Bourne reactions

Let s now briefly look at one of the most important experimental fast competitive reactions. Let s select the Third Bourne Reaction (Bourne and Yu, 1994 Yu, 1993), which is the hydrolysis of ethylchloroacetate (ECA) reacting with NaOH in competition... 

Figure 10.46. Yield data (Xq = Fraction EGA converted to NaCA) for the 3 Bourne Reaction as tested in 2, 20, 180 and 600 liter reactors correlated at Xq vs blend time (6BD impeller used with feedpipe discharging downward to the eye of the impeller).

Figure 10.47. Yield data vs initial molar feed ratio for 3 Bourne Reaction occurring in a 1/4 inch (0.64 cm) Kenics Helical Element Mixer used on a recycle loop on 20 liter semi-batch reactor agitated with a 6BD impeller.

Use an initial recycle ratio (i.e., the ratio of the initial molar feed rate of the semi-batch chemical species [e.g., NaOH for the third Bourne Reaction] to the molar feed rate of the fastest reacting chemical species in the recycle loop [i.e., HCl for the third Bourne Reaction]) of at least 3 1. 

Pipeline Mixers used as Reactors for Fast C/C Reactions. Taylor (1996) and colleagues (1998) conducted a study to determine scale-up procedures for fast C/C reactions in pipeline mixers. They used the fourth Bourne reaction, which is the acid catalyzed hydrolysis of dimethoxypropane (DMP) to acetone and methanol. This is an extremely rapid reaction when catalyzed by HCl. The competitive reaction scheme, which is a unique one, is one in which NaOH reacts practically instantaneously with the HCl to remove the catalyst for the hydrolysis reaction. A water/ethanol solution of NaOH and DMP was fed as a main stream to a Kenics helical element mixer and an aqueous side stream containing slightly greater (abour 5% greater) than equimolar amount of NaOH was fed as the side stream. The product was analyzed by GC for methanol and acetone. For extremely rapid mixing, essentially no hydrolysis occurred however, for slow mixing, essentially all the DMP is hydrolyzed because acidic conditions cause very rapid hydrolysis of the DMP. 

Third Bourne reaction competitive reaction of NaOH with HCl and EGA. 

Scale-up of a Static Mixer Reactor for the Fourth Bourne Reaction... 

Laboratory studies of mixing-sensitive homogenous reactions have been done by many investigators using the four reactions that are known as the Bourne Reactions. These studies and others fleshed out the previous theoretical predictions and established... 

There are mixing-time sensitive reactions where fi/2 tmix will cause a difference in selectivity. A widely studied example is the Bourne reaction... 

Computational fluid mechanics has had some notable successes in duplicating experimental results for turbulent reactors, both tubes and tanks. As one example, one simulation closely agreed with experiments for the yield of a Bourne reaction in a fed-batch laboratory reactor that was stirred by a half-moon agitator ... 

Figure 8.10 Schematic of limiting cases with Bourne reactions.

Bourne Azo-Coupling Reactions. The second Bourne reaction scheme (see Table 13-4) is the most commonly used reactive mixing characterization tool. It is... 

Tipnis et al. (1994) investigated experimentally the scale-up of a competitive-parallel chemical reaction (the third Bourne reaction see Section 13-2.5) in stirred vessels of 2.15, 20, 178, and 600 L. The vessels were geometrically similar, with two feed positions in each. The impellers were all six-blade disk turbines with D/T =. The feed points were at two distances (G/T of 0.33 and 1.33) above the impellers near the impeller shaft. The chemical reaction rates at 298 K were as follows ... 

Middleton et al. (1986) measured yields of a competitive-consecutive chemical reaction under various stirred vessel conditions (size, impeller rotation rate) for semibatch reactors in which the added reactant was injected rapidly. They used the Bourne reaction, which is the reaction of 1-naphthol (component A) with diazotized sulfanilic acid (component B) to produce two products according to... 

Bourne (1983) realized the important effect of the mixing process on the yield and product distribution of series-parallel chemical reactions. He and co-workers used the first Bourne reaction, described in Section 13-2.5, to do experimental studies of the effects of mixing on yield. They made extensive use of this reaction system (Bourne et al., 1981 Bourne and Rohani, 1983 Angst et al., 1984 Bourne and Dell Ava, 1987) and used the results to determine parameters in their models. 

Figure 13-34 Yields in four stirred vessel sizes. The 19 and 65 L tanks were studied by Baldyga and Bourne (1992) feed points were at the impeller tip and midway between the tip and the tank wall. In the 100 and 1000 gal (378 and 3780 L, respectively) tanks studied by Paul (1988), the feed points were all at the impeller blade tips. In both cases a Bourne reaction of the form A + B R R + B S was used.

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