Tall oil fatty acids are a second-generation bio-based feedstock finding application in the synthesis of polyurethane materials. The study reported tall oil fatty acids and their methyl esters epoxidation in a rotating packed bed reactor. The chemical structure of the synthesized epoxidized tall oil fatty acids and epoxidized tall oil fatty acids methyl ester were studied by Fourier-transform infrared spectroscopy. Average molecular weight and dispersity were determined from gel permeation chromatography data. The feasibility of multiple uses of the Amberlite® IRC120 H ion exchange resin as a catalyst was investigated. Gel permeation chromatography chromatograms of epoxidized tall oil fatty acids clearly demonstrated the formation of oligomers during the epoxidation reaction. The results showed that methylation of tall oil fatty acids allows obtaining an epoxidized product with higher relative conversion to oxirane and much smaller viscosity than neat tall oil fatty acids. Epoxidation in a rotating packed bed reactor simplified the process of separating the catalyst from the reaction mixture. The Amberlite® IRC120 H catalyst exhibited good stability in the tall oil fatty acids epoxidation reaction. Graphical Abstract

Tall oils are a second-generation feedstock with perspective use in polyurethane materials. This study compared crude tall oil and tall oil fatty acid bio-polyols to determine whether crude tall oil could be used for polyurethane foam production making the production more cost-effective. Polyols were synthesized in a two-step process. At first, double bond epoxidation followed by oxirane ring-opening, and transesterification with multifunctional alcohols. The epoxidation process was studied with acid value and relative conversion to oxirane analysis. The obtained polyols were analyzed for acid value, hydroxyl value, viscosity, and with Fourier transform infrared spectroscopy analysis. The results showed suitable hydroxyl values for almost all polyols, including crude tall oil polyols, but the high viscosity limits the use of most of the polyols.

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