Hydrocarbons n-butane

A number of other chemicals have been converted to MA. There is no account of any of them being utilized commercially thus far. Among these are furfural, " mixed olefins, cyclopentadiene, toluene, " ter-penes, etc. So far, these have been of academic interest due to unfavorable economics and/or low selectivity to MA. Raw material supply and demand pictures are known to change rapidly and particularly so in the recent past. For the present, however, given the present economics and state-of-the-art technology, benzene and C4 hydrocarbons (n-butane in the United States) are the choice of feedstocks. In addition, there is by-product MA produced during phthalic anhydride manufacture. 

Starting with the simple hydrocarbon, n-butane, we have seen that more than 65 different oxygenates are expected to be formed as its atmospheric oxidation proceeds. The atmospheric oxidation of the larger hydrocarbons leads to very much higher numbers of different oxygenates. The complex array of oxygenates that has been identified in the atmosphere represents only a small fraction of the actual number that are expected to be formed. It is clear that the atmospheric oxidation of the hydrocarbons is a major source of a vast array of oxygenates that have been found or are expected to be formed in the troposphere. 

Figure B-21. N-butane pressure-enthalpy diagram. (From Edmister and Lee. Applied Hydrocarbon Thermodynamics. VdI I, Second Edition, Gulf Publishing Company, Houston, TX, 1984.)...

Separation of individual saturated hydrocarbons from the petroleum fractions and subsequent conversion to more useful products. Important examples are n-butane to butadiene and cyclohexane to nylon intermediates. 

Evaporative emissions from vehicle fuel systems have been found to be a complex mixture of aliphatic, olefinic, and aromatic hydrocarbons [20,24,33]. However, the fuel vapor has been shown to consist primarily of five light paraffins with normal boiling points below 50 °C propane, isobutane, n-butane, isopentane, and n-pentane [33]. These five hydrocarbons represent the more volatile components of gasoline, and they constitute from 70 to 80 per cent mass of the total fuel vapor [24,33]. 

Once the heel has been established in the carbon bed, the adsorption of the fuel vapor is characterized by the adsorption of the dominant light hydrocarbons composing the majority of the hydrocarbon stream. Thus it is common in the study of evaporative emission adsorption to assume that the fuel vapor behaves as if it were a single light aliphatic hydrocarbon component. The predominant light hydrocarbon found in evaporative emission streams is n-butane [20,33]. Representative isotherms for the adsorption of n-butane on activated carbon pellets, at two different temperatures, are shown in Fig. 8. The pressure range covered in the Fig. 8, zero to 101 kPa, is representative of the partial pressures encountered in vehicle fuel vapor systems, which operate in the ambient pressure range. 

Paraffinic Hydrocarbons Methane Ethane Propane n-Butane 1-Butane n-Pentane n-Hexane... 

Light naphtha containing hydrocarbons in the C5-C7 range is the preferred feedstock in Europe for producing acetic acid by oxidation. Similar to the catalytic oxidation of n-butane, the oxidation of light naphtha is performed at approximately the same temperature and pressure ranges (170-200°C and =50 atmospheres) in the presence of manganese acetate catalyst. The yield of acetic acid is approximately 40 wt%. 

Butadiene is mainly obtained as a byproduct from the steam cracking of hydrocarbons and from catalytic cracking. These two sources account for over 90% of butadiene demand. The remainder comes from dehydrogenation of n-butane or n-butene streams (Chapter 3). The 1998 U.S. production of butadiene was approximately 4 billion pounds, and it was the 36th highest-volume chemical. Worldwide butadiene capacity was nearly 20 billion pounds. 

Gasoline contains more than 250 components of a mixture of C4-C12 hydrocarbons, which varies in concentration from batch to batch. Some of these components are isobutane, n-butane. isopentane, n-pentane, 2,3-dimethylbutane, 3-methylpentane, n-hexane, 2,4-dimethylpentane, benzene, 2-methylhexane, 3-meth-ylhexane, 2,2,4-trimethylpentane, 2,3,4-trimethylpentane, 2,5-dimethylhexane, 2,4-dimethylhexane, toluene, 2,3-dimethylhexane. ethylbenzene, methylethylbenzenes, m-, p-, and o-xylene, trimeth- ylbenzenes, naphthalene, methylnaphthalenes, and dimethylnaph-thalenes... 

Butadiene has the advantage of a relatively low heat of reaction (995 kJ/ mol compared with 1875 kJ/mol in the oxidation of benzene), but the disadvantage of a relatively high price compared with the other -C4 hydrocarbons. Good prospects has the n-butane route. Keeping the n-butane conversion at about 15%, the yield of maleic acid anhydride amounts to 50-60 mol %. 

The paraffin hydrocarbon containing four carbon atoms is called butane, but two 4-carbon (C4) paraffins are possible. The butane with its carbons in a line is known as normal butane or n-butane. The branched chain butane is isobutane or i-butane. Although each compound has the formula C4H10, they have different properties for example, n-butane boils at -0.5°C while isobutane boils at -11.7°C. n-Butane and i-butane are isomers of each other. The straight-chain paraffin is always called the normal form. 

As one more common example of liquid fuels present reference may be drawn to liquified petroleum gas (LPG) or bottled gas or refinery gas. This fuel is obtained as a by-product during the cracking of heavy oils or from natural gas. It is dehydrated, desulfurized and traces of odours organic sulfides (mercaptans) are added in order to identify whether a gas leak has occurred. Supply of LPG is carried out under pressure in containers under different trade names. It consists of hydrocarbons of great volatility such that they can occur in the gaseous state under atmospheric pressure, but are readily liquifiable under high pressures. The principal constituents of LPG are n-butane, iso-butane, butylene and propane,... 

At a pressure of 10 bar, determine the bubble and dew point of a mixture of hydrocarbons, composition, mol per cent n-butane 21, n-pentane 48, n-hexane 31. The equilibrium K factors can be estimated using the De Priester charts in Chapter 8. 

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 ... 

Exothermic Reactions of Transition Metal Ions with Hydrocarbons. Cross sections for the formation of product ions resulting from the interaction of Ni+ with n-butane are shown in Figure 6 for a range of relative kinetic energies between 0.2 and 4 eV. In contrast to the results shown in Figure 3, several products (reactions 6-8) are formed with large cross section at low energies. These cross sections decrease with... 

Figure 4a Summary of the reactions of rhenium atoms with acyclic saturated hydrocarbons. Rhenium atoms were co-condensed with the indicated substrates at -196 °C. (i) Ethane (ii) Propane (iii) n-Butane (iv) Neopentane (v) 2-Methylpropane and (vi) Tetramethylsilane.

Schubert, C.C., Pease, R.N. (1956) The oxidation of lower paraffin hydrocarbons. I. Room temperature reaction of methane, propane, n-butane and isobutane with ozonized oxygen. J. Am. Chem. Soc. 78, 2044—2048. 

The main conclusion of this study is that hydrocarbon-based surface geochemical methods can discriminate between productive and non-productive oil and gas reservoir areas. Variables in surface soils that best distinguish productive and non-productive areas are ethane and n-butane and heavy (C24+) aromatic hydrocarbons. Heavy metals (U, Mo, Cd, Hg, Pb) are possibly indirect indicators of hydrocarbon microseepage, but they are more difficult to link with the reservoirs. 

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