Reagent conversion

Azolium rings react readily with organometallic compounds. With a Grignard reagent, conversion (193) -> (194) is known in the benzothiazolium series, and 1,3-benzodithioly-liums give products of type (195). 

FIG. 14-12 Effects of reagent-concentration and reagent-conversion level upon the relative values Kca in the C02-Na0H-H 0 system. [Adapted from Eckeii et at, Ind. Eng. Chem., 59f2h 41 (1967).]... 

The batch reactor, above described, permits both to operate at quasi-zero conversion per pass and to evaluate the cat ytic activity at finite values of the reagents conversion. A typical test performed on Si02 catalyst at 600°C is presented in Figure 1. It is remarkable how in our approach the product selectivity is unaffected by the methane conversion. A special care was taken to avoid oxygen-limiting conditions and, hence, methane conversion data obtained for oxygen conversions below 20% only have been used for the calculation of reaction rates. 

Step 2a Reaction of an alkyl chloride with magnesium (Mg) provides the corresponding Grignard reagent (conversion of an electrophilic carbon to a nucleophilic carbon). 

Polymerization rate, yield, and intrinsic viscosity of the macromolecular products depend on monomer structure, initiator, reaction temperature, and solvent. The reaction rate and reagent conversion sharply increased in water in the presence of a redox system [FeS04-(NH4)2S208-K2S205]. Monomers 475 and 476 under these conditions polymerize virtually instantly with considerable heat liberation. Polymerization of iV-isopropenyltetrazoles 480-483 yielded polymers of relatively low molecular weight as compared to those obtained from 1-vinyltetrazoles 475-479 <2003RCR143>. 

Thermodynamic calculation results are shown in Table 4.1. For reaction (5), the main parameters are the following free energy variation 5165 kJ, equilibrium constant at 600 °C 3.4 10-3 and the reagent conversion to reaction products is negligibly low. Much less favorable is the equilibrium state in the reaction (6). Therefore, both reactions are not practically executed. Reaction (6) described in the monograph by Zeldovich el al. [39] and in the article by Anbar [40] runs at a temperature above 1273 K with nitric oxide formation by the mechanism, which includes elementary stages with atomic oxygen participation. However, atomic... 

The shifts of protons ortho, meta, or para to a substituent on an aromatic ring are correlated with electron densities and with the effects of electrophilic reagents (Appendix Chart D.l). For example, the ortho and para protons of phenol are shielded because of the higher electron density that also accounts for the predominance of ortho and para substitution by electrophilic reagents. Conversely, the ortho and para protons of nitrobenzene are deshielded, the ortho protons more so (see Figure 3.23). 

If system chosen by control analysis has acceptable reagent conversion then take as a candidate design for more detailed analysis... 

The worst-case conditions for reagent carryover must be identified, and the associated reagent conversion requirements 6 (permissible fractional carryover of reagent from the treatment system exit) computed. It should be noted that the worst-case load condition may be quite different from the worst-case disturbance condition for dynamic analysis. The worst-ease load characteristics will normally be bounded by the maximum neutralization load at the maximum flow and the maximum pH sensitivity and may be identified more precisely by worst-case design if desired. 

If steady-state reagent conversion of solid alkali is the limiting constraint, consider the following options ... 

Use a plug-flow reactor or a small CSTR as the first stage, using underneutralization to enhance overall reagent conversion. Feedforward control of reagent addition to the PFR, if practicable, avoids the poor feedback control characteristics of the PFR (see Section V.E). 

Shortcut analysis can be used to indicate whether a problem is likely. The time from 97 to 99% reagent conversion is about 1 minute based on the dynamic titration curves shown in Fig. 12 and the associated titration curve. Using this value of 1 minute as the equivalent reaction lag, t the carryover of reagent may be estimated by using Eq. (46). 

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