Flash distillation equipment required

This is a process mainly used in power plants for separation of dissolved matters by evaporation of the water. Multistage flash distillation, multiple-effect vertical long-tube vertical evaporation, submerged tube evaporation, and vapor compression are effective process equipment. It may require pH adjustment. The process removal efficiency is about 100%. 

In view of the quantities of benzene (CAUTION) required, the entire preparation must be carried out in the fume cupboard. Place a mixture of 125 ml of pure benzene and 32.5 g (0.123 mol) of dibutyl ( + )-tartrate (1) in a 500-ml threenecked flask, equipped with a Hershberg stirrer (Fig. 2.49) and a thermometer. Stir the mixture rapidly and add 58 g (0.13 mol) of lead tetraacetate (Section 4.2.45, p. 441) in small portions over a period of 20 minutes while maintaining the temperature below 30 °C by occasional cooling with cold water. Continue the stirring for a further 60 minutes. Separate the salts by suction filtration and wash with two 25 ml portions of benzene. Remove the benzene and acetic acid from the filtrate by flash distillation and distil the residue under diminished pressure, preferably in a slow stream of nitrogen. Collect the butyl glyoxylate (2) at 66-69 °C/5mmHg. The yield is 26g (81%). 

As stated earlier, distillation is a widely used separation technique for liquid mixtures or solutions. The formation of these mixtures is straightforward, and is usually spontaneous, but the separation of a mixture into its separate constituents requires energy. One of the simplest distillation operations is flash distillation. In this process, part of the feed stream vaporizes in a flash chamber, and the vapor-liquid mixture, which is at equilibrium, is separated. The vapor is rich in the more volatile component, but complete separation is usually not achieved. A simple schematic showing the necessary equipment for flash distillation is given in Figure 10.3. We will illustrate the concepts by using a simple case of the flash distillation of a binary mixture. 

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