Reaction Apparatuses

If one of the species is predominantly hydrated (e.g. the quinazoline cation then, by using the rapid-reaction apparatus and allowing... 

Hydroxy-8-azapurine was shown by rapid-reaction techniques (see Section II, E) to be anhydrous in the anion and hydrated in the neutral species. The hydration reaction has a half-time of about 0.5 second, which is too rapid for exact measurements with existing apparatus. The cation of 2-amino-8-azapurine was shown to have an anomalous value and ultraviolet spectrum, although its 6-methyl derivative is quite normal. Hydration in this case proved to be too fast to register in the rapid-reaction apparatus. 

Fig. 3. Diagram of mixing unit of rapid-reaction apparatus used in covalent-hydration studies.

The checkers employed a sealed ampoule of bromomethane of b.p 5° (obtained from Eastman Organic Chemicals) which was cooled to 0° and opened. After a boiling chip had been added to the ampoule, it was connected to the gas-inlet tube of the reaction apparatus with rubber tubing, and the ampoule was warmed in a water bath to distil the bromomethane into the reaction vessel. 

Ethylene was purchased from Matheson (>99.5%) and was purified by bubbling it sequentially through an aqueous solution of CuCl (2 g of CuCl in 200 mL of saturated aqueous NH4C1), concentrated H2S04, and then a KOH tube as shown in Figure 1. The reaction apparatus for the synthesis of the 1,3-diene is shown in Figure 2. 

The used raw materials were TiCU, oxygen, Ar and NaOH. The reaction apparatus consisted of gas purifiers, reactant preheaters, reactor, water cooler, separator and an off-gas treatment unit. The reactor was a 27 mm in ID. (32 mm in O.D.), 1430 mm in length quartz tube that was heated by a horizontal electrical furnace. A quartz rod and a ceramic rod, 6 mm... 

Figure 1. Fast-flow reaction apparatus. Ions or ion clusters are introduced into the flow tube from various sources and reactions proceed after they encounter the reactants added through a ring injector located at a selected position in the flow tube. The disappearance of the reactant ions and formation of products is monitored with the quadrupole mass spectrometer/electron multiplier shown. Taken with permission from ref. 19.

Vapor-phase analysis by means of a mass spectrometer built into a reaction apparatus has provided identification of transient species generated at high temperatures and low pressures. 

Remove the flask from the reaction apparatus and flush with nitrogen. 

The reaction apparatus (Figure 1) requires a tubular quartz flask with two side arms and a large ground-glass joint at the top to accommodate the water-cooled UV lamp. 

The reaction apparatus is a Schlenk tube ( 400-mL volume) with an N2 inlet (Fig. 1). A glass tube reaches into the reaction mixture. It is tightly fixed to the cap of the Schlenk tube the latter is linked to an escape valve filled with silicon oil. A solution of W(CO)5[C(NEt2)OEt]14a,b (4.54 g, 10 mmol) in... 

Estimations321 show that under the experimental conditions selected the concentration of the hydroxyl groups on the glass surface of the reaction apparatus is about 5 x 10 2 mol 1 1 related to the water content. Thus, the reaction of PhGE with amine... 

Caution. HBr(g) is vigorously evolved during the initial heating of the reaction mixture. Care should be taken to vent the reaction apparatus through... 

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