Chlorosulfonyl isocyanate

Synonyms：CSI; Sulfurisocyanatidoyl chloride

CAS No.：1189-71-5

EINECS No.：214-715-2

Molecular Formula：CClNO3S

Molecular Weight：141.5336

Structural Formula：

Standard：

Properties：Chlorosulfonyl Isocyanate is a colorless transparent liquid with an irritating odor and high corrosivity. It has a strong irritating effect on the respiratory tract and skin; it is highly hygroscopic and can form fumes when exposed to air; it reacts violently with water, decomposing into sulfamic acid, hydrogen chloride and carbon dioxide. This product is insoluble in water but soluble in non-polar or weakly polar organic solvents such as oxolane, chlorinated hydrocarbons, ethers and acetonitrile. Density: 1.626 g/cm³ (25 °C), Melting point: -44~-43℃, Boiling point: 107~108°C, Flash point: >110 °C (closed cup).

Applications：Chlorosulfonyl Isocyanate (CSI) is a key organic synthesis intermediate with dual reactive activity. Leveraging the unique chemical properties of chlorosulfonyl and isocyanate groups, it is widely used in high-value fields such as pharmaceuticals, agrochemicals, polymer synthesis, and battery materials. Its core applications are as follows:

1. Core Intermediate for Pharmaceutical Synthesis: Used in the industrial synthesis of cephalosporin antibiotics including cefuroxime and cefoxitin; participates in the total synthesis of the antidepressant (+)-sertraline and the stereoselective amination of chiral compounds. It can prepare sulfonamide compounds with carbonic anhydrase inhibitory activity, laying the foundation for new drug research and development. Meanwhile, it enables the one-pot conversion to synthesize carbamates, meeting the synthesis needs of pharmaceutical products such as neuromodulators.
2. Raw Material for Agrochemical Synthesis: Serves as a core raw material for the synthesis of sulfonylurea herbicides (e.g., metsulfuron-methyl, bensulfuron-methyl, cyclosulfamuron) and a key intermediate precursor for insecticides like thiamethoxam. Widely adopted by enterprises such as Bayer and BASF in the production of sulfonyl-containing agricultural active ingredients, it helps enhance the activity and targeting of pesticides.
3. Organic and Polymer Synthesis Field: Participates in various organic reactions including lactam formation, sulfonylation, and cycloaddition; used in the preparation of amides, triazocines, and N,N-disubstituted sulfonamides. It is an important raw material for synthesizing high-performance resins, elastomers, surfactants, and special catalysts, as well as a precursor for Burgess reagent, suitable for fine organic synthesis and special polymer preparation needs.
4. Battery Material Precursor: Used in the synthesis of high-performance lithium battery electrolyte salt Lithium Bis(fluorosulfonyl)imide (LiFSI), providing key structural units. It helps improve the ionic conductivity and stability of lithium battery electrolytes, meeting the high-end needs of the new energy battery material field.
5. Fine Chemicals and Textile Auxiliaries: Acts as a dehydrating agent and oxidizing agent in fine chemicals, capable of undergoing addition reactions with alcohols, phenols, carboxylic acids, etc., to generate high-value-added compounds. As a raw material for textile auxiliary synthesis, it is used in fiber modification (imparting antistatic properties) and penetrant preparation, improving the dyeing uniformity and adhesion effect of textiles.

Storage：Store in a cool, dry and well-ventilated place. Keep away from heat sources, fire sources, and direct light.

Packing：50kg or 80kg steel-plastic composite barrel