Ozonolysis of Canola Oil: A Study of Product Yields and Ozonolysis Kinetics in Different Solvent Systems

The use of ozonolysis has been proposed as a step in the production of vegetable-oil-based polyols as replacements for the equivalent petrochemicals. As part of an evaluation of the commercial viability of ozonolysis, the intermediates and products formed from the ozonolysis of canola oil using different protic and aprotic solvents and solvent mixtures were systematically studied by GC-FID and size-exclusion chromatography with refractive index detection (SEC-RI). It was found that the use of an aprotic solvent (ethyl acetate) leads to the formation of oligomeric ozonolysis products whereas alcohols and/or mixtures of ethyl acetate with alcohols for the ozonolysis of canola oil do not form high molecular weight compounds. In addition, when ethyl acetate is used as the solvent, the formation of carboxylic acids is observed in the early stages of ozonolysis whereas the use of alcohols significantly reduces acid formation. As expected, extending the ozonolysis time led to extensive carboxylic acid formation, especially using ethyl acetate as a solvent. It was found that the optimum time for the complete ozonolysis of canola oil was largely independent of the solvent used for ozonolysis. However, the yield of ozonolysis products differs considerably depending on the solvents employed. Overall, a clear correlation between the ozonolysis time, product yields and the reaction exothermicity was observed.