Tetrahydrofurane - water

Potassium hydride Air, chlorine, acetic acid, acrolein, acrylonitrile, maleic anhydride, nitroparaf-flns, A-nitrosomethylurea, tetrahydrofuran, water... 

The exocyclic C — C double bond in the chlorin can be reduced by catalytic hydrogenation in tetrahydrofuran/water in the presence of palladium(II) acetate with triethoxysilane as hydrogen source to yield under kinetic control cw-stereoisomers, which can be transformed by treatment with /)-toluenesulfonic acid in methanol to the thermodynamically favored trans-isomers.27d... 

Figure 4.29 An example of the use of ternary solvents to control mobile phase strength and selectivity in reversed-phase liquid chromatography. A, methanol-water (50 50) B, tetrahydrofuran-water (32 68) C, methanol-tetrahydrofuran-water (35 10 55). Peak identification 1 - benzyl alcohol 2 phenol 3 3-phenylpropanol 4 2,4-dimethylphenol 5 benzene and 6 -diethylphthalate. (Reproduced with permission from ref. 522. Copyright Elsevier Scientific Publishing Co.)...

Changing the organic component of the mobile phase can sometimes have a profound effect on selectivity. Fig. 3.1g shows a case where the order of elution is reversed when the mobile phase is changed from methanol/water 50 50 to tetrahydrofuran/water 25 75 ... 

The Group VI metal carbonyls demonstrate good activity in the WGSR, but differ significantly from ruthenium carbonyl in several ways. Tables IV and V summarize some WGSR experiments with chromium and tungsten carbonyls in a tetrahydrofuran-water solvent system. 

Retention volumes of monosubstituted benzenes, benzoic acid, phenols, and anilines have been measured in RPLC [76]. Buffered acetonitrile/water and tetrahydrofuran/water eluents were used with an octadecylsilica adsorbent. From the net retention volumes, a substituent interaction effect was calculated and described with the linear free energy relationship developed by Taft. The data was interpreted in terms of hydrogen bonding between the solutes and the eluent. 

Koizumi, E. and Miyamoto, H. The solubility of silver bromate in tetrahydrofuran-water mixed solvents. Bull. Chem. Soc. Jpn., 29(9) 950-953, 1956. 

Microextraction with decanoic acid, tetrahydrofuran, water... 

The reaction was carried out in aqueous acetone at room temperature using 0.2-1.0 mole % 0s04 (see Experimental section). b Solvent composition of 10 3 1 terf-butanol-tetrahydrofuran-water was preferred for this reaction. 

Testosterone enol diacetate reacts with perchloryl fluoride in aqueous dioxane to give 6a- and 6/i-fluorotestostcrone 17-acetatc (18 X = a-F, /i-F) as the major products along with 6a- and 6/3-hydroxytestosterone 17-acetate (18 X = a-OH, /j-OH) and also 17/i-hydroxyandrostane-3,6-dione 17-acctate.31 The enamine derivative 3-(pyrrolidin-l-yl)estra-3,5-dien-17/i-ol can be fluorinated in methanol at —25 to — 35 C to provide 4/J-fluoro-3a-methoxycstr-5-ene-3/f 17/ -diol (19),32 while various 2-fluoro-3-oxoestranc derivatives 20 are formed by fluorination of a number of 3-methoxyestrane derivatives in tetrahydrofuran/water mixture with perchloryl fluoride.33... 

The behavior of electrolytes in aqueous organic mixtures, particularly those consisting of dipolar aprotic solvents (1,2, S, 4,5,6) has long been a subject of considerable importance. Interest in dipolar aprotic solvent-water mixtures arises, in part, from the recent studies of tetrahydrofuran-water mixtures (7), which involved ion-solvation and proton bonding. Because of the scarcity of... 

Sometimes, mixture of solvents with water have been employed, probably with the aim of improving the phase transfer. These mixtures include ethanol/watcr,107 acetic acid/water.42-108 dioxane/water,109 diethyl ether/water, 10111 and tetrahydrofuran/water.46 Other solvent mixtures, e.g, ethanol/ dioxane,112 ethanol/diethyl ether, 3 diethyl ether. hexane,113 and dimethyl sulfoxidc/l-methyl-2-pyrrolidone,102 have been used in selected cases, with no given reason. 

An RP-HPLC procedure for the analysis of w-3 fatty acid esters that could eventually be adapted to the preparative isolation of quantities of EPA and DHA was also developed by Beebe et al. (48). The separations were performed at room temperature on an ODS-3 RAC II column (100 X 4.6-mm ID, 5-/zm particle size) with a guard column (30 X 4.6-mm ID dry-packed with SUPELCOSIL LC-18 40-yttm material). The esters were eluted with a mobile phase of acetonitrile/tetrahydrofuran/water (9 5 11) at a flow rate of 2.0 ml/min (detector differential refractometer). 

Methanol /tetrahydrofuran/water (67/27/6) Lycopene, /3-carotene Tomato grapefruit 35... 

This method of preparing alcohols is an adaptation of an oxymercuration procedure of Sand and Genssler2 and reduction methods of Henbest and Nicholls.3 Other methods for preparing 1-methylcyclohexanol are oxymercuration followed by reduction in tetrahydrofuran-water 4 reaction of cyclohexanone with... 

A two-phase mixture of methyl propiolate (5.0 g, 59.5 mmol), boric acid (5.5 g, 89 mmol), sodium benzenesulfinate (9.75 g, 59.5 mmol), and tetra-n-butylammonium hydrogen sulfate (3.0 g, 8.75 mmol) (Note 1) in tetrahydrofuran water (200 mL, 1 1) is stirred vigorously at room temperature for 48 hr (Note 2). The solution is acidified to pH 4 (2 N hydrochloric acid) and extracted into diethyl ether (4 x 50 mL) (Note 3). The organic layer is dried (MgSCU) and concentrated under reduced pressure to afford 13.75 g of yellow oil (Note 4) which is subjected to flash column chromatography (1.5 1 hexanes-diethyl ether) to afford initially methyl (E)-3-(benzenesulfonyl)prop-2-enoate (400 mg, 2.9%) and then the desired Z-isomer (10.89 g, 81%) as a pale yellow solid, pure by spectral study (Note 5). 

To examine whether the enzyme is active under the same conditions, we coated 0.1 mg each of nonhydroxy- and hydroxycerebrosides on 10 mg Celite (Analytical grade) and incubated it with 100 units of galactose oxidase for 60 min at room temperature. The result indicated that 5.6 nmol and 3.5 nmol each of nonhydroxy and hydroxycerebrosides (approximately 4.6 and 3.0% each were oxidized. Oxidation of the same cerebrosides by the same galactose oxidase in a tetrahydrofuran/water mixture as described by Radin (9) resulted in nearly complete oxidation. 

The preferential adsorption in dilute solution of poly(phenyl methacrylate) and its derivatives in tetrahydrofuran/water mixtures has been studied by differential refractometry and dialysis equilibrium [108], Relationships were found between the rigidity [Pg.32]

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