Calcium salt systems

Hydrolysis of Peroxycarboxylic Systems. Peroxyacetic acid [79-21-0] is produced commercially by the controlled autoxidation of acetaldehyde (qv). Under hydrolytic conditions, it forms an equiHbrium mixture with acetic acid and hydrogen peroxide. The hydrogen peroxide can be recovered from the mixture by extractive distillation (89) or by precipitating as the calcium salt followed by carbonating with carbon dioxide. These methods are not practiced on a commercial scale. Alternatively, the peroxycarboxyHc acid and alcohols can be treated with an estetifying catalyst to form H2O2 and the corresponding ester (90,91) (see Peroxides and peroxy compounds). 

BeryUium reacts with fused alkaU haUdes releasing the alkaU metal until an equUibrium is estabUshed. It does not react with fused haUdes of the alkaline-earth metals to release the alkaline-earth metal. Water-insoluble fluoroberyUates, however, are formed in a fused-salt system whenever barium or calcium fluoride is present. BeryUium reduces haUdes of aluminum and heavier elements. Alkaline-earth metals can be used effectively to reduce beryUium from its haUdes, but the use of alkaline-earths other than magnesium [7439-95-4] is economically unattractive because of the formation of water-insoluble fluoroberyUates. Formation of these fluorides precludes efficient recovery of the unreduced beryUium from the reaction products in subsequent processing operations. 

Calcium ion enters the system not ordy in the form of water hardness but also in the form of calcium salts contained in the sod. Other heavy-metal ions such as aluminum and ferric iron may also be present in the sod, and must be removed by an appropriate budder to achieve good sod removal. Effective budders for cotton washing are those for which the calcium dissociation constant, expressed as or —logif -, is >4 and preferably >7 (33). 

The Immobili dEn me System. The glucose isomerases used are immobilized and granulated to a particle size between 0.3 and 1.0 mm. The enzyme granulates must be rigid enough to withstand compaction when they are packed iato the column. Ca " acts as an inhibitor in the system, and therefore calcium salts need to be removed from the feed symp. Conversely, Mg " acts as an activator, and magnesium salts are added to the feed symp. 

A biopolymer produced by a particular strain of bacteria is becoming widely used as a substitute for clay in low-solids muds. Since the polymer is attacked readily by bacteria, a bactericide such as paraformaldehyde or a chlorinated phenol also must be used with the biopolymer. The system has more stable properties than the extended bentonite system, because biopolymer exhibits good rheological properties in its own right, and has a better tolerance to salt and calcium. The system can be formulated to include salt, such as potassium chloride. Such a system, however, would then be classed as a nondispersed inhibitive fluid. 

A reaction of practical importance is the oxidation of a carbohydrate aldehyde group to a carboxyl group. This is the basis for a process converting glucose to calcium gluconate, a substance of pharmaceutical interest. The oxidation reaction occurs at graphite electrodes in the presence of the Brj/Br" redox system. Calcium salt is added to the solution to prevent further oxidation of free gluconic acid. 

The bone becomes depleted of calcium salts when the urine is acidic over a relatively long period. This was shown by Goto (17) who fed rabbits large doses of hydrochloric acid. He then showed that urinary calcium loss occurred in concert with a marked reduction in mass of the skeletal system, and also that the total non-fat dry weight of bone decreased,implying a loss of bone matrix. A dose-dependent, dietary acid induced loss of labelled calcium from rat bone has been reported by Thorn and his coworkers (18). They demonstrated that in response to graded doses of ascorbic acid, cells in tissue culture, and bones in whole animals fed such doses were depleted of the labelled calcium. 

The saponified fatty acids which are used are most often palmitic, stearic or oleic acid but the way in which they confer a hydrophobic nature to the surface of the ink particle is not well understood. If enough calcium ions are present (and these sometimes need to be added to the system) insoluble calcium salts of the fatty acids are probably produced and these may coat the surface of the print particle making it hydrophobic. The ink particle then adheres to an air bubble and can be floated out of the stock. The saponified fatty acids are often called collectors —a term which comes from mineral flotation. 

P.R.48 2 is less commonly found in paints. In paints, like in other areas of application, the calcium salt performs like the barium lake. Both are, for instance, equally fast to overcoating. The list of suitable application areas for both pigments is the same. P.R.48 2 is also used in oven drying paints, nitro paints, and in similar systems. Besides, it is also found in emulsion paints. While barium and calcium salts exhibit equal lightfastness in full shades, there is a considerable difference in white reductions. Increasing amounts of Ti02 render P.R.48 2 much more sensitive to light than P.R.48 . 

ChemicaPPhysical. In aqueous solutions, propazine is converted exclusively to hydroxylprop-azine (2-hydroxy-4,6-bisisopropylamino)-5 triazine by UV light (7, = 253.7 nm) (Pape and Zabik, 1970). In acidic aqueous soil-free systems, propazine hydrolysis is pH dependent and follows first-order kinetics. At 23.5 °C, the estimated hydrolysis half-lives at pH 2.0, 3.0, 4.0, and 5.0 were 9, 36, 141, and 550 d, respectively. The rate of hydrolysis also increased and decreased in the presence of organic matter and calcium salts, respectively (Nearpass, 1972). 

WARNING Systemic absorption of oral route may cause neuro/oto/nephrotox may result resp paralysis possible w/ any route of administration Uses Hepatic coma, bowel prq) Action Aminoglycoside, poorly absorbed PO -1- GI bacterial flora Dose Adults. 3-12 g/24- h PO in 3-4 doses Peds. 50-1 (X) mg/kg/24 h PO in 3-4 doses Caution [C, /-] Renal failure, neuromuscular disorders, hearing impair Contra Intestinal obst Disp Tabs, PO soln SE Hearing loss w/ long-term use rash, NA EMS Use neuromuscular blockers w/ caution, reduced dose may be necessary t bleeding risk w/ concurrent anticoagulant use OD May cause neuromuscular block and kidney failure calcium salts can be used to revise neuromuscular block... 

There are occasional anomalies to the rule that food reduces and delays peak plasma concentration. The anti-fungal drug, griseofulvin, has enhanced absorption if taken with a meal - possibly because it becomes emulsified by bile salts and passes more readily into the lymphatic drainage of the gut which bypasses the liver, entering the venous system directly. The immuno-suppressant cyclosporin, and calcium salts in general, show a similar increase in absorption when taken with a fatty meal. 

Figure 4 Calcium salt solubility in the mixed system of NaGCDC-NaGUDC as a function of pH.

Among condensed phosphate systems with polyvalent cations, the very complicated calcium salts have been much studied and a great number of compounds have been detected, often with several modifications (5, 27, 28, 34, 54, 79, 186, 137, 191, 198, 204, 211, 276, 805, 830). In this system special interest attaches to the occurrence of crystalline cross-linked phosphates (see Section V) and of calcium pentaphosphate, CayiPsOis (see Section IV,D,/). The end-product obtained by heating Ca(H2P04)2 in the free atmosphere is the high-molecular calcium polyphosphate, which crystallizes in several forms. The condensed strontium phosphates (246, 805) are similarly complicated and cannot readily be made the subject of a brief review. 

It has been known for many years that the mitochondrion shows a respiration-linked transport of a number of ions. Of these, calcium has attracted the most attention since it depends on a specific transport system with high-affinity binding sites. The uptake of calcium usually also involves a permeant anion, but in the absence of this, protons are ejected as the electron transfer system operates. The result is either the accumulation of calcium salts in the mitochondrial matrix or an alkalinization of the interior of the mitochondrion. The transfer of calcium inwards stimulates oxygen utilization but provides an alternative to the oxidative phosphorylation of ADP618 ... 

A method of prediction of the salt effect of vapor-liquid equilibrium relationships in the methanol-ethyl acetate-calcium chloride system at atmospheric pressure is described. From the determined solubilities it is assumed that methanol forms a preferential solvate of CaCl296CH OH. The preferential solvation number was calculated from the observed values of the salt effect in 14 systems, as a result of which the solvation number showed a linear relationship with respect to the concentration of solvent. With the use of the linear relation the salt effect can be determined from the solvation number of pure solvent and the vapor-liquid equilibrium relations obtained without adding a salt. 

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