Section 06 Products of the chemical or allied 29 Organic chemicals 29 01 Acyclic hydrocarbons 29 01 23 - - Butene (butylenes) and isomers thereof 29 01 23 00 - - Butene (butylenes) and isomers thereof Commodity Code Description 29 01 23 00 000 - - Butene (butylenes) and isomers thereof