Liquid isobutane

Intermediate-mobility liquids Isobutane 294 5.0 Fuochi and Freeman (1972)... 

A coalescer works in the same way as a demister, except that it is used to accelerate the removal of droplets of a heavier liquid from a flowing lighter liquid. An ordinary coalescer is shown in Fig. 26.5. This coalescer was used to remove entrained caustic from a flowing isobutane stream. The liquid isobutane would impact the coalescer pad at a velocity of 1 to 2 ft/min. The droplets of caustic, which have a higher surface tension than isobutane, would adhere to the surface of the coalescer fibers. As the caustic droplets grew bigger and heavier, they would drain down the fibers of the pad, and into the boot. 

The work of the pump is given by Eq. (7.24), and the required value for the molar volume of saturated-liquid isobutane at 450 kPa (34 degC) is the value calculated in Problem 8.10 ... 

The normal boiling point of isobutane is -11.8°C. Estimate the fugacity of liquid isobutane this temperature and ISObar. 

The gases (mainly isobutane) leaving the top of cascade reactors are compressed, condensed, and then cooled by partial vaporization the resulting liquid isobutane (refrigerant) is recycled to the reactor. The dispersion leaving the reactor is separated by decanting. Most of the acid is then recycled to the reactor. 

The relatively high reactivity of the tertiary hydrogen in isobutane and the stability of the derivative -butyl hydroperoxide make isobutane an ideal but unusual substrate for studies of the oxidation of alkanes. Winkler and Heame [28] reported that the initiated oxidation of liquid isobutane at 125°C gave 75% f-BuOOH, 21% f-BuOH with small amounts of acetone and isobutyl derivatives. 

These results are at some variance with those of MacKay and Wolfgang (1962) who see no phase effect in acetylene yield and only a small effect on ethylene in comparing gaseous and liquid isobutane. They do, however, note that stabilization of the Cg build-up products may be going on since they observe an increase in both isopentane and 2-methyl-3-butene. The isopentane yield is probably enhanced because of stabilization of the methylene-insertion products. They also found a 25% decrease in acetylene from ethylene oxide on going from the gas to the solid which they ascribed to reaction of the intermediate with the cage. Ethylene in the gas, liquid, and solid phases was also studied. 

High atmospheric concentrations, e.g. in pooiiy ventilated spaces, can cause oxygen deficiency, with risk of unconsciousness. The measures on this card also apply to neopentane (2,2-dimethylpropane,CEHia). Use propane If ambient temperature drops below5°C. Under no circumstances warm cylinder. Turn leaking cylinder so that leak Is on top to prevent liquid Isobutane escaping. 

Liquid isobutane is oxidized to a mixture of r-butylhydroperoxide and t-butanol at about 120°C and 25-35 atm., with no catalyst present. A toluene solution of the hydroperoxide is then contacted with excess propylene gas at... 

Twenty minutes later, I was standing underneath an 8-inch line spewing a jet of liquid isobutane. I watched it flash to a white cloud in the warm Texas night. How had this happened What had caused a sudden leak to develop on the new carbon steel line ... 

Butane lighters contain about 5% n butane and 95% isobutane in a sealed con tamer The pressure pro duced by the two com pounds (about 3 atm) is enough to keep them in the liquid state until opening a small valve emits a fine stream of the vaporized mixture across a spark which ignites it... 

Butane-Naphtha Catalytic Liquid-Phase Oxidation. Direct Hquid-phase oxidation ofbutane and/or naphtha [8030-30-6] was once the most favored worldwide route to acetic acid because of the low cost of these hydrocarbons. Butane [106-97-8] in the presence of metallic ions, eg, cobalt, chromium, or manganese, undergoes simple air oxidation in acetic acid solvent (48). The peroxidic intermediates are decomposed by high temperature, by mechanical agitation, and by action of the metallic catalysts, to form acetic acid and a comparatively small suite of other compounds (49). Ethyl acetate and butanone are produced, and the process can be altered to provide larger quantities of these valuable materials. Ethanol is thought to be an important intermediate (50) acetone forms through a minor pathway from isobutane present in the hydrocarbon feed. Formic acid, propionic acid, and minor quantities of butyric acid are also formed. 

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). 

As discussed in Sec. 4, the icomplex function of temperature, pressure, and equilibrium vapor- and hquid-phase compositions. However, for mixtures of compounds of similar molecular structure and size, the K value depends mainly on temperature and pressure. For example, several major graphical ilight-hydrocarbon systems. The easiest to use are the DePriester charts [Chem. Eng. Prog. Symp. Ser 7, 49, 1 (1953)], which cover 12 hydrocarbons (methane, ethylene, ethane, propylene, propane, isobutane, isobutylene, /i-butane, isopentane, /1-pentane, /i-hexane, and /i-heptane). These charts are a simplification of the Kellogg charts [Liquid-Vapor Equilibiia in Mixtures of Light Hydrocarbons, MWK Equilibnum Con.stants, Polyco Data, (1950)] and include additional experimental data. The Kellogg charts, and hence the DePriester charts, are based primarily on the Benedict-Webb-Rubin equation of state [Chem. Eng. Prog., 47,419 (1951) 47, 449 (1951)], which can represent both the liquid and the vapor phases and can predict K values quite accurately when the equation constants are available for the components in question. 

At the Corpus Christi plant, liquid supplies of C4, C5, and Cg are delivered by truek and pipelines from nearby refineries. These liquids are proeessed through light end fraetionating units that remove the propane (C5 and Cg), and drop out isobutane and normal butane (whieh is reintrodueed into the stream for reproeessing.)... 

The liquid C4 is fed into the Olefiex unit where it is introdueed into a eold box for drying. It is then introdueed into a series of three heat exehangers, eombined with hydrogen and a eatalyst, and heated to 1,192°F (644°C). The proeess eonverts the isobutane to 48% isobutylene solution. 

To obtain light ends conversion, alkylation and polymerization are used to increase the relative amounts of liquid fuel products manufactured. Alkylation converts olefins, (propylene, butylenes, amylenes, etc.), into high octane gasoline by reacting them with isobutane. Polymerization involves reaction of propylene and/or butylenes to produce an unsamrated hydrocarbon mixture in the motor gasoline boiling range. 

Figure 4-13. Liquid-liquid heterogeneous tubular flow reaotor (e.g., alkylation of olefins and Isobutane). (Source J. M. Smith, Chemloal Engineering KInetlos, 3rd ed., McGraw-Hill, Inc., 1981.)...

Flowever, information concerning the characteristics of these systems under the conditions of a continuous process is still very limited. From a practical point of view, the concept of ionic liquid multiphasic catalysis can be applicable only if the resultant catalytic lifetimes and the elution losses of catalytic components into the organic or extractant layer containing products are within commercially acceptable ranges. To illustrate these points, two examples of applications mn on continuous pilot operation are described (i) biphasic dimerization of olefins catalyzed by nickel complexes in chloroaluminates, and (ii) biphasic alkylation of aromatic hydrocarbons with olefins and light olefin alkylation with isobutane, catalyzed by acidic chloroaluminates. 

The use of acidic chloroaluminates as alternative liquid acid catalysts for the allcy-lation of light olefins with isobutane, for the production of high octane number gasoline blending components, is also a challenge. This reaction has been performed in a continuous flow pilot plant operation at IFP [44] in a reactor vessel similar to that used for dimerization. The feed, a mixture of olefin and isobutane, is pumped continuously into the well stirred reactor containing the ionic liquid catalyst. In the case of ethene, which is less reactive than butene, [pyridinium]Cl/AlCl3 (1 2 molar ratio) ionic liquid proved to be the best candidate (Table 5.3-4). 

Like propane, butanes are obtained from natural gas liquids and from refinery gas streams. The C4 acyclic paraffin consists of two isomers n-butane and isobutane (2-methylpropane). The physical as well as the chemical properties of the two isomers are quite different due to structural differences, for example, the vapor pressure (Reid method) for n-butane is 52 Ib/in., while it is 71 Ib/in. for isobutane. This makes the former a more favorable gasoline additive to adjust its vapor pressure. However, this use is declining in the United States due to new regulations that reduce the volatility of gasolines to 9 psi, primarily by removing butane. ... 

Like propane, n-hutane is mainly obtained from natural gas liquids. It is also a hy-product from different refinery operations. Currently, the major use of n-hutane is to control the vapor pressure of product gasoline. Due to new regulations restricting the vapor pressure of gasolines, this use is expected to he substantially reduced. Surplus n-butane could be isomerized to isobutane, which is currently in high demand for producing isobutene. Isobutene is a precursor for methyl and ethyl tertiary butyl ethers, which are important octane number boosters. Another alternative outlet for surplus n-butane is its oxidation to maleic anhydride. Almost all new maleic anhydride processes are based on butane oxidation. 

Isobutane is used in cigarette lighters and camp stoves as a fuel. It is easily liquefied under pressure, and the liquid becomes a gas immediately when the pressure is released. It is also used as a propellant in hairsprays and spray breath fresheners. 

Refinery alkylation Liquid alkanes (e.g., isobutane) Gaseous alkenes (e.g., 1-butene) HF or H2SO4... 

Additional adsorption sites are provided on open metal sites, when available. [Cu3(BTC)2] is performant in the selective adsorption and separation of olefinic compounds. The highly relevant separations of propene from propane and of isobutene from isobutane have been accomplished with separation factors of 2.0 and 2.1, respectively [101, 102]. [Cu3(BTC)2] also selectively takes up pentene isomers from aliphatic solvent in liquid phase, and even discriminates between a series of cis- and trans-olefin isomer mixtures with varying chain length, always preferring a double bond in cis-position. This behavior is ascribed to tt -complexation with the open Cu sites [100]. 

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