Reflux action

The residue was absorbed in 1,200 ml ethyl acetate, admixed with 20 ml ethanol and boiled for one hour under reflux action. The solution was filtered and compressed to dryness. The residue was dried in a vacuum drying cabinet. The yield amounted to 107.5 g. 

Reflux Experiments. More recent efforts have been directed at a quantitative evaluation of those parameters that affect polymer growth, namely acidity, plutonium concentration, temperature, and reflux action. The last is an interesting example to illustrate since the admission of low acid condensates or diluents to a Pu(IV) solution causes some polymer formation even when the bulk solution is otherwise acidic enough to prevent any measurable degree of hydrolysis. 

Alan Goldman developed much improved catalysts and also obtained detailed mechanistic information in the 1990s [35, 36]. An unexpected variant developed by Saito, by our own group and most extensively by Goldman, was acceptorless dehydrogenation. It turned out that the reaction could be driven by reflux because the hydrogen was continuously pumped out of the solvent by the reflux action [37-39]. 

Usually in an enricher or the enriching section of the membrane column, the more permeable component is steadily concentrated from the feed inlet to the compressor. However, some of the results show that the shell-side and even the tube-side composition profiles can pass through a minimum. Note the experimental data in Figures 7 and 8. In these cases the feed flow is relatively slow and reflux action, rather than bulk flow, is predominant. Figure 8 Illustrates that a composition minimum can also occur dinring operation of the total column when the residue flow rate from the enriching section is too slow. 

To get higher purity permeate, the product from the first stage can be compressed and sent to a second stage, as shown in Fig. 26.11c. Two or more stages could be used in this fashion to get the desired purity, but the cost of recompression and the increased complexity of the system makes this scheme generally uneconomical. A novel approach that uses two separators and one recompression step is the continuous membrane column. As shown in Fig. 26.1 Irf, part of the permeate product from the second separator is compressed and sent back to the other side of the membrane, where it flows countercurrently to the permeate. This reflux action permits very high purity permeate to be obtained. The reflux steam loses the more permeable component as it flows through the separator and is combined with the feed to the first separator. This scheme was demonstrated in pilot units but has not yet been used commercially. 

The mechanism of the sodium reduction reaction is principally via the vapour phase, since the sodium tends to be volatile (b.p. 883°C) and to be boiling xmder reflux during the reaction. This reflux action of the sodium tends to wash the reactor walls free of titanium metal and sodium chloride, so that the disposition of sponge, after completion of a reaction, is different from that in the magnesium process. 

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