A supported iron-ruthenium catalyst and its use in the synthesis of m-dichlorobenzene and / or p-dichlorobenzene

Abstract

This invention belongs to the field of catalyst technology, specifically relating to a supported iron-ruthenium catalyst and its application in the synthesis of m-dichlorobenzene and / or para-dichlorobenzene. The iron-ruthenium catalyst comprises a support and iron and ruthenium supported on the support. The support comprises quaternary ammonium salt-modified diatomaceous earth. Based on the total weight of the catalyst, the mass percentage of iron is 5-15%, and the mass percentage of ruthenium is 3-9%. The abundant active sites on the surface of the quaternary ammonium salt-modified diatomaceous earth support can significantly improve the catalytic activity and selectivity for m-dichlorobenzene and / or para-dichlorobenzene, without the formation of trichlorobenzene. The catalyst lifetime is 5-8 times longer than that of iron catalysts. The product can be separated and purified by stripping, distillation, and crystallization. The process is simple and can obtain high-purity m-dichlorobenzene and para-dichlorobenzene products.

Description

Technical Field

[0001] This invention belongs to the field of catalyst technology, specifically relating to a supported iron-ruthenium catalyst and its application in the synthesis of m-dichlorobenzene and / or p-dichlorobenzene. Background Technology

[0002] m-Dichlorobenzene is an important organic synthesis raw material, widely used as an intermediate in the dye, pharmaceutical, and pesticide industries. It is a raw material for the fungicides imidacloprid, propiconazole, and eticonazole, as well as the insecticide chlorpyrifos. p-Dichlorobenzene, abbreviated as PDCB, is mainly used in the synthesis of dyes (GG and 3GL, Reactive Yellow and RC) and as an intermediate in pesticides. It is used as a fumigant insecticide, a mothproofing agent, a mildew inhibitor, and an air deodorizer. 65%-70% is used in the manufacture of mothballs, and a small amount is used in special pressure lubricants and corrosion inhibitors. It also has pharmaceutical uses and can be used as a solvent. p-Dichlorobenzene is also a major raw material for the production of polyphenylene sulfide (PPS), the world's sixth largest engineering plastic. PPS is corrosion-resistant, non-toxic, and dimensionally stable. PPS has wide applications in electronics, aerospace, and automotive industries, and has excellent market prospects.

[0003] Industrially, the common method for producing m-dichlorobenzene and para-dichlorobenzene involves chlorinating benzene or further chlorinating chlorobenzene to obtain a mixture of para-dichlorobenzene, o-dichlorobenzene, and m-dichlorobenzene. This mixture is then separated and purified to obtain various dichlorobenzene isomers. However, due to the ortho- and para-directing effects of chlorine, the m-dichlorobenzene content in the product is very low.

[0004] Currently, methods for separating dichlorobenzene isomers mainly include distillation, recrystallization, emulsion crystallization, dissolution crystallization, distillation-falling film crystallization coupling, bromination, liquid-liquid extraction, isomerization, and molecular sieve adsorption. These methods generally suffer from high energy consumption, long process flows, high operational difficulty, and high production costs, and also produce products with low purity, making industrialization difficult. Furthermore, during chlorination, factors such as reactor type, feed ratio, reaction temperature, and catalyst significantly influence the proportion of dichlorobenzene isomers. Finding suitable reaction conditions to promote selective chlorination at the meta-position is an urgent problem to be solved. Current research on the directional chlorination of dichlorobenzene mostly focuses on the proportion of ortho-products, with few reports on the synthesis and process optimization of meta-dichlorobenzene. Summary of the Invention

[0005] To address the problems existing in the current synthesis of m-dichlorobenzene, this invention provides a quaternary ammonium salt modified iron-ruthenium catalyst. Using this catalyst, the directional chlorination of benzene can be achieved, significantly increasing the proportion of m-dichlorobenzene in the chlorination liquid, and greatly improving product selectivity and economic benefits.

[0006] The technical solution of the present invention is as follows:

[0007] In a first aspect, the present invention provides a supported iron-ruthenium catalyst, the iron-ruthenium catalyst comprising a support and iron and ruthenium supported on the support, the support comprising quaternary ammonium salt modified diatomite.

[0008] The abundant active sites on the surface of diatomaceous earth carriers modified with quaternary ammonium salts can significantly improve catalytic activity and selectivity for m-dichlorobenzene and / or p-dichlorobenzene, without the generation of trichlorobenzene, and the catalyst lifetime is 5 to 8 times longer than that of iron catalysts.

[0009] As a specific embodiment of the present invention, based on the total weight of the catalyst, the mass percentage of iron in the catalyst is 5-15%, and the mass percentage of ruthenium is 3-9%.

[0010] As a specific embodiment of the present invention, based on the total weight of the catalyst, the mass percentage of iron in the catalyst is 8-12%, and the mass percentage of ruthenium is 5-7%.

[0011] As a specific embodiment of the present invention, the mass ratio of quaternary ammonium salt to diatomite in the carrier is 1-5:60, preferably 1-3:60.

[0012] As a specific embodiment of the present invention, the catalyst further includes an auxiliary agent.

[0013] As a specific embodiment of the present invention, the mass percentage of the auxiliary agent is 1-5%, preferably 1.5-4%, and more preferably 2-2.6%.

[0014] As a specific embodiment of the present invention, the additive includes at least one of ZnO, MgO, NiO, and CuO.

[0015] Iron is a traditional catalyst for benzene chlorination. Adding ruthenium can synergistically enhance the catalytic selectivity of iron. The additives are used to improve the activity and lifespan of the catalyst.

[0016] As a specific embodiment of the present invention, the bulk density of the quaternary ammonium salt modified diatomite is 0.2-0.8 g / mL, preferably 0.4-0.6 g / mL;

[0017] As a specific embodiment of the present invention, the quaternary ammonium salt modified diatomite contains not less than 90 wt% SiO2 and 2-6 wt% Al2O3; preferably, the SiO2 content is 90-98 wt%.

[0018] As a specific embodiment of the present invention, the quaternary ammonium salt is selected from at least one of tetramethylammonium chloride, tetraethylammonium chloride, tetrabutylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium iodide and dodecyltrimethylammonium chloride; preferably, the quaternary ammonium salt is selected from tetramethylammonium chloride.

[0019] The quaternary ammonium salt modified diatomite of this application has a bulk density of 0.2-0.8 g / mL, which can better fix the active components iron and ruthenium; obtain a catalyst with a long lifespan; and facilitate subsequent filling and use.

[0020] As a specific embodiment of the present invention, the preparation method of the quaternary ammonium salt modified diatomite includes: dissolving the quaternary ammonium salt, mixing it with diatomite, and then drying and calcining it to obtain the diatomite.

[0021] As a specific embodiment of the present invention, the preparation method includes: spraying a quaternary ammonium salt solution onto diatomaceous earth, separating and screening it, drying it, calcining it, and adding a binder to form it.

[0022] In a specific embodiment of the present invention, the separation and screening is cyclone separation.

[0023] As a specific embodiment of the present invention, cyclone separation yields particles with a diameter of 6-12 μm, preferably 8-10 μm.

[0024] As a specific embodiment of the present invention, the calcination conditions include calcination at 300℃-450℃ for 1-3 hours.

[0025] As a specific embodiment of the present invention, the solvent in the quaternary ammonium salt solution includes at least one of water and alcohol.

[0026] As a specific embodiment of the present invention, the adhesive is selected from at least one of montmorillonite, attapulgite, and methylcellulose.

[0027] A shaped catalyst support is obtained by using an adhesive, and the resulting modified diatomaceous earth is a hollow cylinder, which is easy to fill.

[0028] Secondly, the present invention provides a method for preparing a supported iron-ruthenium catalyst, which is prepared by solution impregnation. The method involves mixing and impregnating an aqueous solution containing an iron salt, a ruthenium salt, and an optional soluble salt corresponding to an auxiliary agent with a support, followed by calcination.

[0029] This application utilizes a supported catalyst prepared from modified diatomaceous earth, exhibiting stable catalytic performance, high mechanical strength, and minimal risk of loss into the reaction solution. The synthesis process is mild, and the catalyst is unaffected by moisture in the benzene raw material, preventing the loss of active components. Dehydration and drying of the benzene are unnecessary, and the chlorination solution contains no impurities such as ferric chloride commonly found in traditional processes. No water washing or neutralization steps are required, resulting in a reduction of consumption per ton of product by more than 50%.

[0030] Thirdly, the present invention provides a method for preparing p-dichlorobenzene and / or m-dichlorobenzene, using the above-mentioned supported iron-ruthenium catalyst or the supported iron-ruthenium catalyst prepared by the above method.

[0031] As a specific embodiment of the present invention, the above preparation method includes the following steps:

[0032] (1) Benzene reacts with chlorine gas to undergo chlorination;

[0033] (2) After the reaction in step (1) is completed, the gas and liquid are separated, and the liquid phase is stripped, crystallized and distilled to obtain m-dichlorobenzene and / or p-dichlorobenzene, respectively.

[0034] As a specific embodiment of the present invention, the conditions for the chlorination reaction include: a molar ratio of benzene to chlorine of 2-3; a reaction temperature of 90-100℃; and a pressure of 0.1-0.4MPa.

[0035] As a specific embodiment of the present invention, the gas phase in step (2) is further processed to obtain hydrochloric acid.

[0036] The beneficial effects of this invention are:

[0037] 1) The supported iron-ruthenium catalyst provided by this invention uses quaternary ammonium salt-modified diatomaceous earth as a support. Its abundant surface active sites significantly improve the catalyst's catalytic activity and selectivity for dichlorobenzene, without producing trichlorobenzene. Furthermore, the catalyst exhibits high selectivity for m-dichlorobenzene and p-dichlorobenzene, has low manufacturing cost, and a lifespan 5-8 times longer than iron catalysts. The product can be separated and purified using stripping, distillation, and crystallization; the process is simple and can yield high-purity m-dichlorobenzene and p-dichlorobenzene products.

[0038] 2) The supported iron-ruthenium catalyst provided by this invention is used in the preparation of m-dichlorobenzene / p-dichlorobenzene. The synthesis process conditions are mild, the catalyst is not affected by the moisture in the raw benzene and thus the active components are not lost. There is no need to dehydrate and dry the benzene. The chlorination liquid does not contain impurities such as ferric chloride commonly found in traditional processes. There is no need for water washing and neutralization processes. The consumption per ton of product is reduced by more than 50%. Attached Figure Description

[0039] Figure 1 The chromatogram of the chlorinated solution of m-dichlorobenzene in Example 3 shows that the components in the 7-8 min range are m-dichlorobenzene, p-dichlorobenzene, and o-dichlorobenzene, respectively. Detailed Implementation

[0040] The present invention will be further described below with reference to specific embodiments, but this does not constitute any limitation on the present invention.

[0041] The present invention will be further illustrated below with reference to embodiments. These embodiments are merely illustrative and do not limit the scope of the invention.

[0042] Example 1

[0043] 1. A method for preparing a supported iron-ruthenium catalyst, comprising the following steps:

[0044] Preparation of S1 tetrapropylammonium chloride modified diatomite: 5g tetrapropylammonium chloride and 45g water were mixed with 300g diatomite; the mixture was further separated and purified in a hydrocyclone separator, and 6-10μm particles were obtained by separation and screening; then dried, calcined at 400℃ for 1h, and bonded with methylcellulose to obtain the modified diatomite carrier.

[0045] Characterization analysis showed that the bulk density of the tetrapropylammonium chloride-modified diatomite was 0.4 g / mL; the obtained modified diatomite was a hollow cylinder with a SiO2 content of 97 wt% and an Al2O3 content of 2 wt%.

[0046] Preparation of S2 catalyst: 17.4g of ferric chloride and 14.6g of ruthenium chloride were dissolved in 50g of water, added to 70g of tetrapropylammonium chloride-modified diatomaceous earth from step S1, and then an aqueous solution of zinc chloride, magnesium chloride and nickel chloride was added. The mixture was impregnated for 6 hours and then calcined at 450℃ for 4 hours.

[0047] The catalyst prepared contains 12% iron by mass, 7% ruthenium by mass, and additives of 1.0% ZnO, 0.4% MgO, and 0.1% NiO by mass.

[0048] The rest are carriers.

[0049] 2. A method for preparing m-dichlorobenzene and p-dichlorobenzene, comprising the following steps:

[0050] (1) Benzene and chlorine are continuously fed into a tubular reactor with a molar ratio of benzene to chlorine of 2.1. The bed is filled with the novel iron-ruthenium catalyst prepared in Part 1 of Example 1.

[0051] (2) The reaction temperature was controlled at 90℃, the pressure at 0.1MPa, and the residence time at 5min. After the reaction, the material was separated by gas-liquid separation and then analyzed by liquid (chlorinated liquid) chromatography.

[0052] The results of the chromatographic analysis in step (2) were as follows: monochlorobenzene content was 4.6 wt.%, m-dichlorobenzene content was 43.7 wt.%, p-dichlorobenzene content was 48.6 wt.%, o-dichlorobenzene content was 2.2 wt.%, water content was 0.9 wt.%, and no metal elements such as iron and ruthenium or other organic matter were detected in the chlorination solution.

[0053] (3) The chlorinated liquid is stripped to obtain a mixture of water, monochlorobenzene, m-dichlorobenzene, and p-dichlorobenzene. During stripping, the water content is 10% of the chlorinated liquid mass, and the stripping kettle temperature is 130℃. The stripping kettle residue is then distilled under reduced pressure to obtain o-dichlorobenzene. The stripping kettle top product is separated into phases and fed into a distillation column. Under conditions of a column bottom temperature of 120℃, an operating pressure of 20–30 kPa, and a reflux ratio of 8, monochlorobenzene and m-dichlorobenzene are successively collected. The distillation column bottom product is fed into a crystallization kettle, where the crystallization temperature is controlled at -18℃. After filtration and drying, p-dichlorobenzene is obtained.

[0054] The final results showed that m-dichlorobenzene had a purity of 99.87% and a yield of 40.5%; p-dichlorobenzene had a purity of 98.11% and a yield of 41.31%; after 250 days of continuous operation, the catalyst showed no significant loss and its catalytic activity remained normal.

[0055] Example 2

[0056] 1. A method for preparing a supported iron-ruthenium catalyst, comprising the following steps:

[0057] Preparation of tetrapropylammonium chloride modified diatomite: 10g of tetrapropylammonium bromide was mixed with 45g of water and then with 300g of diatomite; the mixture was further separated and purified in a hydrocyclone separator, and particles of 10-12μm were obtained by separation and screening; then dried, calcined at 300℃ for 3h, and bonded with montmorillonite to obtain the modified diatomite carrier.

[0058] Characterization analysis showed that the bulk density of the tetrapropylammonium chloride-modified diatomaceous earth was 0.6 g / mL. Transmission electron microscopy revealed that the modified diatomaceous earth was a hollow cylinder with a SiO2 content of 90 wt% and an Al2O3 content of 6 wt%. Preparation of catalyst S2: 16.2 g of ferric chloride and 7.0 g of ruthenium chloride were dissolved in 60 g of water and added to 50 g of the tetrapropylammonium chloride-modified diatomaceous earth from step S1. A saturated solution of zinc chloride, magnesium chloride, and nickel chloride was then added, and the mixture was impregnated for 6 h and calcined at 450 °C for 4 h. The prepared catalyst contained 8% iron and 5% ruthenium by mass, with additives including 2% ZnO, 1% MgO, and 1% NiO by mass; the remainder was a support.

[0059] 2. A method for preparing m-dichlorobenzene and p-dichlorobenzene, comprising the following steps:

[0060] (1) The benzene recovered from the petroleum benzene and chlorobenzene unit is mixed at a volume ratio of 6:1. Benzene and chlorine are continuously fed into a tubular reactor with a molar ratio of 3 for benzene to chlorine. The bed is filled with the novel iron-ruthenium catalyst prepared in Part 1 of Example 2.

[0061] (2) The reaction temperature was controlled at around 100℃, the pressure at 0.1MPa, and the residence time at 10min. After the reaction, the material was separated into gas and liquid and then analyzed by liquid (chlorinated liquid) chromatography.

[0062] The results of the chromatographic analysis in step (2) are as follows: after the reaction, the liquid contained 3.6 wt.% monochlorobenzene, 41.8 wt.% m-dichlorobenzene, 42.4 wt.% p-dichlorobenzene, 11.3 wt.% o-dichlorobenzene, and 0.9 wt.% water. No metal elements such as iron and ruthenium or other organic matter were detected in the chlorination liquid.

[0063] (3) The chlorinated liquid is stripped to obtain a mixture of water, monochlorobenzene, m-dichlorobenzene, and p-dichlorobenzene. During stripping, the water content is 30% of the chlorinated liquid mass, and the stripping kettle temperature is 105℃. After stripping, the material is separated and fed into a distillation column. Monochlorobenzene and m-dichlorobenzene are sequentially extracted under conditions of a column bottom temperature of 110℃, an operating pressure of 40–50 kPa, and a reflux ratio of 20. The distillation column bottom material enters a crystallization kettle, where the crystallization temperature is controlled at -10℃. After filtration and drying, p-dichlorobenzene is obtained.

[0064] The final results showed that m-dichlorobenzene had a purity of 99.90% and a yield of 37.3%, while p-dichlorobenzene had a purity of 98.33% and a yield of 38.5%. After 250 days of continuous operation, the catalyst showed no significant loss and its catalytic activity remained normal.

[0065] The recovered benzene contains some moisture, which is used as a raw material. Using the catalyst of this embodiment, the purity and yield of the product are both good, further demonstrating that the catalyst of this application has good water resistance and reusability.

[0066] Example 3

[0067] 1. A method for preparing a supported iron-ruthenium catalyst, comprising the following steps:

[0068] Preparation of tetrapropylammonium chloride modified diatomaceous earth: 8g of tetrapropylammonium chloride was dissolved in 45g of water and mixed with 300g of diatomaceous earth; further separation and purification were carried out in a hydrocyclone separator, and particles of 8-10μm were obtained by separation and screening; then dried, calcined at 350℃ for 2h, and bonded with montmorillonite to obtain the modified diatomaceous earth carrier; characterization analysis showed that the bulk density of the tetrapropylammonium chloride modified diatomaceous earth was 0.5g / mL; transmission electron microscopy showed that the modified diatomaceous earth was a hollow cylinder with a SiO2 content of 95wt% and an Al2O3 content of 4wt%.

[0069] Preparation of S2 catalyst: 16.2g ferric chloride and 7.0g ruthenium chloride were dissolved in 40g water and added to 50g tetrapropylammonium chloride modified diatomaceous earth from step S1. Then, an appropriate amount of zinc chloride, magnesium chloride, copper chloride and nickel chloride were added to form a saturated solution. The mixture was impregnated for 6h and calcined at 450℃ for 4h.

[0070] The catalyst prepared contains 10% iron and 6% ruthenium by mass. The additives include 1% ZnO, 1% MgO, 1% NiO, and 1% CuO by mass; the remainder is a support.

[0071] 2. A method for preparing m-dichlorobenzene and p-dichlorobenzene, comprising the following steps:

[0072] (1) The benzene recovered from the petroleum benzene and chlorobenzene unit is mixed at a volume ratio of 6:1. Benzene and chlorine are continuously fed into a tubular reactor with a molar ratio of benzene to chlorine of 2.5. The bed is filled with the novel iron-ruthenium catalyst prepared in Part 1 of Example 2.

[0073] (2) The reaction temperature was controlled at around 95℃, the pressure at 0.4MPa, and the residence time at 6min. After the reaction, the material was separated into gas and liquid components and analyzed by liquid (chlorinated liquid) chromatography.

[0074] The results of the chromatographic analysis in step (2) were as follows: the content of monochlorobenzene in the chlorination solution was 2.4 wt.%, m-dichlorobenzene was 50.8 wt.%, p-dichlorobenzene was 44.7 wt.%, o-dichlorobenzene was 1.3 wt.%, and water content was 0.8 wt. No metal elements such as iron and ruthenium or other organic matter were detected in the chlorination solution.

[0075] (3) The chlorinated liquid is stripped to obtain a mixture of water, monochlorobenzene, m-dichlorobenzene, and p-dichlorobenzene. During stripping, the water content is 30% of the chlorinated liquid mass, and the stripping kettle temperature is 105℃. After stripping, the material is separated and fed into a distillation column. Monochlorobenzene and m-dichlorobenzene are sequentially extracted under conditions of a column bottom temperature of 110℃, an operating pressure of 40–50 kPa, and a reflux ratio of 20. The distillation column bottom material enters a crystallization kettle, where the crystallization temperature is controlled at -10℃. After filtration and drying, p-dichlorobenzene is obtained.

[0076] The final results showed that m-dichlorobenzene had a purity of 99.95% and a yield of 45.7%, while p-dichlorobenzene had a purity of 98.66% and a yield of 43.6%. After 250 days of continuous operation, the catalyst showed no significant loss and its catalytic activity remained normal.

[0077] Example 4

[0078] Unlike Example 3, only ZnO was added as an additive, with a final mass percentage of 4%. The rest is the same as in Example 3.

[0079] The catalyst prepared contains 10% iron by mass, 6% ruthenium by mass, and 4% ZnO by mass as an additive.

[0080] The resulting chlorinated solution contained 2.0 wt.% monochlorobenzene, 47.6 wt.% m-dichlorobenzene, 42.3 wt.% p-dichlorobenzene, 4.2 wt.% o-dichlorobenzene, approximately 2.7 wt.% trichlorobenzene and other polychlorinated compounds, and 1.2 wt.% water.

[0081] The final results showed that m-dichlorobenzene had a purity of 99.92% and a yield of 45.9%, while p-dichlorobenzene had a purity of 98.78% and a yield of 41.16%. After 250 days of continuous operation, the catalyst showed no significant loss and its catalytic activity remained normal.

[0082] Compared with Example 3, the yield of p-dichlorobenzene was slightly lower, indicating that the addition of compounded additives is beneficial to improving the yield of p-dichlorobenzene. In addition, considering the content of each substance in the chlorination liquid, the compounded additives can reduce the production of o-dichlorobenzene and obtain more p-dichlorobenzene and m-dichlorobenzene.

[0083] Example 5

[0084] The difference from Example 3 is that no additives are added; otherwise, it is the same as Example 3.

[0085] The catalyst prepared contains 10% iron by mass, 6% ruthenium by mass, and the remainder is a support.

[0086] The resulting chlorinated solution contained 16.8 wt.% monochlorobenzene, 30.6 wt.% m-dichlorobenzene, 33.5 wt.% p-dichlorobenzene, 14.5 wt.% o-dichlorobenzene, and approximately 3.5 wt.% trichlorobenzene and other polychlorinated compounds.

[0087] Water content 1.1 wt.%.

[0088] The final results showed that m-dichlorobenzene had a purity of 99.91% and a yield of 28.5%, while p-dichlorobenzene had a purity of 98.50% and a yield of 31.1%. After 250 days of continuous operation, the catalyst experienced approximately 4% loss, and the catalytic activity decreased by approximately 8%.

[0089] Compared with Example 3, the yield of the obtained product was significantly lower, which was further attributed to the increased content of polychlorinated compounds such as monochlorobenzene, o-dichlorobenzene, and trichlorobenzene in the chlorination liquid, as well as the catalyst lifetime.

[0090] Comparative Example 1

[0091] Unlike Example 3, the diatomaceous earth is not modified. Everything else is the same as in Example 3.

[0092] The catalyst prepared contains 10% iron and 6% ruthenium by mass. The additives include 1% ZnO, 1% MgO, 1% NiO, 1% CuO, and the remainder is diatomaceous earth.

[0093] The resulting chlorinated liquid contained 17.5 wt.% monochlorobenzene, 28.4 wt.% m-dichlorobenzene, 37.5 wt.% p-dichlorobenzene, 11.5 wt.% o-dichlorobenzene, approximately 3.9 wt.% trichlorobenzene and other polychlorinated compounds, 1.2 wt.% water, and 0.06 wt.% ferric chloride and other salts.

[0094] The final results showed that m-dichlorobenzene had a purity of 99.90% and a yield of 22.4%, while p-dichlorobenzene had a purity of 98.15% and a yield of 32.6%.

[0095] Compared with Example 3, the yield of the obtained product decreased significantly, and the purity decreased slightly, indicating that the modification of the support is beneficial to improving the yield of dichlorobenzene and m-dichlorobenzene. Furthermore, the significantly reduced content of dichlorobenzene and m-dichlorobenzene in the chlorination liquid, along with the presence of salts such as ferric chloride, indicates that the modification of the support can stabilize catalyst components such as iron.

[0096] Comparative Example 2

[0097] The difference from Example 3 is that ruthenium chloride is not added. Everything else is the same as in Example 3.

[0098] The catalyst prepared contains 16% iron by mass, and the additives include: 1% ZnO, 1% MgO, 1% NiO, and 1% CuO by mass.

[0099] The rest are carriers.

[0100] The resulting chlorinated liquid contained 32.1 wt.% monochlorobenzene, 8.6 wt.% m-dichlorobenzene, 33.6 wt.% p-dichlorobenzene, 21.6 wt.% o-dichlorobenzene, approximately 2.9 wt.% trichlorobenzene and other polychlorinated compounds, 1.1 wt.% water, and 0.05 wt.% ferric chloride and other salts. After 250 days of continuous operation, the catalyst was lost by approximately 11%, and the catalytic activity decreased by 20%.

[0101] The final results showed that m-dichlorobenzene had a purity of 99.88% and a yield of 6.7%, while p-dichlorobenzene had a purity of 98.04% and a yield of 17.8%.

[0102] Compared to Example 3, the yields of p-dichlorobenzene and m-dichlorobenzene in the obtained product decreased significantly, and the purity of the product decreased slightly, indicating that the addition of ruthenium significantly improved the product yield. Furthermore, the substances in the chlorination solution were mainly monochlorobenzene and p-dichlorobenzene, but their content was not high, below 35%; after subsequent processing, the yield of p-dichlorobenzene was only 18%, indicating that the addition of ruthenium was beneficial in improving the yields of p-dichlorobenzene and m-dichlorobenzene. In addition, the presence of ferric chloride indicated that under the same carrier conditions, both iron and ruthenium are indispensable.

[0103] Comparative Example 3

[0104] The difference from Example 3 is that ferric chloride is not added. Everything else is the same as in Example 3.

[0105] The catalyst prepared contains 16% ruthenium by mass, and the additives include: 1% ZnO, 1% MgO, 1% NiO, and 1% CuO by mass.

[0106] The resulting chlorinated liquid contained 17.2 wt.% benzene, 45.2 wt.% monochlorobenzene, 3.6 wt.% m-dichlorobenzene, 17.5 wt.% p-dichlorobenzene, 14.6 wt.% o-dichlorobenzene, approximately 0.8 wt.% trichlorobenzene and other polychlorinated compounds, 1.1 wt.% water, and 0.02 wt.% ruthenium chloride and other salts. After 250 days of continuous operation, approximately 8% of the catalyst was lost, and the catalytic activity decreased by 15%.

[0107] The final results showed that m-dichlorobenzene had a purity of 99.78% and a yield of 2.4%, while p-dichlorobenzene had a purity of 98.05% and a yield of 15.3%.

[0108] Compared to Example 3, the yields of dichlorobenzene and m-dichlorobenzene in the obtained product were significantly lower, and the purity of the product was slightly lower, indicating that the addition of iron significantly improved the product yield. Furthermore, the presence of 17.2 wt.% benzene in the chlorination solution indicates that the reaction was incomplete, and the resulting chlorination solution was predominantly monochlorobenzene with a low content of dichlorobenzene. The presence of ruthenium chloride further demonstrates that, under the same support conditions, both iron and ruthenium are indispensable.

[0109] Any numerical value mentioned in this invention, if there is only a two-unit interval between any minimum and any maximum value, includes all values ​​that increase by one unit each time from the minimum to the maximum value. For example, if the amount of a component, or the value of a process variable such as temperature, pressure, or time, is stated as 50-90, in this specification it means specifically listing values ​​such as 51-89, 52-88… and 69-71 and 70-71, etc. For non-integer values, it may be appropriately considered that a unit is 0.1, 0.01, 0.001, or 0.0001. These are merely some specifically specified examples. In this application, in a similar manner, all possible combinations of numerical values ​​between the listed minimum and maximum values ​​are considered to have been disclosed.

[0110] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A supported iron-ruthenium catalyst, characterized in that, The iron-ruthenium catalyst includes a support and iron and ruthenium supported on the support, wherein the support comprises quaternary ammonium salt modified diatomite.

2. The supported iron-ruthenium catalyst according to claim 1, characterized in that, Based on the total weight of the catalyst, the mass percentage of iron in the catalyst is 5-15%, and the mass percentage of ruthenium is 3-9%; preferably, based on the total weight of the catalyst, the mass percentage of iron in the catalyst is 8-12%, and the mass percentage of ruthenium is 5-7%. And / or, the mass ratio of quaternary ammonium salt to diatomite in the carrier is 1-5:60, preferably 1-3:

60.

3. The supported iron-ruthenium catalyst according to claim 1 or 2, characterized in that, The catalyst also includes additives; Preferably, the mass percentage of the auxiliary agent is 1-5%, more preferably 1.5-4%, and even more preferably 2-2.6%. Preferably, the additive includes at least one of ZnO, MgO, NiO, and CuO.

4. The supported iron-ruthenium catalyst according to any one of claims 1-3, characterized in that, The bulk density of the quaternary ammonium salt modified diatomite is 0.2-0.8 g / mL, preferably 0.4-0.6 g / mL; And / or, the quaternary ammonium salt modified diatomite contains not less than 90 wt% SiO2 and 2-6 wt% Al2O3; preferably, the SiO2 content is 90-98 wt%. And / or, the quaternary ammonium salt is selected from at least one of tetramethylammonium chloride, tetraethylammonium chloride, tetrabutylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium iodide and dodecyltrimethylammonium chloride; preferably, the quaternary ammonium salt is selected from tetramethylammonium chloride.

5. The supported iron-ruthenium catalyst according to any one of claims 1-4, characterized in that, The method for preparing the quaternary ammonium salt modified diatomite includes: preparing a quaternary ammonium salt solution, mixing it with diatomite, and then drying and calcining it to obtain the diatomite.

6. The supported iron-ruthenium catalyst according to claim 5, characterized in that, The preparation method includes: spraying a quaternary ammonium salt solution onto diatomaceous earth, separating and screening it, drying it, calcining it, and adding a binder to form it. Preferably, the separation and screening is a cyclone separation; more preferably, the cyclone separation separates particles with a particle size of 6-12 μm, preferably 8-10 μm; Preferably, the calcination conditions include: calcination at 300℃-450℃ for 1-3 hours; Preferably, the solvent in the quaternary ammonium salt solution includes at least one of water and alcohols; Preferably, the adhesive is selected from at least one of montmorillonite, attapulgite, and methylcellulose.

7. A method for preparing a supported iron-ruthenium catalyst according to any one of claims 1-6, characterized in that, It is prepared by solution impregnation method, which involves mixing and impregnating a carrier with an aqueous solution containing iron salt, ruthenium salt and optional auxiliaries, and then calcining.

8. A method for preparing p-dichlorobenzene and / or m-dichlorobenzene, characterized in that, The supported iron-ruthenium catalyst prepared by any of the supported iron-ruthenium catalysts described in claims 1-6 or by the preparation method described in claim 7.

9. The preparation method according to claim 8, characterized in that, Includes the following steps: (1) Benzene reacts with chlorine gas to undergo chlorination; (2) After the reaction in step (1) is completed, the gas and liquid are separated. The liquid phase is stripped, crystallized and distilled to obtain m-dichlorobenzene and / or p-dichlorobenzene, respectively.

10. The preparation method according to claim 8 or 9, characterized in that, The conditions for the chlorination reaction in step (1) include: a molar ratio of benzene to chlorine of 2-3; a reaction temperature of 90-100℃; and a pressure of 0.1-0.4MPa.

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