Inert diluent gases

There has been some controversy about the need for N2 in the formation of HD. Burgess et al. [29] reported that N2 was not required. They used argon as their diluent gas and took the word of the supplier that it was free of N2. Not only is commercial argon seldom free of N2, but it is difficult to remove the last traces of N2, and very little N2 is required to support HD formation. To settle this difference in experimental observations, Li and Burris [30] made it a point to rid their diluent gas of contaminating N2. One can absorb N2 on molecular sieve at liquid N2 temperature the problem is that argon liquefies and freezes before you get down to die temperature of liquid N2. So Li used neon as his inert gas and captured any contaminating N2 on molecular sieve in a liquid N2 bath. When the atmosphere above the nitrogen-ase system was carefully freed of N2 there was no formation of HD. 

Hydrazoic acid is unique in that both the aqueous and gaseous phase are explosive hazards. Detonations of hydrazoic acid solutions are capable of causing serious injury. It is possible to work with gaseous HNs.if an inert diluent gas is used. 

The second method is chemical vapor deposition (CVD). As suggested by the name, unlike PVD, chemical reactions are involved in CVD. Precursor materials in gas phases are introduced into heated furnaces and react at the substrate surface to deposit the desired thin film. For example, CVD is typically performed in low pressure conditions (< 1 Torr) this technique is called LPCVD and usually requires an inert diluent gas such as nitrogen. CVD processes typically involve high temperatures (above 500°C). This is a very important factor to consider in a designing a fabrication process. For example, no metal except tungsten (W) is allowed into CVD furnaces. LPCVD usually has very slow deposition rate. Plasma-enhanced CVD (PECVD) can deposit dielectric films much faster. It also allows deposition at lower temperatures (<400°C). This is very useful when a substrate has already been metalized. 

A repetitively pulsed HF or DF chemical laser is used to excite either HF or DF to the V = 1 level in a fluorescence cell. A sufficient quantity of an inert diluent gas such as argon is employed in the cell to ensure rotational thermal-ization and to provide a buffer against diflFusive deactivation at the cell wall surfaces. Fluorescences from HF(v = 1) or DF(v = 1) levels, and fluorescences from the vibrational bands of admixed gases, are isolated by narrow-band interference filters. The temporal behavior of the fluorescence from a... 

Gaseous elements and inorganic compounds (see the next paragraphs for examples) act as inert inhibitors in the explosion of HN3 organic diluents lead to additional side reactions, which are described on p. 149. The explosion limit of HN3 shifts to higher pressures when the diluent gas pressure is increased at moderate temperatures. The individual hyperbolic curves at low total pressures become linear at higher total pressures [9]. Changing the temperature between 288 and 373 K had only a small effect on the lower explosion limit [63]. 

Explosion prevention can be practiced by mixing decomposable gases with inert diluents. For example, acetylene can oe made nonexplosive at a pressure of 100 atm (10.1 MPa) by including 14.5 percent water vapor and 8 percent butane (Bodurtha, 1980). One way to prevent the decomposition reaction of ethylene oxide vapor is to use methane gas to blanket the ethylene oxide hquid. 

About two-thirds of the N2 produced industrially is supplied as a gas, mainly in pipes but also in cylinders under pressure. The remaining one-third is supplied as liquid N2 since this is also a very convenient source of the dry gas. The main use is as an inert atmosphere in the iron and steel industry and in many other metallurgical and chemical processes where the presence of air would involve fire or explosion hazards or unacceptable oxidation of products. Thus, it is extensively used as a purge in petrochemical reactors and other chemical equipment, as an inert diluent for chemicals, and in the float glass process to prevent oxidation of the molten tin (p. 370). It is also used as a blanketing gas in the electronics industry, in the packaging of processed foods and pharmaceuticals, and to pressurize electric cables, telephone wires, and inflatable rubber tyres, etc. 

Plating is carried out in a closed system whose atmosphere is adjusted to contain the metal-gas and a second gas which may be an inert diluent or a reactive gas (as in 1 above). is heated, for example by high frequency, and this then initiates deposition of M, by one of the above steps. Spent reaction products are exhausted and where possible reclaimed and recycled. 

For example, a microwave discharge on H2 in an inert diluent, such as argon gas, is an efficient method for producing H atoms as reactants. Subsequent reaction of these H atoms with NO2 will yield OH and NO, and can serve as a useful source of hydroxyl radicals. These methods of reactant formation are well suited for experiments involving either static or flow reactor systems. 

Metallocenes are homogeneous catalysts that are often soluble in organic solvents. Therefore, polymerization can occur via a solution process with a non-polar diluent dissolving the propylene gas, the catalyst, and the co-catalyst system. They can also be adsorbed onto an inert substrate which acts as part of the fluidized bed for gas phase polymerization processes. 

Shock tube experiments by Jacobs27 have shown that it is essential to purify the ammonia and the diluent from oxygen or other oxidizing components, otherwise oxidation would seriously interfere with decomposition. Jacobs followed the decay of ammonia through its infrared emission at 3 n in the temperature range 2100-3000 °K. He argued that an assumed reaction order of in ammonia and of i in the inert gas would best fit the observed concentration-time records, i.e. 

These experiments were extended by Hamill et a .12, who used helium, argon and hydrogen as inert diluents. Addition of these gases also produced an increase in k3fk2, which approached a limiting value, (k3jk2)[Pg.145]

As increasing amounts of an incombustible gas or vapor are added to the atmosphere, the flammability limits of a gaseous fuel in the atmosphere approach one another and finally meet. Inert diluents such as C02, N2, or Ar merely replace part of the 02 in the mixture, but these inert gases do not have... 

Fuel Hydrogen for PAFC power plants will typically be produced from conversion of a wide variety of primary fuels such as CH4 (e.g., natural gas), petroleum products (e.g., naphtha), coal liquids (e.g., CH3OH) or coal gases. Besides H2, CO and CO2 are also produced during conversion of these fuels (unreacted hydrocarbons are also present). These reformed fuels contain low levels of CO (after steam reforming and shift conversion reactions in the fuel processor) which cause anode poisoning in PAFCs. The CO2 and unreacted hydrocarbons (e.g., CH4) are electrochemically inert and act as diluents. Because the anode reaction is nearly reversible, the fuel... 

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