Description

DMDS (Dimethyl Disulfide, CH₃SSCH₃, CAS 624-92-0, molar mass 94.20 g/mol) is produced to a minimum purity of 99.5%, tested against internal standard Q/370703AJS 007-2024. Refineries and plants use DMDS primarily as a catalyst sulfiding agent, shipped worldwide in drums and ISO tanks.

How DMDS Sulfiding Works

Hydrotreating and hydrocracking catalysts contain metal oxide sites. Before these catalysts can promote desulfurization and denitrification reactions, the oxide sites must first convert to their active metal sulfide form. To achieve this, refineries inject DMDS directly into the reactor, where it decomposes into hydrogen sulfide (H₂S). The H₂S then reacts with the metal oxides on the catalyst surface, converting them into active metal sulfides.

Notably, this decomposition happens in two separate stages rather than all at once. As a result, temperature spikes during sulfiding become less likely, which lowers the risk of damaging the catalyst bed before it’s fully activated.

DMDS Compared with Other Sulfiding Agents

Compared with dimethyl sulfide (DMS), DMDS carries a higher sulfur content per unit weight. Therefore, less product is needed to reach the same sulfiding target, reducing both handling volume and cost per cycle. Beyond catalyst sulfiding, DMDS is also used to passivate furnace tubes in ethylene steam crackers, where it helps limit coke and carbon monoxide buildup on the coil surface and extends the run length between decoking cycles.

Certificate of Analysis — Typical Results

The table below reflects verified results from a Certificate of Analysis, tested against standard Q/370703AJS 007-2024. A batch-specific Certificate of Analysis is issued with every shipment, so buyers can confirm purity before the product leaves the facility.

Every batch is tested before release, with full tracking from raw material to shipment. For chemistry background, see Wikipedia’s overview of dimethyl disulfide.

Reference Data

• CAS Number: 624-92-0
• Molecular Formula: CH₃SSCH₃ (C₂H₆S₂)
• Molar Mass: 94.20 g/mol

Handling and Safety

DMDS is a hazardous, flammable liquid. Handle, store, and transport it strictly according to its Safety Data Sheet. Full SDS documentation, along with the rest of the MSDS, TDS, and COA library, is available on request.

Packaging and Ordering

DMDS is supplied in the following formats:

• Steel drums, for smaller or trial orders
• ISO tank containers, for bulk refinery-scale shipments

See TBPS (Di-tert-Butyl Polysulfide), the other primary sulfiding agent, to compare and choose whichever fits your catalyst sulfiding program better. Browse the full Sulfiding Agents range, or request a quote for DMDS pricing and lead times.