A method for cyclotrimerization of butadiene, a catalyst used in the method and a method for preparing the catalyst

Abstract

A method for cyclotrimerization of butadiene, characterized in that the catalyst is composed of acid-modified carbon nanotubes and titanium-containing substances supported thereon, and the titanium content is 1-20% by mass of the catalyst. The cyclotrimerization of butadiene is catalyzed by the catalyst, and the mass ratio of the cis-trans isomers of 1,5,9-cyclododecatriene in the obtained product is greater than 1.

Description

Technical Field

[0001] This invention relates to a butadiene cyclization trimer catalyst, its preparation method, and its catalytic method for butadiene cyclization trimerization. Background Technology

[0002] Butadiene is one of the three major olefins produced during petrochemical production and is an important organic chemical raw material with a wide range of applications. It is mainly used in the production of polybutadiene rubber, such as styrene-butadiene rubber, cis-butadiene rubber, nitrile rubber, and chloroprene rubber. With the rapid development of science and technology and the continuous advancement of low-molecular-weight polymerization technology for olefins, such as dimerization and trimerization, it has received increasing attention. Among these, the most promising and industrially valuable is the trimerization and cyclization of butadiene to form 1,5,9-cyclododecanetriene (CDT).

[0003] CDT is an important intermediate in organic and fine chemicals with special applications. It can be used to synthesize saturated or unsaturated dicarboxylic acids and their derivatives. It is also a raw material for polyesters, polyamides, plasticizers, flame retardants, macrocyclic organic compounds, and certain macrocyclic musk. The product of selective hydrogenation via an amine-rhodium catalyst can be used to produce nylon 12, cyclododecanoic acid, n-dodecane, bromododecane, cyclic dodecane-1 olefins, and cyclic dodecane-2 olefins, etc., and has a wide range of industrial applications.

[0004] CDT has four stereoisomers: trans, trans, trans-1,5,9-cyclododecanetriene (i.e., (E,E,E)-1,5,9-CDT), cis, trans, trans-1,5,9-cyclododecanetriene (i.e., (Z,E,E)-1,5,9-CDT), cis, cis, trans-1,5,9-cyclododecanetriene (i.e., (Z,Z,E)-1,5,9-CDT), and cis, cis, cis-1,5,9-cyclododecanetriene (i.e., (Z,Z,Z)-1,5,9-CDT).

[0005] When using titanium-based Ziegler-type catalysts, the main product of butadiene cyclization trimerization is (Z,E,E)-1,5,9-CDT, while isomers of the (E,E,E)-1,5,9-CDT structure are few, and (Z,Z,E)-1,5,9-CDT is almost not generated. With the development of fine chemicals, the demand for various stereoisomers of CDT has increased. Obviously, existing titanium-based homogeneous catalysts cannot produce more (E,E,E)-1,5,9-CDT.

[0006] Furthermore, homogeneous systems suffer from problems such as the need for quenching and removal of the catalyst by adding polar substances like water or alcohol after the reaction, leading to the introduction of new impurities while removing existing ones, making the catalyst unrecyclable and generating solid waste. To address these issues, heterogeneous catalysts are a better choice. Carbon nanomaterials are star materials in the materials science field, with carbon nanotubes being one of the hottest research topics in recent years. They possess adjustable wall thickness, high hydrothermal stability, and a large specific surface area, showing broad application prospects in catalysis, separation, biology, and nanomaterials. Carbon nanomaterials can be compounded with active components to form heterogeneous catalysts, which hold promise for applications in diene cyclization trimerization reactions. Summary of the Invention

[0007] The inventors of this invention discovered that a heterogeneous catalyst prepared by modifying carbon nanotubes (CNTs) and supporting titanium compounds, combined with alkyl aluminum chloride as a co-catalyst, unexpectedly produced a reaction product (E,E,E)-1,5,9-CDT / (Z,E,E)-1,5,9-CDT, i.e., the mass ratio of the anti-cis product to 1,5,9-CDT, which is greater than 1. Based on this discovery, this invention was formed.

[0008] The purpose of this invention is to provide a butadiene cyclotrimerization catalyst, preparation method and catalytic butadiene cyclotrimerization reaction that are different from the prior art.

[0009] To achieve the above objectives, the first aspect of the present invention provides a butadiene cyclization trimer catalyst, characterized in that it is composed of carbon nanotubes and titanium-containing materials supported thereon, wherein the titanium content is 2-40% by mass of the catalyst, preferably 5-20%.

[0010] To achieve the above objectives, a second aspect of the present invention provides a method for preparing a butadiene cyclization trimer catalyst, characterized by comprising the following steps: a method for preparing a butadiene cyclization trimer catalyst, characterized by comprising the following steps: firstly, modifying carbon nanotubes by acid treatment to obtain modified carbon nanotubes; then, mixing and reacting the modified carbon nanotubes, TiCl4, and light aromatic hydrocarbons to obtain a butadiene cyclization trimer catalyst composed of modified carbon nanotubes and titanium supported thereon.

[0011] The method for preparing the butadiene cyclization trimer catalyst includes the following specific steps: First, multi-walled carbon nanotubes are refluxed and stirred with an acid of concentration ≤10 mol / L at 60-120℃ for 1-24 h. After filtration and drying, acid-modified multi-walled carbon nanotubes are obtained, wherein the weight ratio of acid to multi-walled carbon nanotubes is 5-50:1. Then, under anhydrous and oxygen-free reaction conditions and nitrogen protection, the modified multi-walled carbon nanotubes, TiCl4, and light aromatic hydrocarbons are mixed and stirred at 30-60℃ for 4-48 h. After separation, washing, and drying, the butadiene cyclization trimer catalyst composed of modified multi-walled carbon nanotubes and titanium supported thereon is obtained. The weight ratio of multi-walled carbon nanotubes, TiCl4, and light aromatic hydrocarbons is 1:5-20:20-100.

[0012] Carbon nanotubes, as nanomaterials, have become a hot research topic in recent years. They possess adjustable wall thickness, high hydrothermal stability, and a large specific surface area, making them promising candidates for applications in catalysis, separation, biology, and nanomaterials. In this invention, the carbon nanotubes are preferably multi-walled carbon nanotubes with a diameter of 3-50 nm, a length of 0.5-500 μm, and an ash content of less than 10%.

[0013] In the acid treatment modification, the preferred acid is nitric acid, and the weight ratio of carbon nanotubes to nitric acid solution is 1:10-30.

[0014] In the aforementioned modifying reagent, the general formula of the modifying reagent is R″R′N-(CH2)n-Si-A′A″A″′, wherein R′ and R″ are both H, or one of R′ and R″ is H and the other is a C1-C4 alkyl group, and A′, A″, and A″′ are all methoxy or all ethoxy, or when any one of A′, A″, and A″′ is methyl or ethyl, the other two are all methoxy, all ethoxy, or methoxy and ethoxy respectively, and n is 1, 2, 3, or 4; preferably, R′ and R″ are both H.

[0015] More preferably, the modifying agent is 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldiethoxysilane, or N-methyl-3-aminopropyltrimethoxysilane.

[0016] The light aromatic hydrocarbon can be selected from benzene, toluene, ethylbenzene, xylene, etc., with toluene being the preferred light aromatic hydrocarbon.

[0017] The weight ratio of TiCl4 to modified carbon nanotubes is 10:0.1-2.

[0018] The present invention also provides a butadiene cyclization trimer catalyst obtained by the above preparation method.

[0019] To achieve the above objectives, a third aspect of the present invention further provides a method for butadiene cyclization trimerization, characterized in that the method uses 1,3-butadiene as a raw material and, in the presence of the catalyst of the present invention or the catalyst obtained by the preparation method of the present invention and alkyl aluminum chloride as a co-catalyst, a cyclization reaction occurs at 30-90°C.

[0020] Preferably, the alkyl aluminum chloride is sesquiethyl aluminum chloride or diethylaluminum chloride, and more preferably diethylaluminum chloride.

[0021] Preferably, the mass ratio of the co-catalyst to the heterogeneous catalyst is 2-20:1, more preferably 5-15:1.

[0022] The cyclization trimerization method provided by this invention involves modifying CNT carbon nanotubes and then loading them with titanium-containing materials to prepare a heterogeneous catalyst. Alkyl aluminum chloride is used as a co-catalyst, and the mass ratio of the anti-cis product (E,E,E)-1,5,9-CDT / (Z,E,E)-1,5,9-CDT, i.e. 1,5,9-CDT, in the reaction product is greater than 1.

[0023] In addition, after the butadiene cyclization trimerization reaction is completed, the catalyst of the present invention can be reused after filtration or centrifugation under anhydrous and oxygen-free operating conditions. This overcomes the drawbacks of the existing homogeneous system and can be recycled after simple filtration or centrifugation, thus reducing the generation of waste. Detailed Implementation

[0024] The present invention will be further illustrated by the following examples, but these examples are not intended to limit the invention.

[0025] Examples 1-4 illustrate the heterogeneous catalyst and its preparation method provided by the present invention.

[0026] Example 1

[0027] a. Under stirring conditions, 30g of multi-walled carbon nanotubes (purchased from Chengdu Organic Research Institute Co., Ltd., with a diameter of 5-20nm, a length of 2-50μm, and an ash content of less than 5%, the same below) were mixed with 600g of 10mol / L nitric acid solution and reacted at 120℃ under reflux for 6h. After filtration, the mixture was washed with deionized water until neutral and dried at 120℃ to obtain acid-modified multi-walled carbon nanotubes.

[0028] b. Mix 25g of pretreated multi-walled carbon nanotubes, 20g of 3-aminopropyltrimethoxysilane H2N(CH2)3Si(OCH3)3 and 80g of toluene, stir and react at 60℃ for 12h, filter out the solid, and dry at 120℃ to obtain modified multi-walled carbon nanotubes.

[0029] c. Under anhydrous and oxygen-free reaction conditions and nitrogen protection, 28g of modified multi-walled carbon nanotubes, 20g of TiCl4 and 200g of toluene were mixed and stirred at 40°C for 24h. After filtration, the mixture was washed three times with hexane and dried to obtain the heterogeneous catalyst HeS1, in which the titanium content was 9.3%.

[0030] Example 2

[0031] a. Same as step a in Example 1.

[0032] b. Mix 25g of pretreated multi-walled carbon nanotubes, 25g of 3-aminopropyltriethoxysilane H2N(CH2)3Si(OC2H5)3 and 100g of toluene, stir and react at 70℃ for 6h, filter out the solid, and dry at 120℃ to obtain modified multi-walled carbon nanotubes.

[0033] c. Under anhydrous and oxygen-free reaction conditions and nitrogen protection, 28g of modified multi-walled carbon nanotubes, 12g of TiCl4 and 100g of toluene were mixed and stirred at 40°C for 20h. After filtration, the mixture was washed three times with hexane and dried to obtain the heterogeneous catalyst HeS2, in which the titanium content was 5.1%.

[0034] Example 3

[0035] a. Same as step a in Example 1.

[0036] b. Mix 20g of pretreated multi-walled carbon nanotubes, 25g of 3-aminopropylmethyldiethoxysilane H2N(CH2)3Si(CH2)(OC2H5)2 and 60g of toluene, stir and react at 80℃ for 6h, filter out the solid, and dry at 120℃ to obtain modified multi-walled carbon nanotubes.

[0037] c. Under anhydrous and oxygen-free reaction conditions and nitrogen protection, 24g of modified multi-walled carbon nanotubes, 30g of TiCl4 and 150g of toluene were mixed and stirred at 50°C for 8 hours. After filtration, the mixture was washed three times with hexane and dried to obtain the heterogeneous catalyst HeS3, in which the titanium content was 7.0%.

[0038] Example 4

[0039] a. Same as step a in Example 1.

[0040] b. Mix 15g of pretreated multi-walled carbon nanotubes, 30g of N-methyl-3-aminopropyltrimethoxysilane CH3NH(CH2)3Si(OCH3)3 and 90g of toluene, stir and react at 90℃ for 3h, filter out the solid, and dry at 120℃ to obtain modified multi-walled carbon nanotubes.

[0041] c. Under anhydrous and oxygen-free reaction conditions and nitrogen protection, 18g of modified multi-walled carbon nanotubes, 10g of TiCl4 and 100g of toluene were mixed and stirred at 60°C for 6 hours. After filtration, the mixture was washed three times with hexane and dried to obtain the heterogeneous catalyst HeC4, in which the titanium content was 6.3%.

[0042] Examples 5-8 illustrate the butadiene cyclization trimerization method provided by the present invention and the effect of reusing the catalyst.

[0043] Example 5

[0044] The 1LParr reactor was purged with nitrogen three times. Under nitrogen protection, 400 mL of toluene, 12 g of sesquiethylaluminum chloride, and 1.0 g of heterogeneous catalyst HeS1 were added. Stirring was started, and 1,3-butadiene was continuously introduced. The reaction was maintained at 50 °C and 0.1 MPa for 4 hours. After the reaction, the mixture was filtered under nitrogen protection. The resulting solid was designated Re-HeS1 and stored under nitrogen protection. The resulting liquid was treated with methanol to terminate the reaction. The reaction product was distilled under reduced pressure at 2.7 kPa. The fraction collected at 110 °C was (E,E,E)-1,5,9-CDT (cis) and the fraction collected at 116 °C was (Z,E,E)-1,5,9-CDT (trans). The mass ratio of 1,5,9-CDT to the trans-cis product was calculated to be 1.6.

[0045] Re-HeS1 was filtered under nitrogen protection, washed three times with hexane, and dried. Then, following the cyclization trimerization method described above, Re-HeS1 was used instead of HeS1 for the cyclization trimerization reaction of 1,3-butadiene. The mass ratio of the trans-cis product to the 1,5,9-CDT was 1.7.

[0046] Example 6

[0047] Same as Example 5, except that HeS2 is used instead of HeS1.

[0048] The mass ratio of the anti-cis product to 1,5,9-CDT is 1.8.

[0049] Re-HeS2 was filtered under nitrogen protection, washed three times with hexane, and dried. Then, following the cyclization trimerization method described above, Re-HeS2 was used instead of HeS2 for the cyclization trimerization reaction of 1,3-butadiene. The mass ratio of the anti-cis product to the 1,5,9-CDT was 2.0.

[0050] Example 7

[0051] Same as Example 5, except that HeS3 is used instead of HeS1.

[0052] The mass ratio of the anti-cis product of 1,5,9-CDT is 1.5.

[0053] Re-HeS3 was filtered under nitrogen protection, washed three times with hexane, and dried. Then, following the cyclization trimerization method described above, Re-HeS3 was used instead of HeS3 for the cyclization trimerization reaction of 1,3-butadiene. The mass ratio of the trans-cis product to the 1,5,9-CDT was 1.6.

[0054] Example 8

[0055] Same as Example 5, except that HeS4 is used instead of HeS1.

[0056] The mass ratio of the anti-cis product to 1,5,9-CDT is 1.4.

[0057] Re-HeS4 was filtered under nitrogen protection, washed three times with hexane, and dried. Then, following the cyclization trimerization method described above, Re-HeS4 was used instead of HeS4 for the cyclization trimerization reaction of 1,3-butadiene. The mass ratio of the trans-cis product to the 1,5,9-CDT was 1.5.

[0058] Example 9

[0059] This embodiment illustrates the butadiene cyclization trimerization method provided by the present invention.

[0060] Same as Example 5, except that the mass ratio of the co-catalyst and the heterogeneous catalyst is changed to 20:1.

[0061] The mass ratio of the anti-cis product of 1,5,9-CDT is 1.3.

[0062] Example 10

[0063] This embodiment illustrates the butadiene cyclization trimerization method provided by the present invention.

[0064] Same as Example 5, except that the co-catalyst is replaced with diethylaluminum chloride.

[0065] The mass ratio of the anti-cis product of 1,5,9-CDT is 2.4.

[0066] Example 11

[0067] This embodiment illustrates the butadiene cyclization trimerization method provided by the present invention.

[0068] Same as Example 5, except that the cyclization trimerization reaction temperature is changed to 80°C.

[0069] The mass ratio of the anti-cis product of 1,5,9-CDT is 1.9.

Claims

1. A method for butadiene cyclization trimerization, characterized in that, This method uses 1,3-butadiene as raw material and carries out a cyclization reaction under cyclization reaction conditions and in the presence of a catalyst and a co-catalyst; wherein, the catalyst is composed of acid-treated and silanized modified carbon nanotubes and titanium supported thereon, and the co-catalyst is alkyl aluminum chloride; and the catalyst is prepared by a method including the following steps: (1) reacting multi-walled carbon nanotubes with an acid of concentration ≤10mol / L at 60-120℃ under reflux stirring for 1-24h, filtering and drying to obtain acid-modified carbon nanotubes, wherein the weight ratio of acid to multi-walled carbon nanotubes is 5-50:1; (2) reacting acid-modified carbon nanotubes with an acid of concentration ≤10mol / L under reflux stirring for 1-24h, filtering and drying to obtain acid-modified carbon nanotubes, wherein the weight ratio of acid to multi-walled carbon nanotubes is 5-50:1; The carbon nanotubes were mixed with a silanizing agent and light aromatic hydrocarbons and stirred at 50-90℃ for 2-12 hours. After filtration and drying, silanized modified carbon nanotubes were obtained. (3) Under anhydrous and oxygen-free reaction conditions and nitrogen protection, silanized modified carbon nanotubes, TiCl4 and light aromatic hydrocarbons were mixed and stirred at 30-60℃ for 4-48 hours. After separation, washing and drying, butadiene cyclization trimer composed of modified carbon nanotubes and titanium supported thereon was obtained. The weight ratio of the silanized modified carbon nanotubes, TiCl4 and light aromatic hydrocarbons was 1:5-20:20-100. The general formula of the silanizing agent in step (2) is R. ′′ R ′ N-(CH2)n-Si-A ′ A ′′ A ′′′ The R ′ and the R ′′ Simultaneously H or the aforementioned R ′ and the R ′′ One of them is H and the other is a C1-C4 alkyl group, wherein A ′ A ′′ A ′′′ All are methoxy or all are ethoxy, or, when said A ′ A ′′ A ′′′ When any one of them is methyl or ethyl, the other two are either methoxy, either are either ethoxy, or either are methoxy or ethoxy respectively, and n is 1, 2, 3 or 4.

2. The method according to claim 1, characterized in that, The catalyst contains 2-40% titanium by mass.

3. The method according to claim 2, characterized in that, The catalyst contains 5-20% titanium by mass.

4. The method according to claim 1, characterized in that, The alkyl aluminum chloride is sesquiethyl aluminum chloride or diethylaluminum chloride.

5. The method according to claim 1, characterized in that, The mass ratio of the co-catalyst to the catalyst is 2-20:

1.

6. The method according to claim 1, characterized in that, The cyclopolymerization reaction conditions are 30-90℃.

7. A butadiene cyclization trimer catalyst, characterized in that, The catalyst consists of modified carbon nanotubes and titanium-containing materials supported thereon, with a titanium content of 2-40% by mass. The modification treatment is acid treatment and silanization treatment. The catalyst is prepared by a method including the following steps: (1) reacting multi-walled carbon nanotubes with an acid of concentration ≤10mol / L at 60-120℃ with stirring under reflux for 1-24h, filtering and drying to obtain acid-modified carbon nanotubes, wherein the weight ratio of acid to multi-walled carbon nanotubes is 5-50:1; (2) mixing the acid-modified carbon nanotubes with a silanizing agent and light aromatic hydrocarbons at 50- Stirred at 90℃ for 2-12h, filtered and dried to obtain silanized modified carbon nanotubes; (3) Under anhydrous and oxygen-free reaction conditions and nitrogen protection, silanized modified carbon nanotubes, TiCl4 and light aromatic hydrocarbons were mixed and stirred at 30-60℃ for 4-48h, separated, washed and dried to obtain butadiene cyclization trimer catalyst composed of modified carbon nanotubes and titanium supported thereon, wherein the weight ratio of silanized modified carbon nanotubes, TiCl4 and light aromatic hydrocarbons is 1:5-20:20-100; The general formula of the silanizing agent in step (2) is R ′′ R ′ N-(CH2)n-Si-A ′ A ′′ A ′′′ The R ′ and the R ′′ Simultaneously H or the aforementioned R ′ and the R ′′ One of them is H and the other is a C1-C4 alkyl group, wherein A ′ A ′′ A ′′′ All are methoxy or all are ethoxy, or, when said A ′ A ′′ A ′′′ When any one of them is methyl or ethyl, the other two are either methoxy, either are either ethoxy, or either are methoxy or ethoxy respectively, and n is 1, 2, 3 or 4.

8. The catalyst according to claim 7, characterized in that, The titanium content is 5-20% by mass.

9. A method for preparing a butadiene cyclization trimer catalyst, characterized in that, The method includes the following steps: (1) reacting multi-walled carbon nanotubes with an acid of concentration ≤10mol / L at 60-120℃ for 1-24h under reflux and stirring, filtering and drying to obtain acid-modified carbon nanotubes, wherein the weight ratio of acid to multi-walled carbon nanotubes is 5-50:1; (2) mixing acid-modified carbon nanotubes with silanizing reagent and light aromatic hydrocarbons, stirring and reacting at 50-90℃ for 2-12h, filtering and drying to obtain silanized modified carbon nanotubes; (3) Under anhydrous and oxygen-free reaction conditions and nitrogen protection, silanized modified carbon nanotubes, TiCl4, and light aromatic hydrocarbons are mixed and stirred at 30-60℃ for 4-48 hours. After separation, washing, and drying, a butadiene cyclization trimer catalyst composed of modified carbon nanotubes and titanium supported thereon is obtained. The weight ratio of the silanized modified carbon nanotubes, TiCl4, and light aromatic hydrocarbons is 1:5-20:20-100. The general formula of the silanizing agent in step (2) is R. ′′ R ′ N-(CH2)n-Si-A ′ A ′′ A ′′′ The R ′ and the R ′′ Simultaneously H or the aforementioned R ′ and the R ′′ One of them is H and the other is a C1-C4 alkyl group, wherein A ′ A ′′ A ′′′ All are methoxy or all are ethoxy, or, when said A ′ A ′′ A ′′′ When any one of them is methyl or ethyl, the other two are either methoxy, either are either ethoxy, or either are methoxy or ethoxy respectively, and n is 1, 2, 3 or 4.

10. The method according to claim 9, characterized in that, The acid mentioned in step (1) is nitric acid, and the weight ratio of multi-walled carbon nanotubes to nitric acid is 1:10-30.

11. The method according to claim 9, characterized in that, The silanizing agent is selected from one or more of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldiethoxysilane, and N-methyl-3-aminopropyltrimethoxysilane.

12. The method according to claim 9, characterized in that, Step (3) The weight ratio of silanized modified carbon nanotubes to TiCl4 is 1:10-15.

13. The method according to claim 9, characterized in that, The light aromatic hydrocarbon is toluene.