Method for preparing p-tert-butyl methyl benzoate
Technical Field
The invention relates to a method for preparing methyl p-tert-butylbenzoate, in particular to a method for preparing methyl p-tert-butylbenzoate under the action of a green acid catalyst.
Background
The p-tert-butyl methyl benzoate is used as an important organic synthesis intermediate and a medical intermediate, and is widely applied to the industries of chemical synthesis, cosmetics, medicines, essences, spices and the like. The annual demand of the market is very large, so that the research on the synthesis of p-tert-butyl methyl benzoate has important value.
The production method of methyl p-tert-butylbenzoate is mainly characterized by that under the catalytic action of acid catalyst the esterification reaction is made between p-tert-butylbenzoic acid and methyl alcohol. The traditional synthesis method of p-tert-butyl methyl benzoate adopts concentrated sulfuric acid as a catalyst to directly catalyze esterification reaction, although the yield is high, organic matters are easy to dehydrate and carbonize, the reaction time is long, and the separation post-treatment is difficult. And the method has great influence on environmental pollution, large wastewater discharge amount and serious corrosion to equipment. Yet another approach is to use anhydrous AlCl3、FeCl3Titanium sulfate is used as a catalyst to synthesize p-tert-butyl methyl benzoate, the method needs to adopt a distillation water separation process to control reflux reaction, although the conversion rate is high and the operation is simple, the catalyst used in the method is easy to hydrolyze, the reaction needs to be carried out under strict anhydrous condition, and continuous water separation is needed in the reaction process. Therefore, the problem to be solved at present is to find a green acidic catalyst which has high activity, good catalyst stability and easy product separation for preparing the p-tert-butyl methyl benzoate.
Disclosure of Invention
The invention aims to provide a novel method for preparing methyl p-tert-butylbenzoate by using methanol and p-tert-butylbenzoate as raw materials and carrying out esterification reaction under the action of a catalyst which is a sulfonic acid resin. The method has the advantages of good catalyst stability, high reaction activity, environmental friendliness, no equipment corrosion, easy product separation, recyclable catalyst and the like.
The method specifically comprises the following steps: mixing methanol, p-tert-butyl benzoic acid and sulfonic acid resin, heating, carrying out esterification reaction, carrying out centrifugal separation, and carrying out rotary evaporation separation on an upper layer product to obtain p-tert-butyl methyl benzoate;
wherein, the lower layer after centrifugal separation is a sulfonic acid resin catalyst.
The sulfonic acid resin catalyst contains SO3The resin catalyst with H functional group is preferably one or two of polystyrene sulfonic acid resin and perfluoro sulfonic acid resin.
Among them, the resin catalyst containing sulfonic acid functional group is easy to separate.
The sulfonic acid resin catalyst is solid, and after the reaction is finished, the product and the catalyst are easy to separate, so that the sulfonic acid resin catalyst can be repeatedly recycled.
Wherein the present invention is not strictly limited by anhydrous conditions, so that methanol can participate in the reaction in any concentration state, and pure methanol is preferred.
The invention further provides a method which specifically adopts the following steps:
1) mixing methanol, p-tert-butyl benzoic acid and sulfonic acid resin, and stirring for 0.1-15 h at the temperature of 50-200 ℃ and the pressure of 0.1-4 Mpa to react to obtain a reaction solution;
2) and (2) carrying out centrifugal separation on the reaction liquid obtained in the step 1), and carrying out rotary evaporation treatment on the upper-layer crude product to obtain the p-tert-butyl methyl benzoate.
And the crude product on the upper layer is subjected to rotary evaporation to remove methanol and water, and then the temperature is raised, and the target product methyl p-tert-butylbenzoate is obtained by rotary evaporation, wherein unreacted p-tert-butylbenzoic acid and methanol are recycled, and the catalyst on the lower layer is recycled.
The molar ratio of the p-tert-butyl benzoic acid to the methanol is 1: 1-1: 30, preferably 1: 8-1: 10.
The weight of the catalyst is 1-20% of the weight of the raw material, and the preferred weight is 10%.
The pressure is 0.1-4 Mpa;
the temperature is 50-200 ℃;
the reaction time is 0.1-15 h.
A further preferred embodiment of the present invention is a process for the preparation of methyl p-tert-butylbenzoate, said process comprising the steps of:
1) adding raw materials of p-tert-butyl benzoic acid and methanol in a molar ratio of 1: 8-1: 10 into a reactor, adding a polystyrene sulfonic acid resin or perfluorinated sulfonic acid resin catalyst accounting for 10% of the raw materials by weight, and stirring for 2-8 hours to react under the conditions that the temperature is 100-120 ℃ and the pressure is 1-1.6 Mpa to obtain a reaction solution;
2) carrying out centrifugal separation on the reaction liquid obtained in the step 1), and carrying out rotary evaporation treatment on an upper layer crude product to obtain p-tert-butyl methyl benzoate;
the lower layer after centrifugal separation is the catalyst which is recycled.
Another object of the present invention is to provide methyl p-tert-butylbenzoate prepared by any of the above-mentioned methods.
The method for preparing the p-tert-butyl methyl benzoate at least comprises the following advantages:
1) the adopted sulfonic acid resin catalyst has good stability and is green and environment-friendly;
2) high catalytic reaction activity, high reaction speed, relatively mild reaction conditions, low reaction requirements and easy industrial production.
3) The invention does not cause corrosion and environmental pollution of reaction equipment, is environment-friendly in the production process, and reduces the requirement on corrosion resistance of the reaction equipment;
4) after the reaction is finished, the catalyst and the product are easy to separate, and the catalyst can be recycled, thereby being beneficial to reducing the production cost.
Detailed Description
The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.
Example 1
Adding raw materials of methanol and p-tert-butyl benzoic acid with a molar ratio of 10:1 into a reactor, adding a polystyrene sulfonic acid resin catalyst with the raw material weight percentage of 10%, heating, stirring under the conditions of a reaction temperature of 100 ℃ and a reaction pressure of 1Mpa, and carrying out esterification reaction. After 8h of reaction, discharging reaction liquid, performing centrifugal separation, obtaining an upper-layer product, namely a crude product of p-tert-butyl benzoic acid methyl ester, water and a small amount of raw materials of p-tert-butyl benzoic acid and methanol, performing rotary evaporation on the upper-layer product to remove the methanol and the water firstly, and then performing rotary evaporation to obtain a target product of p-tert-butyl benzoic acid methyl ester, wherein unreacted p-tert-butyl benzoic acid and methanol are recycled, and a lower-layer catalyst is recycled. The yield of the p-tert-butyl methyl benzoate is 95 percent, and the purity is more than or equal to 99.99 percent.
Example 2
Adding raw materials of methanol and p-tert-butyl benzoic acid with a molar ratio of 10:1 into a reactor, adding a perfluorinated sulfonic acid resin catalyst with the raw material weight percentage of 10%, heating, stirring under the conditions of a reaction temperature of 120 ℃ and a reaction pressure of 1.5Mpa, and carrying out esterification reaction. After 5h of reaction, discharging reaction liquid, performing centrifugal separation, obtaining an upper-layer product, namely a crude product of p-tert-butyl benzoic acid methyl ester, water and a small amount of raw materials of p-tert-butyl benzoic acid and methanol, performing rotary evaporation on the upper-layer product to remove the methanol and the water firstly, and then performing rotary evaporation to obtain a target product of p-tert-butyl benzoic acid methyl ester, wherein unreacted p-tert-butyl benzoic acid and methanol are recycled, and a lower-layer catalyst is recycled. The yield of the p-tert-butyl methyl benzoate is 96 percent, and the purity is more than or equal to 99.99 percent.
Example 3
Adding raw materials of methanol and p-tert-butyl benzoic acid with a molar ratio of 10:1 into a reactor, adding a polystyrene sulfonic acid resin catalyst with the raw material weight percentage of 15%, heating, stirring under the conditions of a reaction temperature of 120 ℃ and a reaction pressure of 1.5Mpa, and carrying out esterification reaction. After reacting for 3h, discharging reaction liquid, centrifugally separating to obtain an upper-layer product, namely a crude product of p-tert-butyl benzoic acid methyl ester, water and a small amount of raw materials of p-tert-butyl benzoic acid and methanol, carrying out rotary evaporation on the upper-layer product to remove the methanol and the water firstly, and then carrying out rotary evaporation to obtain a target product of p-tert-butyl benzoic acid methyl ester, wherein unreacted p-tert-butyl benzoic acid and methanol are recycled, and a lower-layer catalyst is recycled. The yield of the p-tert-butyl methyl benzoate is 94 percent, and the purity is more than or equal to 99.99 percent.
Example 4
Adding raw materials of methanol and p-tert-butyl benzoic acid with a molar ratio of 10:1 into a reactor, adding a perfluorosulfonic acid resin catalyst with the raw material weight percentage of 5%, heating, stirring under the conditions of a reaction temperature of 120 ℃ and a reaction pressure of 1.5Mpa, and carrying out esterification reaction. After 8h of reaction, discharging reaction liquid, performing centrifugal separation, obtaining an upper-layer product, namely a crude product of p-tert-butyl benzoic acid methyl ester, water and a small amount of raw materials of p-tert-butyl benzoic acid and methanol, performing rotary evaporation on the upper-layer product to remove the methanol and the water firstly, and then performing rotary evaporation to obtain a target product of p-tert-butyl benzoic acid methyl ester, wherein unreacted p-tert-butyl benzoic acid and methanol are recycled, and a lower-layer catalyst is recycled. The yield of the p-tert-butyl methyl benzoate is 94 percent, and the purity is more than or equal to 99.99 percent.
Example 5
Adding raw materials of methanol and p-tert-butyl benzoic acid with a molar ratio of 10:1 into a reactor, adding a polystyrene sulfonic acid resin catalyst with the raw material weight percentage of 10%, heating, stirring under the conditions of a reaction temperature of 80 ℃ and a reaction pressure of 0.8Mpa, and carrying out esterification reaction. After 8h of reaction, discharging reaction liquid, performing centrifugal separation, obtaining an upper-layer product, namely a crude product of p-tert-butyl benzoic acid methyl ester, water and a small amount of raw materials of p-tert-butyl benzoic acid and methanol, performing rotary evaporation on the upper-layer product to remove the methanol and the water firstly, and then performing rotary evaporation to obtain a target product of p-tert-butyl benzoic acid methyl ester, wherein unreacted p-tert-butyl benzoic acid and methanol are recycled, and a lower-layer catalyst is recycled. The yield of the p-tert-butyl methyl benzoate is 80 percent, and the purity is more than or equal to 99.99 percent.
Example 6
Adding raw materials of methanol and p-tert-butyl benzoic acid with a molar ratio of 5:1 into a reactor, adding a perfluorinated sulfonic acid resin catalyst with the raw material weight percentage of 10%, heating, stirring under the conditions of a reaction temperature of 140 ℃ and a reaction pressure of 2Mpa, and carrying out esterification reaction. After 4 hours of reaction, discharging reaction liquid, performing centrifugal separation, obtaining an upper-layer product, namely a crude product of p-tert-butyl benzoic acid methyl ester, water and a small amount of raw materials of p-tert-butyl benzoic acid and methanol, performing rotary evaporation on the upper-layer product to remove the methanol and the water firstly, and then performing rotary evaporation to obtain a target product of p-tert-butyl benzoic acid methyl ester, wherein unreacted p-tert-butyl benzoic acid and methanol are recycled, and a lower-layer catalyst is recycled. The yield of the p-tert-butyl methyl benzoate is 94 percent, and the purity is more than or equal to 99.99 percent.
Example 7
Mixing the components in a molar ratio of 20: 1, adding raw materials of methanol and p-tert-butyl benzoic acid into a reactor, adding a polystyrene sulfonic acid resin catalyst with the raw material weight percentage of 10%, heating, stirring under the conditions of the reaction temperature of 100 ℃ and the reaction pressure of 1.5Mpa, and carrying out esterification reaction. After 4 hours of reaction, discharging reaction liquid, performing centrifugal separation, obtaining an upper-layer product, namely a crude product of p-tert-butyl benzoic acid methyl ester, water and a small amount of raw materials of p-tert-butyl benzoic acid and methanol, performing rotary evaporation on the upper-layer product to remove the methanol and the water firstly, and then performing rotary evaporation to obtain a target product of p-tert-butyl benzoic acid methyl ester, wherein unreacted p-tert-butyl benzoic acid and methanol are recycled, and a lower-layer catalyst is recycled. The yield of the p-tert-butyl methyl benzoate is 96 percent, and the purity is more than or equal to 99.99 percent.
Example 8
Mixing the components in a molar ratio of 20: 1, adding raw materials of methanol and p-tert-butyl benzoic acid into a reactor, adding a polystyrene sulfonic acid resin catalyst with the raw material weight percentage of 10%, heating, stirring under the conditions of the reaction temperature of 120 ℃ and the reaction pressure of 1.6Mpa, and carrying out esterification reaction. After reacting for 2h, discharging reaction liquid, centrifugally separating to obtain an upper-layer product, namely a crude product of p-tert-butyl benzoic acid methyl ester, water and a small amount of raw materials of p-tert-butyl benzoic acid and methanol, carrying out rotary evaporation on the upper-layer product to remove the methanol and the water firstly, and then carrying out rotary evaporation to obtain a target product of p-tert-butyl benzoic acid methyl ester, wherein unreacted p-tert-butyl benzoic acid and methanol are recycled, and a lower-layer catalyst is recycled. The yield of the p-tert-butyl methyl benzoate is 95 percent, and the purity is more than or equal to 99.99 percent.
Example 9
Mixing the components in a molar ratio of 8: 1, adding raw materials of methanol and p-tert-butyl benzoic acid into a reactor, adding a polystyrene sulfonic acid resin catalyst with the raw material weight percentage of 10%, heating, stirring under the conditions of the reaction temperature of 120 ℃ and the reaction pressure of 1.4Mpa, and carrying out esterification reaction. After 5h of reaction, discharging reaction liquid, performing centrifugal separation, obtaining an upper-layer product, namely a crude product of p-tert-butyl benzoic acid methyl ester, water and a small amount of raw materials of p-tert-butyl benzoic acid and methanol, performing rotary evaporation on the upper-layer product to remove the methanol and the water firstly, and then performing rotary evaporation to obtain a target product of p-tert-butyl benzoic acid methyl ester, wherein unreacted p-tert-butyl benzoic acid and methanol are recycled, and a lower-layer catalyst is recycled. The yield of the p-tert-butyl methyl benzoate is 96 percent, and the purity is more than or equal to 99.99 percent.
Example 10
Mixing the components in a molar ratio of 8: 1, adding raw materials of methanol and p-tert-butyl benzoic acid into a reactor, adding a polystyrene sulfonic acid resin catalyst with the raw material weight percentage of 10%, heating, stirring under the conditions of the reaction temperature of 100 ℃ and the reaction pressure of 0.9Mpa, and carrying out esterification reaction. After 8h of reaction, discharging reaction liquid, performing centrifugal separation, obtaining an upper-layer product, namely a crude product of p-tert-butyl benzoic acid methyl ester, water and a small amount of raw materials of p-tert-butyl benzoic acid and methanol, performing rotary evaporation on the upper-layer product to remove the methanol and the water firstly, and then performing rotary evaporation to obtain a target product of p-tert-butyl benzoic acid methyl ester, wherein unreacted p-tert-butyl benzoic acid and methanol are recycled, and a lower-layer catalyst is recycled. The yield of the p-tert-butyl methyl benzoate is 95 percent, and the purity is more than or equal to 99.99 percent.
Although the invention has been described in detail hereinabove by way of general description, specific embodiments and experiments, it will be apparent to those skilled in the art that many modifications and improvements can be made thereto based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.