Solid stability

Chemical treatments -How organic polymers and inorganic coagulants work to counteract solids stabilization mechanisms and enhance removal of solids from water, and... 

Cyclopentadienyl)gold is a very unstable, even explosive, yellow solid stabilized by adduct formation with tertiary phosphines. 

Milk solids nonfat Cane sugar Corn sirup solids Stabilizer Emulsifier Water... 

A solids-stabilized water-in-oil emulsion may be used either as a drive fluid for displacing hydrocarbons from the formation or to produce a barrier for diverting the flow of fluids in the formation. The solid particles may be formation solid particles or nonformation solid particles, obtained from outside the formation (e.g., clays, quartz, feldspar, gypsum, coal dust, asphaltenes, polymers) [228,229]. 

A set of experiments was performed at variable droplet sizes. The graph in Fig. 4.7 shows the dependence of the normalized (by Kint/a) osmotic resistance as a function of the oil volume fraction. The normalized values fall onto a single curve within reasonable experimental uncertainty. The results were compared to the normalized data obtained by Mason et al. [7] in the presence of surfactants. These latter are represented as a solid line that corresponds to the best fit to the experimental points (Eq. (4.18)). It is worth noting that the normalized pressures in solid-stabilized emulsions are much larger than the ones obtained in the presence of surfactants. 

As explained in Section 4.2, the osmotic pressure can be expressed as a product of two independent terms, the derivative of the free energy with respect to the amount of interface a = ( f and a geometrical factor ( f representing the effect of compression (see Eq. (4.1)). Since in solid-stabilized emulsions the interfaces... 

In solid-stabilized emulsions, the droplet surface can be regarded as a compact 2-D network of solid particles with strong lateral attractive interactions. The surface... 

As reported in this chapter, the microscopic origin of both compressibility and elasticity of dense emulsions is rather well understood. Emulsions have elastic properties arising from either surface tension or surface elasticity and plasticity. Some protein-stabilized emulsions obey the same phenomenology as solid-stabilized emulsions they exhibit substantially higher osmotic resistances and higher shear moduli than surfactant-stabilized emulsions [38 0]. Moreover, they are strongly resistant to water evaporation. Proteins possess the ability to form... 

S. Arditty, C.P. Whitby, B.P. Binks, V. Schmitt, andF. Leal-Calderon SomeGeneral Features of Limited Coalescence in Solid-Stabilized Emulsions. Eur. Phys. J. E 11, 273 (2003). 

Typically, solid stabilizers utilize natural saturated fatty acid ligands with chain lengths of Cg—Clg. Zinc stearate [557-05-1], zinc neodecanoate [27253-29-8], calcium stearate [1592-23-0], barium stearate [6865-35-6], and cadmium laurate [2605-44-9] are some examples. To complete the package, the solid products also contain other solid additives such as polyols, antioxidants, and lubricants. Liquid stabilizers can make use of metal soaps of oleic acid, tall oil acids, 2-ethyl-hexanoic acid, octylphenol, and nonylphenol. Barium bis(nonylphenate) [41157-58-8], zinc 2-ethylhexanoate [136-53-8], cadmium 2-ethylhexanoate [2420-98-6], and overbased barium tallate [68855-79-8] are normally used in the liquid formulations along with solubilizers such as plasticizers, phosphites, and/or epoxidized oils. The majority of the liquid barium—cadmium formulations rely on barium nonylphenate as the source of that metal. There are even some mixed metal stabilizers supplied as pastes. The U.S. FDA approved calcium—zinc stabilizers are good examples because they contain a mixture of calcium stearate and zinc stearate suspended in epoxidized soya oil. Table 4 shows examples of typical mixed metal stabilizers. 

N. Yan and J. H. Masliyah, Characterization and demulsification of solids-stabilized oil-in-water emulsions. Part 2. Demulsification by the addition of fresh oil, Colloids Surf. 96, 243-252(1995). 

Some organic cation salts can be isolated as crystalline solids. Stability of carbenium ions is enhanced if the electron-deficient carbon is con jugated with olefin or aromatic groups or with atoms with unshared electron pairs (O, N, S). The positive charge is diflused over a larger region as a consequence. Examples of such initiators are hexachloroantimonate (SbCl ) salts of triphenyl methyl ((Cf,H5)3C ) and cyclohepirienyl (C7H ) carbenium ions. 

Tetrabenzyl pyrophosphate should be stored in a freezer as a dry solid. Stability data on TBPP are tabulated below [reported in Liquid Chromatography Area Percent (LCAP)]. The only impurity detected was dibenzyl phosphate. For this study, solid TBPP was sealed in scintillation vials with Parafilm, which were in turn enclosed in desiccators with indicating Drierite. 

Stabilizers are macro-molecules which prevent the formation of large ice crystals. The average ice crystal size should be between 40-50 pm. Stabilizers increase viscosity, improve the smoothness and resistance to melting. The average content depends on the kind of stabilizer, but it is typically between 0.01% and 0.2%. The use of stabilizers corresponds to the content of fat and solids. Stabilizers are important when the fat content is below 12% or the total content of solids is below 40%. 

Bulk drug solid stability is increasingly being achieved by improved control of crystal growth. 

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