CN114345406A

CN114345406A - Method for preparing epoxy chloropropane by catalyzing epoxidation of 3-chloropropene, catalyst and preparation method

Info

Publication number: CN114345406A
Application number: CN202210049919.4A
Authority: CN
Inventors: 黄杰军; 徐林; 丁克鸿; 李幸霏; 顾高升; 韩兴有; 郑杨
Original assignee: Jiangsu Yangnong Chemical Group Co Ltd
Current assignee: Jiangsu Yangnong Chemical Group Co Ltd
Priority date: 2022-01-17
Filing date: 2022-01-17
Publication date: 2022-04-15

Abstract

The invention provides a method for preparing epichlorohydrin by catalyzing epoxidation of 3-chloropropene, a catalyst and a preparation method thereof, wherein the preparation method of the catalyst directly prepares a modified M-TS-1 molecular sieve catalyst by in-situ doping of a transition metal organic acid salt with a TS-1 molecular sieve, and has the characteristics of simplicity, convenience and high efficiency. The M-TS-1 molecular sieve catalyst weakens the regularity of crystal lattices, can enable an active center Ti to be more easily contacted with a substrate, and increases the reaction activity of 3-chloropropene epoxidation in a method for preparing epichlorohydrin by catalyzing 3-chloropropene epoxidation, and on the other hand, the introduction of transition metal heteroatoms reduces the generation of acid centers, thereby inhibiting the surface acidity of the catalyst, remarkably reducing the generation of byproducts, prolonging the service life of the catalyst and improving the stability of the catalyst.

Description

Method for preparing epoxy chloropropane by catalyzing epoxidation of 3-chloropropene, catalyst and preparation method

Technical Field

The invention relates to the technical field of catalyst preparation, in particular to the field of preparation of a titanium silicalite TS-1 catalyst, and particularly relates to a method for preparing epichlorohydrin by catalyzing epoxidation of 3-chloropropene, a catalyst and a preparation method.

Background

Epichlorohydrin is an important raw material for organic chemical industry and fine chemical industry. The epoxy resin synthesized by using the epoxy chloropropane as the raw material has the advantages of strong chemical medium corrosion resistance, strong cohesiveness, good chemical stability and the like, and has wide application in the fields of adhesives, coatings, casting materials, reinforcing materials and the like. At present, the production method of epichlorohydrin which has the most industrial prospect is to catalyze 3-chloropropene to perform epoxidation by using a titanium silicalite TS-1 catalyst. The titanium silicalite molecular sieve is a crystal material with a uniform pore structure and a high specific surface area, and is widely applied to the fields of fine chemical engineering and petrochemical engineering as an excellent heterogeneous catalyst. In 1983, the first report of the titanium silicalite TS-1 catalyst is one of the important milestones in the field of molecular sieve catalysis. Since then, the titanium silicalite TS-1 catalyst has been studied intensively by researchers and is applied to the industrial production field. Taking titanium silicalite TS-1 as catalyst and H₂O₂The catalyst is a reaction system of an oxidant, and can catalyze oxidation reactions such as olefin epoxidation, ketone ammoximation, aromatic hydrocarbon hydroxylation and the like with high selectivity under mild reaction conditions. At the same time, the oxidant is converted into H after the reaction₂O, no other chemical waste is generated. Therefore, the titanium silicalite TS-1 catalyst has the characteristic of environmental friendliness, accords with the concept of green chemistry, and draws the wide attention of researchers.

The traditional titanium silicalite TS-1 catalyst has many defects, such as low epoxidation selectivity, low catalytic activity, more byproducts, shorter service life of the catalyst and the like, so that the modification of the TS-1 catalyst to improve the service performance has great industrial application value.

CN110694676A discloses a preparation method for preparing a doped modified catalyst. The method mainly achieves the purpose of doping by adding the lanthanide metal compound in the preparation stage. The lanthanide metal is alkalescent, so that the acidity of the catalyst can be inhibited, and the adverse effect of an acidic site on a catalytic reaction is reduced. Since rare earth metals generally have the disadvantages of poor solubility, high cost and the like, the application of rare earth metals in the industrial field is limited.

CN109046446A discloses a modification method of a titanium silicalite molecular sieve. The method comprises the steps of impregnating a titanium silicalite molecular sieve for multiple times through a transition metal nitrate aqueous solution, then roasting, and repeating the impregnation and roasting processes for 2-3 times to obtain the doped titanium silicalite molecular sieve catalyst. The method can effectively improve the defects of the traditional TS-1 catalyst. However, the impregnation method has the disadvantages of complex process, repeated operation, high cost and the like, and is not favorable for industrial production.

LJiao et al disclose a method for constructing a framework-doped Fe-CN/TS-1 catalyst, and the results show that Fe and active center Ti have a synergistic effect, so that the catalytic activity is improved by 4-9 times (see "appl. Catal. B-environ.,2014,152: 383-389"), but the method has a long preparation process, a complex process and high cost, and limits the application of the method in the field of industrial production.

Therefore, it is required to develop a catalyst which is advantageous for industrial production and has high catalytic activity.

Disclosure of Invention

In view of the problems in the prior art, the invention provides a method for preparing epoxy chloropropane by catalyzing epoxidation of 3-chloropropene, a catalyst and a preparation method, and aims at the defects that the traditional TS-1 catalyst is easy to inactivate and has low activity, and the traditional TS-1 catalyst modification method has longer flow and complicated steps, the method for preparing the TS-1 molecular sieve catalyst by in-situ modification is constructed, and the prepared catalyst has high activity and stability in catalyzing epoxidation of 3-chloropropene to prepare epoxy chloropropane.

In order to achieve the purpose, the invention adopts the following technical scheme:

in a first aspect, the invention provides a preparation method of a transition metal organic acid salt modified M-TS-1 molecular sieve catalyst, which comprises the following steps:

(1) mixing a silicon source, alkyl ammonium hydroxide, a transition metal organic acid salt, a titanium source and a first solvent in water, carrying out hydrolysis reaction, adding a quaternary ammonium salt, and evaporating to obtain sol;

(2) and (2) crystallizing the sol obtained in the step (1) through a hydrothermal reaction, and separating to obtain the titanium silicalite molecular sieve.

According to the preparation method, the TS-1 catalyst is modified in situ by using the organic acid salt of the transition metal, firstly, the organic substance of the organic salt of the transition metal is decomposed and escaped in the subsequent roasting process, compared with the inorganic salt, an acid site is not left, and the selectivity of the catalyst to the epoxy chloropropane is obviously improved. And secondly, doping of the transition metal element on the TS-1 crystal lattice is directly realized by adopting an in-situ preparation mode, namely the transition metal element replaces titanium and/or silicon to occupy the TS-1 crystal lattice position, so that the electronic state of a titanium active site is changed, the catalytic activity is improved, and the titanium active center originally embedded in a unit cell is exposed due to the doping of the transition metal element, so that the catalytic activity is further improved.

According to the invention, a certain amount of transition metal organic acid salt is introduced into a silicon source, and the transition metal yard doped TS-1 molecular sieve catalyst can be obtained in situ without separation of an intermediate product. In particular, the acid radical of the organic acid salt used in the invention can be oxidized and decomposed under high-temperature calcination, and the situation that the conventional inorganic acid radical (such as sulfate radical, chloride ion and the like) remains in the molecular sieve to cause the increase of acid sites can not occur.

Preferably, the silicon source in step (1) comprises any one of or a combination of at least two of silica sol, tetramethyl orthosilicate, tetraethyl orthosilicate, tetrapropyl orthosilicate and tetrabutyl orthosilicate, wherein typical but non-limiting combinations are a combination of silica sol and tetramethyl orthosilicate, a combination of tetraethyl orthosilicate and tetramethyl orthosilicate, a combination of silica sol and tetraethyl orthosilicate, a combination of silica sol and tetrabutyl orthosilicate, a combination of tetrabutyl orthosilicate and tetrapropyl orthosilicate, preferably silica sol and/or tetraethyl orthosilicate. Preferred silicon sources have a better catalytic effect.

Preferably, the transition metal organic acid salt includes any one of formate, hydrated formate, acetate, hydrated acetate, propionate or hydrated propionate or a combination of at least two thereof, wherein typical but non-limiting combinations are a combination of formate and hydrated formate, a combination of formate and acetate, a combination of acetate and hydrated formate, a combination of hydrated acetate and hydrated formate, a combination of propionate and hydrated acetate, a combination of propionate and hydrated propionate, and a combination of formate and hydrated propionate.

Preferably, the transition metal element in the transition metal organic acid salt includes any one of zinc, cobalt, nickel or chromium or a combination of at least two thereof, wherein typical but non-limiting combinations are a combination of chromium and cobalt, a combination of zinc and nickel, a combination of nickel and cobalt, a combination of chromium and cobalt, and a combination of zinc and chromium.

Preferably, the transition metal organic acid salt is any one of zinc formate, cobalt formate, zinc acetate, cobalt acetate or cobalt propionate or a combination of at least two of them, wherein typical but non-limiting combinations are a combination of zinc formate and cobalt propionate, a combination of zinc formate and zinc acetate, a combination of zinc acetate and cobalt formate, and a combination of cobalt acetate and cobalt formate. The preferable organic acid salt of transition metal has better catalytic activity and selectivity.

Preferably, the titanium source comprises any one of or a combination of at least two of tetraethyl titanate, tetrabutyl titanate, isopropyl titanate, titanium tetrachloride or titanium sulfate, with typical but non-limiting combinations being combinations of tetraethyl titanate and tetrabutyl titanate, isopropyl titanate and tetrabutyl titanate, tetraethyl titanate and isopropyl titanate, titanium tetrachloride and titanium sulfate, preferably tetrabutyl titanate. The preferable tetrabutyl titanate can better provide a titanium source and has better catalytic effect.

Preferably, the quaternary ammonium salt comprises any one or a combination of at least two of tetrapropylammonium fluoride, tetrapropylammonium bromide, tetrapropylammonium chloride, tetrabutylammonium fluoride, tetrabutylammonium bromide or tetrabutylammonium chloride, wherein typical but non-limiting combinations are a combination of tetrapropylammonium fluoride and tetrapropylammonium bromide, a combination of tetrapropylammonium chloride and tetrapropylammonium bromide, a combination of tetrapropylammonium fluoride and tetrapropylammonium chloride, a combination of tetrabutylammonium bromide and tetrapropylammonium bromide, preferably any one or a combination of at least two of tetrapropylammonium bromide, tetrapropylammonium chloride, tetrabutylammonium bromide or tetrabutylammonium chloride. The preferred quaternary ammonium salt can prepare the catalyst with better catalytic performance

Preferably, the first solvent comprises an alcoholic solvent.

Preferably, the alcohol solvent comprises an isopropanol solution.

Preferably, hydrogen peroxide is also added in the mixing.

Preferably, the alkyl ammonium hydroxide comprises tetrapropyl ammonium hydroxide.

Preferably, the molar ratio of the silicon source to the alkylammonium hydroxide in step (1) is 1: 0.1-0.5, and may be, for example, 1:0.1, 1:0.15, 1:0.20, 1:0.24, 1:0.28, 1:0.30, 1:0.37, 1:0.40, 1:0.46 or 1:0.5, and preferably 1: 0.2-0.4.

Preferably, the molar ratio of the silicon source to the organic acid salt of the transition metal is 1:0.001 to 0.01, and may be, for example, 1:0.001, 1:0.002, 1:0.003, 1:0.004, 1:0.005, 1:0.006, 1:0.007, 1:0.008, 1:0.009, or 1:0.01, and preferably 0.004 to 0.006. The invention further preferably strictly controls the molar ratio of the silicon source to the organic acid salt of the transition metal, thereby finally controlling the content of the transition metal element in the catalyst, on one hand, avoiding the reduction of an active center position caused by the high content of the transition metal element and reducing the catalytic activity, on the other hand, effectively weakening the regularity of crystal lattices, promoting the contact of the active sites and a substrate, and promoting the exposure of the active centers embedded in unit cells.

Preferably, the molar ratio of the silicon source to the quaternary ammonium salt is 1:0.02 to 0.06, and may be, for example, 1:0.02, 1:0.03, 1:0.04, 1:0.05, 1:0.06, or the like, and is preferably 0.03 to 0.04.

The molar ratio of the silicon source to water is preferably 1:25 to 60, and may be, for example, 1:25, 1:29, 1:30, 1:38, 1:40, 1:45, 1:50, 1:53, 1:57, or 1:60, and preferably 1:40 to 50.

Preferably, the molar ratio of the silicon source to the titanium source is 1:0.01 to 0.05, for example, 1:0.01, 1:0.02, 1:0.03, 1:0.04, or 1:0.05, and preferably 1:0.02 to 0.04.

Preferably, the molar ratio of the silicon source to the first solvent is 1:0.1 to 0.5, and may be, for example, 1:0.1, 1:0.06, 1:0.12, 1:0.17, 1:0.20, 1:0.28, 1:0.30, 1:0.39, 1:0.45, or 1:0.5, and preferably 1:0.2 to 0.4.

Preferably, the evaporation removes the first solvent.

Preferably, the content of the first solvent in the evaporated system is 10 to 500ppm, for example, 10ppm, 65ppm, 100ppm, 170ppm, 200ppm, 280ppm, 330ppm, 390ppm, 450ppm or 500ppm, etc., preferably 20 to 200 ppm.

Preferably, water is supplemented in the evaporation.

The amount of the additional water is preferably 1 to 5 times the amount of the first solvent to be evaporated, and may be, for example, 1 time, 1.5 times, 2.0 times, 2.4 times, 2.8 times, 3.0 times, 3.7 times, 4.2 times, 4.6 times, or 5 times, and preferably 2 to 4 times.

Preferably, the mixing in step (1) comprises: the first mixed silicon source, alkyl ammonium hydroxide and transition metal organic acid salt are put into water for first hydrolysis, and then a first solvent containing a titanium source is dripped at a constant speed for second hydrolysis. The invention further prefers the mixing mode, wherein the titanium source is hydrolyzed slowly and then added, so that a uniform system can be better formed, and the prepared catalyst has higher stability.

Preferably, the temperature of the first hydrolysis is 55 to 95 ℃, for example, 55 ℃, 60 ℃, 64 ℃, 70 ℃, 73 ℃, 78 ℃, 82 ℃, 87 ℃, 91 ℃ or 95 ℃, preferably 60 to 80 ℃.

Preferably, the time of the first hydrolysis is 2 to 8 hours, for example, 2 hours, 2.5 hours, 3.0 hours, 4 hours, 4.7 hours, 5.4 hours, 6 hours, 6.7 hours, 7.4 hours or 8 hours, and the like, and preferably 4 to 6 hours.

Preferably, the first mixing is followed by stirring and then by warming to the first hydrolysis temperature.

Preferably, the stirring time is 2-8 h, for example, 2h, 2.5h, 3.0h, 4h, 4.7h, 5.4h, 6h, 6.7h, 7.4h or 8h, and preferably 4-6 h.

Preferably, the uniform dropping is completed within 0.5-2.5 h, for example, 0.5h, 0.8h, 1h, 1.2h, 1.4h, 1.7h, 1.9h, 2.1h, 2.3h or 2.5h, and the like, preferably 1-2 h.

Preferably, the system after the first hydrolysis is subjected to ice water bath and then is dropwise added at a constant speed.

Preferably, the temperature of the second hydrolysis is 50 to 90 ℃, for example, 50 ℃, 55 ℃, 60 ℃, 64 ℃, 68 ℃, 70 ℃, 77 ℃, 82 ℃, 86 ℃ or 90 ℃, preferably 60 to 70 ℃.

Preferably, the time of the second hydrolysis is 2 to 12 hours, for example, 2 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours or 12 hours, and preferably 4 to 8 hours.

Preferably, the temperature is raised to the second hydrolysis temperature after the uniform dropping.

Preferably, the first solvent containing the titanium source further contains hydrogen peroxide.

Preferably, the molar ratio of the silicon source to the hydrogen peroxide is 1:0.02 to 0.06, and may be, for example, 1:0.02, 1:0.025, 1:0.029, 1:0.034, 1:0.038, 1:0.043, 1:0.047, 1:0.052, 1:0.056, or 1:0.06, and preferably is 1:0.03 to 0.05.

Preferably, the crystallization temperature in step (2) is 120 to 240 ℃, for example, 120 ℃, 134 ℃, 147 ℃, 160 ℃, 174 ℃, 187 ℃, 200 ℃, 214 ℃, 227 ℃ or 240 ℃, preferably 140 to 180 ℃.

Preferably, the crystallization time is 12-96 h, for example, 12h, 22h, 31h, 40h, 50h, 59h, 68h, 78h, 87h or 96h, preferably 24-72 h.

Preferably, the separation comprises centrifugation.

Preferably, the rotation speed of the centrifugal separation is 2000-5000 r/min, such as 2000r/min, 2300r/min, 2600r/min, 3000r/min, 3300r/min, 3600r/min, 4000r/min, 4300r/min, 4600r/min or 5000r/min, preferably 3000-4000 r/min.

Preferably, the time for the centrifugal separation is 0.5 to 3 hours, for example, 0.5 hour, 0.8 hour, 1.1 hour, 1.4 hour, 1.7 hour, 1.9 hour, 2.2 hour, 2.5 hour, 2.8 hour or 3 hours, and the like, preferably 1 to 2 hours.

Preferably, the separation in step (2) further comprises drying.

Preferably, the drying temperature is 80-120 ℃, for example, 80 ℃, 85 ℃, 89 ℃, 94 ℃, 98 ℃, 103 ℃, 107 ℃, 112 ℃, 116 ℃ or 120 ℃, preferably 90-110 ℃.

Preferably, the drying time is 6-12 h, for example, 6h, 6.7h, 7.4h, 8h, 8.7h, 9.4h, 10h, 10.7h, 11.4h or 12h, etc., preferably 8-10 h.

Preferably, the preparation method further comprises, after the step (2):

(3) roasting the titanium-silicon molecular sieve in the step (2) for one time to obtain a first precursor;

(4) and (3) carrying out hydrothermal treatment on the first precursor in an ammonium salt solution, and then carrying out secondary roasting to obtain the M-TS-1 molecular sieve catalyst.

Preferably, the primary roasting in the step (3) is temperature programmed roasting.

Preferably, the temperature rise rate of the primary roasting is 2-10 ℃/min, for example, 2 ℃/min, 3 ℃/min, 4 ℃/min, 5 ℃/min, 6 ℃/min, 7 ℃/min, 8 ℃/min, 9 ℃/min or 10 ℃/min, etc., preferably 4-6 ℃/min.

Preferably, the final temperature of the primary baking is 500 to 700 ℃, for example, 500 ℃, 520 ℃, 540 ℃, 560 ℃, 580 ℃, 600 ℃, 634 ℃, 656 ℃, 670 ℃, 700 ℃, or the like, preferably 550 to 650 ℃.

Preferably, the heat preservation time of the primary roasting is 5-24 h, for example, 5h, 8h, 10h, 12h, 14h, 16h, 18h, 20h, 22h or 24h, and the like, and preferably 10-15 h.

Preferably, the first precursor is obtained by cooling after the first roasting.

Preferably, the mass ratio of the ammonium salt solution to the first precursor in the step (4) is 15-25: 1, for example, 15:1, 17:1, 18:1, 19:1, 20:1, 21:1, 22:1, 23:1, 24:1 or 25:1, and preferably 20: 1.

Preferably, the ammonium salt solution comprises any one of ammonium fluoride, ammonium bifluoride, ammonium bicarbonate, ammonium acetate, ammonium carbonate, ammonium chloride, aqueous ammonia, ammonium formate, ammonium phosphate or ammonium sulfate or a combination of at least two thereof.

Preferably, the concentration of the ammonium salt in the ammonium salt solution is 0.5-1.5 mol/L, for example, 0.5mol/L, 0.7mol/L, 0.8mol/L, 0.9mol/L, 1mol/L, 1.1mol/L, 1.2mol/L, 1.3mol/L, 1.4mol/L or 1.5mol/L, and the like, and preferably 1 mol/L.

Preferably, the temperature of the hydrothermal treatment is 40 to 100 ℃, for example, 40 ℃, 47 ℃, 54 ℃, 60 ℃, 65 ℃, 75 ℃, 80 ℃, 85 ℃, 90 ℃ or 100 ℃, preferably 50 to 90 ℃.

Preferably, the time of the hydrothermal treatment is 2 to 10 hours, for example, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours or 10 hours, and preferably 4 to 8 hours.

Preferably, the secondary roasting is temperature programmed roasting.

Preferably, the temperature rise rate of the secondary roasting is 2 to 10 ℃/min, for example, 2 ℃/min, 3 ℃/min, 4 ℃/min, 5 ℃/min, 6 ℃/min, 7 ℃/min, 8 ℃/min, 9 ℃/min or 10 ℃/min, etc., preferably 4 to 6 ℃/min.

Preferably, the final temperature of the secondary baking is 500 to 700 ℃, for example, 500 ℃, 520 ℃, 540 ℃, 560 ℃, 580 ℃, 600 ℃, 634 ℃, 656 ℃, 670 ℃, 700 ℃, or the like, preferably 550 to 650 ℃.

Preferably, the heat preservation time of the secondary roasting is 5-24 h, for example, 5h, 8h, 10h, 12h, 14h, 16h, 18h, 20h, 22h or 24h, and the like, and preferably 10-15 h.

Preferably, the M-TS-1 molecular sieve catalyst is obtained by cooling after secondary roasting

As a preferable technical solution of the first aspect of the present invention, the preparation method comprises:

(1) the first mixed silicon source, alkyl ammonium hydroxide and transition metal organic acid salt are put into water according to the molar ratio of 1: 0.1-0.5: 0.001-0.01, the molar ratio of the silicon source to the water is 1: 25-60, the mixture is stirred for 2-8 hours, then the temperature is raised to 55-95 ℃ for first hydrolysis for 2-8 hours, a first solvent containing a titanium source and hydrogen peroxide is dropwise added into the mixture at a constant speed within 0.5-2.5 hours, the molar ratio of the silicon source to the titanium source is 1: 0.01-0.05, the molar ratio of the silicon source to the first solvent is 1: 0.1-0.5, the molar ratio of the silicon source to the hydrogen peroxide is 1: 0.02-0.06, and then the mixture is heated to 50-90 ℃ for second hydrolysis for 2-12 hours; adding quaternary ammonium salt, wherein the molar ratio of the silicon source to the quaternary ammonium salt is 1: 0.02-0.06, evaporating to remove the first solvent until the content of the first solvent in the system is 10-500 ppm, and supplementing water with the evaporation amount of 1-5 times of that of the first solvent in evaporation to obtain sol;

(2) performing hydrothermal reaction on the sol obtained in the step (1), crystallizing at 120-240 ℃ for 12-96 h, performing centrifugal separation at 2000-5000 r/min for 0.5-3 h, and drying at 80-120 ℃ for 6-12 h to obtain a titanium-silicon molecular sieve;

(3) heating the titanium silicalite molecular sieve in the step (2) to 500-700 ℃ at a speed of 2-10 ℃/min, preserving heat for 5-24 h, roasting for the first time, and cooling to obtain a first precursor;

(4) and (3) carrying out hydrothermal treatment on the first precursor in 0.5-1.5 mol/L ammonium salt solution at 40-100 ℃ for 2-10 h, wherein the mass ratio of the ammonium salt solution to the first precursor is 15-25: 1, heating to 500-700 ℃ at the speed of 2-10 ℃/min, preserving heat for 5-24 h, carrying out secondary roasting, and cooling to obtain the M-TS-1 molecular sieve catalyst.

In a second aspect, the invention provides a transition metal organic acid salt modified M-TS-1 molecular sieve catalyst, wherein the M-TS-1 molecular sieve catalyst is prepared by the preparation method of the transition metal organic acid salt modified M-TS-1 molecular sieve catalyst in the first aspect.

Preferably, the content of the transition metal element M in the M-TS-1 molecular sieve catalyst is 0.05 to 0.8 wt%, and for example, may be 0.05 wt%, 0.06 wt%, 0.08 wt%, 0.1 wt%, 0.12 wt%, 0.2 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.8 wt%, or the like. The invention further preferably controls the content of M in the range, avoids the increase of M transition metal elements, reduces active sites, promotes the exposure of the originally embedded active sites, and controls the content of M to achieve the effects of inhibiting the formation of acid centers and prolonging the service life of the catalyst, thereby being more beneficial to the contact of the active sites and a substrate.

Preferably, the content of titanium element in the M-TS-1 molecular sieve catalyst is 2-3 wt%, for example, 2 wt%, 2.1 wt%, 2.2 wt%, 2.3 wt%, 2.4 wt%, 2.5 wt%, 2.6 wt%, 2.7 wt%, 2.8 wt%, 2.9 wt%, 3 wt%, etc.

In a third aspect, the invention provides a method for preparing epichlorohydrin by catalyzing epoxidation of 3-chloropropene, wherein the method adopts the transition metal organic acid salt modified M-TS-1 molecular sieve catalyst in the first aspect.

Preferably, the catalytic epoxidation of 3-chloropropene comprises: mixing methanol, 3-chloropropene, hydrogen peroxide and the M-TS-1 molecular sieve catalyst, and carrying out stirring reaction to prepare epichlorohydrin;

preferably, the mixing comprises: mixing methanol and 3-chloropropene, adding the M-TS-1 molecular sieve catalyst, and dropwise adding hydrogen peroxide while stirring.

Preferably, the hydrogen peroxide solution is continuously stirred for reaction after being dropwise added.

Preferably, the amount of the M-TS-1 molecular sieve catalyst is 2-7 g/mol of hydrogen peroxide, and may be, for example, 2g/mol, 2.5g/mol, 3g/mol, 3.5g/mol, 4g/mol, 4.5g/mol, 5g/mol, 5.5g/mol, 6g/mol, 6.5g/mol or 7 g/mol.

Preferably, the time for dropping the hydrogen peroxide is 60-180 min, for example, 60min, 70min, 80min, 100min, 120min, 140min, 150min or 180 min.

Preferably, the stirring reaction time is 1-3 h, for example, 1h, 1.2h, 1.5h, 2h, 2.5h or 3 h.

Preferably, the molar ratio of the methanol to the 3-chloropropene to the hydrogen peroxide is 2-3: 1, and may be, for example, 2:1:1, 2.5:1:1, 3:1:1, 2:1.5:1, 2.2:2:1, 2:2.5:1, 2:1:1, 2:3:1 or 2.5:2.2: 1.

Compared with the prior art, the invention has at least the following beneficial effects:

(1) the preparation method of the transition metal organic acid salt modified M-TS-1 molecular sieve catalyst provided by the invention adopts in-situ reaction, the preparation process is simple, the period is short, the used raw materials are cheap and easy to obtain, the reaction is easy to control, the production and modification costs of the TS-1 catalyst are reduced, and the industrial production is easy to realize;

(2) the transition metal organic acid salt modified M-TS-1 molecular sieve catalyst provided by the invention has the advantages that the transition metal is introduced into the crystal lattice of the TS-1 catalyst as a heteroatom, so that the regularity of the crystal lattice is weakened, and the contact of an active site and a substrate is facilitated, so that the prepared M-TS-1 catalyst catalyzes 3-chloropropene in H₂O₂Under the condition, the epoxidation reaction has higher reaction activity and selectivity, the conversion rate of hydrogen peroxide reaches more than 99 percent, the yield of epoxy chloropropane is still more than 95 percent, and the utilization rate of hydrogen peroxide is still more than 95 percent;

(3) the transition metal organic acid salt modified M-TS-1 molecular sieve catalyst provided by the invention has the advantages that the transition metal is alkalescent, so that the introduction of the transition metal can effectively inhibit the formation of an acid center of the TS-1 catalyst, thereby inhibiting the production of byproducts and prolonging the service life of the catalyst;

(4) in the method for preparing epichlorohydrin by catalyzing epoxidation of 3-chloropropene, the conversion rate of hydrogen peroxide after the catalyst is circulated for 11 times is still more than 99%, the yield of epichlorohydrin is still more than 95%, preferably more than 98%, and the utilization rate of hydrogen peroxide is still more than 95%, preferably more than 96%.

Drawings

FIG. 1 is a schematic diagram of the principle of catalyzing 3-chloropropene by using a transition metal organic acid salt modified M-TS-1 molecular sieve catalyst provided by the invention.

FIG. 2 is a molecular structure diagram of a transition metal organic acid salt modified M-TS-1 molecular sieve catalyst provided by the invention.

Fig. 3 is a partially enlarged view of the region I in fig. 2.

Detailed Description

The technical scheme of the invention is further explained by the specific implementation mode in combination with the attached drawings.

The present invention is described in further detail below. The following examples are merely illustrative of the present invention and do not represent or limit the scope of the claims, which are defined by the claims.

It is to be understood that in the description of the present invention, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

The invention provides a preparation method of a transition metal organic acid salt modified M-TS-1 molecular sieve catalyst, which comprises the following steps:

As another specific embodiment of the invention, the application of the M-TS-1 molecular sieve catalyst prepared by the above embodiment in catalyzing 3-chloropropene is provided, and the application method comprises the following steps:

mixing methanol and 3-chloropropene, adding the M-TS-1 molecular sieve catalyst, dropwise adding hydrogen peroxide while stirring, and continuously stirring for reaction after dropwise adding is finished to prepare the epichlorohydrin.

The catalytic principle is shown in fig. 1, the structure diagrams of the catalyst are shown in fig. 2-3, and it can be seen from fig. 2 and fig. 3 that a transition metal element replaces part of titanium in a TS-1 titanium silicalite molecular sieve, wherein M refers to the transition metal element, and the doping of the transition metal on lattice sites weakens the regularity of the lattice, so that an active center Ti can more easily contact a substrate, the reaction activity of 3-chloropropene epoxidation is increased, and the introduction of a transition metal heteroatom reduces the generation of an acid center, thereby inhibiting the surface acidity of the catalyst, significantly reducing the generation of by-products, prolonging the service life of the catalyst, and improving the stability of the catalyst.

Example 1

The embodiment provides a preparation method of a transition metal organic acid salt modified M-TS-1 molecular sieve catalyst, which comprises the following steps:

(1) according to the mol ratio of 0.2:0.02:0.0002, firstly mixing tetraethoxysilane, tetrapropylammonium hydroxide and cobalt acetate in 6mol of deionized water, uniformly stirring for 2h until the system is clear and transparent, then heating to 55 ℃ to carry out first hydrolysis for 2h, dropwise adding an isopropanol solution (0.02 mol of isopropanol) containing 0.002mol of tetrabutyl titanate and 0.004mol of hydrogen peroxide (with the concentration of 35 wt%) in an ice water bath at a constant speed within 0.5h, and heating to 50 ℃ after dropwise adding is finished to carry out second hydrolysis for 2 h; then adding 0.004mol of tetrapropyl ammonium bromide, evaporating to remove isopropanol until the content of the isopropanol in the system is less than 10ppm, and supplementing 0.81mol of water in the evaporation to obtain sol;

(2) performing hydrothermal reaction on the sol obtained in the step (1), crystallizing at 120 ℃ for 12 hours, performing centrifugal separation at 2000r/min for 0.5 hour, and performing forced air drying at 80 ℃ for 6 hours to obtain a titanium-silicon molecular sieve;

(3) heating the titanium silicalite molecular sieve in the step (2) to 500 ℃ at a speed of 2 ℃/min, preserving heat for 5 hours, roasting for the first time, and naturally cooling to obtain a first precursor;

(4) and (3) taking 40g of the first precursor in the step (3), carrying out hydrothermal treatment for 2h at 40 ℃ in 800g of 1mol/L ammonium bicarbonate solution, carrying out centrifugal separation at a centrifugal speed of 2000r/min for 0.5h, washing with deionized water, drying for 6h in an air-blast drying oven at 80 ℃, heating to 500 ℃ at a speed of 2 ℃/min, carrying out secondary roasting at a heat preservation time of 5h, and naturally cooling to room temperature to obtain the M-TS-1 molecular sieve catalyst. The catalyst had a cobalt content of 0.07 wt% and a titanium content of 2.44 wt% by ICP analysis.

Example 2

(1) firstly mixing tetraethoxysilane, tetrapropylammonium hydroxide and cobalt acetate in deionized water of 12mol according to a molar ratio of 0.2:0.1:0.002, uniformly stirring for 8h until the system is clear and transparent, then heating to 95 ℃ for first hydrolysis for 8h, dropwise adding an isopropanol solution (0.1 mol of isopropanol) containing 0.01mol of tetrabutyl titanate and 0.012mol of hydrogen peroxide (with the concentration of 35 wt%) in an ice water bath at a constant speed within 2.5h, and heating to 90 ℃ for second hydrolysis for 12h after dropwise adding; then 0.012mol of tetrapropylammonium bromide is added, the isopropanol is removed by evaporation until the content of the isopropanol in the system is less than 500ppm, and 4.2mol of water is added in the evaporation to obtain sol;

(2) performing hydrothermal reaction on the sol obtained in the step (1), crystallizing at 240 ℃ for 96 hours, performing centrifugal separation at 5000r/min for 3 hours, and performing forced air drying at 120 ℃ for 12 hours to obtain a titanium-silicon molecular sieve;

(3) heating the titanium silicalite molecular sieve in the step (2) to 700 ℃ at a speed of 10 ℃/min, preserving heat for 24 hours, roasting for the first time, and naturally cooling to obtain a first precursor;

(4) and (3) taking 40g of the first precursor in the step (3) to perform hydrothermal treatment for 10h at 100 ℃ in 800g of 1mol/L ammonium bicarbonate solution, performing centrifugal separation at the centrifugal speed of 5000r/min for 3h, washing with deionized water, drying for 12h in a 120 ℃ blast drying oven, heating to 700 ℃ at the speed of 10 ℃/min, performing secondary roasting at the temperature for 24h, and naturally cooling to room temperature to obtain the M-TS-1 molecular sieve catalyst. ICP analysis showed that the catalyst had a cobalt content of 0.76 wt% and a titanium content of 2.72 wt%.

Example 3

(1) adding a first mixed tetraethoxysilane, tetrapropylammonium hydroxide and cobalt acetate into 8mol of deionized water according to a molar ratio of 0.2:0.04:0.0008, uniformly stirring for 4h until the system is clear and transparent, heating to 60 ℃ to perform first hydrolysis for 4h, dropwise adding an isopropanol solution (0.04mol) containing 0.004mol of tetrabutyl titanate and 0.006mol of hydrogen peroxide (with the concentration of 35 wt%) in an ice water bath at a constant speed within 1h, and heating to 60 ℃ after dropwise adding to perform second hydrolysis for 4 h; then adding 0.006mol of tetrapropylammonium bromide, evaporating to remove isopropanol until the content of the isopropanol in the system is less than 20ppm, and supplementing 1.6mol of water in the evaporation to obtain sol;

(2) performing hydrothermal reaction on the sol obtained in the step (1), crystallizing at 140 ℃ for 24 hours, performing centrifugal separation at 3000r/min for 1 hour, and performing forced air drying at 90 ℃ for 8 hours to obtain a titanium-silicon molecular sieve;

(3) heating the titanium silicalite molecular sieve in the step (2) to 550 ℃ at a speed of 4 ℃/min, preserving heat for 10 hours, roasting for the first time, and naturally cooling to obtain a first precursor;

(4) and (3) taking 40g of the first precursor in the step (3), carrying out hydrothermal treatment for 4h at 50 ℃ in 800g of 1.2mol/L ammonium carbonate solution, carrying out centrifugal separation at the centrifugal speed of 3000r/min for 1h, washing with deionized water, drying for 8h in a 90 ℃ forced air drying oven, heating to 550 ℃ at the speed of 4 ℃/min, carrying out secondary roasting at the temperature of 10h, and naturally cooling to room temperature to obtain the M-TS-1 molecular sieve catalyst. The catalyst had a cobalt content of 0.31 wt% and a titanium content of 2.66 wt% as determined by ICP analysis.

Example 4

(1) according to the mol ratio of 0.2:0.08:0.0012, firstly mixing tetraethoxysilane, tetrapropylammonium hydroxide and cobalt acetate in 5mol of deionized water, uniformly stirring for 6h until the system is clear and transparent, then heating to 80 ℃ for carrying out first hydrolysis for 6h, dropwise adding an isopropanol solution (0.08mol) containing 0.008mol of tetrabutyl titanate and 0.01mol of hydrogen peroxide (with the concentration of 35 wt%) at a constant speed in an ice water bath within 2h, and heating to 50 ℃ for carrying out second hydrolysis for 2h after dropwise adding; then 0.008mol of tetrapropyl ammonium bromide is added, the isopropanol is removed by evaporation until the content of the isopropanol in the system is less than 200ppm, and 3.33mol of water is supplemented in the evaporation to obtain sol;

(2) performing hydrothermal reaction on the sol obtained in the step (1), crystallizing at 180 ℃ for 72h, performing centrifugal separation at 4000r/min for 2h, and performing forced air drying at 110 ℃ for 10h to obtain a titanium-silicon molecular sieve;

(3) heating the titanium silicalite molecular sieve in the step (2) to 650 ℃ at the speed of 6 ℃/min, preserving heat for 15h for primary roasting, and naturally cooling to obtain a first precursor;

(4) and (3) taking 40g of the first precursor in the step (3), carrying out hydrothermal treatment on the first precursor in 750g of 1.5mol/L ammonium formate solution at 90 ℃ for 8h, carrying out centrifugal separation at the centrifugal speed of 4000r/min for 2h, washing the first precursor with deionized water, drying the first precursor in a 110 ℃ forced air drying oven for 10h, heating the first precursor to 650 ℃ at the speed of 6 ℃/min, carrying out heat preservation for 15h for secondary roasting, and naturally cooling the second precursor to room temperature to obtain the M-TS-1 molecular sieve based catalyst. The catalyst had a cobalt content of 0.41 wt% and a titanium content of 2.43 wt% as determined by ICP analysis.

Example 5

(1) uniformly stirring a first mixed tetramethyl orthosilicate, tetrapropylammonium hydroxide and cobalt acetate in 7mol of deionized water according to a molar ratio of 0.2:0.03:0.0004 for 3h until a system is clear and transparent, heating to 58 ℃ for first hydrolysis for 3h, dropwise adding an isobutanol solution (0.03mol) containing 0.003mol of tetraethyl titanate and 0.005mol of hydrogen peroxide (with the concentration of 32 wt%) at a constant speed within 45min in an ice water bath, and heating to 55 ℃ for second hydrolysis for 3h after dropwise adding; then adding 0.005mol of tetrapropylammonium bromide, evaporating to remove isobutanol until the content of the isobutanol in the system is less than 15ppm, and supplementing 1.22mol of water in the evaporation to obtain sol;

(2) performing hydrothermal reaction on the sol obtained in the step (1), crystallizing at 130 ℃ for 20h, performing centrifugal separation at 2500r/min for 45min, and performing forced air drying at 85 ℃ for 7h to obtain a titanium-silicon molecular sieve;

(3) heating the titanium silicalite molecular sieve in the step (2) to 520 ℃ at a speed of 3 ℃/min, preserving heat for 7 hours, roasting for the first time, and naturally cooling to obtain a first precursor;

(4) and (3) taking 40g of the first precursor in the step (3) in 800g of 1mol/L ammonium bicarbonate solution, carrying out hydrothermal treatment at 45 ℃ for 3h, carrying out centrifugal separation at the centrifugal speed of 2500r/min for 45min, washing with deionized water, drying in an air-blast drying oven at 85 ℃ for 7h, heating to 520 ℃ at the speed of 3 ℃/min, carrying out secondary roasting at the temperature of 7h, and naturally cooling to room temperature to obtain the M-TS-1 molecular sieve catalyst. The catalyst had a cobalt content of 0.13 wt% and a titanium content of 2.67 wt% as determined by ICP analysis.

Example 6

(1) according to the mol ratio of 0.2:0.09:0.0016, firstly mixing tetraethoxysilane (0.2mol), tetrapropylammonium hydroxide and cobalt acetate in 11mol of deionized water, uniformly stirring for 7h until the system is clear and transparent, then heating to 75 ℃ for carrying out first hydrolysis for 7h, then dropwise adding an isopropanol solution (0.09mol) containing 0.009mol of tetrabutyl titanate and 0.011mol of hydrogen peroxide (35 wt%) at a constant speed in an ice water bath within 130min, and heating to 85 ℃ for carrying out second hydrolysis for 9h after dropwise adding; then adding 0.01mol of tetrapropyl ammonium bromide, evaporating to remove isopropanol until the content of the isopropanol in the system is less than 300ppm, and supplementing 3.76mol of water in the evaporation to obtain sol;

(2) performing hydrothermal reaction on the sol obtained in the step (1), crystallizing at 190 ℃ for 84h, performing centrifugal separation at 4500r/min for 150min, and performing forced air drying at 95 ℃ for 11h to obtain a titanium-silicon molecular sieve;

(3) heating the titanium silicalite molecular sieve in the step (2) to 670 ℃ at the speed of 8 ℃/min, preserving heat for 18h, roasting for the first time, and naturally cooling to obtain a first precursor;

(4) and (3) taking 40g of the first precursor in the step (3) in 800g of 1mol/L ammonium bicarbonate solution, carrying out hydrothermal treatment at 95 ℃ for 9h, carrying out centrifugal separation at the centrifugal speed of 4500r/min for 150min, washing with deionized water, drying in a 95 ℃ forced air drying oven for 11h, heating to 670 ℃ at the speed of 8 ℃/min, carrying out secondary roasting at the temperature of 18h, and naturally cooling to room temperature to obtain the M-TS-1 molecular sieve catalyst. The catalyst had a cobalt content of 0.56 wt% and a titanium content of 2.49 wt% as determined by ICP analysis.

Example 7

(1) according to the mol ratio of 0.2:0.06:0.001, adding first mixed ethyl orthosilicate (0.2mol), tetrapropylammonium hydroxide and cobalt acetate into 9mol of deionized water, uniformly stirring for 5h until the system is clear and transparent, then heating to 70 ℃ for first hydrolysis for 5h, dropwise adding an isopropanol solution (0.06mol) containing 0.006mol of tetrabutyl titanate and 0.008mol of hydrogen peroxide (35 wt% in concentration) at a constant speed within 150min under an ice water bath, and heating to 65 ℃ for second hydrolysis for 6h after dropwise adding; then 0.004mol of tetrapropylammonium bromide is added, isopropanol is removed by evaporation until the content of the isopropanol in the system is less than 150ppm, and 3.30mol of water is supplemented in the evaporation to obtain sol;

(2) carrying out hydrothermal reaction on the sol obtained in the step (1), crystallizing at 170 ℃ for 36h, carrying out centrifugal separation at 3500r/min for 90min, and carrying out forced air drying at 100 ℃ for 9h to obtain a titanium-silicon molecular sieve;

(3) heating the titanium silicalite molecular sieve in the step (2) to 600 ℃ at a speed of 5 ℃/min, preserving heat for 12 hours, roasting for the first time, and naturally cooling to obtain a first precursor;

(4) and (3) taking 40g of the first precursor in the step (3) in 800g of 1mol/L ammonium bicarbonate solution, carrying out hydrothermal treatment at 80 ℃ for 6h, carrying out centrifugal separation at a centrifugal speed of 3500r/min for 1.5h, washing with deionized water, drying in a 100 ℃ forced air drying oven for 9h, heating to 600 ℃ at a speed of 5 ℃/min, carrying out secondary roasting at a heat preservation time of 12h, and naturally cooling to room temperature to obtain the M-TS-1 molecular sieve catalyst. The catalyst had a cobalt content of 0.36 wt% and a titanium content of 2.61 wt% as determined by ICP analysis.

Examples 8 to 10

The other conditions were maintained as in example 7, and tetrapropylammonium bromide was replaced with other quaternary ammonium salts to give M-TS-1 catalysts, as detailed in Table 1, in which the cobalt content and titanium content were obtained by ICP analysis.

TABLE 1

Examples	Quaternary ammonium salt species	Cobalt content/wt%	Titanium content/wt%
				8	Tetrapropylammonium chloride	0.43	2.64
9	Tetrabutylammonium bromide	0.47	2.71
				10	Tetrabutyl ammonium chloride	0.46	2.70

Examples 11 to 19

The other conditions were maintained as in example 7, and the cobalt acetate was replaced with other transition metal organic acid salts to obtain M-TS-1 catalysts, as detailed in Table 2, in which the corresponding transition metal content and titanium content were obtained by ICP analysis.

TABLE 2

Examples 20 to 22

The cobalt acetate content was adjusted to give M-TS-1 catalysts, as detailed in Table 3, maintaining the other conditions as in example 7, wherein the corresponding transition metal content and titanium content were obtained by ICP analysis.

TABLE 3

Comparative example 1

This comparative example provides a preparation of a TS-1 catalyst, which is the same as example 7 except that cobalt acetate is not added in step (1). The titanium content of the catalyst was 2.82 wt% by ICP analysis.

Comparative example 2

This comparative example provides a process for the preparation of an impregnated M-TS-1 catalyst, which is the same as example 7 except that no cobalt acetate is added in step (1) and the same amount of cobalt acetate is added in step (4). The catalyst had a titanium content of 2.71 wt% and a cobalt content of 0.27 wt% as determined by ICP analysis.

Evaluation of catalyst: adding quantitative methanol and chloropropene into a stainless steel reaction kettle, uniformly mixing, adding an M-TS-1 catalyst, wherein the dosage of the M-TS-1 is 4g/mol of hydrogen peroxide, dropwise adding the hydrogen peroxide while stirring within 120min, and continuously stirring for reacting for 1.5h after the dropwise adding is finished. After the reaction is finished, the system is separated, the content of hydrogen peroxide in the reaction liquid is analyzed, the content of the whole index is quantitatively analyzed, and the like, so that the performance index of the catalyst is calculated. The results are shown in Table 4.

Catalyst evaluation conditions: n (methanol): n (chloropropene): n (hydrogen peroxide) ═ 2.2:2: 1; the reaction temperature was controlled at 35. + -. 5 ℃.

The full index content was quantitatively analyzed by gas chromatography. And detecting the residual hydrogen peroxide by an iodometry method. The specific method comprises the steps of taking 0.5g of reaction liquid, adding 1g of potassium iodide, uniformly mixing for 5 minutes in a dark place, adding 1g of ammonium molybdate, and then titrating with sodium thiosulfate. And (3) when the titration is carried out until the color of the solution changes, adding a starch indicator, and when the color of the solution is transparent, determining the titration end point.

The yield of the epichlorohydrin is equal to the mole number of the generated epichlorohydrin/the mole number of the converted hydrogen peroxide multiplied by 100 percent

The conversion rate of the hydrogen peroxide is equal to the mol number of the converted hydrogen peroxide/the mol number of the added hydrogen peroxide multiplied by 100 percent

The utilization rate of the hydrogen peroxide is equal to the mol number of the epoxidation product and the byproduct/the mol number of the converted hydrogen peroxide multiplied by 100 percent

TABLE 4

As can be seen from the catalyst evaluation results in Table 4, the M-TS-1 catalyst prepared by the method has higher hydrogen peroxide conversion rate, propylene oxide yield and hydrogen peroxide utilization rate for 3-chloropropene epoxidation reaction compared with the traditional TS-1 catalyst. The introduction of transition metal hetero atoms weakens the regularity of crystal lattices, so that active sites are easier to contact with substrates, and the catalytic activity of the TS-1 catalyst is further improved.

It can be seen from the combination of examples 7 and 20 to 22 that the content of the transition metal element in the product can be controlled by strictly controlling the addition amount of the transition metal organic acid salt in examples 7 and 20, so that the catalyst has better catalyst activity, that is, the utilization rate of hydrogen peroxide, the conversion rate and the yield of propylene oxide are all significantly improved.

And (3) repeatability evaluation: after completion of the primary catalytic reaction, the catalysts of example 7 and comparative example 1 were separated, and the epoxidation of 3-chloropropene was repeated under the same conditions to characterize the catalyst stability, and the results are detailed in table 5.

TABLE 5

The data of the stability of the epoxidation reaction of 3-chloropropene catalyzed by the M-TS-1 catalyst in Table 4 show that the M-TS-1 catalyst has good stability. When the circulation times reach 11 times, the performance of the catalyst is not obviously reduced, but the performance of the traditional TS-1 catalyst is greatly reduced. The transition metal is alkalescent, so that the acidity of the TS-1 molecular sieve is weakened, the generation of acid sites is reduced, the generation of byproducts is reduced, the stability of the catalyst is improved, and the service life of the catalyst is prolonged.

The applicant declares that the present invention illustrates the detailed structural features of the present invention through the above embodiments, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must be implemented depending on the above detailed structural features. It should be understood by those skilled in the art that any modifications of the present invention, equivalent substitutions of selected components of the present invention, additions of auxiliary components, selection of specific modes, etc., are within the scope and disclosure of the present invention.

Claims

1. A preparation method of a transition metal organic acid salt modified M-TS-1 molecular sieve catalyst is characterized by comprising the following steps:

2. The preparation method according to claim 1, wherein the transition metal organic acid salt in step (1) comprises any one of formate, hydrated formate, acetate, hydrated acetate, propionate or hydrated propionate or a combination of at least two thereof;

preferably, the transition metal element in the transition metal organic acid salt comprises any one or a combination of at least two of zinc, cobalt, nickel or chromium;

preferably, the transition metal organic acid salt is any one of zinc formate, cobalt formate, zinc acetate, cobalt acetate or cobalt propionate or a combination of at least two of the zinc formate, the cobalt formate, the zinc acetate, the cobalt acetate and the cobalt propionate;

preferably, the quaternary ammonium salt comprises any one or a combination of at least two of tetrapropylammonium fluoride, tetrapropylammonium bromide, tetrapropylammonium chloride, tetrabutylammonium fluoride, tetrabutylammonium bromide or tetrabutylammonium chloride, preferably any one or a combination of at least two of tetrapropylammonium bromide, tetrapropylammonium chloride, tetrabutylammonium bromide or tetrabutylammonium chloride;

preferably, the first solvent comprises an alcoholic solvent;

preferably, the alcohol solvent comprises an isopropanol solution;

preferably, hydrogen peroxide is also added in the mixing;

3. The preparation method according to claim 1 or 2, wherein the molar ratio of the silicon source to the alkyl ammonium hydroxide in step (1) is 1:0.1 to 0.5, preferably 1:0.2 to 0.4;

preferably, the molar ratio of the silicon source to the transition metal organic acid salt is 1: 0.001-0.01, preferably 0.004-0.006;

preferably, the molar ratio of the silicon source to the quaternary ammonium salt is 1: 0.02-0.06, preferably 0.03-0.04;

preferably, the molar ratio of the silicon source to the water is 1: 25-60, preferably 1: 40-50;

preferably, the molar ratio of the silicon source to the titanium source is 1: 0.01-0.05, preferably 1: 0.02-0.04;

preferably, the molar ratio of the silicon source to the first solvent is 1: 0.1-0.5, preferably 1: 0.2-0.4.

4. The method according to any one of claims 1 to 3, wherein the mixing in the step (1) comprises: a first mixed silicon source, alkyl ammonium hydroxide and transition metal organic acid salt are put into water for first hydrolysis, and then a first solvent containing a titanium source is dripped at a constant speed for second hydrolysis;

preferably, the temperature of the first hydrolysis is 55-95 ℃, and preferably 60-80 ℃;

preferably, the time of the first hydrolysis is 2-8 h, preferably 4-6 h;

preferably, the first mixing is followed by stirring and then heating to the first hydrolysis temperature;

preferably, the stirring time is 2-8 h, preferably 4-6 h;

preferably, the uniform dripping is completed within 0.5-2.5 h, preferably 1-2 h;

preferably, the temperature of the second hydrolysis is 50-90 ℃, and preferably 60-70 ℃;

preferably, the time of the second hydrolysis is 2-12 h, preferably 4-8 h;

preferably, after the uniform dropping, the temperature is raised to the second hydrolysis temperature;

preferably, the first solvent containing the titanium source also contains hydrogen peroxide;

preferably, the molar ratio of the silicon source to the hydrogen peroxide is 1: 0.02-0.06, preferably 1: 0.03-0.05.

5. The method according to any one of claims 1 to 4, wherein the temperature of the crystallization in the step (2) is 120 to 240 ℃, preferably 140 to 180 ℃;

preferably, the crystallization time is 12-96 h, preferably 24-72 h.

6. The method according to any one of claims 1 to 5, further comprising, after the step (2):

7. The production method according to any one of claims 1 to 6, wherein the primary roasting in the step (3) is temperature programmed roasting;

preferably, the temperature rise rate of the primary roasting is 2-10 ℃/min, and preferably 4-6 ℃/min;

preferably, the final temperature of the primary roasting is 500-700 ℃, and preferably 550-650 ℃;

preferably, the heat preservation time of the primary roasting is 5-24 hours, and preferably 10-15 hours;

preferably, the mass ratio of the ammonium salt solution in the step (4) to the first precursor is 15-25: 1, preferably 20: 1;

preferably, the ammonium salt solution comprises any one of ammonium fluoride, ammonium bifluoride, ammonium bicarbonate, ammonium acetate, ammonium carbonate, ammonium chloride, aqueous ammonia, ammonium formate, ammonium phosphate or ammonium sulfate or a combination of at least two of the above;

preferably, the concentration of the ammonium salt in the ammonium salt solution is 0.5-1.5 mol/L, preferably 1 mol/L;

preferably, the temperature of the hydrothermal treatment is 40-100 ℃, and preferably 50-90 ℃;

preferably, the time of the hydrothermal treatment is 2-10 h, preferably 4-8 h;

preferably, the secondary roasting is temperature programmed roasting;

preferably, the temperature rise rate of the secondary roasting is 2-10 ℃/min, and preferably 4-6 ℃/min;

preferably, the final temperature of the secondary roasting is 500-700 ℃, and preferably 550-650 ℃;

preferably, the heat preservation time of the secondary roasting is 5-24 hours, and preferably 10-15 hours.

8. The production method according to any one of claims 1 to 7, characterized by comprising:

9. A transition metal organic acid salt modified M-TS-1 molecular sieve catalyst, which is characterized in that the M-TS-1 molecular sieve catalyst is prepared by the preparation method of the transition metal organic acid salt modified M-TS-1 molecular sieve catalyst as claimed in any one of claims 1 to 8.

10. A method for preparing epichlorohydrin by catalyzing epoxidation of 3-chloropropene, which is characterized in that the method adopts the transition metal organic acid salt modified M-TS-1 molecular sieve catalyst of claim 9;

preferably, the method comprises: mixing methanol, 3-chloropropene, hydrogen peroxide and the M-TS-1 molecular sieve catalyst, and carrying out stirring reaction to prepare epichlorohydrin;

preferably, the mixing comprises: mixing methanol and 3-chloropropene, adding the M-TS-1 molecular sieve catalyst, and dropwise adding hydrogen peroxide while stirring;

preferably, the dosage of the M-TS-1 molecular sieve catalyst is 2-7 g/mol of hydrogen peroxide;

preferably, the time for dripping the hydrogen peroxide is 60-180 min;

preferably, the stirring reaction time is 1-3 h;

preferably, the mol ratio of the methanol to the 3-chloropropene to the hydrogen peroxide is 2-3: 1.