Fouling processes addition reactions

In a program to combat fouling from chemical reactions, it is usual to employ a blend of chemicals to offer wide-ranging protection. Many of the additives available are proprietary and it will be necessary to seek the advice of the suppliers before applying to the process stream. 

During normal operation, it is essential to ensure sufficient cooling in order to control the temperature of the reactor, hence to control the reaction course. This typical question should be addressed during process development. To ensure the thermal control of the reaction, the power of the cooling system must be sufficient to remove the heat released in the reactor. Special attention must be devoted to possible changes in the viscosity of the reaction mass as for polymerizations, and to possible fouling at the reactor wall (see Chapter 9). An additional condition, which must be fulfilled, is that the reactor is operated in the dynamic stability region, as described in Chapter 5. 

The simultaneous application of ultrasonic irradiation to an electrochemical reaction which has been termed sonoelectrochemistry has been shown to produce a variety of benefits in almost any electrochemical process. These include enhanced chemical yield in electrosynthesis and the control of product distribution improved electrochemical efficiency in terms of power consumption, improved mixing, and diffusion in the cell minimization of electrode fouling accelerated degassing and often a reduction in the amount of process-enhancing additives required. In a major chapter devoted to this topic, Suki Phull and Dave Walton have attempted to cover the majority of applications of ultrasound in electrochemistry including electrochemical synthesis, electroanalytical chemistry, battery technology, electrocrystallization, electroinitiated polymerization, and electroplating. 

Finely divided particles of MAO are precipitated from a toluene solution by addition of /3-decane followed by evaporation. Suspension of these particles in decane followed by reaction with toluene solutions of Cp 2ZrCl2 (Cp 2 = Cp2 or Et(Ind)2 ) affords a solid catalyst which can be used in solution or gas-phase polymerization processes using ethylene or propylene as the monomers. Solids also separate from a toluene solution of MAO on addition of an equal volume of hexane or isobutane.Insoluble gels in toluene solutions of MAO, ordinarily a nuisance, can be filtered off, resuspended in aliphatic hydrocarbons, and reacted with metallocene dichlorides to produce active catalysts for olefin polymerization without reactor fouling. 

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