An efficient, simple and solvent-free method for highly regioselective N-alkylation of benzotriazole in the presence of SiO 2 , K 2 CO 3 and tetrabutylammonium bromide (TBAB) under thermal and microwave conditions has been described. In this method, 1-alkyl benzotriazoles were obtained regioselectively in moderate to high yields and short reaction times.
Polyethylene reactor alloys are synthesized through heterogeneous ethylene polymerization with a new type of Ziegler-Natta (ZN)/late transition metal (LTM) hybrid catalyst. The effect of various parameters including catalyst composition (LTM/ZN ¼ 0.01, 0.02, 0.04), polymerization temperature (TP ¼ 30, 30-60, 60 8C) and loading temperature (TL ¼ 30, 60 8C) on catalyst activity, chain's vinyl content, viscosity average molecular weight (M v ) and thermal properties are investigated. Two distinct melting peaks were observed in the ranges of 110-140 8C and 60-90 8C, indicating presence of two different lamellar structures. LTM/ZN ratio shifted melting peaks toward lower values. Rheological properties confirmed homogeneity of polymer blend's microstructure as they follow time temperature superposition.Macromol. React. Eng. 2015, 9, 8-18 wileyonlinelibrary.com
PolymerizationCatalyst component handling and polymerization procedures were carried out as previously described. [47] Polymerization reactions were performed in a 150 ml steel reactor equipped with controlling Scheme 1. Structure of late transition metal catalyst.
In this study, the copolymerization of ethylene with nonconjugated diene (5-ethylidene-2-norbornene) was carried out with a bis(2-PhInd) ZrCl 2 metallocene catalyst. Some polymerization factors that were considered affective on the catalyst activity, including comonomer content in the feed, ethylene pressure, and polymerization temperature, were investigated via response surface methodology to determine the optimum polymerization conditions. We found that the comonomer content in the feedstock had no enormous effect on the catalyst activity depression. Also, the polymerization temperature increment through the scrutinized range decreased the copolymerization activity.
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