Isoprene cyclization trimerization catalyst as well as preparation method and application thereof

Abstract

The invention discloses an isoprene cyclization trimerization catalyst which is characterized in that the catalyst is composed of a titanium-containing substance loaded on graphene and alkyl aluminum chloride, the titanium-containing substance accounts for 1-20% of the mass of the graphene in terms of titanium, and the mass ratio of the alkyl aluminum chloride to the titanium-containing substance loaded on the graphene is (2-20): 1. When the catalyst is used for catalyzing an isoprene cyclization trimerization reaction, no or few dimerization byproducts exist in reaction products.

Description

Technical Field

[0001] The present invention relates to a catalyst for synthesizing oligomers, a preparation method and application thereof, and more specifically to an isoprene cyclotrimerization catalyst, a preparation method thereof and an isoprene cyclotrimerization method thereof. Background Art

[0002] Isoprene is one of the main olefins produced in the petrochemical production process and an important organic chemical raw material with a wide range of application prospects. With the rapid development of science and technology, the continuous progress of olefin low molecular weight polymerization technology, such as dimerization and trimerization, has attracted increasing attention. Among them, the one with the widest application prospect and relatively high industrial value is the cyclization of isoprene to form trimethylcyclododecatriene.

[0003] Nanocarbon materials are the star materials in the material world, and graphene is one of the hot research materials in recent years. It has adjustable size, high hydrothermal stability, and large specific surface area, and has broad application prospects in catalysis, separation, biology, and nanomaterials. Summary of the invention

[0004] The inventors of the present invention have found that when a heterogeneous catalyst composed of a titanium compound supported on graphene and an alkylaluminum chloride is used to catalyze the cyclotrimerization reaction of isoprene, surprisingly, no dimerization byproduct is produced in the reaction product under certain conditions. Based on this, the present invention is formed.

[0005] The purpose of the present invention is to provide an isoprene cyclotrimerization catalyst and a preparation method thereof which are different from those in the prior art, and to provide an isoprene cyclotrimerization method.

[0006] In order to achieve the above-mentioned object, the first aspect of the present invention provides an isoprene cyclotrimerization catalyst, characterized in that the catalyst is composed of a titanium-containing substance supported on graphene and an alkylaluminum chloride, the mass content of the titanium-containing substance in terms of titanium is 1-20%, and the mass ratio of the alkylaluminum chloride to the titanium-containing substance supported on graphene is 2-20:1.

[0007] In order to achieve the above object, the second aspect of the present invention provides a method for preparing an isoprene cyclotrimerization catalyst, characterized in that it comprises the following steps: the method comprises: 4 The product is mixed with light aromatic hydrocarbons for reaction and recovered, and then mixed with alkyl aluminum chloride to obtain an isoprene cyclotrimerization catalyst consisting of a titanium-containing substance supported on graphene and alkyl aluminum chloride.

[0008] In order to achieve the above-mentioned purpose, the third aspect of the present invention provides a method for cyclotrimerization of isoprene, characterized in that, under cyclopolymerization reaction conditions, isoprene is used as a raw material and is contacted with a catalyst for cyclopolymerization reaction, the catalyst is composed of a titanium-containing substance supported on graphene and an alkylaluminum chloride, the mass content of the titanium-containing substance in terms of titanium is 1-20%, and the mass ratio of the alkylaluminum chloride to the titanium-containing substance supported on the graphene is 2-20:1.

[0009] The isoprene cyclotrimerization reaction provided by the present invention has no dimerization by-product in the reaction product under certain conditions, which is more conducive to the production of trimerization products. DETAILED DESCRIPTION

[0010] An isoprene cyclotrimerization catalyst, characterized in that the catalyst consists of a titanium-containing substance supported on graphene and an alkylaluminum chloride, wherein the titanium-containing substance accounts for 1-20% of the mass of the graphene in terms of titanium, and the mass ratio of the alkylaluminum chloride to the titanium-containing substance supported on the graphene is 2-20:1, wherein the mass of the titanium-containing substance supported on the graphene refers to the total mass of the titanium-containing substance and the graphene.

[0011] In the catalyst of the present invention, preferably, the titanium-containing substance accounts for 2-10% of the mass of graphene in terms of titanium.

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

[0013] The present invention also provides a method for preparing an isoprene cyclotrimerization catalyst, comprising the following specific steps: reacting graphene, TiCl 4 and light aromatic hydrocarbons, reacted at 10-60° C. with stirring for 4-24 hours, separated, washed, and dried to obtain a titanium-containing substance supported on graphene, and then mixed with alkylaluminum chloride to obtain an isoprene cyclotrimerization catalyst composed of a titanium-containing substance supported on graphene and alkylaluminum chloride. Specifically, the graphene, TiCl 4 The weight ratio of the light aromatic hydrocarbon to the alkylaluminum chloride can be 1:5-20:10-200:20-100.

[0014] Graphene is a nano-carbon material with adjustable size, high hydrothermal stability, large specific surface area, and is used in catalysis, separation, biology, nanomaterials, etc. In the present invention, the graphene is preferably obtained by supercritical exfoliation, with less than 10 layers, a sheet size of 0.5-5 microns, and an ash content of less than 0.1%.

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

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

[0017] The present invention further provides a cyclotrimerization method of isoprene, characterized in that, under cyclopolymerization reaction conditions, isoprene is used as a raw material and is contacted with a catalyst to carry out a cyclopolymerization reaction; wherein the catalyst is composed of a titanium-containing substance supported on graphene and an alkylaluminum chloride, the titanium-containing substance is 1-20% of the mass of the graphene in terms of titanium, and the mass ratio of the alkylaluminum chloride to the titanium-containing substance supported on the graphene is 2-20:1, wherein the mass of the titanium-containing substance supported on the graphene refers to the total mass of the titanium-containing substance and the graphene.

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

[0019] The present invention is further described below by way of examples, but the present invention is not limited thereto.

[0020] In the examples, the composition of the products after the reaction was analyzed by gas chromatography, and the selectivity of the cyclic trimerization product was calculated according to the following formula.

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

[0022] Examples 1-4 are used to illustrate the catalyst and preparation method thereof provided by the present invention.

[0023] Example 1

[0024] Under the protection of nitrogen in anhydrous and oxygen-free reaction conditions, 1.5 g of graphene and an appropriate amount of TiCl 4 The mixture was stirred and mixed with 200 g of toluene, reacted with stirring at 40° C. for 12 h, filtered, washed with hexane three times, dried, and mixed with 150 g of sesquiethylaluminum chloride to obtain a heterogeneous catalyst X1.

[0025] The titanium content in the catalyst X1 is 5.3%, the mass content of the titanium-containing substance supported on the graphene is 18%, and the mass content of sesquiethylaluminum chloride is 82%.

[0026] Example 2

[0027] Under the protection of nitrogen in anhydrous and oxygen-free reaction conditions, 4.0 g of graphene and an appropriate amount of TiCl 4The mixture was mixed with 100 g of toluene, stirred and reacted at 50° C. for 20 h, filtered, washed three times with hexane, dried, and mixed with 100 g of sesquiethylaluminum chloride to obtain a heterogeneous catalyst X2.

[0028] The titanium content in the catalyst X2 is 1.2%, the mass content of the titanium-containing substance supported on the graphene is 13%, and the mass content of sesquiethylaluminum chloride is 87%.

[0029] Embodiment 3, 4

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

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

[0032] Embodiment 5-8

[0033] Under nitrogen protection, 150 mL toluene, 20 g isoprene, and 10.0 g heterogeneous catalysts X1 to X4 were added to a 500 mL Parr reactor, which was sealed and stirred at a constant temperature of 50°C and autogenous pressure for 4 hours. After the reaction was completed, methanol was added to the resulting liquid to terminate the reaction, and the reaction product was distilled under reduced pressure at a pressure of 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 cyclotrimerization reaction temperature is 80°C.

[0036] The results are shown in Table 1.

[0037] Table 1

[0038] Dimerization product selectivity, % Cyclotrimer product selectivity, % 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 the catalyst is used to catalyze the cyclotrimerization reaction of isoprene, under certain conditions such as increased temperature, a small amount of dimerization by-product will be produced in the reaction product.

[0040] By-products such as dimerization should be avoided as much as possible to facilitate the separation and purification of subsequent products.

Claims

1. An isoprene cyclotrimerization catalyst, characterized in that: The catalyst consists of a titanium-containing substance supported on graphene and alkylaluminum chloride, wherein the titanium-containing substance accounts for 1-20% of the mass of the graphene in terms of titanium, and the mass ratio of the alkylaluminum chloride to the titanium-containing substance supported on the graphene is 2-20:1, wherein the mass of the titanium-containing substance supported on the graphene refers to the total mass of the titanium-containing substance and the graphene.

2. The catalyst according to claim 1, characterized in that The titanium-containing substance accounts for 2-10% of the mass of the graphene in terms of titanium.

3. The catalyst according to claim 1, characterized in that The alkylaluminum chloride is sesquiethylaluminum chloride and / or diethylaluminum monochloride.

4. The catalyst according to claim 1, characterized in that The mass content of the alkylaluminum chloride is 50-95%, preferably 70-90%.

5. The method for preparing the isoprene cyclotrimerization catalyst according to any one of claims 1 to 4, characterized in that: The method comprises the steps of mixing graphene, TiCl4 and light aromatic hydrocarbons for reaction and recovering products, and mixing the products with alkylaluminum chloride to obtain an isoprene cyclotrimerization catalyst consisting of a titanium-containing substance supported on graphene and alkylaluminum chloride.

6. The preparation method according to claim 5, characterized in that: The method comprises the following steps: mixing graphene, TiCl4 and light aromatic hydrocarbons under anhydrous and oxygen-free reaction conditions and under nitrogen protection, stirring and reacting at 10-60° C. for 4-24 hours, separating, washing, drying, and mixing with alkyl aluminum chloride to obtain an isoprene cyclotrimerization catalyst composed of a titanium-containing substance supported on graphene and alkyl aluminum chloride.

7. The preparation method according to claim 6, characterized in that: The weight ratio of graphene, TiCl4, light aromatic hydrocarbon and alkylaluminum chloride is 1:5-20:10-200:20-100.

8. The preparation method according to claim 6 or 7, characterized in that: The light aromatic hydrocarbon is toluene.

9. The preparation method according to claim 6 or 7, characterized in that: The alkylaluminum chloride is sesquiethylaluminum chloride and / or diethylaluminum monochloride.

10. A method for cyclotrimerization of isoprene, characterized in that: Under cyclopolymerization conditions, isoprene is used as a raw material and is contacted with a catalyst for cyclopolymerization. The catalyst consists of a titanium-containing substance supported on graphene and an alkylaluminum chloride. The titanium-containing substance accounts for 1-20% of the mass of the graphene in terms of titanium, and the mass ratio of the alkylaluminum chloride to the titanium-containing substance supported on the graphene is 2-20:1, wherein the mass of the titanium-containing substance supported on the graphene refers to the total mass of the titanium-containing substance and the graphene.

11. The method according to claim 10, characterized in that The cyclopolymerization reaction conditions are 30-80°C, Preferred temperature is 35-70°C.