Nanometer supported solid-phase titanium-based multi-metal catalyst, and preparation method therefor and use thereof

Abstract

Provided are a nanometer supported solid-phase titanium-based multi-metal catalyst, and a preparation method therefor and the use thereof. The catalyst comprises a carrier and an active component, wherein the active component comprises a primary active component and an auxiliary active component; and the carrier is a silica-coated modified inorganic porous material. The preparation method comprises the following steps: subjecting a carrier suspension, a water-soluble scandium salt, a water-soluble magnesium salt, a water-soluble cobalt salt, a water-soluble zinc salt and a water-soluble hydroxide to a precipitation reaction, filtering and heating treatment, so as to load an auxiliary active component onto a carrier; reacting a titanium source with an acid to obtain a reaction mixture; reacting the reaction mixture with the suspension of the carrier that has the auxiliary active component loaded thereon, so as to obtain a catalyst precursor; and reacting the catalyst precursor with a silicate ester and water, so as to load a primary active component onto the carrier, thereby obtaining the catalyst. When used for polyester synthesis, the catalyst can inhibit the hydrolysis of titanium, significantly improve the polymerization activity, inhibit side reactions and guarantee the hue of a product.

Description

A nano-supported solid-phase titanium-based multi-metal catalyst and its preparation method and use Technical Field

[0001] The invention relates to a nano-supported solid-phase titanium-based multi-metal catalyst and a preparation method and application thereof. Background Art

[0002] In polyester synthesis reactions, titanium catalysts are widely used due to their high efficiency in catalyzing esterification and polymerization reactions in unsaturated polyester synthesis, poly(1,3-trimethylene terephthalate) (PTT), poly(butylene terephthalate) (PBT), polyethylene naphthalate (PEN), poly(butylene succinate) (PBS), thermoplastic biodegradable plastic copolymers of butylene adipate and butylene terephthalate (PBAT), and linear polyester synthesis technology. The temperature range for the optimal high-efficiency and high-quality catalytic polymerization reaction of titanium catalysts themselves is 175-265°C. Within this range, the level of side reactions in the catalytic polymerization process is low, and the product quality is excellent. However, in the synthesis process of the most commonly used polyethylene terephthalate (PET) and its modified polyester, the polymerization reaction temperature is generally controlled at 275-295°C. Within this temperature range, although titanium-based catalysts can still achieve more efficient catalytic reaction efficiency, the level of side reactions catalyzed by titanium-based catalysts also increases significantly. Due to the large amount of cracking and unsaturated end groups produced in polyester, the color of PET products is seriously deteriorated, affecting the appearance of the product.

[0003] At present, the commonly used catalyst for PET polyester synthesis is antimony-based catalyst. The temperature range for the best catalytic effect of antimony-based catalyst is: 269-295℃. In this range, PET polyester polymerization reaction is dominant and the level of side reactions is very low. Therefore, antimony-based catalysts such as antimony trioxide, antimony acetate, and ethylene glycol antimony are widely used in the polyester industry.

[0004] However, antimony-based catalysts have the following obvious disadvantages: the metallic antimony element in antimony-based catalysts is a heavy metal. During the esterification, polymerization, spinning, manufacturing, printing and dyeing, and clothing use processes, trace amounts of antimony elements will continuously dissolve into the environment, causing environmental pollution. The large-scale use of antimony-based catalysts may cause serious environmental pollution.

[0005] The earliest titanate catalysts are very easy to hydrolyze to form solid-phase titanium dioxide, which makes their catalytic effect on esterification and polymerization reactions very unstable. The titanate catalyst hydrolyzed by the esterification reaction will be inactivated, resulting in a significant increase in the degree of subsequent side reactions. Although high-content phosphorus stabilizers can be used to seal the inactivated catalyst, the addition of a large amount of phosphorus stabilizers will also have a passivation effect on the activity of the titanium catalyst added to the polymerization, resulting in a decrease in catalytic activity.

[0006] The new liquid-phase titanium catalysts developed by DuPont, Shahariben, Zhuangyuan Xinfeng and others have solved the problem of catalyst hydrolysis to a certain extent. However, due to the high acidity of the catalysts, they produce a large viscosity drop in the spinning process, affecting product quality, and produce precipitation in the polymerization section, spinning box and phosphorus stabilizer, and block the pipes and boxes during long-term operation. Therefore, the effect of use is not ideal, and there are technical bottlenecks in large-scale promotion.

[0007] The citric acid-based titanium catalyst developed by the UK-based company Xinfeng completely solves the hydrolysis problem of titanium catalysts. However, for trifunctional citric acid, the catalyst acidity reaches a pH of approximately 1.0, and the third carboxyl group of citric acid participates in the polymerization reaction, thus affecting the quality of polyester products. Furthermore, the liquid catalyst is not resistant to light and cannot be stored for long periods in sunlight. The Ti-O-Ti bond within it changes color to purple under sunlight, affecting the product color and catalytic performance.

[0008] That is, the titanium-based catalysts currently used in polyester synthesis cannot effectively inhibit hydrolysis, improve polymerization activity, suppress the degree of side reactions, and ensure product quality such as color.

[0009] Summary of the Invention

[0010] The purpose of the present invention is to provide a method for preparing a nano-supported solid-phase titanium-based multi-metal catalyst. The catalyst obtained by this preparation method can inhibit the hydrolysis of titanium during polymerization, significantly improve the polymerization activity during polyester synthesis, significantly inhibit the occurrence of side reactions, and at the same time ensure that the polyester product has excellent quality such as color.

[0011] In order to achieve the above object, the technical solution adopted by the present invention is:

[0012] A method for preparing a nano-supported catalyst comprises a carrier and active components, wherein the active components comprise a main active component and a secondary active component, and the carrier is a silica-coated modified inorganic porous material. The preparation method comprises the following steps: subjecting a suspension of the carrier, a water-soluble scandium salt, a water-soluble magnesium salt, a water-soluble cobalt salt, a water-soluble zinc salt, and a water-soluble hydroxide to a precipitation reaction, filtering, and heating, so that the carrier is loaded with the secondary active component; reacting a titanium source with an acid to obtain a reaction mixture; reacting a suspension of the carrier loaded with the secondary active component with the reaction mixture to obtain a catalyst precursor; and reacting the catalyst precursor with a silicate and water, so that the carrier is loaded with the main active component, thereby obtaining the nano-supported catalyst.

[0013] In the present invention, nano-supported catalyst means that the size of the catalyst is at the nanometer level and it is a supported catalyst.

[0014] In the present invention, the primary active component and the secondary active component are defined based on the strength of their catalytic activity. The primary active component exerts the primary catalytic polymerization activity, while the secondary active component exerts a secondary catalytic polymerization activity. Generally, the primary active component can catalyze polymerization reactions alone, while the secondary active component cannot catalyze polymerization reactions alone. In the present invention, the titanium source refers to a compound containing titanium and serves as the raw material for the titanium-containing active component in the catalyst.

[0015] In some embodiments, the inorganic porous material has a particle size of 20 to 70 nm and a specific surface area of ​​220 to 400 m 2 / g.

[0016] In some embodiments, the inorganic porous material has a particle size of 25 to 40 nm and a specific surface area of ​​270 to 350 m 2 / g.

[0017] In some embodiments, the particle size of the nano-supported catalyst is 80 to 160 nm.

[0018] In the present invention, the particle size is the data tested by the GB / T 42208 2022 test standard; the specific surface area is the data tested by the GB / T 38691 2020 test standard.

[0019] In some embodiments, the inorganic porous material is selected from a combination of one or more of molecular sieves, pointillist, nanoporous alumina, nanoporous alumina-zirconia, porous silica, and nanoporous barium sulfate. The nanoporous barium sulfate can be prepared by reacting sulfuric acid with barium hydroxide or barium acetate in an ethylene glycol liquid phase.

[0020] The inventors of the present application discovered through research that, first, on a catalyst carrier, an aqueous solution of metal salts of four side-active components is subjected to a precipitation reaction with a water-soluble hydroxide, and the corresponding metal hydroxides are generated through co-precipitation, and the four metal hydroxides have a specific lattice structure. Then, through heat treatment, most of the hydroxides will generate corresponding oxides, and the oxides of the four metals also have a specific crystal structure. The oxides of the four metals and the remaining small portion of hydroxides that have not decomposed into oxides together form the side-active components of the catalyst.

[0021] A titanium source, such as tetraisopropyl titanate, tetrabutyl titanate or titanium tetrachloride, first reacts with an acid to generate titanium tetrahydroxide. The silicate reacts with water to generate silicon hydroxide containing hydroxyl groups. The titanium tetrahydroxide and the silicon hydroxide containing hydroxyl groups undergo a condensation reaction to generate a compound containing a Ti-O-Si bond. The compound contains titanium element, which serves as the main active component of the catalyst. At the same time, the compound does not contain hydroxyl groups, which can inhibit the hydrolysis of the catalyst when used to catalyze polyester polymerization, reduce the occurrence of side reactions during polymerization, and improve the hue of the polyester product.

[0022] Titanium tetrahydroxide and the undecomposed minor amounts of the four metal hydroxides in the secondary active components undergo a certain degree of condensation, forming a certain degree of bonding. In the catalyst of the present invention, the primary active component and the secondary active component act synergistically, jointly improving the catalyst's hydrolysis inhibition, increasing catalytic activity, and suppressing side reactions during polyester polymerization. Furthermore, the catalyst of the present invention exhibits good dispersion in ethylene glycol.

[0023] In some embodiments, the mass ratio of the active ingredient to the carrier is 11.3-25.0:75.0-88.7.

[0024] In some embodiments, the molar ratio of the main active component to the secondary active component is 3.3-10.0:8-15.

[0025] In some embodiments, the molar ratio of the water-soluble scandium salt, the water-soluble magnesium salt, the water-soluble cobalt salt, and the water-soluble zinc salt is 0.1-3.0:0.5-2.5:0.1-1.0:0.5-3.0.

[0026] In some embodiments, the water-soluble scandium salt, water-soluble magnesium salt, water-soluble cobalt salt, and water-soluble zinc salt are each selected from sulfates, acetates, or chlorides of the corresponding metal elements.

[0027] In some embodiments, the water-soluble hydroxide is selected from one or both of sodium hydroxide and potassium hydroxide.

[0028] In some embodiments, the titanium source is selected from a combination of one or more of tetraisopropyl titanate, tetrabutyl titanate, and titanium tetrachloride.

[0029] In some embodiments, the acid is selected from a combination of one or more of formic acid, acetic acid, propionic acid, oxalic acid, malonic acid, succinic acid, citric acid, and polyphosphoric acid.

[0030] In some embodiments, the silicate is selected from a combination of one or more of tetraethyl silicate, tetrabutyl silicate, and tetrapropyl silicate.

[0031] In some embodiments, the mass ratio of the titanium source to the acid is 1:0.5-2.0.

[0032] In some embodiments, the mass ratio of the silicate to the titanium source is 1:0.2-0.5.

[0033] In some embodiments, the water-soluble scandium salt, water-soluble magnesium salt, water-soluble cobalt salt, and water-soluble zinc salt are added dropwise to the suspension of the carrier in the form of an aqueous solution; the water-soluble hydroxide is added dropwise to the suspension of the carrier in the form of an aqueous solution; and the preparation method controls the simultaneous addition of the two.

[0034] In some embodiments, the molar concentration of the water-soluble scandium salt in the aqueous solution is 0.1 to 3.0 mol / L.

[0035] In some embodiments, the molar concentration of the water-soluble magnesium salt in the aqueous solution is 0.5 to 2.5 mol / L.

[0036] In some embodiments, the molar concentration of the water-soluble cobalt salt in the aqueous solution is 0.1 to 1.0 mol / L.

[0037] In some embodiments, the molar concentration of the water-soluble zinc salt in the aqueous solution is 0.5 to 3.0 mol / L.

[0038] In some embodiments, the molar concentration of the water-soluble hydroxide in its aqueous solution is 0.1 to 2.0 mol / L.

[0039] In some embodiments, the precipitation reaction is performed at a pH of 10-12.

[0040] In some embodiments, the precipitation reaction time is 8-11 hours.

[0041] In some embodiments, the precipitation reaction temperature is 70-130°C.

[0042] In some embodiments, the heat treatment temperature is 290-310°C.

[0043] In some embodiments, the heating treatment time is 2-6 hours.

[0044] In some embodiments, the preparation method includes the following steps: 1) heating the suspension of the carrier to 60-90°C, and simultaneously adding a mixed aqueous solution of a water-soluble scandium salt, a water-soluble magnesium salt, a water-soluble cobalt salt and a water-soluble zinc salt, and an aqueous solution of a water-soluble hydroxide to the suspension of the carrier under stirring for precipitation reaction. After the addition is completed, heating to 110-130°C to continue the reaction, adjusting the pH value to neutral, filtering, drying, heat-treating, and crushing to load the carrier with a side active component; 2) reacting a titanium source with an acid to obtain a reaction mixture; 3) dispersing the carrier loaded with the side active component in ethylene glycol, adding the reaction mixture to the ethylene glycol, reacting to obtain a catalyst precursor; 4) adding silicate and water to the catalyst precursor for reaction, removing the acid and water, and obtaining the nano-supported catalyst.

[0045] In some embodiments, the preparation method further includes the steps of dispersing the inorganic porous material in ethylene glycol or water, adding tetraethyl orthosilicate or sodium silicate and sodium hydroxide aqueous solution to the ethylene glycol or water for hydrolysis reaction, filtering, and drying to obtain the carrier.

[0046] The present invention also provides a nano-supported catalyst prepared by the aforementioned method for preparing the nano-supported catalyst. The catalyst can inhibit the hydrolysis of titanium during polymerization, significantly improve polymerization activity during polyester synthesis, significantly inhibit the occurrence of side reactions, and simultaneously ensure excellent quality, such as hue, of the polyester product.

[0047] The present invention also provides use of the aforementioned nano-supported catalyst for catalyzing polyester synthesis.

[0048] In some embodiments, the nano-supported catalyst is used alone or in combination with other catalysts during polyester synthesis. The nano-supported catalyst of the present invention can efficiently catalyze polyester synthesis alone, and can also be used in combination with other catalysts used in the prior art for catalyzing polyester synthesis, such as conventional titanium-based catalysts and antimony-based catalysts.

[0049] In some embodiments, the polyester is selected from one or more of polyethylene terephthalate, poly(1,3-propylene terephthalate), poly(butylene terephthalate), polyethylene naphthalate, and poly(butylene succinate). Polyethylene terephthalate has a high polymerization temperature, and the catalyst of the present invention can efficiently catalyze this polymerization reaction. For other polyesters, which are synthesized at lower temperatures, the catalyst of the present invention can also efficiently catalyze the polymerization.

[0050] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0051] The catalyst of the present invention uses a silica-coated modified inorganic porous material as a carrier, and the carrier can help improve the catalytic activity of the catalyst. At the same time, the present invention first performs a precipitation reaction on the catalyst carrier through an aqueous solution of metal salts of four side-active components and a water-soluble hydroxide, and generates corresponding metal hydroxides through co-precipitation, and the four metal hydroxides have a specific lattice structure. Then, most of the hydroxides are heated to generate corresponding oxides, and the oxides of the four metals also have a specific crystal structure. The oxides of the four metals and the remaining small portion of hydroxides that have not been decomposed into oxides together form the side-active components of the catalyst.

[0052] The main active component of the catalyst is a compound containing a Ti-O-Si bond, which does not contain a hydroxyl group. It can inhibit the hydrolysis of the catalyst when used to catalyze polyester polymerization, reduce the occurrence of side reactions during polymerization, and improve the hue of the polyester product.

[0053] In the catalyst of the present invention, the main active component and the secondary active component will undergo bonding to produce a synergistic effect, thereby jointly improving the catalyst's hydrolysis inhibition, increasing catalytic activity, and inhibiting side reactions during polyester polymerization.

[0054] The solid-phase titanium-based multi-metal catalyst of this invention is a porous, large-surface-area solid-phase catalyst with excellent dispersion in ethylene glycol. This catalyst overcomes the hydrolysis vulnerability of conventional liquid-phase titanium catalysts during esterification polymerization, exhibiting superior catalytic performance and effectively suppressing side reactions. Compared to traditional antimony-based catalysts, this catalyst achieves improved thermal and thermo-oxidative stability of high-viscosity melts, reducing the viscosity drop during melt delivery by approximately 12% to 18%.

[0055] When the catalyst of the present invention is used for polyester synthesis, the catalytic activity is improved, the polymerization time can be shortened, the occurrence of side reactions is inhibited, the chromaticity of the polyester product is improved, and the spinning effect of the fiber is improved. DETAILED DESCRIPTION

[0056] The above scheme is further described below with reference to specific examples. It should be understood that these examples are intended to illustrate the basic principles, main features, and advantages of the present invention, and the present invention is not limited in scope by the following examples. The implementation conditions used in the examples can be further adjusted according to specific requirements. The implementation conditions not specified are generally those used in routine experiments. Unless otherwise specified in the following examples, all raw materials were purchased commercially or prepared by conventional methods in the art.

[0057] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made in accordance with the spirit of the present invention are intended to be covered by the scope of protection of the present invention.

[0058] Example 1

[0059] This embodiment provides a nano-supported solid-phase titanium-based multi-metal catalyst, and uses it in the polymerization of PET. The specific steps are as follows:

[0060] Preparation of catalyst:

[0061] 1) Ethylene glycol is heated to 50° C., and accurately measured barium hydroxide octahydrate is slowly added to the reactor under high-speed stirring conditions (high-speed homogenizer: speed: 3000-6000 rpm) and stirred until completely dissolved. Then, 10% mass concentration of dilute sulfuric acid is quickly added to the reactor according to the molar ratio of barium ions, and high-speed stirring is maintained for 1.0 hour. The reaction heat causes the suspension to be heated to about 90° C., and the pH of the suspension is adjusted to be stable at 7.0. The suspension is then heated and refluxed to evaporate water, and the temperature is lowered to 170° C. Ethylene glycol is then added to make the mass content of barium sulfate powder 20%, and then stirred for 0.5 hour. The pH value is measured again until the pH value of the suspension is completely stable at 7.0. The obtained barium sulfate powder has a particle size of 20 nm and a specific surface area of ​​350 m 2 / g.

[0062] 2) Tetraethyl silicate and sodium hydroxide were added dropwise to a suspension of barium sulfate in ethylene glycol at a pH of 7.0, so that a silicon dioxide layer was coated on the surface of the barium sulfate powder. After aging for 6 hours, a mixed aqueous solution of hydrated scandium sulfate, magnesium sulfate, cobalt acetate, and zinc acetate (wherein the molar concentration of hydrated scandium sulfate was 2.5 mol / L, the molar concentration of magnesium sulfate was 0.5 mol / L, the molar concentration of cobalt acetate was 0.5 mol / L, and the molar concentration of zinc acetate was 0.5 mol / L) and a 0.5 mol / L aqueous sodium hydroxide solution were added dropwise to the reactor simultaneously under high-speed stirring, in amounts such that the total valence of the four metal ions was equal to the total valence of the hydroxide ions. During the addition, the pH of the suspension was strictly controlled to be between 10.0 and 10.2.

[0063] After the addition is completed, the reaction system is heated to 120°C and aged for 5.0 hours. Then, the pH value of the suspension is adjusted to 7.0 with 10% mass concentration of dilute sulfuric acid. After stirring for 1.0 hour, it is filtered and washed three times with distilled water until neutral. After the filtered powder is dried, it is calcined at 290°C in a muffle furnace for 4.0 hours, cooled and crushed, and finally finely crushed with a jet mill until the particle size is 0.15 μm.

[0064] The temperature is lowered to 170°C at the bottom of the reactor. Tetraisopropyl titanate and glacial acetic acid are then mixed in a weight ratio of 1:0.5 to obtain a mixed solution. A certain amount of the mixed solution is then slowly added dropwise to the reactor. After the addition is complete, the mixture is aged for another hour. Water is then added dropwise to the reactor, along with tetraethyl silicate, to cause a hydrolysis reaction, thereby coating the catalyst with a silicified layer. The reaction is then stirred and refluxed at 80°C for 6 hours. Finally, the temperature is raised to 135°C. Once a large amount of acetic acid-water begins to elute, ethylene glycol is added to the reactor. The temperature is then raised until the acetic acid is essentially completely elutes. Vacuum purge is then performed. When the elute components, such as acetic acid, reach a predetermined amount, the purge is stopped and the reaction system is cooled to room temperature. The suspension is then ultrafinely ground to obtain an ethylene glycol suspension of the catalyst with a solids content of 10% and a catalyst particle size of 85 nm. In the catalyst, by mass percentage, the carrier is 83.4%, the main active component is 6.6%, of which the titanium content is 2.0%, and the secondary active component is 10%. Among the secondary active components, the molar ratio of scandium, magnesium, cobalt and zinc elements is 5:1:1:1.

[0065] PET polymerization:

[0066] Purified terephthalic acid, ethylene glycol, and an ethylene glycol suspension of the above-mentioned catalyst were added to a 70L polymerization kettle for polymerization, first conducting an esterification reaction and then a polymerization reaction. The molar ratio of purified terephthalic acid to ethylene glycol was 1:1.52, and the catalyst was used in an amount calculated as titanium element, which accounted for 10 ppm of the mass of the PET polymer. The final esterification temperature (the temperature at which esterification terminated) was 255.6°C, and the esterification time was 3.60 hours. The esterification water output was 4030 mL. The polymerization time was 2.73 hours, the polymerization vacuum was 55.4 Pa, the final polymerization temperature (the temperature at which polymerization terminated, i.e., the temperature at the start of polymerization, which is the final esterification temperature) was 278.5°C, and the current value of the polymerization discharge was 2.55 A when the stirring shaft of the polymerization kettle was stirred at a stirring speed of 600 rpm.

[0067] Example 2

[0068] Example 2 provides a nano-supported solid-phase titanium-based multi-metal catalyst, which is used in the polymerization of PET. The specific steps are basically the same as those in Example 1, except that step 1) is not performed when preparing the catalyst, and the ethylene glycol suspension of barium sulfate with a pH value of 7.0 in step 2) is replaced by a water suspension of γ-nanoporous alumina with a pH value of 7.0, wherein the particle size of the γ-nanoporous alumina is 35 nm and the specific surface area is 240 m 2 / g; and the polymerization reaction conditions were adjusted, as shown in Table 1 below. The slurry molar ratio refers to the molar ratio of purified terephthalic acid and ethylene glycol.

[0069] Example 3

[0070] Example 3 provides a nano-supported solid-phase titanium-based multi-metal catalyst, which is used in the polymerization of PET. The specific steps are basically the same as those in Example 1, except that step 1) is not performed when preparing the catalyst, and the ethylene glycol suspension of barium sulfate with a pH value of 7.0 in step 2) is replaced with a water suspension of nanoporous alumina-zirconia powder with a pH value of 7.0, wherein the particle size of the nanoporous alumina-zirconia powder is 60 nm and the specific surface area is 300 m 2 / g; and the polymerization reaction conditions were adjusted, as shown in Table 1 below.

[0071] Example 4

[0072] Example 4 provides a nano-supported solid-phase titanium-based multi-metal catalyst, which is used in the polymerization of PET. The specific steps are basically the same as those in Example 1, except that step 1) is not performed when preparing the catalyst, and the ethylene glycol suspension of barium sulfate with a pH value of 7.0 in step 2) is replaced by a water suspension of spar with a pH value of 7.0, wherein the particle size of the spar is 40 nm and the specific surface area is 250 m 2 / g; and the polymerization reaction conditions were adjusted, as shown in Table 1 below.

[0073] Example 5

[0074] Example 5 provides a nano-supported solid-phase titanium-based multi-metal catalyst, which is used in the polymerization of PET. The specific steps are basically the same as those in Example 1, except that step 1) is not performed when preparing the catalyst, and the ethylene glycol suspension of barium sulfate with a pH value of 7.0 in step 2) is replaced by an aqueous suspension of nanoporous silica with a pH value of 7.0, wherein the particle size of the nanoporous silica is 45 nm and the specific surface area is 270 m 2 / g; and the polymerization reaction conditions were adjusted, as shown in Table 1 below.

[0075] Example 6

[0076] Example 6 provides a nano-supported solid-phase titanium-based multi-metal catalyst, which is used in the polymerization of PET. The specific steps are basically the same as those in Example 1, except that step 1) is not performed when preparing the catalyst, and the ethylene glycol suspension of barium sulfate with a pH value of 7.0 in step 2) is replaced by a water suspension of an ultrafine porous molecular sieve with a pH value of 7.0, wherein the particle size of the ultrafine porous molecular sieve is 50 nm and the specific surface area is 280 m 2 / g; and the polymerization reaction conditions were adjusted, as shown in Table 1 below.

[0077] Example 7

[0078] Example 7 provides a nano-supported solid-phase titanium-based multi-metal catalyst, which is used in the polymerization of PET. The specific steps are essentially the same as those in Example 1, with the only difference being that the amounts of the four metal aqueous solutions and tetraisopropyl titanate used in the catalyst preparation are varied. The resulting catalyst comprises, by mass, 86.0% support, 10.0% primary active component, 3.0% titanium, and 4% secondary active component. The molar ratio of scandium, magnesium, cobalt, and zinc in the secondary active component is 5:1:1:1. The polymerization reaction conditions are modified, as shown in Table 1 below.

[0079] Example 8

[0080] Example 8 provides a nano-supported solid-phase titanium-based multi-metal catalyst, which is used in the polymerization of PET. The specific steps are essentially the same as those in Example 1, with the only difference being that the amounts of the four metal aqueous solutions and tetraisopropyl titanate used in the catalyst preparation are varied. The resulting catalyst comprises, by weight, 75.0% support, 10.0% primary active component, 3.0% titanium, and 15% secondary active component. The molar ratio of scandium, magnesium, cobalt, and zinc in the secondary active component is 5:1:1:1. The polymerization reaction conditions are modified, as shown in Table 1 below.

[0081] Comparative Example 1

[0082] Comparative Example 1 provides a polymerization method for PET, and its specific steps are as follows:

[0083] Purified terephthalic acid, ethylene glycol, and the catalyst antimony glycolate were added to a 70L polymerization vessel for polymerization, first undergoing esterification and then polymerization. The catalyst was used in an amount of 210 ppm (as antimony element) based on the mass of the PET polymer. Specific polymerization conditions are shown in Table 1. As can be seen, using the traditional antimony glycolate catalyst prolonged both the esterification and polymerization times, and increased both the final esterification and polymerization temperatures.

[0084] Comparative Example 2

[0085] Comparative Example 2 provides a polymerization method for PET, and its specific steps are as follows:

[0086] Purified terephthalic acid, ethylene glycol, and tetrabutyl titanate catalyst were added to a 70L polymerization vessel for polymerization, first undergoing esterification and then polymerization. The catalyst was used in an amount of 10 ppm (calculated as titanium element) based on the mass of the PET polymer. Specific polymerization conditions are shown in Table 1. As can be seen, using tetrabutyl titanate as a catalyst prolonged both the esterification and polymerization times, and increased both the final esterification and polymerization temperatures.

[0087] Comparative Example 3

[0088] Comparative Example 3 provides a polymerization method for PET, the specific steps of which are as follows:

[0089] Purified terephthalic acid, ethylene glycol, and a titanium citrate catalyst imported from the UK were added to a 70L polymerization kettle for polymerization, first undergoing an esterification reaction, followed by a polymerization reaction. The catalyst was used in an amount of 10 ppm (based on the mass of the PET polymer) calculated as titanium. Specific polymerization conditions are shown in Table 1 below. As can be seen, using titanium citrate as a catalyst shortens the esterification time and polymerization time, and reduces the final esterification and polymerization temperatures, compared to conventional ethylene glycol antimony catalysts. The catalyst of the present invention achieves comparable esterification and polymerization results to titanium citrate.

[0090] Comparative Example 4

[0091] Comparative Example 4 provides a nano-supported solid-phase titanium-based multi-metal catalyst, which is used in the polymerization of PET. The specific steps are basically the same as those in Example 1, except that hydrated scandium sulfate is not added in step 2) when preparing the catalyst. In the final catalyst, the carrier is 83.4% by mass, the main active component is 6.6%, the titanium content is 2.0%, and the secondary active component is 10%. The molar ratio of magnesium, cobalt, and zinc in the secondary active component is 1:1:1. During the polymerization reaction, the catalyst is used in an amount of 10 ppm based on the mass of the PET polymer, calculated as titanium. The specific polymerization reaction conditions are shown in Table 1 below.

[0092] Comparative Example 5

[0093] Comparative Example 5 provides a nano-supported solid-phase titanium-based multi-metal catalyst, which is used in the polymerization of PET. The specific steps are basically the same as those in Example 1, except that magnesium sulfate is not added in step 2) when preparing the catalyst. The final catalyst has a support content of 83.4% by mass, a main active component of 6.6%, a titanium content of 2.0%, and a secondary active component of 10%. The molar ratio of scandium, cobalt, and zinc in the secondary active component is 5:1:1. During the polymerization reaction, the catalyst is used in an amount calculated as titanium, which accounts for 10 ppm of the mass of the PET polymer. The specific polymerization reaction conditions are shown in Table 1 below.

[0094] Comparative Example 6

[0095] Comparative Example 6 provides a nano-supported solid-phase titanium-based multi-metal catalyst, which is used in the polymerization of PET. The specific steps are basically the same as those in Example 1, except that cobalt sulfate is not added in step 2) when preparing the catalyst. In the final catalyst, the carrier is 83.4% by mass, the main active component is 6.6%, the titanium content is 2.0%, and the secondary active component is 10%. In the secondary active component, the molar ratio of scandium, magnesium, and zinc is 5:1:1. During the polymerization reaction, the catalyst is used in an amount of 10 ppm based on the mass of the PET polymer, calculated as titanium. The specific polymerization reaction conditions are shown in Table 1 below.

[0096] Comparative Example 7

[0097] Comparative Example 7 provides a nano-supported solid-phase titanium-based multi-metal catalyst, which is used in the polymerization of PET. The specific steps are basically the same as those in Example 1, except that zinc sulfate is not added in step 2) when preparing the catalyst. The final catalyst has a support content of 83.4% by mass, a main active component of 6.6%, a titanium content of 2.0%, and a secondary active component of 10%. The molar ratio of scandium, magnesium, and cobalt in the secondary active component is 5:1:1. During the polymerization reaction, the catalyst is used in an amount calculated as titanium, which accounts for 10 ppm of the mass of the PET polymer. The specific polymerization reaction conditions are shown in Table 1 below.

[0098] Table 1

[0099] The polyester melts obtained in Examples 1-7 and Comparative Examples 1-7 were sliced, and various properties of the slices were tested using the GB / T 14190-2017 standard. The results are shown in Table 2 below, where IV refers to intrinsic viscosity, which is measured in a mixed solvent of phenol and tetrachloroethane in a volume ratio of 3:2. DEG, H2O, ash, Fe, and agglomerated particles refer to the mass fractions of diethylene glycol, water, ash, Fe element, and agglomerated particles in the polyester, respectively. MP refers to melting point.

[0100] Table 2

[0101] The polyester melts obtained in Examples 1-7 and Comparative Examples 1-7 were spun in a spinning beam. The spinning process parameters and spinning conditions are shown in Table 3 below, and polyester fibers of the variety FDY and the specification of 66 dtex / 36f were obtained.

[0102] Table 3

[0103] During the spinning process, the spinning viscosity drop performance is shown in Table 4 below, where melt viscosity refers to the viscosity during spinning, melt viscosity drop refers to the difference between wet chip viscosity and melt viscosity, and the following viscosities are all intrinsic viscosities, all in dL / g, measured in a mixed solvent of phenol and tetrachloroethane with a volume ratio of 3:2.

[0104] Table 4

[0105] The physical and chemical properties of the spun fiber products were tested according to the GBT 8960-2015 test standard. The results are shown in Table 5 below, where 10% strength refers to the force required to stretch the fiber by 10%.

[0106] Table 5

[0107] It can be seen that the use of the specific nano-supported solid-phase titanium-based multi-metal catalyst of the present invention, compared with the traditional titanium or antimony catalysts, or catalysts whose side-active components do not contain the four metal oxides of the present invention, can better inhibit the hydrolysis of the titanium catalyst during the polymerization process, inhibit the occurrence of side reactions, and improve the hue and spinning performance of the polyester product.

[0108] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the present invention and implement it accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent variations or modifications based on the spirit and essence of the present invention are intended to be encompassed by the scope of protection of the present invention.

Claims

1. A preparation method of a nano-loaded catalyst, the catalyst comprising a carrier and an active component, the active component comprising a main active component and a secondary active component, characterized in that: The carrier is an inorganic porous material modified by silica coating. The preparation method includes the following steps: performing a precipitation reaction on a suspension of the carrier, a water-soluble scandium salt, a water-soluble magnesium salt, a water-soluble cobalt salt, a water-soluble zinc salt, and a water-soluble hydroxide, filtering, and heat-treating to load the carrier with co-catalytic components; reacting a titanium source with an acid to obtain a reaction mixture; reacting a suspension of the carrier loaded with co-catalytic components with the reaction mixture to obtain a catalyst precursor; and reacting the catalyst precursor with a silicate ester and water to load the carrier with the main catalytic component, thereby obtaining the nano-loaded catalyst.

2. The preparation method of the nano-loaded catalyst according to claim 1, characterized in that: The particle size of the inorganic porous material is 20 to 70 nm, and the specific surface area is 220 to 400 m 2 / g; and / or, the particle size of the nano-loaded catalyst is 80 to 160 nm.

3. The preparation method of the nano-loaded catalyst according to claim 1, characterized in that: The particle size of the inorganic porous material is 25 to 40 nm, and the specific surface area is 270 to 350 m 2 / g.

4. The preparation method of the nano-loaded catalyst according to claim 1, characterized in that: The inorganic porous material is selected from one or a combination of more of molecular sieves, feldspars, nano-porous alumina, nano-porous alumina-zirconia, porous silica, and nano-porous barium sulfate.

5. The preparation method of the nano-loaded catalyst according to claim 1, wherein: The mass ratio of the catalytic components to the carrier is 11.3-25.0:75.0-88.

7.

6. The preparation method of the nano-loaded catalyst according to claim 1, wherein: The molar ratio of the main catalytic component to the co-catalytic components is 3.3-10.0:8-15.

7. The preparation method of the nano-loaded catalyst according to claim 1, wherein: The molar ratio of the water-soluble scandium salt, the water-soluble magnesium salt, the water-soluble cobalt salt, and the water-soluble zinc salt is 0.1-3.0:0.5-2.5:0.1-1.0:0.5-3.

0.

8. The preparation method of the nano-loaded catalyst according to claim 1, characterized in that: The water-soluble scandium salt, the water-soluble magnesium salt, the water-soluble cobalt salt, and the water-soluble zinc salt are respectively selected from sulfates, acetates, or chlorides of the corresponding metal elements; and / or, the water-soluble hydroxide is selected from one or both of sodium hydroxide and potassium hydroxide; and / or, the titanium source is selected from one or a combination of more of tetraisopropyl titanate, tetrabutyl titanate, and titanium tetrachloride.

9. The preparation method of the nano-loaded catalyst according to claim 1, characterized in that: The acid is selected from one or a combination of more of formic acid, acetic acid, propionic acid, oxalic acid, malonic acid, succinic acid, citric acid, and polyphosphoric acid; and / or, the silicate ester is selected from one or a combination of more of tetraethyl silicate, tetrabutyl silicate, and tetrapropyl silicate.

10. The preparation method of the nano-loaded catalyst according to claim 1, wherein: The mass ratio of the titanium source to the acid is 1:0.5-2.0; and / or, the mass ratio of the silicate ester to the titanium source is 1:0.2-0.

5.

11. The preparation method of the nano-loaded catalyst according to claim 1, characterized in that: The water-soluble scandium salt, the water-soluble magnesium salt, the water-soluble cobalt salt, and the water-soluble zinc salt are added dropwise to the suspension of the carrier in the form of an aqueous solution; the water-soluble hydroxide is added dropwise to the suspension of the carrier in the form of an aqueous solution; and the preparation method controls the synchronous addition of the two.

12. The preparation method of the nano-loaded catalyst according to claim 11, characterized in that: The molar concentration of the water-soluble scandium salt in the aqueous solution is 0.1-3.0 mol / L; and / or, the molar concentration of the water-soluble magnesium salt in the aqueous solution is 0.5-2.5 mol / L; and / or, the molar concentration of the water-soluble cobalt salt in the aqueous solution is 0.1-1.0 mol / L; and / or, the molar concentration of the water-soluble zinc salt in the aqueous solution is 0.5-3.0 mol / L; and / or, the molar concentration of the water-soluble hydroxide in its aqueous solution is 0.1-2.0 mol / L.

13. The preparation method of the nano-loaded catalyst according to claim 1, characterized in that: The precipitation reaction is carried out under the condition of a pH of 10-12; and / or, the time of the precipitation reaction is 8-11 hours; and / or, the temperature of the precipitation reaction is 70-130 °C.

14. The preparation method of the nano-loaded catalyst according to claim 1, characterized in that: The temperature of the heat treatment is 290 - 310 °C; and / or, the time of the heat treatment is 2 - 6 hours.

15. The preparation method of the nano-loaded catalyst according to claim 1, wherein: The preparation method includes the following steps: 1) heating the suspension of the carrier to 60 - 90 °C, and simultaneously dropping a mixed aqueous solution of a water-soluble scandium salt, a water-soluble magnesium salt, a water-soluble cobalt salt, and a water-soluble zinc salt, and an aqueous solution of a water-soluble hydroxide into the suspension of the carrier under stirring for precipitation reaction. After the dropping is completed, heating to 110 - 130 °C for continuous reaction, adjusting the pH value to neutral, filtering, drying, heat-treating, and pulverizing to load the secondary active component on the carrier; 2) reacting a titanium source with an acid to obtain a reaction mixture; 3) dispersing the carrier loaded with the secondary active component into ethylene glycol, and dropping the reaction mixture into the ethylene glycol for reaction to obtain a catalyst precursor; 4) dropping a tetraethyl orthosilicate and water into the catalyst precursor for reaction to remove the acid and water to obtain the nano-loaded catalyst.

16. The preparation method of the nano-loaded catalyst according to claim 15, wherein: The preparation method further includes the step of dispersing the inorganic porous material into ethylene glycol or water, dropping tetraethyl orthosilicate or sodium silicate, and an aqueous sodium hydroxide solution into the ethylene glycol or water for hydrolysis reaction, filtering, and drying to obtain the carrier.

17. A nano-loaded catalyst prepared by the preparation method of the nano-loaded catalyst according to any one of claims 1 - 16.

18. Use of the nano-loaded catalyst according to claim 17 for catalytic polyester synthesis.

19. The use according to claim 18, wherein: During polyester synthesis, the nano-loaded catalyst is used alone, or the nano-loaded catalyst is used in combination with other catalysts.

20. The use according to claim 18, characterized in that: The polyester is selected from one or more combinations of polyethylene terephthalate, poly(trimethylene terephthalate), polybutylene terephthalate, polyethylene naphthalate, and polybutylene succinate.

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