Cyclic polymerization method, catalyst and preparation method of catalyst

Abstract

The invention relates to a 1, 3-pentadiene cyclization polymerization method, which is characterized in that 1, 3-pentadiene is used as a raw material to carry out cyclization polymerization reaction in the presence of a catalyst, and the catalyst is composed of titanium on carbon dots CDs and alkyl aluminum chloride. According to the method disclosed by the invention, the selectivity of the product cyclic tripolymer 3, 7, 11-trimethyl-1, 5, 9-cyclododecatriene is improved.

Description

Technical Field

[0001] The present invention relates to a cyclopolymerization method, a catalyst and a method for preparing the catalyst. The present invention further relates to a method for cyclopolymerization of 1,3-pentadiene catalyzed by a titanium-based catalyst supported on carbon dots (CDs), a titanium-based catalyst and a method for preparing the titanium-based catalyst. Background Art

[0002] 1,3-Pentadiene is an important organic chemical raw material and intermediate, and is one of the olefins produced in the petrochemical production process. It is widely used. 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.

[0003] The existing 1,3-pentadiene cyclopolymerization catalytic system is mainly a homogeneous system, and the product after trimerization is mainly trimethylcyclododecatriene. Specifically, the product cyclic trimer is mainly 3,7,11-trimethyl-1,5,9-cyclododecatriene, and its selectivity still has much room for improvement. Summary of the invention

[0004] The inventors have found that a catalyst composed of a titanium compound and alkylaluminum chloride supported by carbon dots CDs can effectively catalyze the cyclopolymerization reaction of 1,3-pentadiene and improve the selectivity of its product, the cyclic trimer 3,7,11-trimethyl-1,5,9-cyclododecatriene. Based on this, the present invention is formed.

[0005] Therefore, one of the objects of the present invention is to provide a 1,3-pentadiene cyclopolymerization method with improved selectivity of cyclopolymerization products, a second object is to provide a catalyst for the 1,3-pentadiene cyclopolymerization method that is different from the prior art, and a third object is to provide a method for preparing the catalyst.

[0006] In order to achieve one of the purposes of the present invention, the first aspect of the present invention provides a cyclopolymerization method, characterized in that the method carries out a cyclopolymerization reaction with 1,3-pentadiene as a raw material in the presence of a catalyst, and the catalyst is composed of titanium and alkylaluminum chloride supported on carbon dots CDs, and the titanium content is 0.1-8% based on the mass of the catalyst.

[0007] In order to achieve the second purpose of the present invention, the second aspect of the present invention provides a titanium-based catalyst, characterized in that the catalyst is composed of titanium and alkylaluminum chloride supported on carbon dots CDs, and the titanium content is 0.1-8% based on the mass of the catalyst.

[0008] In order to achieve the third purpose of the present invention, the third aspect of the present invention provides a method for preparing the titanium-based catalyst described in the second aspect above, characterized in that the method includes mixing carbon dots CDs, TiCl4 and light aromatic hydrocarbons under anhydrous and oxygen-free reaction conditions and nitrogen protection, and then mixing them evenly with alkyl aluminum chloride. Optionally, the solid catalyst can be recovered by filtration, washing, and drying.

[0009] In the process of preparing the titanium-based catalyst by the method of the present invention, the obtained catalyst slurry can be used directly for the cyclopolymerization reaction of 1,3-pentadiene without filtering, washing and other steps, and no additional solvent is added, which greatly simplifies the preparation process steps of the catalyst, saves materials and energy consumption, and reduces costs. Moreover, surprisingly, the selectivity of the product cyclic trimer 3,7,11-trimethyl-1,5,9-cyclododecatriene is improved when the catalyst slurry is directly used for the cyclopolymerization reaction of 1,3-pentadiene. DETAILED DESCRIPTION

[0010] In 2004, the tiny carbon nanoparticles with a size of less than 10 nm found in the electrophoresis method for purifying single-layer carbon nanotubes were named carbon quantum dots CDs for the first time, which is a new type of small-sized carbon nanomaterial. The present invention uses it in the cyclopolymerization catalyst to improve the selectivity of the cyclic trimer 3,7,11-trimethyl-1,5,9-cyclododecatriene produced by the cyclopolymerization method of 1,3-pentadiene.

[0011] The cyclopolymerization method of the present invention is characterized in that the method uses 1,3-pentadiene as a raw material for cyclopolymerization reaction in the presence of a catalyst, wherein the catalyst is composed of titanium supported on carbon dots CDs and alkyl aluminum chloride, and the titanium content is 0.1-8% based on the mass of the catalyst. The alkyl aluminum chloride is sesquiethyl aluminum chloride and / or diethyl aluminum monochloride. The weight ratio of the titanium supported on the carbon dots CDs to the alkyl aluminum chloride is 1:5-40, preferably 1:10-25.

[0012] In the cyclopolymerization method of the present invention, the cyclopolymerization reaction of 1,3-pentadiene is optionally carried out in a reactor. Specifically, the air in the reactor is first replaced with nitrogen, and then the catalyst and 1,3-pentadiene are added to the reactor under nitrogen protection and stirring, and the reaction is carried out at 50-80°C and 0.1-1.0MPa, preferably 60-70°C and 0.2-0.6MPa for 1-12 hours. After the reaction is completed, it is stored under nitrogen protection, and optionally, methanol is added to the obtained liquid to terminate the reaction.

[0013] The present invention also provides a titanium-based catalyst, characterized in that the catalyst is composed of titanium and alkylaluminum chloride supported on carbon dots CDs, and the titanium content is 0.1-8% based on the mass of the catalyst. Preferably, the titanium content is 1-5%.

[0014] The present invention further provides a method for preparing a titanium-based catalyst, characterized in that the method comprises mixing carbon dots CDs, TiCl4 and light aromatic hydrocarbons under anhydrous and oxygen-free reaction conditions and nitrogen protection, and then uniformly mixing them with alkyl aluminum chloride.

[0015] In the preparation method, the average particle size of the primary particles of the carbon dots CDs is 5-10 nm, the carbon content is 50-80%, the balance is oxygen, and the molar ratio of surface CO to surface C=O is 1-5. The carbon dots CDs can be purchased commercially or made in-house. The present invention has no special limitation on the source of the carbon dots CDs, as long as the above requirements are met.

[0016] Preferably, in the preparation method, under anhydrous and oxygen-free reaction conditions and nitrogen protection, the carbon dots CDs are first mixed with light aromatic hydrocarbons and then mixed with TiCl4 and stirred at 30-60°C for 5-30h, and then alkyl aluminum chloride is added and mixed evenly.

[0017] In the preparation method, the weight ratio of the carbon dots CDs, TiCl4, light aromatic hydrocarbons, and alkyl aluminum chloride is 1:0.5-20:2-50:2-25; preferably, the weight ratio of the carbon dots CDs, TiCl4, light aromatic hydrocarbons, and alkyl aluminum chloride is 1:1-15:5-25:5-20.

[0018] In the preparation method, the preferred light aromatic hydrocarbons are selected from one or more of benzene, toluene, ethylbenzene and xylene, and the more preferred light aromatic hydrocarbon is toluene.

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

[0020] Examples 1-4 are used to illustrate the catalyst and preparation method thereof provided by the present invention.

[0021] Example 1

[0022] Under anhydrous and oxygen-free reaction conditions and under nitrogen protection, 6 g of carrier carbon dots CDs (Shanghai Enwang Technology Co., Ltd., the average particle size of the primary particles is 8 nm, the carbon content is 63.1%, the balance is oxygen, the molar ratio of surface CO to surface C=O is 1.8, the same below), an appropriate amount of TiCl4 and 180 g of toluene are mixed, stirred and reacted at 30°C for 24 hours, and then 100 g of sesquiethylaluminum chloride is added and stirred and reacted at 30°C for 4 hours to obtain a titanium-based catalyst, numbered FC1, in which the titanium content is 2.6%.

[0023] Example 2

[0024] Under anhydrous and oxygen-free reaction conditions and under nitrogen protection, 6 g of carbon dots CDs, an appropriate amount of TiCl4 and 200 g of toluene were mixed, stirred and reacted at 40°C for 18 h, and then 50 g of sesquiethylaluminum chloride was added and stirred and reacted at 40°C for 6 h to obtain a titanium-based catalyst, numbered FC2, in which the titanium content was 1.8%.

[0025] Example 3

[0026] Under anhydrous and oxygen-free reaction conditions and under nitrogen protection, 6 g of carbon dots CDs, an appropriate amount of TiCl4 and 250 g of toluene were mixed and stirred at 50°C for 10 h. Then 150 g of sesquiethylaluminum chloride was added and stirred at 30°C for 6 h to obtain a titanium-based catalyst, numbered FC3, in which the titanium content was 3.1%.

[0027] Example 4

[0028] Under anhydrous and oxygen-free reaction conditions and under nitrogen protection, 6 g of carbon dots CDs, an appropriate amount of TiCl4 and 150 g of toluene were mixed and stirred at 60°C for 5 h. Then 250 g of sesquiethylaluminum chloride was added and stirred at 60°C for 6 h to obtain a titanium-based catalyst, numbered FC4, in which the titanium content was 0.9%.

[0029] Example 5

[0030] This example illustrates the cyclopolymerization process of 1,3-pentadiene.

[0031] The cyclopolymerization of 1,3-pentadiene was carried out in a 500 mL Parr reactor.

[0032] First, the gas in the reaction kettle was replaced with nitrogen three times, and then 100 mL of the catalyst FC1 prepared in Example 1 was added to the kettle under nitrogen protection, stirring was turned on, 1,3-pentadiene was continuously added, the temperature was kept at 65° C., the pressure was kept at 0.2 MPa, and the reaction was carried out for 4 hours. After the reaction was completed, methanol was added to the obtained liquid and stored under nitrogen protection to terminate the reaction, and the reaction product was treated by distillation to obtain a fraction composition.

[0033] Selectivity of cyclic trimer 3,7,11-trimethyl-1,5,9-cyclododecatriene=(mass of CDT in the product / total mass of the product)×100%.

[0034] In this embodiment, the selectivity of the cyclic trimer 3,7,11-trimethyl-1,5,9-cyclododecatriene is 63%.

[0035] Embodiment 6-8

[0036] This example illustrates the cyclopolymerization process of 1,3-pentadiene.

[0037] The same as Example 5, except that catalysts FC2 to FC4 prepared in Examples 2 to 4 are used as catalysts.

[0038] The selectivities of the cyclic trimer 3,7,11-trimethyl-1,5,9-cyclododecatriene were 72%, 69% and 65% respectively.

[0039] Example 9

[0040] This example illustrates the cyclopolymerization process of 1,3-pentadiene.

[0041] Same as Example 5, except that the cyclopolymerization temperature is changed to 80°C.

[0042] The selectivity of the cyclic trimer 3,7,11-trimethyl-1,5,9-cyclododecatriene was 61%.

[0043] Comparative Example 1

[0044] The catalyst was prepared according to the method of Example 1, except that the same mass of activated carbon (Sinopharm Group, analytical grade, ash content <0.1%) was used to replace the carbon dots, numbered D1, in which the titanium content was 2.7%.

[0045] Comparative Example 2

[0046] The cyclopolymerization reaction of 1,3-pentadiene was carried out according to the method of Example 5, except that the catalyst was replaced by D1 of Comparative Example 1 instead of FC1.

[0047] The selectivity of the cyclic trimer 3,7,11-trimethyl-1,5,9-cyclododecatriene was 49%.

[0048] Comparative Example 3

[0049] The catalyst was prepared according to the method of Example 1, except that the carbon dots were replaced by white carbon black (Sinopharm Group, analytical grade, SiO2>99.9%) of the same mass, numbered D2, in which the titanium content was 2.3%.

[0050] Comparative Example 4

[0051] The cyclopolymerization reaction of 1,3-pentadiene was carried out according to the method of Example 5, except that the catalyst was replaced by D2 of Comparative Example 3 instead of FC1.

[0052] The selectivity of the cyclic trimer 3,7,11-trimethyl-1,5,9-cyclododecatriene was 33%.

Claims

1. A cyclopolymerization method, characterized in that: The method uses 1,3-pentadiene as a raw material for cyclopolymerization reaction under polymerization reaction conditions and in the presence of a catalyst. The catalyst is composed of alkyl aluminum chloride and titanium supported on carbon dots CDs. The titanium content is 0.1-8% based on the mass of the catalyst, and preferably the titanium content is 1-5%.

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

3. The method according to claim 1, characterized in that The weight ratio of the titanium supported on the carbon dots CDs to the alkylaluminum chloride is 1:5-40, and the preferred weight ratio is 1:10-25.

4. The method according to claim 1, characterized in that The polymerization reaction conditions are as follows: under nitrogen protection, the catalyst and 1,3-pentadiene are in contact at 50-80° C. and 0.1-1.0 MPa, preferably 60-70° C. and 0.2-0.6 MPa for 1-12 hours.

5. A titanium-based catalyst, characterized in that The catalyst consists of alkyl aluminum chloride and titanium supported on carbon dots CDs, and the content of titanium is 0.1-8% based on the mass of the catalyst.

6. The catalyst according to claim 5, characterized in that The titanium content is 1-5%.

7. The method for preparing the titanium-based catalyst according to claim 5, characterized in that: The method comprises the following steps: reacting carbon dots CDs, TiCl4 and light aromatic hydrocarbons under anhydrous and oxygen-free reaction conditions and under nitrogen protection, and then uniformly mixing with alkyl aluminum chloride to obtain the titanium-based catalyst.

8. The method according to claim 7, characterized in that The carbon dots CDs have an average primary particle size of 5-10 nm, a carbon content of 50-80%, the remainder being oxygen, and a molar ratio of surface CO to surface C=O of 1-5.

9. The method according to claim 7, characterized in that The carbon dots CDs are mixed with light aromatics and then with TiCl4 and reacted at 30-60°C with stirring for 5-30h, and then alkyl aluminum chloride is added and mixed evenly.

10. The method according to claim 7, characterized in that The weight ratio of the carbon dots CDs, TiCl4, light aromatic hydrocarbons and alkyl aluminum chloride is 1:0.5-20:2-50:2-25.

11. The method according to claim 10, characterized in that The weight ratio of the carbon dots CDs, TiCl4, light aromatic hydrocarbons and alkyl aluminum chloride is 1:1-15:5-25:5-20.

12. The method according to any one of claims 7, 10-11, characterized in that: The light aromatics are selected from one or more of benzene, toluene, ethylbenzene and xylene.

13. The method according to any one of claims 7, 10-11, characterized in that: The light aromatic hydrocarbon is toluene.