CN112206820A

CN112206820A - Composite metal oxide catalyst for preparing isobutyl isobutyrate by using isobutyraldehyde one-step method and preparation method thereof

Info

Publication number: CN112206820A
Application number: CN202011059503.8A
Authority: CN
Inventors: 卢小松; 宋文国; 张世元
Original assignee: Runtai Chemical Taixing Co ltd
Current assignee: Runtai Chemical Taixing Co ltd
Priority date: 2020-09-30
Filing date: 2020-09-30
Publication date: 2021-01-12
Anticipated expiration: 2040-09-30
Also published as: CN112206820B

Abstract

The invention belongs to the technical field of catalysts, and particularly relates to a method for preparing isobutyric acid by using isobutyraldehyde in one stepIsobutyl ester composite metal oxide catalyst and its preparation. Carbon black is used as an inert substrate, and a space synthesis method is combined with a hydrothermal microwave method to synthesize the nano CuO-M with the mesoporous structure_xO_y(M ═ Ce, Cr, and Ti) support, and a supercritical fluid impregnation method was used to support an aluminum iso-butoxide on the surface of the support to prepare a catalyst. The preparation method is simple, the catalyst has a good structure and a good surface distribution state, the mesoporous structure remarkably improves the stability of the catalyst, prolongs the service life of the catalyst, and enables the catalyst to have a higher specific surface area.

Description

Composite metal oxide catalyst for preparing isobutyl isobutyrate by using isobutyraldehyde one-step method and preparation method thereof

Technical Field

The invention belongs to the technical field of catalysts, and particularly relates to a composite metal oxide catalyst for preparing isobutyl isobutyrate by using an isobutyraldehyde one-step method and a preparation method thereof.

Background

Isobutyl isobutyrate (IBIBIBE) is a colorless or light yellow liquid, has pineapple, grape skin or ether fragrance, is a good green product because the isobutyl isobutyrate is basically harmless to human and livestock and does not cause environmental pollution, is widely used as pineapple essence in food, beverage and perfume industries, and is also an excellent organic solvent, a dry paint remover and an extractive distillation additive. With the improvement of environmental protection requirements, isobutyl isobutyrate is more and more widely applied. Isobutyl isobutyrate is generally synthesized by fischer-tropsch esterification of isobutyric acid (IBAC) and Isobutanol (IBOH), which is a traditional process using sulfuric acid as an acid catalyst, and has problems such as low reaction conversion, many byproducts, severe corrosion of equipment, and acidic waste discharge.

Isobutyl isobutyrate is prepared by one step of Tishchenko condensation reaction of isobutyraldehyde, the raw material is single, and the method is a molecular economic reaction. The petrochemical research institute of Heilongjiang province used isobutoxy aluminum as a catalyst, and isobutyl isobutyrate was prepared by one-step reaction of isobutyraldehyde, but the isobutoxy aluminum catalyst is not stable, and is inactivated after reaction due to the fact that a ligand of the catalyst is easily replaced by hydroxyl in the reaction process, and cannot be recycled. These problems have prompted the search for alternative catalysts that combine aluminum isobutoxide with improved long-term stability.

Disclosure of Invention

The invention provides a composite metal oxide catalyst for preparing isobutyl isobutyrate by using isobutyraldehyde through a one-step method, a preparation method and application thereof. Aiming at the problems that the isobutoxy aluminum catalyst is unstable, and the ligand of the catalyst is easy to be substituted by hydroxyl to inactivate in the reaction process, and the like, the mesoporous aluminum catalyst is synthesized by combining a space synthesis method with a hydrothermal microwave methodStructured nano CuO-M_xO_yAnd (M ═ Ce, Cr and Ti) carriers, and isobutylaluminum alkoxide is loaded on the surfaces of the carriers by using a supercritical fluid impregnation method, so that the catalyst has more active centers and stronger adsorption and mass transfer capacities, the stability and the service life of the catalyst are obviously improved, and the catalyst can be recycled for multiple times. The method is used for the reaction of preparing isobutyl isobutyrate from isobutyraldehyde in one step, and can obviously improve the reactivity of the catalyst and the selectivity of methacrylic acid.

The specific preparation method of the composite metal oxide catalyst for preparing isobutyl isobutyrate by using isobutyraldehyde through one-step method is as follows:

(1) dissolving copper nitrate and nitrate of M in water to prepare a metal salt mixed solution; dispersing the pretreated carbon black in an alkali solution of TPAOH, dropwise adding the prepared metal salt mixed solution into the alkali solution, and stirring for 5-6 hours at room temperature; then adding the triblock copolymer F127, and dropwise adding an ammonium hydroxide solution into the triblock copolymer F127 under the stirring condition until the pH value is about 10 (about 9-12); then placing the mixture into a high-pressure kettle, and crystallizing the mixture for 5 to 6 hours in a microwave system at 160 to 180 ℃; then filtering the product, fully washing the product with distilled deionized water, drying the product, and finally calcining the product in a muffle furnace to obtain CuO-M_xO_yThe carrier, wherein the element M is one of Ce, Cr and Ti;

(2) based on a supercritical fluid impregnation method, loading aluminum iso-butoxide on the CuO-M prepared in the step (1)_xO_yAnd (3) washing and drying the surface of the carrier to obtain the composite metal oxide catalyst for preparing isobutyl isobutyrate by using the isobutyraldehyde one-step method.

Further, in the step (1), the mass ratio of the copper nitrate to the nitrate of M is 1: 1-3: 1, and the adding amount of the carbon black is 30-50% of the total mass of the copper nitrate and the nitrate of M; the adding mass of the F127 is 10-20% of the total mass of the copper nitrate and the nitrate of the M. The purpose of the optimization is to prepare the carrier which has more stable structural morphology and is easier to load aluminum iso-butoxide.

Further, in the step (1), the calcining temperature is 500-600 ℃, and the calcining time is 3-4 hours.

Further, the pretreatment method of the carbon black in the step (1) comprises the following steps: the carbon black after drying treatment is dipped by ethanol, and then the ethanol is distilled off.

Further, the aluminum iso-butoxide in the step (2) is prepared by the following method: adding isobutanol and metal aluminum into a reaction container with a reflux condensing device, wherein a drying device of anhydrous calcium chloride is arranged at the top of the reflux condensing device, stirring and refluxing at constant temperature until no gas is discharged, and stopping reaction to obtain the isobutanol aluminum; wherein the mass ratio of the metal aluminum to the isobutanol is 1: 10-1: 5, and the reaction temperature is 120 +/-5 ℃.

Further, the mass of the added aluminum iso-butoxide in the step (2) is CuO-M_xO_y10-50% of the mass of the carrier.

Further, the specific operation method in the step (2) comprises the following steps: adding aluminum iso-butoxide to the CuO-M prepared in step (1)_xO_yPutting the open container into an autoclave filled with ethanol in an open container of a carrier, heating to 270 +/-10 ℃, keeping for 3 +/-4 hours under the pressure of 8.27 +/-1 MPa, washing the solid with ethanol, and drying in vacuum to obtain the composite metal oxide catalyst for preparing isobutyl isobutyrate by the one-step method of isobutyraldehyde.

The composite metal oxide catalyst for preparing isobutyl isobutyrate by using isobutyraldehyde through one-step method is prepared by the preparation method of the composite metal oxide catalyst for preparing isobutyl isobutyrate by using isobutyraldehyde through one-step method.

The application of the composite metal oxide catalyst for preparing isobutyl isobutyrate by using isobutyraldehyde through one-step method is used for catalyzing Tishchenko condensation reaction of isobutyraldehyde to prepare isobutyl isobutyrate.

Further, the method comprises the following steps: filling the composite metal oxide catalyst for preparing isobutyl isobutyrate by using a one-step method of isobutyraldehyde in a fixed bed microreactor, introducing nitrogen under normal pressure, raising the temperature to Tishchenko condensation reaction temperature, adding reactant isobutyraldehyde into the reactor to start reaction, and collecting reaction products after the reaction is stable.

Further, the dosage of the composite metal oxide catalyst for preparing isobutyl isobutyrate by using isobutyraldehyde through a one-step method is 0.4-0.8 ml; the Tishchenko condensation reaction temperature is 250-270 ℃, and the contact time of reactants and the catalyst is 2-4 seconds.

Has the advantages that: the invention synthesizes nano CuO-M with a mesoporous structure by taking carbon black as an inert matrix and combining a space synthesis method with a hydrothermal microwave method_xO_yThe (M ═ Ce, Cr and Ti) carrier, so the catalyst has more active centers, stronger adsorption and mass transfer capability and better surface distribution state. The copper-based catalyst has the advantages of high activity, few byproducts, mild use conditions and the like, and the reaction activity of the copper-based catalyst is further improved by compounding Cu with metal oxides of Ce, Cr, Ti and the like. And the supercritical fluid impregnation method is utilized to load the aluminum iso-butoxide on the surface of the carrier, the loading amount of the active component is high, the distribution of the active component on the carrier is uniform, the binding force between the carrier and the active component is stronger, the stability of the catalyst is obviously improved, the service life of the catalyst is obviously prolonged, and the catalyst can be recycled for multiple times. The method is used for the reaction of preparing isobutyl isobutyrate from isobutyraldehyde in one step, and higher yield and conversion rate are obtained through experiments.

Detailed Description

The present invention is further described below with reference to examples, but is not limited thereto.

Example 1

(1) Preparation of the support

9.0g of copper nitrate and 3.0g of cerium nitrate were weighed, and dissolved in 120 ml of water after being mixed uniformly to prepare a metal salt mixed solution. Drying 3.6g of carbon black at 150 ℃ for 24h, then fully soaking the carbon black with ethanol, using the ethanol after the ethanol is evaporated, and carrying out surface active treatment on the carbon black to enhance the adsorption capacity of the carbon black. Then, the carbon black after the pretreatment was dispersed in an alkali solution having a concentration of 0.1mol/L TPAOH, and the prepared metal salt mixed solution was added dropwise thereto and stirred at room temperature for 5 hours. 1.2g F127 was added thereto, and 2mol/L ammonium hydroxide solution was added dropwise thereto with stirring until the pH was 10. Then, the mixture was placed in an autoclave and crystallized at 180 ℃ for 6 hours in a microwave system. Then filtering the product, washing the product for a plurality of times by distilled deionized water, and drying the product in a drying oven at 80 DEG CAnd (5) 24 h. Finally calcining the mixture for 4 hours at the high temperature of 600 ℃ in a muffle furnace to obtain CuO-CeO₂And (3) a carrier.

(2) Preparation of aluminium iso-butoxide

Adding 10.0g of metal aluminum and 60g of isobutanol into a three-neck flask, connecting a drying device filled with anhydrous calcium chloride at the top end of a reflux condensation tube, stirring, heating and refluxing at 120 ℃ until no gas is discharged, and stopping reaction to obtain the aluminum iso-butoxide.

(3) Preparation of composite metal oxide catalyst for preparing isobutyl isobutyrate by using isobutyraldehyde one-step method

3.0g of CuO-CeO was weighed₂The carrier and 0.3g of aluminum iso-butoxide are added into a flask, the flask is placed into an autoclave filled with ethanol, the temperature is increased to 270 ℃, the ethanol enters the flask in a steam state and is kept for 3 hours under the pressure of 8.27MPa, the solid is washed by the ethanol and is dried for 12 hours in a vacuum drying oven, and the composite metal oxide catalyst for preparing iso-butyl isobutyrate by the isobutyraldehyde one-step method is obtained.

(4) Reaction for preparing isobutyl isobutyrate from isobutyraldehyde in one step

And (3) weighing 0.6ml of the composite metal oxide catalyst prepared in the step (3) and used for preparing isobutyl isobutyrate by the one-step method of isobutyraldehyde, filling the composite metal oxide catalyst into a fixed bed microreactor, filling the place where the catalyst is not filled with quartz sand, and plugging two ends of a reaction tube by using a small amount of quartz wool. Under normal pressure, nitrogen is introduced, the reaction temperature is increased to 270 ℃, then reactant isobutyraldehyde is added into the reactor to start reaction, and the contact time of the reactant and the catalyst is 2 seconds. After the reaction was stabilized, the reaction product was collected and analyzed by gas chromatography equipped with FID and TCD detectors.

Example 2

The procedure of example 1 was otherwise the same as that of example 3 except that 0.3g of aluminum isobutylalkoxide in step (3) was changed to 0.6g of aluminum isobutylalkoxide.

Example 3

The procedure of example 1 was otherwise the same as that of example 3 except that 0.3g of aluminum isobutylalkoxide in step (3) was changed to 0.9g of aluminum isobutylalkoxide.

Example 4

The procedure of example 1 was otherwise the same as that of example 1 except that 0.3g of aluminum isobutylalkoxide in step (3) was changed to 1.2g of aluminum isobutylalkoxide.

Example 5

The procedure of example 1 was otherwise the same as that of example 1 except that 0.3g of aluminum isobutylalkoxide in step (3) was changed to 1.5g of aluminum isobutylalkoxide.

Example 6

The reaction temperature in the step (4) was changed to 260 ℃ and the other operations were the same as in example 1.

Example 7

The reaction temperature in the step (4) was changed to 250 ℃ and the other operations were the same as in example 1.

Example 8

The contact time in the step (4) was changed to 4 seconds, and the other operations were the same as in example 1.

Example 9

9.0g of copper nitrate and 3.0g of chromium nitrate were weighed and dissolved in 120 ml of water after being mixed uniformly to prepare a metal salt mixed solution, and the other operations were the same as in example 1.

Example 10

9.0g of copper nitrate and 3.0g of titanium nitrate were weighed, and dissolved in 120 ml of water after being mixed uniformly to prepare a metal salt mixed solution. The other operations were the same as in example 1.

Example 11

9.0g of copper nitrate and 6.0g of cerium nitrate were weighed and mixed uniformly, and a metal salt mixed solution was prepared in the same manner as in example 1 except that the operation was changed.

Example 12

9.0g of copper nitrate and 9.0g of cerium nitrate were weighed and mixed uniformly, and a metal salt mixed solution was prepared in the same manner as in example 1 except that the operation was changed.

Example 13

The calcination temperature in step (1) was changed to 550 ℃ and the operation was otherwise the same as in example 1.

Example 14

The calcination temperature in the step (1) was changed to 500 ℃ and the other operations were the same as in example 1.

Example 15

The calcination time in step (1) was changed to 3 hours, and the other operations were the same as in example 1.

Example 16

The same procedure as in example 1 was repeated except that 3.6g of carbon black in step (1) was changed to 4.8g of carbon black.

Example 17

The same procedure as in example 1 was repeated except that 3.6g of carbon black in step (1) was changed to 6.0g of carbon black.

Comparative example 1

9.0g of copper nitrate was weighed and dissolved in 120 ml of water to prepare a metal salt solution. 3.6g of carbon black is dried at 150 ℃ for 24h and then the carbon black is fully impregnated with ethanol, and the ethanol is used after evaporation. Then, the carbon black after the pretreatment was dispersed in an alkali solution having a concentration of 0.1mol/L TPAOH, and the prepared metal salt solution was added dropwise thereto and stirred at room temperature for 5 hours. 1.2g F127 was added thereto, and 2mol/L ammonium hydroxide solution was added dropwise thereto with stirring until the pH was 10. Then, the mixture was placed in an autoclave and crystallized at 180 ℃ for 6 hours in a microwave system. The product was then filtered, washed several times with distilled deionized water and dried in an oven at 80 ℃ for 24 h. And finally calcining the mixture for 4 hours at the high temperature of 600 ℃ in a muffle furnace to obtain the carrier. The other operations were the same as in example 1.

Comparative example 2

No carbon black was added.

9.0g of copper nitrate and 3.0g of cerium nitrate were weighed and dissolved in 120 ml of water after being mixed well. The prepared metal salt mixed solution was added dropwise to a 0.1mol/L alkali solution of TPAOH, and stirred at room temperature for 5 hours. 1.2g F127 was added thereto, and 2mol/L ammonium hydroxide solution was added dropwise thereto with stirring until the pH was 10. Then, the mixture was placed in an autoclave and crystallized at 180 ℃ for 6 hours in a microwave system. The product was then filtered, washed several times with distilled deionized water and dried in an oven at 80 ℃ for 24 h. And finally calcining the mixture for 4 hours at the high temperature of 600 ℃ in a muffle furnace to obtain the carrier. The other operations were the same as in example 1.

Comparative example 3

The reaction was carried out in the same manner as in example 1 except that aluminum isopropoxide was used as a catalyst.

0.6ml of aluminum iso-butoxide was weighed and charged in a fixed bed microreactor. The place where the catalyst is not filled is filled with quartz sand, and a small amount of quartz wool is used for plugging the two ends of the reaction tube. Under normal pressure, nitrogen is introduced, the reaction temperature is increased to 270 ℃, then reactant isobutyraldehyde is added into the reactor to start reaction, and the contact time of the reactant and the catalyst is 2 seconds. After the reaction was stabilized, the reaction product was collected and analyzed by gas chromatography equipped with FID and TCD detectors.

Comparative example 4

Without the use of a microwave system. The other operations were the same as in example 1.

9.0g of copper nitrate and 3.0g of cerium nitrate were weighed and dissolved in 120 ml of water after being mixed well. The prepared metal salt mixed solution was added dropwise to a 0.1mol/L alkali solution of TPAOH, and stirred at room temperature for 5 hours. 1.2g F127 was added thereto, and 2mol/L ammonium hydroxide solution was added dropwise thereto with stirring until the pH was 10. Then the mixture is placed in an autoclave and crystallized for 6 hours in an oven at 180 ℃. The product was then filtered, washed several times with distilled deionized water and dried in an oven at 80 ℃ for 24 h. And finally calcining the mixture for 4 hours at the high temperature of 600 ℃ in a muffle furnace to obtain the carrier.

Comparative example 5

The supercritical load is changed to be loaded by a conventional method.

3.0g of the carrier was weighed into 25ml of distilled deionized water and stirred for 10 minutes. 0.3g of aluminum iso-butoxide was then weighed out and dissolved in 25ml of distilled deionized water, and the solution was gradually added dropwise to the suspension of the support and stirred for 6 hours. Then dried in a vacuum drying oven for 12 hours to obtain the catalyst.

The performance of the catalysts obtained in the respective examples and comparative examples is shown in Table 1.

TABLE 1

The catalyst performance data for the catalysts obtained in example 1 and comparative example were repeated 5 times and are shown in table 2.

TABLE 2

The catalyst prepared by the invention is prepared by combining a space synthesis method with a hydrothermal microwave method to synthesize nano CuO-M with a mesoporous structure_xO_yThe (M ═ Ce, Cr and Ti) carrier, so the catalyst has more active centers, stronger adsorption and mass transfer capability and better surface distribution state. The copper-based catalyst has the advantages of high activity, few byproducts, mild use conditions and the like, and the reaction activity of the copper-based catalyst is further improved by compounding Cu with metal oxides of Ce, Cr, Ti and the like. And then loading the isobutylaluminum alcoholate on the surface of the carrier by utilizing a supercritical fluid impregnation method, wherein the loading amount of the active component is high, the distribution of the active component on the carrier is uniform, the binding force between the carrier and the active component is stronger, the stability of the catalyst is further improved, the catalyst can be recycled for multiple times, the defects that the isobutylaluminum oxide catalyst is not stable to a great extent, and the conversion rate of isobutyraldehyde and the selectivity of methacrylic acid are remarkably improved because the ligand of the catalyst is easily replaced by hydroxyl in the reaction process, and is inactivated after reaction and cannot be recycled for multiple times and the like are overcome. In addition, the catalyst prepared by the invention is an environment-friendly catalyst and has good industrial application prospect.

Claims

1. The preparation method of the composite metal oxide catalyst for preparing isobutyl isobutyrate by using isobutyraldehyde through one-step method is characterized by comprising the following steps:

(1) dissolving copper nitrate and nitrate of M in water to prepare a metal salt mixed solution; dispersing the pretreated carbon black in an alkali solution of TPAOH, dropwise adding the prepared metal salt mixed solution into the alkali solution, and stirring for 5-6 hours at room temperature; then adding the triblock copolymer F127, and dropwise adding an ammonium hydroxide solution into the triblock copolymer F127 under the stirring condition until the pH value is 9-12; then placing the mixture into a high-pressure kettle, and crystallizing the mixture for 5 to 6 hours in a microwave system at 160 to 180 ℃; then filtering the product, fully washing the product with distilled deionized water, drying the product, and finally calcining the product in a muffle furnace to obtain CuO-M_xO_yA carrier, wherein the element M isCe. One of Cr and Ti;

2. The method for preparing a composite metal oxide catalyst for preparing isobutyl isobutyrate by a one-step method of isobutyraldehyde according to claim 1, wherein the mass ratio of the copper nitrate to the nitrate of M in the step (1) is 1:1 to 3:1, and the amount of carbon black added is 30 to 50% of the total mass of the copper nitrate and the nitrate of M; the adding mass of the F127 is 10-20% of the total mass of the copper nitrate and the nitrate of the M.

3. The method for preparing a composite metal oxide catalyst for preparing isobutyl isobutyrate by a one-step method of isobutyraldehyde according to claim 1, wherein the calcination temperature in the step (1) is 500 to 600 ℃, and the calcination time is 3 to 4 hours;

and/or the pretreatment method of the carbon black in the step (1) comprises the following steps: the carbon black after drying treatment is dipped by ethanol, and then the ethanol is distilled off.

4. The method of preparing a composite metal oxide catalyst for the one-step preparation of isobutyl isobutyrate from isobutyraldehyde according to claim 1, wherein the aluminum isobutyrate in the step (2) is prepared by: adding isobutanol and metal aluminum into a reaction container with a reflux condensing device, wherein a drying device of anhydrous calcium chloride is arranged at the top of the reflux condensing device, stirring and refluxing at constant temperature until no gas is discharged, and stopping reaction to obtain the isobutanol aluminum; wherein the mass ratio of the metal aluminum to the isobutanol is 1: 10-1: 5, and the reaction temperature is 120 +/-5 ℃.

5. The method of preparing a complex metal oxide catalyst for the one-step preparation of isobutyl isobutyrate from isobutyraldehyde according to claim 1, wherein the mass of aluminum isobutyrate added in the step (2) is CuO-M_xO_y10-50% of the mass of the carrier.

6. The method for preparing a composite metal oxide catalyst for the one-step preparation of isobutyl isobutyrate from isobutyraldehyde according to claim 1, wherein the specific operation method in the step (2) comprises the steps of: adding aluminum iso-butoxide to the CuO-M prepared in step (1)_xO_yPutting the open container into an autoclave filled with ethanol in an open container of a carrier, heating to 270 +/-10 ℃, keeping for 3 +/-4 hours under the pressure of 8.27 +/-1 MPa, washing the solid with ethanol, and drying in vacuum to obtain the composite metal oxide catalyst for preparing isobutyl isobutyrate by the one-step method of isobutyraldehyde.

7. A composite metal oxide catalyst for one-step preparation of isobutyl isobutyrate from isobutyraldehyde, which is prepared by the method of any one of claims 1 to 6.

8. The use of the composite metal oxide catalyst for preparing isobutyl isobutyrate by the one-step method of isobutyraldehyde according to claim 7, wherein the composite metal oxide catalyst is used for catalyzing Tishchenko condensation reaction of isobutyraldehyde to prepare isobutyl isobutyrate.

9. The use of the composite metal oxide catalyst in a one-step process for preparing isobutyl isobutyrate from isobutyraldehyde according to claim 8, wherein: the method comprises the following steps: filling the composite metal oxide catalyst for preparing isobutyl isobutyrate by using a one-step method of isobutyraldehyde in a fixed bed microreactor, introducing nitrogen under normal pressure, raising the temperature to Tishchenko condensation reaction temperature, adding reactant isobutyraldehyde into the reactor to start reaction, and collecting reaction products after the reaction is stable.

10. The use of the composite metal oxide catalyst for one-step preparation of isobutyl isobutyrate from isobutyraldehyde according to claim 9, wherein the amount of the composite metal oxide catalyst for one-step preparation of isobutyl isobutyrate from isobutyraldehyde is 0.4-0.8 ml; the Tishchenko condensation reaction temperature is 250-270 ℃, and the contact time of reactants and the catalyst is 2-4 seconds.