Butane, isomers

Gas Recycle is a relatively simple operation. Rather than being circulated through a variety of pipes, pumps and columns, the catalyst remains in one place. A key control variable is maintaining a constant liquid level in the reactor. This is not as simple as it might first seem because in addition to butanal isomers forming, butanal condensation products including dimers and trimers also form to give what are collectively termed heavies . 

Catadiene [Catalytic butadiene] Also spelled Catadien. A version of the Houdry process for converting mixtures of butane isomers into butadiene by dehydrogenation over an alumina/chromia catalyst. Another version converts propane to propylene. Rapid coking of the catalyst necessitates use of several reactors in parallel, so that reactivation can be carried out continuously. Developed by Houdiy and first operated at El Segundo, CA, in 1944. By 1993, 20 plants had been built worldwide. Now licensed by ABB Lummus Crest. 

Like the butane isomers, the butylenes each have their own properties that rnake them unique and of individual appeal to the petrochemical industry. 

Raffinate-II typically consists of40 % 1-butene, 40 % 2-butene and 20 % butane isomers. [RhH(CO)(TPPTS)3] does not catalyze the hydroformylation of internal olefins, neither their isomerization to terminal alkenes. It follows, that in addition to the 20 % butane in the feed, the 2-butene content will not react either. Following separation of the aqueous catalyts phase and the organic phase of aldehydes, the latter is freed from dissolved 2-butene and butane with a counter flow of synthesis gas. The crude aldehyde mixture is fractionated to yield n-valeraldehyde (95 %) and isovaleraldehyde (5 %) which are then oxidized to valeric add. Esters of n-valeric acid are used as lubricants. Unreacted butenes (mostly 2-butene) are hydroformylated and hydrogenated in a high pressure cobalt-catalyzed process to a mixture of isomeric amyl alcohols, while the remaining unreactive components (mostly butane) are used for power generation. Production of valeraldehydes was 12.000 t in 1995 [8] and was expected to increase later. 

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 two butane isomers form an ideal solution in the liquid phase at the system temperature, the molecules being quite similar. Therefore, both activity coefficients can be taken to be unity. 

Other Uses. The form 5A is a traditional gas sohd chromatographic substrate for permanent gas analysis, the butane isomers, and cryogenic analyses of hydrogen isotopes. It is an additive to powders to improve flow properties and... 

Because there are two different butane isomers to begin with, each having two different kinds of H atoms, there are four possible alkyl groups containing four carbon atoms, each having a different name butyl, scc-butyl, isobutyl, and terf-butyl. 

This cost differential can be tolerated only in applications in which polymeric membranes completely fail in the separation [78]. Demanding separation applications, where zeolite membranes could be justified, due to the high temperatures involved or the added value of the components, and have been tested at laboratory scale, are the following separation of isomers (i.e., butane isomers, xylene isomers), organic vapor separations, carbon dioxide from methane, LNG (liquefied natural gas) removal, olefines/paraffins and H2 from mixtures. In most cases, the separation is based on selective diffusion, selective adsorption, pore-blocking effects, molecular sieving, or combinations thereof. The performance or efficiency of a membrane in a mixture is determined by two parameters the separation selectivity and the permeation flux through the membrane. 

So the name of this butane isomer is 2-methylpropane (propane with a methyl group joined to the second carbon atom of the chain instead of a hydrogen atom). Notice that the name has a dash between the number and the following letter. 

The first systematic phase equilibrium study of hydrates was carried out at the US Bureau of Mines by Deaton and Frost for a number of natural gas hydrate systems. Although the separation methods were somewhat crude (e.g., a distinction could not be made between butane isomers), their hydrate formation pressure and temperature data continue to be foundations for prediction comparisons. 

Table 5.4 The free energy function for the butane isomers...

Use the equations in Section 4.7 to predict the K-values of the two butane isomers and the four butene isomers at 220°F and 276.5 psia. Compare these values with the following experimental results [/. Chem. Eng. Data, 7, 331 (1962)]. 

Figure 1.10 Examples of the calculation of connectivity indices for butane isomers.

These two compounds have butane isomers in their name. Are they... 

Compared to propene, butenes show a lower solubility in water. Due to this the observed hydroformylation reaction rate of butene mixtures like raffinate-II (in general 40 % butene-1, 40 % butene-2, 20 % butane isomers) is significantly lower than that found for propene. However, a slight increase in the catalyst concentration is sufficient to achieve satisfying space-time yields for the pro-duction of valeric aldehydes. As a very selective catalyst the Rh/TPPTS- stem does not catalyze the hydroformylation of butene-2... 

The presence of a double bond usually increases the opportunities for isomerism. Thus, although there are only two butane isomers, there are four isomeric butenes. Isobutene is branched, and we might expect two n-butenes as shown ... 

The sample cell was loaded with 155.7 mg of Kureha carbon particles. Prior to the adsorption measurements the adsorbent particles were outgassed in situ in vacuum at 623 K for 16 h to remove any adsorbed impurities. The obtained dry sample weight was used in the calculation of isotherm data. Adsorption measurements were subsequently done at different temperatures from 194 to 338 K for ethane and ethene, from 273 to 358 K for propane and propene, and from 298 to 393 K for butane isomers. Five different temperatures for the adsorption of each adsorptive were used to reduce the uncertainty in the derived adsorption parameters. 

Like predicted for linear/branched mixture adsorption on silicalite-1 [4], for butane isomers over the whole pressure range the adsorption is favourable for the linear n-butane. This is attributed to the fact that energy and entropy as well as molecular sieving control the mixture adsorption of n-butane and isobutane on the activated carbon. 

Fuel gases Cigarette lighter refills Butane Propane n-butane iso-butane n-butane iso-butane Propane butane isomers... 

The minor is-o-butanal isomer R-CH-(CHO)-CH3 also forms. The aldehydes are intermediates of choice for the synthesis of alcohols (by hydrogenation), leading to detergents and plastifiers, and for the synthesis of carboxylic acids (by oxidation using Oi). For instance, propionic acid is synthesized from ethylene via propanal. 

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