Carbon monoxide cylinders

Table 8. Commercial Price and Purity Data for Cylinder Carbon Monoxide ...

Chemica.1 Properties. Reviews of carbonyl sulfide chemistry are available (18,23,24). Carbonyl sulfide is a stable compound and can be stored under pressure ia steel cylinders as compressed gas ia equiUbrium with Hquid. At ca 600°C carbonyl sulfide disproportionates to carbon dioxide and carbon disulfide at ca 900°C it dissociates to carbon monoxide and sulfur. It bums with a blue flame to carbon dioxide and sulfur dioxide. Carbonyl sulfide reacts... 

Hydrocarbons and carbon monoxide emissions can be minimised by lean air/fuel mixtures (Fig. 2), but lean air/fuel mixtures maximize NO emissions. Very lean mixtures (>20 air/fuel) result in reduced CO and NO, but in increased HC emissions owing to unstable combustion. The turning point is known as the lean limit. Improvements in lean-bum engines extend the lean limit. Rich mixtures, which contain excess fuel and insufficient air, produce high HC and CO concentrations in the exhaust. Very rich mixtures are typically used for small air-cooled engines, needed because of the cooling effect of the gasoline as it vaporizes in the cylinder, where CO exhaust concentrations are 4 to 5% or more. 

The mechanism of poisoning automobile exhaust catalysts has been identified (71). Upon combustion in the cylinder tetraethyllead (TEL) produces lead oxide which would accumulate in the combustion chamber except that ethylene dibromide [106-93-4] or other similar haUde compounds were added to the gasoline along with TEL to form volatile lead haUde compounds. Thus lead deposits in the cylinder and on the spark plugs are minimized. Volatile lead hahdes (bromides or chlorides) would then exit the combustion chamber, and such volatile compounds would diffuse to catalyst surfaces by the same mechanisms as do carbon monoxide compounds. When adsorbed on the precious metal catalyst site, lead haUde renders the catalytic site inactive. 

Precautions for handling carbon monoxide in compressed gas cylinders in addition to those given in Table 9.3 include ... 

Ixhe presence of Fe(CO)s in commercial cylinders of carbon monoxide at levels of 50 ppm has been reported (Chem, in Brit. 28, 517 (1992)). 

A cylinder of carbon monoxide equipped with a suitable regulator calibrated in pounds per square inch (p.s.i.g.) is connected to the three-way stopcock. All joints and the septum must be secured with clamps or wire. A vertical tube containing mercury was connected to an exit tube from the reaction flask by the checkers. A pressure of carbon monoxide was maintained against a 500-mm. column of mercury. 

Carbon monoxide is a stable gas. Metal carbonyls are relatively unstable and sensitive to light and moderately high temperatures. They may spontaneously ignite on contact with air. Volatile agents are stored in steel cylinders otherwise, agents are stored in steel or glass containers. Metal carbonyls may be stored under an inert gas blanket, such as nitrogen, to prevent contact with the air. 

Before we turn to "mechanisms" let us repeat how a catalyst works. We can reflux carboxylic acids and alcohols and nothing happens until we add traces of mineral acid that catalyse esterification. We can store ethene in cylinders for ages (until the cylinders have rusted away) without the formation of polyethylene, although the formation of the latter is exothermic by more than 80 kjoule/mol. We can heat methanol and carbon monoxide at 250 °C and 600 bar without acetic acid being formed. After we have added the catalyst the desired products are obtained at a high rate. 

To a 2 liter Hoke pressure cylinder are added 20.0 gm (0.21 mole) of aniline, 13.8 gm (0.43 mole) of sulfur, 100 ml of methanol, and 82 ml of an 8.75 M (0.73 mole) aqueous dimethylamine. The cylinder is pressurized with 100 psig of carbon monoxide, and then heated for 2 hr at 100°C. The cylinder is then vented and the contents removed from the cylinder by washing with hot methanol. The combined product and methanol washings were filtered hot and evaporated to dryness from the methanol. The urea product is recrystallized from 400 ml of water to give 27.8 gm (79%) of l,l-dimethyl-3-phenylurea, m.p. 130°-133°C. 

Both the products described here and the reaction intermediates are highly sensitive to oxygen, thus all the manipulations are carried out using inert atmosphere techniques4 with standard Schlenk ware. Oxygen-free carbon monoxide (purity 99.95%, 02 < 2 ppm) is from cylinders, and used without further purification. 

Nickel tetracarbonyl is a highly toxic volatile colorless liquid that is shipped in cylinders pressurized with carbon monoxide.8 Its vapor is about six times as dense as air. Purification of nickel by the Mond process is based on the decomposition of Ni(CO)4, the reverse of Eq. 15.3. The yellow-red iron pentacarbonyl slowly decomposes in air and is sensitive to light and heal. In feet. Fe-jfCOJy, an orange solid, is prepared by photolysis of Fe(CO). ... 

When the furnace is fully heated, boiling water is placed beneath the round-bottom flask and cold water passed through the condenser. Acetone is now dropped in at the rate of 3-4 cc. per minute. About half the acetone should be recovered as distillate in cylinder B (Note 5). Ketene, admixed with methane, carbon monoxide, and ethylene, passes into the reaction flasks (Note 6) in 25-20 per cent yields. The flow may be interrupted at will by checking the acetone flow. 

In reality, when octane burns in a restricted supply of air—such as in the cylinder of an automobile engine—some carbon monoxide is formed as well as carbon dioxide ... 

A schematic diagram of the apparatus used for preparing carbonyl fluoride from carbon monoxide and silver(II) fluoride is shown in Fig. 17. Cylinders of helium and carbon monoxide are connected through flowmeters and a pressure-release device to the copper reaction tube (47 in. long, 1-J in. diameter). A smaller copper vessel containing sodium fluoride pellets is connected with copper tubing and rubber fit-... 

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