Premium
Microwave Heating Outperforms Conventional Heating for a Thermal Reaction that Produces a Thermally Labile Product: Observations Consistent with Selective Microwave Heating
Author(s) -
Duangkamol Chuthamat,
Batsomboon Paratchata,
Stiegman Albert E.,
Dudley Gregory B.
Publication year - 2019
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201900625
Subject(s) - microwave heating , microwave , dielectric heating , thermal , materials science , electric heating , electromagnetic heating , heating system , joule heating , product (mathematics) , nuclear engineering , thermodynamics , composite material , electrical engineering , physics , telecommunications , computer science , engineering , geometry , mathematics , electromagnetic coil
Abstract Microwave (MW) heating is more effective than conventional (CONV) heating for promoting a high‐temperature oxidative cycloisomerization reaction that was previously reported as a key step in a total synthesis of the natural product illudinine. The thermal reaction pathway as envisioned is an inverse electron‐demand dehydro‐Diels–Alder reaction with in situ oxidation to generate a substituted isoquinoline, which itself is unstable to the reaction conditions. Observed reaction yields were higher at a measured bulk temperature of 200 °C than at 180 °C or 220 °C; at 24 hours than at earlier or later time points; and when the reaction solution was heated using MW energy as opposed to CONV heating with a metal heat block. Selective MW heating of polar solute aggregates is postulated to explain these observations.