Nickel recrystallization temperature

Isoallospirostane-3, 11-dione (0.3 g) is hydrogenated in 50 ml of ethanol at room temperature and atmospheric pressure over a small spoonful (about 1 g) of prereduced W4 Raney nickel. After filtration and evaporation the residue is recrystallized to give an 80-85% yield of the 3yS-hydroxyl-ll-one. ... 

In a hydrogenation autoclave are introduced 92 g of 2-hydroxy-4-nitrophenylbenzoate preceded by 200 cc of ethyl acetate Raney nickel, obtained from 30 g of alloy, is added with 300 cc of ethyl acetate. Hydrogenation under pressure (100 to 120 kg) at ordinary temperature is carried out during a period of about 12 hours. The nickel is filtered off and the ethyl acetate is removed by distillation on the water bath under a vacuum of 300 mm. There is thus obtained 80 g of crude damp 2-hydroxy-4-aminophenylbenzoate which after recrystallization from isopropyl alcohol melts at 153°C. 

To a stirred solution of 45g 3,5-dimethoxybenzoyl chloride and 17.4g thiophen in 300 ml benzene at 0° C, add dropwise 10.5g freshly distilled stannic chloride. Stir one hour at room temperature and add 200 ml 3% aqueous HC1. Separate the benzene layer and wash the aqueous layer with benzene. Dry and evaporate in vacuum the combined benzene layers and distill the red residue (250° C bath/4.5) to get 45g 2-(3,5-dimethoxybenzoyl) thiophen(I). Recrystallize from petroleum ether. Add a solution of 21 g AICI3 in 160 ml ether to a stirred suspension of 6.1 g lithium aluminum hydride in 140 ml ether. After 5 minutes add a solution of 39g(I) in 300 ml ether at a rate giving a gentle reflux. Reflux and stir 1 hour cool in an ice bath and treat dropwise with 50 ml water, then 50 ml 6N aqueous sulfuric acid. Separate the layers, extract the aqueous layer with 3X100 ml ether and dry, evaporate in vacuum the combined ether layers. Can distill the residue (230° C bath/5mm) to get 27g oily 2-(3,5-dimethoxybenzyl) thiophen (II). Recrystallize from petroleum ether. Reflux a solution of 5g (II) in 700 ml ethanol with W-7 Raney Nickel prepared from Ni-Al alloy (see Org. Synthesis Coll. Vol 111,176(1955)) for 6 hours. Filter, evaporate in vacuum and can distill (140/0.01) to get about 2.2g oily olivetol dimethyl ether which can be reduced to olivetol as described elsewhere here. -... 

Treatment of a benzene solution of VI with an excess of nickel chloride in methanol resulted in the precipitation of a yellow powder. This was recrystallized from methanol to give air-stable yellow-orange crystals (60%) with the stoichiometry (VI) NiCl2 -3MeOH (by combustion analysis). When this recrystallized complex was treated with excess aqueous sodium cyanide in the presence of CgDg at room temperature for 10 min VI was regenerated, but now the 3 3P NMR absorptions at 6 -58.1 and -64.0 ppm were in an area ratio of 95 5. Similar treatment of VII with nickel chloride led to a dark oily precipitate which required considerable manipulation to partially purify it. Treatment with sodium cyanide as above led to the regeneration of VII also enriched in the major isomer (85 15). 

Dichlorobis(triisopropylphosphine)nickel is first prepared by the following procedure, which is similar to the original synthesis of Giacometti and Turco.8 Triisopropylphosphine (8.0 g, 0.050 mol) is added slowly to a solution of nickel dichloride hexahydrate (5.9 g, 0.025 mol) in ethanol (100 mL) at room temperature in a nitrogen or argon atmosphere. A red, crystalline precipitate deposits immediately. After the addition is complete, the mixture is left for 5 hr and the product is filtered off, washed with ethanol, and dried in vacuo. (Yield 9.6 g, 85 %.) The compound can be recrystallized by dissolving it in hot benzene (10 g in 250 mL) and by adding n-hexane (500 mL). 

The Step 1 product (6.19 mmol) dissolved in 200 ml methyl alcohol was hydrogenated 60 minutes at ambient temperature using Raney nickel (400 mg), then filtered, and concentrated. The residue was purified by recrystallization using CH2Cl2/hexane and the product isolated as a colorless crystalline solid, mp = 160—161°C. 

Transfer the solution obtained in Sec. A after reduction with sodium tetrahy-droborate (but before addition of perchloric acid) to a 1-1. single-necked flask with 29 g (0.6 mole) of sodium cyanide. Fit the flask with a condenser and reflux the solution for 2 hr. Cool the solution to room temperature, add 15 g of sodium hydroxide, and evaporate on a rotary evaporator until a semisolid remains. Chloroform, 100 ml, is added to the flask, and the mixture is transferred to a large frit. The liquid is drawn off, and the solid is washed twice with 100-ml portions of chloroform. The aqueous layer is then separated from the filtrate and washed five to seven times with 50-ml portions of chloroform. All the chloroform extracts are dried over sodium sulfate and then evaporated to dryness. The yellowish solid is recrystallized from 800 ml of chlorobenzene to yield white needles which are collected by suction and washed with 50 ml of ethyl ether. The product is then air-dried. A second crop obtained by evaporating the filtrate is treated similarly. Yield 19 g or 63%. Anal. Calcd. for CioH24N4 C, 59.99 H, 12.09 N, 28.01. Found C, 60.1 H, 11.8 N, 28.2. Alternatively, the free base may be recovered from the isolated nickel complex by the above procedure. 

The other technique is to use a rolling and recrystaUization texture. Nickel is normally used in this method, since the heat resistance of ifickel is good and the 100 <001> texture is easily obtained. A nickel ingot is rolled with a reduction ratio of more than 90%, then the rolled nickel tape is annealed in an inert atmosphere at a temperature near 1000°C for recrystaUization. After recrystallization, nickel crystals align biaxially, and 100 <001> texture was achieved. A Ce02 buffer layer is deposited heteroepitaxially on the textured nickel in order to prevent a chemical... 

To a solution containing the dithiane (0.6 g, 1.5 mmol) in absolute ethanol (100 inL) was added Raney nickel (2 g). The suspension was heated at reflux for 4 h, cooled to room temperature, and filtered through Celite with ethanol (200 mL). The solid was recrystallized from EtOAc to give 0.46 g (93%) of the reduced product as a white solid. 

Dichlorobis(trimethylphosphine)nickel(lI) (1.0 g, 3.5 mmol) is placed in a 50 mL Schlenk tube and the flask is then filled with nitrogen. THF (20 mL) is added, and the mixture is stirred magnetically at -70 C. A solution of MeLi in Et20 (6 M, 12 mL) is added by syringe, and the system is allowed to warm to 0 °C. The solvent is removed by pumping at the same temperature, and the residue is extracted with cold pentane. The extract is gradually concentrated under reduced pressure to give yellow needles of the title compound (82%). Further purification may be performed by recrystallization from Et O. 

Succinic acid In an autoclave (325 ml capacity), 58 g of maleic acid, dissolved in 100 ml of water containing 5 g of sodium hydroxide more than needed for neutralization, were treated with 5-8 g of Raney nickel.215 Hydrogen was added to a pressure of 170 atm and heating then commenced. The pressure at first rose, but it decreased as reaction began (at 100°). This temperature of 100° was maintained until the end of the reaction after 26 min there was no further fall in pressure. After removal of the catalyst (care pyrophoric ), the mixture was acidified and the water removed in a vacuum. The succinic acid was extracted with absolute ethanol and the ethanol was then evaporated. 57 g (98%) of succinic acid were obtained when recrystallized from water it melted at 184-185°. 

Only if absolutely free from sulfur can aromatic compounds be hydrogenated with platinum metals at low temperatures. Willstatter and Hatt217 hydrogenated twelve times recrystallized naphthalene in glacial acetic acid quantitatively to decalin in presence of platinum black at room temperature and atmospheric pressure. Schroeter218 hydrogenated naphthalene to decalin in precence of nickel catalysts at 40 atm and about 200°, and to tetralin at 15 atm and about 200° ... 

Condensation of diethyl butyl malonate and />-benzyloxyhydrazo-benzene is done in the presence of sodium ethoxide in anhydrous ethanol to yield l-(benzyloxy)-2-phenyl-4-butyl-3, 5-pyrazolidinedione. The reaction mixture is heated with xylene to about 140°C for several hours which aids in the removal ethanol eliminated by cyclization. The resulting product is debenzylated by the aid of Raney Nickel hydrogenation at an ambient temperature and pressure. The crude product may be recrystallized from ether/petroleum ether. 

Another method for preparing BaO is based on careful dehydration of Ba(OH)a SHgO, which has been repeatedly recrystallized before use. The mass is then heated for two hours at 800°C in a stream of dry Ng or Hg, free of Og and COg. Melting of the Ba(OH)a cannot be avoided since the temperature reaches 700°C hence, it is advisable to use vessels made of sintered corimdum or pure nickel. Other materials such as Pt, stainless steel, quartz, porcelain, etc., are corroded. 

A nickel boat s (Fig. 269), lined with pure sodium azide. Is charged with a finely powdered mixture of NaNOa (purified by recrystallization and dried at 200°C) and about 5.5 times (by weight) as much NaNa. The boat is placed in a Pyrex tube a and slowly heated by means of an electric furnace to 200°C in vacuum (Hg diffusion pump). When the reagents have thus been freed of moisture, the temperature is slowly raised to 270-290°C. (An explosion may occur on too rapid heating). The azide decomposes, imparting a dark gray color to the salt mixture. The stopcock... 

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