Screening of variables in a Willgerodt-Kindler synthesis

As a reaction mechanism is not known, it is not possible to deduce how the experimental conditions should be controlled to maximize the yield. 

Evaluation of the massive amount of literature data available, indicated that the variables shown in Table 6.6 could influence the yield. 

The reaction occurrs in a heterogeneous system in which flowers of sulfur is suspended. The variables x and Xj were included to take the heterogeneity of the system into acount. 

A 2 fractional factorial design (I = 12345) was used to estimate the model parameters. The design has a Resolution V and the desired parameters can be estimated free from confoundings with each other. The design matrix and the yields (%), y, obtained are given in Table 6.7. 

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