I get Gas chromatography results as 95% thiol purity and after some hours impurity is formed was noted in GC. We analysis the impurity that is DIMER of thiol. Can anyone give me suggestion.. how to avoid dimerization in thiol synthesis.
You should do the synthesis in an inert atmosphere like N2 or Ar to avoid the oxidation of sulfur. Thiols get easily oxidized in the presence of oxygen.
You should run the reaction under argon or nitrogen atmosphere. THe compund should be stored under argon or nitrogen or you add Dithiothreitol (DTT) as stabilizer.
I am doing the reaction in N2 Atmosphere even though i face the same problem sir.
Not only you should work under N2 or Ar atmosphere, the solvent also should be dried and de-oxygenated before use.
The best option, as listed above is DTT, failing that the S-S bond can be reduced using NaBH4, though this may cause problems if there are incompatible functional groups. UV can also be a problem for thiols, maybe exclude light as well as O2 and see if the impurity takes longer
Store your compound in a nitrogen atmosphere at -20 degree. I hope this will solve your problem.
If problem still there you can prepare thioester that are stable even at room temperature over long period of time.
If you are storing your compound in solution, keeping the pH low (well below the pKa of the thiol) will generally limit disulfide bond formation due to O2.
Every thiol is able to oxidize to disulfide from the oxygen in the air.
Immediately distill off the thiol and store in deoxygenated atmosphere in brown bottle.
Inert gases should be used. Proper storage under vacuum right after the reaction.
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