N-Butane system

Fig. 1. RPT compositions for an ethane-propane-n-butane system on 293-K water ( ) explosion (0) pop (O) boil.

Study of the particles formation and their growth from the demixion of the polystyrene-n-butane system by small pressure variations have demonstrated high efficiency of combined DLS and SLS measurements and allowed ... 

Testing of plates and other devices is carried out by Fractionation Research, Inc. for industrial sponsors. Some of the test data for sieve plates have been published for the cyclohexane/n-heptane and isobu-tane/n-butane systems. Representative data are shown in Fig. 14-43. These are taken from Sakata and Yanagi [Instn. Chem. Engrs. Symp. Ser. No. 56, 3.2/21 (1979)] and Yanagi and Sakata [Ind. Eng. Chem. Proc. Des. Devel., 21, 712 (1982)]. The column diameter was 1.2 m, tray spacing was 600 mm, and weir height was 50 mm. 

The phase diagram of the test methane + n-butane system is calculated. 

Sage, B.H., Hicks, B.L., Lacey, W.N. Phase equilibria in hydrocarbon systems. The methane-n-butane system in the two-phase region. Ind. Eng. Chem. 32, 1085 (1940)... 

Elliott, D.G., Chen, R.J.J., Chappelear, P.S., Kobayashi, R. Vapor-liquid equilibrium of methane-n-butane system at low temperatures and high pressures. J. Chem. Eng. Data 19, 71-77 (1974)... 

Beranek, P. Wichterle, I Vapour-liquid equilibria in the propane - n-butane system at high pressures Fluid Phase Equilib,... 

Rutherford, W.M. Calculation of Thermal Diffusion Factors for the Methane-n-Butane System in the Critical and Liquid Regions." AIChE J vol. 9, p. 841,1963,... 

Figures 8 and 9 illustrate the type of agreement that was obtained for the water content and the hydrocarbon distribution in both the hydrocarbon liquid and vapor phases for the methane n-butane-water system. It can be seen from Figure 8 that the predictions reproduce the water content very well at all temperatures. Figure 9 shows that the agreement between experimental and predicted hydrocarbon concentrations in the vapor and liquid phases is good at 100 F, although the agreements does not seem to be as good at 2220 F. The experimental data for 220 F may be open to question since the critical pressure for methane-n-butane mixtures at 220 F is reported to be about 1350 psia by Roberts et al (11). The experimental data of these authors on the methane-n-butane system at 220 F are Included for comparison. It seems doubtful that the presence of water in this system would increase the critical pressure to about 1550 psia as indicated by the three component data. In view of this, the predicted results are thought to be just as good at 220 F as at 100°F.

Figure 14,7 The phase envelope for the CO2 - n-butane system at 310.9 K (exp. data from Knapp et al, 1982, p.607).

Conformational free energy simulations are being widely used in modeling of complex molecular systems [1]. Recent examples of applications include study of torsions in n-butane [2] and peptide sidechains [3, 4], as well as aggregation of methane [5] and a helix bundle protein in water [6]. Calculating free energy differences between molecular states is valuable because they are observable thermodynamic quantities, related to equilibrium constants and... 

The lUPAC rules assign names to unbranched alkanes as shown m Table 2 2 Methane ethane propane and butane are retained for CH4 CH3CH3 CH3CH2CH3 and CH3CH2CH2CH3 respectively Thereafter the number of carbon atoms m the chain is specified by a Latin or Greek prefix preceding the suffix ane which identifies the com pound as a member of the alkane family Notice that the prefix n is not part of the lUPAC system The lUPAC name for CH3CH2CH2CH3 is butane not n butane... 

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. 

Figure 14.7 Typical clnomatogram obtained by using the refinery analyser system shown in Figure 14.6. Peak identification is as follows 1, hydrogen 2, Cg+, 3, propane 4, acetylene 5, propene 6, hydrogen sulfide 6, iso-butane 8, propadiene 9, n-butane, 10. iso-butene 11, 1-butene 12, traw-2-butene 13, cw-2-butene 14, 1,3-butadiene 15, iso-pentane 16, w-pen-tane 17, 1-pentene 18, tro 5-2-pentene 19, cw-2-pentene 20, 2-inethyl-2-butene 21, carbon dioxide 22, ethene 23, ethane 24, oxygen + argon, 25, niti Ogen, 26, carbon monoxide.

Other catalyst systems such as iron V2O5-P2O5 over silica alumina are used for the oxidation. In the Monsanto process (Figure 6-4), n-butane and air are fed to a multitube fixed-bed reactor, which is cooled with molten salt. The catalyst used is a proprietary modified vanadium oxide. The exit gas stream is cooled, and crude maleic anhydride is absorbed then recovered from the solvent in the stripper. Maleic anhydride is further purified using a proprietary solvent purification system. ... 

Fig. 12. Activity coefficients for the n-butane (I)-carbon dioxide (2) system.

The difference in behaviour between pentyl and butyl cation systems (Figs. 3 and 4) has also been encountered in trapping experiments with carbonium ions, primarily formed from alkanes and SbFs, by CO (Hogeveen and Roobeek, 1972). In the case of n-butane the secondary butyloxocarbonium ion is the main product, whereas in the case of n-pentane only the tertiary pentyloxocarbonium ion is found. 

We have previously in a number of papers [1-5] investigated these effects ft -both the Jahn-Teller inactive molecule n-butane [1] and the Jahn-Teller active molecules ethane, cyclopropane, and cyclohexane [2-5]. The choice of systems was largely dictated by the availability of experimental results [5-8]. New experiments being performed on selectively deuterated benzene have motivated a closer theoretical study of this system, and a first presentation of these investigations is given in the present paper. 

Other types of non-micro-channel, non-micro-flow micro reactors were used for catalyst development and testing [51, 52]. A computer-based micro-reactor system was described for investigating heterogeneously catalyzed gas-phase reactions [52]. The micro reactor is a Pyrex glass tube of 8 mm inner diameter and can be operated up to 500 °C and 1 bar. The reactor inner volume is 5-10 ml, the loop cycle is 0.9 ml, and the pump volume adds a further 9 ml. The reactor was used for isomerization of neopentane and n-pentane and the hydrogenolysis of isobutane, n-butane, propane, ethane, and methane at Pt with a catalyst. 

A further example is given by consideration of the preferred conformation of anti n-butane. This system is isoconjugate to trans 2,3-dimethyl-butadiene or trans 2,3-divinylbutadiene. Now, trans 2,3-dimethyl-butadiene is expected to have the conformation shown below. 

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