Facile Modification of Propiolated Castor Oil via Nucleophilic Thiol-Yne Click Reactions

The combination of modern click protocols and bio-based building blocks is a great step toward energy-efficient, and sustainable polymer production. Herein, thiol-Michael addition (thiol-yne) reactions from the toolbox of click chemistry protocols are chosen and propiolated castor oil (PCO) is used, a vegetable oil derivative, as the bio-based building block for the facile functionalization of PCO with various thiols. In addition to the functionalization of PCO, hyperbranched and crosslinked polymers are also prepared. The thiol-yne click functionalization reactions of the PCO are conducted at room temperature within 5 min and in the presence of an organic catalyst. The yields are found to change between 80% and 99% depending on the type of the thiol compound. The effect of various organic catalysts is investigated, and 1,8-diazabicyclo(5.4.0)undec-7-ene (DBU) is found to be the most effective catalyst for the thiol-yne modification reactions. The hyperbranched polymer reaches 23.8 kDa (M_w) within 5 min. The findings of this paper open up new horizons for polymer researchers who work in the field of sustainable polymers and click chemistry and the presented idea here is appealing because it offers a potential strategy for fast, reliable, modular, and functional macromolecule preparation from renewable vegetable oils.