A lanthanum phosphite supported zirconia catalyst, its preparation method and application

Abstract

A lanthanum phosphite supported zirconia catalyst, its preparation method and application relate to the field of catalysts. The preparation method comprises the following steps: S1: adding a phosphite compound into an organic solvent, stirring to obtain a mixed solution I; S2: adding an aqueous lanthanum salt solution into the mixed solution I, and then heating to boiling to obtain a mixed solution II; S3: adding an aqueous zirconium salt solution and an aqueous urea solution into the mixed solution II, and then heating to 80°C - 100°C to obtain a mixed solution III; S4: cooling the mixed solution III, and then successively performing suction filtration, washing with water, pressure filtration, drying, and calcination to obtain the lanthanum phosphite supported zirconia catalyst. The lanthanum phosphite supported zirconia catalyst of the present invention can catalyze the reaction of glyoxylate and o-methoxyphenol to synthesize 2-hydroxy-2-(4-hydroxy-3-methoxyphenyl) acetate.

Description

Technical Field

[0001] The present invention relates to the field of catalysts, and more specifically to a lanthanum phosphite supported zirconia catalyst, a preparation method thereof, and an application thereof. Background Art

[0002] Vanillin is the synthetic edible flavor with the largest output in the world, and is applied to various foods, tobaccos, cosmetics, and daily necessities, and can also be used in medicine. At present, with the development of the economy, the consumption of flavors increases year by year, and the global market demand for vanillin is more than 20,000 tons. As an important intermediate for synthesizing vanillin, the demand for 2-hydroxy-2-(4-hydroxy-3-methoxyphenyl) acetate is also increasing day by day.

[0003] However, there is no mature preparation method for 2-hydroxy-2-(4-hydroxy-3-methoxyphenyl) acetate in the prior art. Summary of the Invention

[0004] The present invention aims to provide a lanthanum phosphite supported zirconia catalyst, a preparation method thereof, and an application thereof, so as to synthesize 2-hydroxy-2-(4-hydroxy-3-methoxyphenyl) acetate by catalyzing the reaction of glyoxylate and o-methoxyphenol.

[0005] To solve the above technical problems, the specific solution adopted by the present invention is as follows: A preparation method of a lanthanum phosphite supported zirconia catalyst, comprising the following steps:

[0006] S1: Add a phosphite compound to an organic solvent, stir to obtain a mixed solution I;

[0007] S2: Add an aqueous solution of lanthanum salt to the mixed solution I, and then heat to boiling to obtain a mixed solution II;

[0008] S3: Add an aqueous solution of zirconium salt and an aqueous solution of urea to the mixed solution II, and then heat to 80°C to 100°C to obtain a mixed solution III;

[0009] S4: Cool the mixed solution III, and then successively carry out suction filtration, water washing, pressure filtration, drying, and calcination to obtain the lanthanum phosphite supported zirconia catalyst.

[0010] As a further optimization of the above technical solution, the phosphite compound is phosphite, methyl phosphite, or ethyl phosphite.

[0011] As a further optimization of the above technical solution, the lanthanum salt is lanthanum nitrate, lanthanum sulfate, or lanthanum chloride.

[0012] As a further optimization of the above technical solution, the zirconium salt is zirconium nitrate, zirconium sulfate, or zirconium chloride.

[0013] As a further optimization of the above technical solution, the content of lanthanum salt in the lanthanum salt aqueous solution is less than 50%; the content of zirconium salt in the zirconium salt aqueous solution is less than 10%, and the content of urea in the urea aqueous solution is less than 50%.

[0014] As a further optimization of the above technical solution, after heating to boiling in step S2, keep boiling for 0 - 24 h to obtain the mixed solution II; after heating to 80°C - 100°C in step S3, keep the temperature constant for 0 - 24 h to obtain the mixed solution III.

[0015] A lanthanum phosphite supported zirconia catalyst prepared according to the above method.

[0016] An application of a lanthanum phosphite supported zirconia catalyst in the synthesis of 2-hydroxy-2-(4-hydroxy-3-methoxyphenyl) acetate. The lanthanum phosphite supported zirconia catalyst synthesizes 2-hydroxy-2-(4-hydroxy-3-methoxyphenyl) acetate by catalyzing the reaction of glyoxylate with o-methoxyphenol.

[0017] As a further optimization of the above technical solution, first, load the lanthanum phosphite supported zirconia catalyst into a fixed bed reactor. The reaction raw material in the fixed bed reactor is a toluene solution containing 10% methyl glyoxylate and 20% o-methoxyphenol. The feed rate of the reaction raw material is 0.25 mL / min, and the gasification temperature is 220°C.

[0018] As a further optimization of the above technical solution, both the upper and lower parts of the fixed bed reactor are sealed with quartz sand. The lanthanum phosphite supported zirconia catalyst catalyzes the reaction of glyoxylate with o-methoxyphenol under the conditions of normal pressure, a high-purity nitrogen flow rate of 300 mL / min, and a reaction temperature of 230°C.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention uses lanthanum phosphite as a carrier to prepare a catalyst with highly dispersed nano-zirconia loaded on the surface of the carrier, which is used to catalyze the reaction of glyoxylate with o-methoxyphenol to synthesize 2-hydroxy-2-(4-hydroxy-3-methoxyphenyl) acetate, and obtains a good catalytic effect.

[0020] Zirconia is evenly distributed on the surface of lanthanum phosphite, increasing the acid sites and enhancing the acid strength on the surface of lanthanum phosphite. At the same time, affected by the hydroxyl group on the benzene ring, the ortho and para positions of the hydroxyl group are activated and can undergo a condensation reaction with carbonyl compounds. Under acid catalysis, o-methoxyphenol becomes o-methoxyphenoxide anion, which has stronger nucleophilicity. Under certain conditions, glyoxylate undergoes a condensation reaction with the para position of o-methoxyphenol to obtain the target product 2-hydroxy-2-(4-hydroxy-3-methoxyphenyl) acetate.

[0021] The chemical reaction structural formula is as follows:

[0022] Detailed implementation manners

[0023] The technical solution of the present invention will be further elaborated in detail below. For parts that are not detailedly described and disclosed in the following embodiments of the present invention, they should all be understood as the prior art known or should be known to those skilled in the art.

[0024] The present invention discloses a preparation method of a lanthanum phosphite supported zirconia catalyst, comprising the following steps:

[0025] S1: Add a phosphite compound into an organic solvent, stir to obtain a mixed solution I;

[0026] Among them, the phosphite compound is phosphite, methyl phosphite or ethyl phosphite, and the organic solvent is an alcohol solvent such as methanol or ethanol, and the stirring time is 0 - 120 min.

[0027] S2: Add an aqueous lanthanum salt solution into the mixed solution I, and then heat it to boiling to obtain a mixed solution II;

[0028] The lanthanum salt is lanthanum nitrate, lanthanum sulfate or lanthanum chloride. The content of the lanthanum salt in the aqueous lanthanum salt solution is less than 50%. After adding, heat it to the boiling of the mixed solution, and keep boiling for 0 - 24 h.

[0029] S3: Add an aqueous zirconium salt solution and an aqueous urea solution into the mixed solution II, and then heat it to 80°C - 100°C to obtain a mixed solution III;

[0030] Specifically, add the aqueous zirconium salt solution and the aqueous urea solution to the boiling mixed solution II in step S2. The zirconium salt added is zirconium nitrate, zirconium sulfate or zirconium chloride. The content of the zirconium salt in the aqueous zirconium salt solution is less than 10%, and the content of urea in the aqueous urea solution is less than 50%. After adding, the temperature of the mixed solution drops, and then continue to heat the mixed solution after adding the aqueous zirconium salt solution and the aqueous urea solution to 80°C - 100°C, and keep it at a constant temperature for 0 - 24 h to obtain a mixed solution III.

[0031] S4: Cool the mixed solution III, and then successively carry out suction filtration, washing with water, pressure filtration, drying, and calcination to obtain the lanthanum phosphite supported zirconia catalyst.

[0032] The present invention also discloses an application of a lanthanum phosphite supported zirconia catalyst, which is used to catalyze the synthesis of 2 - hydroxy - 2-(4 - hydroxy - 3 - methoxyphenyl) acetate from glyoxylate and o - methoxyphenol. Among them, the glyoxylate is methyl glyoxylate, ethyl glyoxylate or butyl glyoxylate, etc.

[0033] Specific operation: Take 1 - 20 mL of lanthanum phosphite supported zirconia catalyst with a particle size of 60 - 10 mesh, fill it in the middle of a fixed - bed reactor, and seal it with quartz sand at both ends. React under the conditions of a pressure of 1 - 3 MPa, a gas flow rate of less than 2000 mL / min, and a temperature of 80 - 300 °C. After the reaction solution is cooled, it is collected and analyzed by liquid chromatography.

[0034] The following further illustrates the present invention in conjunction with specific embodiments.

[0035] Example 1

[0036] Preparation of lanthanum phosphite supported zirconia catalyst:

[0037] S1: Take 48 g of dimethyl phosphite and add it to 4.5 L of methanol, stir for 10 min to obtain a mixed solution Ⅰ.

[0038] S2: Dropwise add 500 mL of an aqueous solution containing 186.5 g of lanthanum nitrate hexahydrate to the mixed solution Ⅰ within 2 h. After the addition is completed, raise the temperature to the boiling point of the mixed solution and keep boiling for 8 h to obtain a mixed solution Ⅱ.

[0039] S3: After the mixed solution Ⅱ is kept at a constant temperature, add 3.5 L of a mixed aqueous solution containing 17.5 g of zirconium nitrate pentahydrate and 10 g of urea, continue to raise the temperature, raise the temperature of the mixed solution to 95 - 100 °C, and keep it at a constant temperature for 12 h to obtain a mixed solution Ⅲ.

[0040] S4: After the mixed solution Ⅲ is naturally cooled to below 60 °C, pour the mixture into a Buchner funnel, filter while washing with deionized water until the conductivity is lower than 1000 us / cm. Then filter the filter cake in a filter press, dry it at 120 °C for 12 h, and finally calcine it in a muffle furnace at 400 °C in an air atmosphere for 4 h to obtain the finished product of lanthanum phosphite supported zirconia catalyst, denoted as catalyst Ⅰ.

[0041] Application of lanthanum phosphite supported zirconia catalyst:

[0042] Crush catalyst Ⅰ to 10 - 20 mesh, then take 10 mL and fill it in the middle of a DN14mmH400mm fixed - bed reactor, and seal it with 20 mL of quartz sand at both ends. The catalyst reacts under the conditions of normal pressure, a high - purity nitrogen flow rate of 300 mL / min, and a reaction temperature of 230 °C.

[0043] Feeding conditions: Feed rate 0.25 mL / min (toluene solution containing 10% methyl glyoxylate and 20% o - methoxyphenol), vaporization temperature 220 °C.

[0044] The reaction solution is analyzed by liquid chromatography. The conversion rate of methyl glyoxylate is 83.6%, and the selectivity of the target product methyl 2 - hydroxy - 2-(4 - hydroxy - 3 - methoxyphenyl)acetate is 64.7%.

[0045] Example 2

[0046] Preparation of lanthanum phosphite supported zirconium dioxide:

[0047] S1: 59.5 g of diethyl phosphite was added to 4.5 L of ethanol and stirred for 10 min to prepare a mixed solution I;

[0048] S2: Add 500 mL of an aqueous solution containing 186.5 g of lanthanum nitrate hexahydrate to the mixed solution I dropwise within 2 h. After the addition is complete, heat the mixed solution to boiling and maintain the boiling temperature for 8 h to obtain a mixed solution II.

[0049] S3: After maintaining the temperature, add 3.5 L of a mixed aqueous solution containing 17.5 g of zirconium nitrate pentahydrate and 10 g of urea to the mixed solution II, continue heating the mixed solution to 95°C to 100°C, and maintain the temperature for 12 hours to obtain a mixed solution III;

[0050] S4: After the mixed solution III is naturally cooled to below 60°C, the mixture is poured into a Buchner funnel and washed with deionized water while filtering until the conductivity is lower than 1000us / cm. The filter cake is then filtered in a filter press and dried at 120°C for 12 hours. Finally, it is placed in a muffle furnace and calcined at 400°C for 4 hours in an air atmosphere to obtain a finished product of lanthanum phosphite-supported zirconium dioxide catalyst, which is recorded as catalyst II.

[0051] Application of lanthanum phosphite supported zirconium dioxide catalyst:

[0052] Catalyst II was crushed into 10-20 mesh, and then 10 mL was taken and loaded into the middle of a DN14mmH400mm fixed-bed reactor. The upper and lower parts were sealed with 20 mL of quartz sand. The catalyst was reacted under normal pressure, a high-purity nitrogen flow rate of 300 mL / min, and a reaction temperature of 230°C.

[0053] Feed conditions: feed rate 0.25 mL / min (toluene solution containing 11.6% ethyl glyoxylate and 20% o-methoxyphenol), vaporization temperature 220°C.

[0054] The reaction solution was analyzed by liquid chromatography, and the conversion rate of ethyl glyoxylate was 89.2%, and the selectivity of the target product methyl 2-hydroxy-2-(4-hydroxy-3-methoxyphenyl)acetate was 75.7%.

[0055] Example 3

[0056] Preparation of lanthanum phosphite supported zirconium dioxide:

[0057] S1: 59.5 g of diethyl phosphite was added to 4.5 L of ethanol and stirred for 10 min to prepare a mixed solution I;

[0058] S2: Drop 500 mL of an aqueous solution containing 186.5 g of lanthanum nitrate hexahydrate into the mixed solution Ⅰ within 2 h. After the dropping is completed, raise the temperature to the boiling point of the mixed solution and keep boiling for 8 h to obtain the mixed solution Ⅱ;

[0059] S3: After constant temperature, add 3.5 L of a mixed aqueous solution containing 17.5 g of zirconium nitrate pentahydrate and 10 g of urea to the mixed solution Ⅱ, continue to raise the temperature, and raise the temperature of the mixed solution to 80 °C, then keep the temperature constant for 24 h to obtain the mixed solution Ⅲ;

[0060] S4: After the mixed solution Ⅲ is naturally cooled to below 60 °C, pour the mixture into a Buchner funnel, filter with suction while washing with deionized water until the conductivity is lower than 1000 us / cm, then filter the filter cake in a filter press, dry at 120 °C for 12 h, and finally place it in a muffle furnace and calcine at 400 °C in an air atmosphere for 4 h to obtain the finished product of lanthanum phosphite supported zirconia catalyst.

[0061] Example 4

[0062] Preparation of lanthanum phosphite supported zirconia:

[0063] S1: Take 48 g of dimethyl phosphite and add it to 4.5 L of methanol, stir for 10 min to obtain the mixed solution Ⅰ;

[0064] S2: Drop 500 mL of an aqueous solution containing 186.5 g of lanthanum nitrate hexahydrate into the mixed solution Ⅰ within 2 h. After the dropping is completed, raise the temperature to the boiling point of the mixed solution and keep boiling for 24 h to obtain the mixed solution Ⅱ;

[0065] S3: After the mixed solution Ⅱ is kept at a constant temperature, add 3.5 L of a mixed aqueous solution containing 17.5 g of zirconium nitrate pentahydrate and 10 g of urea, continue to raise the temperature, and raise the temperature of the mixed solution to 95 °C - 100 °C, then keep the temperature constant for 8 h to obtain the mixed solution Ⅲ.

[0066] S4: After the mixed solution Ⅲ is naturally cooled to below 60 °C, pour the mixture into a Buchner funnel, filter with suction while washing with deionized water until the conductivity is lower than 1000 us / cm, then filter the filter cake in a filter press, dry at 120 °C for 12 h, and finally place it in a muffle furnace and calcine at 400 °C in an air atmosphere for 4 h, namely, the finished product of lanthanum phosphite supported zirconia catalyst is prepared.

[0067] Example 5

[0068] Preparation of lanthanum phosphite supported zirconia:

[0069] S1: Take 59.5 g of diethyl phosphite and add it to 4.5 L of ethanol, stir for 10 min to obtain the mixed solution Ⅰ;

[0070] S2: Add 500 mL of an aqueous solution containing 220 g of lanthanum nitrate hexahydrate dropwise to the mixed solution I within 2 h. After the addition is complete, raise the temperature to the boiling point of the mixed solution and keep boiling for 8 h to obtain the mixed solution II;

[0071] S3: After constant temperature, add 3.5 L of a mixed aqueous solution containing 15 g of zirconium nitrate pentahydrate and 8 g of urea to the mixed solution II, and continue to raise the temperature to 95 °C - 100 °C. Keep the temperature constant for 12 h to obtain the mixed solution III;

[0072] S4: After the mixed solution III is naturally cooled to below 60 °C, pour the mixture into a Buchner funnel, filter while washing with deionized water until the conductivity is lower than 1000 us / cm. Then, filter the filter cake in a filter press, dry it at 120 °C for 12 h, and finally calcine it in a muffle furnace at 400 °C for 4 h in an air atmosphere to obtain the finished product of lanthanum phosphite supported zirconia catalyst.

[0073] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A preparation method of a lanthanum phosphite supported zirconia catalyst, characterized in that, It includes the following steps: S1: Add a phosphite compound into an organic solvent and stir to obtain a mixed solution I; S2: Add an aqueous solution of lanthanum salt into the mixed solution I, and then heat it to boiling to obtain a mixed solution II; S3: Add an aqueous solution of zirconium salt and an aqueous solution of urea into the mixed solution II, and then heat it to 80°C - 100°C to obtain a mixed solution III; S4: Cool the mixed solution III, and then successively carry out suction filtration, washing with water, pressure filtration, drying, and calcination to obtain a lanthanum phosphite supported zirconia catalyst.

2. The preparation method of a lanthanum phosphite supported zirconia catalyst according to claim 1, characterized in that, The phosphite compound is phosphite, methyl phosphite, or ethyl phosphite.

3. The preparation method of a lanthanum phosphite supported zirconia catalyst according to claim 1, characterized in that, The lanthanum salt is lanthanum nitrate, lanthanum sulfate, or lanthanum chloride.

4. The preparation method of a lanthanum phosphite supported zirconia catalyst according to claim 1, characterized in that, The zirconium salt is zirconium nitrate, zirconium sulfate, or zirconium chloride.

5. The preparation method of a lanthanum phosphite supported zirconia catalyst according to claim 1, characterized in that, The content of lanthanum salt in the aqueous solution of lanthanum salt is less than 50%; the content of zirconium salt in the aqueous solution of zirconium salt is less than 10%, and the content of urea in the aqueous solution of urea is less than 50%.

6. The preparation method of a lanthanum phosphite supported zirconia catalyst according to claim 1, characterized in that, After heating to boiling in step S2, keep boiling for 0 - 24 h to obtain a mixed solution II; after heating to 80°C - 100°C in step S3, keep the temperature constant for 0 - 24 h to obtain a mixed solution III.

7. A lanthanum phosphite supported zirconia catalyst prepared by the method according to any one of claims 1 - 6.

8. Use of the lanthanum phosphite supported zirconia catalyst as described in claim 7 in the synthesis of 2-hydroxy-2-(4-hydroxy-3-methoxyphenyl) acetate, characterized in that, The lanthanum phosphite supported zirconia catalyst catalyzes the reaction of glyoxylate with o-methoxyphenol to synthesize 2-hydroxy-2-(4-hydroxy-3-methoxyphenyl) acetate.

9. Use of the lanthanum phosphite supported zirconia catalyst according to claim 8 in the synthesis of 2-hydroxy-2-(4-hydroxy-3-methoxyphenyl) acetate, characterized in that, First, load the lanthanum phosphite supported zirconia catalyst into a fixed-bed reactor. The reaction raw materials in the fixed-bed reactor are a toluene solution containing 10% methyl glyoxylate and 20% o-methoxyphenol. The feed rate of the reaction raw materials is 0.25 mL / min, and the gasification temperature is 220°C.

10. Use of the lanthanum phosphite supported zirconia catalyst according to claim 9 in the synthesis of 2-hydroxy-2-(4-hydroxy-3-methoxyphenyl) acetate, characterized in that, Both the upper and lower parts of the fixed-bed reactor are sealed with quartz sand. The lanthanum phosphite supported zirconia catalyst catalyzes the reaction of glyoxylate with o-methoxyphenol under the conditions of normal pressure, a high-purity nitrogen flow rate of 300 mL / min, and a reaction temperature of 230°C.

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