Three-phase noncatalytic reactions

we consider reaction between solid [B] suspended in a liquid and gas A bubbled through it. If solid B is slightly soluble in the liquid, reaction occurs between dissolved A and B in the liquid phase. If B is insoluble, dissolved A diffuses and reacts with B within the solid. The situation represented by the first case is similar to gas-liquid reactions but with provision for solid dissolution. The second case is similar to that considered in Chapter 15 for reaction between an insoluble solid and a liquid. 

This is an interesting situation in organic technology and synthesis. Examples are the dissolution of acetylene in an aqueous slurry of CuCl as a step in the manufacture of propylene oxide and the alkylation of naphthalene with ethylene in a liquid medium in the presence of BF3-phosphoric acid as a dissolved catalyst. Note that the presence of the dissolved catalyst does not in any way alter the physical features of the system. 

Hydrogenation of furfurol and its derivatives Cu-Cr oxide Important intermediates Heidegger et al. (1971) 

Amination of monoethanolamine Undisclosed Ethylenediamine, versatile chemical Kohn (1978) 

Hydrogenation of glucose Raney Ni Sorbitol, intermediate in pharmaceuticals Brahme and Doraiswamy (1976) 

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The thrust of this chapter is on reactions and reactors involving a gas phase, a liquid phase, and a solid phase which can be either a catalyst (but not a phase-transfer catalyst) or a reactant, with greater emphasis on the former. The book by Ramachandran and Chaudhari (1983) on three-phase catalytic reactions is particularly valuable. Other books and reviews include those of Shah (1979), Chaudhari and Ramachandran (1980), Villermaux (1981), Shah et al. (1982), Hofmann (1983), Crine and L Homme (1983), Doraiswamy and Sharma (1984), Tarmy et al. (1984), Shah and Deck wer (1985), Chaudhari and Shah (1986), Kohler (1986), Chaudhari et al. (1986), Hanika and Stanek (1986), Joshi et al. (1988), Concordia (1990), Mills et al. (1992), Beenackers and Van Swaaij (1993), and Mills and Chaudhari (1997). Doraiswamy and Sharma (1984) also present a discussion of gas-liquid-solid noncatalytic reactions in which the solid is a reactant. 

The calcium bisulfite acid used in the manufacture of sulfite cellulose is the product of reaction between gaseous sulfur dioxide, liquid water, and limestone. The reaction is normally carried out in trickle-bed reactors by the so-called Jenssen tower operation (E3). The use of gas-liquid fluidized beds has been suggested for this purpose (V7). The process is an example of a noncatalytic process involving three phases. 

Film diffusion resistance All bubbling reactors such as Catalytic fixed-bed G/S reactors BFB and three-phase reactors All fast, noncatalytic G/S reactions such as combustion and gasification ... 

Mechanically agitated slurry reactors are widely used in three-phase catalytic and noncatalytic reactions. In aerated slurry reactors, the three regimes outlined in Table V prevail. These regimes are schematically illustrated in Fig. 11. The gas flow rate and stirrer speed where the transition from regimes a to b or b to c with a Rushton turbine stirrer occurs can be estimated from the relationships described in Table VI. 

Engineering of organic synthesis analysis and design of reactors for the important classes of reactions, mainly homogeneous, two-phase catalytic, two-phase noncatalytic, and three-phase catalytic and noncatalytic... 

In this chapter, we consider multiphase (noncatalytic) systems in which substances in different phases react. This is a vast field, since the systems may involve two or three (or more) phases gas, liquid, and solid. We restrict our attention here to the case of two-phase systems to illustrate how the various types of possible rate processes (reaction, diffusion, and mass and heat transfer) are taken into account in a reaction model, although for the most part we treat isothermal situations. 

The process in question involved the reaction of two materials, A and B, to produce a product C. The reaction was noncatalytic, homogeneous, and in the gas phase. It took place in a tubular reactor which could not be considered either adiabatic or isothermal. The reactor was divided into four sections, the first three of which were cooled while the fourth was adiabatic. Coking of the reactor tube introduced a time variant in the system, requiring adjustment of operating conditions and eventual shutdown for cleaning. 

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