Catalyst for preparing epoxypropane by propylene epoxidation method and method for preparing epoxypropane by propylene epoxidation

Abstract

The invention discloses a catalyst for preparing epoxypropane by a propylene epoxidation method. The catalyst comprises a nitrogen-containing ligand and a metal oxide-loaded TS-1 molecular sieve, based on 100% of the mass of the TS-1 molecular sieve, the content of metal in the metal oxide is 0.01%-2%; the ratio of silicon to titanium in the TS-1 molecular sieve is 30 to 200; metal in the metal oxide loaded on the TS-1 molecular sieve and the nitrogen-containing ligand are subjected to in-situ coordination in the process of preparing epoxypropane by a propylene epoxidation method to form the catalyst. By adopting the catalyst disclosed by the invention, the problems that potential safety hazards are generated due to overhigh hydrogen peroxide concentration in a traditional liquid-phase propylene epoxidation preparation method, and a titanium silicalite molecular sieve catalyst pore channel is easy to block so as to be inactivated are solved; and moreover, the conversion rate of hydrogen peroxide with the concentration of 5-40% and the yield and selectivity of epoxypropane are effectively improved.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical industry, and particularly relates to a catalyst for preparing propylene oxide through propylene epoxidation and a method for preparing propylene oxide through propylene epoxidation. Background Art

[0002] Propylene oxide (PO) is an important basic organic chemical raw material and the third largest organic chemical product among propylene derivatives, second only to polypropylene and acrylonitrile. At present, the industrial production methods of propylene oxide mainly include the chlorohydrin method and the co-oxidation method. The chlorohydrin method uses olefins and chlorine as raw materials, has a relatively short process, mature process, large operating load flexibility, good product selectivity, high yield, relatively safe production, low requirements for the purity of raw material propylene, and low investment; however, the production process has serious equipment corrosion, large Cl2 consumption, and a large amount of wastewater and waste residue produced during production. Although the co-oxidation method overcomes the shortcomings of the chlorohydrin method such as pollution, corrosion and the need for chlorine resources, it has a long process, large investment, large amount of by-products and restricted outlets. With the current increasing market demand, the two traditional main methods in industry, the chlorohydrin method and the co-oxidation method, are difficult to meet the current requirements of atomic economy and green chemistry. The preparation of propylene oxide (HPPO) by oxidizing propylene with hydrogen peroxide as the oxygen source has gradually replaced the chlorohydrin method due to its green process and simple process.

[0003] At present, the production process of HPPO uses TS-1 as a catalyst, and the concentration of hydrogen peroxide is 50%-70% (mostly 50%). High concentrations of hydrogen peroxide have great safety hazards in transportation, storage and use, and the pores of TS-1 are easily blocked, resulting in catalyst deactivation and decreased reactivity, which makes the cost and energy consumption of the HPPO method high. Although domestic and foreign researchers have also made a lot of efforts in the catalyst and its application of the HPPO method, progress is still slow.

[0004] For example, Chinese patent document CN101045716 uses phosphotungstic heteropolyacid salt as catalyst to realize catalytic epoxidation of propylene, uses high concentration H2O2 aqueous solution as oxidant, increases the concentration of propylene oxide in the reaction system, and in the presence of 40%-90% concentration of hydrogen peroxide, the conversion rate of hydrogen peroxide can reach more than 90%, which can reduce separation energy consumption; at the same time, it reduces the water content in the system, reduces the hydrolysis of heteropolyacid catalyst, and improves the stability of the catalyst. However, the catalyst cannot be recovered, resulting in high cost, and even lower concentrations of hydrogen peroxide cannot achieve efficient production of ethylene oxide.

[0005] Chinese patent document CN1103765C proposes to use active oxides such as hydrogen peroxide or organic peroxides to oxidize propylene to propylene oxide on heterogeneous catalysts such as titanium silicon molecular sieve or silicon dioxide-supported titanium dioxide. However, the catalyst has a low effective utilization rate of hydrogen peroxide and poor recyclability.

[0006] Chinese patent document CN113145116A discloses a monolithic TS-1 catalyst, which places a metal skeleton in a chemical vapor deposition furnace, and then feeds a raw material gas and other mixed gases into the chemical vapor deposition furnace, heating to grow a Si-doped carbon layer on the metal skeleton, and after the growth is completed, cooling to obtain a monolithic TS-1 catalyst carrier. However, the reaction temperature of the catalyst is relatively high, and more by-products such as propylene glycol ether will be generated.

[0007] Chinese patent document CN111718313A discloses a method for preparing propylene oxide using TS-1. The catalyst used in this method is TS-1, which has different oxygen contents in tail gas under different conditions. Complex operations are required to ensure that the oxygen content in the tail gas meets the requirements for safe operation.

[0008] Chinese patent document CN112978757A discloses a method for preparing a thin-flaked titanium silicon molecular sieve TS-1, which has an MFI topological structure, improves the exothermic diffusion path in the straight channel direction of the molecular sieve, improves the conversion rate of hydrogen peroxide and the selectivity of propylene oxide. However, the catalyst also has the characteristics of catalyst instability and poor recycling rate.

[0009] Chinese patent document CN109876857A discloses a method for catalyzing propylene epoxidation in a microchannel by using a metalloporphyrin-loaded titanium silicalite. The metalloporphyrin-loaded titanium silicalite produced by the method can greatly improve the yield of propylene oxide and is conducive to direct scale-up for industrial production. However, the yield of propylene oxide obtained by the catalyst and the method is still low, only about 80%, and the selectivity is also low.

[0010] Chinese patent document CN111085205A discloses a method for preparing a monolithic modified TS-1 catalyst based on carbon porous metal, which can improve the selectivity of propylene oxide, solve the problem of separation of catalyst and reaction liquid, greatly improve production efficiency and reduce production costs. However, the catalyst has low selectivity, which can lead to excessive ineffective decomposition of hydrogen peroxide and excessive oxygen concentration at the end of the reaction.

[0011] Chinese patent document CN102558100A discloses a method for catalyzing propylene epoxidation reaction by titanium silicon molecular sieve, wherein an inorganic salt alkaline buffer solution is added to the propylene epoxidation reaction zone, wherein the inorganic salt alkaline buffer solution refers to a mixed solution composed of a weak base salt and its conjugate acid. The inorganic salt alkaline buffer solution is composed of a weak base of ammonium salt, borate, phosphate or carbonate and its conjugate acid. By adding a small amount of inorganic alkaline buffer solution to the reaction solution, the ring-opening reaction of the product propylene oxide and the solvent can be effectively inhibited. The buffer can be an alkaline buffer solvent such as ammonium salt, borate and phosphate. The selectivity of propylene oxide can reach 97.49%, the yield of propylene oxide is 96.56%, and the conversion rate of hydrogen peroxide is 99.12%. However, the method uses buffer salts, which will produce a large amount of saline wastewater, which puts pressure on environmental protection.

[0012] Chinese patent document CN112791744A discloses a modified titanium silicon molecular sieve, comprising: titanium silicon molecular sieve, metal compounds, and non-metallic oxides. In the presence of the catalyst and the auxiliary agent, cyclohexene is mixed with hydrogen peroxide to carry out an oxidation reaction to obtain cyclohexene oxide. The auxiliary agent is selected from pyridine, imidazole, methylimidazole, etc. The modified titanium silicon molecular sieve has excellent stability, effectively improves the oxidation activity of cyclohexene, and has good selectivity and reaction stability for catalytic synthesis of cyclohexene oxide. This method modifies the molecular sieve by adding metals and non-metals to improve the reaction activity. On the one hand, the catalytic system of this method is only applicable to the cyclohexene epoxidation system, and is not effective in the propylene oxidation system to produce ethylene oxide. Summary of the invention

[0013] In view of the problems existing in the prior art and the directions for improvement, the present invention provides a catalyst for preparing propylene oxide by propylene epoxidation, so as to solve the safety hazards caused by excessively high hydrogen peroxide concentration in the traditional propylene epoxidation preparation method, and the problem that the pores of the titanium silicon molecular sieve catalyst are easily clogged and thus deactivated.

[0014] To achieve the above object, the present invention provides the following technical solutions:

[0015] A catalyst for preparing propylene oxide by propylene epoxidation, comprising a nitrogen-containing ligand and a TS-1 molecular sieve loaded with a metal oxide;

[0016] Taking the mass of the TS-1 molecular sieve as 100%, the metal content in the metal oxide is 0.01%-2%; the silicon-titanium ratio in the TS-1 molecular sieve is 30-200;

[0017] The metal in the metal oxide supported on the TS-1 molecular sieve is coordinated with the nitrogen-containing ligand in situ to form a catalyst during the process of preparing propylene oxide by propylene epoxidation.

[0018] Optionally, in the catalyst for preparing propylene oxide by propylene epoxidation provided by the present invention, the metal is selected from any one of copper, iron, manganese, nickel and cobalt.

[0019] Optionally, in the catalyst for preparing propylene oxide by propylene epoxidation provided by the present invention, the nitrogen-containing

[0020] Among them, R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 , R 18 , R 19 , R 20 Each is independently selected from hydrogen, C6-C10 unsubstituted or substituted aryl, C1-C5 straight or branched alkyl, C5-C6 cycloalkyl;

[0021] Preferably, R 1 , R 5 , R 6 are independently selected from hydrogen, methyl, ethyl or phenyl;

[0022] R 2 , R 3 , R 4 , R 15 , R 16 , R 17 , R 18 , R 19 , R 20 are independently selected from hydrogen, methyl, ethyl, phenyl, cyclohexane or cyclopentane;

[0023] R 7 , R 8 , R 9 , R 10 , R 11 , R 12 , R 13 , R 14 are independently selected from hydrogen, methyl or ethyl.

[0024] The present invention also provides a method for preparing propylene oxide by epoxidation of propylene, which uses the catalyst for preparing propylene oxide by epoxidation of propylene, and comprises the following steps:

[0025] In situ coordination of nitrogen-containing ligands and TS-1 molecular sieve loaded with metal oxides in a system of propylene, 5%-40% hydrogen peroxide and solvent forms a catalyst, and catalyzes propylene to undergo epoxidation reaction to obtain propylene oxide;

[0026] The molar ratio of the nitrogen-containing ligand to the hydrogen peroxide is (0.01-1):100.

[0027] Optionally, in the method for preparing propylene oxide by epoxidation of propylene provided by the present invention, the temperature of the epoxidation reaction is 25-80° C., and the time is 0.5-6 h.

[0028] Optionally, in the method for preparing propylene oxide by epoxidation of propylene provided by the present invention, the pressure of the epoxidation reaction is 0.1-1 MPa.

[0029] Optionally, in the method for preparing propylene oxide by epoxidation of propylene provided by the present invention, the solvent is selected from any one of anhydrous methanol, water, anhydrous ethanol, acetonitrile, isopropanol, anhydrous acetone, industrial methanol and industrial ethanol.

[0030] Optionally, in the method for preparing propylene oxide by epoxidation of propylene provided by the present invention, the epoxidation reaction is carried out in a reactor, comprising the following steps:

[0031] A nitrogen-containing ligand, a TS-1 molecular sieve loaded with metal oxides, a solvent and 5%-40% hydrogen peroxide are added to a reactor, and then the gas in the reactor is replaced with nitrogen and propylene gas respectively, and propylene is introduced to carry out epoxidation reaction. After the reaction is completed, separation is performed to obtain crude propylene oxide and a catalyst.

[0032] Optionally, in the method for preparing propylene oxide by epoxidation of propylene provided by the present invention, the epoxidation reaction is carried out in a fixed bed reactor, comprising the following steps:

[0033] The TS-1 molecular sieve loaded with metal oxide is filled into a fixed bed, and then a mixed solution of nitrogen-containing ligand, solvent and 5%-40% hydrogen peroxide is added into the fixed bed, and propylene gas is introduced to perform epoxidation reaction to obtain propylene oxide; preferably, the flow rate of the mixed solution of nitrogen-containing ligand, solvent and 5%-40% hydrogen peroxide added into the fixed bed is 1-3 ml·min -1 g -1 ;

[0034] During the epoxidation reaction, the molar ratio of the introduced propylene gas to the hydrogen peroxide is (1-2):1.

[0035] The preparation method of the metal oxide-loaded TS-1 molecular sieve mentioned in the present invention is not specifically limited, and the conventional method in the industry can be used, such as the following method:

[0036] 1) The metal precursor solution is fully mixed with titanium silicon molecular sieve TS-1 and then allowed to stand (e.g., ultrasonically treated for 0.5-2 hours and then allowed to stand for 8-15 hours;

[0037] 2) adding alkaline liquid to the solution of step 1), maintaining it at room temperature for 10-15 hours under stirring, filtering it, washing it with deionized water until it is neutral, and drying it at 80-120° C. for 10-15 hours; placing it in a muffle furnace and calcining it at 400-800° C. for 3-12 hours to obtain a TS-1 molecular sieve loaded with metal oxides.

[0038] Wherein, in step 1), the metal precursor is selected from a soluble metal salt, such as any one selected from copper acetate, copper nitrate, iron acetate, iron nitrate, manganese acetate, manganese nitrate, nickel acetate, nickel nitrate, cobalt nitrate and cobalt acetate;

[0039] The solvent used in the solution of the metal precursor is one or more of water, methanol, ethanol, acetone and isopropanol.

[0040] In step 2), the alkaline solution can be selected from one or more solutions including sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, ammonia water and hydrazine hydrate. The concentration and amount of the alkaline solution are not specifically limited, and the pH of the system can be adjusted to 8-14. The atmosphere during roasting can be selected from any one of air, nitrogen and argon.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] The present invention aims at the problems existing when the existing TS-1 catalyst is used for preparing ethylene oxide by propylene epoxidation, and improves the traditional titanium silicon molecular sieve catalyst. First, a cheap metal is loaded on the titanium silicon TS-1 molecular sieve, and then in situ in the propylene epoxidation reaction, the catalyst of nitrogen-metal / TS-1 molecular sieve is formed with the nitrogen-containing ligand. By adopting the catalyst of the present invention, not only the safety hazard caused by the excessively high concentration of hydrogen peroxide in the traditional liquid-phase propylene epoxidation preparation method and the problem that the pores of the titanium silicon molecular sieve catalyst are easily blocked and thus deactivated are solved, but also the conversion rate of hydrogen peroxide with a concentration of 5%-40%, the yield and selectivity of propylene oxide are effectively improved. The catalyst is not only suitable for a reaction kettle, but also for a fixed bed reactor, and the conversion rate of hydrogen peroxide reaches 98%, and the selectivity of propylene oxide reaches 99%. Moreover, when the catalyst provided by the present invention is used to prepare ethylene oxide from propylene, the solvent in the reaction can be recycled, there is no three wastes, the cost is low, and the efficiency is high. Compared with the present invention in which nitrogen-containing ligands are added during the reaction, if the nitrogen-containing ligands are doped with titanium silicon molecular sieves and calcined, and the resulting catalyst is added to the reaction system, the catalyst reaction efficiency is greatly reduced. DETAILED DESCRIPTION

[0043] The present invention is described in detail below by way of examples. It is necessary to point out that the following examples are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Those skilled in the art in this field can make some non-essential improvements and adjustments to the present invention based on the above content of the present invention.

[0044] If no specific experimental steps or conditions are specified in the examples and comparative examples, the conventional experimental steps or conditions described in the literature in the art can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be purchased commercially.

[0045] Example 1

[0046] After 0.15g of copper acetate was added to 500ml of ethanol solvent and dissolved completely, 500g of TS-1 (Si:Ti=200:1) was added, and then ultrasonicated for 1h, and then allowed to stand for 12h, and NaOH solution was added to adjust the system to pH=10, and then most of the solvent was removed by vacuum distillation after reflux at 80℃ for 12h, and then placed in a drying oven at 100℃ for 12h, and then the dried TS-1 was placed in a muffle furnace and calcined at 400℃ for 3h in air. Finally, 0.01% (mass content) Cu / TS-1 was obtained.

[0047] 8g of 0.01% Cu / TS-1, 90mg25% ammonia water, 640ml of anhydrous methanol, and 192ml of 10% hydrogen peroxide were added to the tetrafluoro liner of the metal reactor, the reactor was sealed, and the gas in the metal reactor was completely replaced with nitrogen and propylene gas, respectively, and the metal reactor was placed in a metal bath and heated to 25°C, and then the propylene gas was turned on and the gas constant pressure was maintained at 0.6MPa. After 6h of reaction, the metal reactor was placed in an ice water bath to cool down, and then the reactor was opened to centrifuge the catalyst and the reaction liquid. 2ml of liquid was taken out and the yield of propylene oxide was determined by GC, and 2ml of liquid was taken out and titrated with KMnO4 solution until the solution color turned red and did not change color for 30 seconds. The conversion rate of hydrogen peroxide, the yield of propylene oxide and the effective utilization rate of hydrogen peroxide in the reaction were calculated, and the specific results are shown in Table 1.

[0048] Example 2

[0049] After 8.3g of ferric acetate was added to 500ml of methanol solvent and dissolved completely, 500g of TS-1 (Si:Ti=200:1) was added, and then ultrasonicated for 1h, and then allowed to stand for 12h, KOH solution was added to adjust the system to pH=12, and then most of the solvent was removed by vacuum distillation after reflux at 80℃ for 12h, and then dried at 100℃ in a drying oven for 12h, and then the dried TS-1 was placed in a muffle furnace and calcined at 450℃ in air for 5h. Finally, 0.5% Fe / TS-1 was obtained.

[0050] 8g of 0.5% Fe / TS-1, 400mg 2-2'-bipyridine, 640ml of anhydrous ethanol, and 128ml of 15% hydrogen peroxide were added to the tetrafluoro liner of the metal reactor, the reactor was sealed, and the gas in the metal reactor was completely replaced with nitrogen and propylene gas, and then the metal reactor was placed in a metal bath and heated to 40°C, and then the propylene gas was turned on and the gas constant pressure was maintained at 0.7MPa. After reacting for 0.5h, the metal reactor was placed in an ice water bath to cool down, and then the reactor was opened to centrifuge the catalyst and the reaction liquid. 2ml of liquid was taken out and the yield of propylene oxide was determined by GC, and 2ml of liquid was taken out and titrated with KMnO4 solution until the solution color turned red and did not change color for 30 seconds. The conversion rate of hydrogen peroxide, the yield of propylene oxide and the effective utilization rate of hydrogen peroxide in the reaction were calculated, and the specific results are shown in Table 1.

[0051] Example 3

[0052] After 16.6g of ferric acetate was added to 800ml of methanol solvent and dissolved completely, 500g of TS-1 (Si:Ti=100:1) was added, and then ultrasonicated for 1h, and then allowed to stand for 12h, KOH solution was added to adjust the system to pH=12, and then most of the solvent was removed by vacuum distillation after reflux at 80℃ for 12h, and then dried at 100℃ in a drying oven for 12h, and then the dried TS-1 was placed in a muffle furnace and calcined at 450℃ in air for 5h. Finally, 1% Fe / TS-1 was obtained.

[0053] 8g of 1% Fe / TS-1, 400mg 2-2'-bipyridine, 640ml of anhydrous ethanol, and 128ml of 15% hydrogen peroxide were added to the tetrafluoro liner of the metal reactor, the reactor was sealed, and the gas in the metal reactor was completely replaced with nitrogen and propylene gas, and then the metal reactor was placed in a metal bath and heated to 40°C, and then the propylene gas was turned on and the gas constant pressure was maintained at 0.5MPa. After reacting for 0.5h, the metal reactor was placed in an ice water bath to cool down, and then the reactor was opened to centrifuge the catalyst and the reaction liquid. 2ml of liquid was taken out and the yield of propylene oxide was determined by GC, and 2ml of liquid was taken out and titrated with KMnO4 solution until the solution color turned red and did not change color for 30 seconds. The conversion rate of hydrogen peroxide, the yield of propylene oxide and the effective utilization rate of hydrogen peroxide in the reaction were calculated, and the specific results are shown in Table 1.

[0054] Example 4

[0055] After 2.5g of cobalt acetate was added to 500ml of ethanol solvent and dissolved completely, 500g of TS-1 (Si:Ti=200:1) was added, and then ultrasonicated for 1h, and then allowed to stand for 12h, and Na2CO3 solution was added to adjust the system to pH=10, and then most of the solvent was removed by vacuum distillation after reflux at 80℃ for 12h, and then dried at 100℃ in a drying oven for 12h, and then the dried TS-1 was placed in a muffle furnace and calcined at 600℃ under N2 gas for 7h. Finally, 0.1% Co / TS-1 was obtained.

[0056] 8g of 0.1% Co / TS-1, 200mg of pyridine, 640ml of anhydrous acetone, and 64ml of 30% hydrogen peroxide were added to the tetrafluoroethylene lining of the metal reactor, the reactor was sealed, and the gas in the metal reactor was completely replaced with nitrogen and propylene gas, and then the metal reactor was placed in a metal bath and heated to 50°C, and then the propylene gas was turned on and the gas constant pressure was maintained at 0.3MPa. After 2h, the metal reactor was placed in an ice water bath to cool down, and then the reactor was opened to centrifuge the catalyst and the reaction liquid. 2ml of liquid was taken out and the yield of propylene oxide was determined by GC, and 2ml of liquid was taken out and titrated with KMnO4 solution until the solution color turned red and did not change color for 30 seconds. The conversion rate of hydrogen peroxide, the yield of propylene oxide and the effective utilization rate of hydrogen peroxide in the reaction were calculated, and the specific results are shown in Table 1.

[0057] Example 5

[0058] After 37.5g of cobalt acetate was added to 500ml of ethanol solvent and dissolved completely, 500g of TS-1 (Si:Ti=200:1) was added, and then ultrasonicated for 1h, and then allowed to stand for 12h, and Na2CO3 solution was added to adjust the system to pH=10, and then most of the solvent was removed by vacuum distillation after reflux at 80℃ for 12h, and then dried at 100℃ in a drying oven for 12h, and then the dried TS-1 was placed in a muffle furnace and calcined at 600℃ under N2 gas for 7h. Finally, 1.5% Co / TS-1 was obtained.

[0059] 8g of 1.5% Co / TS-1, 200mg of pyridine, 640ml of anhydrous acetone, and 64ml of 30% hydrogen peroxide were added to the tetrafluoroethylene lining of the metal reactor, the reactor was sealed, and the gas in the metal reactor was completely replaced with nitrogen and propylene gas, respectively. The metal reactor was placed in a metal bath and heated to 50°C, and then the propylene gas was turned on to keep the gas constant pressure at 0.3MPa. After 2h, the metal reactor was placed in an ice water bath to cool down, and then the reactor was opened to centrifuge the catalyst and the reaction liquid. 2ml of liquid was taken out and the yield of propylene oxide was determined by GC, and 2ml of liquid was taken out and titrated with KMnO4 solution until the solution color turned red and did not change color for 30 seconds. The conversion rate of hydrogen peroxide, the yield of propylene oxide and the effective utilization rate of hydrogen peroxide in the reaction were calculated, and the specific results are shown in Table 1.

[0060] Example 6

[0061] After 5g of cobalt nitrate hexahydrate was dissolved in 500ml of deionized water, 500g of TS-1 (Si:Ti=200:1) was added, and then ultrasonicated for 1h, left to stand for 12h, and K2CO3 solution was added to adjust the system to pH=10. After reflux at 80℃ for 12h, most of the solvent was removed by vacuum distillation, and then placed in a drying oven at 100℃ for 12h, and then the dried TS-1 was placed in a muffle furnace and calcined at 450℃ in air for 9h. Finally, 0.2% Co / TS-1 was obtained.

[0062] 8g of 0.2% Co / TS-1, 998mg 2-2'-bipyridine, 640ml isopropanol, and 64ml 30% hydrogen peroxide were added to the tetrafluoro liner of the metal reactor, the reactor was sealed, and the gas in the metal reactor was completely replaced with nitrogen and propylene gas, and then the metal reactor was placed in a metal bath and heated to 70°C, and then the propylene gas was turned on and the gas constant pressure was maintained at 0.1MPa. After 2h, the metal reactor was placed in an ice water bath to cool down, and then the reactor was opened to centrifuge the catalyst and the reaction liquid. 2ml of liquid was taken out and the yield of propylene oxide was determined by GC, and 2ml of liquid was taken out and titrated with KMnO4 solution until the solution color turned red and did not change color for 30 seconds. The conversion rate of hydrogen peroxide, the yield of propylene oxide and the effective utilization rate of hydrogen peroxide in the reaction were calculated, and the specific results are shown in Table 1.

[0063] Example 7

[0064] After 5g of cobalt nitrate hexahydrate was dissolved in 500ml of deionized water, 500g of TS-1 (Si:Ti=50:1) was added, and then ultrasonicated for 1h, left to stand for 12h, and K2CO3 solution was added to adjust the system to pH=10. After reflux at 80℃ for 12h, most of the solvent was removed by vacuum distillation, and then placed in a drying oven at 100℃ for 12h, and then the dried TS-1 was placed in a muffle furnace and calcined at 450℃ in air for 9h. Finally, 0.2% Co / TS-1 was obtained.

[0065] 8g of 0.2% Co / TS-1, 998mg 2-2'-bipyridine, 640ml isopropanol, and 64ml 30% hydrogen peroxide were added to the tetrafluoro liner of the metal reactor, the reactor was sealed, and the gas in the metal reactor was completely replaced with nitrogen and propylene gas, and then the metal reactor was placed in a metal bath and heated to 80°C, and then the propylene gas was turned on and the gas constant pressure was maintained at 0.3MPa. After 2h, the metal reactor was placed in an ice water bath to cool down, and then the reactor was opened to centrifuge the catalyst and the reaction liquid. 2ml of liquid was taken out and the yield of propylene oxide was determined by GC, and 2ml of liquid was taken out and titrated with KMnO4 solution until the solution color turned red and did not change color for 30 seconds. The conversion rate of hydrogen peroxide, the yield of propylene oxide and the effective utilization rate of hydrogen peroxide in the reaction were calculated, and the specific results are shown in Table 1.

[0066] Example 8

[0067] After 5g of cobalt nitrate hexahydrate was dissolved in 500ml of deionized water, 500g of TS-1 (Si:Ti=200:1) was added, and then ultrasonicated for 1h, left to stand for 12h, and K2CO3 solution was added to adjust the system to pH=10. After reflux at 80℃ for 12h, most of the solvent was removed by vacuum distillation, and then placed in a drying oven at 100℃ for 12h, and then the dried TS-1 was placed in a muffle furnace and calcined at 450℃ in air for 9h. Finally, 0.2% Co / TS-1 was obtained.

[0068] 8g of 0.2% Co / TS-1, 998mg 2-2'-bipyridine, 640ml isopropanol, and 64ml 30% hydrogen peroxide were added to the tetrafluoro liner of the metal reactor, the reactor was sealed, and the gas in the metal reactor was completely replaced with nitrogen and propylene gas, and then the metal reactor was placed in a metal bath and heated to 80°C, and then the propylene gas was turned on and the gas constant pressure was maintained at 0.3MPa. After 2h, the metal reactor was placed in an ice water bath to cool down, and then the reactor was opened to centrifuge the catalyst and the reaction liquid. 2ml of liquid was taken out and the yield of propylene oxide was determined by GC, and 2ml of liquid was taken out and titrated with KMnO4 solution until the solution color turned red and did not change color for 30 seconds. The conversion rate of hydrogen peroxide, the yield of propylene oxide and the effective utilization rate of hydrogen peroxide in the reaction were calculated, and the specific results are shown in Table 1.

[0069] Example 9

[0070] After 45g of manganese nitrate tetrahydrate was added to 500ml of acetone solvent and dissolved completely, 500g of TS-1 (Si:Ti=200:1) was added, and then ultrasonicated for 1h, and then allowed to stand for 12h, and NH3·H2O solution was added to adjust the system to pH=14. After reflux at 80℃ for 12h, most of the solvent was removed by vacuum distillation, and then placed in a drying oven at 100℃ for 12h, and then the dried TS-1 was placed in a muffle furnace and calcined at 700℃ for 12h under argon. Finally, 2% Mn / TS-1 was obtained.

[0071] 8g of 2% Mn / TS-1, 100mg 1,10-phenanthroline, 640ml anhydrous methanol, and 64ml 5% hydrogen peroxide were added to the PTFE lining of the metal reactor, the reactor was sealed, and the gas in the metal reactor was completely replaced with nitrogen and propylene gas, respectively. The metal reactor was placed in a metal bath and heated to 70°C, and then the propylene gas was turned on and the gas constant pressure was maintained at 1MPa. After 4h, the metal reactor was placed in an ice water bath to cool down, and then the reactor was opened to centrifuge the catalyst and the reaction liquid. 2ml of liquid was taken out and the yield of propylene oxide was determined by GC, and 2ml of liquid was taken out and titrated with KMnO4 solution until the solution color turned red and did not change color for 30 seconds. The conversion rate of hydrogen peroxide, the yield of propylene oxide and the effective utilization rate of hydrogen peroxide in the reaction were calculated, and the specific results are shown in Table 1.

[0072] Example 10

[0073] After 1.1g of tetrahydrate manganese acetate was added to 500ml of ethanol solvent and dissolved completely, 500g of TS-1 (Si:Ti=30:1) was added, the solution was ultrasonicated for 1h, and then allowed to stand for 12h, and NH3·H2O solution was added to adjust the system to pH=10. After reflux at 80℃ for 12h, most of the solvent was removed by vacuum distillation, and then placed in a drying oven at 100℃ for 12h, and then the dried TS-1 was placed in a muffle furnace and calcined at 450℃ in air for 5h. Finally, 0.5% Mn / TS-1 was obtained.

[0074] 8g of 0.5% Mn / TS-1, 400mg of cyclopentylamine, 640ml of anhydrous acetonitrile, and 384ml of 5% hydrogen peroxide were added to the tetrafluoroethylene lining of the metal reactor, the reactor was sealed, and the gas in the metal reactor was completely replaced with nitrogen and propylene gas, respectively. The metal reactor was placed in a metal bath and heated to 40°C, and then the propylene gas was turned on to keep the gas constant pressure at 0.4MPa. After 6h, the metal reactor was placed in an ice water bath to cool down, and then the reactor was opened to centrifuge the catalyst and the reaction liquid. 2ml of liquid was taken out and the yield of propylene oxide was determined by GC, and 2ml of liquid was taken out and titrated with KMnO4 solution until the solution color turned red and did not change color for 30 seconds. The conversion rate of hydrogen peroxide, the yield of propylene oxide and the effective utilization rate of hydrogen peroxide in the reaction were calculated, and the specific results are shown in Table 1.

[0075] Embodiment 11

[0076] After 4.5g of nickel nitrate was dissolved in 500ml of isopropanol solvent, 500g of TS-1 (Si:Ti=200:1) was added, the solution was ultrasonicated for 1h, and then allowed to stand for 12h, and NH3·H2O solution was added to adjust the system to pH=10. After reflux at 80℃ for 12h, most of the solvent was removed by vacuum distillation, and then the solution was placed in a drying oven at 100℃ for 12h, and then the dried TS-1 was placed in a muffle furnace and calcined at 800℃ for 6h under N2 gas. Finally, 0.5% Ni / TS-1 was obtained.

[0077] 8g of 0.5% Ni / TS-1, 600mg of terpyridine, 640ml of industrial methanol, and 48ml of 40% hydrogen peroxide were added to the PTFE lining of the metal reactor, the reactor was sealed, and the gas in the metal reactor was completely replaced with nitrogen and propylene gas, respectively. The metal reactor was placed in a metal bath and heated to 60°C, and then the propylene gas was turned on to keep the gas constant pressure at 0.8MPa. After 1.5h, the metal reactor was placed in an ice water bath to cool down, and then the reactor was opened to centrifuge the catalyst and the reaction liquid. 2ml of liquid was taken out and the yield of propylene oxide was determined by GC, and 2ml of liquid was taken out and titrated with KMnO4 solution until the solution color turned red and did not change color for 30 seconds. The conversion rate of hydrogen peroxide, the yield of propylene oxide and the effective utilization rate of hydrogen peroxide in the reaction were calculated, and the specific results are shown in Table 1.

[0078] Example 12

[0079] After 33.2g of ferric acetate was added to 500ml of methanol solvent and dissolved completely, 500g of TS-1 (Si:Ti=200:1) was added, and then ultrasonicated for 1h, and then allowed to stand for 12h, KOH solution was added to adjust the system to pH=12, and then most of the solvent was removed by vacuum distillation after reflux at 80℃ for 12h, and then dried at 100℃ in a drying oven for 12h, and then the dried TS-1 was placed in a muffle furnace and calcined at 450℃ under argon for 5h. Finally, 2% Fe / TS-1 was obtained.

[0080] First, 2% Fe / TS-1 catalyst was tableted by a tabletting machine, and then the pressed catalyst was sieved, and then 5g of the catalyst was filled into a fixed bed. 800ml methanol, 240ml 5% hydrogen peroxide, and 70mg cyclohexylamine solution were prepared, and the liquid was pumped into the fixed bed by a plunger pump, with a flow rate of 5ml / min, and propylene gas was turned on, with a gas flow rate of 112ml / min. During the reaction, the pressure in the fixed bed was kept at 0.4MPa and the temperature was 40°C. The reaction was separated by a gas-liquid separator, 2ml of liquid was taken out and the yield of propylene oxide was determined by GC, 2ml of liquid was taken out, and titrated with KMnO4 solution until the solution color turned red and did not change color for 30 seconds. The conversion rate of hydrogen peroxide, the yield of propylene oxide, and the effective utilization rate of hydrogen peroxide in the reaction were calculated, and the specific results are shown in Table 1.

[0081] Embodiment 13

[0082] After 0.11g of tetrahydrate manganese acetate was completely dissolved in 500ml of anhydrous ethanol solvent, 500g of TS-1 (Si:Ti=200:1) was added, the solution was ultrasonicated for 1h, and then allowed to stand for 12h, and NH3·H2O solution was added to adjust the system to pH=10. After reflux at 80℃ for 12h, most of the solvent was removed by vacuum distillation, and then placed in a drying oven at 100℃ for 12h, and then the dried TS-1 was placed in a muffle furnace and calcined at 450℃ in air for 5h. Finally, 0.05% Mn / TS-1 was obtained.

[0083] First, 0.05% Mn / TS-1 catalyst was tabletted by a tabletting machine, and then the compressed catalyst was sieved, and 5g of the catalyst was filled into a fixed bed. 800ml of methanol, 40ml of 30% hydrogen peroxide, and 240mg of 2-2'-bipyridine solution were prepared, and the liquid was pumped into the fixed bed by a plunger pump, and the flow rate was 5ml / min. Propylene gas was turned on, and the gas flow rate was 120ml / min. The pressure in the fixed bed was kept to be 0.6MPa, and the temperature was 40 ℃ during the reaction. The reaction was separated by a gas-liquid separator, and 2ml of liquid was taken out and measured with GC to determine the productivity of propylene oxide, and 2ml of liquid was taken out and titrated with KMnO4 solution until the solution color turned red and did not change color for 30 seconds. The conversion rate of hydrogen peroxide, the productivity of propylene oxide, and the effective utilization rate of hydrogen peroxide in the reaction were calculated, and the specific results were shown in Table 1.

[0084] Embodiment 14

[0085] After 0.75g of copper acetate was added to 500ml of industrial ethanol solvent and dissolved completely, 500g of TS-1 (Si:Ti=200:1) was added, and then ultrasonicated for 1h, and then allowed to stand for 12h, and NaOH solution was added to adjust the system to pH=10, and then most of the solvent was removed by vacuum distillation after reflux at 80℃ for 12h, and then dried at 100℃ in a drying oven for 12h, and then the dried TS-1 was placed in a muffle furnace and calcined at 400℃ in air for 3h. Finally, 0.05% Cu / TS-1 was obtained.

[0086] First, 0.05%Cu / TS-1 catalyst was tabletted by a tabletting machine, and then the pressed catalyst was sieved, and 5g of the catalyst was filled into a fixed bed. 800ml of methanol, 30ml of 40% hydrogen peroxide, and 240mg of 2-2'-bipyridine solution were prepared, and the liquid was pumped into the fixed bed by a plunger pump, and the flow rate was 5ml / min. Propylene gas was turned on, and the gas flow rate was 130ml / min. The pressure in the fixed bed was kept at 0.6MPa and the temperature was 40°C during the reaction. The reaction was separated by a gas-liquid separator, and 2ml of liquid was taken out and the productivity of propylene oxide was measured by GC. 2ml of liquid was taken out and titrated with KMnO4 solution until the solution color turned red and did not change color for 30 seconds. The conversion rate of hydrogen peroxide, the productivity of propylene oxide, and the effective utilization rate of hydrogen peroxide in the reaction were calculated, and the specific results were shown in Table 1.

[0087] Embodiment 15

[0088] After 0.25g of cobalt nitrate hexahydrate was added to 500ml of deionized water and dissolved completely, 500g of TS-1 (Si:Ti=200:1) was added, and then ultrasonicated for 1h, left to stand for 12h, and K2CO3 solution was added to adjust the system to pH=10. After reflux at 80℃ for 12h, most of the solvent was removed by vacuum distillation, and then placed in a drying oven at 100℃ for 12h, and then the dried TS-1 was placed in a muffle furnace and calcined at 450℃ under oxygen for 9h. Finally, 0.01% Co / TS-1 was obtained.

[0089] First, 0.01% Co / TS-1 catalyst was tableted by a tabletting machine, and then the pressed catalyst was sieved and 5g of the catalyst was filled into a fixed bed. 800ml of methanol, 30ml of 40% hydrogen peroxide, and 140mg of 25% NH3·H2O solution were prepared, and the liquid was pumped into the fixed bed by a plunger pump at a flow rate of 5ml / min. The propylene gas was turned on and the gas flow rate was 140ml / min. During the reaction, the pressure in the fixed bed was kept at 0.6MPa and the temperature was kept at 40°C. The reaction was separated by a gas-liquid separator, 2ml of the liquid was taken out and the yield of propylene oxide was determined by GC, and 2ml of the liquid was taken out and titrated with KMnO4 solution until the solution color turned red and did not change color for 30 seconds. The conversion rate of hydrogen peroxide, the yield of propylene oxide, and the effective utilization rate of hydrogen peroxide in the reaction were calculated, and the specific results are shown in Table 1.

[0090] Example 16

[0091] After 22 mg of tetrahydrate manganese acetate was completely dissolved in 500 ml of ethanol solvent, 500 g of TS-1 (Si:Ti=200:1) was added, the solution was ultrasonicated for 1 hour, and then allowed to stand for 12 hours. NH3·H2O solution was added to adjust the system to pH=10. After reflux at 80°C for 12 hours, most of the solvent was removed by vacuum distillation, and then the mixture was placed in a drying oven at 100°C for 12 hours. The dried TS-1 was then placed in a muffle furnace and calcined at 450°C in air for 5 hours. Finally, 0.01% Mn / TS-1 was obtained.

[0092] First, 0.01% Mn / TS-1 catalyst was tableted by a tablet press, and then the pressed catalyst was sieved and 5g of the catalyst was filled into a fixed bed. 800ml methanol, 60ml 20% hydrogen peroxide, and 4mg 25% NH3·H2O solution were prepared, and the liquid was pumped into the fixed bed by a plunger pump at a flow rate of 5ml / min. The propylene gas was turned on and the gas flow rate was 112ml / min. During the reaction, the pressure in the fixed bed was kept at 0.6MPa and the temperature was kept at 40°C. The reaction was separated by a gas-liquid separator, 2ml of the liquid was taken out and the yield of propylene oxide was determined by GC, and 2ml of the liquid was taken out and titrated with KMnO4 solution until the solution color turned red and did not change color for 30 seconds. The conversion rate of hydrogen peroxide, the yield of propylene oxide, and the effective utilization rate of hydrogen peroxide in the reaction were calculated, and the specific results are shown in Table 1.

[0093] Embodiment 17

[0094] After 4.5 g of nickel nitrate was completely dissolved in 500 ml of isopropanol solvent, 500 g of TS-1 (Si:Ti=200:1) was added, and then ultrasonicated for 1 hour, and then allowed to stand for 12 hours, and NH3·H2O solution was added to adjust the solvent to pH=10. After reflux at 80°C for 12 hours, most of the solvent was removed by vacuum distillation, and then placed in a drying oven at 100°C for 12 hours, and then the dried TS-1 was placed in a muffle furnace and calcined at 800°C for 6 hours under N2 gas to finally obtain 0.5% Ni / TS-1.

[0095] 8g of 0.5% Ni / TS-1, 300mg of 2,3-dimethyl-2,3-butanediamine, 640ml of anhydrous methanol, and 48ml of 40% hydrogen peroxide were added to the tetrafluoro lining of the metal reactor, the reactor was sealed, and the gas in the metal reactor was completely replaced with nitrogen and propylene gas, respectively. The metal reactor was placed in a metal bath and heated to 60°C, and then the propylene gas was turned on and the gas pressure was kept at 0.8MPa. After 1.5h, the metal reactor was placed in an ice water bath to cool down, and then the reactor was opened to centrifuge the catalyst and the reaction liquid. 2ml of liquid was taken out and the yield of propylene oxide was determined by GC, and 2ml of liquid was taken out and titrated with KMnO4 solution until the solution color turned red and did not change color for 30 seconds. The conversion rate of hydrogen peroxide, the yield of propylene oxide and the effective utilization rate of hydrogen peroxide in the reaction were calculated, and the specific results are shown in Table 1.

[0096] Embodiment 18

[0097] After 4.5g of nickel nitrate was completely dissolved in 500ml of isopropanol solvent, 500g of TS-1 (Si:Ti=200:1) was added, and then ultrasonicated for 1h, and then allowed to stand for 12h, and NH3·H2O solution was added to adjust the system pH to 10. After reflux at 80℃ for 12h, most of the solvent was removed by vacuum distillation, and then placed in a drying oven at 100℃ for 12h, and then the dried TS-1 was placed in a muffle furnace and calcined at 800℃ for 6h under N2 gas. Finally, 0.5% Ni / TS-1 was obtained.

[0098] 8g of 0.5% Ni / TS-1, 300mg of terpyridine, 640ml of anhydrous methanol, and 48ml of 40% hydrogen peroxide were added to the tetrafluoro liner of the metal reactor, the reactor was sealed, and the gas in the metal reactor was completely replaced with nitrogen and propylene gas, respectively. The metal reactor was placed in a metal bath and heated to 60°C, and then the propylene gas was turned on to keep the gas constant pressure at 0.8MPa. After 1.5h, the metal reactor was placed in an ice water bath to cool down, and then the reactor was opened to centrifuge the catalyst and the reaction liquid. 2ml of liquid was taken out and the yield of propylene oxide was determined by GC, and 2ml of liquid was taken out and titrated with KMnO4 solution until the solution color turned red and did not change color for 30 seconds. The conversion rate of hydrogen peroxide, the yield of propylene oxide and the effective utilization rate of hydrogen peroxide in the reaction were calculated, and the specific results are shown in Table 1.

[0099] Embodiment 19

[0100] After 4.5 g of nickel nitrate was completely dissolved in 500 ml of isopropanol solvent, 500 g of TS-1 (Si:Ti=200:1) was added, and then ultrasonicated for 1 hour, and then allowed to stand for 12 hours, and NH3·H2O solution was added to adjust the system pH to 10. After reflux at 80°C for 12 hours, most of the solvent was removed by vacuum distillation, and then placed in a drying oven at 100°C for 12 hours, and then the dried TS-1 was placed in a muffle furnace and calcined at 800°C for 6 hours under N2 gas to finally obtain 0.5% Ni / TS-1.

[0101] 8g of 0.5% Ni / TS-1, 280mg 2-2'-bipyridine, 640ml anhydrous acetonitrile, and 48ml 40% hydrogen peroxide were added to the tetrafluoro lining of the metal reactor, the reactor was sealed, and the gas in the metal reactor was completely replaced with nitrogen and propylene gas, and then the metal reactor was placed in a metal bath and heated to 60°C, and then the propylene gas was turned on and the gas constant pressure was maintained at 0.8MPa. After 1.5h, the metal reactor was placed in an ice water bath to cool down, and then the reactor was opened to centrifuge the catalyst and the reaction liquid. 2ml of liquid was taken out and the yield of propylene oxide was determined by GC, and 2ml of liquid was taken out and titrated with KMnO4 solution until the solution color turned red and did not change color for 30 seconds. The conversion rate of hydrogen peroxide, the yield of propylene oxide and the effective utilization rate of hydrogen peroxide in the reaction were calculated, and the specific results are shown in Table 1.

[0102] Embodiment 20

[0103] After 4.5g of nickel nitrate was dissolved in 500ml of isopropanol solvent, 500g of TS-1 (Si:Ti=200:1) was added, and the solution was ultrasonicated for 1h, and then left to stand for 12h, and NH3·H2O solution was added to adjust the system pH to 10. After reflux at 80℃ for 12h, most of the solvent was removed by vacuum distillation, and then the solution was placed in a drying oven at 100℃ for 12h, and then the dried TS-1 was placed in a muffle furnace and calcined at 800℃ for 6h under N2 gas. Finally, 0.5% Ni / TS-1 was obtained.

[0104] 8g of 0.5% Ni / TS-1, 800mg of ligand L3, 640ml of industrial ethanol, and 48ml of 40% hydrogen peroxide were added to the tetrafluoroethylene lining of the metal reactor, the reactor was sealed, and the gas in the metal reactor was completely replaced with nitrogen and propylene gas, respectively. The metal reactor was placed in a metal bath and heated to 60°C, and then the propylene gas was turned on to keep the gas constant pressure at 0.8MPa. After 1.5h, the metal reactor was placed in an ice water bath to cool down, and then the reactor was opened to centrifuge the catalyst and the reaction liquid. 2ml of liquid was taken out and the yield of propylene oxide was determined by GC, and 2ml of liquid was taken out and titrated with KMnO4 solution until the solution color turned red and did not change color for 30 seconds. The conversion rate of hydrogen peroxide, the yield of propylene oxide and the effective utilization rate of hydrogen peroxide in the reaction were calculated, and the specific results are shown in Table 1.

[0105] Embodiment 21

[0106] After 0.25g of copper acetate was added to 500ml of industrial ethanol solvent and dissolved completely, 500g of TS-1 (Si:Ti=200:1) was added, and then ultrasonicated for 1h, and then allowed to stand for 12h, and NaOH solution was added to adjust the system to pH=10, and then refluxed at 80℃ for 12h and then most of the solvent was removed by vacuum distillation, and then placed in a drying oven at 100℃ for 12h, and then the dried TS-1 was placed in a muffle furnace and calcined at 400℃ for 3h in air. Finally, 0.01% Cu / TS-1 was obtained.

[0107] First, 0.01%Cu / TS-1 catalyst is tableted by a tabletting machine, and then the compressed catalyst is sieved, and 5g of the catalyst is filled in a fixed bed. Prepare 800ml of methanol, 240ml of 5% hydrogen peroxide, and 6mg of 25% hydrazine solution, and the liquid is pumped into the fixed bed by a plunger pump, and the flow rate is 5ml / min. The propylene gas is turned on, and the gas flow rate is 150ml / min. The pressure in the fixed bed is kept to be 0.6MPa, and the temperature is 40 ℃ during the reaction. The reaction is separated by a gas-liquid separator, and 2ml of liquid is taken out and measured with GC to determine the productive rate of propylene oxide, and 2ml of liquid is taken out and titrated with KMnO4 solution until the solution color turns red and does not change color for 30 seconds. Calculate the conversion rate of hydrogen peroxide, the propylene oxide productive rate, and the effective utilization rate of hydrogen peroxide in the reaction, and the specific results are shown in Table 1.

[0108] Embodiment 22

[0109] The method for preparing the catalyst is shown in Example 21.

[0110] First, 0.01%Cu / TS-1 catalyst is tableted by a tabletting machine, and then the compressed catalyst is sieved, and 5g of the catalyst is filled into a fixed bed. Prepare 800ml of methanol, 30ml of 40% hydrogen peroxide, and 0.04ml of 25% ammonia solution, and the liquid is pumped into the fixed bed by a plunger pump, and the flow rate is 10ml / min. The propylene gas is turned on, and the gas flow rate is 200ml / min. The pressure in the fixed bed is kept to be 0.6MPa, and the temperature is 60 ℃ during the reaction. The reaction is separated by a gas-liquid separator, and 2ml of liquid is taken out and measured with GC to determine the productivity of propylene oxide, and 2ml of liquid is taken out and titrated with KMnO4 solution until the solution color turns red and does not change color for 30 seconds. Calculate the conversion rate of hydrogen peroxide, the productivity of propylene oxide, and the effective utilization rate of hydrogen peroxide in the reaction, and the specific results are shown in Table 1.

[0111] Embodiment 23

[0112] The method for preparing the catalyst is shown in Example 16.

[0113] First, 0.01% Mn / TS-1 catalyst was tabletted by a tabletting machine, and then the pressed catalyst was sieved, and 5g of the catalyst was filled into a fixed bed. 800ml of methanol, 60ml of 20% hydrogen peroxide, and 240mg of 2-2' bipyridine solution were prepared, and the liquid was pumped into the fixed bed by a plunger pump, with a flow rate of 15ml / min, and propylene gas was turned on, with a gas flow rate of 168ml / min. During the reaction, the pressure in the fixed bed was kept at 0.7MPa and the temperature was 80°C. The reaction was separated by a gas-liquid separator, and 2ml of liquid was taken out to measure the yield of propylene oxide therein with GC, and 2ml of liquid was taken out and titrated with KMnO4 solution until the solution color turned red and did not change color for 30 seconds. The conversion rate of hydrogen peroxide, the yield of propylene oxide, and the effective utilization rate of hydrogen peroxide in the reaction were calculated, and the specific results are shown in Table 1.

[0114] Embodiment 24

[0115] The method for preparing the catalyst is shown in Example 16.

[0116] First, 0.01% Mn / TS-1 catalyst was tabletted by a tabletting machine, and then the pressed catalyst was sieved, and 1g of the catalyst was filled into a fixed bed. 800ml methanol, 60ml 20% hydrogen peroxide, and 350mg ligand L1 solution were prepared, and the liquid was pumped into the fixed bed by a plunger pump, with a flow rate of 1ml / min, and propylene gas was turned on, with a gas flow rate of 20ml / min. During the reaction, the pressure in the fixed bed was kept at 0.6MPa and the temperature was 50°C. The reaction was separated by a gas-liquid separator, and 2ml of the liquid was taken out and the yield of propylene oxide was measured by GC, and 2ml of the liquid was taken out and titrated with KMnO4 solution until the solution color turned red and did not change color for 30 seconds. The conversion rate of hydrogen peroxide, the yield of propylene oxide, and the effective utilization rate of hydrogen peroxide in the reaction were calculated, and the specific results are shown in Table 1.

[0117] Embodiment 25

[0118] The method for preparing the catalyst is shown in Example 16.

[0119] First, 0.01% Mn / TS-1 catalyst was tabletted by a tabletting machine, and then the pressed catalyst was sieved, and 1g of catalyst was filled into a fixed bed. 800ml methanol, 60ml 20% hydrogen peroxide, and 50mg ligand L2 solution were prepared, and the liquid was pumped into the fixed bed by a plunger pump, and the flow rate was 1ml / min. Propylene gas was turned on, and the gas flow rate was 20ml / min. The pressure in the fixed bed was kept at 0.4MPa and the temperature was 40°C during the reaction. The reaction was separated by a gas-liquid separator, and 2ml of liquid was taken out and the productivity of propylene oxide was measured by GC. 2ml of liquid was taken out and titrated with KMnO4 solution until the solution color turned red and did not change color for 30 seconds. The conversion rate of hydrogen peroxide, the productivity of propylene oxide, and the effective utilization rate of hydrogen peroxide in the reaction were calculated, and the specific results were shown in Table 1.

[0120] Embodiment 26

[0121] After 2.5g of cobalt acetate was added to 500ml of ethanol solvent and dissolved completely, 500g of TS-1 (Si:Ti=200:1) was added, and then ultrasonicated for 1h, and then allowed to stand for 12h, and Na2CO3 solution was added to adjust the system to pH=10, and then most of the solvent was removed by vacuum distillation after reflux at 80℃ for 12h, and then dried at 100℃ in a drying oven for 12h, and then the dried TS-1 was placed in a muffle furnace and calcined at 600℃ under N2 gas for 7h. Finally, 0.1% Co / TS-1 was obtained.

[0122] First, 0.1% Co / TS-1 catalyst is tableted by a tabletting machine, and then the compressed catalyst is sieved, and 5g catalyst is filled in a fixed bed. Prepare 800ml methanol, 40ml 30% hydrogen peroxide, and 200mg pyridine, and the liquid is pumped into the fixed bed by a plunger pump, and the flow rate is 5ml / min. The propylene gas is turned on, and the gas flow rate is 130ml / min. The pressure in the fixed bed is kept to be 0.4MPa, and the temperature is 40 ℃ during the reaction. The reaction is separated by a gas-liquid separator, and 2ml of liquid is taken out and measured with GC to determine the productive rate of propylene oxide, and 2ml of liquid is taken out and titrated with KMnO4 solution until the solution color turns red and does not change color for 30 seconds. Calculate the conversion rate of hydrogen peroxide, the propylene oxide productive rate, and the effective utilization rate of hydrogen peroxide in the reaction, and the specific results are shown in Table 1.

[0123] The corresponding ligand structures in the above examples are shown below:

[0124]

[0125] Among them, ligand L1 was prepared according to the following reference [1], ligand L2 was prepared according to the following reference [2], and ligand L3 was prepared according to the following reference [3].

[0126] [1] Zamalyutin, VV; et al. Russian Journal ofOrganic Chemistry(2018), 54(3),419-425.

[0127] [2]Vermaak, Vincent; et al. Advanced Synthesis&Catalysis (2020), 362(24), 5788-5793.

[0128] [3]Stolzenberg, Alan M.; Glazer, Paul A.; Foxman, Bruce M. InorganicChemistry(1986), 25(7),983-91.

[0129] Comparative Example 1

[0130] After 0.15g of copper acetate was added to 500ml of ethanol solvent and dissolved completely, 500g of TS-1 (Si:Ti=200:1) was added, and then placed in an ultrasonic bath for 1h, and then allowed to stand for 12h, and NaOH solution was added to adjust the system to pH=10, and then most of the solvent was removed by vacuum distillation after reflux at 80℃ for 12h, and then placed in a drying oven at 100℃ for 12h, and then the dried TS-1 was immersed in 500g of 25% ammonia water for 12h, placed in a drying oven at 100℃ for 12h, and then calcined at 400℃ in air for 3h. Finally, 0.01% Cu-N / TS-1 was obtained.

[0131] 8g of 0.01% Cu-N / TS-1, 640ml of anhydrous methanol, and 192ml of 10% hydrogen peroxide were added to the tetrafluoro liner of the metal reactor, the reactor was sealed, and the gas in the metal reactor was completely replaced with nitrogen and propylene gas, respectively, and the metal reactor was placed in a metal bath and heated to 25°C, and then the propylene gas was turned on and the gas constant pressure was maintained at 0.6MPa. After reacting for 6h, the metal reactor was placed in an ice water bath to cool down, and then the reactor was opened, and the catalyst and the reaction liquid were separated by centrifugation. 2ml of liquid was taken out and the yield of propylene oxide was determined by GC, and 2ml of liquid was taken out and titrated with KMnO4 solution until the solution color turned red and did not change color for 30 seconds. The conversion rate of hydrogen peroxide, the yield of propylene oxide and the effective utilization rate of hydrogen peroxide in the reaction were calculated, and the specific results are shown in Table 1.

[0132] Comparative Example 2

[0133] 8g of TS-1 (Si:Ti=200:1), 640ml of industrial methanol, and 192ml of 10% hydrogen peroxide were added to the PTFE liner of the metal reactor, the reactor was sealed, and the gas in the metal reactor was completely replaced with nitrogen and propylene gas, and then the metal reactor was placed in a metal bath and heated to 25°C, and then the propylene gas was turned on and the gas constant pressure was maintained at 0.6MPa. After reacting for 6h, the metal reactor was placed in an ice water bath to cool down, and then the reactor was opened, and the catalyst and the reaction liquid were separated by centrifugation. 2ml of liquid was taken out and the yield of propylene oxide was determined by GC, and 2ml of liquid was taken out and titrated with KMnO4 solution until the solution color turned red and did not change color for 30 seconds. The conversion rate of hydrogen peroxide, the yield of propylene oxide and the effective utilization rate of hydrogen peroxide in the reaction were calculated, and the specific results are shown in Table 1.

[0134] Comparative Example 3

[0135] After 45g of nickel nitrate was completely dissolved in 500ml of isopropanol solvent, 500g of TS-1 (Si:Ti=200:1) was added, and the solution was ultrasonicated for 1h, and then left to stand for 12h, and NH3·H2O solution was added to adjust the system pH to 10. After reflux at 80℃ for 12h, most of the solvent was removed by vacuum distillation, and then placed in a drying oven at 100℃ for 12h, and then the dried TS-1 was placed in a muffle furnace and calcined at 800℃ for 6h under N2 gas. Finally, 5% Ni / TS-1 was obtained.

[0136] 8g of 5% Ni / TS-1, 800mg of ligand L3, 640ml of industrial ethanol, and 48ml of 40% hydrogen peroxide were added to the PTFE lining of the metal reactor, the reactor was sealed, and the gas in the metal reactor was completely replaced with nitrogen and propylene gas, respectively. The metal reactor was placed in a metal bath and heated to 60°C, and then the propylene gas was turned on, and the gas constant pressure was maintained at 0.8MPa. After 1.5h, the metal reactor was placed in an ice water bath to cool down, and then the reactor was opened, and the catalyst and the reaction liquid were centrifuged. 2ml of liquid was taken out and the yield of propylene oxide was determined by GC, and 2ml of liquid was taken out and titrated with KMnO4 solution until the solution color turned red and did not change color for 30 seconds. The conversion rate of hydrogen peroxide, the yield of propylene oxide and the effective utilization rate of hydrogen peroxide in the reaction were calculated, and the specific results are shown in Table 1.

[0137] Comparative Example 4

[0138] After 22 mg of tetrahydrate manganese acetate was completely dissolved in 500 ml of ethanol solvent, 500 g of TS-1 (Si:Ti=200:1) was added, the solution was ultrasonicated for 1 hour, and then allowed to stand for 12 hours. NH3·H2O solution was added to adjust the system to pH=10. After reflux at 80°C for 12 hours, most of the solvent was removed by vacuum distillation, and then the mixture was placed in a drying oven at 100°C for 12 hours. The dried TS-1 was then placed in a muffle furnace and calcined at 450°C in air for 5 hours. Finally, 0.01% Mn / TS-1 was obtained.

[0139] First, 0.01% Mn / TS-1 catalyst was tableted by a tablet press, and then the pressed catalyst was sieved, and 5g of the catalyst was filled into a fixed bed. 800ml of methanol, 60ml of 20% hydrogen peroxide, and 4g of 25% NH3·H2O solution were prepared, and the liquid was pumped into the fixed bed by a plunger pump at a flow rate of 5ml / min. Propylene gas was turned on, and the gas flow rate was 220ml / min. During the reaction, the pressure in the fixed bed was kept at 0.6MPa and the temperature was 40°C. The reaction was separated by a gas-liquid separator, 2ml of liquid was taken out and the yield of propylene oxide was determined by GC, and 2ml of liquid was taken out and titrated with KMnO4 solution until the solution color turned red and did not change color for 30 seconds. The conversion rate of hydrogen peroxide, the yield of propylene oxide, and the effective utilization rate of hydrogen peroxide in the reaction were calculated, and the specific results are shown in Table 1.

[0140] Comparative Example 5

[0141] After 2.5g of cobalt acetate and 2.5g of ammonium molybdate were added to 500ml of ethanol solvent and dissolved completely, 500g of TS-1 (Si:Ti=50:1) was added, and then ultrasonicated for 1h, and then allowed to stand for 12h, and Na2CO3 solution was added to adjust the system to pH=10, and then refluxed at 80℃ for 12h, and then most of the solvent was removed by vacuum distillation, and then placed in a drying oven at 120℃ for 12h, and then the dried TS-1 was placed in a muffle furnace and calcined at 600℃ for 7h under N2 gas. Finally, 0.1%Co-0.5%Mo / TS-1 was obtained.

[0142] First, 0.1% Co-0.5% Mo TS-1 catalyst was tableted by a tabletting machine, and then the pressed catalyst was sieved, and 5g of the catalyst was filled into a fixed bed. 800ml of methanol, 60ml of 20% hydrogen peroxide, and 200mg of pyridine were prepared, and the liquid was pumped into the fixed bed by a plunger pump, with a flow rate of 5ml / min, and propylene gas was turned on, with a gas flow rate of 120ml / min. During the reaction, the pressure in the fixed bed was kept at 0.4MPa and the temperature was 40°C. The reaction was separated by a gas-liquid separator, and 2ml of liquid was taken out to measure the yield of propylene oxide therein with GC, and 2ml of liquid was taken out and titrated with KMnO4 solution until the solution color turned red and did not change color for 30 seconds. The conversion rate of hydrogen peroxide, the yield of propylene oxide, and the effective utilization rate of hydrogen peroxide in the reaction were calculated, and the specific results are shown in Table 1.

[0143] Calculation formula:

[0144] Hydrogen peroxide conversion rate = (n1-n2) / n1*100%

[0145] Propylene oxide yield = n3 / n1*100%

[0146] Effective utilization rate of hydrogen peroxide = n3 / (n1-n2)*100%

[0147] Wherein, n1 is the number of moles of hydrogen peroxide before the reaction, n2 is the number of moles of hydrogen peroxide after the reaction, and n3 is the number of moles of propylene oxide generated.

[0148] Table 1

[0149]

[0150]

[0151] From the data in the above table, it can be seen that the present invention greatly improves the selectivity of propylene oxide by modifying the TS-1 supported metal and adjusting the metal and the nitrogen-containing ligand added to the reaction system, which can be increased from 29% to 99% at the highest. In addition, the catalyst is applicable to a wide range of hydrogen peroxide concentrations, and hydrogen peroxide in the concentration range of 5%-40% can obtain good yields and selectivities. In addition, the catalyst can also be recycled, which can greatly save costs.

[0152] Specifically, by comparing Example 1 with Comparative Example 1, it can be seen that after adjusting the order of adding the nitrogen-containing ligands, although the conversion rate of hydrogen peroxide is high, the yield of propylene oxide is low and the effective utilization rate of hydrogen peroxide is low, indicating that it is unable to inhibit the generation of by-products.

[0153] By comparing Example 1 with Comparative Example 2, it can be seen that when the TS-1 catalyst is not loaded with metal and the nitrogen-containing ligand is not added, the conversion rate of hydrogen peroxide, the yield of propylene oxide and the effective utilization rate of hydrogen peroxide are significantly reduced, indicating that when TS-1 is used alone as a catalyst, the propylene epoxidation reaction effect is poor.

[0154] From the comparison between Example 20 and Comparative Example 3, it can be seen that increasing the metal loading excess can improve the conversion rate of hydrogen peroxide, but it will also lead to an increase in by-products.

[0155] By comparing Example 16 with Comparative Example 4, it can be seen that excessive use of the nitrogen-containing ligand will lead to a significant decrease in the conversion rate of hydrogen peroxide and the yield of propylene oxide, and an increase in by-products.

[0156] By comparing Example 26 with Comparative Example 5, it can be seen that when TS-1 is modified with metal and non-metal oxides and pyridine is used as a catalyst aid for propylene epoxidation, the hydrogen peroxide conversion rate, propylene oxide yield and effective utilization rate of hydrogen peroxide are significantly reduced.

[0157] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, technicians familiar with the field may make various corresponding changes and deformations based on the present invention, but these corresponding changes and deformations should all fall within the scope of protection of the claims of the present invention.

Claims

1. A catalyst for preparing propylene oxide by propylene epoxidation, characterized in that: A TS-1 molecular sieve comprising a nitrogen-containing ligand and a loaded metal oxide; Based on the mass of the TS-1 molecular sieve being 100%, the metal content in the metal oxide is 0.01%-2%, and the silicon-titanium ratio in the TS-1 molecular sieve is 30-200; The metal in the metal oxide supported on the TS-1 molecular sieve is coordinated with the nitrogen-containing ligand in situ to form a catalyst during the process of preparing propylene oxide by propylene epoxidation.

2. The catalyst for preparing propylene oxide by propylene epoxidation as claimed in claim 1, characterized in that: The metal is selected from any one of copper, iron, manganese, nickel and cobalt.

3. The catalyst for preparing propylene oxide by propylene epoxidation as claimed in claim 1, characterized in that: The nitrogen-containing ligand is selected from Any of; Among them, R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 , R 18 , R 19 , R 20 Each is independently selected from hydrogen, C6-C10 unsubstituted or substituted aryl, C1-C5 straight or branched alkyl, C5-C6 cycloalkyl; Preferably, R 1 , R 5 , R 6 are independently selected from hydrogen, methyl, ethyl or phenyl; R 2 , R 3 , R 4 , R 15 , R 16 , R 17 , R 18 , R 19 , R 20 are independently selected from hydrogen, methyl, ethyl, phenyl, cyclohexane or cyclopentane; R 7 , R 8 , R 9 , R 10 , R 11 , R 12 , R 13 , R 14 are independently selected from hydrogen, methyl or ethyl.

4. A method for preparing propylene oxide by epoxidation of propylene, characterized in that: The catalyst for preparing propylene oxide by propylene epoxidation according to any one of claims 1 to 3 comprises the following steps: In situ coordination of nitrogen-containing ligands and TS-1 molecular sieve loaded with metal oxides in a system of propylene, 5%-40% hydrogen peroxide and solvent forms a catalyst, and catalyzes propylene to undergo epoxidation reaction to obtain propylene oxide; The molar ratio of the nitrogen-containing ligand to the hydrogen peroxide is (0.01-1):

100.

5. The method for preparing propylene oxide by epoxidation of propylene as claimed in claim 4, characterized in that: The epoxidation reaction temperature is 25-80°C and the reaction time is 0.5-6h.

6. The method for preparing propylene oxide by epoxidation of propylene as claimed in claim 4, characterized in that: The pressure of the epoxidation reaction is 0.1-1 MPa.

7. The method for preparing propylene oxide by epoxidation of propylene as claimed in claim 4, characterized in that: The solvent is selected from any one of anhydrous methanol, water, anhydrous ethanol, acetonitrile, isopropanol, anhydrous acetone, industrial methanol and industrial ethanol.

8. The method for preparing propylene oxide by epoxidation of propylene as claimed in claim 4, characterized in that: The epoxidation reaction is carried out in a reactor and comprises the following steps: A nitrogen-containing ligand, a TS-1 molecular sieve loaded with metal oxides, a solvent and 5%-40% hydrogen peroxide are added to a reactor, and then the gas in the reactor is replaced with nitrogen, and propylene is introduced to carry out epoxidation reaction. After the reaction is completed, separation is performed to obtain crude propylene oxide and a catalyst.

9. The method for preparing propylene oxide by epoxidation of propylene as claimed in claim 4, characterized in that: The epoxidation reaction is carried out in a fixed bed reactor and comprises the following steps: The TS-1 molecular sieve loaded with metal oxide is filled into a fixed bed, and then a mixed solution of nitrogen-containing ligand, solvent and 5%-40% hydrogen peroxide is added into the fixed bed, and propylene gas is introduced to carry out epoxidation reaction to obtain propylene oxide.

10. The method for preparing propylene oxide by epoxidation of propylene as claimed in claim 9, characterized in that: The flow rate of the mixed solution of the nitrogen-containing ligand, the solvent and 5%-40% hydrogen peroxide added to the fixed bed and the ratio of the catalyst used are 1-3 ml·min -1 g -1 ; and / or During the epoxidation reaction, the molar ratio of the introduced propylene gas to the hydrogen peroxide is (1-2):1.

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