CN118546279A - New decanoic acid rare earth catalyst for polymerization and preparation method and application thereof - Google Patents

Abstract

The invention relates to the technical field of catalysts, and in particular to a neodecanoic acid rare earth catalyst for polymerization, a preparation method and an application thereof. The neodecanoic acid rare earth catalyst comprises the following components: neodymium neodecanoate, a halogen-containing compound, an alcohol compound, a conjugated diene and an auxiliary agent, wherein the auxiliary agent comprises a mixture of triphenyl(methyl)-tetrakis(pentafluorobenzene)borate and phenyl-dimethylamino-tetraphenylborate, and the molar ratio of the two is 2-4:1. The polybutadiene product prepared by the rare earth catalyst has high cis-structure content, molecular weight and yield, and has a narrow molecular weight distribution, and the raw materials are easily available and the cost is low.

Description

A neodecanoic acid rare earth catalyst for polymerization and its preparation method and application

Technical Field

The invention relates to the technical field of catalysts, and in particular to a neodecanoic acid rare earth catalyst for polymerization and a preparation method and application thereof.

Background Art

Butadiene rubber is the abbreviation of cis-1,4-polybutadiene rubber, and its molecular formula is (C ₄ H ₆ ) _n . Butadiene rubber is a synthetic rubber with a regular structure formed by the polymerization of 1,3-butadiene, and its cis structure content is more than 95%. Butadiene rubber is particularly suitable for manufacturing automobile tires and cold-resistant products, and can also be used to manufacture cushioning materials and various rubber shoes, rubber cloths, tapes and sponge rubbers.

The polymerization reaction of 1,3-butadiene as a monomer to prepare butadiene rubber is a highly stereospecific reaction that can provide a variety of polybutadiene with different microstructures and affect the basic properties of rubber. The stereoselectivity of 1,3-butadiene is mainly controlled by adjusting the polymerization parameters (i.e., reaction temperature, solvent used, and catalyst system). Butadiene rubber can be divided into nickel-based, cobalt-based, titanium-based, and rare earth (neodymium-based) butadiene rubber according to the different catalysts.

Rare earth catalysts are generally multi-component systems with rare earth compounds as the main catalyst. When the main catalyst is a rare earth compound containing halogen, alkyl aluminum is usually added to form a catalyst with catalytic activity, which is a binary system. When the main catalyst is a rare earth compound without halogen, in addition to adding alkyl aluminum, a Lewis acid that can provide halogen must also be added to form a catalyst with catalytic activity, which is a ternary system. In addition, in order to improve the activity of the catalyst, improve the catalyst phase, and adjust the molecular weight and microstructure of the polymerization, it is usually necessary to add some regulators, such as dienes, carboxylic acids, and aromatic hydrocarbons.

However, the current rare earth catalytic system catalysts have the problems of cumbersome preparation process, complex composition and high cost. The yield of polybutadiene rubber products is low, and most rare earth catalytic systems have not yet achieved a 1,4-cis selectivity higher than 98%, which limits their practical application.

For example, Chinese patent application CN113929802A discloses a neodecanoic acid rare earth catalyst and its preparation method and application, the rare earth catalyst comprising: a, neodymium phosphate compound; b, conjugated diene; c, alkyl aluminum or alkyl aluminum hydride, or a mixture of the two; d, halogen-containing compound; wherein the molar ratio of each component is a:b:c:d=1:(2-50):(5-40):(1-20). The polybutadiene rubber product prepared by the rare earth catalyst provided by the invention has a cis structure content of less than 98% and a molecular weight distribution Mw/Mn of more than 2. Therefore, the cis structure content needs to be further increased and the molecular weight distribution needs to be further narrowed.

Chinese patent CN117264103B discloses a rare earth catalyst containing neodymium neodecanoate and a method for preparing polybutadiene rubber based on the catalyst. The rare earth catalyst containing neodymium neodecanoate is made of neodymium neodecanoate, alcohol compounds, methylaluminoxane, conjugated dienes and ionic liquids. The rare earth catalyst provided by the invention has the advantages of high activity and high cis selectivity, and can prepare high-quality polybutadiene rubber products with the characteristics of ultra-high cis, high molecular weight, narrow molecular weight distribution, etc., and the product has a high yield. However, ionic liquids are used in the catalyst, the preparation process is complicated, and the cost is relatively high.

Therefore, it is very necessary to develop a neodecanoic acid rare earth catalyst and a preparation method and application thereof that can solve the above-mentioned technical problems.

Summary of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art and provide a neodecanoic acid rare earth catalyst and a preparation method and application thereof. The polybutadiene product prepared by the neodecanoic acid rare earth catalyst of the present invention has a high cis structure content, molecular weight and yield, and a narrow molecular weight distribution. The raw materials are easily available and the cost is low.

The present invention is achieved through the following technical solutions:

A rare earth neodecanoate catalyst for polymerization comprises the following components: neodymium neodecanoate, a halogen-containing compound, an alcohol compound, a conjugated diene and an auxiliary agent, wherein the auxiliary agent comprises a mixture of triphenyl(methyl)-tetrakis(pentafluorobenzene)borate and phenyl-dimethylamino-tetraphenylborate, with a molar ratio of 2-4:1.

Preferably, the halogen-containing compound comprises an alkylaluminum halide.

More preferably, the alkylaluminum halide includes at least one of diethylaluminum monochloride and diisobutylaluminum trichloride.

More preferably, the alkyl aluminum halide is a mixture of diethylaluminum monochloride and diisobutylaluminum trichloride, with a molar ratio of 1-3:1.

Preferably, the alcohol compound includes at least one of isopropanol and cyclohexanol.

More preferably, the alcohol compound is a mixture of isopropanol and cyclohexanol, with a molar ratio of 3-5:1.

Preferably, the conjugated diene is isoprene and/or piperylene.

Preferably, the molar ratio of the neodymium element, the halogen-containing compound, the alcohol compound, the conjugated diene, and the additive in the neodymium neodecanoate is 1:1-20:5-10:20-80:1-5.

More preferably, the molar ratio of the neodymium element, the halogen-containing compound, the alcohol compound, the conjugated diene, and the additive in the neodymium neodecanoate is 1:5-15:6-8:30-70:2-4.

Preferably, the method for preparing neodymium neodecanoate comprises the following steps:

(1) dissolving neodymium oxide with hydrochloric acid, controlling the pH to 4.5-5.0, and removing impurities to obtain a neodymium chloride NdCl3 solution;

(2) allowing the NdCl3 solution of step (1) to stand, filtering and precipitating to obtain a clarified NdCl3 solution;

(3) mixing neodecanoic acid and n-hexane, adding a 5 mol/L sodium hydroxide solution, and performing a saponification reaction at 60-65° C. for 30-35 minutes to obtain a reaction solution;

(4) adding the clarified NdCl3 solution to the reaction solution of step (3), mixing and reacting for more than 20 minutes, and standing to separate the phases;

(5) The upper layer of the finished product in step (4) is further filtered to remove impurities.

More preferably, the amount of neodymium oxide is 23-24 parts by weight, neodecanoic acid is 170-178 parts by weight, n-hexane is 185-195 parts by weight, and sodium hydroxide solution is 50-55 parts by weight.

The present invention also relates to a method for preparing the above-mentioned neodecanoic acid rare earth catalyst, comprising the following steps:

1) Under an inert atmosphere, dissolving neodymium neodecanoate, an alcohol compound, an auxiliary agent and a conjugated diene in an organic solvent to obtain a mixed solution A;

2) Add a halogen-containing compound to the mixed solution A to obtain a mixed solution B, and age it for 15-30 minutes.

Preferably, the organic solvent in step 1) is an inert organic solvent.

More preferably, the inert organic solvent comprises saturated aliphatic hydrocarbons and/or alicyclic hydrocarbons.

More preferably, the inert organic solvent comprises C5-C10 straight-chain alkanes and/or C5-C10 cycloalkanes.

More preferably, the inert organic solvent comprises at least one of n-pentane, n-hexane, cyclohexane and n-heptane.

Preferably, the amount of the organic solvent in step 1) is: neodymium neodecanoate: organic solvent = 0.3-0.6 mol/L.

The present invention also relates to the use of the neodecanoic acid rare earth catalyst or the neodecanoic acid rare earth catalyst prepared by the above preparation method in the preparation of polybutadiene.

Preferably, the method for preparing polybutadiene is as follows:

Under an inert atmosphere, the neodecanoic acid rare earth catalyst and 1,3-butadiene monomer are mixed in a solvent, and a polymerization reaction is carried out at 40-70° C. to obtain the product.

More preferably, the solvent is cyclohexane.

More preferably, the molar ratio of neodymium neodecanoate to 1,3-butadiene monomer in the neodecanoate rare earth catalyst is 2×10 ^-5 -6×10 ^-5 :1.

More preferably, the usage ratio of the 1,3-butadiene monomer to the solvent is 1.5-2.5 mol/L.

More preferably, the polymerization reaction time is 1.5-2.5 h.

More preferably, the polymerization reaction is terminated using a terminator commonly used in the art, for example, at least one of ethanol, isopropanol, and 2,6-di-tert-butylhydroquinone methanol.

The beneficial effects of the present invention are:

The present invention optimizes the composition of the rare earth catalyst, and the halogen-containing compound, the alcohol compound and the auxiliary agent have a significant synergistic effect, which significantly improves the catalytic activity and selectivity of the catalyst. The prepared polybutadiene rubber has a higher cis structure content, a larger molecular weight and a narrower molecular weight distribution, and a high product yield.

The present invention further optimizes the composition of the auxiliary agent, triphenyl (methyl) -tetrakis (pentafluorobenzene) borate and phenyl - dimethylamino - tetraphenyl borate have a significant synergistic effect, further improves the catalytic activity and selectivity of the catalyst, and significantly improves the yield of the polybutadiene rubber product, the product molecular weight, the molecular weight distribution effect and the cis structure stereoselectivity.

DETAILED DESCRIPTION

The present invention will be further described below in conjunction with specific embodiments, and the advantages and features of the present invention will become clearer as the description proceeds. However, these embodiments are merely exemplary and do not constitute any limitation to the scope of the present invention. It should be understood by those skilled in the art that the details and forms of the technical solution of the present invention may be modified or replaced without departing from the spirit and scope of the present invention, but these modifications and replacements all fall within the scope of protection of the present invention.

Example 1

A neodecanoate rare earth catalyst comprises the following components: neodymium neodecanoate, a halogen-containing compound, an alcohol compound, a conjugated diene and an auxiliary agent, wherein the molar ratio of the neodymium element, the halogen-containing compound, the alcohol compound, the conjugated diene and the auxiliary agent in the neodymium neodecanoate is 1:1:5:20:1, and the auxiliary agent comprises a mixture of triphenyl(methyl)-tetrakis(pentafluorobenzene)borate and phenyl-dimethylamino-tetraphenylborate, and the molar ratio of the two is 2:1;

The halogen-containing compound is a mixture of diethylaluminum monochloride and diisobutylaluminum trichloride, with a molar ratio of 1:1;

The alcohol compound is a mixture of isopropanol and cyclohexanol, with a molar ratio of 3:1;

The conjugated diene is isoprene.

The preparation method of neodymium neodecanoate comprises the following steps:

(1) dissolving 23 parts by weight of neodymium oxide in hydrochloric acid, controlling the pH to 4.5, and removing impurities to obtain a neodymium chloride NdCl ₃ solution;

(2) allowing the NdCl ₃ solution of step (1) to stand, filtering and precipitating to obtain a clarified NdCl ₃ solution;

(3) 170 parts by weight of neodecanoic acid and 185 parts by weight of n-hexane were mixed, 50 parts by weight of a 5 mol/L sodium hydroxide solution was added, and a saponification reaction was carried out at 60° C. for 35 minutes to obtain a reaction solution;

(4) adding the clarified NdCl ₃ solution to the reaction solution of step (3), mixing and reacting for more than 20 minutes, and standing for phase separation;

(5) The upper layer of the finished product in step (4) is further filtered to remove impurities.

The preparation method of the rare earth catalyst comprises the following steps:

1) Under an inert atmosphere, dissolving neodymium neodecanoate, an alcohol compound, an auxiliary agent and a conjugated diene in n-pentane, neodymium neodecanoate:n-pentane=0.3 mol/L, to obtain a mixed solution A;

2) Add a halogen-containing compound to the mixed solution A to obtain a mixed solution B, and age it for 15 minutes.

Example 2

A neodecanoate rare earth catalyst comprises the following components: neodymium neodecanoate, a halogen-containing compound, an alcohol compound, a conjugated diene and an auxiliary agent, wherein the molar ratio of the neodymium element, the halogen-containing compound, the alcohol compound, the conjugated diene and the auxiliary agent in the neodymium neodecanoate is 1:20:10:80:5, and the auxiliary agent comprises a mixture of triphenyl(methyl)-tetrakis(pentafluorobenzene)borate and phenyl-dimethylamino-tetraphenylborate, and the molar ratio of the two is 4:1;

The halogen-containing compound is a mixture of diethylaluminum monochloride and diisobutylaluminum trichloride, with a molar ratio of 3:1;

The alcohol compound is a mixture of isopropanol and cyclohexanol, with a molar ratio of 5:1;

The conjugated diene is piperylene.

The preparation method of neodymium neodecanoate comprises the following steps:

(1) dissolving 24 parts by weight of neodymium oxide in hydrochloric acid, controlling the pH to 5.0, and removing impurities to obtain a neodymium chloride NdCl ₃ solution;

(2) allowing the NdCl ₃ solution of step (1) to stand, filtering and precipitating to obtain a clarified NdCl ₃ solution;

(3) 178 parts by weight of neodecanoic acid and 195 parts by weight of n-hexane were mixed, 55 parts by weight of a 5 mol/L sodium hydroxide solution was added, and a saponification reaction was carried out at 65° C. for 30 minutes to obtain a reaction solution;

(4) adding the clarified NdCl ₃ solution to the reaction solution of step (3), mixing and reacting for more than 20 minutes, and standing for phase separation;

(5) The upper layer of the finished product in step (4) is further filtered to remove impurities.

The preparation method of the rare earth catalyst comprises the following steps:

1) Under an inert atmosphere, dissolving neodymium neodecanoate, an alcohol compound, an auxiliary agent and a conjugated diene in n-heptane, neodymium neodecanoate: n-heptane = 0.6 mol/L, to obtain a mixed solution A;

2) Add a halogen-containing compound to the mixed solution A to obtain a mixed solution B, and age it for 30 minutes.

Example 3

A neodecanoate rare earth catalyst comprises the following components: neodymium neodecanoate, a halogen-containing compound, an alcohol compound, a conjugated diene and an auxiliary agent, wherein the molar ratio of the neodymium element, the halogen-containing compound, the alcohol compound, the conjugated diene and the auxiliary agent in the neodymium neodecanoate is 1:10:7:50:3, and the auxiliary agent comprises a mixture of triphenyl(methyl)-tetrakis(pentafluorobenzene)borate and phenyl-dimethylamino-tetraphenylborate, and the molar ratio of the two is 3:1;

The halogen-containing compound is a mixture of diethylaluminum monochloride and diisobutylaluminum trichloride, with a molar ratio of 2:1;

The alcohol compound is a mixture of isopropanol and cyclohexanol, with a molar ratio of 4:1;

The conjugated diene is isoprene.

The preparation method of neodymium neodecanoate comprises the following steps:

(1) dissolving 24 parts by weight of neodymium oxide in hydrochloric acid, controlling the pH to 4.5, and removing impurities to obtain a neodymium chloride NdCl ₃ solution;

(2) allowing the NdCl ₃ solution of step (1) to stand, filtering and precipitating to obtain a clarified NdCl ₃ solution;

(3) 175 parts by weight of neodecanoic acid and 190 parts by weight of n-hexane were mixed, 53 parts by weight of a 5 mol/L sodium hydroxide solution was added, and a saponification reaction was carried out at 65° C. for 35 minutes to obtain a reaction solution;

(4) adding the clarified NdCl ₃ solution to the reaction solution of step (3), mixing and reacting for more than 20 minutes, and standing for phase separation;

(5) The upper layer of the finished product in step (4) is further filtered to remove impurities.

The preparation method of the rare earth catalyst comprises the following steps:

1) Under an inert atmosphere, dissolving neodymium neodecanoate, an alcohol compound, an auxiliary agent and a conjugated diene in cyclohexane, neodymium neodecanoate: cyclohexane = 0.5 mol/L, to obtain a mixed solution A;

2) Add a halogen-containing compound to the mixed solution A to obtain a mixed solution B, and age it for 20 minutes.

Comparative Example 1

The only difference from Example 3 is the catalyst composition. The molar ratios of the components are as follows:

Comparative Example 1-1 Comparative Example 1-2 Comparative Examples 1-3 Neodymium neodecanoate 1 1 1 Conjugated dienes 50 50 50 Halogen compounds 0 15.38 11.76 Alcohol compounds 14 0 8.24 Additives 6 4.62 0

Comparative Example 2

The only difference from Example 3 is that the auxiliary agent composition is different, and is replaced by an equal molar amount of methylaluminoxane.

Comparative Example 3

The only difference from Example 3 is the auxiliary agent composition, in which triphenyl(methyl)-tetrakis(pentafluorophenyl)borate is replaced by an equimolar amount of phenyl-dimethylamino-tetraphenylborate.

Comparative Example 4

The only difference from Example 3 is the auxiliary agent composition, in which phenyl-dimethylamino-tetraphenylborate is replaced by an equimolar amount of triphenyl(methyl)-tetrakis(pentafluorophenyl)borate.

Application Examples

Preparation method of polybutadiene: Under nitrogen atmosphere, any neodecanoic acid rare earth catalyst of Examples 1-3 and Comparative Examples 1-4 and 1,3-butadiene monomer are mixed in cyclohexane, the molar ratio of neodymium neodecanoate to 1,3-butadiene monomer is 4×10 ^-5 :1, and the amount ratio of 1,3-butadiene monomer to cyclohexane is 2 mol/L. The polymerization reaction is carried out at 60° C. for 2 h, and an appropriate amount of ethanol is added to terminate the reaction. The product is obtained after drying.

Test Case

The yield, cis-structure content, molecular weight and molecular weight distribution of the polybutadiene prepared in the application example were measured. The results are shown in Table 1.

Table 1

From Comparative Examples 1-1 to 1-3, it can be seen that when only any two of the halogen-containing compound, the alcohol compound and the auxiliary agent are contained, the polybutadiene yield, the stereoselectivity of the cis structure, and the product molecular weight are significantly reduced, and the molecular weight distribution is significantly broadened. This shows that the halogen-containing compound, the alcohol compound and the auxiliary agent of the present invention have a significant synergistic effect, and can simultaneously improve the polybutadiene yield, the stereoselectivity of the cis structure, the product molecular weight and the molecular weight distribution.

From the comparison between Comparative Example 2 and Example 3, it can be seen that after the auxiliary agent of the present invention is replaced with methylaluminoxane, the product yield, stereoselectivity of the cis structure and the molecular weight are significantly reduced, especially the molecular weight distribution effect, which is reduced by 56.6%.

By comparing Comparative Examples 1-3, Comparative Example 3, Comparative Example 4 and Example 3, it can be seen that Comparative Examples 3 and Comparative Example 4 add an auxiliary agent on the basis of Comparative Examples 1-3, and the product yield, product molecular weight and molecular weight distribution effects are improved, but the stereoselectivity of the cis structure is less affected. Example 3 adds two auxiliary agents, and the stereoselectivity of the cis structure is significantly improved, and the molecular weight distribution effect, yield and molecular weight are further significantly improved, indicating that the two auxiliary agents have a significant synergistic effect.

The above detailed description is a specific description of one feasible embodiment of the present invention. The embodiment is not intended to limit the patent scope of the present invention. Any equivalent implementation or modification that does not deviate from the present invention should be included in the scope of the technical solution of the present invention.

Claims (16)

1. A rare earth neodecanoate catalyst for polymerization, characterized in that it comprises the following components: neodymium neodecanoate, a halogen-containing compound, an alcohol compound, a conjugated diene and an auxiliary agent, wherein the auxiliary agent comprises a mixture of triphenyl(methyl)-tetrakis(pentafluorobenzene)borate and phenyl-dimethylamino-tetraphenylborate, with a molar ratio of 2-4:1. 2. The neodecanoic acid rare earth catalyst according to claim 1, characterized in that the halogen-containing compound comprises an alkyl aluminum halide. 3. The neodecanoic acid rare earth catalyst according to claim 2, characterized in that the alkyl aluminum halide comprises at least one of diethylaluminum monochloride and diisobutylaluminum trichloride. 4. The neodecanoic acid rare earth catalyst according to claim 3, characterized in that the alkyl aluminum halide is a mixture of diethylaluminum monochloride and diisobutylaluminum trichloride, with a molar ratio of 1-3:1. 5. The neodecanoic acid rare earth catalyst according to claim 1, characterized in that the alcohol compound comprises at least one of isopropanol and cyclohexanol. 6. The neodecanoic acid rare earth catalyst according to claim 5, characterized in that the alcohol compound is a mixture of isopropanol and cyclohexanol, with a molar ratio of 3-5:1. 7. The neodecanoic acid rare earth catalyst according to claim 1, characterized in that the molar ratio of the neodymium element, the halogen-containing compound, the alcohol compound, the conjugated diene, and the auxiliary agent in the neodymium neodecanoate is 1:1-20:5-10:20-80:1-5. 8. The neodecanoic acid rare earth catalyst according to claim 7, characterized in that the molar ratio of the neodymium element, the halogen-containing compound, the alcohol compound, the conjugated diene, and the auxiliary agent in the neodymium neodecanoate is 1:5-15:6-8:30-70:2-4. 9. The method for preparing the neodecanoic acid rare earth catalyst according to any one of claims 1 to 8, characterized in that it comprises the following steps: (1) Under an inert atmosphere, dissolving neodymium neodecanoate, an alcohol compound, an auxiliary agent and a conjugated diene in an organic solvent to obtain a mixed solution A; (2) Add a halogen-containing compound to the mixed solution A to obtain a mixed solution B, and age the mixed solution for 15-30 minutes. 10. The preparation method according to claim 9, characterized in that the organic solvent in step (1) is an inert organic solvent. 11. The preparation method according to claim 10, characterized in that the inert organic solvent comprises saturated aliphatic hydrocarbons and/or alicyclic hydrocarbons. 12 . The preparation method according to claim 10 , wherein the inert organic solvent comprises C5-C10 straight-chain alkanes and/or C5-C10 cycloalkanes. 13. The preparation method according to claim 10, characterized in that the inert organic solvent comprises at least one of n-pentane, n-hexane, cyclohexane and n-heptane. 14. The preparation method according to claim 9, characterized in that the amount of the organic solvent used in step (1) is: neodymium neodecanoate: organic solvent = 0.3-0.6 mol/L. 15. Use of the neodecanoic acid rare earth catalyst according to any one of claims 1 to 8 or the neodecanoic acid rare earth catalyst prepared by the preparation method according to any one of claims 9 to 14 in the preparation of polybutadiene. 16. The use according to claim 15, characterized in that the method for preparing polybutadiene is as follows: Under an inert atmosphere, the neodecanoic acid rare earth catalyst and 1,3-butadiene monomer are mixed in a solvent, and a polymerization reaction is carried out at 40-70° C. to obtain the product.