Assembling Apparatus

The first known distillation apparatus, assembled in the first century ce, is attributed to Mary the Jewess, an alchemist who lived in the Middle East. 

When an annealing oven is not available, even quite large pieces of equipment can be annealed by flame. Apparatus assembled on the bench can often only be annealed by a flame. As a general principle each joint should be annealed as it is completed, unless a further join is to be made, or another operation is to be performed immediately in the same region or so near to it that the whole of the first joint can be kept hot—then the whole is annealed together. 

Figure 1. Permanent Apparatus Assembly for Quantitative DDT Estimations...

D. 4a(S),8a(R)-2-Benzoyloctahydro-6(2H)-isoquinolinone (4). Palladium (Pd), 10% on carbon, 4.0 g, (Note 21) is placed in a 500-mL Parr bottle under N2 and carefully wetted with 50 mL of cold denatured ethanol (EtOH). A slurry of 34.7 g of enone 3 (0.14 mol) in denatured EtOH (250 mL) is added and the Parr shaker apparatus assembled. After the system is purged with nitrogen-hydrogen (N2/H2), the reaction is shaken at 50 psi H2 and 50°C until H2 uptake is complete (1 hr, Note 22). The catalyst is filtered over a Celite pad (Note 23) and rinsed with warm chloroform (CHCI3) (4 x 75 mL). The filtrate is concentrated under reduced pressure, dissolved in 90 mL of CH2CI2 and crystallized with 200 mL of hexanes. The crystalline solid is filtered, rinsed with hexanes and dried to afford 34.3 g (98%, Note 24) of the ketone 4, representing a 51% yield over four steps. 

When performing laboratory work in inorganic synthesis, one has to assemble the required apparatus or setup from individual components, generally made of glass. The success of an experiment and also its safety often depend on the quality of apparatus assembly. This is especially important in the synthesis of readily hydrolyzing substances, and also in work performed in an atmosphere of hydrogen, carbon monoxide, or chlorine. 

The main requirements which apparatuses assembled by students must meet is their good tightness, compactness, and an attractive appearance. 

A calcium chloride guard-tube is illustrated in Fig. 2.28 which is widely used for protecting apparatus assemblies from the ingress of moisture. 

This nitrogen inlet may also be used with other apparatus assemblies where an inert atmosphere is to be preserved in the reaction vessel, for example as illustrated in Fig. 2.58. Bubblers are also commercially available. 

Remove the flask B (500 ml capacity) from the apparatus assembly and add 100 ml of absolute ethanol, 5.0 ml of 0.2 m ethanolic chloroplatinic acid and 5g of decolourising charcoal insert a 38 mm Teflon-covered follower bar. 

Commercially available ozonisers (e.g. from UVP International) use either air or oxygen and are capable of yielding about 0.005 mol 03/hour (with air) or 0.5 mol 03/hour (with oxygen). A commercial ozoniser may be incorporated, by means of PVC tubing, in place of the Berthelot tube on an apparatus assembly similar to that above. 

The vast majority of photochemical syntheses have been conducted in the liquid phase, hence the apparatus assembly for a photochemical reaction must take into account the light transmission characteristics of the material from which the reaction vessels are made. Pyrex glass transmits most of the incident light above about 300 nm and may be used in the construction of apparatus for reactions which require light above this wavelength. Quartz vessels, transparent down to 200 nm, must be used for reactions which require light below 300 nm. Certain types of quartz allow transmission below 200 nm. 

When reasonable amounts of liquid components are available (> 5 ml) the boiling point is readily determined by slowly distilling the material from a pear-shaped flask in an apparatus assembly shown in Fig. 2.98, and recording the temperature at which the bulk of the compound distils. Due attention should be paid to the experimental procedure which was discussed in detail in Section 2.24. 

For smaller quantities of liquid compounds (0.5-3.0ml) the material should be distilled in the apparatus assembly shown in Fig. 2.99. 

An alternative technique (which uses essentially the same apparatus assembly as described above) involves passage of borane directly into a solution of the organic substrate in tetrahydrofuran, diglyme or ether to effect immediate... 

This gas may be conveniently prepared by allowing a solution of two parts of iodine in one part of hydriodic acid (d 1.7) to drop on to excess of red phosphorus the apparatus assembly employed could be of the general type illustrated in Fig. 4.3. The evolution of hydrogen iodide takes place in the cold when the evolution of gas slackens considerably, the mixture should be gently warmed. 

Miao et al. (2003) have been able to reconstitute the essential features of retraction in vitro by adding Yersinia phosphatase (YOP) to the MSP-based motility apparatus assembled from cell-free extracts from Ascaris sperm... 

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