Solvents dilutability

Insofar as they are used to purify other products, several processes used in the refinery fall under the classification of dewaxing processes however, such processes must also be classified as wax production processes (2). Most commercial dewaxing processes utilize solvent dilution, chilling to crystallize the wax, and filtration (28). The MEK process (methyl ethyl ketone—toluene solvent) is widely used. Wax crystals are formed by chilling through the walls of scraped surface chillers, and wax is separated from the resultant wax—oil—solvent slurry by using fliUy enclosed rotary vacuum filters. 

The process described above is usually called osmosis and this usually imphes a flow of fluid in one direction or the other. If the permeating species, usually called the solvent, flows from the pure compartment to the mixture compartment then it is called osmosis pure and simple. This seems the natural process since the solvent dilutes the solution and this involves an increase in entropy and/or a decrease in free energy, so the resultant flow is spontaneous and the system tends to equihbrium. However, the starting conditions may be such that the difference of pressure... 

In solution polymerization, monomers mix and react while dissolved in a suitable solvent or a liquid monomer under high pressure (as in the case of the manufacture of polypropylene). The solvent dilutes the monomers which helps control the polymerization rate through concentration effects. The solvent also acts as a heat sink and heat transfer agent which helps cool the locale in which polymerization occurs. A drawback to solution processes is that the solvent can sometimes be incorporated into the growing chain if it participates in a chain transfer reaction. Polymer engineers optimize the solvent to avoid this effect. An example of a polymer made via solution polymerization is poly(tetrafluoroethylene), which is better knoivn by its trade name Teflon . This commonly used commercial polymer utilizes water as the solvent during the polymerization process,... 

Moreover, the membrane could be mounted as an interface between the apolar substrate and the polar oxidant in a membrane reactor, avoiding the use of any solvent. Dilution of the reagents by solvent and competition between solvent and reagents on the active sites can thus be avoided. In the countercurrent membrane reactor, the substrate and the oxidant are circulated at each side of the membrane and alkanes can be oxidized with peroxides without solvents. Of course, the system carries all of the other advantages of membrane reactors continuous operation and easy separation. 

Test solution. Dissolve 0.25 g of the substance to be examined in the internal standard solution and dilute to 5.0 mL with the same solvent. Dilute 1.0 mL of the solution to 10 mL with heptane. 

Vlt 2.9 ppm H2O Miscible Sol Most organic solvents Dilute mineral acids... 

Kiguchi, M. (1993). Chemical modification of wood surfaces by etherification. IV. Benzylation with solvent-dilution and vapor-phase methods. Mokuzai Gakkaishi, 39(1), 80-85. 

If a diesel fuel is low in viscosity due to kerosene dilution or solvent dilution, its lubricity is probably poor. The possibility of wear of the high-pressure fuel injection pump parts will increase. The effect of kerosene dilution on the lubricity of a typical low sulfur diesel fuel is shown in FIGURE 5-2. 

When contaminated or held in storage at temperatures below 60°F (15.5°C), hindered phenols may tend to crystallize and fall from solution as relatively pure compounds. Often solvent dilution of hindered phenols can help to reduce the tendency of crystal dropout, but will not completely eliminate this problem. 

Additional solvent effects, like ion pairing, occur in not-so dilute solutions. At higher concentrations in solution with bulky solvents, a lack of sufficient solvent dilution may take place. Neighboring ions will share solvent molecules. 

Solvent Diluting liquid Average crystal size Limits of the crystal size M Ratio (length) (width)... 

Other Preparation Methods Organic Solvent Dilution Method... 

Short contact time SRC can be upgraded via catalytic hydroprocessing into low sulfur boiler fuels. However, the solid SCT SRC feedstock requires solvent dilution to reduce its viscosity. Furthermore, even for a 50 wt % W. Kentucky SCR SRC blend, all pilot unit lines and valves have to be heat-traced above 350°F in order to achieve smooth mechanical operations. 

Compared to the boiling point of the pure solvent, dilute solutions containing that solvent boil at a higher temperature. In dilute solutions, the elevation of the boiling point is directly proportional to the number of moles solute (or molecules). The equation for the change in boiling point is... 

For reactions that take place in solution, increasing the amount of solvent (dilution) will displace the equilibrium in the direction of forming the larger number of dissolved particles. This is pretty much the same concept as discussed above in relation to the behavior of gases. 

The question of iron(III) tetraphenylporphyrin mimic stabilization [44-46] is resolved by replacing all phenyl hydrogen atoms by halides, which significantly extends the lifetime of the catalyst. It is also proven that oxidants (H202, ROOH, peroxy acids and iodosylben-zene) in hydroxide solvents (diluters) dissociate heterolytically [30, 31],... 

The codeine that occurs naturally in small amounts in opium is isolated from the aqueous morphine alkaloid mother liquors by immiscible extraction with a nonaqueous solvent. Dilute sulfuric acid is employed to extract the codeine sulfate from the nonaqueous solvent. This solution is evaporated, crystallized, and recrystallized. The alkaloid is precipitated from a sulfate solution by alkali and purified, if necessary, by alcoholic crystallization. It is converted into the phosphate by solution in phosphoric acid, evaporation, crystallization, centrifugation, and drying. 

Adjust or change sample solvent. Dilute sample in mobile phase whenever possible. 

The instability of cyclopentadiene also required detailed study. Under adiabatic conditions, cyclopentadiene can spontaneously dimerize exothermically and thus should be stored cold for only short duration, especially on kilogram scales (Scheme 3). The impact of container size, volume, temperature, and solvent dilution on storage conditions was carefully studied to assess the potential of a runaway reaction. The published results of this analysis clearly show that hazards increase significantly as the volume of stored cyclopentadiene increases.35 These generation and storage issues of a simple yet key building block threatened the earliest step in the benzazepine sequence. 

Test 2 Dissolve 10 mg in a mixture of 1 volume of 0.1 M hydrochloric acid and 9 volumes of methanol R, and dilute to 50 mL with the same mixture of solvents. Dilute 5 mL of this solution to 100 mL with a mixture of 1 volume of 0.1 M hydrochloric acid and 9 volumes of methanol R. Examine between 220 nm and 350 nm, where the solution will exhibit... 

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