solvent and a non-polar solvent obtain different temperatures. Applied in a phase transfer reaction a water phase reaches a temperature of 100 °C while a chloroform phase would retain a temperature of 50 °C, providing the extraction as well of the reactants from one phase to the other. Microwave chemistry is particularly effective in dry media reactions. Microwave effect There are two general classes of microwave effects: Specific microwave effects. Non-thermal microwave effects. A review has proposed this definition and examples of microwave effects in organic chemistry have been summarized. Specific microwave effects are those effects that cannot be (easily) emulated through conventional heating methods. Examples include: (i) selective heating of specific reaction components, (ii) rapid heating rates and temperature gradients, (iii) the elimination of wall effects, and (iv) the superheating of solvents. Microwave-specific effects tend not to be controversial and invoke "conventional" explanations (i.e. kinetic effects) for the observed effects. Non-thermal microwave effects have been proposed in order to explain unusual observations in microwave chemistry. As the name suggests, the effects are supposed not to require the transfer of microwave energy into thermal energy. Such effects are controversial. Catalysis Application of microwave heating to heterogeneous catalysis reactions has not been explored intensively due to presence of metals in supported catalysts and possibility of arcing phenomena in the presence of flammable solvents. However, this scenario becomes unlikely using nanoparticle-sized metal catalysts. References External links AMPERE (Association for Microwave Power in Europe for Research and Education) Microwave Synthesis @ organic-chemistry.org homepages uconn.edu site with microwave equipment and research