Insoluble sohds

The rate (kinetics) and the completeness (fraction dissolved) of oxide fuel dissolution is an inverse function of fuel bum-up (16—18). This phenomenon becomes a significant concern in the dissolution of high bum-up MO fuels (19). The insoluble soHds are removed from the dissolver solution by either filtration or centrifugation prior to solvent extraction. Both financial considerations and the need for safeguards make accounting for the fissile content of the insoluble soHds an important challenge for the commercial reprocessor. If hydrofluoric acid is required to assist in the dissolution, the excess fluoride ion must be complexed with aluminum nitrate to minimize corrosion to the stainless steel used throughout the facility. Also, uranium fluoride complexes are inextractable and formation of them needs to be prevented. 

In some cases, a single chemical substance can serve both as a dye and as a pigment. For example, indanthrone [81-77-6] (Pigment Blue 60) functions as a blue pigment or as a dye. As a pigment, indanthrone is a particulate, insoluble soHd dispersed directly into a vehicle, whereas as a dye it is reduced to a base-soluble hydtoquinone derivative and then reoxidized onto a soHd substrate. 

Molecular Weight. Measurement of intrinsic viscosity in water is the most commonly used method to determine the molecular weight of poly(ethylene oxide) resins. However, there are several problems associated with these measurements (86,87). The dissolved polymer is susceptible to oxidative and shear degradation, which is accelerated by filtration or dialysis. If the solution is purified by centrifiigation, precipitation of the highest molecular weight polymers can occur and the presence of residual catalyst by-products, which remain as dispersed, insoluble soHds, further compHcates purification. 

An attraction also exists at the interface between a Hquid and an insoluble soHd. The interfacial tension is lower than the sum of the surface tensions of the two phases. Duprn s equation is appHcable to the soHd—Hquid interface and has the foUowing form ... 

Leaching is the removal of a soluble fraction, in the form of a solution, from an insoluble, permeable sohd phase with which it is associated. The separation usually involves selective dissolution, with or without diffusion, but in the extreme case of simple washing it consists merely of the displacement (with some mixing) of one interstitial liquid by another with which it is miscible. The soluble constituent may be solid or liquid and it may be incorporated within, chemically combined with, adsorbed upon, or held mechanically in the pore structure of the insoluble material. The insoluble sohd may be massive and porous more often it is particulate, and the particles may be openly porous, cellular with selectively permeable cell walls, or surface-activated. 

Degree of methylation (DM%) of total pectin of carrot alcohol insoluble sohds (AIS) was decreased from 60.73% for fresh carrots to 48.70, 44.62 and 43.83% for canned carrots preheated at 65°C for 15. 30 and 60 min, respectively (Fig. 2). Similar levels of demethylation were also reported in potato (Bartolome and Hoff, 1972), in carrots (Lee et al., 1979) and in snap beans (Adams and Robertson, 1987) when they were blanched at low temperature between 65°C and 70°C. 

Creams tend to be invisible on the skin. The same is true for ointments, although the oiliness of ointments causes them to glisten to an extent. Whatever opacity creams and ointments have is due primarily to the presence of insoluble soHds. These often imbue applications with a powdery or even crusty appearance. Dispersed soHds are usually functional, as in calamine lotion, zinc sulfide lotion, zinc oxide paste, and so on, and are an implacable feature of these preparations. However, at times insoluble soHds are added as tints to match the color of the skin and to impart opacity. Since individual skins vary widely in hue (pigmentation) and texture, tinting to a single color and texture is generally unsuccessful. 

The simplest laboratory filter for liquids is a fluted glass funnel in which a cone of special paper, known as filter paper, is placed. The liquid to be filtered is passed through the paper filter, whereupon the insoluble sohds are retained on the filter. Grouch crucibles, which are special containers with a porous base of sintered glass, are also used as filters. 

A mixture of an alkene (1 1 mmol), Chloramine-T (2 1 mmol, 228 mg), Af-bromosuccinimide (10 mol%) and [bmim]BF4 (1 mL) in a 25 mL rotmd bottomed flask was stirred at room temperature for stipulated time (1-6.5 h). On completion of the reaction (monitored by TLC), the product was extracted by diethyl ether and purified by passing through a small column of silica gel using ethyl acetate/hexane (4 6) as eluent. Evaporation of the solvent under vacuum yielded pure aziridine 3 with good yield. Each of the products was identified by means of spectral methods. The ionic liquid layer containing succinimide and NaCl was diluted with ethyl acetate and insoluble sohds were separated by filtration through a small Buckner funnel. The ethyl acetate was evaporated under reduced pressure and ionic liquid was used for the next run. 

There are three processes involved in leaching or solid extraction. Dissolution of solids, separation of solvent from insoluble sohd material, and washing. Most of the leaching plants are operated batchwise. In a batch leaching, the solids are stationary and solvent is flowing through the bed of particles. 

This rare-earth catalyst could efficiently promote the multicomponent reactions, and the fluorinated catalyst could be recovered as an insoluble sohd after quenching the reaction. It was reused three times without significant loss of catalytic activity. 

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