Synthesis and in situ transformation of poly(oxybutylene)amides by butoxylation

A family of gasoline detergents was prepared by a two-step process—(1) preparation of amide initiators by reacting hydrophilic amines with ethyl acetate at high temperature; (2) consecutive butoxylation of the initiators with 1,2-epoxybutane (BO) to obtain oil-soluble products. The process led to the preparation of amide-initiated butoxylates, which were characterized by FTIR, NMR, and amine titration. During the butoxylation, it was found that the unexpected ester by-products were generated via an amide/ester exchange. The reaction profile was studied. The amide/ester exchange reaction, characterized by IR absorption of amide (1650 cm^?1) vs. ester (1735 cm^?1), reached equilibrium during the process of butoxylation to 1600 M_w. Steric hindrance of the amide structures is an important factor controlling the formation of these ester byproducts. Selective hydrolysis to remove the ester by-products is necessary to render the final product with an improved engine performance of octane requirement. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 435–445, 2001