Dopamine Supported Hydrogenation Catalyst And Its Application

In this paper, based on the mechanism of dopamine oxidative self-polymerization, the silica surface was coated with poly(dopamine), using the catechol and nitrogen groups of poly(dopamine) catalyst immobilized on-to the modified silica surface. We prepared two different types of supported catalyst and used them for acrylonitrile-butadiene rubber hydrogenation research. The main contents were as follows.1. Through the dopamine modified the surface of silica, supported catalyst of PDA-SiO2-RhCl3was prepared. Supported catalyst was studied by Fourier Transform Infrared (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Scanning electron microscopy (SEM) and Energy dispersive X-Ray spectroscopy (EDX), respectively. The results showed that the dopamine was successfully polymerized to the surface of silica. Then using the catechol and nitrogen groups of poly(dopamine) catalyst immobilized on-to the modified silica surface. Finally the preparation supported catalyst of PDA-SiO2-RhCl3was used for hydroxy-terminated butadiene-acrylonitrile copolymer (HTBN) hydrogenation reaction, the effect of catalyst dosage, reaction time, reaction temperature, reaction pressure, glue concentration etc. on the hydrogenation process were researched, a product over98%hydrogenation degree was obtained. FT-IR, Nuclear magnetic resonance spectra (’H-NMR), gel permeation chromatography (GPC) were used to characterize the product and results showed that the number-average molecular weight (Mn), weight-average molecular weight (Mw) and polydispersity index (PDI) of hydrogenated HTBN were remain unchanged, indicating that the hydrogenation process had selective and no reduction of the nitrile groups.2. With the preparation of PDA-SiO2RhCl3supported catalyst for reduction got another kind of new type supported catalysts of PDA-SiO2Rh. Supported catalyst was studied by XRD, XPS, SEM and EDX, respectively. The results showed that the catalyst was successfully immobilized on-to the modified silica surface. Then the preparation supported catalyst of PDA-SiO2Rh was used for HTBN hydrogenation reaction, the effect of catalyst dosage, reaction time, reaction temperature, reaction pressure etc. on the hydrogenation process were researched. Furthermore, recycle and reuse of the supported catalyst of PDA-SiO2Rh was studied. Results showed that after the supported catalyst of PDA-SiO2Rh recycled five times, the morphology of it kept good and also had high catalytic activity. FT-IR,1H-NMR and GPC were used to characterize the product and results showed that the hydrogenation process had selective and no destruction of the nitrile groups.