Карбонил сульфид

Химические свойства

Carbonyl sulfide is a colorless gas or cold liquid.

Вхождение

Carbonyl sulfide, COS, is now recognized as a component of the atmosphere at a tropospheric concentration of approximately 500 parts per trillion by volume, corresponding to a global burden of about 2.4 million tons. It is, therefore, a significant sulfur species in the atmosphere. It is possible that the HO• radicalinitiated oxidation of COS and carbon disulfide (CS2) would yield 8-12 million tons as S in atmospheric sulfur dioxide per year. Though this is a small yield compared to pollution sources, the HO•-initiated process could account for much of the SO2 burden in the remote troposphere.
Both COS and CS2 are oxidized in the atmosphere by reactions initiated by the hydroxyl radical. The initial reactions are
HO• + COS ® CO2 + HS• (11.10.1)
HO• + CS2 ® COS + HS• (11.10.2)
These reactions with hydroxyl radical initiate oxidation processes that occur through a series of atmospheric chemical reactions. The sulfur-containing products that are initially formed as shown by Reactions 11.10.1 and 11.10.2 undergo further reactions to sulfur dioxide and, eventually, to sulfate species.

Использование

carbonyl sulfide is use as a fumigant for durable commodities and structures was patented worldwide by Australia in 1992. It is effective on a wide range of pests, including the common stored product species at reasonable concentrations (less than 50 gm-3) and exposure times (1-5 days) . However, the egg stage of several insects showed tolerance to the fumigant. The other problems associated with the use of carbonyl sulfide include its high tainting odour on the treated products and reduction in the germination of seeds. Hydrogen sulphide, an impurity, present in fumigant product supply was reported to be responsible for the off-odour problem. Selective removal of hydrogen sulphide using absorbents like tertiary amine may solve the tainting issues with this fumigant.

Определение

ChEBI: A one-carbon compound in which the carbon atom is attached to an oxygen and a sulfur atom via double bonds.

Общее описание

CARBONYL SULFIDE is a colorless, poisonous, flammable gas with a distinct sulfide odor. The gas is toxic and narcotic in low concentrations and presents a moderate fire hazard. Under prolonged exposure to fire or intense heat the container may rupture violently or rocket. CARBONYL SULFIDE is used in the synthesis of organic thio compounds.

Реакции воздуха и воды

Highly flammable.

Профиль реактивности

CARBONYL SULFIDE is expected to react with vigor with strong oxidants.

Опасность

Narcotic in high concentrations. Flammable, explosive limits in air 12–28.5%. Central nervous system impairment.

Угроза здоровью

TOXIC; may be fatal if inhaled or absorbed through skin. Contact with gas or liquefied gas may cause burns, severe injury and/or frostbite. Fire will produce irritating, corrosive and/or toxic gases. Runoff from fire control may cause pollution.

Пожароопасность

Flammable; may be ignited by heat, sparks or flames. May form explosive mixtures with air. Vapors from liquefied gas are initially heavier than air and spread along ground. Vapors may travel to source of ignition and flash back. Some of these materials may react violently with water. Cylinders exposed to fire may vent and release toxic and flammable gas through pressure relief devices. Containers may explode when heated. Ruptured cylinders may rocket. Runoff may create fire or explosion hazard.

Профиль безопасности

Poison by intraperitoneal route. Mildly toxic by inhalation. Narcotic in high concentration. An irritant. May liberate highly toxic hydrogen sulfide upon decomposition. A very dangerous fire hazard and moderate explosion hazard when exposed to heat or flame. Can react vigorously with oxidizing materials. To fight fire, stop flow of gas or use CO2, dry chemical, or water spray. When heated to decomposition it emits toxic fumes of CO. See also CARBONYLS and SULFIDES.

Возможный контакт

Carbon oxysulfide is an excellent source of usable atomic sulfur, therefore, it can be used in various chemical syntheses, such as the production of episulfides, alkenylthiols, and vinylicthiols. It is also used to make viscose rayon. It is probable that the largest source of carbon oxysulfide is as a by-product from various organic syntheses and petrochemical processes. Carbon oxysulfide is always formed when carbon, oxygen, and sulfur, or their compounds, such as carbon monoxide; carbon disulfide, and sulfur dioxide, are brought together at high temperatures. Hence, carbon, oxysulfide is formed as an impurity in various types of manufactured gases and as a by-product in the manufacture of carbon disulfide. Carbon oxysulfide is also often present in refinery gases.

Экологическая судьба

Toxicity from exposure to COS is likely the result of its decomposition to CO2 and H2S. H2S inhibits respiration at the cellular level, causing methemoglobinemia, which inhibits the cytochrome oxidase system, causing cytotoxic anoxia. In one study, rats treated with acetazolamide, an inhibitor of carbonic anhydrase, showed lower blood levels of H2S following exposure to COS and exhibited decreased toxicity. H2S is believed to be primarily responsible for many of the reported adverse effects associated with exposure to COS.
COS reacts readily with ammonia and primary amines to form ammonium thiocarbamate and amine salts of monothiocarbamic acid, respectively. Reaction with two primary amines may result in the formation of H2S and linking of the two amines via a carbonyl group reaction, suggesting considerable potential for protein cross-linking by COS in vivo, and this has been proposed as a mechanism to explain occupational neuropathy observed with CS2, and predicted for COS.

Перевозки

UN2204 Carbonyl sulfide, Hazard Class: 2.3; Labels: 2.3-Poisonous gas, 2.1-Flammable gas, Inhalation Hazard Zone C. It is a violation of transportation regulations to refill compressed gas cylinders without the express written permission of the owner. Cylinders must be transported in a secure upright position, in a well-ventilated truck. Protect cylinder and labels from physical damage. The owner of the compressed gas cylinder is the only entity allowed by federal law (49CFR) to transport and refill them. It is a violation of transportation regulations to refill compressed gas cylinders without the express written permission of the owner.

Методы очистки

Purify the gas by scrubbing it through three consecutive fritted washing flasks containing conc NaOH at 0o (to remove HCN), and then through conc H2SO4 (to remove CS2) followed by a mixture of NaN3 and NaOH solution; or passed through traps containing saturated aqueous lead acetate, then through a column of anhydrous CaSO4. Then it is freeze-pumped repeatedly and distilled through a trap packed with glass wool and cooled to -130o (using an n-pentane slurry). It liquefies at 0o/12.5mm. Use stainless steel containers. The gas is stored over conc H2SO4. [Glemser in Handbook of Preparative Inorganic Chemistry (Ed. Brauer) Academic Press Vol I p 654 1963.] TOXIC

Несовместимости

Carbon oxysulfide can form explosive mixture with air. Incompatible with strong bases. Incompatible with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions. Keep away from alkaline materials, strong bases, strong acids, oxoacids, epoxides.

Утилизация отходов

Return refillable compressed gas cylinders to supplier. Dissolve in a combustible solvent, such as alcohol, benzene, etc. Burn in a furnace with afterburner and scrubber to remove SO2 .