Recrystallization, active materials

The active material is produced by dissolutimi of pure iron in sulfuric acid. The FeS04 is recrystallized, dried, and roasted at high temperature to produce Fc203. The materials are washed free of the sulfate, dried, and partiaUy reduced in H2 to produce a mixture of Fe304 and iron. The resulting mixture is blended with small amounts of FeS, sulfur, and HgO for use in negative plate assembly. 

The nickel-iron battery cell fabrication process is essentially unchanged in over 50 years. Special attention must be paid to use high purity materials and particle size characteristics of the active materials. The iron negative active material is made from pure iron that is dissolved in sulfuric acid. The resulting Fe(S04>2 is recrystallized and dried. This is washed free of sulfuric acid and roasted at 915°C to form a mixture of FeaOs and Fe metal and is, then, blended with small amotmts of FeS, sulfur, and HgO for use in the negative plate assembly. 

The difference between sintered plate cells and pocket-type cells with regard to memory may be connected with the fact that pocket cadmium active material contains an addition of finely divided iron compounds. This addition is made to prolong life by preventing recrystallization and agglomeration of cadmium particles. It seems probable that the iron addition will not only prevent the normal tendency for crystal growth of the cadmium material, but will also eliminate the particle size redistribution that causes the memory effect. 

Hydroxyandrosta-4,6-dien-3-one. A suspension of 42 g of crude androsta-4,6-diene-3j ,17j -diol in 2000 ml of chloroform is treated with 250 g of activated, manganese dioxide. The mixture is then shaken vigorously for 15 min in a stoppered flask. The mixture is filtered and the manganese dioxide washed well with chloroform in order to elute material which initially remains adsorbed on the solid phase. The filtrate is concentrated to a pale yellow, crystalline residue. Recrystallization from acetonitrile gives 38 g (90%) of 17/ -hydroxyandrosta-4,6-dien-3-one as plates mp 211-214°. 

A mixture consisting of 0.69 g (10.5 mmoles) of zinc-copper couple, 12 ml of dry ether, and a small crystal of iodine, is stirred with a magnetic stirrer and 2.34 g (0.7 ml, 8.75 mmoles) of methylene iodide is added. The mixture is warmed with an infrared lamp to initiate the reaction which is allowed to proceed for 30 min in a water bath at 35°. A solution of 0.97 g (2.5 mmoles) of cholest-4-en-3/ -ol in 7 ml of dry ether is added over a period of 20 min, and the mixture is stirred for an additional hr at 40°. The reaction mixture is cooled with an ice bath and diluted with a saturated solution of magnesium chloride. The supernatant is decanted from the precipitate, and the precipitate is washed twice with ether. The combined ether extracts are washed with saturated sodium chloride solution and dried over anhydrous sodium sulfate. The solvent is removed under reduced pressure and the residue is chromatographed immediately on 50 g of alumina (activity III). Elution with benzene gives 0.62 g (62%) of crystalline 4/5,5/5-methylene-5 -cholestan-3/5-ol. Recrystallization from acetone gives material of mp 94-95° Hd -10°. 

Meyers has also reported the use of chiral oxazolines in asymmetric copper-catalyzed Ullmann coupling reactions. For example, treatment of bromooxazoline 50 with activated copper powder in refluxing DMF afforded binaphthyl oxazoline 51 as a 93 7 mixture of atropisomers diastereomerically pure material was obtained in 57% yield after a single recrystallization. Reductive cleavage of the oxazoline groups as described above afforded diol 52 in 88% yield. This methodology has also been applied to the synthesis of biaryl derivatives. 

Aj Preparation of 3-Chloromethyl-6-Chloro-7-Sulfamyl-3,4-Dihydro-Benzothiadizine-1,1-Dioxide—Jo 8 ml of 40-50% chloroacetaldehyde aqueous solution and 7 ml of dimethyl-formamide are added 10 grams of 2,4-disulfamvl-5-chloroaniline. The mixture is heated on a steam bath for 2 hours after which it Is concentrated at reduced pressure. The residue Is triturated with water. The solid material is recrystallized from methanol-ether after-treatment with activated carbon to give 7.2 grams of product, MP 229°-230°C. 

The material was purified by recrystallization from ethanol with the addition of activated carbon. In this manner 24.2 g 1,3-dimethyl-4-[7-[4-(o-methoxyphenyl]-piperizinyl-(1)] pro-pylamino] -uracil having a melting point of 10O C were obtained corresponding to a yield of 75%. The purification may also be effected by boiling the material in acetone to result in similar yields. 

B. 2-Methylcyclopenlane-l,3,5-trione hydrate. A mixture of 200 g. (0.89 mole) of the keto ester prepared above, 910 ml. of water, and 100 ml. of 85% phosphoric acid is healed under reflux for 4 hours and then cooled in an ice-salt bath to —5°. The trione mixed with oxalic acid separates and is collected by filtration and dried under reduced pressure. The dried material is extracted with boiling ether (250-300 ml.) under reflux, and the ethereal extract is separated from the undissolved oxalic acid. The original aqueous filtrate is also extracted with ether in a continuous extractor. The two extracts are combined, and ether is removed by distillation. The crude trione separates as a dark brown solid and is crystallized from ca. 250 ml. of hot water. The once-crystallized, faintly yellow product weighs 95-105 g. (74-82%), m.p. 70-74°. This product is used in the next step without further purification. A better specimen, m.p. 77-78°, which is almost colorless, can be obtained by recrystallization from hot water after treatment with Norit activated carbon. 

The submitters reported a melting point of 114-116°. The checkers obtained analytically pure material with a recovery of 80% after decolorization with activated carbon and recrystallization from 2-3 ml. of hexane at 0°. The product was also purified with comparable efficiency by sublimation at 85-90° (10 mm.). A small amount of a yellow, volatile impurity was removed from the cold finger before the product began to sublime. The melting point of the product after purification by the checkers was 110-112°. The reported melting point is 114-116°. 

Recrystallization procedure applied to the amorphous aluminosilicates of different chemical composition resulted in the formation of the dispersed zeolitic domains of the FAU and BEA structure in porous matrices. The structural transformation into the composite material was proved with TEM, XRD and 27Al and 29Si MAS NMR spectroscopies. The IR data revealed that strong Bronsted acid centers were main active sites generated in the composite materials, irrespectively of the Al content. 

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