Inert diluent process

The unusual sensitivity of some composite-modified double-phase propellants before curing has justified intensive effort to exploit a nonmechanical mixing process. First introduced in about 1959 as the quick-mix process by Rocketdyne Division of North American Aviation (5, 10), the inert diluent process has been developed at the Naval Ordnance Station, Indian Head, Md. for application to a variety of propellant compositions. Separate streams of solids, slurried in heptane, and an emulsion of plasticizers in heptane, are combined in a non-mechanical mixing chamber. The complete propellant slurry is allowed to settle, and the heptane is separated and recycled in a continuous operation. Figure 1... 

Figure I. Inert diluent process flow diagram Adhesives for Case Bonding...

Since each bead of a given external diameter that is made by the inert diluent process will contain some void volume, there is actually less polymer available per unit volume for the introduction of functional groups. Therefore, these macroporous resins are inherently of lower total exchange capacity than gel-type resins of the same composition. 

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 order to faciUtate heat transfer of the exothermic polymerization reaction, and to control polymerizate viscosity, percent reactives are adjusted through the use of inert aromatic or aUphatic diluents, such as toluene or heptane, or higher boiling mixed aromatic or mixed aUphatic diluents. Process feed streams are typically adjusted to 30—50% polymerizable monomers. 

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. 

As the range of components available for use in the azoic dyeing process expanded, research was simultaneously targeted on improvements designed to make the process more attractive to the commercial dyer. The necessity for the dyer to diazotise the Fast Base was removed with the introduction of stabilised diazonium salts [111], known as Fast Salts. Stabilisation was achieved by a judicious selection of the counter-ion to the diazonium cation various anions have found use in commercial Fast Salts and some examples are listed in Table 4-4. Particularly effective is the diazonium tetrachlorozincate, which can be readily prepared by adding an excess of zinc chloride solution to a solution of the diazonium salt. The precipitated complex diazonium salt is usually admixed with an inert diluent, which enhances its stability, and in use the dyer only needs to dissolve the powder in water to prepare the necessary diazonium salt solution. 

Desulphurisation of hydrocarbon fuels prior to combustion has been seen to be primarily achieved by reducing the inherent sulphur values to hydrogen sulphide. In post combustion desulphurisation the sulphur values are almost exclusively in the oxidised SO2 form. While this is hardly surprising in view of the oxidative nature of the fuel combustion process, it does mean that essentially different chemistry is involved and the nature of the oxidant - air - introduces large volumes of inert diluent -nitrogen. 

The mixture leaving the reaction zone is in the form of a hydrocarbon-acid emulsion and passes to an acid settler for separation of acid and hydrocarbon phases. This acid settler is usually a separate vessel from the reactor itself, although it is an integral part of one type of system. The hydrocarbon-free acid from the acid settler recirculates to the reactor. The hydrocarbon layer, which consists of alkylate, excess isobutane, and the inert diluents introduced with the feed, receives a caustic treatment and goes to the fractionating section of the plant. Caustic treatment is necessary at this stage of the process to neutralize acidic components, such as sulfur dioxide, which are formed in small quantities by catalyst degeneration. 

This chapter shows that eutectic-based ionic liquids can be made in a variety of ways. The above description of liquids falling into three types is by no means exclusive and will certainly expand over the coming years. While there are disadvantages in terms of viscosity and conductivity these are outweighed for many metal deposition processes by issues such as cost, ease of manufacture, decreased toxicity and insensitivity to moisture. The high viscosity of some of these liquids could be ameliorated in many circumstances by the addition of inert diluents. 

In some oases even inert diluents can influence the rate constant of radical processes. This effect has been interpreted in radical polymerization by assuming the existence of hot radicals (Tiidos, 1964a, 1965a, b). 

Butyl rubber is produced at very low temperature (below — 90°C) to control the rapid exotherm, and to provide high molecular weight. The process consists of charging isobutylene along with isoprene (2-4%) with an inert diluent such as methyl chloride to a reactor to which a Friedel-Crafts catalyst is added. The polymerization is very rapid, and the polymer forms in a crumb or slurry in the diluent. Heat is removed via the reactor jacket. The slurry is steam-stripped to remove all volatiles. The catalyst is neutralized, and antioxidants are added to the slurry prior to drying.53 The halogenated derivatives are produced by the direct addition of the halogen to a solution of the isobutylene-isoprene polymer. 

The main characteristics of the green mixture used to control the CS process include mean reactant particle sizes, size distribution of the reactant particles reactant stoichiometry, j, initial density, po size of the sample, D initial temperature, Tq dilution, b, that is, fraction of the inert diluent in the initial mixture and reactant or inert gas pressure, p. In general, the combustion front propagation velocity, U, and the temperature-time profile of the synthesis process, T(t), depend on all of these parameters. The most commonly used characteristic of the temperature history is the maximum combustion temperature, T -In the case of negligible heat losses and complete conversion of reactants, this temperature equals the thermodynamically determined adiabatic temperature (see also Section V,A). However, heat losses can be significant and the reaction may be incomplete. In these cases, the maximum combustion temperature also depends on the experimental parameters noted earlier. 

Prior to digestion, the ore must be finely ground. The chromium ore concentrate enriched by gravitational processes (e.g. spiral classifiers, settling machines etc.) is supplied with a particle size of ca. 0.5 mm. Ball-milling coupled with air classifiers yields a particle size of <0.1 mm. The sodium carbonate is also ground. Since the sodium chromate formed melts at 792°C, the addition of an inert diluent, which can absorb sodium chromate like a sponge, is necessary to enable air to come into contact with the reaction mixture. 

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