Method syringe-reactor

The second (syringe-reactor) method permits the study of the kinetics of the activation in the absence of the gas phase. Though the solubility of alkanes in water or sulfuric acid is very low it is sufficient to follow the decreasing concentration of RH in the solution by GLC tool. The competitive versions of the method (when two substrates, RaH and RbH, are used in the same experiment), based on the equation... 

The stopped-flow method uses syringe-type pumps, (a), to feed the components, A and B, through a mixing cell, (c), into the reaction cell, (d), which can be an optical cell (Fig. 3.3-5). The pumps, mixing cell, and reactor are well thermostatted. The flow is stopped when the syringe, (e), is loaded and operates a switch, (f), to start the monitoring device. The change in concentration is detected either by spectroscopy or conductivity measurement. 

Whereas much mechanistic information can be obtained by one of the above methods, any practical applications must be demonstrated under conditions similar to process operation, i.e., continuous flow. Small glass reactors which allow controlled addition of reagents by syringe pump and continuous removal and monitoring (IR spectroscopy) of product mixture have been developed. Much of the information obtained from semibatch operation has been reproduced under these continuous flow conditions. 

This aspect of batch reaction methods is also critical to obtaining good results. Rapid filtration is normally used to separate the solid and liquid phases when samples are removed from a typical batch reactor. When rapid reactions are studied, sampling with the syringe sampler must be rapid and reproducible as the reaction is continuing as thc sample is taken. A 5-s sampling time is nearly optimal, but il should not exceed 10 s including connec-... 

Fig. 1.21. Vial reactor used in the CFD method. 1 = Container for liquid 2 = stopper 3 packing 4 = tap 5 = syringe. A, open vial reactor B, closed vial reactor. From ref. 6.

Reaction GC is a variation of GC in which chemical reaction is coupled with the chromatographic separation. Chemical transformations in analytical reaction gas chromatography always take place in an integral chromatographic system, in a reaction syringe, a precolumn reactor, or the column itself. The combination of the chemical and the chromatographic methods is a more efficient tool for... 

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