Acrylonitrile and other nitrile-function compounds fall under heading 2926 because the defining functional group is the nitrile (–C≡N). Isocyanates, which carry the –N=C=O group, are classified under the nitrogen-function compounds heading for isocyanates instead. The distinction is chemical: the functional group present on the molecule determines the correct heading.

Yes. Alpha-phenylacetoacetonitrile (APAAN), covered under subheading 292640, is an internationally recognized drug precursor subject to DEA import controls and reporting requirements. Importers should verify DEA registration and permit requirements before shipment.