Condensing action

The add is obtained by the reduction of cinnamic acid by means of sodium amalgam. The acid is then esterified by the condensing action of a mineral acid in methyl alcohol solution. The ester is an oil of very sweet odour, and is very useful for flower bouquets. 

Reaction XXVI. (a) Condensing Action of Potassium Cyanide, Potassium Carbonate, or other substances on Aliphatic (Claisen) and Aromatic Aldehydes (Liebig). (J. C. S., 117, 324.)—With aliphatic and aromatic aldehydes this condensation follows very different lines. In the former the condensation takes place between the aldehydic carbon of one molecule and the a-carbon of another molecule. The same or different aldehydes may be used. 

Reaction XXVI. (b) Condensing Action of Potassium Cyanide on a Mixture of an Aliphatic Aldehyde and a Ketone. (A., 306, 324.)—This is a reaction similar to the previous, a ketone and an aldehyde being condensed to give a 1 3-ketol. 

In 1930, Blagoveschenski claimed66 the synthesis of raffinose by the condensing action of almond emulsin on a mixture of sucrose and D-galac-tose. The small amount of product (which had [o]d + 95.66°) was hydrolyzed by emulsin, and may have been at least partly raffinose, but the work should be repeated, using a more definitive test for raffinose. 

Pawlowski and Schartel92 have added 1 or 5 wt % of boehmite to blends of PC/ABS with PTFE and RDP or bisphenol A bis(diphenylphosphate). The release of water from AlOOH influences the decomposition of the material by enhancing the hydrolysis of PC and RDP. Consequently, the condensed action of RDP or BDP is perturbed. The reaction of the arylphosphate with boehmite replaces both the formation of anhydrous alumina and alumina phosphate on the one hand, and the cross-linking of arylphosphate with PC on the other hand, since less phosphate is available to perform condensed-phase action. The reaction with arylphosphate therefore decreases the char formation, but the formation of aluminum phosphate could enhance barrier properties. On the whole, even high levels of fire retardancy can be achieved (V-0 ratings) the combination of boehmite with arylphosphates acting in the condensed phase seems very complex, particularly when the host polymer can undergo hydrolysis reactions due to water release. 

Special heat-transfer devices used to liquefy vapors by removing their latent heats are called condensers. The latent heat is removed by absorbing it in a cooler liquid called the coolant. Since the temperature of the coolant obviously is increased in a condenser, the unit also acts as a heater, but functionally it is the condensing action that is important, and the name reflects this fact. Condensers fall into two classes. In the first, called shell-and-tube condensers, the condensing vapor and coolant are separated by a tubular heat-transfer surface. In the second, called contact condensers, the coolant and vapor streams, both of which are usually water, are physically mixed and leave the condenser as a single stream,... 

Phosphorus oxychloride may be used in place of zinc chloride, and this is recommended for cases where the latter has not sufficient condensing action owing to the low solubility of its amine adduct.884 Boron trifluoride etherate was found to be a particularly active catalyst for condensation of 9-fluorenone with aromatic amines.885... 

Reverse flow of vapor from the column into the reflux line would interfere with liquid downflow, condenser action, and may cause hammering if the reflux is subcooled. A seal loop (Fig. 5.1a to c) is almost always used to avoid reverse flow. The low point in the seal loop needs a drain (normally closed). 

Lines for introducing the feed at the reboiler inlet sump These lines are useful for avoiding excessive temperatures at the column bottom. When column heating is performed solely by reboil action, they can also speed up column heating (i.e., they eliminate the condensing action of a cold feed in the bottom section). 

Either tjrpe of pinching can also be alleviated by increasing the heating medium temperature or by injecting sparge gas such as nitrogen at the reboiler bottom. Sparge gas iiyection, however, may adversely affect overhead condenser action or top product purity. 

Figure 17.7e shows column pressure control by adjusting column boilup. This method is complex, but it has worked smoothly in some instances (234). Either a flooded or a nonflooded reflux drum can be used in the latter case, reflux drum level can regulate the rate of condenstaion. Bottom flow is regulated by the bottom sump level. This method may be beneficial in some stripping columns receiving subcooled feeds, where feed temperature variations can affect column pressure to a larger extent than overhead condenser action. 

Fig. 13. Vacuolation phenomena with oleate coacervates, in which the agent is added (4 ) or removed ( ) via the vapour phase, a The agent has a condensing action on the coacervate. b The agent has a swelling action on the coacervate.

With suitable coacervate objects one may observe that currents " occur in coacerv-ate drops restit on a starched microscope slide (p. 435) when a sufficiently stroi dif-fusionfield is produced, in the equilibrium liquid, of a substance which makes the coacervate richer in colloid (" condensing action). It then appears that the surface of the drop moves towards the side where this condensation (with possibly local form ation of small vacuoles as a consequence) is the most pronounced. As a consequence of this the whole contents of the coacervate drop are set in motion as can be seen from the motion of the vacuoles transported with it (Fig. 19a). 

I B. Only a vacuole field is produced, thus in this case a weaker condensing action. Examples phenanthrene, p-dichlorobenzene and isobutyl urethane. 

I C. First we see vacuoles produced around the crystal. This appears however to be a ring of vacuoles which slowly shifts. The crystal finally lies in a clear zone. In this case we must assume that low concentrations of the compound investigated have a condensing action, higher concentrations on the other hand an opening action — in the sense of favouring water-uptake. Examples propylurethane and hydroquinone. 

II E. On warming a somewhat larger number of vacuoles are produced round the crystal than further out in the preparation. This indicates a weak condensing action, which was not observable at room temperature. On cooling the vacuoles around the crystal disappear the last, or they continue to exist. Example anthracene. 

There is a disadvantage connected with this method. It is difficult to compare the actions of various compounds with each other because the solubility in the coacer-vate plays a great part. If a substance has no influence then this may certainly also be attributed to the insolubility of that substance. Thus the action of aromatic hydrocarbons decreases in a manner parallel to the increase of the boiling point. Does this in fact mean that the condensing action decreases in this direction This seems improbable. The decrease — in the same direction — of the solubility is likely to be the explanation of the observed facts. 

The condensing action of the hydrocarbon chain increases with the length. With an equal number of carbon atoms the influence decreases with branching... 

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