Reactive binary mixtures

Most of what we know about solvent effects is a result of studies in which the reactivity is compared in a series of solvents. There are two main types of experimental design in one of these the reaction is carried out in different pure solvents in the other design the reaction is studied in mixed solvents, often a binary mixture whose composition is varied across the entire range. Experimental limitations often... 

Bajoras and Makuska investigated the effect of hydrogen bonding complexes on the reactivities of (meth)acrylic and isotonic acids in a binary mixture of dimethyl sulfoxide and water using IR spectroscopy (Bajoras and Makuska, 1986). They demonstrated that by altering the solvent composition it was possible to carry out copolymerization in the azeotropic which resulted in the production of homogeneous copolymers of definite compositions at high conversions. Furthermore, it was shown that water solvent fraction determines the rate of copolymerization and the reactivity ratios of the comonomers. This in turn determines the copolymer composition. 

Reactive extraction of lignin from red spruce has been studied using supercritical methylamine and methyla-mine-nitrous oxide binary mixtures. The wood residues and precipitated fractions after extractions have been characterized by chemical and spectroscopic procedures. 

The hydrogenation of dienes to monoenes introduces several problems of selectivity. Regioselective saturation of one of the double bonds is governed basically by the same effects that determine the relative reactivities of monoalkenes in a binary mixture that is, a terminal double bond is reduced preferentially to other, more substituted double bonds. During the reduction of a diene, a new competition also emerges since the newly formed monoene and the unreacted diene compete for... 

Since the rate of hydrogenation is sensitive to operating conditions (temperature, pressure, catalyst quantity, solvent and agitation), relative rates determined in competitive hydrogenation of binary mixtures are considered to be more reliable than measuring individual rates50. Relative reactivities thus measured are determined by the ratio of rate and adsorption constants. 

The proposed modeling approach has been validated for distillation of non-reactive mixtures. For this purpose, the use is made of the total reflux distillation data for the binary mixture chlorobenzene/ethylbenzene (CB/EB) and ternary mixture methanol/acetonitrile/water (MEOH/ACN/WATER) obtained by Pelkonen (1997) as well as for the ternary mixture methanol/ethanol/water (MeOH/EtOH/WATER) measured by Mori et al. (2006). The experiments of Pelkonen (1997) were carried out in a column of 100 mm diameter, equipped with Montz-Pak A3-500 structured packing. The measured concentrations, temperature and flow rates at the condenser outlet are used as input values for simulations. 

In the following, the strategy presented before will this time be applied for developing a process for the esterification of lauric acid with methanol. All the thermodynamic data for pure components and binary mixtures are available in Aspen Plus. A residue curve map of the reactive mixture at equilibrium can be computed as described in Appendix A. A useful representation can be done in reduced coordinates defined by Xx = water + add and X2 = add + ester. The diagram displayed... 

Binary copolymerization resembles distillation of a bicomponent liquid mixture, with a reactivity ratio corresponding to the ratio of vapor pressures of the pure components in the latter case. The vapor-liquid composition curves of ideal binary mixtures have no inflection points and neither do the polymer-composition curves for random copolymerizations, in which/ r2 — 1 (Fig. 7-1). For this reason, such comonomer systems are sometimes called ideal. 

L.V.C. Rees, J. Hampson, and P. Bruckner, Sorption of single gases and their binary mixtures in zeolites, in Zeolites Mocroporous Solids Synthesis, Structure and Reactivity (E.G. Dcrouane and F. Lemos, eds.), Kluwer Academic Publishers, Dordrecht, The Netherlands, 1992, p. 133. 

A more recent study has been made of the surface reactivity of several carbon fibres towards gaseous adsorbents. Heats of adsorption for water and for various organic gases were found not to vary significantly, but calculated adsorption coefficients showed that pre-oxidation enhanced the adsorption of polar adsorbates such as water, pyridine, and aniline. Kipling et a/. have shown that pre-treatment by oxygen can result in preferential adsorption of more polar components of a binary mixture. Care must be exercised, however, in that different surface complexes may promote specific adsorption of individual chemicals. ... 

Polymer blends and alloys have more complex behavior in the presence of fillers than the binary mixtures of polymer and filler. The same factors, such as filler distribution, filler-matrix interaction, filler-matrix adhesion, particle orientation, nucleation, chemical reactivity, etc. have influence on properties, but this influence is complicated by the fact that there are two or more polymers present which compete for the same filler particles. These complex interactions result in many interesting phenomena discussed below. 

Ionic Liquids as Binary Mixtures with Selected Molecular Solvents, Reactivity Characterisation and Molecular-Microscopic Properties... 

A special consideration related to BAN and its binary mixtures with molecular solvents allowed us to demonstrate that this protic IL can act both as Bronsted acid and nucleophile. The selected model reaction constitutes a suitable example of how the microscopic feature of a reactive system can be modified by adding aliquots of a protic IL to a molecular solvent. Moreover, the whole reactive system can be modulated with the aim not only to promote acid-catalysed reactions but also to generate nucleophilic species in situ. In this sense, the design of IL can be formulated according to the particular requirement of a reactive system. 

For process simulation, the thermodynamic properties of the quaternary mixture 1-hexanol + acetic add + hexyl acetate + water have to be known. The vapor-Uquid equilibrium model of that quaternary mixture is, as usual, parameterized based on information from the binary systems alone. There are six binary mixtures for a quaternary mixture, two of which are reactive in our example. The special challenges in the experimental determination of phase equilibria in reactive systems will be discussed later. Using typical G models, at least 12 parameters have to be adjusted to experimental binary data or estimated. Additionally, at least the... 

First, the role of reaction kinetics is analyzed considering RD processes for the simple reversible reaction Aj o Aj in an ideal binary mixture. The educt Aj is assumed to be the reaction component with the higher boiling point, so the product A2 is obtained in the distillate. The reaction can be carried out in an RD column sequence with an external recycling loop (Fig. 5.1), a non-RD column on top of a reactive reboiler (Fig. 5.2), or a full RD column (Fig. 5.3). More possible configurations are analyzed elsewhere [1]. 

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