Synthesis of Novel Vegetable Oil-Derived Polythiols and Their Thermosets

Due to the ongoing depletion of fossil resources, the use of renewable raw materials for the development of new chemical processes has received increasing attention. Herein, we present a novel synthetic method for the production of renewable polythiols from vegetable oils. Two types of sunflower oil with different fatty acid compositions as well as a triglyceride prepared from biobased undecenoic acid and glycerol were used as starting materials. The three-step synthesis protocol involves catalytic reduction of the triglyceride ester moieties to ethers, followed by conversion of the carbon–carbon double bonds of the fatty acid substituents to thiols via thiol–ene addition of thioacetic acid and subsequent alcoholysis. Polythiols were obtained in overall yields ranging from 58 to 73%, and their feasibility for applications as cross-linkers in the synthesis of polymeric networks was exemplarily demonstrated. Furthermore, all synthetic steps were optimized considering the principles of Green Chemistry, relying on bulk syntheses, simple reaction setups and workup methods, as well as benign and cheap materials as far as feasible.