Solution, stability

Under superacidic, low nucleophilicity so-called stable ion conditions, developing electron-deficient carbocations do not find reactive external nucleophiles to react with thus they stay persistent in solution stabilized by internal neighboring group interactions. 

Application of IP and NCS in conjunction with specification tolerance limits enables to substantiate acceptance criteria for linear regression metrological characteristics (residual standard deviation, correlation coefficient, y-intercept), accuracy and repeatability. Acceptance criteria for impurity influence (in spectrophotometric assay), solution stability and intermediate precision are substantiated as well. 

Mercaptan-inodified polychloroprenes provide lighter colour to solutions and are more resistant to discolouration than sulphur-modified polychloroprenes. Also mercaptan-modified polychloroprenes exhibit better ageing, and improved thermal and solution stability. 

Chemical Reactivity - Reactivity with Water Anhydrous grade dissolves with evolution of some heat Reactivity with Common Materials Metals slowly corrode in aqueous solutions Stability During Transport Stable Neutralizing Agents for Acids and Caustics Not pertinent Polymerization Not pertinent Inhibitor of Polymerization Not pertinent. 

Domb, A., and Langer, R., Solid state and solution stability... 

Call external program alkaline solution stability.exe Assign value2 to SAMPLE/ alkaline solution stability Send message to SOLVENT/procedure start = value2... 

Send message to SAMPLE activate procedure find alkaline solution stability ... 

An electrophoretic method was described by Srivastava et al. [40] to study equilibria of the cited mixed ligand complex systems in solution. Stability constants of the Zn(II) and Cd(II) complexes were 5.36 and 5.18 (log K values), respectively, at an ionic strength of 0.1 and a temperature of 35 °C. 

In solution, stabilization due to polarizability is of less importance, as the solvent will provide other charge stabilization mechanisms. However, recent work shows that polarizability is still of influence in solution 57,58,59). 

Good solubility and solution stability in a suitable solvent for spin coating ... 

Solution Composition Effect of Solution Stability, Deposition Kinetics, and Deposit... 

In contrast to a mixture of redox couples that rapidly reach thermodynamic equilibrium because of fast reaction kinetics, e.g., a mixture of Fe2+/Fe3+ and Ce3+/ Ce4+, due to the slow kinetics of the electroless reaction, the two (sometimes more) couples in a standard electroless solution are not in equilibrium. Nonequilibrium systems of the latter kind were known in the past as polyelectrode systems [18, 19]. Electroless solutions are by their nature thermodyamically prone to reaction between the metal ions and reductant, which is facilitated by a heterogeneous catalyst. In properly formulated electroless solutions, metal ions are complexed, a buffer maintains solution pH, and solution stabilizers, which are normally catalytic poisons, are often employed. The latter adsorb on extraneous catalytically active sites, whether particles in solution, or sites on mechanical components of the deposition system/ container, to inhibit deposition reactions. With proper maintenance, electroless solutions may operate for periods of months at elevated temperatures, and exhibit minimal extraneous metal deposition. 

Since electroless deposition involves complexants, reducing agents, and solution stabilizers, all of which adsorb to some degree or another on the deposit surface, it is unreasonable to not expect incorporation of minute amounts of elements such as C, or S from a S containing additive, in the deposit. 

Oxygen gas is normally present in electroless solutions unless steps are taken to reduce its concentration by inert gas purging, the concentration of dissolved O2 usually approaches 10 4 mol dm 3 at room temperature. In contrast to deliberately added solution stabilizers, the O2 molecule tends to adsorb weakly on catalytically active surfaces, where it may or may not undergo dissociation [125], Since at many metallic surfaces it is capable of being reduced via either a 2-electron or a 4-electron reaction route, dissolved O2 gas affects the mixed potential of the surface being coated in the electroless solution. Shown here is the case of a 4-electron reduction reaction in basic solution ... 

Most often in these processes, compounds such as acetic acid, acetylacetone (acac, 2,4-pentanedione), or amine compounds are employed, since these compounds readily react with alkoxides.4M877 A typical reaction involves the formation of new chemical species that (hopefully) possess physical and chemical characteristics that are more attractive in terms of solution stability and film formation behavior. An example reaction between a metal alkoxide and acetic acid is shown below ... 

A typical flowchart for a chelate process is shown in Fig. 2.6.46 In this process, titanium isoproproxide is first added to zirconium butoxide. Acetic acid is then added to the precursor mixture for suppression of hydrolysis. Finally, lead acetate is then added to the solution, followed by the addition of alcohol and water for control of solution viscosity, solution stability, and oligomer formation.46... 

The temperature at which separations are performed is another variable that can markedly affect separations. Temperatures up to 50 or 60°C often result in improved separations due to decreased viscosity and better mass transfer. Solute stability at these elevated temperatures should be determined prior to use. 

---