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ABSTRACT:
Polyols from vegetable oils can replace petroleumbased polyols in the preparation of polyurethanes and polyesters in a wide range of applications. However, previous preparation methods are either too costly, inefficient, or yield secondary alcohols, which are less reactive than the desired primary alcohols. The objectives of this study were to prepare primary soy-based polyols by a new catalytic ozonolysis process and to characterize the composition of the product mixture. In this new process, the polyols were prepared by passing ozone through a solution of soybean oil and ethylene glycol in the presence of an alkaline catalyst. Unlike conventional ozonolysis that yields aldehydes and carboxylic acids by spontaneous decomposition of the ozonide intermediates, the ozonides in our method reacted with the hydroxyl group of the glycol to form an ester linkage with a terminal hydroxy group. Statistical analysis of the product mixture indicates that the resulting polyol mixture is more uniform than the original TG mixture, having (2-hydroxy)nonanoate as the major component of the new hydroxyl functional TG. The chemical structure of the polyols produced was further characterized by iodine number and 13C NMR and FTIR spectroscopy, which confirmed the cleavage of the double bonds, the presence of hydroxyl groups, and the formation of new ester linkages.
Paper no. J10972 in JAOCS 82, 653-659 (September 2005).
KEY WORDS: Ozone, polyol, soybean oil.
Soybean oil is an abundant renewable resource that can be used to manufacture of polyesters and polyurethanes provided it can be suitably modified to have alcohol groups in its structure. In addition to being a renewable resource, there are several other compelling reasons to use soy-based polyols as starting materials: The production of polyols from petrochemicals requires a great deal of energy, as oil must be drilled, extracted from the ground, transported to refineries, refined and otherwise processed to yield suitable polyols. Furthermore, the process itself is costly and adversely affects the environment. Thus, it is desirable to replace petroleum-based polyols with the more versatile, renewable, less costly, and more environmentally friendly biobased polyols. Several researchers have investigated incorporating alcohol groups into soybean oil and other FA TG derived from vegetables oils.
One of the early methods of preparing polyols from various vegetable oils was based on transesterification of the FA...