Propane and the butanes

In the discussion appendix of the original paper by Carson and Katz (1942), Hammerschmidt indicated that, while the method was acceptable for gases of normal natural gas composition, an unacceptable deviation was obtained for a gas rich in ethane, propane, and the butanes. More work is also required to revise the Kvs -value charts for two components, namely, carbon dioxide and nitrogen. In three-phase hydrate data for binary mixtures of carbon dioxide and propane, Robinson and Mehta (1971) determined that the Kvs method for carbon dioxide gave unsatisfactory results. The API Data Book shows the Kvs values for nitrogen to be only a function of pressure, without regard for temperature Daubert (Personal... 

Propane has the formula C3H8 and butane C4H8. There are two isomers of butane, / -butane and isobutane (2-methylpropane). Propane and the butane isomers are gases at room temperature and atmospheric pressure like methane and ethane, all three are asphyxiants. A high concentration of propane affects the central nervous system. There are essentially no known systemic toxicological effects of the two butane isomers behavior similar to that of propane might be expected. 

The present study of the literature includes that relating to the paraffins of which propane and the butanes are the principal commercial products for manufacture of chemicals, to olefins of which ethylene and butadiene are most important, to alicyclics, to aromatics of which toluene, benzene, and the xylenes are of commercial interest, to acetylene, and to separation processes. 

The principal constituent of natural gas is methane (CH4). Other constituents are paraffinic hydrocarbons such as ethane (CH3CH3), propane, and the butanes. Many natural gases contain nitrogen (N2) as well as carbon dioxide (CO2) and hydrogen sulfide (H2S).Trace quantities of argon, hydro-... 

Thermal Polymerization. Although not as effective as catalytic polymerization, thermal polymerization has been used in many plants (about 40,000 b.p.d. during 1955) and especially as a means of utilizing the saturated gases that cannot be directly polymerized catalytically. The process consists essentially of vapor-phase cracking of propane and the butanes followed by prolonged time at 950 to 1100 F for polymeriza-... 

Several analyses are indicated in Table 20-19. The other type of catalyst, i.e., chromia-alumina, appears to be most useful for the dehydrogenation of propane and the butanes. Alumina prepared by calcining specially crystallized alumina trihydrate is used at 600 to 650 C for propane or isobutane. Chromium oxide in the form of its active gel is highly selective in its action but is destroyed by temperatures exceeding 500 C. If alumina is used as the carrier for 10 to 20 per cent chromium oxide, the dehydrogenation reaction proceeds at even 50 to 70 C but the life of the catalyst is short. Both the activated alumina and the alumina-chrome catalysts may be regenerated by careful oxidation of the impurities in a... 

Frey, F.E., Huppke, W.F., 1933. Equilibrium dehydrogenation of ethane, propane, and the butanes. Industrial Engineering Chemistry 25 (1), 54—59. 

Natural gas Hquids represent a significant source of feedstocks for the production of important chemical building blocks that form the basis for many commercial and iadustrial products. Ethyleae (qv) is produced by steam-crackiag the ethane and propane fractions obtained from natural gas, and the butane fraction can be catalyticaHy dehydrogenated to yield 1,3-butadiene, a compound used ia the preparatioa of many polymers (see Butadiene). The / -butane fractioa can also be used as a feedstock ia the manufacture of MTBE. 

In 1987 nonmotor fuel uses of butanes represented ca 16% of the total consumption. Liquid petroleum gas (LPG) is a mixture of butane and propane, typically in a ratio of 60 40 butane—propane however, the butane content can vary from 100 to 50% and less (see Liquefied petroleum gas). LPG is consumed as fuel in engines and in home, commercial, and industrial appHcations. Increasing amounts of LPG and butanes are used as feedstocks for substitute natural gas (SNG) plants (see Fuels, synthetic). / -Butane, propane, and isobutane are used alone or in mixture as hydrocarbon propellents in aerosols (qv). 

LPG (liquefied petroleum gas) Petroleum gas stored or proeessed as a liquid in equilibrium with vapour by refrigeration or pressurization. The two LPGs in general use are eommereial propane and eommereial butane supplied to produet speeifieations, e.g. BS 4250. (These, or mixtures thereof, eomprise LPG for the purpose of the Highly Flammable Liquids and Liquefied Petroleum Gas Regulations 1972.)... 

LPG is a mixture of flammable hydrocarbons which are gas at normal temperature hut liquid under pressure or when cooled below the boiling point at atmospheric pressure. Two mixtures are in common use, commercial propane and commercial butane. Large quantities are stored and handled at British Gas Corporation methane terminal, Shell UK Oil, Mobil Oil Co. Ltd, and Calor t ias LiJ The last also fills and handles large numbers of portable LPG cylinders. 

LPG in Mexico City consists of 50% by volume propane and 50% butane in the liquid phase, and of 80% and 20%, respectively, in the vapor phase. (Limited information is available on the actual LPG composition at the time of the accident.)... 

Commercial propane and butane often contain substantial proportions of the corresponding unsaturated analogues and smaller amounts of near-related hydrocarbons, as well as these hydrocarbons themselves. Figure 20.1 shows vapor pressure/temperature curves for commercial propane and commercial butane. Due to its lower boiling point, higher rates of vaporization for substantial periods are obtainable from propane than from butane, and at the same time, appreciable pressures are maintained even at low ambient temperatures. 

The propellant mixture present in the can was also detected in the headspace GC/MS analysis. These peaks eluted very early in the chromatogram and were not well separated. The propellant was a mixture primarily of propane and the isomers of butane and pentane. 

In addition to this skeletal isomerization reaction, Anderson and Avery (24) showed that in a suitable isotopically labeled hydrocarbon, a reaction leading to positional isomerization occurred. Thus, with n-butane-l-13C as the reactant, the isomerization products were 2-(methyl-13C) propane, and 7i-butane-2-13C ... 

Activation Energies and Frequency Factors for the Exchange of Propane and i-Butane... 

There are fewer UV absorbance studies of dinaphthylalkanes. Chandross and Dempster 9) have studied l,2-bis(l-naphthyl)ethane, l,3-bis(l-naphthyl)propane and l,4-bis(l-naphthyl)butane, as well as l,3-bis(2-naphthyl)propane and the compound l-(l-naphthyl)-3(2-naphthyl)propane. The latter had the same absorbance spectrum as a 50/50 mixture of 1- and 2-methylnaphthalene, while the bis compounds were shown to have the same absorbance spectrum as the corresponding methylnaphthalene isomer. These studies were made in a 90/10 v/v mixture of methylcyclohexane/isopen-... 

In alkane-alkene alkylation systems it is always the Jt-donor alkene that is alkylated by carbocations formed in the system. In the absence of excess alkenes (i.e., under superacidic conditions), however, the cr-donor alkanes themselves are alkylated. Even methane or ethane, when used in excess, are alkylated by ethylene to give propane and n-butane, respectively ... 

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