Macro apparatus

Other macro apparatus. Either a porcelain or a stainless steel spatula is very useful in the organic laboratory. A glass spatula may also be made by heating a piece of glass rod and pressing it to the desired shape. 

Fig. 46. Macro apparatus for bromination or any reaction where gases soluble in water are evolved...

Fig. 56. Macro apparatus for distillation under reduced pressure...

Macro apparatus conunonly used in elementary organic... 

Wet reactions macro apparatus and analytical operations on a macro scale... 

Although apparatus employing ground-glass joints is excellent for work on a macro scale, it is not always suitable for very small-scale work as the joints are often disproportionately large compared with the rest of the assembly. The semi-micro apparatus described on pp. 59-72 can therefore be considered as being of general utility for this scale of work, especially as the use of corks has been reduced to a minimum. 

Distillation under reduced pressure. The student should first read details of this operation on a macro-scale (p. 28). For micro-scale work the apparatus shown in Fig. 40 is very convenient. A small pear-... 

Conventional combustion calorimeters operate on a macro scale, that is, they require samples of 0.5-1.0 g per experiment. Unfortunately, many interesting compounds are available only in much smaller amounts. In the case of oxygen combustion calorimetry, however, several combustion microcalori-meters that only demand 2-50 mg samples have been developed in recent years. The achievements and trends in this area through 1999 have been reviewed [7-10], and interested readers are directed to these publications. Since then, a few new apparatus have been reported [11-17], Nevertheless, it should be pointed out that the general principles and techniques used to study compounds at the micro scale are not greatly different from those used in macro combustion calorimetry. 

Classical laboratory, manual methods conducted on a macro-scale where sample quantities arc in the range of grams and several milliliters. These are the techniques that developed from the earliest investigations of chemistry and which remain effective for teaching the fundamentals of analysis. However, these methods continue to be widely used in industry and research, particularly where there is alarge variety of analytical work to be performed. The equipment, essentially composed of analytical balances and laboratory glassware, tends to be of a universal nature and particularly where budgets for apparatus are limited, the relative modest cost of such equipment is attractive. 

One of the first breaks from traditional analytical chemistry was the addition of microchemical methods. These methods essentially extended macro-scale techniques so that lliey could be applied for determinations involving very small (milligram) quantities of samples. These methods required fully new approaches or extensive modifications of macroscale equipment. Consequently, the apparatus usually was sophisticated, relatively costly, and required, greater manipulative skills. Nevertheless, microchemical methods opened lip entirely new areas of research, making possible the determination of composition where the availability of samples, as in many areas of biochemistry, was confined to very small quantities. 

The Carius method can be worked on a micro (see Pregl, loc. tit.) or hemi-macro scale. Halogens can be estimated by other methods (see, inter alia, Bobranski and Sucharda, loc. tit.) in which the substance is completely oxidised in the dry state, Cl and Br being trapped in solid BaC03,1 in Na2S03 in a special apparatus. 

For quick reference, Tables 6.1 through 6.3 provide a summary of the key features, capabilities, limitations, and advantages of different experimental apparatuses for macro- (Table 6.1), meso- (Table 6.2), and molecular-level (Table 6.3) measurements of hydrate thermodynamic and kinetic properties. 

Equilibrium dialysis apparatus, e.g. variable speed dialyser Dianorm-4 (Dianorm Munich Germany). The dialyser is equipped with 1 mL macro cells (4.5 cm2 working surface area) and cellulose dialysis membrane (63 mm diameter, molecular cut off weight 10 KDa) The apparatus is placed in a water bath with a circulating system to obtain a constant temperature of 37 °C in the system. 

The selective extraction of a radioactive nuclide as a nonpolar compound or complex from an aqueous solution by an immiscible organic solvent Is frequently the most satisfactory method for making a fast radiochemical separation In either macro or trace concentrations. Separations by solvent extraction are simple, convenient, clean, and rapid. They usually require apparatus as uncomplicated as a separatory funnel and may readily be adapted to remote handling procedures. 

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