Titanium-based catalyst, its preparation method and application

Abstract

The application discloses a titanium-based catalyst and a preparation method and application thereof. The titanium-based catalyst comprises a reaction product and / or mixture of the following components: (1) a titanium-containing compound, (2) a monobasic acid, (3) a hydroxyl carboxylic acid, (4) an optional solvent. The method comprises mixing raw materials including the titanium-containing compound, the monobasic acid, the hydroxyl carboxylic acid and the optional solvent, and performing reaction to obtain the titanium-based catalyst. The catalyst has excellent hydrolysis resistance and high catalytic activity, and the polyester obtained by using the catalyst has high intrinsic viscosity and excellent color phase.

Description

Technical Field

[0001] This invention belongs to the field of catalysts, and particularly relates to titanium-based catalysts. Specifically, it relates to a titanium-based catalyst, its preparation method, and its application. Background Technology

[0002] Polyesters are polymers obtained by polycondensation of polyols and polyacids, including aromatic polyesters such as polyethylene terephthalate and polybutylene terephthalate; aliphatic polyesters such as polybutylene succinate; and aliphatic-aromatic copolyesters such as polybutylene terephthalate-adipate. These polyesters are widely used in modern life.

[0003] Catalysts commonly used in polyester production include antimony-based and titanium-based catalysts. Antimony-based catalysts offer excellent overall performance, but their heavy metal content limits their application. Titanium-based catalysts, with their high activity and non-toxicity, have become a focus of research and application in the polyester industry in recent years, particularly in the applications of polybutylene terephthalate (PET), polybutylene succinate (PET), and polybutylene adipate (PEA), where highly active titanium-based catalysts are the primary choice. However, traditional titanium-based catalysts are prone to hydrolysis and discoloration, causing challenges in their use.

[0004] CN102718958A relates to a titanium-based polyester catalyst, comprising a reaction product of (A) an alkyl titanate, (B) an alcohol, (C) a 2-hydroxycarboxylic acid, and (D) a base, wherein the reaction product is supported on nano-sized attapulgite. This patent also provides a method for preparing the titanium-based polyester catalyst, which involves mixing a 2-hydroxy acid and water, adding an alkyl titanate to react, then adding an alkaline solution to adjust the pH to 6, adding a diol for dilution, concentrating, then diluting the nano-attapulgite with a diol, adding the concentrate, mixing uniformly, and removing water under vacuum to obtain the polyester catalyst. The polyester catalyst of this patent significantly improves the color, quality, and performance of the polyester product.

[0005] CN101942078A relates to a titanium-based polyester catalyst for the preparation of polyester, mainly addressing the problems of poor storage stability, easy discoloration under light, poor thermal stability, and color difference of liquid titanium-based polyester catalysts in previous technologies. The technical solution employing a titanium-based polyester catalyst for the preparation of polyester, comprising the following raw materials reacting at a temperature of 0–200°C for a reaction time of 0.5–10 hours, yields the following reaction products: (A) a titanium compound having the general formula Ti(OR)4, where R is an alkyl group selected from 1–10 carbon atoms; (B) a diol selected from 2–10 carbon atoms; (C) at least one metal compound selected from element IA of the periodic table; (D) at least one metal compound selected from element IIA, IB, IIB, VIIB, and VIII of the periodic table; (E) at least one aliphatic organic acid selected from organic acids; and (F) at least one phosphate ester compound selected from phosphorus compounds. This solution effectively solves the problems and can be used in the industrial production of polyester.

[0006] As mentioned above, the prior art discloses the use of hydroxyl titanate for hydrolysis resistance treatment. Although this technique imparts good hydrolytic stability to titanium catalysts, it also severely reduces the activity of the catalysts. Summary of the Invention

[0007] To overcome the problems existing in the prior art, the present invention provides a titanium-based catalyst, its preparation method and application. In this invention, a titanium compound is modified by a small amount of monobasic acid and hydroxycarboxylic acid to obtain a liquid polycondensation titanium-based catalyst with high activity and good hydrolysis resistance. When polyester is prepared using this catalyst, the activity and chip color are better than those obtained by using titanate ester as catalyst.

[0008] One of the objectives of this invention is to provide a titanium-based catalyst comprising reaction products and / or mixtures of the following components: (1) a titanium-containing compound, (2) a monobasic acid, (3) a hydroxycarboxylic acid, and (4) an optional solvent.

[0009] In a preferred embodiment, the titanium-containing compound is a compound having the general formula Ti(OR)4, wherein R is selected from C1 to C2. 10 Straight-chain alkyl groups, C1-C 10 Branched alkyl groups or C1-C 10 Aryl groups.

[0010] In a further preferred embodiment, the titanium-containing compound is a compound having the general formula Ti(OR)4, wherein R is selected from C1-C6 straight-chain alkyl or C1-C6 branched alkyl, such as butyl or isopropyl.

[0011] In a further preferred embodiment, the titanium-containing compound is selected from at least one of tetraethyl titanate, tetrabutyl titanate, and tetraisopropyl titanate.

[0012] In a preferred embodiment, the monocarboxylic acid is a compound containing a carboxyl group and / or a sulfonic acid group.

[0013] In a further preferred embodiment, the monocarboxylic acid is selected from at least one of aliphatic organic acids containing a carboxyl group and / or a sulfonic acid group, and aromatic organic acids containing a carboxyl group and / or a sulfonic acid group.

[0014] In a further preferred embodiment, the monocarboxylic acid is selected from C1-C6 groups containing a carboxyl group and / or a sulfonic acid group. 18 Straight-chain or branched organic acids (preferably C1-C4 straight-chain or branched organic acids), C6-C6 organic acids containing one carboxyl group and / or sulfonic acid group. 20 Aromatic organic acids.

[0015] Most preferably, the monocarboxylic acid does not contain hydroxyl groups at the α and / or β positions, and more preferably, the monocarboxylic acid does not contain hydroxyl groups.

[0016] For example, the monocarboxylic acid is selected from at least one of acetic acid, propionic acid, butyric acid, and formic acid.

[0017] In a preferred embodiment, the molar ratio of the titanium compound to the monocarboxylic acid is 1:(0.2-5.0), preferably 1:(0.5-2.0), more preferably 1:(1.0-2.0), for example 1:(1.5-2.0), wherein the molar amount of the titanium compound is expressed as the molar amount of titanium element therein, and the molar amount of the monocarboxylic acid is expressed as the molar amount of molecules.

[0018] Among them, the pretreatment of titanate with monocarboxylic acid can reduce the inhibition of titanium catalyst activity by hydroxycarboxylic acid and improve the overall performance of the catalyst.

[0019] For example, the molar ratio of the titanium compound to the monocarboxylic acid is 1:0.2, 1:0.5, 1:1.0, 1:1.5, 1:2.0, 1:2.5, 1:3.0, 1:3.5, 1:4.0, 1:4.5, or 1:5.0, wherein the molar amount of the titanium-containing compound is expressed as the molar amount of titanium element therein, and the molar amount of the monocarboxylic acid is expressed as the molar amount of molecules.

[0020] In a preferred embodiment, the hydroxycarboxylic acid is an organic acid containing one or more hydroxyl groups, preferably an organic acid containing 1 to 3 hydroxyl groups, such as an organic acid containing 1 or 2 hydroxyl groups.

[0021] In a further preferred embodiment, the hydroxycarboxylic acid is selected from at least one of citric acid, lactic acid, malic acid, tartaric acid, 2-hydroxyglutaric acid, 2-hydroxybutyric acid, glycolic acid, mandelic acid, and salicylic acid.

[0022] In a further preferred embodiment, the hydroxyl group in the hydroxycarboxylic acid is located at the α and / or β position of the hydroxycarboxylic acid.

[0023] Hydroxycarboxylic acids are a class of substances commonly used to modify titanium-based catalysts. They are inexpensive and readily available, and their chelation with titanium atoms can effectively inhibit the hydrolysis of titanate esters.

[0024] In a preferred embodiment, the molar ratio of the titanium-containing compound to the hydroxycarboxylic acid is 1:(0.4-4.0), preferably 1:(1.2-4.0), wherein the molar amount of the hydroxycarboxylic acid is the sum of the molar amounts of hydroxyl and carboxyl groups, and the molar amount of the titanium-containing compound is the molar amount of titanium element therein.

[0025] For example, the molar ratio of the titanium-containing compound to the hydroxycarboxylic acid is 1:0.4, 1:0.6, 1:0.8, 1:1, 1:1.2, 1:1.4, 1:1.6, 1:1.8, 1:2.0, 1:2.2, 1:2.4, 1:2.6, 1:2.8, 1:3.0, or 1:4.0, wherein the molar amount of the hydroxycarboxylic acid is the sum of the molar amounts of the hydroxyl and carboxyl groups, and the molar amount of the titanium-containing compound is the molar amount of titanium.

[0026] In a preferred embodiment, the solvent is selected from alcohol solvents.

[0027] In a further preferred embodiment, the solvent is selected from diols, preferably from at least one of ethylene glycol, propylene glycol and butanediol.

[0028] Preferably, an alcohol solvent that is the same as the diol monomer used in the subsequent polyester production is used as the solvent.

[0029] In a further preferred embodiment, when a solvent is used, the weight ratio of the solvent to titanium in the titanium-containing compound is (4-32):1, preferably (10-20):1.

[0030] For example, the weight ratio of the solvent to titanium in the titanium-containing compound is 5:1, 10:1, 15:1, 20:1, or 25:1.

[0031] In a preferred embodiment, the catalyst optionally contains water.

[0032] In a further preferred embodiment, the titanium content in the titanium-based catalyst is 0.1–10 wt%.

[0033] For example, the titanium content in the titanium-based catalyst is 0.1 wt%, 0.5 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, or 10 wt%.

[0034] A second objective of this invention is to provide a method for preparing a titanium-based catalyst, preferably used to prepare the titanium-based catalyst described in one objective of this invention. The method includes: mixing raw materials including the titanium-containing compound, the monocarboxylic acid, the hydroxycarboxylic acid, and optionally the solvent, and reacting them to obtain the titanium-based catalyst.

[0035] In a preferred embodiment, the titanium compound is a compound having the general formula Ti(OR)4, wherein R is selected from C1 to C2. 10 Straight-chain alkyl groups, C1-C 10 Branched alkyl groups or C1-C 10 Aryl groups.

[0036] In a further preferred embodiment, the titanium compound is a compound having the general formula Ti(OR)4, wherein R is selected from C1-C6 straight-chain alkyl or C1-C6 branched alkyl, such as butyl or isopropyl.

[0037] In a further preferred embodiment, the titanium compound is selected from at least one of tetraethyl titanate, tetrabutyl titanate, and tetraisopropyl titanate.

[0038] In a preferred embodiment, the monocarboxylic acid is a compound containing a carboxyl group and / or a sulfonic acid group.

[0039] In a further preferred embodiment, the monocarboxylic acid is selected from aliphatic organic acids containing a carboxyl group and / or a sulfonic acid group and / or aromatic organic acids containing a carboxyl group and / or a sulfonic acid group.

[0040] In a further preferred embodiment, the monocarboxylic acid is selected from C1-C6 groups containing a carboxyl group and / or a sulfonic acid group. 18 Straight-chain or branched organic acids (preferably C1-C4 straight-chain or branched organic acids), and C6-C20 aromatic organic acids containing a carboxyl group and / or a sulfonic acid group.

[0041] Most preferably, the monocarboxylic acid does not contain hydroxyl groups at the α and / or β positions, and more preferably, the monocarboxylic acid does not contain hydroxyl groups.

[0042] For example, the monocarboxylic acid is selected from at least one of acetic acid, propionic acid, butyric acid, formic acid, etc.

[0043] In a preferred embodiment, the molar ratio of the titanium compound to the monocarboxylic acid is 1:(0.2-5.0), preferably 1:(0.5-2.0), more preferably 1:(1.0-2.0), for example 1:(1.5-2.0), wherein the molar amount of the titanium compound is expressed as the molar amount of titanium element therein, and the molar amount of the monocarboxylic acid is expressed as the molar amount of molecules.

[0044] In a preferred embodiment, the hydroxycarboxylic acid is an organic acid containing one or more hydroxyl groups, preferably an organic acid containing 1 to 3 hydroxyl groups, such as an organic acid containing 1 or 2 hydroxyl groups.

[0045] In a further preferred embodiment, the hydroxycarboxylic acid is selected from at least one of citric acid, lactic acid, malic acid, tartaric acid, 2-hydroxyglutaric acid, 2-hydroxybutyric acid, glycolic acid, mandelic acid, and salicylic acid.

[0046] In a further preferred embodiment, the hydroxyl group in the hydroxycarboxylic acid is located at the α and / or β position of the hydroxycarboxylic acid.

[0047] Hydroxycarboxylic acids are a class of substances commonly used to modify titanium-based catalysts. They are inexpensive and readily available, and their chelation with titanium atoms can effectively inhibit the hydrolysis of titanate esters.

[0048] In a preferred embodiment, the molar ratio of the titanium compound to the hydroxycarboxylic acid is 1:(0.4-4.0), preferably 1:(1.2-4.0), wherein the molar amount of the hydroxycarboxylic acid is the sum of the molar amounts of hydroxyl and carboxyl groups, and the molar amount of the titanium compound is the molar amount of titanium element therein.

[0049] In a preferred embodiment, the solvent is selected from alcohol solvents.

[0050] In a further preferred embodiment, the solvent is selected from diols, including at least one selected from diols such as ethylene glycol, propylene glycol, and butanediol.

[0051] Preferably, an alcohol solvent that is the same as the diol monomer used in the subsequent polyester production is used as the solvent.

[0052] In a preferred embodiment, the reaction temperature is 30-200°C, and / or the reaction time is 0.2-24 h.

[0053] For example, the reaction temperature is 30°C, 50°C, 80°C, 100°C, 120°C, 150°C, 180°C, or 200°C, and / or the reaction time is 0.2h, 0.5h, 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h, 13h, 14h, 15h, 16h, 17h, 18h, 20h, 22h, or 24h.

[0054] In a further preferred embodiment, the reaction temperature is 50–100°C, and / or the reaction time is 1–10 h.

[0055] In a preferred embodiment, the preparation method includes:

[0056] (1) The raw materials, including the titanium-containing compound, the monobasic acid and optionally the solvent, are mixed and reacted;

[0057] (2) Add the mixture of the hydroxycarboxylic acid and the solvent or the hydroxycarboxylic acid to the reaction system of step (1) and carry out the reaction;

[0058] (3) After the reaction in step (2) is completed, post-processing is performed to obtain the titanium catalyst.

[0059] In a preferred embodiment, in step (1), the titanium-containing compound is first mixed with the solvent (optionally), and then the monobasic acid is added (preferably dropwise).

[0060] In a preferred embodiment, in step (2), a mixture of the hydroxycarboxylic acid and the solvent or the hydroxycarboxylic acid is added dropwise to the reaction system of step (1).

[0061] The purpose of adding the dropwise agent is to prevent excessively high local concentrations, which could lead to the formation of large particles and disrupt the preparation process.

[0062] In a further preferred embodiment, the hydroxycarboxylic acid in the mixture with the solvent has a weight concentration of 1 to 50 wt%, preferably 5 to 40 wt%, and more preferably 10 to 30 wt%.

[0063] For example, in the mixture of the hydroxycarboxylic acid and the solvent, the weight concentration of the hydroxycarboxylic acid is 1 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, or 50 wt%.

[0064] In a preferred embodiment, when the solvent is used, the total weight of the solvent used in steps (1) and (2) is in the weight ratio of titanium in the titanium-containing compound to (4-40):1, preferably (10-30):1.

[0065] For example, the weight ratio of the solvent to titanium in the titanium-containing compound is 5:1, 10:1, 15:1, 20:1, 25:1, or 30:1.

[0066] In a further preferred embodiment, the weight ratio of the solvent in step (1) to the titanium in the titanium-containing compound is (2-15):1, preferably (5-10):1; and / or, the weight ratio of the solvent in step (2) to the titanium in the titanium-containing compound is (2-15):1, preferably (5-10):1.

[0067] For example, the weight ratio of the solvent in step (1) to the titanium in the titanium-containing compound is 2:1, 5:1, 8:1, 10:1, 12:1 or 15:1; and / or, the weight ratio of the solvent in step (2) to the titanium in the titanium-containing compound is 2:1, 5:1, 8:1, 10:1, 12:1 or 15:1.

[0068] In a preferred embodiment, in steps (1) and (2), the temperature of the reaction is independently 30-200°C, and / or the reaction time is independently 0.2-24h.

[0069] In a further preferred embodiment, in steps (1) and (2), the temperature of the reaction is independently 50 to 100°C, and / or the reaction time is independently 1 to 10 h.

[0070] For example, the temperature of the reaction is independently 50°C, 60°C, 70°C, 80°C, 90°C or 100°C, and / or the reaction time is independently 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h or 10h.

[0071] In a preferred embodiment, in step (3), the post-processing includes the removal of small molecule compounds and optional dilution.

[0072] In a further preferred embodiment, small molecule compounds are removed by vacuum removal; and / or, the mixture is diluted with water and / or the solvent, preferably to 0.1 to 10 wt%.

[0073] Preferably, the titanium-based catalyst obtained by the present invention is a clear and homogeneous solution. For example, the titanium content in the titanium-based catalyst is controlled to be 0.1 wt%, 0.5 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, or 10 wt%.

[0074] A third objective of this invention is to provide a titanium-based polymer obtained using the preparation method described in the second objective of this invention.

[0075] The fourth objective of this invention is the application of the titanium-based catalyst described in the first objective of this invention or the titanium-based catalyst obtained by the preparation method described in the second objective of this invention in polyester synthesis, especially in the synthesis of PBAT polyester or PBT polyester.

[0076] The titanium-based catalyst can be used for polycondensation reactions of polyols (such as diols) and polyacids (such as diacids), especially for polycondensation reactions of terephthalic acid (PTA) and butanediol (BDO) or terephthalic acid (PTA), adipic acid (AA) and butanediol (BDO).

[0077] In a preferred embodiment, the amount of catalyst used is 50 to 200 ppm, preferably 70 to 150 ppm, based on the weight of the polyester, wherein the amount of catalyst is based on the weight of titanium, and the weight of the polyester refers to the theoretical yield at the current amounts of dicarboxylic acid and diol.

[0078] For example, the amount of catalyst used is 50 ppm, 80 ppm, 100 ppm, 120 ppm, 150 ppm, 180 ppm or 200 ppm, based on the weight of the polyester.

[0079] The application of the above technical solutions is not particularly limited. Those skilled in the art can apply them according to existing process technology conditions, such as, but not limited to, the application of the catalyst composition in the preparation of PBAT and PBT.

[0080] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values; these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. In the following, various technical solutions can, in principle, be combined with each other to obtain new technical solutions, which should also be considered as specifically disclosed herein.

[0081] Compared with the prior art, the present invention has the following beneficial effects:

[0082] (1) The catalyst described in this invention has excellent hydrolysis resistance and high catalytic activity;

[0083] (2) The catalyst described in this invention is simple to prepare and suitable for industrial production;

[0084] (3) The polyester obtained using the catalyst described in this invention has high intrinsic viscosity and excellent hue (characterized by a large L value, a low a value and a low b value). Detailed Implementation

[0085] 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.

[0086] It should also be noted that the various specific technical features described in the following embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the various possible combinations will not be described separately in this invention.

[0087] Furthermore, various embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention. The resulting technical solutions are part of the original disclosure of this specification and also fall within the protection scope of the present invention.

[0088] Unless otherwise specified, the raw materials used in the examples and comparative examples 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.

[0089] In this invention, the intrinsic viscosity, hue, etc. of the polyester are tested using the following methods:

[0090] (1) Intrinsic viscosity: Phenol-tetrachloroethane mixture was used as solvent and measured with an Ubbelohde viscometer at 25°C.

[0091] (2) Hue: After the granular samples were treated at 80℃ or 120℃ for 1 hour, their Hunter L value (brightness), a value (red-green hue), and b value (yellow-blue hue) were measured using a BYK Gardner Color-View automatic colorimeter. A higher L value indicates greater brightness; a higher a value indicates a redder chip; and a higher b value indicates a more yellowish polyester chip. For this invention, the desired outcome is a high L value, a low a value, and a low b value.

[0092]

Example 1

[0093] 170 g (0.5 mol) of tetrabutyl titanate and 200 g of butanediol were added to a three-necked flask equipped with a stirrer, condenser, and thermometer. After stirring until homogeneous, 30 g of acetic acid was added dropwise to the solution. After the addition was complete, the mixture was heated to 70 °C and reacted for 2 hours. Then, 240 g of a 20 wt% citric acid / butanediol solution was added dropwise to the solution. After the addition was complete, the reaction was continued for another 2 hours. Small molecule compounds were then removed by vacuum extraction, and the mixture was further diluted with an appropriate amount of water to obtain a homogeneous catalyst liquid with a titanium concentration of 2 wt%.

[0094] 230g of terephthalic acid, 200g of adipic acid, 400g of butanediol, and the aforementioned catalyst (based on the amount of polyester produced, the weight of titanium atoms is 100ppm) were mixed to form a slurry, which was then added to a polymerization reactor for esterification. The esterification temperature was 190-230℃, and the pressure was atmospheric pressure. The water generated during the reaction was discharged through a distillation device. After esterification, the pressure was reduced to atmospheric pressure, and triphenyl phosphate (based on the amount of polyester produced, the weight of P atoms is 50ppm) was added. The system pressure was then reduced to below 130Pa under vacuum, while the temperature was gradually increased to 240-250℃. The reaction was stopped after 150 minutes. The product was then extruded from the bottom of the polymerization reactor, cooled, and pelletized for performance testing.

[0095] The test results are listed in Table 1.

[0096]

Example 2

[0097] 170 g (0.5 mol) of tetrabutyl titanate and 200 g of butanediol were added to a three-necked flask equipped with a stirrer, condenser, and thermometer. After stirring until homogeneous, 30 g of acetic acid was added dropwise to the solution. After the addition was complete, the mixture was heated to 70 °C and reacted for 2 hours. Then, 480 g of a 20 wt% citric acid / butanediol solution was added dropwise to the solution. After the addition was complete, the reaction was continued for another 2 hours. Small molecule compounds were then removed by vacuum extraction, and the mixture was further diluted with an appropriate amount of water to obtain a homogeneous catalyst liquid with a titanium concentration of 2 wt%.

[0098] 230g of terephthalic acid, 200g of adipic acid, 400g of butanediol, and the aforementioned catalyst (based on the amount of polyester produced, the weight of titanium atoms is 100ppm) were mixed to form a slurry, which was then added to a polymerization reactor for esterification. The esterification temperature was 190-230℃, and the pressure was atmospheric pressure. The water generated during the reaction was discharged through a distillation device. After esterification, the pressure was reduced to atmospheric pressure, and triphenyl phosphate (based on the amount of polyester produced, the weight of P atoms is 50ppm) was added. The system pressure was then reduced to below 130Pa under vacuum, while the temperature was gradually increased to 240-250℃. The reaction was stopped after 150 minutes. The product was then extruded from the bottom of the polymerization reactor, cooled, and pelletized for performance testing.

[0099] The test results are listed in Table 1.

[0100]

Example 3

[0101] 170 g (0.5 mol) of tetrabutyl titanate and 200 g of butanediol were added to a three-necked flask equipped with a stirrer, condenser, and thermometer. After stirring until homogeneous, 30 g of acetic acid was added dropwise to the solution. After the addition was complete, the mixture was heated to 70 °C and reacted for 2 hours. Then, 338 g of a 20 wt% lactic acid / butanediol solution was added dropwise to the solution. After the addition was complete, the reaction was continued for another 2 hours. Small molecule compounds were then removed by vacuum extraction, and the mixture was further diluted with an appropriate amount of water to obtain a homogeneous catalyst liquid with a titanium concentration of 2 wt%.

[0102] 230g of terephthalic acid, 200g of adipic acid, 400g of butanediol, and the aforementioned catalyst (based on the amount of polyester produced, the weight of titanium atoms is 100ppm) were mixed to form a slurry, which was then added to a polymerization reactor for esterification. The esterification temperature was 190-230℃, and the pressure was atmospheric pressure. The water generated during the reaction was discharged through a distillation device. After esterification, the pressure was reduced to atmospheric pressure, and triphenyl phosphate (based on the amount of polyester produced, the weight of P atoms is 50ppm) was added. The system pressure was then reduced to below 130Pa under vacuum, while the temperature was gradually increased to 240-250℃. The reaction was stopped after 150 minutes. The product was then extruded from the bottom of the polymerization reactor, cooled, and pelletized for performance testing.

[0103] The test results are listed in Table 1.

[0104]

Example 4

[0105] 170 g (0.5 mol) of tetrabutyl titanate and 200 g of butanediol were added to a three-necked flask equipped with a stirrer, condenser, and thermometer. After stirring until homogeneous, 30 g of acetic acid was added dropwise to the solution. After the addition was complete, the mixture was heated to 70 °C and reacted for 2 hours. Then, 450 g of a 20 wt% lactic acid / butanediol solution was added dropwise to the solution. After the addition was complete, the reaction was continued for another 2 hours. Small molecule compounds were then removed by vacuum extraction, and the mixture was further diluted with an appropriate amount of water to obtain a homogeneous catalyst liquid with a titanium concentration of 2 wt%.

[0106] 230g of terephthalic acid, 200g of adipic acid, 400g of butanediol, and the aforementioned catalyst (based on the amount of polyester produced, the weight of titanium atoms is 100ppm) were mixed to form a slurry, which was then added to a polymerization reactor for esterification. The esterification temperature was 190-230℃, and the pressure was atmospheric pressure. The water generated during the reaction was discharged through a distillation device. After esterification, the pressure was reduced to atmospheric pressure, and triphenyl phosphate (based on the amount of polyester produced, the weight of P atoms is 50ppm) was added. The system pressure was then reduced to below 130Pa under vacuum, while the temperature was gradually increased to 240-250℃. The reaction was stopped after 150 minutes. The product was then extruded from the bottom of the polymerization reactor, cooled, and pelletized for performance testing.

[0107] The test results are listed in Table 1.

[0108]

Example 5

[0109] 170 g (0.5 mol) of tetrabutyl titanate and 200 g of butanediol were added to a three-necked flask equipped with a stirrer, condenser, and thermometer. After stirring until homogeneous, 30 g of acetic acid was added dropwise to the solution. After the addition was complete, the mixture was heated to 70 °C and reacted for 2 hours. Then, 380 g of a 20 wt% glycolic acid / butanediol solution was added dropwise to the solution. After the addition was complete, the reaction was continued for another 2 hours. Small molecule compounds were then removed by vacuum extraction, and the mixture was further diluted with an appropriate amount of water to obtain a homogeneous catalyst liquid with a titanium concentration of 2 wt%.

[0110] 230g of terephthalic acid, 200g of adipic acid, 400g of butanediol, and the aforementioned catalyst (based on the amount of polyester produced, the weight of titanium atoms is 100ppm) were mixed to form a slurry, which was then added to a polymerization reactor for esterification. The esterification temperature was 190-230℃, and the pressure was atmospheric pressure. The water generated during the reaction was discharged through a distillation device. After esterification, the pressure was reduced to atmospheric pressure, and triphenyl phosphate (based on the amount of polyester produced, the weight of P atoms is 50ppm) was added. The system pressure was then reduced to below 130Pa under vacuum, while the temperature was gradually increased to 240-250℃. The reaction was stopped after 150 minutes. The product was then extruded from the bottom of the polymerization reactor, cooled, and pelletized for performance testing.

[0111] The test results are listed in Table 1.

[0112]

Example 6

[0113] The catalyst was prepared in the same manner as in Example 2.

[0114] 450g of terephthalic acid, 400g of butanediol, and the aforementioned catalyst (based on the amount of polyester produced, the weight of titanium atoms is 100ppm) were mixed to form a slurry, which was then added to a polymerization reactor for esterification. The esterification temperature was 210-230℃, and the pressure was atmospheric pressure. The water generated during the reaction was discharged through a distillation device. After esterification, the pressure was reduced to atmospheric pressure, and then vacuumed until the system pressure was below 130Pa. Simultaneously, the temperature was gradually increased to 240-250℃. The reaction was stopped after 150 minutes. The product was then extruded from the bottom of the polymerization reactor, cooled, and pelletized for performance testing.

[0115] The test results are listed in Table 1.

[0116]

Example 7

[0117] The catalyst was prepared in the same manner as in Example 4.

[0118] 450g of terephthalic acid, 400g of butanediol, and the aforementioned catalyst (based on the amount of polyester produced, the weight of titanium atoms is 100ppm) were mixed to form a slurry, which was then added to a polymerization reactor for esterification. The esterification temperature was 210-230℃, and the pressure was atmospheric pressure. The water generated during the reaction was discharged through a distillation device. After esterification, the pressure was reduced to atmospheric pressure, and then vacuumed until the system pressure was below 130Pa. Simultaneously, the temperature was gradually increased to 240-250℃. The reaction was stopped after 150 minutes. The product was then extruded from the bottom of the polymerization reactor, cooled, and pelletized for performance testing.

[0119] The test results are listed in Table 1.

[0120]

Example 8

[0121] The catalyst was prepared in the same manner as in Example 5.

[0122] 450g of terephthalic acid, 400g of butanediol, and the aforementioned catalyst (based on the amount of polyester produced, the weight of titanium atoms is 100ppm) were mixed to form a slurry, which was then added to a polymerization reactor for esterification. The esterification temperature was 210-230℃, and the pressure was atmospheric pressure. The water generated during the reaction was discharged through a distillation device. After esterification, the pressure was reduced to atmospheric pressure, and then vacuumed until the system pressure was below 130Pa. Simultaneously, the temperature was gradually increased to 240-250℃. The reaction was stopped after 150 minutes. The product was then extruded from the bottom of the polymerization reactor, cooled, and pelletized for performance testing.

[0123] The test results are listed in Table 1.

[0124]

Example 9

[0125] 170 g (0.5 mol) of tetrabutyl titanate and 240 g of butanediol were added to a three-necked flask equipped with a stirrer, condenser, and thermometer. After stirring until homogeneous, 55.56 g of propionic acid was added dropwise to the solution. After the addition was complete, the mixture was heated to 50 °C and reacted for 5 hours. Then, 152.3 g of a 22 wt% malic acid / butanediol solution was added dropwise to the solution. After the addition was complete, the reaction was continued for another 5 hours. Small molecule compounds were then removed by vacuum extraction, and the mixture was further diluted with an appropriate amount of water to obtain a homogeneous catalyst liquid with a titanium concentration of 1 wt%.

[0126] 230g of terephthalic acid, 200g of adipic acid, 400g of butanediol, and the aforementioned catalyst (based on the amount of polyester produced, the weight of titanium atoms is 70ppm) were mixed to form a slurry, which was then added to a polymerization reactor for esterification. The esterification temperature was 190-230℃, and the pressure was atmospheric pressure. The water generated during the reaction was discharged through a distillation device. After esterification, the pressure was reduced to atmospheric pressure, and triphenyl phosphate (based on the amount of polyester produced, the weight of P atoms is 50ppm) was added. The system pressure was then reduced to below 130Pa under vacuum, while the temperature was gradually increased to 240-250℃. The reaction was stopped after 150 minutes. The product was then extruded from the bottom of the polymerization reactor, cooled, and pelletized for performance testing.

[0127] The test results are listed in Table 1.

[0128]

Example 10

[0129] 170 g (0.5 mol) of tetrabutyl titanate and 120 g of butanediol were added to a three-necked flask equipped with a stirrer, condenser, and thermometer. After stirring until homogeneous, 88.1 g of butyric acid was added dropwise to the solution. After the addition was complete, the mixture was heated to 100 °C and reacted for 1 hour. Then, 287 g of a 16.38 wt% tartaric acid / butanediol solution was added dropwise to the solution. After the addition was complete, the temperature was raised to 100 °C and the reaction was continued for 1 hour. Small molecule compounds were then removed by vacuum extraction, and the mixture was further diluted with an appropriate amount of water to obtain a homogeneous catalyst liquid with a titanium concentration of 5 wt%.

[0130] 230g of terephthalic acid, 200g of adipic acid, 400g of butanediol, and the aforementioned catalyst (based on the amount of polyester produced, the weight of titanium atoms is 150ppm) were mixed to form a slurry, which was then added to a polymerization reactor for esterification. The esterification temperature was 190-230℃, and the pressure was atmospheric pressure. The water generated during the reaction was discharged through a distillation device. After esterification, the pressure was reduced to atmospheric pressure, and triphenyl phosphate (based on the amount of polyester produced, the weight of P atoms is 50ppm) was added. The system pressure was then reduced to below 130Pa under vacuum, while the temperature was gradually increased to 240-250℃. The reaction was stopped after 150 minutes. The product was then extruded from the bottom of the polymerization reactor, cooled, and pelletized for performance testing.

[0131] The test results are listed in Table 1.

[0132] Comparative Example 1

[0133] 170 g (0.5 mol) of tetrabutyl titanate and 200 g of butanediol were added to a three-necked flask equipped with a stirrer, condenser, and thermometer. After stirring until homogeneous, 240 g of a 20 wt% citric acid / butanediol solution was added dropwise. After the addition was complete, the reaction was continued for 2 hours. Small molecule compounds were then removed by vacuum extraction, and the solution was further diluted with an appropriate amount of butanediol to obtain a homogeneous catalyst liquid with a titanium concentration of 2 wt%.

[0134] 230g of terephthalic acid, 200g of adipic acid, 400g of butanediol, and the aforementioned catalyst (based on the amount of polyester produced, the weight of titanium atoms is 100ppm) were mixed to form a slurry, which was then added to a polymerization reactor for esterification. The esterification temperature was 190-230℃, and the pressure was atmospheric pressure. The water generated during the reaction was discharged through a distillation device. After esterification, the pressure was reduced to atmospheric pressure, and triphenyl phosphate (based on the amount of polyester produced, the weight of P atoms is 50ppm) was added. The system pressure was then reduced to below 130Pa under vacuum, while the temperature was gradually increased to 240-250℃. The reaction was stopped after 150 minutes. The product was then extruded from the bottom of the polymerization reactor, cooled, and pelletized for performance testing.

[0135] The test results are listed in Table 1.

[0136] Comparative Example 2

[0137] 170 g (0.5 mol) of tetrabutyl titanate and 200 g of butanediol were added to a three-necked flask equipped with a stirrer, condenser, and thermometer. After stirring until homogeneous, 720 g of a 20 wt% citric acid / butanediol solution was added dropwise. After the addition was complete, the reaction was continued for 2 hours. Small molecule compounds were then removed by vacuum extraction, and the solution was further diluted with an appropriate amount of water to obtain a homogeneous catalyst liquid with a titanium concentration of 2 wt%.

[0138] 230g of terephthalic acid, 200g of adipic acid, 400g of butanediol, and the aforementioned catalyst (based on the amount of polyester produced, the weight of titanium atoms is 100ppm) were mixed to form a slurry, which was then added to a polymerization reactor for esterification. The esterification temperature was 190-230℃, and the pressure was atmospheric pressure. The water generated during the reaction was discharged through a distillation device. After esterification, the pressure was reduced to atmospheric pressure, and triphenyl phosphate (based on the amount of polyester produced, the weight of P atoms is 50ppm) was added. The system pressure was then reduced to below 130Pa under vacuum, while the temperature was gradually increased to 240-250℃. The reaction was stopped after 150 minutes. The product was then extruded from the bottom of the polymerization reactor, cooled, and pelletized for performance testing.

[0139] The test results are listed in Table 1.

[0140] Comparative Example 3

[0141] 230g of terephthalic acid, 200g of adipic acid, 400g of butanediol, and n-butyl titanate (based on the amount of polyester produced, the weight of titanium atoms is 100ppm) were mixed to form a slurry, which was then added to a polymerization reactor for esterification. The esterification temperature was 190-230℃, and the pressure was atmospheric pressure. The water generated in the reaction was discharged through a distillation device. After esterification, the pressure was reduced to atmospheric pressure, and triphenyl phosphate (based on the amount of polyester produced, the weight of P atoms is 50ppm) was added. The system pressure was then reduced to below 130Pa under vacuum, while the temperature was gradually increased to 240-250℃. The reaction was stopped after 150 minutes. The product was then extruded from the bottom of the polymerization reactor, cooled, and pelletized for performance testing.

[0142] The test results are listed in Table 1.

[0143]

Experimental Example

[0144] The catalysts obtained in Examples 1-5 and Comparative Examples 1-3 were poured into hot water at >95°C, and the solution was observed. If there was no change, it indicated good hydrolysis resistance. The results are listed in Table 1.

[0145] Table 1:

[0146]

[0147] As can be seen from Table 1:

[0148] (1) The catalysts obtained in Examples 1 to 5 remained clear and transparent when placed in hot water, indicating that they had excellent hydrolysis resistance; while the catalysts obtained in Comparative Examples 1 and 3 turned into white turbidity when placed in hot water, indicating that they had poor hydrolysis resistance.

[0149] (2) Comparing Example 1 with Comparative Examples 1 to 3, the intrinsic viscosity of the polyester obtained in Example 1 is significantly higher than that in Comparative Examples 1 to 3, indicating that the activity of the catalyst used in Example 1 is significantly higher than that of the catalyst used in Comparative Examples 1 to 3.

[0150] (3) Comparing Example 1 with Comparative Examples 1 to 3, the polyester obtained in Example 1 has a better hue (mainly manifested by a higher L value, a lower a value (in absolute value) and a lower b value).

[0151] Here, the value of a represents the blue and red color of polyester. The value of a can be negative or positive. The more negative the value, the bluer it is, and the more positive the value, the redder it is. The present invention aims for an absolute value of a < 2, which means that the polyester is neither red nor blue and is close to colorless.

[0152] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

Claims

1. A titanium-based catalyst comprising the reaction product of: (1) a titanium-containing compound, (2) a monoprotic acid, (3) a hydroxycarboxylic acid, (4) optionally a solvent; wherein, (1) mixing raw materials including the titanium-containing compound, the monobasic acid, and optionally the solvent, and performing a reaction; (2) adding a mixture of the hydroxyl carboxylic acid and the solvent or the hydroxyl carboxylic acid to the reaction system of step (1), and performing a reaction; (3) performing post-treatment after the reaction of step (2) is completed to obtain the titanium-based catalyst; in steps (1) and (2), the temperature of the reaction is independently 50 to 200°C.

2. The titanium-based catalyst according to claim 1, characterized in that, The titanium-containing compound is a compound having the general formula Ti(OR)4, wherein R is selected from a linear alkyl group of C1-C 10 , a branched alkyl group of C1-C 10 , or an aryl group of C1-C 10 .

3. The titanium-based catalyst according to claim 1, characterized in that, The titanium-containing compound is a compound having a general formula of Ti(OR)4, wherein R is selected from a linear alkyl group having 1 to 6 carbon atoms or a branched alkyl group having 1 to 6 carbon atoms.

4. The titanium-based catalyst according to claim 1, characterized in that, The monobasic acid is a compound containing one carboxyl group and / or one sulfonic acid group.

5. The titanium-based catalyst according to claim 1, wherein The monobasic acid is selected from at least one of an aliphatic organic acid containing one carboxyl group and / or one sulfonic acid group and an aromatic organic acid containing one carboxyl group and / or one sulfonic acid group.

6. The titanium-based catalyst according to claim 1, wherein The molar ratio of the titanium-containing compound to the monobasic acid is 1: (0.2 to 5.0), wherein the molar amount of the titanium-containing compound is based on the molar amount of titanium element, and the molar amount of the monobasic acid is based on the molar amount of the molecule.

7. The titanium-based catalyst according to claim 1, wherein The molar ratio of the titanium-containing compound to the monobasic acid is 1: (0.5 to 2.0), wherein the molar amount of the titanium-containing compound is based on the molar amount of titanium element, and the molar amount of the monobasic acid is based on the molar amount of the molecule.

8. The titanium-based catalyst according to claim 1, wherein The hydroxyl carboxylic acid is an organic acid containing one or more hydroxyl groups.

9. The titanium-based catalyst according to claim 1, wherein The hydroxyl carboxylic acid is an organic acid containing 1 to 3 hydroxyl groups.

10. The titanium-based catalyst according to claim 1, wherein The hydroxyl carboxylic acid is selected from at least one of citric acid, lactic acid, malic acid, tartaric acid, 2-hydroxyglutaric acid, 2-hydroxybutyric acid, glycolic acid, mandelic acid, and salicylic acid.

11. The titanium-based catalyst according to claim 1, characterized in that, The molar ratio of the titanium-containing compound to the hydroxyl carboxylic acid is 1: (0.4 to 4.0), wherein the molar amount of the hydroxyl carboxylic acid is based on the total molar amount of the hydroxyl group and the carboxyl group, and the molar amount of the titanium-containing compound is based on the molar amount of titanium element.

12. The titanium-based catalyst according to claim 1, characterized in that, The molar ratio of the titanium-containing compound to the hydroxyl carboxylic acid is 1: (1.2 to 4.0), wherein the molar amount of the hydroxyl carboxylic acid is based on the total molar amount of the hydroxyl group and the carboxyl group, and the molar amount of the titanium-containing compound is based on the molar amount of titanium element.

13. The titanium-based catalyst according to any one of claims 1 to 12, characterized in that, The solvent is selected from an alcohol solvent.

14. The titanium-based catalyst according to claim 13, characterized in that, The solvent is selected from a dihydric alcohol.

15. The titanium-based catalyst according to claim 13, wherein The titanium-based catalyst contains water.

16. The titanium-based catalyst of claim 13, wherein, The titanium content of the titanium-based catalyst is 0.1 to 10 wt%.

17. A method for producing a titanium-based catalyst, the method being for producing the titanium-based catalyst according to any one of claims 1 to 16, the method comprising: (1) mixing raw materials including the titanium-containing compound, the monobasic acid, and optionally the solvent, and performing a reaction; (2) adding a mixture of the hydroxyl carboxylic acid and the solvent or the hydroxyl carboxylic acid to the reaction system of step (1), and performing a reaction; (3) performing post-treatment after the reaction of step (2) is completed to obtain the titanium-based catalyst; in steps (1) and (2), the temperature of the reaction is independently 50 to 200°C.

18. The production method according to claim 17, wherein, in step (1), the titanium-containing compound is first mixed with the optional solvent, and then the monobasic acid is added thereto; and / or, in step (2), the hydroxyl carboxylic acid is first mixed with the solvent, and then the mixture is added to the reaction system of step (1). ​ In step (2), a mixture of the hydroxyl carboxylic acid and the solvent or the hydroxyl carboxylic acid is added dropwise to the reaction system of step (1).

19. The preparation method according to claim 17, characterized in that, In the mixture of the hydroxyl carboxylic acid and the solvent, the weight concentration of the hydroxyl carboxylic acid is 1-50 wt%.

20. The production method according to claim 17, wherein, the total weight of the solvent used in step (1) and step (2) to the weight of titanium in the titanium-containing compound is (4-32): 1; and / or, the weight of the solvent used in step (1) to the weight of titanium in the titanium-containing compound is (2-15): 1; and / or, the weight of the solvent used in step (2) to the weight of titanium in the titanium-containing compound is (2-15):

1.

21. The production method according to claim 17, wherein, the total weight of the solvent used in step (1) and step (2) to the weight of titanium in the titanium-containing compound is (10-20): 1; and / or, the weight of the solvent used in step (1) to the weight of titanium in the titanium-containing compound is (5-10): 1; and / or, the weight of the solvent used in step (2) to the weight of titanium in the titanium-containing compound is (5-10):

1.

22. The production method according to any one of claims 17-21, wherein, in step (1) and step (2), the reaction time is independently 0.2-24 h; and / or, in step (3), the post-treatment includes removing small molecular compounds and optional dilution treatment.

23. The production method according to any one of claims 17-21, wherein, in step (1) and step (2), the reaction temperature is independently 50-100°C, and / or the reaction time is independently 1-10 h.

24. A titanium-based catalyst obtained by the production method according to any one of claims 17-23.

25. Use of the titanium-based catalyst according to any one of claims 1-16 or the titanium-based catalyst obtained by the production method according to any one of claims 17-23 in polyester synthesis. Use in PBAT polyester or PBT polyester synthesis.

26. The use according to claim 25, characterized in that, ​

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