Octane organic solvents

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). 

The liquid anion exchangers at present available are based largely on primary, secondary and tertiary aliphatic amines, e.g. the exchangers Amberlite LA.l [A/-dodecenyl(trialkylmethyl)amine] and Amberlite LA.2 [A/-lauryl(trialkyl-methyl)amine], both secondary amines. These anion exchange liquids are best employed as solutions (ca 2.5 to 12.5% v/v) in an inert organic solvent such as benzene, toluene, kerosene, petroleum ether, cyclohexane, octane, etc. 

As mentioned in the Introduction, in the discussion of liquid electrochemical cells it is necessary to distinguish two groups of immiscible liquid-liquid interfaces water-polar organic solvent, e.g., nitrobenzene, and water-nonpolar organic solvent (water-oil or water-hydrocarbon), e.g., octane type systems. It is schematically presented as... 

Almost no influence of the methylated /i-cyclodextrin on the yield can be observed if no additional organic solvent (except for butadiene or the product) is used as the non-polar phase. With hydroxypropyl-jd-cyclodextrin a decreased yield is obtained and the phase separation is more difficult. If cyclohexane or n-octane is added as the non-polar solvent the conversion and the yield increase with increasing cyclodextrin concentration up to a concentration of about 2 mol % cyclodextrin based on butadiene. Because of the high viscosity of the solution no further improvement can be achieved using higher cyclodextrin concentrations. Lower yields are obtained by use of a-cyclodextrin as compared with the methylated j8-cyclodextrin. 

The mean problem when measuring many aromatics and their halogenated derivatives is their hydrophobicity. For that reason it is desirable that these compounds be measured in non-polar organic solvents. It was demonstrated, that the response of a Rhodococcus globerulus (old name Corynebacterium MBl) containing biosensor to 2,3-dihydroxybiphenyl in decane or octane remained constant for up to 60 min [119]. The use of -hexane in a biosensor system based on Pseudomonas putida increased the sensitivity for phenol fivefold, the measurement frequency sixfold, and operational stabihty was 7 h [113]. 

Substantial variations of the organic solvent used in triphase catalysis with polystyrene-bound onium ions have been reported only for the reactions of 1-bromo-octane with iodide ion (Eq. (4))74) and with cyanide ion (Eq. (3)) 73). In both cases observed rate constants increased with increasing solvent polarity from decane to toluene to o-dichlorobenzene or chlorobenzene. Since the swelling of the catalysts increased in the same order, and the experiments were performed under conditions of partial intraparticle diffusional control, it is not possible to determine how the solvents affected intrinsic reactivity. 

Based on a suggestion by Odell and Earlam [119] that crown ethers and cryptands can cause proteins to dissolve in methanol, Broos and coworkers [120] investigated the effects of crown ethers on the enzymatic activity of a-chymotrypsin in the transesterification reaction of N-acetyl-L-phenylalanine ethyl ester with n-propanol in organic solvents. They observed a 30-fold rate acceleration when 18-crown-6 was used in octane. At that time, it was proposed that the water- and cation-complexing... 

Tocopherols and tocotrienols are pale yellow and viscous oils at high concentration. They are readily soluble in nonpolar organic solvents, e.g., hexane and octane. These solvents are usually used to extract tocopherols... 

This reaction is discussed in Section 5.2.3, p. 496, where the broad mechanism of the reaction and its preparative value is considered. The example included here is the preparation of 2-oxoundec-3-ene from octanal and diethyl 2-oxopropane-phosphonate,249 (Expt 5.211). The interest of the procedure is that the reaction is carried out under heterogeneous liquid-liquid conditions using a high concentration of potassium carbonate, but in the absence of an organic solvent and a phase transfer catalyst. This may be contrasted with the conditions which employ an aprotic solvent and a base such as sodium hydride (cf. Expt 5.17). 

In organic solvents, enzymes react at the same active site as in water covalent modification of the active center of the enzymes by a site-specific reagent renders them catalytically inactive in organic solvents (Zaks, 1988a). Upon replacement of water with octane as the reaction medium, the specificity of chymotrypsin towards competitive inhibitors reverses. 

Two reports demonstrate that Bronsted (Olah et al., 1999) or Lewis acids (Oakes et al., 1999) may be more reactive in sc C02 than in organic solvents. The isobutane-isobutylene alkylation (eq. 2.2), which is used commercially to increase the octane numbers in automotive fuels, has been demonstrated to occur in sc C02 with several liquid acid catalysts (Olah et al., 1999). Increased selectivity for Cg-alkylates is observed in sc C02 relative to neat acid media when anhydrous HF, pyridine poly(hydrogen fluoride) (PPHF),... 

The data in Table 5 would indicate that the reactivity in micelles is rather similar to that measure in organic solvents. Flowever, larger differences have been observed in some systems. l,4-Diazabicyclo[2.2.2]octane (DABCO) reactivity in micelles is considerably lower than in most organic solvents, a result explained in... 

Carbopalladation occurs with soft carbon nucleophiles. The PdCl2 complex of COD (100) is difficult to dissolve in organic solvents. However, when a heterogeneous mixture of the complex, malonate and Na2C03 in ether is stirred at room temperature, the new complex 101 is formed. This reaction is the first example of C—C bond formation and carbopalladation in the history of organopalladium chemistry. The double bond becomes electron deficient by the coordination of Pd(II), and attack of the carbon nucleophile becomes possible. The Pd-carbon n-bond in complex 101 is stabilized by coordination of the remaining alkene. The carbanion is generated by treatment of 101 with a base, and the cyclopropane 102 is formed by intramolecular nucleophilic attack. Overall, the cyclopropanation occurs by attack of the carbanion twice on the alkenic bond activated by Pd(II). The bicyclo[3.3.0]octane 103 was obtained by intermolecular attack of malonate on the complex 101 [11]. 

A great variety of chemical reactions can be advantageously carried out in microemulsions [860-862]. In one of the first papers in this field, Menger et al. described the imidazole-catalyzed hydrolysis of 4-nitrophenyl acetate in water/octane microemulsions with AOT as an anionic surfactant [=sodium bis(2-ethyl-l-hexyl)-sulfosuccinate] [864]. The solubilized water, containing the imidazole eatalyst, is confined in spherical pools encased by surfactant molecules, which have only their anionic head groups (-SOb ) immersed in the aqueous droplets. When the ester, dissolved in water-insoluble organic solvents, is added to this water/octane/AOT/imidazole system, it readily undergoes the catalysed hydrolysis under mild reaction conditions (25 °C). 

The coil-globule transition can also be observed by PL (from changes in the IMM of the polymer), when polymers are precipitated in organic solvents. These data were obtained for PMMA in toluene precipitated with octane or other non-solvents. Figure 9 shows the dependence Tw on the concentration of octane used as the precipitant for PMMA fractions of various molecular weights. Naturally, for PMMA in... 

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