DMSO is a starting material for trimethylsulfoxonium bromide (TBM, CAS 25596-24-1). It reacts with methyl bromide to form the salt, so part of the DMSO charged to the process becomes the product.
From DMSO to TBM
The simplified reaction is:
DMSO + methyl bromide → trimethylsulfoxonium bromide.
After reaction, the salt is isolated and processed through operations such as filtration, washing and drying. TBM can then be used as a precursor to sulfur ylides in further organic synthesis.
TBM is a sulfoxonium salt. It is chemically different from trimethylsulfonium bromide, another sulfur-containing reagent used in synthesis.
Why water content matters
Water content is a controlled variable in documented TBM production routes. One published process specifies no more than 400 ppm water in the starting DMSO and describes tighter preferred limits. The appropriate purchase specification depends on the process being operated.
If the process requires 100 ppm or 50 ppm, state that numerical limit when ordering and confirm the supplier's specification and availability. Keep the material sealed and limit contact with humid air during sampling and transfer. A low incoming water result is useful only if handling preserves it.
Batch charge and fresh consumption are different
Some DMSO is converted into TBM, while excess material can remain in the mother liquor and be recovered. DMSO may also be used in washing. These uses explain why total batch charge can be considerably higher than fresh make-up demand.
Plan purchases around fresh consumption, recovery losses and campaign requirements. Recovered DMSO needs acceptance criteria covering water and process-related impurities before reuse.
The DMSO–methyl bromide system also requires assessed temperature and decomposition controls, together with appropriate methyl bromide containment and handling procedures.
For DMSO enquiries for TBM production, share your water limit, required quantity and packaging with YUJI.
Technical references
Further reading: DMSO in Corey–Chaykovsky Epoxidation; DMSO in Wittig Reactions.