Distillation three-component

FIG. 13-4 Distillation sequences for the separation of three components, a) Direct sequence, (h) Indirect sequence. 

An interesting variation of this reaction that made use of a three-component, one-pot solventless procedure with the corresponding trialkyl phosphites gave dramatically improved yields of many heterosubstituted glyphosate phosphonate diesters (37). When exactly one equivalent of water, 25, and tris-p-chloroethyl phosphite were mixed and heated under neat conditions for a few hours, nearly quantitative yields of displaced p-chloroethanol and the desired triester product 27 were obtained. If desired, the displaced alcohol was first removed by vacuum distillation, or the mixture could be hydrolyzed directly to GLYH3. Various oxygen, sulfur, nitrogen, cyano, and carboxylate functionalities were similarly accommodated in the trialkyl phosphite. 

Petlyuk FB and Avetyan VS (1971) Investigation of Three Component Distillation at Infinite Reflux, Theor Found Chem Eng, 5 499. 

The temperature of distillation is fixed by safety considerations at 410 K and, from a knowledge of the vapour pressures of the three components, the pressure in the still is found to be about 6 kN/m2. The composition of the vapour in the still is found from the relation yso = ce0xS0/T,axs. The liquid composition on the first plate is then found from equation (i) and for ortho ... 

Table 5,14 gives a digital computer FORTRAN program for this three-component batch distillation dynamic simulation. The specific example is a column with 20 trays and relative volatilities of 9, 3, and 1. The vapor flow rate is constant at 100 mol/h. 

When R2 substituent is flourocontaining alkyl group, the transformation 17 18 becomes hindered and its proceeding requires some special methods. For example, in [48] Biginelli-like cyclocondensations based on three-component treatment of 3-amino-l,2,4-triazole or 5-aminotetrazole with aldehydes and fluorinated 1,3-dicarbonyl compounds were investigated. It was shown that the reaction can directly lead to dihydroazolopyrimidines 20, but in the most cases intermediate tetrahydroderivatives 19 were obtained (Scheme 10). To carry out dehydration reaction, refluxing of tetrahydroderivatives 19 in toluene in the presence of p-TSA with removal of the liberated water by azeotropic distillation was used. The same situation was observed for the linear reaction proceeding via the formation of unsaturated esters 21. 

Isolation and spectral analysis of the dimer K-crotonate (100 g) was heated at 320 °C for 4 h and subsequently treated as described above. The methyl esters (42 g), bp 100-135 °C at 6mmHg, were fractionally distilled to give three components dimethyl hex-l-ene-3,4-dicarboxylate 1, bp 97 °C at 8 mmHg dimethyl 4-methyl-pent-2-ene-3,5-dicarboxylate 2, bp 118°C at 5 mmHg dimethyl 2-metliylene-3-methylbutyl-l,4-dicarboxylate 3, bp 129 °C at 8 mmHg. 

The superstructure for the illustrative example is shown in Figure 9.2. Note that we have two sequences of distillation columns (i.e., column 1 followed by column 2, and column 3 followed by column 4) since the feed stream has three components. In Figure 9.2, the potential process-process matches and the process-utility matches are indicated. The variables shown in Figure 9.2 are the unknown flow rates for the column sequences (i.e., F, F2,F3, F4) and existence variables for the columns (i.e., yi,y2, y3, Vi) and the process-process matches (i.e., yci,R2, yc2,Ri,yc3,R4, yc, R3)-The temperatures of the condensers and reboilers of each column, as well as the existence variables of the process-utility matches are not shown in Figure 9.2. 

Mori H., Ibuki R., Taguchi K., Futamura K., Olujic Z. Three-component distillation using structured packings Performance evaluation and model validation. Chem. Eng. Sci., Vol. 61, 1760-1766, 2006. 

Complex columns are distillation devices that can handle a mixture of minimum three components and deliver more than two products. A complex column consists of a main tower surrounded by additional columns, as prefractionator, side strippers and side rectifiers. As illustration, Figure 3.7 presents five alternatives for separating a ternary mixture ABC ... 

It is worth mentioning that a set of the types of the dynamic behavior of the system in the case of copolymerization of m monomers is principally wider in comparison with the distillation process of an m-component liquid mixture as it has already been remarked [13]. The reason for this lies in the fact that copolymerization is a non-equilibrium process in contrast to distillation. In a particular case of three-component copolymerization such a possibility is shown... 

The separation section required to achieve reactant recycle depends upon the relative volatilities of the three components. We consider two cases (1) the volatility of the product C is heavier or lighter than both of the reactants and (2) the volatility of the product C is intermediate between the reactants. In the first case, we need only one distillation column. In the second, we require two columns if we are limited to a simple two-product configuration. 

As a consequence of these restrictions, separation of binaiy mixtures by extractive distillation corresponds to onfy two possible three-component distillation region diagrams, depending on whether the binary mixture is pinched or close-boiling (DRD 001), or forms a minimumboiling azeotrope (DRD 003). The addition of high-boiling solvents... 

For the same feed, a batch stripper can be used to remove a bottoms product that approaches pure water. The pot composition (overhead) will contain all three components near the point of intersection of the distillation boundary with a straight line extended from the water vertex through the feed composition. 

The design of azeotropic or extractive distillation columns, as with con-A ventional columns, demands a knowledge of the vapor-liquid equilibrium properties of the system to be distilled. Such knowledge is obtained experimentally or calculated from other properties of the components of the system. Since the systems in azeotropic or extractive distillation processes have at least three components, direct measurement of the equilibrium properties is laborious and, therefore, expensive, so methods of calculation of these data are desirable. 

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