Sodium sulfate, decomposition

Chemical Properties. Anhydrous sodium sulfite is stable in dry air at ambient temperatures or at 100°C, but in moist air it undergoes rapid oxidation to sodium sulfate [7757-82-6]. On heating to 600°C, sodium sulfite disproportionates to sodium sulfate and sodium sulfide [1313-82-2]. Above 900°C, the decomposition products are sodium oxide and sulfur dioxide. At 600°C, it forms sodium sulfide upon reduction with carbon (332). 

A number of manufacturers around the world are using the decomposition of ammonium dichromate to produce chrome oxide (eq. 5) (78). Generally, an excess of finely ground ammonium sulfate is mixed with sodium dichromate, and the dry mixture is heated to form chrome oxide and sodium sulfate, evolving nitrogen and steam. 

Benzyioxycarbonyi chioride (Cbz-Ci, benzyi cbioroformate) [501-53-1] M 170.6, b 103 /20mm, d 1.195, n 1.5190. Commercial material is better than 95% pure and may contain some toluene, benzyl alcohol, benzyl chloride and HCl. After long storage (e.g. two years at 4 , Greenstein and Winitz [The Chemistry of the Amino Acids Voi 2 p. 890, J Wiley and Sons NY, 1961] recommended that the liquid should be flushed with a stream of dry air, filtered and stored over sodium sulfate to remove CO2 and HCl which are formed by decomposition. It may further be distilled from an oil bath at a temperature below 85 because Thiel and Dent [Annalen 301 257 1898] stated that benzyioxycarbonyi chloride decarboxylates to benzyl chloride slowly at 100 and vigorously at 155 . Redistillation at higher vac below 85 yields material which shows no other peaks than those of benzyioxycarbonyi chloride by NMR spectroscopy. LACHRYMATORY and TOXIC. 

Water-soluble polymers obtained through a radical polymerization [e.g., poly(acrylic acid) PAA] often contain sodium sulfate Na2S04 as a decomposition product of the initiator. The peak of Na2S04 is eluted before the dimer. In the interpretation of the chromatogram, a typical GPC program has to be truncated before the Na2S04 peak, or at a Mpaa value of about 200. The calibration curve in this region can be flattened by an additive small pore column as well, but the principle problem remains unsolved. 

After completion of the reaction, the solvent was distilled off and the residue was extracted with dichloromethane. The extract was washed with water, dried over anhydrous sodium sulfate and the solvent was distilled off to give 3.25 g of the desired product melting at 202° to 204°C with decomposition. 

To a solution of 93.8 g of the monoglycol ester in 500 ml of benzene, there are added 55 g of nicotinic acid chloride and 25 g of trimethylemine dissolved in 200 ml of benzene. The solution is stirred gently at a temperature of 60°C for two hours. After this time, the solution is cooled and washed successively with water, dilute hydrochloric acid, dilute ammonia and water until neutrality, it is dried over anhydrous sodium sulfate, and the sol vent Is evaporated under vacuum In this wey llOg of glycol 2-(p-chlorophenoxy)-2-methylpropionate nico-tlnate Is prepared, which represents a yield of 84%. The product is a sllghly yellow oil having a refraction index of no = 1.5422 and which is distilled with decomposition et 214°C at a pressure of 0.3 mm. 

D/chloro-5-Cyclohexyl-2-Oxo-2,3-D/hydro 1 H-Benzo(fj-Diazepine-1,4 fa) Process Using Sodium Hypochlorite — 40 ml of a solution of sodium hypochlorite of 14.5 British chloro-metric degrees are added to a suspension of 5.4 grams of 7 chloro-5 cyclohexyl-2 oxo-2,3-dihydro 1 H-benzo(f)diazepine-1,4 in BO ml of methylene chloride. The mixture is stirred at room temperature for 15 minutes the solid dissolves rapidly. The organic iayer is decanted, washed with water, dried over anhydrous Sodium sulfate and the solvent evaporated under reduced pressure without exceeding a temperature of 30 C. The residue is taken up in a little diisopropyl ether and the crystals which form are dried. They are recrystallized as rapidly as possible from ethyl acetate. Colorless crystals are obtained (3.9 grams yield, B5%) MP < = 163°C, with decomposition. 

Evaporation of a chloroform solution of benzoylhydroperoxide under reduced pressure yields a paste containing 20-30 per cent of hydroperoxide. On further evaporation this decomposes into benzoic acid. A chloroform solution of benzoylhydroperoxide when carefully dried over anhydrous sodium sulfate at o° may be kept exposed to light at room temperature for a number of days without appreciable decomposition. In order to obtain benzoylhydroperoxide free from the reagents used in its preparation, it is necessary to extract the product with chloroform, such extraction resulting in a loss of about 10 per cent,... 

The carbon disulfide is decanted, and 200-300 ml. of water is added to the contents of the flask. Initially the mixture reacts slowly, but after some time the reaction becomes so vigorous that it is necessary to pour off the water (Notes 1 and 2). The addition of water, followed by its removal when the reaction becomes very vigorous, is repeated until decomposition is complete. The combined aqueous solutions are extracted several times with chloroform, and the combined extracts are dried over anhydrous sodium sulfate. Distillation of the solvent gives a dark brown liquid residue which is distilled under reduced pressure to give 310.3 g. (89%) of the thioamide as a yellow liquid, b.p. 133-135° (12 mm.) (Note 3). 

To the reaction mixture is then added an equal volume of cold water. The resultant red oil is separated by decantation, washed repeatedly with water, and finally dried with sodium sulfate. After filtration, 23 gm of product is obtained (yield 90%). No physical constants for the product have been reported, presumably because of decomposition near the boiling point. 

Reduction of Ammonium Dichromate. Chromium(III) oxide can be obtained by thermal decomposition of ammonium dichromate. Above ca. 200 °C, a highly voluminous product is formed with elimination of nitrogen [3.48]. The pigment is obtained after addition of alkali salts (e.g., sodium sulfate) and subsequent calcination [3.49]. 

The resulting solution (about 91.) is divided into two portions and each is extracted three times, 600 cc. of ether being used each time (Note 8). The combined extracts are concentrated to about 1 1. and dried overnight over 150 g. of anhydrous sodium sulfate. After filtration and evaporation of the ether, there remains 137-160 g. (58-65 per cent of the theoretical amount) of a slightly colored product, melting with decomposition at 227-229°. It is sufficiently pure for most purposes (Notes 9 and 10). 

The reason that the Na-S04-Y2(S04)2-Si02 solid electrolyte can not detect adequately the S02 gas lower than 0.1 %, is attributed to the difficulties in the formation and decomposition of sodium sulfate on the electrolyte surfaces, and in obtaining the suitable contact between the Pt net electrode and the electrolyte. 

After having been dried over sodium sulfate and evaporated under vacuum, this extract gives as a solid residue 14.7 g of crude 7-cyanoacetylamino-cephalosporanic acid which is purified by chromatography on 30 times its own weight of silica gel. The fractions eluted with chloroform plus acetone (7 3) furnish a product which crystallizes from acetone plus ether in the form of needles melting at 168° to 170°C with decomposition. 

This mixture is then diluted with water, washed with ethyl acetate, acidified with dilute sulfuric acid, and finally extracted with benzene. The benzene extract is washed with water, dried over anhydrous sodium sulfate, and evaporated to dryness at reduced pressure to produce crude 17 3-hydroxy-17a-methyl-l-oxo-l,2-seco-A-nor-5a-androstan-2-oic acid, which after recrystallization from aqueous isopropyl alcohol melts at about 166° to 173°C (decomposition). 

A solution of 1.04 g of 6-chloro-9p,10a-pregna-4,6-diene-3,20-dione and 0.95 g of 2,3-dichlorobenzoquinone in 50 ml of dry benzene was heated to reflux for 10 hours. The reaction mixture was diluted with 70 ml of benzene and extracted three times with 50 ml of 2 N sodium hydroxide solution. The benzene layer was washed with water to neutral, dried with sodium sulfate and evaporated to dryness. The residue (0.7 g) was chromatographed on 20 g Of aluminum oxide (activity II). The fraction eluted with benzene-petroleum ether were combined and recrystallized from acetone. The 6-chloro-9p,10a-pregna-l,4,6-triene-3,20-dione melted at 208-209°C(decomposition), Xmax 229 nm. 

Barium sulfate (BaS04, melting point 1580°C with decomposition) occurs as colorless rhombic crystals. It is soluble in concentrated sulfuric acid, forming an acid sulfate dilution with water reprecipitates barium sulfate. Precipitated barium sulfate, known as blancfixe, is prepared from the reaction of aqueous solutions of barium sulfide (BaS) and sodium sulfate (Na2S04). 

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