Journal
JOURNAL OF ORGANIC CHEMISTRY
Volume 79, Issue 16, Pages 7437-7450Publisher
AMER CHEMICAL SOC
DOI: 10.1021/jo501153r
Keywords
-
Categories
Funding
- COFRS grant from the FSU Research Foundation
- National Science Foundation [NSF-CHE 0911080, NSF-CHE 1300722]
- Direct For Mathematical & Physical Scien
- Division Of Chemistry [1300722, 1112046] Funding Source: National Science Foundation
Ask authors/readers for more resources
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.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available