Sensitivity Towards Temperature Reaction Number

Since the sensitivity of the reaction rate towards temperature, and therefore of the heat release rate of a reaction, dominates the heat balance, it is important to define 

the relative variation of the reaction rate with temperature is 

2 is called the temperature sensitivity. By multiplying this with the 

In this section we consider different criteria developed on the basis of a heat balance. The criteria described here represent a selection of easy to use, but also more advanced, criteria allowing discrimination between dynamically stable situations and situations where runaway is likely to occur. Their use will be described in Chapters 6 to 8. 

In Section 2.5.2, the Semenov diagram was used to show the critical cooling medium temperature. In the same way it allows discrimination of a stable operation conditions from a runaway situation. A stable operation is achieved for a limit value of the Semenov criterion / (also called Semenov number)  

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Alkyl/alkoxide metathesis employing OfBu as alkoxide component revealed to be even more complicated and unpredictable [222-224]. The reactivity of well-characterized (CpR)3 Ln(OtBu)/ species towards alkali metal alkyls seems to be quite sensitive to specific reaction conditions, including choice of solvent, number and type of cyclopentadienyl co-ligands or reaction temperature. 

Produced annually in ton quantities (2). They are industrial objectives for which the riedel-Crafts strategy has frequently been used. From the point of view of pollution prevention, there are a number of reasons why alternatives must be considered. The Friedel-Cr ts pathway involves corrosive and air sensitive acid chlorides, Lewis acids such as duminum chloride, stannic chloride or titanium tetrachloride and solvents such as nitrobenzene, carbon disulfide, carbon tetrachloride or methylene chloride (3). Althou some research directed toward minimizing the amount of Lewis acid needed for the Friedel-Crafts reaction has been reported, this modification requires elevated temperatures (4). Friedel-Crafts reactions conducted with acidic resins nave also been reported. This research appears promising but is in the early stages (5). Obviously, an attractive alternative to the traditional Friedel-Crafts reaction would have an impact on pollution prevention. 

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