Moisture, protection from atmospheric

Phenyl isocyanate is a colourless liquid, b.p. 164° or 55°/13 mm. its vapour is lacluymatory. The liquid reacts readily with water, yielding diphenyl urea, m.p. 241°, and hence must be protected from atmospheric moisture ... 

Iodine monochlorlde may be prepared as follows. Pass dry chlorine into 127 g. of iodine contained in a 125 ml. distilling flask until the weight has increased by 34-6 g. The chlorine should be led in at or below the surface of the iodine whilst the flask is gently shaken it is essential to have an excess of iodine. Distil the iodine chloride in an ordinary distillation apparatus use a filter flask, protected from atmospheric moisture by a calcium chloride (or cotton wool) guard tube, as a receiver. Collect the fraction b.p. 97-105° the jdeld is 140 g. Preserve the iodine monochloride in a dry, glass-stoppered bottle. 

Subsequent dehydrohalogenation afforded exclusively the desired (Z)-olefin of the PGI2 methyl ester. Conversion to the sodium salt was achieved by treatment with sodium hydroxide. The sodium salt is crystalline and, when protected from atmospheric moisture and carbon dioxide, is indefinitely stable. A variation of this synthesis started with a C-5 acetylenic PGF derivative and used a mercury salt cataly2ed cyclization reaction (219). Although natural PGI has not been identified, the syntheses of both (6R)- and (65)-PGl2, [62777-90-6] and [62770-60-7], respectively, have been described, as has that of PGI3 (104,216). 

Shipment and Storage. 2-Pyrrohdinone is available in steel dmms and in aluminum or stainless-steel tank cars and tank trailers. Because of its high freezing point, bulk shipments are in tanks with heating coils. Heating with hot water rather than steam avoids product discoloration. Steel (qv), stainless steel, and aluminum are satisfactory materials for storage containers. Because 2-pyrrohdinone is hygroscopic, it must be protected from atmospheric moisture. 

Shipment, Stora.ge, ndPrice. l-Methyl-2-pyrrohdinone is available in tank cars or tank trailers as well as in dmms. Shipping containers are normally of unlined steel. Rubber hose is unsuitable for handling standard steel pipe or braided steel hose is acceptable. Ordinarily 1020 carbon steel (0550) is satisfactory as a storage material. Stainless-steel 304 and 316, nickel, and aluminum are also suitable. MethylpyrroHdinone is hygroscopic and must be protected from atmospheric moisture. In September 1994, NMP was Hsted at 3.89/kg. 

Chemical Reactivity - Reactivity with Water. Reacts violently with water, liberating hydrogen chloride gas and heat Reactivity with Common Materials None if dry. If wet it attacks metals because of hydrochloric acid formed flammable hydrogen is formed Stability During Transport Stable if kept dry and protected from atmospheric moisture Neutralizing Agents for Acids and Caustics Hydrochloric acid formed by reaction with water can be flushed away with water. Rinse with sodium bicarbonate or lime solution Polymerization Not pertinent Inhibitor of Polymerization Not pertinent. 

A solution of 0.1 mol of 1-cyclohexylamino-2-propanol in 30 grams of chloroform was saturated with dry hydrogen chloride gas, with cooling. A solution of 0.1 mol of benzoyl chloride in 30 grams of chloroform was added and the solution was heated in a bath at 50° to 55°C for four days under a reflux condenser protected from atmospheric moisture. Then the solvent was removed by vacuum distillation while the mixture was warmed on a water bath. Benzene was then added to the syrupy residue and the reaction product crystal lized out after the benzene was removed by vacuum distillation. 

HPTLC plates Silica gel 60 F254 (Merck) before the samples were applied these were immersed for 4 h in 2-propanol and then dried for 30 min at 110 °C. After cooling in the desiccator the layers were protected from atmospheric moisture by covering them 1 cm above the start zones with a glass plate. 

Benzene is conveniently dried by slowly distilling about 20% of it and cooling the residue with protection from atmospheric moisture by use of a calcium chloride tube. 

The equipment is dried and protected from atmospheric moisture by calcium chloride tubes. 

These effects undoubtedly increase thermal stability of SENAs (many of these compounds are distilled in vacuo at temperatures higher than 100°C, see Table 3.7). At the same time, SENAs are hydrolytically highly unstable (see Section 3.4.2.2.). Besides, these compounds can undergo spontaneous decomposition for unknown reasons. It is known that acidic impurities facilitate these processes, whereas triethylamine, on the contrary, stabilizes SENAs (191). Hence, SENAs are recommended to be either stored in a refrigerator with full protection from atmospheric moisture or used in situ. 

A 1-1., four-necked, round-bottomed flask equipped with reflux condenser, sealed stirrer, thermometer, and solid addition funnel and protected from atmospheric moisture with a Drierite guard tube is carefully dried and flushed with a dry inert gas (Note I). The flask is charged with 453 g. (3.1 moles) of silver difluoride (Note 2) and 500 ml. of l,l,2-trichloro-l,2,2-trifluoroethane (Note 3), and phenyl disulfide (100 g., 0.458 mole) (Note 4) is weighed into the solid addition funnel. The stirrer is started, and phenyl disulfide is added to the slurry in small portions. An exothermic reaction occurs, and after the addition of several portions the reaction mixture reaches a temperature of 40° (Note 5). By intermittent use of a cooling bath and by adjusting the rate of addition of the disulfide, the reaction temperature may be maintained between 35° and 40°. The addition of the phenyl disulfide requires 45-60 minutes. On completion of the addition the suspension of black silver difluoride has been converted to yellow silver monofluoride, and the exothermic reaction gradually subsides. The reaction mixture is stirred for an additional 15-30 minutes without external cooling and then quickly heated to reflux. 

The phosphorus pentoxide should be protected from atmospheric moisture by weighing this reagent in a dry, stoppered flask. 

The alkyne (15 mmol) is added to TBA-H2F3 (9 g, 30 mmol) in Cl(CH2)2Cl (l ml) and the mixture is protected from atmospheric moisture and heated until the reaction is complete. H20 (5 ml) is added and the mixture is extracted with Et20 (3 x 10 ml). The extracts are washed with H,0 to pH 5, dried (Na2S04), and evaporated to yield the Z- and f-fluoro-alkenes [e.g. MeOCOCF=CHC02Me (60°C, 30 h), 80% PhCF=CHC02Me (120°C,... 

A one-liter flask fltted with a stirrer, reflux condenser and separatory flask is charged with 7.6 g (0.2 mol) of lithium aluminum hydride and 500 ml of anhydrous ether. A solution of 44.4 g (0.6 mol) of anhydrous terr-butyl alcohol in 250 ml of ether is added slowly from the separatory funnel to the stirred contents of the flask. (The hydrogen evolved is vented to a hood.) During the addition of the last third of the alcohol a white precipitate is formed. The solvent is decanted and the flask is evacuated with heating on the steam bath to remove the residual ether and tert-butyl alcohol. The solid residue - lithium tri-/er/-butoxyaluminohydride - is stored in bottles protected from atmospheric moisture. Solutions 0.2 m in reagent are prepared by dissolving the solid in diglyme. 

The resulting reaction mixture, a clear yellow liquid containing a white opaque solid, is protected from atmospheric moisture by means of a calcium chloride drying tube and is set aside at room temperature for 1.5-2 hours. During this time slight effervescence continues (Note 3) and the white opaque suspended material gradually disintegrates to a finely divided translucent deposit. 

SYNTHESIS A solution of 0.50 g 4-acetoxyindole (see under 4-HO-DET for its preparation) in 5 mL Et20 was stirred and cooled to 0 °C with protection from atmospheric moisture. There was then added 0.5 mL oxalyl chloride. The reaction mixture was stirred for an additional 30 min, and the yellow crystalline solid was removed by filtration and dissolved in 10 mL of anhydrous THF. This was treated with a 40% solution of methyl isopropylamine in dry Et20, dropwise, until the pH of the... 

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