Abstract
The tremendous increase of plastic product consumption leads to the huge demand of plasticizers in plastic industry due to its important role in plastic production. However, due to health related problems of conventional plasticizers, there comes the requirement of non-toxic and eco-friendly plasticizers. Among of them, 1,2-cyclohexane dicarboxylate ester plasticizers are the prominent candidates. They are also commercially produced by BASF and other companies by carrying hydrogenation of corresponding phthalates with organic solvent and Ru catalyst. The using of organic solvent creates more chemical wastes that harm human health. In this study, RhNi/Al-SBA-15 was designed as the catalyst for phthalates hydrogenation in water. Nickel was chosen as the secondary metal catalyst to reduce the amount of rhodium used in phthalates hydrogenation. Due to the excellent catalytic activity of Rh, it helps to break the conjugated bonds of benzyl rings, and reduce them to cyclohexene rings, so Ni particles can further reduce the unsaturated rings to cyclohexane rings. Moreover, the introduction of Ni as a bimetallic catalyst system helps to increase the active sites of rhodium by decreasing the metal nanoparticle size. Aluminated mesoporous silica (Al-SBA-15) was used as the support for the bimetallic catalyst system, Al loaded on SBA-15 acted as Lewis acid sites that increased the adsorption potential of phthalates on support and therefore produced high reaction yield. The bimetallic catalysts on aluminated mesoporous silica were prepared by chemical fluid deposition (CFD) method to create uniform particles in the support channels. Also, water was selected as the solvent for this phthalates hydrogenation due to its eco-friendly, cheap and abundant characteristics. The cis-, trans- isomer ratio of hydrogenated products can be controlled by the reaction operation variables such as solvent types or solvent containing CO2.