Screening of new additives to heteropoly acid catalyst for Friedel–Crafts reaction by microwave heated HTS and by Gaussian process regression

Activity of heteropoly acid (HPA) catalyst for Friedel–Crafts reaction was promoted by Pt addition of which effect was discovered by means of microwave heated high-throughput screening (HTS) and Gaussian process regression (GPR). In the screening, activities of Na, Mg, Mn, Zn, Pd, Cs, Pr and W promoted HPA were measured, and every activity test using microwave irradiation required only 150 s. The results and physicochemical properties of these 8 elements were used to construct regression models by a radial basis function network (RBFN), a support vector machine, and GPR. The regression model by GPR predicted that Pt is an effective additive, which promotes the activity, and the activity was experimentally verified to be 8 times higher than that of the unpromoted HPA catalyst. The performance of the regression model by GPR was superior to those by RBFN or by SVM because an excellent effect of Pt addition was discovered only by GPR. In addition to the extrapolative prediction, advantages of GPR model are that the performance and accuracy of the regression model are increased by using expected improvement which can suggest the additional experiments necessary for the improvement of the regression model.

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► Catalyst screening was accelerated by microwave-HTS and Gaussian process regression (GPR).
► Regression model by GPR was superior to those by radial basis function network and support vector machine.
► Pt-HPA (heteropoly acid) showed 8 times higher activity than that of HPA for benzylation of anisole at 130 °C.