Catalyst for chlorobenzene purification and preparation method thereof

Abstract

The invention relates to the technical field of catalysts, in particular to a catalyst for chlorobenzene purification and a preparation method thereof. The preparation method of the catalyst comprises the following steps: dissolving copper salt and cerium salt in water to obtain a solution A; adding an oxalic acid solution into the solution A and stirring to obtain a turbid liquid; and centrifugally separating the suspension, centrifugally washing the obtained solid until the solid is neutral, drying and calcining to obtain the catalyst. According to the invention, a reverse load dispersion process is utilized, and a traditional carrier is controllably deposited on an active component, so that the reverse load dispersion type catalyst with high activity and low energy consumption is prepared. The catalyst provided by the invention is used for low-temperature stable catalytic oxidation of chlorobenzene, shows excellent chlorine resistance, can greatly reduce the operation cost of enterprises, and effectively reduces the economic cost of commercial catalysts.

Description

Technical Field

[0001] This invention relates to the field of catalyst technology, and in particular to a catalyst for the purification of chlorobenzene and its preparation method. Background Technology

[0002] Among various volatile organic compounds (VOCs), chlorinated volatile organic compounds (Cl-VOCs) have received widespread attention worldwide due to their high environmental toxicity and persistent hazards. Cl-VOCs cannot be effectively degraded naturally, and most of those released into the environment accumulate. Chlorobenzene (CB) is a typical Cl-VOC commonly found in solid waste treatment, pharmaceuticals, and the chemical industry. Once released into the atmosphere, CB forms ozone, photochemical smog, and secondary organic aerosols, exhibiting high toxicity. Therefore, controlling CB pollution is crucial for reducing environmental risks. Summary of the Invention

[0003] Based on the above, this invention provides a catalyst for chlorobenzene purification and its preparation method. The catalyst for chlorobenzene purification is prepared by a reverse-supported dispersion process. The catalyst prepared by this method exhibits low-temperature purification performance for chlorobenzene (T90 = 290℃).

[0004] To achieve the above objectives, the present invention provides the following solution: One of the technical solutions of the present invention is a method for preparing a catalyst, comprising the following steps: Copper salt and cerium salt are dissolved in water to obtain solution A; Oxalic acid solution was added to solution A and stirred to obtain a suspension; the suspension was centrifuged, and the resulting solid was washed by centrifugation until neutral, dried, and calcined to obtain the catalyst (reverse supported dispersion catalyst).

[0005] The second technical solution of the present invention is a catalyst prepared according to the above preparation method.

[0006] The third technical solution of the present invention is the application of the above-mentioned catalyst in the catalytic oxidation of chlorobenzene.

[0007] Compared with the prior art, the present invention has the following beneficial effects: This invention utilizes a reverse-supported dispersion process to controllably deposit a conventional support onto an active component, preparing a highly active, low-energy-consumption reverse-supported dispersion catalyst. Using the active component as a support, this invention deposits a conventional support onto the active component, preparing a reverse-supported dispersion catalyst using a simple process for the low-temperature stable catalytic oxidation of chlorobenzene. This catalyst exhibits high activity at 30000 mL·g -1 ·h -1At a space velocity of 500 ppm chlorobenzene, a 90% conversion rate is achieved at 290℃ and a 50% conversion rate at 230℃, demonstrating excellent chlorine resistance. This can significantly reduce enterprise operating costs and effectively reduce the economic cost of commercial catalysts. Attached Figure Description

[0008] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0009] Figure 1 The XRD patterns are those of the catalysts prepared in Examples 1, 1, 2, and 3 of this invention.

[0010] Figure 2 The conversion rates of chlorobenzene (CB) catalytic oxidation by the catalysts prepared in Examples 1, 1, 2, and 3 of this invention at different temperatures are shown.

[0011] Figure 3 The stability curves are for the catalysts prepared in Examples 1, 1, 2, and 3 of this invention. Detailed Implementation

[0012] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0013] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0014] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0015] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0016] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0017] The first aspect of this invention provides a method for preparing a catalyst, comprising the following steps: Copper salt and cerium salt are dissolved in water to obtain solution A; Oxalic acid solution was added to solution A and stirred to obtain a suspension; the suspension was centrifuged, and the resulting solid was washed by centrifugation until neutral, dried, and calcined to obtain the catalyst.

[0018] In a preferred embodiment of the present invention, the copper salt is copper sulfate; the cerium salt is cerium nitrate.

[0019] In a preferred embodiment of the present invention, the concentration of copper salt in solution A is 21-30 mg / ml, and the concentration of cerium salt is 10-25 mg / ml.

[0020] In a preferred embodiment of the present invention, the solvent of the oxalic acid solution is ethanol; the concentration of oxalic acid in the oxalic acid solution is 55~70 mg / ml; and the volume ratio of solution A to the oxalic acid solution is 2:1.

[0021] In a preferred embodiment of the present invention, the stirring time is 20-40 minutes. The stirring speed has no particular effect on the performance of the catalyst; therefore, the present invention does not impose a particular limitation on the stirring speed and adopts a stirring speed commonly used by those skilled in the art.

[0022] In a preferred embodiment of the present invention, the drying temperature is 70~90℃ and the drying time is 7~9h.

[0023] In a preferred embodiment of the present invention, the calcination temperature is 300~600℃ and the calcination time is 2~5h.

[0024] In the catalyst preparation process, the present invention first adjusts the raw material ratio to generate a structure in which the active component is surrounded by the support, and then obtains a highly stable reverse-supported dispersion catalyst by repeatedly washing, drying and calcining.

[0025] A second aspect of the present invention provides a catalyst prepared according to the preparation method described above.

[0026] A third aspect of the present invention provides the application of the above-described catalyst in the catalytic oxidation of chlorobenzene.

[0027] This invention enables the controlled deposition of a conventional support onto the active component, resulting in a structure where the active component is surrounded by the support. A comparison of the VOCs purification performance of the obtained reverse-supported dispersed catalyst with that of a conventional supported catalyst (Comparative Example 3) shows that the prepared reverse-supported dispersed catalyst exhibits superior purification performance and stability. This invention features a simple preparation process and has high practical application value.

[0028] Unless otherwise specified, the technical solutions described in this invention are all conventional solutions in the field, and the reagents or raw materials used are all purchased from commercial channels or are publicly available unless otherwise specified.

[0029] The ethanol used in the embodiments of this invention is anhydrous ethanol.

[0030] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0031] Example 1 (1) Dissolve 2.4968g of copper sulfate pentahydrate and 1.7369g of cerium nitrate hexahydrate in 100ml of deionized water to obtain solution A; dissolve 3.1516g of oxalic acid in 50ml of ethanol to obtain solution B.

[0032] (2) Under stirring conditions, add solution B from (1) to solution A, mix, and continue stirring for 30 min. Centrifuge the resulting suspension. Wash the separated solid three times with deionized water until the washing liquid becomes neutral.

[0033] (3) The solid obtained in (2) was placed in an 80 °C oven and dried for 8 hours, and then placed in a muffle furnace and calcined at 500 °C for 4 hours to obtain the catalyst.

[0034] Comparative Example 1 (1) Dissolve 1.2484g of copper sulfate pentahydrate and 0.86845g of cerium nitrate hexahydrate in 100ml of deionized water to obtain solution A; dissolve 3.1516g of oxalic acid in 50ml of ethanol to obtain solution B.

[0035] (2) Under stirring conditions, add solution B from (1) to solution A, mix, and continue stirring for 30 min. Centrifuge the resulting suspension. Wash the separated solid three times with deionized water until the washing liquid becomes neutral.

[0036] (3) The solid obtained in (2) was placed in an 80 °C oven and dried for 8 hours, and then placed in a muffle furnace and calcined at 500 °C for 4 hours to obtain the catalyst.

[0037] Comparative Example 2 (1) Dissolve 3.7452g of copper sulfate pentahydrate and 2.60535g of cerium nitrate hexahydrate in 100ml of deionized water to obtain solution A; dissolve 3.1516g of oxalic acid in 50ml of ethanol to obtain solution B.

[0038] (2) Under stirring conditions, add solution B from (1) to solution A, mix, and continue stirring for 30 min. Centrifuge the resulting suspension. Wash the separated solid three times with deionized water until the washing liquid becomes neutral.

[0039] (3) The solid obtained in (2) was dried in an oven at 80 °C for 8 hours, and then calcined in a muffle furnace at 500 °C for 4 hours to obtain the catalyst.

[0040] Comparative Example 3 (1) Dissolve 2.4968g of copper sulfate pentahydrate and 1.7369g of cerium nitrate hexahydrate in 100ml of deionized water to obtain solution A.

[0041] (2) Place the solution obtained in (1) into an 80 ℃ oven and dry for 8 hours.

[0042] (3) The solid obtained in (2) was then placed in a muffle furnace and calcined at 500°C for 4 hours to obtain a catalyst.

[0043] Performance testing The catalytic oxidation activity of the catalysts prepared in Example 1 and Comparative Examples 1-2 was tested as follows: 0.1 g of catalyst (40-60 mesh) was placed in a fixed-bed reactor. Liquid chlorobenzene was bubbled into the reaction system using compressed air to simulate gas. The concentration of chlorobenzene was controlled at 500 ± 50 ppm by air, the total gas flow rate was 50 ml / min, and the gas space velocity was 30000 mL·g. -1 ·h -1 Real-time monitoring of chlorobenzene and CO2 concentrations via online chromatography: Figure 1 The XRD patterns of the catalysts prepared in Example 1 and Comparative Examples 1-3 of this invention are shown below. Figure 1 It can be seen that all samples contain characteristic peaks of CeO2 and CuO, indicating that the samples were successfully prepared.

[0044] Figure 2 The catalysts prepared in Examples 1 and Comparative Examples 1-3 of this invention were used to catalyze the conversion of chlorobenzene (CB) at different temperatures. Figure 2As can be seen, the catalyst prepared in Example 1 exhibits superior chlorobenzene oxidation ability compared to Comparative Examples 1, 2, and 3. It achieved a chlorobenzene conversion rate of 90% at 290°C and still maintained a 50% conversion rate at 230°C.

[0045] Figure 3 The stability curves are for the catalysts prepared in Example 1 and Comparative Examples 1-3 of this invention. Figure 3 As can be seen, the catalyst prepared in Example 1 exhibits excellent stability compared to Comparative Examples 1, 2, and 3 (which have a chlorobenzene conversion rate of 63% at 290°C and 25% at 230°C). Even after 160 hours of continuous operation, the chlorobenzene conversion rate still reaches 90%.

[0046] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for producing a catalyst, characterized by, The method comprises the following steps: dissolving copper salt and cerium salt in water to obtain solution A; adding oxalic acid solution into solution A to obtain suspension, centrifuging the suspension, drying and calcining the obtained solid to obtain the catalyst.

2. The production method according to claim 1, characterized by, The copper salt is copper sulfate, and the cerium salt is cerium nitrate.

3. The preparation method according to claim 1, characterized in that, The concentration of copper salt in solution A is 21-30 mg / ml, and the concentration of cerium salt is 10-25 mg / ml.

4. The production method according to claim 1, characterized by, The solvent of oxalic acid solution is ethanol, the concentration of oxalic acid in oxalic acid solution is 55-70 mg / ml, and the volume ratio of solution A to oxalic acid solution is 2:

1.

5. The preparation method according to claim 1, characterized in that, The stirring time is 20-40 min.

6. The method of claim 1, wherein, The drying temperature is 70-90 ℃, and the drying time is 7-9 h.

7. The preparation method according to claim 1, characterized in that, The calcining temperature is 300-600 ℃, and the calcining time is 2-5 h.

8. The catalyst prepared by the preparation method according to any one of claims 1-7.

9. The catalyst according to claim 8 in the application of catalyzing the oxidation of chlorobenzene.

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