CN110143905B

CN110143905B - Process for preparing peroxypropionic acid

Info

Publication number: CN110143905B
Application number: CN201810150267.7A
Authority: CN
Inventors: 史春风; 林民; 朱斌
Original assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Current assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Priority date: 2018-02-13
Filing date: 2018-02-13
Publication date: 2021-05-14
Anticipated expiration: 2038-02-13
Also published as: CN110143905A

Abstract

The present disclosure relates to a process for preparing peroxypropionic acid, comprising: the propionic acid and the oxidant are subjected to contact reaction in the presence of a catalyst, wherein the catalyst is a titanium-silicon-aluminum molecular sieve catalyst. The method has the advantages of simple process, high propionic acid conversion rate, good propionic acid peroxide selectivity, easy production process control, and suitability for flexible production in various scales.

Description

Process for preparing peroxypropionic acid

Technical Field

The present disclosure relates to a process for preparing peroxypropionic acid.

Background

The peroxopropionic acid is colorless transparent liquid, has strong oxidation effect, is a commonly used high-efficiency disinfectant with strong sterilization capability, and can quickly kill various microorganisms including viruses, bacteria, fungi and spores. Furthermore, the peroxypropionic acid is also used as a bleaching agent for textiles, paper, grease, paraffin, starch, and also as an oxidizing agent and an epoxidizing agent in organic synthesis, such as synthesis of propylene oxide, glycerin, caprolactam, glycerin, epoxy plasticizer, and the like. In the prior art, there are two main methods for preparing peroxypropionic acid, the first is obtained by reacting propionic acid (or propionic anhydride) with hydrogen peroxide, and the second is obtained by directly oxidizing propionaldehyde. However, the existing method has complex preparation steps, harsh conditions and strict process control, and is not beneficial to industrial production.

Disclosure of Invention

The purpose of the disclosure is to provide a method for preparing peroxypropionic acid, which has simple process and higher conversion rate of raw materials and selectivity of products.

In order to achieve the above object, the present disclosure provides a method for preparing peroxypropionic acid, comprising: the propionic acid and the oxidant are subjected to contact reaction in the presence of a catalyst, wherein the catalyst is a titanium-silicon-aluminum molecular sieve catalyst.

Optionally, the titanium silicalite molecular sieve is at least one selected from a titanium silicalite molecular sieve with an MFI structure, a titanium silicalite molecular sieve with an MEL structure, a titanium silicalite molecular sieve with a BEA structure, a titanium silicalite molecular sieve with an MWW structure, a titanium silicalite molecular sieve with an MOR structure, a titanium silicalite molecular sieve with a TUN structure, and a titanium silicalite molecular sieve with a two-dimensional hexagonal structure.

Optionally, the step of preparing the titanium silicalite molecular sieve comprises:

(1) mixing and pulping a first discharging agent and an organic acid solution, carrying out first heat treatment on the obtained slurry, and separating to obtain a first solid, wherein the first discharging agent is a discharging agent of a reaction device which takes a titanium silicalite molecular sieve as a catalyst active component, and the conditions of the first heat treatment are as follows: the temperature is 20-45 ℃ and the time is 1-30 h;

(2) mixing the first solid, a silicon source, an aluminum source, a titanium source and an alkali source in the presence of an aqueous solvent, and then carrying out second heat treatment, wherein the conditions of the second heat treatment are as follows: the temperature is 100 ℃ and 200 ℃, and the time is 0.5-25 h;

or, the preparation steps of the titanium-silicon-aluminum molecular sieve comprise:

a. mixing and pulping a second discharging agent and an organic acid solution, carrying out third heat treatment on the obtained slurry, and separating to obtain a second solid with the relative crystallinity of 50-70%, wherein the second discharging agent is a discharging agent of a reaction device using a silicon-aluminum molecular sieve as a catalyst active component, and the conditions of the third heat treatment are as follows: the temperature is 50-150 ℃, and the time is 0.5-40 h;

b. mixing the second solid, a silicon source, a titanium source and an alkali source in the presence of an aqueous solvent, and then carrying out fourth heat treatment, wherein the conditions of the fourth heat treatment are as follows: the temperature is 100 ℃ and 200 ℃, and the time is 0.5-25 h.

Optionally, the weight ratio of the first discharging agent, the titanium source, the aluminum source, the organic acid, the alkali source and the water is 100: (0.1-10): (0.1-10): (0.005-50): (0.5-50): (20-1000), the first discharging agent is SiO₂The organic acid is counted as H⁺Counting as N when the alkali source contains nitrogen elements, and counting as OH < - > when the alkali source does not contain nitrogen elements; with SiO₂The silicon source is calculated by TiO₂Of metersThe molar ratio of the titanium source is (5-20): 1; the concentration of the organic acid solution is more than 0.1 mol/L.

Optionally, the discharging agent of the reaction device with the titanium silicalite molecular sieve as the catalyst active component in the step (1) is at least one selected from the group consisting of a discharging agent of an ammoximation reaction device, a discharging agent of a hydroxylation reaction device and a discharging agent of an epoxidation reaction device;

preferably, the titanium silicalite molecular sieve in step (1) is a titanium silicalite molecular sieve of MFI structure, and the activity of the first discharging agent is less than 50% of the activity of the titanium silicalite molecular sieve in fresh state;

preferably, in the step (2), the aluminum source and the alkali source are mixed in the presence of the aqueous solvent to obtain a mixed solution, and then the second heat treatment is performed after the mixed solution is mixed with the first solid and the titanium source.

Optionally, the weight ratio of the second discharging agent, the titanium source, the organic acid, the alkali source and the water is 100: (0.1-10): (0.005-50): (0.5-50): (20-1000), the second discharging agent is SiO₂The organic acid is counted as H⁺The alkali source is counted as N when containing nitrogen element, and the alkali source is counted as OH when not containing nitrogen element^-Counting; with SiO₂The silicon source is calculated by TiO₂The molar ratio of the titanium source is (5-20): 1; the concentration of the organic acid solution is more than 0.1 mol/L.

Optionally, the discharging agent of the reaction device with the silicon-aluminum molecular sieve as the catalyst active component in the step a is a discharging agent of a synthesis reaction device of hydrogen sulfide and methanol;

preferably, the silicoaluminophosphate molecular sieve in step a is a silicoaluminophosphate molecular sieve of MFI structure, and the activity of the second discharging agent is 50% or less of the activity of the silicoaluminophosphate molecular sieve when fresh.

Optionally, the organic acid is at least one selected from naphthenic acid, peracetic acid, and propionic acid; the alkali source is at least one selected from ammonia, aliphatic amine, aliphatic alcohol amine and quaternary ammonium base; the aluminum source is at least one selected from aluminum sol, aluminum salt, aluminum hydroxide and aluminum oxide; the titanium source is inorganic titanium salt and/or organic titanate; the silicon source is organosilicate.

Optionally, the molar ratio of propionic acid to oxidant is 1: (0.1-5), preferably 1: (0.2-2); the weight ratio of the propionic acid to the catalyst is (0.1-50): 1; the oxidant is at least one selected from hydrogen peroxide, tert-butyl hydroperoxide, cumyl peroxide and cyclohexyl hydroperoxide; the reaction conditions include: the temperature is 0-100 deg.C, and the pressure is 0.1-3 MPa.

Optionally, the reaction is carried out in the presence of a solvent, the weight ratio of the solvent to the propionic acid being (1-100): 1, the solvent is at least one selected from water, C1-C6 alcohol, C3-C8 ketone and C2-C6 nitrile.

Through the technical scheme, the method adopts the titanium-silicon-aluminum molecular sieve catalyst to catalyze the reaction of the propionic acid and the oxidant to produce the peroxypropionic acid, has simple process, high propionic acid conversion rate, good propionic acid product selectivity and easily controlled production process, and is suitable for various flexible production scales.

Additional features and advantages of the disclosure will be set forth in the detailed description which follows.

Detailed Description

The following describes in detail specific embodiments of the present disclosure. It should be understood that the detailed description and specific examples, while indicating the present disclosure, are given by way of illustration and explanation only, not limitation.

The present disclosure provides a process for preparing peroxypropionic acid, comprising: the propionic acid and the oxidant are subjected to contact reaction in the presence of a catalyst, wherein the catalyst is a titanium-silicon-aluminum molecular sieve catalyst. The method adopts the titanium-silicon-aluminum molecular sieve catalyst to catalyze the reaction of the propionic acid and the oxidant to produce the peroxypropionic acid, has simple process, high propionic acid conversion rate, good selectivity of the product peroxypropionic acid and easy control of the production process, and is suitable for various flexible production in scale.

According to the present disclosure, the titanium-silicon-aluminum molecular sieve refers to a generic term for a type of zeolite in which titanium atoms and aluminum atoms substitute for a part of silicon atoms in the lattice framework. The titanium silicalite molecular sieves can be common titanium silicalite molecular sieves with various topologies, such as: the titanium silicalite molecular sieve can be at least one of a titanium silicalite molecular sieve with an MFI structure (such as TS-1), a titanium silicalite molecular sieve with an MEL structure (such as TS-2), a titanium silicalite molecular sieve with a BEA structure (such as Ti-Beta), a titanium silicalite molecular sieve with an MWW structure (such as Ti-MCM-22), a titanium silicalite molecular sieve with an MOR structure (such as Ti-MOR), a titanium silicalite molecular sieve with a TUN structure (such as Ti-TUN), a titanium silicalite molecular sieve with a two-dimensional hexagonal structure (such as Ti-MCM-41 and Ti-SBA-15) and a titanium silicalite molecular sieve with other structures (such as Ti-ZSM-48). The titanium-silicon-aluminum molecular sieve is preferably at least one of a titanium-silicon-aluminum molecular sieve with an MFI structure, a titanium-silicon-aluminum molecular sieve with an MEL structure and a titanium-silicon-aluminum molecular sieve with a BEA structure, and more preferably is a titanium-silicon-aluminum molecular sieve with an MFI structure.

According to the present disclosure, the titanium-silicon-aluminum molecular sieve is used as a catalyst to achieve the purpose of the present disclosure, but the inventors of the present disclosure found in the research that the titanium-silicon-aluminum molecular sieve prepared by a specific method is particularly beneficial to improving the conversion rate of propionic acid and the selectivity of the product peroxypropionic acid.

Thus, according to a preferred embodiment of the present disclosure, the step of preparing the titanium silicalite molecular sieve comprises:

(1) mixing and pulping a first discharging agent and an organic acid solution, carrying out first heat treatment on the obtained slurry, and separating to obtain a first solid, wherein the first discharging agent is a discharging agent of a reaction device which takes a titanium silicalite molecular sieve as a catalyst active component, and the conditions of the first heat treatment are as follows: the temperature is 20-45 ℃, and the time is 1-30h, preferably 1-24h, more preferably 10-20 h;

(2) mixing the first solid, a silicon source, an aluminum source, a titanium source and an alkali source in the presence of an aqueous solvent, and then carrying out second heat treatment, wherein the conditions of the second heat treatment are as follows: the temperature is 100-200 ℃, preferably 120-180 ℃, more preferably 140-170 ℃ and the time is 0.5-25h, preferably 2-24h, more preferably 5-20 h.

In the above preferred embodiment, the relative crystallinity of the first solid obtained after the first heat treatment may be 70 to 90%. The first discharging agent can be processed into a first solid with specific relative crystallinity under specific first heat treatment conditions, and then the second heat treatment is carried out, so that the titanium-silicon-aluminum molecular sieve with excellent catalytic performance can be obtained, and the conversion rate of propionic acid and the selectivity of peroxypropionic acid can be further improved when the titanium-silicon-aluminum molecular sieve is used in the reaction of the disclosure. Wherein the relative crystallinity of the solid refers to the crystallinity of the solid relative to the fresh agent to which the discharge agent corresponds.

In the above preferred embodiment, the discharging agent of the reaction apparatus using the titanium silicalite as the catalyst active component may be discharging agent from various apparatuses using the titanium silicalite as the catalyst active component, for example, discharging agent from an oxidation reaction apparatus using the titanium silicalite as the catalyst active component. The oxidation reaction may be various oxidation reactions, for example, the discharging agent of the reaction apparatus using the titanium silicalite molecular sieve as the active component of the catalyst may be at least one of a discharging agent of an ammoximation reaction apparatus, a discharging agent of a hydroxylation reaction apparatus and a discharging agent of an epoxidation reaction apparatus, specifically at least one of a discharging agent of a cyclohexanone ammoximation reaction apparatus, a discharging agent of a phenol hydroxylation reaction apparatus and a discharging agent of a propylene epoxidation reaction apparatus, and preferably, the discharging agent is a catalyst that is deactivated by reaction in an alkaline environment, and therefore, for the purposes of the present invention, it is preferred that the first discharging agent is a discharging agent of a cyclohexanone ammoximation reaction apparatus (such as deactivated titanium silicalite TS-1, powdery molecular sieve having a particle size of 100-500 nm).

The discharging agent is a deactivated catalyst under the condition that the activity of the catalyst cannot be recovered to 50% of the initial activity by adopting a conventional regeneration method such as solvent washing or roasting, and the like (the initial activity refers to the average activity of the catalyst within 1h under the same reaction condition, for example, in the actual cyclohexanone oximation reaction, the initial activity of the catalyst is generally more than 95%). The activity of the discharging agent varies depending on its source. Generally, the activity of the discharging agent can be 5-95% of the activity of the titanium silicalite when fresh (i.e., the activity of the fresh agent). Preferably, the activity of the first discharging agent may be less than 50% of the activity of the titanium silicalite molecular sieve in a fresh state, and more preferably, the activity of the first discharging agent may be 10-40% of the activity of the titanium silicalite molecular sieve in a fresh state. The activity of the titanium silicalite molecular sieve in the fresh state is generally more than 90 percent, and usually more than 95 percent.

The discharge agent can be derived from an industrial deactivator or a deactivated catalyst after reaction in the laboratory. Certainly, from the perspective of preparation effect, the method disclosed by the disclosure can also adopt a fresh molecular sieve such as a titanium silicalite molecular sieve as a raw material, which is only unsuitable from the perspective of cost control and the like.

In the preferred embodiment described above, the discharging agent of each apparatus is measured by the reaction of each apparatus, and the discharging agent of the present invention is obtained as long as it is ensured that the activity of the discharging agent is lower than that of the fresh catalyst under the same reaction conditions in the same apparatus. As mentioned before, the activity of the discharging agent is preferably less than 50% of the activity of the fresh catalyst.

In the preferred embodiment, the discharging agent of the cyclohexanone ammoximation reaction apparatus is taken as an example, and the activity is measured by the following method:

taking a TS-1 molecular sieve (prepared by the method described in Zeolite, 1992, Vol.12: 943-950), TiO₂2.1%) was placed in a 100mL slurry bed reactor with continuous feed and membrane separation means, and a mixture of water and 30 wt% hydrogen peroxide (water to hydrogen peroxide volume ratio of 10: 9) a mixture of cyclohexanone and tert-butanol was added at a rate of 10.5mL/h (the volume ratio of cyclohexanone to tert-butanol was 1: 2.5) adding 36 wt% ammonia water at the speed of 5.7mL/h, simultaneously adding the three material flows, continuously discharging at the corresponding speed, maintaining the reaction temperature at 80 ℃, sampling the product every 1h after the reaction is stable, analyzing the composition of a liquid phase by using a gas chromatography, calculating the conversion rate of cyclohexanone by using the following formula, and taking the conversion rate as the activity of the titanium-silicon molecular sieve. Conversion of cyclohexanone [ (molar amount of cyclohexanone charged-molar amount of unreacted cyclohexanone)/molar amount of cyclohexanone charged]X 100%. Wherein the result of 1h is taken as the initial activity.

In the above preferred embodiment, the titanium silicalite molecular sieve can be common titanium silicalite molecular sieve with various topologies, such as: the titanium silicalite molecular sieve may be selected from one or more of a titanium silicalite molecular sieve of MFI structure (e.g., TS-1), a titanium silicalite molecular sieve of MEL structure (e.g., TS-2), a titanium silicalite molecular sieve of BEA structure (e.g., Ti-Beta), a titanium silicalite molecular sieve of MWW structure (e.g., Ti-MCM-22), a titanium silicalite molecular sieve of hexagonal structure (e.g., Ti-MCM-41, Ti-SBA-15), a titanium silicalite molecular sieve of MOR structure (e.g., Ti-MOR), a titanium silicalite molecular sieve of TUN structure (e.g., Ti-TUN), and a titanium silicalite molecular sieve of other structure (e.g., Ti-ZSM-48). Preferably, the titanium silicalite molecular sieve is selected from one or more of a titanium silicalite molecular sieve of an MFI structure, a titanium silicalite molecular sieve of an MEL structure and a titanium silicalite molecular sieve of a BEA structure. More preferably, the titanium silicalite molecular sieve is a titanium silicalite molecular sieve of MFI structure, such as TS-1 molecular sieve.

In the above preferred embodiment, the weight ratio of the first discharging agent, the titanium source, the aluminum source, the organic acid, the alkali source and the water may be 100: (0.1-10): (0.1-10): (0.005-50): (0.5-50): (20-1000), preferably 100: (0.5-10): (0.5-10): (1-15): (1-20): (100-800), more preferably the weight ratio of the first discharging agent to the organic acid is 100: (2-8), wherein the first discharging agent is SiO₂The organic acid is counted as H⁺The alkali source is counted as N when containing nitrogen element, and the alkali source is counted as OH when not containing nitrogen element^-And (6) counting. With SiO₂The silicon source is calculated by TiO₂The molar ratio of the titanium source may be (5-20): 1.

in the above preferred embodiment, the aluminum source is a substance capable of providing aluminum, and preferably the aluminum source is one or more of an aluminum sol, an aluminum salt, aluminum hydroxide and alumina, and the aluminum sol is preferably contained in an amount of 10 to 50 wt% based on the alumina. The aluminum salt may be an inorganic aluminum salt, which may be, for example, one or more of aluminum sulfate, sodium metaaluminate, aluminum chloride, and aluminum nitrate, and/or an organic aluminum salt, which is preferably a C1-C10 organic aluminum salt.

In the above preferred embodiment, the preferred step (2) may be performed as follows: mixing the aluminum source and the alkali source in the presence of a water-containing solvent to obtain a mixed solution, mixing the mixed solution with the first solid, the silicon source and the titanium source, and then carrying out the second heat treatment. Thus, the activity of the titanium-silicon-aluminum molecular sieve can be further improved.

The above preferred embodiment may further comprise a step of recovering the product from the second heat-treated material of step (2), wherein the step of recovering the product is a conventional method and familiar to those skilled in the art, and is not particularly required, and generally refers to a process of filtering, washing, drying and calcining the product. Wherein, the drying process can be carried out at the temperature of between 20 and 200 ℃, and the roasting process can be carried out at the temperature of between 300 and 800 ℃ in a nitrogen atmosphere for 0.5 to 6 hours and then in an air atmosphere for 3 to 12 hours.

Alternatively, according to another preferred embodiment of the present disclosure, the step of preparing the titanium silicalite molecular sieve may comprise:

a. mixing and pulping a second discharging agent and an organic acid solution, carrying out third heat treatment on the obtained slurry, and separating to obtain a second solid, wherein the second discharging agent is a discharging agent of a reaction device which takes a silicon-aluminum molecular sieve as an active component of a catalyst, and the conditions of the third heat treatment are as follows: the temperature is 50-150 ℃, and the time is 0.5-40h, preferably 1-24h, more preferably 10-20 h;

b. mixing the second solid, a silicon source, a titanium source and an alkali source in the presence of an aqueous solvent, and then carrying out fourth heat treatment, wherein the conditions of the fourth heat treatment are as follows: the temperature is 100-200 ℃, preferably 120-180 ℃, more preferably 140-170 ℃ and the time is 0.5-25h, preferably 2-24h, more preferably 5-20 h.

In the above preferred embodiment, the relative crystallinity of the second solid obtained after the third heat treatment may be 50 to 70%. The second discharging agent can be processed into a second solid with specific relative crystallinity under specific third heat treatment conditions, and then the fourth heat treatment is carried out, so that the titanium-silicon-aluminum molecular sieve with excellent catalytic performance can be obtained, and the conversion rate of propionic acid and the selectivity of peroxypropionic acid can be further improved when the titanium-silicon-aluminum molecular sieve is used in the reaction of the present disclosure. The relative crystallinity is determined as described above.

In the preferred embodiment described above, the particular definitions of the discharging agent are as described above, except that the titanium silicalite is replaced with a silicoaluminophosphate. The discharging agent of the reaction device using the aluminosilicate molecular sieve as the catalyst active component may be a discharging agent discharged from various devices using the aluminosilicate molecular sieve as the catalyst active component, for example, a discharging agent discharged from a synthesis reaction device using the aluminosilicate molecular sieve as the catalyst active component (such as a discharging agent of a synthesis reaction device of hydrogen sulfide and methanol), or a discharging agent discharged from a catalytic cracking reaction device using the aluminosilicate molecular sieve as the catalyst active component. Preferably, the discharging agent is a catalyst deactivated in reaction under an alkaline environment, and therefore, for the purposes of the present disclosure, the second discharging agent is preferably a discharging agent (such as deactivated silicon-aluminum molecular sieve ZSM-5, powdery, and the particle size is 100-500nm) of a synthesis reaction device of hydrogen sulfide and methanol.

As mentioned above, the activity of the second discharging agent is preferably 50% or less of the activity of the aluminosilicate molecular sieve in the fresh state.

In the preferred embodiment, the activity is measured by taking as an example the discharging agent of the apparatus for the synthesis reaction of hydrogen sulfide and methanol:

ZSM-5 molecular sieve (prepared by the method described in example 1 of CN 1715185A) is treated with water vapor at 200 deg.C for 10h, then tableted, sieved, and 20-40 mesh particles are loaded into a tubular reaction tube with diameter of 0.8cm and length of 55cm, and the bed volume of catalyst particles is 2.0cm³. The reaction temperature is 300 ℃, the reaction pressure is 1atm, the feeding molar ratio of hydrogen sulfide and methanol is 1:2, and the total gas volume space velocity is 700h^-1Under the conditions of (1), a catalytic reaction for synthesizing dimethyl sulfide is carried out. And analyzing the product obtained after the catalytic reaction is carried out for 3 hours by using gas chromatography, calculating the conversion rate of the methanol according to the analysis result, and taking the conversion rate as the activity of the silicon-aluminum molecular sieve. Conversion of methanol [ (molar amount of methanol added-molar amount of unreacted methanol)/molar amount of methanol added]X 100%. Wherein the result of 1h is taken as the initial activity.

In the above preferred embodiment, the silicon-aluminum molecular sieve may be a common silicon-aluminum molecular sieve having various topologies, and preferably, the silicon-aluminum molecular sieve is selected from at least one of a silicon-aluminum molecular sieve of MFI structure, a silicon-aluminum molecular sieve of MEL structure, and a silicon-aluminum molecular sieve of BEA structure. More preferably, the silicoaluminophosphate molecular sieve is a silicoaluminophosphate molecular sieve of the MFI structure, such as ZSM-5 molecular sieve.

In the above preferred embodiment, the weight ratio of the second discharging agent, the titanium source, the organic acid, the alkali source and the water is 100: (0.1-10): (0.005-50): (0.5-50): (20-1000), preferably 100: (0.5-10): (1-15): (1-20): (100-800), more preferably the weight ratio of the second discharging agent to the organic acid is 100: (2-8), wherein the second discharging agent is SiO₂The organic acid is counted as H⁺The alkali source is counted as N when the alkali source contains nitrogen element, and the alkali source is counted as OH < - > when the alkali source does not contain nitrogen element. With SiO₂The silicon source is calculated by TiO₂The molar ratio of the titanium source may be (5-20): 1.

in the above preferred embodiment, the step (b) is preferably performed as follows: and mixing the aqueous solution of the alkali source with the second solid, the silicon source and the titanium source, and then performing the fourth heat treatment.

In the preferred embodiment of the above two titanium-silicon-aluminum molecular sieves, the beating is preferably performed at normal temperature and normal pressure. Unless otherwise specified, the heat treatment is generally carried out under autogenous pressure in the case of sealing.

In the above two preferred embodiments of the titanium silicalite molecular sieves, the organic acid is not particularly required, and may be a C1-C10 organic carboxylic acid, preferably at least one of naphthenic acid, peroxyacetic acid and peroxypropionic acid. The concentration of the organic acid solution is preferably >0.1mol/L, more preferably ≥ 1mol/L, still more preferably 2-15 mol/L. In the present disclosure, the main solvent of the acid solution is water, and other solvent additives may also be added as needed. The titanium-silicon-aluminum molecular sieve prepared in the way has better catalytic performance.

In a preferred embodiment of the above two titanium-silicon-aluminum molecular sieves, the silicon source may be an inorganic silicon source and/or an organic silicon source. The inorganic silicon source may be at least one selected from the group consisting of silicate, silica sol, and silica gel. The organic silicon source may be an organic silicate selected from the group consisting of formula I:

in a preferred embodiment of the above two titanium silicalite molecular sieves, the titanium source can be an organic titanium source (e.g., an organic titanate) and/or an inorganic titanium source (e.g., an inorganic titanium salt). Wherein the inorganic titanium source can be TiCl₄、Ti(SO₄)₂、TiOCl₂Titanium hydroxide, titanium oxide, titanium nitrate, titanium phosphate and the like, and the organic titanium source may be at least one of fatty titanium alkoxide and organic titanate. The titanium source is preferably an organic titanium source, and more preferably an organic titanate. The organic titanate is preferably of the formula M₄TiO₄Wherein M is preferably an alkyl group having 1 to 4 carbon atoms, and 4M's may be the same or different, preferably the organotitanate is selected from at least one of isopropyl titanate, n-propyl titanate, tetrabutyl titanate and tetraethyl titanate. Specific examples of the titanium source may be, but are not limited to: TiOCl₂Titanium tetrachloride, titanium sulfate, tetrapropyl titanate (including various isomers of tetrapropyl titanate, such as tetraisopropyl titanate and tetran-propyl titanate), tetrabutyl titanate (various isomers of tetrabutyl titanate, such as tetran-butyl titanate), and tetraethyl titanate.

In a preferred embodiment of the above two titanium silicalite molecular sieves, the type of the alkali source can be selected from a wide range, and can be an organic alkali source and/or an inorganic alkali source, wherein the inorganic alkali source can be ammonia, or an alkali whose cation is an alkali metal or an alkaline earth metal, such as sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, potassium carbonate, barium hydroxide, etc., and the organic alkali source can be one or more of urea, aliphatic amine, aliphatic alcohol amine, and quaternary ammonium alkali compound. The quaternary ammonium base can be various organic quaternary ammonium bases, and the aliphatic amine can be various NH₃In which at least one hydrogen is substituted with an aliphatic hydrocarbon group (preferably an alkyl group), which may be a variety of NH₃Wherein at least one hydrogen is substituted with a hydroxyl-containing aliphatic hydrocarbon group (preferably an alkyl group).

Specifically, the quaternary ammonium base may be a quaternary ammonium base represented by formula II, the aliphatic amine may be an aliphatic amine represented by formula III, and the aliphatic alcohol amine may be an aliphatic alcohol amine represented by formula IV:

in the formula II, R₅、R₆、R₇And R₈Each is C₁-C₄Alkyl of (2) including C₁-C₄Straight chain alkyl of (2) and C₃-C₄Branched alkyl groups of (a), for example: r₅、R₆、R₇And R₈Each may be methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl or tert-butyl.

R⁹(NH₂)_n(formula III);

in the formula III, n is an integer of 1 or 2. When n is 1, R⁹Is C₁～C₆Alkyl of (2) including C₁～C₆Straight chain alkyl of (2) and C₃-C₆Such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, neopentyl, isopentyl, tert-pentyl and n-hexyl. When n is 2, R⁹Is C₁-C₆Alkylene of (2) including C₁～C₆Linear alkylene of (A) and (C)₃～C₆Such as methylene, ethylene, n-propylene, n-butylene, n-pentylene or n-hexylene. More preferably, the aliphatic amine compound is one or more of ethylamine, n-butylamine, butanediamine and hexamethylenediamine

(HOR¹⁰)_mNH_(3-m)(formula IV);

in the formula IVM number of R¹⁰Are the same or different and are each C₁-C₄Alkylene of (2) including C₁-C₄Linear alkylene of (A) and (C)₃-C₄Branched alkylene groups of (a), such as methylene, ethylene, n-propylene and n-butylene; m is 1, 2 or 3. More preferably, the aliphatic alcohol amine compound is one or more of monoethanolamine, diethanolamine and triethanolamine.

Most preferably, the alkali source is at least one selected from the group consisting of sodium hydroxide, aqueous ammonia, ethylenediamine, n-butylamine, butanediamine, hexamethylenediamine, monoethanolamine, diethanolamine, triethanolamine, tetraethylammonium hydroxide, and tetrapropylammonium hydroxide. Wherein, when the alkali source contains ammonia water, the mol ratio of the alkali source includes NH in molecular form₃And NH in ionic form₄ ⁺The presence of ammonia.

In a preferred embodiment of the above two titanium silicalite molecular sieves, the source of alkalinity is preferably provided in the form of an alkaline solution, more preferably the alkaline solution has a pH > 9.

In a preferred embodiment of the above two titanium silicalite molecular sieves, the aqueous solvent is substantially water, and a cosolvent may also be added as needed.

According to the process of the present disclosure, in order to obtain a desired reaction effect, the molar ratio of the propionic acid to the oxidizing agent may be 1: (0.1-5), preferably 1: (0.2-2); the weight ratio of the propionic acid to the catalyst may be (0.1-50): 1.

the oxidizing agent may be any of a variety of materials commonly used in the art capable of oxidizing propionic acid to form peroxypropionic acid in accordance with the methods of the present disclosure. The method disclosed by the invention is particularly suitable for occasions where propionic acid is oxidized by taking peroxide as an oxidizing agent so as to produce the propionic acid peroxide, so that the effective utilization rate of the peroxide can be obviously improved, and the cost for oxidizing the propionic acid is reduced. The peroxide is a compound containing an-O-O-bond in the molecular structure, and can be hydrogen peroxide and/or organic peroxide. The organic peroxide may be at least one selected from the group consisting of t-butyl hydroperoxide, cumene hydroperoxide and cyclohexyl hydroperoxide. Preferably, the oxidizing agent is hydrogen peroxide, which further reduces the separation cost. The oxidizing agent is preferably provided in the form of an aqueous solution.

According to the method of the present disclosure, the reaction may be performed in the presence of a solvent from the viewpoints of further increasing the degree of mixing between reactants in the reaction system, enhancing diffusion, and more conveniently adjusting the severity of the reaction. The kind of the solvent is not particularly limited. In particular, when the titanium-silicon-aluminum molecular sieve prepared by the preparation preferred embodiment of the two titanium-silicon-aluminum molecular sieves in the present disclosure is used as a catalyst for reaction, the addition of the solvent in the reaction is more beneficial to obtain high selectivity of the peroxypropionic acid when the titanium-silicon-aluminum molecular sieve prepared by the second preferred embodiment of the present disclosure is used, compared with the titanium-silicon-aluminum molecular sieve prepared by the first preferred embodiment. Generally, the solvent may be selected from at least one of water, C1-C6 alcohols, C3-C8 ketones, and C2-C6 nitriles. Preferably, the solvent is selected from the group consisting of water, C3-C6 ketones, and C1-C6 alcohols. More preferably, the solvent is at least one selected from the group consisting of methanol, acetone and water. The amount of the solvent to be used is not particularly limited and may be conventionally selected. Generally, the weight ratio of solvent to propionic acid may be (1-100): 1.

according to the method of the present disclosure, the conditions of the reaction may include: the temperature is 0-100 ℃, preferably 20-80 ℃; the pressure is 0.1-3MPa, preferably 0.1-1.5MPa, in terms of gauge pressure; the time is 1-1000min, preferably 2-500 min.

The invention will now be further illustrated by the following examples, without thereby being limited thereto.

In the preparation examples, the X-ray diffraction (XRD) phase diagram of a sample of a titanium silicalite molecular sieve was determined on a Siemens D5005X-ray diffractometer.

In the examples and comparative examples, all the reagents were commercially available.

The composition of the reaction product is analyzed by gas chromatography, and the analysis result is quantified by a correction normalization method. Wherein, the chromatographic analysis conditions are as follows: agilent-6890 type chromatograph, FFAP capillary chromatographic column, sample amount of 0.5 μ L, and sample inlet temperature of 180 deg.C. The column temperature was maintained at 100 ℃ for 2min, then ramped up to 200 ℃ at a rate of 15 ℃/min and maintained for 3 min. FID detector, detector temperature 200 ℃.

In each of the examples and comparative examples:

when the molar ratio of the propionic acid to the oxidant is less than or equal to 1, the relative conversion (%) of the propionic acid is (molar amount of propionic acid in the charge-molar amount of unreacted propionic acid)/molar amount of propionic acid in the charge x 100%;

when the molar ratio of propionic acid to oxidant > 1, the propionic acid relative conversion (%) (molar amount of propionic acid in charge-molar amount of unreacted propionic acid)/molar amount of propionic acid in charge x molar amount of propionic acid in charge/molar amount of oxidant in charge x 100%;

the relative effective utilization (%) of the oxidizing agent ═ molar amount of peroxypropionic acid/(molar amount of added oxidizing agent-molar amount of unreacted oxidizing agent-molar amount of ineffective decomposed oxidizing agent) × 100%;

the peroxypropionic acid selectivity (%) -, is the molar amount of peroxypropionic acid in the product/molar amount of propionic acid total converted x 100%.

Preparation example 1

(1) Taking a TS-1 molecular sieve (prepared by the method described in Zeolite, 1992, Vol.12: 943-950), TiO₂2.1%) was placed in a 100mL slurry bed reactor with continuous feed and membrane separation means, and a mixture of water and 30 wt% hydrogen peroxide (water to hydrogen peroxide volume ratio of 10: 9) a mixture of cyclohexanone and tert-butanol was added at a rate of 10.5mL/h (the volume ratio of cyclohexanone to tert-butanol was 1: 2.5) adding 36 wt% ammonia water at the speed of 5.7mL/h, simultaneously adding the three material flows, continuously discharging at the corresponding speed, maintaining the reaction temperature at 80 ℃, sampling the product every 1h after the reaction is stable, analyzing the composition of a liquid phase by using a gas chromatography, calculating the conversion rate of cyclohexanone by using the following formula, and taking the conversion rate as the activity of the titanium-silicon molecular sieve. Conversion of cyclohexanone [ (molar amount of cyclohexanone charged-molar amount of unreacted cyclohexanone)/molar amount of cyclohexanone charged]X 100%. Measured for the first time, i.e. 1hThe cyclohexanone conversion was its initial activity, which was 99.5%. After a period of about 168 hours, the cyclohexanone conversion rate is reduced from the initial 99.5% to 50%, the catalyst is separated and regenerated by roasting (roasting at 570 ℃ for 4 hours in an air atmosphere), and then the catalyst is continuously used in the cyclohexanone ammoximation reaction, and the step is repeatedly carried out until the activity after regeneration is lower than 50% of the initial activity, at which time, the inactivated ammoximation catalyst sample is used as the discharging agent of the preparation example, and discharging agents SH-1 (the activity is 40%), SH-2 (the activity is 25%) and SH-3 (the activity is 10%) are sequentially obtained according to the method.

(2) Under normal temperature (20 ℃, the same below) and normal pressure (0.1MPa, the same below), firstly mixing and pulping the inactivated cyclohexanone oximation catalyst SH-1 and 1mol/L naphthenic acid aqueous solution, then mixing and stirring the mixed slurry at 45 ℃, and carrying out first heat treatment for 12 hours; after solid-liquid separation, mixing the solid (the relative crystallinity is 71%), silicon source methyl orthosilicate, aluminum source aluminum sulfate, titanium source titanium sulfate and sodium hydroxide aqueous solution (the pH is 12), putting the mixed solution into a stainless steel sealed reaction kettle, and carrying out second heat treatment for 12 hours at 170 ℃, wherein the material composition by mass is the inactivated cyclohexanone oximation catalyst: a titanium source: an aluminum source: acid: alkali: 100 parts of water: 1: 1: 2: 5: 250, deactivated cyclohexanone oximation catalyst with SiO₂Measured as H, acid⁺Calculated as OH, base^-Measured as SiO₂Silicon source and based on TiO₂The molar ratio of the titanium source is 10: 1. and filtering the obtained product, washing with water, drying at 110 ℃ for 120min, and then roasting at 550 ℃ for 3h to obtain the molecular sieve, wherein an XRD (X-ray diffraction) crystal phase diagram of the molecular sieve shows that the titanium-silicon-aluminum molecular sieve (TS-A) with an MFI structure is obtained.

(3) Firstly, mixing and pulping deactivated cyclohexanone oximation catalyst SH-2 and 5mol/L peroxyacetic acid solution at normal temperature and normal pressure, then mixing and stirring the mixed pulp at 20 ℃, and carrying out first heat treatment for 20 hours; after solid-liquid separation, mixing the solid (the relative crystallinity is 89%), silicon source ethyl orthosilicate, aluminum source aluminum sol (the content is 20 weight%), titanium source tetrabutyl titanate and tetrapropyl ammonium hydroxide aqueous solution (the pH is 10), putting the mixed solution into a stainless steel sealed reaction kettle, and carrying out second heat treatment for 20 hours at the temperature of 150 DEG CWherein the mass composition of the materials is that the deactivated cyclohexanone oximation catalyst: a titanium source: an aluminum source: acid: alkali: 100 parts of water: 2: 0.5: 8: 15: 200 deactivated cyclohexanone oximation catalyst with SiO₂Measured as H, acid⁺Calculated as OH, base^-Measured as SiO₂Silicon source and based on TiO₂The molar ratio of the titanium source is 20: 1. and (3) recovering the product according to the method in the step (2) to obtain the titanium-silicon-aluminum molecular sieve, wherein an XRD crystal phase diagram of the titanium-silicon-aluminum molecular sieve shows that the titanium-silicon-aluminum molecular sieve (TS-B) with an MFI structure is obtained.

(4) Under normal temperature and normal pressure, mixing and pulping the inactivated cyclohexanone oximation catalyst SH-3 and 8mol/L aqueous solution of peroxypropionic acid, then mixing and stirring the mixed slurry at 30 ℃, and carrying out first heat treatment for 10 hours; after solid-liquid separation, mixing the solid (the relative crystallinity is 80%), silicon source propyl orthosilicate, aluminum source aluminum hydroxide, titanium source titanium tetrachloride and ethylenediamine aqueous solution (the pH value is 11), putting the mixed solution into a stainless steel sealed reaction kettle, and carrying out second heat treatment for 5 hours at the temperature of 140 ℃, wherein the material quality composition is the inactivated cyclohexanone oximation catalyst: a titanium source: an aluminum source: acid: alkali: 100 parts of water: 5: 2: 5: 5: 150 deactivated cyclohexanone oximation catalyst with SiO₂Measured as H, acid⁺Alkali is calculated as N and SiO₂Silicon source and based on TiO₂The molar ratio of the titanium source is 15: 1. and (3) recovering the product according to the method in the step (2) to obtain the titanium-silicon-aluminum molecular sieve, wherein an XRD crystal phase diagram of the titanium-silicon-aluminum molecular sieve shows that the titanium-silicon-aluminum molecular sieve (TS-C) with an MFI structure is obtained.

(5) Preparing the titanium-silicon-aluminum molecular sieve according to the method in the step (4), except that the temperature of the first heat treatment is 60 ℃, the relative crystallinity of the solid after solid-liquid separation is 65%, and an XRD crystal phase diagram shows that the titanium-silicon-aluminum molecular sieve (TS-D) with an MFI structure is obtained.

(6) Preparing the titanium-silicon-aluminum molecular sieve according to the method in the step (4), except that the temperature of the first heat treatment is 180 ℃, the relative crystallinity of the solid after solid-liquid separation is 95%, and an XRD crystal phase diagram shows that the titanium-silicon-aluminum molecular sieve (TS-E) with an MFI structure is obtained.

(7) Preparing the titanium-silicon-aluminum molecular sieve according to the method in the step (4), except that formic acid is replaced by the peroxopropionic acid aqueous solution, the relative crystallinity of the solid after solid-liquid separation is 60%, and an XRD crystal phase diagram shows that the titanium-silicon-aluminum molecular sieve (TS-F) with an MFI structure is obtained.

(8) Preparing a titanium-silicon-aluminum molecular sieve according to the method in the step (4), except that the deactivated cyclohexanone oximation catalyst: acid 100: 15, the relative crystallinity of the solid after solid-liquid separation is 62%, and an XRD crystal phase diagram shows that the titanium-silicon-aluminum molecular sieve (TS-G) with an MFI structure is obtained.

(9) Preparing the titanium-silicon-aluminum molecular sieve according to the method in the step (4), except that the TS-1 molecular sieve (the relative crystallinity is 100%), aluminum source aluminum hydroxide, titanium source titanium tetrachloride and ethylene diamine aqueous solution are directly mixed for second heat treatment, and an XRD crystal phase diagram shows that the titanium-silicon-aluminum molecular sieve (TS-H) with an MFI structure is obtained.

Preparation example 2

(1) ZSM-5 molecular sieve (prepared by the method described in example 1 of CN 1715185A) is treated with water vapor at 200 deg.C for 10h, then tableted, sieved, and 20-40 mesh particles are loaded into a tubular reaction tube with diameter of 0.8cm and length of 55cm, and the bed volume of catalyst particles is 2.0cm³. The reaction temperature is 300 ℃, the reaction pressure is 1atm, the feeding molar ratio of hydrogen sulfide and methanol is 1:2, and the total gas volume space velocity is 700h^-1Under the conditions of (1), a catalytic reaction for synthesizing dimethyl sulfide is carried out. And analyzing the product obtained after the catalytic reaction is carried out for 3 hours by using gas chromatography, calculating the conversion rate of the methanol according to the analysis result, and taking the conversion rate as the activity of the silicon-aluminum molecular sieve. Conversion of methanol [ (molar amount of methanol added-molar amount of unreacted methanol)/molar amount of methanol added]X 100%. Wherein the initial activity was 99% as the result of 1 h. After a period of about 180 hours, the conversion rate of methanol is reduced from the initial 99% to 50%, the catalyst is separated and regenerated by roasting (roasting at 570 ℃ for 4 hours in air atmosphere), then the catalyst is continuously used in the synthetic reaction of hydrogen sulfide and methanol, the step is repeatedly carried out until the activity after regeneration is lower than 50% of the initial activity, the inactivated catalyst sample is used as the discharging agent of the invention, and the discharging agents SH-I (the activity is 45%), SH-II (the activity is 45%) are obtained in turn according to the method35% for SH-III (15% for activity).

(2) Mixing and pulping the inactivated catalyst SH-I and 1mol/L naphthenic acid aqueous solution at normal temperature (20 ℃, the same below) and normal pressure (0.1MPa, the same below), mixing and stirring the mixed pulp at 50 ℃, and carrying out third heat treatment for 12 hours; after solid-liquid separation, mixing the solid (the relative crystallinity is 70 percent), silicon source methyl orthosilicate, titanium source titanium sulfate and sodium hydroxide aqueous solution (the pH is 12), putting the mixed solution into a stainless steel sealed reaction kettle, and carrying out fourth heat treatment for 12 hours at the temperature of 170 ℃, wherein the material comprises the following components in mass: a titanium source: acid: alkali: 100 parts of water: 1: 2: 5: 250, deactivated catalyst is SiO₂Measured as H, acid⁺Calculated as OH, base^-Measured as SiO₂Silicon source and based on TiO₂The molar ratio of the titanium source is 10: 1. and filtering the obtained product, washing with water, drying at 110 ℃ for 120min, and then roasting at 550 ℃ for 3h to obtain the molecular sieve, wherein an XRD (X-ray diffraction) crystal phase diagram of the molecular sieve shows that the titanium-silicon-aluminum molecular sieve (SA-A) with an MFI structure is obtained.

(3) Mixing and pulping the inactivated catalyst SH-II and 5mol/L peroxyacetic acid solution at normal temperature and normal pressure, mixing and stirring the mixed pulp at 150 ℃, and carrying out third heat treatment for 20 hours; after solid-liquid separation, mixing the solid (the relative crystallinity is 53 percent), silicon source ethyl orthosilicate, titanium source tetrabutyl titanate and tetrapropyl ammonium hydroxide aqueous solution (the pH value is 10), putting the mixed solution into a stainless steel sealed reaction kettle, and carrying out fourth heat treatment for 20 hours at the temperature of 150 ℃, wherein the material comprises the following components in mass percentage: a titanium source: acid: alkali: 100 parts of water: 2: 8: 15: 200 deactivated cyclohexanone oximation catalyst with SiO₂Measured as H, acid⁺Calculated as OH, base^-Measured as SiO₂Silicon source and based on TiO₂The molar ratio of the titanium source is 20: 1. and (3) recovering the product according to the method in the step (2) to obtain the titanium-silicon-aluminum molecular sieve, wherein an XRD crystal phase diagram of the titanium-silicon-aluminum molecular sieve shows that the titanium-silicon-aluminum molecular sieve (SA-B) with an MFI structure is obtained.

(4) Mixing and pulping the inactivated catalyst SH-III and 8mol/L aqueous solution of peroxypropionic acid at normal temperature and normal pressure, and then mixing and stirring the mixed pulp at 100 ℃ for 10 hours; fixing deviceAfter liquid separation, mixing a solid (the relative crystallinity is 61 percent), silicon source propyl orthosilicate, titanium source titanium tetrachloride and ethylenediamine aqueous solution (the pH value is 11), putting the mixed solution into a stainless steel sealed reaction kettle, and carrying out hydrothermal treatment for 5 hours at the temperature of 140 ℃, wherein the material comprises the following components in mass: a titanium source: acid: alkali: 100 parts of water: 5: 5: 5: 150, deactivated catalyst with SiO₂Measured as H, acid⁺Alkali is calculated as N and SiO₂Silicon source and based on TiO₂The molar ratio of the titanium source is 15: 1. and (3) recovering the product according to the method in the step (2) to obtain the titanium-silicon-aluminum molecular sieve, wherein an XRD crystal phase diagram of the titanium-silicon-aluminum molecular sieve shows that the titanium-silicon-aluminum molecular sieve (SA-C) with an MFI structure is obtained.

(5) Preparing the titanium-silicon-aluminum molecular sieve according to the method in the step (4), except that the temperature of the third heat treatment is 40 ℃, the relative crystallinity of the solid after solid-liquid separation is 41%, and an XRD crystal phase diagram shows that the titanium-silicon-aluminum molecular sieve (SA-D) with an MFI structure is obtained.

(6) Preparing the titanium-silicon-aluminum molecular sieve according to the method in the step (4), except that the temperature of the third heat treatment is 180 ℃, the relative crystallinity of the solid after solid-liquid separation is 80%, and an XRD crystal phase diagram shows that the titanium-silicon-aluminum molecular sieve (SA-E) with an MFI structure is obtained.

(7) Preparing the titanium-silicon-aluminum molecular sieve according to the method in the step (4), except that formic acid is replaced by the peroxopropionic acid aqueous solution, the relative crystallinity of the solid after solid-liquid separation is 38%, and an XRD crystal phase diagram shows that the titanium-silicon-aluminum molecular sieve (SA-F) with an MFI structure is obtained.

(8) Preparing a titanium-silicon-aluminum molecular sieve according to the method in the step (4), wherein the difference is that the deactivated catalyst: acid 100: 20, the relative crystallinity of the solid after solid-liquid separation is 30 percent, and an XRD crystal phase diagram shows that the titanium-silicon-aluminum molecular sieve (SA-G) with an MFI structure is obtained.

(9) Preparing the titanium-silicon-aluminum molecular sieve according to the method in the step (4), except that a ZSM-5 molecular sieve (the relative crystallinity is 100 percent), titanium tetrachloride serving as a titanium source and an ethylene diamine aqueous solution are directly mixed for fourth heat treatment, and an XRD crystal phase diagram shows that the titanium-silicon-aluminum molecular sieve (SA-H) with an MFI structure is obtained.

Example 1

Propionic acid, 30 wt% aqueous hydrogen peroxide, solvent methanol and catalyst (TS-A) were charged to A reaction vessel, with A molar ratio of propionic acid to hydrogen peroxide of 1: 1.2, the weight ratio of the propionic acid to the methanol to the catalyst is 8: 50: 1, the reaction is carried out at a temperature of 65 ℃ and a pressure of 0.5 MPa. The results of the reaction for 2 hours and the reaction for 12 hours are shown in Table 1.

Example 2

Peroxypropionic acid was prepared according to the procedure of example 1 except that the solvent methanol was not used in this example. The results of the reaction for 2 hours and the reaction for 12 hours are shown in Table 1.

Example 3

Propionic acid, 30 wt% aqueous hydrogen peroxide and a catalyst (TS-B) were charged to a reaction vessel, with a molar ratio of propionic acid to hydrogen peroxide of 1: 0.6, the weight ratio of propionic acid to catalyst is 15: 1, the reaction is carried out at a temperature of 80 ℃ and a pressure of 1.5 MPa. The results of the reaction for 2 hours and the reaction for 12 hours are shown in Table 1.

Example 4

Propionic acid, 30 wt% aqueous hydrogen peroxide and a catalyst (TS-C) were charged to a reaction vessel at a molar ratio of propionic acid to hydrogen peroxide of 1: 0.2, the weight ratio of propionic acid to catalyst is 25: 1, the reaction is carried out at a temperature of 60 ℃ and a pressure of 1.0 MPa. The results of the reaction for 2 hours and the reaction for 12 hours are shown in Table 1.

Examples 5 to 9

Perpropionic acid was prepared according to the procedure of example 4, except that the catalyst was replaced with TS-D, TS-E, TS-F, TS-G and TS-H, respectively, and the results of the reaction for 2 hours and the reaction for 12 hours are shown in Table 1.

Example 10

Propionic acid, 30 wt% aqueous hydrogen peroxide, solvent methanol and a catalyst (SA-a) were charged into a reaction vessel, and the molar ratio of propionic acid to hydrogen peroxide was 1: 1.5, the weight ratio of the propionic acid to the methanol to the catalyst is 0.1: 10: 1, the reaction is carried out at a temperature of 40 ℃ and a pressure of 0.5 MPa. The results of the reaction for 2 hours and the reaction for 12 hours are shown in Table 1.

Example 11

Peroxypropionic acid was prepared according to the procedure of example 10, except that the solvent methanol was not used in this example. The results of the reaction for 2 hours and the reaction for 12 hours are shown in Table 1.

Example 12

Propionic acid, 30 wt% aqueous tert-butyl hydroperoxide, acetonitrile solvent and a catalyst (SA-B) were charged into a reaction vessel, and the molar ratio of propionic acid to tert-butyl hydroperoxide was 1:2, the weight ratio of the propionic acid to the acetonitrile to the catalyst is 50: 200: 1, the reaction is carried out at a temperature of 40 ℃ and a pressure of 0.5 MPa. The results of the reaction for 2 hours and the reaction for 12 hours are shown in Table 1.

Example 13

Putting propionic acid, cumyl peroxide, solvent acetone and a catalyst (SA-C) into a reaction kettle, wherein the molar ratio of the propionic acid to the cumyl peroxide is 1: and 3, the weight ratio of the propionic acid to the acetone to the catalyst is 5: 500: 1, the reaction is carried out at a temperature of 50 ℃ and a pressure of 2 MPa. The results of the reaction for 2 hours and the reaction for 12 hours are shown in Table 1.

Examples 14 to 18

Perpropionic acid was prepared according to the procedure of example 13, except that the catalyst was replaced with SA-D, SA-E, SA-F, SA-G and SA-H, respectively, and the results of the reaction for 2 hours and the reaction for 12 hours are shown in Table 1.

Example 19

Perpropionic acid was prepared as in example 13, except that the TiSiAl molecular sieve prepared in example 1 of CN102616805A was used as the catalyst, and the results of the reaction were as shown in Table 1 for 2 hours and 12 hours.

Example 20

Perpropionic acid was prepared by following the procedure of example 1 except that the catalyst was replaced with SA-A and the results of the reaction for 2 hours and the reaction for 12 hours are shown in Table 1.

Example 21

Peroxypropionic acid was prepared according to the procedure of example 2, except that the catalyst was replaced with SA-A, and the results of the reaction for 2 hours and the reaction for 12 hours are shown in Table 1.

Comparative example 1

Peroxypropionic acid was prepared according to the procedure of example 1 except that no catalyst was used in this comparative example. The results of the reaction for 2 hours and the reaction for 12 hours are shown in Table 1.

TABLE 1

The above results demonstrate that higher propionic acid conversion, peroxypropionic acid selectivity, and effective oxidant utilization can be achieved by using the disclosed method to prepare peroxypropionic acid. As can be seen by comparing example 1 with comparative example 1, the process of the present disclosure can greatly improve the relative conversion of propionic acid, the relative availability of oxidant, and the selectivity of peroxypropionic acid compared to when no catalyst is used. As can be seen from the comparison between examples 1 to 4 and examples 5 to 9, and between examples 10 to 13 and examples 14 to 18, the titanium-silicon-aluminum molecular sieve prepared by the preferred preparation method of titanium-silicon-aluminum molecular sieve disclosed by the disclosure is beneficial to further improving the relative conversion rate of propionic acid, the selectivity of peroxypropionic acid and the relative effective utilization rate of oxidant when used for reaction. As can be seen from a comparison of examples 1-4 and examples 10-13, and in particular from a comparison of examples 1-2 with examples 20-21, the addition of solvent is more beneficial to achieve higher relative propionic acid conversion, oxidant utilization, and peroxypropionic acid selectivity when reacting with the titanium silicalite molecular sieves produced according to the second preferred embodiment of the present disclosure, as compared to the titanium silicalite molecular sieves produced according to the first preferred embodiment of the present disclosure.

The preferred embodiments of the present disclosure have been described in detail above, however, the present disclosure is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present disclosure within the technical idea of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

It should be noted that, in the foregoing embodiments, various features described in the above embodiments may be combined in any suitable manner, and in order to avoid unnecessary repetition, various combinations that are possible in the present disclosure are not described again.

In addition, any combination of various embodiments of the present disclosure may be made, and the same should be considered as the disclosure of the present disclosure, as long as it does not depart from the spirit of the present disclosure.

Claims

1. A process for preparing peroxypropionic acid, comprising: carrying out contact reaction on propionic acid and an oxidant in the presence of a catalyst, wherein the catalyst is a titanium-silicon-aluminum molecular sieve catalyst;

the reaction is carried out in the presence of a solvent, wherein the weight ratio of the solvent to the propionic acid is (1-100): 1, the solvent is at least one selected from water, C1-C6 alcohol, C3-C8 ketone and C2-C6 nitrile;

the preparation steps of the titanium-silicon-aluminum molecular sieve comprise:

2. The process of claim 1, wherein the titanium silicalite molecular sieve is at least one selected from the group consisting of a titanium silicalite molecular sieve of the MFI structure, a titanium silicalite molecular sieve of the MEL structure, a titanium silicalite molecular sieve of the BEA structure, a titanium silicalite molecular sieve of the MWW structure, a titanium silicalite molecular sieve of the MOR structure, a titanium silicalite molecular sieve of the TUN structure, and a titanium silicalite molecular sieve of the two-dimensional hexagonal structure.

3. The method of claim 1, wherein the weight ratio of the first discharging agent, the titanium source, the aluminum source, the organic acid, the alkali source, and the water is 100: (0.1-10): (0.1-10): (0.005-50): (0.5-50): (20-1000), the first discharging agent is SiO₂The organic acid is counted as H⁺The alkali source is counted as N when containing nitrogen element, and the alkali source is counted as OH when not containing nitrogen element^-Counting; with SiO₂The silicon source is calculated by TiO₂The molar ratio of the titanium source is (5-20): 1; the concentration of the organic acid solution is more than 0.1 mol/L.

4. The method according to claim 1, wherein the discharging agent of the reaction device using the titanium silicalite molecular sieve as the catalyst active component in the step (1) is at least one selected from the group consisting of a discharging agent of an ammoximation reaction device, a discharging agent of a hydroxylation reaction device and a discharging agent of an epoxidation reaction device.

5. The process of claim 4, wherein the titanium silicalite molecular sieves in step (1) are of the MFI structure and the activity of the first discharge agent is less than 50% of the activity of the titanium silicalite molecular sieves when fresh.

6. The method according to claim 4, wherein in the step (2), the aluminum source and the alkali source are mixed in the presence of an aqueous solvent to obtain a mixed solution, and then the second heat treatment is performed after the mixed solution is mixed with the first solid and the titanium source.

7. The method of claim 1, wherein the weight ratio of the second discharging agent, the titanium source, the organic acid, the alkali source, and the water is 100: (0.1-10): (0.005-50): (0.5-50): (20-1000), the second discharging agent is SiO₂The organic acid is counted as H⁺The alkali source is counted as N when containing nitrogen element, and the alkali source is counted as OH when not containing nitrogen element^-Counting; with SiO₂The silicon source is calculated by TiO₂The molar ratio of the titanium source is (5-20): 1; the concentration of the organic acid solution is more than 0.1 mol/L.

8. The method of claim 1, wherein the discharging agent of the reaction device with the silicon-aluminum molecular sieve as the catalyst active component in the step a is the discharging agent of a synthesis reaction device of hydrogen sulfide and methanol.

9. The process of claim 8, wherein the silicoaluminophosphate molecular sieve in step a is a silicoaluminophosphate molecular sieve of the MFI structure, and the activity of the second discharge agent is less than 50% of the activity of the silicoaluminophosphate molecular sieve when fresh.

10. The method according to claim 1, wherein the organic acid is at least one selected from the group consisting of naphthenic acid, peracetic acid, and propionic acid; the alkali source is at least one selected from ammonia, aliphatic amine, aliphatic alcohol amine and quaternary ammonium base; the aluminum source is at least one selected from aluminum sol, aluminum salt, aluminum hydroxide and aluminum oxide; the titanium source is inorganic titanium salt and/or organic titanate; the silicon source is organosilicate.

11. The process of claim 1, wherein the molar ratio of propionic acid to oxidant is 1: (0.1-5); the weight ratio of the propionic acid to the catalyst is (0.1-50): 1; the oxidant is at least one selected from hydrogen peroxide, tert-butyl hydroperoxide, cumyl peroxide and cyclohexyl hydroperoxide; the reaction conditions include: the temperature is 0-100 deg.C, and the pressure is 0.1-3 MPa.

12. The process of claim 11, wherein the molar ratio of propionic acid to oxidant is 1: (0.2-2).