bluecurry
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High B.P. solvents?
I've been trying to find information on the boiling points of solvents, in particular I'm trying to find out about solvents with high boiling points.
Any help would be appreciated.
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DJF90
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How high do you have in mind? DMSO and DMF are pretty high boiling( ~190C and 150C repsectively). Also xylene (~140C). Cant think of any others off
the top of my head. Generally its useful to have a low boiling solvent to facilitate easy removal from the product after the reaction.
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hissingnoise
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The mononitrotoluenes have B.Ps above 220*C. . .
They're not everyday solvents, obviously!
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DJF90
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Mononitrotoluenes are hardly usable as solvents. I can't think of a single reaction that would call for their use. Bit of a ridiculous suggestion if
you ask me...
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kclo4
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well it depends on what you are dissolving or doing with it. I'm sure somewhere they have a use. bluecurry might be wanting to use these high boiling
point solvents to dehydrate something for all we know.
bluecurry, what are you trying to dissolve?
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bluecurry
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I am interested in understanding the effects of various high B.P. solvents on thermal rearrangement in the synthesis of various aminoketone's.
175-225C seems to be the optimum boiling point range required in most of what I've read.
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Paddywhacker
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Yes, we need more information about the application.
Other solvents .... paraffin oil or wax, polyethylene glycol, glycerol, triglycerides. Biodiesel (fatty acid methyl esters) make a good high-temp
solvent. Silicone oils. Molten eutectic salt mixtures. Molten eutectic alloys. Supercritical water.
Really depends on what you want to do.
Edit:-
Damn, Bluecurry, you beat me to the keyboard.
So, you are looking for something that will be easy to separate from your reaction products.
[Edited on 2-5-2009 by Paddywhacker]
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hissingnoise
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Quote: Originally posted by DJF90  | | I can't think of a single reaction that would call for their use. Bit of a ridiculous suggestion if you ask me... |
Well, now you know---your knowledge-base, such though it is, is infinitely expansible. . .
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bluecurry
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Optimally, yes. While I was discussing things with a friend, he was mentioning how a common problem with thermal rearrangements are byproducts which
can cause numerous hurdles in obtaining a pure end product.
We've been sort of brainstorming on the possibilities of using different solvents to understand how to better remedy such a problem.
Acetone could be used for cleaning up the substance I suppose, but is useless for a high temperature application and would simply add excessive steps.
[Edited on 2-5-2009 by bluecurry]
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DJF90
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I searched online and could find no mention of monotoluenes use as a solvent. Do you have a reference for that? 
[Edited on 2-5-2009 by DJF90]
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bluecurry
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I believe I might have answered my own question but I need to look into it more.
Methyl benzoate seems to be a viable solution, along with a few other esters. Would I have to worry about any side reactions occuring in the presence
of an acid (or base for that matter) due to nature of the solvent?
[Edited on 3-5-2009 by bluecurry]
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not_important
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Esters can be fairly reactive, for instance reacting with amines to form amides. Nitro compounds can act as oxidisers
Solvents actually used include technical 1,2 dichlorobenzene, di-, tri-, and tetra- ethylene gylcol and the corresponding mono- (cellosolves and
carbitols) and di- ethers with the diethers being aprotic.
On this page http://www.dow.com/productsafety/finder/dgbe.htm in the "Additional Information" section there are lnks to PDFs such as Dow's Glycol Ethers
brochure and Solvent Property Tables. The glycol ethers are generally solubile in water or water-alcohol mixtures, allowing a product to be
precipitated from the reaction mix by pouring it into water.
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watson.fawkes
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| Quote: Originally posted by not_important | | Solvents actually used include technical 1,2 dichlorobenzene, di-, tri-, and tetra- ethylene gylcol and the corresponding mono- (cellosolves and
carbitols) and di- ethers with the diethers being aprotic. |
Doesn't this class of chemicals include DOT 3
brake fluid?
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hissingnoise
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| Quote: Originally posted by DJF90 | | I searched online and could find no mention of monotoluenes use as a solvent. Do you have a reference for that? |
No ready refs DJF90, but nitrotoluenes have been used for their solvent properties.
Few chemists would relish working with boiling nitrotoluene, but there are some procedures where its use is a necessary evil. . .
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Nicodem
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| Quote: Originally posted by bluecurry | | I am interested in understanding the effects of various high B.P. solvents on thermal rearrangement in the synthesis of various aminoketone's.
175-225C seems to be the optimum boiling point range required in most of what I've read. |
The solvents suitable for the use in the synthesis of ketamine starting from the precursor sold by the Chinese & their friends was already
discussed several times on this forum. How about UTFSE before posting?
Besides, how can you think anybody could suggest you an alternative solvent without explaining what reaction you want to use it for? Do you think that
the boiling point is the only important property of a solvent? If so, you have still a lot to learn about chemistry and immediately jumping on
ketamine synthesis is maybe not the wisest decision.
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
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Siddy
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sugar alcohols are useful, otherwise DMSO as some else said. All easy to get your hands on.
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497
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I've always though methylsulfonylmethane would be an interesting high temp solvent. Boiling at 238*C and being less reactive than DMSO, it must be
useful for something.
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Panache
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| Quote: Originally posted by 497 | | I've always though methylsulfonylmethane would be an interesting high temp solvent. Boiling at 238*C and being less reactive than DMSO, it must be
useful for something. |
Its an excellent solvent! Cheap, easily removable by dumping in water, inert, non-toxic.
However if its simply the thermal rearrangement that is of interest, i suggest using a silicon oil. I mean you can ensure minimal solvent effects so
your study results would be more sincere. At higher temperatures its viscosity is decreased, so heavy stirring would ensure appropriate dispersal. In
theory there is no reason you couldn't run up until 400C, given it would be a one shot use anyways. To remove your organics post reaction you could
vacuum distill them out or solvent extract them with alcohol, but the viscosity at lower temperatures would make doing this tedious.
For the purists, technically, the silicon oil would not be acting as a solvent here, rather as a heat transfer fluid.
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