Homogeneous toluene

Fig. 24 SEM cross sections of cMorobenzene (a, b) and toluene (c, d) based MDMO-PPV PCBM blends. Whereas chlorobenzene based blends are rather homogeneous, toluene cast blends reveal large PCBM clusters embedded in a polymer-rich matrix or skin layer. Small features—referred to as nanospheres —are visible in all cases and can be attributed to the polymer in a coiled conformation. The blending ratio is depicted in the lower right corner. (Reproduced from [55] with permission, 2004, Wiley-VCH)...

An intriguing pattern formation involving the pinning due to vitrification was observed for the films of PS/PB, PS/SB, and PS/PB/SB prepared by evaporating homogeneous toluene solutions containing about 5 wt% polymers in total. The mixtures studied have an unequal fraction of each polymer. Figure 12 shows an example of... 

Multiphase catalysis occurs in C02/water by adding surfactants, which form micelles that disperse catalysts in pressurised C02/water mixtures. This is known for homogeneous toluene oxidation,toluene oxidation on immobilised micelles, oxybromination of phenol and aniline derivatives, or enzyme catalysis. 

The deoxy-oxy cycle was repeated at 1-min intervals and recorded 1.2 X 10 times (about 6 months) by changing the atmosphere of the cobalt-porphyrin polymer membrane from reduced pressure (about 2 cm Hg) to laboratory air pressure (76 cm Hg) at ambient temperature. Lifetime or half-life periods for the oxygen-binding ability were estimated to be 6 months for Structure (6) in the solid membrane state. The corresponding cobalt-porphyrin (6) in homogeneous toluene solution was able to repeat the oxy-deoxy cycle with a lifetime close to only 1 day. 

Nitrations can be performed in homogeneous media, using tetramethylene sulfone or nitromethane (nitroethane) as solvent. A large variety of aromatic compounds have been nitrated with nitronium salts in excellent yields in nonaqueous media. Sensitive compounds, otherwise easily hydroly2ed or oxidized by nitric acid, can be nitrated without secondary effects. Nitration of aromatic compounds is considered an irreversible reaction. However, the reversibihty of the reaction has been demonstrated in some cases, eg, 9-nitroanthracene, as well as pentamethylnitrobenzene transnitrate benzene, toluene, and mesitylene in the presence of superacids (158) (see Nitration). 

The low temperature limitation of homogeneous catalysis has been overcome with heterogeneous catalysts such as modified Ziegler-Natta (28) sohd-supported protonic acids (29,30) and metal oxides (31). Temperatures as high as 80°C in toluene can be employed to yield, for example, crystalline... 

The reactions of oxiranes with thiocyanate ion or with thiourea are usually done in homogeneous solution in water, alcohols or alcohol-acetic acid. The use of silica gel as a support for potassium thiocyanate in toluene solvent is advantageous for the simple work-up (filtration and evaporation of solvent) (80JOC4254). A crown ether has been used to catalyze reactions of potassium thiocyanate. 

Titrimetric apparatus see Graduated glassware Toluene-3,4-dithiol see Dithiol Tongs for crucibles and beakers, 98 Transmittance 648 conversion to absorbance, 709 Triangulation 245 Triethanolamine 317 Tri-n-butyl phosphate 171 Triethyl phosphate in homogeneous pptn. 425 Triethylenetetramine-fV,fV,fV, yV",fV", fV "-hexa acetic acid (TTHA) 57 Trifluoroacetylacetone 170, 237 Trimethyl phosphate in homogeneous pptn., 425... 

Homogeneous Solution Counting. This method is used for expls soluble in the toluene solvent. 

Soluble support-based synthetic approaches offer the advantages of both homogeneous solution-phase chemistry (high reactivity, ease of analysis) and solid-phase synthesis (large excess of reagents, simple product isolation and purification) [98,99]. As a representative example, PEG, one of the most widely used soluble polymers, has good solubility in most organic solvents (i.e., dichloromethane, acetonitrile, dimethylformamide, and toluene), but it... 

The term IPN was first used in 1960 to describe the apparently homogeneous product obtained from styrene crosslinked with divinylbenzene. IPNs were prepared from this system by taking a crosslinked poly(styrene) network and allowing it to absorb a controlled amount of styrene and a 50% divinylbenzene-toluene solution containing initiator. Polymerisation of this latter component led to the formation of an IPN, the density of which was... 

The cyclopropanation of 1-trimethylsilyloxycyclohexene in the present procedure is accomplished by reaction with diiodomethane and diethylzinc in ethyl ether." This modification of the usual Simmons-Smith reaction in which diiodomethane and activated zinc are used has the advantage of being homogeneous and is often more effective for the cyclopropanation of olefins such as enol ethers which polymerize readily. However, in the case of trimethylsilyl enol ethers, the heterogeneous procedures with either zinc-copper couple or zinc-silver couple are also successful. Attempts by the checkers to carry out Part B in benzene or toluene at reflux instead of ethyl ether afforded the trimethylsilyl ether of 2-methylenecyclohexanol, evidently owing to zinc iodide-catalyzed isomerization of the initially formed cyclopropyl ether. The preparation of l-trimethylsilyloxybicyclo[4.1.0]heptane by cyclopropanation with diethylzinc and chloroiodomethane in the presence of oxygen has been reported. "... 

In addition, the most efficient mem-ligand depicted above was successfully applied, in 2006, to the alkynylation of ketones. Thus, Liu et al. showed that this ligand was able to catalyse the enantioselective addition of phenylacetylene to various ketones, using Cu(OTf)2 as the starting base in toluene. The results were excellent and homogeneous not only for substituted aryl alkyl ketones, but also for aliphatic methyl ketones (Scheme 4.6). 

The sample is homogenized with acetonitrile. An aliquot of the extract is evaporated to dryness and the residual material is dissolved in ethyl acetate-toluene (3 1, v/v), and subjected to cleanup by gel permeation chromatography (GPC). After GPC, the sample is subjected to an alumina and Florisil SPE cleanup procedure. The concentrated eluate is analysed by gas chromatography/thermionic nitrogen-specific detection (GC/TSD). 

Macerated plant material is homogenized with a mixture of methanol and 1.2N hydrochloric acid (HCl) in water (4 1, v/v) and then with methanol. An internal standard solution is added to the filtrate and the filtrate is adjusted to a constant volume. A portion of the filtrate is rotary evaporated to dryness and hexane is added to the extract before a Florisil cleanup procedure is performed. The extract is dissolved in toluene for analysis by GC/MS in the negative chemical ionization (NCI) mode. 

While ephedrine derivatives showed some selectivity, the most promising results were obtained with cinchona alkaloids. Lithium alkoxides and lithium acetylides (n-BuLi or LiHMDS used to deprotonate both the acetylene and the alcohol) gave better results than the corresponding sodium or magnesium salts. Higher enan-tioselectivity was obtained in THF (homogeneous) than in toluene or diethyl ether (heterogeneous). 

Free radical copolymerizations of the alkyl methacrylates were carried out in toluene at 60°C with 0.1 weight percent (based on monomer) AIBN initiator, while the styrenic systems were polymerized in cyclohexane. The solvent choices were primarily based on systems which would be homogeneous but also show low chain transfer constants. Methacrylate polymerizations were carried out at 20 weight percent solids... 

Fish tissue is homogenized with a Polytron apparatus using methanol as a solvent, or extracted in a ball mill with hexane. The extracts are evaporated to dryness, dissolved in ethyl acetate toluene, and cleaned up on a gel permeation column followed by an alumina column. Analysis is performed by GC/NPD (Muir et al. 1981). Recovery is acceptable (79-97%) and limit of detection is 10 ng/g (Muir et al. 1981). 

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