Inner phase reactions types

Figure 9.5 Different types of inner phase reactions...

Other types of non-micro-channel, non-micro-flow micro reactors were used for catalyst development and testing [51, 52]. A computer-based micro-reactor system was described for investigating heterogeneously catalyzed gas-phase reactions [52]. The micro reactor is a Pyrex glass tube of 8 mm inner diameter and can be operated up to 500 °C and 1 bar. The reactor inner volume is 5-10 ml, the loop cycle is 0.9 ml, and the pump volume adds a further 9 ml. The reactor was used for isomerization of neopentane and n-pentane and the hydrogenolysis of isobutane, n-butane, propane, ethane, and methane at Pt with a catalyst. 

Related to the experimental studies performed in our laboratory, in this review packed-bed membrane reactors were discussed. It should be mentioned that there are significant investigational activities devoted to study catalytically active membranes where the catalyst is deposited in either the membrane pores or on the inner or outer surface of the tubes [11]. Another similarly interesting and promising principle is based on using the Contactor type of membrane reactors, where the reactants are fed from different sides and react within the membrane [79]. Significant efforts have been made to exploit this principle for heterogeneously catalyzed gas-liquid reactions (three-phase membrane reactors) [80, 81]. 

Equation 4.3 is formally similar to a complexation reaction between SR(s) and the aqueous solution species on the left side. Indeed, the solid-phase product on the right side can be interpreted on the molecular level as either an outer-sphere or an inner-sphere surface complex. The latter type of adsorbed species was invoked in connection with the generic adsorption-desorption reactions in Eqs. 3.46 and 3.61, which were applied to interpret mineral dissolution processes. In general, adsorbed species can be either diffuse-layer ions or surface complexes,7 and both species are likely to be included in macroscopic composition measurements based on Eq. 4.2. Equation 4.3, being an overall reaction, does not imply any particular adsorbed species product, aside from its stoichiometry and the electroneutrality condition in Eq. 4.4. 

The mechanisms and rates of metal-catalyzed initiation operative in individual reaction systems are determined by a complex mixture of factors the metal and type of complexes it forms (inner sphere or outer sphere), the chelator or complex-ing agent, redox potential of the metal and its complexes, solvents, phase localization of the metal, and availability of oxygen or preformed hydroperoxides. The reactions outlined below show the multiplicity of mechanisms possible. 

There are two column types, which differ in their performance packed columns and capillary columns (Figure 2.7). For packed columns the stationary phase is deposited or bonded by chemical reaction onto a porous support. For capillary columns a thin layer of stationary phase is deposited onto, or bound to the inner surface of the column. 

Okahata, Y., and K. Ariga, A New Type of Phase-Transfer Catalysts (PTC) Reaction of Substrates in the Inner Organic Phase with the Outer Aqueous Anions Catalyzed by PTC Grafted on the Capsule Membrane, J. Org. Chem., 51, 5064 (1986). 

Small tubes are commonly employed where the reaction is rapid and/or the heat of reaction must be removed rapidly. The two conventional types of tubular reactors are (1) coils immersed in a constant-temperature bath and (2) a jacketed pipeline in which the inner tube is designed to withstand the reaction pressure. A modification of the conventional jacketed-pipe reactor can be used where it is desirable to minimize the thickness of the inner tube in order to reduce the area required for heat transfer. An example of this type of equipment is the liquid-phase heat exchanger of the Bureau of Mines, in which the outside pipe has an outside diameter of 4 2 ill- wall thickness of 1.005 in. The outside diameter of the inner tube is in., but the wall thickness is only 0.16 in. The worldng... 

---