What is COS, how is it produced, and what are its physical properties?

Chinese name: Carbonyl sulfide; English name: Carbonyl sulfide； Carbon oxysulfide, also known as carbonyl sulfide ； carbonyl sulfide ； Carbon oxysulfide has the molecular formula COS. It is a colorless, foul-smelling gas that is hygroscopic; it decomposes into carbon monoxide and sulfur at 300°C. It can be rapidly absorbed and decomposed by potassium hydroxide. Molecular weight: 60.07. Vapor pressure: 1204.23 kPa at 21°C. Flash point: < -50°C. Melting point: -138.2°C. Boiling point: -50.2°C. Solubility: Highly soluble in water, as well as in ethanol and toluene. Density: Relative density (water = 1): 1.24 at -87°C (liquid state) ； Relative density (air=1): 2.1 Stability: Stable. Hazard symbol: 6 (toxic gas). Main uses: Synthesis of sulfur-containing organic compounds. I. Health hazards: Route of exposure: Inhalation. Health hazards: This product has a mild irritant effect on the lungs; it primarily acts on the central nervous system. In cases of severe poisoning, it can cause convulsions and even respiratory paralysis leading to death. II. Toxicological data and environmental behavior Hazardous characteristics: Can form explosive mixtures when mixed with air. It can catch fire and explode in the presence of open flames or high heat. It reacts violently with oxidizers. Reacts with water or water vapor to release toxic or flammable gases. Combustion (decomposition) products: carbon monoxide, hydrogen sulfide, sulfur oxides.

　Carbon disulfide (Carbonyl Sulfide) 1. Uses: Used in the synthesis of carbon oxides, thioacids, thiocarbonates, and thiazoles; also serves as a fumigant for storing grains and wood and for sterilization purposes. 　　2. Physical and chemical properties Melting point: -138.20°C (100 kPa) ； 　　Boiling point: -50.20°C (101.325kPa) ； 　　Liquid density: (-5.2°C, 101.325 kPa) 1178 kg/m3 ； 　　Gas density: (101.325 kPa, 20°C) 2.527 kg/m3 ； 　　Relative density: (101.325 kPa, 20°C, air = 1) 2.10 ； 　　Specific volume: (101.325 kPa, 21.1°C), 0.402 m3/kg ； 　　Gas-liquid volume ratio: (15°C, 100 kPa) 464 L/L ； 　　Critical temperature: 102℃ ； 　　Critical pressure: 5877kpa ； 　　Critical density: 429 kg/m3 ； 　　Heat of fusion: 78.660KJ/kg ； 　　Heat of vaporization: △Hv(-50.2℃)=380.07Kj/kg Specific heat capacity (gas, 101.325kpa, 25℃): Cp=711.7J/(kg·K) Cv=573.2J/(kg·K) ； 　　Specific heat ratio (gas, 101.325 kPa, 25°C): Cp/Cv=1.241 ； 　　Vapor pressure: -81°C, 18.572 kPa; 0°C, 618.08 kPa; 40°C, 1824 kPa ； 　　Viscosity (gas, 101.325 kPa, 0°C): 0.01166 mPa·s ； 　　Surface tension (-69.5°C): 0.02406 N/m ； 　　Thermal conductivity (gas, 101.325 kPa, 25°C): 0.01088 W/(m·K) ； 　　Combustion limit in air (20°C, 100 kPa): 12%–29% ； 　　Solubility in water (101.325 kPa, 0°C): 1.333 cm3 per 1 cm3 of H2O ； 　　Flammability level: 3 Toxicity level: 3 Reactivity level: 2 At normal temperature and pressure, it is a colorless, flammable, toxic gas with an unpleasant odor similar to that of rotten eggs. It can be transported as liquefied gas; at 21.1°C its S.P. is 1204.5 kPa. When mixed with oxygen, it forms an explosive gas, and upon contact with bromine water or potassium permanganate, it reacts to produce CO2 and sulfuric acid. It is reduced by hydrogen to release CO and H2S, and reacts slowly with water to release CO2 and H2S. When heated, it decomposes in the following two ways: COS → CO + S ； 　　2COS→CO2+CS2

This is the area for discussing gasification technology; therefore, from a professional perspective, CO produced during the gasification process reacts with sulfur, a trace element present in coal, to form COS.