Solid base catalyst for synthesizing biodiesel and preparation method and application thereof

The invention discloses preparation of anion-modified solid base and application of the same in biodiesel preparation reaction by a catalytic ester interchange method. The catalyst is directly prepared from metal nitrate, metal oxide and ammonium halide under the alkaline condition by a one-step method. The preparation method is simple to operate, and the catalyst has low cost. In the biodiesel preparation reaction by the ester interchange method, the catalyst has high catalytic activity, good reusability and mild reaction conditions, and does not pollute the environment.