plastics. 1,4-butanediol is used as a monomer for polyurethanes (PU), polybutylene terephthalate (PBT) and as a precursor to gamma-butyrolactone (GBL). Diethylene glycol serves as a raw material for polyester resins, lubricants and plasticisers. In accordance with Note 1 to Chapter 29 of the CN, classification under subheading 2905 39 requires the substance to be a separately chemically defined organic compound. Mixtures of glycols are classified outside Chapter 29. Classification follows the General Rules for the Interpretation (GRI) of the CN, with Rules 1 and 6 being particularly relevant for subheadings. In case of doubt, a Binding Tariff Information (BTI) ruling from the competent customs authority is strongly recommended.

The import of diols falling under subheading 2905 39 into the European Union is subject to REACH Regulation (EC) No 1907/2006. Importers placing neopentyl glycol, 1,4-butanediol or diethylene glycol on the EU market at 1 tonne or more per year must hold a valid REACH registration with ECHA or appoint an Only Representative (OR) established in the EU. Particular attention must be paid to 1,4-butanediol, which is a metabolic precursor of GBL and GHB (controlled narcotic substances). Its import and trade may therefore be subject to additional requirements arising from Regulation (EC) No 273/2004 and Regulation (EC) No 111/2005 on drug precursor controls. Diethylene glycol intended for food or pharmaceutical use is subject to the relevant sector-specific regulations. CLP Regulation (EC) No 1272/2008 requires importers to correctly classify, label and package substances before placing them on the EU market. A Safety Data Sheet (SDS) compliant with Regulation (EU) 2020/878 (16 sections) is a mandatory document when importing and supplying substances in the supply chain and must be prepared in the official language of the country of delivery. Substances from this subheading should be checked against the ECHA SVHC candidate list and any restrictions under Annex XVII to REACH.

MFN (Most Favoured Nation) duty rates for goods under subheading 2905 39 must be verified in the European Commission's TARIC database, as they are subject to annual tariff reviews. Autonomous tariff suspensions (Council Regulations on tariff suspensions) may apply to certain diols within this subheading if the substance is not available in sufficient quantity or quality on the Union market — importers may apply to the European Commission for a suspension. Preferential duty rates are available under EU Free Trade Agreements, including CETA (Canada), the EU-Japan EPA, the EU-South Korea FTA, the EU-UK TCA, and the Generalised Scheme of Preferences (GSP) for developing countries. Obtaining a preferential rate requires compliance with rules of origin and presentation of a valid proof of origin: EUR.1 certificate, invoice declaration or REX statement. The importer should verify in TARIC whether anti-dumping or countervailing measures apply to the specific product and country of origin. Subheading 2905 39 falls within Section VI (Products of the chemical industry), Chapter 29 — organic chemicals. The legal basis for import is the Union Customs Code (Regulation (EU) No 952/2013). All duty rates and trade measures must be verified in the TARIC database.

Organic substances under CN code 2905 39 (other diols) require detailed chemical documentation for customs clearance. The Safety Data Sheet must comply with REACH Annex II. Substances classified as hazardous under CLP require GHS pictogram labelling. Transport follows ADR (road) or IMDG (maritime) regulations. Some organic substances may be subject to export controls as dual-use goods. Importers should verify whether the substance requires REACH authorisation (Annex XIV) or is subject to restrictions (Annex XVII). A Certificate of Analysis confirming purity and composition is recommended.