08-18-03 05:44
No 454269
Microwave adjusting ...
Is it possible to shift the frequency of a standard microwave ?
So that it might be tuned to the resonant frequency of a specific Non-Polar solvent..
anyone ?
(Chief Bee)
08-18-03 13:16
No 454332
No. And besides, microwaves does not operate on the principle of vibrating molecules at their resonant frequencies, they merely heat them by friction due to just any vibration. Molecules in solution have so much differing environments that they have no single resonant frequency.
(Hive Bee)
08-18-03 23:46
No 454411
the friction is caused by polar reversal. which is a function of motion could be conscrued as vibration only not just oscillation more movement.
(Newbee)
08-19-03 01:51
No 454422
beebo has noticed, when attempting to boil NP solvent in the MW oven, that it is very difficult and sometimes not possible...
What is the reason for this and can a microwave be adjusted or modified for boiling the NP sol's...
beebo is just about to resort to a double boiler appraoch that has a High BP solvent like Automotive antifreeze in the boiler: and just heat the NP sol with the boiler..
thanks
moose
(Chief Bee)
08-19-03 02:38
No 454429
Non-polar solvents are simply transparent to microwaves, and you can't to anything to the oven to change that.
Take a look at the table in ../rhodium/pdf /solvent.misci
The "polarity index" is a rough comparative estimate on how effectively different solvents are heated by microwaves. As you can see, Water has an index of 9, while pentane/hexane has a 0. Toluene/Xylene is at a very low ~2.4-2.5.
(Newbee)
08-19-03 04:34
No 454443
have a restriction.
Rotational transitions are only observed in the spectrum if the molecule has a permanent dipole moment. The reason for this is that the rotational motion must involve an oscillating dipole, which can interact with an electromagnetic field, there will be no absorption or emission if otherwise.
This means , as far as linear molecules are concerned, that molecules with a center of symmetry such as N2 and C2H2, or even pentane/hexane do not have a pure rotationnal spectrum whereas those without a center of symmetry, for example HF, do have a rotational spectrum.
So you understand that putting for example hexanes in the microwaves, even if you heat for 1 month, wont do a thing.
But think about it, if you change the frequency, so will the wavelenght and maybe you wont be in the microwave region anymore...
(Hive Bee)
09-08-03 01:15
No 457651
something can be done to transfer heat to non-polar solvents in a microwave. simply use a polar material to either radiate, induce, or convect the heat as in contact with non-polar vessel.
there's a guy on the net who melts metals with MW on a small scale.
(Stranger)
09-09-03 03:47
No 457818
Good grief............just put it in one of those earthenware dishes that get way hot and the food stays cool. It will boil in short order. Just don't blow yourself up and use a cover.
(Hive Adickt)
09-09-03 08:34
No 457861
Usual your reactan's will absorm MW, and that is enough. the solvent is more for cooling than boiling.