Reaction number

Next, a series of runs was conducted to determine the effect of various alkali metal hydroxide additions along with the sponge nickel catalyst. The 50 wt. % sodium hydroxide and 50 wt. % potassium hydroxide caustic solution used in the initial test was replaced with an aqueous solution of the alkali metal hydroxide at the level indicated in Table 2. After the reaction number of cycles indicated in Table 2, a sample was removed for analysis. The conditions and results are shown in Table 2. The results reported in Table 2 show the level of 2° Amine in the product from the final cycle. The level of NPA in all of the mns was comparable to the level observed in the initial test. No significant levels of other impurities were detected. 

Reaction Reaction number Rate constant Variation in odd oxygen... 

Fig. 4. Impact of process intensification on a hypothetical homogeneously catalyzed liquid reaction. Number of parallel operating reactors depending on the reaction temperature...

We do this for isothermal constant-density conditions first in a BR or PFR, and then in a CSTR. The reaction conditions are normalized by means of a dimensionless reaction number MAn defined by... 

Determine the fractional conversion /A of A for a zero-order reaction (A - products) in a laminar flow reactor, where c o = 0.25 mol L 1, jfcA = 0.0015 mol L-1 s-1, and t = 150 s. Compare the result with the fractional conversion for a PFR and for a CSTR 16-4 Using equation 16.2-18, develop a graph which shows the fractional conversion /A as a function of the dimensionless reaction number MAo for a zero-order reaction, where Mao = kt/cAo< equation 4.3-4. what are the real limits on Mao ( e > values f°r which reasonable values of /A are obtained) Explain. 

In Table 17.2, fA (for the reaction A products) is compared for each of the three flow reactor models PFR, LFR, and CSTR. The reaction is assumed to take place at constant density and temperature. Four values of reaction order are given in the first column n = 0,1/2,1, and 2 ( normal kinetics). For each value of n, there are six values of the dimensionless reaction number MAn = 0, 0.5, 1, 2, 4, and °°, where MAn = equation 4.3-4. The fractional conversion fA is a function only of MAn, and values are given for three models in the last three columns. The values for a PFR are also valid for a BR for the conditions stated, with reaction time t = t and no down-time (a = 0), as described in Section 17.1.2. 

The dimensionless second-order reaction number, from equation 4.34, with T = t (constant density), is... 

For a relatively small amount of dispersion, what value of Pei would result in a 10% increase in volume (V) relative to that of a PFR (Vpf) for the same conversion (/a) and throughput (q) Assume the reaction, A - products, is first-order, and isothermal, steady-state, constant-density operation and the reaction number, Mai = at, is 2.5. For this purpose, first show, using equation 20.2-10, for the axial-dispersion model with relatively large Per, that the % increase s 100(V - V pfWpf = 100MAi/Pei. 

All the other reactants will be ignored here to make the analysis more straightforward, even if steps (1) and (2) are, in fact, bimolecular. We again write the reaction number within brackets to avoid confusion we do not want to mistake the subscripted number for the order of reaction. We call the rate constant of the first reaction k([) and the rate constant of the second will be k(2). 

Reactions and rate coefficients are numbered consecutively throughout each main section, the reaction number appearing as a subscript in the symbol for the corresponding rate coefficient. For a reaction... 

Figure 16.2 Thermochemical cycles involving the heterolytic and homolytic cleavages of the R-X bond, and reduction or oxidation processes. The reaction numbers are the same as in figure 16.1.

Grewer, T., DECHEMA Monograph, 1980, 88(1818-1835), 21-30 One of the principal causes of batch chemical processes becoming unstable is the combination of a high reaction exotherm and a low reaction rate (or rates if there is more than one component reaction in the overall process). A secondary cause of reaction delay leading to instability is too little mass transfer. To permit safe operation of such reaction systems, the reaction energy (which may be expressed as a dimensionless reaction number) and the reaction rate(s) must be known. The possibility of there being a lower safe limit as well an upper safe limit to reaction temperature is discussed. 

We observed that in the absence of ultrasound (C), but the presence of initiator (reaction number 1 and 2), the rate (or yield (Y) per unit time) and molar mass data (M ) conformed approximately, as expected, to that for conventional polymerisation - i. e. quadrupling the initiator concentration led a doubling of the yield (Eq. 5.4) and a halving of the molar mass (Eq. 5.5). 

Reaction number Type Reaction temperature [°q [AZBN] [10 mol dm ] Reaction time [min] Reaction volume [cm Yield [%] no ] [10 ] HI... 

Scheme 2.1 Relationships between RsSiH and its related radicals, ions, and radical ions (The numbers refer to reaction numbers as they appear in the text)...

Reaction Number of ATP or reduced coenzyme directly formed Number of ATP ultimately formed... 

As is normally the case with esterification reactions, an equilibrium situation exists in this particular series, and Reaction 2, with respect to its degree of completion is dependent upon the concentration of the olefin in the reaction medium. We studied the effect of the olefin excess in the reaction on yield of ester and found that at levels less than 50%, the yields based on the acid-ester components were considerably less. With olefin excesses larger than 50%, the rate of the primary reaction, that is formation of the diester, was decreased. We therefore determined that an olefin excess of about 50% favored the primary reaction (number 2) as opposed to the secondary reaction in which the olefin can undergo polymerization in the acid media. 

The remaining series of reactions of fatty acid synthesis in eukary-l otes is catalyzed by the multifunctional, dimeric enzyme, fatty acid synthase. Each fatty acid synthase monomer is a multicatalytic polypeptide with seven different enzymic activities plus a domain that covalently binds a molecule of 4 -phosphopantetheine. [Note 4-Phosphopantetheine, a derivative of the vitamin pantothenic add (see p. 379), carries acetyl and acyl units on its terminal thiol (-SH)j group during fatty acid synthesis. It also is a component of 00-enzyme A.] In prokaryotes, fatty acid synthase is a multienzyme complex, and the 4 -phosphopantetheine domain is a separate protein, referred to as the acyl carrier protein (ACP). ACP is used below to refer to the phosphopantetheine-binding domain of the eukaryotic fatty acid synthase molecule. The reaction numbers in1 brackets below refer to Figure 16.9. [Note The enzyme activities listed are actually separate catalytic domains present in each mulf-1 catalytic fatty acid synthase monomer.]... 

Type nf reaction Number of known reactions Examples nf reactions... 

---