A supported allyl acetate catalyst, its preparation method and application

Abstract

This invention discloses a supported allyl acetate catalyst, its preparation method, and its applications. The catalyst contains a support, and an active component, ligands, and co-active components supported on the support. The support is silicon carbide. The active component is selected from metals Pd, Au, and Cu. The co-active component is selected from alkali metal acetates. The ligands are selected from isopropylacrylamide, sodium (4,4'-di-tert-butyl-2,2'-bipyridine)bis[(2-pyridyl)phenyl], sodium terpyridine chloride, paclitaxel, and thermosensitive hydrogel. This invention yields a supported allyl acetate catalyst with an overall "honeycomb" structure and an internal component distribution that is "more abundant on the outside and less abundant on the inside." The catalyst prepared by this invention has the characteristics of uniform and firmly anchored composition, good thermal conductivity, good stability, long catalyst lifetime, high catalyst space-time yield, and high product selectivity.

Description

TECHNICAL FIELD

[0001] The present application relates to a supported allyl acetate catalyst and a preparation method thereof, in particular to a catalyst for synthesizing allyl acetate from acetic acid, oxygen and propylene. BACKGROUND

[0002] Allyl acetate is a slightly soluble in water, easily soluble in alcohol and ether, can be dissolved in acetone colorless flammable liquid, mainly used for the production of propylene alcohol and epichlorohydrin.

[0003] EP0361484A2 discloses a preparation method of a supported catalyst of main active component palladium and auxiliary active component copper, which is prepared by impregnating a mixed solution of noble metal palladium and auxiliary agent copper on the carrier, then precipitating by alkaline precipitant, reducing in reducing atmosphere, washing, drying, impregnating potassium acetate and drying to obtain the catalyst. The catalyst obtained by the method has low space-time yield and selectivity.

[0004] TW161027B discloses a preparation method of a catalyst supported by main active component noble metal and auxiliary active component metal. The method uses alumina, silicon dioxide, activated carbon, silicon dioxide-aluminum oxide, pumice and titanium oxide as the carrier, uses palladium as the active component, and uses lead, copper, ruthenium and rhenium as the auxiliary agent, and the catalyst is obtained by impregnation and reduction. The active component and the auxiliary agent of the catalyst prepared by the method are easy to lose, the activity and selectivity are poor, and it is difficult to meet the requirements of industrial production.

[0005] CN106582871B discloses a method for preparing allyl acetate, and the specific preparation process is as follows: (1) a coating liquid obtained by mixing modified metal element hydroxide or oxide and silica sol is coated on the surface of porous silica to obtain a carrier by drying and burning; (2) the carrier is impregnated with an impregnation liquid containing Pd compound and Cu compound to obtain catalyst precursor I; (3) the Pd compound and Cu compound are converted into a precipitated form by using an alkaline solution to obtain catalyst precursor II; (4) the compound state Pd and Cu in the precipitated form are reduced to metal Pd and Cu to obtain catalyst precursor III; (5) a co-catalyst solution is impregnated and dried to obtain the catalyst. The catalyst obtained by the method can solve the problems of low activity and selectivity of the catalyst to some extent, but the distribution state of the active component is poor, it is difficult to maintain long-term activity and selectivity, the active component is easy to lose, and it is not suitable for industrial production.

[0006] The above application has the problems of low activity, poor selectivity, easy loss of active component, insufficient stability, short service life and other problems, and is not suitable for industrial production.

[0007] Therefore, it is expected to improve the catalyst and the preparation method thereof on the basis of the existing technology, and to provide a more industrial application value catalyst and preparation method of allyl acetate. SUMMARY

[0008] In view of the above problems in the prior art, the present application provides a supported allyl acetate catalyst and a preparation method thereof. The catalyst contains a carrier, and an active component, a ligand and an active component-supporting component supported on the carrier, and the catalyst as a whole has a "honeycomb" structure, and the active component is distributed in a "more outside and less inside" state.

[0009] In the present application, the metal salt containing the active component is prepared into a solution, and then the solution is coordinated with the ligand and loaded on the carrier. After precipitation and reduction, the auxiliary metal salt is prepared into a solution and impregnated by precipitation to obtain a supported allyl acetate catalyst which has a "honeycomb" structure as a whole, and the internal components are distributed in a "more outside and less inside" state. The catalyst prepared by the present application has the characteristics of uniform and firm composition, good heat conduction performance, good stability, long catalyst life, high space-time yield of the catalyst, and high product selectivity.

[0010] To achieve the above object, the technical scheme adopted by the present application is as follows:

[0011] The present application provides a supported allyl acetate catalyst, which contains a carrier, and an active component, a ligand and an active component-supporting component supported on the carrier.

[0012] The carrier is a silicon carbide material.

[0013] The active component is selected from at least one of metals Pd, Au and Cu.

[0014] The active component-supporting component is selected from at least one of alkali metal acetate, preferably sodium acetate and / or potassium acetate.

[0015] The ligand is selected from at least one of isopropyl acrylamide, (4,4'-di-tert-butyl-2,2'-bipyridine) bis[(2-pyridyl) phenyl] sodium, trispyridine sodium chloride, paclitaxel and thermosensitive hydrogel.

[0016] In the present application, the carrier is a silicon carbide material, which is selected from at least one of silicon carbide balls, silicon carbide rods and silicon carbide rings, and more preferably is silicon carbide balls.

[0017] The silicon carbide material has a particle size of 1-5 mm, preferably 2-3 mm.

[0018] In the present application, the active component has a loading amount of 0.1-10.0 wt%, preferably 1-10.0 wt% based on the mass of the carrier.

[0019] In the present application, the active component loading is 1.0-10.0wt%, preferably 1.0-5.0wt%, based on the carrier mass.

[0020] In the present application, the ligand loading is 0.05-20.0wt%, preferably 0.1-10.0wt%, based on the carrier mass.

[0021] In the present application, the allyl acetate catalyst has a particle size of 1-5mm, preferably 2-3mm; a specific surface area of 50-800m 2 / g, preferably 200-600m 2 / g; a pore volume of 0.2-1.0cm 3 / g, preferably 0.2-0.6cm 3 / g; a pore size of 5-20nm, preferably 10-15nm.

[0022] In the present application, the allyl acetate catalyst has a "honeycomb" structure, and the internal components are distributed in a "more outside and less inside" manner. Preferably, the active component concentration decreases by 10-20wt% for every 10μm inward extension from the shell layer.

[0023] In the detailed embodiment of the present application, as a preferred example, the present application provides a preparation method of the above-mentioned supported allyl acetate catalyst, comprising the following steps:

[0024] (1) preparing a solution containing a metal salt of active component, then adding a carrier and a ligand for coordination reaction, and adding a precipitant for precipitation reaction to obtain a reaction solution containing precursor A;

[0025] (2) adding a reducing agent to the reaction solution of step (1) for reduction reaction, and then washing and drying to obtain precursor B;

[0026] (3) immersing the precursor B of step (2) in a solution containing a promoter component, and drying after taking out to obtain a supported allyl acetate catalyst.

[0027] In step (1) of the present application, the solution containing a metal salt of active component is an aqueous solution, and the concentration is 5-30wt%, preferably 10-20wt%.

[0028] The metal salt containing active component is selected from at least one of chloride, nitrate and acetate of Pd, Au and Cu, preferably at least one of chloride of Pd, Au and Cu.

[0029] In step (1) of the present application, the carrier is selected from at least one of silicon carbide material, preferably at least one of silicon carbide ball, silicon carbide rod and silicon carbide ring, and more preferably silicon carbide ball.

[0030] The silicon carbide material has a particle size of 1-5 mm, preferably 2-3 mm.

[0031] In step (1) of the present application, the mass ratio of the active component-containing metal salt solution to the carrier mixed with the metal salt therein is 1:1-100, preferably 1:2-50.

[0032] In step (1) of the present application, the ligand is at least one selected from isopropyl acrylamide, (4,4'-di-tert-butyl-2,2'-bipyridine) bis[(2-pyridyl)phenyl]sodium, trispyridine sodium chloride, paclitaxel, and a thermosensitive hydrogel, and is preferably isopropyl acrylamide.

[0033] The mass ratio of the ligand to the carrier is 1:5-200, preferably 1:10-100.

[0034] In step (1) of the present application, the precipitant is at least one selected from potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, potassium silicate, and sodium silicate, and is preferably at least one selected from sodium hydroxide, sodium silicate, and sodium carbonate.

[0035] The amount of the precipitant is 1-20 times, preferably 1-5 times, the molar amount of the metal in the active component-containing metal salt solution.

[0036] Preferably, the precipitant is prepared as an aqueous solution for use, and the concentration is 1-20 wt%, preferably 5-10 wt%.

[0037] In step (1) of the present application, the coordination reaction is carried out at a temperature of 10-50°C, preferably 20-30°C, for 10-72 h, preferably 20-40 h.

[0038] In step (1) of the present application, the precipitation reaction is carried out at a temperature of 10-50°C, preferably 20-30°C, for 10-72 h, preferably 20-40 h.

[0039] In step (2) of the present application, the reducing agent is at least one selected from ethylene, propylene, hydrogen, hydrazine hydrate, and formaldehyde, and is preferably at least one selected from hydrogen, propylene, and hydrazine hydrate.

[0040] The amount of the reducing agent added is 0.5-20 times, preferably 1-15 times, the molar amount of the metal in the active component-containing metal salt solution in step (1).

[0041] In step (2) of the present application, the reduction reaction is carried out at a temperature of 10-50°C, preferably 20-30°C, for 5-40 h, preferably 10-20 h.

[0042] In step (2) of the present application, the drying temperature is 100-150°C, and the drying time is 2-10 h.

[0043] In step (3) of the present application, the solution containing the promoter component is an aqueous solution with a concentration of 1-20 wt%, preferably 5-10 wt%;

[0044] The promoter component is selected from at least one of alkali metal acetate, preferably potassium acetate;

[0045] The mass ratio of the precursor B to the solution containing the promoter component is 1:0.1-20, preferably 1:0.2-10.

[0046] In step (3) of the present application, the impregnation is carried out at a temperature of 10-50℃ for 5-36h.

[0047] In step (3) of the present application, the drying is carried out at a temperature of 100-150℃ for 2-10h.

[0048] The allyl acetate catalyst provided by the present application has a specially designed "honeycomb-like" structure, which can make the active component of the catalyst uniformly distributed in a specific position, has good dispersity and thermal conductivity, and makes the catalyst have excellent activity and selectivity. The present application forms a catalyst structure with specific "honeycomb-like" and good thermal conductivity through the coordination reaction of the carrier and the ligand while loading the active component, which can greatly improve the thermal conductivity of the catalyst. The "honeycomb-like" structure can also make the active component of the catalyst distributed in a specific position, has high dispersity, so that the heat released during the reaction of the catalyst will not be too concentrated, avoiding the low selectivity of the product caused by the difficulty in removing the reaction heat, and the poor stability and service life of the catalyst. At the same time, the active component of the catalyst has a distribution state of "more outside and less inside", which can make the raw materials be converted in time when contacting the catalyst and be quickly desorbed, avoiding the diffusion difficulty caused by the internal reaction of a large amount of raw materials and the low activity and selectivity caused by excessive reaction, and the formation of excessive cracking products to block the pores and cover the active sites. The selected carrier and the ligand can also anchor the active component and form a more stable structure during preparation, so as to ensure that the catalyst can play a catalytic role without falling off and causing loss, and improve the economy. The heat-sensitive ligand can convert the ionic active component generated during the reaction into elemental active component in time, so as to play a catalytic role again.

[0049] The present application also provides the application of the above-mentioned allyl acetate catalyst, which is suitable for synthesizing allyl acetate from acetic acid, oxygen and propylene.

[0050] As a preferred embodiment, the present application provides a preparation method of allyl acetate, which comprises the following steps: using a fixed bed reactor, and reacting propylene, oxygen, acetic acid and water in the presence of the above-mentioned catalyst to prepare allyl acetate.

[0051] In the present application, the molar ratio of propylene to oxygen, acetic acid and water is 1:0.3-1:0.2-1:0.3-1, for example 1:0.4:0.5:0.5.

[0052] In the present application, the reaction temperature is 120-180℃, preferably 140-170℃; the pressure is 0.6-0.9MPaG, preferably 0.65-0.85MPaG; the reaction volume space velocity is 1500-2500h -1 , preferably 1800-2000h -1 .

[0053] Compared with the prior art, the technical scheme of the present application has the beneficial effects that:

[0054] The allyl acetate catalyst of the present application has a specially designed "honeycomb-like" structure, which can greatly improve the thermal conductivity of the catalyst, and the dispersion degree of the active component is high, so that the reaction heat of the catalyst is not too concentrated, avoiding the low product selectivity caused by the difficulty in removing the reaction heat, and the poor stability and long life of the catalyst.

[0055] The distribution state of the active component "more outside and less inside" can make the raw materials timely conversion when contacting the catalyst, and quickly desorb, avoiding the diffusion difficulty caused by a large amount of internal reaction, and the low activity and selectivity caused by excessive reaction, and the formation of excessive cracking products to block the pores and cover the active sites.

[0056] The selected carrier and ligand of the present application can anchor the active component during preparation and form a more stable structure with it, to ensure that it can play a catalytic role while not falling off to cause loss and improve economic efficiency. The heat-sensitive ligand can timely convert the ionic active component generated in the reaction process to elemental active component, and quickly re-exert the catalytic effect.

[0057] The allyl acetate catalyst of the present application has suitable position distribution and good activity of each component, which can reduce the amount and loss of active components, improve the overall thermal conductivity and diffusion performance of the catalyst, has the advantages of uniform and firm composition distribution, high strength, good temperature resistance, good thermal conductivity, high space-time yield, high product selectivity, good stability, long catalyst life, etc., and is suitable for synthesizing allyl acetate from acetic acid, oxygen and propylene, and improving economic efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0058] Figure 1 The structure diagram of the catalyst prepared in Example 1 is shown in the figure.

[0059] Figure 2 The structure diagram of the catalyst prepared in Comparative Example 1 is shown in the figure.

[0060] Figure 3 The active component distribution diagram of the catalyst of Example 1 is shown in the figure.

[0061] Figure 4 Activity component distribution map of the catalyst of Comparative Example 1. DETAILED DESCRIPTION

[0062] In order to better illustrate the present application, the present application will be further described below in conjunction with specific embodiments. However, the scope of the present application is not limited only to the scope of these embodiments.

[0063] The source information of the main raw materials used in the examples and comparative examples of the present application is as follows, and other reagent raw materials are all ordinary commercially available products unless otherwise specified:

[0064] Silicon carbide balls: average particle size 2.0 mm, specific surface area 250.5 m 2 / g, pore volume 0.45 cm 3 / g, average pore size 15.0 mm, industrial grade, Shanghai Naoer Nanometer Technology Co., Ltd.;

[0065] Silicon carbide rods: average particle size 2.4 mm, specific surface area 249.6 m 2 / g, pore volume 0.45 cm 3 / g, average pore size 15.0 mm, industrial grade, Shanghai Naoer Nanometer Technology Co., Ltd.;

[0066] Silicon carbide rings: average particle size 2.3 mm, specific surface area 231.0 m 2 / g, pore volume 0.45 cm 3 / g, average pore size 15.0 mm, industrial grade, Shanghai Naoer Nanometer Technology Co., Ltd.;

[0067] Silica gel balls: average particle size 2.0 mm, specific surface area 240.0 m 2 / g, pore volume 0.45 cm 3 / g, average pore size 15.0 mm, industrial grade, Greiner Bio-One International GmbH;

[0068] Graphene pellets: average particle size 2.1 mm, specific surface area 249.8 m 2 / g, pore volume 0.45 cm 3 / g, average pore size 14.9 mm, industrial grade, Henglishengtai (Xiamen) Graphene Technology Co., Ltd.

[0069] The calculation method and test method used in the examples or comparative examples of the present application are as follows:

[0070] 1. The content of each component in the reaction product was analyzed using gas chromatography (chromatograph: Agilent GC 8890A), and the activity and selectivity of the catalyst were calculated according to the following formula:

[0071] Catalyst activity (space-time yield of target product) = amount of allyl acetate produced / catalyst volume / reaction time, unit: g AAC / L Cat . / h;

[0072] Selectivity = (amount of allyl acetate produced / amount of propylene consumed) x 100%;

[0073] Regarding the service life of the catalyst, when the activity of the catalyst (STY value) is 300 g AAC / Lcat. / h, the STY value is less than 300, and it is generally considered that the catalyst activity does not meet the requirements for industrial use.

[0074] 2. Method for measuring specific surface area and pore structure information

[0075] The specific surface area, pore volume and pore size were measured by low-temperature liquid nitrogen physical adsorption method. The specific surface area of the sample was calculated according to the BET theory, and the pore volume and pore size distribution were calculated by t-plot BJH model. The test instrument model was Micromeritics ASAP 2460.

[0076] 3. Method for measuring particle strength

[0077] The particle strength was measured by pressure measurement method, and the detection was based on GB102012-88. The test instrument model was FT-803.

[0078] 4. Method for measuring thermal conductivity

[0079] The thermal conductivity was measured by non-steady-state heat conduction test method, and the detection was based on GB / T10297-2015. The test instrument model was KEM QTM-500.

[0080] 5. Catalyst active component distribution

[0081] The active component distribution was measured by SEM-EDS, and the distribution at the micron scale was observed by a JEOL scanning electron microscope.

[0082] Example 1

[0083] The allyl acetate catalyst was prepared, and the steps were as follows:

[0084] (1) 500 g of an aqueous mixed solution containing 13.8 g of sodium chloropalladate (wherein Pd 5.0 g, 0.05 mol) and 10.6 g of copper chloride (wherein Cu 5.0 g, 0.08 mol) was prepared, 500 g of silicon carbide balls and 5.0 g of isopropyl acrylamide were added thereto, and a complexation reaction was carried out at 20°C for 20 h, and after the completion of the reaction, an aqueous solution of sodium silicate having a concentration of 10 wt% (wherein Na2SiO315.9 g, 0.13 mol) was added, and a precipitation reaction was carried out at 20°C for 20 h, to thereby obtain a reaction solution containing precursor A.

[0085] (2) 6.3 g (0.13 mol) of hydrazine hydrate was added to the reaction solution containing precursor A, and after mixing, a reduction reaction was carried out at 20°C for 10 h, and after washing with warm water at 40°C until no chloride ions were present in the filtrate, drying was carried out at 120°C for 5 h, to thereby obtain precursor B.

[0086] (3) 515.0 g of precursor B was added to 225.7 g of an aqueous potassium acetate solution having a concentration of 10 wt%, and after mixing and impregnation at 20°C for 10 h, drying was carried out at 120°C for 5 h, to thereby obtain finished catalyst 1.

[0087] The structure of catalyst 1 is shown in Figure 1 , and has a "honeycomb" structure, and the internal components are distributed in a manner in which the outer portion is more than the inner portion, and the concentration of the active component decreases by 10 wt% every 10 μm of extension from the shell layer (distribution of the active component is shown in Figure 3 , and the thermal conductivity is shown in Table 1.

[0088] In catalyst 1, the active component Pd was supported at a loading of 1.0 wt% based on the mass of the carrier, the active component Cu was supported at a loading of 1.0 wt%, the ligand isopropyl acrylamide was supported at a loading of 1.0 wt%, and the co-active component potassium acetate was supported at a loading of 1.8 wt%.

[0089] The particle diameter of catalyst 1 was 2.6 mm, the specific surface area was 298 m 2 / g, the pore volume was 0.35 cm 3 / g, and the pore diameter was 13.5 nm.

[0090] Evaluation of the performance of the catalyst:

[0091] Allyl acetate was prepared by the following procedure: 500 mL of catalyst 1 was placed in a fixed bed reactor having an inner diameter of 40 mm and a height of 2000 mm, and inert porcelain balls were packed at both the upper and lower ends, the feed composition was propylene: oxygen: acetic acid: water at a molar ratio of 1:0.3:0.6:0.4, the reaction temperature was 140°C, the reaction pressure was 0.75 MPaG, and the reaction volume space velocity was 1800 h -1 -1. The product after the reaction was condensed and subjected to chromatographic analysis, and the evaluation results are shown in Table 1.

[0092] Example 2

[0093] The catalyst for preparing allyl acetate was prepared by the following steps:

[0094] (1) A 500 g mixed aqueous solution containing 69.0 g of sodium chloropalladate (Pd 25.0 g, 0.23 mol) and 31.7 g of copper chloride (Cu 15.0 g, 0.24 mol) was prepared, 500 g of silicon carbide balls and 50.0 g of isopropyl acrylamide were added thereto, and a coordination reaction was carried out at 30°C for 20 h. After the reaction was completed, a 10 wt% sodium silicate (Na2SiO3 61.1 g, 0.50 mol) aqueous solution was added, and a precipitation reaction was carried out at 20°C for 20 h to obtain a precursor A.

[0095] (2) 66.1 g (1.32 mol) of hydrazine hydrate was added to the reaction solution containing the precursor A and mixed uniformly, and a reduction was carried out at 20°C for 10 h. After washing with warm water at 40°C until there was no chloride ion in the filtrate, drying was carried out at 120°C for 5 h to obtain a precursor B.

[0096] (3) 590.0 g of the precursor B was added to 376.1 g of a 10 wt% potassium acetate aqueous solution, and mixed and impregnated at 20°C for 20 h. After drying at 120°C for 5 h, a finished catalyst 2 was obtained.

[0097] The catalyst 2 had a "honeycomb" structure, and the internal components were distributed in a "more outside and less inside" manner. As the active component extended inward from the shell layer by 10 μm, the concentration of the active component was reduced by 13 wt%. The thermal conductivity coefficient is shown in Table 1.

[0098] In the catalyst 2, the active component Pd was loaded at 5.0 wt% based on the mass of the support, the active component Cu was loaded at 3.0 wt%, the ligand isopropyl acrylamide was loaded at 10.0 wt%, and the co-active component potassium acetate was loaded at 3.0 wt%.

[0099] The particle size of the catalyst 2 was 2.9 mm, the specific surface area was 325 m 2 / g, the pore volume was 0.42 cm 3 / g, and the pore diameter was 14.0 nm.

[0100] Evaluation of the performance of the catalyst:

[0101] The allyl acetate was prepared by the following steps: 500 mL of the catalyst 1 was put into a fixed bed reactor having an inner diameter of 40 mm and a height of 2000 mm, and inert porcelain balls were packed at the upper and lower ends. The feed composition was propylene: oxygen: acetic acid: water at a molar ratio of 1:0.4:0.6:0.5, the reaction temperature was 140°C, the reaction pressure was 0.65 MPaG, the reaction volume space velocity was 1800 h -1The product after reaction was condensed and analyzed by chromatography, and the evaluation results are shown in Table 1.

[0102] Example 3

[0103] The preparation of allyl acetate catalyst is as follows:

[0104] (1) 500 g of a mixed aqueous solution containing 27.6 g of sodium chloropalladate (Pd 10.0 g, 0.09 mol) and 69.0 g of chloroauric acid (Au 40.0 g, 0.20 mol) was prepared, 500 g of silicon carbide rings and 25.0 g of trispyridine sodium chloride were added, and a coordination reaction was carried out at 25°C for 40 h. After the reaction was completed, a 10 wt% sodium carbonate (Na2CO3 30.7 g, 0.29 mol) aqueous solution was added, and a precipitation reaction was carried out at 20°C for 20 h to obtain precursor A.

[0105] (2) 66.1 g (1.32 mol) of hydrazine hydrate was added to the reaction solution containing precursor A and mixed uniformly, and after reduction at 20°C for 10 h, 40°C warm water was used for washing until there was no chloride ion in the filtrate. After washing was completed, drying was carried out at 120°C for 5 h to obtain precursor B.

[0106] (3) 575.0 g of precursor B was added to 125.4 g of a 10 wt% potassium acetate aqueous solution, and mixed and impregnated at 20°C for 20 h. Drying was carried out at 120°C for 5 h to obtain finished catalyst 3.

[0107] Catalyst 3 has a "honeycomb" structure, and the internal components are distributed in a "more outside and less inside" manner. The concentration of the active component decreases by 12 wt% every 10 μm of extension from the shell layer, and the thermal conductivity is shown in Table 1.

[0108] In catalyst 3, based on the mass of the carrier, the active component Pd loading is 2.0 wt%, the active component Au loading is 8.0 wt%, the ligand trispyridine sodium chloride loading is 5.0 wt%, and the active component potassium acetate loading is 1.0 wt%.

[0109] The particle size of catalyst 3 is 2.5 mm, the specific surface area is 280 m 2 / g, the pore volume is 0.38 cm 3 / g, and the pore size is 12.8 nm.

[0110] Catalyst performance evaluation:

[0111] The allyl acetate was prepared by the following steps: 500 mL of catalyst 1 was put into a fixed bed reactor with an inner diameter of 40 mm and a height of 2000 mm, and inert porcelain balls were filled at the upper and lower ends, the feed composition was propylene: oxygen: acetic acid: water in a molar ratio of 1:0.5:0.5:0.5, the reaction temperature was 140°C, the reaction pressure was 0.85 MPaG, and the reaction volume space velocity was 1800 h -1 After the reaction product was condensed, it was subjected to chromatographic analysis, and the evaluation results are shown in Table 1.

[0112] Example 4

[0113] The allyl acetate catalyst was prepared by the following steps:

[0114] (1) A mixed aqueous solution containing 31.7 g of copper chloride (Cu 15.0 g, 0.24 mol) and 69.0 g of chloroauric acid (Au 35.0 g, 0.18 mol) was prepared at 500 g, and 500 g of silicon carbide rings and 25.0 g of (4,4'-di-tert-butyl-2,2'-bipyridine) bis[(2-pyridyl)phenyl] sodium were added, and a coordination reaction was carried out at 30°C for 20 h, and after the reaction was completed, a 10 wt% sodium hydroxide (NaOH 84.1 g, 2.10 mol) aqueous solution was added, and a precipitation reaction was carried out at 20°C for 40 h to obtain precursor A.

[0115] (2) 66.1 g (1.32 mol) of hydrazine hydrate was added to the reaction solution containing precursor A and mixed uniformly, and after reduction at 20°C for 10 h, 40°C warm water was used for washing until there was no chloride ion in the filtrate, and after the washing was completed, drying was carried out at 120°C for 5 h to obtain precursor B.

[0116] (3) 575.0 g of precursor B was added to 125.4 g of a 10 wt% potassium acetate aqueous solution, and mixed and impregnated at 20°C for 20 h, and dried at 120°C for 5 h to obtain finished catalyst 3.

[0117] Catalyst 4 has a "honeycomb" structure, and the internal components are distributed in a "more outside and less inside" manner, and the concentration of the active component decreases by 11 wt% every 10 μm of the active component extending inward from the shell layer, and the thermal conductivity is shown in Table 1.

[0118] In catalyst 4, the active component Cu loading based on the carrier mass is 3.0 wt%, the active component Au loading is 7.0 wt%, the ligand (4,4'-di-tert-butyl-2,2'-bipyridine) bis[(2-pyridyl)phenyl] sodium loading is 5.0 wt%, and the active component potassium acetate loading is 1.0 wt%.

[0119] The particle size of catalyst 4 is 2.8 mm, the specific surface area is 310 m 2 / g, and the pore volume is 0.39 cm3 / g, and the pore diameter was 14.1 nm.

[0120] Evaluation of catalyst performance:

[0121] Allyl acetate was prepared by the following steps: 500 mL of catalyst 1 was put into a fixed bed reactor with an inner diameter of 40 mm and a height of 2000 mm, and inert porcelain balls were filled at the upper and lower ends. The feed composition was propylene: oxygen: acetic acid: water in a molar ratio of 1:0.7:0.8:0.9, the reaction temperature was 140°C, the reaction pressure was 0.75 MPaG, the reaction volume space velocity was 1800 h -1 , and the product after reaction was condensed and subjected to chromatographic analysis. The evaluation results are shown in Table 1.

[0122] Example 5

[0123] The catalyst for preparing allyl acetate was prepared by the following steps:

[0124] (1) A mixed aqueous solution containing 27.6 g of sodium chloropalladate (Pd 10.0 g, 0.09 mol) and 69.0 g of chloroauric acid (Au 40.0 g, 0.20 mol) was prepared at 500 g, and 500 g of silicon carbide rods and 25.0 g of a heat-sensitive hydrogel were added thereto. The coordination reaction was carried out at 25°C for 40 h, and after the reaction was completed, a 10 wt% sodium carbonate (Na2CO3 30.7 g, 0.29 mol) aqueous solution was added, and a precipitation reaction was carried out at 20°C for 20 h to obtain precursor A.

[0125] (2) Hydrogen gas (0.002 mol / min) with a volume concentration of 5 vol% was introduced into the reaction solution containing precursor A at a gas velocity of 1 L / min, and reduction was continued at 20°C for 10 h to obtain precursor B.

[0126] (3) 575.0 g of precursor B was added to 125.4 g of a 10 wt% potassium acetate aqueous solution, and mixed and impregnated at 20°C for 20 h, and dried at 120°C for 5 h to obtain finished catalyst 5.

[0127] Catalyst 5 had a "honeycomb" structure, and the internal components were distributed in a "more outside and less inside" manner. The concentration of the active component decreased by 20 wt% for every 10 μm of extension of the active component from the shell layer, and the thermal conductivity coefficient is shown in Table 1.

[0128] In catalyst 5, the active component Pd loading was 2.0 wt% based on the carrier mass, the active component Au loading was 8.0 wt%, the ligand heat-sensitive hydrogel loading was 5.0 wt%, and the active component potassium acetate loading was 1.0 wt%.

[0129] The particle size of catalyst 5 was 2.9 mm, the specific surface area was 301 m 2 / g, the pore volume is 0.36 cm 3 / g, the pore size is 13.1 nm.

[0130] Evaluation of catalyst performance:

[0131] Allyl acetate was prepared by the following steps: 500 mL of catalyst 1 was put into a fixed bed reactor with an inner diameter of 40 mm and a height of 2000 mm, and inert porcelain balls were filled at the upper and lower ends. The feed composition was propylene: oxygen: acetic acid: water in a molar ratio of 1:0.8:0.6:0.7, the reaction temperature was 140°C, the reaction pressure was 0.70 MPaG, the reaction volume space velocity was 1800 h -1 After the reaction product was condensed, it was analyzed by chromatography, and the evaluation results are shown in Table 1.

[0132] Comparative Example 1

[0133] Allyl acetate catalyst was prepared by the method of Reference Example 1, except that in step (1) the silicon carbide balls were replaced by silica gel balls, and the other operations and conditions were unchanged, to obtain a catalyst (structure as Figure 2 , active component distribution as Figure 4 ), and the performance evaluation results are shown in Table 1.

[0134] Comparative Example 2

[0135] Allyl acetate catalyst was prepared by the method of Reference Example 1, except that in step (1) the silicon carbide balls were replaced by graphene balls, and the other operations and conditions were unchanged, to obtain a catalyst, and the performance evaluation results are shown in Table 1.

[0136] Comparative Example 3

[0137] Allyl acetate catalyst was prepared by the method of Reference Example 1, except that in step (1) the potassium acetate was replaced by magnesium acetate, and the other operations and conditions were unchanged, to obtain a catalyst, and the performance evaluation results are shown in Table 1.

[0138] Comparative Example 4

[0139] Allyl acetate catalyst was prepared by the method of Reference Example 1, except that in step (1) the potassium acetate was replaced by potassium nitrate, and the other operations and conditions were unchanged, to obtain a catalyst, and the performance evaluation results are shown in Table 1.

[0140] Comparative Example 5

[0141] Allyl acetate catalyst was prepared by the method of Reference Example 1, except that in step (2) no ligand was added, and the other operations and conditions were unchanged, to obtain a catalyst, and the performance evaluation results are shown in Table 1.

[0142] Comparative Example 6

[0143] The allyl acetate catalyst was prepared according to the method in Example 1, except that the ligand was replaced with triphenylphosphine in step (2), while other operations and conditions remained unchanged. The catalyst was obtained and the performance evaluation results are shown in Table 1.

[0144] Table 1. Initial activity and lifetime evaluation results of different catalysts

[0145]

[0146] Depend on Figure 1 The data shows that the method of the present invention prepares a solution containing an active component metal salt, coordinates it with a ligand, mixes it with a carrier and loads it, and after precipitation and reduction, prepares a solution of the auxiliary metal salt for precipitation and impregnation to obtain an allyl acetate catalyst with an overall "honeycomb" structure and an internal component distribution of "more on the outside and less on the inside".

[0147] As can be seen from the data in Table 1, the catalyst prepared by this invention has the characteristics of uniform and firmly anchored composition, high dispersion of active components, good thermal conductivity, high space-time yield, high product selectivity, and good stability. It is suitable for the synthesis of allyl acetate from acetic acid, oxygen, and propylene.

Claims

1. A supported allyl acetate catalyst, characterized by, The catalyst contains a carrier, and an active component, a ligand, and an auxiliary active component supported on the carrier; The carrier is a silicon carbide material with a particle size of 2-3 mm; The active component is at least one of metal Pd and Cu; The auxiliary active component is at least one of alkali metal acetate; The ligand is isopropyl acrylamide; The active component loading is 1-10.0 wt%, the auxiliary active component loading is 1.0-5.0 wt%, and the ligand loading is 0.1-10.0 wt%, based on the carrier mass; The preparation method of the supported allyl acetate catalyst comprises the following steps: (1) preparing a solution containing an active component metal salt, then adding a carrier and a ligand for coordination reaction, and then adding a precipitant for precipitation reaction to obtain a reaction solution containing precursor A; (2) adding a reducing agent to the reaction solution of step (1) for reduction reaction, and then washing and drying to obtain precursor B; (3) dipping precursor B of step (2) into a solution containing an auxiliary active component, and then drying after taking out to obtain a supported allyl acetate catalyst.

2. The supported allyl acetate catalyst according to claim 1, characterized in that, The auxiliary active component is sodium acetate and / or potassium acetate.

3. The supported allyl acetate catalyst according to claim 1, wherein The silicon carbide material is at least one of silicon carbide balls, silicon carbide rods, and silicon carbide rings.

4. The supported allyl acetate catalyst of claim 1, wherein, The allyl acetate catalyst has a particle size of 2-3 mm, a specific surface area of 200-600 m 2 / g, a pore volume of 0.2-0.6 cm 3 / g, and a pore size of 10-15 nm. The allyl acetate catalyst has a "honeycomb" structure, and the internal components are distributed in a "more outside and less inside" manner.

5. The supported allyl acetate catalyst according to claim 4, wherein The allyl acetate catalyst has a concentration reduction of 10-20 wt% for every 10 μm of the active component extending inward from the shell layer.

6. A process for the preparation of the supported allyl acetate catalyst according to any one of claims 1 to 5, characterized in that the steps It comprises: (1) preparing a solution containing an active component metal salt, then adding a carrier and a ligand for coordination reaction, and then adding a precipitant for precipitation reaction to obtain a reaction solution containing precursor A; (2) adding a reducing agent to the reaction solution of step (1) for reduction reaction, and then washing and drying to obtain precursor B; (3) dipping precursor B of step (2) into a solution containing an auxiliary active component, and then drying after taking out to obtain a supported allyl acetate catalyst.

7. The process for preparing a supported allyl acetate catalyst according to claim 6, characterized by, In step (1), the solution containing an active component metal salt is an aqueous solution with a concentration of 10-20 wt%; The active component metal salt is at least one of Pd, Cu chloride salt, nitrate salt, and acetate salt; In step (1), the carrier is a silicon carbide material; The silicon carbide material has a particle size of 2-3 mm; In step (1), the mass ratio of the solution containing an active component metal salt to the carrier is 1:2-50, based on the metal salt in the solution; In step (1), the ligand is isopropyl acrylamide; The mass ratio of the ligand to the carrier is 1:10-100; In step (1), the precipitant is at least one of potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, potassium silicate, and sodium silicate; The amount of the precipitant is 1-20 times the molar amount of the metal in the solution containing an active component metal salt.

8. The preparation method of the supported allyl acetate catalyst according to claim 7, characterized in that, The silicon carbide material is at least one of silicon carbide balls, silicon carbide rods, and silicon carbide rings.

9. The preparation method of the supported allyl acetate catalyst according to claim 7, characterized in that, The amount of the precipitant is 1-5 times the molar amount of the metal in the solution containing an active component metal salt.

10. The process for preparing a supported allyl acetate catalyst according to claim 7, characterized by, The precipitant is prepared as an aqueous solution with a concentration of 1-20 wt%.

11. The process for preparing a supported allyl acetate catalyst according to claim 10, characterized in that, The precipitant is prepared as an aqueous solution with a concentration of 5-10 wt%.

12. The method of claim 6, wherein, In step (1), the complexing reaction is carried out at a temperature of 10-50°C for 10-72 hours. In step (1), the precipitating reaction is carried out at a temperature of 10-50°C for 10-72 hours.

13. The method of claim 12, wherein, The complexing reaction is carried out at a temperature of 20-30°C for 20-40 hours.

14. The method of claim 12, wherein, The precipitating reaction is carried out at a temperature of 20-30°C for 20-40 hours.

15. The preparation method according to claim 6, characterized in that, In step (2), the reducing agent is selected from at least one of ethylene, propylene, hydrogen, hydrazine hydrate and formaldehyde. The amount of the reducing agent added is 0.5-20 times the molar amount of the metal in the active component-containing metal salt solution in step (1). In step (2), the reducing reaction is carried out at a temperature of 10-50°C for 5-40 hours. In step (2), the drying is carried out at a temperature of 100-150°C for 2-10 hours.

16. The method of claim 15, wherein, The amount of the reducing agent added is 1-15 times the molar amount of the metal in the active component-containing metal salt solution in step (1).

17. The preparation method according to claim 15, characterized in that, The reducing reaction is carried out at a temperature of 20-30°C for 10-20 hours.

18. The method of claim 6, wherein, In step (3), the solution containing the promoter component is an aqueous solution with a concentration of 1-20 wt%. The promoter component is selected from at least one of alkali metal acetate. The mass ratio of the precursor B to the solution containing the promoter component is 1:0.1-20. In step (3), the impregnation is carried out at a temperature of 10-50°C for 5-36 hours. In step (3), the drying is carried out at a temperature of 100-150°C for 2-10 hours.

19. The method of claim 18, wherein, The solution containing the promoter component is an aqueous solution with a concentration of 5-10 wt%.

20. The method of claim 18, wherein, The promoter component is potassium acetate.

21. The method of claim 18, wherein, The mass ratio of the precursor B to the solution containing the promoter component is 1:0.2-10.

22. Use of the supported allyl acetate catalyst of any one of claims 1-5 or prepared by the method of any one of claims 6-21 in the preparation of allyl acetate.

23. A process for the preparation of allyl acetate, characterized by, The steps include: allyl acetate is prepared by mixing propylene, oxygen, acetic acid and water in the presence of the supported allyl acetate catalyst of any one of claims 1-5 or prepared by the method of any one of claims 6-21 in a fixed bed reactor; The molar ratio of propylene to oxygen, acetic acid and water is 1:0.3-1:0.2-1:0.3-1. The reaction is carried out at a temperature of 120-180°C and a pressure of 0.6-0.9 MPaG, with a reaction volume space velocity of 1500-2500 h -1 .

24. The method for preparing allyl acetate according to claim 23, characterized in that, The reaction is carried out at a temperature of 140-170°C and a pressure of 0.65-0.85 MPaG.

25. The method for preparing allyl acetate according to claim 23, characterized in that, The reaction volume space velocity is 1800-2000h -1 .

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