Stable production method of antioxidant butylated hydroxyanisole
By separating and adjusting the concentration of the acid catalyst, the problems of reaction speed and selective fluctuations in the production of antioxidant BHA are solved, and the stability and cost of BHA yield are reduced, and solid waste emissions are reduced.
Patent Information
- Application Number
- CN202411152293.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-21
- Publication Date
- 2025-01-03
AI Technical Summary
In the existing antioxidant BHA production methods, direct application of the catalyst without treatment leads to fluctuations in reaction speed and selective fluctuations, resulting in a decrease in the yield of BHA of the main product and the production process cannot be controlled smoothly.
The acidic catalyst is recovered by separation, adjustment of its concentration and supplementing to initial levels for the next batch production, combining the steps of the alkylation reaction and the distillation process to ensure the stability of reaction speed and selectivity.
The stable control of reaction speed and selectivity in the production process of antioxidant BHA is achieved, which reduces side reactions, increases the total product yield, reduces costs and reduces solid waste emissions.
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Figure CN119241340A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of production of antioxidant BHA, and in particular to a stable production method of antioxidant butylated hydroxyanisole. Background Art
[0002] Antioxidant butyl hydroxyanisole, referred to as antioxidant BHA, is a mixture of 2-butyl hydroxyanisole (2-BHA) and 3-butyl hydroxyanisole (3-BHA), CAS number: 25013-16-5, molecular formula: C11H16O2, molecular weight: 180.25. BHA is a white to slightly yellow crystal or waxy solid, with a melting point of 48-63°C and a boiling point of 264-270°C (98kPa). It has a slight phenolic taste at high concentrations and is easily soluble in ethanol (25g / 100mL, 25°C), glycerol (1g / 100mL, 25°C), lard (50g / 100mL, 50°C), corn oil (30g / 100mL, 25°C), peanut oil (40g / 100mL, 25°C) and propylene glycol (50g / 100mL, 25°C), but insoluble in water. BHA is heat stable, has good durability, is not easily destroyed under weak alkaline conditions, and does not color when reacting with metal ions. The antioxidant effect of 3-BHA is 1.5 to 2 times stronger than that of 2-BHA, and the combination of the two has a synergistic effect. BHA has a wide range of applications, mainly in animal fat, cheese, biscuits, meat, etc. The antioxidant effect of 0.02% is 10% higher than that of 0.01%, but the effect decreases when the dosage exceeds 0.02%.
[0003] In the prior art, the production method of antioxidant BHA is as follows: p-hydroxyanisole (MEHQ) is added with a certain amount of solvent, and in the presence of a certain concentration of acid solution catalyst, alkylation reaction is carried out with isobutylene to generate main products 3-BHA and 2-BHA, and a certain amount of by-product impurity di-tert-butyl hydroxyanisole. After the reaction is completed, the lower layer of acid solution is recovered by liquid-liquid stratification and can be used as a catalyst for the next batch of reactions.
[0004] The main problem with this method is that the catalyst has poor stability when directly applied without any treatment. Although there is a loss of about 5-6% in each layered recovery of the acid solution, with the continuous application of the recovered acid solution, under the same reaction conditions, the reaction rate (measured in terms of the residual amount of raw material MEHQ in the reaction mixture) gradually increases, while the reaction selectivity gradually decreases (the content of the by-product impurity di-tert-butyl hydroxyanisole in the reaction mixture gradually increases), ultimately resulting in a decrease in the yield of the main product BHA and the inability to smoothly control the production process. Summary of the invention
[0005] The present invention aims to provide a stable production method of butylated hydroxyanisole, an antioxidant, in view of the deficiencies in the prior art, which can better suppress the fluctuation of reaction rate and reaction selectivity in the production process of the antioxidant BHA and stably control the reaction rate and selectivity in the production process.
[0006] According to the purpose of the present invention, a stable production method of antioxidant butylated hydroxyanisole is provided, comprising the following steps:
[0007] S1, p-hydroxyanisole, an acidic catalyst and a solvent are mixed, heated to a reaction temperature, and then isobutylene is introduced to carry out an alkylation reaction to a reaction end point;
[0008] S2. After the reaction is completed, the acid catalyst is separated and recovered, and the oil phase is distilled to recover the unreacted raw materials, the finished product butyl hydroxyanisole and the by-product impurities;
[0009] S3, repeating steps S1 and S2 to produce the next batch of butylated hydroxyanisole until the required amount of butylated hydroxyanisole is obtained;
[0010] Among them, starting from the second batch, the current batch of acidic catalysts all use the acidic catalysts recovered from the previous batch and adjusted to the initial concentration. Moreover, after each use of the recovered acidic catalyst for 5 to 6 times, the mass of the recovered acidic catalyst is supplemented to be equal to the initial mass, and the concentration is adjusted to the same as the initial concentration, and then used for the production of the next batch, thereby smoothly controlling the reaction rate and selectivity in the production process.
[0011] As an optional embodiment, the acidic catalyst includes an aqueous solution of sulfuric acid, hydrochloric acid, p-toluenesulfonic acid or phosphoric acid.
[0012] As an optional embodiment, the concentration of the acidic catalyst is 60 to 85 wt.%.
[0013] As an optional embodiment, the solvent includes toluene, xylene, MIBK or cyclohexanone.
[0014] As an optional embodiment, in step S1, the ratio of p-hydroxyanisole, acidic catalyst and solvent is 0.25 mol: (30-50) g: (60-120) mL.
[0015] As an optional embodiment, in step S1, the reaction temperature is 60-100°C.
[0016] As an optional embodiment, in step S1, the reaction time of the alkylation reaction is 4 to 7 hours.
[0017] As an optional implementation, in step S2, the lower layer of acidic catalyst is recovered by liquid-liquid stratification, and the recovered acidic catalyst is analyzed for concentration by acid-base titration and then adjusted to the initial concentration with water.
[0018] Compared with the prior art, the present invention has the following significant beneficial effects:
[0019] The stable production method of the antioxidant butyl hydroxyanisole of the present invention can stably control the reaction activity and selectivity of the acid catalyst after continuous multiple applications, reduce side reactions, improve the total product yield, reduce costs, and reduce solid waste emissions. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 The present invention is a process flow chart of the stable production method of the antioxidant butylated hydroxyanisole.
[0021] Figure 2 It is a gas chromatogram of the composition of the upper layer reactant of Example 1 of the present invention.
[0022] Figure 3 It is a gas chromatogram of the composition of the upper layer reactants of Example 2 of the present invention.
[0023] Figure 4 It is a gas chromatogram of the composition of the upper layer reactant of Example 3 of the present invention.
[0024] Figure 5 It is a gas chromatogram of the composition of the upper layer reactant of Example 4 of the present invention.
[0025] Figure 6 It is a gas chromatogram of the composition of the upper layer reactant of Example 5 of the present invention.
[0026] Figure 7 It is a gas chromatogram of the composition of the upper layer reactants of Example 6 of the present invention.
[0027] Figure 8 It is a gas chromatogram of the composition of the upper layer reactant of Example 7 of the present invention.
[0028] Fig. 9 It is a gas chromatogram of the composition of the upper layer reactant of Example 8 of the present invention. DETAILED DESCRIPTION
[0029] In order to better understand the technical content of the present invention, specific embodiments are given and described as follows in conjunction with the accompanying drawings.
[0030] Various aspects of the present invention are described in this disclosure with reference to the accompanying drawings, in which many illustrative embodiments are shown. The embodiments of the present disclosure are not necessarily intended to include all aspects of the present invention. It should be understood that the various concepts and embodiments introduced above, as well as those described in more detail below, can be implemented in any of many ways.
[0031] In the actual industrial production process of BHA, considering the cost factors, the catalyst will be recovered and directly used in the production of the next batch, which is called direct application in production. The catalyst does not participate in the reaction, but there will be losses in the recovery process. Therefore, theoretically, with the continuous direct application of the catalyst, under the same reaction conditions, the reaction rate will gradually decrease, which will not affect the reaction selectivity.
[0032] However, in the actual production process, when an acidic catalyst is applied to the alkylation reaction, it is found that under the same reaction conditions, the reaction rate gradually increases, while the reaction selectivity gradually decreases, and the by-product impurity di-tert-butyl hydroxyanisole increases sharply, ultimately leading to a decrease in the yield of the main product BHA.
[0033] After a large number of experimental studies and analytical verifications, it was found that the reaction product contained a certain amount of by-product tert-butanol, and the concentration of the recovered acid continued to increase with the number of applications. Therefore, it was judged that isobutylene under the action of the acid catalyst underwent a certain amount of hydration side reaction to generate tert-butanol and consume a certain amount of water, resulting in an increase in the concentration of the acid catalyst. The final result was that with the continuous application of the recovered acid solution, the reaction rate gradually increased, while the reaction selectivity gradually decreased.
[0034] Therefore, the present invention constructs a stable production method of an antioxidant butyl hydroxyanisole, wherein p-hydroxyanisole is heated to a reaction temperature in the presence of an acidic catalyst and a solvent, and then isobutylene is introduced for alkylation reaction. After the reaction is completed, the acid phase catalyst is separated and recovered by a separating funnel, and the oil phase is distilled to recover unreacted raw materials, finished BHA and by-product impurities. The recovered acid phase catalyst is measured and analyzed for concentration, and then diluted with water to an initial concentration and then used for the next batch of reactions. Since there is a certain loss in each acid recovery, the amount of acid lost in the recovery process needs to be supplemented after each 5 to 6 times of use, and the concentration of the supplemented acid is the same as the initial acid concentration.
[0035] Combination Figure 1 As shown, in an exemplary embodiment of the present invention, a stable production method of an antioxidant butylated hydroxyanisole is provided, comprising the following steps:
[0036] S1, p-hydroxyanisole, an acidic catalyst and a solvent are mixed, heated to a reaction temperature, and then isobutylene is introduced to carry out an alkylation reaction to a reaction end point;
[0037] S2. After the reaction is completed, the acid catalyst is separated and recovered, and the oil phase is distilled to recover the unreacted raw materials, the finished product butyl hydroxyanisole and the by-product impurities;
[0038] S3, repeating steps S1 and S2 to produce the next batch of butylated hydroxyanisole until the required amount of butylated hydroxyanisole is obtained;
[0039] Among them, starting from the second batch, the current batch of acidic catalysts all use the acidic catalysts recovered from the previous batch and adjusted to the initial concentration. Moreover, after each use of the recovered acidic catalyst for 5 to 6 times, the mass of the recovered acidic catalyst is supplemented to be equal to the initial mass, and the concentration is adjusted to the same as the initial concentration, and then used for the production of the next batch, thereby smoothly controlling the reaction rate and selectivity in the production process.
[0040] As optional examples, the acidic catalyst includes an aqueous solution of sulfuric acid, hydrochloric acid, p-toluenesulfonic acid, or phosphoric acid.
[0041] As an optional example, the concentration of the acid catalyst is 60-85 wt.%.
[0042] In a more preferred example, the acidic catalyst is an aqueous solution of phosphoric acid with a concentration of 65-75 wt.%.
[0043] As optional examples, the solvent includes toluene, xylene, MIBK or cyclohexanone.
[0044] In a more preferred embodiment, the solvent is xylene.
[0045] As an optional example, in step S1, the ratio of p-hydroxyanisole, acidic catalyst and solvent is 0.25 mol: (30-50) g: (60-120) mL.
[0046] It is understandable that the hydroxyanisole, acidic catalyst and solvent in the alkylation reaction can be adjusted according to actual conditions, and stirring is used throughout the alkylation reaction. The alkylation reaction is a prior art in the art and will not be described in detail herein.
[0047] As an optional example, in step S1, the reaction temperature is 60-100°C, and particularly preferably 75-85°C.
[0048] As an optional example, in step S1, the reaction time of the alkylation reaction is 4 to 7 hours, and particularly preferably 5 to 6 hours.
[0049] As an optional example, in step S2, the lower layer of acidic catalyst is recovered by liquid-liquid stratification, and the concentration of the recovered acidic catalyst is analyzed by acid-base titration method and then adjusted to the initial concentration with water.
[0050] It can be understood that the acid-base titration method is a common method in the art, and can be performed, for example, according to the GB / T 2091-2008 method.
[0051] As an optional example, the oil phase is recovered as the reaction raw material, the finished product butyl hydroxyanisole and the by-product impurities through distillation.
[0052] It is understandable that the recovery of various substances from the oil phase by distillation is a prior art, and those skilled in the art know how to handle it.
[0053] For better understanding, the present invention is further described below in conjunction with several specific examples, but the preparation process is not limited thereto, and the content of the present invention is not limited thereto.
[0054] Unless otherwise specified, the materials in the examples were prepared according to existing methods or directly purchased from the market.
[0055] Examples 1-4
[0056] Add 31.0g MEHQ, 50g 70% phosphoric acid, and 80mL xylene into a 500mL four-necked bottle, heat to 80°C, add isobutylene to stir and react, transfer the reaction mixture into a separating funnel for stratification, and directly apply the lower phosphoric acid to the next batch after metering, apply it 3 times, and analyze the composition of the upper reactant of each batch by gas chromatography (area normalization method, using capillary column, hydrogen flame detector, high-purity nitrogen carrier gas). The specific reaction conditions and analysis results are shown in Table 1.
[0057] Table 1
[0058]
[0059] Combination Figure 2-5 As shown in Table 1, with the increase in the number of direct applications of the recovered acidic catalyst, the acid concentration gradually increases. When the reaction time gradually decreases, the residual amount of raw materials (MEHQ) gradually decreases, the product gradually increases, the increase in by-products is more obvious, and the yield of BHA decreases.
[0060] Embodiment 5-8
[0061] A 500mL four-necked bottle was added with 1.0g MEHQ3, 50g 70% phosphoric acid and 80mL xylene, and the temperature was raised to 80°C. Isobutylene was passed through the bottle to stir and react. The reaction time was fixed at 5 hours. After the reaction was completed, the reaction mixture was transferred into a separating funnel for stratification. The phosphoric acid in the lower layer was measured and analyzed for concentration. The calculated amount of water was added to dilute the phosphoric acid concentration to 70% and then applied to the next batch. The application was repeated 3 times, and the composition of the upper layer reactants of each batch was analyzed by gas chromatography (area normalization method, using a capillary column, a hydrogen flame detector, and a high-purity nitrogen carrier gas). The specific reaction conditions and analysis results are shown in Table 2.
[0062] Table 2
[0063]
[0064] Combination Figure 6-9 As shown in Table 2, before each application of the recovered acidic catalyst, the concentration was measured and analyzed, and a calculated amount of water was added to stabilize the concentration of the acidic catalyst at the initial concentration during application. The results showed that within the same reaction time, the residual amount of the raw material (MEHQ), the product (BHA) and the by-product impurity content were basically stable, and the reaction activity and selectivity were stably controlled.
[0065] From the above results, it can be seen that the production of BHA by the method of the present invention can better suppress the fluctuation of reaction rate and reaction selectivity in the production process of antioxidant BHA, control the reaction activity and selectivity steadily, reduce side reactions, improve the total yield of the product, reduce costs, and reduce solid waste emissions.
[0066] Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. A person with ordinary knowledge in the technical field to which the present invention belongs may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the definition of the claims.
Claims
1. A stable production method of antioxidant butylated hydroxyanisole, characterized in that: The following steps are involved: S1, p-hydroxyanisole, an acidic catalyst and a solvent are mixed, heated to a reaction temperature, and then isobutylene is introduced to carry out an alkylation reaction to a reaction end point; S2. After the reaction is completed, the acid catalyst is separated and recovered, and the oil phase is distilled to recover the unreacted raw materials, the finished product butyl hydroxyanisole and the by-product impurities; S3, repeating steps S1 and S2 to produce the next batch of butylated hydroxyanisole until the required amount of butylated hydroxyanisole is obtained; Among them, starting from the second batch, the current batch of acidic catalysts all use the acidic catalysts recovered from the previous batch and adjusted to the initial concentration. Moreover, after each use of the recovered acidic catalyst for 5 to 6 times, the mass of the recovered acidic catalyst is supplemented to be equal to the initial mass, and the concentration is adjusted to the same as the initial concentration, and then used for the production of the next batch, thereby smoothly controlling the reaction rate and selectivity in the production process.
2. The stable production method of the antioxidant butylated hydroxyanisole according to claim 1, characterized in that: The acidic catalyst includes an aqueous solution of sulfuric acid, hydrochloric acid, p-toluenesulfonic acid or phosphoric acid.
3. The stable production method of the antioxidant butylated hydroxyanisole according to claim 1 or 2, characterized in that: The concentration of the acid catalyst is 60-85 wt.%.
4. The stable production method of the antioxidant butylated hydroxyanisole according to claim 1, characterized in that: The solvent includes toluene, xylene, MIBK or cyclohexanone.
5. The stable production method of the antioxidant butylated hydroxyanisole according to claim 1, characterized in that: In the step S1, the ratio of p-hydroxyanisole, acidic catalyst and solvent is 0.25 mol: (30-50) g: (60-120) mL.
6. The stable production method of the antioxidant butylated hydroxyanisole according to claim 1, characterized in that: In the step S1, the reaction temperature is 60-100°C.
7. The stable production method of the antioxidant butylated hydroxyanisole according to claim 1, characterized in that: In the step S1, the reaction time of the alkylation reaction is 4 to 7 hours.
8. The stable production method of the antioxidant butylated hydroxyanisole according to claim 1, characterized in that: In the step S2, the lower layer of acidic catalyst is recovered by liquid-liquid stratification, and the concentration of the recovered acidic catalyst is analyzed by acid-base titration method and then adjusted to the initial concentration with water.