clearly_not_atara
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Fenton chemistry oxidation of MSM to methanesulfonate
https://link.springer.com/article/10.1007/s00027-003-0673-6
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A laser flash photolysis – long path UV-visible absorption – competitive kinetics technique has been employed to
investigate the kinetics of the aqueous phase reactions between the hydroxyl radical (OH) and three organic sulfur species
[...]
The following Arrhenius expressions adequately summarize the kinetic data obtained over the temperature range 275 – 310 K (units are M–1 s–1):
ln kDMSO = (26.88 ± 0.14) – {(1270 ± 40)/T}; ln kDMSO2 ≤ (22.36 ± 0.17) – {(1690 ± 50)/T}; ln kMS = (25.20 ± 0.13) – {(2630 ±
40)/T}.
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Plugging in T = 275 K (2 C), we find that oxidation of MSM should be about five times as fast as oxidation of methanesulfonate at this temperature. It
is not immediately obvious why the reaction rate would decrease with increasing temperature, but that seems to be what they're saying.
So generating a lot of hydroxyl radicals in a solution containing methanesulfonylmethane (dimethyl sulfone) might be an effective, though not
necessarily well-yielding, route to methanesulfonic acid, a highly desirable acid -- liquid, noncoordinating, nonoxidizing, and stable. Dimethyl
sulfone is widely available due to its popularity among crazy supplement hippies. Pure Me2SO2 melts at 19 C, but it is readily soluble in water.
The raw materials couldn't be easier -- "MSM", hydrogen peroxide, ferrous sulfate, aqueous. The stoichiometry is basically impossible to estimate and
likely depends on reaction rate and concentration, since hydroxyl radical has a very strong tendency to recombine and decompose. Isolating mesylate
will not be easy, since all of its salts are soluble.
Since hydroxyl radical is unstable, the most efficient technique likely involves slowly adding hydrogen peroxide to a solution containing MSM and
catalytic FeSO4.
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chempyre235
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To resurrect an old thread, Quote: Originally posted by clearly_not_atara  | The raw materials couldn't be easier -- "MSM", hydrogen peroxide, ferrous sulfate, aqueous. The stoichiometry is basically impossible to estimate and
likely depends on reaction rate and concentration, since hydroxyl radical has a very strong tendency to recombine and decompose. Isolating mesylate
will not be easy, since all of its salts are soluble.
Since hydroxyl radical is unstable, the most efficient technique likely involves slowly adding hydrogen peroxide to a solution containing MSM and
catalytic FeSO4. |
This is an interesting synthesis. I've often wondered if MSM could be made into mesylate, and apparently it can.
For the solubility and isolation issue, I see a couple of possible approaches. First, cooling and neutralization of mesylate solution with
Ca(OH)2 should yield calcium mesylate (soluble), calcium sulfate (insoluble), and ferric oxide/hydroxide (insoluble or low solubility).
Filtration of the solution, treatment with H2SO4, a second fitration, and distillation should get the pure acid, I think.
A second method would be to add ethanol and sulfuric acid to precipitate the ferric sulfate, followed by vacuum distillation to avoid the formation of
esters or diethyl ether. Could this work?
[Edited on 3/25/2026 by chempyre235]
"However beautiful the strategy, you should occasionally look at the results." -Winston Churchill
"I weep at the sight of flaming acetic anhydride." -@Madscientist
"...the elements shall melt with fervent heat..." -2 Peter 3:10
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