Batch and continuous-flow preparation of biodiesel derived from butanol and facilitated by microwave heating

The batch and continuous-flow preparation of biodiesel derived from vegetable oil and 1-butanol using a commercially available scientific microwave apparatus is reported. The methodology allows for the reaction to be run under atmospheric conditions and, in continuous-flow mode, can be performed at flow rates up to 2.3 L/min using a 4 L reaction vessel. It can be utilized with new or used vegetable oil with 1-butanol and a 1:6 molar ratio of oil to alcohol. Sulfuric acid or potassium hydroxide can be used as the catalyst.