Pressure bombs (release valves not shown)
Since the mid 1980's, we have experimented with numerous reactions to see whether they
can be performed more efficiently in conventional microwave ovens.
A number of these have given significant reduction in heating times without any
appreciable loss of yield or purity.
For example, see the preparation of Cr(acac)3 in the C 21J
Laboratory Manual.
We have used 60 and 120 mL Teflon bombs purchased from:
Savillex Corporation, 6133 Baker Road, Minnetonka, Minnesota, 55345 USA Tel (612) 935-4100 Fax (612) 936-2292
this is not a commercial, but, compared to other brands we have tried, only a few have
exploded on us over the years!!
In their Catalog #15, 1994 page 27, they quote prices of:
$ 91.20 for 4 of the 60 mL vessels (#561R2) $167.20 for 4 of the 60 mL vessels (#568) with pressure relief valves, $121.60 for 4 of the 120 mL vessels (#571R2). $193.80 for 4 of the 120 mL vessels (#578) with pressure relief valves.
In general, students are warned not to fill to more than about 10% of the volume of the container so as to allow a fairly large head-space.
In the Chromium preparation mentioned above, the conventional heating time is over three hours, whereas in the microwave oven, the product precipitates in the Bomb within five minutes.
For our paper presented at ECTOC see here.
For further details see:
H.M. Kingston and L.B. Jassie, "Introduction to Microwave Sample Preparation- Theory
and Practice", American Chemical Society, Washington D.C., USA, 1988.
D.R Baghurst, D. Michael and D.M.P. Mingos, Chem. Soc. Rev., 1991,20, 1-47.
and look at the WWW site on the use of Microwave Ovens in sample preparation here.
On theCEM web site you can find details of their MARSX
equipment for solvent extraction at elevated temperatures and pressures as well as
Carboflon(R) inserts for heating non-polar solvents.
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Created and maintained by Dr. Robert J. Lancashire,Created Feb 1995. Last modified 13th December-98.
URL http://wwwchem.uwimona.edu.jm:1104/lectures/coffee.html