Average conversion rate

The ADI value for cyclamate of 0-11 mg/kg as allocated by JECFA17 is based on the no-effect level for cyclohexylamine, a 63% availability of cyclohexylamine for conversion due to absorption of 37% and an average conversion rate of 30%. The SCF has meanwhile reduced the ADI to 0-7 mg/kg assuming a higher conversion rate.18... 

Now, unless n = 1, (a ) j (a)", which means that the average conversion rate for all N drops is affected by the way in which the reactant A is distributed over these drops ... 

Synthroid is a man-made synthetically manufactured version of T-4/L-thyroxine. The average person produces about 76 MCG/d of T-4/L-thyroxine which is then converted by the liver into the more active T-3/L-triiodothyronine. This is true of the oral T-4/L-thyroxine medications as well. The average conversion rate of T-4 to T-3 is about 30-33%/ MCG. Since the conversion of T-4 to T-3 is dependent upon adequate levels of since and selenium, athletes commonly increase daily intake of these minerals during synthetic T-4/L-thyroxine use. 

Figure 4 shows the effect of initiator on the average conversion rate after a residence time of 60 minutes. At high soap and initiator levels, the number of particles, N, and rate of polymerization are high. Equation (4) indicates a 0.4 power dependency of number of particles to initiator concentration, and a least square fit of the data in Figure 4 gave this same dependency for rate of polymerization. 

The average conversion rate per m reactor of a gaseous reactant A absorbing in the liquid present in a well stirred slurry semi-batch reactor and then reacting according to an irreversible first order kinetics at the external surface of non porous catalyst particles, is given by [6l]. (Figure 7). 

The first quantitative model, which appeared in 1971, also accounted for possible charge-transfer complex formation (45). Deviation from the terminal model for bulk polymerization was shown to be due to antepenultimate effects (46). Mote recent work with numerical computation and C-nmr spectroscopy data on SAN sequence distributions indicates that the penultimate model is the most appropriate for bulk SAN copolymerization (47,48). A kinetic model for azeotropic SAN copolymerization in toluene has been developed that successfully predicts conversion, rate, and average molecular weight for conversions up to 50% (49). 

GL 16] [R 12] [P 15] On increasing the gas flow rate from 3.2 to 6.6 seem min at a constant liquid flow rate of 75 mg min, the conversion and average reaction rate increase [11] (see also [58]). This is a hint for mass transfer limitations. 

Results. Table 7.1 summarizes the results of the evaluation study obtained for CONCORD and CORINA. None of the programs crashed or produced any stereo errors. CORINA had a conversion rate close to 100%, whereas CONCORD converted only 91%. However, CONCORD was faster than CORINA with an average... 

Because of the dilution that results from the mixing of entering fluid elements with the reactor contents, the average reaction rate in a stirred tank reactor will usually be less than it would be in a tubular reactor of equal volume and temperature supplied with an identical feed stream. Consequently, in order to achieve the same production capacity and conversion level, a continuous flow stirred tank reactor or even a battery of several stirred tank reactors must be much larger than a tubular reactor. In many cases, however, the greater volume requirement is a relatively unimportant economic factor, particularly when one operates at ambient pres-... 

If one desires to utilize this reactor to carry out a first-order isomerization reaction of the type A - R, and if the rate constant for the reaction is 7.5 ksec-1, determine the average conversion that one expects in this reactor. Compare this value with those one would obtain in an ideal PFR and in an ideal CSTR having the same average residence time as our actual reactor. 

We win next develop expressions for X,(t) and the residence time Ts for complete reaction of the sohd in terms of parameters of systems for (hfiferent approximations of rate parameters. In a continuous reactor sohd particles are fed into reactor at a constant rate, and each transforms as a function of the time it has been in the reactor. Therefore, we would have to use the probabihty distribution function to compute the average conversion,... 

The step 1 product (0.009 mmol) and tetrabutylammonium tetrafluoroborate (0.598 mmol) were dissolved in 0.1 ml of acetonitrile and the solution added to a test tube containing 4-chloropyridine (0.50 mmol). After the mixture was heated for 30 minutes at 60°C the conversion rate reached 80%. The reaction mixture was then cooled to ambient temperature and concentrated. A yellow brown residue was isolated and was washed with diethyl ether and then dried under vacuum at ambient temperature and the product isolated having an average degree of polymerization of 52. 

In the following, the concepts of drop conversion rate and over-all conversion rate are used. In the same way as the chemical reaction rate is used to indicate the change in concentration of a reactant with time in a very small volume of a single phase in which the concentration may be considered to be uniform, the concept of drop conversion rate is used for the change in average concentration of a reactant with time where this average is taken over the whole volume of a single drop. Because of mass transfer limitation, this drop conversion rate may be lower than the pure chemical reaction rate (see Section II,B,1). 

In the same way, the over-all conversion rate is used to indicate the change with time of the concentration of a reactant averaged over the whole volume of one single phase present in the reactor. 

Further, the concepts of order of drop conversion and order of over-all conversion are introduced analogous to the well-known concept of order of chemical reaction. The order of drop conversion thus refers to the way in which the drop conversion rate responds to a change in average concentration of a reactant in that same drop. The order of (over-all) conversion refers to the way in which the over-all conversion rate responds to a change in average concentration of a reactant, where the average is taken over the whole corresponding phase present in the reactor (see further also Section II,A,3). 

Here a0 is the feed concentration of reactant A and k the drop conversion rate constant. If there is no segregation in the dispersed phase, which means that the rate of interaction is so high that all drops have the same concentration, then also the over-all conversion is a linear function of the average residence time r and given by/ = Tn(kb/tto) for r < ao/bk and / = 1 for Tn > a0/bk. If however there is no interaction at all, all drops will have different concentrations—depending on their age in the reactor—and the concentration distribution will correspond with the age distribution. 

When N a is the over-all conversion rate per unit volume which depends on the concentration of the reactants according to Na = kanbm, then the total order of conversion is n + m, where n and m are the partial orders of conversion in the reactants A and B, respectively. In a continuous stirred tank reactor the concentration b is constant and the same throughout the reactor, and since we are only interested in the effect on the partial conversion order n we put /cbm = ku so that N a = ha in which a is the average concentration of A in the whole reactor. 

When, however, the over-all conversion rate cannot be represented by a simple equation of the type NA = frid" the order of conversion is not clearly defined, and the application of the two formulas (7a) and (7b) will generally lead to different orders of conversion. For this reason it is always necessary to indicate in which way the average concentration d has been changed by changing the average residence time or by changing the feed... 

No segregation. In this case the average drop conversion rate has to be calculated by direct integration over the drop size distribution. After that, a mass balance gives the average concentration ... 

The latter measures the production rate per unit volume in kg/(m3 hr). For oscillatory and chaotic cases the average conversion Xs, the average yield Yp, and the average production rate Pp, as well as the average ethanol concentration Cp are also computed. They are defined as... 

Bulk Polymerization The conversion versus time plot for the bulk polymerizations of vinyl acetate and its deuterated analogues is shown in Figure 1. Vinyl tridueteroacetate has a conversion rate of 9.9 x 10 3/min which is identical with that of vinyl acetate (9.5 x 10 3/min) within the experimental error. However, trideuterovinyl acetate has a much higher conversion rate (1.69 x 10 2/min). The ratio of the rate of polymerization of tridueterovinyl acetate to the average of the other two monomers is 1.74 -. 03. 

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