Isopropanol coupling

Sanz MT, Gmehling J. 2006. Esterification of acetic acid with isopropanol coupled with pervaporation. Part I Kinetics and pervaporation studies. Chem. Eng. J. 123 1-8. 

Sanz M T and Gmehling J (2006b), Esterification of acetic add with isopropanol coupled with pervaporation. Part 11. Study of a pervaporation reactor , Chem g/, 123,9-14. 

Figure 9.4 Biocatalytic reduction of acetophenone and 3-butyn-2-one using lyophilized coli cells with overexpressed carbonyl reductase in neat substrates with isopropanol-coupled cofactor regeneration.

The extent of coupling is also influenced by the solvent. In the hydrogenation of aniline over ruthenium oxide, coupling decreased with solvent in the order methanol > ethanol > isopropanol > t-butanol. The rate was also lower in the lower alcohols, probably owing to the inhibiting effect of greater concentrations of ammonia (44). Carboxylic acid solvents increase the amount of coupling (42). 

This product probably arises from initial abstraction of a hydrogen radical from the isopropanol, followed by radical coupling ... 

Iridium-catalyzed transfer hydrogenation of aldehyde 73 in the presence of 1,1-dimethylallene promotes tert-prenylation [64] to form the secondary neopentyl alcohol 74. In this process, isopropanol serves as the hydrogen donor, and the isolated iridium complex prepared from [Ir(cod)Cl]2, allyl acetate, m-nitrobenzoic acid, and (S)-SEGPHOS is used as catalyst. Complete levels of catalyst-directed diastereoselectivity are observed. Exposure of neopentyl alcohol 74 to acetic anhydride followed by ozonolysis provides p-acetoxy aldehyde 75. Reductive coupling of aldehyde 75 with allyl acetate under transfer hydrogenation conditions results in the formation of homoallylic alcohol 76. As the stereochemistry of this addition is irrelevant, an achiral iridium complex derived from [Ir(cod)Cl]2, allyl acetate, m-nitrobenzoic acid, and BIPHEP was employed as catalyst (Scheme 5.9). 

The nylon or glass substrate on which the probe solution is deposited must be pretreated with coupling agents such as lysine or acrylamide functional groups. Coupling agents bind the probe cDNA to the substrate. After hybridization, the array is washed in heated isopropanol and water to remove any unhybridized sample DNA. It is essential... 

Reductive cross-dimerization has been established with ketones and 0-meth-oximes upon reduction in isopropanol with a Sn cathode as a convenient route to yS-amino alcohols, diastereoselectivities of up to 85 15 were obtained. A chiral ligand was obtained this way from the coupling of (-) - menthone with O-methyl acetaldoxime. Similarly, ketones could be coupled to hydrazones and nitrones. Also, intramolecular couplings were achieved with good yields and diastereoselectivity (Fig. 56) [308]. 

The use of water-miscible organic solvent-water mixtures is a particularly attractive method for use with cofactor-dependent enzymes due to its simphcity. The high water content can allow dissolution of both enzyme and cofactor, whilst the water-miscible solvent can provide a dual role in both substrate dissolution and as a cosubstrate for cofactor recycling (substrate-coupled cofactor recycling).The asymmetric reduction of a ketone intermediate of montelukast using an engineered ADH in the presence of 50 % v/v isopropanol offers a powerful demonstration of this methodology (Scheme 1.55). 

The recent introduction of non-aqueous media extends the applicability of CE. Different selectivity, enhanced efficiency, reduced analysis time, lower Joule heating, and better solubility or stability of some compounds in organic solvent than in water are the main reasons for the success of non-aqueous capillary electrophoresis (NACE). Several solvent properties must be considered in selecting the appropriate separation medium (see Chapter 2) dielectric constant, viscosity, dissociation constant, polarity, autoprotolysis constant, electrical conductivity, volatility, and solvation ability. Commonly used solvents in NACE separations include acetonitrile (ACN) short-chain alcohols such as methanol (MeOH), ethanol (EtOH), isopropanol (i-PrOH) amides [formamide (FA), N-methylformamide (NMF), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA)] and dimethylsulfoxide (DMSO). Since NACE—UV may present a lack of sensitivity due to the strong UV absorbance of some solvents at low wavelengths (e.g., formamides), the on-line coupling of NACE... 

Under the conditions of iridium-catalyzed transfer hydrogenation employing isopropanol as reductant, 1,3-cyclohexadiene couples to aryl aldehydes to provide... 

In collaboration with Jon Belisle, octanol pKa values were measured for a series of benzoic acids and phenols. A coupled electrode calibrated in aqueous buffers was used. The haIf-neutralization potential was measured since the Renderson-Hasselbalch equations would not apply. The titrant was 0.1 sodium hydroxide in isopropanol methanol 4 1. The titrant was only 6% of the total volume at half-neutralization, so the medium was essentially octanol-like. The results are listed in Table I and some benzoic acid values are plotted in Figure 6. 

Benzene hydrocarbons are known to undergo radical coupling reactions and the intramolecular reductive coupling of carbonyl compounds with a benzene ring has been achieved. Best conditions for this process are at a tin cathode with isopropanol solvent and tetaethylammonium tosylate as supporting electrolyte [102, 103], The reaction is performed at constant current in a divided cell. A single stereoiso-... 

Intermolecular coupling between ketones and 0-methyl oximes, hydrazones and nitrones is achieved on reduction at a tin cathode in isopropanol [105]. It is not clear which of the reacting species accepts the initial electron in these processes. The reaction with 0-methyloximes, followed by catalytic reduction of the first formed O-methylhydroxylamine, is a convenient synthetic route to 2-amino-alcohols. 

In the second approach the reducing equivalents are suppHed by a nicotinamide cofactor (NADH or NADPH) and for commercial viability it is necessary to regenerate the cofactor using a sacrificial reductant ]12]. This can be achieved in two ways substrate coupled or enzyme coupled (Scheme 6.2). Substrate-coupled regeneration involves the use of a second alcohol (e.g. isopropanol) that can be accommodated by the KRED in the oxidative mode. A problem with this approach is that it affords an equilibrium mixture of the two alcohols and two ketones. In order to obtain a high yield of the desired alcohol product a large excess of the sacrificial alcohol needs to be added and/or the ketone product (acetone) removed... 

HPLC methods can be ntilized for the pre-concentration of aromatic amines from polluted waters on silica gel or octadecyl silica (ODS) colnmns [55], The determination is then performed by RP HPLC using ODS packings as the stationary phases and a mixture of methanol, isopropanol, and water as the mobile phase [55], RP HPLC with diode array detector (DAD) methods coupled on-line with a continnons seqnential anaerobic/aerobic reactor system have been employed in wastewaters treatments [56], A continnons monitoring of the possible presence of aromatic amines in azo dyes wastes is based on indncing in the waste, the reaction of a reduction of the dye, followed by HPLC/ UV or HPLC/MS analysis [57-59], The redncing agent solutions are sodium dithionite or tin(II) chloride in an aqneons acidic medinm at 70°C, followed by SPE [58,59], LLE [60,61], or SEE [60-62],... 

Oxidative coupling of 2-bromo-4,6-di-im-butylphenol (202, Scheme 51) with potassium hexacyanoferrate(III) in a two-phase system consisting of aqueous potassium hydroxide and benzene affords the dibenzofuranone 203 by the mechanism indicated.The dibenzofuranone 203 is a convenient source of 1-dibenzofuranol (205). On boiling with isopropanol, compound 203 provides the tetra-tert-butyl-l-benzofuranol 204, which may be de-butylated by treatment with aluminum chloride in toluene. 1-Dibenzo-furanol (205) is also obtained by direct treatment of the dibenzofuranone 203 with aluminum chloride in toluene. With boiling methanol, however, compound 203 supplies the methoxy analog 206, which on mild debutylation affords 4-methoxy-1-dibenzofuranol (207). ... 

Fundamental studies by reflection angle infrared spectroscopy of the bonding of EME coupling agents to metal oxides reveal a significant shift in the carbonyl absorbance band when the coupling agent is applied as a very thin layer on a metal oxide. The shift is reproducible and the extent varies with the type of oxide. These results were obtained both by use of copper mirrors and from CuzO powder coated with very thin layers of model compounds. The compounds were not removable by isopropanol, a solvent for the bulk compound. The thiol absorbances of thin layers of model compounds were also found to decrease in relative intensity with time. This illustrates that a specific chemical interaction has occurred. 

Silane coupling agents. Monomeric and polymeric silane coupling agents were purchased from Petrarch Systems Co. (Bristol, PA) and used without further purification. Their chemical structures are given in Table 1. APS was obtained as the neat compound, and the polymeric silanes were supplied as 50% solution in isopropanol. The silanes were diluted to the required concentration in chosen solvents for application on fibers. 

Calvert et al. [12] studied the interfacial coupling of alkoxy titanium and zirconium tricarboxyls with metal oxides. They showed that isopropoxytitanium and zirconium tristearates interact with silica and alumina by exclusive loss of isopropanol, and that the titanate and zirconate were resistant to desorption by treatment with hot water. 

SPinto J.R. Fahy, JIndHygToxicol 24, 24-6(1942) CA 37,847(1943)(I etn TNT in air by collecting the sample in isopropanol by means of a midget impinger, reducing the TNT to triaminotoluene with TiCl, and estimating the triamino compd colorimetric ally after diazotization and coupling as described in the paper) 10)F. 

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