Magnesium carbonate, use

Ultraviolet and Visible Spectra. All solution spectra were scanned in the visible and ultraviolet regions on a Bausch and Lomb Model 505 Spectrophotometer. Refiectance spectra were obtained with a Beckman DU Spectrophotometer equipped with the Beckman 2580 reflectance attachment. Magnesium carbonate used as a reference and diluent were... 

After purification, Mg(OH)2 can be reacted with carbon dioxide to give magnesium carbonate, used for coating sodium chloride in table salt to prevent caking and for antacid remedies. Another alternative is to add hydrochloric acid to the magnesium hydroxide to neutralize it and yield hydrated magnesium chloride ... 

If 20.0 g of carbon dioxide are produced, the number of moles of magnesium carbonate used is... 

His father was an apothecary and industrial chemist who established a profitable business manufacturing such products as magnesium carbonate (used as an antacid) and carbonated water. At the age of ten, Henry was severely injured by a falling beam and was plagued by pain and ill health for the rest of his life. 

Ethanolate and propanolate of magnesium which are dissolved in the appropriate alcohol and a nonpolar halogenated hydrocarbon can also be used as deacidification agents. By transformation of the magnesium alcoholate in the appropriate carbonates (aUcoxy magnesium carbonate) using (dry) carbon dioxide, a further improvement of the solubiHty and permanence could be reached. 

The sodium bicarbonate can be determined by the method given under Compound Powder of Magnesium Carbonate using 25 g. 

After that period, the concentration of magnesium carbonate used as a stabilizer in fine salt was increased until 2 %. This modification could improve the stabilization of iodine during our systematic study. The increase of iodine content evaluated in 1992 in the commercial salt is higher than in 1984 and this could be the explanation of the normalization of urinary excretion.With a mean content of 7.5 mg/kg we can assume that the daily supplementation would be around 25 pg of iodine per day. Those findings need to be reevaluated in other districts and moreover they raise of question of a possible regression of goiter endemicity in France which needs more epidemiological studies. 

If an excess of magnesium is used, magnesium silicide, Mg2Si, is also produced.) The silicon obtained is a light brown hygroscopic powder. Crystalline or metallic silicon is obtained industrially by the reduction of silica with carbon in an electric arc furnace ... 

When thioamides such as thiobenzamide are used directly, neither dioxane nor magnesium carbonate is necessary. Instead absolute alcohol with fused sodium acetate in the presence of piperidine is used (457). 

Processes rendered obsolete by the propylene ammoxidation process (51) include the ethylene cyanohydrin process (52—54) practiced commercially by American Cyanamid and Union Carbide in the United States and by I. G. Farben in Germany. The process involved the production of ethylene cyanohydrin by the base-cataly2ed addition of HCN to ethylene oxide in the liquid phase at about 60°C. A typical base catalyst used in this step was diethylamine. This was followed by liquid-phase or vapor-phase dehydration of the cyanohydrin. The Hquid-phase dehydration was performed at about 200°C using alkah metal or alkaline earth metal salts of organic acids, primarily formates and magnesium carbonate. Vapor-phase dehydration was accomphshed over alumina at about 250°C. 

Magnesium sulfate heptahydrate may be prepared by neutralization of sulfuric acid with magnesium carbonate or oxide, or it can be obtained directly from natural sources. It occurs abundantly as a double salt and can also be obtained from the magnesium salts that occur in brines used for the extraction of bromine (qv). The brine is treated with calcium hydroxide to precipitate magnesium hydroxide. Sulfur dioxide and air are passed through the suspension to yield magnesium sulfate (see Chemicals frombrine). Magnesium sulfate is a saline cathartic. 

Transparent white pigments (extenders) commonly used in inks, in order of decreasing transparency, ate alumina hydrate, magnesium carbonate, calcium carbonate, blanc fixe (precipitated barium sulfate), talc, and clay. Extenders ate sometimes used to reduce the color strength and change the theology of inks. 

The carbonate minerals that comprise limestone ate calcite [13397-26-7] (calcium carbonate), which is easily the most abundant mineral type aragonite [14791-73-2] (calcium carbonate) dolomite [17069-72-6] (double carbonate of calcium and magnesium) andmagnesite [13717-31 -5] (magnesium carbonate). Individual limstone types ate further described by many common names (1). Some of this nomenclature is repetitious and overlapping. The following terms ate in common use in Europe and the United States. 

USP-grade anhydrous magnesium carbonate is used as a flavor impression intensification vehicle in the processed food industry (see Flavors and spices). Basic magnesium carbonates are used as free flowing agents in the manufacture of table salt, as a hulking agent in powder and tablet pharmaceutical formulations, as an antacid, and in a variety of personal care products (see Pharmaceuticals). 

Reaction of (T)-(-)-2-acetoxysuccinyl chloride (78), prepared from (5)-mahc acid, using the magnesiobromide salt of monomethyl malonate afforded the dioxosuberate (79) which was cyclized with magnesium carbonate to a 4 1 mixture of cyclopentenone (80) and the 5-acetoxy isomer. Catalytic hydrogenation of (80) gave (81) having the thermodynamically favored aH-trans stereochemistry. Ketone reduction and hydrolysis produced the bicycHc lactone acid (82) which was converted to the Corey aldehyde equivalent (83). A number of other approaches have been described (108). 

Pyrotechnic mixtures may also contain additional components that are added to modify the bum rate, enhance the pyrotechnic effect, or serve as a binder to maintain the homogeneity of the blended mixture and provide mechanical strength when the composition is pressed or consoHdated into a tube or other container. These additional components may also function as oxidizers or fuels in the composition, and it can be anticipated that the heat output, bum rate, and ignition sensitivity may all be affected by the addition of another component to a pyrotechnic composition. An example of an additional component is the use of a catalyst, such as iron oxide, to enhance the decomposition rate of ammonium perchlorate. Diatomaceous earth or coarse sawdust may be used to slow up the bum rate of a composition, or magnesium carbonate (an acid neutralizer) may be added to help stabilize mixtures that contain an acid-sensitive component such as potassium chlorate. Binders include such materials as dextrin (partially hydrolyzed starch), various gums, and assorted polymers such as poly(vinyl alcohol), epoxies, and polyesters. Polybutadiene mbber binders are widely used as fuels and binders in the soHd propellant industry. The production of colored flames is enhanced by the presence of chlorine atoms in the pyrotechnic flame, so chlorine donors such as poly(vinyl chloride) or chlorinated mbber are often added to color-producing compositions, where they also serve as fuels. 

Magnesium sahcylate, an analgesic and antiinflammatory agent, appears to have exceptional abihty to reheve backaches. It is also used for the symptomatic rehef of arthritis. Magnesium sahcylate is prepared in a similar manner as sodium sahcylate, using the appropriate magnesium carbonate salt. 

For free-flow agents, water-insoluble, finely divided adsorbents such as sodium siUcoalurninate, tricalcium phosphate, calcium siUcate, magnesium carbonate, and siUcon dioxide are used. Concentrations between 0.5 and 2% are typically added to table salt and some industrial grades of salt for use in apphcations where caking may occur. 

Magnesium is used to obtain cesium metal from cesium hydroxide [21351 -79-17, Cs(OH), cesium carbonate [534-17-8J, or cesium... 

For electrical insulation china clay is commonly employed whilst various calcium carbonates (whiting, ground limestone, precipitated calcium carbonate, and coated calcium carbonate) are used for general purpose work. Also occasionally employed are talc, light magnesium carbonate, barytes (barium sulphate) and the silicas and silicates. For flooring applications asbestos has been an important filler. The effect of fillers on some properties of plasticised PVC are shown in Figure 12.21 (a-d). 

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