A catalyst for aldol condensation reaction, a preparation method and application thereof

Abstract

A catalyst for aldol condensation reaction, characterized by containing silicon, oxygen and alkali metal elements, having an amorphous structure, a micropore volume less than 0.05 cm 3 / g, a mesopore volume greater than 0.55 cm 3 / g, a clear pore distribution in the range of 16-50 nm, a specific surface area of 50-300 m 2 / g, a ratio of mesopore volume to total pore volume of (0.9-0.99):1, and the catalyst is characterized by NMR silicon spectrum, a ratio Q 4 / Q 3 >100, wherein Q 4 represents Si(OSi)4 species, and Q 3 represents Si(OSi)3(OH) species.

Description

Technical Field

[0001] The present invention relates to the technical field of organic chemical reactions, and more particularly to an aldol condensation reaction catalyst, a preparation method and an aldol condensation reaction thereof. Background Art

[0002] Methyl acrylate is an important organic intermediate widely used in industries such as rubber, leather, pharmaceuticals, and coatings. Currently, there are several main methods for producing methyl acrylate: propylene oxidation, acrylonitrile hydrolysis, and propane oxidation. Industrial production is primarily based on propylene oxidation, which offers technical and economic advantages but is inefficient. Acrylonitrile hydrolysis produces low yields and cannot recycle sulfuric acid. Propane oxidation, a commonly used method, is inexpensive but offers low product yields.

[0003] The preparation of methyl acrylate by the condensation reaction of coal-based methyl acetate (or acetic acid) and formaldehyde is a very important and highly productive process synthesis route. It not only has low production costs but also effectively controls the discharge of polluted waste liquids, making it a synthesis method with great application prospects.

[0004] Chemical Industry Progress, 2021, 40(4): 2005-2015 reports on the research progress of acetic acid (ester)-formaldehyde condensation to acrylic acid (ester). The catalysts currently used in this route include VPO catalysts, alkali metal / alkaline earth metal catalysts and ionic liquid catalysts. Among them, VPO catalysts have high catalytic efficiency, but many side reactions and are easily deactivated. Compared with VPO, alkali metal catalysts have no oxidative by-products and higher selectivity, but their catalytic efficiency is slightly lower. Ionic liquid catalysts have mild reaction conditions and high selectivity, but product separation is difficult and the catalyst is difficult to reuse. In comparison, the preparation process of alkali metal catalysts is simpler, the adjustable space is large, the product selectivity is high, and it is easier to achieve industrial application.

[0005] CN 108097290A reports a catalyst for preparing acrylic acid / methyl acrylate from raw materials containing carbon monoxide and formaldehyde compounds. The catalyst is primarily obtained by metal-modifying commercially available MOR molecular sieves with varying silicon-to-aluminum ratios with at least one of copper, silver, iron, cobalt, nickel, and gallium through impregnation, ion exchange, and in-situ synthesis. The catalyst achieves a maximum selectivity of 88.2% for acrylic acid and 5.3% for methyl acrylate.

[0006] The catalyst reported in CN 106693941A contains Li, Na, K, Rb, Cs, Mg, Ca, Sr, and Ba as active components, and Al2O3 prepared by coprecipitation as a carrier. At a molar ratio of methyl acetate: formaldehyde: methanol of 1:2:2, the conversion of methyl acetate was 34.4%, and the selectivity for methyl acrylate was 93.4%.

[0007] CN 104258901A discloses a Cs-loaded pure silicon molecular sieve catalyst, which uses KIT-6 as a carrier and different contents of Cs as an active component. The catalyst is used in the aldol condensation reaction of methyl acetate and formaldehyde to prepare methyl acrylate. The molar ratio of methyl acetate, formaldehyde, and methanol is 1:2:2. The conversion rate of methyl acetate can reach up to 35%, and the selectivity of methyl acrylate can reach up to 94%.

[0008] Teng He et al. reported in Catalysis Letters, 2019, 149(2):373-389 that cesium-loaded SiO2 was used as a catalyst and different contents of Cs as the active component in the reaction of methyl acetate and formaldehyde aldol condensation to prepare methyl acrylate. The molar ratio of methyl acetate, formaldehyde, and methanol was 1:2:2. At a reaction temperature of 390°C, the conversion rate of methyl acetate was about 35%, and the selectivity of methyl acrylate was 85-90%.

[0009] Among various catalysts for catalyzing the aldol condensation reaction of methyl acetate and formaldehyde to prepare MA, silica-supported Cs alkali metal catalyst has the best performance, but its activity is not ideal and the yield of the target product is low. Summary of the Invention

[0010] The present invention aims to provide an aldol condensation reaction catalyst having high catalytic activity and high yield of target product, a preparation method thereof and application of the catalyst in the aldol condensation reaction.

[0011] In order to achieve the above object, the present invention provides an aldol condensation reaction catalyst, characterized in that it contains silicon, oxygen and alkali metal elements, has an amorphous structure, and a micropore volume of less than 0.05 cm 3 / g, mesopore volume greater than 0.55cm 3 / g, with obvious pore distribution in the range of 16-50nm and a specific surface area of ​​50-300m 2 / g, and the ratio of mesopore volume to total pore volume is (0.9-0.99):1.

[0012] The present invention also provides a method for preparing an aldol condensation reaction catalyst, which is characterized in that silicon dioxide is mixed with an alkali metal hydroxide or salt and an optionally added solvent, the mixture is stirred or ground to be uniform, and then treated under steam conditions, and finally the treated solid is dried and calcined.

[0013] The present invention further provides an aldol condensation method, characterized in that, in the presence of the catalyst provided by the present invention or the catalyst obtained by the preparation method provided by the present invention, a carbonyl-containing compound having an α-H group undergoes a carbon-carbon bond coupling reaction with another carbonyl-containing compound to generate a carbonyl-containing compound having a β-hydroxy group or a carbonyl-containing compound having an α,β-unsaturated bond.

[0014] Compared with the prior art, the advantages of the present invention are:

[0015] (1) The catalyst prepared by stirring or grinding with alkali metal as the main active component and silica as the carrier has a very high mesoporous ratio, which can provide a rich mesoporous specific surface area to immobilize active centers, and can make the alkali metal evenly distributed in the carrier silica, thereby ensuring good selectivity of the catalyst while improving activity.

[0016] (2) The catalyst preparation method is simple, has a short number of steps, and the raw materials are widely available and inexpensive, making it suitable for large-scale industrial applications and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The XRD spectra of Example 1 and Example 7 are shown in FIG.

[0018] Figure 2 The pore distribution diagrams of Example 1, Example 7 and Comparative Example 2 are shown. DETAILED DESCRIPTION

[0019] The present invention provides an aldol condensation reaction catalyst, characterized in that it contains silicon, oxygen and alkali metal elements, has an amorphous structure, and has a micropore volume of less than 0.05 cm 3 / g, mesopore volume greater than 0.55cm 3 / g, with obvious pore distribution in the range of 16-50nm and a specific surface area of ​​50-300m 2 / g, and the ratio of mesopore volume to total pore volume is (0.9-0.99):1.

[0020] The catalyst provided by the present invention is characterized by XRD as an amorphous structure, that is, there are no obvious sharp characteristic peaks in the spectrum; XRF characterization shows that it contains silicon, oxygen and alkali metal elements. The catalyst is characterized by N2 adsorption and desorption method, and the BET specific surface area is 50-300m 2 / g, preferably 70-250m 2 / g, more preferably 90-200m 2 / g, more preferably 100-160m 2 / g. The aldol condensation reaction catalyst provided by the present invention has an extremely high mesopore ratio, which can provide abundant mesopore specific surface area for immobilized active centers. The ratio of the mesopore volume to the total pore volume of the catalyst is (0.9-0.99):1, preferably (0.95-0.99):1, and further preferably (0.98-0.99):1.

[0021] In the catalyst provided by the present invention, the alkali metal element is selected from one or more of lithium, sodium, potassium, rubidium, and cesium, preferably one or more of potassium, rubidium, and cesium, more preferably one or more of rubidium and cesium, and even more preferably cesium. Preferably, the alkali metal element is uniformly dispersed in the silica.

[0022] The catalyst provided by the present invention has a molar ratio of each element in the catalyst obtained by X-ray fluorescence spectrometry (XRF). The molar ratio of the alkali metal element to the silicon element is (0.001-0.1):1, preferably (0.005-0.08):1, further preferably (0.01-0.06):1, and even more preferably (0.02-0.05):1.

[0023] The catalyst provided by the present invention has a pore volume of less than 0.05 cm 3 / g, preferably less than 0.03cm 3 / g, more preferably less than 0.02cm 3 / g; mesopore volume is greater than 0.55cm 3 / g, preferably greater than 0.60cm 3 / g, more preferably greater than 0.70cm 3 / g, and a large mesopore volume is beneficial to the efficient distribution of active centers; the catalyst provided by the present invention has an obvious pore distribution in the range of 16-50nm.

[0024] In the catalyst provided by the present invention, the ratio of the substrate specific surface area to the micropore specific surface area is preferably (1-7):1, further preferably (2-6):1, and more preferably (3-5):1. The substrate is the non-micropore part, and the specific surface area of ​​the substrate = BET specific surface area - specific surface area of ​​the micropores

[0025] In the Si NMR spectrum, Q 4 (-113ppm) represents Si(OSi)4 species, Q 3 (-103ppm) represents Si(OSi)3(OH) species. Characterized by NMR silicon spectrum, it can be found that the catalyst provided by the present invention has a low Q 3 The signal intensity of silicon species indicates that there are fewer defect sites and the active centers are more evenly dispersed, which is more conducive to the catalytic reaction Q 4 With Q 3The ratio of the signal peak height is greater than 100:1, preferably greater than 150:1, further preferably greater than 200:1, more preferably greater than 250:1, and most preferably 300:1 until there is no Q 3 Signal peak.

[0026] The present invention also provides a method for preparing the above-mentioned aldol condensation reaction catalyst, characterized in that silicon dioxide is mixed with an alkali metal hydroxide or salt and an optionally added solvent, the mixture is stirred or ground to be uniform, and then treated under steam conditions. Finally, the treated solid is dried and calcined to obtain the catalyst.

[0027] In the preparation method, the silicon dioxide is derived from white carbon black or silicon dioxide produced by hydrolysis and precipitation of organic silicone ester. The white carbon black preferably has a SiO2 weight content greater than 99%, more preferably greater than 99.9%; the specific surface area of ​​the white carbon black is preferably 50-1000m 2 / g, more preferably 100-800m 2 / g, more preferably 150-500m 2 / g. Hydrophilic silica is preferred. Compared to other types of silica, such as oleophilic silica, hydrophilic silica is more convenient for handling during preparation and loading of active centers.

[0028] The organosilicon ester is preferably tetraalkoxysilane. Tetraalkoxysilane has a structure of R1, R2, R3, R4 (SiO4), wherein R1, R2, R3, R4 are independently C1-C 12 alkyl, alkenyl, alkynyl, or aryl substituted groups, and each R group is connected to an oxygen atom of silicon. Preferably, R1, R2, R3, and R4 are independently C2-C4 alkyl, alkenyl, alkynyl, or aryl substituted groups, further preferably, R1, R2, R3, and R4 are C2-C4 alkyl, alkenyl, alkynyl, or aryl substituted groups, more preferably, R1, R2, R3, and R4 are C2-C4 alkyl substituted groups, most preferably, R1, R2, R3, and R4 are ethyl or propyl groups. Specifically, the tetraalkoxysilane can be one or more of tetraethoxysilane and tetrapropoxysilane.

[0029] The hydrolysis and precipitation of the organosilicon ester can be carried out under acidic conditions, such as pH 6, 5, 4, 3, 2, or 1, or under alkaline conditions, such as pH 8, 9, 10, 11, 12, 13, or 14. The acidic conditions can be provided by inorganic acids and / or organic acids, such as one or more of hydrochloric acid, nitric acid, phosphoric acid, sulfuric acid, acetic acid, and propionic acid. The alkaline conditions can be provided by inorganic bases and / or organic bases, such as one or more of ammonium hydroxide, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium phosphate, methylamine, ethylamine, propylamine, butylamine, cyclohexylamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, and tetrabutylphosphine hydroxide.

[0030] The hydrolysis can be carried out in water or in a solution containing water, for example, a methanol-water solution. The hydrolysis process can generally be carried out at room temperature and pressure. Appropriately increasing the temperature can accelerate the hydrolysis process, for example, at temperatures above 30°C. The hydrolysis is generally completed within 0.1-24 hours, and the hydrolysis time can be adjusted as needed.

[0031] Typically, a solid precipitate is produced after hydrolysis, which can be separated by conventional methods such as filtration and centrifugation to obtain a precipitate. At this point, the precipitate can be used directly for subsequent operations, or can be dried before subsequent operations, or can be dried and calcined before subsequent operations. Preferably, subsequent operations are performed after drying. The drying is preferably carried out at a temperature range of 60-150°C, more preferably 80-150°C, and more preferably 100-130°C, and the drying time is preferably 0.1-24h, more preferably 0.5-12h, and more preferably 1-6h. The calcination is preferably carried out at 350-750°C for 0.5-12h, and the calcination atmosphere is preferably an oxygen-containing atmosphere, and more preferably an air atmosphere.

[0032] In the preparation method, the alkali metal is selected from one or more of lithium, sodium, potassium, rubidium, and cesium, preferably one or more of potassium, rubidium, and cesium, more preferably one or more of rubidium and cesium, and even more preferably cesium. The alkali metal element is uniformly dispersed in the catalyst.

[0033] In the preparation method, the alkali metal hydroxide or salt includes alkali metal hydroxide, hydrochloride, hypochlorite, chlorite, metachlorate, perchlorate, nitrate, sulfate, bisulfate, sulfite, bisulfite, phosphate, hydrogen phosphate, dihydrogen phosphate, high phosphate, metaphosphate, phosphite, hypophosphite, carboxylate, pyrophosphate, ammonium salt, C1-C 20One or more of the carboxylates of cesium; preferably nitrates, carbonates, hydroxides of alkali metals; more preferably one or more of cesium hydroxide, cesium nitrate, cesium carbonate, cesium bicarbonate, and cesium acetate.

[0034] In the preparation method, the molar ratio of silicon dioxide (calculated as SiO2) to alkali metal is preferably 1:(0.001-0.1), further preferably 1:(0.005-0.08), more preferably 1:(0.01-0.06), and most preferably 1:(0.02-0.05).

[0035] In the preparation method, the solvent is optional. The solvent can be an inorganic solvent or an organic solvent. The inorganic solvent is distilled water or deionized water; the organic solvent includes an organic solvent selected from C1-C 10 Alcohol, C3-C 10 Ketone, C2-C 10 Esters, C6-C 10 The solvent may also be a chlorinated solvent such as dichloromethane. The solvent is an aliphatic alcohol, typically a C1-C6 alkanol, such as methanol, ethanol, propanol, isopropanol, butanol, pentanol, and hexanol, preferably methanol, ethanol, or propanol. The amount of solvent added depends on the carrier. In the preparation method, the preferred solvent is at least one of water, methanol, ethanol, and propanol. The molar ratio of silicon dioxide (calculated as SiO2) to solvent is preferably 1:(0-10), more preferably 1:(0.5-7), and more preferably 1:(1-4).

[0036] In the preparation method, the mixing is uniform, and one or more of stirring method, impregnation method, ion exchange method, spraying method, solid phase ion exchange method and grinding method can be used, and can be reused many times, among which stirring method or grinding method is preferred. Compared with other methods, the grinding method can make the alkali metal and silica better contact, and a grinding chemical reaction occurs, which is more conducive to the formation of the catalytic active center of the present invention, so the grinding method is more preferred. The grinding is preferably carried out at 20-150°C, more preferably 30-100°C, and more preferably 40-70°C for 5-120min, preferably 10-80min, and more preferably 15-60min; the grinding can be carried out at a pressure (gauge pressure) of -0.1-5MPa. Both negative pressure and positive pressure conditions are conducive to the distribution of alkali metal elements, but it also brings the problem of high energy consumption.

[0037] In the preparation method, the treatment under steam conditions is carried out at a temperature of 100-200°C, preferably 120-180°C, and more preferably 130-160°C, with water vapor at a gauge pressure of 0-1 MPa, preferably 0.1-0.8 MPa, and more preferably 0.3-0.6 MPa, for 0.1-24 hours, preferably 1-12 hours, and even more preferably 2-8 hours. The steam can be superheated steam or saturated steam. The pressure can be adjusted by supplementing gases such as nitrogen, argon, and air. Treatment under steam conditions can increase the mesopore volume, promote the distribution of alkali metal elements, and form efficient active centers.

[0038] In the preparation method, the treated solid is dried and calcined, wherein the drying condition is 60-150°C, preferably in the temperature range of 80-130°C. The drying time is 0.5-24h, preferably 0.5-12h, more preferably 1-6h. In the calcination conditions, the calcination temperature is determined according to the decomposition temperature of the modifier alkali element precursor, but is preferably <550°C to prevent the alkali element precursor from decomposing. The calcination temperature is further preferably 400-550°C. To prevent significant changes in the carrier structure or specific surface area, the calcination time is 0.5-12h, preferably 3-8h; the calcination atmosphere is preferably an oxygen-containing atmosphere, and more preferably an air atmosphere.

[0039] The present invention further provides an aldol condensation method, characterized in that, in the presence of the catalyst provided by the present invention or the catalyst obtained by the preparation method provided by the present invention, a carbonyl-containing compound having an α-H group undergoes a carbon-carbon bond coupling reaction with another carbonyl-containing compound to generate a carbonyl-containing compound having a β-hydroxy group or a carbonyl-containing compound having an α,β-unsaturated bond.

[0040] The α and β positions refer to the functional groups of hydrocarbon molecules, such as carbonyl, hydroxyl, carboxyl, etc., and their first ortho and second ortho carbon atoms. Wherein, the carbonyl-containing compound includes the first carbonyl compound and the second carbonyl compound, and the number of carbon atoms is preferably C1-C 20 The carbonyl compound may include the following structure:

[0041] C1-C 12Alkyl groups such as 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 C1-C6 alkyl groups such as 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, particularly preferably C1-C4 alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isohexyl, sec-butyl and tert-butyl.

[0042] C3-C 12 Cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, cycloundecyl and cyclododecyl; preferably cyclopentyl, cyclohexyl and cycloheptyl.

[0043] Examples of substituted cycloalkyl groups are: 2-methylcyclopentyl, 3-methylcyclopentyl, 2-methylcyclohexyl, 3-methylcyclohexyl, 4-methylcyclohexyl, 2-methoxycyclopentyl, 2-chlorocyclopentyl, 2-methylthiocyclohexyl and other derivatives.

[0044] C7-C 13 Arylalkyl, preferably C7-C 12 Phenylalkyl, such as benzyl, 1-phenylethyl, 2-phenylethyl, 1-phenylpropyl, 2-phenylpropyl, 3-phenylpropyl, 1-phenylbutyl, 2-phenylbutyl, 3-phenylbutyl and 4-phenylbutyl, particularly preferably benzyl;

[0045] C6-C 14 Aryl, for example phenyl, 1-naphthyl, 2-naphthyl, 1-anthryl, 2-anthryl, 9-anthryl, 1-phenanthrenyl, 2-phenanthrenyl, 3-phenanthrenyl, 4-phenanthrenyl, 9-phenanthrenyl, preferably phenyl, which is unsubstituted or substituted with one or more of the following groups:

[0046] C1-C 12 Alkyl groups such as 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 C1-C6 alkyl groups such as 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, particularly preferably C1-C4 alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isohexyl, sec-butyl and tert-butyl.

[0047] Halogen, such as fluorine, chlorine, bromine, iodine, preferably chlorine.

[0048] C1-C 12 Alkoxy, preferably C1-C6 alkoxy, such as methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, n-pentoxy, isopentylpropoxy, n-hexyloxy and isohexyloxy, particularly preferably methoxy, ethoxy, n-propoxy, n-butoxy.

[0049] Preferably, the first carbonyl compound contains α-H, and the second carbonyl compound contains α-H or does not contain α-H.

[0050] Further preferably, the carbonyl compound not containing α-H is preferably formaldehyde, benzaldehyde, furfural, 5-hydroxyfurfural, 5-methylfurfural or a derivative thereof, and formaldehyde is further preferred; the carbonyl compound containing α-H is preferably acetaldehyde, propionaldehyde, acetone, butyraldehyde, butanone, valeraldehyde, pentanone, hexanal, hexanone, cyclohexanone, cyclopentanone, acetic acid, propionic acid, malonic acid, butyric acid, succinic acid, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, cyclohexyl acetate, methyl propionate, ethyl propionate, butyl propionate, dimethyl malonate, methyl butyrate, dimethyl succinate, ethyl butyrate or at least one of their derivatives.

[0051] In the aldol condensation method, the molar ratio of the first carbonyl compound to the second carbonyl compound is 1:(0.1-10), further preferably 1:(0.2-6), more preferably 1:(0.4-4), more preferably 1:(0.8-3), and most preferably 1:(1-2).

[0052] In the aldol condensation method, the carbonyl compound mixed stream further comprises one or more diluents, the diluents comprising at least one of alcohols, ethers, alkanes, halogenated alkanes, and toluene, preferably methanol, cycloalkanes, diethyl ether, and toluene. The molar ratio of the diluent to the carbonyl compound is (30-0.5):1, preferably (20-0.7):1, further preferably (10-0.8):1, more preferably (5-0.9):1, and most preferably (3-1):1.

[0053] In the aldol condensation method, the aldol condensation reaction is preferably carried out in an atmosphere containing at least one gas selected from the group consisting of N2, He, Ar, CH4, C2H6, H2, CO, and CO2, and more preferably in an atmosphere containing N2.

[0054] In the aldol condensation method, the aldol condensation reaction temperature is 300-500°C, preferably 320-400°C, and more preferably 340-380°C. Prior to the reaction, the temperature of the mixed solution is preferably raised to 300-400°C, more preferably 340-400°C. The reaction pressure is 0-5 MPa, preferably 0-1.5 MPa, and more preferably 0-1.0 MPa, as a gauge pressure.

[0055] In the aldol condensation method, the hourly space velocity of the reaction liquid is 0.05-5h, based on the total mass of the carbonyl compound and the diluent. -1 , preferably 0.08-3h -1 , more preferably 0.1-2.5h -1 .

[0056] The process according to the present invention, wherein the formaldehyde source is an anhydrous formaldehyde source, preferably methylal, trioxymethylene and paraformaldehyde, has been found by the inventors to be capable of surprisingly improved activity and selectivity for the condensation of a methylene source such as formaldehyde with a carboxylic acid or a hydrocarbyl ester such as methyl acetate to form an ethylenically unsaturated carboxylic acid.

[0057] In the aldol condensation method, an optional specific embodiment is that formaldehyde and methyl acetate undergo an aldol condensation reaction, and the conditions include: a methyl acetate: formaldehyde molar ratio of 5:2 to 1:1, a methanol: methyl acetate molar ratio of 1:1 to 2:1, a reaction temperature of 340 to 380°C, a reaction pressure (gauge pressure) of 0 to 1.0 MPa, a nitrogen flow rate of 30 to 100 mL / min, and a reaction liquid hourly space velocity of 0.1 to 2.5 h -1 The space velocity should be understood as the mass space velocity, which means the ratio of the mass flow rate of the total mass of the reactant substrate and the diluent (unit is (mass / time)) to the mass of the catalyst. Therefore, the unit of space velocity is h -1 .

[0058] In the aldol condensation method, another optional specific embodiment is that formaldehyde and methyl propionate undergo an aldol condensation reaction, and the conditions include: a methyl propionate: formaldehyde molar ratio of 1:2 to 1:0.2, a methanol: methyl propionate molar ratio of 1:1 to 5:1, a reaction temperature of 320 to 400°C, a reaction pressure (gauge pressure) of 0 to 1 MPa, a nitrogen flow rate of 30 to 100 mL / min, and a reaction liquid hourly space velocity of 0.1 to 2 h -1 .

[0059] The method for the aldol condensation is preferably carried out in a fixed-bed reactor, a fluidized-bed reactor or an autoclave reactor. It will be appreciated by those skilled in the art that, depending on the difference in the reactor used, the catalyst of the present invention can be the original powder of the catalyst modified by the basic metal element, or the shaped catalyst after the shaping of the basic metal element modification, and the weight proportion of the aldol condensation reaction catalyst in the catalyst can be 5%-100%. The separation of the product and the catalyst can be achieved in a variety of ways. For example, when the catalyst modified by the original powdered basic metal element is the catalyst, the separation of the product and the recycling of the catalyst can be achieved by sedimentation, filtration, centrifugation, evaporation, membrane separation or the like. Alternatively, the catalyst can be shaped and loaded into a fixed-bed reactor, and the catalyst can be recovered after the reaction is completed. The separation and recovery methods of various catalysts are widely described in the existing literature and will not be elaborated herein.

[0060] The present invention is described in detail below through examples.

[0061] N2 adsorption and desorption characterization and analysis: Autosorb 6B static nitrogen adsorption instrument, produced by Quantachrome.

[0062] Test conditions: After the sample is loaded, the temperature is raised to 300°C and the vacuum is evacuated to 1.33×10 -2 Pa, constant temperature and pressure for 4 hours to purify the sample. Then characterize it at -196℃ in liquid nitrogen. The specific surface area is calculated by BET formula, and the pore volume of the sample is calculated by p / p 0 The adsorption capacity was calculated under the condition of ≤0.98, and the pore size distribution was calculated by the BJH formula.

[0063] X-ray fluorescence spectrometer (XRF): ZSX100E X-ray fluorescence spectrometer, produced by Rigaku Co., Ltd., Japan.

[0064] Test conditions: The sample was pressed into a pellet, using tungsten-palladium, an excitation voltage of 40 kV, and an excitation current of 250 mA.

[0065] X-ray powder diffraction (XRD): Empyrean X-ray diffractometer, produced by Philips.

[0066] Test conditions: CuKα radiation, λ = 0.15406 nm, 2θ scanning range of 5°-35°.

[0067] The catalytic performance test was conducted in a fixed-bed reactor at atmospheric pressure. The prepared catalyst was used to catalyze the aldol condensation of methyl acetate and formaldehyde to synthesize methyl acrylate. The molar ratio of methyl acetate to formaldehyde was 1:1, methanol was used as the solvent, the molar ratio of methyl acetate to methanol was 1:2, and the feed space velocity of the raw material mixture was 1h. -1The catalyst dosage was 5 g. The carrier gas (N2) flow rate was maintained at 50 mL / min and the reaction temperature was 360°C. The product was condensed and analyzed by chromatography.

[0068] Unless otherwise specified, the raw materials in the examples of this application were purchased from commercial channels and were pure reagents.

[0069] The analysis methods in the examples and comparative examples of the present application are as follows:

[0070] The reaction product was analyzed for composition by gas chromatography, and the results were quantified using an external standard method. The following analysis conditions were used: an Agilent 6890 chromatograph, an HP5 capillary column, an injection volume of 0.5 μL, and an injection port temperature of 280°C. The column temperature was maintained at 100°C for 2 minutes, then increased to 200°C at a rate of 15°C / min and held there for 3 minutes. The FID detector was set at 300°C.

[0071] The calculations of conversion, selectivity and yield in the examples are as follows:

[0072]

[0073] Y 丙烯酸甲酯 =C 醋酸甲酯 ×S 丙烯酸甲酯

[0074] Comparative Example 1

[0075] Tetraethyl silicate (TEOS) and hydrochloric acid solution (pH 3) were mixed in a molar ratio of 1:30, hydrolyzed at 40°C for 6 hours, and the resulting solid was separated by filtration. The solid was dried at 120°C for 6 hours and then calcined at 500°C for 3 hours to obtain amorphous silica as a support.

[0076] Silica, cesium carbonate, and water were mixed in a silicon-to-cesium molar ratio of 1:0.03 and a silicon-to-solvent molar ratio of 1:40. The mixture was stirred at 40°C for 30 minutes at atmospheric pressure, and the solvent was then evaporated to obtain a solid. This solid was dried at 120°C for 6 hours and then calcined at 400°C for 6 hours to obtain Cs / SiO2. The catalyst was characterized and evaluated, and the results are shown in Table 1. The results of the aldol condensation reaction are shown in Table 2.

[0077] Comparative Example 2

[0078] SBA-15 molecular sieve, cesium carbonate and water were mixed, with the molar ratio of silicon to cesium being 1:0.03 and the molar ratio of silicon to solvent being 1:40. The mixture was stirred at normal pressure and 40°C for 30 min, and then the solvent was evaporated to obtain a solid. The solid was dried at 120°C for 6 h, and then calcined at 400°C for 6 h to obtain Cs / SBA-15. The catalyst was characterized and evaluated, and the results are shown in Table 1. The pore distribution graph of the sample of Comparative Example 2 is shown in Figure 2 There was an obvious pore distribution in the range of 6-8 nm. The evaluation results of the aldol condensation reaction are shown in Table 2.

[0079] Example 1

[0080] Tetraethyl silicate (TEOS) and a hydrochloric acid solution with a pH of 3 were mixed in a molar ratio of 1:30, and hydrolysis was carried out at 40°C for 6 h. The obtained solid was separated by filtration. The solid was dried at 120°C for 6 h, and then calcined at 500°C for 3 h to obtain the carrier amorphous silica.

[0081] Silica, cesium carbonate and water were mixed, with the molar ratio of silicon to cesium being 1:0.03 and the molar ratio of silicon to solvent being 1:2. The mixture was stirred at normal pressure and 40°C for 30 min, and then the solvent was evaporated to obtain a solid. The solid was treated with water vapor at 120°C and normal pressure for 3 h, and then dried at 120°C for 6 h. The solid was calcined at 400°C for 6 h to obtain Cs / SiO2. The catalyst was characterized and evaluated, and the results are shown in Table 1. The XRD spectrum of the sample of Example 1 is shown in Figure 1 The XRD spectrum shows that there is a large broad peak at 24°, which is a characteristic peak of amorphous silica. After modification with an alkali metal, no impurity peak appears, indicating that the alkali metal is uniformly distributed in the silica. The pore distribution graph is shown in Figure 2 As can be seen from Figure 2 , the modified silica has an obvious pore distribution in the range of 16-32 nm. The evaluation results of the aldol condensation reaction are shown in Table 2.

[0082] Example 2

[0083] Tetraethyl silicate (TEOS) and a hydrochloric acid solution with a pH of 3 were mixed in a molar ratio of 1:30, and hydrolysis was carried out at 60°C for 6 h. The obtained solid was separated by filtration. The solid was dried at 100°C for 6 h, and then calcined at 550°C for 6 h to obtain the carrier amorphous silica.

[0084] Silica, cesium nitrate, and water were mixed in a silicon-to-cesium molar ratio of 1:0.04 and a silicon-to-solvent molar ratio of 1:4. The mixture was stirred at 1 MPa (gauge pressure) and 60°C for 60 minutes, and the solvent was then evaporated to obtain a solid. This solid was steamed at 180°C and atmospheric pressure for 2 hours, dried at 100°C for 3 hours, and then calcined at 500°C for 3 hours to obtain Cs / SiO2. The catalyst was characterized and evaluated, and the results are shown in Table 1. The results of the aldol condensation reaction are shown in Table 2.

[0085] Example 3

[0086] Tetraethyl silicate (TEOS) and hydrochloric acid solution with a pH of 3 were mixed in a molar ratio of 1:30, hydrolyzed at 40°C for 6 hours, and the resulting solid was separated by filtration. The solid was dried at 120°C for 6 hours to obtain a support amorphous silica.

[0087] Silica, cesium nitrate, and water were mixed in a silicon-to-cesium molar ratio of 1:0.03 and a silicon-to-solvent molar ratio of 1:2. The mixture was ground at 0.5 MPa (gauge pressure) and 40°C for 30 minutes to obtain a solid. This solid was steamed at 120°C and 0.2 MPa (gauge pressure) for 3 hours, dried at 120°C for 6 hours, and then calcined at 400°C for 3 hours to obtain Cs / SiO2. The catalyst was characterized and evaluated, and the results are shown in Table 1. The results of the aldol condensation reaction are shown in Table 2.

[0088] Example 4

[0089] Tetraethyl silicate (TEOS) and ammonia solution with a pH of 11 were mixed in a molar ratio of 1:30, hydrolyzed at 40°C for 12 hours, and the resulting solid was separated by filtration. The solid was dried at 120°C for 3 hours to obtain a support amorphous silica.

[0090] Silica, cesium carbonate, and water were mixed in a silicon-to-cesium molar ratio of 1:0.02 and a silicon-to-solvent molar ratio of 1:4. The mixture was ground at 0.3 MPa (gauge pressure) and 50°C for 15 minutes to obtain a solid. This solid was steamed at 180°C and 0.8 MPa (gauge pressure) for 5 hours, dried at 130°C for 2 hours, and then calcined at 450°C for 8 hours to obtain Cs / SiO2. The catalyst was characterized and evaluated, and the results are shown in Table 1. The results of the aldol condensation reaction are shown in Table 2.

[0091] Example 5

[0092] Tetraethyl silicate (TEOS) and hydrochloric acid solution with a pH of 3 were mixed in a molar ratio of 1:30, hydrolyzed at 60°C for 6 hours, and the resulting solid was separated by filtration. The solid was dried at 100°C for 6 hours to obtain a support amorphous silica.

[0093] Silica, cesium nitrate, and ethanol were mixed in a silicon-to-cesium molar ratio of 1:0.04 and a silicon-to-solvent molar ratio of 1:2. The mixture was ground at 0.5 MPa (gauge pressure) and 60°C for 30 minutes to obtain a solid. This solid was steamed at 170°C and 0.8 MPa (gauge pressure) for 8 hours, dried at 120°C for 3 hours, and then calcined at 400°C for 5 hours to obtain Cs / SiO2. The catalyst was characterized and evaluated, and the results are shown in Table 1. The results of the aldol condensation reaction are shown in Table 2.

[0094] Example 6

[0095] Tetraethyl silicate (TEOS) and hydrochloric acid solution with a pH of 3 were mixed in a molar ratio of 1:30, hydrolyzed at 40°C for 6 hours, and the resulting solid was separated by filtration. The solid was dried at 120°C for 3 hours to obtain a support amorphous silica.

[0096] Silica, cesium hydroxide, and water were mixed in a silicon-to-cesium molar ratio of 1:0.03 and a silicon-to-solvent molar ratio of 1:2. The mixture was ground at 0.7 MPa (gauge pressure) and 70°C for 15 minutes to obtain a solid. This solid was steamed at 120°C and 0.25 MPa (gauge pressure) for 4 hours, dried at 110°C for 5 hours, and then calcined at 500°C for 8 hours to obtain Cs / SiO2. The catalyst was characterized and evaluated, and the results are shown in Table 1. The results of the aldol condensation reaction are shown in Table 2.

[0097] Example 7

[0098] The specific surface area is 200m 2 / g of hydrophilic silica is mixed with cesium nitrate and water, wherein the molar ratio of silicon to cesium is 1:0.03, and the molar ratio of silicon to solvent is 1:2. The mixture is ground at -0.3MPa pressure (gauge pressure) and 40°C for 15min to obtain a solid. The solid is steam treated at 130°C and 0.3MPa pressure (gauge pressure) for 3h, further dried at 120°C for 6h, and then calcined at 400°C for 6h to obtain Cs / SiO2. The catalyst is characterized and evaluated, and the results are shown in Table 1. The XRD spectrum of the sample in Example 7 is shown in Figure 1 The XRD spectrum shows a large broad peak at 24°, which is a characteristic peak of amorphous silica. After alkali metal modification, no impurity peaks appear, indicating that the alkali metal is evenly distributed in the silica. See the pore distribution diagram Figure 2 ,from Figure 2 It can be seen that the modified silica has a clear pore distribution in the range of 32-50 nm. The evaluation results of the aldol condensation reaction are shown in Table 2.

[0099] Example 8

[0100] The specific surface area is 200m 2 / g of hydrophilic silica was mixed with cesium hydroxide and water, with a silicon to cesium molar ratio of 1:0.05 and a silicon to solvent molar ratio of 1:1. The mixture was ground at -0.5 MPa (gauge pressure) and 70°C for 30 minutes to obtain a solid. This solid was steamed at 160°C and 0.6 MPa (gauge pressure) for 5 hours, further dried at 130°C for 5 hours, and then calcined at 400°C for 3 hours to obtain Cs / SiO2. The catalyst was characterized and evaluated, and the results are shown in Table 1. The results of the aldol condensation reaction are shown in Table 2.

[0101] Example 9

[0102] The specific surface area is 400m 2 / g of hydrophilic silica was mixed with cesium carbonate and water, with a silicon-to-cesium molar ratio of 1:0.03 and a silicon-to-solvent molar ratio of 1:4. The mixture was ground at -0.4 MPa (gauge pressure) and 50°C for 60 minutes to obtain a solid. This solid was steamed at 150°C and 0.47 MPa (gauge pressure) for 8 hours, dried at 110°C for 3 hours, and then calcined at 450°C for 5 hours to obtain Cs / SiO2. The catalyst was characterized and evaluated, and the results are shown in Table 1.

[0103] The evaluation results of the aldol condensation reaction are shown in Table 2.

[0104] Example 10

[0105] The specific surface area is 400m 2 / g of hydrophilic silica was mixed with cesium nitrate and ethanol, with a silicon to cesium molar ratio of 1:0.04 and a silicon to solvent molar ratio of 1:3. The mixture was ground at -0.3 MPa (gauge pressure) and 60°C for 30 minutes to obtain a solid. This solid was steamed at 140°C and 0.36 MPa (gauge pressure) for 4 hours, dried at 120°C for 5 hours, and then calcined at 500°C for 6 hours to obtain Cs / SiO2. The catalyst was characterized and evaluated, and the results are shown in Table 1. The results of the aldol condensation reaction are shown in Table 2.

[0106] Table 1

[0107]

[0108] Table 2

[0109] Example Methyl acetate conversion rate / % Methyl acrylate selectivity / % Methyl acrylate yield / % Comparative Example 1 32 72 23 Comparative Example 2 37 74 27 Example 1 78 88 69 Example 2 79 88 70 Example 3 79 90 71 Example 4 80 89 71 Example 5 81 89 72 Example 6 81 90 73 Example 7 84 92 77 Example 8 85 92 78 Example 9 83 91 76 Example 10 83 91 76

[0110] As can be seen from the comparative data of Examples 1-10 and Comparative Examples 1-2 in Table 2, the aldol condensation reaction catalysts of the present invention have unique physicochemical properties and can significantly improve feedstock conversion and product yield. The byproducts of the present invention are primarily isobutyraldehyde, methacrolein, and methyl methacrylate, while the byproducts of the comparative examples include acetone, acetic acid, and the like.

[0111] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An aldol condensation reaction catalyst, characterized in that Contains silicon, oxygen and alkali metal elements, has an amorphous structure, and the micropore volume is less than 0.05cm 3 / g, and the mesopore volume is greater than 0.55cm 3 / g, with obvious pore distribution in the range of 16-50nm and a specific surface area of ​​50-300m 2 / g, the ratio of mesopore volume to total pore volume is (0.9-0.99):1, the catalyst is characterized by NMR silicon spectrum, the ratio of -113ppm signal peak height to -103ppm signal peak height Q 4 / Q 3 >100, where Q 4 represents Si(OSi)4 species, Q 3 Represents Si(OSi)3(OH) species; the catalyst is prepared by mixing silicon dioxide with an alkali metal hydroxide or alkali metal salt and a solvent, stirring or grinding the mixture to uniform consistency, then treating the mixture under steam conditions, and finally drying and calcining the treated solid. The steam treatment is carried out at 100-200°C water vapor and a gauge pressure of 0-1 MPa for 0.1-24 hours.

2. The catalyst according to claim 1, characterized in that The pore volume of micropores is less than 0.03 cm 3 / g, and the mesopore volume is greater than 0.60 cm 3 / g.

3. The catalyst according to claim 2, characterized in that The pore volume of micropores is less than 0.02 cm 3 / g, and the mesopore volume is greater than 0.70 cm 3 / g.

4. The catalyst according to claim 1, characterized in that The Q 4 / Q 3 >150.

5. The catalyst according to claim 1, characterized in that The Q 4 / Q 3 >200.

6. The catalyst according to claim 1, characterized in that The Q 4 / Q 3 >250.

7. The catalyst according to claim 1, characterized in that The Q 4 / Q 3 >300.

8. The catalyst according to claim 1, characterized in that The catalyst was characterized by silica NMR spectrum, which showed no -103 ppm signal peak.

9. The catalyst according to claim 1, characterized in that The alkali metal element is selected from one or more of lithium, sodium, potassium, rubidium and cesium.

10. The catalyst according to claim 1, characterized in that The alkali metal element is selected from one or more of potassium, rubidium and cesium.

11. The catalyst according to claim 1, characterized in that The alkali metal element is selected from one or both of rubidium and cesium.

12. The catalyst according to claim 1, characterized in that The alkali metal element is cesium.

13. The catalyst according to claim 1, characterized in that The molar ratio of the alkali metal element to the silicon element is (0.001-0.1):

1.

14. The catalyst according to claim 13, characterized in that The molar ratio of the alkali metal element to the silicon element is (0.005-0.08):

1.

15. The catalyst according to claim 14, characterized in that The molar ratio of the alkali metal element to the silicon element is (0.01-0.06):

1.

16. The catalyst according to claim 15, characterized in that The molar ratio of the alkali metal element to the silicon element is (0.02-0.05):

1.

17. The catalyst according to claim 1, characterized in that The ratio of the matrix specific surface area to the micropore specific surface area is (1-7):1, matrix specific surface area=BET specific surface area-micropore specific surface area.

18. The catalyst according to claim 17, characterized in that The ratio of the matrix specific surface area to the micropore specific surface area is (2-6):

1.

19. The catalyst according to claim 18, characterized in that The ratio of the matrix specific surface area to the micropore specific surface area is (3-5):

1.

20. A method for preparing the aldol condensation reaction catalyst according to claim 1, characterized in that: Silicon dioxide is mixed with an alkali metal hydroxide or salt and a solvent, stirred or ground to mix evenly, and then treated under steam conditions. Finally, the treated solid is dried and calcined. The steam treatment conditions are water vapor at 100-200° C. and a gauge pressure of 0-1 MPa for 0.1-24 hours.

21. The preparation method according to claim 20, characterized in that The treatment under the steam conditions is to treat at 120-180° C. water vapor and a gauge pressure of 0.1-0.8 MPa for 1-12 hours.

22. The preparation method according to claim 21, characterized in that The treatment under the steam conditions is to treat at 130-160° C. water vapor and a gauge pressure of 0.3-0.6 MPa for 2-8 hours.

23. The preparation method according to claim 20, characterized in that The silicon dioxide is selected from white carbon black or silicon dioxide produced by hydrolysis and precipitation of organic silicone ester.

24. The preparation method according to claim 23, characterized in that The white carbon black has a SiO2 weight content greater than 99% and a specific surface area of ​​50-1000m 2 / g.

25. The preparation method according to claim 24, characterized in that The white carbon black has a SiO2 weight content greater than 99.9%.

26. The preparation method according to claim 24, characterized in that The white carbon black has a specific surface area of ​​100-800m 2 / g.

27. The preparation method according to claim 26, characterized in that The white carbon black has a specific surface area of ​​150-500m 2 / g.

28. The preparation method according to claim 23, characterized in that The white carbon black is hydrophilic white carbon black.

29. The preparation method according to claim 23, characterized in that The organic silicon ester is tetraalkoxy silicon, which has the structure of R1, R2, R3, R4 (SiO4), wherein R1, R2, R3, R4 are independently C1-C 12 The alkyl, alkenyl, alkynyl, or aryl substituent groups are each R group connected to an oxygen atom of silicon.

30. The preparation method according to claim 29, characterized in that The tetraalkoxysilicon is tetraethoxysilicon and / or tetrapropoxysilicon.

31. The preparation method according to claim 20, characterized in that The alkali metal salt is selected from the group consisting of alkali metal hydrochlorides, hypochlorites, chlorites, metachlorites, perchlorates, nitrates, sulfates, bisulfates, sulfites, bisulfites, phosphates, hydrogenphosphates, dihydrogenphosphates, high phosphates, metaphosphates, phosphites, hypophosphites, carboxylates, pyrophosphates, C1-C 20 One or more carboxylates.

32. The preparation method according to claim 20, characterized in that The alkali metal salt is cesium nitrate, cesium carbonate, cesium bicarbonate, or cesium acetate, and the alkali metal hydroxide is cesium hydroxide.

33. The preparation method according to claim 20, characterized in that The molar ratio of silicon dioxide to solvent is 1:(0-10), wherein silicon dioxide is calculated as SiO2.

34. The preparation method according to claim 33, characterized in that The molar ratio of the silicon dioxide to the solvent is 1:(0.5-7).

35. The preparation method according to claim 34, characterized in that The molar ratio of the silicon dioxide to the solvent is 1:(1-4).

36. The preparation method according to claim 20, characterized in that The solvent is at least one of water, methanol, ethanol and propanol.

37. The preparation method according to claim 20, characterized in that The stirring or grinding is carried out for 5-120 minutes at a gauge pressure of -0.1 MPa to -0.5 MPa and a temperature of 20-150°C.

38. An aldol condensation reaction catalyst obtained according to the preparation method of any one of claims 20 to 37.

39. An aldol condensation reaction method, characterized in that: In the presence of the catalyst of any one of claims 1 to 19 or the catalyst of claim 38, a first carbonyl-containing compound having α-H and a second carbonyl-containing compound undergo a carbon-carbon bond coupling reaction to generate a carbonyl-containing compound having a β-hydroxyl group or a carbonyl-containing compound having an α,β-unsaturated bond.

40. The reaction method according to claim 39, characterized in that The first carbonyl compound contains α-H, and the second carbonyl compound contains α-H or does not contain α-H.

41. The reaction method according to claim 40, characterized in that 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): wherein R1 to R2 are 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; 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; R3, R7 to 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; 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; The unsubstituted cycloalkyl group is selected from one or more of cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, cycloundecyl and cyclododecyl; wherein The substituents on the substituted cycloalkyl group are selected from alkyl groups having 1 to 9 carbon atoms; 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; 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; The substituent on the substituted furyl 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.

42. The reaction method according to claim 41, characterized in that The halogen group is selected from one or more of fluorine, chlorine, bromine and iodine.

43. The reaction method according to claim 41, characterized in that The halogen group is chlorine.

44. The reaction method according to claim 41, characterized in that The alkyl group having 1 to 12 carbon atoms is a methyl group; the substituent on the substituted cycloalkyl group is one or more selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl and tert-butyl; the substituted or unsubstituted cycloalkyl group having 3 to 12 carbon atoms is one or more selected from the group consisting of cyclopentyl, cyclohexyl and cycloheptyl; the substituent on the substituted aryl group is one or more selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl and tert-butyl; the substituted or unsubstituted aryl group having 6 to 14 carbon atoms is one or more selected from the group consisting of phenyl, benzyl, propylphenyl and butylphenyl; the alkoxy group having 1 to 12 carbon atoms is one or more selected from the group consisting of methoxy, ethoxy, n-propoxy and n-butoxy.

45. The reaction method according to claim 41, characterized in that The substituted or unsubstituted aryl group having 6 to 14 carbon atoms is a phenyl group.

46. ​​The reaction method according to claim 39, 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; the second carbonyl compound is selected from one or more of cyclohexanone, cyclopentanone, methyl acetate, ethyl acetate, methyl propionate, methyl butyrate, 2,2-dimethyl methyl propionate, 2,2-dimethylpropionaldehyde, formaldehyde, benzaldehyde, furfural, 5-hydroxyfurfural and 5-methylfurfural.

47. The reaction method according to claim 39, characterized in that The first carbonyl compound is methyl propionate, and the second carbonyl compound is formaldehyde.

48. The reaction method according to claim 39, characterized in that The molar ratio of the second carbonyl compound to the first carbonyl compound is 1:(0.1-10).

49. The reaction method according to claim 39, characterized in that The molar ratio of the second carbonyl compound to the first carbonyl compound is 1:(0.2-6).

50. The reaction method according to claim 39, characterized in that The molar ratio of the second carbonyl compound to the first carbonyl compound is 1:(0.4-4).

51. The reaction method according to claim 39, characterized in that The molar ratio of the second carbonyl compound to the first carbonyl compound is 1:(0.8-3).

52. The reaction method according to claim 39, characterized in that The molar ratio of the second carbonyl compound to the first carbonyl compound is 1:(1-2).

53. The reaction method according to claim 39, characterized in that The carbonyl compound mixed stream further comprises one or more diluents, wherein the diluents include at least one of alcohols, ethers, alkanes, halogenated alkanes, and toluene; and the molar ratio of the diluent to the carbonyl compound is (30-0.5):

1.

54. The reaction method according to claim 53, characterized in that The diluent is methanol, cycloalkane, ether or toluene.

55. The reaction method according to claim 53, characterized in that The molar ratio of the diluent to the carbonyl compound is (20-0.7):

1.

56. The reaction method according to claim 55, characterized in that The molar ratio of the diluent to the carbonyl compound is (10-0.8):

1.

57. The reaction method according to claim 56, characterized in that The molar ratio of the diluent to the carbonyl compound is (5-0.9):

1.

58. The reaction method according to claim 57, characterized in that The molar ratio of the diluent to the carbonyl compound is (3-1):

1.

59. The reaction method according to claim 39, characterized in that The aldol condensation reaction between formaldehyde and methyl acetate occurs under the following conditions: The process comprises: a methyl acetate: formaldehyde molar ratio of 5:2 to 1:1, a methanol: methyl acetate molar ratio of 1:1 to 2:1, a reaction temperature of 340 to 380°C, a reaction gauge pressure of 0 to 1.0 MPa, a nitrogen flow rate of 30 to 100 mL / min, and a reaction liquid hourly space velocity of 0.1 to 2.5 h -1 .

60. The reaction method according to claim 39, characterized in that The aldol condensation reaction of formaldehyde and methyl propionate is carried out under the following conditions: a molar ratio of methyl propionate to formaldehyde of 1:2 to 1:0.2, a molar ratio of methanol to methyl propionate of 1:1 to 5:1, a reaction temperature of 320 to 400°C, a gauge pressure of 0 to 1 MPa, a nitrogen flow rate of 30 to 100 mL / min, and a liquid hourly space velocity of 0.1 to 2 h -1 .

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