Distilling adapter

The dotted line in Fig. 11,17, 2 refers to the modification of the apparatus for use in fractional distillation under reduced pressure a Perkin triangle or equivalent receiver device ( vacuum distilling adapter ) is generally employed for collection of the various fractions. 

Attach the flask containing the mixture, with capillary in position, to the column make sure that the Perkin triangle (or vacuum distilling adapter ) and receiver are in place. See that the oil pump is functioning... 

The distillation should be carried out carefully at first until all the chloroform has distilled. A distilling adapter dipping just below the surface of the acid solution should be used in order to minimize loss of cyclobutylamine. Care must be taken that the basic solution in the distillation flask which still contains sodium azide does not come in contact with the hydrochloric acid solution in the receiver. 

Figure 9.12 Total and maximum reflux in binary distillation. (Adapted from Smith R and Jobson M, 2000, Distillation, Encyclopedia of Separation Science, Academic Press reproduced by permission).

In a 3-1. round-bottomed three-necked flask fitted with an efii-cient mechanical stirrer, a reflux condenser, and a thermometer are placed 170 g. (1.2 moles) of phosphorus pentoxide, 187 g. (2 moles) of chloroacetamide (Note 1), and 800 ml. of dry technical trimethylbenzene (Note 2). The mixture is refluxed gently with vigorous stirring for 1 hour. The reaction mixture is then allowed to cool to about 100° with continuous stirring, and the reflux condenser is replaced with a distilling adapter fitted with a thermometer and a water-cooled condenser. 

The vacuum distillation adapter also shown in Fig. 2.106 allows the collection of fractions when distilling under reduced pressure. Its operation is similar to the Perkin triangle or equivalent device ( intermediate receiver adapter ) described in Section 2.27. The general technique of conducting a fractional distillation is as follows ... 

The submitters used a 500-ml. distilling flask with a 250-ml. distilling flask as receiver. The side arm of the distilling flask was extended, if necessary, by means of a Tygon joint into the bulb of the receiver. The receiver was cooled by a stream of cold water. The distillation was continued until about three-fourths of the material in the flask had distilled. The checkers used standard-taper glassware for the distillation they found it necessary to heat the distillation adapter with a microburner from time to time in order to prevent plugging by solidified product. They continued the distillation until no further solid product distilled. 

Plastic joint chps or Keck clips (Fig. 5.22a) are used for holding ground-glass joints firmly together and may be used to replace clamps and support stands at certain points when building apparatus (see p. 109) and are essential when using rotary evaporators (p. 122). The main weakness of these otherwise useful devices is that they soften at about 130°C and this may allow the joints to separate. Therefore they should never be used at the hot end of a distillation, for example. The clip should be used to hold a distillation adapter on the end of a water condenser, or the flasks onto a fraction collector, but never on the distilling flask or to hold the condenser onto the still head (Fig. 5.22b). 

Hence, a prepolymer of poly(hexamethylene carbonate) was formed by adding to a flame dried 250 ml single neck flask 36.6 g of 1,6-hexanediol and 69.2 g of diphenyl carbonate. The flask was fitted with a mechanical stirrer, a distillation adapter and recehing flask. The reaction flask was held under high vacuum at room temperature... 

Figure 1.7 Piping and Instrumentation Diagram for Benzene Distillation (adapted from Kauffman, D, Flow Sheets and Diagrams, AIChE Modular Instruction, Series G Design of Equipment, series editor J. Beckman, AIChE, New York, 1986, vol 1, Chapter G.1.5, AIChE copyright 1986 AIChE, all rights reserved)...

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