Alpha-diamino palladium catalyst as well as preparation method and application thereof

Abstract

The invention discloses an alpha-diamino palladium catalyst as well as a preparation method and application thereof. The structural formula of the alpha-diamino palladium catalyst is shown as a formula I. In the formula I, R represents methyl or isopropyl. The invention also provides a preparation method of the alpha-diamino palladium catalyst and application of the alpha-diamino palladium catalyst in ethylene oligomerization reaction. The alpha-diamino palladium catalyst provided by the invention is simple in structure and easy to prepare, has very strong chain walking capability, can catalyze ethylene oligomerization to obtain a product with higher long-chain branch content, has better low-temperature flowing property, and can be used as lubricating oil base oil.

Description

technical field [0001] The invention relates to the technical field of olefin catalytic polymerization. More specifically, it relates to an α-diamine-based palladium catalyst and its preparation method and application. Background technique [0002] Poly-α-olefin (Poly-α-olefin, PAO) synthetic base oil has excellent viscosity-temperature performance, low-temperature fluidity and anti-oxidation stability, and has been widely used in the lubrication of automobiles and other machinery. The reason why PAO lubricating base oil has excellent viscosity-temperature performance and low-temperature fluidity is that it has a highly branched structure, especially with a high content of long-chain branches. At the same time, PAO lubricating oil base oil not only does not contain aromatics, nitrogen, sulfur and other easily oxidizable impurities, but also does not contain terminal double bonds after catalytic hydrogenation, so it has excellent anti-oxidation stability. [0003] At presen...

AI Technical Summary

Problems solved by technology

For example, α-diimine palladium catalyst can catalyze ethylene polymerization under 1 atmospheric pressure, obtain oily hyperbranched polyethylene, although the branching of product is very high, mainly be methyl branch in the product, the content of long chain branch ( C≥6) is relatively low (usually ≤20mol%), so its low-temperature fluidity is poor (high pour point), which cannot meet the requirements of lubricating base oils

Low ethylene pressure significantly reduces the activity of the catalyst; increasing the ethylene pressure, although the catalyst activity increases, but the chain walking rate decreases, the degree of branching of the product decreases significantly and the molecular weight increases, resulting in a higher pour point of the oil and extremely low temperature fluidity. Poor, difficult to use as lubricant

For example, the α-diimine nickel catalyst carries out ethylene polymerization at 1 to 30 atmospheres. As the ethylene pressure increases, the molecular weight of the product increases, and the highest molecular weight of the product reaches 5×10 5 g / mol, but the product is solid powder and cannot be used as a lubricating oil

[0005] In addition, in the process of directly preparing polyolefin oil by ethylene oligomerization, the chain transfer method is mainly β-H elimination, and the obtained product usually contains unsaturated double bonds, which affects the anti-oxidation stability of the oil.

Therefore, the oligomerization product must be subjected to catalytic hydrogenation saturation treatment, which will lead to the complexity of the preparation process

For example, direct polymerization of α-diimine nickel catalyst and olefinic monomers to prepare highly branched polyolefin oils, and heteroatom-assisted α-diimine nickel catalyzed polymerization of ethylene to prepare branched polyolefin oils, the products are all It has a relatively high content of double bonds, and the bromine value is mostly above 30g / 100g. If it is used as a lubricating oil, it must be hydrogenated and saturated, which makes the preparation process more complicated.

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