Distillation constant

Mix 30 g. (38 ml.) of iaopropyl alcohol with 450 g. (265 ml.) of constant boiling point hydriodic acid (57 per cent.) (Section 11,49,2) in a 500 ml. distilling flask, attach a condenser for downward distillation, and distil slowly (1-2 drops per second) from an air bath (compare Fig. II, 5, 3). When about half the liquid has passed over, stop the distillation. Separate the lower layer of crude iodide (80 g.). Redistil the aqueous layer and thus recover a further 5 g. of iodide from the flrst quarter of the distillate (1). Wash the combined iodides with an equal volume of concentrated hydrochloric acid, then, successively, with water, 5 per cent, sodium carbonate solution, and water. Dry with anhydrous calcium chloride and distil. The isopropyl iodide distils constantly at 89°. 

Reflux 1 ml. of the ether with 5 ml. of freshly distilled, constant boiling point hydriodic acid (Section 11,49,2), b.p. 126-128°, for 2-3 hours. Add 10 ml. of water, distil and collect about 7 ml. of liquid. Decolourise the distillate by the addition of a httle sodium bisulphite, and separate the two layers by means of a dropper pipette (Fig. 11,27,1). Determine the b.p. of the resulting iodide by the Siwoloboff method (Section 11,12) and prepare a crystalline derivative (Section 111,42). 

Simple Batch Distillation Constant a, with Trays or Packing, Constant BoUup, and with Reflux [129] Using x-y Diagram... 

Example 8-14 Batoh Distillation, Constant Reflux Following the Procedure of Block [133]... 

Batch with Constant Reflux Ratio, 48 Batch with Variable Reflux Rate Rectification, 50 Example 8-14 Batch Distillation, Constant Reflux Following the Procedure of Block, 51 Example 8-15 Vapor Boil-up Rate for Fixed Trays, 53 Example 8-16 Binary Batch Differential Distillation, 54 Example 8-17 Multicomponent Batch Distillation, 55 Steam Distillation, 57 Example 8-18 Multicomponent Steam Flash, 59 Example 8-18 Continuous Steam Flash Separation Process — Separation of Non-Volatile Component from Organics, 61 Example 8-20 Open Steam Stripping of Heavy Absorber Rich Oil of Light Hydrocarbon Content, 62 Distillation with Heat Balance,... 

Alternatively, by careful control of the reflux ratio, it is possible to hold the composition of the distillate constant for a time until the required reflux ratio becomes intolerably large, as illustrated in Figure 14.9. A mass balance gives ... 

Figure 11.35. Batch distillation-constant product composition...

Figure 11.37. Batch distillation-constant reflux ratio (Example 11.13)...

TABLE 5.2 Comparing Results for Simple Distillation, Constant Reflux Ratio, and... 

The hydrobromic acid used was twice-distilled, constant-boiling acid. Triplicate gravimetric analyses of the stock solution of aqueous HBr (about 3M) agreed to within 0.01%. The tetraethylammonium bromide (Eastman Kodak Co.) was recrystallized twice from benzene-ligroin mixtures, as recommended by Unni et al. (18). The molality of the stock solution (about AM) was standardized by gravimetric determination of bromide and was accurate to within 0.02%. 

Rgure 8-35. Batch distillation constant reflux ratio after McCabe-Thlele diagram. Revised/adapted and used by permission, Schweitzer, PA Handbookaf Separation Techniques for Chemical Engineers, McGraw-Hill Book Co. (1979) also reprinted by special permission, Chem. Eng. Jan. 23 (1961), p. 134., 1961 by McGraw-Hill, Inc., New York. 

In a binary batch distillation process with no reflux (differential distillation), constant relative volatility is assumed throughout the process, a = 2. If the initial liquid composition X° = 0.4, what is the initial distillate composition What is the composition of the liquid remaining in the boiler when 50% of the original liquid has been distilled When 99% has been distilled ... 

Table 1. Changes of outlet sulphur level depending on end of distillation (constant inlet sulphur 430 ppm)...

Aqueous hydriodic acid is formed when H2S is led into a vigorously stirred suspension of iodine (120 g) in water (150 ml) until the iodine color is almost completely discharged. The solution is filtered from the sulfur formed, boiled for removal of H2S, and distilled. Constant-boiling hydriodic acid (b.p. 126.56/760 mm d 1.70) contains 56.7% of HI. Aqueous HI that has become brown owing to liberation of iodine can be decolorized by treatment when hot with 50% hypophosphorous acid (H3P02).5i... 

On the other hand, calculation of diffusion in distillation columns tends to be easier if the molar average reference velocity v gf moi is used. In distillation, constant molal overflow is often valid or close to valid fSection 4.2T The resulting equimolar counterdiffusion results in = -Ng, and there is no convection in the reference frame with v,.pf mni = 0. If we choose the reference velocity as the molar average velocity, then Eq. ri5-16ei becomes... 

Although freshly distilled constant-boiling acid is recommended, its concentration is not critical. Thus, the bromide has been prepared satisfactorily using 68.8 ml. of 40 per cent hydrobromic acid (d. 1.38). Similarly, the iodide has been formed using 87 ml. of 47 per cent hydriodic acid (d. 1.60). 

Preparation from 2-amino-2 -hydroxy-4-methoxy-4 -nitrobenzophenonebyreflux-ing with freshly distilled constant-boiling hydriodic acid at 140° for 7 h (63%) [286]. 

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