Polyether polymerization catalyst

Abstract

The invention relates to the technical field of chemical catalysis, in particular to a polyether polymerization catalyst which comprises the following components: double metal cyanide (DMC) of which the average particle size is 20-50nm, a cocatalyst of which the addition amount is 3-5% of the total mass of the catalyst, a Lewis acid-alkali pair catalyst of which the addition amount is 3-5% of the total mass of the catalyst, and a dispersing aid of which the addition amount is 1-2% of the total mass of the catalyst, the preparation method comprises the following steps: preparing a granular catalyst suitable for an industrial scale through a spray drying molding technology, improving the catalytic efficiency by 20% or more and reducing side reactions by 30% or more under the condition of 60-80 DEG C, and the generated polyether has narrow molecular weight distribution (PDilt, PDIt, PDIt, PDIt, PDIt, PDIt, PDIt, PDIt, PDIt, PDIt, PDIt, PDIt, PDIt, PDIt, PDIt and PDIt); 1.2) and a low degree of unsaturation (lt; the quality of the product is obviously improved, and the product is suitable for high-end application of polyurethane, lubricating oil and green chemicals.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of chemical catalysis, in particular to a polyether polymerization catalyst. BACKGROUND

[0002] Polyether is widely used in the production of polyurethane foam, lubricating oil, paint, adhesive and surfactant in modern industry. The synthesis of polyether usually adopts the ring-opening polymerization of epoxide (such as ethylene oxide and propylene oxide), and the catalyst is the core of the reaction;

[0003] In the prior art, most catalyst systems require high-temperature reaction (such as ≥100℃), which has the problems of high energy consumption, many side reactions (such as crosslinking by-products) and high unsaturation of products. Low-temperature catalysis (such as 60–80℃) is considered to be the development direction of polyether synthesis field, but the current low-temperature catalysts have the problems of low catalytic efficiency, insufficient stability and poor reaction selectivity, which cannot meet the industrialization needs. Therefore, it is necessary to develop a polyether catalyst which is efficient, environmentally friendly and suitable for low-temperature reaction, so as to improve the product quality and reduce the production cost. SUMMARY

[0004] (I) Technical problems solved

[0005] In view of the deficiencies of the prior art, the present application provides a composite catalyst for polyether synthesis and a preparation method thereof, which has high catalytic activity, high selectivity and low by-product generation rate under the condition of 60–80℃.

[0006] (II) Technical solutions

[0007] To achieve the above-mentioned purpose, the present application provides the following technical solutions: a polyether polymerization catalyst, which comprises the following components:

[0008] (1) double metal cyanide (DMC), with an average particle size of 20–50nm;

[0009] (2) a cocatalyst selected from triethanolamine, with an addition amount of 3%–5% of the total mass of the catalyst;

[0010] (3) a Lewis acid-base pair catalyst composed of aluminum chloride and pyridine in a molar ratio of 1:1.2;

[0011] (4) a dispersing aid, which is graphene oxide, with an addition amount of 1%–2% of the total mass of the catalyst.

[0012] Further, in the preparation process of the double metal cyanide, a complexing agent cyclohexanone is added, with a mass fraction of 0.5%–1% of the total amount of the reaction solution.

[0013] Further, the improvement of the present application is that the catalyst is prepared by spray drying technology, and the particle size is 50-100 μm.

[0014] Further, the improvement of the present application is that the particle size distribution span of the double metal cyanide (DMC) is less than 1.5.

[0015] A method for preparing the catalyst of claim 1, comprising the following steps:

[0016] (1) preparing a double metal cyanide catalyst;

[0017] (2) adding a co-catalyst and a Lewis acid-base pair catalyst;

[0018] (3) adding a dispersion aid and uniformly mixing;

[0019] (4) preparing a granular catalyst by spray drying technology.

[0020] Further, the improvement of the present application is that in the step (3) of adding a dispersion aid and uniformly mixing, a high-speed shearing homogenizer is used for mixing, and the mixing time is 30-60 minutes.

[0021] A method for synthesizing a polyether, using the catalyst of any one of claims 1-4 to catalyze the ring-opening polymerization reaction of an epoxide monomer at a temperature range of 60-80℃.

[0022] Further, the improvement of the present application is that the epoxide monomer is a mixture of propylene oxide and ethylene oxide, and the molar ratio of the two is 1:(0.2-0.5). Using the mixture of epoxide monomers in this ratio, combined with the catalyst of any one of claims 1-4, a polyether with specific properties and structure can be synthesized to meet the application requirements in different fields.

[0023] (III) Beneficial effects

[0024] Compared with the prior art, the present application provides a polyether polymerization catalyst, which has the following beneficial effects:

[0025] 1) A granular catalyst suitable for industrial scale is prepared by spray drying molding technology;

[0026] 2) The catalytic efficiency is improved by more than 20% at a temperature of 60-80℃;

[0027] 3) The side reaction is reduced by more than 30%, and the generated polyether has a narrow molecular weight distribution (PDI <1.2) and a low unsaturation degree (<0.02 mol / kg);

[0028] 4) The product quality is significantly improved, and is suitable for high-end applications of polyurethane, lubricating oil and green chemicals. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0030] A polyether polymerization catalyst according to the present application comprises the following components:

[0031] (1) Double metal cyanide (DMC), with an average particle size of 20-50 nm, which is one of the core active components of the catalyst. The average particle size is strictly selected and accurately controlled in the range of 20-50 nm. In this particle size range, the double metal cyanide has a large specific surface area and suitable surface activity, can fully contact with the reactants, effectively reduce the activation energy of the reaction, significantly improve the rate and selectivity of the polyether polymerization reaction, and ensure that the reaction proceeds efficiently in the expected direction;

[0032] (2) A promoter selected from triethanolamine, with an addition amount of 3%-5% of the total mass of the catalyst. Triethanolamine is selected as the promoter based on its unique chemical structure and chemical properties. The triethanolamine molecule contains multiple active functional groups, which can interact with double metal cyanide and other reactants, further optimize the active center structure of the catalyst, and enhance the adsorption and activation capacity of the catalyst to the reactants. The addition amount is strictly limited to 3%-5% of the total mass of the catalyst. Within this range, triethanolamine can fully play its catalytic role, while avoiding the increase in complexity of the catalyst system due to excessive addition, or failing to achieve the desired catalytic effect due to insufficient addition;

[0033] (3) Lewis acid-base pair catalyst, composed of aluminum chloride and pyridine in a molar ratio of 1:1.2. Aluminum chloride and pyridine are combined in a precise molar ratio of 1:1.2. Aluminum chloride, as a typical Lewis acid, has strong electron accepting ability; pyridine, as a Lewis base, has electron donating ability. The combination of the two in this specific ratio can form a unique acid-base synergistic catalyst system, creating a special reaction environment in the polyether polymerization reaction, promoting the polarization and activation of reactant molecules, thereby accelerating the reaction, improving the efficiency of the reaction and the quality of the product;

[0034] (4) Dispersion aid, graphene oxide, added amount 1% - 2% of the total mass of the catalyst, graphene oxide is used as a dispersion aid, which takes advantage of the excellent dispersion performance and unique two-dimensional structure of graphene oxide. Graphene oxide has a large specific surface area and abundant oxygen-containing functional groups, which can form a stable dispersion network in the catalyst system, effectively prevent the agglomeration and sedimentation between the components of the catalyst, and ensure the uniform distribution of the catalyst in the reaction system. The added amount is 1% to 2% of the total mass of the catalyst, within this range, graphene oxide can achieve the best dispersion effect, improve the stability and catalytic activity of the catalyst.

[0035] In this embodiment, a complexing agent cyclohexanone is added during the preparation of the double metal cyanide, with a mass fraction of 0.5% - 1% of the total amount of the reaction solution. Cyclohexanone can complex with metal ions during the synthesis of double metal cyanide, forming a stable complex structure. This complex structure can regulate the crystal growth process of double metal cyanide, control its crystal structure and particle size distribution, and thus optimize the catalytic performance of double metal cyanide. The mass fraction of cyclohexanone is strictly controlled within 0.5% to 1% of the total amount of the reaction solution, within this range, cyclohexanone can fully exert its complexing effect, while avoiding the introduction of impurities or adverse effects on the balance of the reaction system due to excessive addition.

[0036] In this embodiment, the catalyst is prepared by spray drying technology, with a particle size of 50 - 100 μm. Spray drying technology is an advanced particle preparation method, which can quickly atomize the catalyst solution into tiny droplets, and then rapidly evaporate the water under the action of hot gas flow, so that the droplets are instantly dried to form solid particles. By precisely controlling various parameters in the spray drying process, such as spray pressure, hot gas temperature, flow rate, etc., catalyst particles with uniform particle size within the range of 50 to 100 microns can be prepared. Catalyst particles with this specific particle size have good flowability and dispersibility, which is convenient for storage, transportation and use in industrial production, and also helps to improve the efficiency of catalytic reactions by facilitating the contact between catalyst and reactants.

[0037] In this embodiment, the particle size distribution span of the double metal cyanide (DMC) is less than 1.5. Narrow particle size distribution helps to further improve the activity and selectivity of the catalyst in the polyether polymerization reaction, making the reaction more stable and controllable.

[0038] A method for preparing the catalyst of claim 1, comprising the following steps:

[0039] (1) Preparation of double metal cyanide catalyst, according to the specific chemical formula and strict reaction conditions, carefully prepare the synthesis of double metal cyanide catalyst raw materials. In the reaction process, the proportion of various reactants, reaction temperature, reaction time and stirring speed and other key parameters are accurately controlled to ensure that the double metal cyanide can be synthesized in the expected way. At the same time, according to the requirements of claim 2, 0.5% to 1% of the total amount of the reaction solution of complexing agent cyclohexanone is accurately added to the reaction system, and the structure and performance of the double metal cyanide are optimized by the complexing effect of cyclohexanone. After the reaction is completed, after proper separation, washing and drying and other post-processing steps, the double metal cyanide catalyst with ideal catalytic performance is obtained;

[0040] (2) Add promoter and Lewis acid-base pair catalyst to the catalyst, accurately weigh the promoter triethanolamine and the Lewis acid-base pair catalyst (aluminum chloride and pyridine are composed according to the molar ratio of 1:1.2) in the prepared double metal cyanide catalyst according to the proportion specified in claim 1. Slowly add them to the double metal cyanide catalyst system, and use appropriate stirring methods such as mechanical stirring or magnetic stirring to ensure that the promoter and the Lewis acid-base pair catalyst can be uniformly dispersed in the double metal cyanide catalyst, realizing the full contact and synergistic effect between the components;

[0041] (3) Add dispersion aid and mix evenly, accurately add dispersion aid graphene oxide to the above-mentioned mixed system, and the addition amount is 1% to 2% of the total mass of the catalyst. In order to make the graphene oxide fully dispersed in the catalyst system, strong stirring, ultrasonic dispersion or ball milling method is used to destroy the agglomeration structure of the graphene oxide, so that it is uniformly distributed in the whole catalyst system. Through sufficient mixing, stable interaction between each component is formed, and the stability and catalytic activity of the catalyst are improved;

[0042] (4) Prepare granular catalyst by using spray drying technology, and deliver the mixed catalyst solution to the spray drying equipment. In the spray drying process, the key parameters such as spray pressure, hot gas temperature and flow rate are strictly controlled, so that the catalyst solution forms small droplets. These droplets rapidly evaporate water under the action of hot gas flow, forming granular catalyst with particle size of 50 to 100 microns. The prepared granular catalyst has good fluidity and dispersibility, which is convenient for subsequent industrial application.

[0043] In this embodiment, in step (3), a high-speed shearing homogenizer is used for mixing when the dispersion aid is added and mixed evenly, and the mixing time is 30-60 minutes. The high-speed shearing homogenizer can generate strong shear force, so that the dispersion aid is more uniformly dispersed in the catalyst system, further improving the dispersibility and stability of the catalyst.

[0044] A method for synthesizing polyether, using the catalyst of any one of claims 1-4 to catalyze the ring-opening polymerization of epoxide monomers at a temperature range of 60-80℃.

[0045] In this embodiment, the epoxide monomers are a mixture of propylene oxide and ethylene oxide with a molar ratio of 1:(0.2-0.5). Using this ratio of mixed epoxide monomers, combined with the catalyst of any one of claims 1-4, polyether with specific properties and structures can be synthesized to meet the application requirements of different fields.

[0046] The present application designs a composite catalyst based on double metal cyanide (DMC) and optimizes its activity and stability through nanodispersion technology.

[0047] 1) Introducing an organic amine cocatalyst to enhance reaction activity and reduce side reactions;

[0048] 2) Combining Lewis acid-base pair catalytic system to further improve the efficiency of epoxide ring-opening polymerization;

[0049] 3) Preparing granular catalysts suitable for industrial scale through spray drying molding technology.

[0050] 4) Catalytic efficiency is increased by more than 20% at 60-80℃;

[0051] 5) Side reactions are reduced by more than 30%, and the generated polyether has a narrow molecular weight distribution (PDI <1.2) and low unsaturation (<0.02 mol / kg);

[0052] 6) The product quality is significantly improved, and is suitable for high-end applications of polyurethane, lubricating oil and green chemicals.

[0053] 1. Catalyst composition:

[0054] (1) Main catalyst: double metal cyanide (DMC);

[0055] The composite crystal formed by selecting metal zinc (Zn) and cobalt (Co) has the chemical formula Zn3[Co(CN)6]2·xH2O (where x is the water content).

[0056] By adding complexing agents (such as cyclohexanone) to control the crystal morphology, the average particle size can reach 20-50 nm, improving the surface area and activity of the catalyst.

[0057] (2) Cocatalyst: organic amine compound;

[0058] Triethanolamine (C6H 15NO3) as a co-catalyst, with an addition amount of 3% - 5% of the total mass of the catalyst. Triethanolamine, due to its strong nucleophilicity, can effectively reduce the reaction energy barrier of epoxide and enhance the ring-opening polymerization activity.

[0059] (3) Lewis acid-base pair catalyst;

[0060] The Lewis acid is aluminum trichloride (AlCl3), and the Lewis base is pyridine (C5H5N); they are compounded in a molar ratio of 1:1.2 to form an acid-base pair catalyst, which synergistically activates the epoxide monomer and improves the catalytic efficiency.

[0061] (4) Dispersion aid;

[0062] Nano graphene oxide (GO) is used as a dispersion aid, with an addition amount of 1% - 2% of the total mass, to improve the uniformity and stability of the catalyst.

[0063] 2. Catalyst preparation method:

[0064] (1) Preparation of double metal cyanide catalyst (DMC):

[0065] Mix ZnCl2 and K3[Co(CN)6] solutions in stoichiometric ratio, stir at room temperature to generate a precipitate;

[0066] Add 0.5% - 1% of cyclohexanone complexing agent and continue to react for 6 hours to improve the crystal morphology;

[0067] Wash the precipitate with deionized water, vacuum filter, and freeze-dry to obtain DMC powder (particle size 20 - 50 nm).

[0068] (2) Mixed and compounded catalyst:

[0069] Mix DMC powder with triethanolamine (co-catalyst) in a mass ratio of 5:3;

[0070] Add Lewis acid-base pair catalyst of aluminum trichloride and pyridine;

[0071] Add graphene oxide dispersion aid, stir uniformly, and stand for 12 hours.

[0072] (3) Catalyst shaping:

[0073] Prepare the mixture into granular catalyst by spray drying technology, with a particle size of 50

[0074] - 100 μm, suitable for industrial scale application.

[0075] 3. Industrial application scenarios:

[0076] (1) High-performance polyurethane industry;

[0077] The polyether produced by the catalyst has low unsaturation and narrow molecular weight distribution, and is suitable for the production of high-end polyurethane foams and elastomers.

[0078] (2) Lubricating oil manufacturing;

[0079] The low unsaturation polyether can significantly improve the viscosity index and oxidation resistance of the lubricating oil.

[0080] (3) Green chemical market;

[0081] The environmental protection characteristics and low temperature reaction conditions of the catalyst make it suitable for green chemical production, such as non-toxic detergents and cosmetics.

[0082] The present application realizes innovation in catalyst composition, preparation method and application range, meets the needs of industrial production, and conforms to the development trend of low temperature, green and high efficiency of chemical industry.

[0083] In the description in this document, it should be noted that the relationship terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between the entities or operations. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or equipment.

[0084] Although embodiments of the present application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present application.

Claims

1. A polyether polymerization catalyst, characterized in that: The catalyst comprises the following components: (1) Double metal cyanide (DMC), with an average particle size of 20–50 nm; (2) Co-catalyst: triethanolamine is selected and the addition amount is 3%–5% of the total mass of the catalyst; (3) a Lewis acid-base catalyst consisting of aluminum chloride and pyridine in a molar ratio of 1:1.2; (4) Dispersing aid, graphene oxide, added in an amount of 1%–2% of the total mass of the catalyst.

2. A polyether polymerization catalyst according to claim 1, characterized in that: During the preparation of the double metal cyanide, a complexing agent, cyclohexanone, is added with a mass fraction of 0.5%-1% of the total amount of the reaction solution.

3. A polyether polymerization catalyst according to claim 2, characterized in that: The catalyst is prepared by spray drying technology, and the particle size is 50-100 μm.

4. A polyether polymerization catalyst according to claim 1, characterized in that The particle size distribution span of the double metal cyanide (DMC) is less than 1.

5.

5. A method for preparing the catalyst according to claim 1, characterized in that: The following steps are involved: (1) preparing a double metal cyanide catalyst; (2) adding a co-catalyst and a Lewis acid-base catalyst; (3) Add dispersing aid and mix evenly; (4) The granular catalyst was prepared using spray drying technology.

6. A method for preparing a catalyst according to claim 5, characterized in that: When adding the dispersing aid and uniformly mixing in step (3), a high-speed shear homogenizer is used for mixing, and the mixing time is 30-60 minutes.

7. A method for synthesizing polyether, characterized in that: The catalyst according to any one of claims 1 to 4 is used to catalyze the ring-opening polymerization reaction of epoxide monomers within a temperature range of 60 to 80°C.

8. The method for synthesizing polyether according to claim 7, wherein: The epoxide monomer is a mixture of propylene oxide and ethylene oxide, and the molar ratio of the two is 1:(0.2-0.5). Using the mixed epoxide monomers in this ratio, combined with the catalyst according to any one of claims 1-4, polyethers with specific properties and structures can be synthesized to meet application requirements in different fields.