Aqueous multicomponent

Gu Y, De Sousa R, Frapper P, Bachmann C, Barrault J, Jer me F (2009) Catalyst-free aqueous multicomponent domino reaction from formaldehyde and 1,3-dicarbonyls derivatives. Green Chem 11 1968-1972... 

The solubilities of gases, liquids, and solids in multi-component solvents constitute important issues in science and technology. The aqueous multicomponent solutions represent a meaningful example because the overwhelming majority of solutions of biological and environmental interest are aqueous multicomponent solutions. 

Laufenberg G., Flausmanns S., Kunz B. (1996), The influence of intermolecular interactions on the selectivity of several organic acids in aqueous multicomponent systems during reverse osmosis. 

In similar aqueous multicomponent reactions, a spectrum of pentacycHc isoindazole-fused benzo[h,e][l,4]diazepines 165 (Scheme 12.67) [91] and... 

Double-decker phthalocyanines are soluble in a narrow range of solvents and are insoluble in water, however, we have developed methods for preparing aqueous multicomponent systems based on lanthanide complexes phthalocyanines double-decker. Macromolecular stmctures (proteins, polymers), supiamolecular stmctures (micelles) and nanosized silica were used as solubilizers. 

Y. Gu, R. de Sousa, G. Frapper, C. Bachmann, J. Barrault, F. Jerome, Green Chem. 2009, 11, 1968-1972. Catalyst-free aqueous multicomponent domino reactions from formaldehyde and 1,3-dicarbonyl derivatives. 

Actual water treatment challenges are multicomponent. For example, contamination of groundwater by creosote [8021-39-4], a wood (qv) preservative, is a recurring problem in the vicinity of wood-preserving faciUties. Creosote is a complex mixture of 85 wt % polycycHc aromatic hydrocarbons (PAHs) 10 wt % phenohc compounds, including methylated phenols and the remaining 5 wt % N—, S—, and O— heterocycHcs (38). Aqueous solutions of creosote are therefore, in many ways, typical of the multicomponent samples found in polluted aquifers. 

Akita Another case of multicomponent dilute diffusion of significant practical interest is that of gases in aqueous electrolyte solutions. Many gas-absorption processes use electrolyte solutions. Akita presents experimentally tested equations for this case. 

Many electrochemical devices and plants (chemical power sources, electrolyzers, and others) contain electrolytes which are melts of various metal halides (particularly chlorides), also nitrates, carbonates, and certain other salts with melting points between 150 and 1500°C. The salt melts can be single- (neat) or multicomponent (i.e., consist of mixtures of several salts, for their lower melting points in the eutectic region). Melts are highly valuable as electrolytes, since processes can be realized in them at high temperatures that would be too slow at ordinary temperatures or which yield products that are unstable in aqueous solutions (e.g., electrolytic production of the alkali metals). 

Diffusion of ions can be observed in multicomponent systems where concentration gradients can arise. In individnal melts, self-diffnsion of ions can be studied with the aid of radiotracers. Whereas the mobilities of ions are lower in melts, the diffusion coefficients are of the same order of magnitude as in aqueous solutions (i.e., about 10 cmVs). Thus, for melts the Nemst relation (4.6) is not applicable. This can be explained in terms of an appreciable contribntion of ion pairs to diffusional transport since these pairs are nncharged, they do not carry cnrrent, so that values of ionic mobility calculated from diffusion coefficients will be high. 

Reed, M.H. (1982) Calculation of multicomponent chemical equilibria and reaction processes in systems involving minerals, gases and an aqueous phase. Geochim. Cosmochim. Acta, 46, 513-528. 

The most common method of isolation and sample cleanup involves contacting a filtered aqueous solution with an appropriate immiscible organic solvent in a. aboratory separatory funnel of appropriate size. Some specific examples are discussed later. With multicomponent samples a single solvent or solvent mixture is unlikely to extract all components equally causing discrimination. Ihis discrimination may be useful if the solvent discriminates against the extraction of solutes that are not of interest in the analysis. 

Fowle and Fein (1999) measured the sorption of Cd, Cu, and Pb by B. subtilis and B. licheniformis using the batch technique with single or mixed metals and one or both bacterial species. The sorption parameters estimated from the model were in excellent agreement with those measured experimentally, indicating that chemical equilibrium modeling of aqueous metal sorption by bacterial surfaces could accurately predict the distribution of metals in complex multicomponent systems. Fein and Delea (1999) also tested the applicability of a chemical equilibrium approach to describing aqueous and surface complexation reactions in a Cd-EDTA-Z . subtilis system. The experimental values were consistent with those derived from chemical modeling. 

This choice of basis follows naturally from the steps normally taken to study a geochemical reaction by hand. An aqueous geochemist balances a reaction between two species or minerals in terms of water, the minerals that would be formed or consumed during the reaction, any gases such as O2 or CO2 that remain at known fugacity as the reaction proceeds, and, as necessary, the predominant aqueous species in solution. We will show later that formalizing our basis choice in this way provides for a simple mathematical description of equilibrium in multicomponent systems and yields equations that can be evaluated rapidly. 

The examples in the previous section demonstrate that nonunique solutions to the equilibrium problem can occur when the modeler constrains the calculation by assuming equilibrium between the fluid and a mineral or gas phase. In each example, the nonuniqueness arises from the nature of the multicomponent equilibrium problem and the variety of species distributions that can exist in an aqueous fluid. When more than one root exists, the iteration method and its starting point control which root the software locates. 

A microemulsion droplet is a multicomponent system containing oil, surfactant, cosurfactant, and probably water therefore there may be considerable variation in size and shape depending upon the overall composition. The packing constraints which dictate size and shape of normal micelles (Section 1) should be relaxed in microemulsions because of the presence of cosurfactant and oil. However, it is possible to draw analogies between the behavior of micelles and microemulsion droplets, at least in the more aqueous media. 

The use of phenolic polymers in photocrosslinkable systems usually involves multicomponent systems which incorporate polyfunctional low molecular weight crosslinkers. For example, Feely et al. [9] have used hydroxymethyl melamine in combination with a photoactive diazonaphthoquinone which produces an indene carboxylic acid upon irradiation to crosslink a novolac resin. Similarly, Iwayanagi et al. [10] have used photoactive bisazides in combination with poly(p-hydroxy-sty-rene) to afford a negative-tone resist material which does not swell upon development in aqueous base. 

Meissner, H. P. and C. L. Kusik, "Activity Coefficients of Strong Electrolytes in Multicomponent Aqueous Solutions," AIChE J., 1972, 18, 294. 

Prausnitz, "Vapor-Liquid Equilibria in Multicomponent Aqueous Solutions of Volatile Weak Electrolytes," AIChE J., 1978, 24, 966. 

This interaction between physical and chemical equilibria complicates considerably the description of vapor-liquid equilibria in multicomponent aqueous solutions. The development of thermodynamic correlations for those equilibria is also hindered by the limited experimental material available on that subject. 

This contribution describes and compares three procedures for representing vapor-liquid equilibria in multicomponent aqueous solutions of volatile weak electrolytes. Starting from the basic thermodynamic relations, the approximations and simplifications applied by van Krevelen, Hoftijzer and Huntjens ( ), Beutier and Renon (2) and Edwards, Maurer, Newman and Prausnitz (3) are discussed the necessary information for using these correlations is compiled. Results calculated with these procedures are discussed and compared with literature data. 

In a multicomponent aqueous system encountering ammonia, carbon dioxide, hydrogen sulfide and sulfur dioxide, the vapor phase contains molecules of only five different species, e.g. NH3, CO2, H2S, SO2 and H20, while in the liquid phase 15 different species are present besides the molecular species also 10 ionic spe-... 

It is evident from the title of this symposium that as a result of recent requirements to reduce pollutant levels in process wastewater streams, improved techniques for predicting the vapor-liquid-solid equilibria of multicomponent aqueous solutions of strong and/or weak electrolytes are needed. In addition to the thermodynamic models necessary for such predictions, tools have to be developed so that the engineer or scientist can use these thermodynamic models correctly and with relative ease. 

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