Al-Ti catalyst and preparation method and application thereof
By preparing Al-Ti catalysts, the problems of high toxicity, high cost, and poor color of existing catalysts have been solved, realizing the synthesis of polyester with low toxicity, high activity, and low cost, meeting environmental protection requirements, and allowing it to be added simultaneously with the reactants.
Patent Information
- Application Number
- CN202410594997.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-14
- Publication Date
- 2025-11-14
AI Technical Summary
Existing catalysts such as antimony-based, germanium-based, tin-based, and titanium-based catalysts are highly toxic, costly, have poor color, or suffer from hydrolysis problems, making them difficult to replace in polyester synthesis. Furthermore, they cannot be added simultaneously with the reactants, which affects the quality of polyester.
An Al-Ti catalyst was developed by combining organoaluminum-titanium compounds. The preparation method involves reacting an organotitanium compound with a tricarboxylic acid, followed by the addition of an organoaluminum compound. The resulting Al-Ti catalyst is then synthesized in a solvent and used for the esterification and polycondensation processes in polyester synthesis.
It achieves low toxicity, low cost, high catalytic activity, and the resulting polyester has high viscosity and excellent color, meeting environmental protection requirements and can replace traditional catalysts.
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Figure CN120943857A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of polyester synthesis technology, specifically to an Al-Ti catalyst, its preparation method, and its application. Background Technology
[0002] Polyester is one of the five major engineering plastics, a general term for polymers obtained by the condensation polymerization of polyols and polyacids. It mainly includes polyethylene terephthalate (PET), polypropylene terephthalate (PTT), polybutylene terephthalate (PBT), and poly(1,4-cyclohexanedimethyl terephthalate) (PCT), and is a high-performance, widely used engineering plastic. The synthesis of polyester generally involves two steps: the first is esterification, and the second is polycondensation, both of which require the presence of a catalyst. Therefore, the catalyst plays a crucial role in the polyester production process. The activity of the catalyst in polyester synthesis is often characterized by the viscosity of the product; the higher the viscosity, the higher the activity.
[0003] For many years, researchers both domestically and internationally have conducted extensive research on catalysts for polyester synthesis. Currently, the main types of catalysts include: Antimony-based catalysts: Industrial production primarily uses antimony-based catalysts, mainly antimony trioxide, antimony acetate, and antimony glycolate. However, these catalysts are highly toxic, posing serious harm to the environment and human health. With increasing environmental awareness, there is a growing desire to develop new catalysts to replace antimony-based catalysts in polyester synthesis. Germanium-based catalysts: Commonly used catalysts include germanium dioxide and organometallic complexes of germanium. These catalysts exhibit good stability, mild reaction conditions, and fewer side reactions during the reaction process. The resulting polyester is pure white and highly transparent. However, the scarcity and high price of germanium resources limit the application of germanium-based catalysts. Tin-based catalysts: Commonly used catalysts include stannous oxalate, dibutyltin oxide, and stannous octoate. These catalysts have good catalytic activity, but the color of the synthesized polyester is not as good as that of antimony-based catalysts, and tin also has significant toxicity. Therefore, these catalysts have not been used in the industrial production of synthetic polyester. Titanium-based catalysts: Commonly used catalysts include titanium dioxide, isopropyl titanate, butyl titanate, and titanium glycolate. Their advantages include high catalytic activity and low cost. However, polyester synthesized using titanium-based catalysts tends to have a yellowish color, thus limiting their application. Aluminum-based catalysts: Organoaluminum complex catalysts have low toxicity, high activity, and are inexpensive. However, aluminum-based catalysts are prone to hydrolysis and can only be added during the polyester polycondensation stage, which also limits their industrial application.
[0004] Therefore, there is an urgent need for a novel catalyst that is less toxic, more active, cheaper, has a better color, and can be added simultaneously with polyester synthesis monomers for esterification. Summary of the Invention
[0005] To address the problems existing in the prior art, this invention provides an Al-Ti catalyst, its preparation method, and its applications. The Al-Ti catalyst proposed in this invention exhibits low toxicity, can coexist with polyesters without affecting their quality, meets environmental protection requirements while ensuring catalytic activity, and is inexpensive. It is an ideal new catalyst for synthesizing polyesters, capable of replacing traditional antimony catalysts.
[0006] One object of the present invention is to provide an Al-Ti catalyst comprising at least one organoaluminum-titanium compound having the following general structural formula:
[0007]
[0008] Wherein, R1 and R2 may be the same or different, and are each independently selected from at least one of alkyl, substituted alkyl, alkenyl, substituted alkenyl, aryl, substituted aryl, carbonyl, and hydrogen; R4 and R5 may be the same or different, and are each independently selected from at least one of alkyl, substituted alkyl, alkenyl, substituted alkenyl, aryl, substituted aryl, carbonyl, alkoxy, and hydrogen; and R4 and R5 may optionally be cyclized; R3 is selected from at least one of aliphatic hydrocarbon, substituted aliphatic hydrocarbon, aryl, and substituted aryl.
[0009] In a preferred embodiment of the present invention,
[0010] R1 and R2 may be the same or different, and are independently selected from at least one of C1-C10 alkyl, C1-C10 alkenyl, ester-substituted C1-C10 alkenyl, phenyl, quinolinyl, carbonyl, carbonyl-substituted C1-C10 alkyl, and hydrogen; and / or,
[0011] R4 and R5 may be the same or different, and are independently selected from at least one of C1-C10 alkyl, C1-C10 alkenyl, aryl-substituted C1-C10 alkyl, benzyl-substituted C1-C10 alkenyl, carbonyl, C1-C10 alkoxy, and hydrogen, and R4 and R5 are optionally cyclized; and / or,
[0012] R3 is selected from at least one of 2-hydroxypropyl (which is derived from citric acid) and phenyl.
[0013] The structure of the Al-Ti catalyst was calculated based on the principle and the amount of raw materials added.
[0014] A second objective of this invention is to provide a method for preparing an Al-Ti catalyst, which includes a step of reacting components comprising an organotitanium compound, a tricarboxylic acid, and an organoaluminum compound; preferably, the organotitanium compound is reacted with the tricarboxylic acid first, and then the organoaluminum compound is added to react and obtain the Al-Ti catalyst.
[0015] The preferred feature of the Al-Ti catalyst is that it is an Al-Ti catalyst prepared by the above-described preparation method.
[0016] In a preferred embodiment of the present invention,
[0017] The general structural formula of the organoaluminum compound is: (OR')(OR) 1 (OR) 2 Al, where R' and R 1 R 2 They may be the same or different, and are each independently selected from at least one of alkyl, substituted alkyl, alkenyl, substituted alkenyl, aryl, substituted aryl, carbonyl, and hydrogen, preferably from at least one of C1-C10 alkyl, C1-C10 alkenyl, ester-substituted C1-C10 alkenyl, phenyl, quinolinyl, carbonyl, carbonyl-substituted C1-C10 alkyl, and hydrogen; preferably,
[0018] The organoaluminum compound is selected from at least one of chelated aluminum complexes, benzene-containing aluminum compounds (aluminum compounds containing benzene rings), aluminum alkoxides, and aluminum carboxylate compounds; more preferably,
[0019] The chelated aluminum complex is selected from at least one of aluminum acetylacetonate, tris(ethylacetoacetyl)aluminum, benzoylacetone aluminum, and dibenzylacetone aluminum; and / or,
[0020] The phenyl-aluminum compound is selected from at least one of aluminum phenyl oxybenzoate and 8-hydroxyquinoline aluminum; and / or,
[0021] The aluminum alkoxide compound is selected from at least one of aluminum triethanolamine, aluminum butoxide, and aluminum isopropoxide; and / or,
[0022] The aluminum carboxylate compound is selected from at least one of aluminum triformate, aluminum acetate, and aluminum propionate.
[0023] The organoaluminum compounds mentioned above can all be commercially available or prepared by any method prior to the art.
[0024] In a preferred embodiment of the present invention,
[0025] The general structural formula of the organotitanium compound is: Ti(OR) 4 (OR) 5 (OR) 6 (OR) 7 ), where R 4 R 5 R 6 R 7 They may be the same or different, and are each independently selected from at least one of alkyl, substituted alkyl, alkenyl, substituted alkenyl, aryl, substituted aryl, carbonyl, alkoxy, and hydrogen, and R 4R 5 R 6 R 7 Any two of them can be chosen to form a ring; preferably,
[0026] R 4 R 5 R 6 R 7 Whether the groups are the same or different, each independently selected from at least one of C1-C10 alkyl, C1-C10 alkenyl, aryl-substituted C1-C10 alkyl, benzyl-substituted C1-C10 alkenyl, carbonyl, C1-C10 alkoxy, and hydrogen, and R 4 R 5 R 6 R 7 Any two of them can be chosen to form a ring; more preferably,
[0027] The organotitanium compound is selected from at least one of chelated titanium complexes, organotitanate esters, and titanium alkoxides; more preferably,
[0028] The chelated titanium complex is selected from at least one of titanium acetylacetone and titanium ethyl acetoacetate; titanium ethyl acetoacetate is a chelate of titanium ethyl acetoacetate; and / or,
[0029] The organic titanate is selected from at least one of ethyl titanate, isopropyl titanate, and butyl titanate; and / or,
[0030] The titanium alkoxide compound is selected from at least one of titanium glycol, titanium 1,3-propanediol, and titanium 1,4-butanediol.
[0031] The organotitanium compounds mentioned above can all be commercially available or prepared by any method prior to the art.
[0032] In a preferred embodiment of the present invention,
[0033] The general structural formula of the tribasic acid is: Wherein, R is selected from at least one of aliphatic hydrocarbon group, substituted aliphatic hydrocarbon group, aryl group, and substituted aryl group, preferably from at least one of 2-hydroxypropyl group and phenyl group; preferably...
[0034] The tricarboxylic acid is selected from at least one of citric acid and benzoic acid, preferably from at least one of pyromellitic acid, trimellitic acid, and citric acid.
[0035] In a preferred embodiment of the present invention,
[0036] The molar ratio of the organotitanium compound, the tribasic acid, and the organoaluminum compound is 1:(1-3):(1-1.5), preferably 1:(1.1-2):(1-1.1); and / or,
[0037] The reaction conditions for the organotitanium compound with the tricarboxylic acid include: reacting at 100-200℃ for 2-20 h, preferably at 140-180℃ for 5-10 h; and / or,
[0038] The reaction conditions for adding organoaluminum compounds include: continuing the reaction at 150-250°C for 2-20 hours, preferably continuing the reaction at 190-230°C for 8-12 hours.
[0039] In a preferred embodiment of the present invention,
[0040] The Al-Ti catalyst is prepared in the presence of a solvent, preferably N,N-dimethylformamide; preferably, the molar ratio of the solvent to the organotitanium compound is (1-10):1.
[0041] A third objective of this invention is to provide a catalyst for polyester synthesis, comprising an Al-Ti catalyst according to one objective of this invention or an Al-Ti catalyst obtained by the preparation method according to another objective of this invention.
[0042] The fourth objective of this invention is to provide a method for synthesizing polyester, comprising the steps of esterifying and polycondensing a component including a dicarboxylic acid and a diol in the presence of a polyester synthesis catalyst as described in the third objective of this invention to obtain a polyester.
[0043] In a preferred embodiment of the present invention,
[0044] The molar ratio of the dicarboxylic acid to the diol is 1:(1.0-1.5), preferably 1:(1.1-1.3); and / or,
[0045] The mass ratio of the catalyst for polyester synthesis to the dicarboxylic acid is (0.00001-0.001):1, preferably (0.00001-0.00005):1; and / or,
[0046] The dicarboxylic acid is selected from at least one of terephthalic acid and its derivatives, furanyl dicarboxylic acid and its derivatives; and / or
[0047] The diol is selected from any one of ethylene glycol, propylene glycol, butanediol, and 1,4-cyclohexanediethanol.
[0048] The polyester is preferably any one of polyethylene terephthalate (PET), polypropylene terephthalate (PTT), polybutylene terephthalate (PBT), and poly(1,4-cyclohexanedimethyl terephthalate) (PCT).
[0049] In this invention, there are no special restrictions on the esterification and polycondensation process conditions, and conventional process conditions in the field can be used.
[0050] This invention has the following characteristics:
[0051] The Al-Ti catalyst proposed in this invention for polyester synthesis has low toxicity, can be added simultaneously with the monomers in the polyester synthesis reaction, and can coexist with the product polyester without affecting its quality (such as color). It has high reactivity with the synthesized polyester, and the viscosity of the obtained polyester is above 0.67 dL / g. While ensuring catalytic activity, it meets environmental protection requirements and is low in cost. It is an ideal new catalyst that can replace traditional antimony-based catalysts. Detailed Implementation
[0052] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.
[0053] Unless otherwise specified, the raw materials used in the embodiments and comparative examples of this invention are all disclosed in the prior art, such as those that can be directly purchased or prepared according to the preparation methods disclosed in the prior art.
[0054] The preparation process of aluminum dibenzylacetone in this invention is as follows: Dibenzylacetone and sodium acetate are dissolved in methanol (molar ratio of methanol to dibenzylacetone is 3:1) at a molar ratio of 1:1, and then aluminum trichloride (molar ratio of aluminum trichloride to dibenzylacetone is 3:1) is added. The mixture is heated to 64°C and stirred under reflux for 2 hours in the absence of air. After cooling, it is filtered to obtain aluminum dibenzylacetone.
[0055] The preparation process of 1,3-propanediol titanium in this invention is as follows: Weigh 10.6g of 1,3-propanediol and 23.69g of tetrabutyl titanate. Pour 1,3-propanediol into a round-bottom flask, add 60mL of anhydrous ethanol for dilution, stir, heat to 75℃, add tetrabutyl titanate dropwise using a constant pressure dropping funnel, the dropwise addition time is 25min, the reaction time is 3h, then cool, filter, wash with anhydrous ethanol, and dry in an 80℃ forced-air drying oven for 12h to obtain 1,3-propanediol titanium.
[0056] Intrinsic viscosity was determined using an Ubbelohde viscometer at 25°C.
[0057] Colorimetric (b-value) test method: The sample is first dried at 120℃ for 24 hours. The sieved sample is placed in the sample cup, ensuring the sample is packed tightly. The cup is then placed on the measuring hole, and the colorimetric (b-value) of the sample is measured. The test is performed at approximately 120° intervals, for a total of three points. The average value is then taken. A higher b-value indicates a greater degree of yellowing of the sample.
[0058] Example 1
[0059] Preparation of Al-Ti catalysts:
[0060] Isopropyl titanate and trimesic acid (molar ratio 1:1.3) were added to N,N-dimethylformamide (molar ratio of N,N-dimethylformamide to isopropyl titanate 3:1) and reacted at 160 °C for 8 h. Then aluminum acetate (molar ratio of aluminum acetate to isopropyl titanate 1:1) was added and the reaction was continued at 210 °C for 10 h. The resulting product was washed three times each with N,N-dimethylformamide and acetone, and dried to obtain the catalyst aluminum acetate-trimethylformamide-isopropyl titanate (i.e., Al-Ti catalyst).
[0061] The polyester preparation process was carried out in a stirred batch reactor. The monomers used were ethylene glycol and terephthalic acid in a molar ratio of 1.3:1. The catalyst used was the aforementioned Al-Ti catalyst, with a catalyst dosage of 0.004% of the mass of terephthalic acid in the monomers. The monomers and catalyst were added to the reactor together and stirred until homogeneous. Esterification was then carried out at 240°C. After the water output reached more than 95% of the theoretical amount, the temperature was increased and a vacuum was established for polycondensation at 275°C. The pressure inside the reactor was slowly reduced to a final pressure of 50 Pa, and the reaction time was 1.5 h (starting from the establishment of the vacuum). After the polycondensation reaction was completed, stirring was stopped (stirring is required during both esterification and polycondensation processes at a stirring rate of 300 rpm). The resulting product was rapidly cooled at 200 Pa, drawn into fibers, and granulated to obtain the polyester product.
[0062] Example 2
[0063] The preparation method of the Al-Ti catalyst is the same as that in Example 1, except that the added organoaluminum compound is aluminum butoxide, the organotitanium compound is titanium glycolate, and the tricarboxylic acid is citric acid.
[0064] The polyester preparation process was carried out in a stirred batch reactor. The monomers used were ethylene glycol and terephthalic acid in a molar ratio of 1.3:1. The catalyst used was the aforementioned Al-Ti catalyst, added at 0.002% of the mass of terephthalic acid in the monomers. The monomers and catalyst were added to the reactor and stirred until homogeneous. Esterification was then carried out at 245°C. After the water output reached more than 95% of the theoretical amount, the temperature was increased and a vacuum was established for polycondensation at 278°C. The pressure inside the reactor was slowly reduced to a final pressure of 60 Pa, and the reaction time was 1.5 h (starting from the establishment of the vacuum). After the polycondensation reaction was completed, stirring was stopped (stirring is required during both esterification and polycondensation processes at a stirring rate of 300 rpm). The resulting product was rapidly cooled at 200 Pa, drawn into fibers, and granulated to obtain the polyester product.
[0065] Example 3
[0066] The preparation method of the Al-Ti catalyst is the same as that in Example 1, except that the added organoaluminum compound is aluminum acetylacetonate, the organotitanium compound is tetrabutyl titanate, and the tricarboxylic acid is trimellitic acid.
[0067] The polyester preparation process was carried out in a stirred batch reactor. The monomers used were ethylene glycol and terephthalic acid in a molar ratio of 1.2:1. The catalyst used was the aforementioned Al-Ti catalyst, added at 0.003% of the mass of terephthalic acid in the monomers. The monomers and catalyst were added to the reactor and stirred until homogeneous. Esterification was then carried out at 260°C. After the water output reached more than 95% of the theoretical amount, the temperature was increased and a vacuum was established for polycondensation at 270°C. The pressure inside the reactor was slowly reduced to a final pressure of 55 Pa, and the reaction time was 1 hour (starting from the establishment of the vacuum). After the polycondensation reaction was completed, stirring was stopped (stirring is required during both esterification and polycondensation processes at a stirring rate of 300 rpm). The resulting product was rapidly cooled at 200 Pa, drawn into fibers, and granulated to obtain the polyester product.
[0068] Example 4
[0069] The preparation method of the Al-Ti catalyst is the same as that in Example 1, except that the added organoaluminum compound is phenylaluminate, the organotitanium compound is titanium acetylacetonate, and the tricarboxylic acid is citric acid.
[0070] The polyester preparation process was carried out in a stirred batch reactor. The monomers used were 1,3-propanediol and terephthalic acid in a molar ratio of 1.1:1. The catalyst used was the aforementioned Al-Ti catalyst, with an amount of 0.002% of the mass of terephthalic acid in the monomers. The monomers and catalyst were added to the reactor together and stirred until homogeneous. Esterification was then carried out at 250°C. After the water output reached more than 95% of the theoretical amount, the temperature was increased and a vacuum was established for polycondensation at 276°C. The pressure inside the reactor was slowly reduced to a final pressure of 70 Pa, and the reaction time was 1.5 h (starting from the establishment of the vacuum). After the polycondensation reaction was completed, stirring was stopped (stirring is required during both esterification and polycondensation processes at a stirring rate of 300 rpm). The resulting product was rapidly cooled at 200 Pa, drawn into fibers, and granulated to obtain the polyester product.
[0071] Example 5
[0072] The preparation method of the Al-Ti catalyst is the same as in Example 1, except that the added organoaluminum compound is aluminum triformate, the organotitanium compound is titanium 1,3-propanediol, and the tricarboxylic acid is pyromellitic acid.
[0073] The polyester preparation process was carried out in a stirred batch reactor. The monomers used were 1,3-propanediol and terephthalic acid in a molar ratio of 1.3:1. The catalyst used was the aforementioned Al-Ti catalyst, with an amount of 0.001% of the mass of terephthalic acid in the monomers. The monomers and catalyst were added to the reactor together and stirred until homogeneous. Esterification was then carried out at 255°C. After the water output reached more than 95% of the theoretical amount, the temperature was increased and a vacuum was established for polycondensation at 270°C. The pressure inside the reactor was slowly reduced to a final pressure of 50 Pa, and the reaction time was 1 hour (starting from the establishment of the vacuum). After the polycondensation reaction was completed, stirring was stopped (stirring is required during both esterification and polycondensation processes at a stirring rate of 300 rpm). The resulting product was rapidly cooled at 200 Pa, drawn into fibers, and granulated to obtain the polyester product.
[0074] Example 6
[0075] The preparation method of the Al-Ti catalyst is the same as that in Example 1, except that the added organoaluminum compound is aluminum isopropoxide, the organotitanium compound is titanium acetylacetonate, and the tricarboxylic acid is citric acid.
[0076] The polyester preparation process was carried out in a stirred batch reactor. The monomers used were 1,4-butanediol and terephthalic acid in a molar ratio of 1.2:1. The catalyst used was the aforementioned Al-Ti catalyst, with an amount of 0.001% of the mass of terephthalic acid in the monomers. The monomers and catalyst were added to the reactor together and stirred until homogeneous. Esterification was then carried out at 260°C. After the water output reached more than 95% of the theoretical amount, the temperature was increased and a vacuum was established for polycondensation at 280°C. The pressure inside the reactor was slowly reduced to a final pressure of 60 Pa, and the reaction time was 1.5 h (starting from the establishment of the vacuum). After the polycondensation reaction was completed, stirring was stopped (stirring is required during both esterification and polycondensation processes at a stirring rate of 300 rpm). The resulting product was rapidly cooled at 200 Pa, drawn into fibers, and granulated to obtain the polyester product.
[0077] Example 7
[0078] The preparation method of the Al-Ti catalyst is the same as that in Example 1, except that the added organoaluminum compound is aluminum triethanolamine, the organotitanium compound is ethyl titanate, and the tricarboxylic acid is trimellitic acid.
[0079] The polyester preparation process was carried out in a stirred batch reactor. The monomers used were 1,4-butanediol and terephthalic acid in a molar ratio of 1.3:1. The catalyst used was the aforementioned Al-Ti catalyst, with an amount of 0.005% of the mass of terephthalic acid in the monomers. The monomers and catalyst were added to the reactor together and stirred until homogeneous. Esterification was then carried out at 245°C. After the water output reached more than 95% of the theoretical amount, the temperature was increased and a vacuum was established for polycondensation at 270°C. The pressure inside the reactor was slowly reduced to a final pressure of 50 Pa, and the reaction time was 1 hour (starting from the establishment of the vacuum). After the polycondensation reaction was completed, stirring was stopped (stirring is required during both esterification and polycondensation processes at a stirring rate of 300 rpm). The resulting product was rapidly cooled at 200 Pa, drawn into fibers, and granulated to obtain the polyester product.
[0080] Example 8
[0081] The preparation method of the Al-Ti catalyst is the same as in Example 1, except that the added organoaluminum compound is aluminum isopropoxide, the organotitanium compound is titanium 1,4-butanediol, and the tricarboxylic acid is pyromellitic acid.
[0082] The polyester preparation process was carried out in a stirred batch reactor. The monomers used were 1,4-butanediol and terephthalic acid in a molar ratio of 1.3:1. The catalyst used was the aforementioned Al-Ti catalyst, with an amount of 0.004% of the mass of terephthalic acid in the monomers. The monomers and catalyst were added to the reactor together and stirred until homogeneous. Esterification was then carried out at 255°C. After the water output reached more than 95% of the theoretical amount, the temperature was increased and a vacuum was established for polycondensation at 275°C. The pressure inside the reactor was slowly reduced to a final pressure of 70 Pa, and the reaction time was 1.5 h (starting from the establishment of the vacuum). After the polycondensation reaction was completed, stirring was stopped (stirring is required during both esterification and polycondensation processes at a stirring rate of 300 rpm). The resulting product was rapidly cooled at 200 Pa, drawn into fibers, and granulated to obtain the polyester product.
[0083] Example 9
[0084] The preparation method of the Al-Ti catalyst is the same as in Example 1, except that the added organoaluminum compound is dibenzylacetone aluminum, the organotitanium compound is tetrabutyl titanate, and the tricarboxylic acid is trimellitic acid.
[0085] The polyester preparation process was carried out in a stirred batch reactor. The monomers used were 1,4-cyclohexanediethanol and terephthalic acid in a molar ratio of 1.1:1. The catalyst used was the aforementioned Al-Ti catalyst, with an amount of 0.005% of the mass of terephthalic acid in the monomers. The monomers and catalyst were added to the reactor together and stirred until homogeneous. Esterification was then carried out at 245°C. After the water output reached more than 95% of the theoretical amount, the temperature was increased and a vacuum was established for polycondensation at 277°C. The pressure inside the reactor was slowly reduced to a final pressure of 50 Pa, and the reaction time was 1.5 h (starting from the establishment of the vacuum). After the polycondensation reaction was completed, stirring was stopped (stirring is required during both esterification and polycondensation processes at a stirring rate of 300 rpm). The resulting product was rapidly cooled at 200 Pa, drawn into fibers, and granulated to obtain the polyester product.
[0086] Example 10
[0087] The preparation method of the Al-Ti catalyst is the same as that in Example 1, except that the added organoaluminum compound is aluminum propionate, the organotitanium compound is titanium glycolate, and the tricarboxylic acid is pyromellitic acid.
[0088] The polyester preparation process was carried out in a stirred batch reactor. The monomers used were 1,4-cyclohexanediethanol and terephthalic acid in a molar ratio of 1.3:1. The catalyst used was the aforementioned Al-Ti catalyst, with an amount of 0.002% of the mass of terephthalic acid in the monomers. The monomers and catalyst were added to the reactor together and stirred until homogeneous. Esterification was then carried out at 255°C. After the water output reached more than 95% of the theoretical amount, the temperature was increased and a vacuum was established for polycondensation at 273°C. The pressure inside the reactor was slowly reduced to a final pressure of 60 Pa, and the reaction time was 1 hour (starting from the establishment of the vacuum). After the polycondensation reaction was completed, stirring was stopped (stirring is required during both esterification and polycondensation processes at a stirring rate of 300 rpm). The resulting product was rapidly cooled at 200 Pa, drawn into fibers, and granulated to obtain the polyester product.
[0089] Comparative Example 1
[0090] The polyester preparation process was carried out in a stirred batch reactor. The monomers used were ethylene glycol and terephthalic acid in a molar ratio of 1.3:1. The catalyst was a mixture of aluminum acetate and isopropyl titanate (molar ratio of aluminum acetate to isopropyl titanate was 1:1), with the catalyst dosage being 0.004% of the mass of terephthalic acid in the monomers. After adding the monomers to the reactor and stirring thoroughly, an esterification reaction was carried out at 240℃. Once the water yield reached more than 95% of the theoretical amount, the catalyst was added, the temperature was increased, and a vacuum was established for a polycondensation reaction at 275℃. The pressure inside the reactor was slowly reduced until a final pressure of 50 Pa was reached, and the reaction time was 1.5 h (starting from the establishment of the vacuum). After the polycondensation reaction was completed, stirring was stopped (stirring was required during both esterification and polycondensation processes at a stirring rate of 300 rpm). The resulting product was rapidly cooled at 200 Pa, drawn into fibers, and granulated to obtain the polyester product.
[0091] In Comparative Example 1, a mixture of aluminum acetate and isopropyl titanate was used as a catalyst. If it were added during the esterification process, it would decompose. Therefore, it could only be added during the polycondensation stage.
[0092] The intrinsic viscosity and b-value of the polyesters obtained in Examples 1-10 and Comparative Example 1 are shown in Table 1:
[0093] Table 1
[0094] Polyester Intrinsic viscosity (dL / g) b value Example 1 PET 0.72 2.1 Example 2 PET 0.69 2.6 Example 3 PET 0.67 2.0 Example 4 PTT 0.77 3.1 Example 5 PTT 0.75 2.5 Example 6 PBT 0.79 2.6 Example 7 PBT 0.78 2.7 Example 8 PBT 0.79 3.2 Example 9 PCT 0.81 2.9 Example 10 PCT 0.83 2.2 Comparative Example 1 PET 0.64 27.8
[0095] As can be seen from Example 1, Comparative Example 1, and Table 1, compared with the traditional method of simply mixing aluminum-based catalysts and titanium-based catalysts to prepare polyester (Comparative Example 1), the Al-Ti catalyst prepared in Example 1 of this invention, when used as a polyester synthesis catalyst, not only ensures the high activity of the catalyst (manifested as high intrinsic viscosity of the polyester), but also produces polyester with excellent color, achieving very good technical results.
[0096] As can be seen from Examples 1-10 and Table 1, the Al-Ti catalyst proposed in this invention for polyester synthesis can be added simultaneously with the monomers in the polyester synthesis reaction and can coexist with the product polyester without affecting its quality (such as color). It has high reactivity with the synthesized polyester, and the viscosity of the obtained polyester is above 0.67 dL / g. While ensuring catalytic activity, it meets environmental protection requirements and is low in cost.
Claims
1. An Al-Ti catalyst comprising at least one organoaluminum-titanium compound having the following general structural formula: in, R1 and R2 may be the same or different, and are each independently selected from at least one of alkyl, substituted alkyl, alkenyl, substituted alkenyl, aryl, substituted aryl, carbonyl, and hydrogen. R4 and R5 may be the same or different, and are each independently selected from at least one of alkyl, substituted alkyl, alkenyl, substituted alkenyl, aryl, substituted aryl, carbonyl, alkoxy, and hydrogen. R4 and R5 may optionally be cyclized. R3 is selected from at least one of aliphatic hydrocarbon, substituted aliphatic hydrocarbon, aryl, and substituted aryl.
2. The Al-Ti catalyst as described in claim 1, characterized in that: R1 and R2 may be the same or different, and are independently selected from at least one of C1-C10 alkyl, C1-C10 alkenyl, ester-substituted C1-C10 alkenyl, phenyl, quinolinyl, carbonyl, carbonyl-substituted C1-C10 alkyl, and hydrogen; and / or, R4 and R5 may be the same or different, and are independently selected from at least one of C1-C10 alkyl, C1-C10 alkenyl, aryl-substituted C1-C10 alkyl, benzyl-substituted C1-C10 alkenyl, carbonyl, C1-C10 alkoxy, and hydrogen, and R4 and R5 are optionally cyclized; and / or, R3 is selected from at least one of 2-hydroxypropyl and phenyl.
3. A method for preparing an Al-Ti catalyst as described in any one of claims 1-2, comprising the step of reacting a component including an organotitanium compound, a tribasic acid, and an organoaluminum compound; preferably, the organotitanium compound is reacted with the tribasic acid first, and then the organoaluminum compound is added to react and obtain the Al-Ti catalyst.
4. The preparation method according to claim 3, characterized in that: The general structural formula of the organoaluminum compound is: (OR')(OR) 1 (OR) 2 Al, where R' and R 1 R 2 They may be the same or different, and are each independently selected from at least one of alkyl, substituted alkyl, alkenyl, substituted alkenyl, aryl, substituted aryl, carbonyl, and hydrogen; preferably, The organoaluminum compound is selected from at least one of chelated aluminum complexes, benzene-containing aluminum compounds, aluminum alkoxides, and aluminum carboxylate compounds; more preferably, The chelated aluminum complex is selected from at least one of aluminum acetylacetonate, tris(ethylacetoacetyl)aluminum, benzoylacetone aluminum, and dibenzylacetone aluminum; and / or, The phenyl-aluminum compound is selected from at least one of aluminum phenyl oxybenzoate and 8-hydroxyquinoline aluminum; and / or, The aluminum alkoxide compound is selected from at least one of aluminum triethanolamine, aluminum butoxide, and aluminum isopropoxide; and / or, The aluminum carboxylate compound is selected from at least one of aluminum triformate, aluminum acetate, and aluminum propionate.
5. The preparation method according to claim 3, characterized in that: The general structural formula of the organotitanium compound is: Ti(OR) 4 (OR) 5 (OR) 6 (OR) 7 ), where R 4 R 5 R 6 R 7 They may be the same or different, and are each independently selected from at least one of alkyl, substituted alkyl, alkenyl, substituted alkenyl, aryl, substituted aryl, carbonyl, alkoxy, and hydrogen, and R 4 R 5 R 6 R 7 Any two of them can be chosen to form a ring; preferably, The organotitanium compound is selected from at least one of chelated titanium complexes, organotitanate esters, and titanium alkoxides; more preferably, The chelated titanium complex is selected from at least one of titanium acetylacetone and titanium ethyl acetoacetate; and / or The organic titanate is selected from at least one of ethyl titanate, isopropyl titanate, and butyl titanate; and / or, The titanium alkoxide compound is selected from at least one of titanium glycol, titanium 1,3-propanediol, and titanium 1,4-butanediol.
6. The preparation method according to claim 3, characterized in that: The general structural formula of the tribasic acid is: Wherein, R is selected from at least one of aliphatic hydrocarbon group, substituted aliphatic hydrocarbon group, aryl group, and substituted aryl group, preferably from at least one of 2-hydroxypropyl group and phenyl group; preferably... The tricarboxylic acid is selected from at least one of citric acid and tricresylbenzene.
7. The preparation method according to claim 3, characterized in that: The molar ratio of the organotitanium compound, the tribasic acid, and the organoaluminum compound is 1:(1-3):(1-1.5), preferably 1:(1.1-2):(1-1.1); and / or, The reaction conditions for the organotitanium compound with the tricarboxylic acid include: reacting at 100-200°C for 2-20 h, preferably at 140-180°C for 5-10 h; and / or, The reaction conditions for adding organoaluminum compounds include: continuing the reaction at 150-250°C for 2-20 hours, preferably continuing the reaction at 190-230°C for 8-12 hours.
8. A catalyst for polyester synthesis, comprising the Al-Ti catalyst according to any one of claims 1-2 or the Al-Ti catalyst obtained by the preparation method according to any one of claims 3-7.
9. A method for synthesizing polyester, comprising the steps of esterifying and polycondensing a component including a dicarboxylic acid and a diol in the presence of the polyester synthesis catalyst of claim 8 to obtain a polyester.
10. The method as described in claim 9, characterized in that: The molar ratio of the dicarboxylic acid to the diol is 1:(1.0-1.5), preferably 1:(1.1-1.3); and / or, The mass ratio of the catalyst for polyester synthesis to the dicarboxylic acid is (0.00001-0.001):1, preferably (0.00001-0.00005):1; and / or, The dicarboxylic acid is selected from at least one of terephthalic acid and its derivatives, furanyl dicarboxylic acid and its derivatives; and / or The diol is selected from any one of ethylene glycol, propylene glycol, butanediol, and 1,4-cyclohexanediethanol.