Alkali metal modified titanium silicalite molecular sieve as well as preparation method and application thereof

Abstract

An alkali metal modified titanium silicalite molecular sieve is characterized in that the molecular sieve contains titanium, silicon, oxygen and alkali metal elements, a Raman spectrum of a 325nm light source is used for characterizing that a titanium species signal peak exists in a range of 990cm <-1 > + / -20cm <-1 >, no obvious titanium species signal peak exists in a range of 1125cm <-1 > + / -20cm <-1 >, a molecular sieve skeleton structure signal peak exists in a range of 800cm <-1 > + / -20cm <-1 >, and the peak area is calculated as intensity. And the ratio I (90) / I (800) of the signal peak intensity of 990 + / -20 cm <-1 > to the signal peak intensity of 800 + / -20 cm <-1 > is (0.2-2): 1.

Description

Technical Field

[0001] The present invention belongs to the technical field of molecular sieve catalysts, and more specifically relates to titanium silicon molecular sieve, a method for modifying the molecular sieve and an application in aldol condensation reaction. Background Art

[0002] Methyl acrylate is an important organic intermediate and is widely used in industries such as rubber, leather, medicine and coatings. At present, there are several main methods for producing methyl acrylate: propylene oxidation, acrylonitrile hydrolysis and propane oxidation. Industrial production is mainly based on propylene oxidation, which has technical and economic advantages but low efficiency. The acrylonitrile hydrolysis method has a small output and sulfuric acid cannot be recycled. The propane oxidation method is a commonly used method, although it is cheap, but the product yield is low. The preparation of methyl acrylate by condensation reaction of coal-based methyl acetate (or acetic acid) and formaldehyde is a very important and highly productive process synthesis route. This synthesis route not only has low production costs, but also effectively controls the discharge of polluted waste liquid, and has great application prospects. Research and development of catalysts with high catalytic activity is the key to realizing the industrialization of this process.

[0003] The literature reports the research progress of acetic acid (ester)-formaldehyde condensation to produce acrylic acid (ester) (Chemical Industry Progress, 2021, 40 (4): 2005-2015). The catalysts currently used for this route include VPO catalysts, alkali metal / alkaline earth metal catalysts and ionic liquid catalysts. 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 liquids 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.

[0004] CN108097290A reports a catalyst for preparing acrylic acid / methyl acrylate from raw materials containing carbon monoxide and formaldehyde compounds. The catalyst is mainly obtained by metal modification of commercially available MOR molecular sieves with different silicon-aluminum ratios using at least one selected from copper, silver, iron, cobalt, nickel and gallium through impregnation, ion exchange and in-situ synthesis. The catalyst has a maximum selectivity of 88.2% for acrylic acid and 5.3% for methyl acrylate.

[0005] CN106693941A reports a catalyst with Li, Na, K, Rb, Cs, Mg, Ca, Sr, and Ba as active components and Al2O3 as a carrier prepared by a coprecipitation method. Under the condition that the molar ratio of methyl acetate: formaldehyde: methanol is 1:2:2, the conversion rate of methyl acetate is 34.4% and the selectivity of methyl acrylate is 93.4%.

[0006] CN104258901A 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 applied to the reaction of preparing methyl acrylate by aldol condensation of methyl acetate and formaldehyde. Under the condition that 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%.

[0007] Teng He et al. reported in Catalysis Letters, 2019, 149(2):373-389 that cesium-loaded SiO2 was used as a catalyst 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. Under the conditions of a reaction temperature of 390°C, the conversion rate of methyl acetate was about 35%, and the selectivity of methyl acrylate was 85-90%.

[0008] Studies have shown that among various catalysts for catalyzing the aldol condensation reaction of methyl acetate and formaldehyde, the performance of silica-supported Cs alkali metal catalyst is the best, but the catalytic activity is not ideal. Summary of the invention

[0009] One of the purposes of the present invention is to provide a modified titanium silicon molecular sieve and a preparation method thereof which are different from the prior art. The second purpose of the present invention is to provide a catalyst with the modified titanium silicon molecular sieve as an active component. The third purpose of the present invention is to provide a method for aldol condensation reaction.

[0010] In order to achieve one of the above objects, the present invention provides an alkali metal modified titanium silicon molecular sieve, characterized in that the molecular sieve contains titanium, silicon, oxygen and alkali metal elements, characterized by Raman spectrum of 325nm light source at 990±20cm -1 There is a titanium species signal peak in the range of 1125±20cm -1 There is no obvious titanium species signal peak in this range.

[0011] In order to achieve one of the purposes of the present invention, the present invention also provides a method for preparing the alkali metal-modified titanium silicon molecular sieve of the present invention, characterized in that the titanium silicon molecular sieve as a modified raw material is mixed with an alkali metal hydroxide or an alkali metal salt and water and / or an organic solvent, and then the water and / or the organic solvent are removed, and then the alkali metal-containing titanium silicon molecular sieve is obtained through drying and calcination, wherein the mixing treatment is carried out at 50-100°C, the gauge pressure is 0.1-5MPa, and the treatment time is 0.5-12h.

[0012] In order to achieve the second purpose of the present invention, the present invention provides a titanium silicalite molecular sieve catalyst, characterized in that it contains the alkali metal modified titanium silicalite provided by the above-mentioned present invention or the alkali metal modified titanium silicalite prepared by the preparation method provided by the above-mentioned present invention, and the weight ratio of the alkali metal modified titanium silicalite to the titanium silicalite molecular sieve catalyst is preferably 5%-100%.

[0013] In order to achieve the third purpose of the present invention, the present invention also provides an application of a titanium silicalite catalyst, wherein the application is that in the method for preparing a carbonyl compound containing a titanium silicalite catalyst of the present invention, a carbonyl compound containing α-H undergoes a carbon-carbon bond coupling reaction with another carbonyl compound in the presence of the titanium silicalite catalyst of the present invention to generate a carbonyl compound containing β-hydroxyl or a carbonyl compound containing α,β-unsaturated bonds.

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

[0015] (1) The titanium in the titanium silicalite is modified by alkali metal modification under specific conditions to produce a new active center species, which has Raman spectral characterization characteristics and IR characterization characteristics different from the existing technology; the active center species has good catalytic performance and can provide good product selectivity while improving catalytic activity.

[0016] (2) The alkali metal modification method is simple, short in steps, and has a wide source of raw materials, making it suitable for large-scale industrial applications and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 IR spectra of Example 1 and Comparative Example 1;

[0018] Figure 2 The UV-Raman spectra of Example 1 and Comparative Example 1 are shown. DETAILED DESCRIPTION

[0019] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0020] The alkali metal-modified titanium silicon molecular sieve provided by the present invention is characterized in that the molecular sieve contains titanium, silicon, oxygen and alkali metal elements, and is characterized by Raman spectrum of 325nm light source at 990±20cm -1 There is a titanium species signal peak in the range of 1125±20cm -1 There is no obvious titanium species signal peak in this range.

[0021] The laser Raman spectrum of the 325nm light source can effectively excite the resonance of titanium species and provide a strong signal intensity of titanium species. The alkali metal-modified titanium silicon molecular sieve provided by the present invention is characterized by the Raman spectrum of the 325nm light source. It can be found that at 990±20cm -1 There are identifiable titanium species signal peaks in the range of 990 ± 10 cm -1 , more preferably 990±5cm -1 ;990±20cm -1 The definition of the identifiable titanium species signal peak within the range is: 990±20cm -1 Signal peak intensity and 800±20cm -1 The signal peak intensity ratio I(990) / I(800) is (0.2-2):1, preferably (0.5-1.6):1, and more preferably (0.8-1.3):1. At 1125±20cm -1 There is no obvious titanium species signal peak in the range. -1 The range without obvious titanium species signal peak is defined as: calculated by peak area as intensity, 1125±20cm -1 Signal peak intensity and 800±20cm -1 The signal peak intensity ratio I(1125) / I(800) is less than 0.1, more preferably less than 0.05. More preferably, the alkali metal-modified titanium silicalite provided by the present invention has no 1125cm -1 A signal peak appears.

[0022] When the alkali metal-modified titanium silicalite provided by the present invention is characterized by Raman with a 325 nm light source, it can be found that at 800 ± 20 cm -1 There is a molecular sieve framework structure signal peak in the range, and the peak area is used as the intensity calculation, 990±20cm -1 Signal peak intensity and 800±20cm -1 The signal peak intensity ratio I(990) / I(800) is (0.2-2):1, preferably (0.5-1.6):1, and more preferably (0.8-1.3):1.

[0023] literature( Phys.Chem.Chem.Phys. ,2016,18,190-196) Studies have shown that, in general, in Raman spectroscopy, 960±10cm -1 and 1125±10cm -1 The signal peaks at 960±10cm represent the vibration signals of framework titanium. For general titanium silicon molecular sieves, signal peaks can appear at these two locations, indicating that the molecular sieve has framework titanium species. The alkali metal-modified titanium silicon molecular sieve provided by the present invention has a peak at 960±10cm-1 and 1125±10cm -1 There are no obvious characteristic peaks, but at 990±20cm -1 A new characteristic peak appears at the Raman spectrum characterization test of the alkali metal modified titanium silicalite molecular sieve at 325 nm light source in the present invention, and the test method thereof is a conventional method in the art.

[0024] Fourier transform infrared spectroscopy (FT-IR) is one of the important methods for analyzing the molecular sieve framework structure. The spectral bands caused by molecular sieve framework vibration are generally in the mid- and far-infrared regions. The position of the internal vibration spectral bands is not sensitive to changes in the framework structure, while the externally connected vibration spectral bands are more sensitive to structural changes. Literature (Chemical Communications, 1982 (24): 1413-1415.) shows that in the infrared spectrum of TS-1 molecular sieve with MFI structure, 800cm -1 The characteristic peak at 960cm is the skeleton vibration peak. -1 The characteristic peaks at 800cm-1 are the characteristic peaks of the stretching vibration of the Si-O bond in Ti-O-Si, and are also the necessary parameters for the titanium element to enter the molecular sieve framework. For general titanium silicon molecular sieves, signal peaks can appear at these two locations, indicating that the molecular sieve has framework titanium species. The alkali metal-modified titanium silicon molecular sieve provided by the present invention has a peak at 800cm-1. -1 The presence of skeleton vibration peaks indicates that the prepared molecular sieve has an MFI structure, but the peak at 960 cm -1 The characteristic peak at 960±20cm is obviously weak or even disappears, indicating that the alkali metal in the titanium silicon molecular sieve of the present invention interacts with the Si-O or Ti-O species in Ti-O-Si. Therefore, the titanium silicon molecular sieve of the present invention is characterized by IR, and the peak height is used as the intensity calculation, 960±20cm -1 The signal peak intensity at 800±20cm -1 The signal peak intensity ratio at 960 ± 20 cm is I(960) / I(800) < 0.5, preferably < 0.3, more preferably < 0.15, more preferably < 0.05, further preferably < 0.01, and most preferably 960 ± 20 cm -1 In the present invention, the IR spectrum test of the alkali metal-modified titanium silicalite is carried out by a conventional method in the art.

[0025] Based on the above Raman spectrum and infrared spectrum characterization, it can be seen that the alkali metal-containing titanium silicon molecular sieve of the present invention interacts with Si-O or Ti-O in Ti-O-Si to form new catalytic active centers. Therefore, a catalyst having better performance than conventional titanium silicon molecular sieves or alkali metal-containing catalysts can be obtained.

[0026] In the alkali metal-modified titanium silicon molecular sieve 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 further preferably cesium. Preferably, the alkali metal element is in a uniformly dispersed state in the molecular sieve. The molar ratio of titanium atoms to silicon atoms in the molecular sieve is obtained by X-ray fluorescence spectrometer analysis method (XRF). The molar ratio of the alkali metal element to the silicon element in the titanium silicon molecular sieve is (0.001-0.1):1, preferably (0.003-0.06):1, further preferably (0.005-0.05):1, further preferably (0.01-0.04):1, more preferably (0.01-0.03):1. The molar ratio of titanium to silicon is (0.001-0.1):1, preferably (0.003-0.06):1, more preferably (0.005-0.04):1, and even more preferably (0.008-0.02):1.

[0027] The alkali metal-modified titanium silicon molecular sieve of the present invention has a framework structure type that in principle includes any suitable structure type or any suitable combination of structure types. Therefore, the available molecular sieve structure types in principle include the following structure types: ABW, ACO, AEI, AEL, AEN, AET, AFG, AFI, AFN, AFO, AFR, AFS, AFT, AFY, AHT, ANA, APC, APD, AST, ASV, AFX, ATN, ATO, ATS, ATT, ATV, AWO, AWW, BCT, BEA, BEC, BIK, BOF, BOG, BOZ, BPH, BRE, BSV, CAN, CAS, CDO, CFI, CGF, SCO, CFI, SGF, CGS, CHA, CHI, CLO, CON, CZ P, DAC, DDR, DFO, DFT, DOH, DON, EAB, EDI, EWT, EON, EPI, ERI, ESV, ETR, EUO, FAU, FER, FRA, GIS, GIU, GME, GON, GOO, HEU, IFR, IHW, ISV, ITE, I TH, ITW, IWR, IWW, IWV, JBW, JNT, JOZ, JRY, JSN, JSR, JST, JSW, KFI, LAU, LEV, LIO, LIT, LOS, LOV, LTA, LTF, LTJ, LTL, LTN, MAR, MAZ, MEI, MEL, M EP, MER, MFI, MFS, MON, MOR, MOZ, MRT, MSE, MSO, MTF, MTN, MTT, MTW, MVY, MWF, MWW, NAB, NAT, NES, NON, NPO, NPT, NSI, OBW, OFF, OKO, OSI, OSO, OWE, PAR, PAU, PCR, PHI, PON, POR, POS, PSI, PTY, PUN, PWN, PWO, PWW, RHO, RON, RRO, RSN, RTE, RTH, RUT, RWR, RWY, SAF, SAO, SAS, SAT, SAV, SBE, SBN, SBS, SBT, SFE, SFF, SFG, SFH, SFN, SFO, SFS, SFW, SGT, SIV, SOD, SOF, SOR, SOS, SOV, SSF, SSY, STF, STI, STT, STW, SVR, SVV, SWY, SYT, SZR, TER, THO, TOL, TON, TSC, TUN, UEI, UFI, UOS, UOV, UOZ, USI, UTL, UWY, VET, VFI, VNI, VSV, WEI, WEN, YFI, YUG, ZON, and hybrid structures consisting of two or more of these structure types.Preferably, the titanium silicalite molecular sieve has a crystal structure selected from one of MFI, MEL, MWW, BEA, MOR, and SVR, or an amorphous structure, including MCM-41, MCM-48, SBA-15, anatase, rutile, brookite, and amorphous titanium oxide hydrolyzed from other titanium compounds.

[0028] The preferred crystal structure is MFI, MEL, BEA structure, and the further preferred crystal structure is MFI, MEL, BEA structure with multi-level pores. The multi-level pore structure can be formed by direct synthesis or post-processing, for example, it can be synthesized by soft and hard template synthesis methods (silanization method, cellulose method, carbon black method, etc.), and expanded by acid and alkali treatment (for example, by hydrochloric acid, hydrofluoric acid, ammonium bifluoride, ammonium fluoride, sodium hydroxide, potassium hydroxide, ammonia water, ammonium carbonate, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, etc.). The multi-level pore structure can be a molecular sieve containing micropores and at least one mesopore and / or macropore, the micropore diameter is less than 2nm, the mesopore diameter is 2-50nm, and the macropore diameter is greater than 50nm. For example, it can be a titanium silicon molecule HTS with a hollow structure, and it can be a titanium silicon molecular sieve with a non-uniform mesopore distribution.

[0029] The present invention also provides a method for preparing an alkali metal-modified titanium silicon molecular sieve, which is characterized in that the titanium silicon molecular sieve as a modified raw material is mixed with an alkali metal hydroxide or an alkali metal salt and water and / or an organic solvent, and then the water and / or the organic solvent are removed, and then the alkali metal-containing titanium silicon molecular sieve is obtained through drying and roasting, wherein the mixing treatment is carried out at 50-100°C, the gauge pressure is 0.1-5MPa, and the treatment time is 0.5-12h.

[0030] In the preparation method, the titanium silicon molecular sieve used as the modified raw material can be obtained by a hydrothermal synthesis method or a post-synthesis method, and the molar ratio of titanium to silicon elements is preferably (0.001-0.1):1, preferably (0.005-0.06):1, further preferably (0.01-0.04):1, and more preferably (0.015-0.03):1.

[0031] In the preparation method, the alkali metal is selected from one or more of lithium, sodium, potassium, rubidium, and cesium. Preferably, it is one or more of potassium, rubidium, and cesium, more preferably one or more of rubidium and cesium, and further preferably cesium. The hydroxide or salt includes hydroxide, hydrochloride, hypochlorite, chlorite, metachlorate, perchlorate, nitrate, sulfate, hydrogen sulfate, sulfite, hydrogensulfite, phosphate, hydrogen phosphate, dihydrogen phosphate, high phosphate, metaphosphate, phosphite, hypophosphite, carboxylate, pyrophosphate, C1-C 20 One or more of carboxylates and inorganic salts thereof. Preferably, it is a nitrate, carbonate or hydroxide thereof. More preferably, it is one or more of cesium hydroxide, cesium nitrate, cesium carbonate, cesium bicarbonate or cesium acetate.

[0032] In the preparation method, the molar ratio of the alkali metal element to the silicon element of the titanium silicon molecular sieve is preferably (0.001-0.1):1, preferably (0.003-0.06):1, further preferably (0.005-0.05):1, further preferably (0.01-0.04):1, and more preferably (0.01-0.03):1.

[0033] In the preparation method, the organic solvent is selected from C1-C 10 Alcohol, C3-C 10 Ketone, C2-C 10 ester. In addition, the solvent can be an aliphatic solvent or an aromatic solvent. Also additionally, the solvent can be a chlorinated solvent, such as dichloromethane. More typically, the solvent is an aliphatic alcohol, which is typically selected from C1-C6 alkanols, such as methanol, ethanol, propanol, isopropanol, butanol, pentanol and hexanol, more typically, methanol, ethanol or propanol. The amount of the inorganic solvent or organic solvent added is calculated according to the carrier. Preferably, the solvent is preferably at least one of water, methanol, ethanol, and propanol. The molar ratio of the titanium silicon molecular sieve (calculated as SiO2) as a raw material to the solvent is preferably 1: (10-100), further preferably 1: (20-80), more preferably 1: (25-60), more preferably 1: (30-50).

[0034] In the preparation method, the treatment is preferably carried out at 50-100°C, more preferably 55-90°C, and more preferably 60-80°C. The pressure (gauge pressure) is 0.5-5MPa, preferably 0.5-4MPa, more preferably 0.8-3MPa, and more preferably 1.2-2.5MPa. The treatment time is 0.5-12h, preferably 1-8h, and more preferably 2-5h. Treatment under the pressure and temperature conditions can effectively promote the reaction of alkali metals with titanium species of the titanium silicon molecular sieve as a raw material to form an alkali metal-modified titanium silicon molecular sieve with a special active center.

[0035] In the preparation method, the method for removing water and / or organic solvent can be pressure evaporation, normal pressure evaporation, reduced pressure evaporation, filtration, centrifugation, sedimentation, etc., among which reduced pressure evaporation is preferred, and more preferably, water and / or organic solvent is removed under a pressure (absolute pressure) of 10-80KPa.

[0036] In the preparation method, the calcination atmosphere is preferably an oxygen-containing atmosphere, and more preferably an air atmosphere; the calcination temperature is determined according to the decomposition temperature of the alkali element precursor of the modifier, and is preferably <700° C. to prevent the alkali element precursor from decomposing, and the calcination temperature is more preferably 400-600° C. To prevent a significant change in the carrier structure or specific surface area, the calcination time is 0.5-12 hours, and more preferably 3-8 hours.

[0037] The present invention also provides a catalyst containing titanium silicon molecular sieve, which contains the alkali metal-modified titanium silicon molecular sieve of the present invention or the alkali metal-modified titanium silicon molecular sieve prepared by the above preparation method, and the weight ratio of the alkali metal-modified titanium silicon molecular sieve to the catalyst containing titanium silicon molecular sieve is preferably 5%-100%.

[0038] The present invention further provides a method for preparing a carbonyl-containing compound, wherein a carbonyl-containing compound having α-H undergoes a carbon-carbon bond coupling reaction with another carbonyl-containing compound in the presence of a catalyst to generate a carbonyl-containing compound having β-hydroxyl or a carbonyl-containing compound having α,β-unsaturated bonds, characterized in that the catalyst is the catalyst of the titanium-containing silicon molecular sieve provided by the present invention.

[0039] The method for preparing the carbonyl-containing compound is to use the alkali metal-modified titanium silicon molecular catalyst provided by the present invention to catalyze a carbonyl-containing compound having α-H and another carbonyl-containing compound to undergo a carbon-carbon bond coupling reaction to generate a carbonyl-containing compound having β-hydroxyl or a carbonyl-containing compound having α,β-unsaturated bonds (the α and β positions refer to the functional groups of hydrocarbon molecules, such as carbonyl, hydroxyl, carboxyl, etc., and the first ortho and second ortho carbon atoms thereof).

[0040] The carbonyl-containing compound comprises a first carbonyl compound and a second carbonyl compound, and the number of carbon atoms of the carbonyl compound is preferably C1-C 20 .in:

[0041] C1-C 12Alkyl, 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, 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, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isohexyl, sec-butyl, and very particularly preferably methyl.

[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, is 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, and 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, sulfonium, 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 their derivatives, 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 method for preparing the carbonyl compound, the conditions for the aldol condensation reaction are preferably a molar ratio of the second carbonyl compound to the first carbonyl compound of 1: (0.5-5), a further preferred molar ratio of 1: (0.8-4), and a more preferred molar ratio of 1: (1-2). The feed stream also contains one or more diluents, the diluents including at least one of alcohols, ethers, alkanes, halogenated alkanes, and toluene, preferably methanol, cycloalkanes, ether, and toluene. The molar ratio of the diluent to the carbonyl compound is (10-0.5): 1, further preferably (5-0.8): 1, and more preferably (3-1): 1.

[0052] In the method for preparing carbonyl-containing compounds of the present invention, the aldol condensation reaction is 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, more preferably in an atmosphere containing N2.

[0053] In the preparation method of the carbonyl compound of the present invention, the temperature of the aldol condensation reaction is 200-500°C, preferably 250-480°C, more preferably 300-400°C. Before the reaction, the temperature of the mixed solution is preferably raised to between 250-400°C, more preferably between 300-400°C. The reaction pressure is 0.01-2.5MPa, preferably 0.5-1.0MPa. The hourly space velocity of the reaction solution is 0.1-5h based on the total mass of the carbonyl compound and the diluent.-1 , 0.1-3h -1 , more preferably 0.1-2h -1 .

[0054] In the preparation method of the carbonyl-containing compound of the present invention, the formaldehyde source is an anhydrous formaldehyde source, preferably methylal, trioxymethylene and oligoformaldehyde. The inventors unexpectedly found that the catalyst containing titanium silicon molecular sieve provided by the present invention can surprisingly improve the activity and selectivity for the aldol condensation of methylene sources such as formaldehyde and carboxylic acids or hydrocarbon esters such as methyl acetate to form olefinically unsaturated carboxylic acids. Therefore, in an optional specific embodiment, the aldol condensation reaction conditions of formaldehyde and methyl acetate include: methyl acetate: formaldehyde molar ratio of 1:2 to 5:1, methanol: methyl acetate molar ratio of 1:1 to 2:1, reaction temperature of 350 to 400 ° C, reaction pressure (gauge pressure) of 0 to 1 MPa, nitrogen flow rate of 30 to 100 mL / min, reaction liquid hourly space velocity of 0.1 to 2h -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 (in units of (mass / time)) to the mass of the catalyst. Therefore, the unit of the space velocity is h -1 .

[0055] In the method for preparing the carbonyl-containing compound of the present invention, preferably, the aldol condensation reaction is carried out in a fixed bed reactor, a fluidized bed reactor or a tank reactor.

[0056] It is understood by those skilled in the art that, depending on the different reactors used, the molecular sieve catalyst of the present invention can be an alkali metal-modified titanium silicon molecular sieve original powder, or a shaped catalyst after the alkali metal-modified titanium silicon molecular sieve is shaped. The separation of the product and the catalyst can be achieved in a variety of ways. For example, when the original powdered skeleton contains a titanium element molecular sieve as a catalyst, the separation of the product and the recovery and reuse of the catalyst can be achieved by sedimentation, filtration, centrifugation, evaporation, membrane separation, etc. Alternatively, the catalyst can be shaped and loaded into a fixed bed reactor, and the catalyst can be recovered after the reaction is completed. Various catalyst separation and recovery methods are involved in many existing documents, which will not be described here.

[0057] The present invention is described in detail below by way of examples.

[0058] In the embodiment, the UV-Raman characterization experiment instrument of the sample is a LabRAMHRUV-NIR confocal micro-Raman spectrometer produced by JobinYvon, France. Test conditions: room temperature, normal pressure, spectrum collection range 170-1200cm -1Solid sample: The excitation light source wavelength is 325nm, the laser is a HeCd laser produced by Kimmon Company of Japan, and the UV 15x objective lens is used for testing. The single acquisition time is 300s, and the cumulative sampling is 2 times to eliminate fluorescence interference. The microscopic system is composed of a Japanese Olympus microscope. A 100um confocal pinhole is used, and the first-order peak of single crystal silicon (520.7cm -1 ) to correct the peak position.

[0059] In the embodiment, Fourier transform infrared spectroscopy. Instrument: Nicolet 6700 Fourier transform infrared spectrometer, produced by Thermo Fisher Scientific. Test conditions: room temperature and pressure, sample KBr tablet, then put into a homemade in-situ cell, scanning range 400-4000cm -1 .

[0060] In the embodiments, X-ray fluorescence spectrometer (XRF) Instrument: ZSX100E X-ray fluorescence spectrometer, produced by Rigaku Co., Ltd., Japan Test conditions: Test after tableting at room temperature, using tungsten-palladium, excitation voltage of 40Kv, excitation current of 250mA.

[0061] The catalytic performance test was conducted in a fixed bed reactor at atmospheric pressure, with the reaction of methyl acetate and formaldehyde aldol condensation to synthesize methyl acrylate as the probe reaction. 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 -1 The amount of catalyst was 5 g; the carrier gas (N2) flow rate was maintained at 30 mL / min during the reaction, and the reaction temperature was 340° C. The product was condensed and then analyzed by chromatography.

[0062] Unless otherwise specified, the raw materials in the examples were purchased from commercial sources and were pure reagents.

[0063] The product analysis methods in the examples and comparative examples of the present application are as follows:

[0064] 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. The 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.

[0065] In the examples of this application, the conversion rate and selectivity are calculated as follows:

[0066]

[0067]

[0068] Comparative Example 1

[0069] This comparative preparation example illustrates the preparation of TS-1 molecular sieve as a comparison.

[0070] Tetraethyl orthosilicate (TEOS), n-butyl titanate [Ti(OBu)4] and tetrapropylammonium hydroxide (TPAOH, 26.5wt%) solution are mixed in a molar ratio of SiO2:0.01TiO2:0.36TPAOH:35H2O, and then stirred for 15 minutes to obtain a clear liquid. Finally, water is added to the clear liquid, stirred at 348-353K for about 3 hours to obtain a clear sol, which is then crystallized at 443K for 3 days. The obtained solid is then filtered, washed with distilled water, dried at 373K for 5 hours, and then calcined at 823K for 5 hours to obtain the TS-1 molecular sieve, numbered TS-1-0.01.

[0071] The characterization and evaluation data are shown in Table 1.

[0072] The IR spectrum of sample TS-1-0.01 is shown in Figure 1 TS-1 curve in, UV-Raman spectrum see Figure 2 TS-1 curve in .

[0073] Comparative Example 2

[0074] This preparation comparative example illustrates the preparation of Cs / SiO2 catalyst.

[0075] Preparation of SiO2: Mix 100 mL of water and tetraethyl silicate at room temperature, add aqueous ammonia to the mixture dropwise until pH = 13, then stir at 30°C for 30 min, filter the hydrolyzed silica, dry it in a drying oven at 110°C overnight, cool it to room temperature and grind it to obtain carrier silica.

[0076] The specific steps of Cs / SiO2 catalyst are as follows: weigh a certain amount of cesium nitrate and dissolve it in deionized water, then immerse 10g of silica in deionized water, the molar ratio of cesium to silicon is 0.01, and the molar ratio of silica to solvent is 1:80. Treat at normal pressure and 25℃ for 1h to make cesium ions evenly distributed on silica, evaporate excess water, dry it in a drying oven for 6h, and calcine it in a muffle furnace at 400℃ for 6h. Characterization and evaluation data are shown in Table 1.

[0077] Example 1

[0078] Example 1 illustrates the base-modified titanium silicate molecular sieve of the present invention and its preparation.

[0079] Weigh a certain amount of cesium nitrate and dissolve it in deionized water. Then, 10g of the molecular sieve numbered TS-1-0.01 prepared in Comparative Example 1 was impregnated. The molar ratio of cesium to silicon was 0.01, and the molar ratio of the molecular sieve (in terms of silicon dioxide) to the solvent was 1:80. Treat at 1MPa and 50°C for 1h to evenly distribute the cesium ions on the titanium silicon molecular sieve, evaporate the excess water, dry it in a drying oven at 100°C for 10h, and calcine it in a muffle furnace at 400°C for 4h. The characterization and evaluation data are shown in Table 1.

[0080] The IR spectrum of the sample is shown in Figure 1 Cs / TS-1 curve in, UV-Raman spectrum see Figure 2 Cs / TS-1 curve in.

[0081] Example 2

[0082] Example 2 illustrates the base-modified titanium silicate molecular sieve of the present invention and its preparation.

[0083] Weigh a certain amount of cesium nitrate and dissolve it in deionized water. Then, 10g of the molecular sieve numbered TS-1-0.01 prepared in Comparative Example 1 was impregnated. The molar ratio of cesium to silicon was 0.04, and the molar ratio of the molecular sieve (in terms of silicon dioxide) to the solvent was 1:60. Treat at 1MPa and 50°C for 1.5h to evenly distribute the cesium ions on the titanium silicon molecular sieve. Evaporate excess water, dry it in a drying oven at 100°C for 6h, and calcine it in a muffle furnace at 400°C for 6h. The characterization and evaluation data are shown in Table 1.

[0084] Comparative Example 3

[0085] This comparative example illustrates the preparation of TS-1 molecular sieve as a comparison.

[0086] Tetraethyl orthosilicate (TEOS), n-butyl titanate [Ti(OBu)4] and tetrapropylammonium hydroxide (TPAOH, 26.5wt%) solution were mixed in a molar ratio of SiO2: 0.03TiO2: 0.36TPAOH: 20H2O, 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 5 hours to obtain a molecular sieve, numbered TS-1-0.03. Characterization and evaluation data are shown in Table 1.

[0087] Example 3

[0088] Example 3 illustrates the base-modified titanium silicate molecular sieve of the present invention and its preparation.

[0089] Weigh a certain amount of cesium nitrate and dissolve it in deionized water. Then, 10g of the molecular sieve numbered TS-1-0.03 prepared in Comparative Example 3 was impregnated. The molar ratio of cesium to silicon was 0.02, and the molar ratio of the molecular sieve (in terms of silicon dioxide) to the solvent was 1:30. Treat at 2MPa and 70°C for 3h to make the cesium ions evenly distributed on the titanium silicon molecular sieve. Evaporate the excess solvent under reduced pressure, dry it in a drying oven at 100°C for 6h, and calcine it in a muffle furnace at 450°C for 4h. The characterization and evaluation data are shown in Table 1.

[0090] Example 4

[0091] Example 4 illustrates the base-modified titanium silicate molecular sieve of the present invention and its preparation.

[0092] Weigh a certain amount of cesium acetate and dissolve it in deionized water. Then, 10g of the molecular sieve numbered TS-1-0.03 prepared in Comparative Example 3 was impregnated. The molar ratio of cesium to silicon was 0.018, and the molar ratio of the molecular sieve (in terms of silicon dioxide) to the solvent was 1:40. Treat at 2MPa and 60°C for 2h to make the cesium ions evenly distributed on the titanium silicon molecular sieve, evaporate the excess water, dry it in a drying oven at 100°C for 2h, and calcine it in a muffle furnace at 450°C for 4h. The characterization and evaluation data are shown in Table 1.

[0093] Example 5

[0094] Example 5 illustrates the base-modified titanium silicalite of the present invention and its preparation.

[0095] Weigh a certain amount of cesium nitrate and dissolve it in isopropanol, then impregnate 10g of the molecular sieve numbered TS-1-0.03 prepared in Comparative Example 3, the molar ratio of cesium to silicon is 0.015, and the molar ratio of the molecular sieve (in terms of silicon dioxide) to the solvent is 1:50. Treat at 1.5MPa and 60℃ for 2h to make the cesium ions evenly distributed on the titanium silicon molecular sieve, evaporate the excess water, dry it in a drying oven at 100℃ for 6h, and calcine it in a muffle furnace at 400℃ for 6h. Characterization and evaluation data are shown in Table 1.

[0096] Comparative Example 4

[0097] Comparative Example 4 illustrates the preparation of a hierarchical pore titanium silicalite HTS for comparison.

[0098] The HTS molecular sieve was prepared according to the method described in Example 1 of the specification of Chinese patent CN1301599A, with a titanium-silicon molar ratio of 0.03. The characterization and evaluation data are shown in Table 1.

[0099] Comparative Example 5

[0100] Comparative Example 5 illustrates the preparation of Cs / SBA-15 for comparison.

[0101] Weigh a certain amount of cesium nitrate and dissolve it in deionized water. Add 10g of SBA-15 molecular sieve to the cesium nitrate solution. The molar ratio of cesium to silicon is 0.015, and the molar ratio of molecular sieve (in terms of silicon dioxide) to solvent is 1:50. Treat at 1.5MPa and 60℃ for 2h to evenly distribute cesium ions on the SBA-15 molecular sieve, evaporate excess water, dry it in a drying oven at 110℃ for 6h, and calcine it in a muffle furnace at 400℃ for 6h. Characterization and evaluation data are shown in Table 1.

[0102] Example 6

[0103] Example 6 illustrates the base-modified titanium silicate molecular sieve of the present invention and its preparation.

[0104] Weigh a certain amount of cesium nitrate and dissolve it in water, then impregnate 10g of the HTS molecular sieve prepared in Comparative Example 4, the molar ratio of cesium to silicon is 0.015, and the molar ratio of molecular sieve (in terms of silicon dioxide) to solvent is 1:50. Treat at 2MPa and 60℃ for 2h to make the cesium ions evenly distributed on the titanium silicon molecular sieve, evaporate excess water, dry in a drying oven for 6h, and calcine in a muffle furnace at 400℃ for 6h. Characterization and evaluation data are shown in Table 1.

[0105] Example 7

[0106] Example 7 illustrates the base-modified titanium silicalite of the present invention and its preparation.

[0107] A certain amount of cesium carbonate was weighed and dissolved in water, and then 10g of the HTS molecular sieve prepared in Comparative Example 4 was impregnated, the molar ratio of cesium to silicon was 0.03, and the molar ratio of molecular sieve (in terms of silicon dioxide) to solvent was 1:40. The cesium ions were evenly distributed on the titanium silicon molecular sieve at 1.5MPa and 80°C for 3h, and the excess water was evaporated under reduced pressure at an absolute pressure of 20KPa, and the product was calcined at 400°C in a muffle furnace for 6h. The characterization and evaluation data are shown in Table 1.

[0108] Example 8

[0109] Example 8 illustrates the base-modified titanium silicalite of the present invention and its preparation.

[0110] Weigh a certain amount of cesium nitrate and dissolve it in water, then impregnate 10g of the HTS molecular sieve prepared in Comparative Example 4, the molar ratio of cesium to silicon is 0.02, and the molar ratio of molecular sieve (in terms of silicon dioxide) to solvent is 1:50. Treat at 2MPa and 60℃ for 2h to make the cesium ions evenly distributed on the titanium silicon molecular sieve, evaporate excess water, dry it in a drying oven at 110℃ for 6h, and calcine it in a muffle furnace at 400℃ for 6h. Characterization and evaluation data are shown in Table 1.

[0111] Example 9

[0112] Example 9 illustrates the base-modified titanium silicalite of the present invention and its preparation.

[0113] A certain amount of cesium nitrate was weighed and dissolved in ethanol, and then 10g of the HTS molecular sieve prepared in Comparative Example 4 was impregnated. The molar ratio of cesium to silicon was 0.025, and the molar ratio of molecular sieve (in terms of silicon dioxide) to solvent was 1:30. The cesium ions were evenly distributed on the titanium silicon molecular sieve at 2.5MPa and 70°C for 3h, and the excess ethanol was evaporated under reduced pressure at an absolute pressure of 20KPa, and calcined in a muffle furnace at 400°C for 4h. The characterization and evaluation data are shown in Table 1.

[0114] Example 10

[0115] Example 10 illustrates the base-modified titanium silicalite of the present invention and its preparation.

[0116] Weigh a certain amount of cesium nitrate and dissolve it in water, then impregnate it with 10g of the HTS molecular sieve prepared in Comparative Example 4. The molar ratio of cesium to silicon is 0.022, and the molar ratio of molecular sieve (in terms of silicon dioxide) to solvent is 1:50. Treat at 2MPa and 60℃ for 2h to make the cesium ions evenly distributed on the titanium silicon molecular sieve, evaporate excess water, dry it in a drying oven at 110℃ for 6h, and calcine it in a muffle furnace at 400℃ for 6h. Characterization and evaluation data are shown in Table 1.

[0117] Table 1

[0118]

[0119]

[0120] As can be seen from Table 1, the alkali-modified titanium silicalite of the present invention has good conversion rate and product selectivity when catalyzing the aldol condensation reaction of methyl acetate and formaldehyde to prepare methyl acrylate, which is particularly reflected in that the types and quantities of by-products are very small. In addition to the main product methyl acrylate, the by-products are acrolein, methacrolein and a small amount of methyl propionate, all of which are valuable compounds.

[0121] The above descriptions are only representative embodiments of the present invention and are 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 protection scope of the present invention.

Claims

1. An alkali metal-modified titanium silicon molecular sieve, characterized in that: The molecular sieve contains titanium, silicon, oxygen and alkali metal elements. The Raman spectrum of the molecular sieve under 325nm light source is 990±20cm -1 There is a titanium species signal peak in the range of 1125±20cm -1 There is no obvious titanium species signal peak in the range of 800±20cm -1 There is a molecular sieve framework structure signal peak in the range, calculated by peak area, 990±20cm -1 Signal peak intensity and 800±20cm -1 The ratio of signal peak intensity I(990) / I(800) is (0.2-2):

1.

2. The titanium silicon molecular sieve according to claim 1, characterized in that: Characterized by Raman spectroscopy at 325 nm, 990 ± 20 cm -1 Signal peak intensity and 800±20cm -1 The ratio of signal peak intensities is (0.5-1.6):1, preferably (0.8-1.3):

1.

3. The titanium silicon molecular sieve according to claim 1, characterized in that: Characterized by IR, intensity calculated based on peak height, 960±20cm -1 The signal peak intensity at 800±20cm -1 The ratio of the signal peak intensity at I(960) / I(800) is less than 0.

5.

4. The titanium silicon molecular sieve according to claim 1, characterized in that: 960±20cm -1 The signal peak intensity at 800±20cm -1 The ratio of the signal peak intensity at I(960) / I(800) is <0.3, preferably <0.15, more preferably <0.05, and further preferably <0.

01.

5. The titanium silicon molecular sieve according to claim 1, characterized in that: Characterized by IR, 960±20cm -1 No signal peaks.

6. The titanium silicon molecular sieve according to claim 1, characterized in that: The alkali metal element is selected from one or more of lithium, sodium, potassium, rubidium and cesium.

7. The titanium silicon molecular sieve according to claim 1, characterized in that: The molar ratio of the alkali metal element to the silicon element in the titanium silicon molecular sieve is (0.001-0.1):1, preferably (0.003-0.06):1, further preferably (0.005-0.05):1, more preferably (0.01-0.04):1, and most preferably (0.01-0.03):

1.

8. The titanium silicon molecular sieve according to claim 1, characterized in that: The molar ratio of titanium to silicon is (0.001-0.1):1, preferably (0.003-0.06):1, more preferably (0.005-0.04):1, and even more preferably (0.008-0.02):

1.

9. The titanium silicon molecular sieve according to claim 1, characterized in that: It has a crystalline structure selected from one of MFI, MEL, MWW, BEA, MOR, and SVR, or has an amorphous structure selected from one of MCM-41, MCM-48, and SBA-15.

10. The titanium silicon molecular sieve according to claim 1, characterized in that: MFI, MEL, BEA structures with multi-level pores, wherein the multi-level pores include micropores and at least one mesopore and / or macropore, wherein the micropore diameter is less than 2nm, the mesopore diameter is 2-50nm, and the macropore diameter is greater than 50nm.

11. The method for preparing the alkali metal-modified titanium silicon molecular sieve according to any one of claims 1 to 9, characterized in that: The titanium silicon molecular sieve as the modified raw material is mixed with the hydroxide of the alkali metal or the salt of the alkali metal and water and / or an organic solvent, and then the water and / or the organic solvent are removed, and then the alkali metal-containing titanium silicon molecular sieve is obtained through drying and calcination, wherein the mixing treatment is carried out at 50-100°C and a gauge pressure of 0.1-5MPa for 0.5-12h.

12. The preparation method according to claim 11, characterized in that: The titanium silicalite molecular sieve used as the modified raw material has a crystal structure of one of MFI, MEL, MWW, BEA, MOR and SVR; or The titanium silicalite molecular sieve used as the modified raw material has an amorphous structure of one of MCM-41, MCM-48 and SBA-15.

13. The preparation method according to claim 11, characterized in that: The titanium silicon molecular sieve used as the modified raw material is obtained by a hydrothermal synthesis method.

14. The preparation method according to claim 11, characterized in that: The titanium-silicon molecular sieve used as the modified raw material has a molar ratio of titanium to silicon of (0.001-0.1):

1.

15. The preparation method according to claim 11, characterized in that: 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 rubidium and / or cesium, and further preferably cesium.

16. The preparation method according to claim 11, characterized in that: The alkali metal salt is an alkali metal hydrochloride, hypochlorite, chlorite, metachlorate, perchlorate, nitrate, sulfate, hydrogen sulfate, sulfite, bisulfite, phosphate, hydrogen phosphate, dihydrogen phosphate, high phosphate, metaphosphate, phosphite, hypophosphite, carboxylate, pyrophosphate, C1-C 20 One or more of the carboxylates.

17. The preparation method according to claim 11, characterized in that: The hydroxide of the alkali metal is cesium hydroxide, and the salt of the alkali metal is selected from one or more of cesium nitrate, cesium carbonate, cesium bicarbonate, and cesium acetate.

18. The preparation method according to claim 11, characterized in that: The molar ratio of the titanium silicon molecular sieve, alkali metal hydroxide or alkali metal salt, water and / or organic solvent used as the modification raw material is 1: (0.001-0.1): (10-100), wherein the titanium silicon molecular sieve used as the modification raw material is calculated as SiO2, and the alkali metal hydroxide or alkali metal salt is calculated as alkali metal.

19. The preparation method according to claim 11 or 18, characterized in that: The organic solvent is selected from C1-C 10 Alcohol, C3-C 10 Ketone, C2-C 10 of esters.

20. The preparation method according to claim 11, characterized in that: The gauge pressure is 0.5-4 MPa, preferably 0.8-3 MPa, more preferably 1.2-2.5 MPa; the treatment time is 1-8 h, preferably 2-5 h.

21. A catalyst containing titanium silicon molecular sieve, characterized in that: The catalyst contains the alkali metal modified titanium silicon molecular sieve described in claims 1-10 or contains the alkali metal modified titanium silicon molecular sieve prepared by the preparation method described in any one of claims 11-20.

22. The catalyst according to claim 21, characterized in that The alkali metal modified titanium silicon molecular sieve accounts for 5% to 100% of the weight of the catalyst.

23. A method for preparing a carbonyl-containing compound, wherein a carbonyl-containing compound having α-H and another carbonyl-containing compound undergo a carbon-carbon bond coupling reaction in the presence of a catalyst to generate a carbonyl-containing compound having β-hydroxyl or a carbonyl-containing compound having α,β-unsaturated bonds, characterized in that: The catalyst is the catalyst according to claim 21 or 22.

24. The method according to claim 28, characterized in that It is the aldol condensation reaction of methyl acetate and formaldehyde.

25. The method according to claim 24, characterized in that The aldol condensation reaction conditions include: a molar ratio of methyl acetate to formaldehyde of 1:2 to 5:1, a molar ratio of methanol to methyl acetate of 1:1 to 2:1, a reaction temperature of 320 to 400°C, a reaction 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 .

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