Phosphine nitrogen coordination type metal catalyst and application thereof

Abstract

The invention relates to a phosphine nitrogen coordination type metal catalyst and application thereof. The phosphine nitrogen coordination type metal catalyst uses PCmN as a main body skeleton; a chemical general formula is [R1R2PCmNH(R3)]MXn, and m is equal to 2 or 3; a structural formula is shown as a formula I; the metal catalyst is obtained by performing a coordination reaction of a ligand R1R2PCmNH(R3) and a metal compound MXn, wherein M is equal to 2 or 3, M is one of Ti, Zr, Hf, V, Cr, Fe, Co or Ni; X is F, Cl, Br, I or carbonyl; n is equal to 2 to 6; P and N are coordination atoms, R1, R2 and R3 can be modulated and can be electron-donating groups, and can also be electron-withdrawing groups, so as to regulate and control an electron effect and a stereo-hindrance effect around thecenter of metal. By utilizing the phosphine nitrogen coordination type metal catalyst, high-selectivity preparation of 1-hexene and 1-octylene can be implemented, and the maximum sum of mass fractions of two linear alpha-olefins can exceed 95%; by modulation on a phosphine nitrogen group, production of ethylene oligomerization products 1-C6 and 1-C8 which have different output ratios is implemented.

Description

technical field [0001] The invention belongs to the field of metal organic catalysts, in particular to a phosphine nitrogen coordination metal catalyst and its application. Background technique [0002] α-olefin is a very important organic raw material and chemical intermediate, which is widely used in the synthesis of copolymerized polyethylene, surfactants, advanced synthetic lubricants (polyα-olefins), plasticizers and fine chemicals. [0003] Among them, 1-hexene and 1-octene are mainly used as comonomers for polyethylene, and 1-octene is also used as a raw material for polyalphaolefin (PAO). With the increasing demand for high-end polyolefin (POE) and synthetic lubricating oil (polyα-olefin), 1-hexene and 1-octene have become the main growth points of the α-olefin market, accounting for 30% of the total demand about. [0004] Compared with traditional wax cracking, extraction and separation, alkane catalytic cracking, alkane dehydrogenation, coal extraction, fatty alc...

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Problems solved by technology

[0007] In the existing ethylene oligomerization process, the preparation of the catalyst is carried out in a batch manner. Under the protection of high-purity nitrogen, each component of the catalyst is diluted to a certain concentration with the dehydrated cyclohexane from the dehydration tower in the catalyst preparation tank, and then passed through the respective metering The pump controls the flow rate and injects it into the reaction system according to the given ratio; the reaction temperature is 115°C, the reaction pressure is 5.0MPa, the residence time is 1.0h, and the product distribution: butene 0.07wt%, 1-hexene 94.39wt%, octane 0.29wt% ene and 5.25wt% decene, the catalyst system can produce 1-hexene with high selectivity, but cannot selectively produce 1-octene

[0008] Another Carter et al. (High activity ethylene trimerisation catalysts based ondiphosphine ligands.Chem.Commun.2002,858) reported a chromium catalyst using chromium trichloride, PNP ligands (methoxyphenyl on P) and formazan In the system composed of aluminoxane (MAO), the selectivity of 1-hexene is close to 90%, and the catalytic activity is 1030kg / (g Cr h), but this catalyst system cannot produce 1-octene with high selectivity, and The synthesis steps of its ligands are relatively cumbersome

[0009] There are relatively few reports on the preparation of 1-octene by ethylene oligomerization with high selectivity. Bollmann et al. reported that in ethylene oligomerization, by (R 2 ) 2 PN(R 1 )P(R 2 ) 2 (PNP) ligand, chromium trichloride and methylaluminoxane (MAO) catalyst, the selectivity of 1-octene is up to about 70wt%, the selectivity of terminal olefins is above 90%, however, the ethylene The selectivity of the tetramerization system does not reach the selectivity of more than 90% of the trimerization of ethylene

[0010] In the prior art, by changing the skeleton structure of the PNP ligand, a series of derived ligands based on P and P coordination have been obtained, such as the PNNP skeleton ligand, PC n P-skeleton ligand, PNC n NP framework ligands, PCNCP framework ligands, etc., form a catalytic system with chromium source, but the catalytic reactivity and 1-octene selectivity have not been significantly improved, and the synthesis steps of the ligands are more complicated.

[0011] At present, there is no industrial production of ethylene tetramerization to prepare 1-octene in China, and there is no particularly mature catalyst system

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