Ultrasound for use in chemical reactions is generated by an electromagnet formed from an ultrasound transducer whose central feature is a loop of magnetostrictive material wound with coils oriented to produce an oscillating magnetostrictive force when an oscillating voltage is applied. The oscillations in the transducer loop are transmitted to an ultrasonic horn that is immersed in a reaction medium where the ultrasonic vibrations are transmitted directly to the reaction mixture.