Condenser multicomponent

The most atom-economy-suited reactions are condensations, multicomponent reactions, and rearrangements. Hence, where possible, these reaction types should be adopted, in order to ensure... 

For multicomponent vapor-liquid equilibria, the equation of equilibrium for every condensable component i is... 

The shape of the coohng and warming curves in coiled-tube heat exchangers is affected by the pressure drop in both the tube and shell-sides of the heat exchanger. This is particularly important for two-phase flows of multicomponent systems. For example, an increase in pressure drop on the shellside causes boiling to occur at a higher temperature, while an increase in pressure drop on the tubeside will cause condensation to occur at a lower temperature. The net result is both a decrease in the effective temperature difference between the two streams and a requirement for additional heat transfer area to compensate for these losses. 

Example 10 Calculation of Multicomponent Batch Distillation A charge of 45.4 kg mol (100 Ih-mol) of 25 mole percent heuzeue, 50 mole percent monochlorohenzene (MCB), and 25 mole percent orthodichloro-henzene (DCB) is to he distilled in a hatch still consisting of a rehoiler, a column containing 10 theoretical stages, a total condenser, a reflux drum, and a distillate accumulator. Condenser-reflux drum and tray holdups are 0.0056 and... 

Braun, M., and Renz, U., Investigation of Multicomponent Diffusion Models in Turbulent Flow, Procc. Engineering Foundation Conf. on Condensation and Condenser Design, pp81- 92, 1993. 

Total reflux exists in a distillation column, whether a binary or multicomponent system, when all the overhead vapor from the top tray or stage is condensed and returned to the top tray. Usually a column is brought to equilibrium at total reflux for test or for a temporary plant condition which requires discontinuing feed. Rather than shut down, drain and then re-establish operating conditions later, it is usually more convenient and requires less... 

In some operations, where the top product is required as a vapour, only sufficient liquid is condensed to provide the reflux flow to the column, and the condenser is referred to as a partial condenser. When the liquid is totally condensed, the liquid returned to the column will have the same composition as the top product. In a partial condenser the reflux will be in equilibrium with the vapour leaving the condenser. Virtually pure top and bottom products can be obtained in a single column from a binary feed, but where the feed contains more than two components, only a single pure product can be produced, either from the top or bottom of the column. Several columns will be needed to separate a multicomponent feed into its constituent parts. 

When the condensation process is not exactly isothermal but the temperature change is small such as where there is a significant change in pressure, or where a narrow boiling range multicomponent mixture is being condensed the logarithmic temperature difference can still be used but the temperature correction factor will be needed for multipass condensers. The appropriate terminal temperatures should be used in the calculation. 

Total condensation of a multicomponent mixture such as the overheads from a multicomponent distillation. 

Condensation of only part of a multicomponent vapour mixture, all components of which are theoretically condensable. This situation will occur where the dew point of some of the lighter components is above the coolant temperature. The uncondensed component may be soluble in the condensed liquid such as in the condensation of some hydrocarbons mixtures containing light gaseous components. 

Integral condensation in which the liquid remains in equilibrium with the uncondensed vapour. The condensation curve can be determined using procedures similar to those for multicomponent flash distillation given in Chapter 11. This will be a relatively simple calculation for a binary mixture, but complex and tedious for mixtures of more than two components. 

Bell, K. J. andGHALY, M. A. (1973) Chem. Eng. Prog. Symp. Ser. No. 131, 69,72. An approximate generalized design method for multicomponent/partial condensers. 

For multicomponent condensation, the condensation will not be isothermal, leading to a nonlinear temperature-enthalpy profile for the condensation. If this is the case, then the exchanger can be divided into a number of zones with the temperature-enthalpy profiles linearized in each zone. Each zone is then modeled separately and zones summed to obtain the overall area requirement1. 

Recently, a new multicomponent condensation strategy for the stereocontrolled synthesis of polysubstituted tetrahydropyran derivatives was re-published by the Marko group, employing an ene reaction combined with an intramolecular Sakurai cyclization (IMSC) (Scheme 1.14) [14]. The initial step is an Et2AlCl-promoted ene reaction between allylsilane 1-50 and an aldehyde to afford the (Z)-homoallylic alcohol 1-51, with good control of the geometry of the double bond. Subsequent Lewis acid-media ted condensation of 1-51 with another equivalent of an aldehyde provided the polysubstituted exo-methylene tetrahydropyran 1-53 stereoselectively and... 

A combination of a multicomponent Ugi transformation and an intramolecular Diels-Alder reaction has been developed by Paulvannan [13]. Hence, condensation of the resin-bound (acid-labile ArgoGel-Rink resin) amine 10-37 with a tenfold... 

In a further example of a multicomponent synthesis, dihydrobenz[/] 1,4 oxazepin-5-ones were prepared in good yields in two steps by combining an initial three-component Ugi condensation with a subsequent Mitsunobu cyclisation to give (124 e.g. R1 = H, R2 = i-Pr, R3 = cyclohexyl, 65%) <06OBC4236>. 

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