Small molecule sulfides, large molecule sulfides

Both small-molecule sulfides and large-molecule sulfides are different forms of sulfur compounds found in chemical substances. Small molecular sulfides generally refer to simple compounds composed of a few atoms, such as hydrogen sulfide (H2S), carbon disulfide (CS2), and so on. These compounds have a low molecular weight, are chemically reactive, and are volatile. They are widely present in nature; for example, hydrogen sulfide is released during volcanic eruptions, in groundwater, and as part of the metabolic processes of certain microorganisms. Macromolecular sulfides are high-molecular-weight compounds formed by the covalent bonding of many small molecular sulfides together. For example, rubber and vulcanized butyl rubber (natural rubber) are macromolecular sulfides composed of many vulcanized butylene molecules. These compounds are more difficult to volatilize in nature than small molecular sulfides, and they are usually found in heavier substances such as petroleum, coal, rubber, and other materials. In general, small molecular sulfides and large molecular sulfides are different forms of sulfur compounds, and their existence form depends on their molecular weight and chemical properties. .

Small-molecule sulfides and large-molecule sulfides refer to the forms in which thioether compounds (i.e., sulfides) exist in oils. Generally speaking, small-molecule sulfides are relatively easy to oxidize and evaporate, and they also disperse readily in petroleum products. Therefore, they typically occur in lighter fractions, such as gasoline, jet fuel, etc. At the same time, the content of small molecular sulfides is also high, and desulfurization treatment is usually required to meet emission standards. Due to their relatively large molecular weights, macromolecular sulfides generally exist in oils in the form of tiny solid particles or polymers of long-chain molecules. They are difficult to disperse, as well as difficult to oxidize and evaporate. Therefore, macromolecular sulfides are typically found in heavier components, such as diesel. .