Sodium high pressure

Yorio, N. C., Mackowiak, C. L., Wheeler, R. M., Sager, J. C. (1995b). Vegetative growth of potato under high-pressure sodium, high-pressure sodium SON-AGRO, and metal halide lamps. HortScL, 30, 374-376. 

High-Pressure Sodium. High-pressure sodium (HPS) lamps are very efficient in the production of raw lumens (high LPW), and they also have long life ratings. Their downfall, how-... 

Ingalls R, Crozier E D, Whitmore J E, Seary A J and Tranquada J M 1980 Extended x-ray absorption fine structure of sodium bromide and germanium at high pressure J. Appl. Phys. 51 3158... 

Sodium borohydride reduces esters but the reaction is too slow to be useful Hydrogenation of esters requires a special catalyst and extremely high pressures and tern peratures it is used m industrial settings but rarely m the laboratory... 

When levuhnic acid (CH3CCH2CH2CO2H) was hydrogenated at high pressure over a nickel catalyst at 220°C a single product C5Hg02 was isolated in 94% yield This compound lacks hydroxyl absorption in its IR spectrum and does not immediately liberate carbon dioxide on being shaken with sodium bicarbonate What is a reasonable structure for the compound" ... 

Kolbe-Schmitt reaction (Section 24 10) The high pressure re action of the sodium salt of a phenol with carbon dioxide to give an o hydroxybenzoic acid The Kolbe-Schmitt reac tion IS used to prepare salicylic acid in the synthesis of as pinn... 

Sulfomethylation. The reaction of formaldehyde and sodium bisulfite [7631-90-5] with polyacrylamide under alkaline conditions to produce sulfomethylated polyacrylamides has been known for many years (44—46). A more recent pubHcation (47) suggests, however, that the expected sulfomethyl substitution is not obtained under the previously described strongly alkaline conditions of pH 10—12. This C-nmr study indicates that hydrolysis of polyacrylamide occurs and the resulting ammonia reacts with the NaHSO and formaldehyde. A recent patent claims a new high pressure, high temperature process at slightly acid pH for preparation of sulfomethylated polyacrylamide (48). 

Niobium is used as a substrate for platinum in impressed-current cathodic protection anodes because of its high anodic breakdown potential (100 V in seawater), good mechanical properties, good electrical conductivity, and the formation of an adherent passive oxide film when it is anodized. Other uses for niobium metal are in vacuum tubes, high pressure sodium vapor lamps, and in the manufacture of catalysts. 

The second important component is the cooling agent or reactor coolant which extracts the heat of fission for some usefiil purpose and prevents melting of the reactor materials. The most common coolant is ordinary water at high temperature and high pressure to limit the extent of boiling. Other coolants that have been used are Hquid sodium, sodium—potassium alloy, helium, air, and carbon dioxide (qv). Surface cooling by air is limited to unreflected test reactors or experimental reactors operated at very low power. 

Superoxides are used in breathing appHcations requiring no auxHiary source of oxygen. Sodium superoxide is ca 10 times as expensive as potassium superoxide because high temperature, high pressure autoclaves are required for its production. Use of calcium superoxide is experimental. Potassium superoxide is the most commonly used superoxide oxygen generator. 

Dialkyl and diaryl dithiophosphoric acids are the bases of many high pressure lubricants, oil additives (see Lubrication and lubricants), and ore flotation chemicals (see Mineral recovery and processing). Organophosphoms insecticides such as Parathion are made by chlorination of the appropriate diaLkyl dithiophosphate and subsequent reaction of the intermediate dialkyl thiophosphoric chloride with sodium -nitrophenolate according to the following (see... 

AH commercial processes (8—10) use either NaOH (4) or Na2C02 (5) as solvent systems. The dissolving mechanism is similar ia both solvents because hydrolyzes to OH . Sodium salts are required because insoluble sodium iron sHicates form on the steel waHs of the high pressure vessels... 

Sodium is commonly shipped in 36- to 70-t tank cars in the United States. Smaller amounts are shipped in 16-t tank tmcks or ISO-tanks. Sodium is also available in 104- and 190-kg dmms, and in bricks (0.5—5 kg). A thin layer of oxide, hydroxide, or carbonate is usually present. Sodium is also marketed in small lots as a dispersion in an inert hydrocarbon, or produced in-process via high pressure injection into a pumped stream of inert carrier fluid, such as toluene or mineral oil. 

Demineralization. Softening alone is insufficient for most high-pressure boiler feed waters and for many process streams, especially those used in the manufacture of electronics equipment. In addition to the removal of hardness, these processes require removal of all dissolved soHds, such as sodium, sihca, alkalinity, and the mineral anions (Cl , and NO ). 

Manufacture. Ethyl chloride undergoes reaction with alkah cellulose in high pressure nickel-clad autoclaves. A large excess of sodium hydroxide and ethyl chloride and high reaction temperatures (up to 140°C) are needed to drive the reaction to the desked high DS values (>2.0). In the absence of a diluent, reaction efficiencies in ethyl chloride range between 20 and 30%, the majority of the rest being consumed to ethanol and diethyl ether by-products. 

If the pump is a filter pump off a high-pressure water supply, its performance will be limited by the temperature of the water because the vapour pressure of water at 10°, 15°, 20° and 25° is 9.2, 12.8, 17.5 and 23.8 mm Hg respectively. The pressure can be measured with an ordinary manometer. For vacuums in the range lO" mm Hg to 10 mm Hg, rotary mechanical pumps (oil pumps) are used and the pressure can be measured with a Vacustat McLeod type gauge. If still higher vacuums are required, for example for high vacuum sublimations, a mercury diffusion pump is suitable. Such a pump can provide a vacuum up to 10" mm Hg. For better efficiencies, the pump can be backed up by a mechanical pump. In all cases, the mercury pump is connected to the distillation apparatus through several traps to remove mercury vapours. These traps may operate by chemical action, for example the use of sodium hydroxide pellets to react with acids, or by condensation, in which case empty tubes cooled in solid carbon dioxide-ethanol or liquid nitrogen (contained in wide-mouthed Dewar flasks) are used. 

Because of quite poor color rendition and difficulty in safe disposal of expended lamps, low pressure sodium fixtures are less desirable than high pressure sodium fixtures and are seldom recommended for production facilities. High pressure sodium fixtures are particularly attractive for illuminating large open areas. At locations where power cost is low and where many fixtures are required due to equipment shadowing, mercury vapor fixtures often are preferred because of their lower initial cost, lower replacement lamp cost, and better color rendition. 

Hydrolysis of chlorobenzene Heating chlorobenzene with aqueous sodium hydroxide at high pressure gives phenol after acidification. 

Lamp types (a) incandescent and tungsten-halogen lamp shapes (b) fluorescent and compact fluorescent lamp shapes (c) typical high-pressure sodium lamp (d) typical metal halide lamp. 

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