Temperature dependence, phase

Nuzzo R G, Korenic E M and Dubois L H 1990 Studies of the temperature-dependent phase behaviour of iong chain / -aikyi thioi monoiayers on goid J. Chem. Phys. 93 767-73... 

Temperature-dependent phase behavior was first applied to separate products from an ionic liquid/catalyst solution by de Souza and Dupont in the telomerization of butadiene and water [34]. This concept is especially attractive if one of the substrates shows limited solubility in the ionic liquid solvent. 

Thallous halides offer a unique possibility of studying the stereochemistry of the (chemically) inert electron pair, since their structures and their pressure and temperature-dependent phase transitions have been well established. Thallium (1) fluoride under ambient conditions, adopts an orthorhombic structure in the space group Pbcm which can be regarded as a distorted rocksalt structure (Fig. 2.4). In contrast to TIF, the thallium halides with heavier halogens, TlCl, TlBr and Til, adopt the highly symmetric cubic CsCl structure type under ambient conditions [46]. Both TlCl and TlBr, at lower temperatures, undergo phase transitions to the NaCl type of structure [47]. 

Experimental determination of a temperature depending phase diagram LC / LV / LK... 

A unique temperature dependent phase sequence hexagonal columnar - reentrant isotropic (Isore) - smectic A was observed by Szydlowska et al. for some c/,v-enaininoketone Ni(II) and Cu(II) complexes combining two fluorinated and two hydrocarbon chains (compound 171). Related complexes with only one RF-chain... 

Converse and Huber (1965), Robinson (1970), Mayur and Jackson (1971), Luyben (1988) and Mujtaba (1997) used this model for simulation and optimisation of conventional batch distillation. Domenech and Enjalbert (1981) used similar model in their simulation study with the exception that they used temperature dependent phase equilibria instead of constant relative volatility. Christiansen et al. (1995) used this model (excluding column holdup) to study parametric sensitivity of ideal binary columns. 

The Qnsager model is only able to describe the phase behaviour of low concentrated solutions. A second drawback is that it is athermal, and thus is not able to describe temperature dependent phase transitions, and accordingly cannot describe the occurrence of a clearing temperature. 

A comparison of the properties of the bulk micellar systems with those of the films in metastable equilibrium, in particular NBF, is of special interest. The existence of a correlation between the temperature dependent phase transition in NBF stabilised with phospholipids and the analogous phase transition taking place in the bulk phase is to be further discussed (see Section 3.4.4). Undoubtedly, for the systems considered the establishment of a similar correlation between the foam films and the bulk solubilising phases is worth studying. 

Hager, O., Eoces-Foces, C., Llamas-Saiz, A. L. and Weber, E. (1998). Temperature-dependent phase transitions in two crystaliine host-guest complexes derived from mandelic acid. Acta Crystallogr. B, 54, 82-93. [237]... 

The ID and 2D MAS NMR and powder X-ray diffraction have successfiilly been used to resolve the temperature dependent phase transformations of ZSM-11, to assign their space groups and isolate the temperature range of disorder. 

Fig. 2 Top solubilization of [Cu(bipy)Cl2] by a TSIL and the temperature dependent phase separation. Bottom liquid-liquid equilibrium phase diagram of the binary mixture TSIL-water. Figure adapted from [64]. Image Copyright American Chemical Society (2006). For color image see online version...

The vast majority of experiments now measure the temperature-dependent phase changes in images obtained using gradient echo sequences. In such a sequence, with an echo time TE, and spatially dependent temperature change Ar(x, y, z), the phase change is given by ... 

Optimal data acquisition parameters were derived by maximizing the S/N of the temperature-dependent phase difference images ... 

Zhi H, Lu C, Zhang Q, Luo J (2009) A new PEG-lOOO-based dicationic ionic liquid exhibiting temperature-dependent phase behavior with toluene and its application in one-pot synthesis of benzopyrans. Chem Commun 2878-2880... 

Stacking the isothermal Gibbs triangles on top of each other results in a phase prism (see Fig. 1.3(a)), which represents the temperature-dependent phase behaviour of ternary water-oil-non-ionic surfactant systems. As discussed above, non-ionic surfactants mainly dissolve in the aqueous phase at low temperatures (2). Increasing the temperature one observes that this surfactant-rich water phase splits into two phases (a) and (c) at the temperature T of the lower critical endpoint cepp, i.e. the three-phase body appears. Subsequently, the lower water-rich phase (a) moves towards the water corner, while the surfactant-rich middle phase (c) moves towards the oil corner of the phase prism. At the temperature Tu of the upper critical endpoint cepa a surfactant-rich oil phase is formed by the combination of the two phases (c) and (b) and the three-phase body disappears. Each point in such a phase prism is unambiguously defined by the temperature T and two composition variables. It has proved useful [6] to choose the mass fraction of the oil in the... 

Considering the phase behaviour of the system H20/NaCl (A)-n-decane (B)-AOT (D) as an example, the temperature-dependent phase behaviour of the system can be represented as a first approximation in an upright Gibbs phase prism, if the mixture of H20 and NaCl (often referred to as brine) is treated as a pseudo-component. It holds for the mass fraction of NaCl in the H20/NaCl mixture... 

If large quantities are used for technical processes, e.g. for cleaning, the recovery and reuse of the microemulsion or at least of a considerable amount of the most expensive components is desired. Therefore, strategies are needed to separate contaminants from the organic microemulsion components. Separation is usually more complicated than from ordinary solvents and often requires several steps [39, 40]. In particular, the separation of waste materials from the surfactants is usually very difficult or often even impossible. The temperature-dependent phase behaviour of bicontinuous microemulsions, however, can sometimes be beneficially used for separation [41]. Easy separation, at least from the unpolar solvent, can be achieved from microemulsions with supercritical liquids [42]. 

Polyethylene oxide) and poly(N-alkylacrylamide)s are known to undergo a temperature-dependent phase change whereupon they separate from an aqueous phase at increased temperatures [14]. This inverse temperature dependence, i.e., the occurrence of a lower critical solution temperature, can be related to an entropi-cally favorable decrease in hydrogen bonding between water and the polymer with increasing temperature. In order to exploit this physical property for catalyst recovery, Bergbreiter et al. attached phosphines covalently to commercially available PEO or PEO-b-PPO-b-PEO block copolymers [Schemes 1 and 2 PPO = polypropylene oxide)] [9a],... 

CNPyH][C104] Czupihski et al. Temperature dependant phase change monitored... 

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