1400935-01-4Relevant academic research and scientific papers
Microwave-specific acceleration of a friedel-crafts reaction: Evidence for selective heating in homogeneous solution
Rosana, Michael R.,Hunt, Jacob,Ferrari, Anthony,Southworth, Taylor A.,Tao, Yuchuan,Stiegman, Albert E.,Dudley, Gregory B.
, p. 7437 - 7450 (2014)
Thermally promoted Friedel-Crafts benzylation of arene solvents has been examined under both conventional convective heating with an oil bath and heating using microwave (MW) energy. Bulk solution temperatures-as measured by internal and external temperature probes and as defined by solvent reflux-were comparable in both sets of experiments. MW-specific rate enhancements were documented under certain conditions and not others. The observed rate enhancements at a given temperature are proposed to arise from selective MW heating of polar solutes, perturbing thermal equilibrium between the solute and bulk solution. Central to MW-specific thermal phenomena is the difference between heat and temperature. Temperature is a measure of the ensemble average kinetic molecular energy of all solution components, but temperature does not provide information about solute-specific energy differences that may arise as a consequence of selective MW heating. Enhanced chemical reactivity of the MW-absorbing solute can be described as a MW-specific extra-temperature thermal effect , because the measurable solution temperature only captures a portion of the solute kinetic molecular energy. Experimental factors that favor MW-specific rate enhancements are discussed with an eye toward future development of MW-actuated organic reactions, in which the observed thermal reactivity exceeds what is predicted from temperature-based Arrhenius calculations.
Microwave effects in organic synthesis: Myth or reality?
Kappe, C. Oliver,Pieber, Bartholomaeus,Dallinger, Doris
supporting information, p. 1088 - 1094 (2013/03/13)
It's not magic! The effects observed in microwave-irradiated chemical transformations can in most cases be rationalized by purely bulk thermal phenomena associated with rapid heating to elevated temperatures. As discussed in this Essay, the existence of s
