Butane, molecular structure

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. 

Compounds having the same molecular formula but different molecular structures are called structural isomers. Butane and 2-methylpropane are referred to as structural isomers of C4H10. They are two distinct compounds with their own characteristic physical and chemical properties. 

Polyether-based foams account for more than 90% of all flexible polyurethane foams. The properties of foams are controlled by the molecular structure of the precursors and the reaction conditions. In general, density decreases as the amount of water increases, which increases the evolution of carbon dioxide. However, the level of water that can be used is limited by the highly exothermic nature of its reaction with isocyanate, which carries with it the risk of self-ignition of the foamed product. If very low density foams are desired, additional blowing agents, such as butane, are incorporated within the mixing head. 

The conversion of a chemical with a given molecular formula to another compound with the same molecular formula but a different molecular structure, such as from a straight-chain to a branched-chain hydrocarbon or an alicyclic to an aromatic hydrocarbon. Examples include the isomerization of ethylene oxide to acetaldehyde (both C2H40) and butane to isobutane (both C4H10). 

Maleic can be made by oxidation of butane or benzene. The process would otherwise be virtually impossible without the use of vanadium pen-toxide as the Catalyst. It enables extensive reconfiguration of either feedstoclcs molecular structure into the anhydride structure. 

The reduction of l,l-bis(diphenylphosphanyl) ethylene (248) with an excess of metallic lithium, activated by ultrasonic irradiation, leads to C—C coupling under the formation of a l,l,4,4-tetrakis(diphenylphosphanyl)butane (249) (Scheme 88)". Surprisingly, the lithium centres in the resulting dilithium compound do not form any lithium-carbon contacts, being coordinated by two diphenylphosphanyl groups and two TFIF molecules each. With this strucmral motif, the molecular structure is similar to the one of tris(phosphaneoxide) 20 (Section n. A), also obtained by Izod and coworkers upon deprotonation. ... 

The present chapter will primarily focus on oxidation reactions over supported vanadia catalysts because of the widespread applications of these interesting catalytic materials.5 6,22 24 Although this article is limited to well-defined supported vanadia catalysts, the supported vanadia catalysts are model catalyst systems that are also representative of other supported metal oxide catalysts employed in oxidation reactions (e.g., Mo, Cr, Re, etc.).25 26 The key chemical probe reaction to be employed in this chapter will be methanol oxidation to formaldehyde, but other oxidation reactions will also be discussed (methane oxidation to formaldehyde, propane oxidation to propylene, butane oxidation to maleic anhydride, CO oxidation to C02, S02 oxidation to S03 and the selective catalytic reduction of NOx with NH3 to N2 and H20). This chapter will combine the molecular structural and reactivity information of well-defined supported vanadia catalysts in order to develop the molecular structure-reactivity relationships for these oxidation catalysts. The molecular structure-reactivity relationships represent the molecular ingredients required for the molecular engineering of supported metal oxide catalysts. 

Compound 3a was found to react with excess water to produce a mixture of organic products including butane, ethene and ethane.17 However, when trace amounts of water were introduced into a hexane solution of 3b, the oxo complex 12 is formed. The molecular structure of 12 shows that it is formed by reaction of 2 equivalents of 3b and 1 equivalent of water ... 

H-transfer is always ca. 10 faster than 1 4 H-transfer at 600 °K (see Table 3), so it will predominate when the molecular structure of the fuel permits. Simple estimation of the relative concentrations of the hydroperoxyalkyl radicals derived from propane, n-butane and n-pentane illustrates this. Thus, if the relative frequency of attack by OH at primary, secondary and tertiary C—H bond is taken as 2 3 5 [102], then the relative concentrations of propyl, butyl and pentyl radicals may be obtained. The equilibrium constant for reaction (3)... 

The role of the molecular structure of the alcohol or the molecule considered. For instance, isomer butane diols on gold C2-C6 polyols on Pt and gold. ... 

O Reading Check Describe the difference in the molecular structures of butane and isobutane. 

Notice that both butanes have the same molecular formula, C4H10. These two possible butanes are structural isomers because they have the same molecular formulas, but they have different atom-to-atom bonding sequences. The straight-chain isomer is called a normal alkane and the other is a branched alkane (> Figure 1.12). 

Isobutane, C4H10, has the same molecular formula as butane, the straight-chain hydrocarbon. However, isobutane and butane have different structural formulas and, therefore, different molecular structures. Butane and isobutane are constitutional (or structural) isomers, compounds with the same molecular formula but different structural formulas. Figure 24.4 depicts molecular models of isobutane and butane. Because these isomers have different structures, they have different properties. For example, isobutane boils at - 12°C whereas butane boils at 0°C. Here the difference in boiling point can be attributed to the fact that isobutane has a more compact molecular structure than butane, which results in weaker intermolecular interactions between isobutane molecules. 

Notice that for alkanes with three or fewer carhon atoms, only one molecular structure is possible. However, in alkanes with more than three carbon atoms, the chains can he straight or branched. Thus, alkanes with four or more carhon atoms have structural isomers. There are two possible structural isomers for alkanes with four carhon atoms, butane and 2-methylpropane. 

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