Inert diluent

Reactor diluents and solvents. As pointed out in Sec. 2.5, an inert diluent such as steam is sometimes needed in the reactor to lower the partial pressure of reactants in the vapor phase. Diluents are normally recycled. An example is shown in Fig. 4.5. The actual configuration used depends on the order of volatilities. 

Starch is insoluble in cold water, but in hot water the granules gelatinize to form an opalescent dispersion. It is made from corn, wheat, potatoes, rice and other cereals by various physical processes such as steeping, milling and sedimentation. It is used as an adhesive, for sizing paper and cloth, as an inert diluent in foods and drugs, and for many other purposes. 

In pack cementation, the part to be coated is placed in a retort and surrounded with a powdered pack consisting of the coating component and an activator the latter reacts with the coating component to form the carrier vapor, usually a haHde or an inert diluent, to prevent the pack from sintering together and to permit vapor transport of the alloying component through the pack. 

For extraction of uranium from sulfate leach Hquors, alkyl phosphoric acids, alkyl phosphates, and secondary and tertiary alkyl amines are used in an inert diluent such as kerosene. The formation of a third phase is suppressed by addition of modifiers such as long-chain alcohols or neutral phosphate esters. Such compounds also increase the solubihty of the amine salt in the diluent and improve phase separation. 

When catalysts are used in a highly exothermic reaction, an active phase may be diluted with an inert material to help dissipate heat and moderate the reaction. This technique is practiced in the commercial oxychlorination of ethylene to dichloroethane, where an alumina-supported copper haUde catalyst is mixed with a low surface area inert diluent. 

The oxychlorination reaction is very exothermic and the catalyst is very active, which makes it necessary to mix the catalyst with an inert diluent to avoid overheating in a fixed-bed reactor. A low surface area, spherically- or ring-shaped alumina or chemical porcelain body can be used as a diluent with the ring-shaped catalyst. The density of the inert material should be similar to the catalyst to avoid segregation during loading, and the size should be slightly different to allow separation of the inert material from the spent catalyst. 

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. 

Hydrogen fluoride adds to more complex molecules, such as unsaturated steroids, to give fluorinated derivatives [/, 8] Low temperatures and inert diluents, such as tetrahydrofuran or methylene chloride, are generally employed. With bicyclic unsaturated terpenes, rearrangements often accompany addition to the double bond [/]. 

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. 

Removal of diluent by an extraction process To obtain the final stable macroporous structure, the liquid organic diluents and the linear polymer are removed from the crosslinked structure by extraction with a good solvent for the inert diluents and particularly for the linear polymer. Toluene or methylene chloride are usually preferred for the removal of linear polystyrene from the divinylbenzene crosslinked macroporous polystyrene particles [125,128]. The extraction is carried out within a Soxhelet apparatus at the boiling point of the selected solvent over a period usually more than 24 h. 

A research group in Lehigh University has extensively studied the synthesis and characterization of uniform macroporous styrene-divinylbenzene copolymer particles [125,126]. In their studies, uniform porous polymer particles were prepared via seeded emulsion polymerization in which linear polymer (polystyrene seed) or a mixture of linear polymer and solvent were used as inert diluents [125]. The average pore diameter was on the order of 1000 A with pore volumes up to... 

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. 

The polymerizations were conducted in a 20-liter stainless steel reactor with a pitched-blade turbine agitator and four side-wall baffles. The monomer was polymerized at the same temperature, initiator and monomer concentration in two different inert diluents. The data (Figure 6) illustrate the substantial lowering of the overall heat transfer coefficient for the system with the more highly swollen particles. 

Supported bimetallic Re—Pt catalysts are important in selective reforming of petroleum. It is believed that sulhding the catalyst before use gives ReS units which act as inert diluents to reduce the size of a local ensemble of platinum atoms. Selectivity for desirable dehydrocyclization and isomerization reactions... 

To test their inhibitory power, the powders may be dusted onto the surfaee of seeded agar plates, using the inert diluent as a control and noting the extent of growth. 

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. 

Poly(silylene) polymers are usually made by the reaction of diorganodichlorosilanes with sodium metal, in an inert diluent at temperatures above 100°C. (11.) Rapid stirring is ordinarily used so that the sodium is finely dispersed, speeding the rate of reaction. Either homopolymers or copolymers can be synthesized ... 

The stereospecificity of addition suggests a singlet(10) carbene although the ground state of cyclopentadienylidene is known to be a triplet. Attempts to produce a triplet species, which would be expected to react nonstereospecific-ally, in a 4-methyl-cw-2-pentene matrix at 77°K or by dilution of mixtures of the azo compound and olefin with hexafluorobenzene or octafluorocyclo-butane (inert diluents) were unsuccessful. It was concluded that the singlet carbene produced upon photolysis reacts more rapidly with the olefinic... 

Addition of diphenyl ether as an inert diluent to the crude ether before distillation at... 

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