USE OF CONTINUOUSLY VARIABLE POWER IN MICROWAVE ASSISTED CHEMISTRY

• Main Authors: GREENE, GARY ROGER, BARCLAY, DAVID ALLAN
• Format: Patent
• Language: English; French
• Published: 28.10.1999
• Edition: 6
• Subjects: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOIDCHEMISTRY; ELECTRIC HEATING; ELECTRIC LIGHTING NOT OTHERWISE PROVIDED FOR; ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; MEASURING; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; PHYSICS; TESTING; THEIR RELEVANT APPARATUS; TRANSPORTING

A method of microwave assisted chemistry is disclosed in which power can be supplied more continuously at preferred power levels to more precisely control or moderate a chemical reaction. The method comprises measuring the duty cycle required to maintain a measured selected parameter of a sample at a predetermined set point while the sample is being exposed to microwave radiation at a first predetermined power level; and moderating the duty cycle and the applied microwave power to increase the on time of the duty cycle while applying power at a second predetermined power level that is sufficient to maintain the sample at the set point using the moderated duty cycle. A corresponding device (10) for microwave assisted chemistry is also disclosed and comprises a cavity (11) for receiving a sample (16), a waveguide (12) connected to the cavity (11), a source of microwave radiation connected to the waveguide (12), and a switching power supply (17) for driving the source of microwave radiation (13).