Establishment Of Styrene Dimerization Catalytic System And The Research Of Silane Coupling Agent Modification PGS/Polystyrene Composite Materials

Catalytic dimerization of aryl alkenes complete the preparation of new compoundsby constructing a new C–C bond in the synthesis of organic and fine chemicals, whichattract the academic and industrial attention. Traditional methods always use largeamounts of Bronsted or Lewis acid and transition metal catalysts, although thesemethods are efficient, drastic reaction conditions （up to130℃,24h） are alwaysemployed resulting in low selectivity and low turnover of frequency （TOF）（43.5mol/mol/h）. Additionally, the need of expensive phosphorus ligands and additives, aswell as generation of oligomers or polymers can be a significant drawback. Fromingan environmental, efficient, economic catalyst system is attracted for solving theproblem in recent years. As is known to all, dimerization of styrene on thepolymerization of styrene is of important theoretical significance. Polystyrene withgood mechanical properties, corrosion resistance and processing properties forapplications of Silane modified fiber-like palygorskites have been the hot topic,especially the silane coupling agent surface modification playing a crucial role.Basing on green chemistry, the dissertation is divided into two pats includinghighly efficient Pd（acac）₂/TFA catalyzed dimerization of vinylarenes andperformance study and the preparation of-two carbonyl organic silane couplingagent and fiber-like palygorskites/polystyrene composite materials of application. Ithas the following characteristics:1. we explored a high selectivity and efficiency of the head-to-tail dimerization ofstyrene1,3-diaryl-1-butenes under very mild reaction conditions. The reaction wasperformed in the presence of Pd（acac）2without any additional phosphorus ligand atambient temperature. TFA was employed for accelerating dimerization, as well asCH2Cl2which was used as solvent. In the course of our study, it was found that TFAis indispensable and the dimerization of styrene is100%atom economic reaction,that is, all of the atoms in the starting materials are incorporated into the products. It isworthy of note that the generation of dimers from vinylarenes occurs rapidly withoutgiving any oligomers and polymers.2. we prepared-two carbonyl organic silane coupling agent that have coordination chelating with cooperation to producing coplanar force and increasecohesiveness by two-steps. Silane modified palygorskites clay/polystyrene compositematerials were also prepared by blending method. It is worth to note that, as the silanemodified palygorskite clay content is3%, the palygorskite clay is well dispersed inthe polystyrene resin matrix, which has best mechanics property, such as, flexuralstrength and hardness, and so on.