CN111253232B - Method for preparing methylglyoxal - Google Patents

Method for preparing methylglyoxal Download PDF

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CN111253232B
CN111253232B CN201811459264.8A CN201811459264A CN111253232B CN 111253232 B CN111253232 B CN 111253232B CN 201811459264 A CN201811459264 A CN 201811459264A CN 111253232 B CN111253232 B CN 111253232B
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molecular sieve
tin
reaction
sugar
alcohol
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CN111253232A (en
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刘聿嘉
赵毅
夏长久
林民
朱斌
罗一斌
舒兴田
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Sinopec Research Institute of Petroleum Processing
China Petroleum and Chemical Corp
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China Petroleum and Chemical Corp
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C45/00—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds
    • C07C45/61—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by reactions not involving the formation of >C = O groups
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J29/00—Catalysts comprising molecular sieves
    • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
    • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
    • B01J29/80—Mixtures of different zeolites
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00—Catalysts, in general, characterised by their form or physical properties
    • B01J35/19—Catalysts containing parts with different compositions
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C45/00—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds
    • C07C45/56—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds from heterocyclic compounds
    • C07C45/57—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds from heterocyclic compounds with oxygen as the only heteroatom
    • C07C45/60—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds from heterocyclic compounds with oxygen as the only heteroatom in six-membered rings
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C45/00—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds
    • C07C45/61—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by reactions not involving the formation of >C = O groups
    • C07C45/67—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by reactions not involving the formation of >C = O groups by isomerisation; by change of size of the carbon skeleton
    • C07C45/673—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by reactions not involving the formation of >C = O groups by isomerisation; by change of size of the carbon skeleton by change of size of the carbon skeleton

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Abstract

The invention relates to a method for preparing methylglyoxal, which comprises the following steps: contacting sugar with a catalyst in a reactor in the presence of alcohol and carrying out a reaction to obtain a product containing methylglyoxal; wherein the molar ratio of sugar to alcohol is 1: (50-600), the reaction temperature is more than 100 ℃ and less than 150 ℃, the reaction time is 10-50h, the catalyst contains a mixture of titanium silicalite and tin silicalite, and the weight ratio of sugar to the mixture of titanium silicalite and tin silicalite on a dry basis is 1: (0.1-6). The process of the present invention has high sugar conversion and methylglyoxal yield.

Description

Method for preparing methylglyoxal
Technical Field
The invention relates to a method for preparing methylglyoxal.
Background
Methylglyoxal is an aldehyde compound, also known as methylglyoxal, 2-oxopropanal. The form is yellow or yellowBrown transparent liquid, pungent smell, and hygroscopic property. Density 1.200g/cm 3 Melting point 25 ℃, boiling point 72 ℃ and refractive index 1.4209. The substance is easy to polymerize into viscous semisolid, is dissolved in water to release heat, and is recovered into monomer solution. Heating at 72 deg.C to form yellow green gas, and maintaining in closed tube for several days, wherein the product is generally 20% -40% water solution. It can be used as intermediate of medicine and pesticide and biochemical reagent, and also can be used as raw material of cimetidine, lactic acid, pyruvic acid, analgesic, anticancer, antihypertensive, desensitizer and cosmetic.
The traditional methods for producing methylglyoxal include acetone method, propylene glycol method, glycerin catalytic dehydrogenation method and hydroxyacetone catalytic dehydrogenation method. Acetone is commonly used in industrial production to produce methylglyoxal by the acetone method, which usually contains acetone aldoxime, acetone hydroxylamine and other by-products, and also uses acetonitrile and other toxic reagents. Liquid phase oxidation of propylene glycol is also one of the possible processes, but this process has low product yield and complex product. The product obtained by the gas-solid phase catalytic oxidation of propylene glycol has good quality and high yield, the process key lies in the development of the catalyst, a noble metal catalyst is required to be used, and the cost is higher. The catalytic dehydrogenation of glycerol also requires the use of costly noble metal catalysts. The yield of the product and the conversion rate of the reactant are both high in the gas-phase catalytic oxidation of the hydroxyacetone, but the hydroxyacetone reactant is not easy to obtain.
Disclosure of Invention
The object of the present invention is to provide a process for the preparation of methylglyoxal which has a high conversion of sugars and a high yield of methylglyoxal.
In order to achieve the above object, the present invention provides a method for preparing methylglyoxal, which comprises:
contacting sugar with a catalyst in a reactor in the presence of alcohol and carrying out reaction to obtain a product containing methylglyoxal; wherein the molar ratio of sugar to alcohol is 1: (50-600), the reaction temperature is more than 100 ℃ and less than 150 ℃, the reaction time is 10-50h, the catalyst contains a mixture of titanium-silicon molecular sieves and tin-silicon molecular sieves, and the weight ratio of sugar to the mixture of the titanium-silicon molecular sieves and the tin-silicon molecular sieves on a dry basis is 1: (0.1-6).
Optionally, the tin-silicon molecular sieve is selected from one or more of an MFI type tin-silicon molecular sieve, an MEL type tin-silicon molecular sieve, a BEA type tin-silicon molecular sieve, an MWW type tin-silicon molecular sieve, an MOR type tin-silicon molecular sieve, a hexagonal structure tin-silicon molecular sieve and an FAU type tin-silicon molecular sieve.
Optionally, the titanium silicalite molecular sieve is selected from one or more of an MFI type titanium silicalite molecular sieve, an MEL type titanium silicalite molecular sieve, a BEA type titanium silicalite molecular sieve, an MWW type titanium silicalite molecular sieve, an MOR type titanium silicalite molecular sieve, a TUN type titanium silicalite molecular sieve and a hexagonal structure titanium silicalite molecular sieve.
Optionally, the tin-silicon molecular sieve is selected from one or more of Sn-MFI molecular sieve, sn-MEL molecular sieve, sn-Beta molecular sieve, sn-MCM-22 molecular sieve, sn-MOR molecular sieve, sn-MCM-41 molecular sieve, sn-SBA-15 molecular sieve and Sn-USY molecular sieve.
Optionally, the titanium silicalite molecular sieve is selected from one or more of a TS-1 molecular sieve, a TS-2 molecular sieve, a Ti-Beta molecular sieve, a Ti-MCM-22 molecular sieve, a Ti-MOR molecular sieve, a Ti-TUN molecular sieve, a Ti-MCM-41 molecular sieve, a Ti-SBA-15 molecular sieve and a Ti-ZSM-48 molecular sieve.
Optionally, the weight ratio of the titanium-silicon molecular sieve to the tin-silicon molecular sieve in the catalyst is 1: (0.1-10).
Optionally, the molar ratio of titanium dioxide to silicon dioxide in the titanium silicalite molecular sieve is (0.01-10): 100, preferably (0.05-5): 100;
the molar ratio of tin dioxide to silicon dioxide in the tin-silicon molecular sieve is (0.01-10): 100, preferably (0.05-5): 100.
Optionally, the sugar is one or more selected from pentoses, hexoses and disaccharides, the pentoses are xylose, the hexoses are one or more selected from glucose, fructose and mannose, and the disaccharides are sucrose;
the alcohol is one or more selected from monohydric alcohol, dihydric alcohol and polyhydric alcohol containing more than three hydroxyl groups; the monohydric alcohol is selected from one or more of methanol, ethanol, propanol, n-butanol, isobutanol and pentanol, the dihydric alcohol is selected from one or more of ethylene glycol, propylene glycol, butanediol and hexanediol, and the polyhydric alcohol is selected from one or more of glycerol, trimethylolethane, pentaerythritol, xylitol and sorbitol.
Optionally, the molar ratio of sugar to alcohol is 1: (100-500), wherein the weight ratio of the sugar to the mixture of titanium silicalite molecular sieves and tin silicalite molecular sieves is 1: (0.2-3), the reaction temperature is 110-140 ℃, the reaction time is 12-40h, the reaction pressure is 0.1-6MPa, and the reaction pressure is preferably 0.1-4MPa.
Optionally, the reactor is a tank reactor, a fixed bed reactor, a moving bed, a suspended bed or a slurry bed reactor.
The method adopts the catalyst containing the mixture of the tin-silicon molecular sieve and the titanium-silicon molecular sieve, and the framework tin atoms of the tin-silicon molecular sieve and the framework titanium atoms of the titanium-silicon molecular sieve catalyze sugar to perform a reverse aldol condensation reaction to generate dihydroxyacetone, so that ketocarbonyl in the dihydroxyacetone is further activated to generate methylglyoxal, and the reaction efficiency is improved. Compared with the prior art, the method can obtain higher sugar conversion rate and methylglyoxal yield under mild reaction conditions in a short time, has lower energy consumption for subsequent separation of products, is safer and more efficient in process, and is suitable for large-scale industrial production and application.
Additional features and advantages of the invention will be set forth in the detailed description which follows.
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The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:
FIG. 1 is a diagram of the reaction mechanism involved in the conversion of sugars to methylglyoxal according to the present invention.
Detailed Description
The following describes in detail specific embodiments of the present invention. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.
In the present invention, the dry weight refers to the weight measured after the sample is baked at 550 ℃ for 3 hours.
The invention provides a method for preparing methylglyoxal, which comprises the following steps: contacting sugar with a catalyst in a reactor in the presence of alcohol and carrying out reaction to obtain a product containing methylglyoxal; wherein the molar ratio of sugar to alcohol is 1: (50-600), the reaction temperature is more than 100 ℃ and less than 150 ℃, the reaction time is 10-50h, the catalyst contains a mixture of titanium silicalite and tin silicalite, and the weight ratio of sugar to the mixture of titanium silicalite and tin silicalite on a dry basis is 1: (0.1-6). The reaction mechanism is shown in figure 1.
According to the invention, the tin-silicon molecular sieve is a molecular sieve obtained by replacing a part of silicon atoms in a lattice framework of the molecular sieve with tin atoms, the titanium-silicon molecular sieve is a molecular sieve obtained by replacing a part of silicon atoms in a lattice framework of the molecular sieve with titanium atoms, and a mechanical mixture obtained by mechanically mixing the two molecular sieves is used as a catalyst or a component of the catalyst. The content of tin atoms and titanium atoms in the molecular sieve can be measured by adopting an XRF method which is conventional in the field, and the content of the tin atoms and the titanium atoms in the framework of the molecular sieve can be measured by adopting an ultraviolet spectrum or an infrared spectrum, for example, a tin-silicon molecular sieve sample is analyzed by using the ultraviolet spectrum, and a characteristic absorption peak of the framework tin atoms appears near 190 nm; when a titanium silicalite molecular sieve sample is analyzed, a characteristic absorption peak of a framework Ti atom appears near 210 nm. Pyridine infrared spectrum at 1450cm -1 The peaks in (b) represent the L acidic character of the molecular sieve, provided by framework tin atoms and framework titanium atoms.
According to the invention, the tin-silicon molecular sieve is a product of tin atoms replacing part of framework silicon of various topological structure molecular sieves, the topological structure of the molecular sieve can refer to the website of International Zeolite Association (IZA), for example, the tin-silicon molecular sieve can be selected from one or more of MFI type tin-silicon molecular sieve, MEL type tin-silicon molecular sieve, BEA type tin-silicon molecular sieve, MWW type tin-silicon molecular sieve, MOR type tin-silicon molecular sieve, hexagonal structure tin-silicon molecular sieve and FAU type tin-silicon molecular sieve. The MFI type tin-silicon molecular sieve is Sn-MFI molecular sieve, MEL type tin-silicon molecular sieve is Sn-MEL molecular sieve, BEA type tin-silicon molecular sieve is Sn-Beta molecular sieve, MWW type tin-silicon molecular sieve is Sn-MCM-22 molecular sieve, MOR type tin-silicon molecular sieve is Sn-MOR molecular sieve, hexagonal structure tin-silicon molecular sieve is Sn-MCM-41 molecular sieve, sn-SBA-15 molecular sieve, FAU type tin-silicon molecular sieve is Sn-USY molecular sieve. The specific preparation method of the tin-silicon molecular sieve can refer to chinese patents CN104549549A, CN107162014A, CN105271294A, CN103964461A, CN105314649A, CN104557629A, CN104557632A, CN103204806A, CN103204830A, CN 103204775775A, CN103204792A, CN103204777A, CN103204835A, etc. Further preferably, the tin-silicon molecular sieve is an MFI-type tin-silicon molecular sieve. The MFI-type tin-silicon molecular sieves are commercially available or can be prepared according to the methods of the literature (Mal N K, ramasumamy V, rajamohanan P R, et al. Sn-MFI molecular sieves: synthesis methods,29Si liquid and solid MAS-NMR,119Sn static and MAS NMR students [ J ]. Microporous Materials,1997,12 (4-6): 331-340 ].
According to the invention, the titanium silicalite molecular sieve is a product of titanium atoms replacing part of framework silicon of molecular sieves with various topological structures, and the titanium silicalite molecular sieve can be one or more selected from MFI type titanium silicalite molecular sieve, MEL type titanium silicalite molecular sieve, BEA type titanium silicalite molecular sieve, MWW type titanium silicalite molecular sieve, MOR type titanium silicalite molecular sieve, TUN type titanium silicalite molecular sieve and hexagonal structure titanium silicalite molecular sieve. The MFI type titanium silicalite molecular sieve is TS-1 molecular sieve, MEL type titanium silicalite molecular sieve is TS-2 molecular sieve, BEA type titanium silicalite molecular sieve is Ti-Beta molecular sieve, MWW type titanium silicalite molecular sieve is Ti-MCM-22 molecular sieve, MOR type titanium silicalite molecular sieve is Ti-MOR molecular sieve, TUN type titanium silicalite molecular sieve is Ti-TUN molecular sieve, hexagonal structure titanium silicalite molecular sieve is Ti-MCM-41 molecular sieve, ti-SBA-15 molecular sieve, other structure titanium silicalite molecular sieve is Ti-ZSM-48 molecular sieve. Reference may be made to chinese patents CN107879357A, CN107879354A, CN107879356A, CN107879355A, CN107986293A, CN107986294A, CN108002404A, CN 107539539999A, CN107537559A, CN107539998A, CN103182323A, CN103183355A, CN 106964404400A, CN106904633A, CN107986292A, CN103182320A, CN103182322A, CN103183356A, CN101439300A, CN106145151A, CN107840347A, CN106145148A, CN106145149A, CN106145147A and CN107840344A, etc., for the specific preparation of the titanium silicalite molecular sieve, preferably at least one molecular sieve selected from MFI-type titanium silicalite molecular sieves, MEL-type titanium silicalite molecular sieves and BEA-type titanium silicalite molecular sieves. Further preferably, the titanium silicalite molecular sieve is an MFI-type titanium silicalite molecular sieve. The MFI-type titanium silicalite molecular sieves are commercially available or can be prepared according to literature procedures (Studies on the synthesis of titanium silicalite, TS-1Zeolite, 1992,12 (8), 943-50).
The invention generates pyruvaldehyde by the synergetic catalysis of framework titanium atoms of a titanium-silicon molecular sieve and framework tin atoms of a tin-silicon molecular sieve, the titanium-silicon molecular sieve and the tin-silicon molecular sieve in the catalyst can be mixed in any proportion, and preferably, the mixing weight ratio of the titanium-silicon molecular sieve to the tin-silicon molecular sieve in the catalyst is 1: (0.001-1000), and further preferably, the mixing weight ratio of the titanium silicalite molecular sieves and the tin silicalite molecular sieves in the catalyst is 1: (0.01-100), and more preferably, the mixing weight ratio of the titanium silicalite molecular sieves and the tin silicalite molecular sieves in the catalyst is 1: (0.1-10).
According to the present invention, titanium atoms and tin atoms may be substituted for a portion of the silicon atoms in the molecular sieve, for example, the titanium silicalite may have a molar ratio of titania to silica of (0.01-10): 100, preferably (0.05-5): 100; the molar ratio of tin dioxide to silicon dioxide in the tin-silicon molecular sieve can be (0.01-10): 100, preferably (0.05-5): 100.
According to the present invention, the sugar and the alcohol are well known to those skilled in the art, for example, the sugar is one or more selected from the group consisting of a pentose, a hexose and a disaccharide, the pentose is xylose, the hexose is one or more selected from the group consisting of glucose, fructose and mannose, and the disaccharide is sucrose; the alcohol may be one or more selected from monohydric alcohol, dihydric alcohol and polyhydric alcohol containing more than three hydroxyl groups; the monohydric alcohol may be one or more selected from methanol, ethanol, propanol, n-butanol, isobutanol and pentanol, preferably methanol, the dihydric alcohol may be one or more selected from ethylene glycol, propylene glycol, butylene glycol and hexylene glycol, and the polyhydric alcohol may be one or more selected from glycerol, trimethylolethane, pentaerythritol, xylitol and sorbitol.
According to the invention, the molar ratio of sugar to alcohol is preferably 1: (100-500), the weight ratio of sugar to the mixture of titanium silicalite and tin silicalite on a dry basis is preferably 1: (0.2-3), the reaction temperature is preferably 110-140 ℃, the reaction time is preferably 12-40h, the reaction pressure (absolute pressure) is 0.1-6MPa, and the reaction pressure is preferably 0.1-4MPa.
The reaction according to the present invention may be carried out in a conventional catalytic reactor, and the present invention is not particularly limited, for example, the reaction according to the present invention may be carried out in a batch tank reactor, or in other suitable reactors such as fixed bed, moving bed, suspended bed, etc., preferably in a tank reactor, fixed bed reactor, moving bed, suspended bed or slurry bed reactor, the specific operation of which is well known to those skilled in the art, and the present invention will not be described in detail.
According to the present invention, it can be understood by those skilled in the art that, depending on the reactor used, the tin-silicon molecular sieve and/or the titanium-silicon molecular sieve of the present invention may be raw molecular sieve powder, or may be a molded catalyst formed by mixing a molecular sieve and a carrier. The separation of the product containing methylglyoxal from the catalyst can be achieved in various ways, for example, when the original powdery molecular sieve is used as the catalyst, the separation of the product and the recovery and reuse of the catalyst can be achieved by settling, filtering, centrifuging, evaporating, membrane separation, or the like, or the catalyst can be molded and then loaded into a fixed bed reactor, and the catalyst is recovered after the reaction is finished.
The present invention is further illustrated by the following examples, which are not intended to limit the scope of the invention.
The starting materials used in the preparation examples, preparation comparative examples, examples and comparative examples were chemically pure reagents, unless otherwise specified.
In the invention, the gas chromatography is adopted to analyze the methylglyoxal in the activity evaluation system, the liquid chromatography is adopted to analyze the sugar in the activity evaluation system, the analysis result is quantified by an internal standard method, and the internal standard substance is naphthalene. Wherein, the analysis conditions of the gas chromatography are as follows: agilent-6890 type chromatograph, HP-5 capillary chromatographic column, sample amount of 0.5 μ L, and sample inlet temperature of 280 deg.C. The column temperature was maintained at 100 ℃ for 2min, then ramped up to 200 ℃ at a rate of 15 ℃/min and maintained for 3min. FID detector, detector temperature 300 ℃. The analysis conditions of the liquid chromatography are as follows: an Agilent-1200 type chromatograph, an Aminex HPX-87H chromatographic column, a column temperature of 60 ℃, a differential refractive index detector and 0.005M sulfuric acid as a mobile phase, wherein the flow rate is 0.5mL/min.
In each of the examples and comparative examples:
percent sugar conversion = (moles of sugar in starting material-moles of sugar in product)/moles of sugar in starting material × 100%;
methylglyoxal selectivity% = mol of methylglyoxal in product/(mol of sugar in raw material-mol of sugar in product) × 100%;
the yield of methylglyoxal is% = mol of methylglyoxal in product/mol of sugar in raw material x 100%, i.e. methylglyoxal yield% = methylglyoxal selectivity% × sugar conversion%.
Preparation examples and preparation comparative examples were used to provide catalysts used in the examples and comparative examples.
Preparation of example 1
The preparation method for preparing the Sn-MFI molecular sieve comprises the following steps:
adding tin tetrachloride pentahydrate (SnCl) 4 .5H 2 O) is dissolved in water, the aqueous solution is added with tetraethyl orthosilicate (TEOS) and stirred, tetrapropylammonium hydroxide (TPAOH, 20% aqueous solution) and water are added with stirring, and the stirring is continued for 30 minutes to obtain the chemical composition of 0.03SnO 2 ：SiO 2 :0.45TPA：35H 2 And crystallizing the clear liquid of O at 433K for 2 days, filtering the obtained solid, washing the solid with distilled water, drying the solid for 5 hours at 393K, and roasting the solid for 10 hours at 823K to obtain a molecular sieve sample. Wherein the dosage of TEOS is 15.31g, the dosage of TPAOH is 33.67g, the dosage of SnCl is 4 .5H 2 The amount of O was 0.38g and the amount of water was 39.64g.
Preparation of example 2
The Sn-Beta molecular sieves prepared according to the methods of references "Nemeth L, moscoso J, erdman N, et al, synthesis and characterization of Sn-Beta as a selective oxidation catalyst [ J ]. Studies in Surface Science & Catalysis,2004,154 (04): 2626-2631" of the present preparation examples were prepared by:
the pentahydrate stannic chloride (SnCl) 4 .5H 2 O) is dissolved in water, the aqueous solution is added to tetraethyl orthosilicate (TEOS) and stirred, tetraethylammonium hydroxide (TEAOH) is added with stirring until TEOS evaporates to give an alcohol, hydrogen Fluoride (HF) is added to the clarified solution, forming a thin paste. Finally, a suspension of dealuminized nano Beta seed crystals (20 nm) and water is added to obtain the product with a chemical composition of 0.03SnO 2 ：SiO 2 ：6TEA：15H 2 O:10HF, then crystallized at the temperature of 413K for 10 days, and then the obtained solid is filtered, washed by distilled water, dried at the temperature of 393K for 5 hours, and then roasted at the condition of 823K for 10 hours to obtain a molecular sieve sample. Wherein the dosage of TEOS is 20.81g, the dosage of TEAOH is 88.42g 4 .5H 2 The amount of O used was 1.05g, the amount of water used was 27.01g, and the amount of HF used was 20g.
Preparation of example 3
In the present production example, reference is made to "Yang X, wu L, wang Z, et al, conversion of dihydroxy to methyl lactate catalyzed by high active Sn-USY at room temperature [ J ]. Catalysis Science & Technology,2016,6 (6): 1757-1763" for the preparation of Sn-USY molecular sieves, which comprises:
mixing an H-USY molecular sieve and nitric acid, treating for 8 hours at 85 ℃, filtering and washing a sample by deionized water, and drying for 12 hours at 120 ℃ to obtain a solid sample. This solid sample was mixed with tin tetrachloride pentahydrate (SnCl) 4 .5H 2 O) for 1 hour to obtain a mixture with a chemical composition of 0.03SnO 2 ：100SiO 2 Drying the mixed liquid at 100 ℃ for 12h, and finally roasting at 550 ℃ for 3 hours to obtain a molecular sieve sample. Wherein the dosage of H-USY is 2.0g, the dosage of nitric acid is 50mL 4 .5H 2 The amount of O used was 0.6g.
Preparation of example 4
The preparation example prepares the TS-1 molecular sieve, and the specific preparation method comprises the following steps:
a tetrapropylammonium hydroxide (TPAOH, 20%) solution in an amount of about 3/4 was added to a tetraethyl orthosilicate (TEOS) solution to obtain a liquid mixture having a pH of about 13, and then a desired amount of n-butyl titanate [ Ti (OBu) ] was added dropwise to the obtained liquid mixture under vigorous stirring 4 ]Stirring for 15 min to obtain clear liquid, and slowly adding the rest TPAOH into the clear liquid, and stirring at 348-353K for about 3 hr to obtain 0.03TiO 2 ：SiO 2 :0.36TPA：35H 2 And O sol, then crystallizing for 3 days at the temperature of 443K, filtering the obtained solid, washing with distilled water, drying for 5 hours at the temperature of 373K, and then roasting for 10 hours at the condition of 823K to obtain a molecular sieve sample. Wherein the amount of TEOS is 42g, the amount of TPAOH is 73g, ti (OBu) 4 The amount of (A) was 2g, the amount of anhydrous isopropyl alcohol was 10g, and the amount of water was 68g.
Preparation of example 5
The preparation method for preparing the TS-2 molecular sieve comprises the following steps:
a certain amount of tetrabutylammonium hydroxide solution (TBAOH, 20%) was mixed with Tetraethoxysilane (TEOS), and then a desired amount of n-butyl titanate [ Ti (OBu) ] was added dropwise to the resulting transparent liquid mixture under vigorous stirring 4 ]Stirring for 30 minutes to obtain a clear liquid after hydrolysis. Finally, 2 times the amount of distilled water was added and the sol was stirred at 348-353K for 2h to remove the alcohol. The chemical composition of the sol obtained was 0.03TiO 2 ：SiO 2 :0.2TBA：20H 2 And O. And (3) crystallizing the sol at 443K for 3 days, filtering and washing the obtained crystallized product, drying for 6h under 373K, and roasting for 16h under 823K to obtain a molecular sieve sample. Wherein the amount of TEOS is 42g, the amount of TBAOH is 52g, ti (OBu) 4 The amount of (b) was 2g, the amount of anhydrous isopropyl alcohol was 10g, and the amount of water was 30g.
Preparation of example 6
The preparation method for preparing the Ti-Beta molecular sieve comprises the following steps:
a certain amount of tetraethyl orthosilicate (TEOS) was added to a solution of metered tetraethylammonium hydroxide solution (TEAOH, 20%) and hydrogen peroxide and hydrolyzed under stirring for 2h. Then weighed tetrabutyl titanate [ Ti (OBu) 4 ]Adding the anhydrous isopropanol solution into hydrolysate of ethyl orthosilicate, continuously stirring for 3h to remove alcohol, and finally obtaining the chemical composition of TiO 2 ：60SiO 2 :33TEA：400H 2 O:20H 2 O 2 The sol of (4). Finally, adding dealuminized P-type molecular sieve seed crystals and stirring vigorously (the seed crystal adding amount is that the sol is calculated by silica, and 4g of seed crystals are added into 100g of silica). After the mixture is crystallized under 413K for 14 days, the obtained slurry is filtered, washed by water, dried under 373K for 6h, and then calcined under 823K for 12h to obtain a molecular sieve sample. Wherein the amount of TEOS is 42g, the amount of TEAOH is 81g, ti (OBu) 4 The dosage of the compound is 1.16g, the dosage of the anhydrous isopropanol is 10g, and the dosage of the hydrogen peroxide is 7.5g.
Preparation of comparative example 1
The hollow titanium silicalite molecular sieve HTS prepared by the preparation comparative example is prepared by the method described in the specification example 1 of the Chinese patent CN1301599A, and the specific preparation method is as follows:
22.5 g tetraethyl orthosilicate and 7.0 g tetrapropylammonium hydroxide were mixed, 59.8 g distilled water was added, after mixing uniformly, hydrolysis was carried out at 60 ℃ for 1.0 hour under normal pressure to obtain a hydrolysis solution of tetraethyl orthosilicate, a solution consisting of 1.1 g tetrabutyl titanate and 5.0 g anhydrous isopropyl alcohol was slowly added with vigorous stirring, and the resulting mixture was stirred at 75 ℃ for 3 hours to obtain a clear transparent colloid. Placing the colloid in a stainless steel sealed reaction kettle, and standing at a constant temperature of 170 ℃ and a self-generated pressure for 6 days to obtain a mixture of crystallized products; the mixture was filtered, washed with water to pH 6-8, and dried at 110 ℃ for 60 minutes to give raw, unfired TS-1 powder. And roasting the TS-1 raw powder for 4 hours at 550 ℃ in an air atmosphere to obtain the TS-1 molecular sieve.
And (2) uniformly mixing the obtained TS-1 molecular sieve according to the proportion of the molecular sieve (g) to sulfuric acid (mol) to water (mol) = 100: 0.15: 150, reacting for 5.0 hours at 90 ℃, and then filtering, washing and drying according to a conventional method to obtain the acid-treated TS-1 molecular sieve.
The TS-1 molecular sieve treated by the acid is uniformly mixed according to the proportion of the molecular sieve (g), the triethanolamine (mol), the tetrapropylammonium hydroxide (mol) and the water (mol) = 100: 0.20: 0.15: 180, the mixture is put into a stainless steel sealed reaction kettle, the stainless steel sealed reaction kettle is placed for 0.5 day at the constant temperature of 190 ℃ and the autogenous pressure, and after cooling and pressure relief, the HTS molecular sieve is obtained by filtering, washing and drying according to a conventional method and is roasted for 3 hours at 550 ℃ in an air atmosphere.
The HTS molecular sieve has a hollow structure with the radial length of 5-100 nanometers, and the benzene adsorption quantity measured by a static adsorption method under the conditions of 25 ℃, P/P0=0.10 and 1 hour of adsorption time is 85 mg/g molecular sieve; the adsorption isotherm and the desorption isotherm of the low-temperature nitrogen adsorption determined according to the standard method of astm d4222-98 show that there is a hysteresis loop between the adsorption isotherm and the desorption isotherm of the low-temperature nitrogen adsorption.
Preparation of comparative example 2
The preparation method of the tin-loaded titanium silicalite Sn/TS-1 adopted in the preparation comparative example is as follows:
the pentahydrate stannic chloride (SnCl) 4 .5H 2 O) and TS-1 molecular sieve (prepared by the method of the comparative preparation example 1) are directly and mechanically mixed and then are roasted for 5 hours at 550 ℃ to obtain the molecular sieve with the chemical composition of 0.03TiO 2 :SiO 2 :0.03SnO 2 The molecular sieve of (1). Wherein the dosage of TS-1 is 2g 4 .5H 2 The amount of O used was 0.76g.
The examples and comparative examples illustrate the preparation of methylglyoxal by the catalytic oxidation of sugars using different catalysts.
Example 1
0.15g of the tin-silicon molecular sieve Sn-MFI prepared in preparation example 1 and 0.15g of the titanium-silicon molecular sieve TS-1 prepared in preparation example 4 are weighed out as catalysts and filled in a 100mL polytetrafluoroethylene lining, and then 8g of methanol and 0.1g of glucose are added in sequence. The polytetrafluoroethylene lining is placed in a stainless steel reaction kettle for sealing and placed in a homogeneous reactor for starting reaction. The reaction temperature is controlled at about 120 ℃ and the reaction is carried out for 17 hours. The specific reaction results are shown in Table 1.
Comparative example 1
0.3g of the Sn-MFI catalyst of the tin-silicon molecular sieve prepared in preparation example 1 was weighed out and packed in a 100mL polytetrafluoroethylene liner, and 8g of methanol and 0.1g of glucose were sequentially added. The polytetrafluoroethylene lining is placed in a stainless steel reaction kettle for sealing and placed in a homogeneous reactor for starting reaction. The reaction temperature is controlled at about 120 ℃ and the reaction is carried out for 17 hours. The specific reaction results are shown in Table 1.
Comparative example 2
0.3g of the titanium silicalite TS-1 catalyst prepared in preparation example 4 was weighed out and loaded into a 100mL polytetrafluoroethylene liner, and then 8g of methanol and 0.1g of glucose were sequentially added. The polytetrafluoroethylene lining is placed in a stainless steel reaction kettle for sealing and placed in a homogeneous reactor for starting reaction. The reaction temperature is controlled to be about 120 ℃ and the reaction is carried out for 17 hours. The specific reaction results are shown in Table 1.
Comparative example 3
0.3g of the hollow titanium silicalite HTS catalyst prepared in comparative example 1 was weighed and charged in a 100mL polytetrafluoroethylene inner liner, and then 8g of methanol and 0.1g of glucose were sequentially added. The polytetrafluoroethylene lining is placed in a stainless steel reaction kettle for sealing and placed in a homogeneous reactor for starting reaction. The reaction temperature is controlled to be about 120 ℃ and the reaction is carried out for 17 hours. The specific reaction results are shown in Table 1.
Comparative example 4
0.3g of the tin-loaded titanium silicalite Sn/TS-1 catalyst prepared in the preparation comparative example 2 is weighed and filled in a 100mL polytetrafluoroethylene lining, and then 8g of methanol and 0.1g of glucose are sequentially added. The polytetrafluoroethylene lining is placed in a stainless steel reaction kettle for sealing and placed in a homogeneous reactor for starting reaction. The reaction temperature is controlled to be about 120 ℃ and the reaction is carried out for 17 hours. The specific reaction results are shown in Table 1.
Comparative example 5
The same as example 1 except that: the reaction temperature was 90 ℃ and the reaction time was 6 hours. The specific reaction results are shown in Table 1.
Comparative example 6
Substantially the same as in example 1, except that: the reaction temperature was 160 ℃ and the reaction time was 55 hours. The specific reaction results are shown in Table 1.
Example 2
0.15g of the Sn-Beta molecular sieve prepared in preparation example 2 and 0.15g of the TS-1 molecular sieve prepared in preparation example 4 are weighed as catalysts and filled in a 100mL polytetrafluoroethylene lining, and then 8g of ethanol and 0.1g of fructose are sequentially added. The polytetrafluoroethylene lining is placed in a stainless steel reaction kettle for sealing and placed in a homogeneous reactor for starting reaction. The reaction temperature was controlled at about 140 ℃ and the reaction was carried out for 17 hours. The specific reaction results are shown in Table 1.
Example 3
0.15g of the Sn-USY molecular sieve prepared in preparation example 3 and 0.15g of the TS-1 molecular sieve prepared in preparation example 4 are weighed as catalysts and filled in a 100mL polytetrafluoroethylene lining, and then 8g of n-butanol and 0.1g of xylose are sequentially added. The polytetrafluoroethylene lining is placed in a stainless steel reaction kettle for sealing and placed in a homogeneous reactor for starting reaction. The reaction temperature was controlled at about 140 ℃ and the reaction was carried out for 17 hours. The specific reaction results are shown in Table 1.
Example 4
0.15g of the tin-silicon molecular sieve Sn-MFI prepared in preparation example 1 and 0.15g of the titanium-silicon molecular sieve TS-2 prepared in preparation example 5 were weighed out as catalysts and charged into a 100mL polytetrafluoroethylene liner, and 8g of butanediol and 0.1g of mannose were added in this order. The polytetrafluoroethylene lining is placed in a stainless steel reaction kettle for sealing and placed in a homogeneous reactor for starting reaction. The reaction temperature was controlled at about 140 ℃ and the reaction was carried out for 17 hours. The specific reaction results are shown in Table 1.
Example 5
0.15g of the Sn-MFI molecular sieve prepared in preparation example 1 and 0.15g of the Ti-Beta molecular sieve prepared in preparation example 6 were weighed out as catalysts and placed in a 100mL polytetrafluoroethylene liner, and 8g of pentanol and 0.1g of mannose were added in this order. The polytetrafluoroethylene lining is placed in a stainless steel reaction kettle for sealing and placed in a homogeneous reactor for starting reaction. The reaction temperature is controlled to be about 110 ℃ and the reaction is carried out for 17 hours. The specific reaction results are shown in Table 1.
Example 6
0.5g of the tin-silicon molecular sieve Sn-MFI prepared in preparation example 1 and 0.5g of the titanium-silicon molecular sieve TS-1 prepared in preparation example 4 are weighed as catalysts and filled in a 100mL polytetrafluoroethylene lining, and then 8g of methanol and 0.2g of glucose are added in sequence. The polytetrafluoroethylene lining is placed in a stainless steel reaction kettle for sealing and placed in a homogeneous reactor for starting reaction. The reaction temperature is controlled to be about 120 ℃, and the reaction is carried out for 20 hours. The specific reaction results are shown in Table 1.
Example 7
0.01g of the tin-silicon molecular sieve Sn-MFI prepared in preparation example 1 and 0.03g of the titanium-silicon molecular sieve TS-1 prepared in preparation example 4 are weighed as catalysts and filled in a 100mL polytetrafluoroethylene lining, and then 8g of methanol and 0.2g of fructose are added in sequence. The polytetrafluoroethylene lining is placed in a stainless steel reaction kettle for sealing and placed in a homogeneous reactor for starting reaction. The reaction temperature is controlled at about 140 ℃ and the reaction is carried out for 18 hours. The specific reaction results are shown in Table 1.
Example 8
0.1g of the tin-silicon molecular sieve Sn-MFI prepared in preparation example 1 and 0.1g of the titanium-silicon molecular sieve TS-1 prepared in preparation example 4 are weighed out as catalysts and filled in a 100mL polytetrafluoroethylene lining, and 8g of ethanol and 0.7g of glucose are added in sequence. The polytetrafluoroethylene lining is placed in a stainless steel reaction kettle for sealing and placed in a homogeneous reactor for starting reaction. The reaction temperature was controlled at about 130 ℃ and the reaction was carried out for 14 hours. The specific reaction results are shown in Table 1.
Example 9
The same as example 1 except that: the molar ratio of sugar to alcohol is 1:50, the reaction temperature is 100 ℃, the reaction time is 10 hours, the weight ratio of the sugar to the mixture of the titanium silicalite molecular sieve and the tin silicalite molecular sieve is 1. The specific reaction results are shown in Table 1.
Example 10
Substantially the same as in example 1, except that: the molar ratio of sugar to alcohol is 1:600, the reaction temperature is 145 ℃, the reaction time is 50 hours, the weight ratio of sugar to the mixture of the titanium-silicon molecular sieve and the tin-silicon molecular sieve is 1. The specific reaction results are shown in Table 1.
As can be seen from the results of the above examples and comparative examples, the method of the present invention for preparing methylglyoxal has the advantages of simple operation process, mild reaction conditions, high raw material conversion rate and methylglyoxal selectivity; especially when the catalyst is a mixture of a titanium silicalite molecular sieve and a tin silicalite molecular sieve, and the molar ratio of sugar to alcohol is 1: (50-600), the reaction temperature is more than 100 ℃ and less than 150 ℃, the reaction time is 10-50h, and when the reaction pressure is 0.1-6.0MPa, the weight ratio of the sugar to the mixture of the titanium silicalite molecular sieve and the tin silicalite molecular sieve is 1: (0.1-6), and further preferably the molar ratio of sugar to alcohol is 1: (100-500), the weight ratio of sugar to the mixture of titanium silicalite molecular sieves and tin silicalite molecular sieves is 1: (0.2-3), the reaction temperature is 110-140 ℃, the reaction time is 12-40h, and the reaction pressure is 0.1-4MPa, which is more beneficial to improving the conversion rate of sugar and the yield of methylglyoxal.
The preferred embodiments of the present invention have been described in detail, however, the present invention is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present invention within the technical idea of the present invention, and these simple modifications are within the protective scope of the present invention.
It should be noted that the various technical features described in the above embodiments can be combined in any suitable manner without contradiction, and the invention is not described in any way for the possible combinations in order to avoid unnecessary repetition.
In addition, any combination of the various embodiments of the present invention is also possible, and the same should be considered as the content of the present invention as long as it does not depart from the gist of the present invention.
TABLE 1
Numbering Sugar conversion/% Methylglyoxal selectivity/%)
Example 1 79 79
Example 2 75 75
Example 3 80 77
Example 4 78 76
Example 5 79 72
Example 6 75 74
Example 7 76 76
Example 8 78 75
Example 9 75 70
Example 10 80 70
Comparative example 1 57 48
Comparative example 2 42 38
Comparative example 3 44 30
Comparative example 4 30 13
Comparative example 5 21 10
Comparative example 6 80 17

Claims (7)

1. A method of preparing methylglyoxal, the method comprising:
contacting sugar with a catalyst in a reactor in the presence of alcohol and carrying out reaction to obtain a product containing methylglyoxal; wherein the molar ratio of sugar to alcohol is 1: (50-600), the reaction temperature is more than 100 ℃ and less than 150 ℃, the reaction time is 10-50h, the catalyst contains a mixture of titanium silicalite and tin silicalite, and the weight ratio of sugar to the mixture of titanium silicalite and tin silicalite on a dry basis is 1: (0.1-6);
the mixing weight ratio of the titanium silicalite molecular sieve to the tin silicalite molecular sieve in the catalyst is 1: (0.1-10), wherein the tin-silicon molecular sieve is selected from Sn-MFI molecular sieves, and the titanium-silicon molecular sieve is selected from TS-1 molecular sieves.
2. The process of claim 1, wherein the titanium silicalite molecular sieve has a titania to silica molar ratio of (0.01-10): 100;
the molar ratio of tin dioxide to silicon dioxide in the tin-silicon molecular sieve is (0.01-10): 100.
3. the process of claim 2, wherein the titanium silicalite molecular sieve has a molar ratio of titania to silica of (0.05-5): 100;
the molar ratio of tin dioxide to silicon dioxide in the tin-silicon molecular sieve is (0.05-5): 100.
4. The method according to claim 1, wherein the sugar is one or more selected from the group consisting of a pentose, a hexose, and a disaccharide, the pentose is xylose, the hexose is one or more selected from the group consisting of glucose, fructose, and mannose, and the disaccharide is sucrose;
the alcohol is one or more selected from monohydric alcohol, dihydric alcohol and polyhydric alcohol containing more than three hydroxyl groups; the monohydric alcohol is selected from one or more of methanol, ethanol, propanol, n-butanol, isobutanol and pentanol, the dihydric alcohol is selected from one or more of ethylene glycol, propylene glycol, butanediol and hexanediol, and the polyhydric alcohol is selected from one or more of glycerol, trimethylolethane, pentaerythritol, xylitol and sorbitol.
5. The method of claim 1, wherein the molar ratio of sugar to alcohol is 1: (100-500), the weight ratio of sugar to the mixture of titanium silicalite molecular sieves and tin silicalite molecular sieves is 1: (0.2-3), the reaction temperature is 110-140 ℃, the reaction time is 12-40h, and the reaction pressure is 0.1-6MPa.
6. The process according to claim 5, wherein the reaction pressure is 0.1-4MPa.
7. The process of claim 1, wherein the reactor is a tank reactor, a fixed bed reactor, a moving bed, a suspended bed, or a slurry bed reactor.
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