Ethyleneglycol solutions

Fig. 13. Paramagnetic enhancements to solvent NMRD profiles for water solution of 00(0104)2 6H2O at 298 K (O) and for ethyleneglycol solutions at 264 K ( ) and 298 K ( ) 47).

Fig. 5.37. Solvent H NMRD profiles for ethyleneglycol solutions of Cu(ClC>4) 6H20 at 264 (A), 278 (D), 288 (A), 298 ( ) and 312 ( ) K as compared to those of water solution at 298 K (o) [81]. The solid lines are best fit curves obtained using an isotropic A value.

If the number of interacting protons is similar in water and in ethyleneglycol solutions, as it is for other aqua ions in viscous solvents, the large difference in relaxivity indicates that rso must be one order of magnitude shorter for Ni(II) in ethyleneglycol. This means that laiger distortions of the coordination sphere of the ion upon collisions with solvent molecules must occur. Therefore, rotation and viscosity affect the mechanisms of electron relaxation. 

The proton NMRD profile of an ethyleneglycol solution containing GdCb is reported in Fig. 5.53 at two different temperatures. The correlation time for electron relaxation, xv, is longer than in water. This could indicate that collisions of solvent molecules with the ion are slowed down in viscous solvents. r5o, which is related to the magnitude of the instantaneous ZFS induced by collisions, instead, does not change much. Therefore, the decrease of thermal motion as well as the... 

Ultrasonic effect on the catalytic efficiency of platinum nanoparticles in poly vinylpyrroUdone or ethyleneglycol solutions... 

Removal of the isopropylidene (acetonide) group. Hampton et al. found that for a given concentration of acid (0.01 N), the conversion of isopropylideneuridine (1) into uridine (2) proceeds ten times more rapidly in ethyleneglycol solution than in water. Methanol and ethanol were significantly less effective. 

Figure 934. Distribution of the electron-transfer distance Y r) = a(r, oo) for different values of the free energy change AG in ethyleneglycol solution with the acceptor concentration c = 0.3M. (Reproduced from [345b] with permission. Copyright (1996) by the American Chemical Society.)...

Blumenfeld LA, Davydov RM, Magonov SN, Vilu R (1974) Conformational changes of metalloproteins induced by electrons in water-ethyleneglycol solutions at low temperatures. Hemoglobin. II. FEES Lett 49 246-248... 

Burke and Lindow [1.13] showed, that certain bacteria (e. g. Pseudomonas syringae) can act as nuclei for crystallization if their surface qualities and their geometric dimensions are close to those of ice. Rassmussen and Luyet [1.14] developed a connection for solutions of water with ethyleneglycol (EG), glycerol (GL) and polyvinylpyrrolidone (PVP) between the subcooling down to the heterogeneous and homogeneous nucleation of ice. 

From DTA measurements phase diagrams can be constructed as shown for ethyleneglycol in Fig. 1.34. A solution of 40 % ethyleneglycol is only stabile in the glass phase below = -135 °C, at = -120 °C unfrozen water starts to crystallize, at = -65 °C a recrystallization is found, and at = —45 °C melting will start. As recrystallization is the growing of existing crystals, and not the nucleation of new ones, this event cannot be detected by DTA, but can be observed in a microscope when a transparent area becomes opaque. 

The proton ENDOR study of the chromyl ethyleneglycolate anion in ethanol reported by Mohl et al.293 presents the first successful adaptation of the ENDOR technique to a transition metal complex in liquid solutions. The aim of this work was to characterize the ENDOR relaxation behavior and to find optimum conditions for ENDOR detection. Two proton ENDOR lines with a hf splitting of ajj, = 1.74 MHz were observed. This is in agreement with a previous EPR study294 which had shown that all eight protons are equivalent. The optimum microwave and rf fields are both proportional to (Tr(g - geO rAj 2)1/2, where A denotes the dipolar part of the proton hfs tensor. For the chromyl ethyleneglycolate anion these two values have been calculated to — 8 10-6T and B = 2.7 mT. According to Mohl et al.293, successful proton... 

Coupling of an aryl 1-S-cellobioside to an affinity carrier was therefore expected to be useful in the chromatographic fractionation of endo and exo enzymes, e.g., from Tr. r. Preliminary tests indicated that CBH I and CBH II (prepurified by ion-exchange chromatography) were completely retained by the affinity support (4 -aminobenzyl 1-S-cellobioside coupled to Affigel-10 from Biorad). Desorption was achieved differentially by 0.1M lactose (elutes CBH I) and 0.01M cellobiose (elutes CBH I and CBH II). Attempts to elute the enzymes with 1M KC1, ethyleneglycol or glucose solutions were unsuccessful (11). 

Properties of Ethyleneglycol and its Aqueous Solutions , USBurStandards, Washington,... 

STD-286B (1 Dec 1967), Method 601.1.1, "Titanous Chloride (0.2N Standard Solution) 20) Frank pristera , 1 Expiosives in Vol 12 of Encyclopedia of Industrial Chemical Analysis, Wiley, NY (1971), pp443—45 (Nitroglycerin and Dynamites, Analysis) 445 (PETN) 445 fit 451 (Ethyleneglycol Nitrates) - 451 (Other organic nitrate esters) 451 (Ammonium Nitrate) 452—60 (Identification of explosives by infrared spectroscopy) 460—62 (Analysis of unknown HE s) 461—67 (Nitrogen content determinations) 467—70 (Other methods for quality control) 470—71 (67 references on analytical procedures)... 

The same observation can be made for more viscous liquids (ethyleneglycol, in the work by Hasseni et al., Figure 5.2-12, and an aqueous solution of ethyleneglycol, in the work of Wammes et al., Figure 5.2-13). 

Wammes et al. [34], by employing three different liquids (water - ethanol and 40 % ethyleneglycol aqueous solution) with 3 mm glass spheres, obtained experimentally determined static hold-up data. Figure 5.2-24 shows the values of the static holdup as a function of the Eotvos number together with data of other authors. Wammes et al. [34] concluded that the static liquid hold-up is not affected by the total reactor pressure. 

When the viscosity of the solution increases by using ethyleneglycol or glycerol water mixtures as solvent, the rotational correlation time increases. This determines (1) higher relaxivity values at low frequencies (2) a shift toward lower frequencies of the a>s dispersion (3) the appearance of a second dispersion (ascribed to the a>i dispersion) at high fields. Temperature dependence studies show that the observed rates are not controlled by exchange, but arise from variation of the rotational correlation time. 

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