Sodium carbonate 608 INDEX

The precursors of the carbazoles are the anthrimides, in particular the 1,1 -dianthraquinonylamines (l,T-dianthrimides). These intermediates were originally used as vat dyes themselves, but very few give bright colours and the vatting process also brings about reduction to 1-aminoanthraquinone. Only one dianthrimide is currently active in the Colour Index [11] this grey vat dye is Cl Vat Black 28 (6.83). l,l -Dianthrimides are easily prepared by heating a 1-aminoanthraquinone with a 1-chloroanthraquinone in nitrobenzene or another solvent in the presence of sodium carbonate and a copper catalyst. 

The Surlyn A ionomers (E. I. du Pont de Nemours Co.) are believed to be derived from copolymers of ethylene with minor amounts of methacrylic acid which are treated subsequently, so that substantial amounts of the carboxylic acid are converted to the sodium or other metal carboxylate. Resins similar to the one studied in this work contain about 10 weight % methacrylic acid. The ash (sodium carbonate) indicates about 40% neutralization. This resin, which contains 0.05% Santo-white Powder (Monsanto Chemical Co.), a phenolic antioxidant, is of medium molecular weight—i.e., probably corresponding to an ethylene homopolymer with a melt flow index around 20 (17). The molecular weight distribution is broad (17). 

Incidents of several different types have arisen from reactions involving neutralisation of an acid with a base where the exotherm (57.3 kJ/equivalent for strong acid—strong base reactions) has not occurred smoothly over an extended period, but has been sudden in effect for various reasons. Individually indexed neutralisation incidents are f Formaldehyde, Magnesium carbonate hydroxide, 0415 Potassium hydroxide, Acids, 4422 Sodium carbonate, 0549 Sulfuric acid, 4-Methylpyridine, 4473 Sulfuric acid, Diethylamine, 4473 2,4,6-Trichloro-l,3,5-triazine, 2-Ethoxyethanol, 1035 See related UNIT process or unit operation incidents... 

Antioxidant activity of silica nanocomposites with immobilized vitamin C was tested using the polyphenolic activity index.8 After adsorption of ascorbic acid on the silica surface and centrifugation, the excess solution was removed to obtain the suspension of a fixed volume (2 ml). Distilled water, sodium carbonate solution, and Folin-Ciocalteu s phenol reagent were subsequently added to suspensions and to the reference Vitamin C solution. The suspensions were then stored for 30 min, and the optical density of supernatant was measured at X = 750 nm. The reference solution of ascorbic acid was used to compare antioxidant activity of vitamin-containing nanocomposites with the activity of dissolved vitamin C. 

The experimental details of the swelling treatment are as follows 1500 ml. of acid of the required concentration were made up by weighing. The acid was cooled to 2°C. and 60 grams of air-dried cotton stirred in. After thorough mixing the cotton and acid were allowed to stand for one hour in an ice-water bath and the mixture was then poured into 10 liters of water at 2°C. The cellulose was filtered off, washed repeatedly with water, then with 1% sodium carbonate solution and finally with water until washings had the same refractive index as distilled water. The cellulose was drained free of water and stored moist at 5°C. until required. 

Another interesting phenomenon was discovered in the 1960s by Brouns, Visser, and De Wolff, who studied the room-temperature phase of sodium carbonate. After many efforts, they were unsuccessful in indexing the lines of the... 

Listed by the Colour Index (1971 Cl 77122/Pigment White 23) where it is described as a co-precipitate of approximately 25% aluminium hydroxide and 75% barium sulfate qq.v.). Prepared by co-precipitation from sodium carbonate, aluminium sulfate and barium chloride. 

The first of these, Al2(S04)3, is commercially supplied as the octadecahydrate, though it typically contains 5-10% less water frian it theoretically should Merck Index, 1996). Patton (1973i) also lists hght almnina hydrate as a basic almninium sidfate prepared as a precipitate from solutions of aluminium sidfate and sodium carbonate he adds friat no precise formula exists... 

Barilun carbonate (BaC03) occurs naturally as the mineral witherite (q.v.). Synthesis is by precipitation (for example, the reaction of bariiun sulfate and sodium carbonate or carbon dioxide) a fuller description is given in, for example, the Colour Index (see Cl 77099/CI Pigment white 10). 

According to the Colour Index (1971), synthetic calcite can be produced industrially in two ways (1) from conversion of calcium oxide, and (2) as a precipitate of calcium chloride with sodium carbonate. The resultant compound was often used as a base for lake pigments and as an extender for others. However, see calcium carbonates group for a fuller discussion of synthesis. The Colour Index designation for this pigment is Cl 77220/Pigment White 18. The term whiting also may refer to a synthetic calcimn carbonate. 

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