Solubility stoichiometric

Kabanov AV, Bronich TK, Kabanov VA, Yu K, Eisenberg A. Soluble stoichiometric complexes from poly(A-ethyl-4-vinylpyridinium) cations and poly(ethylene ox de)-block-polymethacrylate anions. Macromolecules 1996 29 8999. 

Kabanov, A.V., Bronich, T.K., Kabanov, V.A., Yu, K. and Eisenberg, A. (1996) Soluble stoichiometric complexes from poly(N-ethyl-4-vinylpyridinium) cations and polyethylene oxide)-Wock-polymethacrylate anions. Macromolecules, 29, 6797-6802. 

A promising way to improve the colloidal stability is the use of double hydrophilic polyelectrolytes. Kabanov et al. [87] reported on soluble stoichiometric PECs between diblock copolymers containing sodium poly(meth-... 

Kabanov et al. [59] reported nonstoichiometric complexes between cationic poly (V-ethyl-4-vinylpyridinium) and anionic block copolymer poly(ethyleneoxide-co-methacrylate). This system revealed highly soluble stoichiometric PEC particles. 

Matralis A, Sotiropoulou M, Bokias G, Staikos G (2006) Water-soluble stoichiometric polyelectrolyte complexes based on cationic comb-type copolymers. Macromol Chem Phys 207 1018-1025. doi 10.1002/macp.200600803... 

Stoichiometric air—fuel volumetric ratio water solubility sulfur content, wt %... 

The stoichiometric reaction of y -diisopropenylbenzene [3748-13-8] with two moles of j -butyUithium in the presence of triethylamine has been reported to produce a useful, hydrocarbon-soluble dilithium initiator because of the low ceiling temperature of the monomer (78,79) which is analogous in stmcture to a-methylstyrene however, other studies suggest that oligomerization occurs to form initiators with functionahties higher than two (80). 

Fumarates. lron(Il) fumarate [141 -01 -5], Fe(C4H20, is prepared by mixing hot aqueous solutions of sodium fumarate and iron(Il) sulfate followed by filtration of the resulting slurry. It has limited solubiUty in water but is more soluble in acid solution. The compound is red-orange to red-brown and finds uses as a hematinic. A non stoichiometric compound [7705-12-6] and iron(Ill) fumarate [52118-11-3], Fe2(C4H20 3, are also available. 

Silver Cyanide. Silver cyanide, AgCN, forms as a precipitate when stoichiometric quantities of silver nitrate and a soluble cyanide are mixed. Sdver(I) ion readily forms soluble complexes, ie, Ag(CN) 2 01 Ag(CN) 2> die presence of excess cyanide ion. 

Silver Thiocyanate. Silver thiocyanate, AgSCN, is formed by the reaction of stoichiometric amounts of silver ion and a soluble thiocyanate. 

Calcareous minerals and evaporite minerals (haUdes, gypsum) are very soluble and dissolve rapidly and, in general, congmendy, ie, yielding upon dissolution the same stoichiometric proportions in the solution as the proportions in the dissolving mineral and without forming new soHd phases (Fig. 

Calcareous minerals such as gypsum [13397-24-5] when added in stoichiometric amounts relative to the barite impurities, reduce acid-soluble barium losses (16). 

Precipitation. Filtered overflow from the first clarifier, 20% BaS solution, is fed to an agitated tank where, on tight control, carbonate values are added in slight excess of stoichiometric requirements. The excess carbonate suppresses soluble barium which would otherwise later precipitate in equipment. 

Bismuth ttiiodide may be prepared by beating stoichiometric quantities of the elements in a sealed tube. It undergoes considerable decomposition at 500°C and is almost completely decomposed at 700°C. However, it may be sublimed without decomposition at 3.3 kPa (25 mm Hg). Bismuth ttiiodide is essentially insoluble in cold water and is decomposed by hot water. It is soluble in Hquid ammonia forming a red triammine complex, absolute alcohol (3.5 g/100 g), benzene, toluene, and xylene. It dissolves in hydroiodic acid solutions from which hydrogen tetraiodobismuthate(Ill) [66214-37-7] HBil 4H2O, may be crystallized, and it dissolves in potassium iodide solutions to yield the red compound, potassium tetraiodobismuthate(Ill) [39775-75-2] KBil. Compounds of the type tripotassium bismuth hexaiodide [66214-36-6] K Bil, are also known. 

Liquid-phase chlorination of butadiene in hydroxyhc or other polar solvents can be quite compHcated in kinetics and lead to extensive formation of by-products that involve the solvent. In nonpolar solvents the reaction can be either free radical or polar in nature (20). The free-radical process results in excessive losses to tetrachlorobutanes if near-stoichiometric ratios of reactants ate used or polymer if excess of butadiene is used. The "ionic" reaction, if a small amount of air is used to inhibit free radicals, can be quite slow in a highly purified system but is accelerated by small traces of practically any polar impurity. Pyridine, dipolar aptotic solvents, and oil-soluble ammonium chlorides have been used to improve the reaction (21). As a commercial process, the use of a solvent requites that the products must be separated from solvent as well as from each other and the excess butadiene which is used, but high yields of the desired products can be obtained without formation of polymer at higher butadiene to chlorine ratio. 

The simplest method to measure gas solubilities is what we will call the stoichiometric technique. It can be done either at constant pressure or with a constant volume of gas. For the constant pressure technique, a given mass of IL is brought into contact with the gas at a fixed pressure. The liquid is stirred vigorously to enhance mass transfer and to allow approach to equilibrium. The total volume of gas delivered to the system (minus the vapor space) is used to determine the solubility. If the experiments are performed at pressures sufficiently high that the ideal gas law does not apply, then accurate equations of state can be employed to convert the volume of gas into moles. For the constant volume technique, a loiown volume of gas is brought into contact with the stirred ionic liquid sample. Once equilibrium is reached, the pressure is noted, and the solubility is determined as before. The effect of temperature (and thus enthalpies and entropies) can be determined by repetition of the experiment at multiple temperatures. 

The advantage of the stoichiometric technique is that it is extremely simple. Care has to be taken to remove all gases dissolved in the IL sample initially, but this is easily accomplished because one does not have to worry about volatilization of the IL sample when the sample chamber is evacuated. The disadvantage of this technique is that it requires relatively large amounts of ILs to obtain accurate measurements for gases that are only sparingly soluble. At ambient temperature and pressure, for instance, 10 cm of l-n-butyl-3-methylimida2olium hexafluorophosphate ([BMIM][PFg]) would take up only 0.2 cm of a gas with a Henry s law constant of... 

The compound (NIDsNbaOFig can be prepared by adding ammonium fluoride, NH4F, to a solution containing Nb (3.20 M/l) and F (27.10 M/l). The solubility isotherm (25°) of this compound is presented in Fig. 5. The minimum point on the solubility isotherm approximately corresponds to the stoichiometrical ammonium-niobium ratio of the compound (NfLOsNbsOFig. 

Of course, the most practical and synthetically elegant approach to the asymmetric Darzens reaction would be to use a sub-stoichiometric amount of a chiral catalyst. The most notable approach has been the use of chiral phase-transfer catalysts. By rendering the intermediate etiolate 86 (Scheme 1.24) soluble in the reaction solvent, the phase-transfer catalyst can effectively provide the enolate with a chiral environment in which to react with carbonyl compounds. 

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