Solid reagents

Alternatively, dissolve approximately equivalent amounts of the aldehyde (or ketone) and the solid reagent in the minimum volume of cold glacial acetic acid, and reflux for 15 minutes. The p-nitrophenyl-hydrazone separates on cooling or upon careful dilution with water. 

Important auxiliary equipment in a flotation plant includes feeder and controls, sampling and weighing devices, slurry pumps, filter and thickeners for dewatering solids, reagent storage and makeup equipment, and analytical devices for process control. 

Limestone is pulverized to 80 to 90 percent through 200 mesh. Shiny concentrations of 5 to 40% have been checked in pilot plants. Liquid to gas ratios are 0.2 to 0.3 gaLMSCF. Flue gas enters at 149°C (300°F) at a velocity of 2.44 m/s (8 ft/s). Utilization of 80 percent of the solid reagent may be approached. Flow is in parallel downward. Residence times are 10 to 12 s. At the outlet the particles are made just diy enough to keep from sticking to the wall, and the gas is within 11 to 28°C (20 to 50°F) of saturation. The fine powder is recovered with fabric filters. 

Handhng of this volatile and toxic matenal may be avoided by the clever use of the trimethylsilylated perfluorinated resinsulfonic acid [97] This solid reagent is prepared by treatment of the acid form of NAFTON 511 with chloro-tnmethylsilane This reagent exhibits sigmficant stabdity in air (equation 78)... 

The indicator solution is prepared by dissolving 0.05 g of the solid reagent in 100 mL of 50 per cent ethanol. 

Procedure. Prepare the CDTA solution (0.02M) by dissolving 6.880 g of the solid reagent in 50 mL of sodium hydroxide solution (1M) and making up to 1 L with de-ionised water the solution may be standardised against a standard calcium solution prepared from 2.00 g of calcium carbonate (see Section 10.61). The indicator is prepared by dissolving 0.5 g of the solid in 100 mL of water. 

Solutions of cerium(IV) sulphate may be prepared by dissolving cerium(IV) sulphate or the more soluble ammonium cerium(IV) sulphate in dilute (0.5-1.0M) sulphuric add. Ammonium cerium(IV) nitrate may be purchased of analytical grade, and a solution of this in 1M sulphuric add may be used for many of the purposes for which cerium(IV) solutions are employed, but in some cases the presence of nitrate ion is undesirable. The nitrate ion may be removed by evaporating the solid reagent which concentrated sulphuric add, or alternatively a solution of the nitrate may be predpitated with aqueous ammonia and the resulting cerium(IV) hydroxide filtered off and dissolved in sulphuric acid. 

Notes. (1) Prepare the sodium TPB reagent by dissolving 3.0 g of the solid reagent in 500 mL distilled water in a glass-stoppered bottle. Add about 1 g moist aluminium hydroxide gel, break up the gel if necessary, and shake the suspension for 15 minutes. Filter through a Whatman No. 40 filter paper. Re-filter the first part of the filtrate, if necessary, to ensure a clear filtrate. 

Reagents. Eriochrome cyanine R solution. Dissolve 0.1 g of the solid reagent in water, dilute to 100 mL, and filter through a Whatman No. 541 filter paper if necessary. This solution should be prepared daily. 

Sodium disulphite solution (sodium metabisulphite). Dissolve 0.5 g of the solid reagent (Na2S205) in 10 mL water. Prepare fresh daily. 

Reagents. Bicyclohexanone oxalyldihydrazone solution (copper reagent). Dissolve 0.1 g of the solid reagent in 10 mL ethanol (or industrial methylated spirit) and 10 mL hot water, and dilute to 200 mL. Filter, if necessary. 

Reagents. 2- ( 2-Hydroxy phenyl) benzoxazole solution. Dissolve 1.0 g of the solid reagent in 1 L of 95 per cent ethanol. 

Thiophenes of type 31 (X-Y = CH) were generated via Lawesson s reagent-mediated cyclization of 1,4-dicarbonyl compounds 30 under microwave irradiation in the absence of solvent [37]. The reaction was carried by mixing the two solid reagents in a glass tube inserted inside a household microwave apparatus and irradiating until the evolution of H2S ceased. An interesting application of this method is the preparation of liquid crystals and other ferro- and antiferroelectric material such as compound 33 (Scheme 10). 

The usual aromatic bromination are performed by free bromine in the presence of a catalyst, most often iron. However, liquid bromine is not easy to handle because of its volatile and toxic character. On the other hand, alumina-supported copper(II) bromide can be treated easily and safely as a solid brominating reagent for aromatic compounds. The advantages of this procedure using the solid reagent are simple workups, mild conditions, and higher selectivities. Products can be isolated in good yield by simple filtration and solvent evaporation, and no extraction steps are required. 

Most of the known organic reaction yield sooner or later precipitates or involves directly the addition of solid reagents [78]. Hence fouling phenomena are rather... 

Theoretical model porous electrode solid reagent dissolution electrochemical reaction crystallization polarization characteristic chloranile carbon black. 

There appears to be a more adequate approach when a local polarization characteristic is obtained as a result of analysis of the processes in the elementary cell and the local section of the electrode. This characteristic depends on the state transformation of the solid reagents and the concentrations of the electrolyte components. It further may be introduced into the equations describing the macrokinetic processes in an electrode, and may be used to model the behaviour of the system as a whole. 

Herein, we consider the case when a porous conducting matrix with inclusion of active solid reagents represents the electrode. It is supposed, that both the reagent and the product are nonconductive. The conversion of the solid reagents is assumed to proceed via a liquid-phase mechanism in the following way dissolution - electrochemical reaction - crystallization. Figure 1 shows the structure of the electrode and its model. The model has been developed on the bases of several assumptions. 

Figure 1. Typical structure of the porous electrode with solid reagents and schematic representation of the proposed physical model. 

Here ir is the local polarization characteristic (3). v is the stoichiometric coefficient of substance i (Vj > 0, v2 <0). With these coefficients, the reagent and product are included into the equation of the electrode reaction. A. A is the diffusion coefficient of the dissolved solid reagent... 

Polarization Characteristic Relating to a Unit of the Solid Reagent Mass... 

Here, Ari) is the size distribution function of the initial solid reagents... 

The electrode current density is depends mainly on the solid reagents solubility and on the initial size of crystals... 

Since the specific surface area of modem graphite materials is Sv 104 -r- lO m 1 (Sm 10-2 - 104m2g 1 ), it is almost always possible to make an electrode characterized by A > 1 from a mixture of a carbon material and a solid reagent. 

In calculations the values of 8j = 82= 0.98 were used. The average size of the crystals ( rx 6.2pm) have been defined with the help of a photomicrography of the active mass. As concentration of electrolyte did not change during the reaction, then Ck= 1, C = 1. The change of solid reagents... 

The proposed model generally describes the electrochemical process, when the solid reagent and the product have precise phase borders and the electrochemical reaction taking place on the surface, which does not vary essentially with the time. 

Dissolve NHS-LC-biotin (Thermo Fisher) in dry DMF at a concentration of 40 mg/ml. This stock solution is stable for reasonable periods, although long-term storage is not recommended. For use of the water-soluble sulfo-NHS-LC-biotin, a stock solution may be prepared in either organic solvent or water, or the solid reagent may be added directly to the reaction mixture. If a solution in water is made to facilitate the addition of a small quantity of reagent to a reaction, then the solution should be prepared quickly and used immediately to prevent hydrolysis of the NHS ester. Sulfo-NHS-LC-biotin may be dissolved in water at a concentration of 20 mg/ml. 

These results provide clear evidence for the existence of selective heating effects in MAOS involving heterogeneous mixtures. It should be stressed that the standard methods for determining the temperature in microwave-heated reactions, namely with an IR pyrometer from the outside of the reaction vessel, or with a fiber-optic probe on the inside, would only allow measurement of the average bulk temperature of the solvent, not the true reaction temperature on the surface of the solid reagent. 

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