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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 Mw. 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