Flammable gases alkenes

Butenes or butylenes are hydrocarbon alkenes that exist as four different isomers. Each isomer is a flammable gas at normal room temperature and one atmosphere pressure, but their boiling points indicate that butenes can be condensed at low ambient temperatures and/or increase pressure similar to propane and butane. The 2 designation in the names indicates the position of the double bond. The cis and trans labels indicate geometric isomerism. Geometric isomers are molecules that have similar atoms and bonds but different spatial arrangement of atoms. The structures indicate that three of the butenes are normal butenes, n-butenes, but that methylpropene is branched. Methylpropene is also called isobutene or isobutylene. Isobutenes are more reactive than n-butenes, and reaction mechanisms involving isobutenes differ from those of normal butenes. 

Propylene is a colorless, flammable gas that follows ethylene as the second simplest alkene hydrocarbon. It has an odor similar to garlic and has wide use in the chemical industry as an intermediate in the synthesis of other derivatives such as polypropylene, propylene oxide, isopropyl alcohol, acetone, and acrylonitrile. The production of propylene is similar to ethylene and is obtained through steam cracking of hydrocarbon feedstocks. Steam cracking is a process used to break molecules into smaller molecules by injecting the catalysts with steam. 

Ethylene - An alkene (unsaturated aliphatic hydrocarbon) with two carbon atoms, CH2=CH2. A colorless, highly flammable gas with a sweet odor. Autoignition point 543°C. Derived by thermal cracking of hydrocarbon gases or from gas synthesis. Used as monomer in polymer synthesis, refrigerants, and anesthetics. Also called ethene. 

Isobutylene (methylpropene) is a monounsaturated hydrocarbon with 4 carbon atoms. Under normal conditions it is a colourless, highly flammable gas (mixtures with air between 1.8 and 8.8 vol% at 20 °C can lead to explosions), and it has the characteristic alkene, petroleum-like scent. Isobutene is soluble in organic solvents (like ether, alcohol and hydrocarbons), but almost insoluble in water (0.263 g/L at 25°). It has no corrosive properties and has a low level of acute toxicity (still, extensive exposure should be avoided) (Industries E 2010 Liquide A 2013 Obenaus et al. 2000). 

A common colorless and flammable gas at room temperature and pressure, propene is generally produced from coal or petroleum and is a nonrenewable resource. However, it can be used in combination with hydrogen peroxide (H Oj) and employed as an inexpensive rocket fuel propellant. Alkenes can also form branched compounds, just as the alkanes (Figure 4.11). However, in the case of the alkene, the main part of the name is always the portion containing the double bond. And, it is important to identify the carbon atom from which the branch comes. Some examples of the names... 

Propylene, CjH (propene), has a boiling point of -53°F. The flammable range of propylene is 2 to 11%. The vapor density is 1.46, which is heavier than air. The four-digit UN identification number is 1077. The NFPA 704 designation is health 1, flammability 4, and reactivity 1. It is not toxic, but can be an asphyxiant gas by displacing the oxygen in the air. It is usually shipped as a pressurized liquid in cylinders, tank cars, and tank barges. The structure for propylene is shown in the Alkene section of this chapter. 

The simplest alkene is ethene, the compound which has previously been called ethylene . Ethene is produced in large quantities because it is one of the most important substances in the production of a wide variety of organic compounds and technological materials. The parent alkyne is ethyne which is marketed under the trade name of acetylene . This substance is also a very important industrial product. Both ethene and ethyne are flammable ethyne mixed with oxygen produces a very hot flame so acetylene is used for gas welding. Ethyne can be easily prepared from calcium carbide and water ... 

In academic labs, hydrogenation experiments are usually done on small quantities of reagents, usually less than 1 gram of an alkene or alkyne. In these situations, it is not necessary to worry about the inherent exothermicity of the reaction. However, on larger scale reactions, it is wise to consider how much heat will be liberated and if there are circumstances that might result in a reaction that could go out of control. Some of the catalysts used in hydrogenations are air-sensitive and should be added to a flask first under a blanket of nitrogen gas, before any flammable solvent is added. It is best to... 

The name of an alkene is derived from the corresponding alkane by changing the -ane ending to -ene. The alkenes have properties similar to alkanes-they are flammable and nonpolar. Their double bond, however, makes them susceptible to the addition of other atoms. A common reaction of alkenes is the addition of substituents across the double bond. For example, alkenes react with hydrogen gas to form alkanes. 

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