Without Reflux

Figure 8. In-situ UV-Vis spectra during the formation of PVP-protected AuPt (1 1) bimetallic system in the region of l<350nm (a) and 1>350 nm (b). (a) Sampling from the solution of the metal ions in ordinary conditions for preparation at 100 °C with refluxing (b) the solution of the metal ions in a quartz UV cell was heated up to 80 °C without refluxing. (Reprinted from Ref [53], 1993, with permission from Elsevier.)...

So a compromise was reached (Fig. 856). Since you ll probably do more extractions than additions, with or without reflux, the pressure-equalizing tube went out, but the ground glass joint stayed on. Extractions no problem. The nature of the stem is unimportant. But during additions, you ll have to take the responsibility to see that nasty vacuum buildup doesn t occur. You can remove the stopper every so often or put a drying tube and inlet adapter in place of the stopper. The latter keeps moisture out and prevents vacuum buildup inside the funnel. 

A mixture of hydrocarbons A, B, C and D is charged to a batch still and is distilled over without reflux. 

It may be found advantageous to replace or supplement one or more of the lower stages of a separation system with a stabilizer tower. A stabilizer is a fractionator, operating either with or without reflux, and may be of various degrees of efficiency. The number of trays and height is limited by the platform configuration, but towers with 20-30 trays are feasible on many offshore platforms. 

The rectification of tetraethyltin is carried out in vacuum. Before rectification the whole system is pressurised with nitrogen (at atmospheric pressure) cooler 11 is filled with water, freezer 12 is filled with salt solution after that, the tank receives the solution of tetraethyltin from reactor 5. The vacuum pump is switched on when the residual pressure in the system is 50-70 GPa, benzene is distilled and collected in the freezer. After the distillation is over, the jacket of the tank is filled with vapour. Until the temperature in the vapours is constant, the tower operates without refluxing. After constant temperature has been established, the first fraction is separated into receptacle 13. This fraction (a mixture of tin ethyl bromides) is separated below 54 °C (at a residual pressure of 50-70 GPa) the target fraction, tetraethyltin, is separated above 54 °C into receptacle 14. 

What product compositions would be obtained a. without reflux, or... 

The relative volatility of W with respect to P is so large that it can be considered to be capable of being separated without reflux. 

Separate the Cj cut first use distillation without reflux and without the temperatures that might cause CO2 freezing. Do not use a solvent in the first column. This allows more CO2 to go overhead and the latter is lost by scrubbing the methane to free it from the CO2. The bottoms is sent to an extractive distillation column. Figure 23a shows the variation. This option is sho Miin Fig. P-23a. 

For example, addition of 1,3-dibromopropane to the THF solution of 8 at — 78"C formed the intermediate 9a, which cyclized, when warmed to room temperature, to yield 1-methyl-l-(l-methylethenyl)cyclopentane 13 [11]. On the other hand, an acidic workup of 9a at — 35 C gave a single monoalkylated product, 6-bromo-2,3,3-trimethyl-l-hexene 12, in 72% isolated yield. Similar chemistry was observed with 1,4-dibromobutane, except that no cyclization would occur without refluxing conditions. Interestingly, the cyclization of 9a to 13 represents a cross-coupling of an organomagnesium reagent with an alkyl bromide, which is normally observed only in the presence of certain transition metal salts or complexes [12]. 

FIG. 15-7 Dual-solvent fractional extraction without reflux. 

The second type of fractional extraction operation involves the use of stripping and washing sections without reflux (Fig. 15-7) to separate a mixture of feed solutes with close K values. In this case, the solute separation factor is low to moderate. Normally, must be greater than about 4 for a commercially viable process. Scheibel [Chem. Ene. Prog., 44(9), pp. 681-690 (1948) and 44(10), pp. 771-782 (1948)] gives several... 

Minimum reflux corresponds to the overlap of an operating line and a tie-line (infinite stages at a pinch point). This concept is similar to minimum solvent flowrate for an extraction process without reflux. Total reflux corresponds to the minimum number of stages. Remember that total reflux means that no streams are going into or out of the column, so that F, B, and D are zero, and A = A. ... 

Quinoline in an equal volume of ether added to a stirred suspension of phenyl-MgBr in ether-dioxane, stirring without refluxing continued 48 hrs. -> 2-phenylquinoline. Y 44%.—Without dioxane a yield of ca. 7.5% is obtained, and with addition of phenyl-Li a yield of 58.5%. (H. Gilman and G. C. Gainer, Am. Soc. 71, 2327 (1949).)... 

FIGURE 7-3-4 Triangular diagram for extraction without reflux. 

FIGURE 7.3-5 Distribution diagram for extraction without reflux, as le Fig. 7.3-1. showing both the operating and equilibrium curves. 

Handbook of Industrial Membrane Technology Cascades Without Reflux... 

Such cascades are only sensible in cases where the retentate is practically worthless. Norsk-Hydro, for example, is operating an electrolysis-heavy-water-production-plant where the deuterium is separated in a cascade without reflux (at least in the lower part of the cascade). Figure 6.14 illustrates the principle of a cascade without reflux. 

Analyze countercurrent extraction cascades without reflux. 

This is the well-known Rayleigh equation, as first applied to the separation of wide-boiling mixtures such as HCI-H2O, H2S0 -H20, and NHJ-H2O. Without reflux, yp and Xw are in equilibrium and (9-2) can be written as ... 

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