CN117466698A

CN117466698A - Alkyne selective hydrogenation method

Info

Publication number: CN117466698A
Application number: CN202210850118.8A
Authority: CN
Inventors: 谭都平; 谢元; 董正平; 李保江; 李蓬勃; 张生芳; 康龙; 彭远嘱; 胥昌平; 向永生
Original assignee: Petrochina Co Ltd
Current assignee: Petrochina Co Ltd
Priority date: 2022-07-19
Filing date: 2022-07-19
Publication date: 2024-01-30

Abstract

The invention discloses an alkyne selective hydrogenation method, wherein in the alkyne selective hydrogenation method, the inlet temperature of a hydrogenation reactor is 45-80 ℃, the pressure is 1.5-3.0 MPa, and the gas volume space velocity is 2000-6000 h ^‑1 The method comprises the steps of carrying out a first treatment on the surface of the The catalyst used in the alkyne selective hydrogenation reaction: the carrier isAlumina or mainly alumina, the specific surface area of the catalyst is 15-40 m ² /g; the active component at least contains Pd and Ag, the mass content of Pd is 0.02-0.04% and the mass content of Ag is 0.03-0.015% calculated by taking the mass of the carrier as 100%, the active component palladium is loaded in an organic cage, the organic cage is positioned on the outer surface of the catalyst, and the size of the organic cage is 1.4-2.6 nm. The invention synthesizes an organic cage structure with specific size on a carrier, so that the active component palladium is loaded in the organic cage, and the maximum size of an active center (cluster) formed by palladium is the size of the cage under the limitation of the physical size of the organic cage. And the size meets the requirements of acetylene selectivity and activity, and reduces the generation probability of side reactions.

Description

Alkyne selective hydrogenation method

Technical Field

The invention relates to a method for selecting alkyne with two carbon fractions, in particular to a method for selecting hydrogenation by a two-carbon post-hydrogenation process.

Background

Petroleum hydrocarbon, such as ethane, naphtha, diesel oil, hydrogenated tail oil, etc. is steam cracked to obtain ethylene containing acetylene in 0.2-2.5 wt%. When used in polymerization, acetylene in ethylene reduces the activity of the polymerization catalyst and affects the physical properties of the polymer, and must therefore be removed. At present, a selective hydrogenation method is generally adopted in industry to remove acetylene in ethylene, and the adopted catalyst is mainly noble metal catalyst such as Pd, pt, au and the like. In order to ensure that ethylene generated by acetylene hydrogenation and original ethylene in raw materials are not continuously hydrogenated to generate ethane, so that ethylene loss is caused, the higher hydrogenation selectivity of the catalyst is ensured, and better economic benefit can be obtained.

The second-carbon hydrogenation is to calculate the needed hydrogen according to the content of acetylene and match the hydrogen with hydrogenation materials, the mole ratio of the hydrogen to the acetylene is generally not more than 2, and the hydrogen is less, so that the dimerization reaction of the acetylene is easy to occur, the fourth-carbon fraction is generated, and the fourth-carbon fraction is further polymerized to generate an oligomer with wider molecular weight, commonly called as green oil. Green oil adsorbs on the catalyst surface and further forms coke, blocking catalyst pore channels, preventing the reactant from diffusing to the surface of the active center of the catalyst, thereby causing the activity of the catalyst to be reduced.

The noble metal catalyst has higher activity, but green oil is easy to generate in the use process, so that the catalyst is coked and deactivated, and the stability and the service life of the catalyst are affected. Patent CN200810119385.8 discloses a non-noble metal supported selective hydrogenation catalyst and a preparation method and application thereof, wherein the catalyst comprises a carrier, and a main active component and a co-active component supported on the carrier, wherein the main active component is Ni, the co-active component is at least one selected from Mo, la, ag, bi, cu, nd, cs, ce, zn and Zr, the main active component and the co-active component exist in an amorphous form, the average particle diameter is less than 10nm, and the carrier is a porous material without oxidizing property; and the catalyst is prepared by a micro-emulsification method.

US4404124 prepares a selective hydrogenation catalyst with active component shell distribution by a step-by-step impregnation method, and can be applied to selective hydrogenation of carbon two fractions to eliminate acetylene in ethylene. US5587348 uses alumina as a carrier, adds promoter silver and palladium, and adds fluorine chemically bonded with alkali metal to prepare a carbon hydrogenation catalyst with excellent performance. The catalyst has the characteristics of reducing green oil generation, improving ethylene selectivity and reducing the generation amount of oxygen-containing compounds.

Patent CN1736589 reports a Pd/gamma-Al prepared by a complete adsorption impregnation method ₂ O ₃ And a hydrogenation catalyst is selected, and the green oil is produced in a large amount in the use process of the catalyst. Patent CN200810114744.0 discloses an unsaturated hydrocarbon selective hydrogenation catalystA preparation method thereof. The catalyst takes alumina as a carrier and palladium as an active component, and the rare earth, alkaline earth metal and fluorine are added to improve the impurity resistance and coking resistance of the catalyst, but the selectivity of the catalyst is not ideal.

The catalyst prepared by the method adopts the catalyst with single pore diameter distribution, and the catalyst selectivity is poor under the influence of internal diffusion in the fixed bed reaction process. The carrier with double-peak pore distribution ensures high activity of the catalyst, and the existence of macropores can reduce the influence of internal diffusion and improve the selectivity of the catalyst. ZL971187339 discloses a hydrogenation catalyst, wherein the carrier is a honeycomb carrier, and is a large-aperture carrier, so that the selectivity of the catalyst is effectively improved. CN1129606a discloses a hydrocarbon conversion catalyst, the carrier catalyst of which comprises alumina, nickel oxide, iron oxide, etc., and the catalyst comprises two kinds of pores, one of which is used for improving the catalytic reaction surface, and the other is beneficial to diffusion. Patent CN101433842a discloses a hydrogenation catalyst, which has a bimodal pore distribution, the most probable radius of the small pore portion is 2-50 nm, the most probable radius of the large pore portion is 100-500 nm, and the catalyst has good hydrogenation activity and good selectivity and large ethylene increment at the same time of the bimodal pore distribution.

In the carbon di-hydrogenation reaction, green oil generation and catalyst coking are important factors affecting catalyst service life. The activity, selectivity and service life of the catalyst form the overall performance of the catalyst, and the methods listed above either provide a better approach to improving the activity and selectivity of the catalyst, but do not solve the problem that the catalyst is easy to coke, or solve the problem that the catalyst is easy to generate green oil and coke, but do not solve the problem of selectivity. The carrier with a macroporous structure can improve the selectivity, but larger molecules generated by polymerization and chain growth reaction are easy to accumulate in macropores of the carrier, so that the catalyst is coked and deactivated, and the service life of the catalyst is influenced.

201910988247.1A selective hydrogenation process for preparing catalyst features that the carrier of catalyst is in bimodal pore distribution, and in the course of preparing said catalyst, 2 approaches are used to load active components, and part of Pd is loaded in small pores by solution method to become active component for main reaction. In addition, the W/O microemulsion with the particle size larger than that of the carrier pores is prepared, the microemulsion contains metal salts of nickel and copper, and the components are distributed in the carrier macropores to form Ni-Cu active centers.

The catalyst prepared by the method ensures that the selective hydrogenation reaction is mainly carried out on small holes, green oil generated by the reaction enters large holes and is subjected to saturated hydrogenation on Ni-Cu active centers, and the coking amount of the catalyst is reduced. Although this method can reduce the coking rate of the catalyst, it does not solve the problem of byproduct formation.

In the carbon two selective hydrogenation reaction, pd is used as the main active component, and Pd is used as Pd in the traditional impregnation preparation process of the catalyst ²⁺ Or [ PdCl ] ₄ ] ^2- The ionic species is bound to the support and during activation Pd aggregates to become active sites. Due to the aggregation of Pd during activation, it is a kinetic-governed random process, that is, the size of each active center is difficult to control in advance.

Previous studies have found a selective hydrogenation process for acetylene which is: first one acetylene molecule is combined with 1 hydrogen atom to form vinyl, which is then combined with a hydrogen atom to form ethylene, or 2 vinyl groups are coupled to form butadiene. Since butadiene can undergo a series of polymerization reactions to form green oil and then coke, inhibition of butadiene formation becomes a key to preventing coking of the carbon two selective hydrogenation catalyst.

It is apparent that if 2 vinyl groups are formed simultaneously at 1 catalyst activity center, the probability of butadiene formation increases greatly. It was also found that the large size of the active center increases the yield of butadiene. To prevent large active center sizes, there are generally 2 approaches: one is to reduce the amount of active ingredient and the other is to enlarge the dispersion area of the active ingredient. However, the load of the active components is reduced, the number of active centers is possibly insufficient, the hydrogenation activity is insufficient, acetylene cannot be completely removed, and the hydrogenation product is unqualified; the expansion of the active component loading area, the active center with part not located near the catalyst surface, results in poor catalyst selectivity and great ethylene loss in the hydrogenation process.

In order to reduce the generation of green oil in the carbon di-hydrogenation process, it is critical to prevent the formation of 2 or more vinyl groups simultaneously on one active center, and for this reason, many noble metal single-atom catalysts have been studied in the hydrogenation reaction, but there is a considerable distance between these studies and practical applications from the present point of view. The reason for this is: in the active center of hydrogenation reaction, 2 processes need to be completed, wherein 1 is the activation of alkyne molecules, namely electron pairs of alkyne molecules double bonds enter into empty orbitals of active center atoms, and the active center atoms feed back the electron pairs to the opposite bond orbitals of alkyne molecules, so that double bond energy is reduced, double bonds are activated, and breakage occurs; at the same time, the same process is required for hydrogen molecules to activate hydrogen into hydrogen atoms. For a single-atom active center, the physical size of a single atom is limited, and meanwhile, the 2 processes are difficult to finish, so that the reaction process is slower, and the requirements of practical application are difficult to meet. Therefore, it is a natural matter that the activity neutrality needs to have a certain physical size, and in fact, for the palladium catalyst, since a large amount of hydrogen can be absorbed inside the stacked structure, the activation of hydrogen and the transfer of hydrogen atoms are completed inside the stacked structure of palladium, and thus the activity is higher than that of the active component capable of adsorbing hydrogen only on the surface.

In order to prepare catalysts with narrow particle size distribution, some researchers have synthesized a series of organic cages with three-dimensional structures, which have fixed sizes and can be used for fixing metals, thereby preparing catalysts with highly dispersed metal clusters. Qiang Song et al synthesized an organic Three-dimensional organic cage, three-dimensional hydrophobic porous organic polymers confined Pd nanoclusters for phase-transfer catalytic hydrogenation of nitroarenes in water. The hydrogenation of organocage supported metallic palladium for nitrobenzene is reported herein. At present, the three-dimensional organic cages are used for full hydrogenation or homogeneous hydrogenation after being loaded with active components and uniformly distributed on a carrier in a solution. For selective hydrogenation, not only the size of the active center has an influence on the reaction, but also the distribution of the active components in the catalyst has a great influence on the reaction result, so that the catalyst prepared by the organic cage and with uniformly distributed active components is not suitable for selective hydrogenation, especially for selective hydrogenation of acetylene.

Disclosure of Invention

The invention mainly aims to provide an alkyne selective hydrogenation method, which overcomes the defects of low activity, poor selectivity, easy coke formation and the like of a catalyst for alkyne selective hydrogenation in the prior art.

In order to achieve the aim, the invention provides an alkyne selective hydrogenation method, wherein in the alkyne selective hydrogenation method, the inlet temperature of a hydrogenation reactor is 45-80 ℃, the pressure is 1.5-3.0 MPa, and the gas volume space velocity is 2000-6000 h ^-1 The method comprises the steps of carrying out a first treatment on the surface of the The catalyst used in the alkyne selective hydrogenation reaction: the carrier is alumina or alumina mainly, the specific surface area of the catalyst is 15-40 m ² /g; the active components are Pd and Ag, the mass content of Pd is 0.02-0.04% and the mass content of Ag is 0.03-0.015% calculated by taking the mass of the carrier as 100%, the active component palladium is loaded in an organic cage, the organic cage is positioned on the outer surface of the catalyst, and the size of the organic cage is 1.4-2.6 nm.

The alkyne selective hydrogenation method provided by the invention is characterized in that the hydrogenation reactor is an adiabatic reactor or an isothermal reactor; the hydrogenation reactor is a one-stage reactor or a two-stage reactor.

The alkyne selective hydrogenation method comprises the steps that a hydrogenation material is a carbon two fraction, the carbon two fraction enters a reactor for gas-phase hydrogenation to remove acetylene, the ethylene volume content in the carbon two fraction is 60-90%, and the acetylene volume content is 0.1-1.0%.

According to the alkyne selective hydrogenation method, when the reactor is a fixed bed one-stage reactor, the mole ratio of hydrogen to alkyne at the inlet of the reactor is 1.3-2.0, and the volume content of acetylene at the inlet of the reactor is 0.1-0.8%;

or the reactor is a fixed bed two-stage reactor, the mole ratio of hydrogen to alkyne at the inlet of the first-stage reactor is 1.1-1.3, the mole ratio of hydrogen to alkyne at the inlet of the second-stage reactor is 1.4-2.0, and the volume content of acetylene at the inlet of the first-stage reactor is 0.7-1.5%;

or the reactor is a fixed bed three-stage reactor, the mole ratio of hydrogen/alkyne at the inlet of the first-stage reactor is 0.9-1.3, the mole ratio of hydrogen/alkyne at the inlet of the second-stage reactor is 1.1-1.5, the mole ratio of hydrogen/alkyne at the inlet of the three-stage reactor is 1.5-2.0, and the volume content of acetylene at the inlet of the first-stage reactor is 1.0-2.0%.

The invention discloses an alkyne selective hydrogenation method, wherein the preparation method of the catalyst comprises the following steps:

(1) Synthesizing hydrophilic organic polymer in the carrier, wherein the polymer occupies 80-100% of the total pore volume, preferably 85-95%, to obtain a semi-finished catalyst A;

(2) Synthesizing an organic cage in the rest outer holes of the carrier to obtain a semi-finished catalyst B;

(3) Dissolving an organic palladium compound in halogenated ethane to obtain a palladium precursor solution;

(4) Immersing the semi-finished catalyst B into an alcohol solution, dripping the palladium precursor solution prepared in the step (3) into a mixture of the semi-finished catalyst B and alcohol, adding a reducing agent for reduction after an organic palladium compound is deposited in an organic cage, and roasting at a temperature at which a hydrophilic organic polymer can be decomposed after separation and drying to obtain a semi-finished catalyst C;

(5) Dissolving soluble silver salt in deionized water or organic solution to obtain silver impregnating solution, immersing semi-finished catalyst C in the silver impregnating solution, adding reducing agent to reduce silver to obtain the reduced catalyst,

or drying and roasting to obtain the oxidation state catalyst.

The technical principle is as follows:

in the step (1), when the carrier is mixed with small molecule hydrophilic organic matters such as lactic acid and the like, the small molecules are combined with polar groups on the surface of alumina and adsorbed on the carrier; if the volume of the hydrophilic organic matters is smaller than the pore volume of the carrier, the organic small molecules are adsorbed in the inner pores; after heating, the hydrophilic organic matter is polymerized or condensed, and the formed polymer is difficult to move in the carrier, so that the outer surface of the carrier is exposed.

Mixing tri (4-formylphenyl) amine and aromatic diamine with the carrier with the exposed outer surface, and synthesizing an organic cage with a certain space size on the outer surface of the carrier under the action of a catalyst, wherein the size of the organic cage mainly depends on the molecular size of the monomer aromatic diamine; the number of organic cages is mainly determined by the number and relative proportion of the 2 monomers.

After the organic cage synthesis, the organic palladium compound solution is mixed with the carrier carrying the organic cage, and the non-benign solvent of the organic palladium compound is gradually added. The organic palladium compound gradually deposits in the synthesized organic cage; and then the palladium atoms form aggregates in the organic cage through liquid phase reduction. The amount of palladium supported in each organic cage at this time. Depending on the total amount of palladium and the relative amount of organic cages.

And (3) heating the obtained semi-finished catalyst containing palladium at a certain temperature to decompose the synthetic polymer in the step (1) to obtain the semi-finished catalyst with palladium supported on the outer shell layer of the catalyst. The structure of the organic cage belongs to an imine structure, the heat resistance is far higher than that of common organic polymers, the heat resistance temperature can reach more than 450 ℃, and polymers such as polylactic acid, polyacrylic acid and the like are completely decomposed below 420 ℃, so that the catalyst with palladium loaded in the organic cage of the outer layer of the catalyst can be obtained by heating at 420 ℃.

Loading palladium-containing semi-finished catalyst in silver-containing solution, reducing to obtain reduced palladium/silver catalyst,

if calcined at high temperature, the silver-containing precursor is oxidatively decomposed to give an oxidized palladium/silver catalyst.

Thus, the detailed preparation process of the catalyst of the invention is:

(1) Mixing hydrophilic polymerizable monomer with the roasted carrier, and polymerizing at a certain temperature to obtain a semi-finished catalyst A;

(2) Mixing tri (4-formylphenyl) amine and halogenated acetic acid, dissolving in halogenated acetic acid, then mixing with a semi-finished catalyst A, stirring and dropwise adding a mixed solution of aromatic diamine substituent and halogenated acetic acid, standing the mixture, pouring out residual liquid after the reaction is complete, washing with alcohol and deionized water respectively, and drying to obtain a semi-finished catalyst B;

(3) Dissolving an organic palladium compound in halogenated ethane to obtain a palladium precursor solution for later use;

(4) Immersing the semi-finished catalyst B in an alcohol solution, dropwise adding a palladium precursor solution into a mixture of the semi-finished catalyst B and alcohol, stirring at the same time, dropwise adding a reducing agent, heating and stirring until the surface of the semi-finished catalyst B is not discolored, pouring the solution, washing with deionized water, drying, and roasting at a temperature at which an organic polymer can be decomposed to obtain a semi-finished catalyst C;

(5) Dissolving soluble silver salt in deionized water or organic solution to obtain silver impregnating solution, immersing the semi-finished catalyst C in the silver impregnating solution, standing after the semi-finished catalyst C is fully absorbed, and drying; reducing agent is dripped to reduce silver, the solution is poured off, deionized water is used for washing, and drying is carried out, so that the reduction catalyst is obtained;

Alternatively, the oxidation catalyst is obtained by pouring out the solution without reduction, washing with deionized water, drying, and calcining.

Wherein the aromatic diamine compound is diphenyl diamine, terphenyl diamine, diphenyl diamine with substituent on benzene ring or terphenyl diamine with substituent on benzene ring. Preferably, the p-phenylenediamine has a substituent on its benzene ring.

The alkyne selective hydrogenation method of the invention, wherein, the volume of the hydrophilic polymerizable monomer polymerized in the step 1 is 80-100% of the pore volume of the carrier, preferably 85-95%; in the step 2, the reaction of the tri (4-formylphenyl) amine and the aromatic diamine compound is carried out under the catalysis of halogenated acetic acid, and the molar ratio of the aromatic diamine compound to the tri (4-formylphenyl) amine is 1.2-2.0: 1, a step of; in the step 3, the mass ratio of palladium to tri (4-formylphenyl) amine contained in the organic palladium compound is 0.63-4.8:1;

the kind of the hydrophilic polymerizable monomer in the step 1 is not particularly limited in the present invention, and the hydrophilic polymerizable monomer of the present invention may be polymerized or condensed at a temperature of less than 420℃and may be decomposed at a temperature of less than 450℃after the polymerization of the hydrophilic polymerizable monomer. The hydrophilic polymerizable monomer contains a carbonyl group, a carboxyl group, or a carbon-carbon double bond, and the hydrophilic polymerizable monomer may undergo a polymerization reaction or a condensation reaction, for example, and the hydrophilic polymerizable monomer may be lactic acid or acrylic acid, for example.

In step 1, a certain temperature refers to the temperature at which the hydrophilic polymerizable monomer undergoes condensation reaction or polymerization reaction, and varies with the monomers. The polymerization temperature in the embodiment of the invention is 80-200 ℃, and the invention is not particularly limited to the polymerization time.

In the step 2, the aromatic diamine compound is diphenyl diamine, terphenyl diamine, diphenyl diamine with substituent on benzene ring or terphenyl diamine with substituent on benzene ring, and the substituent is alkyl or halogen. Wherein alkyl is for example having 1-10 carbons. The biphenyldiamine and the terphenyldiamine may be 2,2' -biphenyldiamine, 3' -biphenyldiamine, 3,4' -biphenyldiamine, 2,4' -biphenyldiamine, 4' -diaminotriphenylene, etc., and the present invention is not particularly limited, but p-biphenyldiamine and terphenylphenylenediamine are preferable. Haloacetic acid is a catalyst for the reaction of tris (4-formylphenyl) amine and aromatic diamine compounds, such as fluoro or chloroacetic acid, more such as trifluoroacetic acid or dichloroacetic acid; the haloalkane is a solvent, which may be fluoro, chloro or bromo alkane, which may be halomethane or ethane, preferably dichloroethane or trichloromethane. In another embodiment, the mass ratio of tris (4-formylphenyl) amine to haloacetic acid is, for example, 2000 to 6000:1.

Further, the tri (4-formylphenyl) amine and aromatic diamine compound of the present invention react, that is, formyl groups on benzene rings and amino groups of aromatic hydrocarbons can undergo condensation reaction to form imino groups, and as the monomer is tri (4-formylphenyl) amine, three formyl groups on benzene rings can react with three aromatic diamine molecules, and the other end of aromatic diamine molecules can react with tri (4-formylphenyl) amine again, as the tri (4-formylphenyl) amine has three active groups, a cross-linked structure can be formed, and imino non-linear molecules finally form a large organic molecule with a network (cross-linked) and cage-shaped space structure.

The alkyne selective hydrogenation method provided by the invention, wherein the organic palladium compound is palladium acetate or palladium acetylacetonate; the silver-containing compound is a soluble silver salt; the reducing agent is methanol, formaldehyde, formic acid, ethanol, acetaldehyde or hydrazine hydrate.

The invention has the beneficial effects that:

1. the invention synthesizes an organic cage structure with specific size on a carrier, so that the active component palladium is loaded in the organic cage, and the maximum size of an active center (cluster) formed by palladium is the size of the cage under the limitation of the physical size of the organic cage. While this size meets the acetylene selectivity and activity requirements, the chance of simultaneously forming 2 vinyl groups in one active center is greatly reduced.

2. Further, when the catalyst is prepared, firstly, an organic polymer is synthesized, the inner hole of the carrier is closed, and an organic cage is synthesized at the outer hole of the carrier, so that the active component palladium is loaded on the outer surface of the catalyst, and then the organic polymer is baked to obtain the catalyst. The gas phase hydrogenation reaction is an internal diffusion limiting reaction, the organic cage structure is positioned on the outer surface of the catalyst, the influence of the internal diffusion limiting on the catalytic reaction is avoided, and the selectivity of the catalyst is good.

3. Further, the active component silver can form an alloy with the active component palladium, ag atoms can play a role in separating Pd atoms, so that the space distance of the adsorbed acetylene molecules is increased, the mutual distance between the corresponding reaction intermediates after acetylene hydrogenation is also larger, and intermediate coupling is not easy to occur, thereby reducing the formation of green oil and improving the selectivity of acetylene hydrogenation.

4. When the catalyst is used for carrying out selective hydrogenation reaction of alkyne, byproducts are greatly reduced, so that the catalyst does not need to be regenerated. In addition, even if the catalyst of the invention needs to be regenerated, the catalyst can be regenerated at a temperature lower than 450 ℃ without damaging the organic cage structure, so that the service life of the catalyst can be greatly prolonged.

Detailed Description

The following embodiments are provided by carrying out the embodiments of the present invention on the premise of the embodiments of the present invention, and the detailed implementation process is given, but the scope of the present invention is not limited to the following embodiments, and the following embodiments do not specify specific conditions, structures or experimental methods, and generally follow conventional conditions.

The catalyst of the invention adopts the following characterization method in the preparation process:

BET meter, american microphone, measures specific surface area and pore size distribution.

And (3) measuring the content of Pd and Ag in the catalyst by using an A240FS atomic absorption spectrometer.

Agilent 7890A gas chromatograph, measuring reactor outlet, inlet hydrogen and acetylene content and butene content.

The catalyst weight was measured on a 0.1mg electronic balance.

Raw materials: tris (4-formylphenyl) amine, dichloroacetic acid, dichloroethane, biphenyldiamine, hydrazine hydrate, ethanol, methanol, acetic acid, formic acid, formaldehyde, lactic acid, acrylic acid, palladium acetate, palladium acetylacetonate, silver nitrate, analytically pure, shanghai national pharmaceutical group company; alumina, shandong aluminum products group Co.

Example 1

Catalyst carrier: a commercially available spherical alumina carrier was used, 4mm in diameter. After roasting for 4 hours at 1050 ℃, the pore volume is 0.6m ³ Per gram, specific surface area 40.15m ² And/g. 100g of the carrier was weighed.

And (3) preparing a catalyst:

(1) Weighing 76.8g of lactic acid, mixing with 100g of roasted carrier, and keeping the temperature at 160 ℃ for 10 hours to obtain a semi-finished catalyst A;

(2) Mixing 6.7mg of tris (4-formylphenyl) amine with 0.0033mg of dichloroacetic acid, dissolving in 50ml of dichloroethane, then mixing with a semi-finished catalyst A, stirring, dropwise adding a mixed solution of 4.5mg of p-phenylenediamine and 10ml of dichloroethane, standing the mixture at room temperature for 200 hours, pouring out residual liquid, washing with ethanol and deionized water respectively, and drying to obtain a semi-finished catalyst B;

(3) Palladium acetate 0.053g was dissolved in 50mL glacial acetic acid and the palladium acetate was completely dissolved for further use.

(4) Immersing the semi-finished catalyst B in 50mL of ethanol solution, dripping the solution prepared in the step (3) into a mixture of the carrier and ethanol, and stirring for 30 hours. Then, 20ml of formaldehyde solution was added dropwise to the above solution, stirred at 70℃for 1 hour, poured off, washed with deionized water, dried at 120℃and calcined at 240℃for 8 hours to give a semi-finished catalyst C.

(5) 0.047g of silver nitrate is weighed and dissolved in 57g of deionized water, the semi-finished catalyst C is immersed in the prepared solution, after the solution is completely absorbed, the solution is kept stand for 4 hours, then 5ml of 5wt% hydrazine hydrate solution is added into the solution (mixture) in a dropwise manner, the solution is stirred for 1 hour at room temperature, the solution is poured off, washed by the deionized water and dried at 120 ℃ to obtain the required catalyst.

The catalyst prepared by atomic absorption spectrometry gave a Pd content of 0.025% and an Ag content of 0.03% in the catalyst of example 1.

Comparative example 1

Catalyst carrier: the carrier of example 1 was used and the procedure was the same. The difference is that there is no step (1) in the implementation

And (3) preparing a catalyst:

(1) 6.7mg of tri (4-formylphenyl) amine and 0.0033mg of dichloroacetic acid are mixed and dissolved in 50ml of dichloroethane, then the mixture is mixed with a semi-finished catalyst A, a mixed solution of 4.5mg of p-phenylenediamine and 10ml of dichloroethane is stirred and added dropwise, the mixture is stood for 200 hours at room temperature, residual liquid is poured out, and the residual liquid is washed with ethanol and deionized water respectively and dried to obtain a semi-finished catalyst A1;

(2) Palladium acetate 0.053mg was dissolved in 50ml glacial acetic acid and the palladium acetate was completely dissolved for further use.

(3) The semi-finished catalyst A1 was immersed in 50ml of an ethanol solution, and the solution prepared in step (2) was added dropwise to a mixture of the support and ethanol while stirring for 30 hours. Then, 20ml of formaldehyde solution was added dropwise to the above solution, stirred at 70℃for 1 hour, the solution was decanted, washed with deionized water, dried at 120℃and calcined at 240℃for 8 hours to obtain a semi-finished catalyst B1.

(4) Weighing 0.047g of silver nitrate, dissolving the silver nitrate into 57g of deionized water, immersing the semi-finished catalyst B1 into the prepared solution, standing for 4 hours after the solution is completely absorbed, then dropwise adding 5ml of 5wt% hydrazine hydrate solution into the solution, stirring for 1 hour at room temperature, pouring out the solution, washing with deionized water, and drying at 120 ℃ to obtain the comparative catalyst 1.

The catalyst prepared by atomic absorption spectrometry was found to give a catalyst of comparative example 1 having a Pd mass content of 0.025% and an Ag mass content of 0.03%.

Effect of the invention

The process conditions are as follows: the space velocity of the material is 3000/h, the operating pressure is 1.5MPa, the inlet temperature of the reactor is 45 ℃, and the catalyst loading is 200mL.

The hydrogenated materials are composed of:

acetylene 0.1% (v/v), ethylene 60% (v/v), carbon three 0.5% (v/v), hydrogen/alkyne 1.5 (v/v).

Table 1 evaluation results of the catalysts of example 1 and comparative example 1

As shown in Table 1, the catalyst of example 1 exhibited a large difference from the catalyst of comparative example 1 in the initial stage of the reaction because the gas phase reaction was a diffusion-limited reaction, and in the catalyst of example 1, the synthesis of the organic cage was carried out on the outer surface of the catalyst, whereas in the catalyst of comparative example 1, the synthesis of the organic cage was carried out at all positions of the catalyst. The "diffusion limitation" means a limiting step affecting the overall reaction rate, and is a step in which the reaction molecules diffuse from the catalyst surface to the active sites of the catalyst. Because the reaction is fast and the diffusion is slow, part of acetylene molecules are not desorbed after ethylene is generated through hydrogenation reaction, ethane is generated through hydrogenation reaction of ethylene, the matched hydrogen is consumed on the surface of the catalyst, so that sufficient hydrogen does not exist in the catalyst, acetylene does not react and flows out of the reactor, and therefore, the acetylene residue at the outlet of the reactor in comparative example 1 is large. The catalysts of example 1 and comparative example 1 had little carbon four formation and little coking of the catalyst at 1500 hours of reaction, so that the catalysts of example 1 and comparative example 1 had little change in acetylene content at the reactor outlet at the initial stage of reaction and after 1500 hours.

Example 2

And (3) a carrier: a commercially available spherical alumina carrier was used, 3mm in diameter. After baking for 4 hours at 1150 ℃, the water absorption pore volume is 0.65m ³ Per gram, specific surface area of 15.07m ² And/g. 100g of the carrier was weighed.

And (3) preparing a catalyst:

(1) Weighing 66.56g of lactic acid, mixing with 100g of roasted carrier, and keeping the temperature at 200 ℃ for 1 hour to obtain a semi-finished catalyst D;

(2) Mixing 4.16mg of tri (4-formylphenyl) amine with 0.0017mg of trifluoroacetic acid, dissolving in 50ml of dichloroethane, then mixing with the catalyst D, stirring and dropwise adding a mixed solution of 4.65mg of p-phenylenediamine and 10ml of dichloroethane, standing the mixture at room temperature for 100 hours, pouring out residual liquid, washing with ethanol and deionized water respectively, and drying to obtain a semi-finished catalyst E;

(3) 0.057g of palladium acetylacetonate is dissolved in 50ml of chloroform and the palladium acetylacetonate is completely dissolved for later use.

(4) Immersing the semi-finished catalyst E in 50ml of ethanol solution, and dripping the solution prepared in the step (3) into a mixture of the semi-finished catalyst E and ethanol while stirring for 10 hours. Then, 10ml of formaldehyde solution was added dropwise to the above solution, stirred at 60℃for 1 hour, the solution was decanted, washed with deionized water, dried at 120℃and calcined at 300℃for 2 hours to obtain a semi-finished catalyst F.

(5) Weighing 0.02355g of silver nitrate, dissolving into 65g of deionized water, immersing a semi-finished catalyst F into the prepared solution, standing for 4 hours after the solution is fully absorbed, then dripping 10ml of formaldehyde solution into the solution (mixture), stirring for 1 hour at 60 ℃, pouring out the solution, washing with deionized water, and drying at 120 ℃ to obtain the required catalyst.

The catalyst prepared was measured by atomic absorption spectrometry to obtain the catalyst of example 2, wherein the mass content of Pd was 0.02% and the mass content of Ag was 0.015%.

Comparative example 2

And (3) a carrier: the same carrier as in example 2 was used, and the preparation conditions were the same, except that the constant temperature in step (1) was 260 ℃.

And (3) preparing a catalyst:

(1) Weighing 66.56g of lactic acid, mixing with 100g of roasted carrier, and adding the mixture into the mixture to keep the temperature at 260 ℃ for 1 hour to obtain a semi-finished catalyst D1;

(2) Mixing 4.16mg of tri (4-formylphenyl) amine with 0.0017mg of trifluoroacetic acid, dissolving in 50ml of dichloroethane, then mixing with the catalyst D, stirring, dropwise adding a mixed solution of 4.65mg of p-phenylenediamine and 10ml of dichloroethane, standing the mixture at room temperature for 100 hours, pouring out residual liquid, washing with ethanol and deionized water respectively, and drying to obtain a semi-finished catalyst E1;

(4) The semi-finished catalyst E1 was immersed in 50ml of an ethanol solution, and the solution prepared in step (3) was added dropwise to a mixture of the support and ethanol while stirring for 10 hours. Then, 10ml of formaldehyde solution was added dropwise to the above solution, stirred at 60℃for 1 hour, the solution was decanted, washed with deionized water, dried at 120℃and calcined at 300℃for 2 hours to obtain a semi-finished catalyst F1.

(5) Weighing 0.02355g of silver nitrate, dissolving the silver nitrate into 68g of deionized water, immersing a semi-finished catalyst F1 into the prepared solution, standing for 4 hours after the solution is fully absorbed, then dripping 10ml of formaldehyde solution into the solution (mixture), stirring for 1 hour at 60 ℃, pouring out the solution, washing with deionized water, and drying at 120 ℃ to obtain the required catalyst.

The catalyst prepared by atomic absorption spectrometry was found to give a catalyst of comparative example 2 having a Pd mass content of 0.04% and an Ag mass content of 0.015%.

Effect of the invention

Working condition 1

The process conditions are as follows: the space velocity of the material is 4000/h, the operating pressure is 2.0MPa, the inlet temperature of the reactor is 55 ℃, and the catalyst loading amount is 200mL.

The hydrogenated materials are composed of:

Acetylene 0.3% (v/v), ethylene 80% (v/v), carbon three 0.5% (v/v), hydrogen/alkyne 1.8.

Table 2 evaluation results of example 2 and comparative example 2 catalysts under working condition 1

In the preparation process of the catalyst of comparative example 2, the polymerization is carried out at the temperature of 260 ℃ after the lactic acid is added, at which the lactic acid cannot be polymerized, most of the lactic acid overflows the carrier, and after the tri (4-formylphenyl) amine and the biphenyldiamine are added, the synthesis of the organic cage is carried out at all positions of the carrier, and palladium is also loaded at all positions of the carrier, so that the catalyst with almost uniformly distributed palladium active centers is formed. The hydrogenation reaction conditions were very similar to those of comparative example 1. That is, the reactor outlet acetylene content of comparative example 2 was high at the initial stage of the reaction, and the catalyst performance change after 1500 hours was small.

Working condition 2:

The hydrogenated materials are composed of:

acetylene 0.3% (v/v), ethylene 80% (v/v), carbon three 0.5% (v/v), hydrogen/alkyne 2.0.

Table 3 evaluation results of example 2 and comparative example 2 catalysts under operating condition 2

Compared with the working condition 1, the working condition 2 has the advantages that the molar ratio of hydrogen to acetylene is improved, the acetylene content at the outlet of the reactor in the comparative example 2 is greatly reduced, but the reactor is still unqualified, and the limitation of the diffusion process indicates that for gas phase hydrogenation, acetylene molecules cannot reach the inside of the catalyst quickly, and even if excessive hydrogen is added, only excessive ethylene hydrogenation can occur, so that acetylene cannot be completely removed.

Example 3

And (3) a carrier: the titanium oxide mass content is 20% and the diameter is 4mm by using the commercial spherical alumina-titanium oxide carrier. After roasting for 4 hours at 1100 ℃, the pore volume is 0.47m ³ Per gram, specific surface area of 30.64m ² And/g. 100g of the carrier was weighed.

And (3) preparing a catalyst:

(1) Weighing 10.5g of acrylic acid, 27.2g of water, 0.01g of potassium hypophosphite monohydrate, 0.023g of copper acetate monohydrate, 0.16ml of 30wt% hydrogen peroxide as an initiator, uniformly mixing, adding 100g of calcined carrier, transferring to a reflux bottle after the solution is completely absorbed, heating to 80 ℃ under stirring, and keeping the temperature for 1 hour to obtain a semi-finished catalyst H;

(2) 7.5mg of tris (4-formylphenyl) amine and 0.0025mg of trichloroacetic acid are taken and mixed, dissolved in 50ml of dichloroethane, then mixed with catalyst H, stirred and dropwise added with a mixed solution of 9.14mg of 2-chloro-p-phenylenediamine and 10ml of trichloroethane, the mixture is kept stand at room temperature for 150 hours, residual liquid is poured out, and the residual liquid is respectively washed with ethanol and deionized water and dried to obtain a catalyst J;

(3) 0.086g of palladium acetylacetonate is dissolved in 50ml of chloroform, and the palladium acetate is completely dissolved for standby.

(4) Catalyst J was immersed in 50ml of methanol solution, and the solution prepared in step (3) was added dropwise to a mixture of the support and ethanol while stirring for 15 hours. Then, 10ml of formic acid solution was added dropwise to the above solution, heated and stirred at 70℃for 2 hours, the solution was decanted, washed with deionized water, dried at 120℃and calcined at 400℃for 2 hours to obtain catalyst K.

(5) Silver nitrate 0.027g is dissolved in 45g deionized water, a catalyst K is immersed in the prepared solution, after the solution is fully absorbed, the solution is stood for 4 hours, 5ml of 10wt% hydrazine hydrate solution is added, the solution (mixture) is dropwise added, stirring is carried out for 1 hour at room temperature, the solution is poured off, washing is carried out by deionized water, and drying is carried out at 120 ℃ to obtain the required catalyst.

The catalyst prepared by atomic absorption spectrometry gave a catalyst of example 3 having a Pd mass content of 0.03% and an Ag mass content of 0.017%.

Comparative example 3

And (3) preparing a catalyst: the active components are the same in content, and the catalyst is prepared by adopting a traditional method. The same carrier as in example 3 was used.

(1) Weighing 0.5g of palladium chloride, dissolving in hydrochloric acid, diluting the solution to 47g, regulating the pH to 2.5, mixing with 100g of the roasted carrier, stirring until the solution is completely absorbed, drying 120, and roasting 550 to obtain a semi-finished catalyst H1;

(2) Silver nitrate 0.027g is dissolved in deionized water of 47g, catalytic H1 is immersed in the prepared solution, after the solution is fully absorbed, the solution is stood for 4 hours, dried at 120 and roasted at 550 ℃ to obtain the required catalyst.

The catalyst prepared by atomic absorption spectrometry was found to give a catalyst of comparative example 3 having a Pd mass content of 0.03% and an Ag mass content of 0.017%.

The implementation effect is as follows:

working condition 1

The process conditions are as follows: in the two-stage hydrogenation process, the space velocity of materials is 2500/h, the operating pressure is 3.0MPa, the inlet temperature of the first-stage reactor is 45 ℃, the inlet temperature of the second-stage reactor is 65 ℃, and the catalyst loading of each reactor is 100mL.

The hydrogenated materials are composed of:

acetylene 0.5% (v/v), ethylene 70% (v/v), carbon three 0.8% (v/v), one-stage hydrogen/alkyne 1.1, two-stage hydrogen/alkyne 1.8

Table 4 evaluation results of example 3 and comparative example 3 catalysts under working condition 1

Catalyst regeneration:

the catalysts of example 3 and comparative example 3 were steam extracted at 380℃for 20 hours, warmed to 400℃and then burned with 1% -5% by volume of air containing steam for 30 hours and hydrogen reduced at 130℃for 4 hours.

The regenerated catalyst of example 3 and comparative example 3 was evaluated under the above-mentioned condition 1, and the 24-hour reaction conditions are shown in Table 5.

Table 5 evaluation results of regenerated catalyst of example 3 and comparative example 3 under working condition 1

As shown in Table 5, under the same working condition 1, the catalyst of the invention has obviously higher acetylene conversion rate in the first-stage reaction than that of comparative example 3, and the coking amount of the catalyst is also obviously lower than that of comparative example 3. It is thus shown that the performance of the example catalyst remains very good after regeneration at lower temperatures (not exceeding 450 ℃).

Working condition 2

The process conditions are as follows: in the two-stage hydrogenation process, the space velocity of materials is 2500/h, the operating pressure is 3.0MPa, the inlet temperature of the first-stage reactor is 45 ℃, the inlet temperature of the second-stage reactor is 55 ℃, and the catalyst loading of each reactor is 100mL.

The hydrogenated materials are composed of:

acetylene 0.5% (v/v), ethylene 70% (v/v), carbon three 0.8% (v/v), one-stage hydrogen/alkyne 1.3, two-stage hydrogen/alkyne 1.5

Table 6 evaluation results of example 3 and comparative example 3 catalysts under working condition 2

As shown in Table 6, under the working condition 2, the molar ratio of hydrogen to alkyne is 1.3, the catalyst of the example 3 can realize complete conversion of acetylene before the catalytic reaction is carried out for 500 hours, which indicates that the catalyst of the example 3 has good selectivity and stability, and the conversion rate of acetylene is reduced more rapidly when the catalyst prepared by the conventional method of the comparative example 3 is used for hydrogenation of acetylene.

As shown by the amount of carbon four produced in Table 6 for 500 hours, the catalyst of the present invention was more stable in that the amount of carbon four produced when used in the catalytic reaction was only 1/3 of that of comparative example 3.

Example 4

And (3) a carrier: adopts commercial tooth-ball type alumina-magnesia carrier, the magnesia mass content is 5Percent, diameter is 3mm. Roasting at 1130 deg.c for 4 hr to obtain pore volume of 0.52m ³ Per gram, specific surface area of 25.67m ² And/g. 100g of the carrier was weighed.

And (3) preparing a catalyst:

(1) Weighing 56.58g of lactic acid, mixing with 100g of roasted carrier, and keeping the temperature at 190 ℃ for 2 hours to obtain a semi-finished catalyst M;

(2) Mixing 16.5mg of tri (4-formylphenyl) amine with 0.0028mg of trifluoroacetic acid, dissolving in 50ml of dichloroethane, then mixing with a semi-finished catalyst M, stirring, dropwise adding a mixed solution of 11.06mg of p-phenylenediamine and 10ml of dichloroethane, standing the mixture at room temperature for 180 hours, pouring out residual liquid, washing with ethanol and deionized water respectively, and drying to obtain a semi-finished catalyst N;

(3) 0.070g of palladium acetate is dissolved in 50ml of chloroform, and the palladium acetate is completely dissolved for standby.

(4) Immersing the semi-finished catalyst N in 50ml of ethanol solution, and dripping the solution prepared in the step (3) into a mixture of the carrier and the ethanol while stirring for 8 hours. Then, 20ml of methanol solution was added dropwise to the above solution, stirred at 80℃for 1 hour, the solution was decanted, washed with deionized water, dried at 120℃and calcined at 400℃for 1 hour to obtain a semi-finished catalyst P.

(5) Dissolving 0.0318g of silver nitrate into 50g of deionized water, immersing a semi-finished catalyst P into the prepared solution, standing for 4 hours after the solution is fully absorbed, dripping 20ml of formic acid solution into the solution, stirring for 1 hour at 80 ℃, pouring out the solution, washing with deionized water, and drying at 120 ℃ to obtain the required catalyst.

The catalyst prepared by atomic absorption spectrometry gave a catalyst of example 4 having a Pd mass content of 0.033% and an Ag mass content of 0.020%.

Comparative example 4

The catalyst support and preparation conditions were the same as in example 4, except that the molar number of biphenyldiamine was 1/2 of that of tris (4-formylphenyl) amine.

And (3) a carrier: the commercial tooth-ball type alumina-magnesia carrier is adopted, the mass content of magnesia is 5 percent, and the diameter is 3mm.Roasting at 1130 deg.c for 4 hr to obtain pore volume of 0.52m ³ Per gram, specific surface area of 25.67m ² And/g. 100g of the carrier was weighed.

And (3) preparing a catalyst:

(2) Mixing 16.5mg of tri (4-formylphenyl) amine with 0.0028mg of trifluoroacetic acid, dissolving in 50ml of dichloroethane, then mixing with a semi-finished catalyst M, stirring, dropwise adding a mixed solution of 4.6mg of p-phenylenediamine and 10ml of dichloroethane, standing the mixture at room temperature for 180 hours, pouring out residual liquid, washing with ethanol and deionized water respectively, and drying to obtain a semi-finished catalyst N;

Effect of the invention

Working condition 1

The process conditions are as follows: the second-stage hydrogenation process has material space velocity of 6000/h and operation pressure of 2.6MPa, the inlet temperature of the first-stage reactor is 55 ℃, the inlet temperature of the second-stage reactor is 70 ℃, and the catalyst loading of each reactor is 100mL.

The hydrogenated materials are composed of:

acetylene 1.0% (v/v), ethylene 90% (v/v), carbon three 0.4% (v/v), one-stage hydrogen/alkyne 1.2, two-stage hydrogen/alkyne 1.6

Table 7 evaluation results of example 4 and comparative example 4 catalyst under working condition 1

As shown in Table 7, the outlets of the first-stage reactors of example 4 and comparative example 4 were greatly different at 24 hours, 500 hours and 1000 hours of the reaction; the two-stage reactor outlet of comparative example 4 was also unacceptable, probably because the amount of tris (4-formylphenyl) amine was much higher than that of biphenyldiamine in the catalyst synthesis of comparative example 4, resulting in a large number of synthetic organic cages, most of which did not form complete organic cages, and the number of active sites formed after Pd loading was excessive, but the size of active sites was small, and there was no significant activity under the present operating conditions, rendering part of the acetylene unconverted.

Working condition 2

The process conditions are as follows: the second-stage hydrogenation process has material space velocity of 6000/h and operation pressure of 2.6MPa, the inlet temperature of the first-stage reactor is 50 ℃, the inlet temperature of the second-stage reactor is 80 ℃, and the catalyst loading of each reactor is 100mL.

The hydrogenated materials are composed of:

acetylene 1.2% (v/v), ethylene 90% (v/v), carbon three 0.4% (v/v), one-stage hydrogen/alkyne 1.3, two-stage hydrogen/alkyne 2.0

Table 8 evaluation results of example 4 and comparative example 4 catalyst under operating condition 2

As shown in Table 8, while the selectivity of the one-stage reaction of comparative example 4 was slightly higher than that of example 4, comparative example 4 was far different in acetylene conversion and the green oil production was far higher than that of example 4. The reason for this may be that the active center is small in size and the activation ability to hydrogen is insufficient, resulting in that the vinyl group formed cannot react with hydrogen in time, and finally more butadiene is formed.

Example 5

And (3) a carrier: the spherical alumina-magnesia carrier is adopted, the magnesia mass content is 10 percent, and the diameter is 2mm. After being roasted for 4 hours at 1080 ℃, the pore volume is 0.50m ³ Per gram, specific surface area of 35.36m ² And/g. 100g of the carrier was weighed.

And (3) preparing a catalyst:

(1) Weighing 60.8g of lactic acid, mixing with 100g of roasted carrier, and keeping the temperature at 190 ℃ for 2 hours to obtain a semi-finished catalyst Q;

(2) Mixing 66.67mg of tri (4-formylphenyl) amine with 0.0167mg of dichloroacetic acid, dissolving in 50ml of dichloroethane, then mixing with a catalyst Q, stirring and dropwise adding a mixed solution of 55.87mg of p-phenylenediamine and 10ml of dichloroethane, standing the mixture at room temperature for 190 hours, pouring out residual liquid, washing with ethanol and deionized water respectively, and drying to obtain a semi-finished catalyst R;

(3) 0.1g of palladium acetylacetonate is dissolved in 50ml of benzene and the palladium acetate is completely dissolved for later use.

(4) The semi-finished catalyst R was immersed in 50ml of a methanol solution, and the solution prepared in step (3) was added dropwise to a mixture of the support and methanol while stirring for 20 hours. Then, 10ml of formaldehyde solution was added dropwise to the above solution, stirred at 50℃for 1 hour, the solution was decanted, washed with deionized water, dried at 120℃and calcined at 380℃for 1 hour to obtain a semi-finished catalyst S.

(5) Silver nitrate 0.0397g is dissolved in 50g of ionized water, a semi-finished catalyst S is immersed in the prepared solution, after the solution is fully absorbed, the solution is kept stand for 4 hours, 20ml of formic acid solution is added into the solution dropwise, the solution is stirred for 1 hour at 50 ℃, the solution is poured off, washed by deionized water and dried at 120 ℃ to obtain the required catalyst.

The catalyst prepared was measured by atomic absorption spectrometry to obtain the catalyst of example 5, wherein the mass content of Pd was 0.035% and the mass content of Ag was 0.025%.

Comparative example 5

In comparative example 5, the baking temperature in step (4) was lower than the decomposition temperature of polylactic acid.

And (3) preparing a catalyst:

(1) Weighing 60.8g of lactic acid, mixing with 100g of roasted carrier, and adding the mixture to keep the temperature at 190 ℃ for 2 hours to obtain a semi-finished catalyst Q1;

(2) Mixing 66.67mg of tri (4-formylphenyl) amine with 0.0167mg of dichloroacetic acid, dissolving in 50ml of dichloroethane, then mixing with a catalyst Q1, stirring, dropwise adding a mixed solution of 55.87mg of p-phenylenediamine and 10ml of dichloroethane, standing the mixture at room temperature for 190 hours, pouring out residual liquid, washing with ethanol and deionized water respectively, and drying to obtain a semi-finished catalyst R1;

(4) The semi-finished catalyst R1 was immersed in 50ml of a methanol solution, and the solution prepared in step (3) was added dropwise to a mixture of the support and methanol while stirring for 20 hours. Then, 10ml of formaldehyde solution was added dropwise to the above solution, stirred at 50℃for 1 hour, the solution was decanted, washed with deionized water, dried at 120℃and calcined at 230℃for 1 hour to obtain a semi-finished catalyst S1.

(5) Silver nitrate 0.0397g is dissolved in 50g of ionized water, a semi-finished catalyst S1 is immersed in the prepared solution, after the solution is fully absorbed, the solution is kept stand for 4 hours, 20ml of formic acid solution is added into the solution dropwise, the solution is stirred for 1 hour at 50 ℃, the solution is poured off, washed by deionized water and dried at 120 ℃ to obtain the required catalyst.

The catalyst prepared by atomic absorption spectrometry gave a catalyst of comparative example 5 having a Pd mass content of 0.035% and an Ag mass content of 0.025%.

Effect of the invention

The process conditions are as follows: three-stage hydrogenation process, material space velocity 4000/h, operating pressure 2.6MPa, inlet temperature of one-stage reactor 45 ℃ and hydrogen/alkyne 0.9; the inlet temperature of the second-stage reactor is 55 ℃, and the hydrogen/alkyne is 1.2; the inlet temperature of the three-stage reactor is 80 ℃ and the hydrogen/alkyne is 2.0. The catalyst loading of each reactor was 100mL.

The hydrogenated materials are composed of:

acetylene 1.4% (v/v), ethylene 85% (v/v), and carbon three 0.2% (v/v).

Table 9 evaluation results of the catalyst of example 5 and comparative example 5

As shown in Table 9, at a hydrogen/alkyne of 1.2, the conversion of acetylene in the second stage of comparative example 5 was 0.15% in 1000 hours; in the case where the molar ratio of hydrogen/alkyne reaches 2, the three-stage acetylene conversion of comparative example 5 is only 0.016% for 1000 hours, because the calcination temperature in step (4) is lower than the decomposition temperature of polylactic acid, so that the internal pores of the catalyst remain occupied by the polymer, the reaction molecules cannot pass through the catalyst, and only a very small portion of the active center at the outermost surface of the catalyst can undergo hydrogenation reaction.

Example 6

And (3) a carrier: the mass content of alumina is 97%, the mass content of titanium oxide is 3% and the diameter is 3mm by adopting a commercially available spherical carrier. Roasting for 4 hours at 1070 ℃ and then obtaining the pore volume of 0.55m ³ Per gram, specific surface area of 35.07m ² And/g. 100g of the carrier was weighed.

And (3) preparing a catalyst:

(1) Weighing 63.00g of lactic acid, mixing with 100g of roasted carrier, and keeping the temperature at 190 ℃ for 1 hour to obtain a semi-finished catalyst U;

(2) Mixing 89.10mg of tris (4-formylphenyl) amine with 0.018mg of trifluoroacetic acid, dissolving in 50ml of dichloroethane, then mixing with a semi-finished catalyst U, stirring and dropwise adding a mixed solution of 74.67mg of p-phenylenediamine and 10ml of chloroethane, standing the mixture at room temperature for 100 hours, pouring out residual liquid, washing with ethanol and deionized water respectively, and drying to obtain a semi-finished catalyst V;

(3) 80.19mg of palladium acetate was dissolved in 50ml of dichloroethane, and the solution was prepared until the palladium acetate was completely dissolved.

(4) Immersing the semi-finished catalyst V in 50ml of ethanol solution, and dripping the solution prepared in the step (3) into a mixture of the carrier and the ethanol while stirring for 18 hours. Then, 30ml of an acetaldehyde solution was added dropwise to the above solution, stirred at 60℃for 1 hour, the solution was decanted, washed with deionized water, dried at 120℃and calcined at 370℃for 2 hours to obtain a catalyst W.

(5) Weighing 0.0236g of silver nitrate, dissolving into 54.46g of deionized water, immersing the catalyst W into the prepared solution, standing for 4 hours after the solution is fully absorbed, dripping 50ml of acetaldehyde solution into the solution, stirring for 1 hour at 80 ℃, pouring out the solution, washing with deionized water, and drying at 120 ℃ to obtain the required catalyst.

The catalyst prepared was measured by atomic absorption spectrometry to obtain the catalyst of example 6, wherein the mass content of Pd was 0.038% and the mass content of Ag was 0.015%.

Comparative example 6

And (3) a carrier: the catalyst was prepared using the same support as in example 6, using tris (4-formylphenyl) amine and p-phenylenediamine.

And (3) preparing a catalyst:

(1) Weighing 63 g of lactic acid, mixing with 100g of roasted carrier, and keeping the temperature at 190 ℃ for 1 hour to obtain a semi-finished catalyst U1;

(2) Mixing 89.10mg of tris (4-formylphenyl) amine with 0.018mg of trifluoroacetic acid, dissolving in 50ml of dichloroethane, then mixing with a semi-finished catalyst U1, stirring, dropwise adding a mixed solution of 43.8mg of p-phenylenediamine and 10ml of chloroethane, standing the mixture at room temperature for 100 hours, pouring out residual liquid, washing with ethanol and deionized water respectively, and drying to obtain a semi-finished catalyst V1;

(4) The semi-finished catalyst V1 was immersed in 50ml of an ethanol solution, and the solution prepared in step (3) was added dropwise to a mixture of the support and ethanol while stirring for 18 hours. Then, 30ml of an acetaldehyde solution was added dropwise to the above solution, stirred at 60℃for 1 hour, the solution was decanted, washed with deionized water, dried at 120℃and calcined at 370℃for 2 hours to obtain a catalyst W1.

(5) Weighing 0.0236g of silver nitrate, dissolving into 54.46g of deionized water, immersing the catalyst W1 into the prepared solution, standing for 4 hours after the solution is completely absorbed, dripping 50ml of acetaldehyde solution into the solution, stirring for 1 hour at 80 ℃, pouring out the solution, washing with deionized water, and drying at 120 ℃ to obtain the required catalyst.

The catalyst prepared by atomic absorption spectrometry was found to give a catalyst of comparative example 6 having a Pd mass content of 0.038% and an Ag mass content of 0.015%.

Effect of the invention

The process conditions are as follows: three-stage hydrogenation process, material airspeed 4000/h, operating pressure 2.3MPa, inlet temperature of one-stage reactor 50 ℃ and hydrogen/alkyne 1.3; the inlet temperature of the second-stage reactor is 60 ℃ and the hydrogen/alkyne is 1.5; the inlet temperature of the three-stage reactor is 75 ℃ and the hydrogen/alkyne is 1.8. The catalyst loading of each reactor was 100mL.

The hydrogenated materials are composed of:

acetylene 2.0% (v/v), ethylene 80% (v/v), and carbon three 0.3% (v/v).

Table 10 evaluation results of the catalysts of example 6 and comparative example 6

As shown in Table 10, even though the 3-stage reactors were connected in series, the acetylene residue at the outlet of the third-stage reactor in comparative example 6 was still large, indicating that the catalyst activity of comparative example 6 was severely insufficient. The reason is probably that when phenylenediamine is used as a polymerization monomer, the volume of the organic cage obtained by synthesis is too small, and the active center obtained after Pd loading is too small, which is lower than the minimum volume required for the minimum activity, resulting in that a considerable portion of active centers are not sufficiently active under the evaluation conditions of this example.

Example 7

And (3) a carrier: a commercially available spherical alumina carrier was used, 3mm in diameter. After baking for 4 hours at 1150 ℃, the water absorption pore volume is 0.45m ³ Per gram, specific surface area of 15.17m ² And/g. 100g of the carrier was weighed.

And (3) preparing a catalyst:

(1) Mixing 53.00g of lactic acid with 100g of roasted carrier, and keeping the temperature at 210 ℃ for 2 hours to obtain a semi-finished catalyst X;

(2) Mixing 63.49mg of tris (4-formylphenyl) amine with 0.0115mg of trifluoroacetic acid, dissolving in 50ml of dichloroethane, then mixing with a semi-finished catalyst X, stirring and dropwise adding a mixed solution of 77.64mg of 2.5-dimethylbiphenyl diamine and 10ml of dichloroethane, standing the mixture at room temperature for 120 hours, pouring out residual liquid, washing with ethanol and deionized water respectively, and drying to obtain a semi-finished catalyst Y;

(3) 0.115g of palladium acetylacetonate is weighed and dissolved in 50ml of dichloroethane, and the palladium acetate is completely dissolved for standby.

(4) Immersing the semi-finished catalyst Y in 50ml of ethanol solution, and dripping the solution prepared in the step (3) into a mixture of the carrier and methanol while stirring for 15 hours. Then 3ml of 5% hydrazine hydrate solution was added dropwise to the above solution, stirred at room temperature for 1 hour, poured off the solution, washed with deionized water, dried at 120℃and calcined at 300℃for 2 hours to obtain a semi-finished catalyst Z.

(5) Weighing 0.0285g of silver nitrate, dissolving into 45g of deionized water, immersing a semi-finished catalyst Z into the prepared solution, standing for 4 hours after the solution is completely absorbed, dripping 3ml of 5% hydrazine hydrate solution into the solution, stirring for 1 hour at room temperature, pouring out the solution, washing with deionized water, drying at 120 ℃, and roasting at 500 ℃ for 4 hours to obtain the required catalyst.

The catalyst prepared was measured by atomic absorption spectrometry to obtain the catalyst of example 7, wherein the mass content of Pd was 0.04% and the mass content of Ag was 0.018%.

Comparative example 7

And (3) a carrier: the same carrier as in example 7 was used, and the preparation conditions were the same except that silver was not supported.

And (3) preparing a catalyst:

(1) Mixing 53.00g of lactic acid with 100g of roasted carrier, and keeping the temperature at 210 ℃ for 2 hours to obtain a semi-finished catalyst X1;

(2) Mixing 63.49mg of tris (4-formylphenyl) amine with 0.0115mg of trifluoroacetic acid, dissolving in 50ml of dichloroethane, then mixing with a semi-finished catalyst X, stirring and dropwise adding a mixed solution of 77.64mg of 2.5-dimethylbiphenyl diamine and 10ml of dichloroethane, standing the mixture at room temperature for 120 hours, pouring out residual liquid, washing with ethanol and deionized water respectively, and drying to obtain a semi-finished catalyst Y1;

(4) Immersing the semi-finished catalyst Y in 50ml of ethanol solution, and dripping the solution prepared in the step (3) into a mixture of the carrier and methanol while stirring for 15 hours. Then 3ml of 5% hydrazine hydrate solution was added dropwise to the above solution, stirred at room temperature for 1 hour, poured off the solution, washed with deionized water, dried at 120℃and calcined at 300℃for 2 hours to obtain a semi-finished catalyst Z1.

(5) Immersing the semi-finished catalyst Z into the prepared solution, standing for 4 hours after the solution is fully absorbed, dropwise adding 3ml of 5% hydrazine hydrate solution into the solution, stirring for 1 hour at room temperature, pouring out the solution, washing with deionized water, drying at 120 ℃, and roasting at 500 ℃ for 4 hours to obtain the required catalyst.

The catalyst prepared by atomic absorption spectrometry was found to give a catalyst of comparative example 7 having a Pd mass content of 0.03%.

Effect of the invention

The process conditions are as follows: three-stage hydrogenation process, material space velocity of 3000/h, operating pressure of 2.3MPa, inlet temperature of 42 ℃ of a first-stage reactor and hydrogen/alkyne of 1.0; the inlet temperature of the second-stage reactor is 56 ℃, and the hydrogen/alkyne is 1.4; the inlet temperature of the three-stage reactor is 80 ℃ and the hydrogen/alkyne is 1.5. The catalyst loading of each reactor was 100mL.

And (3) reduction of a catalyst: pure hydrogen, a space velocity of reduction of 100/h and a reduction time of 5 hours at 150 ℃.

The hydrogenated materials are composed of:

acetylene 2.0% (v/v), ethylene 80% (v/v), and carbon three 0.3% (v/v).

Table 11 evaluation results of the catalysts of example 7 and comparative example 7

As shown in Table 11, at 24 hours of reaction, comparative example 7 was comparable to the first stage reactor outlet acetylene content of example 7, and the second stage reactor outlet acetylene content was significantly different; after 1000 hours of reaction, the three-stage reactor outlet acetylene content of comparative example 7 was already unacceptable. The reason is that when trace acetylene exists, the active site occupied by acetylene is limited, and the hydrogenation of ethylene cannot be limited, so that excessive ethylene is hydrogenated to consume hydrogen, so that trace acetylene overflows the reactor, and the product is disqualified. After silver and palladium in the catalyst form an alloy, outer electrons of the silver enter an outer empty track of the palladium, so that the fraction of empty tracks is reduced, electrons of ethylene enter the empty track of the palladium less, the adsorption strength of ethylene on the surface of the catalyst is reduced, the probability of hydrogenation reaction is reduced, and the selectivity of catalytic reaction is improved.

Of course, the present invention is capable of other various embodiments and its several details are capable of modification and variation in light of the present invention by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. The alkyne selective hydrogenation method is characterized in that in the alkyne selective hydrogenation method, the inlet temperature of a hydrogenation reactor is 45-80 ℃, the pressure is 1.5-3.0 MPa, and the gas volume space velocity is 2000-6000 h ^-1 The method comprises the steps of carrying out a first treatment on the surface of the The catalyst used in the alkyne selective hydrogenation reaction: the carrier is alumina or alumina mainly, the specific surface area of the catalyst15-40 m ² /g; the active components are Pd and Ag, the mass content of Pd is 0.02-0.04% and the mass content of Ag is 0.03-0.015% calculated by taking the mass of the carrier as 100%, the active component palladium is loaded in an organic cage, the organic cage is positioned on the outer surface of the catalyst, and the size of the organic cage is 1.4-2.6 nm.

2. The alkyne selective hydrogenation process according to claim 1, wherein the hydrogenation reactor is an adiabatic reactor or an isothermal reactor; the hydrogenation reactor is a one-stage reactor or a two-stage reactor.

3. The alkyne selective hydrogenation process according to claim 2, wherein the reactor is a fixed bed one-stage reactor, the reactor inlet hydrogen/alkyne molar ratio is 1.3-2.0, and the reactor inlet acetylene volume content is 0.1-0.8%; or the reactor is a fixed bed two-stage reactor, the mole ratio of hydrogen to alkyne at the inlet of the first-stage reactor is 1.1-1.3, the mole ratio of hydrogen to alkyne at the inlet of the second-stage reactor is 1.4-2.0, and the volume content of acetylene at the inlet of the first-stage reactor is 0.7-1.5%; or the reactor is a fixed bed three-stage reactor, the mole ratio of hydrogen/alkyne at the inlet of the first-stage reactor is 0.9-1.3, the mole ratio of hydrogen/alkyne at the inlet of the second-stage reactor is 1.1-1.5, the mole ratio of hydrogen/alkyne at the inlet of the three-stage reactor is 1.5-2.0, and the volume content of acetylene at the inlet of the first-stage reactor is 1.0-2.0%.

4. The alkyne selective hydrogenation process according to claim 1, wherein the hydrogenation material is a carbon two fraction, the carbon two fraction enters a hydrogenation reactor for gas phase hydrogenation to remove acetylene, the ethylene volume content in the carbon two fraction is 60-90%, and the acetylene volume content is 0.1-1.0%.

5. The alkyne selective hydrogenation process according to claim 1, wherein the process for preparing the catalyst comprises:

(4) Immersing the semi-finished catalyst B in an alcohol solution, dripping the palladium precursor solution prepared in the step (3) into a mixture of the semi-finished catalyst B and alcohol, stirring, dripping a reducing agent, heating and stirring until the surface of the semi-finished catalyst B is not discolored, pouring the solution, washing with deionized water, drying, and roasting at a temperature at which an organic polymer can be decomposed to obtain a semi-finished catalyst C;

(5) And (3) dissolving a silver-containing compound in deionized water or organic solution to obtain a silver impregnation solution, immersing the semi-finished catalyst C in the silver impregnation solution, standing after the semi-finished catalyst C is completely absorbed, dropwise adding a reducing agent to reduce silver, pouring the solution, washing with deionized water, and drying to obtain the catalyst, or not reducing, pouring the solution, washing with deionized water, drying and roasting to obtain the catalyst.

6. The alkyne selective hydrogenation process according to claim 5, wherein the volume of the hydrophilic polymerizable monomer polymerized in step 1 is 80-100%, preferably 85-95% of the pore volume of the carrier; in the step 2, the reaction of the tri (4-formylphenyl) amine and the aromatic diamine compound is carried out under the catalysis of halogenated acetic acid, and the molar ratio of the aromatic diamine compound to the tri (4-formylphenyl) amine is 1.2-2.0: 1, a step of; in step 3, the mass ratio of palladium contained in the organic palladium compound to tris (4-formylphenyl) amine is 0.63-4.8:1.

7. The alkyne selective hydrogenation process of claim 5, wherein the hydrophilic polymerizable monomer comprises a carbonyl group, a carboxyl group, or a carbon-carbon double bond; the hydrophilic polymerizable monomer may undergo polymerization or condensation reaction at less than 420 ℃; the hydrophilic polymerizable monomer can decompose at a temperature below 450 ℃ after polymerization.

8. The alkyne selective hydrogenation process according to claim 5, wherein said organopalladium compound is palladium acetate or palladium acetylacetonate; the silver-containing compound is a soluble silver salt; the reducing agent is methanol, formaldehyde, formic acid, ethanol, acetaldehyde or hydrazine hydrate.

9. The method for selective hydrogenation of alkyne according to claim 5, wherein said aromatic diamine compound is biphenyldiamine, terphenyldiamine, biphenyldiamine having substituent on benzene ring or terphenyldiamine having substituent on benzene ring; preferably biphenyldiamine or p-biphenyldiamine having a substituent on the benzene ring.

10. The alkyne selective hydrogenation process of claim 5, wherein the hydrophilic polymerizable monomer comprises a carbonyl group, a carboxyl group, or a carbon-carbon double bond; the hydrophilic polymerizable monomer may undergo polymerization or condensation reaction at less than 420 ℃; the hydrophilic polymerizable monomer can decompose at a temperature below 450 ℃ after polymerization.