Characteristics and catalytic properties of [t-BuNSiMe2Flu]TiMe2/dMMAO catalyst dispersed on various supports towards ethylene/1-octene copolymerization

In the present study, the characteristics and catalytic properties of [t-BuNSiMe2Flu]TiMe2/dMMAO catalyst dispersed on various supports towards ethylene/1-octene copolymerization were investigated. First, the dMMAO was impregnated onto various supports, such as SiO2, SiO2–TiO2, and TiO2. Then, copolymerization of ethylene/1-octene was conducted with and without the presence of supports in different solvent mediums. The SiO2–TiO2 support exhibited the highest activity among all the supports. The high activity observed for the SiO2–TiO2 support can be attributed to fewer interactions between the support and dMMAO, as confirmed by XPS and TGA results. The different solvents can alter the nature of the catalyst in two ways: (i) changing the interactions between the support and cocatalyst and/or (ii) changing the form of active species i.e., active ion-pair and solvent-separated ion-pair, as seen in the homogeneous system. However, there was no effect with regards to activity of the solvent mediums employed for the homogeneous system. It is worth noting that the Ti-complex made possible high incorporation of 1-octene having the triblock (OOO) and diblock (EOO) copolymers. The properties of copolymers by means of GPC, DSC, and 13C NMR were further discussed in more detail.

Graphical abstractIn the present study, the characteristics and catalytic properties of [t-BuNSiMe2Flu]TiMe2/dMMAO catalyst dispersed on various supports towards ethylene/1-octene copolymerization were investigated. First, the dMMAO was impregnated onto various supports such as SiO2, SiO2–TiO2, and TiO2. Then, copolymerization of ethylene/1-octene was conducted with and without the presence of supports in different solvent mediums. It revealed that the SiO2–TiO2 support exhibited the highest activity among the other support. The high activity observed for the SiO2–TiO2 support can be attributed to fewer interactions between the support and dMMAO as confirmed by XPS and TGA results. It can be proposed that the different solvents can possibly alter the nature of catalyst in two ways; (i) changing the interaction between the support and cocatalyst and/or (ii) changing the form of active species i.e., active ion-pair and solvent-separated ion-pair as seen in the homogeneous system. However, there was no effect with regards to activity of the solvent mediums employed for the homogeneous system. It is worth noting that the Ti-complex rendered pronouncedly high incorporation of 1-octene having the triblock (OOO) and diblock (EOO) copolymers. The properties of copolymer by means of GPC, DSC, and 13C NMR were further discussed in more details.Figure optionsDownload full-size imageDownload as PowerPoint slide