Nitrogen grades

General Electric lamp-grade nitrogen, 2 p.p.m. oxygen, is passed through traps containing chromium (II) solutions. 

Commercially available potassium superoxide and tetramethylammonium hydroxide pentahydrate from Aldrich were used as supplied without further purification. Industrial-grade nitrogen gas does not require any further purification, but the ammonia gas, 99.999%, should be at a minimum purged through Drierite before use. AU work is done under a nitrogen flow unless otherwise stated. 

Plant material containing proanthocyanidins 66% (v/v) aqueous acetone, HPLC grade Nitrogen gas... 

Pressure Reactions The Parr pressure reaction apparatus (Parr Instrument Co., Moline, Illinois) was used for all pressure and gas studies. A specially designed Teflon stopper was used in place of the original rubber stopper so that the commercial antioxidants in the rubber would not contaminate the reaction mixture. Standard 99.9% oxygen, lamp-grade nitrogen, and Type-1 grade-E breathing air were obtained from Sooner Supplies (Shawnee, Oklahoma). 

Nitrogen is used to blanket the reaction and the raw materials to stop the absorption of moisture and to prevent oxidation of the product. The dew point of a gas is the temperature at which the water vapor present in the gas saturates the gas and begins to condense. Dew points of below 0°C are sometimes called the hoar-frost point. Industrial-grade nitrogen gas normally is dry enough for use. 

Commercial prepurified-grade nitrogen is satisfactory and may be used without further purification. 

All polymerizations were conducted in a 500 ml three-necked round bottom flask equipped with stirrer, reflux condenser, and zero grade nitrogen inlet. The flask submerged in a constant temperature bath at 50 ... 

In order to maintain reproducibility it is important to measure all volumes accurately. In a typical operation using 500 ml (one pint) cans, the procedure is to place 300 ml of degassed salt-water brine into the 500 ml can and add sediment until the can is filled to the brim, giving 200 ml of sediment and 300 ml of brine. The can is sealed and then zero-grade nitrogen is injected through a prepared septum to displace 100 ml of brine and leaving the can with a 2 2 1 mixture of 200 ml brine, 200 ml sediment, and 100 ml headspace. 

In a 5 mL test tube dissolve 25 mg of theophylline (0.139 mmol) in 1.6 mL of a cyclohexanol - dodecanol mixture (25 +7v/v) (note 1). Then, add 47 pL (0.556 mmol, molar ratio template - functional monomer 1 4) of methacrylic acid, 0.84 mL of ethylene dimethacrylate (4.45 mmol, molar ratio fixnctional monomer - cross-linker 1 8) and about 8 mg of AIBN (protocol 1, note 2). Sonicate the mixture until complete dissolution of the theophylline. Purge the flask with analytical-grade nitrogen for 5 min, then transfer 0.600 mL of prepolymerization mixture into a 50 x 3.9 mm stainless-steel HPLC column, close it with airtight plugs (note 2) and leave it to polymerize overnight at 60°C in a waterbath (note 3). A blank polymer can be prepared in the same manner, omitting the theophylline. 

Grade Nitrogen content Degree of substitution Soiubiiity... 

Cylinder of j ero Grade Nitrogen (Industrial), with 2-stage regulator, for delivery pressure of 0 to 200 kPa (0 to... 

Welcome to Beaver Gas Co. Your first task is to calculate the annual gross sales of our superpure-grade nitrogen and oxygen gases. 

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