Fully-automatic apparatus

The latest development in the field of low-temperature distillation is illustrated by the fully automatic apparatus of Podbielniak. The Thennocon model, series... 

In continuous processes at least two adsorbers are used in parallel (adsorption, desorption). Because of the complicated operation, fully automatic apparatus is preferred (Figure 2.3.6-1). 

Although excellent results may frequently be obtained by fractional extraction with such simple equipment as a set of separating funnels, still more efficient separations may be effected when more elaborate apparatus is used. There is commercially available a fully automatic equipment, named after Craig, which is so designed that several transfers occur simultaneously in a train of contacting tubes. There are counter-current instruments containing from a few dozen tubes up to 1000 or more. 

Protein and nucleic acid syntheses are fully automatized procedures nowadays. Detailed instructions come with commercial apparatus. Problems that only an organic chemists can solve only occur if the biopolymers are needed in large quantitities. 

In practically all modem apparatus for laboratory distillation certain functions are now automatic. Heating is often controlled by contact thermometers, and the rate of evaporation of the charge with differential manometers. Reduced pressures are also frequently kept constant with automatic units. In fact, the present trend is towards fully automatic control of the conditions of distillation and simultaneous recording of the data measured, an object that has already been reached in many industrial installations. The ideal procedure is for the mixture to be merely introduced into the apparatus and the latter switched on it then automatically yields the required products of distillation and at the same time prepares a diagram of the top and bottom temperatures and other data that may be needed. 

Basically, any apparatus for batch or continuous distillation may be automated to such an extent that it may be called fully automatic. A fuUy automatic apparatus was developed by Ulusoy [8] especially for preparative work. In the section on low-temperature distiUation, a fuUy automatic apparatus due to Podbielniak was mentioned (Fig. 178) the block diagram of which is given in Fig. 360. A number of... 

Block diagram of the fully-automatic low-temperature apparatus Thermocon (Podbiel-niak) (cf. also Fig. 178)... 

The temperature is electronically controlled and the fully automatic system of presetting heating periods and torque is electronic. The apparatus is equipped with a set of weights allowing a wide range of torques to be applied to specimens having different dimensions. The distance between the clamps can be varied in the range 20-100 mm. 

Recently, Hong and Zhou [48] worked out an automatic analytical technique based on the mercury(II) thiocyanate, iron(III) nitrate reagent. The fully automated apparatus uses the continuous-flow injection principle. A sample of 20 xL is injected into the water carrier stream, which merges with the reagent stream containing mercury(II) thiocyanate, iron(III) nitrate polyoxyethylene glycol dodecyl ether in aqueous methanol. After it passes through the reactor section, the absorbance is measured at 480 nm. 

To what extent an amino acid is boimd by exchange resins is, of course, a function of the d ree of ionization of the amino acid, i.e., of the dissociation constant K of the individual groups and the pH of the elutant. In other words, this method of fractionation utilizes the rather small differences of ionization of amino or carboxyl groups. Fully automatic but rather intricate apparatuses have been developed that carry out the chromatography and the measurement of ninhydrin color in the eluates, and plot the result as a curve. 

---