Dimethyl disulfide (DMDS) with the chemical formula C2H6S2 is also known as methyl disulfide and is the simplest disulfide compound. The liquid is yellow to transparent and has an unpleasant smell like garlic. Although the new generation of this substance has a milder smell. This material is used in various industries, which are mentioned below. Compared to other sulphiding agents, DMDS has the highest sulfur content, which reduces the amount of product required to convert oxides into active metal sulphides. It has high thermal stability with low viscosity and is suitable for liquid or gas phase injection.
At low temperature it begins to decompose to H2S, thus eliminating the risks of reducing metal oxides prior to sulphidation. In addition, DMDS decomposes in two steps, minimizing the risk of temperature excursion during sulfidation.
Technical Characteristics
| Chemical Formula | C2H6S2 |
| Other names | Dimethyl disulfide, Methyl disulfide, Methyldisulfide, Dimethyldisulfide, Methyldithiomethane, 2,3-Dithiabutane, DMDS, (Methyldisulfanyl)methane |
| CAS Number | 624-92-0 |
| Purity | More than 99 % |
| Boiling point | 110 C |
| Sulfur content | Max 68 wt% |
| Appearance | Colorless liquid |
Applications
- Sulfiding agent in oil refining industries
- Prevent coke and carbon monoxide formation
- Production of pesticides
- Aromaticization of hydrocarbon fuels
- As an additive to food (food grade)
- Agriculture
Environmental impact of DMDS
When decomposed or burned, DMDS may turn into toxic gases such as sulfur dioxide (SO₂), which can cause air pollution and respiratory problems.
Safety Measures and Regulations for Handling DMDS
Due to its low vapor pressure, DMDS is a safe product to handle above ambient temperature. It has a low flash point, so it should be treated as a flammable substance and kept in neutral conditions and away from possible sources of ignition. DMDS is toxic by inhalation and skin contact should be avoided, and is also a marine pollutant.
It may also have a slightly unpleasant smell. DMDS during the sulfidation process produces methane, which, if not properly controlled, may lead to the release of SOx compounds. DMDS is insoluble in water, but is soluble in both amines and ketones. It is compatible with carbon and stainless steel as long as no excess water is present.
Packing
DMDS is packed in ISO Tank, IBC or Drums.