Sciencemadness Discussion Board

polar solvents with C,S, and O?

merrlin - 3-6-2009 at 22:57

Is anybody aware of a compound containing only carbon, sulfur and oxygen that would serve as a liquid polar solvent at room temperature, and a pressure less than 5 atmospheres?

DJF90 - 3-6-2009 at 23:11

DMSO, but it also contains hydrogen ;)

watson.fawkes - 4-6-2009 at 04:54

Sulfur dioxide. Its vapor pressure at 300K is about 4.2 bar. See http://encyclopedia.airliquide.com/Encyclopedia.asp?GasID=27.

DJF90 - 4-6-2009 at 08:18

The bp of SO2 is ca. -10C if I remember correctly. Supposing the solvent cannot contain hydrogen then this will likely be the best option (CO2 and CS2 are linear and as such non-polar). However DMSO is likely a superior choice so long as its constitution is acceptable.

merrlin - 4-6-2009 at 10:04

Quote: Originally posted by watson.fawkes  
Sulfur dioxide. Its vapor pressure at 300K is about 4.2 bar. See http://encyclopedia.airliquide.com/Encyclopedia.asp?GasID=27.


Thanks for the vapor pressure diagram. Sulfur dioxide looks like the leading candidate. What I am looking for is a solvent that can serve as the basis for an electrolyte, while minimizing the presence of magnetic nuclei.

panziandi - 4-6-2009 at 10:48

I have a book, not at hand, that lists various non-aqueous solvents for electrochemistry. Sulphur dioxide is a well documented non-aqueous, polar, solvent for electrochemistry, I expect that you should be able to find ample references to its use as such in teh literature.

JohnWW - 4-6-2009 at 10:57

Quote: Originally posted by merrlin  
Quote: Originally posted by watson.fawkes  
Sulfur dioxide.(cut)

Sulfur dioxide looks like the leading candidate. What I am looking for is a solvent that can serve as the basis for an electrolyte, while minimizing the presence of magnetic nuclei.
You will have to check to make sure whether any of the natural isotopes of sulfur and oxygen, of which there are several, have a net magnetic spin moment; although the most common ones, O-16 and S-32, do not.

merrlin - 10-7-2009 at 17:18

Okay, sulfur dioxide is probably the best solvent. Does anybody have any idea about the solubility of various salts (e.g., uranium sulfate or uranyl sulfate) in sulfur dioxide, relative to water? The dipole moment of sulfur dioxide (1.62 D) is somewhat lower than that of water (1.85 D). Also, I would be interested in information or estimates of the coordination of sulfur dioxide with various cations. Since 95% of sulfur dioxide molecules will be nonmagnetic, coordination as high as six would still provide a nonmagnetic solvation shell for 75% of the cations.

JohnWW - 10-7-2009 at 18:06

"A compound containing only carbon, sulfur and oxygen that would serve as a liquid polar solvent at room temperature, and a pressure less than 5 atmospheres" would also include CS2, which is liquid at 1 atmosphere and room temperature, but its polarity is low. CO2 would also do in the pressure range in which it is a liquid, but at room temperature this may be greater than 5 atm.. COS would also do, being less volatile than CO2, but it still boils at -50ºC at 1 atmosphere, and it would probably be liquid at less than 5 atm. at room temperature.