Conversion Yield Calculations

The mass fraction of a sugar in the slurry (g/g) may be calculated from its liquid-phase concentration C (g/L) using the relationship 

To determine the extent of conversion of an enzymatic hydrolysis reaction using this approach, measured liquid concentration values are first used with Equations 4.3 and 4.4 to obtain values for the mass fractions of liquid and soluble sugars in the slurry. These values are then used with Equation 4.1 to calculate the conversion yield. 

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The percent yield calculated in this way corresponds to the amount of product X relative to all products and is not the same as the percent of the starting material converted to X (this latter expression is given by x/a/Co, where C0 is the number of moles of reactant). It should be noted that similar to the relationship between rate and efficiency, a low quantum yield for a photochemical reaction does not necessarily mean that it will be formed in a low yield (the converse is true, however). If, for example, x = 0.005 and 2, t = 0.00005, then... 

The aldol condensation reaction of acetone was performed over CsOH/Si02 at a range of reaction temperatures between 373 and 673 K (a typical product distribution is shown in Figure 2). Table 1 displays the conversion of acetone along with the selectivities for the products produced once steady state conditions were achieved. Figure 3 presents the effect of temperature on the yield of the products. The activation energy for acetone conversion was calculated to be 24 kJ. mol 1. 

In the runs carried out by the checkers, conversion of reactant was slightly lower than 50% as shown by the recovery of 2-toluic acid in 63-74% yield. In these runs benzocyclobutenone was obtained in 17-20% yield only. However, the yield calculated with respect to reactant consumed and not recovered as 2-toluic acid amounted to 56-64% and thus did not differ significanlty from the value given in the procedure. 

Mass balance, yields, and conversion were calculated. The yield to conversion functions were determined using linear regression. Tests with mass balances between 95 and 99 wt% were accepted. 

Balanced equations, diverse conversion factors, limiting re ents, and percent yield calculations all now tremble before you. Probably. Be sure your powers over them cire as breathtaking as they should be by checking your answers. 

Table III is an analogue of Table II for typical organic unit processes. Yields and conversions were calculated as in Sec. IIIC2.

It is important to monitor the time that the proanthocyanidin is allowed to react with the phloroglucinol solution. The products formed are not stable under acidic conditions, and it is therefore critically important that the reaction not exceed 20 min. Of particular concern are the flavan-3-ol monomers, which degrade more rapidly than the phloroglucinol adducts (Kennedy and Jones, 2001). Excessive degradation of the flavan-3-ol monomers will result in reduced amount of terminal subunits. This in turn will reduce the conversion yield and increase the average degree of polymerization calculated. 

For the alkali-catalyzed transesterification reaction of rapeseed oil, we investigated several operating conditions reaction temperature, type and amount of catalyst, molar ratio of methanol to oil, and reaction time. In alkali-catalyzed transesterification, the amount of free fatty acid was assumed to be below 0.5% on the basis of oil weight, in order to obtain high conversion yield (13). The conversion yield or percentage of conversion was calculated by dividing the amount of product by the maximum theoretical product. Because it has a high acid value, the activity of catalyst was diminished in the transesterification reaction. As reported in Table 1, the fatty acid content of rapeseed oil used for this experiment was 0.018%, which was lower than the proposed value (below 0.5%). 

Phenyladamantyl ketone, when irradiated to 90 % conversion, yields an enrichment in the 13C content in both the products and recovered starting material. The recovered starting material is 200% enriched in 13C content benzaldehyde is 160% enriched, and adamantane in 180 % enriched (calculated assuming selective enrichment at the benzaldehyde CO carbon and the 1-carbon of adamantane)23). The role of the micelles in this reaction provides reduced dimentionality allowing recombination of the radical pairs to occur over diffusional processes. By comparison, viscosity has only a slight effect on the isotope enrichment (Table 5). 

Pressure kPa. A/B means A, butene partial pressure B, total pressure. Conversion is calculated by assuming that all n-butenes are reactants even if (he true reactant is one particular n-butene. Yield, inversion X selectivity. n.m., not mentioned. 

The solution of the system equations for all unknown variables is straightforward. The idea gas equation of state applied to the fresh feed stream yields no- The specified overall CO conversion yields h from the equation 0.01 3 = (1 - 0.98)no Raoult s law at the condenser outlet combined with the calculated value of h yields /i6, and an overall carbon balance yields Balances on CO and CH3OH at the mixing point yield hi and hi, and an energy balance for the same subsystem yields Ta. An energy balance on the preheater then yields Qh> A methanol balance on the condenser yields hi, and then energy balances on the reactor and the condenser yield and Q, respectively. 

The simple form of Eq. (2-91) shows that selectivity and yield calculations can advantageously be carried out by dividing the rate for one reaction by that for another, eliminating time in the process. Since yield and selectivity are usually more important than total conversion for complex-reaction systems, this procedure will be emphasized in the following section. The possible combinations of simultaneous, parallel, and consecutive reactiom are very large. A few irreversible first-order cases will be analyzed in Sec 2-10 to illustrate the method of approach. Then in Sec. 2-11 a different type of complex system, chain reactions, will be discussed. 

Alltech Associates) in order to remove water and traces of oxygen. Analysis of the reaction products was made on-line in a gas chromatograph equipped with TC detector and 50 m long HP-PLOT AI2O3/KCI capillary column to separate the products. Conversion, yields, and selectivity were calculated on a molar basis. 

There is good agreement between the conversion, isomerisation and cracking yield calculations (full lines) and the experimental data (dots), Fig. 30. 

By assuming (i) that only the above reactions take place, plus the chemical absorption of CO2, (ii) that natural gas consists Just of CH4, (iii) that air consists of 0.80 mole fraction N2 and 0.20 mole fraction O2, and (iv) that the ratio of conversion of CH4 by processes (/) and (2) is controlled through admitting oxygen for reaction (2) by adding just enough air so that the mole ratio of N2 to H2 is exactly 1 3, consider the overall efficiency of a process in which 1 200 m (S.T.P.) of natural gas yields 1.00 metric ton of NH3. (a) How many moles of NH3 would be formed from each mole of natural gas if there were complete conversion of the natural gas subject to the stated assumptions (6) What percentage of the maximum yield calculated in (a) is the actual yield ... 

The vector p is a very useful and little appreciated quantity, giving the volume expansion factor 5 and allowing a simplified calculation of the fractional yields and conversions Xy required fix kinetic fitting. Notice also that this vector is available for each analysis. It can therefore be used in treating even single-point results such as those obtained in standard tests of catalysts, or elsewhere in the study of conversions. The calculation of the p vector and the corresponding corrected quantities of the output y vector should be a routine procedure in treating all analytical results. 

When analyzing kinetic data or designing a chemical reactor, it is important to state clearly the definitions of reaction rate, conversion, yield, and selectivity. For a homogeneous reaction, the reaction rate is defined either as the amount of product formed or the amount of reactant consumed per unit volume of the gas or liquid phase per unit time. We generally use moles (g mol, kg mol, or lb mol) rather than mass to define the rate, since this simplifies the material balance calculations. 

The weight fraction of one-chain loops in the polymerization system is defined as the percentage of primary molecules whose ends are connected directly to each The log-log plots of t vs. rms end-to-end distance of the primary chain at different functionalities and conversions yield puellel straight lines. The average least-squares slope of these lines is found to be -0.76, which is taken to be -3/4 for subsequent calculations. The standard deviation of the slope is 0.04. The relationship between 7 and rms end-to-end distemce is cast in Figure 8 aa a representation of the discovered relation... 

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