A method for preparing vanillin from ferulic acid

Abstract

The application discloses a method for preparing vanillin by using ferulic acid as raw material, and belongs to the technical field of organic chemical synthesis, which uses ferulic acid as raw material, reduces the reaction of isomerization of eugenol into isoeugenol, avoids using a large amount of alkali solution, and has the characteristics of clean and environmental protection, simple process, less side reaction, high product yield, etc.; the method comprises the following steps: (1) taking ferulic acid, adding an alcohol solvent, ferric chloride and hydrogen peroxide, and reacting after heating; (2) concentrating and recovering the alcohol solvent from the reaction liquid obtained in the step (1); (3) adding an ester solvent and an alkali aqueous solution to the alcohol solvent obtained in the step (2) for washing, layering after standing, and collecting the ester solvent layer solution; (4) concentrating and recovering the ester solvent from the ester solvent layer solution obtained in the step (3), recrystallizing the obtained solid with an ethanol aqueous solution, performing suction filtration, washing with water, and drying to obtain a finished product.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of organic chemical synthesis, and more particularly to a method for preparing vanillin from ferulic acid. BACKGROUND

[0002] Vanillin is a commonly used spice, and its production methods mainly include plant extraction method, biological conversion method, chemical synthesis method and natural product semi-synthesis method. The plant extraction method is limited by the raw material plant and has limited yield. The biological conversion method is clean, less polluting and safe to produce, but the reaction system is complex, the yield is low, and the separation and purification are difficult. The chemical synthesis method has a long process route, high equipment requirements, serious environmental pollution and poor product aroma quality. The vanillin prepared by the natural product semi-synthesis method has good aroma quality and sufficient raw material source, and thus is widely studied.

[0003] At present, the research mainly takes eugenol as the raw material. CN104119213B discloses a preparation method of vanillin, which is characterized by: including a step of respectively taking eugenol, strong base, catalyst and first organic solvent, adding the above-mentioned substances into a reaction container respectively, heating to 60-120℃ under stirring condition, then starting to pass in oxygen, controlling the oxygen partial pressure to be 0.01-1MPa, performing oxidation reaction, ending the reaction after 4-30 hours, cooling to room temperature, adding water, the volume ratio of the water and the first organic solvent is 0.5-2, and adjusting to neutral with acid solution, recovering the first organic solvent, then extracting the water phase with second organic solvent, and performing vacuum distillation, adopting ethanol water mixed solvent crystallization, and drying to obtain vanillin. The catalyst is cobalt salt, or mixed salt of cobalt salt and copper salt, or mixed salt of cobalt salt and nickel salt. CN103626643B discloses a preparation method for synthesizing vanillin from natural eugenol, and the process method steps are as follows: 1. preparation of isoeugenol; 2. oxidation of isoeugenol; and 3. purification of vanillin crude product. The above-mentioned reaction liquid is extracted with 120ml, 100ml and 80ml of benzene for three times, the extraction liquid is combined and washed for three times, the extraction liquid is recovered by vacuum distillation, then crystallized with toluene, centrifuged and dried to obtain vanillin crude product, and the crude product is recrystallized with edible alcohol, vacuum centrifuged and dried to obtain vanillin finished product.

[0004] Current methods for preparing vanillin from eugenol all involve isomerization under alkaline conditions to isoeugenol, followed by oxidation to vanillin. These processes use large amounts of alkali for the isomerization reaction and large amounts of oxidants, generating significant amounts of waste residue and wastewater, causing severe pollution. Alternatively, the processes may require toxic catalysts such as cobalt or nickel. The reaction selectivity is also poor, producing numerous byproducts that result in low product yields and difficulties in separation and purification. Furthermore, vanillin prepared from eugenol often retains trace amounts of eugenol, affecting its aroma quality. Therefore, improving the vanillin preparation method to make the process simpler and more environmentally friendly is a new direction for future research. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing vanillin using ferulic acid as a raw material. This method uses ferulic acid as a raw material, reduces the isomerization reaction of eugenol to isoeugenol in the preparation process, and avoids the use of a large amount of alkaline solution. It has the characteristics of being clean and environmentally friendly, simple in process, with few side reactions and high product yield.

[0006] The technical solution of this invention is as follows:

[0007] A method for preparing vanillin from ferulic acid includes the following steps:

[0008] (1) Take ferulic acid, add alcohol solvent, ferric chloride and hydrogen peroxide, and heat to react;

[0009] (2) Take the reaction solution from step (1) and concentrate it to recover the alcohol solvent;

[0010] (3) Add ester solvent and alkaline aqueous solution to the alcohol solvent obtained in step (2) and wash, let stand to separate the layers, and collect the ester solvent layer solution;

[0011] (4) The ester solvent layer solution obtained in step (3) is concentrated to recover the ester solvent. The resulting solid is recrystallized with ethanol aqueous solution, filtered, washed with water, and dried to obtain the finished product.

[0012] Furthermore, in step (1), the concentration of the added hydrogen peroxide is 30%, and the ratio of the volume of the added alcohol solvent, the mass of ferric chloride, the mass of hydrogen peroxide, and the mass of ferulic acid is 2-10:0.01-0.05:1-3:1.

[0013] Furthermore, in step (1), the temperature is raised to 20–40°C and the reaction time is 4–12 hours.

[0014] Furthermore, in step (1), the alcohol solvent is one or a combination of methanol, ethanol, propanol and n-butanol.

[0015] Further, in the step (3), the volume of the ester solvent added is 3-8 times the mass of the ferulic acid, and the pH of the aqueous base solution added is 8-10, and the ester solvent is a combination of one or more of ethyl acetate, butyl acetate and ethyl formate.

[0016] Further, in the step (4), the concentration of the aqueous ethanol solution used is 20-50%, and the volume of the aqueous ethanol solution added is 4-8 times the mass of the ferulic acid.

[0017] Compared with the prior art, the method has the beneficial effects that:

[0018] In the method for preparing vanillin from ferulic acid, ferulic acid is taken, alcohol solvent, ferric chloride and hydrogen peroxide are added, and then heated for reaction; the alcohol solvent is recovered by concentration; ester solvent and aqueous base solution are added for washing, and then the solution in the ester solvent layer is collected after static separation; the ester solvent is recovered by concentration, and the obtained solid is recrystallized with aqueous ethanol, filtered, washed with water and dried to obtain the finished product. By using ferulic acid as the raw material for preparing vanillin, the reaction of isomerization of eugenol into isoeugenol is reduced, and a large amount of base solution is avoided. Hydrogen peroxide is used as the oxidizing agent, and the process does not produce waste residue and waste water, which is clean and environmentally friendly. The process is simple, the reaction temperature is 20-40℃, although the reaction time is prolonged, the reaction is carried out in more controllable conditions, which makes it more stable and safe, and the yield of the product is improved. DETAILED DESCRIPTION

[0019] The technical solutions of the present application will be further described in detail below in combination with specific embodiments, but do not constitute any limitation on the present application.

[0020] A method for preparing vanillin from ferulic acid, comprising the following steps:

[0021] (1) Ferulic acid is taken, alcohol solvent, ferric chloride and hydrogen peroxide are added, and then heated for reaction. The concentration of the hydrogen peroxide added is 30%, and the volume of the alcohol solvent added, the mass of the ferric chloride and the mass of the hydrogen peroxide are 2-10 times, 0.01-0.05 times and 1-3 times the mass of the ferulic acid, respectively. The temperature is heated to 20-40℃, and the reaction time is 4-12 hours. The alcohol solvent is a combination of one or more of methanol, ethanol, propanol and n-butanol.

[0022] (2) The reaction solution obtained in step (1) is concentrated to recover the alcohol solvent.

[0023] (3) adding ester solvent and alkaline aqueous solution into the alcohol solvent obtained in step (2) to wash, standing to separate layers, and collecting the ester solvent layer solution. The volume ratio of the ester solvent to the mass of ferulic acid is 3-8:1, the pH value of the added alkaline aqueous solution is 8-10, and the ester solvent is a combination of one or more of ethyl acetate, butyl acetate and ethyl formate.

[0024] (4) concentrating the ester solvent layer solution obtained in step (3) to recover the ester solvent, recrystallizing the obtained solid with an ethanol aqueous solution, suction filtering, washing with water, and drying to obtain the finished product. The concentration of the ethanol aqueous solution used is 20-50%, and the volume ratio of the added ethanol aqueous solution to the mass of ferulic acid is 4-8:1.

[0025] In the preparation method, the vanillin is prepared by using ferulic acid as a raw material, the preparation process reduces the reaction of isomerization of eugenol into isoeugenol, and a large amount of alkaline solution is avoided. Hydrogen peroxide is used as an oxidizing agent, the process does not produce waste residue and waste water, and is clean and environmentally friendly. The process is simple, the reaction temperature is 20-40℃, although the reaction time is prolonged, the reaction is carried out in more controllable conditions, which makes it more stable and safe, and the yield of the product is improved.

[0026] Example 1

[0027] A vanillin, the preparation process of which comprises the following steps:

[0028] (1) taking 100g of ferulic acid, adding 200mL of methanol solvent, 2g of ferric chloride and 100mL of hydrogen peroxide with a concentration of 30%, heating to 40℃ and reacting for 4 hours.

[0029] (2) concentrating the reaction solution obtained in step (1) to recover the methanol solvent.

[0030] (3) adding 300mL of butyl acetate solvent and a sodium hydroxide solution with a pH value of 8 into the methanol solvent obtained in step (2) to wash, standing to separate layers, and collecting the ester solvent layer solution.

[0031] (4) concentrating the ester solvent layer solution obtained in step (3) to recover the ester solvent, recrystallizing the obtained solid with 400mL of an ethanol aqueous solution with a concentration of 30%, suction filtering, washing with water, and drying to obtain 76.5g of vanillin, which is determined to have a liquid phase purity of 99.7% and a yield of 97.34%.

[0032] Example 2

[0033] A vanillin, the preparation process of which comprises the following steps:

[0034] (1) Take 100 g of ferulic acid, add 500 mL of ethanol solvent, 2 g of ferric chloride and 200 mL of 30% concentration hydrogen peroxide, heat to 30°C and react for 8 hours.

[0035] (2) Concentrate the reaction solution obtained in step (1) to recover the ethanol solvent.

[0036] (3) Add 400 mL of ethyl acetate solvent and a pH 9 sodium hydroxide solution to the ethanol solvent obtained in step (2) and wash, stand to separate layers, and collect the ester solvent layer solution.

[0037] (4) Concentrate the ester solvent layer solution obtained in step (3) to recover the ester solvent, and recrystallize the obtained solid with 500 mL of 30% concentration ethanol aqueous solution, filter, wash with water, and dry to obtain 77 g of vanillin, which has a liquid phase purity of 99.6% and a yield of 97.88% as determined.

[0038] Example 3

[0039] A vanillin, the preparation process of which comprises the following steps:

[0040] (1) Take 100 g of ferulic acid, add 1000 mL of ethanol solvent, 5 g of ferric chloride and 300 mL of 30% concentration hydrogen peroxide, heat to 20°C and react for 12 hours.

[0041] (2) Concentrate the reaction solution obtained in step (1) to recover the ethanol solvent.

[0042] (3) Add 800 mL of butyl acetate solvent and a pH 10 sodium hydroxide solution to the ethanol solvent obtained in step (2) and wash, stand to separate layers, and collect the ester solvent layer solution.

[0043] (4) Concentrate the ester solvent layer solution obtained in step (3) to recover the ester solvent, and recrystallize the obtained solid with 800 mL of 20% concentration ethanol aqueous solution, filter, wash with water, and dry to obtain 76.7 g of vanillin, which has a liquid phase purity of 99.5% and a yield of 97.4% as determined.

[0044] Example 4

[0045] A vanillin, the preparation process of which comprises the following steps:

[0046] (1) Take 100 g of ferulic acid, add 300 mL of propyl alcohol solvent, 1 g of ferric chloride and 100 mL of 30% concentration hydrogen peroxide, heat to 40°C and react for 4 hours.

[0047] (2) Concentrate the reaction solution obtained in step (1) to recover the propyl alcohol solvent.

[0048] (3) The n-butanol solvent obtained in step (2) is added with 700 mL of ethyl formate solvent and a sodium hydroxide solution with pH value of 10 for washing, and then left to separate into layers, and the ester solvent layer solution is collected.

[0049] (4) The ester solvent layer solution obtained in step (3) is concentrated to recover the ester solvent, and the obtained solid is recrystallized with 700 mL of 20% ethanol aqueous solution, and then filtered, washed with water and dried to obtain 76.9 g of vanillin, which is determined to have a liquid phase purity of 99.6% and a yield of 97.75%.

[0050] Example 5

[0051] A vanillin is prepared by the following steps:

[0052] (1) 100 g of ferulic acid is added with 900 mL of n-butanol solvent, 4 g of ferric chloride and 300 mL of 30% hydrogen peroxide solution, and then heated to 20°C for reaction for 12 hours.

[0053] (2) The reaction solution obtained in step (1) is concentrated to recover the n-butanol solvent.

[0054] (3) The n-butanol solvent obtained in step (2) is added with 700 mL of ethyl formate solvent and a sodium hydroxide solution with pH value of 10 for washing, and then left to separate into layers, and the ester solvent layer solution is collected.

[0055] (4) The ester solvent layer solution obtained in step (3) is concentrated to recover the ester solvent, and the obtained solid is recrystallized with 700 mL of 20% ethanol aqueous solution, and then filtered, washed with water and dried to obtain 76.9 g of vanillin, which is determined to have a liquid phase purity of 99.6% and a yield of 97.75%.

[0056] Example 6

[0057] A vanillin is prepared by the following steps:

[0058] (1) 100 g of ferulic acid is added with 800 mL of methanol solvent, 4 g of ferric chloride and 250 mL of 30% hydrogen peroxide solution, and then heated to 30°C for reaction for 10 hours.

[0059] (2) The reaction solution obtained in step (1) is concentrated to recover the methanol solvent.

[0060] (3) The methanol solvent obtained in step (2) is added with 600 mL of ethyl acetate solvent and a sodium hydroxide solution with pH value of 8 for washing, and then left to separate into layers, and the ester solvent layer solution is collected.

[0061] (4) The ester solvent layer solution obtained in step (3) is concentrated to recover the ester solvent, and the obtained solid is recrystallized with 500 mL of 40% ethanol aqueous solution, filtered, washed with water, and dried to obtain 77.1 g of vanillin, which has a liquid phase purity of 99.3% and a yield of 97.71% as determined.

[0062] Example 7

[0063] A vanillin, the preparation process of which comprises the following steps:

[0064] (1) 100 g of ferulic acid is added into 400 mL of propyl alcohol solvent, 2 g of ferric chloride, and 100 mL of 30% hydrogen peroxide, and the mixture is heated to 40°C and reacted for 6 hours.

[0065] (2) The reaction solution obtained in step (1) is concentrated to recover the propyl alcohol solvent.

[0066] (3) The propyl alcohol solvent obtained in step (2) is added with 400 mL of butyl acetate solvent and a sodium hydroxide solution with a pH value of 9, and the mixture is allowed to stand to separate into layers, and the ester solvent layer solution is collected.

[0067] (4) The ester solvent layer solution obtained in step (3) is concentrated to recover the ester solvent, and the obtained solid is recrystallized with 400 mL of 50% ethanol aqueous solution, filtered, washed with water, and dried to obtain 76.2 g of vanillin, which has a liquid phase purity of 99.4% and a yield of 96.67% as determined.

[0068] Example 8

[0069] A vanillin, the preparation process of which comprises the following steps:

[0070] (1) 100 g of ferulic acid is added into 700 mL of ethanol solvent, 4 g of ferric chloride, and 250 mL of 30% hydrogen peroxide, and the mixture is heated to 30°C and reacted for 10 hours.

[0071] (2) The reaction solution obtained in step (1) is concentrated to recover the ethanol solvent.

[0072] (3) The ethanol solvent obtained in step (2) is added with 600 mL of butyl acetate solvent and a sodium hydroxide solution with a pH value of 9, and the mixture is allowed to stand to separate into layers, and the ester solvent layer solution is collected.

[0073] (4) The ester solvent layer solution obtained in step (3) is concentrated to recover the ester solvent, and the obtained solid is recrystallized with 600 mL of 40% ethanol aqueous solution, filtered, washed with water, and dried to obtain 76.6 g of vanillin, which has a liquid phase purity of 99.8% and a yield of 97.56% as determined.

[0074] Example 9

[0075] A vanillin, the preparation process of which comprises the following steps:

[0076] (1) Take 100 g of ferulic acid, add 1000 mL of n-butanol solvent, 5 g of ferric chloride and 300 mL of 30% concentration hydrogen peroxide, heat to 40°C and react for 11 hours.

[0077] (2) Concentrate the reaction solution obtained in step (1) to recover the n-butanol solvent.

[0078] (3) Add 800 mL of ethyl formate solvent and a sodium hydroxide solution with a pH value of 9 to the n-butanol solvent obtained in step (2) and wash, stand to separate layers, and collect the ester solvent layer solution.

[0079] (4) Concentrate the ester solvent layer solution obtained in step (3) to recover the ester solvent, recrystallize the obtained solid with 700 mL of 50% concentration ethanol aqueous solution, perform suction filtration, wash with water, and dry to obtain 76.9 g of vanillin, which is determined to have a liquid phase purity of 99.6% and a yield of 97.75%.

[0080] Example 10

[0081] A vanillin, the preparation process of which comprises the following steps:

[0082] (1) Take 100 g of ferulic acid, add 200 mL of propyl alcohol solvent, 1 g of ferric chloride and 100 mL of 30% concentration hydrogen peroxide, heat to 20°C and react for 9 hours.

[0083] (2) Concentrate the reaction solution obtained in step (1) to recover the propyl alcohol solvent.

[0084] (3) Add 300 mL of ethyl acetate solvent and a sodium hydroxide solution with a pH value of 8 to the propyl alcohol solvent obtained in step (2) and wash, stand to separate layers, and collect the ester solvent layer solution.

[0085] (4) Concentrate the ester solvent layer solution obtained in step (3) to recover the ester solvent, recrystallize the obtained solid with 400 mL of 20% concentration ethanol aqueous solution, perform suction filtration, wash with water, and dry to obtain 76.8 g of vanillin, which is determined to have a liquid phase purity of 99.6% and a yield of 97.62%.

[0086] According to the preparation processes of examples 1-10 and the obtained vanillin, the vanillin prepared by the preparation method of the present application has the following advantages compared with the vanillin prepared by the existing preparation method: the preparation process does not use a large amount of alkali solution, hydrogen peroxide is used as the oxidizing agent, the process does not produce waste residue and waste water, and is clean and environmentally friendly. The whole preparation process has few side reactions, and the product yield is high.

[0087] The above merely describes preferred embodiments of the present application, and any modification, equivalent replacement, and improvement within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing vanillin from ferulic acid, characterized by, The method comprises the following steps: (1) taking ferulic acid, adding alcohol solvent, ferric chloride and hydrogen peroxide, and heating to react; (2) concentrating and recovering the alcohol solvent from the reaction solution obtained in step (1); (3) adding ester solvent and alkaline aqueous solution to the alcohol solvent obtained in step (2), and standing to separate into layers, and collecting the ester solvent layer solution; (4) concentrating and recovering the ester solvent from the ester solvent layer solution obtained in step (3), recrystallizing the obtained solid with ethanol aqueous solution, and drying to obtain the product.

2. The method of preparing vanillin from ferulic acid according to claim 1, characterized in that, In step (1), the concentration of the hydrogen peroxide added is 30%, the volume of the alcohol solvent added, the mass of the ferric chloride added, the mass of the hydrogen peroxide added, and the mass of the ferulic acid are in the ratio of 2-10:0.01-0.05:1-3:

1.

3. The method of preparing vanillin from ferulic acid according to claim 1 or 2, characterized in that, In step (1), the heating temperature is 20-40℃, and the reaction time is 4-12 hours.

4. The method of preparing vanillin from ferulic acid according to claim 1 or 2, characterized in that, In step (1), the alcohol solvent is one or a combination of methanol, ethanol, propanol and n-butanol.

5. The method of preparing vanillin from ferulic acid according to claim 4, characterized in that, In step (3), the volume of the ester solvent added and the mass of the ferulic acid are in the ratio of 3-8:1, the pH value of the alkaline aqueous solution added is 8-10, and the ester solvent is one or a combination of ethyl acetate, butyl acetate and ethyl formate.

6. The method of preparing vanillin from ferulic acid according to claim 5, characterized in that, In step (4), the concentration of the ethanol aqueous solution used is 20-50%, and the volume of the ethanol aqueous solution added and the mass of the ferulic acid are in the ratio of 4-8:1.