A rare earth metal-doped titanium catalyst, its preparation method and application
By doping titanium-based catalysts with rare earth metals, stable titanium-organic chelates and bimetallic active sites are formed, solving the problems of easy hydrolysis and poor stability of titanium-based catalysts, and realizing efficient polyester synthesis.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINESE TEXTILE ACAD
- Filing Date
- 2024-12-02
- Publication Date
- 2026-06-02
AI Technical Summary
Existing titanium-based catalysts are prone to hydrolysis, have poor stability, slow catalytic reaction rates, and numerous side reactions, resulting in complex and inefficient polyester synthesis processes.
A rare earth metal-doped titanium catalyst is prepared by forming a stable titanium-organic chelate with an organotitanate and a carboxylic acid, which then reacts with a rare earth metal precursor to form a bimetallic active site, thus simplifying the process.
It significantly improves catalytic activity, shortens polycondensation reaction time, yields high-viscosity copolyesters, and is easy to apply in industry.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of polyester catalysts, specifically, it relates to a rare earth metal-doped titanium catalyst, its preparation method, and its application. Background Technology
[0002] In recent years, the excessive use of large quantities of difficult-to-recycle polymer materials has caused problems such as white pollution, attracting widespread attention worldwide. Replacing non-degradable polymer materials with biodegradable ones is one effective measure to solve this problem. Biodegradable aliphatic-aromatic copolymers, such as polybutylene terephthalate (PBAT) and polybutylene terephthalate (PBST), have become hot research materials due to their excellent processing and biodegradability. Catalysts are a key factor in polyester synthesis. Currently, commonly used catalysts in polyester synthesis include antimony, titanium, germanium, and tin-based catalysts. Considering catalytic activity, stability, price, and environmental safety, titanium-based catalysts have become a research hotspot in polyester catalysts.
[0003] Widely used titanium-based catalysts mainly include inorganic titanates (such as potassium titanium oxalate, titanium chloride, etc.) and organic titanates (tetrabutyl titanate, tetraethyl titanate, etc.). However, these titanium-based catalysts are prone to hydrolysis, resulting in the loss of active sites, poor stability, slow catalytic reaction rates, and numerous side reactions. Therefore, modification of titanium-based catalysts is currently a common method. Acordis has developed a C94 solid polycondensation catalyst composed of titanium dioxide and silica, which has higher stability than titanate catalysts (US578952). Tsinghua University has disclosed a titanium compound-metal oxide-phosphorus compound-silicon compound composite catalyst system, which reduces the polycondensation reaction time and increases the viscosity of PBS polyester during the synthesis of biodegradable polybutylene succinate (PBS). However, the entire catalyst synthesis process is complex, involving multiple steps such as hydrolysis, calcination, compounding, reflux, and filtration, resulting in a lengthy process flow (ZL200910241743.7). In addition, the Beijing Research Institute of Chemical Industry of China Petroleum & Chemical Corporation disclosed a catalytic system for preparing biodegradable polyesters by a binary mixture of rare earth metal compounds and organotitanate esters. This system can significantly improve the polyester reaction rate and product molecular weight. However, since it uses a two-component mixture, it has not solved the problems of hydrolysis of titanium catalysts. Furthermore, it has problems such as complex preparation process of rare earth metal compounds, harsh conditions, and mixing with the reactants (CN1796434A).
[0004] Therefore, researching and developing titanium-based catalyst systems with simple processes, resistance to hydrolysis, high activity, and stability remains the key to the preparation of biodegradable polyesters.
[0005] In view of this, the present invention is proposed. Summary of the Invention
[0006] The technical problem to be solved by this invention is to overcome the shortcomings of the prior art and provide a rare earth metal-doped titanium catalyst, its preparation method, and its application. The rare earth metal-doped titanium catalyst of this invention is in a gel state, wherein the formed titanium organic chelate can inhibit catalyst hydrolysis and deactivation, and the formed bimetallic active sites can improve catalytic reaction activity, greatly shortening the polycondensation reaction time, improving polymerization efficiency, and obtaining a high-viscosity copolyester.
[0007] To solve the above-mentioned technical problems, the basic concept of the technical solution adopted by the present invention is as follows:
[0008] This invention provides a rare earth metal-doped titanium catalyst, the raw materials of which include the following components: organotitanate, rare earth metal precursor, carboxylic acid and alcohol solution; the rare earth metal-doped titanium catalyst is in a gel state, the organotitanate and carboxylic acid form a titanium-organic chelate, and the rare earth metal precursor and the titanium-organic chelate form a bimetallic active site.
[0009] The rare earth metal-doped titanium catalyst of the present invention is in a gel state, and the gel catalyst can form a uniform solution with the diol monomer, which is easy to apply in industry.
[0010] This invention utilizes a rare-earth metal-doped titanium catalyst prepared from an organotitanate, a rare-earth metal precursor, a carboxylic acid, and an alcohol solution. On one hand, the organotitanate and carboxylic acid form a stable titanium-organic chelate, which inhibits the hydrolytic deactivation of the organotitanate catalyst. On the other hand, the rare-earth metal precursor reacts with the titanium-organic chelate to form a titanium-rare-earth metal bimetallic active site, thus improving catalytic activity, significantly reducing polycondensation time, and obtaining a copolyester with relatively high viscosity.
[0011] In a further proposed scheme, the molar ratio of titanium to rare earth metal is 1:0.1 to 1.
[0012] Preferably, the molar ratio of titanium metal to rare earth metal is 1:0.1 to 0.6.
[0013] Since there is only one titanium atom in the organotitanate and only one rare earth metal atom in the rare earth metal precursor, the molar ratio of titanium metal to rare earth metal in this invention is the molar ratio of organotitanate and rare earth metal precursor.
[0014] In a further embodiment, the molar ratio of the carboxylic acid to all metals is (1.5–2):1; the molar ratio of the alcohol solution to all metals is (15–20):1; and all metals include titanium and rare earth metals.
[0015] In this invention, controlling the molar ratio of titanium metal to rare earth metal, the molar ratio of carboxylic acid to all metals, and the molar ratio of alcohol solution to all metals within the above ranges enables the formation of chelates. Different ratios have a significant impact on the particle size of the catalyst after subsequent calcination.
[0016] In a further embodiment, the organic titanate is selected from at least one of tetrabutyl titanate, isopropyl titanate, tetraethyl titanate, and tetramethyl titanate.
[0017] In a further embodiment, the rare earth metal precursor is selected from at least one of lanthanum acetylacetonate, lanthanum acetate, yttrium acetylacetonate, and yttrium acetate.
[0018] In a further embodiment, the carboxylic acid is selected from at least one of citric acid, tartaric acid, and malic acid; and the alcohol solution is selected from at least one of ethylene glycol, polyethylene glycol, and propylene glycol.
[0019] This invention also provides a method for preparing a rare earth metal-doped titanium-based catalyst, comprising the following steps:
[0020] (1) Add the organic titanate, rare earth metal precursor, carboxylic acid and alcohol solution to a beaker in proportion, heat and stir to form a sol solution.
[0021] (2) The sol solution is dried, and after drying, a gel-like rare earth metal-doped titanium catalyst is formed.
[0022] This invention employs a one-pot process to prepare rare earth metal-doped titanium catalysts, directly obtaining structurally complex molecules without intermediate separation, which is highly advantageous in terms of both economy and environmental friendliness.
[0023] In a further step, in step (1), the heating temperature is 60-80°C to form a uniform sol solution.
[0024] A further proposed method involves drying at a temperature of 100-120℃.
[0025] Preferably, the drying is carried out in a blower drying oven.
[0026] In this invention, the heating temperature is controlled at 60-80°C, under which titanium metal and rare earth metal can react with citric acid to form a chelate; controlling the drying temperature can further form a gel, while removing the water formed during the catalyst reaction.
[0027] The present invention also provides the application of the rare earth metal doped titanium catalyst as described above in the synthesis of aliphatic-aromatic copolyesters, or PBS, or PBST;
[0028] Preferably, in the synthesis of aliphatic-aromatic copolyesters, the esterification reaction temperature is 190-235℃, the pre-condensation reaction temperature is 230-245℃, and the final condensation reaction temperature is 250-280℃.
[0029] Preferably, in the aliphatic-aromatic copolyester synthesis system, the metal content of the rare earth metal-doped titanium catalyst is 10-100 ppm, based on the mass of the reactants.
[0030] As a specific implementation method, the method for preparing aliphatic-aromatic copolyesters using rare earth metal-doped titanium catalysts includes:
[0031] ① Dissolve the gel-state rare earth metal-doped titanium catalyst in the diol reaction raw materials according to the mass ratio of the feed to form a uniform solution; add the aromatic monomer terephthalic acid, the aliphatic monomer dicarboxylic acid, and the diol monomer containing the catalyst into the polymerization reactor according to the molar ratio of acid and alcohol, start stirring, and slowly raise the reaction temperature until the first drop of esterification fraction evaporates, which is regarded as the starting point of the esterification reaction. Slowly control the temperature to rise to 235℃. When the amount of water produced by esterification reaches more than 95% of the theoretical amount, the esterification reaction ends.
[0032] ② Turn on the water pump low vacuum system and slowly raise the temperature to 245℃. The reaction time is 40 minutes. The low vacuum pre-condensation reaction is then complete.
[0033] ③ Turn on the high vacuum system to reduce the pressure inside the reactor to below 100Pa, and at the same time slowly raise the reaction temperature to 260℃ to carry out the final polycondensation reaction. When the stirring power increases to the discharge stirring power, stop the reaction and simultaneously introduce N2 gas to press the polymer into the cold water tank for cooling. Then, granulate online to obtain aliphatic-aromatic copolyester chips and perform tests on properties such as relative viscosity.
[0034] By adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art:
[0035] 1. In the rare earth metal-doped titanium catalyst prepared by the present invention using organotitanate, rare earth metal precursor, carboxylic acid and alcohol solution, on the one hand, the organotitanate and carboxylic acid form a stable titanium-organic chelate, which can inhibit the hydrolysis and deactivation of organotitanate catalysts; on the other hand, the rare earth metal precursor reacts with the titanium-organic chelate to form a titanium-rare earth metal bimetallic active site, which can improve the catalytic reaction activity, significantly reduce the polycondensation reaction time, and obtain a copolyester with relatively high viscosity.
[0036] 2. The rare earth metal-doped titanium catalyst of the present invention is in a gel state, and the gel catalyst can form a uniform solution with the diol monomer, which is easy to apply in industry.
[0037] 3. The preparation method of the rare earth metal doped titanium catalyst of the present invention is a one-pot method, which does not require the separation of intermediates and can directly obtain molecules with complex structures, thereby saving steps and costs and being environmentally friendly.
[0038] The specific embodiments of the present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description
[0039] The accompanying drawings, as part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention, but do not constitute an undue limitation of the invention. Obviously, the drawings described below are merely some embodiments, and those skilled in the art can obtain other drawings based on these drawings without creative effort. In the drawings:
[0040] Figure 1 This refers to the case in Experiment 1 of this invention where TBT dissolves in a mixture of different amounts of BDO-H2O;
[0041] Figure 2 This refers to the situation where the TBT and the catalyst prepared in Example 1 of this invention are dissolved in a 40% BDO-H2O mixture for 30 minutes.
[0042] Figure 3 This refers to the situation where the TBT prepared in Experimental Example 1 and the catalyst prepared in Example 1 of this invention are dissolved in an 80% BDO-H2O mixture for 30 minutes.
[0043] Figure 4 This refers to the situation where the TBT and the catalyst prepared in Example 1 of this invention are dissolved in a 40% BDO-H2O mixture for 16 hours.
[0044] Figure 5 This refers to the situation where the TBT and the catalyst prepared in Example 1 of this invention are dissolved in an 80% BDO-H2O mixture for 16 hours.
[0045] Figures 2-5 In the image, the left side shows the solubility of TBT, and the right side shows the solubility of the catalyst (labeled T64) prepared in Example 1.
[0046] It should be noted that these accompanying drawings and textual descriptions are not intended to limit the scope of the invention in any way, but rather to illustrate the concept of the invention to those skilled in the art by referring to specific embodiments. Detailed Implementation
[0047] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below in conjunction with the embodiments and accompanying drawings. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.
[0048] Example 1
[0049] Example 1 provides a method for preparing a gel-state rare earth metal-doped titanium-based polyester catalyst and its catalytic synthesis of PBAT polyester. The specific preparation process and catalytic synthesis of PBAT polyester are as follows:
[0050] (1) Preparation of gel-state rare earth metal doped titanium polyester catalyst: 17g tetrabutyl titanate, 5g yttrium acetylacetonate and 24g citric acid were weighed and dissolved in 62g ethylene glycol and stirred at 80℃ for 6h to form a light yellow sol. After cooling to room temperature, the synthesized light yellow sol was placed in a 100℃ forced-air drying oven and dried for 10h to form a gel-state rare earth metal doped titanium polyester catalyst.
[0051] (2) PBAT polymerization process catalyzed by gel-state rare earth metal-doped titanium-based polyester catalyst: 213.43g of terephthalic acid (PTA), 229.45g of adipic acid (AA), and 360.16g of 1,4-butanediol (BDO) were added to a 2.0L polymerization reactor according to the above feed amounts. The gel-state polyester catalyst was first added to the BDO reactants at a dosage of 100ppm (calculated based on the total mass of the reactants, g / g) to dissolve and form a homogeneous mixture before being added to the polymerization reactor. Stirring was started, and the reaction temperature was slowly increased until the first drop of esterified fraction evaporated, considered the starting point of the esterification reaction. The reaction temperature was slowly controlled to 235℃. When the amount of water produced from the esterification reached more than 95% of the theoretical amount, the esterification reaction ended. The low-vacuum system was then started, and the temperature was slowly increased to 245℃. The reaction was completed within 40 minutes. After the low-vacuum pre-condensation reaction is completed, the high-vacuum final condensation reaction is started, the pressure inside the reactor is reduced to below 100 Pa, and the reaction temperature is slowly increased to 260°C for the final condensation reaction. When the stirring power increases to the discharge stirring power, the reaction is stopped, and N2 gas is introduced to press the polymer into the cold water tank for cooling, thus obtaining PBAT polymer, which is then tested for properties such as relative viscosity.
[0052] The test results, such as the polycondensation reaction time and the relative viscosity of the synthesized PBAT, are shown in Table 1.
[0053] Example 2
[0054] In this embodiment, the preparation of the gel-state rare earth metal-doped titanium-based polyester catalyst and its catalytic synthesis of PBAT polyester are described. The specific preparation process and catalytic polymerization reaction process are as follows:
[0055] (1) The preparation process of the gel-state rare earth metal doped titanium polyester catalyst is exactly the same as that in Example 1.
[0056] (2) The polymerization process of PBAT catalyzed by gel-state rare earth metal doped titanium polyester catalyst is exactly the same as the polymerization steps in Example 1, except that the amount of catalyst used in this example is 50 ppm.
[0057] The test results for polycondensation reaction time and relative viscosity of synthesized PBAT are shown in Table 1.
[0058] Example 3
[0059] In this embodiment, the preparation of a gel-state rare-earth metal-doped titanium-based polyester catalyst and its catalytic synthesis of PBST polyester are described in detail below:
[0060] (1) The preparation process of the gel-state rare earth metal doped titanium polyester catalyst is exactly the same as that in Example 1.
[0061] (2) PBST polymerization process catalyzed by gel-state rare earth metal-doped titanium-based polyester catalyst: 213.43g PTA, 118.09g SA, and 360.16g BDO were added to a 2.0L polymerization reactor according to the above feed amounts. The gel-state polyester catalyst was first added to the BDO reactants at a dosage of 50ppm (calculated based on the total mass of the reactants, g / g) to dissolve and form a homogeneous mixture before being added to the polymerization reactor. Stirring was started, and the reaction temperature was slowly increased until the first drop of esterified fraction evaporated, which was considered the starting point of the esterification reaction. The reaction temperature was slowly controlled to 235℃. When the amount of water produced by esterification reached more than 95% of the theoretical value, the esterification reaction ended. The low vacuum system of the water pump was started, and the temperature was slowly increased to 245℃. The reaction was completed within 40 minutes. After the low-vacuum pre-condensation reaction is completed, the high-vacuum final condensation reaction is started, the pressure inside the reactor is reduced to below 100 Pa, and the reaction temperature is slowly increased to 260°C for the final condensation reaction. When the stirring power increases to the discharge stirring power, the reaction is stopped, and N2 gas is introduced to press the polymer into the cold water tank for cooling, thus obtaining PBST polymer, which is then tested for properties such as relative viscosity.
[0062] The test results for polycondensation reaction time and relative viscosity of synthesized PBST are shown in Table 1.
[0063] Example 4
[0064] In this embodiment, the preparation of the gel-state rare earth metal-doped titanium-based polyester catalyst and its catalytic synthesis of PBAT polyester are described. The specific preparation process and catalytic polymerization reaction process are as follows:
[0065] (1) Preparation of gel-state rare earth metal doped titanium polyester catalyst: 17g tetrabutyl titanate, 2.3g yttrium acetylacetonate and 16g citric acid were weighed and dissolved in 52g ethylene glycol and stirred at 80℃ for 6h to form a light yellow sol. After cooling to room temperature, the synthesized light yellow sol was placed in a 110℃ forced-air drying oven and dried for 10h to form a gel-state rare earth metal doped titanium polyester catalyst.
[0066] (2) The polymerization process of PBAT catalyzed by the gel-state rare earth metal doped titanium polyester catalyst is exactly the same as the polymerization steps in Example 1. The difference is that the catalyst used is the rare earth metal doped titanium catalyst prepared in step (1) of this example.
[0067] The test results for polycondensation reaction time and relative viscosity of synthesized PBAT are shown in Table 1.
[0068] Example 5
[0069] In this embodiment, the preparation of the gel-state rare earth metal-doped titanium-based polyester catalyst and its catalytic synthesis of PBAT polyester are described. The specific preparation process and catalytic polymerization reaction process are as follows:
[0070] (1) Preparation of gel-state rare earth metal doped titanium polyester catalyst: 17g tetrabutyl titanate, 5.3g yttrium acetate and 24g citric acid were weighed and dissolved in 62g ethylene glycol and stirred at 80℃ for 6h to form a light yellow sol. After cooling to room temperature, the synthesized light yellow sol was placed in a 120℃ forced-air drying oven and dried for 10h to form a gel-state rare earth metal doped titanium polyester catalyst.
[0071] (2) The polymerization process of PBAT catalyzed by the gel-state rare earth metal doped titanium polyester catalyst is exactly the same as the polymerization steps in Example 1. The difference is that the catalyst used is the rare earth metal doped titanium catalyst prepared in step (1) of this example.
[0072] The test results for polycondensation reaction time and relative viscosity of synthesized PBAT are shown in Table 1.
[0073] Example 6
[0074] The preparation process and catalytic polymerization process of the gel-state rare earth metal-doped titanium-based polyester catalyst and its catalytic synthesis of PBAT polyester in this embodiment are as follows:
[0075] (1) The preparation process of the gel-state rare earth metal doped titanium polyester catalyst is exactly the same as the preparation process of the catalyst in step (1) of Example 4.
[0076] (2) The polymerization process of PBAT catalyzed by gel-state rare earth metal doped titanium polyester catalyst is exactly the same as the polymerization steps in Example 1. The difference is that the catalyst used is the rare earth metal doped titanium catalyst prepared in step (1) of this example, and the amount of catalyst used is 50 ppm.
[0077] The test results for polycondensation reaction time and relative viscosity of synthesized PBAT are shown in Table 1.
[0078] Example 7
[0079] The preparation process and catalytic polymerization process of the gel-state rare earth metal-doped titanium-based polyester catalyst and its catalytic synthesis of PBST polyester in this embodiment are as follows:
[0080] (1) The preparation process of the gel-state rare earth metal doped titanium polyester catalyst is exactly the same as the preparation process of the catalyst in step (1) of Example 5.
[0081] (2) The polymerization process of PBST catalyzed by gel-state rare earth metal doped titanium polyester catalyst is exactly the same as the polymerization steps in Example 3. The difference is that the catalyst used is the rare earth metal doped titanium catalyst prepared in step (1) of this example, and the amount of catalyst used is 50 ppm.
[0082] The test results for polycondensation reaction time and relative viscosity of synthesized PBST are shown in Table 1.
[0083] Example 8
[0084] In this embodiment, the preparation of the gel-state rare earth metal-doped titanium-based polyester catalyst and its catalytic synthesis of PBAT polyester are described. The specific preparation process and catalytic polymerization reaction process are as follows:
[0085] (1) Preparation of gel-state rare earth metal doped titanium polyester catalyst: 17g tetrabutyl titanate, 1.1g yttrium acetate and 16g citric acid were weighed and dissolved in 49g ethylene glycol and stirred at 80℃ for 6h to form a light yellow sol. After cooling to room temperature, the synthesized light yellow gel was placed in a 100℃ forced-air drying oven and dried for 10h to form a gel-state rare earth metal doped titanium polyester catalyst.
[0086] (2) The polymerization process of PBAT catalyzed by the gel-state rare earth metal doped titanium polyester catalyst is exactly the same as the polymerization steps in Example 1. The difference is that the catalyst used is the rare earth metal doped titanium catalyst prepared in step (1) of this example.
[0087] The test results for polycondensation reaction time and relative viscosity of synthesized PBAT are shown in Table 1.
[0088] Comparative Example 1
[0089] In this comparative example, the polyester catalyst is commercial tetrabutyl titanate (Aladdin). The specific process of its catalytic synthesis of PBAT polyester is exactly the same as the steps in Example 1, except that the catalyst used is commercial tetrabutyl titanate catalyst.
[0090] Table 1
[0091]
[0092] Results analysis:
[0093] Compared with commercially available tetrabutyl titanate catalysts, the polymers prepared using the catalysts of Examples 1-8 of this invention show a significant reduction in polycondensation reaction time and a significant increase in intrinsic viscosity, thereby improving catalytic efficiency and exhibiting good stability and repeatability.
[0094] Experimental Example 1: Investigation of the hydrolysis of the catalyst
[0095] Mixtures of 1,4-butanediol (BDO) and water with different mass fractions were prepared, specifically, the mass fractions of BDO in the mixtures were 10%, 40%, and 80%, respectively.
[0096] (1) Equal masses of tetrabutyl titanate (TBT) were added to equal volumes of the above-mentioned mixtures of BDO-H2O with different mass fractions and pure H2O. The results are as follows: Figure 1 As shown in the figure, precipitates appear when TBT is dissolved in mixtures of different amounts of BDO-H2O and in water.
[0097] (2) The same mass of the catalyst prepared in Example 1 and tetrabutyl titanate (TBT) were dissolved in the same volume of BDO-H2O mixture with a mass fraction of 40% and the changes were observed for 30 min.
[0098] The results are as follows Figure 2 As shown, TBT reacts with water to form a precipitate; the catalyst prepared in Example 1 (labeled as T64 in the figure) does not produce a precipitate.
[0099] (3) The same mass of the catalyst prepared in Example 1 and tetrabutyl titanate (TBT) were dissolved in the same volume of BDO-H2O mixture with a mass fraction of 80% and the changes were observed for 30 min.
[0100] The results are as follows Figure 3 As shown, TBT reacts with water to form a precipitate; the catalyst prepared in Example 1 (labeled as T64 in the figure) does not produce a precipitate.
[0101] (4) The same mass of the catalyst prepared in Example 1 and tetrabutyl titanate (TBT) were dissolved in the same volume of BDO-H2O mixture with a mass fraction of 40% and the changes were observed for 16 h.
[0102] The results are as follows Figure 4 As shown, TBT reacts with water to form a precipitate; the catalyst prepared in Example 1 (labeled as T64 in the figure) does not produce a precipitate.
[0103] (5) The same mass of the catalyst prepared in Example 1 and tetrabutyl titanate (TBT) were dissolved in the same volume of BDO-H2O mixture with a mass fraction of 80% and the changes were observed for 16 h.
[0104] The results are as follows Figure 5 As shown, TBT reacts with water to form a precipitate; the catalyst prepared in Example 1 (labeled as T64 in the figure) does not produce a precipitate.
[0105] (6) The catalyst prepared in Example 1 and the TBT catalyst were dissolved in a BDO-H2O mixture (mass fraction of 40% and 80%) for 16 hours and then treated at 80°C for 1 hour.
[0106] Results: TBT reacted with water to form a precipitate; the catalyst prepared in Example 1 did not form a precipitate.
[0107] In summary, the results are consistent: when the catalyst prepared in this invention is added to BDO-H2O mixtures of different concentrations, no obvious precipitation is observed; while tetrabutyl titanate shows obvious flocculent precipitation in BDO-H2O mixtures of different concentrations.
[0108] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.
Claims
1. A rare earth metal-doped titanium-based catalyst, characterized in that, The raw materials include the following components: organic titanate, rare earth metal precursor, carboxylic acid and alcohol solution; the rare earth metal doped titanium catalyst is in a gel state, the organic titanate and carboxylic acid form a titanium organic chelate, and the rare earth metal precursor and titanium organic chelate form a bimetallic active site.
2. The rare earth metal-doped titanium catalyst according to claim 1, characterized in that, The molar ratio of titanium to rare earth metal is 1:0.1 to 1; Preferably, the molar ratio of titanium metal to rare earth metal is 1:0.1 to 0.
6.
3. The rare earth metal-doped titanium catalyst according to claim 1, characterized in that, The molar ratio of the carboxylic acid to all metals is (1.5-2):1; the molar ratio of the alcohol solution to all metals is (15-20):1; and all metals include titanium and rare earth metals.
4. The rare earth metal-doped titanium catalyst according to any one of claims 1-3, characterized in that, The organic titanate is selected from at least one of tetrabutyl titanate, isopropyl titanate, tetraethyl titanate, and tetramethyl titanate.
5. The rare earth metal-doped titanium-based catalyst according to any one of claims 1-3, characterized in that, The rare earth metal precursor is selected from at least one of lanthanum acetylacetonate, lanthanum acetate, yttrium acetylacetonate, and yttrium acetate.
6. The rare earth metal-doped titanium catalyst according to any one of claims 1-3, characterized in that, The carboxylic acid is selected from at least one of citric acid, tartaric acid, and malic acid; the alcohol solution is selected from at least one of ethylene glycol, polyethylene glycol, and propylene glycol.
7. A method for preparing a rare earth metal-doped titanium-based catalyst as described in any one of claims 1-6, characterized in that, Includes the following steps: (1) Add the organic titanate, rare earth metal precursor, carboxylic acid and alcohol solution to a beaker in proportion, heat and stir to form a sol solution. (2) The sol solution is dried, and after drying, a gel-like rare earth metal-doped titanium catalyst is formed.
8. The preparation method according to claim 7, characterized in that, In step (1), the heating temperature is 60-80℃ to form a uniform sol solution.
9. The preparation method according to claim 7, characterized in that, The drying temperature is 100-120℃; Preferably, the drying is carried out in a blower drying oven.
10. The application of a rare earth metal-doped titanium catalyst as described in any one of claims 1-6 in the synthesis of aliphatic-aromatic copolyesters, or PBS, or PBST; Preferably, in the synthesis of aliphatic-aromatic copolyesters, the esterification reaction temperature is 190-235℃, the pre-condensation reaction temperature is 230-245℃, and the final condensation reaction temperature is 250-280℃. Preferably, in the aliphatic-aromatic copolyester synthesis system, the metal content of the rare earth metal-doped titanium catalyst is 10-100 ppm, based on the mass of the reactants.