Catalyst for synthesizing neohesperidin dihydrochalcone, preparation method and synthesis method

Abstract

The invention discloses a preparation method of a catalyst for synthesizing neohesperidin dihydrochalcone, which comprises the following steps: 1, cooking activated carbon in a nitric acid solution, filtering and washing to obtain activated carbon subjected to acid treatment; 2, placing the acid-treated activated carbon in a mixed solution of sodium bicarbonate and ammonium thiosulfate, stirring, filtering, and washing to obtain mixed solution treated activated carbon; 3, putting the active carbon treated by the mixed solution into an auxiliary agent solution, stirring, and filtering to obtain auxiliary agent modified active carbon; 4, mixing the auxiliary agent modified activated carbon with the mesoporous silica carrier to obtain a mixed carrier; 5, placing the mixed carrier in an ammonium chloropalladate solution, stirring, filtering, and washing to obtain a catalyst precursor; and 6, reducing the catalyst precursor to obtain the catalyst. When the catalyst prepared by the method is used for synthesizing neohesperidin dihydrochalcone, the yield exceeds 97.0%, and the catalyst has high reaction performance.

Description

Technical Field

[0001] The invention belongs to the technical field of organic synthesis, and particularly relates to a catalyst for synthesizing neohesperidin dihydrochalcone, a preparation method and a synthesis method. Background Art

[0002] Neohesperidin dihydrochalcone has the characteristics of high sweetness (1500-1800 times the sweetness of sucrose), refreshing taste, long-lasting aftertaste, low calories, non-toxicity, good stability, etc. It is currently the most popular new sweetener and bitter masking agent. In the 1970s, the study of the synthesis of neohesperidin dihydrochalcone by catalytic hydrogenation using neohesperidin as raw material began, and then scholars at home and abroad have successively conducted research and reports in this regard. At first, most studies used high temperature and high pressure methods to achieve the synthesis of neohesperidin dihydrochalcone, but due to high requirements for production management and equipment and high energy consumption, the production cost of neohesperidin dihydrochalcone was high, which greatly restricted its application. Later, some people studied temperature, pressure and catalysts, and achieved the synthesis of neohesperidin dihydrochalcone under normal temperature and pressure conditions. Recently, through the optimization of the catalyst in the process of synthesizing neohesperidin dihydrochalcone, a new breakthrough in the purity and yield of its product has been achieved.

[0003] Palladium-carbon catalyst is a catalytic material prepared by loading precious metal palladium onto carrier activated carbon. It has the characteristics of small feed amount, high activity, stable performance, green environmental protection and easy recycling. It is widely used in the pharmaceutical industry, petrochemical industry, dye and fragrance industry, electronics industry and other fine chemical reaction processes. Palladium-carbon catalyst is a supported catalyst. The more commonly used preparation methods are: impregnation method, hydrolysis impregnation method, ion exchange method and impregnation precipitation method. When there are one or more side reactions in the product of the catalytic reaction, it is often necessary to balance the relationship between selectivity, activity and catalyst stability. It is particularly important to select a suitable and efficient catalyst.

[0004] The raw materials and reaction process of organic hydrogenation are complicated, and there are many types of palladium-carbon catalysts. It is difficult to achieve the universal use of one or more catalysts, and most catalysts are specific. The reaction of synthesizing neohesperidin dihydrochalcone from neohesperidin belongs to a double bond hydrogenation reaction. Due to the extremely strong double bond conjugation effect in the reaction, the difficulty of hydrogenation increases, and conventional catalysts cannot meet the synergy of their activity, selectivity and stability. Therefore, the requirements for new catalysts are extremely high, which is manifested in that they must have strong reaction activity, extremely high selectivity of the catalyst, and stability. Therefore, it is particularly important to design and prepare a catalyst with high activity, selectivity and stability for the synthesis of neohesperidin dihydrochalcone. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a method for preparing a catalyst for synthesizing neohesperidin dihydrochalcone in view of the above-mentioned deficiencies of the prior art. The prepared catalyst has a yield of more than 97.0% in the reaction of synthesizing neohesperidin dihydrochalcone and has high reaction performance.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for preparing a catalyst for synthesizing neohesperidin dihydrochalcone, characterized in that it comprises the following steps:

[0007] Step 1, boiling the activated carbon in a nitric acid solution, filtering, and washing with water to obtain acid-treated activated carbon;

[0008] Step 2: placing the acid-treated activated carbon in step 1 in a mixed solution of sodium bicarbonate and ammonium thiosulfate at 90° C. to 110° C., stirring for 1 h to 2 h, filtering, and washing with water to obtain mixed solution-treated activated carbon;

[0009] Step 3: placing the mixed solution treated activated carbon in step 2 in an auxiliary solution and stirring for 1 h to 2 h at 35° C. to 65° C., then controlling the pH to 8.5 to 10.5 with an ammonia solution, filtering, and obtaining auxiliary modified activated carbon; the auxiliary is bismuth nitrate or manganese nitrate;

[0010] Step 4: mixing the additive-modified activated carbon with the mesoporous silica carrier to obtain a mixed carrier;

[0011] Step 5, placing the mixed carrier obtained in step 4 in an ammonium chloropalladate solution, stirring for 30 min to 60 min, controlling the pH of the slurry to be 8 to 10 during the stirring process, filtering, washing, and obtaining a catalyst precursor;

[0012] Step six: reducing the catalyst precursor described in step five to obtain a catalyst for synthesizing neohesperidin dihydrochalcone.

[0013] The above-mentioned method for preparing a catalyst for synthesizing neohesperidin dihydrochalcone is characterized in that the specific surface area of ​​the activated carbon in step 1 is 800m 2 / g~1300m 2 / g; the mass of the nitric acid solution in step one is 8 to 10 times the mass of the activated carbon, and the mass percentage concentration of the nitric acid solution is 3% to 5%; the cooking temperature in step one is 80°C to 100°C, and the cooking time is 1h to 2h; washing with water in step one to a pH of 6 to 8.

[0014] The above-mentioned method for preparing a catalyst for synthesizing neohesperidin dihydrochalcone is characterized in that the mass of the mixed solution of sodium bicarbonate and ammonium thiosulfate in step 2 is 8 to 10 times the mass of the activated carbon in step 1, the mass percentage concentration of the solute in the mixed solution of sodium bicarbonate and ammonium thiosulfate is 2% to 5%, and the mass ratio of sodium bicarbonate to ammonium thiosulfate is 1:1; in step 2, washing with water to a pH of 6.

[0015] The above-mentioned method for preparing a catalyst for synthesizing neohesperidin dihydrochalcone is characterized in that the mass of the auxiliary solution in step three is 5 to 8 times the mass of the activated carbon in step one, the mass percentage concentration of the auxiliary solution is 1% to 2%, and the mass percentage concentration of the ammonia solution is 5% to 10%; the mixing method in step four is mechanical stirring mixing, and the mass percentage of mesoporous silica in the mixed carrier is 5% to 30%.

[0016] The above-mentioned method for preparing a catalyst for synthesizing neohesperidin dihydrochalcone is characterized in that the concentration of palladium ions in the ammonium chloropalladate solution in step 5 is 0.1 g / mL to 0.5 g / mL, and an ammonia solution with a mass percentage concentration of 5% to 10% is used to control the pH of the slurry during the stirring process.

[0017] The above-mentioned method for preparing a catalyst for synthesizing neohesperidin dihydrochalcone is characterized in that a reducing agent solution is used for reduction in step six, the reducing agent solution is a formic acid solution or a sodium borohydride solution, the mass concentration of the reducing agent solution is 10% to 20%, the mass of the reducing agent solution is 10 to 20 times the mass of the catalyst precursor, the reduction time is 1h to 2h, and the reduction temperature is 90°C to 100°C.

[0018] The above-mentioned method for preparing a catalyst for synthesizing neohesperidin dihydrochalcone is characterized in that the mass content of palladium in the catalyst for synthesizing neohesperidin dihydrochalcone described in step six is ​​5%.

[0019] Furthermore, the present invention provides a catalyst for synthesizing neohesperidin dihydrochalcone prepared by the above preparation method.

[0020] Furthermore, the present invention provides a method for catalytically synthesizing neohesperidin dihydrochalcone using the above-mentioned catalyst for synthesizing neohesperidin dihydrochalcone, characterized in that it comprises: mixing neohesperidin, a solvent, potassium hydroxide and the catalyst for reaction at a temperature of 30°C±2°C to obtain neohesperidin dihydrochalcone.

[0021] The above method is characterized in that the conditions of the mixed reaction include: the reaction time is 6 hours, the hydrogenation pressure is 0.5 MPa, the mass of the catalyst is 0.2 times the mass of neohesperidin, the solvent is water, and the mass of the water is 16 times the mass of neohesperidin.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] 1. The preparation method of the catalyst of the present invention comprises pretreatment of activated carbon with a strong oxidizing acid, secondary treatment of the activated carbon with a mixed solution of sodium bicarbonate and ammonium thiosulfate, modification of the secondary treated activated carbon with bismuth nitrate or manganese nitrate, mixing the modified activated carbon with mesoporous silica to obtain a carrier required for catalyst preparation, and then obtaining the required catalyst through adsorption and reduction. The obtained catalyst is used in the reaction of synthesizing neohesperidin dihydrochalcone with a yield of more than 97.0%, and has high reaction performance.

[0024] 2. The present invention uses a strong oxidizing acid to pretreat the carrier, which can not only enrich the oxygen-containing functional groups on the surface of the activated carbon and promote the activity of the catalyst, but also the strong acid performance effectively removes ash impurities in the activated carbon, playing the role of a clean carrier. In addition, the strong oxidizing acid environment modifies the pore structure of the activated carbon, making the active component metal more evenly and firmly distributed in the activated carbon pores, thereby promoting the overall activity of the catalyst.

[0025] 3. The present invention uses sodium bicarbonate and ammonium thiosulfate to perform secondary treatment on the carrier. Under heating conditions, the oxygen-containing groups in sodium bicarbonate and the nitrogen-containing groups in ammonium thiosulfate can be implanted on the surface of the activated carbon, enriching the oxygen-containing groups and nitrogen-containing groups on the surface of the carrier again. The introduction of these groups can further promote the activity and anti-toxicity of the catalyst. At the same time, the pH value of the carrier after the strong acid pretreatment of the activated carbon can be improved to be close to the weak acid neutral environment, which is convenient for the later loading of the auxiliary agent and the precious metal component on the carrier.

[0026] 4. The present invention can fully modify the activated carbon by introducing bismuth nitrate or manganese nitrate as an auxiliary agent, which plays an important role in the anchoring of precious metals during the adsorption process. The introduction of the auxiliary agent can make the active components more evenly dispersed on the carrier, and can prevent the agglomeration of the active components during the use of the catalyst. The obtained catalyst not only has strong reaction activity, but also has improved stability, which promotes the number of times the catalyst can be used.

[0027] 5. The present invention adopts modified activated carbon mixed with mesoporous silica as a carrier, which can promote the distribution of active components in the carrier. At the same time, the carrier doped with mesoporous silica has high gas-solid-liquid mass transfer efficiency during the hydrogenation reaction, and the relative proportion of active components per unit volume increases, thereby improving its activity. In addition, the hydrogenation liquid filtration speed of the carrier catalyst doped with mesoporous silica is faster than that of the undoped carrier after the reaction.

[0028] 6. The preparation method of the present invention is relatively simple, easy to produce and operate, and has low cost.

[0029] The technical solution of the present invention is further described in detail below in conjunction with embodiments. DETAILED DESCRIPTION

[0030] The present invention is further described below in conjunction with specific embodiments, so as to more clearly explain the advantages of the present invention. The embodiments described are only exemplary and do not constitute any limitation to the scope of the present invention.

[0031] Example 1

[0032] This embodiment provides a method for preparing a catalyst for synthesizing neohesperidin dihydrochalcone, comprising:

[0033] Step 1: boil 100g of activated carbon in 800g of nitric acid solution, filter and wash with water to obtain acid-treated activated carbon; the mass percentage concentration of the nitric acid solution is 3%; the boiling temperature is 80°C and the boiling time is 1h; the washing is to wash with water until the pH is 6; the specific surface area of ​​the activated carbon is 1000m 2 / g or so;

[0034] Step 2, under the temperature condition of 90° C., stirring the acid-treated activated carbon in step 1 in 1000 g of sodium bicarbonate and ammonium thiosulfate solution for 2 h, filtering, and washing with water to obtain sodium bicarbonate and ammonium thiosulfate treated activated carbon; the mass percentage concentration of the sodium bicarbonate and ammonium thiosulfate solution is 2%, and the mass ratio of sodium bicarbonate to ammonium thiosulfate is 1:1; the washing with water is washing with water until the pH is 6;

[0035] Step 3, under the condition of 50°C, placing the activated carbon treated with sodium bicarbonate and ammonium thiosulfate in step 2 in 500g of bismuth nitrate solution and stirring for 1h, and controlling its pH to 10.0 by an ammonia solution, filtering, and obtaining bismuth nitrate modified activated carbon; the mass percentage concentration of bismuth nitrate in the bismuth nitrate solution is 1%, and the mass percentage concentration of the ammonia solution is 5%;

[0036] Step 4: mixing the bismuth nitrate modified activated carbon and the mesoporous silica carrier in a mass ratio of 0.95:0.05, wherein the mixing method is mechanical stirring;

[0037] Step 5: according to the preset palladium content in the Pd / C catalyst (the mass content of palladium in the catalyst is 5%), the mixed carrier carbon described in step 4 is placed in an ammonium chloropalladate solution, stirred for 30 minutes, the pH of the system is controlled to 8.0 during the stirring process, filtered, washed, and a catalyst precursor is obtained; the palladium ion concentration in the ammonium chloropalladate solution is 0.1 g / mL; the adsorption system slurry is controlled with a 5% ammonia solution by mass percentage;

[0038] Step six, reducing the catalyst precursor of step five to obtain a catalyst for the synthesis of neohesperidin dihydrochalcone; the reduction is carried out by a reducing agent solution, the reducing agent solution is a formic acid solution, the reduction time is 1h, and the reduction temperature is 90°C; the volume of the reducing agent solution is 20 times the mass of Pd, and the mass percentage of the reducing agent solution is 20%.

[0039] Comparative Example 1

[0040] In this comparative example, the activated carbon was not treated. The ammonium chloropalladate solution and the activated carbon were directly stirred and mixed, stabilized for 1 hour, aged for 12 hours, reduced with 20% formic acid solution for 1 hour, washed, and filtered to obtain a Pd / C catalyst.

[0041] Comparative Example 2

[0042] In this comparative example, the activated carbon was treated with 4% nitric acid by mass percentage (i.e., treated according to step 1 in the embodiment), filtered, and washed. The obtained carrier was stirred and mixed with ammonium chloropalladate solution, stabilized for 1 hour, aged for 12 hours, reduced with 20% formic acid solution for 1 hour, washed, and filtered to obtain a Pd / C catalyst.

[0043] Comparative Example 3

[0044] In this comparative example, the activated carbon was treated with 4% nitric acid by mass percentage (i.e., treated according to step 1 in the embodiment), and the obtained carrier was stirred in sodium bicarbonate and ammonium thiosulfate solution at 100°C for 1.5 hours, filtered, and washed (i.e., treated according to step 2 in the embodiment). The obtained carrier was then stirred and mixed with ammonium chloropalladate solution, stabilized for 1 hour, aged for 12 hours, reduced with 20% formic acid solution for 1 hour, washed, and filtered to obtain a Pd / C catalyst.

[0045] Comparative Example 4

[0046] In this comparative example, the activated carbon was treated with 4% nitric acid by mass percentage (i.e., treated according to step 1 in the embodiment), and the obtained carrier was stirred in sodium bicarbonate and ammonium thiosulfate solution at 100°C for 1.5h, filtered, and washed (i.e., treated according to step 2 in the embodiment). The obtained carrier was stirred with bismuth nitrate solution for 1.5h, pH was controlled at 10.0, and modified (i.e., treated according to step 3 in the embodiment). The obtained carrier was then stirred and mixed with ammonium chloropalladate solution, stabilized for 1h, aged for 12h, reduced with 20% formic acid solution for 1h, washed, filtered, and a Pd / C catalyst was obtained.

[0047] Comparative Example 5

[0048] In this comparative example, mesoporous silica is used as a carrier. The ammonium chloropalladate solution and the mesoporous silica are directly stirred and mixed, stabilized for 1 hour, aged for 12 hours, reduced with 20% formic acid solution for 1 hour, washed, and filtered to obtain a Pd / SiO2 catalyst.

[0049] Example 2

[0050] This embodiment provides a method for preparing a catalyst for synthesizing neohesperidin dihydrochalcone, comprising:

[0051] Step 1: boil 100g of activated carbon in 1000g of nitric acid solution, filter and wash with water to obtain acid-treated activated carbon; the mass percentage concentration of the nitric acid solution is 5%; the boiling temperature is 100°C and the boiling time is 1h; the washing is to wash with water until the pH is 7; the specific surface area of ​​the activated carbon is 800m 2 / g or so;

[0052] Step 2, under the temperature condition of 110° C., stirring the acid-treated activated carbon in 1000 g of sodium bicarbonate and ammonium thiosulfate solution for 2 h, filtering, and washing with water to obtain sodium bicarbonate and ammonium thiosulfate treated activated carbon; the mass percentage concentration of the sodium bicarbonate and ammonium thiosulfate solution is 5%, and the mass ratio of sodium bicarbonate to ammonium thiosulfate is 1:1; the washing with water is washing with water until the pH is 6;

[0053] Step 3, under the condition of 50° C., placing the activated carbon treated with sodium bicarbonate and ammonium thiosulfate in step 2 in 800 g of bismuth nitrate solution and stirring for 1 h, and controlling the pH value to 8.5 by an ammonia solution, filtering, and obtaining bismuth nitrate modified activated carbon; the mass percentage concentration of bismuth nitrate in the bismuth nitrate solution is 2%, and the mass percentage concentration of the ammonia solution is 10%;

[0054] Step 4: mixing the bismuth nitrate modified activated carbon and the mesoporous silica carrier in a mass ratio of 0.95:0.05, wherein the mixing method is mechanical stirring;

[0055] Step 5: according to the preset palladium content in the Pd / C catalyst (the mass content of palladium in the catalyst is 5%), the mixed carrier carbon described in step 4 is placed in an ammonium chloropalladate solution, stirred for 40 minutes, the pH of the system is controlled to 9.0 during the stirring process, filtered, washed, and a catalyst precursor is obtained; the palladium ion concentration in the ammonium chloropalladate solution is 0.5 g / mL; the adsorption system slurry is controlled with a 10% ammonia solution by mass percentage concentration;

[0056] Step six, reducing the catalyst precursor described in step five to obtain a catalyst for the synthesis of neohesperidin dihydrochalcone; the reduction is carried out by a reducing agent solution, the reducing agent solution is a sodium borohydride solution, the reduction time is 2h, and the reduction temperature is 90°C; the volume of the reducing agent solution is 10 times the mass of Pd, and the mass percentage of the reducing agent solution is 20%.

[0057] Example 3

[0058] This embodiment provides a method for preparing a catalyst for synthesizing neohesperidin dihydrochalcone, comprising:

[0059] Step 1: boil 100g of activated carbon in 900g of nitric acid solution, filter and wash with water to obtain acid-treated activated carbon; the mass percentage concentration of the nitric acid solution is 4%; the boiling temperature is 90°C and the boiling time is 1.5h; the washing is to wash with water until the pH is 6; the specific surface area of ​​the activated carbon is 1300m 2 / g or so;

[0060] Step 2, under the temperature condition of 100° C., stirring the acid-treated activated carbon in step 1 in 900 g of sodium bicarbonate and ammonium thiosulfate solution for 1.5 h, filtering, and washing with water to obtain sodium bicarbonate and ammonium thiosulfate treated activated carbon; the mass percentage concentration of the sodium bicarbonate and ammonium thiosulfate solution is 4%, and the mass ratio of sodium bicarbonate to ammonium thiosulfate is 1:1; the washing with water is washing with water until the pH is 6;

[0061] Step 3, under the condition of 35°C, placing the activated carbon treated with sodium bicarbonate and ammonium thiosulfate in step 2 in 600g manganese nitrate solution and stirring for 2h, and controlling the pH value to 10.0 by ammonia solution, filtering, and obtaining manganese nitrate modified activated carbon; the mass percentage concentration of manganese nitrate in the manganese nitrate solution is 1.5%, and the mass percentage concentration of the ammonia solution is 8%;

[0062] Step 4: Mixing the manganese nitrate modified activated carbon and the mesoporous silica carrier in a mass ratio of 0.85:0.15, wherein the mixing method is mechanical stirring;

[0063] Step 5: according to the preset palladium content in the Pd / C catalyst (the mass content of palladium in the catalyst is 5%), the mixed carrier carbon described in step 4 is placed in an ammonium chloropalladate solution, stirred for 60 minutes, the pH of the stirring process is controlled to 10.0, filtered, washed, and a catalyst precursor is obtained; the palladium ion concentration in the ammonium chloropalladate solution is 0.2 g / mL; the adsorption system slurry is controlled with a 7% ammonia solution by mass percentage;

[0064] Step six, reducing the catalyst precursor of step five to obtain a catalyst for the synthesis of neohesperidin dihydrochalcone; the reduction is carried out by a reducing agent solution, the reducing agent solution is a sodium borohydride solution, the reduction time is 1.5h, and the reduction temperature is 100°C; the volume of the reducing agent solution is 15 times the mass of Pd, and the mass percentage of the reducing agent solution is 10%.

[0065] Example 4

[0066] This embodiment provides a method for preparing a catalyst for synthesizing neohesperidin dihydrochalcone, comprising:

[0067] Step 1: boil 100g of activated carbon in 1000g of nitric acid solution, filter and wash with water to obtain acid-treated activated carbon; the mass percentage concentration of the nitric acid solution is 5%; the boiling temperature is 100°C and the boiling time is 2h; the washing is to wash with water until the pH is 8; the specific surface area of ​​the activated carbon is 1000m 2 / g or so;

[0068] Step 2, under the condition of 90°C, stirring the acid-treated activated carbon in 800g sodium bicarbonate and ammonium thiosulfate solution for 1h, filtering, and washing with water to obtain sodium bicarbonate and ammonium thiosulfate treated activated carbon; the mass percentage concentration of the sodium bicarbonate and ammonium thiosulfate solution is 5%, and the mass ratio of sodium bicarbonate to ammonium thiosulfate is 1:1; the washing with water is washing with water until the pH is 6;

[0069] Step 3, under the condition of 65°C, placing the activated carbon treated with sodium bicarbonate and ammonium thiosulfate in step 2 in 700g bismuth nitrate solution and stirring for 1.5h, and controlling the pH value to 10.5 by an ammonia solution, filtering, and obtaining bismuth nitrate modified activated carbon; the mass percentage concentration of bismuth nitrate in the bismuth nitrate solution is 2%, and the mass percentage concentration of the ammonia solution is 10%;

[0070] Step 4: Mixing the bismuth nitrate modified activated carbon and the mesoporous silica carrier in a mass ratio of 0.70:0.30, wherein the mixing method is mechanical stirring;

[0071] Step 5: according to the preset palladium content in the Pd / C catalyst (the mass content of palladium in the catalyst is 5%), the mixed carrier carbon described in step 4 is placed in an ammonium chloropalladate solution, stirred for 45 minutes, the pH of the system is controlled to 9.0 during the stirring process, filtered, washed, and a catalyst precursor is obtained; the palladium ion concentration in the ammonium chloropalladate solution is 0.4 g / mL; the adsorption system slurry is controlled with a 10% ammonia solution by mass percentage concentration;

[0072] Step six, reducing the catalyst precursor of step five to obtain a catalyst for the synthesis of neohesperidin dihydrochalcone; the reduction is carried out by a reducing agent solution, the reducing agent solution is a sodium borohydride solution, the reduction time is 2h, and the reduction temperature is 95°C; the volume of the reducing agent solution is 20 times the mass of Pd, and the mass percentage of the reducing agent solution is 15%.

[0073] Application Example 1

[0074] This application example provides a method for synthesizing neohesperidin dihydrochalcone using the catalysts of Examples 1 to 4 and Comparative Example 1, comprising:

[0075] Under the temperature condition of 30℃±2℃, 10g of neohesperidin, 160g of water and the catalyst were mixed and reacted for 6h, and the reaction hydrogen pressure was 0.5MPa to obtain neohesperidin dihydrochalcone; the mass percentage content of Pd in ​​the catalyst was 5%. The purity of the product in the system after the reaction was analyzed by liquid chromatography, the materials in the reactor were separated, and the crude product yield was calculated. The results are shown in Table 1.

[0076] Table 1 Neohesperidin dihydrochalcone catalyst reaction results

[0077]

[0078]

[0079] As can be seen from Table 1, the product purity of the reaction of the dihydrochalcone catalyst for synthesizing neohesperidin prepared by the method of the present invention is significantly higher than that of the traditional catalyst (Comparative Example 1), and the product purity can reach up to 99.4%.

[0080] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural change made to the above embodiment according to the technical essence of the invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A method for preparing a catalyst for synthesizing neohesperidin dihydrochalcone, characterized in that: The following steps are involved: Step 1, boiling the activated carbon in a nitric acid solution, filtering, and washing with water to obtain acid-treated activated carbon; Step 2: placing the acid-treated activated carbon in step 1 in a mixed solution of sodium bicarbonate and ammonium thiosulfate at 90° C. to 110° C., stirring for 1 h to 2 h, filtering, and washing with water to obtain mixed solution-treated activated carbon; Step 3: placing the mixed solution treated activated carbon in step 2 in an auxiliary solution and stirring for 1 h to 2 h at 35° C. to 65° C., then controlling the pH to 8.5 to 10.5 with an ammonia solution, filtering, and obtaining auxiliary modified activated carbon; the auxiliary is bismuth nitrate or manganese nitrate; Step 4: mixing the additive-modified activated carbon with the mesoporous silica carrier to obtain a mixed carrier; Step 5, placing the mixed carrier obtained in step 4 in an ammonium chloropalladate solution, stirring for 30 min to 60 min, controlling the pH of the slurry to be 8 to 10 during the stirring process, filtering, washing, and obtaining a catalyst precursor; Step six: reducing the catalyst precursor described in step five to obtain a catalyst for synthesizing neohesperidin dihydrochalcone.

2. The method for preparing a catalyst for synthesizing neohesperidin dihydrochalcone according to claim 1, characterized in that: The specific surface area of ​​the activated carbon in step 1 is 800m 2 / g~1300m 2 / g; the mass of the nitric acid solution in step one is 8 to 10 times the mass of the activated carbon, and the mass percentage concentration of the nitric acid solution is 3% to 5%; the cooking temperature in step one is 80°C to 100°C, and the cooking time is 1h to 2h; washing with water in step one to a pH of 6 to 8.

3. The method for preparing a catalyst for synthesizing neohesperidin dihydrochalcone according to claim 1, characterized in that: The mass of the mixed solution of sodium bicarbonate and ammonium thiosulfate in step 2 is 8 to 10 times the mass of the activated carbon in step 1, the mass percentage concentration of the solute in the mixed solution of sodium bicarbonate and ammonium thiosulfate is 2% to 5%, and the mass ratio of sodium bicarbonate to ammonium thiosulfate is 1:1; in step 2, washing with water until the pH is 6.

4. The method for preparing a catalyst for synthesizing neohesperidin dihydrochalcone according to claim 1, characterized in that: The mass of the auxiliary solution in step 3 is 5 to 8 times the mass of the activated carbon in step 1, the mass percentage concentration of the auxiliary solution is 1% to 2%, and the mass percentage concentration of the ammonia solution is 5% to 10%; the mixing method in step 4 is mechanical stirring mixing, and the mass percentage of mesoporous silica in the mixed carrier is 5% to 30%.

5. The method for preparing a catalyst for synthesizing neohesperidin dihydrochalcone according to claim 1, characterized in that: The concentration of palladium ions in the ammonium chloropalladate solution in step 5 is 0.1 g / mL to 0.5 g / mL, and an ammonia solution with a mass percentage concentration of 5% to 10% is used to control the pH of the slurry during the stirring process.

6. The method for preparing a catalyst for synthesizing neohesperidin dihydrochalcone according to claim 1, characterized in that: In step six, a reducing agent solution is used for reduction. The reducing agent solution is formic acid solution or sodium borohydride solution. The mass concentration of the reducing agent solution is 10% to 20%. The mass of the reducing agent solution is 10 to 20 times the mass of the catalyst precursor. The reduction time is 1h to 2h and the reduction temperature is 90°C to 100°C.

7. The method for preparing a catalyst for synthesizing neohesperidin dihydrochalcone according to claim 1, characterized in that: The mass content of palladium in the catalyst used for synthesizing neohesperidin dihydrochalcone in step six is ​​5%.

8. A catalyst for synthesizing neohesperidin dihydrochalcone prepared by the preparation method according to any one of claims 1 to 7.

9. A method for catalytically synthesizing neohesperidin dihydrochalcone using the catalyst for synthesizing neohesperidin dihydrochalcone as claimed in claim 8, characterized in that: include: Under the temperature condition of 30°C±2°C, neohesperidin, solvent, potassium hydroxide and the catalyst are mixed for reaction to obtain neohesperidin dihydrochalcone.

10. The method according to claim 9, characterized in that The conditions of the mixed reaction include: reaction time of 6 hours, hydrogenation pressure of 0.5 MPa, the mass of the catalyst is 0.2 times the mass of neohesperidin, the solvent is water, and the mass of the water is 16 times the mass of neohesperidin.

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