Catalyst for preparing methyl formate through alcoholysis of amide compound as well as preparation method and application of catalyst

Abstract

The invention relates to a catalyst for preparing methyl formate through alcoholysis of an amide compound and a preparation method and application of the catalyst, the catalyst for preparing methyl formate through alcoholysis of the amide compound comprises a calcium-magnesium composite oxide and a hydrophobic modifier, the catalyst is subjected to hydrophobic modification treatment, and the stability and activity of the catalyst are improved. The catalyst and application provided by the invention have the characteristics of high catalyst stability, high amide compound conversion efficiency, high methyl formate selectivity and the like.

Description

Technical Field

[0001] The invention relates to the field of preparation of organic amine compounds and ester compounds, in particular to a catalyst for preparing methyl formate by alcoholysis of amide compounds, and a preparation method and application thereof. Background Art

[0002] Amide alcoholysis reaction refers to the reaction of amide compounds and alcohols to generate organic amines and corresponding ester compounds under the action of a catalyst. CN109053644A discloses a rapid synthesis method of biomass-based amines, which uses formamide as an amine source, formic acid as a hydrogen source, and biomass aldehydes and ketones as raw materials. Under microwave-assisted heating and in the absence of solvents and catalysts, formamide and aldehydes and ketones are directly added by rapid heating and reduced with formic acid to prepare the corresponding formamide derivatives; the formamide derivatives are selectively converted into corresponding primary amines by alcoholysis under the action of alkali. The method is to dissolve the formamide derivative in methanol, react at 60 to 100 ° C for 2 to 8 hours under the action of alkali to obtain a primary amine; wherein the alkali is a homogeneous strong base such as sodium hydroxide, cesium carbonate, sodium ethoxide, etc. It can be seen that although the amide bond is a relatively stable chemical bond, an appropriate reaction system can efficiently convert amide compounds into organic amines and ester products.

[0003] However, in the prior art, the amide alcoholysis reaction mainly uses a homogeneous alkaline catalyst, which has problems such as difficulty in subsequent separation, high environmental protection requirements, and high cost. Summary of the invention

[0004] The purpose of the present invention is to provide a catalyst for preparing methyl formate by alcoholysis of amide compounds, a preparation method and application thereof, based on the prior art, so as to solve the problem of poor catalyst stability in the prior art.

[0005] The first aspect of the present invention provides a catalyst for preparing methyl formate by alcoholysis of amide compounds. The catalyst for preparing methyl formate by alcoholysis of amide compounds comprises a calcium-magnesium composite oxide and a hydrophobic modifier. In the calcium-magnesium composite oxide, the molar ratio of calcium to magnesium is 0.1 to 10:1. The hydrophobic modifier is a halogenated hydrocarbon. The mass percentage of the hydrophobic modifier is 0.01 to 1 mass % of the calcium-magnesium composite oxide.

[0006] In one embodiment of the present invention, in the calcium-magnesium composite oxide, the molar ratio of calcium to magnesium is 0.5 to 8:1.

[0007] In one embodiment of the present invention, the specific surface area of ​​the calcium-magnesium composite oxide is 10 to 60 m 2 / g.

[0008] In one embodiment of the present invention, the hydrophobic modifier is one or more selected from ethyl bromide, ethyl iodide, propyl bromide, propyl iodide, butyl bromide, butyl iodide, benzyl bromide or benzyl iodide.

[0009] In one embodiment of the present invention, the mass percentage of the hydrophobic modifier is 0.05 to 0.1 mass % based on the calcium magnesium composite oxide.

[0010] In order to enhance the stability of the catalyst in the reaction environment, in one embodiment of the present invention, the contact angle of the catalyst for preparing methyl formate by alcoholysis of amide compounds is 100 to 180°, preferably 140 to 180°. The contact angle refers to the angle between the solid-liquid interface, the liquid interior and the gas-liquid interface of the catalyst at the junction of solid, liquid and gas phases.

[0011] The second aspect of the present invention provides a method for preparing any of the above catalysts, comprising:

[0012] The calcium-magnesium composite oxide is dispersed in a solution containing a hydrophobic modifier, stirred at a certain temperature for hydrophobic modification, and after solid-liquid separation, the modified solid is vacuum dried to obtain a catalyst for preparing methyl formate by alcoholysis of amide compounds;

[0013] The solvent used for the solution containing the hydrophobic modifier is one or more selected from methanol, ethanol or acetone, the temperature of hydrophobic modification is 20-70°C, the time of hydrophobic modification is 1-6h, and when the modified solid is dried, the drying temperature is 50-100°C, and the drying time is 3-6h.

[0014] The present invention has no limitation on the preparation method of the calcium-magnesium composite oxide, and any preparation method for obtaining the composite metal oxide may be used.

[0015] In one embodiment of the present invention, the calcium-magnesium composite oxide is prepared by at least one of a hydrothermal method, a coprecipitation method, a sol-gel method, and a microemulsion method.

[0016] In a preferred embodiment of the present invention, the calcium-magnesium composite oxide is prepared by a co-precipitation method, specifically, a calcium precursor and a magnesium precursor are prepared into a mixed aqueous solution, and then an excess of ammonium carbonate precipitant is added to the mixed aqueous solution at room temperature, or the mixed aqueous solution and the ammonium carbonate precipitant are respectively dripped into a precipitation tank for co-precipitation by a parallel flow co-precipitation method; after the precipitation is completed, the mixture is allowed to stand for aging, and a white precipitate is obtained after filtering, washing and drying, and the white precipitate is roasted to obtain the calcium-magnesium composite oxide.

[0017] In one embodiment of the present invention, the precursor of calcium and the precursor of magnesium are independently selected from one or more of the acetates, nitrates and chlorides of calcium and magnesium; the molar ratio of calcium to magnesium is 0.1 to 10:1, preferably 0.5 to 8:1; the coprecipitation time is 1 to 6 hours; the calcination temperature is 800 to 1000°C; and the calcination time is 3 to 6 hours.

[0018] The third aspect of the present invention provides an application method of any of the above catalysts, comprising: in a kettle reactor, dissolving an amide compound in alcohol, charging a protective gas of a certain pressure, reacting under alcoholysis reaction conditions under the action of a catalyst for preparing methyl formate by alcoholysis of the amide compound, to obtain an organic amine compound and an ester compound; the alcoholysis reaction conditions are: a reaction temperature of 50 to 150° C., an initial reaction pressure of 0.1 to 6 bar, and a reaction time of 1 to 12 hours;

[0019] In one embodiment of the present invention, the amide compound is selected from one or more of N-formylmorpholine, N-methylformamide, N,N-dimethylformamide, N-isobutylformamide, and N-cyclohexylformamide.

[0020] In one embodiment of the present invention, the alcohol is methanol.

[0021] In one embodiment of the present invention, the ratio of the amide compound to the alcohol is 1 mol:100L to 1 mol:5L, preferably 1 mol:50L to 1 mol:20L.

[0022] In one embodiment of the present invention, the ratio of the amide compound to the catalyst for preparing methyl formate by alcoholysis of the amide compound is 1 mol:200 g to 1 mol:10 g, preferably 1 mol:120 g to 1 mol:80 g.

[0023] In one embodiment of the present invention, the alcoholysis reaction conditions are: reaction temperature 60-90° C., initial reaction pressure 1-5 bar, reaction time 4-8 h;

[0024] The protective gas is selected from one or more of nitrogen, argon, helium and hydrogen.

[0025] In one embodiment of the present invention, the amide compound is N-formylmorpholine, and the alcohol is methanol. Under the action of the catalyst of the present invention, the reaction is carried out under alcoholysis reaction conditions to obtain morpholine and methyl formate.

[0026] In one embodiment of the present invention, the amide compound is N,N-dimethylformamide, and the alcohol is methanol. Under the action of the catalyst of the present invention, the reaction is carried out under alcoholysis reaction conditions to obtain N,N-dimethylamine and methyl formate.

[0027] The invention provides a catalyst for preparing methyl formate by alcoholysis of hydrophobic amide compounds, wherein the catalyst has a hydrophobic function by modifying calcium-magnesium composite oxide with a hydrophobic modifier. The hydrophobic ability of the catalyst for preparing methyl formate by alcoholysis of hydrophobic amide compounds provided by the invention can prevent a trace amount of water from accelerating the loss and deactivation of active components during the alcoholysis reaction, thereby improving the stability of the amide alcoholysis catalyst and reducing the influence of water on the active center, thereby improving the activity of the catalyst.

[0028] The invention provides a method for applying a catalyst for preparing methyl formate by alcoholysis of hydrophobic amide compounds, which has the characteristics of high product selectivity, high yield, good catalyst stability, etc., and has low equipment requirements, small investment, and low operating cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The graph is a reaction result diagram of the conversion rate of the raw material formylmorpholine and the molar selectivity of the product morpholine and methyl formate for different reaction times in Example 9.

[0030] Figure 2 The figure is a reaction result diagram of the conversion rate of the raw material formylmorpholine and the molar selectivity of the product morpholine and methyl formate for different reaction times in Comparative Example 3. DETAILED DESCRIPTION

[0031] The following examples will further illustrate the present invention, but should not be construed as limiting the present invention.

[0032] In the embodiments and comparative examples, the calculation formulas for conversion and selectivity are as follows:

[0033]

[0034]

[0035]

[0036] Where X is the conversion rate, S is the molar selectivity, and n in is the amount of substance before the reaction, n out is the amount of substance after the reaction.

[0037] The contact angle of the catalyst was measured using a JC2000C1 contact angle meter.

[0038] The following Preparation Examples 1-5 are used to illustrate the catalyst for preparing methyl formate by amide alcoholysis of the present invention and the preparation method thereof.

[0039] Preparation Example 1

[0040] Commercially purchased calcium acetate and magnesium acetate are used as calcium and magnesium precursors to prepare a mixed aqueous solution with calcium and magnesium ion molar concentrations of a mol / L and b mol / L, respectively, and then an excess of ammonium carbonate precipitant is added to the solution, and a white precipitate is obtained after filtering, washing and drying. After the white precipitate is fully ground, it is calcined in a muffle furnace at 900° C. in a nitrogen atmosphere for 6 hours to obtain a calcium-magnesium composite oxide, recorded as a / b-CaMg, which is stored in a desiccator for later use.

[0041] By adjusting the molar concentration of calcium and magnesium ions, calcium-magnesium composite oxides with different calcium-magnesium ratios can be obtained, such as 1 / 1-CaMg (specific surface area of ​​38.5 m 2 / g), 1 / 1.5-CaMg ((specific surface area of ​​46.3m 2 / g).

[0042] Preparation Example 2

[0043] The calcium magnesium composite oxide 1 / 1-CaMg prepared in Preparation Example 1 was dispersed in a methanol solution of ethyl bromide, wherein the amount of ethyl bromide added to the solution was 0.05% of the mass of the calcium magnesium composite oxide 1 / 1-CaMg. The obtained solid-liquid mixture was stirred at 60° C. for 4 h for hydrophobic modification, and after solid-liquid separation, the obtained modified solid was vacuum dried at 70° C. for 4 h to obtain the catalyst 1 / 1-CaMg-1 for preparing methyl formate by alcoholysis of amide compounds.

[0044] Preparation Example 3

[0045] The calcium magnesium composite oxide 1 / 1-CaMg prepared in Preparation Example 1 was dispersed in a methanol solution of benzyl bromide, wherein the amount of benzyl bromide added to the solution was 0.05% of the mass of the calcium magnesium composite oxide 1 / 1-CaMg. The obtained solid-liquid mixture was stirred at 60° C. for 4 h for hydrophobic modification, and after solid-liquid separation, the obtained modified solid was vacuum dried at 70° C. for 4 h to obtain the catalyst 1 / 1-CaMg-2 for preparing methyl formate by alcoholysis of amide compounds.

[0046] Preparation Example 4

[0047] The calcium magnesium composite oxide 1 / 1.5-CaMg prepared in Preparation Example 1 was dispersed in a methanol solution of ethyl bromide, wherein the amount of ethyl bromide added to the solution was 0.05% of the mass of the calcium magnesium composite oxide 1 / 1.5-CaMg. The obtained solid-liquid mixture was stirred at 60° C. for 4 h for hydrophobic modification, and after solid-liquid separation, the obtained modified solid was vacuum dried at 70° C. for 4 h to obtain the catalyst 1 / 1.5-CaMg-1 for preparing methyl formate by alcoholysis of amide compounds.

[0048] Preparation Example 5

[0049] The calcium magnesium composite oxide 1 / 1-CaMg prepared in Preparation Example 1 was dispersed in a methanol solution of ethyl bromide, wherein the amount of ethyl bromide added to the solution was 0.08% of the mass of the calcium magnesium composite oxide 1-CaO-1-MgO. The obtained solid-liquid mixture was stirred at 60° C. for 4 h for hydrophobic modification, and after solid-liquid separation, the obtained modified solid was vacuum dried at 70° C. for 4 h to obtain the catalyst 1 / 1-CaMg-3 for preparing methyl formate by alcoholysis of amide compounds.

[0050] Examples 1-9 and Comparative Examples 1-3 are used to illustrate the use of the catalyst for preparing methyl formate by alcoholysis of the amide compounds obtained in Preparation Examples 1-5 of the present invention.

[0051] Example 1

[0052] 2 mmol of formylmorpholine, 50 mL of methanol and 0.1 g of the 1 / 1-CaMg-1 catalyst obtained in Preparation Example 2 were placed in a reactor, filled with 5 bar of high-purity nitrogen as a protective gas, and reacted at 60° C. for 6 h. The raw materials and products in the reaction solution were analyzed by gas chromatography, and the conversion rate of the raw material formylmorpholine and the molar selectivity of the product morpholine and methyl formate were calculated. The results are shown in Table 1.

[0053] Example 2

[0054] 2 mmol of formylmorpholine, 50 mL of methanol and 0.1 g of the 1 / 1-CaMg-2 catalyst obtained in Preparation Example 3 were placed in a reaction kettle, filled with 5 bar of high-purity nitrogen as a protective gas, and reacted at 60° C. for 6 hours. The raw materials and products in the reaction solution were analyzed by gas chromatography, and the conversion rate of the raw material formylmorpholine and the molar selectivity of the product morpholine and methyl formate were calculated. The results are shown in Table 1.

[0055] Example 3

[0056] 2 mmol of formylmorpholine, 50 mL of methanol and 0.1 g of the 1 / 1.5-CaMg-1 catalyst obtained in Preparation Example 4 were placed in a reactor, filled with 5 bar of high-purity nitrogen as a protective gas, and reacted at 60° C. for 6 h. The raw materials and products in the reaction solution were analyzed by gas chromatography, and the conversion rate of the raw material formylmorpholine and the molar selectivity of the product morpholine and methyl formate were calculated. The results are shown in Table 1.

[0057] Example 4

[0058] 2 mmol of formylmorpholine, 50 mL of methanol and 0.1 g of the 1 / 1-CaMg-3 catalyst obtained in Preparation Example 5 were placed in a reaction kettle, filled with 5 bar of high-purity nitrogen as a protective gas, and reacted at 60° C. for 6 hours. The raw materials and products in the reaction solution were analyzed by gas chromatography, and the conversion rate of the raw material formylmorpholine and the molar selectivity of the product morpholine and methyl formate were calculated. The results are shown in Table 1.

[0059] Example 5

[0060] 2 mmol N-formylmorpholine, 50 mL methanol and 0.1 g 1 / 1-CaMg-1 catalyst obtained in Preparation Example 2 were placed in a reaction kettle, filled with 5 bar high-purity nitrogen as a protective gas, and reacted at 60° C. for 3 h. The raw materials and products in the reaction solution were analyzed by gas chromatography, and the conversion rate of the raw material formylmorpholine and the molar selectivity of the product morpholine and methyl formate were calculated. The results are shown in Table 1.

[0061] Example 6

[0062] 2 mmol N-formylmorpholine, 50 mL methanol and 0.1 g 1 / 1-CaMg-1 catalyst obtained in Preparation Example 2 were placed in a reaction kettle, filled with 5 bar of high-purity nitrogen as a protective gas, and reacted at 80° C. for 6 h. The raw materials and products in the reaction solution were analyzed by gas chromatography, and the conversion rate of the raw material formylmorpholine and the molar selectivity of the product morpholine and methyl formate were calculated. The results are shown in Table 1.

[0063] Example 7

[0064] 2mmol N,N-dimethylformamide, 50mL methanol and 0.1g 1 / 1-CaMg-1 catalyst obtained in Preparation Example 2 were placed in a reactor, filled with 5bar high-purity nitrogen as a protective gas, and reacted at 60°C for 6h. The raw materials and products in the reaction solution were analyzed by gas chromatography, and the conversion rate of the raw material N,N-dimethylformamide and the molar selectivity of the product N,N-dimethylamine and methyl formate were calculated. The results are shown in Table 1.

[0065] Example 8

[0066] 2mmol N-formylmorpholine, 2mmol water, 50mL methanol and 0.1g 1 / 1-CaMg-1 catalyst obtained in Preparation Example 2 were placed in a reaction kettle, filled with 5bar high-purity nitrogen as a protective gas, and reacted at 60°C for 6h. The raw materials and products in the reaction solution were analyzed by gas chromatography, and the conversion rate of the raw material formylmorpholine and the molar selectivity of the product morpholine and methyl formate were calculated. The results are shown in Table 1.

[0067] Example 9

[0068] The catalyst used in Example 1 was filtered and washed with methanol three times, and then reused 10 times according to the conditions in Example 1. The concentrations of the raw materials and products in the reaction solution were analyzed by gas chromatography, and the conversion rate of the raw material formylmorpholine and the molar selectivity of the product morpholine and methyl formate were calculated. The reaction results of different reaction times are shown in Figure 1 .

[0069] Comparative Example 1

[0070] 2 mmol of N-formylmorpholine, 50 mL of methanol and 0.1 g of the 1 / 1-CaMg catalyst obtained in Preparation Example 1 were placed in a reaction kettle, filled with 5 bar of high-purity nitrogen as a protective gas, and reacted at 60° C. for 6 hours. The raw materials and products in the reaction solution were analyzed by gas chromatography, and the conversion rate of the raw material formylmorpholine and the molar selectivity of the product morpholine and methyl formate were calculated. The results are shown in Table 1.

[0071] Comparative Example 2

[0072] 2 mmol N-formylmorpholine, 2 mmol water, 50 mL methanol and 0.1 g 1 / 1-CaMg catalyst obtained in Preparation Example 1 were placed in a reaction kettle, filled with 5 bar high-purity nitrogen as a protective gas, and reacted at 60° C. for 6 h. The raw materials and products in the reaction solution were analyzed by gas chromatography, and the conversion rate of the raw material formylmorpholine and the molar selectivity of the product morpholine and methyl formate were calculated. The results are shown in Table 1.

[0073] Comparative Example 3

[0074] The catalyst used in Comparative Example 1 was filtered and washed with methanol three times, and then reused 10 times according to the conditions in Example 1. The concentrations of the raw materials and products in the reaction solution were analyzed by gas chromatography, and the conversion rate of the raw material formylmorpholine and the molar selectivity of the product morpholine and methyl formate were calculated. The reaction results of different reaction times are shown in Figure 2 .

[0075] Table 1

[0076]

[0077] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A catalyst for preparing methyl formate by alcoholysis of amide compounds, characterized in that: The catalyst for preparing methyl formate by alcoholysis of amide compounds includes calcium-magnesium composite oxide and a hydrophobic modifier, wherein the molar ratio of calcium to magnesium in the calcium-magnesium composite oxide is 0.1-10:1, and the hydrophobic modifier is a halogenated hydrocarbon, and the mass percentage of the hydrophobic modifier is 0.01-1 mass % of the calcium-magnesium composite oxide.

2. The catalyst according to claim 1, characterized in that In the calcium-magnesium composite oxide, the molar ratio of calcium to magnesium is 0.5 to 8:1; The specific surface area of ​​calcium magnesium composite oxide is 10~60m 2 / g.

3. The catalyst according to claim 1, characterized in that The hydrophobic modifier is one or more selected from ethyl bromide, ethyl iodide, propyl bromide, propyl iodide, butyl bromide, butyl iodide, benzyl bromide or benzyl iodide; The mass percentage of the hydrophobic modifier is 0.05 to 0.1 mass % based on the calcium magnesium composite oxide.

4. The catalyst according to claim 1, characterized in that The contact angle of the catalyst for preparing methyl formate by alcoholysis of amide compounds is 100 to 180°, preferably 140 to 180°.

5. A method for preparing the catalyst according to any one of claims 1 to 4, characterized in that: The calcium-magnesium composite oxide is dispersed in a solution containing a hydrophobic modifier, stirred at a certain temperature for hydrophobic modification, and after solid-liquid separation, the modified solid is vacuum dried to obtain a catalyst for preparing methyl formate by alcoholysis of amide compounds; The solvent used for the solution containing the hydrophobic modifier is one or more selected from methanol, ethanol or acetone, the temperature of hydrophobic modification is 20-70°C, the time of hydrophobic modification is 1-6h, and when the modified solid is dried, the drying temperature is 50-100°C, and the drying time is 3-6h.

6. The preparation method according to claim 5, characterized in that: The calcium-magnesium composite oxide is prepared by at least one of a hydrothermal method, a coprecipitation method, a sol-gel method and a microemulsion method.

7. The preparation method according to claim 6, characterized in that: A calcium precursor and a magnesium precursor are prepared into a mixed aqueous solution, and then an excess of ammonium carbonate precipitant is added to the mixed aqueous solution at room temperature, or the mixed aqueous solution and the ammonium carbonate precipitant are respectively dripped into a precipitation tank for co-precipitation by a parallel flow co-precipitation method; after the precipitation is completed, the mixture is allowed to stand for aging, and a white precipitate is obtained after filtering, washing and drying, and the white precipitate is roasted to obtain a calcium-magnesium composite oxide.

8. The preparation method according to claim 7, characterized in that: The calcium precursor and the magnesium precursor are independently selected from one or more of calcium and magnesium acetates, nitrates and chlorides; the molar ratio of calcium to magnesium is 0.1 to 10:1, preferably 0.5 to 8:1; the coprecipitation time is 1 to 6 hours; the calcination temperature is 800 to 1000°C; and the calcination time is 3 to 6 hours.

9. A method for using the catalyst according to any one of claims 1 to 4, comprising: In a kettle reactor, an amide compound is dissolved in alcohol, a protective gas of a certain pressure is introduced, and the reaction is carried out under alcoholysis reaction conditions under the action of a catalyst for preparing methyl formate by alcoholysis of the amide compound to obtain an organic amine compound and an ester compound; the alcoholysis reaction conditions are: a reaction temperature of 50 to 150° C., an initial reaction pressure of 0.1 to 6 bar, and a reaction time of 1 to 12 hours.

10. The application method according to claim 9, characterized in that: The amide compound is selected from one or more of N-formylmorpholine, N-methylformamide, N,N-dimethylformamide, N-isobutylformamide, and N-cyclohexylformamide; The alcohol is methanol.

11. The application method according to claim 9, characterized in that: The ratio of the amide compound to the alcohol is 1 mol:100L to 1 mol:5L, preferably 1 mol:50L to 1 mol:20L; The ratio of the amide compound to the catalyst for preparing methyl formate by alcoholysis of the amide compound is 1 mol:200 g to 1 mol:10 g, preferably 1 mol:120 g to 1 mol:80 g.

12. The application method according to claim 9, characterized in that: The alcoholysis reaction conditions are: reaction temperature 60-90°C, initial reaction pressure 1-5 bar, reaction time 4-8 hours; The protective gas is selected from one or more of nitrogen, argon, helium and hydrogen.

Images