2,4-D ester 2,4-D esters 2,4-Dichlorophenoxyacetic acid polypropoxybutyl ester 53467-11-1 Caswell No. 315AY EPA Pesticide Chemical Code 030069 Poly(oxy(methyl-1,2-ethanediyl)), alpha-((2,4-dichlorophenoxy)acetyl)-omega-butoxy-