Catalyst for preparing acrylic acid / acrylate by one-step method and preparation method thereof

Abstract

The one-step method for preparing acrylic acid / acrylate comprises the following steps: taking methanol and acetic acid as raw materials, or methanol and methyl acetate as raw materials, and reacting at the temperature of 300-450 DEG C under the action of a catalyst to obtain acrylic acid or acrylate, the catalyst comprises vanadium, phosphorus, oxygen elements and a second metal; the second metal comprises a metal element M1 and / or a metal element M2, the metal element M1 comprises one or more than two metal elements selected from Pt, Pd, Ru, Rh, Ti, W, Zr, Ce, La, Zn, Mo and Nb, and the metal element M2 comprises one or more than two metal elements selected from Li, Na, K, Rb, Cs, Mg, Ca, Sr and Ba. According to the method, the acrylic acid / methyl acrylate catalyst is prepared from cheap raw materials, and the catalytic performance is stable.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for preparing acrylic acid / acrylate, in particular to a catalyst for preparing acrylic acid / acrylate in one step and a method for synthesizing acrylic acid / acrylate. BACKGROUND

[0002] Acrylic acid is an important chemical raw material, which is widely used in super absorbent resin (SAP), coatings and adhesives and other fields. Driven by the demand for downstream products SAP and acrylate, the global consumption of acrylic acid is increasing year by year.

[0003] There are several methods for producing acrylic acid, such as cyanethanol method, acetylene carbonylation method, acrylonitrile hydrolysis method and propylene oxidation method. The first three methods have been gradually eliminated due to the reasons of more industrial "three wastes", high cost, and part of the raw materials are highly toxic. At present, the two-step oxidation method of propylene is mainly used in the world, in which propylene is first oxidized to propylene aldehyde, and then propylene aldehyde is oxidized to acrylic acid. The raw material of this method mainly comes from petroleum, and the cost is high. The production process of two-step method is complex. The coal chemical industry in China is developing rapidly, which makes the production capacity of acetic acid and methanol grow too fast, while the demand growth is relatively slow. It is urgent to develop downstream products of acetic acid and methanol and extend the industrial chain and value chain. Therefore, it is of great practical significance to develop a green and low-carbon synthesis route of acrylic acid with independent intellectual property rights from coal chemical products, which is in line with the national conditions of "rich in coal, lack of oil and gas" in China.

[0004] The preparation of acrylic acid from coal-based formaldehyde and acetic acid through aldol condensation reaction conforms to the policy of green chemical industry in China. Compared with the propylene oxidation method, it not only reduces the raw material cost, but also reduces the dependence on petroleum resources in the production of acrylic acid. As one of the important raw materials of the aldol condensation method of formaldehyde and acetic acid, the main sources of formaldehyde include formaldehyde aqueous solution (37%), tri / multi-formaldehyde, etc. Among them, the concentration of formaldehyde aqueous solution is low, which increases the cost of raw material concentration and product separation; the cost of polyformaldehyde is high, and it needs to be depolymerized at high temperature before use, which increases the production cost. Compared with formaldehyde aqueous solution and polyformaldehyde, methanol can be oxidized to formaldehyde, and then condensed with acetic acid. Not only does it avoid the introduction of excess water, but also it reduces the cost of raw materials. However, the two-step process of oxidation and aldol condensation has a long process flow at the present stage, which increases the operation cost.

[0005] Chinese Patent Application Publication No. 118142515A discloses a catalyst for preparing methyl methacrylate, wherein a, b, and c are the weight ratios of active components Mg, Si, and X, respectively, and d is the stoichiometric ratio of O atoms. Based on the mass of magnesium oxide (MgO), the mass fraction of Si is 20-500%, and the mass fraction of X is 0.1-100%, wherein X is selected from one or more of Mn, Fe, Ni, Co, Cu, Cr, Zn, Cs, Mo, W, Cd, P, Al, Na, and K. The method for preparing methyl methacrylate uses methanol and methyl acetate as raw materials to synthesize methyl methacrylate in a one-step process.

[0006] Developing catalysts with stable and efficient catalytic performance, and using inexpensive raw materials to prepare methyl acrylate / acrylic acid in a one-step process, has a significant competitive advantage. Summary of the Invention

[0007] One object of the present invention is to provide a catalyst for the one-step preparation of acrylic acid / methyl acrylate from inexpensive raw materials, which has stable catalytic performance.

[0008] Another objective of this invention is to prepare acrylic acid / methyl acrylate from inexpensive raw materials in one step using the catalyst of this application, with high selectivity for acrylic acid / methyl acrylate.

[0009] A catalyst for the one-step preparation of acrylic acid / methyl acrylate comprises vanadium, phosphorus, oxygen, and a second metal; the second metal comprises metal element M1 and / or metal element M2, wherein metal element M1 comprises one or more metal elements selected from Pt, Pd, Ru, Rh, Ti, W, Zr, Ce, La, Zn, Mo, and Nb, and metal element M2 comprises one or more metal elements selected from Li, Na, K, Rb, Cs, Mg, Ca, Sr, and Ba.

[0010] In a catalyst, the active phase of the metal element M1 may be a metallic state, an oxidized state, or a mixture of metal and oxide.

[0011] The catalyst of this invention is applied to a reaction system for the one-step preparation of acrylic acid / methyl acrylate. The catalyst has high stability and high selectivity for acrylic acid / methyl acrylate.

[0012] In the one-step preparation of acrylic acid / methyl acrylate reaction system, methanol and acetic acid / acetic acid ester are used as raw materials. Under the action of the above catalyst, the reaction temperature is controlled at 300-450℃ to obtain acrylic acid / methyl acrylate. Detailed Implementation

[0013] The method for preparing acrylic acid / methyl acrylate in one step according to this application and the catalyst used are described in further detail below. This does not limit the scope of protection of this application, which is defined by the claims. Certain specific details disclosed provide a full understanding of the various disclosed embodiments. However, those skilled in the art will recognize that embodiments can be implemented without employing one or more of these specific details, but using other materials, etc.

[0014] Unless the context otherwise requires, the terms “comprising” and “including” in the specification and claims shall be understood as open-ended and inclusive, meaning “including, but not limited to”.

[0015] In this specification, the range of values ​​referred to as "value A to value B" refers to the range including the endpoint values ​​A and B.

[0016] In this specification, the numerical range indicated by "above" or "below" refers to the numerical range that includes the stated number.

[0017] The terms "implementation," "an implementation / preferred implementation," "another implementation / preferred implementation," or "certain implementations" used in this specification refer to specific elements described in relation to the implementation (e.g., specific features, structures, or characteristics) included in at least one implementation. Therefore, "implementation," "an implementation," "another implementation," or "certain implementations" do not necessarily all refer to the same implementation. Furthermore, specific features, structures, or characteristics can be combined in any way within one or more implementations. Each feature disclosed in this specification can be replaced by any alternative feature that provides the same, equivalent, or similar purpose. Therefore, unless otherwise specified, the disclosed features are merely general examples of equivalent or similar features.

[0018] Unless otherwise specified, experimental methods in the following examples are generally performed under standard conditions or as recommended by the manufacturer. Unless otherwise stated, all percentages, ratios, proportions, or parts are by weight.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as are familiar to one skilled in the art. Furthermore, any methods and materials similar to or equivalent to those described herein may be used in the methods of this application. The preferred embodiments and materials described herein are for illustrative purposes only.

[0020] This invention aims to provide a catalyst and reaction method for a one-step synthesis of acrylic acid / acrylate using methanol and acetic acid / acetic acid esters as raw materials. Compared with traditional synthesis methods, this production route has the following advantages: First, the methanol and acetic acid raw materials used in this process are inexpensive and readily available, while reducing dependence on petroleum resources; second, the in-situ dehydrogenation of methanol to formaldehyde further reduces raw material costs and realizes high-value utilization of methanol; third, the one-step reaction of methanol dehydrogenation and aldol condensation shortens the process flow and reduces process costs.

[0021] Definition: "Space velocity" is the mass of feedstock processed per unit mass of catalyst per unit time, expressed in g / (g catalyst·h), which can be simplified to h. -1 .

[0022] "mL / min / g cat" refers to the flow rate of oxygen-containing gas per unit mass of catalyst.

[0023] A catalyst for the one-step production of acrylic acid / acrylate includes vanadium, phosphorus, oxygen, and a second metal; the second metal includes metal element M1 and / or metal element M2, metal element M1 includes one or more metal elements selected from Pt, Pd, Ru, Rh, Ti, W, Zr, Ce, La, Zn, Mo, and Nb, and metal element M2 includes one or more metal elements selected from Li, Na, K, Rb, Cs, Mg, Ca, Sr, and Ba.

[0024] By introducing metal element M1 and / or metal element M2 into the VPO catalyst, the stability of the catalyst in the one-step preparation of acrylic acid / acrylate reaction system and the selectivity of acrylic acid / acrylate can be improved.

[0025] In some embodiments, the second metal includes metal element M1 or metal element M2.

[0026] The metallic element M1 is selected from one or more metallic elements selected from Pt, Pd, Ru, Rh, W, Zr, Ce, La, Zn, Mo, and Nb.

[0027] The metallic element M2 is selected from one or more metallic elements from Na, K, Cs, Mg, Ca, and Ba.

[0028] The molar ratio of phosphorus, vanadium, and metal M1 is (0.5-2):1:(0.01-10).

[0029] The molar ratio of phosphorus, vanadium, and metal M2 is (0.5-2):1:(0.01-10).

[0030] Optionally, the molar ratio of phosphorus, vanadium and metal M1 is (0.8-1.6) / 1 / (0.1-1).

[0031] The molar ratio of phosphorus, vanadium and metal M2 is (0.8-1.6) / 1 / (0.1-1).

[0032] In some embodiments, the metal element M1 is selected from one or more metal elements selected from W, Ce, La, Zn, and Mo.

[0033] The metallic element M2 is selected from one or more metallic elements among Na, K, Cs, Ca, and Ba.

[0034] Optionally, the metallic element M1 is selected from one or two metallic elements from La, Zn, and Mo.

[0035] In some embodiments, the second metal includes metal element M1 and metal element M2.

[0036] Metal element M1 is selected from one or more of the following metal elements: Ti, W, Ce, La, Zn, and Mo. Metal element M2 is selected from one or more of the following metal elements: Na, K, Ba, and Cs.

[0037] When both M1 and M2 are included in the catalyst, the catalyst has stronger dehydrogenation activity, which can enhance the methanol dehydrogenation process, enhance the aldol condensation process, inhibit coking, and improve stability.

[0038] M1 / M2 may exist in a metallic state and / or an oxidized state.

[0039] The catalysts M1 metal and / or M2 metal introduced into the VPO structure in this application exhibit excellent stability in the reaction system for preparing acrylic acid / acrylate from methanol and acetic acid / acetic acid ester. They maintain relatively high conversion rate and selectivity even after long-term use.

[0040] The catalyst described above can be prepared using any method available in the art. Preferably, it is prepared using the following method.

[0041] A one-step method for preparing a catalyst for the production of acrylic acid / acrylate includes: 1) mixing V2O5 in a mixture of fatty alcohol / benzyl alcohol at a temperature of 90-150℃; 2) after cooling the mixture obtained in step 1), adding metal element M1 and / or metal element M2 precursors and phosphoric acid, and mixing thoroughly to obtain a suspension; 3) after filtering, washing, drying and calcining the suspension in step 2), the catalyst is obtained.

[0042] Fatty alcohols are low-carbon fatty alcohols, such as isobutanol and / or n-butanol.

[0043] In some embodiments, the volume ratio of isobutanol to benzyl alcohol is 1:1 to 4:1.

[0044] In a mixed solvent of fatty alcohols / benzyl alcohol (e.g., isobutanol and benzyl alcohol), V2O5 is used to... 5+ Reduced to vanadium ion intermediates (e.g., containing V) 4+ The substance (of which) eventually reacts with the added P source to generate a hemihydrated precursor.

[0045] The amount of mixed solvent is unlimited, and it is possible to increase the V of V₂O₅. 5+ Restore to V 4+ Therefore, the amount of mixed solvent can be excessive.

[0046] V2O5 was refluxed and mixed in the above-mentioned ratio of isobutanol / benzyl alcohol mixed solvent at a temperature of 90-150℃.

[0047] The reflux time is 2-10 hours.

[0048] Under conditions of 90-150℃, V2O5 in the above-mentioned ratio of isobutanol / benzyl alcohol mixed solvent can cause vanadium pentoxide to form a vanadium ion intermediate to participate in the reaction in step 2).

[0049] In some embodiments, in step 2), the mixture of step 1), the precursors of metal element M1 and / or metal element M2, and phosphoric acid are mixed at 50-80°C.

[0050] Phosphoric acid can be used in a solution with a mass concentration of approximately 85 wt%.

[0051] Alternatively, in step 2), several substances are refluxed, mixed, and stirred for 8-20 hours.

[0052] Step 2) Mix at a temperature of 50-80℃, allowing metal element M1 and / or metal element M2 to fully react with other substances to form a precipitate, which is more uniformly dispersed on the VPO structure. After drying and calcination, the catalyst obtained has better stability of catalytic performance in the reaction system for preparing acrylic acid / acrylate.

[0053] In steps 1) and 2) of this invention, the amounts of V₂O₅, metal element M1 and / or metal element M2 precursors, and phosphoric acid are basically consistent with the molar ratios of PV-M1 and PV-M2 elements in the aforementioned catalyst. The molar ratios of the various substances in the catalyst obtained through subsequent processing are consistent with the amounts added during preparation. Further details are omitted here.

[0054] Precursors of metal element M1 and / or metal element M2 are usually inorganic soluble metal salts, such as acetates, nitrates, ammonium salts, etc.

[0055] In some embodiments, the drying temperature in step 3) is 80-140°C.

[0056] The drying time is not limited, but the solvent content in the solid is controlled to be below a certain level. Optionally, drying can be carried out at a temperature of 80-140℃ for 1-24 hours.

[0057] The dried catalyst precursor was calcined in air at 350-650℃ to obtain the catalyst.

[0058] Optionally, the roasting temperature can be controlled between 420-550℃.

[0059] Calcination time: 5-15 hours.

[0060] The catalyst prepared by the above method has a thinner sheet shape and more exposed active sites, which is beneficial to improving catalytic activity.

[0061] On the other hand, a one-step method for preparing acrylic acid / acrylate includes: using methanol and acetic acid as raw materials, or methanol and ester acetate as raw materials, or methanol, acetic acid, and ester acetate as raw materials, reacting under the action of the above-mentioned catalyst at a temperature of 300-450°C to obtain acrylic acid / acrylate.

[0062] The acetate can be one or a mixture of two or more of methyl acetate, ethyl acetate, propyl acetate, and butyl acetate.

[0063] Preferably, the reaction temperature is between 350-450℃.

[0064] During the reaction, the pressure is 0.01-0.5 MPa (absolute pressure); preferably, the pressure is 0.05-0.2 MPa (absolute pressure).

[0065] Under these conditions, methanol and acetic acid (or acetic acid ester) undergo oxidation and aldol condensation reactions to ultimately yield acrylic acid / acrylate.

[0066] In some embodiments, the molar ratio of acetic acid to methanol is (0.1-2):1; preferably, the molar ratio of acetic acid to methanol is (0.2-1):1.

[0067] The molar ratio of acetate to methanol is (0.1-2):1; preferably, the molar ratio of acetate to methanol is (0.2-1):1.

[0068] In some embodiments, the feedstock is premixed by gasification outside the reactor, and the mass hourly space velocity (MSV) of the mixed gas is 0.1-2.5 h⁻¹. -1Preferably, the mass hourly space velocity (MHSV) is 0.2-1.0 h⁻¹. -1 .

[0069] Optionally, the mass hourly space velocity (MSV) of the gas mixture is 0.5-1.0 h⁻¹. -1 .

[0070] During the reaction of methanol and acetic acid, or methanol and acetic acid esters, oxygen-containing gas, such as air, is continuously introduced.

[0071] The oxygen-containing gas flow rate (e.g., air flow rate) is 2-100 mL / min / g cat; preferably, the oxygen-containing gas flow rate is 5-50 mL / min / g cat.

[0072] The catalyst of this application is used in a one-step process for producing acrylic acid / acrylate (acrylic acid and acrylate). The catalyst can operate for a long time and has a good catalytic effect. The resulting product, acrylic acid / acrylate, has high selectivity and high conversion rate of acetic acid or acrylate.

[0073] In addition, compared with the prior art, the one-step method for producing acrylic acid / acrylate of the present invention has the following advantages: First, the methanol and acetic acid raw materials used in this process are inexpensive and readily available, while reducing dependence on petroleum resources; second, the in-situ dehydrogenation of methanol to formaldehyde further reduces the cost of raw materials and realizes the high-value utilization of methanol; third, the one-step reaction of methanol dehydrogenation and aldol condensation coupling shortens the process flow and reduces process costs.

[0074] The following specific examples further illustrate the one-step method for producing acrylic acid / acrylate, but these are not intended to limit the scope of protection of this invention. In the following examples and comparative examples, the conversion rate and selectivity are calculated as follows.

[0075] The formulas for calculating the conversion rate of acetate / acetic acid ester and the selectivity of acrylic acid / acrylate ester are as follows:

[0076] X(%)=(N in -N out ) / N in ×100%

[0077] S(%) = N AA / MA,out / (N AA / MA,out +∑N byproduct) ×100%

[0078] Where X (%) represents the conversion rate of acetate / acetic acid ester; S (%) represents the selectivity of acrylic acid / acrylate ester; N in The molar amount of acetic acid / acetic acid ester entering the reactor; N out The molar amount of acetic acid / acetic acid ester flowing out of the reactor; N AA / MA,out∑N represents the molar amount of acrylic acid / acrylate in the product concentration; byproduct It is the molar amount of all byproducts.

[0079] The catalysts for the one-step production of acrylic acid / acrylate from M1(M2)-VPO methanol and acetic acid / acetic acid ester were evaluated on a fixed-bed microreactor. The preparation methods and reaction conditions of different catalysts are described in Examples 1-10. The conversion rate and selectivity are values ​​obtained by sampling after 0.5 hours of reaction.

[0080] Example 1:

[0081] 7.5 g of V₂O₅ was added to a mixture of isobutanol / benzyl alcohol (50 mL: 25 mL), and the mixture was stirred and refluxed at 110 °C for 6 h. After cooling to 70 °C, 4.9 g of zinc nitrate and 9.5 g of phosphoric acid (85 wt%) were added, and the mixture was stirred and refluxed for 16 h to obtain a suspension. The resulting suspension was filtered and then dried at 110 °C to obtain the desired catalyst precursor. The catalyst precursor was calcined in air at 500 °C for 10 h to obtain the catalyst.

[0082] During the microreactor evaluation, the catalyst loading was 3g, the reaction temperature was 380℃, the pressure was 0.1MPa (absolute pressure), the acetic acid / methanol feed molar ratio was 0.5 / 1, and the mass hourly space velocity (HHSV) was 0.8h. -1 The air flow rate was 60 mL / min. Catalyst evaluation results showed that the acetic acid conversion rate was 50.2 wt%, and the selectivity for acrylic acid and methyl acrylate was 45.2 wt%.

[0083] Example 2:

[0084] 7.5 g of V₂O₅ was added to a mixture of isobutanol / benzyl alcohol (40 mL:40 mL), and the mixture was stirred and refluxed at 120 °C for 8 h. After cooling to 60 °C, 10.2 g of ammonium molybdate and 7.6 g of phosphoric acid (85 wt%) were added, and the mixture was stirred and refluxed for 18 h to obtain a suspension. The resulting suspension was filtered and then dried at 100 °C to obtain the desired catalyst precursor. The catalyst precursor was calcined at 450 °C in air for 12 h to obtain the catalyst.

[0085] During the microreactor evaluation, the catalyst loading was 3 g, the reaction temperature was 400 °C, the pressure was 0.1 MPa (absolute pressure), the acetic acid / methanol feed molar ratio was 0.4 / 1, and the mass hourly space velocity (HHSV) was 0.6 h⁻¹. -1 The air flow rate was 50 mL / min. Catalyst evaluation results showed that the acetic acid conversion rate was 52.2 wt%, and the selectivity for acrylic acid and methyl acrylate was 50.2 wt%.

[0086] Example 3:

[0087] 7.5 g of V₂O₅ was added to a mixture of isobutanol / benzyl alcohol (60 mL: 30 mL), and the mixture was stirred and refluxed at 100 °C for 6 h. After cooling to 80 °C, 4.2 g of barium acetate and 11.4 g of phosphoric acid (85 wt%) were added, and the mixture was stirred and refluxed for 15 h to obtain a suspension. The resulting suspension was filtered and then dried at 120 °C to obtain the desired catalyst precursor. The catalyst precursor was calcined at 520 °C in air for 9 h to obtain the catalyst.

[0088] During the microreactor evaluation, the catalyst loading was 3 g, the reaction temperature was 420 °C, the pressure was 0.1 MPa (absolute pressure), the methyl acetate / methanol feed molar ratio was 0.3 / 1, and the mass hourly space velocity (HHSV) was 1.0 h⁻¹. -1 The air flow rate was 80 mL / min. Catalyst evaluation results showed that the methyl acetate conversion rate was 82.2 wt%, and the selectivity for acrylic acid and methyl acrylate was 38.4 wt%.

[0089] Example 4:

[0090] 7.5 g of V₂O₅ was added to a mixture of isobutanol / benzyl alcohol (50 mL: 30 mL), and the mixture was stirred and refluxed at 110 °C for 6 h. After cooling to 70 °C, 9.7 g of calcium nitrate and 11.4 g of phosphoric acid (85 wt%) were added, and the mixture was stirred and refluxed for 16 h to obtain a suspension. The resulting suspension was filtered and then dried at 110 °C to obtain the desired catalyst precursor. The catalyst precursor was calcined in air at 500 °C for 10 h to obtain the catalyst.

[0091] During the microreactor evaluation, the catalyst loading was 3g, the reaction temperature was 380℃, the pressure was 0.1MPa (absolute pressure), the acetic acid / methanol feed molar ratio was 0.3 / 1, and the mass hourly space velocity (HHSV) was 0.8h. -1 The air flow rate was 60 mL / min. Catalyst evaluation results showed that the acetic acid conversion rate was 42.5 wt%, and the selectivity for acrylic acid and methyl acrylate was 40.3 wt%.

[0092] Example 5:

[0093] 7.5 g of V₂O₅ was added to a mixture of isobutanol / benzyl alcohol (50 mL: 20 mL), and the mixture was stirred and refluxed at 100 °C for 8 h. After cooling to 80 °C, 22.6 g of cerium ammonium nitrate and 9.5 g of phosphoric acid (85 wt%) were added, and the mixture was stirred and refluxed for 20 h to obtain a suspension. The resulting suspension was filtered and then dried at 90 °C to obtain the desired catalyst precursor. The catalyst precursor was calcined at 480 °C in air for 10 h to obtain the catalyst.

[0094] During the microreactor evaluation, the catalyst loading was 3g, the reaction temperature was 400℃, the pressure was 0.1MPa (absolute pressure), the methyl acetate / methanol feed molar ratio was 0.5 / 1, and the mass hourly space velocity (HHSV) was 0.8h. -1 The air flow rate was 55 mL / min. Catalyst evaluation results showed that the methyl acetate conversion was 52.6 wt%, and the selectivity for acrylic acid and methyl acrylate was 39.9 wt%.

[0095] Example 6:

[0096] 7.5 g of V₂O₅ was added to a mixture of isobutanol / benzyl alcohol (60 mL:30 mL), and the mixture was stirred and refluxed at 100 °C for 6 h. After cooling to 70 °C, 7.1 g of lanthanum nitrate and 9.5 g of phosphoric acid (85 wt%) were added, and the mixture was stirred and refluxed for 18 h to obtain a suspension. The resulting suspension was filtered and then dried at 110 °C to obtain the desired catalyst precursor. The catalyst precursor was calcined in air at 520 °C for 10 h to obtain the catalyst.

[0097] During the microreactor evaluation, the catalyst loading was 3g, the reaction temperature was 380℃, the pressure was 0.1MPa (absolute pressure), the acetic acid / methanol feed molar ratio was 0.4 / 1, and the mass hourly space velocity (HHSV) was 0.5h. -1 The air flow rate was 40 mL / min. Catalyst evaluation results showed that the acetic acid conversion rate was 54.2 wt%, and the selectivity for acrylic acid and methyl acrylate was 43.6 wt%.

[0098] Example 7:

[0099] 7.5 g of V₂O₅ was added to a mixture of isobutanol / benzyl alcohol (50 mL: 25 mL), and the mixture was stirred and refluxed at 120 °C for 6 h. After cooling to 90 °C, 24.5 g of ammonium metatungstate and 14.3 g of phosphoric acid (85 wt%) were added, and the mixture was stirred and refluxed for 16 h to obtain a suspension. The resulting suspension was filtered and then dried at 110 °C to obtain the desired catalyst precursor. The catalyst precursor was calcined in air at 500 °C for 10 h to obtain the catalyst.

[0100] During the microreactor evaluation, the catalyst loading was 3 g, the reaction temperature was 410 °C, the pressure was 0.1 MPa (absolute pressure), the acetic acid / methanol feed molar ratio was 0.5 / 1, and the mass hourly space velocity (HHSV) was 0.8 h⁻¹. -1 The air flow rate was 50 mL / min. Catalyst evaluation results showed that the acetic acid conversion rate was 55.5 wt%, and the selectivity for acrylic acid and methyl acrylate was 39.7 wt%.

[0101] Example 8:

[0102] 7.5 g of V₂O₅ was added to a mixture of isobutanol / benzyl alcohol (50 mL: 25 mL), and the mixture was stirred and refluxed at 100 °C for 6 h. After cooling to 65 °C, 15.8 g of cesium acetate and 14.3 g of phosphoric acid (85 wt%) were added, and the mixture was stirred and refluxed for 10 h to obtain a suspension. The resulting suspension was filtered and then dried at 80 °C to obtain the desired catalyst precursor. The catalyst precursor was calcined in air at 500 °C for 14 h to obtain the catalyst.

[0103] During the microreactor evaluation, the catalyst loading was 3g, the reaction temperature was 380℃, the pressure was 0.1MPa (absolute pressure), the acetic acid / methanol feed molar ratio was 0.3 / 1, and the mass hourly space velocity (HHSV) was 0.8h. -1 The air flow rate was 60 mL / min. Catalyst evaluation results showed that the acetic acid conversion rate was 46.9 wt%, and the selectivity for acrylic acid and methyl acrylate was 38.3 wt%.

[0104] Example 9:

[0105] 7.5 g of V₂O₅ was added to a mixture of isobutanol / benzyl alcohol (50 mL: 30 mL), and the mixture was stirred and refluxed at 110 °C for 10 h. After cooling to 70 °C, 3.1 g of titanium tetrachloride, 1.4 g of cesium acetate, and 11.4 g of phosphoric acid (85 wt%) were added, and the mixture was stirred and refluxed for 16 h to obtain a suspension. The resulting suspension was filtered and then dried at 90 °C to obtain the desired catalyst precursor. The catalyst precursor was calcined in air at 500 °C for 12 h to obtain the catalyst.

[0106] During the microreactor evaluation, the catalyst loading was 3g, the reaction temperature was 400℃, the pressure was 0.1MPa (absolute pressure), the acetic acid / methanol feed molar ratio was 0.5 / 1, and the mass hourly space velocity (HHSV) was 0.5h⁻¹. -1 The air flow rate was 70 mL / min. Catalyst evaluation results showed that the acetic acid conversion rate was 60.7 wt%, and the selectivity for acrylic acid and methyl acrylate was 47.8 wt%.

[0107] Example 10:

[0108] 7.5 g of V₂O₅ was added to a mixture of isobutanol / benzyl alcohol (50 mL: 25 mL), and the mixture was stirred and refluxed at 110 °C for 6 h. After cooling to 90 °C, 10.2 g of ammonium molybdate, 1.7 g of barium acetate, and 9.5 g of phosphoric acid (85 wt%) were added, and the mixture was stirred and refluxed for 18 h to obtain a suspension. The resulting suspension was filtered and then dried at 110 °C to obtain the desired catalyst precursor. The catalyst precursor was calcined at 500 °C in air for 10 h to obtain the catalyst.

[0109] During the microreactor evaluation, the catalyst loading was 3 g, the reaction temperature was 390 °C, the pressure was 0.1 MPa (absolute pressure), the acetic acid / methanol feed molar ratio was 0.4 / 1, and the mass hourly space velocity (HHSV) was 1.0 h⁻¹. -1 The air flow rate was 60 mL / min. Catalyst evaluation results showed that the acetic acid conversion rate was 51.4 wt%, and the selectivity for acrylic acid and methyl acrylate was 50.1 wt%.

[0110] Comparative Example 1

[0111] 7.5 g of V₂O₅ was added to a mixture of isobutanol / benzyl alcohol (50 mL: 25 mL), and the mixture was stirred and refluxed at 110 °C for 6 h. After cooling to 70 °C, 32.7 g of silica was added, and the mixture was stirred for 0.5 h. Then, 4.9 g of zinc nitrate and 9.5 g of phosphoric acid (85 wt%) were added, and the mixture was stirred and refluxed for 16 h to obtain a suspension. The resulting suspension was filtered and then dried at 110 °C to obtain the desired catalyst precursor. The catalyst precursor was calcined in air at 500 °C for 10 h to obtain the catalyst.

[0112] During the microreactor evaluation, the catalyst loading was 3g, the reaction temperature was 380℃, the pressure was 0.1MPa (absolute pressure), the acetic acid / methanol feed molar ratio was 0.5 / 1, and the mass hourly space velocity (HHSV) was 0.8h. -1 The air flow rate was 60 mL / min. Catalyst evaluation results showed that the acetic acid conversion rate was 37.5 wt%, and the selectivity for acrylic acid and methyl acrylate was 25.5 wt%.

[0113] Comparative Example 2

[0114] 7.5 g of V₂O₅ was added to a mixture of isobutanol / benzyl alcohol (40 mL:40 mL), and the mixture was stirred and refluxed at 120 °C for 8 h. After cooling to 60 °C, 56.0 g of silica was added, and the mixture was stirred for 0.5 h. Then, 10.2 g of ammonium molybdate and 7.6 g of phosphoric acid (85 wt%) were added, and the mixture was stirred and refluxed for 18 h to obtain a suspension. The resulting suspension was filtered and then dried at 100 °C to obtain the desired catalyst precursor. The catalyst precursor was calcined at 450 °C in air for 12 h to obtain the catalyst.

[0115] During the microreactor evaluation, the catalyst loading was 3 g, the reaction temperature was 400 °C, the pressure was 0.1 MPa (absolute pressure), the acetic acid / methanol feed molar ratio was 0.4 / 1, and the mass hourly space velocity (HHSV) was 0.6 h⁻¹. -1 The air flow rate was 50 mL / min. Catalyst evaluation results showed that the acetic acid conversion rate was 36.0 wt%, and the selectivity for acrylic acid and methyl acrylate was 20.2 wt%.

[0116] Comparative Example 3

[0117] 7.5 g of V₂O₅ was added to a water / oxalic acid (60 mL:30 mL) mixture, and the mixture was stirred and refluxed at 100 °C for 6 h. After cooling to 70 °C, 7.1 g of lanthanum nitrate and 9.5 g of phosphoric acid (85 wt%) were added, and the mixture was stirred and refluxed for 18 h to obtain a suspension. The resulting suspension was filtered and then dried at 110 °C to obtain the desired catalyst precursor. The catalyst precursor was calcined in air at 520 °C for 10 h to obtain the catalyst.

[0118] During the microreactor evaluation, the catalyst loading was 3g, the reaction temperature was 380℃, the pressure was 0.1MPa (absolute pressure), the acetic acid / methanol feed molar ratio was 0.4 / 1, and the mass hourly space velocity (HHSV) was 0.5h. -1 The air flow rate was 40 mL / min. Catalyst evaluation results showed that the acetic acid conversion rate was 46.8 wt%, and the selectivity for acrylic acid and methyl acrylate was 37.7 wt%.

[0119] Comparative Example 4

[0120] 7.5 g of V₂O₅ was added to a mixture of isobutanol / benzyl alcohol (50 mL: 25 mL), and the mixture was stirred and refluxed at 110 °C for 10 h. After cooling to 70 °C, 11.4 g of phosphoric acid (85 wt%) was added, and the mixture was stirred and refluxed for 16 h to obtain a suspension. The resulting suspension was filtered and then dried at 100 °C to obtain the desired catalyst precursor. The catalyst precursor was calcined in air at 500 °C for 12 h to obtain the catalyst.

[0121] During the microreactor evaluation, the catalyst loading was 3g, the reaction temperature was 400℃, the pressure was 0.1MPa (absolute pressure), the acetic acid / methanol feed molar ratio was 0.5 / 1, and the mass hourly space velocity (HHSV) was 0.5h⁻¹. -1 The air flow rate was 70 mL / min. Catalyst evaluation results showed that the acetic acid conversion rate was 40.1 wt%, and the selectivity for acrylic acid and methyl acrylate was 26.1 wt%.

[0122] Experimental Example 1

[0123] This experimental example demonstrates the stability of the catalysts prepared in Examples 1-2, 7 and Comparative Examples 1-3 in the one-step preparation of acrylic acid.

[0124] The reaction conditions were the same as those in Example 7 for microreactor evaluation. The reaction was carried out continuously for 100 hours, and samples were taken and the products were analyzed every 5 hours. The results are shown in Table 1.

[0125] Table 1

[0126]

Claims

1. A catalyst for one-step preparation of acrylic acid / acrylate, comprising vanadium, phosphorus, oxygen and a second metal; the second metal comprises metal element M1 and / or metal element M2, the metal element M1 comprises one or more than two metal elements selected from the group consisting of Pt, Pd, Ru, Rh, Ti, W, Zr, Ce, La, Zn, Mo, Nb, and the metal element M2 comprises one or more than two metal elements selected from the group consisting of Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba.

2. The catalyst according to claim 1, characterized in that, The second metal comprises the metal element M1 or the metal element M2; The metal element M1 is selected from one or more than two metal elements selected from the group consisting of Pt, Pd, Ru, Rh, W, Zr, Ce, La, Zn, Mo, Nb; The metal element M2 is selected from one or more than two metal elements selected from the group consisting of Na, K, Cs, Mg, Ca, Ba; Preferably, the metal element M1 is selected from one or more than two metal elements selected from the group consisting of W, Ce, La, Zn, Mo; The metal element M2 is selected from one or more than two metal elements selected from the group consisting of Na, K, Cs, Ca, Ba; More preferably, the metal element M1 is selected from one or two metal elements selected from the group consisting of La, Zn, Mo.

3. The catalyst of claim 1, wherein The second metal comprises the metal element M1 and the metal element M2; The metal element M1 is selected from one or more than two metal elements selected from the group consisting of Ti, W, Ce, La, Zn, Mo, and the metal element M2 is selected from one or more than two metal elements selected from the group consisting of Na, K, Ba, Cs.

4. Catalyst according to any one of claims 1 to 3, characterized in that The molar ratio of the phosphorus element, the vanadium element and the metal M1 is (0.5-2):1:(0.01-10), The molar ratio of the phosphorus element, the vanadium element and the metal M2 is (0.5-2):1:(0.01-10); Preferably, the molar ratio of the phosphorus element, the vanadium element and the metal M1 is (0.8-1.6) / 1 / (0.1-1), The molar ratio of the phosphorus element, the vanadium element and the metal M2 is (0.8-1.6) / 1 / (0.1-1).

5. A process for the preparation of the catalyst of any one of claims 1 to 4 comprising: 1) V2O5 is mixed in a mixture of fatty alcohol / phenylmethanol at a temperature of 90-150℃; 2) after the mixture obtained in step 1) is cooled, a precursor of the metal element M1 and / or the metal element M2, and phosphoric acid are added, and after sufficient mixing, a suspension is obtained; 3) the suspension obtained in step 2) is subjected to suction filtration, washing, drying and calcination to obtain the catalyst; Preferably, the fatty alcohol comprises isobutyl alcohol or n-butyl alcohol, and the volume ratio of isobutyl alcohol or n-butyl alcohol to phenylmethanol is 1:1-4:1; Preferably, in step 3), the drying temperature is 80-140℃, The dried catalyst precursor is calcined in an air atmosphere at 350-650℃ to obtain the catalyst; More preferably, the calcination temperature is controlled at 420-550℃.

6. The production method according to claim 5, characterized by, V2O5 is mixed in a mixture of isobutyl alcohol / phenylmethanol in the above-mentioned ratio under reflux at a temperature of 90-150℃; Preferably, the reflux time is 2-10h.

7. The production method according to claim 5 or 6, characterized by, In step 2), the mixture of step 1), the precursor of the metal element M1 and / or the metal element M2, and the phosphoric acid are mixed at a temperature of 50-80℃; Preferably, the several substances of step 2) are mixed and stirred under reflux for 8-20 hours.

8. A process for the one-step production of acrylic acid / acrylates comprising: The reaction is carried out at a temperature of 300-450℃ in the presence of the catalyst of any one of claims 1-4, using methanol and acetic acid as raw materials, or methanol and acetic acid ester as raw materials, or methanol, acetic acid and acetic acid ester as raw materials, to obtain acrylic acid and acetic acid ester; Preferably, the reaction temperature is 350-450℃; Preferably, the absolute pressure during the reaction is 0.01-0.5 MPa; More preferably, the absolute pressure during the reaction is 0.05-0.2 MPa.

9. The method of claim 8, wherein, The molar ratio of acetic acid to methanol is (0.1-2) : 1; preferably, the molar ratio of acetic acid to methanol is (0.2-1) : 1; The molar ratio of acetic acid ester to methanol is (0.1-2) : 1; preferably, the molar ratio of acetic acid ester to methanol is (0.2-1) : 1; More preferably, the raw materials are gasified outside the reactor and the mass space velocity of the mixed gas is 0.1-2.5h -1 ; preferably, the mass space velocity is 0.2-1.0h -1 .

10. The method according to claim 8 or 9, characterized in that, During the reaction of methanol and acetic acid, or methanol and acetic acid ester, an oxygen-containing gas is continuously fed in; The flow rate of the oxygen-containing gas is 2-100 mL / min / g cat; Preferably, the flow rate of the oxygen-containing gas is 5-50 mL / min / g cat; Preferably, the acetic acid ester includes one or more than two kinds of mixture of methyl acetate, ethyl acetate, propyl acetate, and butyl acetate.

Images