KR20230024393A - Manufacturing method of copper-based hydrogenation catalyst, catalyst produced thereby and applications - Google Patents

Abstract

In this paper, a method for preparing a copper-based hydrogenation catalyst, a catalyst prepared thereby, and applications are disclosed, and activated carbon is sequentially impregnated in an acidic solution and an alkaline solution, followed by an ethanol-water mixture solution containing copper salt and lithium salt. is impregnated and aged, then dried and roasted to obtain a copper-based hydrogenation catalyst, which is composed of 3-10wt% copper oxide, 0.3-3wt% lithium oxide, and the remainder being activated carbon. The catalyst obtained by manufacturing has the advantages of excellent skeleton strength and pore size distribution, good mass transfer and heat transfer effect, high activity, high dispersity of active components, high ability to prevent sintering, and active components not easily lost. and can be used for industrial production of hydrogenation of acetophenone to produce α-phenethyl alcohol.

Description

Manufacturing method of copper-based hydrogenation catalyst, catalyst produced thereby and applications

This application belongs to the field of catalytic hydrogenation technology, and specifically relates to a catalyst for preparing α-phenethyl alcohol through liquid phase hydrogenation of acetophenone, a method for preparing the same, and an application thereof.

α-Phenethyl alcohol is an important chemical intermediate, widely used in medicine, perfume manufacturing, cosmetics, food and fine chemical industry and other industries. Existing methods for synthesizing α-phenethyl alcohol mainly include microbial fermentation and acetophenone reduction/catalytic hydrogenation.

Microbial fermentation methods generally use phenylalanine and fluorophenylalanine as raw materials and convert them through microbial fermentation to produce α-phenethyl alcohol. Raw materials used in microbial fermentation are too expensive, and production costs are too high. Currently, the production of α-phenethyl alcohol in industry generally uses the acetophenone hydrogenation method, which has advantages such as low production cost, small by-products, high product yield, and high product purity. , suitable for large-scale production of α-phenethyl alcohol.

Acetophenone hydrogenation catalysts mainly include platinum-palladium noble metal catalysts, nickel-based catalysts and copper-based catalysts, etc., noble metal catalysts and nickel-based catalysts are expensive, and easily cause saturation of the aromatic ring and hydrogenolysis of phenethyl alcohol, thereby The selectivity of α-phenethyl alcohol deteriorates. Compared with noble metal catalysts and nickel-based catalysts, copper-based hydrogenation catalysts used in acetophenone hydrogenation have advantages such as high activity and selectivity, and low cost, but have low catalyst strength, poor stability, and easy to obtain active ingredients. is lost, and hydrogenolysis/dehydration side reaction (α-phenethyl alcohol hydrogenolysis/dehydration side reaction occurs extremely easily in the process of acetophenone hydrogenation to produce ethylbenzene/styrene. The problem still exists, such as the rapid increase with

In CN1557545A, a Ni-Sn-B/SiO ₂ catalyst was prepared using an impregnation method, and after low-temperature roasting, it was reduced using KBH ₄ as a reducing agent. During the catalytic reaction, the highest selectivity of phenethyl alcohol reached 97.5%, The interaction force between the active component Ni and the carrier SiO ₂ is weak and is easily lost.

US4996374 discloses a Pd-C catalyst, but the stability of the catalyst is relatively poor, and when used as it is, the reaction temperature must be constantly raised.

CN1315226A discloses a reduced copper-based catalyst and a method for producing α-phenethyl alcohol using the same, but the process is complicated and expensive because a liquid-phase reduction method must be used to improve the stability of the catalyst. .

CN1911883A discloses a method for producing α-phenethyl alcohol using Raney Nickel as a catalyst, but since α-cyclohexyl ethanol, which is a relatively large amount of aromatic ring hydrogenation product, is shown in the acetophenone hydrogenation product, α-phenol The selectivity of ethyl alcohol is relatively low.

Therefore, by solving problems such as low binding force between the catalytically active component and the carrier, inactivation of the catalyst due to loss of the active component, and non-uniform dispersion of the active component, which exist in the existing technology, copper-based hydrogenation catalysts By improving the low-temperature activity, improving the dispersibility of copper in the catalyst, reducing the loss of active components, improving the strength of the catalyst, and suppressing the formation of by-products, to prepare a high activity, high selectivity acetophenone hydrogenation catalyst Doing has great meaning.

The following is an overview of the topics detailed in this document. This summary is not intended to limit the scope of protection of the claims.

An object of the present application is to provide a method for preparing a copper-based catalyst for preparing α-phenethyl alcohol by liquid-phase hydrogenation of acetophenone and a catalyst obtained by the preparation in order to solve the above problems existing in the existing technology.

The copper-based catalyst of the present application uses activated carbon as a carrier and metal lithium as an adjuvant, and is prepared through an ion exchange method. The catalyst obtained by manufacturing has the advantages of excellent skeleton strength and pore size distribution, good mass transfer and heat transfer effect, high activity, high dispersity of active components, high ability to prevent sintering, and active components not easily lost. provide more

When the catalyst according to the present application is applied to the liquid phase hydrogenation of acetophenone to produce α-phenethyl alcohol, the catalyst further has excellent low-temperature activity, thereby effectively reducing the production of by-products, especially In the auxiliary lithium element, by using Cu-Li in combination, the alkalinity of the catalyst can be improved, the hydrogenolysis/dehydration side reaction can be effectively suppressed, and further advantages such as long cycle stability are provided.

In order to implement one aspect of the above object, the present application uses the following technical measures.

The method for preparing a copper-based hydrogenation catalyst includes the following steps.

(1) After the activated carbon is impregnated with an acidic solution, it is separated and washed;

(2) the activated carbon treated in step (1) is immersed in an alkaline solution, then separated, washed and dried;

(3) The activated carbon treated in step (2) is added to an ethanol-water mixture containing a copper salt and a lithium salt, subjected to impregnation aging, and then separated, washed, dried, and roasted to obtain a copper-based hydrogenation catalyst.

In the production method step (1) of the present application, the acid solution is an aqueous acid solution, and the concentration is 0.5-2 mol/L, preferably 0.8-1.5 mol/L; The acid is selected from one or more of nitric acid, hydrochloric acid or sulfuric acid, and is preferably nitric acid. When the acid concentration is relatively low, on the one hand, it directly affects the number of groups on the surface of the carrier; Foreign matter remains, affecting the activity and selectivity of the catalyst, on the other hand, when the acid concentration is relatively high, the carrier is damaged, affecting the service life of the carrier.

In step (1) of the manufacturing method of the present application, the activated carbon is any one of coconut shell charcoal and wood-based carbon, and its iodine value is 600-1500, preferably 800-1300; The particle size is 4-60 mesh, preferably 8-16 mesh. The iodine value of activated carbon was studied experimentally. A reasonable iodine value range in the present application is advantageous for promoting the progress of the hydrogenation reaction, but on the other hand, it is disadvantageous for the reaction performance and physical performance of the catalyst.

In step (1) of the production method of the present application, the condition of the impregnation treatment is normal pressure excessive impregnation, and the impregnation temperature is 80-140°C, preferably 90-130°C; The time is 2-8h, preferably 3-6h. In the impregnation treatment process, in this step, the amount of acidic solution used is not specifically limited, as long as the activated carbon carrier can be completely impregnated. Since the impregnation temperature mainly has an accelerating effect on the formation of organic functional groups on the surface of the carrier, both too low and too high temperatures are disadvantageous.

In step (1) of the manufacturing method of the present application, the separation and washing following the impregnation treatment use a conventional operating method and are not specifically required. In one embodiment, the separation may use a centrifugal separation method, and the washing may use a water washing method. By impregnating the activated carbon carrier with an acidic solution in step (1), on the one hand, foreign substances on the activated carbon can be removed, and on the other hand, for modifying oxygen-containing functional groups on the surface of the activated carbon, activated carbon itself is an inert material , Since there are few functional groups on the surface, after high-temperature oxidation treatment in an acidic solution, oxygen-containing groups such as -COOH functional groups increase on the surface of activated carbon, and it is prepared for the next stage of modification after modification.

In step (2) of the production method of the present application, the alkaline solution is an alkaline aqueous solution containing an ammonium salt, and the concentration is 2-10wt%, preferably 3-8wt%; The ammonium salt is selected from ammonium carbonate and/or ammonium hydrogen carbonate.

In step (2) of the manufacturing method of the present application, the condition of the impregnation treatment is atmospheric pressure excess water impregnation, and the temperature is 20-60°C, preferably 30-50°C; The soaking time is 2-8h, preferably 3-6h. In the impregnation treatment process, in this step, there is no specific limitation on the amount of alkaline solution used, as long as the activated carbon carrier can be completely impregnated, but in order to sufficiently exchange the functional groups generated in the carrier after acid treatment in step (1) It should be ensured that the solution is provided with sufficient ?t of ionic water. In step (2), an ammonium salt is used to modify the activated carbon surface, NH ⁴⁺ ions are used to replace the oxygen-containing functional group modified in the first step, for example, -COOH to -COONH ₄ The purpose of reforming is to prepare for copper ion exchange in the next step, otherwise the copper ion exchange reaction is disadvantageous.

In step (2) of the production method of the present application, the drying temperature is 90-150°C, preferably 100-130°C; the time is 2-8h, preferably 3-6h; Separation and washing in this step use a regular operation method, and there is no specific requirement. In some examples, the separation may use a centrifugal separation method, and the washing may use water washing.

In step (3) of the manufacturing method of the present application, in the ethanol-water mixed solution containing the copper salt and the lithium salt, the concentration of the copper salt is 10-45 wt%, based on the total weight of the mixed solution, preferably 15-30wt%; The lithium salt concentration is 10-40wt%, preferably 20-30wt%; Ethanol concentration is 2-8wt%, preferably 3-6wt%;

Preferably, the copper salt is one or more of copper nitrate, copper chloride or copper acetate;

Preferably, the lithium salt is one or more of lithium nitrate or lithium chloride.

In step (3) of the manufacturing method of the present application, the impregnation aging process is preferably isovolumetric impregnation aging under normal pressure conditions, and the temperature is 20-60°C, preferably 30-50°C; The time is 2-8h, preferably 3-6h.

In step (3) of the production method of the present application, the drying temperature is 90-150°C, preferably 100-130°C; the time is 2-8h, preferably 3-6h;

The roasting temperature is 300-600°C, preferably 400-500°C; The time is 2-8h, preferably 3-6h.

In this step, the separation and washing use a regular operation method, and there is no specific requirement. In some examples, the separation may use a filtration method, and the washing may use water washing.

The production method of the present application controls the pretreatment step for the carrier, combines ion exchange methods, and loads the active ingredients using chemical bonds, so the ingredients are not easily lost. As a result, the prepared catalyst has a stronger binding force between the active component and the carrier and more excellent stability compared to the conventional impregnation method.

In the present application, in the copper-based hydrogenation catalyst prepared and obtained by the above method, based on the total weight of the catalyst, the catalyst contains 3-10 wt% of copper oxide, preferably 5-8 wt%, 0.3-3 wt% of lithium oxide, It is preferably composed of 0.5-2wt%, the balance being activated carbon, thereby obtaining a supported hydrogenation catalyst, and the active component exhibits an eggshell type distribution.

In another aspect, the present application further provides the application of the copper-based hydrogenation catalyst in preparing α-phenethyl alcohol through liquid phase hydrogenation of acetophenone.

A method for producing α-phenethyl alcohol through acetophenone hydrogenation is obtained by producing α-phenethyl alcohol by acetophenone hydrogenation under the above copper-based hydrogenation catalyst action conditions.

Preferably, the hydrogenation reaction conditions are as follows. The reaction pressure is 2-5 MPa (gauge pressure), preferably 2.5-4 MPa (gauge pressure), the reaction temperature is 60-100 °C, preferably 70-90 °C, and the H ₂ /HPA (acetophenone) molar ratio is It is 2-20:1, preferably 5-15:1, and the amount of catalyst used is 0.2-0.6 gHPA·gcat ^-1 ·h ^-1 , preferably 0.3-0.5 gHPA·gcat ^-1 ·h ^-1 .

Preferably, the hydrogenation raw material further includes a solvent, the solvent is ethylbenzene, and the concentration of acetophenone in the solvent is 10-15wt%.

It should be understood by those skilled in the art that the catalyst can have a corresponding catalytic activity only after undergoing reduction activation, and preferably, the copper-based hydrogenation catalyst in a reduced state is converted to acetophenone hydrogenation to produce α-phenethyl alcohol. use for

Reductive activation of the hydrogenation catalyst is a routine operation in the art. In a preferred embodiment, the reduction activation method of the catalyst according to the present application includes: maintaining the mixed gas volume space velocity of hydrogen gas and nitrogen gas at 300-1000h ^-1 ; , Preferably first, the reactor temperature is raised to 160-180 ° C., and the physical water adsorbed on the catalyst is removed at a constant temperature for 1-2 h, and then the volume fraction of H ₂ not exceeding 10v% is contained. For example, by injecting a mixed gas of hydrogen gas and nitrogen gas containing (5v% ± 2v%) H ₂ , the catalyst is pre-reduced for at least 0.5 h, for example, for 1 h, 1.5 h or 2 h. After pre-reduction, the hydrogen gas ratio in the mixed gas of hydrogen gas and nitrogen gas is gradually increased, for example, gradually increased to 10v%, 20v%, 50v%, or 100%, and in the process, the catalyst layer hot spot temperature is increased. It is controlled not to exceed 220°C, and finally heated to 200-220°C and reduced in a pure hydrogen gas atmosphere for 2-5h, for example 3h or 4h, to obtain an activated catalyst.

Compared to the existing technology, the beneficial effects of the technical solution of the present application are as follows.

In this application, the catalyst obtained by using activated carbon as a catalyst carrier, utilizing the synergistic effect of copper-lithium two metals, and also using the ion exchange method, improves the degree of dispersion of active components, and has high catalytic activity. , It has good low-temperature activity compared to conventional copper-based catalysts, and active components are not easily lost, which not only improves the long cycle stability of the catalyst, but also improves the ability of the catalyst to prevent sintering. In addition, the catalyst is coconut shell charcoal Since the use of such a carrier provides excellent skeleton strength and pore size distribution, it is advantageous for the diffusion effect of the reactant material and has good mass transfer and heat transfer effects. Since the catalyst is used for hydrogenation of acetophenone to produce α-phenethyl alcohol, it can effectively improve the hydrogenation ability of the catalyst and suppresses side reactions such as dehydration of phenethyl alcohol, so it has advantages such as high activity and high selectivity. to provide

Other aspects may become apparent when the detailed description is read and understood.

Below, the method of the present application is described in detail by combining examples, but is not limited to the examples.

1. Origin of main raw materials in Examples and Comparative Examples:

Coconut shell charcoal: particle size 8-16 mesh, iodine value 800-1300, pore volume 0.38 cm ³ /g, purchased from Mls Co., Ltd.

Aluminum oxide carrier: particle size 8-30 mesh, specific surface area 274 m ² /g, pore volume 0.86 cm ³ /g, purchased from SHANDONG ALUMINIUM INDUSTRY CO., LTD.

Unless otherwise specified, all other raw materials are generally commercially available products, and all reagents are reagents for analysis.

2. Product Analysis Methods of Examples and Comparative Examples:

The element content in the catalyst is measured using an X-ray Fluorescence Spectrometer (XRF).

Copper ions in the hydrogenation solution are measured using inductively coupled plasma emission spectrometry (ICP) mass spectrometry.

The transverse compressive strength of the catalyst was tested using a type D-III strength tester, 50 samples were tested, and the average value was taken.

The number of moles of acetophenone contained in the raw material, the number of moles of phenethyl alcohol produced, and the number of moles of ethylbenzene and styrene produced by side reactions were analyzed using an Agilent 7820A gas chromatography and then calculated and tested. The conditions include: DB-5 chromatography column, FID detector is used, the vaporization chamber temperature is 260°C, the detector temperature is 260°C, and the carrier gas is high purity N ₂ with a flow rate of 30 ml/min.

Acetophenone conversion rate = (1- number of moles of acetophenone remaining in the reaction solution/number of moles of acetophenone contained in the raw material) * 100%;

phenethyl alcohol selectivity=number of moles of phenethyl alcohol produced/number of moles of acetophenone already converted*100%;

The calculation methods for ethylbenzene selectivity and styrene selectivity are the same as those for phenethyl alcohol.

Example 1

Preparation of copper-based hydrogenation catalyst:

(1) 50 ml of an aqueous nitric acid solution having a concentration of 1 mol/L is prepared by blending, 15 g of activated carbon is added to the aqueous nitric acid solution, heated to 90° C., immersed in excess water at a constant temperature for 4 h, followed by centrifugation and water washing. .

(2) 50 g of an aqueous solution of ammonium carbonate having a concentration of 5 wt% was blended, and the activated carbon treated in step (1) was added to the aqueous solution of ammonium carbonate, impregnated with excess water at room temperature at 25° C. for 4 h, centrifuged, and washed with water. and dried at 100° C. for 4 h.

(3) 9.13 g of an ethanol-water mixed solution of copper nitrate and lithium nitrate was blended and prepared, based on the total weight of the mixed solution, of which copper nitrate was 11.6 wt%, lithium nitrate was 22.7 wt%, and ethanol was 5wt%; Then, activated carbon subjected to step (2) treatment was added, followed by isolytic impregnation aging at room temperature of 25 ° C for 4 h, drying at 100 ° C for 4 h, and roasting at 400 ° C for 4 h, so that the copper oxide content was 3 wt%, A catalyst A having a lithium oxide content of 3 wt% is obtained.

Example 2

Preparation of copper-based hydrogenation catalyst:

(1) 50 ml of an aqueous hydrochloric acid solution having a concentration of 1.5 mol/L was prepared by blending, 15 g of activated carbon was added to the aqueous hydrochloric acid solution, heated to 90° C., impregnated with excess water at a constant temperature for 4 h, followed by centrifugation and water washing. do.

(2) 50 g of an aqueous solution of ammonium bicarbonate having a concentration of 8 wt% is blended, and the activated carbon treated in step (1) is added to the aqueous solution of ammonium bicarbonate, impregnated with excess water at room temperature at 25° C. for 4 h, centrifuged, and Proceed with washing and drying at 90° C. for 5 h.

(3) 7.4 g of an ethanol-water mixed solution of copper nitrate and lithium nitrate was blended and prepared, based on the total weight of the mixed solution, of which copper nitrate was 14.3 wt%, lithium nitrate was 4.7 wt%, and ethanol was 5wt%; Then, activated carbon subjected to step (2) treatment was added, followed by isolytic impregnation aging at room temperature of 25 ° C for 4 h, drying at 100 ° C for 4 h, and roasting at 450 ° C for 4 h, so that the copper oxide content was 3 wt%, A catalyst B having a lithium oxide content of 0.5 wt% is obtained.

Example 3

Preparation of copper-based hydrogenation catalyst:

(1) 50 ml of aqueous sulfuric acid solution having a concentration of 0.5 mol/L is prepared by blending, 15 g of activated carbon is added to the aqueous sulfuric acid solution, heated to 90° C., impregnated with excess water at a constant temperature for 4 h, followed by centrifugation and washing .

(2) 50 g of an aqueous solution of ammonium carbonate having a concentration of 5 wt% was blended, and the activated carbon treated in step (1) was added to the ammonium carbonate solution, impregnated with excess water at room temperature of 45° C. for 4 h, centrifuged, and washed with water. and dried at 90° C. for 5 h.

(3) 10.6 g of an ethanol-water mixed solution of copper nitrate and lithium nitrate was blended and prepared, based on the total weight of the mixed solution, of which copper nitrate was 33.4 wt%, lithium nitrate was 9.8 wt%, and ethanol was 5wt%; Then, activated carbon subjected to step (2) treatment was added, followed by isolytic impregnation and aging at 30° C. room temperature for 4 h, drying at 100° C. for 4 h, and roasting at 400° C. for 4 h. Catalyst C having a lithium content of 1.5 wt% is obtained.

Example 4

Preparation of copper-based hydrogenation catalyst:

(1) 50 ml of a nitric acid aqueous solution having a concentration of 2 mol/L is blended, 15 g of activated carbon is added to the nitric acid aqueous solution, heated to 80° C., immersed in excess water at a constant temperature for 4 h, followed by centrifugation and washing.

(2) 50 g of an aqueous solution of ammonium carbonate having a concentration of 10 wt % was blended, and the activated carbon treated in step (1) was added to the ammonium carbonate solution, impregnated with excess water at room temperature at 20° C. for 4 h, centrifuged, and washed with water. and dried at 90° C. for 5 h.

(3) 10.6 g of an ethanol-water mixed solution of copper nitrate and lithium nitrate was blended and prepared, based on the total weight of the mixed solution, of which copper nitrate was 33.4 wt%, lithium nitrate was 9.8 wt%, and ethanol was 5wt%; Then, activated carbon subjected to step (2) treatment was added, followed by isolytic impregnation and aging at 30° C. room temperature for 4 h, drying at 100° C. for 4 h, and roasting at 400° C. for 4 h. Catalyst D having a lithium content of 1.5 wt % is obtained.

Example 5

Preparation of copper-based hydrogenation catalyst:

(1) 50 ml of a nitric acid aqueous solution having a concentration of 2 mol/L is blended, 15 g of activated carbon is added to the nitric acid aqueous solution, heated to 80° C., immersed in excess water at a constant temperature for 4 h, followed by centrifugation and washing.

(2) 50 g of an aqueous solution of ammonium carbonate having a concentration of 10 wt% was mixed and prepared, the activated carbon treated in step (1) was added to the ammonium carbonate solution, impregnated with excess water at room temperature at 20 ° C for 4 h, centrifuged and washed with water and dried at 90° C. for 5 h.

(3) 9.1 g of an ethanol-water mixed solution of copper nitrate and lithium nitrate was blended and prepared, based on the total weight of the mixed solution, of which copper nitrate was 31.3 wt%, lithium nitrate was 2.3 wt%, and ethanol was 2wt%; Then, activated carbon subjected to step (2) treatment was added, followed by isolytic impregnation and aging at 30° C. Catalyst E having a lithium content of 0.3 wt% is obtained.

Comparative Example 1

Referring to the production method of Example 1, the only difference is that catalyst F having a copper content of 3 wt% and a lithium oxide content of 3 wt% is obtained without undergoing the alkaline solution impregnation treatment in step (2).

Comparative Example 2

Referring to the production method of Example 2, the only difference is that catalyst G having a copper oxide content of 3 wt% and a lithium oxide content of 0.5 wt% is obtained without undergoing the acidic solution impregnation treatment in step (1).

Comparative Example 3

Referring to the production method of Example 1, the only difference is that in step (3), lithium nitrate is not added, and catalyst H having a copper oxide content of 3 wt% is obtained.

Comparative Example 4

Referring to the production method of Example 2, the only difference is that lithium nitrate is replaced with 0.43 g of sodium nitrate in step (3) to obtain catalyst I having a copper oxide content of 3 wt% and a sodium oxide content of 0.5 wt%. will be.

Comparative Example 5

Referring to the preparation method of Example 2, the only difference is that in step (3), the activated carbon is replaced with the same mass of aluminum oxide to obtain a catalyst J with a copper oxide content of 3wt% and a lithium oxide content of 0.5wt%. .

Comparative Example 6

Referring to the production method of Example 1, the only difference is that the order of step (1) and step (2) is exchanged. An acidic solution impregnation treatment is performed to obtain a catalyst K having a copper oxide content of 3 wt% and a lithium oxide content of 0.5 wt%.

Comparative Example 7

8.07 g of an ethanol-water mixed solution of copper nitrate and lithium nitrate was blended and prepared, based on the total weight of the mixed solution, of which copper nitrate was 13.4 wt%, lithium nitrate was 25.7 wt%, and ethanol was 3.7 wt%. ego; Untreated activated carbon was added to the solution, followed by isolytic impregnation aging at 25° C. room temperature for 4 h, followed by drying at 100° C. for 4 h and roasting at 400° C. for 4 h, so that the copper oxide content was 3 wt% and the lithium oxide content was A 3 wt% catalyst L is obtained.

Catalyst Application Examples

The copper-based hydrogenation catalysts prepared in Examples 1-5 and Comparative Examples 1-7 were used in the acetophenone hydrogenation reaction to produce α-phenethyl alcohol, and the steps are as follows.

Catalyst reduction: The catalyst is put into the fixed bed hydrogenation reactor, and the filling amount of the catalyst is 20ml. The catalyst is reduced under a mixed gas condition of nitrogen gas and hydrogen gas before use. In the reduction process, the volumetric space velocity of the mixed gas is maintained at 300h ^-1 , the reactor temperature is first raised to 160°C, and the catalyst is kept at a constant temperature for 2h. After removing the physical water adsorbed on it, a mixture of hydrogen gas and nitrogen gas containing H ₂ with a volume fraction of 5v% was injected to pre-reduce for 1 hour, and then the hydrogen gas in the mixture gas of hydrogen gas and nitrogen gas was reduced. The ratio is gradually raised to 10v%, 20v%, 50v%, and 100%, and in the process, the catalyst layer hot spot temperature is controlled so that it does not exceed 220 ° C, and finally the temperature is raised to 220 ° C and reduced for 3 h in a pure hydrogen gas atmosphere. let it

The hydrogenation raw material is composed of an ethylbenzene solution of 15 wt% acetophenone, and the pressure is 2.5 MPa (gauge pressure), the temperature is 70 ° C, the H ₂ /HPA molar ratio is 5: 1, and the catalyst throughput is 0.3 gHPA / gcat / h. The reaction proceeds in

The hydrogenation solution is taken every 24 h, and the content of copper ions in the hydrogenation solution is measured. After the reaction proceeds for 1000 h, the catalyst is separated from the reactor, the catalyst is sieved with a stainless steel sample separation screen with a pore size of 2 mm, and the proportion of the mass of catalyst particles with a particle size of <1 mm to the total mass of the catalyst is calculated, which is It is set as the catalyst breakage rate.

See Table 1 for catalyst performance, hydrogenation reaction results, and average copper ion content in the hydrogenation solution.

Table 1

As can be seen from Table 1, when Catalysts A to E, Catalyst H, Catalyst I and Catalyst J were used, copper was not detected in the hydrogenation solution, and Catalyst F, Catalyst G, Catalyst K and Catalyst L were analyzed by ICP. The copper content in the hydrogenation solution is relatively high, as shown through , which explains the clear loss of the catalyst. In addition, catalysts A to E have high activity and can effectively suppress side reactions such as generation of ethylbenzene by hydrocracking and generation of styrene by dehydration, whereas the catalysts according to Comparative Examples 1 to 7 have high activity. low. Further, after a long cycle stable run for 1000 h, the acetophenone conversion rate of catalysts A to E is greater than 99%, and the selectivity of α-phenethyl alcohol is greater than 99%.

Example 6

The copper-based hydrogenation catalyst B prepared in Example 2 was used in the hydrogenation reaction of acetophenone to produce α-phenethyl alcohol, and the reaction temperature was adjusted based on the method of Example 4. The hydrogenation reaction results are shown in Table 2. Same as

Table 2

As can be seen from Table 2, at the hydrogenation reaction temperature of 60-100 ° C., all relatively high conversion rates of acetophenone can be obtained, and the conversion rate of acetophenone increases with increasing temperature, but the selectivity of α-phenethyl alcohol As it decreases, 70-80 DEG C is the most excellent condition, and the selectivity of α-phenethyl alcohol is all 99% or more, which explains that the catalyst has very good low-temperature activity.

Claims (12)

(1) impregnating activated carbon with an acidic solution, separating and washing;
(2) immersing the activated carbon treated in step (1) in an alkaline solution, followed by separation, washing and drying;
(3) Adding the activated carbon treated in step (2) to an ethanol-water mixture solution containing copper salt and lithium salt, subjecting it to impregnation aging, followed by separation, washing, drying, and roasting to obtain a copper-based hydrogenation catalyst. ; Method for producing a copper-based hydrogenation catalyst comprising a. According to claim 1,
In step (1), the acidic solution is an aqueous solution of acid, and the concentration is 0.5-2 mol/L, preferably 0.8-1.5 mol/L; The acid is selected from one or more of nitric acid, hydrochloric acid or sulfuric acid, preferably nitric acid;
The activated carbon is any one of coconut shell charcoal or wood-based carbon, and its iodine value is 600-1500, preferably 800-1300; Method for producing a copper-based hydrogenation catalyst having a particle size of 4-60 mesh, preferably 8-16 mesh. According to claim 1 or 2,
In step (1), the impregnation temperature of the impregnation treatment is 80-140°C, preferably 90-130°C; Method for producing a copper-based hydrogenation catalyst in which the time is 2-8 h, preferably 3-6 h. According to any one of claims 1 to 3,
In step (2), the alkaline solution is an alkaline aqueous solution containing an ammonium salt, and the concentration is 2-10wt%, preferably 3-8wt%; The ammonium salt is a method for producing a copper-based hydrogenation catalyst selected from ammonium carbonate and / or ammonium hydrogen carbonate. According to any one of claims 1 to 4,
In step (2), the impregnation temperature of the impregnation treatment is 20-60°C, preferably 30-50°C; The impregnation time is 2-8h, preferably 3-6h, a method for producing a copper-based hydrogenation catalyst. According to any one of claims 1 to 5,
In step (3), in the ethanol-water mixed solution containing the copper salt and the lithium salt, the copper salt concentration is 10-45 wt%, preferably 15-30 wt%, based on the total weight of the mixed solution. ; The lithium salt concentration is 10-40wt%, preferably 20-30wt%; Ethanol concentration is 2-8wt%, preferably 3-6wt%;
Preferably, the copper salt is one or more of copper nitrate, copper chloride or copper acetate;
Preferably, the lithium salt is one or more of lithium nitrate or lithium chloride. Method for producing a copper-based hydrogenation catalyst. According to any one of claims 1 to 6,
In step (3), in the process of immersion aging, the temperature is 20-60°C, preferably 30-50°C; the time is 2-8h, preferably 3-6h;
The drying temperature is 90-150°C, preferably 100-130°C; the time is 2-8h, preferably 3-6h;
The roasting temperature is 300-600°C, preferably 400-500°C; Method for producing a copper-based hydrogenation catalyst in which the time is 2-8 h, preferably 3-6 h. Based on the total weight of the catalyst, the catalyst is a copper-based hydrogenation catalyst according to any one of claims 1 to 7, comprising 3-10wt% of copper oxide, 0.3-3wt% of lithium oxide, and the balance being activated carbon. A copper-based hydrogenation catalyst prepared by the production method of. According to claim 8,
Based on the total weight of the catalyst, copper oxide in the catalyst is 5-8wt%;
Preferably, based on the total weight of the catalyst, lithium oxide in the total mass is 0.5-2wt%. A copper-based hydrogenation catalyst prepared by the method for preparing a copper-based hydrogenation catalyst according to any one of claims 1 to 7 in liquid phase hydrogenation of acetophenone for producing α-phenethyl alcohol, or claim 8 or 8 Application of the copper-based hydrogenation catalyst according to claim 9. Under the operating conditions of the copper-based hydrogenation catalyst prepared by the method for preparing a copper-based hydrogenation catalyst according to any one of claims 1 to 7, or the copper-based hydrogenation catalyst according to claim 8 or 9, acetophenone obtained by producing α-phenethyl alcohol by hydrogenation;
The hydrogenation reaction conditions are: the reaction pressure is 2-5 MPa (gauge pressure), the reaction temperature is 60-100 °C, the H ₂ /HPA molar ratio is 2-20:1, and the amount of catalyst used is 0.2-0.6 gHPA·gcat A method for producing α-phenethyl alcohol through hydrogenation of acetophenone with ⁻¹ ·h ⁻¹ . According to claim 11,
The reaction pressure is 2.5-4 MPa (gauge pressure);
Preferably, the reaction temperature is 70-90°C;
Preferably, the H ₂ /HPA molar ratio is 5-15:1;
Preferably, the amount of catalyst used is 0.3-0.5 gHPA·gcat ^-1 ·h ^-1 ;
Preferably, the hydrogenation raw material further comprises a solvent, the solvent is ethylbenzene, and the concentration of acetophenone in the solvent is 10-15wt%. A method for producing α-phenethyl alcohol through hydrogenation of acetophenone.