APPLICATIONS OF MICROWAVE IRRADIATIONS
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Transcript APPLICATIONS OF MICROWAVE IRRADIATIONS
APPLICATIONS
Microwave heating is able to heat the target
compounds without heating the entire
furnace or oil bath
This saves time and energy.
However, due to the design of most
microwave ovens and to uneven absorption
by the object being heated, the microwave
field is usually non-uniform and
localized super heating occurs
Microwave heating can have certain
benefits over conventional ovens:
reaction rate acceleration
milder reaction conditions
higher chemical yield
lower energy usage
different reaction selectivities
It is time saving
Increased reaction rates 1000 fold in best
cases
Used to accelerate chemistry in both
solution &solid phase reaction
Improved product yields
It can be conducted in either open or
closed vessels
Access to synthetic transformations not
achievable via conductive heating
Broad dynamic temperature range (45˚c300˚c)
Green chemistry- reactions in supercritical
water or solvent – less reaction
It can be used to accelerate the synthesis of
peptides
It is used for parallel synthesis.
Controlled method of heating
Rapid reaction optimization
In organic reactions
many reactions has now performed
through microwave heating
EXAMPLES:
Acetylation reaction, Alkylation, Coupling reaction,
Condensation reaction, Diel’s alder reaction,
Elimination reaction etc
Heterocyclic Nucleus Synthesis
Microwave is used in synthesis of
Five-Membered Heterocyclic Rings- Pyrroles, Pyrazoles,
Imidazoles, Oxazolines, Triazoles , Isoxazolines etc
Benzo-Derivatives of Five-Membered Rings- Benzimidazoles, Benz-oxazoles, Benz-thiazoles etc
Six-Membered Rings- Dihydropyridines, Tetrazines,
Dihydropyrimidines
Polycyclic Six-Membered Rings- Quinolines,
Pyrimido [1, 2-a] pyrimidines
Heterocyclic C-Alkylations, Heterocyclic N-
Alkylation’s, Nucleophilic Substitutions,
Hetero-Diels-Alder Reactions, Intramolecular
Reactions, Intermolecular Reactions, etc
Synthesis of phenytoin by
conventionalµwave
In conventional synthesis 2 hrs reflux is
needed
In microwave synthesis only 15 minutes
is needed
Yield is better in microwave synthesis
than in conventional synthesis.
Miscellaneous
Microwave assisted Extraction
Microwave Ashing
Microwave drying
The instrumentation developed for
MAOS has
more recently found application in what
has been traditionally termed the
biosciences.
These areas
include peptide synthesis proteomics
and DMPK (dystrophia myotonica
protein kinase) .
Recent publications in the field of
proteomics have shown the instrumentation
used for MAOS can
be used to accelerate tryptic digests with
the total time reduced from hours to minutes
with a concomitant improvement in
coverage.
Highthroughput proteomic applications
may require the development of plate-based
instrumentation to facilitate the work flow.
APPLICATION IN A GIVEN TEMPERATURE RANGE
Ring expansion -45˚c
Coupling reaction
Susbstution reaction etc Super critical water
green chemistry
80-250˚c