Isooctane as solvent

The alkylation of 2,4-di-tert-butylphenol with cinnamyl alcohol was carried out in a 25 ml flask with 0.25 mmol 2,4-di-tert-butylphenol (Aldrich) and 0.25 mmol cinnamyl alcohol (Aldrich) using 12.5 ml isooctane as solvent. When the solution was heated and maintained at 60°C, 125 mg catalyst was added. After 6 h s reaction, the catalyst was filtered and extracted with dichloromethane to recover adsorbed reaction products. 1,3 -Di-tert-butylbenzene was used as internal standard and the products were analyzed by GC (HP5890) and GC-MS (HP5890). 

Satchell and Satchell" reported a kinetic study on the aminolysis of p-nitrophenyl isothiocyanate with primary amines and anilines in diethyl ether and isooctane as solvents. The detailed analysis reveals that the aminolysis occurs via a zwitterionic intermediate, T , which undergoes subsequent proton transfer catalyzed by a second amine molecule (equation 12). Added carboxylic acids form inactive 1 2 amine-acid complexes with strong basic amines and inhibit aminolysis, but with weak bases the acids form only a negligible amount of complex and they catalyze the aminolysis. 

This reaction is more than two orders of magnitude faster in water than when using isooctane as solvent [4], Jorgensen rationalized this effect by the coordination of two water molecules to the oxygen atom of the carbonyl group (Fig. 1, left) [5,6]. 

Naproxen, (S)-2-(6-methoxy-2-naphthyl)propanoic acid 126 is a nonsteroidal anti-inflammatory and analgesic agent first developed by Syntex [220,221]. Biologically active desired S-naproxen has been prepared by enantioselective hydrolysis of the methyl ester of naproxen by esterase derived from Bacillus subtilis Thai 1-8 [222]. The esterase was subsequently clone in Escherichia coli with over 800-fold ipcrease in activity of enzyme. The resolution of racemic naproxen amide and ketoprofen amides has been demonstrated by amidases from Rhodococcus erythropolis MP50 and Rhodococcus sp. C311 (223-226). 5-Naproxen 126 and 5-ketoprofen 127 (Fig. 44) were obtained in 40% yields (theoretical maximum yield is 50%) and 97% e.e. Recently, the enantioselective esterification of naproxen has been demonstrated using lipase from Candida cylindraceae in isooctane as solvent and trimethylsilyl as alcohol. The undesired isomer of naproxen was esterified leaving desired S isomer unreacted [227]. 

In this technique sediment or sludge is suspended in water, which is refluxed for 3-5 h, while the distillate is percolated through a small amount of extraction solvent (1—5 mL), which is in most cases cyclohexane [2,31-34]. Jobst [35] used isooctane as the extraction solvent. 

Ultraviolet absorption spectra of thiophene derivatives were recorded using isooctane as a solvent (8). An apparent hypsochromic effect caused by the second nitro group in 2,5-dichloro-3,4-dinitro-thiophene was noticed. 

Peroxide in solution is necessary to produce fast co-oxidation. When isooctane was used as solvent instead of benzene, a slow and linear oxygen uptake was observed (0.5 mole per mole of indene in 100 hours at 20°C.). This behavior was the result of low solubility in the paraffin of the hydroperoxide, I, which precipitated out and rapidly rearranged to inactive sulfoxides. 

Inclusion of the different ketones in Silicalite was achieved as described previously (14,15), using 2,2,4-trimethylpentane (isooctane) as a solvent for the ketones. In our study of substituent effects we have used 120 mg of ketone per gram of Silicalite in all inclusion attempts. The quantities used would yield samples in which up to 60% of the void volume of Silicalite (0.19 mL/g) could be occupied. The actual yields (and therefore the efficiency of inclusion) were determined by microanalysis, and the results are listed in Table I. 

The first practical example of an on-line SFC-1 NMR separation was recorded by Dorn and co-workers [16] (Figure 7.2.14). Since up to 90% of a fuel is aliphatic, SFC-NMR on-line analysis is the matter of choice for separation and identification. Figure 7.2.14 shows a fuel mixture of isooctane, n-hexane, -nonane, dodecane, and n-hexadecane, separated by SFC and detected by on-line NMR spectroscopy. The SFC separation was accomplished with a flow rate of 2.0ml/min, a C18 250 x 4.6 mm column, operated at an isobaric pressure of 100 bar and a temperature of 323 K, using CO2 with 1% (w/w) CD3CN as solvent. Each NMR spectrum consists of 20 co-added transients at an acquisition time of 1 s per transient. The total separation occurred within 5 min. The first eluting isooctane can be easily identified by the methylene-to-... 

For example, the rate of the Diels-Alder cycloaddition reaction between 9-(hydroxymethyl)anthracene and A-ethylmaleimide, as shown in Eq. (5-159), is only slightly altered on changing the solvent from dipolar acetonitrile to nonpolar isooctane, as expected for an isopolar transition state reaction cf. Section 5.3.3. In water, however. 

Most Sharpless asymmetric epoxidations have been conducted in dichloromethane since this solvent was that initially employed. Other solvents that have been successfully used are toluene, heptane and isooctane. Due to the stability in storage of terf-butyl hydroperoxide in isooctane this solvent is now recommended, with dichloromethane and toluene as the next choices42. 

M. Harrod and 1. Elfman Enzymatic synthesis of phosphatidylcholine with fatty acid, isooctane, carbon dioxide, and propane as solvents. Journal of the American Oil Chemists Society 72 (1995) 641-646. 

The second example is the telomerization of phthalic acid with butadiene yielding bis(octadienyl) phthalates, which can be used as plastic softeners after hydrogenation. The polar solvent dimethyl sulfoxide contains the palladium catalyst formed from Pd(acac)2 and tris(p-methoxyphenyl)phosphite. This extraction uses isooctane as well [34]. 

In 1980, Breslow (3) made the dramatic observation that the reaction of cyclopentadiene with butenone in water was more than 700 times faster than the same reaction in isooctane. The reaction rate in methanol is comparable to that in a hydrocarbon solvent. Such an unusual acceleration of the Diels-Alder reaction by water was attributed to the "hydrophobic effect (4) in which the hydrophobic interactions brought together the two nonpolar groups in the transition state. The use of P-cyclodextrin, which simultaneously forms an inclusion complex with the dioie and dienophile, and the use of 4.86 M LiCl aqueous solution as solvent, which salts out nonpolar materials dissolved in water (5), further enhanced the rate of aqueous Diels-Alder reactions. The second-order rate constant of the reaction between hydroxymethylanthiaceneandN-ethylmaleimideinwaterat 45°C was over 200 times larger than in acetonitrile (eq. 1). 

The partitioning behavior of the epoxide (substrate) and the diol (product) between the two phases was first investigated. As a result, both the epoxide and the diol were mostly dissolved in the organic phase when chloroform, dodecanol, or /r-decane was used. Moreover, dodecanol and n-decane easily formed emulsions with the buffer (potassium phosphate or KPB), which were difficult to separate. When using n-hexane, n-octane, or isooctane as the organic solvent, the epoxide partitioned mainly in the organic phase while the diol dissolved mainly in the aqueous phase. The partition difference... 

A new reverse microemulsion technique currently in focus, i.e. that with supercritical fluids as oil phase has been used by Cason and Roberts [228] to synthesize Cu nanoparticles. These authors used supercritical ethane along with isooctane co-solvent (255 bar, 37°C) to obtain particles by reactions involving NaAOT, Cu(AOT)2 and hydrazine. In addition, compressed liquid propane and isooctane were also used separately as the continuous phase (145 bar, 30°C). The particles had an approximate size range of 15-20 nm. 

This value obtains when the solvent used is a hydrocarbon (such as isooctane). Other solvents (e.g., ehloroform and water) apparently eause a further bathochromic shift. The role of solvents, in general, will be discussed subsequently in this ehapter. 

AOT RMs form in aromatic (benzene, toluene, chlorobenzene, xylene) and aliphatic (n-heptane, n-hexane, isooctane, decane) solvents. BHDC forms RMs in aromatic or mixture of aromatic-aliphatic solvents [27-34]. TX-lOO, one of the most commonly used nonionic surfactants used to prepare RMs, is able to form this kind of organized system in various hydrocarbon solvents [18-23, 35]. All three surfactants—AOT, BHDC, and TX-lOO—form RMs without the addition of a cosurfactant. The maj ority of studies on RMs, solubilize water as the polar component and juxtapose properties such as polarity, viscosity, conductivity and H-bonding for bulk water and confined in RMs [36, 37]. These studies show that the physicochemical... 

The DAR between A-ethylmaleimide and 2,3-dimethyl-l,3-butadiene was studied in microemulsions with IL [52], The apparent second-order rate constants were determined by spectrophotometry in the IL microemulsion and AOT microemulsion (Fig. 18.12). They increased with both water content (molar ratio of IL aqueous solution to surfactant) and surfactant concentration (Caq.j,) in the IL microemulsion systems. The effect of various solvents on the DAR rate was investigated, and results were shown that the rate constants in both AOT microemulsion and IL microemulsion were roughly four to five times higher than that in the isooctane and the in pure IL were at least 10 times higher than that in the isooctane as shown in Figure 18.13. The results indicated that high temperature accelerated the reaction and the apparent activation energy, E, decreased with the increase of the water content (molar ratio of IL aqueous solution to surfactant). 

In terms of the conversion yield, this procedure using Novozyme 435 is superior to the previously reported procedure affording CAPE with the maximum conversion yield of 50% (Kishimoto et al., 2005a). CAPE was obtained by transesteiification catalyzed by Novozyme 435 using isooctane as the solvent with the conversion yield of 91.65% (Chen et aL, 2010). The conversion yields of the CAPE analogues produced by the [bnTtm][NTf2] system are comparable to that of CAPE produced by the isooctane system. 

In liquid-solid adsorption chromatography (LSC) the column packing also serves as the stationary phase. In Tswett s original work the stationary phase was finely divided CaCOa, but modern columns employ porous 3-10-)J,m particles of silica or alumina. Since the stationary phase is polar, the mobile phase is usually a nonpolar or moderately polar solvent. Typical mobile phases include hexane, isooctane, and methylene chloride. The usual order of elution, from shorter to longer retention times, is... 

Sodium acetate reacts with carbon dioxide in aqueous solution to produce acetic anhydride and sodium bicarbonate (49). Under suitable conditions, the sodium bicarbonate precipitates and can be removed by centrifugal separation. Presumably, the cold water solution can be extracted with an organic solvent, eg, chloroform or ethyl acetate, to furnish acetic anhydride. The half-life of aqueous acetic anhydride at 19°C is said to be no more than 1 h (2) and some other data suggests a 6 min half-life at 20°C (50). The free energy of acetic anhydride hydrolysis is given as —65.7 kJ/mol (—15.7 kcal/mol) (51) in water. In wet chloroform, an extractant for anhydride, the free energy of hydrolysis is strangely much lower, —50.0 kJ/mol (—12.0 kcal/mol) (51). Half-life of anhydride in moist chloroform maybe as much as 120 min. Ethyl acetate, chloroform, isooctane, and / -octane may have promise for extraction of acetic anhydride. Benzene extracts acetic anhydride from acetic acid—water solutions (52). 

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