Preparation method of methyl anisole

Abstract

The invention relates to a method for directly preparing (methyl) anisole from phenol and methanol, which comprises the following steps: under the action of a composite catalyst, phenol and methanol are catalyzed to generate methyl anisole, and the composite catalyst is prepared by mixing a Ho / beta molecular sieve catalyst and Ti / UiO-66 according to a mass ratio of Ho / beta: Ti / UiO-66 of 0.3-0.6: 1. According to the process, the reaction steps are simple, synthesis is achieved through one step, the total selectivity of methyl anisole reaches 76% or above, and continuous and stable operation can be conducted for 3000 h.

Description

Technical Field

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

[0002] (Methyl) anisole is an important class of chemical intermediates, including anisole, o-methyl anisole, m-methyl anisole and p-methyl anisole. Among them, o-methyl anisole is an organic synthesis intermediate, used in the pesticide industry to make herbicides such as NK-409; m-methyl anisole is a flavor and fragrance intermediate, and a raw material for pressure-sensitive and heat-sensitive dyes; p-methyl anisole is a natural flavor that can be used to prepare various floral flavors and nutty edible flavors.

[0003] At present, the synthesis method of methyl anisole is basically obtained by reacting cresol (o-cresol, m-cresol and p-cresol) with a methylating agent. Patent CN109277115A adopts a molecular sieve catalyst to react o-cresol with methanol to obtain o-methyl anisole. Patent CN111072459B adopts m-cresol and dimethyl sulfate to obtain m-methyl anisole product in the form of cyclic reaction. Patent CN113509947B provides a synthetic method of p-methyl anisole, which adopts p-cresol and dimethyl carbonate to obtain p-methyl anisole under a main catalyst and antioxidant composite system. However, there is a problem in these synthetic methods, the price of cresol is relatively high, and the cost of the prepared methyl anisole is relatively high. How to develop a simple, efficient, low-cost and safe process is a direction that needs to be studied in the future. Summary of the invention

[0004] The object of the present invention is to provide a method for preparing methyl anisole, using a novel catalyst to catalyze phenol and methanol to generate methyl anisole in one step. The process uses phenol, which is cheaper, as a raw material, which greatly reduces the cost compared to cresol. In addition, using methanol as a raw material is cheaper than dimethyl carbonate and dimethyl sulfate used in other industries. Using a continuous fixed bed process, the reaction efficiency is high, no other solvents need to be used, and the separation cost is low. In addition, the reaction steps are simple, synthesis is achieved in one step, and it has good reactivity and selectivity, and can achieve long-term stable operation, which is an ideal process for industrial production.

[0005] In one aspect, the present invention provides a method for preparing methyl anisole, the method comprising: catalyzing phenol and methanol to generate methyl anisole under the action of a composite catalyst.

[0006] Preferably, the reaction of phenol and methanol adopts a continuous fixed bed reaction.

[0007] Preferably, the amount of phenol added is 0.1-0.7 of the total mass of phenol and methanol.

[0008] Preferably, the reaction temperature of phenol and methanol is 240-360°C, the reaction pressure is 0.5-4.5 bar(A), and the liquid hourly mass space velocity of phenol is 0.05-0.6 h -1 .

[0009] Preferably, the composite catalyst is a composite catalyst in which a Ho / β molecular sieve catalyst and Ti / UiO-66 are mixed in a certain proportion; preferably, in the composite catalyst, the mass ratio of Ho / β:Ti / UiO-66 is 0.3-0.6:1, and the two catalysts are physically mixed.

[0010] In the present invention, the preparation process of the Ho / β molecular sieve comprises the following steps:

[0011] (1) dissolving a holmium source in distilled water to obtain an aqueous solution of the holmium source;

[0012] (2) dissolving the β molecular sieve in an aqueous solution of a holmium source and immersing the sieve;

[0013] (3) Drying and calcining the impregnated sample to obtain a Ho / β molecular sieve catalyst.

[0014] Preferably, in step (1), the holmium source is one or more of holmium chloride, holmium acetylacetonate, holmium acetate hydrate and holmium nitrate pentahydrate, and the mass of the holmium source is 0.1-0.6 times the mass of water;

[0015] Preferably, the β molecular sieve in step (2) is one or more of NKF-6-25H, NKF-6-30H, NKF-6-40H, NKF-6-60H and NKF-6-100H sold by Tianjin Nanhua Catalyst Co., Ltd.

[0016] Preferably, the mass of the holmium source in step (2) is 0.2-0.8 of that of the β molecular sieve; the impregnation is carried out at room temperature for 12-48 hours;

[0017] Preferably, the drying temperature in step (3) is 100-110° C., and the drying time is 5-12 h;

[0018] Preferably, in step (3), calcination is performed at 400-650° C. for 4-12 hours.

[0019] In the present invention, the preparation process of Ti / UiO-66 comprises the following steps:

[0020] (1) dissolving a certain amount of zirconium source, titanium source and solvent A in solvent B;

[0021] (2) placing the dissolved solution into a reactor for reaction;

[0022] (3) After the reaction is completed, washing with solvent B and centrifuging;

[0023] (4) Dry the centrifuged sample to obtain the Ti / UiO-66 catalyst.

[0024] Preferably, in step (1), the zirconium source is one or more of zirconium chloride, zirconium fluoride and zirconium acetylacetonate, the titanium source is one or more of titanium tetrachloride, tetrabutyl titanate and titanium tetrafluoride, the solvent A is one or more of phthalic acid, isophthalic acid and terephthalic acid, and the solvent B is one or more of N,N-dimethylformamide and N,N-dimethylacetamide;

[0025] Preferably, in step (1), the mass of solvent B is 50-150 times the mass of the zirconium source;

[0026] Preferably, in step (1), the mass of the titanium source is 0.02-0.2 times the mass of the zirconium source;

[0027] Preferably, in step (1), the mass of solvent A is 0.5-1.5 times the mass of the zirconium source;

[0028] Preferably, in step (2), the reaction temperature is 60-140° C. and the reaction time is 3-48 h;

[0029] Preferably, in step (4), the drying temperature is 60-120° C. and the drying time is 6-24 h.

[0030] The beneficial effects of the present invention are:

[0031] 1. The present invention provides a novel synthesis process of methyl anisole;

[0032] 2. The present invention develops a highly efficient catalyst, using a continuous fixed bed process, with a selectivity of methyl anisole of more than 76%, and can operate stably for 3000 hours. The Ti / UiO-66 catalyst can provide suitable acidity and alkalinity to promote the adsorption of phenol and methanol. Ho forms a highly active catalytic active center under the confinement of the β molecular sieve, which can promote the reaction of phenol and methanol. DETAILED DESCRIPTION

[0033] 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.

[0034] The present invention is further described below with reference to the embodiments, but does not constitute any limitation.

[0035] Reactor used in the embodiment: The reaction adopts a fixed bed reactor made of 316L material, the inner diameter of the reaction tube is 20mm, and 316L distillation filler is filled at both ends of the catalyst.

[0036] The composition of the m-cresol-ethanol reaction solution was analyzed by gas chromatography, and the operating conditions were: Shimadzu GC-2030 gas chromatograph, GL C18-H 5um 4.6X50mm chromatographic column, N,N-dimethylformamide as diluent. The vaporization chamber temperature was 320°C, the column flow rate was 0.8.00mL / min, and the injection volume was 0.3μL. The chromatographic column was programmed to heat: first, the temperature was increased from 40°C to 160°C at a heating rate of 3°C / min, and finally, the temperature was increased to 270°C at a heating rate of 5°C / min.

[0037] The raw materials in the examples are shown in Table 1.

[0038] Table 1 Source of raw materials

[0039]

[0040] Embodiment 1:

[0041] The preparation method of the catalyst is as follows:

[0042] The catalyst is a composite catalyst in which Ho / β molecular sieve and Ti / UiO-66 are mixed in a certain proportion; the mass of Ho / β is 0.6 times the mass of Ti / UiO-66, and the two catalysts are uniformly mixed.

[0043] The preparation process of Ho / β molecular sieve includes the following steps:

[0044] (1) dissolving 100 g of holmium chloride in distilled water, wherein the mass of the holmium source is 0.3 times the mass of the distilled water, to obtain an aqueous solution of holmium chloride;

[0045] (2) dissolving the β molecular sieve (NKF-6-25H) in an aqueous solution of holmium chloride and immersing at room temperature for 24 hours, wherein the mass of holmium chloride is 0.4 times that of the β molecular sieve;

[0046] (3) Dry the impregnated sample at 110 °C for 12 h;

[0047] (4) The dried sample was calcined at 450°C for 5 h in air atmosphere to obtain a Ho / β molecular sieve catalyst.

[0048] The preparation process of Ti / UiO-66 includes the following steps:

[0049] (1) Zirconium acetylacetonate (100 g), titanium tetrachloride and isophthalic acid are dissolved in an N,N-dimethylformamide solution, wherein the mass of N,N-dimethylformamide is 65 times the mass of zirconium acetylacetonate, the mass of titanium tetrachloride is 0.18 times the mass of zirconium acetylacetonate, and the mass of isophthalic acid is 1.2 times the mass of zirconium acetylacetonate.

[0050] (2) Place the dissolved solution into a polytetrafluoroethylene autoclave and react at 70°C for 5 hours;

[0051] (3) After the reaction, wash with N,N-dimethylformamide and centrifuge three times;

[0052] (4) drying the centrifuged sample at 100° C. for 10 h to obtain a Ti / / UiO-66 catalyst;

[0053] The reaction conditions of phenol and methanol are as follows:

[0054] The reaction of phenol and methanol adopts a continuous fixed bed reaction. The amount of phenol added is 0.4 of the total mass of phenol and methanol. The reaction temperature of phenol and methanol is 260°C, the reaction pressure is 2.3 bar (A), and the liquid hourly mass space velocity of phenol is 0.5 h -1 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] Embodiment 2:

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

[0057] The catalyst is a composite catalyst in which Ho / β molecular sieve and Ti / UiO-66 are mixed in a certain proportion; the mass of Ho / β is 0.4 of the mass of Ti / UiO-66, and the two catalysts are uniformly mixed.

[0058] The preparation process of Ho / β molecular sieve includes the following steps:

[0059] (1) dissolving 100 g of holmium acetate hydrate in distilled water, wherein the mass of the holmium source is 0.4 times the mass of the distilled water, to obtain an aqueous solution of holmium acetate hydrate;

[0060] (2) dissolving the β molecular sieve (NKF-6-40H) in an aqueous solution of holmium acetate and immersing at room temperature for 24 hours, wherein the mass of the holmium acetate hydrate is 0.8 times that of the β molecular sieve;

[0061] (3) Dry the impregnated sample at 110 °C for 12 h;

[0062] (4) The dried sample was calcined at 600°C for 11 h in air atmosphere to obtain a Ho / β molecular sieve catalyst.

[0063] The preparation process of Ti / UiO-66 includes the following steps:

[0064] (1) Zirconium chloride (100 g), tetrabutyl titanate and terephthalic acid are dissolved in N,N-dimethylacetamide solution, wherein the mass of N,N-dimethylacetamide is 78 times the mass of zirconium chloride, the mass of titanium tetrachloride is 0.11 times the mass of zirconium chloride, and the mass of terephthalic acid is 1.0 times the mass of zirconium chloride.

[0065] (2) Place the dissolved solution into a polytetrafluoroethylene autoclave and react at 120°C for 15 hours;

[0066] (3) After the reaction, wash with N,N-dimethylacetamide and centrifuge three times;

[0067] (4) Drying the centrifuged sample at 110° C. for 6 h to obtain a Ti / / UiO-66 catalyst;

[0068] The reaction conditions of phenol and methanol are as follows:

[0069] The reaction of phenol and methanol adopts a continuous fixed bed reaction. The amount of phenol added is 0.5 of the total mass of phenol and methanol. The reaction temperature of phenol and methanol is 280°C, the reaction pressure is 1.2 bar (A), and the liquid hourly mass space velocity of phenol is 0.4h -1 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.

[0070] Embodiment 3:

[0071] The preparation method of the catalyst is as follows:

[0072] The catalyst is a composite catalyst of Ho / β molecular sieve and Ti / UiO-66 mixed in a certain proportion; the mass of Ho / β is 0.3 of the mass of Ti / UiO-66, and the two catalysts are uniformly mixed.

[0073] The preparation process of Ho / β molecular sieve includes the following steps:

[0074] (1) dissolving 100 g of holmium acetylacetonate in distilled water, wherein the mass of the holmium source is 0.2 times the mass of the distilled water, to obtain an aqueous solution of holmium acetylacetonate;

[0075] (2) dissolving the β molecular sieve (NKF-6-30H) in an aqueous solution of holmium acetylacetonate and immersing at room temperature for 24 hours, wherein the mass of holmium acetylacetonate is 0.6 times that of the β molecular sieve;

[0076] (3) Dry the impregnated sample at 110 °C for 12 h;

[0077] (4) The dried sample was calcined at 550 °C for 7 h in air atmosphere to obtain a Ho / β molecular sieve catalyst.

[0078] The preparation process of Ti / UiO-66 includes the following steps:

[0079] (1) Zirconium fluoride (100 g), tetrabutyl titanate and phthalic acid are dissolved in N,N-dimethylformamide solution, wherein the mass of N,N-dimethylformamide is 129 times the mass of zirconium fluoride, the mass of tetrabutyl titanate is 0.04 times the mass of zirconium fluoride, and the mass of phthalic acid is 0.6 times the mass of zirconium fluoride.

[0080] (2) placing the dissolved solution into a polytetrafluoroethylene autoclave and reacting at 80°C for 43 hours;

[0081] (3) After the reaction, wash with N,N-dimethylformamide and centrifuge three times;

[0082] (4) drying the centrifuged sample at 80° C. for 20 h to obtain a Ti / / UiO-66 catalyst;

[0083] The reaction conditions of phenol and methanol are as follows:

[0084] The reaction of phenol and methanol adopts a continuous fixed bed reaction. The amount of phenol added is 0.3 of the total mass of phenol and methanol. The reaction temperature of phenol and methanol is 340°C, the reaction pressure is 0.7 bar (A), and the liquid hourly mass space velocity of phenol is 0.15h -1 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.

[0085] Embodiment 4:

[0086] The preparation method of the catalyst is as follows:

[0087] The catalyst is a composite catalyst of Ho / β molecular sieve and Ti / UiO-66 mixed in a certain proportion; the mass of Ho / β is 0.5 of the mass of Ti / UiO-66, and the two catalysts are uniformly mixed.

[0088] The preparation process of Ho / β molecular sieve includes the following steps:

[0089] (1) dissolving 100 g of holmium nitrate in distilled water, wherein the mass of the holmium source is 0.6 times the mass of the distilled water, to obtain an aqueous solution of holmium nitrate;

[0090] (2) dissolving the β molecular sieve (NKF-6-100H) in an aqueous solution of holmium nitrate and immersing at room temperature for 24 hours, wherein the mass of holmium nitrate is 0.3 times that of the β molecular sieve;

[0091] (3) Dry the impregnated sample at 110 °C for 12 h;

[0092] (4) The dried sample was calcined at 500°C for 10 h in air atmosphere to obtain a Ho / β molecular sieve catalyst.

[0093] The preparation process of Ti / UiO-66 includes the following steps:

[0094] (1) Zirconium acetylacetonate (100 g), titanium tetrachloride and isophthalic acid are dissolved in N,N-dimethylacetamide solution, wherein the mass of N,N-dimethylformamide is 104 times the mass of zirconium acetylacetonate, the mass of titanium tetrachloride is 0.07 times the mass of zirconium acetylacetonate, and the mass of isophthalic acid is 0.9 times the mass of zirconium acetylacetonate.

[0095] (2) Place the dissolved solution into a polytetrafluoroethylene autoclave and react at 110°C for 29 hours;

[0096] (3) After the reaction, wash with N,N-dimethylacetamide and centrifuge three times;

[0097] (4) Drying the centrifuged sample at 90° C. for 15 h to obtain a Ti / / UiO-66 catalyst;

[0098] The reaction conditions of phenol and methanol are as follows:

[0099] The reaction of phenol and methanol adopts a continuous fixed bed reaction. The amount of phenol added is 0.2 of the total mass of phenol and methanol. The reaction temperature of phenol and methanol is 300°C, the reaction pressure is 3.8 bar (A), and the liquid hourly mass space velocity of phenol is 2.5h -1 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.

[0100] 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 41% and the selectivity was 76%. The activity and selectivity did not decrease significantly.

[0101] Comparative Example 1:

[0102] The preparation method of the catalyst is basically the same as that of Example 1, the only difference being that the Ti / UiO-66 catalyst is not added. The reaction conditions of phenol and methanol are the same as those of Example 1.

[0103] Comparative Example 2:

[0104] The preparation method of the catalyst is basically the same as that of Example 1, the only difference being that the Ho / β molecular sieve is not added. The reaction conditions of phenol and methanol are the same as those of Example 1.

[0105] Table 2 Conversion rate and selectivity of each example

[0106]

[0107]

[0108] 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 methyl anisole, characterized in that, The method comprises: catalyzing phenol and methanol to generate methyl anisole under the action of a composite catalyst, wherein the composite catalyst is a composite catalyst in which a Ho / β molecular sieve catalyst and Ti / UiO-66 are mixed at a mass ratio of Ho / β:Ti / UiO-66 of 0.3-0.6:

1.

2. The preparation method according to claim 1, characterized in that The amount of phenol added is 0.1-0.7 of the total mass of phenol and methanol.

3. The preparation method according to claim 1 or 2, characterized in that: The reaction temperature of phenol and methanol is 240-360°C, the reaction pressure is 0.5-4.5 bar (A), and the liquid hourly mass space velocity of phenol is 0.05-0.6 h -1 .

4. The preparation method according to any one of claims 1 to 3, characterized in that: The preparation process of the Ho / β molecular sieve comprises the following steps: (1) dissolving a holmium source in distilled water to obtain an aqueous solution of the holmium source; (2) dissolving the β molecular sieve in an aqueous solution of a holmium source and immersing the sieve; (3) Drying and calcining the impregnated sample to obtain a Ho / β molecular sieve catalyst.

5. The preparation method according to claim 4, characterized in that: In step (1), the holmium source is one or more of holmium chloride, holmium acetylacetonate, holmium acetate hydrate and holmium nitrate pentahydrate, and the mass of the holmium source is 0.1-0.6 times the mass of water; and / or, the beta molecular sieve in step (2) is one or more of NKF-6-25H, NKF-6-30H, NKF-6-40H, NKF-6-60H and NKF-6-100H produced by Tianjin Nanhua Catalyst Co., Ltd.

6. The preparation method according to claim 4 or 5, characterized in that: In step (2), the mass of the holmium source is 0.2-0.8 of the mass of the β molecular sieve; the impregnation is carried out at room temperature for 12-48 hours; And / or, in step (3), the drying temperature is 100-110° C., and the drying time is 5-12 h; and / or, in step (3), the calcination is performed at 400-650° C. for 4-12 h.

7. The preparation method according to any one of claims 1 to 6, characterized in that: The preparation process of Ti / UiO-66 includes the following steps: (1) dissolving a certain amount of zirconium source, titanium source and solvent A in solvent B; (2) placing the dissolved solution into a reactor for reaction; (3) After the reaction is completed, washing with solvent B and centrifuging; (4) Dry the centrifuged sample to obtain the Ti / UiO-66 catalyst.

8. The preparation method according to claim 7, characterized in that: In step (1), the zirconium source is one or more of zirconium chloride, zirconium fluoride and zirconium acetylacetonate, the titanium source is one or more of titanium tetrachloride, tetrabutyl titanate and titanium tetrafluoride, the solvent A is one or more of phthalic acid, isophthalic acid and terephthalic acid, and the solvent B is one or more of N,N-dimethylformamide and N,N-dimethylacetamide.

9. The preparation method according to claim 7 or 8, characterized in that: In step (1), the mass of solvent B is 50-150 times the mass of the zirconium source; and / or, the mass of the titanium source in step (1) is 0.02-0.2 times the mass of the zirconium source; and / or, the mass of solvent A in step (1) is 0.5-1.5 times the mass of the zirconium source.

10. The preparation method according to any one of claims 7 to 9, characterized in that: In step (2), the reaction temperature is 60-140° C. and the reaction time is 3-48 h; and / or, in step (4), the drying temperature is 60-120° C. and the drying time is 6-24 h.

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