Catalytic hydrogenolysis of castor seeds C-lignin in deep eutectic solvents

The recently discovered catechyl lignin (C-lignin) represents an ideal lignin platform for depolymerization because of its exclusive benzodioxane linkages between caffeyl alcohol monolignols. In this report, we described catalytic hydrogenolysis of castor seed coats by using deep eutectic solvents, where naturally grown C-lignin was extracted from endocarp matrix and depolymerized into monomeric catechols. The production efficiency of catechols from present one-pot manner was comparable to that from a two-step approach. High selectivity towards 4-propyl catechol was observed in DESs reactions, which was complementary to previous reports. This study offered a step-efficient protocol for producing a single, valuable catechol compound from bulk sustainable castor seed coats.