Abstract
Recently there has been a great development of microwave-assisted organic synthesis(MAOS) for use in pharmaceutical industry or synthesis chemistry. In this report it is described how an organic synthesis microwave reactor which uses a temperature control system to heat up organic chemical synthesis reactions was designed and built. The microwave reactor is composed of microwave heating cavity, magnetron, inverter power supply, temperature control system and interface, and pressure valve. The operating principle is inputting PWM (Pulse Width Modulation) signal into the inverter power supply to modulate the output power of microwave. The bigger the duty cycle of input pulse, the stronger the output power of microwave is. The microwave reactor utilizes a thermopile sensor as an analog temperature measurement system to measure the temperature of the reactant. By transforming both the temperature signal of initial reactant and default chemical reaction to voltage signal, the temperature control system use the temperature variation to modulate PWM signal and then feedback control the output power of microwave. This mechanism then heat up the chemical reaction and enable control of the temperature of the chemical reaction.Finally, two chemical synthesis reactions was used, Knoevenagel condensation and Suzuki reaction, to verify the effect of the microwave reactor. The results of the experiments show that the built microwave reactor has very similar result as commercial microwave reactors.