A kind of preparation method of m-ethyl anisole

Abstract

The invention discloses a method for preparing m-ethyl anisole, wherein methanol and m-ethyl phenol are introduced into a catalyst loaded with Ti on a BiO2-CeO2 composite carrier, and m-ethyl anisole is prepared by reaction. The m-ethyl phenol has a high conversion rate, the m-ethyl anisole has a high selectivity, and can be continuously and stably operated for 3000 hours.

Description

Technical Field

[0001] The invention relates to the field of chemical synthesis, and in particular to a process for preparing m-ethyl anisole by reacting m-ethyl phenol with methanol. Background Art

[0002] Meta-ethylanisole, also known as 3-ethylanisole, is an important chemical intermediate that can be used to synthesize meta-methyl ether acetophenone, 2-ethyl-3-methoxyacetophenone, 2-ethyl-3-bromo-anisole and other substances. Currently, there is only one synthesis method, which is to react meta-ethylphenol with a methylating agent to produce meta-ethylanisole, and the methylating agent includes methyl iodide and dimethyl sulfate.

[0003] US 7,145,040 B2 patent proposes a preparation method, wherein m-ethylphenol (50 g, 0.4 mol, 98% purity), potassium carbonate (283 g, 2.05 mol) and acetone are mixed (500 mL), and then methyl iodide (290 g, 2.05 mol) is added. The mixture is placed in an autoclave and refluxed at 70°C overnight. After filtration through diatomaceous earth, washing with acetone, concentration, dissolution, filtration, and drying, the final yield is 90%. The article (J.Org.Chem., Vol.42, No.20,1977) mixed tetrabutylammonium hydroxide (10 mol%), sodium hydroxide (20 g, 0.5 mol), and 100 g of water into a slurry, and added meta-ethylphenol (30.5 g, 0.25 mol, 50 mL of aqueous solution) dropwise. After the reaction, 30 mL of dimethyl sulfate (0.3 mol) was added dropwise to the solution. After reacting for 2 hours, the oil layer was extracted with dichloromethane. The oil layer was separated at 70-71°C (9 Torr) to obtain 31.2 g (95%) of meta-ethylanisole, with a yield of 88.6%.

[0004] As can be seen from the above, the current synthesis method is extremely complicated, with a variety of raw materials and a lot of three wastes, making it difficult to achieve industrialization. In addition, methyl iodide has poor stability, is easily decomposed by light, and is very toxic, and is listed as a carcinogen. Dimethyl sulfate is also very toxic and has been used as a war gas. Sulfuric acid is generated during the reaction, and the equipment is highly corrosive. The existing methods all have the problems of complex processes, high costs and high toxicity, so it is imperative to find a green, clean and simple process. Contents of the invention

[0005] The object of the present invention is to provide a method for preparing m-ethyl anisole, wherein m-ethyl phenol and methanol are catalyzed to obtain m-ethyl anisole by using a novel catalyst. The reaction is simple and can be completed in one step. The raw material is only methanol, which is cheap and easy to obtain, and no other chemical substances are required. Water is generated by the reaction, and less three wastes are generated. The process adopts a continuous fixed bed process, has good reactivity and selectivity, and can achieve long-term stable operation.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] A method for producing m-ethyl anisole comprises the following steps: under the action of a catalyst, m-ethyl phenol and methanol are catalyzed to generate m-ethyl anisole, wherein the catalyst is a catalyst in which Ti is supported on a BiO2-CeO2 composite carrier.

[0008] In a preferred embodiment, the catalytic reaction of m-ethylphenol and methanol is carried out in a fixed bed; preferably, the amount of m-ethylphenol added is 20-70% of the total mass of m-ethylphenol and methanol.

[0009] In a preferred embodiment, the reaction temperature of m-ethylphenol and methanol is 230-270° C., and the reaction pressure is 0.1-0.3 bar(G).

[0010] In a preferred embodiment, the liquid hourly mass space velocity of m-ethylphenol is 0.1-1.2h -1 .

[0011] In a preferred embodiment, the method for preparing the catalyst supported by Ti on a BiO2-CeO2 composite carrier comprises the following steps:

[0012] (1) adding a certain amount of bismuth source into a mixed solution of pure water and ethanol;

[0013] (2) adding a certain amount of cerium source to the above solution and stirring until dissolved;

[0014] (3) adding a certain amount of dodecyldimethyl (3-sulfopropyl) ammonium hydroxide inner salt to the solution of step (2);

[0015] (4) adding a certain amount of ammonia water to the solution of step (3) until the pH reaches a certain value;

[0016] (5) filtering and washing the solution in step (4) until it becomes neutral, and roasting it in an air atmosphere for a period of time;

[0017] (6) dispersing a certain amount of titanium source in water;

[0018] (7) adding the sample obtained by calcining in step (5) to the solution in step (6), and heating under stirring until the water is evaporated;

[0019] (8) The sample evaporated in step (7) is calcined for a period of time under a nitrogen atmosphere to obtain a catalyst in which Ti is supported on a BiO2-CeO2 composite carrier.

[0020] Wherein, in step (1), the mass ratio of pure water to ethanol is 0.3-0.6.

[0021] In the step (1), the bismuth source accounts for 0.05-0.3 of the total mass of pure water and ethanol.

[0022] In the step (1), the bismuth source is one or more of bismuth acetate, bismuth nitrate pentahydrate and bismuth subnitrate.

[0023] Wherein, in the step (2), the cerium source is one or more of anhydrous cerium chloride, cerium (III) carbonate hydrate and cerium (III) acetate hydrate.

[0024] In the step (2), the amount of the cerium source added is 0.1-0.5 of the mass of the bismuth source;

[0025] Wherein, in the step (3), the amount of dodecyldimethyl (3-sulfopropyl) ammonium hydroxide inner salt added is 0.01-0.05 of the bismuth source.

[0026] Wherein, in the step (4), the pH value is controlled to be 5.6-8.3 after adding ammonia water.

[0027] Wherein, in the step (5), the calcination temperature is 300-500°C and the calcination time is 4-8h.

[0028] Wherein, in the step (6), the amount of titanium source added is 0.2-0.4 times the mass of water required for dispersion.

[0029] In the step (6), the titanium source is one or more of tetrabutyl titanate, titanium n-propoxide, and titanium tetraisopropoxide.

[0030] Wherein, in the step (7), the amount of titanium source added is 5-15% of the mass of the sample obtained by calcining in the step (5).

[0031] Wherein, in the step (8), the calcination temperature is 400-600°C and the calcination time is 5-10h.

[0032] After calcination, Bi, Ti and Ce interact strongly to form active centers of Bi-O-Ti and Ce-O-Ti, which work synergistically to catalyze the reaction. Bi-O-Ti has the function of adsorbing and activating methanol, while Ce-O-Ti protonates m-ethylphenol, and the protonated m-ethylphenol undergoes a dehydration reaction with methanol to generate m-ethylanisole.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1) The method of the present invention provides a novel synthesis process of m-ethyl anisole.

[0035] 2) The method of the present invention develops an efficient composite catalyst, uses a continuous fixed bed process, has high selectivity for meta-ethoxyanisole, and the yield of meta-ethylanisole can reach 97%. DETAILED DESCRIPTION

[0036] In order to better understand the technical solution of the present invention, the following examples will further illustrate the method provided by the present invention, but the present invention is not limited to the listed examples, and should also include any other known changes within the scope of the claims of the present invention.

[0037] The present invention is further described below with reference to the embodiments, but does not constitute any limitation.

[0038] Gas chromatography: The composition of the reaction solution was analyzed by gas chromatography. The operating conditions were: Shimadzu GC-2030 gas chromatograph, DB-5MS UI (20m×0.25mm×0.25μm) chromatographic column, acetonitrile as diluent. Vaporization chamber temperature 300°C, column flow 1.00mL / min, injection volume 0.2μL. Chromatographic column temperature program: first, the temperature was increased from 40°C to 100°C at a heating rate of 1.5°C / min, and finally the temperature was increased to 300°C at a heating rate of 10°C / min.

[0039] Reactor used in the embodiment: The reaction adopts a stainless steel fixed bed reactor, the inner diameter of the reaction tube is 20 mm, and 316L Theta rings are loaded at both ends of the catalyst.

[0040]

[0041]

[0042] Example 1

[0043] The preparation method of the catalyst is as follows:

[0044] (1) preparing a mixed solution with a mass ratio of pure water to ethanol of 0.4, adding a certain amount of bismuth acetate to the mixed solution of pure water and ethanol, wherein the amount of bismuth acetate added is 0.1 times the total mass of pure water and ethanol;

[0045] (2) adding a certain amount of anhydrous cerium chloride to the above solution and stirring evenly until dissolved, wherein the mass of anhydrous cerium chloride is 0.2 times the mass of bismuth acetate;

[0046] (3) adding a certain amount of dodecyldimethyl (3-sulfopropyl) ammonium hydroxide inner salt to the solution of step (2), the amount added being 0.03 times the mass of the bismuth source;

[0047] (4) adding a certain amount of aqueous ammonia to the solution of step (3) until the pH reaches 5.8;

[0048] (5) filtering and washing the solution in step (4) until it is neutral, and calcining at 400° C. for 6 h in an air atmosphere;

[0049] (6) dispersing a certain amount of titanium n-propoxide in water, wherein the amount of titanium n-propoxide added is 0.4 times the mass of water;

[0050] (7) adding the sample obtained by calcining in step (5) to the solution of step (6), heating under stirring until the water is completely evaporated, wherein the amount of titanium n-propoxide added is 13% of the mass of the sample obtained by calcining in step (5);

[0051] (8) The sample evaporated in step (7) was calcined at 450° C. for 6 h under a nitrogen atmosphere to obtain a catalyst in which Ti was supported on a BiO 2 -CeO 2 composite carrier.

[0052] The reaction conditions of m-ethylphenol and methanol are as follows:

[0053] The catalytic reaction of m-ethylphenol and methanol was carried out in a fixed bed. The amount of m-ethylphenol added was 33% of the total mass of m-ethylphenol and methanol. The reaction temperature was 238°C, the reaction pressure was 1.8 bar(G), and the liquid hourly mass space velocity of m-ethylphenol was 0.7 h -1 .

[0054] After the reaction is stable, samples are taken and the results are analyzed by gas chromatography. The specific results of the embodiment are shown in Table 1.

[0055] Example 2

[0056] The preparation method of the catalyst is as follows:

[0057] (1) preparing a mixed solution with a mass ratio of pure water to ethanol of 0.6, adding a certain amount of bismuth nitrate pentahydrate to the mixed solution of pure water and ethanol, wherein the amount of bismuth nitrate pentahydrate added is 0.25 times the total mass of pure water and ethanol;

[0058] (2) adding a certain amount of cerium (III) carbonate hydrate to the above solution and stirring evenly until dissolved, wherein the mass of cerium (III) carbonate hydrate is 0.5 times the mass of bismuth nitrate;

[0059] (3) adding a certain amount of dodecyldimethyl (3-sulfopropyl) ammonium hydroxide inner salt to the solution of step (2), the amount added being 0.04 times the mass of the bismuth source;

[0060] (4) adding a certain amount of ammonia water to the solution of step (3) until the pH reaches 7.2;

[0061] (5) filtering and washing the solution in step (4) until it is neutral, and calcining at 500° C. for 7 h in an air atmosphere;

[0062] (6) dispersing a certain amount of titanium tetraisopropoxide in water, wherein the amount of titanium tetraisopropoxide added is 0.3 times the mass of water;

[0063] (7) adding the sample obtained by calcining in step (5) to the solution of step (6), heating under stirring until the water is completely evaporated, wherein the amount of titanium tetraisopropoxide added is 6% of the mass of the sample obtained by calcining in step (5);

[0064] (8) The sample evaporated in step (7) was calcined at 550° C. for 8 h under a nitrogen atmosphere to obtain a catalyst in which Ti was supported on a BiO2-CeO2 composite carrier.

[0065] The reaction conditions of m-ethylphenol and methanol are as follows:

[0066] The catalytic reaction of m-ethylphenol and methanol was carried out in a fixed bed. The amount of m-ethylphenol added was 21% of the total mass of m-ethylphenol and methanol. The reaction temperature was 232°C, the reaction pressure was 2.4 bar(G), and the liquid hourly mass space velocity of m-ethylphenol was 1.0 h -1 .

[0067] After the reaction is stable, samples are taken and the results are analyzed by gas chromatography. The specific results of the embodiment are shown in Table 1.

[0068] Example 3

[0069] The preparation method of the catalyst is as follows:

[0070] (1) preparing a mixed solution with a mass ratio of pure water to ethanol of 0.3, adding a certain amount of bismuth subnitrate to the mixed solution of pure water and ethanol, wherein the amount of bismuth subnitrate added is 0.18 times the total mass of pure water and ethanol;

[0071] (2) adding a certain amount of cerium (III) acetate hydrate to the above solution and stirring evenly until dissolved, wherein the mass of cerium (III) acetate hydrate is 0.3 times the mass of bismuth subnitrate;

[0072] (3) adding a certain amount of dodecyldimethyl (3-sulfopropyl) ammonium hydroxide inner salt to the solution of step (2), the amount added being 0.02 times the mass of the bismuth source;

[0073] (4) adding a certain amount of ammonia water to the solution of step (3) until the pH reaches 8.1;

[0074] (5) filtering and washing the solution in step (4) until it is neutral, and calcining at 350° C. for 5 h in an air atmosphere;

[0075] (6) dispersing a certain amount of tetrabutyl titanate in water, wherein the amount of tetrabutyl titanate added is 0.4 times the mass of water;

[0076] (7) adding the sample obtained by calcining in step (5) to the solution of step (6), heating under stirring until the water is completely evaporated, wherein the amount of tetrabutyl titanate added is 11% of the mass of the sample obtained by calcining in step (5);

[0077] (8) The sample evaporated in step (7) was calcined at 600° C. for 7 h under a nitrogen atmosphere to obtain a catalyst in which Ti was supported on a BiO 2 -CeO 2 composite carrier.

[0078] The reaction conditions of m-ethylphenol and methanol are as follows:

[0079] The catalytic reaction of m-ethylphenol and methanol was carried out in a fixed bed. The amount of m-ethylphenol added was 61% of the total mass of m-ethylphenol and methanol. The reaction temperature was 265°C, the reaction pressure was 0.4 bar(G), and the liquid hourly mass space velocity of m-ethylphenol was 0.3 h -1 .

[0080] After the reaction is stable, samples are taken and the results are analyzed by gas chromatography. The specific results of the embodiment are shown in Table 1.

[0081] Example 4

[0082] The preparation method of the catalyst is as follows:

[0083] (1) preparing a mixed solution with a mass ratio of pure water to ethanol of 0.5, adding a certain amount of bismuth nitrate pentahydrate to the mixed solution of pure water and ethanol, wherein the amount of bismuth nitrate pentahydrate added is 0.21 times the total mass of pure water and ethanol;

[0084] (2) adding a certain amount of anhydrous cerium chloride to the above solution and stirring evenly until dissolved, wherein the mass of the anhydrous cerium chloride is 0.4 times the mass of bismuth nitrate pentahydrate;

[0085] (3) adding a certain amount of dodecyldimethyl (3-sulfopropyl) ammonium hydroxide inner salt to the solution of step (2), the amount added being 0.05 times the mass of the bismuth source;

[0086] (4) adding a certain amount of ammonia water to the solution of step (3) until the pH reaches 6.5;

[0087] (5) filtering and washing the solution in step (4) until it is neutral, and calcining at 450° C. for 4 h in an air atmosphere;

[0088] (6) dispersing a certain amount of titanium n-propoxide in water, wherein the amount of titanium n-propoxide added is 0.2 times the mass of water;

[0089] (7) adding the sample obtained by calcining in step (5) to the solution of step (6), heating under stirring until the water is completely evaporated, wherein the amount of titanium n-propoxide added is 9% of the mass of the sample obtained by calcining in step (5);

[0090] (8) The sample evaporated in step (7) was calcined at 500° C. for 9 h under a nitrogen atmosphere to obtain a catalyst in which Ti was supported on a BiO2-CeO2 composite carrier.

[0091] The reaction conditions of m-ethylphenol and methanol are as follows:

[0092] The catalytic reaction of m-ethylphenol and methanol was carried out in a fixed bed. The amount of m-ethylphenol added was 47% of the total mass of m-ethylphenol and methanol. The reaction temperature was 247°C, the reaction pressure was 0.8 bar(G), and the liquid hourly mass space velocity of m-ethylphenol was 0.5 h -1 .

[0093] After the reaction is stable, samples are taken and the results are analyzed by gas chromatography. The specific results of the embodiment are shown in Table 1.

[0094] Comparative Example 1

[0095] The preparation method of the catalyst is as follows:

[0096] (1) preparing a mixed solution with a mass ratio of pure water to ethanol of 0.5, adding a certain amount of bismuth nitrate pentahydrate to the mixed solution of pure water and ethanol, wherein the amount of bismuth nitrate pentahydrate added is 0.21 times the total mass of pure water and ethanol;

[0097] (2) adding a certain amount of dodecyldimethyl (3-sulfopropyl) ammonium hydroxide inner salt to the solution of step (1), the amount added being 0.05 times the mass of the bismuth source;

[0098] (3) adding a certain amount of ammonia water to the solution of step (2) until the pH reaches 6.5;

[0099] (4) filtering and washing the solution in step (3) until it is neutral, and calcining at 450° C. for 4 h in an air atmosphere;

[0100] (5) dispersing a certain amount of titanium n-propoxide in water, wherein the amount of titanium n-propoxide added is 0.2 times the mass of water;

[0101] (6) adding the sample obtained by calcining in step (5) to the solution of step (6), heating under stirring until the water is completely evaporated, wherein the amount of titanium n-propoxide added is 9% of the mass of the sample obtained by calcining in step (5);

[0102] (7) The sample evaporated in step (6) was calcined at 500° C. for 9 h under a nitrogen atmosphere to obtain a catalyst in which Ti was supported on a BiO2 carrier.

[0103] The reaction conditions of m-ethylphenol and methanol are as follows:

[0104] The catalytic reaction of m-ethylphenol and methanol was carried out in a fixed bed. The amount of m-ethylphenol added was 47% of the total mass of m-ethylphenol and methanol. The reaction temperature was 247°C, the reaction pressure was 0.8 bar(G), and the liquid hourly mass space velocity of m-ethylphenol was 0.5 h -1 .

[0105] After the reaction is stable, samples are taken and the results are analyzed by gas chromatography. The specific results of the embodiment are shown in Table 1.

[0106] Compared with Example 4, in Comparative Example 1, no cerium source was added during the catalyst preparation, and the other preparation conditions and reaction conditions were the same.

[0107] The catalyst prepared in Example 2 was used for life test. The specific reaction steps were the same as in Example 2. After running for 3000 hours, the conversion rate was 98%, the selectivity was 97.2%, and the activity and selectivity did not decrease significantly.

[0108] Table 1 Conversion rate and selectivity of each example

[0109] Serial number m-Ethylphenol conversion rate % m-Ethoxyanisole selectivity % Example 1 93 95 Example 2 99 98 Example 3 91 99 Example 4 85 99 Comparative Example 1 32 69

[0110] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as limiting the present invention. Those skilled in the art will appreciate that, under the guidance of this specification, some modifications or adjustments may be made to the present invention. These modifications or adjustments should also be within the scope defined by the claims of the present invention.

Claims

1. A method for preparing m-ethyl anisole, comprising catalyzing m-ethyl phenol and methanol to generate m-ethyl anisole under the action of a catalyst, wherein: The catalyst is a catalyst in which Ti is supported on a BiO2-CeO2 composite carrier.

2. The method according to claim 1, characterized in that The catalytic reaction of m-ethylphenol and methanol is carried out in a fixed bed; the added amount of m-ethylphenol is 20-70% of the total mass of m-ethylphenol and methanol.

3. The method according to claim 1, characterized in that The reaction temperature of m-ethylphenol and methanol is 230-270°C, the reaction pressure is 0.1-0.3 barG; the liquid hourly mass space velocity of m-ethylphenol is 0.1-1.2 h -1 .

4. The method according to claim 1, characterized in that: The preparation method of the catalyst supported by Ti on a BiO2-CeO2 composite carrier comprises the following steps: (1) adding a certain amount of bismuth source into a mixed solution of pure water and ethanol; (2) adding a certain amount of cerium source to the above solution and stirring until dissolved; (3) adding a certain amount of dodecyldimethyl (3-sulfopropyl) ammonium hydroxide inner salt to the solution of step (2); (4) adding a certain amount of ammonia water to the solution of step (3) until the pH reaches a certain value; (5) filtering and washing the solution in step (4) until it becomes neutral, and roasting it in an air atmosphere for a period of time; (6) dispersing a certain amount of titanium source in water; (7) adding the sample obtained by calcining in step (5) to the solution in step (6), and heating under stirring until the water is evaporated; (8) The sample evaporated in step (7) is calcined for a period of time under a nitrogen atmosphere to obtain a catalyst in which Ti is supported on a BiO2-CeO2 composite carrier.

5. The method according to claim 4, characterized in that In the step (1), the mass ratio of pure water to ethanol is 0.3-0.6, the bismuth source accounts for 0.05-0.3 times the total mass of pure water and ethanol, and the bismuth source is one or more of bismuth acetate, bismuth nitrate pentahydrate and bismuth subnitrate.

6. The method according to claim 4, characterized in that In the step (2), the cerium source is one or more of anhydrous cerium chloride, cerium (III) carbonate hydrate and cerium (III) acetate hydrate, and the amount of the cerium source added is 0.1-0.5 times the mass of the bismuth source.

7. The method according to claim 4, characterized in that In the step (3), the amount of dodecyldimethyl (3-sulfopropyl) ammonium hydroxide inner salt added is 0.01-0.05 of the bismuth source.

8. The method according to claim 4, characterized in that In the step (4), the pH value is controlled to be 5.6-8.3 after adding ammonia water.

9. The method according to claim 4, characterized in that In the step (6), the titanium source is one or more of tetrabutyl titanate, titanium n-propoxide, and titanium tetraisopropoxide; in the step (7), the amount of the titanium source added is 5-15% of the mass of the sample obtained by calcining in step (5).

10. The method according to claim 4, characterized in that In the step (5), the calcination temperature is 300-500° C. and the calcination time is 4-8 hours; in the step (8), the calcination temperature is 400-600° C. and the calcination time is 5-10 hours.

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