Researches on the In Situ Copolymerization of Ethylene with Catalysts Immobilized onto the Molecular Sieves

In this paper,the bi-functional catalyst system composed of molecular sieve（MCM-41） immobilized oligomerization catalyst（C25H17Cl2N3·FeCl2） and copolymerization catalyst（Et（Ind）2ZrCl2） was employed in the in situ copolymerization of ethylene aiming to prepare the Linear low density polyethylene（LLDPE）.In this paper,we mainly argued the regular pattern of the in situ copolymerization of ethylene in limited nano-space and compared it with that happening in free space.The impact of variance of the reaction temperature,Fe/Zr value and the A1/（Fe＋Zr） value on the activity of the in situ copolymerization of ethylene has also been introduced.Furthermore,the degree of branching,thermal properties and crystalline changes of the obtained polymerization products prepared from different reactivity were investigated.

Synthesis of End Functional Polymers via Atom Transfer Radical Polymerization in Immobilized Catalytic System

Cross-linked polystyrene with azo-crown ether functional side chain (PSt-1, 10-dicarbonyl-3,6,9-trizaoeylcode-cane) was prepared under microwave irradiation and the structure was characterized through FT-IR and element analysis. The functionalized cross-linked polystyrene (cross-link degree, 3.5%) combining with immobilized catalyst system (CuBr and ethylα-bromo-isobutyrate) can catalyze atom transfer radical polymerization of Styrene. Neat polymer products can be obtained then. Complex of La and the polymer end group (EBiB) was synthesized. The third order nonlinear optical property of the polymer-La complex was investigated and the structure was also characterized by FT-IR and XPS.

Recoverable Mn~Ⅲ (salen) supported on diamine modified zirconium poly(styrene-isopropenyl phosphonate)-phosphate as an efficient catalyst for epoxidation of unfunctionalized olefins

Chiral Mn Ⅲ (salen) (Jacobsen's catalyst) was axially immobilized onto a new type of organic polymer-inorganic hybrid materialzirconium poly(styrene-isopropenyl phosphonate)-phosphate(ZPS-IPPA) with different linkage lengths and evaluated as catalysts for the epoxidation of unfunctionalized olefins. The results demonstrated that the prepared catalysts exhibited moderate to good activity and enantioselectivity in the asymmetric epoxidation of unfunctionalized olefins. Furthermore, the immobilized catalysts were relatively stable and could be conveniently separated from the reaction system by simple precipitation in hexane. Moreover, higher enantioselectivity was obtained with catalyst 2c than that of homogeneous counterpart catalyzed even after eight times. The excellent recycling of the catalyst was attributed to its structure feature of ZPS-IPPA which is different from either pure polystyrene or pure zirconium phosphates.

A mini review on strategies for heterogenization of rhodium-based hydroformylation catalysts

Hydroformylation has been widely used in industry to manufacture high value-added aldehydes and alcohols, and is considered as the largest homogenously catalyzed process in industry. However, this process often suffers from complicated operation and the difficulty in catalyst recycling. It is highly desirable to develop a heterogeneous catalyst that enables the catalyst recovery without sacrificing the activity and selectivity. There are two strategies to afford such a catalyst for the hydrofromylation： immobilized catalysts on solid support and porous organic ligand （POL）-supported catalysts. In the latter, high concentration of phosphine ligands in the catalyst framework is favorable for the high dispersion of rhodium species and the formation of Rh-P multiple bonds, which endow the catalysts with high activity and stability respectively. Besides, the high linear regioselectivity could be achieved through the copolymerization of vinyl functionalized bidentate ligand （vinyl biphephos） and monodentate ligand （3vPPh3） into the catalyst framework. The newly-emerging POL-supported catalysts have great perspectives in the industrial hydroformylation.

Response of bioaerosol cells to photocatalytic inactivation with ZnO and TiO_(2)impregnated onto Perlite and Poraver carriers

Bioaerosols are airborne microorganisms that cause infectious sickness,respiratory and chronic health issues.They have become a latent threat,particularly in indoor environment.Photocatalysis is a promising process to inactivate completely bioaerosols from air.However,in systems treating a continuous air flow,catalysts can be partially lost in the gaseous effluent.To avoid such phenomenon,supporting materials can be used to fix catalysts.In the present work,four photocatalytic systems using Perlite or Poraver glass beads impregnated with ZnO or TiO_(2)were tested.The inactivation mechanism of bioaerosols and the cytotoxic effect of the catalysts to^bioaeros^ls were studied.The plug flow photocatalytic reactor treated a bioaerosol flow of 460×10^(6)cells/m^(3)_(air)with a residence time of 5.7 s.Flow Cytometry(FC)was used to quantify and characterize bioaerosols in terms of dead,injured and live cells.The most efficient system was ZnO/Perlite with 72%inactivation of bioaerosols,maintaining such inactivation during 7.5 h due to the higher water retention capacity of Perlite(2.8 mL/gpcriite)in comparison with Poraver(1.5 mL/gperiite).However,a global balance showed that Ti0_(2)/Poraver system triggered the highest level of cytotoxicity to bioaerosols retained on the support after 96 h with 95%of dead cells.SEM and FC analyses showed that the mechanism of inactivation with ZnO was based on membrane damage,morphological cell changes and cell lysis;whereas only membrane damage and cell lysis were involved with Ti0_(2).Overall,results highlighted that photocatalytic technologies can completely inactivate bioaerosols in indoor environments.