Condensation temperature

In acidic medium and at higher temperatures, condensation of 2-amino-4-phenylthiazole takes place when it reacts with benzaidehyde... 

When an atom or molecule receives sufficient thermal energy to escape from a Hquid surface, it carries with it the heat of vaporization at the temperature at which evaporation took place. Condensation (return to the Hquid state accompanied by the release of the latent heat of vaporization) occurs upon contact with any surface that is at a temperature below the evaporation temperature. Condensation occurs preferentially at all poiats that are at temperatures below that of the evaporator, and the temperatures of the condenser areas iacrease until they approach the evaporator temperature. There is a tendency for isothermal operation and a high effective thermal conductance. The steam-heating system for a building is an example of this widely employed process. 

The Madelung Synthesis and Related Base-Catalyzed Condensations. The Madelung cyclization involves an intramolecular condensation of an o-aLkylanilide. A classic example of the Madelung synthesis is the high temperature condensation of o-methylacetanihde [120-66-1] to 2-methylindole [95-20-5] by sodium amide. 

Of the four commercial processes for the purification of carbon monoxide two processes are based on the absorption of carbon monoxide by salt solutions, the third uses either low temperature condensation or fractionation, and the fourth method utilizes the adsorption of carbon monoxide on a soHd adsorbent material. AH four processes use similar techniques to remove minor impurities. Particulates are removed in cyclones or by scmbbing. Scmbbing also removes any tars or heavy hydrocarbon fractions. Acid gases are removed by absorption in monoethanolamine, hot potassium carbonate, or by other patented removal processes. The purified gas stream is then sent to a carbon monoxide recovery section for final purification and by-product recovery. 

If the vapor is superheated at the inlet, the vapor may first be desuperheated by sensible heat transfer from the vapor. This occurs if the surface temperature is above the saturation temperature, and a single-phase heat-transfer correlation is used. If the surface is below the saturation temperature, condensation will occur directly from the superheated vapor, and the effective coefficient is determined from the appropriate condensation correlation, using the saturation temperature in the LMTD. To determine whether or not condensation will occur directly from the superheated vapor, calculate the surface temperature by assuming single-phase heat transfer. 

A. 6-Chloro-2-hexyne. A 2-1., three-necked, round-bottomed fiask is equipped with a low-temperature condenser (Note 1), a gas inlet, and a... 

Gases or vapours that are not water soluble but are slowly reactive, with absorbing agent Condensation Freezing traps or low temperature condensers Glass or metal Dry 1-5 90-100 (depends on vapour pressures at reduced temperature) Can be packed with glass beads or other extended surfaces... 

Two-part room temperature condensation cure. Silicone can be formulated into two-part systems [3,12,14,33] that prevent the reactive groups from coming into contact before they are needed. The reactions in these systems are based on the condensation of a silanol group with an alkoxy silane group, catalyzed by organo-tin compounds (Scheme 9). 

By adjusting the Jacket temperatures, condensation or polymerization can be avoided inside the pump. The volume handled Figure 6-40 is often expressed as free air, CFM. This is simply the mechanical displacement of the pumping volume of the unit for the particular driven speed of the unit. 

Maximum temperature condenser water in, °F = 85 Steam consumption, booster, Ib/hr = 4,150... 

Where high temperatures are required (e.g. for process work) and lower temperatures for space heating, it is desirable to use flash steam recovery from the high-temperature condensate to feed into the low-temperature system, augmented as required by reduced pressure live steam. 

The distance of D between the two parts of the curve indicates the proportion of flash gas at that point. The condenser receives the high-pressure superheated gas, cools it down to saturation temperature, condenses it to liquid, and finally suhcools it slightly. The energy removed in the condenser is seen to he the refrigerating effect plus the heat of compression. 

The separated ammonia and hydrogen fluoride can be condensed and collected in the form of NH4F or NHtHF2 according to temperature condenser. 

Low temperature condensation of high temperature species as a synthetic method. P. L. Timms, Adv. Inorg. Chem. Radiochem., 1972,14,121-171 (143). 

Photosensitive functions are in many cases also heat sensitive, so the preparation of photosensitive polyimides needs smooth conditions for the condensations and imidization reactions. Some chemical reactants, which can be used for polyamide preparation, have been patented for the synthesis of polyimides and polyimide precursors. For example, chemical imidization takes place at room temperature by using phosphonic derivative of a thiabenzothiazoline.102 A mixture of N -hydroxybenzotriazole and dicyclohexylcarbodiimide allows the room temperature condensation of diacid di(photosensitive) ester with a diamine.103 Dimethyl-2-chloro-imidazolinium chloride (Fig. 5.25) has been patented for the cyclization of a maleamic acid in toluene at 90°C.104 The chemistry of imidazolide has been recently investigated for the synthesis of polyimide precursor.105 As shown in Fig. 5.26, a secondary amine reacts with a dianhydride giving meta- and para-diamide diacid. The carbonyldiimidazole... 

Two-shot techniques for acyclic diene metathesis, 435-445 for polyamides, 149-164 for polyimides, 287-300 for polyurethanes, 241-246 for transition metal coupling, 483-490 Anionic deactivation, 360 Anionic polymerization, 149, 174 of lactam, 177-178 Apolar solvents, 90 Aprotic polar solvents, 185, 338 Aprotic solvents, low-temperature condensation in, 302 Aqueous coating formulations, 235 Aqueous polyoxymethylene glycol, depolymerization of, 377 Aqueous systems, 206 Ardel, 20, 22... 

High-temperature bulk reactions, 63 High-temperature condensation, in cresolic medium, 302... 

Low Temperature Condensation of High Temperature Species as a Synthetic Method P. L. Timms... 

Freezing traps or low temperature condensers Glass or metal... 

Solvent venting, without splitting Liquid sample from syringe into cold inlet. Solvent is vented at low temperature, condensing nonvolatiles. Heat programming subsequently vaporises the residues, which enter column as in splitless injection Dilute samples thermally labile Broad, some focusing required 1-1000 80-95... 

The low-temperature condensation requires refrigeration, for which the cost is given by ... 

Low-temperature/high-pressure distillation. Rather than use a low-temperature single-stage condensation or refluxed condenser, a conventional distillation can be used. To carry out the separation under these circumstances will require a low-temperature condenser for the column, or operation at high pressure, or a combination of both. 

Recently Sergeev et al. 90 91> have developed a low temperature condensation method for the formation of inclusion compounds of thiourea with reactive and volatile guests, avoiding the use of solvents. The two guests in the joint inclusion compound of thiourea with 1,3-cyclopentadiene and maleic anhydride underwent Diels-Alder addition at 170 K. These two substances do not react at this low temperature unless they are present in the thiourea complex the usual endo isomer of the product is formed. Apart from copolymerisation reactions this appears to be the first use of the thiourea canal to study reactions between different materials. 

Kryoclean A process for removing volatile organic compounds from effluent gas streams by low-temperature condensation. The refrigerant is liquid nitrogen, used subsequently in various ways. Developed by BOC in the 1990s. A simplified version of the process was announced in 1997. 

The observed range of natural variations of 5 Ca is about 4 to 5%o in terrestrial materials and up to 50%o in high temperature condensate minerals in carbonaceous chondrites. The typical reproducibility of measurements is about +0.15%o. Broader application of Ca isotope measurements in geochemistry may be possible, particularly if the reproducibility can be improved to 0.05%o to 0.03%o. There is hope that this can be achieved either with inductively coupled plasma source mass spectrometry (Halicz et al. 1999) or with a new generation of multi-collector thermal ionization mass spectrometers (Heuser et al. 2002). 

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