Ethylideneacenaphthylene bis unsymmetrical alpha-diimine intermediates, methods of making and using the same

Abstract

This invention discloses a biasymmetric α-diimide intermediate of ethylacenaphthene, as well as a catalyst prepared therefrom, the intermediate, a method for preparing the catalyst, and its applications. Using 2,4,6-tri-tert-butylaniline as a raw material, the reaction is carried out in the presence of a catalyst at 120°C to obtain a biasymmetric α-diimide chemical intermediate of ethylacenaphthene as shown in Formula I. Compared with existing technologies, this invention uses readily available, inexpensive, and easily stored 2,4,6-tri-tert-butylaniline as a reaction raw material instead of expensive and demanding 2,4-di-tert-butylaniline, effectively reducing the raw material procurement threshold and overall production costs, and simplifying storage conditions. The method of this invention uses readily available raw materials, is low-cost, simple to operate, and has a high yield, making it suitable for industrial-scale production.

Description

Technical Field

[0001] This invention relates to the field of chemical synthesis technology, and more specifically, to an ethylene acenaphthene biasymmetric α-diimide intermediate, as well as catalysts prepared therefrom, intermediates, methods for preparing catalysts, and applications. Background Technology

[0002] Ethylene acenaphthene biasymmetric α-diimine is an important chemical ligand or intermediate. As a core raw material, it can be used to synthesize high-value metal complex catalysts and special compounds for pharmaceutical and other fields.

[0003] Based on a related collaborative research and development project, this invention often requires the use of this compound as a key raw material. The inventors have innovatively developed a synthetic process route for this intermediate.

[0004] Generally, based on chemical reaction principles and formulas, the synthesis of the ethyleneacenaphthene bisasymmetric α-diimine intermediate can be achieved using 2,4-di-tert-butylaniline as the direct starting material. However, in practice, the inventors found that while 2,4-di-tert-butylaniline is commercially available, its market price is relatively high, and the substance requires stringent storage conditions (such as low temperature, protection from light, and inert gas protection), making long-term preservation difficult. This presents a significant obstacle to the synthesis of the ethyleneacenaphthene bisasymmetric α-diimine intermediate, namely, high raw material acquisition costs and difficulties in storage.

[0005] To address the issues of high raw material acquisition costs and storage difficulties, those skilled in the art might attempt to synthesize 2,4-di-tert-butylaniline themselves. However, this would undoubtedly prolong the overall synthetic route, increasing process complexity and production costs.

[0006] Therefore, there is an urgent need to find low-cost and easy-to-store raw materials for the synthesis of ethyleneacenaphthene biasymmetric α-diimine chemical intermediates. Summary of the Invention

[0007] To address the aforementioned technical problems, the inventors innovatively employed 2,4,6-tri-tert-butylaniline as the reaction raw material. Compared to 2,4-di-tert-butylaniline used in conventional approaches, 2,4,6-tri-tert-butylaniline offers significant comprehensive advantages: its market price is far lower (only about 1 / 7 to 1 / 10 of the latter), its storage conditions are more flexible (no need for low-temperature or inert gas protection, room temperature sealed storage is sufficient), and its market supply is stable and procurement is convenient. 2,4,6-tri-tert-butylaniline differs from 2,4-di-tert-butylaniline in molecular structure. Due to the strong stereoshiking effect generated by the two ortho-tert-butyl groups, the reactivity of the nitrogen atom and aromatic ring of 2,4,6-tri-tert-butylaniline is significantly reduced. However, the inventors of this application unexpectedly discovered that when 2,4,6-tri-tert-butylaniline is used as a raw material for ketamine condensation reactions, the ortho-tert-butyl substituents are removed, even under conventional ketamine condensation conditions. This enabled 2,4,6-tri-tert-butylaniline to successfully substitute for 2,4-di-tert-butylaniline in the reaction and generate the target product—ethyleneacenaphthene biasymmetric α-diimide chemical intermediate.

[0008] This discovery provides a novel technical route for the synthesis of ethyleneacenaphthene biasymmetric α-diimine intermediates, effectively avoiding the problems of high raw material costs, demanding storage conditions, and unstable supply associated with using 2,4-di-tert-butylaniline. No existing technology discloses any method for preparing ethyleneacenaphthene biasymmetric α-diimine intermediates using 2,4,6-tri-tert-butylaniline as a raw material. Therefore, developing a method for the efficient and reliable synthesis of ethyleneacenaphthene biasymmetric α-diimine intermediates based on 2,4,6-tri-tert-butylaniline is of great significance for reducing dependence on 2,4-di-tert-butylaniline, lowering production costs, simplifying storage conditions, and ultimately achieving stable and economical preparation of this intermediate.

[0009] One objective of this invention is to provide a method for preparing a biasymmetric α-diimine chemical intermediate, ethylacenaphthene. This method uses 2,4,6-tri-tert-butylaniline as the starting material and successfully synthesizes the target product by controlling specific reaction conditions. This overcomes the shortcomings of existing technologies using 2,4-di-tert-butylaniline, such as high raw material cost, harsh storage conditions, and unstable supply, and achieves low-cost, high-efficiency, and stable preparation of this chemical intermediate.

[0010] The second objective of this invention is to provide a chemical intermediate of ethylene acenaphthene biasymmetric α-diimine, the chemical formula and structural formula of which are shown in Formula I:

[0011] A third objective of this invention is to provide a method for preparing the intermediate shown in Formula I above, comprising the following steps: 1) Ethylene acenaphthene reacts with aniline containing a sterically hindered substituent via a ketamine condensation reaction to yield the compound shown in Formula III:

[0012] 2) The compound shown in Formula III reacts with 2,4,6-tri-tert-butylaniline via a ketamine condensation reaction to yield the intermediate shown in Formula I:

[0013] In some embodiments, the solvent used in step 1) above is selected from at least one of toluene, acetonitrile, acetic acid, and anhydrous ethanol. In some preferred embodiments, the solvent used in step 1) above is selected from toluene and acetonitrile.

[0014] In some embodiments, the catalyst used in step 1) above is selected from at least one of p-toluenesulfonic acid and acetic acid.

[0015] In some embodiments, in step 1) above, the ratio of the catalyst, ethylene acenaphthene, aniline with a large sterically hindered substituent, and solvent is 0.1-0.15 mmol: 1-1.1 mmol: 1-1.4 mmol: 5-10 mL.

[0016] In some implementations, the reaction time for step 1) above is 2-8 hours, preferably 3-6 hours.

[0017] In some embodiments, step 1) above further includes column chromatography of the product in a silica gel column using a mixed solvent of dichloromethane and petroleum ether or a mixed solvent of petroleum ether and ethyl acetate as eluent to obtain the product as shown in Formula III.

[0018] In some embodiments, in step 2) above, the ratio of reactant formula III, 2,4,6-tritert-butylaniline, zinc chloride and solvent is 0.5-1 mmol: 1.0-1.5 mmol: 1.0-1.5 mmol: 3-5 mL.

[0019] In some embodiments, the reaction temperature of step 2) above is selected from 110-120°C.

[0020] In some embodiments, the reaction time of step 2) above is selected from 20 min to 1 h, preferably 30 min to 40 min.

[0021] In some implementations, step 2) above further includes the following steps: After the reaction was complete, the reaction solution was cooled and filtered, and washed three times with isopropyl ether. The solid was dissolved in dichloromethane until clear and transparent, and 20 ml of hydrated potassium oxalate aqueous solution (0.15 mol / L) was added. The mixture was stirred vigorously for 30 min until a white precipitate of zinc oxalate appeared. The layers were separated, and the organic layer was washed three times with deionized water. The product was dried over anhydrous magnesium sulfate, filtered, rotary evaporated, and dried. The product was eluented with a mixture of dichloromethane and petroleum ether or a mixture of petroleum ether and ethyl acetate and then subjected to column chromatography on a silica gel column to obtain the product shown in Formula I.

[0022] A fourth objective of this invention is to provide a method for preparing a catalyst of formula II using an intermediate shown in formula I, comprising the following steps: under an inert gas atmosphere, complexing the intermediate compound shown in formula I with one of ethylene glycol dimethyl ether nickel dibromide, ethylene glycol dimethyl ether nickel dichloride, or nickel dichloride hexahydrate to obtain the catalyst shown in formula II. Wherein, X is chlorine or bromine. In one embodiment of this invention, X is bromine. In another embodiment of this invention, X is chlorine.

[0023] In one embodiment of the invention, under a nitrogen atmosphere, the compound shown in Formula I is used as a ligand, and the nickel-containing compound complexed with the ligand is selected as nickel dimethyl ether dibromide (DME)NiBr2, wherein the molar ratio of the ligand to (DME)NiBr2 is 1:1-1.2, preferably 1:1.1; the solvent is dichloromethane, the reaction temperature is 15-35°C, preferably 25°C, and the reaction time is 8-30 hours, preferably 16-24 hours.

[0024] The fifth objective of this invention is to provide a catalyst composition for catalyzing olefin polymerization, the composition comprising a main catalyst and a co-catalyst, wherein the main catalyst is selected from the catalyst shown in Formula II, the co-catalyst is selected from at least one of alkylaluminum chloride, alkylaluminum and aluminoxane, and the olefin is ethylene or propylene.

[0025] In a preferred embodiment, the catalyst composition comprises a main catalyst and a co-catalyst.

[0026] In one embodiment, the aluminum oxane in the above catalyst composition is methylaluminoxane (MAO), modified methylaluminoxane (MMAO), ethylaluminoxane, or isobutylaluminoxane.

[0027] In one embodiment, the alkylaluminum is trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-hexylaluminum, or tri-n-octylaluminum.

[0028] In one embodiment, the alkylaluminum chloride is diethylaluminum chloride, sesqui-diethylaluminum chloride, or ethylaluminum dichloride.

[0029] Considering the effectiveness and cost of the co-catalyst, in a preferred embodiment, the co-catalyst is alkylaluminum chloride, wherein the molar ratio of metallic aluminum in alkylaluminum chloride to metallic nickel in the catalyst is referred to as the aluminum-nickel ratio, and the aluminum-nickel ratio ranges from 50 to 2000:1.

[0030] The sixth objective of this invention is to provide the application of the catalyst shown in Formula I in the catalytic polymerization of ethylene and propylene to prepare polyethylene.

[0031] Compared with the prior art, the ethylene acenaphthene biasymmetric α-diimine chemical intermediate and its synthesis method provided by the present invention have the following beneficial effects: 1) Raw material costs are significantly reduced, and storage conditions are greatly simplified. This invention addresses the problems of high cost and demanding storage conditions associated with 2,4-di-tert-butylaniline, a key starting material in existing synthetic routes, by innovatively employing the structural analog 2,4,6-tri-tert-butylaniline as an alternative starting material. 2,4,6-tri-tert-butylaniline is a conventional chemical product with a stable market supply, a price significantly lower than 2,4-di-tert-butylaniline, and requires less stringent storage conditions, needing only sealed, cool, and dry storage. This alternative significantly reduces the raw material procurement threshold and overall production cost of the ethyleneacenaphthene biasymmetric α-diimide chemical intermediate, demonstrating excellent economic applicability and making it more suitable for industrial-scale production.

[0032] 2) The reaction conditions are mild and the operation is simple. The method of this invention does not rely on complex reaction equipment or harsh reaction conditions (such as extreme environments like high pressure) and can be successfully implemented in conventional reactors. The synthetic route is rationally designed, the steps are simple, and the technical requirements for operators are low, reducing the difficulty of process control and improving production efficiency.

[0033] 3) Simple post-processing and high yield The reaction system exhibits good selectivity and few side reactions, and the purification and separation process of the target product, ethyleneacenaphthene biasymmetric α-diimine, is simple and easy to perform. The method of this invention can achieve an ideal product yield (up to 39.9%), avoiding product loss caused by cumbersome post-processing steps and further improving the overall synthesis efficiency. Detailed Implementation

[0034] The present invention will be further described below with reference to specific embodiments, but the present invention is not limited to the following embodiments.

[0035] Example 1, Preparation of Compound III: p-Toluenesulfonic acid (0.34 g, 2 mmol) was added to a toluene (150 mL) solution of 2,6-bis(diphenylmethyl)-4-methylaniline (8.8 g, 20 mmol) and ethylenaclairone (4.16 g, 20 mmol), and the mixture was refluxed for 6 h. The solvent was removed, and the residue was subjected to silica gel column chromatography with a 2:1 volume ratio of dichloromethane and petroleum ether to obtain an intermediate of Formula III with a mass of 12.1 g, yield: 96.0%.

[0036] Example 2, Preparation of Chemical Intermediate of Formula I: Zinc chloride (0.20 g, 1.5 mmol) was added to a solution of 2,4,6-tri-tert-butylaniline (0.392 g, 1.5 mmol) and compound of Formula III (0.629 g, 1 mmol) in acetic acid (5 mL). The mixture was heated to 110-120 °C and reacted for 30 min. After cooling and filtration, the mixture was washed three times with isopropyl ether. The solid was dissolved in dichloromethane until clear and transparent. 20 mL of potassium oxalate hydrate solution (0.15 mol / L) was added, and the mixture was stirred vigorously for 30 min until a white precipitate of zinc oxalate appeared. The mixture was separated, and the organic layer was washed three times with deionized water. The solution was dried over anhydrous magnesium sulfate, filtered, and dried again by rotary evaporation. Silica gel column chromatography was performed using a 2:1 volume ratio of dichloromethane and petroleum ether to obtain the intermediate of Formula I with a mass of 0.340 g, yield: 41.6%.

[0037] Example 3, Preparation of Formula II catalyst: Under a nitrogen atmosphere, Formula I ligand (0.163 g, 0.2 mmol) and (DME)NiBr2 (0.062 g, 0.2 mmol) were dissolved in 20 mL of dichloromethane and stirred at room temperature for 24 hours. The dichloromethane was then dried under vacuum, and the solution was washed three times with 20 mL of diethyl ether each time. The diethyl ether was then dried under vacuum to obtain Formula II catalyst, 0.197 g, with a yield of 95%.

[0038] The following examples illustrate catalytic ethylene polymerization: Example 4: Ethylene pressure polymerization was carried out under anhydrous and oxygen-free conditions. The ethylene pressure was 0.7 MPa, and the polymerization temperature was 40 °C. 1 L of heptane was poured into a 2000 mL stainless steel reactor, followed by the injection of 1.5 mL of a 2.0 mol / L toluene solution of diethylaluminum chloride, a co-catalyst. 2 μmol of Formula II catalyst was dissolved in 10 mL of toluene solution and injected. The ethylene pressure was increased to 0.7 MPa, and the mixture was stirred. After reacting for half an hour, the polymer solution was poured into an acidified ethanol solution for sedimentation. The polymer was filtered, washed several times with acidified ethanol, and dried under vacuum at 60 °C to constant weight. 3.2 g of polymer was obtained. The catalytic activity was 3.2 × 10⁻⁶. 6 gPE[mol(Ni)h]-1 The weight-average molecular weight of the polymer product is 1.53 × 10⁻⁶. 6 g / mol, polydispersity index of 2.78, branching degree of 95.

Claims

1. An ethyleneacenaphthylene double asymmetric α-diimine chemical intermediate represented by Formula I: ###0001### Formula I X is chlorine or bromine; 。 2. A catalyst represented by the formula II, characterized by, The method for preparing the ethyleneacenaphthylene double asymmetric α-diimine chemical intermediate represented by Formula I from 2,4,6-tri-tert-butyl aniline comprises the following steps: 。 3. A process for the preparation of a chemical intermediate according to claim 1, characterized in that, 1) obtaining a compound represented by Formula III through a ketone amine condensation reaction between ethyleneacenaphthenequinone and aniline with a large steric hindering substituent group: 2) obtaining the intermediate represented by Formula I through a ketone amine condensation reaction between the compound represented by Formula III and 2,4,6-tri-tert-butyl aniline: ； The step 1) uses at least one of p-toluenesulfonic acid and acetic acid as a catalyst; the reaction temperature of the step 2) is 110-120°C. 。 4. The production method according to claim 3, wherein The method comprises the following steps: under the protection of inert gas, complexing the intermediate of claim 1 with one of ethylene glycol dimethyl ether nickel dibromide, ethylene glycol dimethyl ether nickel dichloride and nickel dichloride hexahydrate to obtain the catalyst of claim 2.

5. A process for the preparation of the catalyst of claim 2, characterized in that, The method comprises the following steps: under the protection of inert gas, complexing the intermediate of claim 1 with one of ethylene glycol dimethyl ether nickel dibromide, ethylene glycol dimethyl ether nickel dichloride and nickel dichloride hexahydrate to obtain the catalyst of claim 2.

6. A catalyst composition for catalyzing the polymerization of olefins, characterized in that, 7. Use of the catalyst of claim 2 in catalyzing the polymerization of ethylene or propylene to prepare polyethylene or polypropylene. ​

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