CN111253238B - Method for preparing lactic acid - Google Patents
Method for preparing lactic acid Download PDFInfo
- Publication number
- CN111253238B CN111253238B CN201811456811.7A CN201811456811A CN111253238B CN 111253238 B CN111253238 B CN 111253238B CN 201811456811 A CN201811456811 A CN 201811456811A CN 111253238 B CN111253238 B CN 111253238B
- Authority
- CN
- China
- Prior art keywords
- molecular sieve
- tin
- silicon
- titanium
- silicon molecular
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
-
- 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
- B01J29/89—Silicates, aluminosilicates or borosilicates of titanium, zirconium or hafnium
-
- 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
- B01J2229/00—Aspects of molecular sieve catalysts not covered by B01J29/00
- B01J2229/10—After treatment, characterised by the effect to be obtained
- B01J2229/18—After treatment, characterised by the effect to be obtained to introduce other elements into or onto the molecular sieve itself
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Materials Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Catalysts (AREA)
Abstract
The present invention relates to a method for preparing lactic acid, comprising: contacting methylglyoxal and water with a catalyst in a reactor and reacting to obtain a product containing lactic acid; wherein the molar ratio of methylglyoxal to water is 1: (40-350), the reaction temperature is 30-180 ℃, the reaction time is 1-10h, the catalyst contains a mixture of a titanium-silicon molecular sieve and a tin-silicon molecular sieve, and the weight ratio of methylglyoxal to the mixture of the titanium-silicon molecular sieve and the tin-silicon molecular sieve is 1: (0.1-6). The method of the present invention has high methylglyoxal conversion and lactic acid yield.
Description
Technical Field
The present invention relates to a method for preparing lactic acid.
Background
Lactic acid (2-hydroxypropionic acid, scientific name) is a compound that functions in a variety of biochemical processes, and has the molecular formula C 3 H 6 O 3 . It is a carboxylic acid containing a hydroxyl group and is therefore an alpha-hydroxy acid. Its carboxyl group in aqueous solution releases a proton to produce lactate ion. Lactate dehydrogenase converts pyruvate to L-lactate during fermentation. Lactic acid is produced continuously during normal metabolism and exercise, but its concentration does not generally rise. Lactic acid is a colorless liquid, and the industrial product is a colorless to pale yellow liquid. The natural plant extract is odorless, has hygroscopicity, has a relative density of 1.200, a melting point of 18 ℃, a boiling point of 122 ℃ and a flash point of more than 110 ℃, is miscible with ethanol, ether, water and glycerin, is insoluble in chloroform, carbon disulfide and petroleum ether, and is widely applied to the food industry, the pharmaceutical industry, the cosmetic industry and the agricultural and livestock industry.
The traditional lactic acid production method mainly adopts a sugar fermentation method and a chemical synthesis method. The fermentation method uses saccharides as raw materials, and the pH value of a fermentation system needs to be maintained within the range of 5.5-6.5, but the pH value is gradually reduced along with the continuous generation of lactic acid, so that calcium oxide or calcium carbonate needs to be continuously added in the reaction process to balance the pH value of the system. The generated calcium lactate is treated by sulfuric acid to obtain crude lactic acid, and simultaneously, a large amount of waste salt (calcium sulfate) is generated. However, crude lactic acid is difficult to separate and needs to be reacted with alcohol to produce lactate with a relatively low boiling point, and then subjected to distillation separation and hydrolysis reaction to obtain high-purity lactic acid. The reaction route of the process is long, the production cost is high, and a large amount of solid waste residue is generated, so that the large-scale production and application of the lactic acid cannot be realized at present. The commonly used chemical synthesis method is a lactonitrile method and a propionic acid method, the lactonitrile method uses acetaldehyde and hypertoxic hydrocyanic acid as reaction raw materials, and concentrated sulfuric acid is a catalyst, so that the pollution in the production process is serious, and potential safety hazards exist. The propionic acid method uses toxic chlorine as a raw material, has high requirements on operation safety and tightness, and is easy to cause pollution to the atmospheric environment.
Disclosure of Invention
The object of the present invention is to provide a process for the preparation of lactic acid with a high conversion of methylglyoxal and a high yield of lactic acid.
In order to achieve the above object, the present invention provides a method for preparing lactic acid, comprising:
the method comprises the following steps of (1) enabling methylglyoxal and water to contact with a catalyst in a reactor and reacting to obtain a product containing lactic acid; wherein the molar ratio of methylglyoxal to water is 1: (40-350), the reaction temperature is 30-180 ℃, the reaction time is 1-10h, the catalyst contains a mixture of a titanium-silicon molecular sieve and a tin-silicon molecular sieve, and the weight ratio of methylglyoxal to the mixture of the titanium-silicon molecular sieve and the tin-silicon molecular sieve 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 mixing 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.
Optionally, 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 molar ratio of methylglyoxal to water is 1: (60-200), wherein the weight ratio of the methylglyoxal to the mixture of titanium silicalite molecular sieves and tin silicalite molecular sieves is 1: (0.2-3), the reaction temperature is 40-120 ℃, the reaction time is 2-8h, the reaction pressure is 0.1-3MPa, and the reaction pressure is preferably 0.1-2MPa.
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 titanium atoms of the titanium-silicon molecular sieve and the framework tin atoms of the tin-silicon molecular sieve are cooperated to catalyze the methylglyoxal to generate the lactic acid, thereby improving the reaction efficiency. Compared with the prior art, higher methylglyoxal conversion rate and lactic acid yield can be obtained in a short time under mild reaction conditions, the subsequent separation energy consumption of products is lower, the process is safer and more efficient, and the method 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.
Drawings
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 methylglyoxal to lactic acid 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 preferred embodiment of the 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 present invention provides a method for preparing lactic acid, comprising: contacting methylglyoxal and water with a catalyst in a reactor and reacting to obtain a product containing lactic acid; wherein the molar ratio of the methylglyoxal to the water is 1: (40-350), the reaction temperature is 30-180 ℃, the reaction time is 1-10h, the catalyst contains a mixture of a titanium-silicon molecular sieve and a tin-silicon molecular sieve, and the weight ratio of methylglyoxal to the mixture of the titanium-silicon molecular sieve and the tin-silicon molecular sieve 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. Specific preparation methods of tin-silicon molecular sieves can refer to chinese patents CN104549549A, CN107162014A, CN105271294A, CN103964461A, CN105314649A, CN104557629A, CN104557632A, CN103204806A, CN103204830A, CN103204775A, 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. Specific preparation methods of the titanium-silicon molecular sieves can refer to chinese patents CN107879357A, CN107879354A, CN107879356A, CN107879355A, CN107986293A, CN107986294A, CN108002404A, CN107539999A, CN107537559A, CN107539998A, CN103182323A, CN103183355A, CN106964400A, CN106904633A, CN107986292A, CN103182320A, CN103182322A, CN103183356A, CN101439300A, CN106145151A, CN 106840347A, CN106145148A, CN 145149A, CN106145147A and CN107840344A, preferably, the titanium-silicon molecular sieves are at least one selected from MFI type titanium-silicon molecular sieves, MEL type titanium-silicon molecular sieves and BEA type titanium-silicon molecular sieves. Further preferably, the titanium silicalite molecular sieve is an MFI-type titanium silicalite molecular sieve. The MFI-type titanium silicalite is commercially available or can be prepared according to literature procedures (studie on the synthesis of titanium silicalite, TS-1 Zeolite, 1992,12 (8), 943-50).
According to the invention, the skeleton titanium atoms of the titanium silicalite molecular sieve and the skeleton tin atoms of the tin silicalite molecular sieve are used for cooperatively catalyzing methylglyoxal to generate lactic acid, the titanium silicalite molecular sieve and the tin silicalite molecular sieve in the catalyst can be mixed in any proportion, preferably, the mixing weight ratio of the titanium silicalite molecular sieve to the tin silicalite 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 even more preferably, the mixing weight ratio of the titanium-silicon molecular sieves to the tin-silicon 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 molar ratio of titanium dioxide to silicon dioxide in the titanium silicalite molecular sieve may be (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 invention, the molar ratio of methylglyoxal to water is preferably 1: (60-200), the weight ratio of methylglyoxal to the mixture of titanium silicalite and tin silicalite on a dry basis is preferably 1: (0.2-3), the reaction temperature is preferably 40-120 ℃, the reaction time is preferably 2-8h, the reaction pressure (absolute pressure) can be 0.1-3MPa, and the reaction pressure is preferably 0.1-2MPa.
The reaction according to the present invention may be carried out in a conventional catalytic reactor according to the present invention, 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 a three-neck flask, or in a suitable other reactor such as a fixed bed, a moving bed, a suspended bed, etc., preferably in a tank reactor, a fixed bed reactor, a moving bed, a suspended bed, or a slurry bed reactor, the specific operation of which is well known to those skilled in the art, and the detailed description of the present invention will be omitted.
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 lactic acid-containing product 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, filtration, centrifugation, evaporation, membrane separation, or the like, or the catalyst can be molded and loaded into a fixed bed reactor, and the catalyst can be recovered after the reaction is completed.
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 each component in the activity evaluation system, the analysis result is quantified by an internal standard method, and the internal standard substance is naphthalene. Wherein, the chromatographic analysis conditions 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 ℃.
In each of the examples and comparative examples:
methylglyoxal conversion% = (moles of methylglyoxal in raw material-moles of methylglyoxal in product)/moles of methylglyoxal in raw material x 100%;
lactic acid selectivity% = mole of lactic acid in product/(mole of methylglyoxal in raw material-mole of methylglyoxal in product) × 100%;
the yield of lactic acid is% = mole number of lactic acid in product/mole number of methylglyoxal in raw material x 100%, namely the yield of lactic acid is% = selectivity of lactic acid x conversion rate of methylglyoxal.
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:
the pentahydrate stannic chloride (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) dissolving in water, adding tetraethyl orthosilicate (TEOS) into the water solution, stirring, adding tetraethyl ammonium hydroxide (TEAOH) while stirring, stirring until TEOS is evaporated to obtain alcohol, and adding Hydrogen Fluoride (HF) into the clear solution to form a paste thin layer. Finally adding a suspension of dealuminized nano Beta seed crystal (20 nm) and water to obtain the product with the 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 preparation example, the Sn-USY molecular sieve is prepared by the method of "Yang X, wu L, wang Z, et al. Conversion of dihydroxy catalyst to methyl lactate catalyzed by high activity active Sn-USY at room temperature [ J ]. Catalysis Science & Technology,2016,6 (6): 1757-1763", and the Sn-USY molecular sieve is prepared by the method of:
mixing the H-USY molecular sieve with nitric acid, treating at 85 ℃ for 8H, filtering and washing a sample with deionized water, and drying at 120 ℃ for 12H to obtain a solid sample. This solid sample was mixed with tin tetrachloride pentahydrate (SnCl) 4 .5H 2 O) for 1h to obtain a chemical composition of 0.03SnO 2 ：100SiO 2 The mixed liquid is dried for 12 hours at 100 ℃, and finally roasted for 3 hours at 550 ℃ 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 the anhydrous isopropanol solution for 15 minutes to obtain a clear liquid, and finally slowly adding the rest TPAOH into the clear liquid, and stirring the mixture for about 3 hours at 348-353K to obtain the anhydrous isopropanol solution with the chemical composition of 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 tetraethyl orthosilicate (TEOS), and then the desired amount of n-butyl titanate [ Ti (OBu) ] was added dropwise to the resulting clear liquid mixture with vigorous stirring 4 ]Stirring for 30 minutes to obtain a clear liquid after hydrolysis. Finally, 2 times the amount of distilled water required 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 6 hours under 373K, and roasting for 16 hours 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 (A) was 2g, the amount of anhydrous isopropyl alcohol was 10g, and the amount of water was 30g.
Preparation of example 6
The preparation embodiment for preparing the Ti-Beta molecular sieve comprises the following specific preparation methods:
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 the hydrolysate of tetraethoxysilane, continuously stirring for 3 hours to remove alcohol, and finally obtaining the product with 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 roasted 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 (3) uniformly mixing the obtained TS-1 molecular sieve according to the proportion of 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:
adding tin tetrachloride pentahydrate (SnCl) 4 .5H 2 O) and TS-1 molecular sieve (prepared by the method of 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 lactic acid using a different catalyst to catalyze methylglyoxal.
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 as catalysts and placed in a 15mL glass reaction tube, then a magnetic stirrer, 8g of water and 0.1g of methylglyoxal are sequentially added, and a cover of the glass reaction tube is screwed on. And (3) placing the glass reaction tube in an oil bath, placing the glass reaction tube on a temperature control magnetic stirrer, starting the magnetic stirrer and a heating device, and starting the reaction. The reaction temperature is controlled at about 60 ℃ and the reaction is carried out for 7 hours. The specific reaction results are shown in Table 1.
Comparative example 1
0.3g of the Sn-Si molecular sieve Sn-MFI catalyst prepared in preparation example 1 is weighed and loaded in a 15mL glass reaction tube, then a magnetic stirrer, 8g of water and 0.1g of methylglyoxal are sequentially added, and the cover of the glass reaction tube is screwed on. And (3) placing the glass reaction tube in an oil bath, placing the glass reaction tube on a temperature control magnetic stirrer, starting the magnetic stirrer and a heating device, and starting the reaction. The reaction temperature is controlled to be about 60 ℃ and the reaction is carried out for 7 hours. The specific reaction results are shown in Table 1.
Comparative example 2
Weighing 0.3g of the titanium silicalite TS-1 catalyst prepared in preparation example 4, filling the catalyst into a 15mL glass reaction tube, sequentially adding a magnetic stirrer, 8g of water and 0.1g of methylglyoxal, and screwing a cover of the glass reaction tube. And putting the glass reaction tube in an oil bath, putting the glass reaction tube on a temperature control magnetic stirrer, and starting the magnetic stirrer and a heating device to start reaction. The reaction temperature is controlled to be about 60 ℃ and the reaction is carried out for 7 hours. The specific reaction results are shown in Table 1.
Comparative example 3
0.3g of the hollow titanium silicalite molecular sieve HTS catalyst prepared in the preparation comparative example 1 is weighed and placed in a 15mL glass reaction tube, then a magnetic stirrer, 8g of water and 0.1g of pyruvaldehyde are sequentially added, and the cover of the glass reaction tube is screwed on. And (3) placing the glass reaction tube in an oil bath, placing the glass reaction tube on a temperature control magnetic stirrer, starting the magnetic stirrer and a heating device, and starting the reaction. The reaction temperature is controlled at about 60 ℃ and the reaction is carried out for 7 hours. The specific reaction results are shown in Table 1.
Comparative example 4
0.3g of the Sn/TS-1 catalyst of the Ti-Si molecular sieve prepared in comparative example 2 is weighed and loaded in a 15mL glass reaction tube, then a magnetic stirrer, 8g of water and 0.1g of pyruvaldehyde are added in sequence, and the cover of the glass reaction tube is screwed on. And putting the glass reaction tube in an oil bath, putting the glass reaction tube on a temperature control magnetic stirrer, and starting the magnetic stirrer and a heating device to start reaction. The reaction temperature is controlled to be about 60 ℃ and the reaction is carried out for 7 hours. The specific reaction results are shown in Table 1.
Comparative example 5
The same as example 1 except that: the reaction temperature was 10 ℃ and the reaction time was 0.5 hour. The specific reaction results are shown in Table 1.
Comparative example 6
Substantially the same as in example 1, except that: the reaction temperature is 200 ℃, the reaction time is 12 hours, the reaction raw materials and the catalyst are filled in a polytetrafluoroethylene lining, then the polytetrafluoroethylene lining is placed in a stainless steel reaction kettle for sealing, and the reaction is carried out in a homogeneous reactor. The specific reaction results are shown in Table 1.
Example 2
0.15g of the tin-silicon molecular sieve Sn-Beta prepared in preparation example 2 and 0.15g of the titanium-silicon molecular sieve TS-1 prepared in preparation example 4 are weighed as catalysts and filled in a 15mL glass reaction tube, then a magnetic stirrer, 8g of water and 0.1g of pyruvaldehyde are sequentially added, and the cover of the glass reaction tube is screwed on. And (3) placing the glass reaction tube in an oil bath, placing the glass reaction tube on a temperature control magnetic stirrer, starting the magnetic stirrer and a heating device, and starting the reaction. The reaction temperature is controlled to be about 60 ℃ and the reaction is carried out for 7 hours. The specific reaction results are shown in Table 1.
Example 3
0.15g of the tin-silicon molecular sieve Sn-USY prepared in preparation example 3 and 0.15g of the titanium-silicon molecular sieve TS-1 prepared in preparation example 4 are weighed as catalysts and put into a 15mL glass reaction tube, then a magnetic stirrer, 8g of water and 0.1g of pyruvaldehyde are added in sequence, and the cover of the glass reaction tube is screwed on. And putting the glass reaction tube in an oil bath, putting the glass reaction tube on a temperature control magnetic stirrer, and starting the magnetic stirrer and a heating device to start reaction. The reaction temperature is controlled at about 60 ℃ and the reaction is carried out for 7 hours. The specific reaction results are shown in Table 1.
Example 4
0.15g of the 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 are weighed as catalysts and filled in a 15mL glass reaction tube, then a magnetic stirrer, 8g of water and 0.1g of methylglyoxal are sequentially added, and a cover of the glass reaction tube is screwed on. And (3) placing the glass reaction tube in an oil bath, placing the glass reaction tube on a temperature control magnetic stirrer, starting the magnetic stirrer and a heating device, and starting the reaction. The reaction temperature is controlled at about 60 ℃ and the reaction is carried out for 7 hours. The specific reaction results are shown in Table 1.
Example 5
0.15g of the tin-silicon molecular sieve Sn-MFI prepared in preparation example 1 and 0.15g of the titanium-silicon molecular sieve Ti-Beta prepared in preparation example 6 are weighed as catalysts and placed in a 15mL glass reaction tube, then a magnetic stirrer, 8g of water and 0.1g of methylglyoxal are sequentially added, and a cover of the glass reaction tube is screwed on. And putting the glass reaction tube in an oil bath, putting the glass reaction tube on a temperature control magnetic stirrer, and starting the magnetic stirrer and a heating device to start reaction. The reaction temperature is controlled to be about 60 ℃ and the reaction is carried out for 7 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 placed in a 15mL glass reaction tube, then a magnetic stirrer, 8g of water and 0.2g of methylglyoxal are sequentially added, and a cover of the glass reaction tube is screwed on. And putting the glass reaction tube in an oil bath, putting the glass reaction tube on a temperature control magnetic stirrer, and starting the magnetic stirrer and a heating device to start reaction. The reaction temperature is controlled at about 30 ℃ and the reaction is carried out for 10 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 placed in a 15mL glass reaction tube, then a magnetic stirrer, 8g of water and 0.2g of methylglyoxal are sequentially added, and a cover of the glass reaction tube is screwed on. And putting the glass reaction tube in an oil bath, putting the glass reaction tube on a temperature control magnetic stirrer, and starting the magnetic stirrer and a heating device to start reaction. The reaction temperature is controlled at about 70 ℃ and the reaction is carried out for 8 hours.
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 as catalysts and placed in a 15mL glass reaction tube, then a magnetic stirrer, 8g of water and 0.7g of methylglyoxal are sequentially added, and a cover of the glass reaction tube is screwed on. And putting the glass reaction tube in an oil bath, putting the glass reaction tube on a temperature control magnetic stirrer, and starting the magnetic stirrer and a heating device to start reaction. The reaction temperature is controlled to be about 50 ℃ and the reaction is carried out for 4 hours. The specific reaction results are shown in Table 1.
Example 9
The same as example 1 except that: the molar ratio of methylglyoxal to water is 1:40, the reaction temperature is 30 ℃, the reaction time is 1 hour, the weight ratio of the methylglyoxal 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.
Example 10
Substantially the same as in example 1, except that: the molar ratio of methylglyoxal to water is 1:350, the reaction temperature is 180 ℃, the reaction time is 10 hours, the weight ratio of the methylglyoxal 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.
As can be seen from the results of the above examples and comparative examples, the method of the present invention for preparing lactic acid has the advantages of simple operation process, mild reaction conditions, high conversion rate of raw materials and high selectivity of lactic acid; especially when the catalyst is a mechanical mixture of tin-silicon molecular sieve and titanium-silicon molecular sieve, the molar ratio of the methylglyoxal to the water is preferably 1: (40-350), the reaction temperature is 30-180 ℃, the reaction time is 1-10h, and the reaction pressure is 0.1-3.0MPa, and the molar ratio of the methylglyoxal to the water is further preferably 1: (60-200), the reaction temperature is 40-120 ℃, the reaction time is 2-8h, and the reaction pressure is 0.1-2.0MPa, which is more beneficial to improving the conversion rate of the methylglyoxal and the yield of the lactic acid.
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 all within the protection scope of the present invention.
It should be noted that, in the above embodiments, the various features described in the above embodiments may be combined in any suitable manner, and in order to avoid unnecessary repetition, the present invention does not separately describe various possible combinations.
In addition, any combination of the various embodiments of the present invention can be made, and the same should be considered as the content of the present invention as long as the idea of the present invention is not violated.
TABLE 1
| Numbering | Methylglyoxal conversion/%) | Lactic acid selectivity/%) |
| Example 1 | 96 | 95 |
| Example 2 | 93 | 95 |
| Example 3 | 93 | 94 |
| Example 4 | 92 | 94 |
| Example 5 | 94 | 93 |
| Example 6 | 86 | 88 |
| Example 7 | 85 | 86 |
| Example 8 | 85 | 84 |
| Example 9 | 83 | 82 |
| Example 10 | 95 | 84 |
| Comparative example 1 | 81 | 76 |
| Comparative example 2 | 50 | 23 |
| Comparative example 3 | 57 | 28 |
| Comparative example 4 | 68 | 63 |
| Comparative example 5 | 13 | 14 |
| Comparative example 6 | 91 | 72 |
Claims (10)
1. A method of producing lactic acid, the method comprising:
the method comprises the following steps of (1) enabling methylglyoxal and water to contact with a catalyst in a reactor and reacting to obtain a product containing lactic acid; wherein the molar ratio of the methylglyoxal to the water is 1: (200-350), the reaction temperature is 40-120 ℃, the reaction time is 1-10h, the catalyst contains a mixture of a titanium-silicon molecular sieve and a tin-silicon molecular sieve, and the weight ratio of methylglyoxal to the mixture of the titanium-silicon molecular sieve and the tin-silicon molecular sieve on a dry basis is 1: (0.1-6); the mixing weight ratio of the titanium-silicon molecular sieve to the tin-silicon molecular sieve in the catalyst is 1: (0.1-10), 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 and an FAU type tin-silicon molecular sieve, and the titanium-silicon molecular sieve is selected from one or more of an MFI type titanium-silicon molecular sieve, an MEL type titanium-silicon molecular sieve and a BEA type titanium-silicon molecular sieve.
2. The process of claim 1, wherein the tin-silicon molecular sieves are selected from one or more of Sn-MFI molecular sieves, sn-MEL molecular sieves, sn-Beta molecular sieves, and Sn-USY molecular sieves.
3. The process of claim 1, wherein the titanium silicalite molecular sieves are selected from one or more of the group consisting of TS-1 molecular sieves, TS-2 molecular sieves, and Ti-Beta molecular sieves.
4. The process of claim 1, wherein the titanium silicalite molecular sieve has a titania to silica molar ratio of (0.01-10): 100.
5. the process of claim 4, wherein the titanium silicalite molecular sieve has a titania to silica molar ratio of (0.05-5): 100.
6. the process of claim 1, wherein the tin-silicon molecular sieve has a molar ratio of tin dioxide to silicon dioxide of (0.01-10): 100.
7. the process of claim 6, wherein the tin-silicon molecular sieve has a molar ratio of tin dioxide to silicon dioxide of (0.05-5): 100.
8. the method of claim 1, wherein the weight ratio of methylglyoxal to the mixture of titanium silicalite and tin silicalite molecular sieves is 1: (0.2-3), the reaction time is 2-8h, and the reaction pressure is 0.1-3MPa.
9. The process according to claim 1, wherein the reaction pressure is 0.1 to 2MPa.
10. 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.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811456811.7A CN111253238B (en) | 2018-11-30 | 2018-11-30 | Method for preparing lactic acid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811456811.7A CN111253238B (en) | 2018-11-30 | 2018-11-30 | Method for preparing lactic acid |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111253238A CN111253238A (en) | 2020-06-09 |
| CN111253238B true CN111253238B (en) | 2023-03-10 |
Family
ID=70945038
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811456811.7A Active CN111253238B (en) | 2018-11-30 | 2018-11-30 | Method for preparing lactic acid |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111253238B (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104159883A (en) * | 2012-03-07 | 2014-11-19 | 麦兰特公司 | Preparation of alpha, beta-unsaturated carboxylic acids and esters thereof |
| CN106032283A (en) * | 2015-03-10 | 2016-10-19 | 中国石油化工股份有限公司 | Tin-titanium-silicon molecular sieve, preparation method and applications thereof, and cyclic ketone oxidation method |
-
2018
- 2018-11-30 CN CN201811456811.7A patent/CN111253238B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104159883A (en) * | 2012-03-07 | 2014-11-19 | 麦兰特公司 | Preparation of alpha, beta-unsaturated carboxylic acids and esters thereof |
| CN106032283A (en) * | 2015-03-10 | 2016-10-19 | 中国石油化工股份有限公司 | Tin-titanium-silicon molecular sieve, preparation method and applications thereof, and cyclic ketone oxidation method |
Non-Patent Citations (2)
| Title |
|---|
| Glycerol oxidehydration to pyruvaldehyde over silver-based catalysts for improved lactic acid production;Lari, G. M. et al;《GREEN CHEMISTRY》;20161231;第18卷(第17期);第4683和4691页 * |
| 催化法制备乳酸(酯)的研究进展;刘俊霞;《山东化工》;20170508(第09期);全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111253238A (en) | 2020-06-09 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN111253248B (en) | Method for preparing lactate by catalyzing methylglyoxal | |
| CN102309980B (en) | Steam modifying method of titanium-silicon molecular sieve | |
| CN102309983B (en) | Method for regenerating inactivated titanium silicon molecular sieve | |
| CN111253364B (en) | Method for preparing ketal and/or acetal glycerol by catalyzing glycerol | |
| CN111170982B (en) | Method for improving selectivity of cyclohexanone oxidation reaction product epsilon-caprolactone | |
| CN111253252B (en) | Method for preparing lactate by catalyzing sugar | |
| CN102309982A (en) | Steam regeneration method of deactivated titanium-silicon molecular sieve | |
| CN111253249B (en) | Method for preparing lactate | |
| CN111253363B (en) | Method for preparing ketal and/or aldol | |
| CN102452918B (en) | Method for preparing corresponding dicarboxylic acid by catalytic oxidation of hydroxy acid | |
| CN111253238B (en) | Method for preparing lactic acid | |
| CN111253250B (en) | Method for preparing lactate | |
| CN111253225B (en) | Method for preparing lactic acid | |
| CN111253245B (en) | Method for preparing lactic acid | |
| CN111253449B (en) | Method for preparing fructose | |
| CN102311128B (en) | Method for treating titanium-silicon molecular sieve | |
| CN107986293A (en) | A kind of Titanium Sieve Molecular Sieve and its synthetic method and application | |
| CN111253251B (en) | Method for preparing lactate | |
| CN111253259B (en) | Method for preparing lactate by catalyzing dihydroxyacetone and/or glyceraldehyde | |
| CN111253232B (en) | Method for preparing methylglyoxal | |
| CN111253226B (en) | Method for preparing lactic acid by catalyzing dihydroxyacetone and/or glyceraldehyde | |
| CN111250157B (en) | Method for preparing lactic acid by catalyzing sugar | |
| CN111253239B (en) | Method for preparing lactic acid by catalyzing methylglyoxal | |
| CN111253362A (en) | Method for preparing ketal and/or acetal glycerol | |
| CN111253237B (en) | Method for preparing methylglyoxal by catalyzing sugar |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |