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CN113333034B - Regeneration method and application of chloronitroaromatic hydrocarbon selective hydrogenation catalyst - Google Patents

Regeneration method and application of chloronitroaromatic hydrocarbon selective hydrogenation catalyst Download PDF

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CN113333034B
CN113333034B CN202110392296.6A CN202110392296A CN113333034B CN 113333034 B CN113333034 B CN 113333034B CN 202110392296 A CN202110392296 A CN 202110392296A CN 113333034 B CN113333034 B CN 113333034B
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chloronitroaromatic
selective hydrogenation
cat1
regeneration
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CN113333034A (en
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于文龙
丁军委
葛树文
徐广文
单玉领
刘福胜
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Qingdao University of Science and Technology
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J38/00—Regeneration or reactivation of catalysts, in general
    • B01J38/48—Liquid treating or treating in liquid phase, e.g. dissolved or suspended
    • B01J38/50—Liquid treating or treating in liquid phase, e.g. dissolved or suspended using organic liquids
    • B01J38/52—Liquid treating or treating in liquid phase, e.g. dissolved or suspended using organic liquids oxygen-containing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals
    • B01J23/42—Platinum
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals
    • B01J23/44—Palladium
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    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals
    • B01J23/46—Ruthenium, rhodium, osmium or iridium
    • B01J23/462—Ruthenium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J38/00—Regeneration or reactivation of catalysts, in general
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J38/00—Regeneration or reactivation of catalysts, in general
    • B01J38/02—Heat treatment
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    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C209/00—Preparation of compounds containing amino groups bound to a carbon skeleton
    • C07C209/30—Preparation of compounds containing amino groups bound to a carbon skeleton by reduction of nitrogen-to-oxygen or nitrogen-to-nitrogen bonds
    • C07C209/32—Preparation of compounds containing amino groups bound to a carbon skeleton by reduction of nitrogen-to-oxygen or nitrogen-to-nitrogen bonds by reduction of nitro groups
    • C07C209/36—Preparation of compounds containing amino groups bound to a carbon skeleton by reduction of nitrogen-to-oxygen or nitrogen-to-nitrogen bonds by reduction of nitro groups by reduction of nitro groups bound to carbon atoms of six-membered aromatic rings in presence of hydrogen-containing gases and a catalyst
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    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/50—Improvements relating to the production of bulk chemicals
    • Y02P20/584—Recycling of catalysts

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Abstract

The invention relates to the technical field of catalysts, and particularly discloses a regeneration method of a chloronitroaromatic selective hydrogenation catalyst. The regeneration method comprises the steps of immersing a part of deactivated catalyst in a titanium oxide precursor and a stabilizing solution, carbonizing, mixing the carbonized catalyst with the deactivated catalyst, adding the mixture into a regeneration kettle containing a treatment solution, and decomposing organic impurities under the action of ultraviolet irradiation and microwaves; the treated catalyst is subjected to microwave washing under the interaction of organic acid and organic solvent, so that dredging of pore channels and recovery of active metal sites are realized. The treatment method can effectively remove the organic impurities adsorbed in the catalyst and recover the catalytic performance. The method has the advantages of simplicity, high efficiency, environmental friendliness and the like, ensures the removal of organic impurities, can maintain the structure and the active metal loading state of the catalyst, effectively recovers the activity of the catalyst, and reduces the use cost of the catalyst.

Description

Regeneration method and application of chloronitroaromatic hydrocarbon selective hydrogenation catalyst
Field of the art
The invention relates to the technical field of catalysts, in particular to a regeneration method and application of a chloronitroaromatic selective hydrogenation catalyst.
(II) background art
Products produced by selective hydrogenation reaction of chloronitroaromatic hydrocarbon are widely applied to the production process of organic dyes, pesticides, synthetic fibers, plasticizers and printing and dyeing assistants. According to different reaction conditions, different products can be obtained after the chloronitroaromatic hydrocarbon is hydrogenated and reduced, and the products mainly comprise nitroso compounds, hydroxylamine, azobenzene and aromatic primary amine. The hydrogenation route is mainly divided into a direct route (nitroarene-nitrobenzene-hydroxylamine-aniline) and a condensation route (nitrobenzene-azoxybenzene-hydroazoxybenzene-aniline).
At present, the supported noble metal catalyst is mainly researched by the chloronitroaromatic selective hydrogenation catalyst. Noble metals (platinum, palladium, rhodium) have relatively strong adsorption properties due to the unfilled d electron orbitals in the outer layers of atoms, and can form covalent bonds with hydrogen atoms or oxygen atoms, and therefore exhibit relatively strong activity in redox reactions. Because the cost of the noble metal catalyst is relatively high, and the catalytic performance of the noble metal catalyst is gradually reduced along with the increase of the application times of the catalyst, the service life of the catalyst is shortened in the actual production process, which directly leads to the increase of the production cost of the product.
According to the previous extensive research results of the inventor, the main performance degradation of the carbon-supported noble metal catalyst in the selective hydrogenation reduction reaction of the chloronitroaromatic hydrocarbon is as follows: the organic impurities block the catalyst pore channels and cover the hydrogenation active sites, so that the hydrogenation activity is reduced. Extensive studies carried out earlier by the inventors have also found that washing with a single organic solvent has a very limited effect on restoring the specific surface area and pore volume of the deactivated catalyst. And non-mild regeneration methods such as strong acid cleaning can accelerate the damage of the catalyst carrier structure and the falling and loss of noble metal components, thereby further causing irreversible performance damage of the catalyst. Therefore, on the premise of not damaging the original structural property of the catalyst, the deactivated catalyst for selective hydrogenation of the chloronitroaromatic hydrocarbon is reasonably and effectively regenerated, so that the catalyst is recovered in catalytic activity, and the service life is prolonged, and is the key of the development of a novel process for selective hydrogenation production of the chloronitroaromatic hydrocarbon.
(III) summary of the invention
The invention provides a regeneration method and application of a chloronitroarene selective hydrogenation catalyst which has the characteristics of a tangential reaction, is mild and friendly to the original structural property of the catalyst and can greatly prolong the service life, and aims to make up the defects of the prior art.
The invention is realized by the following technical scheme:
A regeneration method of a chloronitroaromatic hydrocarbon selective hydrogenation catalyst takes a catalyst with reduced catalytic performance generated in the process of preparing chloroaromatic amine by selective hydrogenation by taking chloronitroaromatic hydrocarbon as a raw material as a treatment object, and comprises the following steps:
(1) Adding a part of deactivated catalyst into the mixed alcohol solution of the precursor A and the stabilizer B, heating, stirring and soaking, filtering the catalyst after soaking, transferring the catalyst into a tubular atmosphere furnace, heating and carbonizing in an inert atmosphere according to a programmed temperature, cooling the carbonized product, and preserving for later use;
(2) Adding the carbonized catalyst and the deactivated catalyst obtained in the step ⑴ into a regeneration kettle provided with an ultraviolet light generating device and a microwave generating device according to a certain dry basis mass ratio, adding a treatment liquid C, starting stirring under the ultraviolet light irradiation condition to perform regeneration treatment, and pressing the treated liquid into a precise filter by nitrogen to filter;
(3) The catalyst in the filter is backflushed into a regeneration kettle by adopting a solvent D, stirring is started under the auxiliary action of microwaves to wash, the washed feed liquid is pressed into a precise filter by nitrogen to be filtered, and filtrate is recovered for later use;
(4) And (3) back flushing the catalyst in the filter into a regeneration kettle by adopting deionized water, and filtering to obtain the regenerated wet-based catalyst.
The method comprises the steps of immersing a part of deactivated catalyst in a proper precursor and a stabilizing solution, carbonizing, anchoring organic amine impurities attached to the surface of the deactivated catalyst by the stabilizing solution to form stable structural nitrogen species in the carbonizing process, and catalyzing persulfate to decompose under the conditions of ultraviolet irradiation and microwaves by utilizing the catalytic action of the nitrogen species on the surface of the catalyst and the residual exposed metal active sites to generate high-activity free radicals; meanwhile, the precursor can generate nano titanium dioxide photoactive sites in situ in the carbonization process, and form a photocatalysis effect by being matched with ultraviolet light irradiation, so that the chain scission decomposition of organic macromolecular impurities on the surface of the deactivated catalyst is realized under mild conditions, and the carrier structure and the metal active sites of the catalyst are not damaged. And (3) carrying out microwave washing on the treated catalyst under the interaction of organic acid and organic solvent to remove organic micromolecular impurities formed by chain scission of organic macromolecular impurities and ammonia adsorbed on metal active sites. Thereby realizing the dredging of the pore canal of the deactivated catalyst and the recovery of the metal active site. The treatment method has mild conditions, and can effectively remove indissolvable macromolecular organic impurities blocked in the pore canal and covered on the metal active site under the condition of not damaging the pore canal structure of the catalyst and the noble metal load, and recover the catalytic performance.
The more preferable technical scheme of the invention is as follows:
The deactivated catalyst is one of Pt, pd and Ru loaded by activated carbon, nano porous carbon, porous carbon spheres, carbon nano tubes or activated carbon fibers.
In the step (1), the precursor A is one of n-propyl titanate, isopropyl titanate, n-butyl titanate and isobutyl titanate; the stabilizing solution B is one of terephthalaldehyde, isophthalaldehyde or o-phthalaldehyde; the solvent is one of methanol, ethanol or isopropanol; the content of the precursor A in the alcohol solution is 1% -30%, and the content of the stabilizer B in the solution is 5% -30%; the mass ratio of the dry-base deactivated catalyst to the alcohol solution is 1:4-20, and the impregnation temperature is 50-80 ℃.
The inert atmosphere is one of high-purity nitrogen, high-purity helium and high-purity argon; the heating rate of carbonization process is 0.5-10deg.C/min, the maximum carbonization temperature is 500-1100deg.C, and the maintenance time of the maximum carbonization temperature is 0.5-2hr.
In the step (2), the mass ratio of the carbonization catalyst to the deactivated catalyst is 1:25-80, the treatment fluid C is one of sodium peroxodisulfate, potassium peroxodisulfate, sodium monopersulfate or potassium monopersulfate aqueous solution, the mass fraction of the persulfate in the treatment fluid C is 0.5-10%, and the mass ratio of the total dry catalyst to the treatment fluid B is 1:10-50.
The catalyst treatment temperature is 30-80 ℃, the ultraviolet wavelength of the regeneration kettle is 180-300 nm, and the microwave treatment power is 200-2000W.
In the step (3), the solvent D is one of mixed liquid of formic acid and dipropylene glycol dimethyl ether, mixed liquid of acetic acid and dipropylene glycol dimethyl ether or mixed liquid of propionic acid and dipropylene glycol dimethyl ether, the mass ratio of the dry catalyst to the solvent D is 1:15-80, the microwave washing power is 500-1500W, and the washing temperature is 50-100 ℃.
In the mixed solution of the organic acid and the dipropylene glycol dimethyl ether, the mass fraction of the organic acid is 1% -15%.
In the step (4), the mass ratio of the dry catalyst to the deionized water is 1:15-80.
The regenerated catalyst is used for one of the reactions of preparing 2,2' -dichlorohydrazobenzene by selectively hydrogenating o-chloronitrobenzene, preparing 2-amino-4-methyl-5-chlorobenzenesulfonic acid by selectively hydrogenating 2-nitro-4-methyl-5-chlorobenzenesulfonic acid, preparing p-chloroaniline by selectively hydrogenating p-nitrochlorobenzene or preparing m-chloroaniline by selectively hydrogenating m-nitrochlorobenzene.
The method has the advantages of simplicity, high efficiency, environment friendliness, mild conditions and the like, can ensure the removal of organic macromolecules and simultaneously can keep the pore channel structure of the catalyst and the noble metal nanoparticle loading state, and the method is highly suitable for the characteristic of selective hydrogenation reaction of chloronitroaromatic hydrocarbon, so that the activity of the catalyst is effectively recovered, the application times of the catalyst is increased, and the use cost of the catalyst is obviously reduced.
(IV) description of the drawings
The invention is further described below with reference to the accompanying drawings.
FIG. 1 is a TEM photograph of fresh 5w% Pt/C catalyst Cat1-F of example 1;
FIG. 2 is a TEM photograph of the regenerated catalyst Cat1-U-R of example 1.
(Fifth) detailed description of the invention
The invention is further illustrated below with reference to examples.
Example 1: regeneration of 5w% Pt/C catalyst deactivated in selective hydrogenation of o-chloronitrobenzene to 2,2' -dichlorohydrazobenzene comprising the steps of:
(1) 10g of deactivated catalyst (marked as Cat 1-U) is dispersed into 50g of methanol solution containing 5% of N-butyl titanate and 5% of terephthalaldehyde, stirring and soaking are carried out at 50 ℃, after soaking is finished, the catalyst is filtered and transferred into a tubular atmosphere furnace, and is carbonized after being heated to 500 ℃ at a heating rate of 2 ℃/min under the protection of N 2, and a product (marked as N & Ti@Cat1-U) obtained after carbonization is cooled and stored for standby.
(2) 10G of N & Ti@Cat1-U and 250g of Cat1-U are added into a 10L regeneration kettle provided with an ultraviolet irradiation device and a microwave generation device, 2.5kg of aqueous solution containing 5% sodium peroxodisulfate is added, regeneration treatment is carried out under the action of ultraviolet radiation with the wavelength of 200nm, the treatment temperature is 50 ℃, the microwave power is 1000W, and the treated feed liquid is filtered by pressing nitrogen into a precise filter.
(3) And (3) backflushing the catalyst in the filter into a regeneration kettle by adopting 5kg of dipropylene glycol dimethyl ether mixed solution containing 10% formic acid, starting stirring under the auxiliary action of 1000W microwaves for washing, pressing the washed feed liquid into a precise filter by nitrogen for filtering, and recovering filtrate for later use.
(4) The catalyst in the filter was back flushed into the regeneration tank with 5kg deionized water, and after flushing clean, the regenerated wet-based catalyst (designated Cat 1-U-R) was obtained.
The regenerated catalyst is subjected to performance evaluation: 54g of o-chloronitrobenzene, 28g of toluene, 0.216g of regenerated catalyst Cat1-U-R (calculated on a dry basis), 27.5g of sodium hydroxide solution with the concentration of 17%, 0.216g of 2, 3-dichloro-1, 4-naphthoquinone and 0.432g of sodium dodecyl benzene sulfonate are added into a 500ml high-pressure reaction kettle, hydrogen is filled after nitrogen replacement, the temperature is raised to 65 ℃, and the pressure of the hydrogen is maintained to 2.0MPa until the reaction system is not judged to be the end of the reaction after hydrogen absorption. The catalyst-mixed reaction liquid is filtered to recover the catalyst. The catalyst was continuously applied 5 times without additional. And quantitatively analyzing the 5 batches of reaction liquid by adopting a high performance liquid chromatograph, and calculating the conversion rate of o-chloronitrobenzene and the purity of the product 2,2' -dichlorohydroazobenzene. The results were as follows:
The experimental results in the table show that the regenerated catalyst Cat1-U-R is continuously used for 5 times without being supplemented, the conversion rate of o-chloronitrobenzene can reach 100%, the purity of the 2,2' -dichlorohydrazobenzene is higher than 99%, the reaction time is basically unchanged along with the increase of the application times, the stability of the catalyst is superior, and compared with the catalyst before regeneration, the catalyst performance is obviously improved.
The fresh, deactivated and regenerated catalyst was subjected to comparative analysis using N 2 low temperature physical adsorption, ICP, CO chemisorption, with the following results:
Sample of Specific surface area/m 2g-1 Pore volume/cm 3g-1 Specific surface area of metal/m 2g-1
Cat1-F 1632.43 1.65 158
Cat1-U 712.58 0.54 70
Cat1-U-R 1616.20 1.62 155
As can be seen from the characterization results of the above table, compared with the fresh catalyst Cat1-F, the specific surface area of the deactivated catalyst Cat1-U is reduced by 56.3%, the pore volume is reduced by 67.3%, and the specific surface area of the metal is reduced by 55.7%. The specific surface area of the regenerated catalyst Cat1-U-R can be restored to 99% of the fresh catalyst, the pore volume can be restored to 98% of the fresh catalyst, and the specific surface area of the metal can be restored to 98% of the fresh catalyst. The regeneration method can effectively remove the organic impurities attached to the catalyst, realize the cleaning of pore channels and release the active sites of the catalyst.
The Pt loading of fresh, deactivated and regenerated catalyst was analyzed by comparison using inductively coupled plasma atomic emission spectroscopy, with the following results:
Cat1-F Cat1-U Cat1-U-R
Actual load/wt.% 4.97 4.96 4.96
The ICP characterization result shows that the actual load and the actual load of the regenerated catalyst are very little different from those of the fresh catalyst, and the fact that the regeneration method does not influence the load of metal and the loss of metal Pt in the regeneration process is shown.
The morphology and microstructure of the fresh and regenerated catalysts were characterized by Transmission Electron Microscopy (TEM), the results of which are shown in fig. 1 and 2.TEM images show that the particle size and dispersion of the regenerated catalyst and the fresh catalyst are almost unchanged, which indicates that the regeneration method does not grow or agglomerate Pt particles.
By combining the characterization analysis and the reaction evaluation, the regeneration method can effectively recover the specific surface area, the pore volume and the specific surface area of active metal of the catalyst, greatly improve the catalytic performance and can not adversely affect the metal loading capacity and the dispersion state of the metal nano particles of the catalyst.
Example 2: 3w% of Pd/C catalyst deactivated in the selective hydrogenation of o-chloronitrobenzene to prepare 2,2' -dichlorohydrazobenzene is regenerated, comprising the steps of:
(1) 10g of deactivated catalyst (Cat 2-U) is dispersed into 50g of methanol solution containing 15% of N-butyl titanate and 15% of terephthalaldehyde, stirring and dipping are carried out at 80 ℃, the catalyst is filtered and transferred into a tubular atmosphere furnace after the dipping is finished, the temperature is raised to 800 ℃ at a heating rate of 5 ℃/min under the protection of N 2, carbonization treatment is carried out for 2 hours, and a product (recorded as N & Ti@Cat2-U) obtained after carbonization is cooled and stored for standby.
(2) 10G of N & Ti@Cat2-U and 300g of Cat2-U are added into a 10L regeneration kettle provided with an ultraviolet irradiation device and a microwave generation device, 3kg of aqueous solution containing 5% potassium peroxodisulfate is added, regeneration treatment is carried out under the action of ultraviolet radiation with the wavelength of 255nm, the treatment temperature is 50 ℃, the microwave power is 2000W, and the treated feed liquid is pressed into a precise filter by nitrogen to be filtered.
(3) And (3) backflushing the catalyst in the filter into a regeneration kettle by adopting 6kg of dipropylene glycol dimethyl ether mixed solution containing 10% acetic acid, starting stirring under the auxiliary action of 1500W microwaves for washing, pressing the washed feed liquid into a precise filter by nitrogen, filtering, and recovering filtrate for later use.
(4) The catalyst in the filter was back flushed into the regeneration tank with 6kg deionized water, and after flushing clean, the regenerated wet-based catalyst (designated Cat 2-U-R) was obtained.
Performance evaluation of the regenerated catalyst: 54g of o-chloronitrobenzene, 28g of toluene, 0.216g of regenerated catalyst Cat2-U-R (calculated on a dry basis), 27.5g of sodium hydroxide solution with the concentration of 17%, 0.216g of 2, 3-dichloro-1, 4-naphthoquinone and 0.432g of sodium dodecyl benzene sulfonate are added into a 500ml high-pressure reaction kettle, hydrogen is filled after nitrogen replacement, the temperature is raised to 65 ℃, and the pressure of the hydrogen is maintained to 2.0MPa until the reaction system is not judged to be the end of the reaction after hydrogen absorption. The catalyst-mixed reaction liquid is filtered to recover the catalyst. The catalyst was continuously applied 5 times without additional. And quantitatively analyzing the 5 batches of reaction liquid by adopting a high performance liquid chromatograph, and calculating the conversion rate of o-chloronitrobenzene and the purity of the product 2,2' -dichlorohydroazobenzene. The results were as follows:
The experimental results in the table show that the regenerated catalyst Cat2-U-R is continuously used for 5 times without being supplemented, the conversion rate of the o-nitrochlorobenzene is close to 100%, the purity of the 2,2' -dichloro hydroazobenzene product is higher than 99%, the reaction time is basically unchanged along with the increase of the application times, the stability of the catalyst is superior, and compared with the catalyst before regeneration, the catalyst performance is obviously improved.
Example 3: comparative experiments on regeneration methods
(1) Directly adding 250g of Cat1-U into a 10L regeneration kettle provided with an ultraviolet irradiation device and a microwave generation device, adding 2.5kg of aqueous solution containing 5% sodium peroxodisulfate, carrying out regeneration treatment under the action of ultraviolet radiation with the wavelength of 200nm, wherein the treatment temperature is 50 ℃, and pressing the treated feed liquid with the microwave power of 1000W into a precise filter by nitrogen to filter.
(2) Subsequent regeneration experiments were performed according to steps (3), (4) of example 1. Catalyst performance evaluation was performed on the regenerated catalyst (designated Cat 1-U-R1): the evaluation method and the analysis method were the same as in example 1. The results were as follows:
As can be seen from the experimental results in the above table, the catalyst Cat1-U-R1 regenerated in this example had an o-chloronitrobenzene conversion of only 32.8% of Cat1-U-R compared to the catalyst regenerated in example 1. Characterization analysis of the structural properties of Cat1-U-R1 by BET, CO chemisorption gave the following results:
Sample of Specific surface area/m 2g-1 Pore volume/cm 3g-1 Specific surface area of metal/m 2g-1
Cat1-F 1632.43 1.65 158
Cat1-U 712.58 0.54 70
Cat1-U-R 1616.20 1.62 155
Cat1-U-R1 852.33 0.84 98
According to BET and CO chemisorption characterization results, the specific surface area of the regenerated catalyst Cat1-U-R1 of the embodiment is only 52.2% of that of the fresh catalyst, the pore volume is only 50.9% of that of the fresh catalyst, and the specific surface area of the metal is only 62% of that of the fresh catalyst. Therefore, the regenerated catalyst of this embodiment example cannot fully recover the catalytic performance of the catalyst.
Implementation example 4: comparative experiments on regeneration methods
(1) 10G of deactivated catalyst (marked as Cat 1-U) is dispersed into 50g of methanol solution containing 5% terephthalaldehyde, stirring and soaking are carried out at 50 ℃, after soaking is finished, the catalyst is filtered and transferred into a tubular atmosphere furnace, and is carbonized after being heated to 500 ℃ at a heating rate of 2 ℃/min under the protection of N 2, and a product (marked as N@Cat1-U) obtained after carbonization is cooled and stored for standby.
The regenerated catalyst Cat1-U-R2 was then obtained by the treatment according to the steps (2), (3) and (4) in example 1, and the performance evaluation was conducted by the method in example 1, with the following results:
As can be seen from the above table, the conversion of o-chloronitrobenzene of catalyst Cat1-U-R2 increased by 23% and the conversion of o-chloronitrobenzene of Cat1-U-R increased by 44.7% as compared to the deactivated catalyst Cat 1-U-R. This indicates that the lack of precursors to participate in catalyst regeneration does not fully restore the catalytic performance of the catalyst.
Implementation example 5: comparative experiments on regeneration methods
(1) 10G of deactivated catalyst (marked as Cat 1-U) is added into 50g of methanol solution containing 5% of N-butyl titanate, stirring and soaking are carried out at 50 ℃, after soaking is finished, the catalyst is filtered and transferred into a tubular atmosphere furnace, and is carbonized after being heated to 500 ℃ at a heating rate of 2 ℃/min under the protection of N 2, and the carbonized product (marked as Ti@Cat1-U) is cooled and stored for standby.
The regenerated catalyst Cat1-U-R3 was then obtained by the treatment according to the steps (2), (3) and (4) in example 1, and the performance evaluation was conducted by the method in example 1, with the following results:
as can be seen from the above table, the conversion of o-chloronitrobenzene of catalyst Cat1-U-R3 increased by 26.1% and the conversion of o-chloronitrobenzene of Cat1-U-R increased by 44.7% as compared to the deactivated catalyst Cat 1-U-R. This indicates that the lack of a stabilizing solution to participate in catalyst regeneration does not fully restore the catalytic performance of the catalyst.
Quantitative and qualitative analyses of N@Cat1-U in practical examples 1 and 4 and Ti@Cat1-U in practical example 5 using elemental analysis and XPS revealed that: the nitrogen element content of N@Cat1-U is 3.4%, nitrogen-containing species mainly comprise pyridine, graphite and oxidation nitrogen atoms, and the nitrogen element content of Ti@Cat1-U is only 0.5%.
Example 6: comparative experiments on regeneration methods
The same regeneration method as in example 1 was used to regenerate the deactivated catalyst Cat1-U, the only difference from the technical scheme of example 1 being that in step (3), the washing solvent used was pure dipropylene glycol dimethyl ether.
The regenerated catalyst was designated Cat1-U-R4. Catalyst performance evaluation was performed on the regenerated Cat 1-U-R4: the evaluation method and the analysis method were the same as in example 1. The results were as follows:
As can be seen from the experimental results of the above table, the o-chloronitrobenzene conversion of catalyst Cat1-U-R4 was increased by 17.2% and the o-chloronitrobenzene conversion of Cat1-U-R was increased by 44.7% as compared to the deactivated catalyst Cat 1-U-R. Characterization analysis of the structural properties of Cat1-U-R4 by BET, CO chemisorption gave the following results:
Sample of Specific surface area/m 2g-1 Pore volume/cm 3g-1 Specific surface area of metal/m 2g-1
Cat1-F 1632.43 1.65 158
Cat1-U 712.58 0.54 70
Cat1-U-R 1616.20 1.62 155
Cat1-U-R4 1312.55 1.36 99
As can be seen from the experimental results in the table above, the specific surface area of Cat1-U-R4 is 80.4% of the fresh catalyst, the pore volume is 82.4% of the fresh catalyst, but the specific surface area of metals of Cat1-U-R4 is only 62.7% of the fresh catalyst.
Comparative analysis of Temperature Programmed Desorption (TPD) of fresh and regenerated catalyst using a chemisorber revealed that: the fresh catalyst Cat1-F has no desorption peak of NH 3, the regenerated Cat1-U-R has no desorption peak of NH 3 by the method in example 1, and the regenerated Cat1-U-R4 has obvious desorption peak of NH 3.
By combining the characteristics, in the step (3), the dipropylene glycol dimethyl ether is simply used for washing, so that most of organic impurities can be removed, but the organic acid is not involved in catalyst regeneration, ammonia adsorbed on the active site of the metal cannot be removed, and the catalytic activity of the metal Pt cannot be recovered.
Example 7: comparative experiments on regeneration methods
(1) 10G of catalyst Cat1-U is accurately weighed, 60ml of nitric acid solution with the concentration of 5% -20% is added, and the mixture is oscillated for 2 hours in a constant temperature water bath at 25 ℃. And then filtering, washing and drying to constant weight. The treated catalyst was designated Cat1-U-R5 and was evaluated according to the evaluation method and the analysis method of example 1.
(2) 10G of catalyst Cat1-U is accurately weighed, 60ml of hydrogen peroxide solution with the concentration of 10% -30% is added, and the mixture is oscillated for 2 hours in a constant temperature water bath at 25 ℃. And then filtering, washing and drying to constant weight. The treated catalyst was designated Cat1-U-R6 and was evaluated according to the evaluation method and the analysis method of example 1. The results were as follows:
The experimental results in the above table show that: compared with the deactivated catalyst Cat1-U-R, the o-chloronitrobenzene conversion rate of the catalyst Cat1-U-R5 is increased by 30.8%, the o-chloronitrobenzene conversion rate of the catalyst Cat1-U-R6 is increased by 31.2%, and the o-chloronitrobenzene conversion rate of the catalyst Cat1-U-R is increased by 44.7%. Therefore, the analysis of structural property characterization of Cat1-U-R5 and Cat1-U-R6, including specific surface area, pore volume, specific metal surface area and the measurement of Pt content of three catalysts by ICP, is carried out as follows:
Sample of Specific surface area/m 2g-1 Pore volume/cm 3g-1 Specific surface area of metal/m 2g-1
Cat1-U-R 1616.20 1.62 155
Cat1-U-R5 1342.31 1.39 122
Cat1-U-R6 1365.69 1.45 128
Cat1-U 712.58 0.54 70
Cat1-F 1632.43 1.65 158
Sample of Actual load/wt.%
Cat1-U-R 4.96
Cat1-U-R5 2.23
Cat1-U-R6 2.35
Cat1-U 4.96
Cat1-F 4.97
From the above table the following conclusions can be drawn: the specific surface area and the pore volume of the regenerated catalyst are close to those of fresh catalyst, and the gap between the catalyst subjected to the conventional oxidant oxidation treatment and the fresh catalyst is larger. According to analysis of the characterization result, the specific surface area, the pore volume and the specific surface area of the catalyst after the oxidation treatment are recovered, but the level of the fresh catalyst is still not reached, and the catalyst after the oxidation treatment has serious Pt loss phenomenon, which is the main reason for poor catalyst activity. .
Example 8: comparative experiments on regeneration methods
(1) 10G of catalyst Cat1-U was weighed accurately, 60ml of methanol was added thereto, and the mixture was refluxed with stirring at 85℃for 3 hours. And then filtering, washing and drying to constant weight. The treated catalyst was designated Cat1-U-R7 and was evaluated according to the evaluation method and the analysis method of example 1.
(2) 10G of catalyst Cat1-U was weighed accurately, 60ml of acetone was added thereto, and the mixture was refluxed with stirring at 85℃for 3 hours. And then filtering, washing and drying to constant weight. The treated catalyst was designated Cat1-U-R8 and was evaluated according to the evaluation method and the analysis method of example 1.
(3) 10G of catalyst Cat1-U was accurately weighed, 60ml of dipropylene glycol dimethyl ether was added thereto, and the mixture was refluxed with stirring at 180℃for 3 hours. And then filtering, washing and drying to constant weight. The treated catalyst was designated Cat1-U-R9 and was evaluated according to the evaluation method and the analysis method of example 1.
The experimental results in the above table show that: compared with the deactivated catalyst Cat1-U-R, the o-chloronitrobenzene conversion rate of the catalyst Cat1-U-R7 is increased by 4.9%, the o-chloronitrobenzene conversion rate of the catalyst Cat1-U-R8 is increased by 4.1%, the o-chloronitrobenzene conversion rate of the catalyst Cat1-U-R9 is increased by 14.9%, and the o-chloronitrobenzene conversion rate of the catalyst Cat1-U-R is increased by 44.7%. Therefore, the structural characterization analysis of Cat1-U-R7, cat1-U-R8 and Cat1-U-R9, including specific surface area, pore volume and specific metal surface area, was performed to determine the following results:
Sample of Specific surface area/m 2g-1 Pore volume/cm 3g-1 Specific surface area of metal/m 2g-1
Cat1-U-R 1616.20 1.62 155
Cat1-U-R7 824.67 0.78 89
Cat1-U-R8 816.33 0.69 85
Cat1-U-R9 1130.52 1.33 117
Cat1-U 712.58 0.54 70
Cat1-F 1632.43 1.65 158
From the above table, the specific surface area of the catalyst Cat1-U-R7 is only 50.5% of that of the fresh catalyst, the pore volume is only 47.3% of that of the fresh catalyst, and the specific surface area of the metal is only 56.3% of that of the fresh catalyst. The specific surface area of the catalyst Cat1-U-R8 is only 50.0% of that of the fresh catalyst, the pore volume is only 41.8% of that of the fresh catalyst, and the specific surface area of the metal is only 53.8% of that of the fresh catalyst. The specific surface area of the catalyst Cat1-U-R9 is only 69.3% of that of the fresh catalyst, the pore volume is only 80.6% of that of the fresh catalyst, and the specific surface area of the metal is only 74.1% of that of the fresh catalyst. Therefore, it is difficult to obtain a remarkable regeneration effect only by washing with a conventional organic solvent, and it is not possible to effectively recover the impurities deposited by the surface adhesion of the catalyst.

Claims (9)

1. A regeneration method of a chloronitroaromatic hydrocarbon selective hydrogenation catalyst takes a catalyst with reduced catalytic performance generated in the process of preparing chloroaromatic amine by selective hydrogenation by taking chloronitroaromatic hydrocarbon as a raw material as a treatment object, and is characterized by comprising the following steps:
⑴ Adding a part of deactivated catalyst into the mixed alcohol solution of the precursor A and the stabilizer B, heating, stirring and soaking, filtering the catalyst after soaking, transferring the catalyst into a tubular atmosphere furnace, heating and carbonizing in an inert atmosphere according to a programmed temperature, cooling the carbonized product, and preserving for later use;
the deactivated catalyst is one of Pt, pd and Ru loaded by activated carbon, nano porous carbon, porous carbon spheres, carbon nano tubes or activated carbon fibers;
The precursor A is one of n-propyl titanate, isopropyl titanate, n-butyl titanate and isobutyl titanate; the stabilizer B is one of terephthalaldehyde, isophthalaldehyde or o-phthalaldehyde; the solvent alcohol is one of methanol, ethanol or isopropanol;
⑵ Adding the carbonized catalyst and the deactivated catalyst obtained in the step ⑴ into a regeneration kettle provided with an ultraviolet light generating device and a microwave generating device according to a certain dry basis mass ratio, adding a treatment liquid C, starting stirring under the ultraviolet light irradiation condition to perform regeneration treatment, and pressing the treated liquid into a precise filter by nitrogen to filter;
The treatment fluid C is one of aqueous solutions of sodium peroxodisulfate, potassium peroxodisulfate, sodium monopersulfate or potassium monopersulfate; ⑶ The catalyst in the filter is backflushed into a regeneration kettle by adopting a solvent D, stirring is started under the auxiliary action of microwaves to wash, the washed feed liquid is pressed into a precise filter by nitrogen to be filtered, and filtrate is recovered for later use;
The solvent D is one of mixed solution of formic acid and dipropylene glycol dimethyl ether, mixed solution of acetic acid and dipropylene glycol dimethyl ether or mixed solution of propionic acid and dipropylene glycol dimethyl ether;
⑷ And (3) backflushing the catalyst in the filter into a regeneration kettle by adopting deionized water, and filtering after washing to obtain the regenerated wet-based catalyst.
2. The method for regenerating a chloronitroaromatic selective hydrogenation catalyst according to claim 1, wherein: in the step ⑴, the content of the precursor A in the alcohol solution is 1-30%, and the content of the stabilizer B in the solution is 5-30%; the mass ratio of the dry-base deactivated catalyst to the alcohol solution is 1:4-20, and the impregnation temperature is 50-80 ℃.
3. The method for regenerating a chloronitroaromatic selective hydrogenation catalyst according to claim 1, wherein: in step ⑴, the inert atmosphere is one of high-purity nitrogen, high-purity helium and high-purity argon; the heating rate of carbonization process is 0.5-10deg.C/min, the maximum carbonization temperature is 500-1100deg.C, and the maintenance time of the maximum carbonization temperature is 0.5-2hr.
4. The method for regenerating a chloronitroaromatic selective hydrogenation catalyst according to claim 1, wherein: in step ⑵, the mass ratio of the carbonized catalyst to the deactivated catalyst is 1:25-80, the mass fraction of the persulfate in the treatment fluid C is 0.5-10%, and the mass ratio of the total dry catalyst to the treatment fluid C is 1:10-50.
5. The method for regenerating a chloronitroaromatic selective hydrogenation catalyst according to claim 1, wherein: in the step ⑵, the catalyst treatment temperature is 30-80 ℃, the ultraviolet light wavelength in the regeneration kettle is 180-300 nm, and the microwave treatment power is 200-2000W.
6. The method for regenerating a chloronitroaromatic selective hydrogenation catalyst according to claim 1, wherein: in the step ⑶, the mass ratio of the dry catalyst to the solvent D is 1:15-80, the microwave washing power is 500W-1500W, and the washing temperature is 50-100 ℃.
7. The method for regenerating a chloronitroaromatic selective hydrogenation catalyst according to claim 1, wherein: in step ⑷, the mass ratio of the dry catalyst to deionized water is 1:15-80.
8. The method for regenerating a chloronitroaromatic selective hydrogenation catalyst according to claim 6, wherein: in the mixed solution of formic acid and dipropylene glycol dimethyl ether, the mixed solution of acetic acid and dipropylene glycol dimethyl ether or the mixed solution of propionic acid and dipropylene glycol dimethyl ether, the mass fraction of formic acid, acetic acid or propionic acid is 1-15%.
9. The use of the regenerated catalyst obtained by the regeneration method according to claim 1 in the preparation of chloro aromatic amine by selective hydrogenation of chloro nitroaromatic hydrocarbon, which is characterized in that: the reaction is one of the reactions of preparing 2,2' -dichlorohydrazobenzene by selectively hydrogenating o-chloronitrobenzene, preparing 2-amino-4-methyl-5-chlorobenzenesulfonic acid by selectively hydrogenating 2-nitro-4-methyl-5-chlorobenzenesulfonic acid and preparing p-chloroaniline by selectively hydrogenating p-nitrochlorobenzene or preparing m-chloroaniline by selectively hydrogenating m-nitrochlorobenzene.
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RU2673798C9 (en) * 2013-07-24 2019-04-08 Басф Се Regeneration of titanium-containing zeolite
CN109701669B (en) * 2019-02-27 2021-06-25 青岛科技大学 Regeneration method of hydrogenation catalyst for preparing arylamine antioxidant
CN110550815A (en) * 2019-07-29 2019-12-10 郑州大学 Device and method for advanced treatment of old landfill leachate

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CA1244789A (en) * 1984-08-16 1988-11-15 James E. Lewis Large pore catalysts for heavy hydrocarbon conversion
CN106732655A (en) * 2016-12-05 2017-05-31 江苏肯创催化剂再生技术有限公司 A kind of arsenic poisoning SCR denitration renovation process

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