Methanol ethanol mixtures

Site-selection spectroscopy Maximum selectivity in frozen solutions or vapor-deposited matrices is achieved by using exciting light whose bandwidth (0.01-0.1 cm-1) is less than that of the inhomogeneously broadened absorption band. Lasers are optimal in this respect. The spectral bandwidths can then be minimized by selective excitation only of those fluorophores that are located in very similar matrix sites. The temperature should be very low (5 K or less). The techniques based on this principle are called in the literature site-selection spectroscopy, fluorescence line narrowing or energy-selection spectroscopy. The solvent (3-methylpentane, ethanol-methanol mixtures, EPA (mixture of ethanol, isopentane and diethyl ether)) should form a clear glass in order to avoid distortion of the spectrum by scatter from cracks. 

The low-temperature photolysis at —150 °C in an ethanol-methanol mixture containing trifluoroacetic acid (0.01 M) adds another dimension to nitrosamine chemistry163 irradiation at 313 nm under these conditions gives a new species showing absorption at 391,... 

Fig. 7. Antiferromagnetic coupling. Absorption spectra of (NHj CrOCrfNHj),4 in 4 1 ethanol methanol mixture. The upper curve is measured at 230 K and the lower curve at 121 K. Reprinted with permission from Glerup, J., Acta Chem. Scand. 26, 3775 (1972).

Toluene solvent at room temperature toluene/ethanol/ methanol mixture (5 4 1) at 77 K b Lowest-energy absorption maximum with s > 1500 JvT1 cnr1 c Oxygen-free solvent... 

Reactions of ethanol-methanol mixtures were carried out with recovered CM catalyst at various temperatures. Several variations of the starting composition were utilized at 360°C. The results are shown in Table 1. The reaction at 310°C gave a very low conversion of the ethanol with small amounts of the higher alcohols being formed. The poor mass balance was assumed to have resulted from the formation of acetaldehyde, which was not analyzed in this experiment. 

Figure 1.2. Comparison of the fluorescence excitation and emission spectra of hypericin (a) and hypocrellin (b) in a 1 1 ethanol/methanol mixture at room temperature. The excitation spectra were measured at 295 K (solid line) and at 77 K (dashed line). The excitation spectra were monitored at 650 nm at 295 K and at 620 nm at 77 K.

The elaborated quinoline hydrochloride (242) was reacted with NaOMe in an ethanol/methanol mixture, followed by treatment with AcOH to give the pyridotriazinone (187). Subsequent treatment with POCl3 yielded the chloro derivative (186) <72GEP(0)2216241). 

Other examples can be given concerning the coupling of arylbromides [19] with the use of nickel metal catalysts. Reactions of this type may be achieved in protic media (20 80 Dimethylformamide (DMF)/ethanol or 50 50 ethanol/methanol mixture) with yields comparable with those usually found in aprotic media. (In... 

Such measurements at high pressures do not present any special difficulty since commercial spectrometers will accept most types of high-pressure cells in the experimental space with suitable high-pressure windows (see Section 5.3). Nevertheless, adequate pressure-transmitting fluids must be used for the study of solids, and this excludes organic fluids—such as the pentane-isopentane or the ethanol-methanol mixtures which are commonly used in the visible region—since their i.r. absorption bands preclude their use. For... 

With existing synchrotron sources, the size of the spot at the polychromatic focus point (the sample location) is several hundreds of micrometres, which is usually larger than the hole in the gasket of a DAC. Thus, powder samples in a suitable liquid medium (an ethanol-methanol mixture or silicone oil) are usually used to fill the hole entirely. Under such conditions, spectra such as those shown in Fig. 3.35 can be obtained in a matter of minutes. With the advent of the third-generation synchrotrons with high brilliance, the spot size... 

Rajesh, H. aiid Ozkan, U.S. (1993). Complete oxidation of etlianol, acetaldehyde, and ethanol/methanol mixtures over copper oxide and copper-cliromium oxide catalysts. Ind. Eng. Chem. Res. 32, 1622-1630. 

Example 2,2 Suppose an acetone/ethanol/methanol mixture of composition [0.3,0.3] is to be fed to a distillation column for separation. Determine... 

Principle of IR microscopy for the determination of mixed-gas diffusion coefficients and adsorption equilibria. A big single crystal (here ZIF-8 of 200pm size) is brought in the IR beam and gas adsorption starts. The IR absorbance is molecule-selective this means that the simultaneous adsorption of an ethanol/methanol mixture can be followed as a function of time and position. 

The most conunonly used solvents for the study of the laser action are a 2 1 1 mixture of jS-ethoxypropionitrile, j8-ethojgfethanol and acetonitrile (EAA), a 1 1 1 mixture of proprion-itrile, butyronitrile and isobutyronitrile ( nitrile solvent ), a 3 1 ethanol-methanol mixture, a 3 1 ethanol-DMF mixture, and acetonitrile. Some of the mixed solvent systems remain liquid to temperatures as low as -150 °C. However, the /3-diketonate complexes are not always stable for a long time in such solutions. For instance, Schimitschek et al. (1965b) mention that emopimn(III) j8-diketonate complexes degrade in the 3 1 ethanol methanol mixture. Fry and Pirie (1965) foimd that in this alcohol mixture, [Eu(bzac)3(H20)] decomposed upon heating the solution to 70 °C or upon irradiation with ultraviolet radiation. The main decomposition products were ethyl acetate and acetophenone, which indicates that benzoylacetonate underwent a reverse Claisen condensation. Brecher et al. (1965) discussed the dissociation in solution of the tetrakis complexes into mixtures of non-lasing tris complexes and free jS-diketonate anions. 

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