Isoprene cyclization trimerization catalyst, preparation method and application thereof

Abstract

The application discloses a kind of isoprene cyclization trimerization catalyst, it is characterized in that, the catalyst is composed of titanium-containing substance supported on graphene and alkyl aluminum chloride, the titanium-containing substance is 1-20% of graphene mass by titanium, and the mass ratio of alkyl aluminum chloride and titanium-containing substance supported on graphene is 2-20:1.The isoprene cyclization trimerization reaction is catalyzed by the catalyst, and there is no or little dimer by-product in reaction product.

Description

Technical Field

[0001] This invention relates to catalysts, preparation methods, and applications for synthesizing oligomers, and more specifically to isoprene cyclization trimerization catalysts, preparation methods, and isoprene cyclization trimerization methods thereof. Background Technology

[0002] Isoprene is one of the main olefins produced in petrochemical production processes and is an important organic chemical raw material with a wide range of applications. With the rapid development of science and technology and the continuous advancement of low-molecular-weight polymerization technologies for olefins, such as dimerization and trimerization, it has gained increasing attention. Among these, the trimerization and cyclization of isoprene to form trimethylcyclododecanetriene has the broadest application prospects and the highest industrial value.

[0003] Nanomaterials are star materials in the field of materials science, and graphene is one of the hottest research materials in recent years. With its tunable size, high hydrothermal stability, and large specific surface area, it has broad application prospects in catalysis, separation, biology, and nanomaterials. Summary of the Invention

[0004] The inventors of this invention discovered that, unexpectedly, under certain conditions, no dimerization byproducts are found in the reaction products of isoprene cyclization trimerization catalyzed by a heterogeneous catalyst composed of a titanium compound supported on graphene and alkyl aluminum chloride. Based on this, this invention was developed.

[0005] The purpose of this invention is to provide an isoprene cyclotrimerization catalyst, its preparation method, and an isoprene cyclotrimerization method, which are different from existing technologies.

[0006] To achieve the above objectives, the first aspect of the present invention provides an isoprene cyclization trimer catalyst, characterized in that the catalyst is composed of a titanium-containing material supported on graphene and an alkyl aluminum chloride, wherein the titanium-containing material has a mass content of 1-20% based on titanium, and the mass ratio of the alkyl aluminum chloride to the titanium-containing material supported on graphene is 2-20:1.

[0007] To achieve the above objectives, a second aspect of the present invention provides a method for preparing an isoprene cyclization trimer catalyst, characterized by comprising the following steps: the method includes mixing and reacting graphene, TiCl4 and light aromatic hydrocarbons and recovering the product, and then mixing it with alkyl aluminum chloride to obtain an isoprene cyclization trimer catalyst composed of a titanium-containing material supported on graphene and alkyl aluminum chloride.

[0008] To achieve the above objectives, a third aspect of the present invention provides a method for isoprene cyclization trimerization, characterized in that, under cyclization reaction conditions, isoprene is used as a raw material to carry out the cyclization reaction in contact with a catalyst, wherein the catalyst is composed of a titanium-containing substance supported on graphene and an alkyl aluminum chloride, wherein the titanium-containing substance has a mass content of 1-20% based on titanium, and the mass ratio of the alkyl aluminum chloride to the titanium-containing substance supported on graphene is 2-20:1.

[0009] The isoprene cyclization trimerization reaction provided by this invention produces no dimer byproducts under certain conditions, which is more conducive to the production of trimer products. Detailed Implementation

[0010] An isoprene cyclization trimer catalyst, characterized in that the catalyst is composed of a titanium-containing material supported on graphene and an alkyl aluminum chloride, wherein the titanium-containing material accounts for 1-20% of the mass of graphene based on titanium, and the mass ratio of the alkyl aluminum chloride to the titanium-containing material supported on graphene is 2-20:1, wherein the mass of the titanium-containing material supported on graphene refers to the total mass of the titanium-containing material and graphene.

[0011] In the catalyst of the present invention, preferably, the titanium-containing material accounts for 2-10% of the graphene mass based on titanium.

[0012] In the catalyst of the present invention, the alkyl aluminum chloride is sesquiethyl aluminum chloride and / or diethylaluminum chloride, and the mass content of the alkyl aluminum chloride is 50-95%, preferably 30-70%.

[0013] This invention also provides a method for preparing an isoprene cyclization trimer catalyst, comprising the following specific steps: under anhydrous and oxygen-free reaction conditions and nitrogen protection, graphene, TiCl4, and light aromatic hydrocarbons are mixed and reacted at 10-60°C for 4-24 hours with stirring; the mixture is then separated, washed, and dried to obtain a titanium-containing material supported on graphene; this material is then mixed with alkyl aluminum chloride to obtain an isoprene cyclization trimer catalyst composed of the titanium-containing material supported on graphene and alkyl aluminum chloride. Specifically, the weight ratio of graphene, TiCl4, light aromatic hydrocarbons, and alkyl aluminum chloride can be 1:5-20:10-200:20-100.

[0014] Graphene is a nanomaterial of carbon with tunable size, high hydrothermal stability, and large specific surface area, finding applications in catalysis, separation, biology, and nanomaterials. In this invention, the graphene is preferably obtained through supercritical exfoliation, with fewer than 10 layers, a sheet size of 0.5-5 micrometers, and an ash content of less than 0.1%.

[0015] In the preparation method of the present invention, the light aromatic hydrocarbon can be selected from benzene, toluene, ethylbenzene, xylene, etc., and toluene is preferred.

[0016] The present invention also provides an isoprene cyclization trimer catalyst obtained by the above preparation method.

[0017] The present invention further provides a method for the cyclization trimerization of isoprene, characterized in that the method involves contacting isoprene with a catalyst under cyclization reaction conditions; wherein the catalyst is composed of a titanium-containing substance supported on graphene and alkyl aluminum chloride, wherein the titanium-containing substance comprises 1-20% of the mass of graphene based on titanium, and the mass ratio of alkyl aluminum chloride to the titanium-containing substance supported on graphene is 2-20:1, wherein the mass of the titanium-containing substance supported on graphene refers to the total mass of the titanium-containing substance and graphene.

[0018] The cyclopolymerization reaction conditions are 30-80℃, preferably 35-70℃, and the mass ratio of catalyst to isoprene is 0.1-10:1, preferably 0.2-5:1.

[0019] The present invention will be further illustrated by the following examples, but these examples are not intended to limit the scope of the invention.

[0020] In the examples, gas chromatography was used to analyze the composition of the products after the reaction, and then the selectivity of the cyclic trimer was calculated according to the following formula.

[0021] Selectivity of cyclic trimer trimethyl-1,5,9-cyclododecanetriene = (mass of CDT in the product / total mass of the product) × 100%.

[0022] Examples 1-4 illustrate the catalysts and their preparation methods provided by the present invention.

[0023] Example 1

[0024] Under anhydrous and oxygen-free nitrogen protection conditions, 1.5 g of graphene, an appropriate amount of TiCl4 and 200 g of toluene were stirred and mixed, and the mixture was stirred and reacted at 40 °C for 12 h. After filtration, the mixture was washed three times with hexane, dried and mixed with 150 g of sesquiethylaluminum chloride to obtain heterogeneous catalyst X1.

[0025] Catalyst X1 contains 5.3% titanium, 18% titanium-containing material supported on graphene, and 82% sesquiethyl aluminum chloride.

[0026] Example 2

[0027] Under anhydrous and oxygen-free nitrogen protection conditions, 4.0 g of graphene, an appropriate amount of TiCl4 and 100 g of toluene were mixed and stirred at 50 °C for 20 h. After filtration, the mixture was washed three times with hexane, dried and mixed with 100 g of sesquiethylaluminum chloride to obtain heterogeneous catalyst X2.

[0028] Catalyst X2 contains 1.2% titanium, 13% titanium-containing material supported on graphene, and 87% sesquiethyl aluminum chloride.

[0029] Examples 3 and 4

[0030] Examples 3 and 4 correspond to Examples 1 and 2, respectively, except that the sesquiethylaluminum chloride is replaced by the same mass of diethylaluminum chloride, resulting in heterogeneous catalysts X3 and X4, respectively.

[0031] Examples 5-9 illustrate the isoprene cyclization trimerization method provided by the present invention.

[0032] Examples 5-8

[0033] Under nitrogen protection, 150 mL of toluene, 20 g of isoprene, and 10.0 g of heterogeneous catalysts X1 to X4 were added to a 500 mL Parr reactor. The reactor was sealed, stirred, and reacted at 50 °C and autogenous pressure for 4 hours. After the reaction was complete, methanol was added to terminate the reaction. The reaction product was then distilled under reduced pressure at 2.7 kPa, and the fractions were collected. The results are shown in Table 1.

[0034] Example 9

[0035] Same as Example 5, except that the cyclization trimerization reaction temperature is 80°C.

[0036] The results are shown in Table 1.

[0037] Table 1

[0038] Dimer selectivity, % Selectivity of cyclic trimers, % Example 5 0 79.3 Example 6 0 73.6 Example 7 0 71.2 Example 8 0 68.7 Example 9 1.3 62.4

[0039] When this catalyst is used to catalyze the trimerization of isoprene cyclization, under certain conditions such as increased temperature, a small amount of dimerization byproducts will be present in the reaction products.

[0040] Byproducts such as dimerization should be minimized to facilitate subsequent product separation and purification.

Claims

1. An isoprene cyclization trimer catalyst, characterized in that, The catalyst consists of a titanium-containing material supported on graphene and alkyl aluminum chloride. The titanium-containing material accounts for 1-20% of the mass of graphene based on titanium, and the mass ratio of alkyl aluminum chloride to the titanium-containing material supported on graphene is 2-20:

1. The mass of the titanium-containing material supported on graphene refers to the total mass of the titanium-containing material and graphene. The graphene has fewer than 10 layers, a sheet size of 0.5-5 micrometers, and an ash content of less than 0.1%.

2. The catalyst according to claim 1, characterized in that, The titanium-containing material is 2-10% of the mass of graphene, calculated as titanium.

3. The catalyst according to claim 1, characterized in that, The alkyl aluminum chloride is sesquiethyl aluminum chloride and / or diethylaluminum chloride.

4. The catalyst according to claim 1, characterized in that, The alkyl aluminum chloride has a mass content of 50-95%.

5. The catalyst according to claim 1, characterized in that, The alkyl aluminum chloride has a mass content of 70-90%.

6. The isoprene cyclization trimer catalyst according to any one of claims 1-5, characterized in that, The preparation method includes the steps of mixing and reacting graphene, TiCl4 and light aromatic hydrocarbons and recovering the product, and mixing the product with alkyl aluminum chloride to obtain an isoprene cyclization trimer catalyst composed of titanium-containing material supported on graphene and alkyl aluminum chloride.

7. The catalyst according to claim 6, characterized in that, The process includes the following steps: under anhydrous and oxygen-free reaction conditions and nitrogen protection, graphene, TiCl4 and light aromatic hydrocarbons are mixed and stirred at 10-60℃ for 4-24 hours. The mixture is then separated, washed, dried, and mixed with alkyl aluminum chloride to obtain an isoprene cyclization trimer catalyst composed of titanium-containing materials supported on graphene and alkyl aluminum chloride.

8. The catalyst according to claim 6, characterized in that, The weight ratio of graphene, TiCl4, light aromatic hydrocarbons and alkyl aluminum chloride is 1:5-20:10-200:20-100.

9. The catalyst according to any one of claims 6-8, characterized in that, The light aromatic hydrocarbon is toluene.

10. A method for isoprene cyclization trimerization, characterized in that, Under cyclopolymerization conditions, isoprene is used as a raw material to carry out a cyclopolymerization reaction in contact with a catalyst. The catalyst consists of a titanium-containing substance supported on graphene and alkyl aluminum chloride. The titanium-containing substance accounts for 1-20% of the mass of graphene based on titanium, and the mass ratio of alkyl aluminum chloride to the titanium-containing substance supported on graphene is 2-20:

1. The mass of the titanium-containing substance supported on graphene refers to the total mass of the titanium-containing substance and graphene. The graphene has fewer than 10 layers, a sheet size of 0.5-5 micrometers, and an ash content of less than 0.1%. The cyclopolymerization reaction is carried out at 30-80°C.

11. The method according to claim 10, characterized in that, The cyclopolymerization reaction is carried out at 35-70°C.