Method for preparing alpha, beta-unsaturated carbonyl compound

Abstract

The invention relates to a method for preparing an alpha, beta-unsaturated carbonyl compound, which adopts a molecular sieve with skeleton metal elements and non-skeleton metal elements as a catalyst, and the skeleton metal elements and the non-skeleton metal elements have a synergistic effect when an aldol condensation reaction is catalyzed, so that the aldol condensation reaction efficiency can be improved, and the alpha, beta-unsaturated carbonyl compound is prepared. And the method has relatively high raw material conversion rate and product selectivity so as to obtain the high-purity alpha, beta-unsaturated carbonyl compound. Compared with the prior art, the method disclosed by the invention is simple to operate and relatively high in raw material conversion rate and product selectivity, and has a good industrial application prospect.

Description

Technical Field

[0001] The present disclosure relates to an aldol condensation reaction, and in particular, to a method for preparing an α,β-unsaturated carbonyl compound. Background Art

[0002] Methyl methacrylate (MMA) is an important organic chemical raw material, mainly used to produce polymethyl methacrylate) and acrylic resin materials. It is also widely used in the manufacture of other resins, plastics, coatings, adhesives, lubricants, wetting agents, glazing agents, printing and dyeing auxiliaries and insulating filling materials.

[0003] It is known that the most effective methyl propionate and formaldehyde aldol condensation catalyst is a kind of silica as the main carrier, cesium as the main active component of the supported catalyst, researchers have carried out a large number of studies and modifications on the catalyst, CN112675830A modifies the carrier silica to extend the life of the catalyst, with foam porous silica as the carrier, loading cesium metal element. The catalyst is made to have excellent water resistance, anti-carbon deposition performance and long-term activity stability, and is suitable for the industrial application of methyl propionate and formaldehyde to prepare methyl methacrylate through aldol condensation. Although the life of the catalyst is improved, there is still a problem of low conversion rate of methyl propionate. CN103551148B improves selectivity by adding an active additive, and the main active ingredient includes one or more of the oxide or salt of Cs, and the active additive is one or more of the oxide or salt of Sb, Nb, Ag, Al, and Zr, and the carrier includes SiO2 and a carrier additive. Although the product selectivity is improved, the conversion rate of methyl propionate is also low.

[0004] In order to improve the performance of the catalyst, researchers have developed other catalysts. Wierzchowsky and Zatorski, Catalysis Letters 9 (1991), pages 411 to 414 recorded the aldol condensation of formaldehyde and methyl propionate prepared in situ in the gas phase by various zeolite catalysts, the conversion of methyl propionate was less than 20%, and the selectivity of methyl methacrylate was as high as 74.1%. Mamoru Ai reported in Bull.Chem.Soc.Jpn., 63, 3722-3724 (1990) that V-Si-P ternary oxide was used as a catalyst in the reaction of methyl propionate and formaldehyde aldol condensation to prepare methyl methacrylate. The molar ratio of the reaction raw materials methyl propionate, formaldehyde, and methanol was 1:1:1, the reaction temperature was 320°C, the atomic ratio of V-Si-P ternary oxide was 1:16:3.2, the conversion of methyl propionate was about 35%, and the total yield of methyl methacrylate and methacrylic acid was 53 mol%.

[0005] Although many methods for preparing methyl methacrylate have been developed, due to the low catalytic activity of the catalyst, there is still a need to develop an improved method for preparing methyl methacrylate from a formaldehyde source and methyl propionate as raw materials. Summary of the invention

[0006] The purpose of the present disclosure is to provide a method for producing an α,β-unsaturated carbonyl compound, which uses a molecular sieve having a framework metal element and a non-framework metal element as a catalyst and can catalyze an aldol condensation reaction of a carbonyl compound raw material to produce an α,β-unsaturated carbonyl compound.

[0007] In order to achieve the above-mentioned object, the present disclosure provides a method for preparing an α,β-unsaturated carbonyl compound, the method comprising: contacting a carbonyl compound raw material and a catalyst and performing an aldol condensation reaction, the carbonyl compound raw material comprising one or more of aldehydes, ketones and esters, the catalyst comprising a molecular sieve having a metal element, the metal element being selected from one or more of Ti, Zr, Hf, Sn and Pb; the metal element comprising a skeleton metal element and a non-skeleton metal element, based on the total molar number of all metal elements in the molecular sieve, the content of the skeleton metal element is 10 to 80 mol%, and the content of the non-skeleton metal element is 20 to 90 mol%; the molar ratio of the non-skeleton metal element to the skeleton metal element is (0.25 to 9):1, wherein the content of the metal element is calculated as metal oxide.

[0008] Optionally, the total acid content of B acid of the catalyst measured by pyridine adsorption infrared method at 50°C is 50 μmol·g -1 Below, preferably 5 μmol·g -1 Below, more preferably 0 μmol·g -1 ; L acid total acid content is 50~1000μmol·g -1 , preferably 300 to 800 μmol·g -1 .

[0009] Optionally, based on the total molar number of all metal elements in the molecular sieve, the content of the framework metal element is 10-50 mol%, preferably 10-30 mol%; the content of the non-framework metal element is 50-90 mol%, preferably 50-80 mol%; the molar ratio of the non-framework metal element to the framework metal element is (1-7):1, preferably (2-5):1, and more preferably (3-4):1; the molar ratio of the framework metal element to the silicon element in the molecular sieve is (0.005-0.5):1, preferably (0.02-0.2):1, and more preferably (0.02-0.15):1, wherein the content of the silicon element is calculated as SiO2.

[0010] Optionally, the molecular sieve is one or more selected from MFI type molecular sieve, MEL type molecular sieve, BEA type molecular sieve, MWW type molecular sieve, FAU type molecular sieve and MOR type molecular sieve, preferably one or more selected from MFI type molecular sieve, MEL type molecular sieve and BEA type molecular sieve.

[0011] Optionally, the carbonyl compound raw material includes a first carbonyl compound and a second carbonyl compound, wherein the first carbonyl compound has a structure as shown in the following formula (1), and the second carbonyl compound has a cyclic ketone, a structure as shown in the following formula (1), formula (2) or formula (3):

[0012]

[0013] Wherein, the R1-R2 are each independently selected from one or more of hydrogen, a halogen group, an alkyl group with 1 to 12 carbon atoms, a substituted or unsubstituted cycloalkyl group with 3 to 12 carbon atoms, a substituted or unsubstituted aryl group with 6 to 14 carbon atoms, and an alkoxy group with 1 to 12 carbon atoms; the R4-R6 are each independently selected from one or more of a halogen group, an alkyl group with 1 to 12 carbon atoms, a substituted or unsubstituted cycloalkyl group with 3 to 12 carbon atoms, a substituted or unsubstituted aryl group with 6 to 14 carbon atoms, and an alkoxy group with 1 to 12 carbon atoms; the R3, R7-R8 are each independently selected from one or more of hydrogen, an alkyl group with 1 to 12 carbon atoms, an alkoxy group with 1 to 12 carbon atoms, and a substituted or unsubstituted furyl group with 4 to 20 carbon atoms; the cyclic ketone is selected from a substituted or unsubstituted cyclic ketone with 4 to 8 carbon atoms.

[0014] Optionally, the halogen group is selected from one or more of fluorine, chlorine, bromine and iodine, preferably chlorine; the alkyl group having 1 to 12 carbon atoms is selected from one or more of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl, neopentyl, 1,2-dimethylpropyl, isopentyl, n-hexyl, isohexyl, sec-hexyl, n-heptyl, isoheptyl, n-octyl, n-nonyl, n-decyl and n-dodecyl, preferably methyl; the unsubstituted cycloalkyl group is selected from cyclopropyl, One or more of cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, cycloundecyl and cyclododecyl; wherein the substituent on the substituted cycloalkyl is selected from an alkyl group having 1 to 9 carbon atoms, preferably one or more of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl and tert-butyl; more preferably, the substituted or unsubstituted cycloalkyl group having 3 to 12 carbon atoms is selected from one or more of cyclopentyl, cyclohexyl and cycloheptyl; the unsubstituted aryl group is selected from phenyl , naphthyl, anthracenyl and phenanthryl, wherein the substituent on the substituted aryl is selected from an alkyl group having 1 to 8 carbon atoms, preferably one or more of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl and tert-butyl; more preferably, the substituted or unsubstituted aryl group having 6 to 14 carbon atoms is selected from one or more of phenyl, benzyl, propylphenyl and butylphenyl, further preferably phenyl; the alkoxy group having 1 to 12 carbon atoms is selected from methoxy, ethoxy, n-propyloxy, isopropyl, n-butyl, isobutyl, sec-butyl and tert-butyl. One or more of propoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, n-pentyloxy, isopentylpropoxy, n-hexyloxy and isohexyloxy, preferably one or more of methoxy, ethoxy, n-propoxy and n-butoxy; the substituent on the substituted furanyl is selected from one or more of methyl, ethyl and hydroxymethyl; the unsubstituted cyclic ketone is selected from one or more of cyclopentanone, cyclohexanone and octacyclic ketone, wherein the substituent on the substituted cyclic ketone is selected from one or more of methyl, ethyl, n-propyl and isopropyl.

[0015] Optionally, the first carbonyl compound is selected from one or more of acetaldehyde, propionaldehyde, acetone, butanone, hexanone, methyl acetate, ethyl acetate, methyl propionate and methyl butyrate, preferably methyl propionate; the second carbonyl compound is selected from one or more of cyclohexanone, cyclopentanone, methyl acetate, ethyl acetate, methyl propionate, methyl butyrate, 2,2-dimethylpropionate, 2,2-dimethylpropionaldehyde, formaldehyde, benzaldehyde, furfural, 5-hydroxyfurfural and 5-methylfurfural, preferably formaldehyde.

[0016] Optionally, the molar ratio of the first carbonyl compound to the second carbonyl compound is (0.5-10):1, preferably (0.5-8):1, and more preferably (0.5-5):1.

[0017] Optionally, the reaction conditions also include: contacting a carbonyl compound raw material, a diluent and a catalyst and conducting an aldol condensation reaction, wherein the diluent is selected from one or more of alcohols, ethers, alkanes and aromatic hydrocarbons, preferably one or more of alcohols with carbon atoms of 1 to 12, ethers with carbon atoms of 1 to 12, alkanes with carbon atoms of 6 to 12 and aromatic hydrocarbons with carbon atoms of 6 to 20, more preferably one or more of methanol, ether, cyclohexane and toluene; the molar ratio of the diluent to the carbonyl compound raw material is (0.5 to 10):1, preferably (0.5 to 5):1, and more preferably (1 to 3):1.

[0018] Optionally, the reaction temperature is 200-500°C, preferably 250-480°C, more preferably 300-400°C; the reaction time is 0.2-24h, preferably 0.5-12h; the pressure is 0.01-2.4MPa, preferably 0.5-1MPa; the reaction is carried out in a reactor, and the reactor includes a fixed bed reactor, a fluidized bed reactor or a tank reactor; the reactor is a fixed bed reactor, and the mass liquid hourly space velocity of the reaction is 0.1-5h based on the total volume of the carbonyl compound raw material and the diluent. -1 , preferably 0.1 to 2 hours -1 , more preferably 0.1 to 1 h -1 ; The reactor is a fluidized bed reactor, and the weight ratio of the carbonyl compound raw material to the catalyst is (10-500):1, preferably (20-200):1; the reactor is a kettle reactor, and the weight ratio of the carbonyl compound raw material to the catalyst is (1-200):1, preferably (2-50):1.

[0019] Optionally, the reaction is carried out in an inert atmosphere or an oxygen-containing compound atmosphere, wherein the inert atmosphere includes one or more of nitrogen, helium and argon, and the oxygen-containing compound atmosphere includes carbon monoxide and / or carbon dioxide.

[0020] Through the above technical scheme, the present disclosure uses a molecular sieve with skeleton metal elements and non-skeleton metal elements as a catalyst, wherein the skeleton metal elements and the non-skeleton metal elements are not easy to be lost, and can synergistically catalyze the aldol condensation reaction of the carbonyl compound raw material to obtain a high-purity α, β-unsaturated carbonyl compound. Compared with the prior art, the method disclosed in the present disclosure is simple to operate, has a high raw material conversion rate and product selectivity, and has good industrial application prospects.

[0021] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0023] Figure 1 is the UV-visible spectrum of the catalyst 1 prepared in Preparation Example 1 of the present disclosure;

[0024] Figure 2 is the pyridine acid infrared spectrum of catalyst 1 prepared in Preparation Example 1 of the present disclosure;

[0025] Figure 3 It is the UV-visible spectrum of comparative catalyst 4 prepared in comparative example 4 of the present disclosure. DETAILED DESCRIPTION

[0026] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0027] The present disclosure provides a method for preparing an α,β-unsaturated carbonyl compound. The method comprises: contacting a carbonyl compound raw material and a catalyst and performing an aldol condensation reaction, wherein the carbonyl compound raw material comprises one or more of aldehydes, ketones and esters, and the catalyst comprises a molecular sieve having a metal element, wherein the metal element is selected from one or more of Ti, Zr, Hf, Sn and Pb; the metal element comprises a skeleton metal element and a non-skeleton metal element, and based on the total molar number of all metal elements in the molecular sieve, the content of the skeleton metal element is 10 to 80 mol %, and the content of the non-skeleton metal element is 20 to 90 mol %; the molar ratio of the non-skeleton metal element to the skeleton metal element is (0.25 to 9):1, wherein the content of the metal element is calculated as metal oxide.

[0028] In the present disclosure, when the metal element is Ti, its element content is calculated as TiO2; when the metal element is Zr, its element content is calculated as ZrO2; when the metal element is Hf, its element content is calculated as HfO2; when the metal element is Sn, its element content is calculated as SnO2; when the metal element is Pb, its element content is calculated as PbO; the skeleton metal element of the present disclosure refers to the metal element located in the molecular sieve lattice framework and replacing a part of the silicon atoms in the molecular sieve lattice framework, and the non-skeleton metal element refers to the metal element located outside the molecular sieve framework and in the form of metal oxide. The content of the metal element in the molecular sieve of the present disclosure can be determined by the conventional XRF method in the art, and the distinction between the skeleton metal element and the non-skeleton metal element in the molecular sieve can be determined by ultraviolet visible spectroscopy (UV-Vis). For example, when using UV-visible spectroscopy to analyze molecular sieves with Ti as the metal element, it is generally believed that the absorption peak appearing near a wavelength of 210 nm is the characteristic peak of the framework tetracoordinated titanium species (Stanislaw, Dzwigaj, Yannick, et al. [J]. The Journal of Physical Chemistry C, 2013, 117 (24): 12552-12559.); the absorption peak appearing near a wavelength of 270 nm is the "TiO6" species, "TiO6" is in a hydrated state, one or two water moles or hydroxyl groups will form a stable complex with the framework tetracoordinated Ti position, and their oxygen coordination will be extended from the 4th position to the 5th position or the 6th position. We also define this form of titanium species as framework titanium (Q Guo, K Sun, Z Feng, et al. A Thorough Investigation of the Active Titanium Species in TS-1 Zeolite by In Situ UV Resonance Raman Spectroscopy [J]. Chem. Eur. J. 2012). The absorption peak appearing near a wavelength of 330 nm is a characteristic peak of a non-framework octahedral metal oxide, namely anatase-type titanium species (Xiong G, Cao Y, Guo Z, et al. Physical Chemistry Chemical Physics, 2015, 18(1): 190-196).

[0029] The inventors of the present disclosure have found in their research that when a molecular sieve having skeleton metal elements and non-skeleton metal elements is used as a catalyst to catalyze the aldol condensation reaction, the skeleton metal elements and the non-skeleton metal elements have a synergistic effect, wherein the skeleton metal elements provide Lewis acid sites, which are conducive to the adsorption of carbonyl compound raw materials and promote the proton transfer of carbonyl compound raw materials, reduce the active free energy of carbonyl compound raw materials, and improve their conversion rate; while the non-skeleton metal elements can provide Lewis acid-base pairs, which can adsorb carbonyl compound raw materials and are conducive to the enolization of carbonyl compound raw materials to form enol ester intermediates, which can couple with adjacent carbonyl compound raw materials, thereby improving the activity of the aldol condensation reaction and improving the product selectivity, so as to obtain high-purity α, β-unsaturated carbonyl compounds. Compared with the prior art, the method disclosed in the present disclosure is simple to operate, has high raw material conversion rate and product selectivity, and has good industrial application prospects.

[0030] In one embodiment of the present disclosure, the total acid content of B acid measured by pyridine adsorption infrared method at 50°C is 50 μmol·g -1 Below, preferably 5 μmol·g -1 Below, more preferably 0 μmol·g -1 ; L acid total acid content is 50~1000μmol·g -1 , preferably 300 to 800 μmol·g -1 , more preferably 350 to 650 μmol·g -1 , more preferably 400 to 500 μmol·g -1 In the above embodiment, the catalytic activity of the catalyst can be further improved by selecting a preferred acid strength. The pyridine adsorption infrared spectrum is 1540cm -1 The peak at 1446±5cm -1 The peak at reflects the L acid characteristics of the molecular sieve. The B acid characteristics are provided by other impurity metal elements of the molecular sieve, such as metal aluminum, and the L acid characteristics are mainly provided by the skeleton metal elements.

[0031] In one embodiment of the present disclosure, based on the total molar number of all metal elements in the molecular sieve, the content of the skeleton metal element is 10-50 mol%, preferably 10-30 mol%; the content of the non-skeleton metal element is 50-90 mol%, preferably 50-80 mol%; the molar ratio of the non-skeleton metal element to the skeleton metal element is (1-7):1, preferably (2-5):1, and more preferably (3-4):1; the molar ratio of the skeleton metal element to the silicon element in the molecular sieve is (0.005-0.5):1, preferably (0.02-0.2):1, and more preferably (0.02-0.15):1, wherein the content of the silicon element is calculated as SiO2, and the silicon element includes all silicon in the molecular sieve. In the above embodiment, by selecting the preferred content of the skeleton metal element and the non-skeleton metal element, the synergistic effect between the two can be further improved, and the catalytic activity of the catalyst can be improved.

[0032] In a preferred embodiment, when the metal element is Ti and / or Zr, the molar ratio of the non-framework metal element to the framework metal element can be (2-5):1, preferably (3-4):1, and more preferably (3.1-3.5):1; when the metal element is one or more of Hf, Sn and Pb, the molar ratio of the non-framework metal element to the framework metal element can be (5-7):1, preferably (6-7):1, and more preferably (6.1-6.5):1.

[0033] In one embodiment of the present disclosure, the molecular sieve is a product of metal elements replacing part of the framework silicon of molecular sieves of various topological structures. The topological structure of the molecular sieve can be referenced from the website of the International Zeolite Association. For example, the molecular sieve can be selected from one or more of MFI type molecular sieves, MEL type molecular sieves, BEA type molecular sieves, MWW type molecular sieves, FAU type molecular sieves and MOR type molecular sieves, preferably one or more of MFI type molecular sieves, MEL type molecular sieves and BEA type molecular sieves.

[0034] In one embodiment, when the skeleton metal element and the non-skeleton metal element are both Ti, the molecular sieve is a titanium silicon molecular sieve, and the titanium silicon molecular sieve is selected from one or more of MFI type titanium silicon molecular sieve, MEL type titanium silicon molecular sieve, BEA type titanium silicon molecular sieve, MWW type titanium silicon molecular sieve, FAU type titanium silicon molecular sieve and MOR type titanium silicon molecular sieve, MFI type titanium silicon molecular sieve is, for example, Ti-MFI molecular sieve, MEL type titanium silicon molecular sieve is, for example, Ti-MEL molecular sieve, BEA type titanium silicon molecular sieve is, for example, Ti-Beta molecular sieve, MWW type titanium silicon molecular sieve is, for example, Ti-MCM-22 molecular sieve, FAU type titanium silicon molecular sieve is, for example, Ti-FAU molecular sieve, MOR type titanium silicon molecular sieve is, for example, Ti-MOR molecular sieve. Further preferably, the titanium silicon molecular sieve is an MFI type titanium silicon molecular sieve.

[0035] In another embodiment, when the skeleton metal element and the non-skeleton metal element are both Sn, the molecular sieve is a tin silicon molecular sieve, and the tin silicon molecular sieve is selected from one or more of MFI type tin silicon molecular sieve, MEL type tin silicon molecular sieve, BEA type tin silicon molecular sieve, MWW type tin silicon molecular sieve, FAU type tin silicon molecular sieve and MOR type tin silicon molecular sieve, MFI type tin silicon molecular sieve is, for example, Sn-MFI molecular sieve, MEL type tin silicon molecular sieve is, for example, Sn-MEL molecular sieve, BEA type tin silicon molecular sieve is, for example, Sn-Beta molecular sieve, MWW type tin silicon molecular sieve is, for example, Sn-MCM-22 molecular sieve, FAU type tin silicon molecular sieve is, for example, Sn-FAU molecular sieve, MOR type tin silicon molecular sieve is, for example, Sn-MOR molecular sieve. Further preferably, the tin silicon molecular sieve is an MFI type tin silicon molecular sieve.

[0036] In the third embodiment, when the skeleton metal element and the non-skeleton metal element are both Zr, the molecular sieve is a zirconium silicon molecular sieve, and the zirconium silicon molecular sieve is selected from one or more of MFI type zirconium silicon molecular sieve, MEL type zirconium silicon molecular sieve, BEA type zirconium silicon molecular sieve, MWW type zirconium silicon molecular sieve, FAU type zirconium silicon molecular sieve and MOR type zirconium silicon molecular sieve, MFI type zirconium silicon molecular sieve is, for example, Zr-MFI molecular sieve, MEL type zirconium silicon molecular sieve is, for example, Zr-MEL molecular sieve, BEA type zirconium silicon molecular sieve is, for example, Zr-Beta molecular sieve, MWW type zirconium silicon molecular sieve is, for example, Zr-MCM-22 molecular sieve, FAU type zirconium silicon molecular sieve is, for example, Zr-FAU molecular sieve, MOR type zirconium silicon molecular sieve is, for example, Zr-MOR molecular sieve. Further preferably, the zirconium silicon molecular sieve is an MFI type zirconium silicon molecular sieve. When the metal element is Hf or Pb, the same is true and will not be described in detail. The source of the molecular sieve is not limited and can be purchased from commercial sources or prepared using conventional techniques in the art.

[0037] In one embodiment, the molecular sieve includes one or more of a microporous molecular sieve, a hollow molecular sieve and an expanded pore molecular sieve; wherein the microporous molecular sieve refers to a molecular sieve having a micropore diameter of 0.4 to 0.7 nm, the hollow molecular sieve refers to an HTS molecular sieve, and the expanded pore molecular sieve refers to a molecular sieve having an average mesopore diameter of 8 to 35 nm.

[0038] In one embodiment of the present disclosure, the carbonyl compound raw material includes a first carbonyl compound and a second carbonyl compound, wherein the first carbonyl compound has a structure as shown in the following formula (1), and the second carbonyl compound has a cyclic ketone, and has a structure as shown in the following formula (1), formula (2) or formula (3):

[0039] Wherein, the R1-R2 are each independently selected from one or more of hydrogen, a halogen group, an alkyl group with 1 to 12 carbon atoms, a substituted or unsubstituted cycloalkyl group with 3 to 12 carbon atoms, a substituted or unsubstituted aryl group with 6 to 14 carbon atoms, and an alkoxy group with 1 to 12 carbon atoms; the R4-R6 are each independently selected from one or more of a halogen group, an alkyl group with 1 to 12 carbon atoms, a substituted or unsubstituted cycloalkyl group with 3 to 12 carbon atoms, a substituted or unsubstituted aryl group with 6 to 14 carbon atoms, and an alkoxy group with 1 to 12 carbon atoms; the R3, R7-R8 are each independently selected from one or more of hydrogen, an alkyl group with 1 to 12 carbon atoms, an alkoxy group with 1 to 12 carbon atoms, and a substituted or unsubstituted furyl group with 4 to 20 carbon atoms; the cyclic ketone is selected from a substituted or unsubstituted cyclic ketone with 4 to 8 carbon atoms.

[0040] In a preferred embodiment, the halogen group is selected from one or more of fluorine, chlorine, bromine and iodine, preferably chlorine; the alkyl group with 1 to 12 carbon atoms is selected from one or more of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl, neopentyl, 1,2-dimethylpropyl, isopentyl, n-hexyl, isohexyl, sec-hexyl, n-heptyl, isoheptyl, n-octyl, n-nonyl, n-decyl and n-dodecyl, preferably methyl.

[0041] The unsubstituted cycloalkyl group is selected from one or more of cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, cycloundecyl and cyclododecyl; the substituent on the substituted cycloalkyl group is selected from one or more of alkyl groups having 1 to 9 carbon atoms, preferably one or more of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl and tert-butyl; more preferably, the substituted or unsubstituted cycloalkyl group having 3 to 12 carbon atoms is selected from one or more of cyclopentyl, cyclohexyl and cycloheptyl.

[0042] The unsubstituted aryl group is selected from one or more of phenyl, naphthyl, anthracenyl and phenanthrenyl, wherein the substituent on the substituted aryl group is selected from an alkyl group having 1 to 8 carbon atoms, preferably one or more of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl and tert-butyl; more preferably, the substituted or unsubstituted aryl group having 6 to 14 carbon atoms is selected from one or more of phenyl, benzyl, propylphenyl and butylphenyl, further preferably phenyl.

[0043] The alkoxy group having 1 to 12 carbon atoms is selected from one or more of methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, n-pentoxy, isopentylpropoxy, n-hexyloxy and isohexyloxy, preferably one or more of methoxy, ethoxy, n-propoxy and n-butoxy.

[0044] The substituent on the substituted furanyl is selected from one or more of methyl, ethyl and hydroxymethyl; the unsubstituted cyclic ketone is selected from one or more of cyclopentanone, cyclohexanone and octacyclic ketone, wherein the substituent on the substituted cyclic ketone is selected from one or more of methyl, ethyl, n-propyl and isopropyl.

[0045] In the present disclosure, "substituted or unsubstituted cycloalkyl" refers to a cycloalkyl with a substituent or an unsubstituted cycloalkyl, and a substituted cycloalkyl may be a cycloalkyl in which one or more hydrogen atoms are replaced by a substituent; "substituted or unsubstituted aryl" refers to an aryl with a substituent or an unsubstituted aryl, and a substituted aryl may be an aryl in which one or more hydrogen atoms are replaced by a substituent; the number of carbon atoms of a substituted or unsubstituted group refers to the total number of carbon atoms. For example, if the aryl group is selected from a substituted phenyl group having 10 carbon atoms, the total number of carbon atoms of the phenyl group and the substituents thereon is 10.

[0046] In one embodiment of the present disclosure, the first carbonyl compound is selected from one or more of acetaldehyde, propionaldehyde, acetone, butanone, hexanone, methyl acetate, ethyl acetate, methyl propionate and methyl butyrate, preferably methyl propionate; the second carbonyl compound is selected from one or more of cyclohexanone, cyclopentanone, methyl acetate, ethyl acetate, methyl propionate, methyl butyrate, 2,2-dimethylpropionate, 2,2-dimethylpropionaldehyde, formaldehyde, benzaldehyde, furfural, 5-hydroxyfurfural and 5-methylfurfural, preferably formaldehyde.

[0047] In one embodiment of the present disclosure, the molar ratio of the first carbonyl compound to the second carbonyl compound is (0.5-10): 1, preferably (0.5-8): 1, and more preferably (0.5-5): 1. In the above embodiment, by selecting the preferred first carbonyl compound and the second carbonyl compound, the aldol condensation reaction is facilitated, and the raw material conversion rate and product selectivity are improved.

[0048] In one embodiment of the present disclosure, the reaction conditions further include: contacting the carbonyl compound raw material, the diluent and the catalyst and performing an aldol condensation reaction, wherein the diluent is selected from one or more of alcohols, ethers, alkanes and aromatic hydrocarbons, and the alcohols, ethers, alkanes and aromatic hydrocarbons are well known to those skilled in the art, preferably one or more of alcohols with carbon atoms of 1 to 12, ethers with carbon atoms of 1 to 12, alkanes with carbon atoms of 6 to 12 and aromatic hydrocarbons with carbon atoms of 6 to 20, more preferably one or more of methanol, ether, cyclohexane and toluene. The molar ratio of the diluent to the carbonyl compound raw material disclosed in the present disclosure can be adjusted arbitrarily. In one embodiment, the molar ratio of the diluent to the carbonyl compound raw material is (0.5 to 10): 1, preferably (0.5 to 5): 1, and more preferably (1 to 3): 1. In the above embodiment, by selecting a preferred content of the diluent, it is beneficial to inhibit the hydrolysis of the raw material methyl propionate and reduce the generation of propionic acid.

[0049] In one embodiment of the present disclosure, the reaction temperature is 200-500°C, preferably 250-480°C, more preferably 300-400°C; the reaction time is 0.2-24h, preferably 0.5-12h; the pressure is 0.01-2.4MPa, preferably 0.5-1MPa. The method of the present disclosure does not limit the heat source, and in principle any heat source can be used.

[0050] The reaction is carried out in a conventional reactor, and the present disclosure does not impose any special restrictions. For example, the reaction is carried out in a fixed bed reactor, a fluidized bed reactor or a tank reactor, and the reactor is a fixed bed reactor, and the mass liquid hourly space velocity of the reaction is 0.1 to 5 h based on the total volume of the carbonyl compound raw material and the diluent. -1 , preferably 0.1 to 2 hours -1 , more preferably 0.1 to 1 h -1 ; The reactor is a fluidized bed reactor, the weight ratio of the carbonyl compound raw material to the catalyst is (10-500):1, preferably (20-200):1; the reactor is a kettle reactor, the weight ratio of the carbonyl compound raw material to the catalyst is (1-200):1, preferably (2-50):1. The mass liquid hourly space velocity of the reaction refers to the mass of the mixed material flow passing through a unit mass of the catalyst per unit time.

[0051] It will be appreciated by those skilled in the art that, depending on the different reactors used, the catalyst disclosed herein may be a molecular sieve powder having skeleton metal elements and non-skeleton metal elements, or may be a shaped catalyst after the molecular sieve having skeleton metal elements and non-skeleton metal elements is mixed and shaped with a carrier. The separation of the product and the catalyst may be achieved in a variety of ways. For example, when the original powdered skeleton contains a tetravalent metal element molecular sieve as a catalyst, the separation of the product and the recycling of the catalyst may be achieved by sedimentation, filtration, centrifugation, evaporation, membrane separation, etc. Alternatively, the catalyst may be shaped and loaded into a fixed bed reactor, and the catalyst may be recovered after the reaction is completed. The separation and recovery methods of various catalysts are often involved in existing literature and will not be described here. The specific operation mode of the reactor is well known to those skilled in the art.

[0052] In one embodiment of the present disclosure, the reaction is carried out under at least one of an inert atmosphere, a gaseous hydrocarbon atmosphere and an oxygen-containing compound atmosphere, wherein the inert atmosphere includes one or more of nitrogen, helium and argon, and the oxygen-containing compound atmosphere includes carbon monoxide and / or carbon dioxide. The atmosphere can be supplied to the reaction process of the present disclosure from the outside, or the gas can be circulated in the reaction process by means of one or more circulation steps.

[0053] The present disclosure is further illustrated by the following examples, but the present disclosure is not limited thereto. Unless otherwise specified, the raw materials used in the examples and comparative examples of the present disclosure are purchased through commercial channels and are pure reagents.

[0054] The embodiments and comparative examples of the present disclosure adopt ultraviolet-visible spectroscopy to analyze framework metal elements and non-framework metal elements. The instrument model is Cary300 ultraviolet spectrophotometer, the manufacturer is Agilent, and the test conditions are: room temperature, normal pressure, the sample is tested after tabletting, and the scanning range is 190-800nm.

[0055] The types and contents of all metal elements and the content of silicon were determined using a ZSX100E X-ray fluorescence spectrometer produced by Rigaku Corporation of Japan. Test conditions: The samples were pressed into tablets and tested using tungsten-palladium, with an excitation voltage of 40 kV and an excitation current of 250 mA.

[0056] The acid content of B acid and L acid was measured by 2,6-di-tert-butylpyridine adsorption infrared acid method using a Vertex 70 instrument produced by Bruker Instruments. The specific method is as follows: the catalyst is pressed into a 10 mg / cm 2The thin slice was placed in an infrared cell with a CaF2 window, first evacuated at 400°C, then lowered to 50°C to adsorb 2,6-di-tert-butylpyridine for 15 minutes, then evacuated for 1 hour, lowered to room temperature to collect spectra, and calculated the acid amounts of B acid and L acid. See Applied Catalysis A: General, 294, 2005: 92.

[0057] The composition of the reaction product was analyzed by gas chromatography, and the analysis results were quantified by external standard method. The chromatographic analysis conditions were: Agilent-6890 chromatograph, HP-5 capillary column, injection volume 0.5 μL, injection port temperature 280°C; column temperature was maintained at 100°C for 2 min, then increased to 200°C at a rate of 15°C / min and maintained for 3 min. FID detector, detector temperature 300°C.

[0058] The particle size unit "mesh" in the present disclosure refers to the number of holes per inch on the screen used to screen different particle sizes. For example, 20 mesh means that there are 20 holes per inch on the screen, and 20-40 mesh refers to the particle size that can pass through the 20 mesh screen and be retained by the 40 mesh screen.

[0059] The preparation examples and the preparation comparative examples are used to provide catalysts used in the examples and comparative examples.

[0060] Preparation Example 1

[0061] Tetraethyl orthosilicate (TEOS), n-butyl titanate [Ti(OBu)4] and tetrapropylammonium hydroxide (TPAOH, 26.5wt%) solution were mixed in a molar ratio of SiO2: 0.1TiO2: 0.36TPAOH: 35H2O, and then stirred for 15 minutes to obtain a clear liquid. Finally, water was added to the clear liquid, stirred at 348-353K for about 3 hours to obtain a clear sol, and then crystallized at 443K for 3 days. After that, the obtained solid was filtered, washed with distilled water, dried at 373K for 5 hours, and then calcined at 823K for 10 hours to obtain Ti-MFI molecular sieve raw powder. The molecular sieve raw powder was pressed into sheets at a pressure of 20MPa, and particles of 20-40 mesh (i.e., an average particle size of 0.63-0.85mm) were screened as catalyst 1, denoted as C1, and its composition is shown in Table 1. The amount of TEOS used is 208.3 g, the amount of Ti(OBu)4 used is 34 g, the amount of TPAOH used is 286.0 g, and the amount of water used is 418.0 g.

[0062] The UV-visible spectrum of the prepared catalyst C1 is shown in Figure 1 As shown, from Figure 1It can be seen that C1 has framework metallic titanium and non-framework metallic titanium, among which the characteristic peak of framework tetracoordinate titanium species appears near a wavelength of 210 nm, the characteristic peak of framework hexacoordinate titanium species appears near a wavelength of 270 nm, and the characteristic peak of non-framework octahedral titanium dioxide appears near a wavelength of 330 nm.

[0063] The pyridine acid infrared spectrum of catalyst C1 is as follows Figure 2 As shown, from Figure 2 It can be seen that C1 is at 1540cm -1 There is no peak at the position of C1, indicating that C1 has no B acid site and its B acid content is 0 μmol·g -1 ; at 1446cm -1 The peak at 140.7 μmol·g indicates that C1 has L acid sites and its L acid content is 408.7 μmol·g -1 , the L acid site is beneficial to improving the raw material conversion rate and product selectivity.

[0064] Preparation Example 2

[0065] The same as Preparation Example 1, except that n-butyl titanate was replaced with zirconium n-propoxide (70 wt%) (C 12 H 28 O4Zr), the amount of zirconium n-propoxide is 46.8g, so that the materials are mixed according to the molar ratio of SiO2: 0.1ZrO2: 0.36TPAOH: 35H2O to obtain Zr-MFI molecular sieve raw powder, the molecular sieve raw powder is pressed into tablets under a pressure of 20MPa, and particles of 20-40 mesh (i.e., the average particle size is 0.63-0.85mm) are screened as catalyst 2, denoted as C2, and its composition is shown in Table 1.

[0066] Preparation Example 3

[0067] The same as Preparation Example 1, the only difference is: tetrapropylammonium hydroxide solution (TPAOH, 26.5wt%) is replaced by tetrabutylammonium hydroxide solution (TBAOH, 20wt%), the amount of TBAOH is 259.5g, so that the materials are mixed according to the molar ratio of SiO2: 0.1TiO2: 0.20TBAOH: 35H2O to obtain Ti-MEL molecular sieve raw powder, the molecular sieve raw powder is pressed into tablets at a pressure of 20MPa, and particles of 20 to 40 mesh (i.e., the average particle size is 0.63 to 0.85mm) are screened as catalyst 3, denoted as C3, and its composition is shown in Table 1.

[0068] Preparation Example 4

[0069] The same as Preparation Example 1, the only difference is that n-butyl titanate is replaced by zirconium n-propoxide (C 12 H 28O4Zr), tetrapropylammonium hydroxide solution (TPAOH, 26.5wt%) is replaced by tetrabutylammonium hydroxide solution (TBAOH, 20wt%), wherein the amount of zirconium n-propoxide is 46.8g, and the amount of TBAOH is 259.5g, so that the materials are mixed according to the molar ratio of SiO2:0.1ZrO2:0.20TBAOH:35H2O to obtain Zr-MEL molecular sieve raw powder, which is pressed into tablets at a pressure of 20MPa, and particles of 20-40 mesh (i.e., an average particle size of 0.63-0.85mm) are screened as catalyst 4, denoted as C4, and its composition is shown in Table 1.

[0070] Preparation Example 5

[0071] 20g of BEA molecular sieve with a silicon-aluminum ratio of 11 after calcination was mixed with a 13mol / L nitric acid aqueous solution, and the mixed solution was stirred at 90°C for 24h, washed with deionized water, dried and calcined to obtain a dealuminated molecular sieve; the dealuminated molecular sieve was mixed and stirred with 6.3g of titanium tetrachloride, filtered and dried, and calcined at 550°C for 3h to obtain Ti-BEA molecular sieve raw powder, which was pressed into sheets under a pressure of 20MPa, and particles of 20-40 mesh (i.e., an average particle size of 0.63-0.85mm) were screened as catalyst 5, denoted as C5, and its composition is shown in Table 1.

[0072] Preparation Example 6

[0073] The hollow titanium silicalite HTS prepared in this preparation example is prepared according to the method described in Example 1 of the specification of Chinese patent CN1301599A. The specific preparation method is as follows:

[0074] 22.5g of tetraethyl orthosilicate was mixed with 7.0g of tetrapropylammonium hydroxide, and 59.8g of distilled water was added. After mixing evenly, the mixture was hydrolyzed at normal pressure and 60°C for 1.0h to obtain a hydrolysis solution of tetraethyl orthosilicate. A solution consisting of 1.1g of tetrabutyl titanate and 5.0g of anhydrous isopropanol was slowly added under vigorous stirring. The resulting mixture was stirred at 75°C for 3h to obtain a clear and transparent colloid. The colloid was placed in a stainless steel sealed reactor and kept at a constant temperature of 170°C and autogenous pressure for 6 days to obtain a mixture of crystallized products; the mixture was filtered, washed with water to a pH of 6-8, and dried at 110°C for 60 minutes to obtain uncalcined TS-1 raw powder. The TS-1 raw powder was calcined at 550°C in air atmosphere for 4h to obtain TS-1 molecular sieve.

[0075] The obtained TS-1 molecular sieve was mixed evenly in the ratio of molecular sieve (g): sulfuric acid (mol): water (mol) = 100:0.15:150, reacted at 90°C for 5.0h, and then filtered, washed and dried according to conventional methods to obtain acid-treated TS-1 molecular sieve.

[0076] The acid-treated TS-1 molecular sieve was uniformly mixed in the ratio of molecular sieve (g): triethanolamine (mol): tetrapropylammonium hydroxide (mol): water (mol) = 100:0.20:0.15:180, placed in a stainless steel sealed reactor, and kept at a constant temperature of 190°C and autogenous pressure for 0.5 day. After cooling and depressurization, it was filtered, washed and dried according to a conventional method, and calcined at 550°C in air atmosphere for 3h to obtain HTS molecular sieve (having MFI structure) raw powder. The molecular sieve raw powder was pressed into tablets at a pressure of 20MPa, and particles of 20 to 40 mesh (i.e., an average particle size of 0.63 to 0.85mm) were screened as catalyst 6, denoted as C6, and its composition is shown in Table 1.

[0077] Preparation Example 7

[0078] The same as Preparation Example 1, the only difference is that n-butyl titanate is replaced by tin tetrachloride (SnCl4·5H2O), the amount of tin tetrachloride is 35.1g, so that the materials are mixed according to the molar ratio of SiO2:0.1SnO2:0.36TPAOH:35H2O to obtain Sn-MFI molecular sieve raw powder, the molecular sieve raw powder is pressed into tablets at a pressure of 20MPa, and particles of 20 to 40 mesh (i.e., the average particle size is 0.63 to 0.85mm) are screened as catalyst 7, denoted as C7, and its composition is shown in Table 1.

[0079] Preparation Example 8

[0080] The same as Preparation Example 1, the only difference is that n-butyl titanate is replaced by hafnium isopropoxide, the amount of hafnium isopropoxide is 47.5 g, so that the materials are mixed in a molar ratio of SiO2: 0.1HfO2: 0.36TPAOH: 35H2O to obtain Hf-MFI molecular sieve raw powder, the molecular sieve raw powder is pressed into tablets at a pressure of 20 MPa, and particles of 20 to 40 mesh (i.e., an average particle size of 0.63 to 0.85 mm) are screened as catalyst 8, denoted as C8, and its composition is shown in Table 1.

[0081] Preparation Example 9

[0082] The same as Preparation Example 1, the only difference is: n-butyl titanate is replaced by lead nitrate (Pb(NO3)2), the amount of lead nitrate is 33.1g, so that the materials are mixed in a molar ratio of SiO2:0.1PbO:0.36TPAOH:35H2O to obtain Pb-MFI molecular sieve raw powder, the molecular sieve raw powder is pressed into tablets at a pressure of 20MPa, and particles of 20-40 mesh (i.e., an average particle size of 0.63-0.85mm) are screened as catalyst 9, denoted as C9, and its composition is shown in Table 1.

[0083] Preparation Comparative Example 1

[0084] This comparative preparation example is prepared according to the method of the literature M.Ai.Applied Catalysis A: General 288 (2005) 211-215 to prepare Cs-loaded amorphous silica molecular sieve. The specific preparation method is as follows:

[0085] The excess water in the aqueous SiO2 colloid (20%) is evaporated to obtain a silica dry gel; the dry gel is ground and sieved to obtain a solid with a size of 8 to 20 meshes. The obtained solid is calcined at 400°C for 4 hours, and then impregnated with an aqueous solution (2 mol / L) containing the required amount of cesium hydroxide. The wet gel is dried in an oven and calcined again at 400°C in an air flow for 6 hours to obtain Cs / SiO2 molecular sieve raw powder, which is pressed into tablets at a pressure of 20 MPa, and particles of 20 to 40 meshes (i.e., an average particle size of 0.63 to 0.85 mm) are screened as comparative catalyst 1, denoted as D1, and its composition is shown in Table 1.

[0086] Preparation Comparative Example 2

[0087] The preparation method is the same as that of comparative example 1, except that the cesium hydroxide aqueous solution is replaced by the same amount of n-butyl titanate to obtain Ti / SiO2 molecular sieve raw powder, which is pressed into tablets at a pressure of 20 MPa, and particles of 20 to 40 mesh (i.e., an average particle size of 0.63 to 0.85 mm) are screened as comparative catalyst 2, denoted as D2, and its composition is shown in Table 1.

[0088] Preparation Comparative Example 3

[0089] A measured solution of tetrapropylammonium hydroxide (TPAOH, 26.5wt%) was added to a solution of tetraethyl orthosilicate (TEOS) to obtain a liquid mixture with a pH of about 13, and then stirred for 3 hours under vigorous stirring to obtain a clear liquid, and then stirred for about 3 hours at 348-353K to obtain a sol with a chemical composition of SiO2: 0.36TPAOH: 35H2O, and then crystallized at 443K for 3 days, after which the obtained solid was filtered, washed with distilled water, dried at 373K for 5 hours, and then calcined at 823K for 10 hours to obtain a full-silicon S-MFI molecular sieve. Among them, the amount of TEOS used is 208.3g, the amount of TPAOH used is 286g, and the amount of water used is 73g;

[0090] 2.85g of titanium tetrachloride was dissolved in ethanol, then impregnated with an equal volume of S-MFI molecular sieve, and dried at 110°C for 2h. After the mixture was dried, it was placed in a muffle furnace and calcined at 400°C for 4h to obtain the impregnated supported D-Ti-MFI-1 molecular sieve raw powder, which was pressed into sheets at a pressure of 20MPa, and particles of 20-40 mesh (i.e., an average particle size of 0.63-0.85mm) were screened as comparative catalyst 3, denoted as D3, and its composition is shown in Table 1. The molar ratio of titanium tetrachloride to S-MFI molecular sieve is 0.015.

[0091] Preparation Comparative Example 4

[0092] The same as Preparation Example 1, the only difference is that the amount of n-butyl titanate [Ti(OBu)4] used is 3.4 g, so that the materials are mixed in a molar ratio of SiO2: 0.01TiO2: 0.36TPAOH: 35H2O to obtain D-Ti-MFI-2 molecular sieve raw powder, which is pressed into tablets at a pressure of 20 MPa, and particles of 20 to 40 mesh (i.e., an average particle size of 0.63 to 0.85 mm) are screened as comparative catalyst 4, denoted as D4, and its composition is shown in Table 1.

[0093] The UV-visible spectrum of D4 is as follows: Figure 3 As shown, from Figure 3 It can be seen that D4 only has the characteristic peak of framework tetracoordinated titanium species near the wavelength of 210 nm, indicating that D4 only contains framework titanium but not non-framework titanium.

[0094] Table 1

[0095]

[0096]

[0097] “-” means that the species is not contained or the content of the species is 0.

[0098] The following examples and comparative examples are used to illustrate the method of preparing α,β-unsaturated carbonyl compounds by catalyzing carbonyl compound raw materials with different catalysts.

[0099] Example 1

[0100] The catalyst 1 prepared in Preparation Example 1 was loaded into a fixed bed reactor and preactivated. The preactivation conditions were as follows: the N2 flow rate was 30 mL / min, the temperature was raised to 400°C at a rate of 2°C / min, and the temperature was kept constant at 400°C for 5 hours, and then the temperature was lowered to the desired reaction temperature of 360°C in a nitrogen atmosphere. Formaldehyde, methyl propionate and methanol were fed into the bed of the reaction section through N2, wherein the reaction temperature was 360°C, the reaction time was 2 hours, the reaction pressure was 0.5 MPa, the molar ratio of formaldehyde to methyl propionate was 1:5, the molar ratio of methanol to methyl propionate was 1.5:1, and the mass liquid hourly space velocity of the reaction feed was 0.8 h based on the total volume of formaldehyde, methyl propionate and methanol. -1 The results of the aldol condensation reaction are shown in Table 2. The conversion rate of methyl propionate and the selectivity of methyl methacrylate are calculated according to the following formulas (1) to (2):

[0101]

[0102]

[0103] Embodiments 2 to 9

[0104] The aldol condensation reaction was carried out according to the method and reaction conditions of Example 1, and the catalysts prepared in Preparation Examples 2 to 9 were used to catalyze the aldol condensation reaction. The reaction results are shown in Table 2.

[0105] Embodiments 10 to 20

[0106] The aldol condensation reaction was carried out according to the method of Example 1. The catalyst and reaction conditions used are shown in Table 3.

[0107] Comparative Examples 1 to 4

[0108] The aldol condensation reaction was carried out according to the method and reaction conditions of Example 1, and the aldol condensation reaction was catalyzed by the comparative catalysts prepared in Comparative Preparation Examples 1 to 4. The reaction results are shown in Table 2.

[0109] Comparative Examples 5 to 11

[0110] The aldol condensation reaction was carried out according to the method of Example 1. The comparative catalyst and reaction conditions used are shown in Table 3.

[0111] Table 2

[0112]

[0113] Table 3

[0114]

[0115] It can be seen from the results of the above embodiments and comparative examples that when the method of the present invention is used to prepare α,β-unsaturated carbonyl compounds, and the content of the framework metal element in the molecular sieve is limited to 10-80 mol%, the content of the non-framework metal element is 20-90 mol%, and the molar ratio of the non-framework metal element to the framework metal element is (0.25-9):1, it is beneficial to improve the conversion rate of methyl propionate and the selectivity of methyl methacrylate, and the operation process is simple.

[0116] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0117] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0118] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A method for preparing an α,β-unsaturated carbonyl compound, characterized in that: The method comprises: contacting a carbonyl compound raw material and a catalyst to carry out an aldol condensation reaction, wherein the carbonyl compound raw material comprises one or more of aldehydes, ketones and esters, and the catalyst comprises a molecular sieve having a metal element, wherein the metal element is selected from one or more of Ti, Zr, Hf, Sn and Pb; The metal elements include skeleton metal elements and non-skeleton metal elements. Based on the total molar number of all metal elements in the molecular sieve, the content of the skeleton metal elements is 10-80 mol%, and the content of the non-skeleton metal elements is 20-90 mol%. The molar ratio of the non-skeleton metal elements to the skeleton metal elements is (0.25-9):1, wherein the content of the metal elements is calculated as metal oxides.

2. The method according to claim 1, characterized in that The total acid content of B acid of the catalyst measured by pyridine adsorption infrared method at 50°C is 50 μmol·g -1 Below, preferably 5 μmol·g -1 Below, more preferably 0 μmol·g -1 ; L acid total acid content is 50~1000μmol·g -1 , preferably 300 to 800 μmol·g -1 .

3. The method according to claim 1, characterized in that Based on the total molar number of all metal elements in the molecular sieve, the content of the framework metal element is 10 to 50 mol%, preferably 10 to 30 mol%; the content of the non-framework metal element is 50 to 90 mol%, preferably 50 to 80 mol%; The molar ratio of the non-framework metal elements to the framework metal elements is (1-7):1, preferably (2-5):1, and more preferably (3-4):1; the molar ratio of the framework metal elements to the silicon element in the molecular sieve is (0.005-0.5):1, preferably (0.02-0.2):1, and more preferably (0.02-0.15):1, wherein the content of the silicon element is calculated as SiO2.

4. The method according to claim 1, characterized in that: The molecular sieve is one or more selected from MFI type molecular sieve, MEL type molecular sieve, BEA type molecular sieve, MWW type molecular sieve, FAU type molecular sieve and MOR type molecular sieve, preferably one or more selected from MFI type molecular sieve, MEL type molecular sieve and BEA type molecular sieve.

5. The method according to claim 1, characterized in that: The carbonyl compound raw material includes a first carbonyl compound and a second carbonyl compound, wherein the first carbonyl compound has a structure as shown in the following formula (1), and the second carbonyl compound has a cyclic ketone, and has a structure as shown in the following formula (1), formula (2) or formula (3): Wherein, each of R1 to R2 is independently selected from one or more of hydrogen, a halogen group, an alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 12 carbon atoms, a substituted or unsubstituted aryl group having 6 to 14 carbon atoms, and an alkoxy group having 1 to 12 carbon atoms; The R4 to R6 are each independently selected from one or more of a halogen group, an alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 12 carbon atoms, a substituted or unsubstituted aryl group having 6 to 14 carbon atoms, and an alkoxy group having 1 to 12 carbon atoms; The R3, R7-R8 are each independently selected from one or more of hydrogen, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, and a substituted or unsubstituted furyl group having 4 to 20 carbon atoms; The cyclic ketone is selected from substituted or unsubstituted cyclic ketones having 4 to 8 carbon atoms; Preferably, the halogen group is selected from one or more of fluorine, chlorine, bromine and iodine, preferably chlorine; The alkyl group having 1 to 12 carbon atoms is one or more selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl, neopentyl, 1,2-dimethylpropyl, isopentyl, n-hexyl, isohexyl, sec-hexyl, n-heptyl, isoheptyl, n-octyl, n-nonyl, n-decyl and n-dodecyl, and is preferably methyl; The unsubstituted cycloalkyl group is selected from one or more of cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, cycloundecyl and cyclododecyl; the substituent on the substituted cycloalkyl group is selected from one or more of alkyl groups having 1 to 9 carbon atoms, preferably one or more of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl and tert-butyl; more preferably, the substituted or unsubstituted cycloalkyl group having 3 to 12 carbon atoms is selected from one or more of cyclopentyl, cyclohexyl and cycloheptyl; The unsubstituted aryl group is selected from one or more of phenyl, naphthyl, anthracenyl and phenanthrenyl, wherein the substituent on the substituted aryl group is selected from an alkyl group having 1 to 8 carbon atoms, preferably one or more of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl and tert-butyl; more preferably, the substituted or unsubstituted aryl group having 6 to 14 carbon atoms is selected from one or more of phenyl, benzyl, propylphenyl and butylphenyl, further preferably phenyl; The alkoxy group having 1 to 12 carbon atoms is selected from one or more of methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, n-pentoxy, isopentylpropoxy, n-hexyloxy and isohexyloxy, preferably one or more of methoxy, ethoxy, n-propoxy and n-butoxy; The substituent on the substituted furanyl group is selected from one or more of methyl, ethyl and hydroxymethyl; The unsubstituted cyclic ketone is selected from one or more of cyclopentanone, cyclohexanone and octacyclic ketone, wherein the substituent on the substituted cyclic ketone is selected from one or more of methyl, ethyl, n-propyl and isopropyl.

6. The method according to claim 5, characterized in that The first carbonyl compound is selected from one or more of acetaldehyde, propionaldehyde, acetone, butanone, hexanone, methyl acetate, ethyl acetate, methyl propionate and methyl butyrate, preferably methyl propionate; the second carbonyl compound is selected from one or more of cyclohexanone, cyclopentanone, methyl acetate, ethyl acetate, methyl propionate, methyl butyrate, 2,2-dimethylpropionate, 2,2-dimethylpropionaldehyde, formaldehyde, benzaldehyde, furfural, 5-hydroxyfurfural and 5-methylfurfural, preferably formaldehyde.

7. The method according to claim 5, characterized in that The molar ratio of the first carbonyl compound to the second carbonyl compound is (0.5-10):1, preferably (0.5-8):1, and more preferably (0.5-5):

1.

8. The method according to claim 1, characterized in that: The reaction conditions also include: contacting a carbonyl compound raw material, a diluent and a catalyst to carry out an aldol condensation reaction, wherein the diluent is selected from one or more of alcohols, ethers, alkanes and aromatic hydrocarbons, preferably one or more of alcohols with 1 to 12 carbon atoms, ethers with 1 to 12 carbon atoms, alkanes with 6 to 12 carbon atoms and aromatic hydrocarbons with 6 to 20 carbon atoms, more preferably one or more of methanol, ether, cyclohexane and toluene; The molar ratio of the diluent to the carbonyl compound raw material is (0.5-10):1, preferably (0.5-5):1, and more preferably (1-3):

1.

9. The method according to claim 8, characterized in that The reaction temperature is 200-500°C, preferably 250-480°C, more preferably 300-400°C; the reaction time is 0.2-24h, preferably 0.5-12h; the pressure is 0.01-2.4MPa, preferably 0.5-1MPa; The reaction is carried out in a reactor, which includes a fixed bed reactor, a fluidized bed reactor or a tank reactor; the reactor is a fixed bed reactor, and the mass liquid hourly space velocity of the reaction is 0.1 to 5 h based on the total volume of the carbonyl compound raw material and the diluent. -1 , preferably 0.1 to 2 hours -1 , more preferably 0.1 to 1 h -1 ; The reactor is a fluidized bed reactor, and the weight ratio of the carbonyl compound raw material to the catalyst is (10-500):1, preferably (20-200):1; The reactor is a kettle reactor, and the weight ratio of the carbonyl compound raw material to the catalyst is (1-200):1, preferably (2-50):

1.

10. The method according to claim 1, characterized in that The reaction is carried out in an inert atmosphere or an oxygen-containing compound atmosphere, wherein the inert atmosphere includes one or more of nitrogen, helium and argon, and the oxygen-containing compound atmosphere includes carbon monoxide and / or carbon dioxide.

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