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Effect of inorganic oxide supports on the activity of chromium‐based catalysts in ethylene trimerization
Author(s) -
Fallahi Maryam,
Ahmadi Ebrahim,
Mohamadnia Zahra
Publication year - 2019
Publication title -
applied organometallic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 71
eISSN - 1099-0739
pISSN - 0268-2605
DOI - 10.1002/aoc.4975
Subject(s) - chemistry , catalysis , chromium , ethylene , methylaluminoxane , nuclear chemistry , heterogeneous catalysis , desorption , ethylene oxide , yield (engineering) , iminodiacetic acid , adsorption , inorganic chemistry , organic chemistry , polymer , chelation , metallocene , polymerization , metallurgy , materials science , copolymer
Novel heterogeneous catalysts were prepared using immobilization of bis(2‐decylsulfanylethyl)amine–CrCl 3 (Cr‐SNS‐D) on various supports, namely commercial TiO 2 , Al 2 O 3 and magnetic Fe 3 O 4 @SiO 2 nanoparticles, to yield solid catalysts denoted as support@Cr‐SNS‐D. The structure of the catalysts was confirmed on the basis of spectroscopic analyses, N 2 adsorption–desorption and inductively coupled plasma (ICP) analysis. The surface areas of Al 2 O 3 @Cr‐SNS‐D, Fe 3 O 4 @SiO 2 @Cr‐SNS‐D and TiO 2 @Cr‐SNS‐D catalysts were determined to be 70, 23 and 41 m 2 g −1 , respectively. A decrease in surface area from that of the supports clearly establishes accurate immobilization of Cr‐SNS‐D catalyst on the surface of the parent carriers. The loading of Cr was determined to be 0.02, 0.16 and 0.11 mmol g −1 for Cr‐SNS‐D supported on TiO 2 , Al 2 O 3 and Fe 3 O 4 @SiO 2 , respectively, using ICP analysis. After preparation and full characterization of the catalysts, ethylene trimerization reaction was accomplished in 40 ml of dry toluene, at 80°C and 25 bar ethylene pressure and in the presence of methylaluminoxane (Al/Cr = 700) within 30 min. The supported chromium catalysts were found to be efficient and selective for the ethylene trimerization reaction. The highest activity (74 650 g 1‐hexene g Cr −1 h −1 ), as well as no polyethylene formation during reaction processes, was observed when TiO 2 was used as the catalyst support.