Nitrogen, drying with phosphorus pentoxide

Tank nitrogen was dried with phosphorus pentoxide. 

Rice and Getz J made a very complete study of the matter from this point of view. At 65° C. they found k = 0-286, compared with the value 0-292 of Daniels and Johnston. In order to test the possibility that the reaction might depend on catalysis by dust, they compared the velocity constants for filtered and unfiltered nitrogen pentoxide and for gas which had been passed through an electrical dust precipitator. In some experiments the gas was dried with phosphorus pentoxide, in others not. In some it was prepared by the dehydration of nitric acid with phosphorus pentoxide and in others by the action of chlorine on silver nitrate. Nitric acid was found to have no catalytic effect on the decomposition. Some of the principal results are summarized below, all data referring to 65° C. 

Bis[triphenylphosphanc] bis-[2-thiopheneteUuroIato]dlpalladium3 Under nitrogen, 1.15 g (1 mmol) of tctrakis[triphenylphosphane]palladium are dissolved in 50 ml of anhydrous benzene, a benzene solution of 0.42 g (1 mmol) of bis[2-thicnyl] ditellurium is added, the mixture is stirred under nitrogen overnight, and then filtered. The brown solid is washed with diethyl ether and dried over phosphorus pentoxide under vacuum. Addition of hexane to the filtrate precipitated additional product. 

Styrene (99% pure) was obtained from Fisher Scientific and Aldrich Chemicd. It was used either as supplied or after purification to remove the inhibitor. To remove the inhibitor, styrene (Aldrich) was washed three time with 10% sodium hydroxide and dried over phosphorus pentoxide in a desiccator after repeated washing with water. The purified sample was stored under nitrogen at 0<>C. Potassium persulfate and AIBN initiators were obtained from Fisher and DuPont, respectively, and were used without further purification. Sodium... 

S g. (0.84 g. atom) of zinc dust, and 52.5 g. (0.46 mole) of 3-methylpentane-2,4-dione (Note 1). The contents of the flask are stirred vigorously (Note 2), and a solution of 42 g. (0.415 mole) of diacetyl monoxime in 150 ml. of glacial acetic acid is added from a separatory funnel at a rate to maintain the temperature of the mixture at 65-70°. The addition takes 1 hour. When the addition is complete, the mixture is refluxed with stirring for an additional 30 minutes. The flask is then fitted for distillation with steam under nitrogen 500 ml. of water is added and steam is introduced. Steam distillation (Note 3) is continued until no more tetramethylpyrrole comes over. This takes 1-2 hours and the distillate amounts to 1-2 1. The tetramethylpyrrole crystallizes from the steam distillate and is collected by filtration, washed with water, and dried over phosphorus pentoxide in a vacuum desiccator. There is obtained 15-18 g. of white plates, m.p. 110-111° (lit., m.p. 112°). 

Tetranitrogen tetrasulfide is prepared by the method of Villena-Blanco and Jolly" and is recrystallized from toluene before use. Diphenylphosphinous chloride (Aldrich) is used as received. Acetonitrile is dried over phosphorus pentoxide and then calcium hydride, and distilled from CaH2 when needed. The reaction is carried out in an oven-dried one-necked 100-mL flask fitted with a side arm and under an atmosphere of dry nitrogen, which is also used for the work-up procedure. 

In dim red light, the weighed hydrazide contained in one of the 500 ml flasks (ca. 67 g 95% of theory) is washed into a 1000 ml beaker with 263 ml IN hydrochloric acid. 239 ml distilled water, 239 ml ethanol (95%), and 37 ml 2,4-pentanedione are added, and the well-mixed solution left to stand in the dark at room temperature until the reaction is complete, i.e., about 30 minutes. The reaction mixture is neutralized with the addition of 263 ml 1 N sodium hydroxide, and the beaker covered with parafilm and refrigerated to ensure complete precipitation. The pyrazole is filtered at the pump, the mother liquor being returned to the beaker and used to wash out the last few crystals, washed with cold water, and sucked dry under a stream of dry nitrogen. The product is dried in vacuo over barium oxide or phosphorus pentoxide for at least twelve hours before proceeding to the next step, wherein anhydrous conditions will increase yield. Hofmann calls for drying the pyrazole in vacuo at 60°, which indicated the product to be fairly stable. So all the hydrazide is converted prior to aminization. 

A. 3-Methyl-3-(toluenesulfonyloxymethyl)oxetane [Oxetane tosylate, ( )]. A dry, 1-L, round-bottomed flask is charged with a-toluenesulfonyl chloride (57.20 g, 0.30 mol) (Note 1) to which pyridine (250 mL) (Note 2) is added while stirring is carried out under nitrogen with a magnetic stir bar (Note 3). The reaction flask is placed inside a container to which an ice/water mixture may be added in the event that the reaction becomes too exothermic. 3-Methyl-3-oxetanemethanol (20.4 g, 0.2 mol) (Note 4) is added slowly and stirred for 1.5 hr. The mixture is slowly added to a vigorously (Note 3) stirred mixture of deionized water (700 mL) and crushed ice (700 g) in a 2-L Erlenmeyer flask and allowed to stir for ein additional 0.5 hr. The white precipitate is collected on Whatman filter paper 1 and washed with cold water (HjO, Note 5). The product is dried under high vacuum and/or phosphorus pentoxide (P2O5) to obtain the white powder of oxetane tosylate 1 (39.8-44.60 g, 78-87%) (Note 6). 

Solid ammonium nitrate is very deliquescent in moist air, and it is very soluble in water. According to H. Lescceur10 and F. L. Kortright, at 20°, the salt absorbs moisture from the air if the vap. press, of the water is over 9 mm. The vap. press, of a sat. soln. has the same value. It is very difficult to dry the salt it can be obtained with less than 0 1 per cent, of moisture by exposure over phosphorus pentoxide at ordinary temp, in a desiccator. U. Behn observed a slight decomposition of the salt after it had stood a few days in the desiccator. This was evidenced by the smell of nitrogen oxides. If heated, the decomposition is quicker. If one limb of a U-tube containing the salt be heated to 100°, and the other limb be cooled to —79°, water is continuously collected, but the salt becomes no drier. 

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