Aqueous solutions of organic compounds

Previous work in the area of high-pressure phase equilibrium of aqueous solutions of organic compounds with supercritical fluids... 

Berlin, A. (1986). Kinetics of radical-chain decomposition of persulfate in aqueous solutions of organic compounds. Kinetic Catal. 27,34-39. 

Larcbet C, Bmn JP, Bulvestre G, and Auclair B. Sorption and pervaporation of dilute aqueous solutions of organic compounds through polymer membranes. J Membr Sci 1985 25 55-100. 

An efficient solution for the subtraction method was proposed by Bassette and Whit-nah [16]. The reactions were conducted in a system containing two phases water and carbon tetrachloride. The test mixture, which consisted of an aqueous solution of organic compounds, was used as one of the two phases (aqueous). After shaking and separation of the layers, the carbon tetrachloride was analysed with the extracted compounds by GC (see Fig. 5.3A). 

Steady-state galvanostatic polarization measurements were conducted on a series of aqueous solutions of organic compounds in contact with Pt-alloy-type gas diffusion electrodes under acidic conditions to characterize their electro-oxidation behavior. A number of potential fuels were studied, including dioxane, tetrahydrofuran, 1,2-dimethoxyethane, dimethoxymethane, trimethyl orthoformate, trioxane, and methanol, and prepared in dilute aqueous solutions of sulfuric acid and triflic acid. Many polarization measurements were in the... 

For aqueous solutions of organic compounds the influence of added salts on the mutual miscibility has also been studied under pressure in some cases. Figure 15 shows results obtained by Engels for the 3-methylpyridine + HjO system with addition of potassium iodide and sodium sulphate, the mass ratio of water to 3-methylpyridine being kept constant at a value of 70/30. The high-pressure immiscibility of the salt-free system (see Figure 9c) is displaced to... 

Why do very few aqueous solutions of organic compounds conduct electricity ... 

In the case of aqueous solutions of organic compounds, the determination of yields was often effected for onlv a single concentration of the solute. On another hand, the yields were frequently indicated by the authors only for some of the formed products. Sometimes, only the function of the formed product (aldehyde, acid,...) was identified. Although these determinations present merely a limited interest, they were given because ihev nevertheless point out the qualitative behavior of the compounds. 

PTFE membranes were plasma grafted with acrylamide and sodium 4-styrene-sulfonate (NaSS), and showed a superior performance to pervaporation dehydration for various aqueous solutions of organic compounds (Di et al. 2006). In particular, the protonized PTFE-g-NaSS membrane exhibited excellent properties, giving a permeation flux of 422 g/m h and a separation factor of 4491 in the pervaporation of a 90 wt% aqueous solution of isopropanol at 65°C. 

At present, GAC is used most frequently for analysis of volatile compounds with various isotope compositions, of inorganic and organic gases, of volatile organic polar compounds, and of aqueous solutions of organic compounds. 

In general, aqueous solutions of organic compounds are most likely to give foam. 

Jaeger and co-workers studied the regioselectivity of the reaction of a surfactant diene with a surfactant dienophile in micellar media" ". The orientational effects in the aggregates could result in an increase in the regjoselectivity in aqueous solutions of these compounds as compared to the reaction in organic media. 

Cabani, S., Conti, G., and Eepori, L. Thermodynamic study on aqueous dilute solutions of organic compounds. Part 2. - Cyclic ethers, Trans. Faraday Soc., 67 1943-1950, 1971. 

Before we deal with these molecular aspects in detail, it is instructive to inspect the enthalpic () and entropic (-T Sj,j,) contributions to the excess free energies of various organic compounds in aqueous solution (Table 5.3). Values representative of saturated aqueous solutions of the compounds have been derived from measurements of the enthalpies of dissolution of the liquids (i.e., = AwJ //, Fig. 5.1) or solids (// ... 

To estimate the size column required to isolate more of this polar material, we used information published by Thurman et al. (16), who described an empirical relationship between aqueous solubility of organic compounds and capacity factors on XAD-8 resin. They defined capacity factor as the mass of solute sorbed on the resin divided by the mass of solute present in the void volume of the column at the 503> breakthrough point. On the basis of their data, a substance having a capacity factor of 1000 will have a solubility of about 1 X 10-3 mol/L. Examples of compounds having solubility in this range are methyl benzoate, 2,4,6-trichlorophenol, and chlorobenzene. 

Reference electrodes are divided Into two groups. One comprises the saturated calomel electrode, its variants (such as the "lithium S.C.E.", Hg/Hg2Cl2(s.), LiCl( s)> and others of the same ilk), and the normal hydrogen electrode. These are almost Invariably prepared with water, so that their use with a non-aqueous solution entails a liquid-junction potential between the non-aqueous solution of the compound being studied and the aqueous solution In the reference electrode. Some workers have sought to circumvent this by preparing similar electrodes In the same solvents or solvent mixtures that contain the compounds they study when this has been done, the symbol "(o)" (for "organic") follows the abbreviation that would denote the ordinary aqueous form of the reference electrode. 

Aminopenicillanic acid (2.16 g) is dissolved in 20 ml of a one molar aqueous solution of potassium bicarbonate and 10 ml of acetone. The resultant solution is cooled in an ice-water bath and to it is added with stirring a solution of 2.7 g of alpha-methoxy-3,4-dichloro-phenylacetyl chloride in 10 ml of acetone. The pH is adjusted to 7-8 and upon completion of the addition the reaction medium is stirred for 15 min at ice bath temperature and then for 2.5 h at room temperature, maintaining the pH range between 7 and 8. The solution is extracted once with ether and then adjusted to pH 2.5 with 20% phosphoric acid. The acidic solution is extracted once with 30 ml of butyl acetate and again with 10 ml of butyl acetate. These combined butyl acetate extracts are thereafter successively washed twice with water and reextracted at pH 7 with 0.5 N aqueous potassium hydroxide solution. The aqueous layer is washed twice with ether and the remaining organic solvent is then removed by evaporation under reduced pressure. The washed aqueous layer is then lyophilized and the residue thus obtained taken up in acetone. The crystal line product is collected by filtration and dried to yield the potassium salt of 6-(a-methoxy-3,4-dichlorophenylacetamido)penicillanic acid. Upon treatment with mineral acid of an aqueous solution of the compound so prepared, there is obtained the free acid, 6-(a-methoxy-3,4-dichlorophenylacetamido)penicillanic acid. 

An inert SSE of great utility in cathodic reductions is a concentrated solution of a hydrotropic quaternary ammoniumsalt, e.g. tetrabutylammonium tosylate, in water 16 Such a solution has solvating properties approaching those of an organic solvent and hence enables one to obtain fairly concentrated homogeneous solutions of organic compounds in an aqueous medium. 

Crystals of cobalt(III) sulfate 18-hydrate decompose at room temperature within a few hours, but they can be stored in a refrigerator for 3 to 4 days without decomposing noticeably. Aqueous solutions of the compound evolve oxygen, the reaction occurring instantaneously in warm water and rapidly even in cold water. Suspensions in cold 10 N sulfuric acid decompose very slowly. Cobalt(III) sulfate oxidizes many organic compounds very vigorously.1... 

Buonomenna, M.G., Lopez, L.C., DavoU, M., Favia, R, d Agostino, R. and Drioli, E. 2009. Polymeric membranes modified via plasma for nanofiltration of aqueous solution containing organic compounds. MicmporMesoporMMer 2. ... 

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