Aerosol cans, propellants

In the meantime, substitutes for halocarbons 11 and 12 are being sougjit. For their main uses either as aerosol-can propellants for consumer products, or as working fluids for heat exchangers in air-conditioning and refrigeration plant, the necessary properties are demanding. Apart from low cost and easily attainable... 

Use of propellants, e.g. hand-held aerosol cans Electrolytic processes... 

The same applies to the use of spray pistols (spray guns and aerosol cans), the frequency of whose use ought probably to be reduced on account of the propellant gas (chlorofluorohydrocarbons) employed Manual depression of the button valve of the vertically held spray can shoots the propellant gas through a fine jet and drags the sucked-up reagent solution with it onto the vertically held chromatogram (water pump pnnciple)... 

Aerosol cans which may contain a propellant together with products such as paints, cleaners, cosmetic preparations and foodstuffs. These may also contain some oxygen. 

Contained in engine-starting fluid purchased at automotive stores. To remove liquid ether from an engine-starting aerosol can, spray the contents of the can down a 12 inch ( 30cm) length of 3/4 inch PVC pipe. The ether will condense on the sides of the pipe and fall into the jar, while the inert propellant will be released into the air. Ether is extremely volatile. Ether floats to the top of the jar. 

A man habitually enjoyed the euphoric effects of inhaling whiffs of nitrous oxide in seclusion, and kept a cylinder of the gas in his sedan for that purpose. He decided to spray the faded car seats with an aerosol can of vinyl dressing (propanc/butanc propellant) with the windows closed. Then he had a whiff of gas from the briefly opened cylinder, and settled back to enjoy the euphoria and a cigarette. He was lucky to survive the resulting explosion of the fuel/oxidant mixture in a closed vessel [2],... 

Freons have been used as refrigerants, solvents, and propellants in aerosol cans. 

For aerosol products, the eye should be held open and the substance administered in a single, 1-s burst at a distance of about 4 inches directly in front of the eye. The velocity of the ejected material should not traumatize the eye. The dose should be approximated by weighing the aerosol can before and after each treatment. For other liquids propelled under pressure, such as substances delivered by pump sprays, an aliquot of 0.01 ml should be collected and instilled in the eye as for liquids. 

The following gases are or have been used in aerosol cans, some as propellants. Use the gases molecular formulas to calculate their molar masses. 

Carbon tetrachloride does not occur naturally but has been produced in large quantities to make refrigeration fluid and propellants for aerosol cans. Since many refrigerants and aerosol propellants have been found to affect the earth s ozone layer, the production of these chemicals is being phased out. Consequently, the manufacture and use of carbon tetrachloride will probably decline a great deal in the future. 

In 1974, F. Sherwood Rowland and Mario Molina, who shared the 1995 Nobel Prize in Chemistry with Crutzen, showed that chlorine from photolyzed chlorofluorocarbons (CFCs) such as CF2C12 and CFCI3, which were used as supposedly inert refrigerants, solvents for cleaning electronic components, plastic foam blowing agents, and aerosol spray propellants, can also catalyze ozone loss. Subsequently, the chlorine monoxide molecule CIO, which is involved in the chlorine-catalyzed ozone destruction cycle, has been shown to be present in the holes in the ozone layer and to correlate inversely with... 

Fill in aerosol cans with propellants such as propane and butane or with manual valves. 

Suspend PVP-lodine and Maize-P04-Aerosol (I) in the liquid mixture II and fill in aerosol cans with the propellants III. 

Sometimes the long-term effects are quite unexpected and difficult to predict. For example, millions of kilograms of CF2C12, which is used as a propellant, have been released into the atmosphere from aerosol cans. This compound appears to be wholly free of direct adverse physiological effects. However, as the substance diffuses into the upper atmosphere, it is slowly decomposed by sunlight to produce chlorine atoms. Serious danger then is possible because chlorine atoms are known to catalyze the decomposition of ozone, and it is the ozone layer in the upper atmosphere that absorbs most of the sun s ultraviolet radiation that is strongly harmful to life. 

In some patients, the propellant used in certain aerosols can cause acute bronchoconstriction (SEDA-6, 332). 

In 1985 large holes were discovered in the ozone layer over Antarctica, Australasia and Europe (Figure 7.12). Scientists think that these holes have partly been produced by chemicals called chlorofluorocarbons or CFCs. CFCs were developed as refrigerants in fridges back in the 1950s. They have also been used in air conditioning systems, in aerosol cans (as propellants) and in the manufacture of expanded plastics such as polystyrene. CFCs are very unreactive molecules. They escape into the atmosphere and, because of their inertness, remain without further reaction until they reach the... 

A group of compounds were discovered in the 1930s and were called the chlorofluorocarbons (CFCs). Because of their inertness they found many uses, especially as a propellant in aerosol cans. CFC-12 or dichlorodifluoromethane, CF2C12, was one of the most popular CFCs in use in aerosols. Scientists believe that CFCs released from aerosols are destroying the ozone layer and steps are being taken to reduce this threat. 

Nitrous oxide (laughing gas) is a colorless gas. It has a slightly sweet odor and taste and is somewhat soluble in water. It supports combustion of most substances almost as well as oxygen. Since the 1840 s the major use of nitrous oxide has been as an anesthetic - especially by dentists. It is also used as a propellant in some aerosol cans, in atomic absorption spectrophotometry, in cryosurgery and in racecar engines to provide extra power and acceleration. 

Users should also avoid inhaling directly from a nitrous oxide aerosol can. Some users have died as a consequence of freezing the throat area because the heat is absorbed as the gas expands. Freon, a similar molecule used as an aerosol propellant, does not have nitrous oxide effects. 

Small concentrations of ozone are found in the upper atmosphere where it is produced by sunlight in the ultraviolet region of the spectrum. Ozone absorbs ultraviolet light in the 200- to 360-nm (2000- to 3600-A) range, which provides protection from intense ultraviolet radiation at the earth s surface. Chlorofluorocarbons used as a propellant in aerosol cans and... 

Aerosols comprise compounds such as spray paints, hair sprays, pain-relieving sprays, deodorants, fabric-protector sprays, vegetable frying-pan lubricants, and hundreds of other everyday chemicals that are found in homes or are readily available commercially. Products that create an aerosol use propellants to keep tiny particles suspended in the air. For the most part these propellants, not the liquid product, are the chemicals abused. Virtually any aerosol product can be abused. 

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