Biphenyl bridged dinuclear iron complex and its preparation method and use method

Abstract

The invention relates to a biphenyl bridged dinuclear iron complex, a preparation method and a use method thereof. The technical scheme is as follows: benzidine reacts with substituted salicylaldehyde to prepare ligand L, and then reacts with ferrous chloride and ferrous bromide respectively to prepare biphenyl bridged dinuclear iron complex D. The prepared biphenyl bridged dinuclear iron complex D catalyzes ethylene polymerization under the action of methylaluminoxane to prepare high molecular weight polyethylene with a broad peak distribution (Mw / Mn=3~7), and the catalytic activity is 106gPE / (molCat h), the weight average molecular weight is as high as 1.4 million. The invention has the characteristics of low raw material price, simple process, high yield and environmental friendliness, and the prepared biphenyl bridged dinuclear iron complex D is used as the main catalyst to catalyze olefin polymerization, requiring less catalyst amount, high polymerization activity and industrial application bright future.

Description

technical field [0001] The invention belongs to the technical field of iron complexes. It specifically relates to a biphenyl bridged dinuclear iron complex and a preparation method and application method thereof. Background technique [0002] The development of olefin industry is one of the main indicators to measure the development of a country's petrochemical industry. Polyolefin materials are currently the world's largest polymer material products, and have been widely concerned by industry and academia. The core of polyolefin material synthesis is catalyst and polymerization process. For mononuclear catalysts, whether it is a metallocene catalyst or a non-metallocene FI catalyst, there is only a single active center. Although the activity of the catalyst, the stereoregularity of the polymer, and the molecular weight can be controlled by changing the ligand structure, the molecular weight distribution of the polymerized product is narrow (Mw / Mn<3), and processing is ...

AI Technical Summary

Problems solved by technology

[0003] "α-Diimine Nickel Olefin Polymerization Catalyst and Its Preparation and Application" (CN 102060944 A) discloses a class of α-diimine nickel olefin polymerization catalysts, which are used to catalyze ethylene polymerization, and its catalytic activity is as high as 10 7 g PE / (molNi h), and the weight average molecular weight of the obtained polyethylene is only 10 4 g / mol, low molecular weight, far from meeting the requirements of industrial applications; in order to overcome the low molecular weight defect of polyethylene obtained by catalyzing this type of catalyst, "Alpha-diimine palladium olefin polymerization catalyst containing ortho-phenyl substitution and its preparation and application" (CN 103102433 A) patented technology increases the molecular weight of the polymer by introducing a large steric hindrance group to the ortho position of the imine group, although the weight average molecular weight of the polymer is increased to 10 5 g / mol, but its catalytic ethylene polymerization activity is reduced to 10 6 g PE / (molPd h), and the molecular weight distribution of polyethylene obtained by catalysis of this type of catalysis is less than 2, making the processing of polyolefin materials difficult; and the preparation process of this type of catalysis is complicated and expensive, which is not conducive to industrial production

[0004] "An olefin polymerization catalyst and its preparation method and application" (CN 103613690 A) discloses a class of Ziegler-Natta catalysts, the main catalyst of which is composed of a magnesium halide carrier, a transition metal halide, a monohydric alcohol less than C5, and an organosilicon compound The mixed system composed of organophosphorus compound and organoboron compound is used for catalytic polymerization of ethylene under the action of cocatalyst organoaluminum compound, and its catalytic activity is 10 4 g PE / (g cat), low activity; and this type of catalyst has defects such as many components, complicated process and high cost

[0005] "A bidentate titanium-based olefin polymerization catalyst and its preparation method" (CN 102977238 A) discloses a bidentate mononuclear titanium-based olefin polymerization catalyst and a bidentate oxygen-bridged dinuclear titanium-based olefin polymerization catalyst. The molar ratio of the catalyst methylaluminoxane is 2000:1 to form a catalytic system for catalyzing ethylene polymerization, and high molecular weight polyethylene can be obtained, with a molecular weight of 10 6 g / mol, but its catalytic activity is 10 5 g PE / (molTi h), the activity is not high, and the cost of titanium-based catalysts is high and the preparation conditions are harsh

[0006] A class of iron imine complexes with pyrimidine as the parent developed by Britovsek et al. (Britovsek G J P, Bruce M, Gibson V C, et al. , and Polymerization Studies.Journal of the American Chemical Society, 1999,121(38):8728-8740), using methylaluminoxane as a cocatalyst, the catalytic activity of ethylene polymerization can reach 6×10 6 g PE / (molFe h), while imine iron complexes with carbazole as the parent have no ethylene polymerization activity; in 2004, Bluhm et al. reported that pyridine imine iron complexes catalyzed ethylene polymerization (Bluhm M E, Folli C, M.New Iron-based Bis(imino)pyridine andAcetyliminopyridine Complexes as Single-site Catalysts for the Oligomerization ofEthylene.Journal ofMolecular Catalysis A:Chemical,2004,212(1-2):13-18), in methylaluminoxane Under the action, when the ethylene pressure is 0.3MPa, only C 4 ~C 18 oligomers; when the ethylene pressure was increased to 3MPa, only low molecular weight polymers were obtained, showing poor catalytic performance

[0007] In 2008, the bridged pyridine tetraimide dinuclear iron complex synthesized by Sun Junquan et al. 3 for EthylenePolymerization.Inorganica ChimicaActa, 2008,361 (7): 1843-1849), under the effect of methyl aluminoxane, catalyzed ethylene polymerization shows higher activity, can obtain broad peak, high molecular weight polyethylene, but this kind The preparation of the catalyst is difficult and the yield is low

Images