Hydrogenation of dioctyl phthalate over supported Ni catalysts

Di(2-ethylhexyl) hexahydrophthalate, an environmentally benign plasticizer of polyvinylchloride, could be produced through the hydrogenation of dioctyl phthalate (DOP). The hydrogenation of DOP was compared to that of toluene in this work by using supported nickel catalysts. While the surface acid/base properties significantly affected the activity of toluene hydrogenation, such effect was absent for the hydrogenation of DOP. Such different behavior might be due to the different electron charge distributions among the atoms in the two molecules. Thus, the active nickel surface area and pore size of catalysts might be the two major factors affecting the activity of hydrogenation of DOP.

Graphical abstractWhile the hydrogenation of aromatic ring in toluene was significantly affected by the surface acid/base properties of supported Ni catalysts, the hydrogenation of that in dioctyl phthalate (DOP) was not affected at all. Calculated Mulliken charges indicate that the difference might be caused by the different charge distributions.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Hydrogenation of dioctyl phthalate (DOP) over supported nickel catalysts. ► Acidity/basicity affected the activity of hydrogenation of toluene significantly. ►Acidity/basicity did not affect the activity of hydrogenation of DOP. ►Charge distributions of reactants determined the effects of acidity/basicity.