Solvent ratio

The solvent ratio of a semipaste remover may also be analy2ed by gas—Hquid chromatography by separating the solvents from the thickener. It is also useful to determine the viscosity and flow characteristics of the semipaste remover. A Brookfield viscometer is effective in determining the viscosity of most semipaste removers. Plow characteristics may be deterrnined by a constantometer. 

Temperature, solvent ratio, and pressure each have an effect upon the spHt point or yield of the oil and asphalt components (Table 3). Contrary to straight reduction which is a high temperature and low pressure process, propane deasphalting is a low temperature and high pressure process. 

A more complex reaction model was proposed from the results of a kinetic study of thermal liquefaction of subbituminous coal. Data were obtained over a temperature range of 673 to 743 K (752 to 878°F) at 13.8 MPa (2000 psia) by using two solvents, hydrogenated anthracene oil (HAO), and hydrogenated phenanthrene oil (HPO), at a coal-solvent ratio of 1 15. Results were correlated with the following model ... 

A purified fatty acid is recommended for the preparation of a pure a-sulfo acid. Purified palmitic acid (m.p. 60.8-61.4°, neutralization equivalent 256.2) is prepared by twice recrystallizing a good commercial grade of palmitic acid from acetone at 0°, using a solvent ratio of 10 ml. to 1 g. However, the reaction may be applied to commercial saturated higher fatty acids, if the iodine number is sufficiently low. The checkers obtained similar results with recrystaUized Neo-Fat 1-56 (Armour and Company, Chicago, 111.) or Eastman white label palmitic acid. 

The solubility of many steroids in ammonia-tetrahydrofuran-/-butyl alcohol is about 0.06 A/, a higher concentration than has been reported in other solvent systems. Still higher concentrations may be possible in particular cases by suitable variation in the solvent ratios Procedure 3 (section V) describes such a reduction of estradiol 3-methyl ether at a 0.12 M concentration. A few steriods such as the dimethyl and diethyl ketals of estrone methyl ether are poorly soluble in ammonia-tetrahydrofuran-/-buty] alcohol and cannot be reduced successfully at a concentration of 0.06 even with a 6 hour reduction period. The diethyl ketal of estrone methyl ether is reduced successfully at 0.12 M concentration using a two-phase solvent system of ammonia-/-amyl alcohol-methylcyclohexane (Procedure 4, section V). This mixture probably would be useful for any nonpolar steroid that is poorly soluble in polar solvents but is readily soluble in hydrocarbons. 

Mergence of the binodial with the nonsolvent-solvent axis shows that the polymer concentration in the more dilute phase becomes vanishingly small when the proportion of nonsolvent exceeds appreciably that at the critical point. These features clearly parallel those observed in two-component systems, with the nonsolvent-solvent ratio assuming the role of temperature in the latter. It may be shown that they are not critically dependent on the particular values assigned to the... 

Fig. 123.—(a) Phase diagram calculated for three-component systems consisting of nonsolvent [1], solvent [2], and polymer [3] taking Xi==X2=l and Xz equal to 10 (dashed curve), 100 (solid curve), and °° (dotted curve) xi2 = xi3 = 1.5 and X23 =0. All critical points (O) are shown and tie lines are included for the xs = 100 curve. (Curves calculated by Tompa. ) (b) The binodial curve for a 3 = 100 and three solvent ratio lines. The precipitation threshold is indicated by the point of tangency X for the threshold solvent mixture. 

Figure 11. Pore size distribution of palladium(II) EnCat 30 and palladium(II) EnCat 40 swollen in THF the materials differ in the isocyanate/solvent ratio in the microencapsulation mixture (see text), which was 30/70 and 40/60 (w/w), respectively. (Reprinted from Ref. [38], 2005, with permission from Reaxa Ltd.)...

The multicomponent mobile phase must not be used repeatedly because the volatility of solvents produces a continuous modification of the solvent ratio, which negatively affects the chromatographic results. 

Mixing, wrist shaking, or tumbling combinations offer a simple, effective, but time-consuming and not highly reproducible method of extraction. Sample-to-solvent ratios are similar to Soxhlet ratios. Although sample manipulation is reduced, this technique requires nearly as much time as the Soxhlet method. Shake-flask extraction is low cost. 

Frequently, however, the solubility curve has a maximum (as shown by circles in Fig. 2, when plotted as both a function of C2 and [10]. In either case it is possible to optimize solubility by selection of a solvent system with a given value of s that is, once the curve has been established, the optimum water/solvent ratio for another solvent can be calculated from known dielectric constant relationships [11],... 

Digestion 400°C, 60 minute residence time Coal Solvent ratio 1 4... 

Figure 5. Influence of digestion time and temperature on extraction yield. Coal = Beynon solvent = anthracene oil coal solvent ratio = 1 4.

It has been shown that the coal to solvent ratio has little influence upon the extraction yields when using coal concentrations in the range 10 to 50% (15). 

Digestion conditions 400°C 60 minute residence time Coal solvent ratio 1 3... 

The microautoclave solvent activity tests measure coal conversion in a small batch reactor under carefully controlled conditions. The tests are described as Kinetic, Equilibrium and SRT. The Kinetic and Equilibrium Tests measure coal conversion to tetrahydrofuran solubles at conditions where conversion should be monotonically related to hydrogen transfer. The Kinetic Test is performed at 399°C for 10 minutes at an 8 to 1 solvent to coal ratio. The combination of high solvent ratio and low time provide a measure of performance at essentially constant solvent composition. The measured conversion is thus related to the rate of hydrogen donation from solvent of roughly a single composition. In contrast, the Equilibrium Test is performed at 399°C for 30 minutes at a 2 to 1 solvent to coal ratio. At these conditions, hydrogen donors can be substantially depleted. Thus performance is related to hydrogen donor... 

If xi and X2 are the solute/solvent ratios in thickeners 1 and 2 respectively, then the mass balances are ... 

Assuming that equilibrium is attained, the solute/solvent ratio will be the same in the overflow and underflow products of each thickener and ... 

Figure 19. Change in concentration of Cl2CH-C60+ in H2SO+ p-toluenesulfonic acid of different solvent ratios.

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