F Isopentane

Fig. 12.4. Vapor-to-water transfer data for saturated hydrocarbons as a function of accessible surface area, from [131]. Standard states are 1M ideal gas and solution phases. Linear alkanes (small dots) are labeled by the number of carbons. Cyclic compounds (large dots) are a = cyclooctane, b = cycloheptane, c = cyclopentane, d = cyclohexane, e = methylcyclopentane, f = methylcyclohexane, g = cA-l,2-dimethylcyclohexane. Branched compounds (circles) are h = isobutane, i = neopentane, j = isopentane, k = neohexane, 1 = isohexane, m = 3-methylpentane, n = 2,4-dimethylpentane, o = isooctane, p = 2,2,5-tri-metbylhexane. Adapted with permission from [74], Copyright 1994, American Chemical Society...

Slurry phase (or suspension) process. The uniquedooldng equipment in Figure 23—5 is a loop reactor. This process also takes place in a solvent (in this case, normal hexane, isobutane, or isopentane) so that the mixture can be pumped continuously in a loop while the polymerization is taking place. Feeds (the solvent, comonomer if any, ethylene and Ziegler-Natta catalyst) are pumped into the loop and circulated. Polymerization rakes place continuously at temperatures below the melting point of the polyethylene allowing solid polymer particles to form enough to form slurry. The reaction takes place at 185—212°F and 75—150 psi. A slurry of HOPE in hexane is drawn off continuously or intermittently. 

German for turpentine) and there are approximately 15000 terpenes. Terpenes are lipophilic, and the building blocks are five-carbon units with the branched carbon skeleton of isopentane. The basic units are sometimes called isoprene (F ig. 11.5fl), because heat decomposes terpenoids to isoprene. Depending on the number of C5 units fused, we distinguish mono- (Cio), sesqui- (C15), di- (C20), tri-(C30), tetra- (C40) and polyterpenoids [(Cs) , with n > 8]. Alpha-Pinene and bor-neol (Fig. 11.56) are examples of monoterpenes. 

Cold weather starting for ethanol fuels is poor unless blended with gasoline or some other starting fluid such as dimethyl ether or isopentane. The minimum starting temperature for neat ethanol fuel is about 60°F (15.6°F). In E95, E85, and E10 blends, the starting problems are minimized. 

Equilibria. The equilibrium distributions of butane, pentane, and hexane isomers have been experimentally determined (5, 16) and are diagrammed in Figure 2. In each case, lower temperatures favor the more highly branched structures. At the approximately 200° F. temperature usually employed for isomerization, the butane equilibrium mixture contains about 75% isobutane. That for pentane contains about 85% isopentane.. In the case of hexane, the equilibrium product contains about 50% neohexane and has a Motor octane rating of about 82. In all cases, of course, the yield of the desired isomers can be increased by fractionation and recycle. 

Amyl alcohols can be prepd either from fusel oil or by a synthetic method which involves hydrolysis of amyl chloride, which in turn is prepd by the chlorination of a mixt of pentane and isopentane obtained from petroleum. The ale prepd by synthetic method has, according to Ref 5,p 147, the following props d 0.812 to 0.820 20°/20°, boiling range 120 to 130°, n20° 1.409 and fl p(open cup) 113°F(45°)... 

A sealed container with volume of one cu ft holds 40 lbs of isopentane at 150°F. Calculate the volume of liquid in the container. 

Figure 13.23. Examples of vapor-liquid equilibria in presence of solvents, (a) Mixture of-octane and toluene in the presence of phenol, (b) Mixtures of chloroform and acetone in the presence of methylisobutylketone. The mole fraction of solvent is indicated, (c) Mixture of ethanol and water (a) without additive (b) with 10gCaCl2 in 100 mL of mix. (d) Mixture of acetone and methanol (a) in 2.3Af CaCl2 ip) salt-free, (e) Effect of solvent concentration on the activity coefficients and relative volatility of an equimolal mixture of acetone and water (Carlson and Stewart, in Weissbergers Technique of Organic Chemistry IV, Distillation, 1965). (f) Relative volatilities in the presence of acetonitrile. Compositions of hydrocarbons in liquid phase on solvent-free basis (1) 0.76 isopentane + 0.24 isoprene (2) 0.24 iC5 + 0.76 IP (3) 0.5 iC5 + 0.5 2-methylbutene-2 (4) 0.25-0.76 2MB2 + 0.75-0.24 IP [Ogorodnikov et al., Zh. Prikl. Kh. 34, 1096-1102 (1961)].

When a stream of oxygen containing 15% ozone was passed through a solution of isobutane in HSC F-SbFs-SOiClF solution held at —78°C, the colorless solution immediately turned brown in color. 1H and 13C NMR spectra of the resultant solution were consistent with the formation of the dimethylmethylcar-boxonium ion in 45% yield together with trace amounts of acetylium ion (CH3CO+). Further oxidation products (i.e., acetylium ion and C02) were reported to be observed in a number of reactions studied. Such secondary oxidation products, however, are not induced by ozone. Similar treatment of isopentane, 2,3-dimethylbutane, and 2,2,3-trimethylbutane resulted in formation of related carboxonium ions as the major products (Table 5.37). 

Liquid product was distilled batchwise for determination of liquid yields and product properties. In the batch distillation, the first liquid product cut was made at l80°F (true boiling point). Isopentane and n-pentane were added back to this distillation cut in the amount measured in the gaseous product. The resulting blend, mainly consisting of components with carbon numbers of 5 and 6, is referred to as "Cs-l80oF product."... 

With all of the catalysts in this study, the ratio of isopentane to normal pentane varies directly as the ratio of isohexanes to n-hexane. (In this paper, the branched C6 paraffins are collectively referred to as isohexanes.) Therefore, the iso/normal ratio of the paraffins of either carbon number can be correlated with octane number for C5-l80°F product of a given cycloparaffin content and serve as a convenient indication of catalyst performance. 

A solution of 2.8 mmol ofj-BuLi in cyclohexane/isopentane in 8 mL of F.t2Ois cooled to —78 °C and treated with 2.9 mmol of (-(-sparteine. After 10 min stirring a solution of 2.0 mmol of the spiro-carbamate 17 in 2 mL of Et20 is injected and the mixture is stirred for 5-6 h at —78 C. After addition of 3.5 mmol of trimethyltin chloride the reaction mixture is stirred for 16 li at —78 C. Workup is carried out as usual with 10 mL of Et2O/10 mL of 2 N HC1. and the crude product is purified by flash chromatography (silica gel. Et20/pentane mixtures). 

Fig. 5. Effect of hydrogen on pentane isomerization. Pentane feed containing 12% isopentane. Conditions temperature, 212°F. contact time, 3 hours AICI3, 11.5 wt.% and HCl, 3.2 wt.% based on pentane.

Fig. 6.30 F NMR spectra of a solution of PCUFj in isopentane at various temperatures. All of the fluorine resonances are doublets from 3ip-u>F coupling, (a) At -22 °C only a single doublet is observed, indicating that all of the fluorine atoms are equivalent, (b) At - 109 °C this resonance disappears, (c) At - 127 °C two new absorptions appear, (d) At - 143 °C two types of fluorine atoms arc seen a doublet of doublets at low field (two axial Fs) and a doublet of triplets at higher field (one equatorial F). [From Holmes, R. R. Carter, R. P., Jr. Peterson, G. E. Inorg. Chan. 1964, J. 1748-1754. Reproduced with permission.]...

Figure 2 The isopentane hydrogen-suppressed graph and the various types of subgraphs that can be obtained from the graph. Subgraphs are shown in bold lines with the remainder of the skeleton shown in dashed lines. Shown in light lines are two ring-type subgraphs (f = CH) and one cluster ( m = 4), which are not possible in the isopentane molecule.

---