Titanium-containing composition, preparation method thereof and polyester catalyst

Abstract

The invention discloses a titanium-containing composition, a preparation method thereof and a polyester catalyst, and relates to the technical field of polyester catalysts, and the titanium-containing composition comprises reaction products of the following components: a titanium compound, a solvent, hydroxycarboxylic acid and / or amino acid. The titanium-containing composition is obtained by mixing and reacting the titanium compound, the solvent, the hydroxycarboxylic acid and / or the amino acid, the solvent adopts ethylene glycol ester, the flash point is high, the reaction activity with titanium is low, the preparation process is very smooth, meanwhile, the performance change of polyester is not caused when the titanium-containing composition is used for polyester, and the technical effect is good.

Description

Technical Field

[0001] This invention relates to the field of catalysts for polyesters, and more specifically, to a titanium-containing composition, a method for preparing the same, and a polyester catalyst. Background Technology

[0002] In the preparation of polyesters, including polyethylene terephthalate (PET) and polyethylene furanate, common catalysts include antimony-based catalysts such as antimony glycolate and antimony acetate, and titanium-based catalysts such as tetraisopropyl titanate and n-butyl titanate. Antimony-based catalysts are characterized by high activity and good quality polyesters, but because antimony is a heavy metal, it poses environmental and human health risks and is therefore restricted by governments worldwide. For example, Japan restricts the use of antimony-based catalysts in hot-filled PET bottles.

[0003] Titanium-based catalysts, primarily composed of titanate esters, are non-toxic and highly active, but they are prone to hydrolysis and precipitation during use, causing problems. Currently, a common method for hydrolysis resistance treatment is to add hydroxycarboxylic acids to titanate esters to improve their hydrolysis stability. Chinese patent CN105121500A discloses a method for preparing a hydrolysis-resistant titanium-containing composition by adding titanate esters dropwise to an aqueous citric acid solution. However, the addition of a large amount of water inevitably results in the presence of some solid titanium hydrolysate precipitates, leading to the loss of titanium compounds. Furthermore, the presence of water necessitates the addition of a high proportion of citric acid to facilitate the successful preparation of the titanium-containing composition; insufficient acid concentration fails to yield a stable and clear titanium-containing composition, while excessive acid is economically undesirable and detrimental to polyester quality. Chinese patent CN102382287A discloses the preparation of a titanium-containing composition by mixing citric acid monohydrate with titanate esters in a monohydric alcohol solvent such as ethanol or isopropanol, with the monohydric alcohol removed in the later stages of preparation. This method reduces the water content, resulting in a smoother preparation process. However, the large-scale use of monohydric alcohols makes it economically undesirable, and the residual monohydric alcohols may lower the flash point of the titanium-containing composition, increasing the safety risks of storage and transportation. The literature J.Am.Ceram.Soc.,85

[12] 2984–88 (2002) discloses the preparation of titanium-containing compositions by mixing ethylene glycol, citric acid and titanate, wherein ethylene glycol is the raw material for preparing polyester, and ethylene glycol has a high flash point, which has good advantages in terms of economy and safety. However, this process cannot obtain a clear and transparent titanium composition solution. Chinese patent CN112708120A mentions the preparation of titanium-containing compositions by using diethylene glycol, citric acid and titanate in the examples. Although the preparation process is smooth and diethylene glycol has a high flash point, its use will cause diethylene glycol to enter the polyester main chain when the titanium-containing composition is used to prepare polyester PET, resulting in a decrease in the melting point of polyester. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a titanium-containing composition, its preparation method, and a polyester catalyst. The titanium-containing composition of this invention is obtained by mixing and reacting a titanium compound, a solvent, a hydroxycarboxylic acid, and / or an amino acid. The solvent used is an ethylene glycol ester with a high flash point and low reactivity with titanium, making the preparation process very smooth. Furthermore, when used in polyesters, it does not cause changes in the polyester properties, thus exhibiting good technical advantages.

[0005] One of the objectives of this invention is to provide a titanium-containing composition.

[0006] The present invention discloses a titanium-containing composition comprising the reaction product of the following components: titanium compound, solvent, hydroxycarboxylic acid and / or amino acid.

[0007] In a preferred embodiment of the present invention:

[0008] The molar ratio of titanium element in the titanium compound to the total molar ratio of hydroxyl and carboxyl groups in the hydroxycarboxylic acid is 1:(0.4-10.0), preferably 1:(2.0-8.0), and / or, the molar ratio of titanium element in the titanium compound to the total molar ratio of amino and carboxyl groups in the amino acid is 1:(0.4-10.0), preferably 1:(2.0-8.0); when the amount of hydroxyl and carboxyl groups in the hydroxycarboxylic acid and / or the amount of amino and carboxyl groups in the amino acid is below the lower limit, the prepared titanium-containing composition does not have hydrolysis resistance as a catalyst; when it is above the upper limit, the raw material is in excess; and / or,

[0009] Based on a total weight of 100 wt% of the titanium compound, solvent, hydroxycarboxylic acid, and / or amino acid, the titanium element in the titanium compound is 0.01-10 wt%, preferably 0.1-8 wt%.

[0010] In a preferred embodiment of the present invention:

[0011] The titanium compound is an organotitanium compound, preferably Ti(OR)4, wherein each R is independently selected from one of C1-C10 straight-chain alkyl, C1-C10 branched alkyl, and C1-C10 aryl, more preferably a C1-C6 straight-chain alkyl or a C1-C6 branched alkyl.

[0012] In a preferred embodiment of the present invention:

[0013] The hydroxycarboxylic acid is α-hydroxycarboxylic acid; preferably, the α-hydroxycarboxylic acid contains 1 to 3 hydroxyl groups; more preferably, the α-hydroxycarboxylic acid is at least one selected from citric acid, lactic acid, malic acid, tartaric acid, 2-hydroxyglutaric acid, 2-hydroxybutyric acid, glycolic acid, and mandelic acid; α-hydroxycarboxylic acid is a class of substances commonly used to modify titanium-based catalysts, characterized by low cost and easy availability. Its chelation with titanium atoms can effectively inhibit the hydrolysis of titanate esters and improve the stability of the catalyst itself; and / or,

[0014] The amino acid is an α-amino acid, preferably at least one of glycine, alanine, valine, leucine, isoleucine, and serine.

[0015] In a preferred embodiment of the present invention:

[0016] The solvent is an ethylene glycol ester, preferably at least one of ethylene glycol monoester, ethylene glycol diester, and ethylene glycol carbonate, more preferably at least one of ethylene glycol monoester containing a C1-C10 straight-chain alkyl group and / or a C1-C10 branched alkyl group, ethylene glycol diester containing a C1-C10 straight-chain alkyl group and / or a C1-C10 branched alkyl group, and ethylene carbonate. The ethylene glycol ester is mainly used to dissolve / dilute hydroxycarboxylic acids and titanates, thereby ensuring the smooth progress of the titanium-containing composition preparation process. Simultaneously, the high flash point of the ethylene glycol ester does not increase the storage and transportation risks of the titanium-containing composition. Furthermore, when the titanium-containing composition is subsequently used in polyester preparation, this compound will hydrolyze to generate ethylene glycol. Since ethylene glycol is a reactant for polyester, its impact on polyester quality is minimal. A suitable carbon chain length ensures that the ethylene glycol ester can be used as an effective solvent and will not participate in the reaction during the preparation of the titanium-containing composition, thus avoiding the problem of ethylene glycol reacting with other raw materials.

[0017] A second objective of this invention is to provide a method for preparing a titanium-containing composition as described in one objective of this invention.

[0018] The method for preparing the titanium-containing composition according to the present invention includes one of the following two methods:

[0019] Method 1: The titanium compound is mixed with a portion of the solvent to obtain mixture 1; the remaining solvent is mixed with the hydroxycarboxylic acid and / or amino acid to obtain mixture 2; mixture 2 is then added to mixture 1 for a heated reaction to obtain the titanium-containing composition; Method 1 of the present invention, by dividing the solvent into two parts and mixing them separately with the titanium compound, hydroxycarboxylic acid and / or amino acid for reaction, can effectively prevent the formation of gel during the reaction of the titanium compound with the hydroxycarboxylic acid and / or amino acid, ensuring the smooth progress of the reaction;

[0020] Method 2: The solvent is mixed with hydroxycarboxylic acid and / or amino acid to obtain a mixture; the titanium compound is added to the mixture and heated to obtain the titanium-containing composition; Method 2 of the present invention, by adding the titanium compound dropwise or in batches to the mixture of solvent and hydroxycarboxylic acid and / or amino acid, also avoids the problem of gelation.

[0021] In a preferred embodiment of the present invention:

[0022] In Method 1:

[0023] The mass ratio of the titanium compound to a portion of the solvent is 1:(0.5-3), preferably 1:(0.5-2; and / or,

[0024] The mass ratio of the remaining solvent to hydroxycarboxylic acid and / or amino acid is (1-9):1, preferably (1-5):1.

[0025] In a preferred embodiment of the present invention:

[0026] In Method 1:

[0027] The mixing temperature of the titanium compound and a portion of the solvent is 0-50°C, preferably 20-50°C; and / or,

[0028] The mixing temperature of the remaining solvent with the hydroxycarboxylic acid and / or amino acid is 0-50°C, preferably 20-50°C; and / or,

[0029] The second mixture is added dropwise or in batches to the first mixture; and / or

[0030] The reaction temperature of the heating reaction is 30-200℃, preferably 50-100℃, and / or the reaction time is 0.2-24h, preferably 1-10h.

[0031] In a preferred embodiment of the present invention:

[0032] In Method Two:

[0033] The mixing temperature of the solvent with the hydroxycarboxylic acid and / or amino acid is 0-50°C, preferably 20-50°C; and / or,

[0034] The titanium compound is added dropwise or in batches to the mixture; and / or,

[0035] The reaction temperature of the heating reaction is 30-200℃, preferably 50-100℃, and / or the reaction time is 0.2-24h, preferably 1-10h.

[0036] A third objective of this invention is to provide a polyester catalyst comprising at least one titanium-containing composition as described in one objective of this invention or a titanium-containing composition prepared by the method described in another objective of this invention.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] The titanium-containing composition obtained by adopting the technical solution of the present invention has a smooth preparation process and avoids the introduction of low flash point compounds such as isopropanol or compounds that require high production equipment (explosion-proof) such as isopropanol, as well as the introduction of compounds that affect the polyester preparation process, thus achieving better technical results.

[0039] The titanium-containing composition prepared by this invention is a clear and transparent solution, i.e., a homogeneous liquid-phase catalyst. When used as a liquid-phase catalyst in the polyester preparation process, compared with the problem of inaccurate measurement when using solid catalysts, the liquid catalyst of this invention is in a homogeneous state, making it more convenient to use.

[0040] The application of the above technical solutions is not particularly limited, and those skilled in the art can apply them according to existing process technology conditions.

[0041] 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. Detailed Implementation

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046]

Example 1

[0047] 142.2 g (0.5 mol) of tetraisopropyl titanate and 150 g of ethylene glycol diacetate were added to a three-necked flask equipped with a stirrer, condenser, and thermometer. After mixing thoroughly, 480 g of a 20 wt% ethylene glycol diacetate solution of citric acid was added dropwise, resulting in a turbid solution. The solution was heated to 80 °C and reacted for 3 hours to obtain a clear and transparent solution. The solution was then cooled to room temperature to obtain a titanium-containing composition with a titanium weight concentration of approximately 3.1 wt%.

[0048]

Example 2

[0049] 142.2 g (0.5 mol) of tetraisopropyl titanate and 150 g of 2-hydroxyethyl acetate (commercially available 60 wt% concentration, with the remaining 40 wt% mainly composed of ethylene glycol diacetate) were added to a three-necked flask equipped with a stirrer, condenser, and thermometer. After mixing, a slightly turbid solution was obtained. 480 g of a 20 wt% citric acid solution in 2-hydroxyethyl acetate was then added dropwise to the above solution, resulting in a turbid solution. The solution was heated to 80 °C and reacted for 3 hours to obtain a clear and transparent solution. The solution was then cooled to room temperature to obtain a titanium-containing composition with a titanium weight concentration of approximately 3.1 wt%.

[0050]

Example 3

[0051] 142.2 g (0.5 mol) of tetraisopropyl titanate and 150 g of ethylene carbonate were added to a three-necked flask equipped with a stirrer, condenser, and thermometer. The mixture was heated to 50 °C to obtain a slightly turbid solution. A molten (melting temperature > 40 °C) 20 wt% ethylene carbonate solution of citric acid was rapidly added in portions to this solution, totaling 480 g, resulting in a turbid solution. The solution was then heated to 80 °C and reacted for 3 hours to obtain a clear and transparent solution. The solution was then cooled to room temperature to obtain a titanium-containing composition with a titanium weight concentration of approximately 3.1 wt%.

[0052]

Example 4

[0053] 170.2 g (0.5 mol) of tetrabutyl titanate and 340.4 g of ethylene glycol diacetate were added to a three-necked flask equipped with a stirrer, condenser, and thermometer. After mixing thoroughly, 360.32 g of a 50 wt% lactic acid solution in ethylene glycol diacetate was added dropwise, resulting in a turbid solution. The solution was heated to 80 °C and reacted for 3 hours to obtain a clear and transparent solution. The solution was then cooled to room temperature to obtain a titanium-containing composition with a titanium weight concentration of approximately 2.8 wt%.

[0054]

Example 5

[0055] 114.06 g (0.5 mol) of tetraethyl titanate and 120 g of ethylene glycol diacetate were added to a three-necked flask equipped with a stirrer, condenser, and thermometer. After mixing thoroughly, 225.43 g of a 33.3 wt% glycine solution in ethylene glycol diacetate was added dropwise, resulting in a turbid solution. The solution was heated to 60 °C and reacted for 2 hours to obtain a clear and transparent solution. The solution was then cooled to room temperature to obtain a titanium-containing composition with a titanium weight concentration of approximately 5.2 wt%.

[0056]

Example 6

[0057] 48 g of citric acid and 109.8 g of ethylene glycol diacetate were added to a three-necked flask equipped with a stirrer, condenser, and thermometer. After mixing thoroughly, 142.2 g (0.5 mol) of tetraisopropyl titanate was added dropwise, resulting in a turbid solution. The solution was heated to 80 °C and reacted for 3 hours to obtain a clear and transparent solution. The solution was then cooled to room temperature to obtain a titanium-containing composition with a titanium weight concentration of approximately 8 wt%.

[0058] Hydrolysis test:

[0059] The titanium-containing compositions obtained in Examples 1-6 were respectively prepared with water and ethylene glycol to form ethylene glycol solutions with a titanium concentration of 1 wt% and a water content of 10 wt%. The solutions were then further heated to 95°C, and the state of the solutions before and after heating was observed.

[0060] The results showed that the mixed solution of the above-mentioned titanium-containing composition with water and ethylene glycol remained clear and transparent both before and after heating. This indicates that the titanium-containing composition prepared in the embodiments of the present invention has hydrolysis resistance and is easy to use.

[0061]

Example 7

[0062] Preparation of polyester:

[0063] 500g of terephthalic acid, 316g of ethylene glycol, the titanium-containing composition prepared in Example 1 as a catalyst (10 ppm titanium by weight), and trimethyl phosphate (5 ppm phosphorus by weight) were mixed to form a slurry, which was then added to a polymerization reactor for esterification. The esterification temperature was 230-250℃ and the pressure was 0.25MPa. The water generated during the reaction was discharged through a distillation apparatus. After esterification, the pressure was reduced to atmospheric pressure and then evacuated until the system pressure was below 130Pa. Simultaneously, the temperature was gradually increased to 280℃. The reaction was stopped after 150 minutes. The product was then extruded from the bottom of the polymerization reactor, cooled, and pelletized to obtain polyester chips.

[0064] Comparative Example 1

[0065] 142.2 g (0.5 mol) of tetraisopropyl titanate was added to a three-necked flask equipped with a stirrer, condenser, and thermometer. 150 g of ethylene glycol was then slowly added dropwise, and after thorough mixing, a white, turbid precipitate was obtained. 480 g of a 20 wt% citric acid solution in ethylene glycol was then added dropwise. When about half of the solution was added, a large gel formed, hindering the preparation process, and the experiment was stopped.

[0066] Comparative Example 2

[0067] 142.2 g (0.5 mol) of tetraisopropyl titanate, 534 g of ethylene glycol diacetate, and 57.6 g of citric acid were added to a three-necked flask equipped with a stirrer, condenser, and thermometer. After mixing thoroughly, a viscous precipitate formed at the bottom where the citric acid was deposited. The precipitate could not be dissolved or dispersed, which hindered the preparation, and the experiment was stopped.

[0068] Comparative Example 3

[0069] 142.2 g (0.5 mol) of tetraisopropyl titanate was added to a three-necked flask equipped with a stirrer, condenser, and thermometer. 150 g of diethylene glycol was then slowly added dropwise, and the mixture was thoroughly stirred to obtain a clear solution. 480 g of a 20 wt% diethylene glycol solution of citric acid was then added dropwise to the above solution, resulting in a turbid solution. The solution was heated to 80 °C and reacted for 1-3 hours to obtain a clear, transparent solution. The solution was then cooled to room temperature to obtain a titanium-containing composition with a titanium weight concentration of approximately 3.1 wt%.

[0070] Comparative Example 4

[0071] Preparation of polyester:

[0072] 500g of terephthalic acid, 316g of ethylene glycol, the titanium-containing composition prepared in Comparative Example 3 (10 ppm titanium by weight) as a catalyst, and trimethyl phosphate (5 ppm phosphorus by weight) were mixed to form a slurry, which was then added to a polymerization reactor for esterification. The esterification temperature was 230-250℃ and the pressure was 0.25MPa. The water generated in the reaction was discharged through a distillation device. After esterification, the pressure was reduced to atmospheric pressure and then evacuated until the system pressure was below 130Pa. At the same time, the temperature was gradually increased to 280℃. The reaction was stopped after 150 minutes. The product was then extruded from the bottom of the polymerization reactor, cooled, and pelletized to obtain polyester chips.

[0073] The polyester chips obtained in Example 7 and Comparative Example 4 were tested according to Method A, Method B, and Method C, 5.1.1, of the national standard GB_T 14190-2017 Test Methods for Fiber Grade Polyester (PET) Chips. The test results are shown in Table 1 below.

[0074] Table 1

[0075] catalyst Intrinsic viscosity η (dL / g) L b Melting point (°C) Example 7 Example 1 0.732 88.0 5.5 246.9 Comparative Example 4 Comparative Example 3 0.734 88.3 5.1 242.3

[0076] As can be seen from the test results in Table 1, the catalytic activity of the titanium-containing composition prepared by the present invention as a catalyst is comparable to that of the titanium-containing composition prepared by using diethylene glycol as a solvent (under the same polymerization time, the intrinsic viscosity is comparable). Moreover, judging from the grayness of the L-value slice and the blue-yellowness of the b-value slice, it has almost no effect on the hue of the polyester prepared by the catalyst. However, in terms of the melting point of the polyester, since diethylene glycol was used as a solvent in Comparative Example 3, diethylene glycol entered the polyester backbone during the polymerization process, resulting in a significant decrease in the melting point of the polyester. In contrast, the titanium-containing composition prepared by the present invention has no effect on the polymerization process of the polyester, and therefore the polyester prepared by the present invention has a higher melting point.

[0077] 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-containing composition comprising a reaction product of the following components: a titanium compound, a solvent, a hydroxycarboxylic acid, and / or an amino acid.

2. The titanium-containing composition according to claim 1, characterized in that: The molar ratio of the titanium element in the titanium compound to the total molar ratio of the hydroxyl and carboxyl groups in the hydroxycarboxylic acid is 1:(0.4-10.0), preferably 1:(2.0-8.0), and / or, the molar ratio of the titanium element in the titanium compound to the total molar ratio of the amino and carboxyl groups in the amino acid is 1:(0.4-10.0), preferably 1:(2.0-8.0); and / or, Based on a total weight of 100 wt% of the titanium compound, solvent, hydroxycarboxylic acid, and / or amino acid, the titanium element in the titanium compound is 0.01-10 wt%, preferably 0.1-8 wt%.

3. The titanium-containing composition according to claim 1, characterized in that: The titanium compound is an organotitanium compound, preferably Ti(OR)4, wherein each R is independently selected from one of C1-C10 straight-chain alkyl, C1-C10 branched alkyl, and C1-C10 aryl, more preferably a C1-C6 straight-chain alkyl or a C1-C6 branched alkyl.

4. The titanium-containing composition according to claim 1, characterized in that: The hydroxycarboxylic acid is α-hydroxycarboxylic acid; preferably, the α-hydroxycarboxylic acid contains 1 to 3 hydroxyl groups; more preferably, the α-hydroxycarboxylic acid is at least one selected from citric acid, lactic acid, malic acid, tartaric acid, 2-hydroxyglutaric acid, 2-hydroxybutyric acid, glycolic acid, and mandelic acid; and / or, The amino acid is an α-amino acid, preferably at least one of glycine, alanine, valine, leucine, isoleucine, and serine.

5. The titanium-containing composition according to claim 1, characterized in that: The solvent is an ethylene glycol ester, preferably at least one of ethylene glycol monocarboxylate, ethylene glycol diester, and ethylene glycol carbonate, more preferably at least one of ethylene glycol monocarboxylate containing a C1-C10 straight-chain alkyl group and / or a C1-C10 branched alkyl group, ethylene glycol diester containing a C1-C10 straight-chain alkyl group and / or a C1-C10 branched alkyl group, and ethylene carbonate.

6. A method for preparing a titanium-containing composition according to any one of claims 1-5, the method comprising one of the following two methods: Method 1: Mix the titanium compound with a portion of the solvent to obtain mixture 1; mix the remaining solvent with the hydroxycarboxylic acid and / or amino acid to obtain mixture 2; then add mixture 2 to mixture 1 and perform a heated reaction to obtain the titanium-containing composition; Method 2: The solvent is mixed with hydroxycarboxylic acid and / or amino acid to prepare a mixture; the titanium compound is added to the mixture and heated to prepare the titanium-containing composition.

7. The method according to claim 6, characterized in that: In Method 1: The mass ratio of the titanium compound to a portion of the solvent is 1:(0.5-3), preferably 1:(0.5-2; and / or, The mass ratio of the remaining solvent to hydroxycarboxylic acid and / or amino acid is (1-9):1, preferably (1-5):

1.

8. The method according to claim 6, characterized in that: In Method 1: The mixing temperature of the titanium compound and a portion of the solvent is 0-50°C, preferably 20-50°C; and / or, The mixing temperature of the remaining solvent with the hydroxycarboxylic acid and / or amino acid is 0-50°C, preferably 20-50°C; and / or, The second mixture is added dropwise or in batches to the first mixture; and / or The reaction temperature of the heating reaction is 30-200℃, preferably 50-100℃, and / or the reaction time is 0.2-24h, preferably 1-10h.

9. The method according to claim 6, characterized in that: In Method Two: The mixing temperature of the solvent with the hydroxycarboxylic acid and / or amino acid is 0-50°C, preferably 20-50°C; and / or, The titanium compound is added dropwise or in batches to the mixture; and / or, The reaction temperature of the heating reaction is 30-200℃, preferably 50-100℃, and / or the reaction time is 0.2-24h, preferably 1-10h.

10. A polyester catalyst comprising at least one titanium-containing composition as described in any one of claims 1-5 or a titanium-containing composition prepared by the method as described in any one of claims 6-9.