A robust microwave-absorbing solid alkaline catalyst synthesis via CaSr-BTC for green and efficient biodiesel production

• A robust microwave-absorbing catalyst is synthesized via bimetallic organic frameworks CaSr-BTC. • Sr enhances the electrophilic reactivity of CaO exhibiting stronger catalytic activity. • CaSr-800 possesses strong dielectric property with ε r = 26.91–27.47j and tanδ ε = 1.021. • CaSr-800 could reduce energy consumption by 85.71 % with TOF of 317.46h −1 . • Microwave absorbing ablity of catalyst is proved to boost catalytic performance. Microwave heating has been proven to be a powerful tool for enhancing transesterification for biodiesel production. Current research mainly focuses on the interaction between microwaves and the reactant, neglecting the effect of catalyst-microwave interaction. In this study, nanosheet-like Ca 0.9 Sr 0.1 O/C composite (CaSr-800), a robust microwave-absorbing catalyst, is synthesized via the bimetallic organic frameworks CaSr-BTC. The catalytic performance is compared between conventional heating (CH) and microwave heating (MWH) to reveal the effect of microwave absorbing capacity of catalyst. Results show that CaSr-800 in-situ converted microwave energy into thermal energy with ε r = 26.91–27.47j and tanδ ε = 1.021. With that, biodiesel production with palm oil conversion of 99 % was achieved in merely 15 min under 200 W microwave field with turnover frequency of 26.76h −1 , which subsequently reduced energy consumption by 85.71 % in comparison to CH method.