A method for synthesizing isooctanol benzoate using a composite catalyst

Abstract

The application discloses a method for synthesizing isooctanol benzoate by using a composite catalyst, and comprises the following steps: mixing isooctanol, the composite catalyst and benzoic acid, and heating and stirring, then increasing the temperature to 140-210 DEG C, carrying out esterification reaction for 5-7 hours, after the esterification reaction is completed, carrying out decoloration, neutralization, water washing, dehydration and dealcoholization, filtering, and cooling to obtain isooctanol benzoate. The application has the beneficial effects that by using the composite catalyst, the color number of the product can be reduced, the reaction speed can be accelerated, the isooctanol utilization rate can be improved, and the esterification reaction efficiency is improved; the process is simple, the production cycle is short, the product yield is high, the color number is small, energy is saved, the environment is protected, and industrialization is easy to realize.

Description

Technical Field

[0001] This invention relates to the field of organic synthesis technology, and in particular to a method for synthesizing isooctanol benzoate using a composite catalyst. Background Technology

[0002] Isooctyl benzoate is a colorless, transparent, oily substance insoluble in water but soluble in many alcohols, ketones, esters, and other solvents. It has low viscosity and can be used in rubber, resins, coatings, and polyurethane products. As a plasticizer, it has strong solvent properties, low viscosity, and excellent flowability. This product is an environmentally friendly additive, considered non-toxic, and can be widely used in consumer products such as coatings and plastic products.

[0003] Esters can be synthesized through esterification, transesterification, and acyl chloride condensation, among others. Esterification is the most common method. The esterification synthesis of isooctanol benzoate uses isooctanol and benzoic acid as raw materials. In the esterification reaction, isooctanol and benzoic acid react slowly at low temperatures, resulting in long reaction times and low conversion rates. This makes it difficult to separate isooctanol and benzoate, leading to low raw material utilization and the need for separation via a fractionating column. Consequently, production costs are high and process conditions are complex. Summary of the Invention

[0004] In view of this, it is necessary to provide a method for synthesizing isooctanol benzoate using a composite catalyst to solve the technical problems of high synthesis difficulty, low raw material utilization and high production cost in the prior art.

[0005] This invention provides a method for synthesizing isooctanol benzoate using a composite catalyst, comprising the following steps:

[0006] The isooctanol, composite catalyst and benzoic acid are mixed and heated and stirred, a protective gas is introduced, and then the temperature is raised to 140-210°C. The esterification reaction is carried out for 5-7 hours. After the esterification reaction is completed, the product is decolorized, neutralized, washed with water, dehydrated and de-alcoholized, filtered and cooled to obtain isooctanol benzoate.

[0007] Preferably, the molar ratio of isooctanol to benzoic acid is 1:1.05-1.1.

[0008] Preferably, the composite catalyst accounts for 0.6%-1.2% of the total mass of isooctyl alcohol and benzoic acid.

[0009] Preferably, the composite catalyst comprises zirconium carbonate and a porous zeolite catalyst treated with zinc methanesulfonate.

[0010] Preferably, the porous zeolite is 60-80 mesh, and the mass ratio of the zinc methanesulfonate-treated porous zeolite catalyst to zirconium carbonate is 1-4:1.

[0011] Preferably, the method for treating porous zeolite catalysts with zinc methanesulfonate is as follows:

[0012] Distilled water and methanesulfonic acid were mixed and added to a reaction flask. Zinc oxide was added, and the mixture was stirred and heated under reflux. The mixture was filtered while hot, washed, and the filtrates were combined, evaporated to dryness, and dried at low temperature to obtain zinc methanesulfonate. Zinc methanesulfonate was dissolved in distilled water at a concentration of 100 g / L-200 g / L. Porous zeolite was added and stirred at 80 °C. After heating and stirring were stopped, the mixture was allowed to stand at room temperature, filtered, and dried to obtain a porous zeolite catalyst treated with zinc methanesulfonate.

[0013] Preferably, the esterification reaction includes a primary esterification reaction and a secondary esterification reaction;

[0014] The temperature of the first esterification reaction is 140-160℃, and the reaction time is 2-3 hours.

[0015] The secondary esterification reaction is carried out at a temperature of 200-210℃ for 2-4 hours.

[0016] Preferably, the decolorization process is as follows: after the esterification reaction is completed, heating is stopped, the material is transferred to a water washing tank, the material temperature is reduced to 70-85℃, a strong oxidant is added, and the material is kept at 100-120℃ for 0.5-1h.

[0017] Preferably, the neutralization process is as follows: after the material is cooled to 80-95℃, alkali solution is slowly added to adjust the pH of the system to above 9, and the system temperature is maintained at 90-100℃. The mixture is stirred for 0.5-1h, allowed to stand for 0.5-1h to separate into layers, the aqueous alkaline solution is extracted, and the oil phase material is retained.

[0018] Preferably, the process of washing, dehydration and dealcoholization is as follows: maintain the system temperature at 85℃-95℃, add water, stir for 0.5-1h, let stand for 0.5-1h to separate the phases, extract the aqueous phase, retain the oil phase, and then heat to 140-150℃ and distill under reduced pressure for 4-6h to dehydrate and dealcoholize.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] This invention utilizes a composite catalyst and vacuum distillation to reduce the product color number, accelerate the reaction rate, increase the utilization rate of isooctanol, and improve the esterification reaction efficiency. The invention features a simple process, short production cycle, high product yield, low color number, energy saving, and environmental friendliness, making it easily industrializable.

[0021] Furthermore, this invention utilizes a composite catalyst formed by combining zirconium carbonate and a porous zeolite catalyst treated with zinc methanesulfonate. This process eliminates the need for organic solvents, simplifies post-processing, reduces product costs, is environmentally friendly, minimizes safety hazards, improves the reaction efficiency of isooctanol and benzoic acid, increases the reaction rate, reduces the isooctanol content in the product, and increases the yield. The porous zeolite treated with zinc methanesulfonate enhances catalytic efficiency, resulting in a better product color, higher purity, and extended reaction vessel lifespan. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0023] This invention provides a method for synthesizing isooctanol benzoate using a composite catalyst, comprising the following steps:

[0024] S1. Weigh 50g of distilled water and mix it with 0.4mol of methanesulfonic acid in a reaction flask. Slowly add 0.2mol of zinc oxide and heat under reflux for 2 hours with stirring. Filter while hot, wash, combine the filtrates, evaporate to dryness, and dry at low temperature to obtain zinc methanesulfonate. Dissolve zinc methanesulfonate in distilled water (concentration 100g / L-200g / L), add a certain proportion of porous zeolite (60-80 mesh) (weight ratio of 1:5-1:8 to the solution), stir at 80℃ for 1.5 hours, stop heating and stirring, let stand at room temperature for 10 hours, filter and dry to obtain porous zeolite catalyst treated with zinc methanesulfonate.

[0025] S2. Mix isooctanol, composite catalyst and benzoic acid, introduce nitrogen gas, and then raise the temperature to 140-210℃ for esterification reaction for 5-7 hours. After the esterification reaction is completed, decolorize, neutralize, wash with water, dehydrate and remove alcohol, filter and cool to obtain isooctanol benzoate.

[0026] This invention utilizes a composite catalyst and vacuum distillation to reduce the product color number, accelerate the reaction rate, increase the utilization rate of isooctanol, and improve the esterification reaction efficiency. The invention features a simple process, short production cycle, high product yield, low color number, energy saving, and environmental friendliness, making it easily industrializable.

[0027] Furthermore, this invention utilizes a composite catalyst formed by combining zirconium carbonate and a porous zeolite catalyst treated with zinc methanesulfonate. This process eliminates the need for organic solvents, simplifies post-processing, reduces product costs, is environmentally friendly, minimizes safety hazards, improves the reaction efficiency of isooctanol and benzoic acid, increases the reaction rate, reduces the isooctanol content in the product, and increases the yield. The porous zeolite treated with zinc methanesulfonate enhances catalytic efficiency, resulting in a better product color, higher purity, and extended reaction vessel lifespan.

[0028] Specifically, by using treated porous zeolite in combination with zirconium carbonate as a composite catalyst, without the use of organic solvents, the post-processing is simple, which can reduce product costs, is environmentally friendly, has fewer safety hazards, improves the reaction efficiency of isooctyl alcohol and benzoic acid, and increases the reaction rate.

[0029] Furthermore, porous zeolite treated with zinc methanesulfonate can improve catalytic efficiency, resulting in better product color, higher purity, and extended reaction vessel lifespan.

[0030] It is understandable that strictly controlling the feeding ratio of isooctanol and benzoic acid is beneficial to improving product yield. In this embodiment, the molar ratio of isooctanol to benzoic acid is 1:1.05-1.1. By controlling the feeding ratio of isooctanol to benzoic acid within this range, the present invention can increase the ester content and effectively reduce the isooctanol content in isooctanol-benzoic acid; at the same time, excessive water addition will also significantly reduce product yield.

[0031] In this embodiment, the total amount of the composite catalyst accounts for 0.6%-1.2% of the total mass of isooctanol and benzoic acid; the catalyst consists of two types: porous zeolite treated with zinc methanesulfonate and zirconium carbonate. This invention, by employing a composite catalyst, can increase the reaction rate, reduce the isooctanol content in the product, and improve the yield. Furthermore, when used in combination, the mass ratio of porous zeolite with different pore sizes treated with zinc methanesulfonate to zirconium carbonate is (1-4):1.

[0032] In this embodiment, the esterification reaction includes a primary esterification reaction and a secondary esterification reaction; the temperature of the primary esterification reaction is 140-160℃, and the reaction time is 2-3 hours; the temperature of the secondary esterification reaction is 200-210℃, and the reaction time is 2-4 hours. This invention, by controlling the temperature of the esterification reaction, can increase the esterification reaction rate and lower the reaction temperature. If the reaction temperature is lower than the controlled temperature, the reaction will be difficult to occur, reducing the product reaction rate and esterification rate; if the reaction temperature is too high, it will increase the product color, cause violent reactions posing safety hazards, and reduce the product's lifespan. In some specific embodiments of this invention, the temperature of the primary esterification reaction is 140-160℃, and the reaction time is 2-3 hours; the temperature of the secondary esterification reaction is 200-210℃, and the reaction time is 2-4 hours.

[0033] In this embodiment, the decolorization process is as follows: after the esterification reaction is completed, heating is stopped, the material is transferred to a water washing tank, the material temperature is reduced to 70-85℃, a strong oxidizing agent is added, and the temperature is maintained at 100-120℃ for 0.5-1 hour. Further, the strong oxidizing agent is hydrogen peroxide.

[0034] In this embodiment, the neutralization process is as follows: the material is cooled to 80-95°C, an alkaline solution is slowly added to adjust the pH of the system to above 9, and the system temperature is maintained at 80-100°C. The mixture is stirred for 0.5-1 hour, allowed to stand for 0.5-1 hour to separate into layers, the aqueous alkaline solution is extracted, and the oil phase material is retained.

[0035] In this embodiment, the process of washing, dehydration and dealcoholization is as follows: keep the system temperature above 80°C, add water, stir for 0.5 to 1 hour, let stand for 0.5 to 1 hour to separate the phases, extract the aqueous phase, retain the oil phase, heat to 140-150°C, and distill under reduced pressure for 4-6 hours to dehydrate and dealcoholize.

[0036] Example 1

[0037] 520.92g of isooctyl alcohol, 512.91g of benzoic acid, and a composite catalyst (3.10g of methanesulfonic acid-treated zeolite and 3.10g of zirconium carbonate) were added to the reactor, and nitrogen gas was introduced. The temperature was raised to 150℃ to start the first step of esterification reaction, and the temperature was maintained for 3 hours. After the reaction was completed, a second esterification reaction was carried out, and the temperature was raised to 205-210℃ and maintained for 4 hours. After the reaction is complete, heating is stopped, and the material is transferred to a water washing vessel. When the material temperature is reduced to about 80-85℃, hydrogen peroxide is added, and the mixture is kept at 100-105℃ for 1 hour. When the material temperature is reduced to about 80-85℃, alkali solution is slowly added to adjust the pH of the system to above 9, and the system temperature is maintained at 90℃. The mixture is stirred for 30 minutes, allowed to stand for 30 minutes to separate into layers, and the aqueous alkaline solution is extracted, while the oil phase is retained. The system temperature is maintained above 80℃, water is added, and the mixture is stirred for 30 minutes. The mixture is allowed to stand for 30 minutes to separate into layers, and the aqueous phase is extracted, while the oil phase is retained. The mixture is then heated to about 140℃ and subjected to vacuum distillation to remove water and alcohol for 4 hours. After filtration and cooling, 953.19g of isooctanol benzoate is obtained, with a yield of 92.2%, a main content of 96.47%, and is a colorless and transparent liquid with an acidity (calculated as benzoic acid) of 0.05%, an APHA color number of 25, a water content of 0.05%, and a residual isooctanol content of 0.12%.

[0038] Example 2

[0039] 520.92g of isooctanol, 512.91g of benzoic acid, and a composite catalyst (9.92g of methanesulfonic acid-treated zeolite and 2.48g of zirconium carbonate) were added to a reactor. Nitrogen gas was introduced, and the temperature was raised to 160℃ to begin the first step of esterification reaction. The reaction was held at this temperature for 3 hours. After the reaction was completed, the temperature was raised to 205-210℃ and held for 4 hours. After the reaction was completed, heating was stopped, and the material was transferred to a water washing vessel. Nitrogen gas was continued to be introduced, and the material temperature was lowered to about 80-85℃. Hydrogen peroxide was added, and the temperature was held at 110-115℃ for 1 hour. When the material temperature was lowered to about 80-85℃, alkali solution was slowly added to adjust the pH of the system to above 9, and the system temperature was maintained at 90℃. The mixture was stirred for 45 minutes, allowed to stand for 45 minutes to separate into layers, and the aqueous phase of alkali was extracted. The aqueous solution was prepared, retaining the oil phase. The system temperature was kept above 80℃, water was added, and the mixture was stirred for 45 minutes. After standing for 45 minutes to separate the layers, the aqueous phase was extracted, and the oil phase was retained. The mixture was then heated to about 150℃ and subjected to vacuum distillation to remove water and alcohol for 6 hours. After filtration and cooling, 979.04 g of isooctanol benzoate was obtained, with a yield of 94.7% and a main content of 99.12%. The product was a pale yellow or colorless transparent liquid with an acidity (calculated as benzoic acid) of 0.07%, an APHA color number of 35, a water content of 0.03%, and a residual isooctanol content of 0.05%.

[0040] Example 3

[0041] 520.92g of isooctyl alcohol, 537.33g of benzoic acid, and a composite catalyst (3.17g of methanesulfonic acid-treated zeolite and 3.17g of zirconium carbonate) were added to the reactor. Nitrogen gas is introduced, and the temperature is raised to 160℃ to begin the first step of esterification reaction. This temperature is maintained for 2 hours. After the reaction, the temperature is further increased to 200℃ and maintained for 3 hours. After the reaction is complete, heating is stopped, and the material is transferred to a water washing vessel. Nitrogen gas is continued to be introduced, and the material temperature is lowered to approximately 80℃. Hydrogen peroxide is then added, and the temperature is maintained at 115-120℃ for 1 hour. When the material temperature drops to approximately 80-85℃, alkali solution is slowly added to adjust the system pH to above 9, and the system temperature is maintained at 90℃. The mixture is stirred for 1 hour, allowed to stand for 1 hour to separate into layers, and the aqueous alkaline solution is extracted, retaining the oil phase. The system temperature is maintained above 85℃, water is added, and the mixture is stirred for 1 hour. The mixture is allowed to stand for 1 hour to separate into layers, and the aqueous layer is extracted, retaining the oil phase. The mixture is then heated to approximately 140℃ and subjected to vacuum distillation for 5 hours to remove water and alcohol. After filtration and cooling, 948.2g of isooctanol benzoate was obtained, with a yield of 89.6% and a main content of 97.35%. The product is a colorless and transparent liquid with an acidity (calculated as benzoic acid) of 0.06%, APHA color number 20, water content of 0.03%, and residual isooctanol content of 0.09%.

[0042] Example 4

[0043] Compared with Example 3, the only difference is that the composite catalyst (10.16g of zeolite treated with methanesulfonic acid and 2.54g of zirconium carbonate) was post-treated at 150°C for dehydration and deethanolination for 5 hours, and the rest is the same as Example 3.

[0044] After filtration and cooling, 966.16 g of the finished product isooctyl benzoate was obtained, with a yield of 91.3% and a main content of 98.31%. The product is a pale yellow or colorless transparent liquid with an acidity (calculated as benzoic acid) of 0.04%, APHA color number 35, water content of 0.03%, and residual isooctyl alcohol content of 0.06%.

[0045] Comparative Example 1

[0046] The difference compared to Example 2 is that only 12.41 g of zirconium carbonate was used as the catalyst. The subsequent process was exactly the same as in Example 2.

[0047] After filtration and cooling, 887.03g of isooctanol benzoate was obtained, with a yield of 85.8% and a main content of 93.54%. The product is a pale yellow liquid with an acidity (calculated as benzoic acid) of 0.06%, an APHA color number of 50, and a residual isooctanol content of 0.09%.

[0048] Comparative Example 2

[0049] Compared with Example 3, the difference is that zinc methanesulfonate was dissolved in distilled water at a concentration of 300 g / L during catalyst preparation, while the rest is the same as in Example 3.

[0050] After filtration and cooling, 970.42 g of the finished product isooctanol benzoate was obtained, with a yield of 91.7% and a main content of 97.81%. The product is a yellow transparent liquid with an acidity (calculated as benzoic acid) of 0.08%, an APHA color number of 80, a water content of 0.04%, and a residual isooctanol content of 0.14%.

[0051] Comparative Example 3

[0052] The difference from Example 3 is that only 6.35g of zeolite was treated with zinc methanesulfonate as catalyst, while the rest was the same as in Example 3.

[0053] After filtration and cooling, 872g of the finished product, isooctanol benzoate, was obtained, with a yield of 82.4% and a main content of 89.62%. The product is a yellow transparent liquid with an acidity (calculated as benzoic acid) of 0.05%, an APHA color number of 100, a water content of 0.05%, and a residual isooctanol content of 0.11%.

[0054] Based on Examples 1-4 and Comparative Examples 1-3, the above experimental results can be listed in Table 1.

[0055]

[0056] Comparative Analysis 1:

[0057] Based on Examples 1-2, it can be seen that the octanol benzoate synthesized in Example 2 has a high yield and main content, and the lowest residual isooctyl alcohol content. Therefore, it can be concluded that a high content of zeolite treated with methanesulfonic acid can improve the yield and content of octanol benzoate.

[0058] Comparative Analysis 2:

[0059] Based on Examples 3-4, it can be seen that the yield and main content of octanol benzoate obtained in Example 4 are higher than those in Example 3, while the residual isooctyl alcohol content is lower than that in Example 3. This indicates that a higher temperature can improve the de-alcoholization effect during dehydration and de-alcoholization.

[0060] Comparative Analysis 3:

[0061] Combining Example 2 and Comparative Example 1, it can be concluded that the octanol benzoate synthesized in Example 2 has a high yield and main content, and the lowest residual isooctanol content. Therefore, it can be concluded that using only zirconium carbonate as a catalyst, compared with the composite catalyst used in Example 2, the yield and main content of octanol benzoate in Comparative Example 1 are reduced.

[0062] Comparative Analysis 4:

[0063] Combining Example 3 and Comparative Example 2, the difference in Comparative Example 2 lies in the fact that the concentration of methylbenzenesulfonic acid was increased to 300 g / L during catalyst preparation, followed by zeolite treatment. That is, Comparative Example 2 only increased the concentration of zinc methylbenzenesulfonate. From the above data, it can be concluded that the yield and main content of octanol benzoate synthesized in Example 3 are lower than those in Comparative Example 2, but the residual isooctanol content is also lower. This indicates that by simply increasing the concentration of zinc methylbenzenesulfonate dissolved in distilled water without increasing the amount of zeolite used, the residual isooctanol content increases compared to Example 3. In other words, if a certain proportion of porous zeolite (60-80 mesh) (weight ratio of 1:5-1:8 to the solution) is not added according to a concentration ratio of 100 g / L-200 g / L for the synthesis of porous zeolite catalysts, the residual isooctanol content will increase, significantly increasing the product color.

[0064] Comparative Analysis 5:

[0065] Based on Example 3 and Comparative Example 3, it can be concluded that the yield and main content of octanol benzoate synthesized in Example 3 are higher than those in Comparative Example 3, while the residual isooctyl alcohol content is lower than that in Comparative Example 3. Therefore, it can be concluded that if zirconium carbonate is not added, the catalytic efficiency of the composite catalyst will be greatly reduced, and the amount of octanol benzoate synthesized will be reduced.

[0066] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for synthesizing isooctanol benzoate using a composite catalyst, characterized in that, Includes the following steps: Isooctanol, a composite catalyst, and benzoic acid are mixed and heated with stirring. The molar ratio of isooctanol to benzoic acid is 1:1.05-1.

1. The composite catalyst accounts for 0.6%-1.2% of the total mass of isooctanol and benzoic acid. A protective gas is introduced, and then the temperature is raised to 140-210℃. The esterification reaction is carried out for 5-7 hours. After the esterification reaction is completed, the product is decolorized, neutralized, washed with water, dehydrated and de-alcoholized, filtered, and cooled to obtain isooctanol benzoate. The composite catalyst includes zirconium carbonate and a porous zeolite catalyst treated with zinc methanesulfonate. The porous zeolite is 60-80 mesh, and the mass ratio of the zinc methanesulfonate-treated porous zeolite catalyst to zirconium carbonate is 1-4:

1.

2. The method for synthesizing isooctanol benzoate according to claim 1, characterized in that, The method for treating porous zeolite catalysts with zinc methanesulfonate is as follows: Distilled water and methanesulfonic acid were mixed and added to a reaction flask. Zinc oxide was added, and the mixture was stirred and heated under reflux. The mixture was filtered while hot, washed, and the filtrates were combined, evaporated to dryness, and dried at low temperature to obtain zinc methanesulfonate. Zinc methanesulfonate was dissolved in distilled water at a concentration of 100 g / L-200 g / L. Porous zeolite was added and stirred at 80 °C. After heating and stirring were stopped, the mixture was allowed to stand at room temperature, filtered, and dried to obtain a porous zeolite catalyst treated with zinc methanesulfonate.

3. The method for synthesizing isooctanol benzoate according to claim 1, characterized in that, The esterification reaction includes a primary esterification reaction and a secondary esterification reaction; The temperature of the first esterification reaction is 140-160℃, and the reaction time is 2-3 hours. The secondary esterification reaction is carried out at a temperature of 200-210℃ for 2-4 hours.

4. The method for synthesizing isooctanol benzoate according to claim 1, characterized in that, The decolorization process is as follows: after the esterification reaction is completed, heating is stopped, the material is transferred to a water washing tank, the material temperature is reduced to 70-85℃, a strong oxidant is added, and the material is kept at 100-120℃ for 0.5-1h.

5. The method for synthesizing isooctanol benzoate according to claim 1, characterized in that, The neutralization process is as follows: after the material cools down to 80-95℃, slowly add alkaline solution to adjust the pH of the system to above 9, and keep the system temperature at 90-100℃. Stir for 0.5-1h, let it stand for 0.5-1h to separate the layers, extract the aqueous alkaline solution, and retain the oil phase material.

6. The method for synthesizing isooctanol benzoate according to claim 1, characterized in that, The water washing, dehydration and dealcoholization process is as follows: maintain the system temperature at 85℃-95℃, add water, stir for 0.5~1h, let stand for 0.5~1h to separate the phases, extract the aqueous phase, retain the oil phase, and then heat to 140-150℃ and distill under reduced pressure for 4-6h to dehydrate and dealcoholize.

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