A continuous process for the production of methyl benzoate

Abstract

The present application relates to a kind of continuous production methods of methyl cinnamate.The method includes that trimethyl orthoacetate and iso-pentenol are condensed in the presence of catalyst in condensation column, reaction liquid containing condensation product is respectively taken from the condensation column bottom, and the step that methanol is taken from the condensation column top;And the reaction liquid is transported to rearrangement column and is carried out claisen rearrangement reaction in the presence of catalyst, the step that methyl cinnamate crude product is respectively taken from the rearrangement column bottom, and methanol is taken from the rearrangement column top.The method is carried out at normal pressure and lower temperature, higher safety, and reaction time is short, reaction rate is faster, while side reaction is obviously inhibited, and the yield of target product is further improved.

Description

Technical Field

[0001] This invention specifically relates to a continuous production method for methyl benzoate. Background Technology

[0002] Methyl benzoate, chemically known as methyl 3,3-dimethyl-4-pentenoate, is a colorless, transparent, flammable liquid. It is insoluble in water but readily soluble in organic solvents such as alcohols, ethers, and esters. Methyl benzoate is an important intermediate in the preparation of pyrethroids and can be used to synthesize methyl dichloroquine and trifluorochloroquine, as well as pyrethroid insecticides for sanitary and agricultural applications.

[0003] Currently, in industry, methyl benzoate is commonly produced by reacting trimethyl orthoacetate and isopentenol in the presence of a catalyst. This method involves a condensation reaction between trimethyl orthoacetate and isopentenol via a catalyst, followed by a Claisen rearrangement reaction. This produces methyl benzoate as a product, along with methanol as a byproduct. Purification is then achieved through methods such as distillation. Since this reaction is reversible, distillation is typically required during the reaction to remove the methanol byproduct and promote the forward reaction.

[0004] Chinese patent CN116082160A discloses a method for continuous production of methyl benzoate by reactive distillation, comprising the following steps: 1) Isopentenol is pumped to an isopentenol preheater and heated to 90-110°C before being fed into the lower part of a condensation tower; trimethyl orthoacetate is pumped to an orthoacetate preheater and heated to 90-110°C before being fed into the middle part of the condensation tower; propionic acid is pumped to the upper part of the condensation tower; 2) Isopentenol and trimethyl orthoacetate undergo a condensation reaction at a reaction pressure of 0.5-0.8 MPa to produce methyl benzoate and methanol; the condensation tower has two main functions: first, to serve as the site of the condensation reaction; and second, to distill and separate the generated methanol and excess trimethyl orthoacetate from the reaction system; 3) The crude methyl benzoate at the bottom of the condensation tower is directly fed to a product distillation tower for separation, and the finished methyl benzoate is obtained at the top of the tower. Although the continuous production method of this patent has a high yield, the reaction time is 18-24 hours. The long reaction time will lead to a decrease in reaction selectivity and the yield needs to be improved. In addition, the method is a high temperature and high pressure reaction, which has poor safety. Furthermore, the method uses propionic acid as a catalyst, which is a strong acid and has high requirements for equipment materials, resulting in increased production costs.

[0005] Chinese patent CN102557934A discloses a continuous synthesis method for methyl benzoate. This method uses isopentenol and trimethyl orthoacetate as raw materials and phenol as a reaction catalyst. The process steps include: (A) Batching: Trimethyl orthoacetate, isopentenol, and phenol catalyst are continuously added to a batching vessel and mixed uniformly; (B) Synthesis and Separation: The materials in the batching vessel are continuously sent to a synthesis separation tower for reaction, while the byproduct methanol and excess trimethyl orthoacetate are continuously separated from the top of the tower, and the bottom liquid is continuously collected from the bottom of the tower; (C) Vacuum Distillation: The bottom liquid of the synthesis separation tower is continuously injected into a distillation vessel for vacuum distillation to separate the finished product, methyl benzoate. This patent uses a homogeneous liquid catalyst, which presents difficulties in catalyst separation and recovery. Furthermore, phenol is volatile and has a high melting point, making it prone to precipitation during the reaction system and post-processing, potentially clogging pipelines. Furthermore, the reaction has already occurred during the mixing process, and the byproduct methanol is not separated during the mixing process, which will reduce the reaction selectivity and result in a low product yield.

[0006] Chinese patent CN102001940B discloses a method for synthesizing methyl benzoate, comprising the following steps: A) At 0-40℃, trimethyl orthoacetate, a catalyst, and isopentenol are continuously fed into a tubular or batch reactor at a molar ratio of 1:0.0005-0.02:0.1-0.5 and mixed for 5-60 minutes to generate a methyl benzoate synthesis feed solution; B) The methyl benzoate synthesis feed solution generated in step A) is continuously fed into a separation tower to remove byproduct methanol and excess trimethyl orthoacetate, and the bottom liquid is then distilled to obtain the methyl benzoate product. This method has a low yield of the target product. Summary of the Invention

[0007] The purpose of this invention is to provide a continuous production method for methyl benzoate. This method is carried out under normal pressure and at relatively low temperatures, ensuring high safety, with a short reaction time, a fast reaction rate, and significant suppression of side reactions, thereby further improving the yield of the target product.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] A continuous production method for methyl benzoate, the continuous production method comprising carrying out a condensation reaction of trimethyl orthoacetate and isopentenol in a condensation tower in the presence of a catalyst, and collecting the condensation products from the bottom of the condensation tower. The steps include: the reaction liquid, the extraction of methanol from the top of the condensation tower; and the transfer of the reaction liquid to a rearrangement tower for the Claisen rearrangement reaction in the presence of a catalyst, the extraction of crude methyl benzoate from the bottom of the rearrangement tower, and the extraction of methanol from the top of the rearrangement tower.

[0010] In this invention, both the aforementioned condensation tower and rearrangement tower are chemical process towers, and their structures adopt conventional chemical process tower structures, such as those similar to those of distillation towers. The structures of the aforementioned condensation tower and rearrangement tower are not explicitly limited; they are named only based on their intended use in condensation and rearrangement reactions, respectively.

[0011] In some embodiments, the temperature of the condensation reaction is 65–85°C.

[0012] In some embodiments, the Claisen rearrangement reaction is carried out at a temperature of 95–130°C.

[0013] In existing technologies, methyl pentaminate is commonly produced industrially from trimethyl orthoacetate and isopentenol via intermittent pressurized reaction and distillation. Although continuous synthesis methods exist, the Claisen rearrangement reaction requires high temperatures, which in turn necessitates high temperatures for continuous synthesis. Furthermore, current techniques require this reaction to be carried out under high pressure, yet the reaction rate remains low. This results in a long reaction time (longer material residence time) for the entire continuous synthesis method. The high reaction temperature and long material residence time lead to a significant increase in side reactions and a substantial increase in waste products (byproducts, impurities, etc.) in the reaction system.

[0014] The inventors of this application discovered through research that the condensation reaction of trimethyl orthoacetate and isopentenol, along with the Claisen rearrangement reaction, are carried out in two separate process towers. The first process tower is a condensation tower, where the condensation reaction of the two compounds takes place. Methanol, a byproduct, is collected from the top of this tower, while the condensation product, mainly composed of the two compounds, is collected from the bottom. The reaction solution containing the condensation product is then fed to a second process column, the rearrangement column, for the Claisen rearrangement reaction. Methanol byproduct is collected from the top of this rearrangement column, and crude methyl benzoate is collected from the bottom. This improves the selectivity of the reaction, significantly inhibits side reactions, and thus significantly increases the yield of the target product, methyl benzoate.

[0015] The condensation reaction is shown below, and the condensation reaction is carried out in a condensation tower:

[0016]

[0017] The obtained condensation product was fed into a rearrangement column to carry out the Claisen rearrangement reaction as shown in the following reaction formula, in which the nucleophilic elimination reaction is an intermediate reaction with a very short reaction time and the corresponding intermediate state is unstable. After the Claisen rearrangement reaction, the target product methyl benzoate was obtained.

[0018]

[0019] The condensation product may undergo the following side reaction with the starting material isopentenol to generate the byproduct isopentenyl pentinate:

[0020]

[0021] In this invention, the reaction liquid, whose main component is the aforementioned condensation product, is collected from the bottom of the condensation tower and conveyed to the rearrangement tower. At a lower condensation reaction temperature, contact with the feedstock isopentenol is minimized, thereby significantly reducing the occurrence of the aforementioned side reactions and improving reaction selectivity. In this invention, the condensation reaction of the two feedstocks is completed in the condensation tower, and methanol is separated from the top of the tower while the condensation product is separated from the bottom. This promotes the shift of the equilibrium of the condensation reaction (an equilibrium reversible reaction) towards the forward reaction direction, thereby increasing the yield of the condensation reaction. The condensation product is then conveyed to the rearrangement tower, where a higher reaction temperature than the condensation reaction is used for the rearrangement reaction. This allows the condensation product to undergo the Claisen rearrangement, generating the target product, methyl benzoate. This avoids the high temperature during the Claisen rearrangement reaction, which would lead to increased side reactions between the condensation product and the feedstock isopentenol, thus increasing the yield of the target product while shortening the reaction time and increasing the reaction rate.

[0022] In some embodiments, the condensation column is a vertical column, comprising an upper rectification section, a middle reaction section, and a lower stripping section; the rectification section has 5 to 12 trays, the reaction section has 8 to 30 trays, and the stripping section has 5 to 10 trays.

[0023] In some embodiments, the residence time of the reaction liquid on each tray in the reaction section of the condensation tower is 20 to 200 seconds.

[0024] In some embodiments, the temperature of the rectification section of the condensation tower is 30–60°C.

[0025] In some embodiments, the temperature of the reaction section of the condensation tower is 65–85°C.

[0026] In some embodiments, the temperature of the stripping section of the condensation tower is 90–110°C. The reaction temperature of the stripping section of the condensation tower should not be too high, as excessively high temperatures can easily cause the condensation product to distill upwards, leading to rearrangement reactions within the condensation tower, generating methanol, and hindering the suppression of side reactions.

[0027] In some embodiments, the catalyst for the condensation reaction is packed in the reaction section of the condensation tower at a loading rate of 0.1–0.7 m³. 3 catalyst / m 3 Reaction section.

[0028] In some embodiments, the condensation tower operates at atmospheric pressure. This invention can be carried out at atmospheric pressure, which significantly improves safety and reduces production costs compared to high-pressure reactions in the prior art.

[0029] In some embodiments, the reflux ratio of the condensation tower is 0.5 to 6.

[0030] In some embodiments, the continuous production method further includes the step of introducing trimethyl orthoacetate and isopentenol into the reaction section of the condensation tower.

[0031] In some implementations, the number of feed trays for trimethyl orthoacetate differs from that for isopentenol by more than two trays. Feeding trimethyl orthoacetate and isopentenol separately prevents direct contact between the two streams, avoiding localized excessive concentrations and direct reaction.

[0032] In some embodiments, the catalyst used for the condensation reaction is selected from acidic cation exchange resins or aluminum trichloride. The catalyst used in this invention is a heterogeneous catalyst, which facilitates subsequent recovery and recycling.

[0033] In some embodiments, the acidic cation exchange resin is selected from one or more combinations of Amberlyst-15, Amberlyst-35, and Amberlyst-46.

[0034] In some embodiments, the molar ratio of isopentenol to trimethyl orthoacetate is 1:1 to 5. That is, the trimethyl orthoacetate raw material is in stoichiometric amounts, and is usually in excess.

[0035] In some embodiments, the condensation product in the reaction solution The mass percentage is 55% to 65%. That is, in this invention, the degree of condensation reaction in the condensation tower is very high.

[0036] In some embodiments, the rearrangement column is a vertical column and includes an upper rectification section, a middle reaction section, and a lower stripping section; the rectification section has 5 to 20 trays, the reaction section has 8 to 30 trays, and the stripping section has 2 to 10 trays.

[0037] In some embodiments, the residence time of the reactants on each tray in the reaction section of the rearrangement tower is 20 to 300 seconds.

[0038] In some embodiments, the temperature of the rectification section of the rearrangement column is 70–90°C.

[0039] In some embodiments, the temperature of the reaction section of the rearrangement tower is 100–130°C.

[0040] In some embodiments, the temperature of the stripping section of the rearrangement tower is 140–160°C.

[0041] In some embodiments, the catalyst for the Claisen rearrangement reaction is packed in the reaction section of the rearrangement tower at a loading rate of 0.2–0.8 m³. 3 catalyst / m 3 Reaction section.

[0042] In some embodiments, the reaction solution is fed to the reaction section of a rearrangement tower.

[0043] In some embodiments, the rearrangement tower operates at atmospheric pressure. Both the condensation and rearrangement reactions of this invention are carried out at atmospheric pressure.

[0044] In some embodiments, the reflux ratio of the rearrangement tower is 0.5 to 4.

[0045] In some embodiments, the catalyst used for the Claisen rearrangement reaction is a solid acid catalyst, comprising a support and an inorganic acid supported on the support. The catalyst used in this invention is a heterogeneous catalyst, facilitating subsequent recovery and recycling. The supported solid acid catalyst can withstand higher temperatures in the rearrangement reaction.

[0046] In some embodiments, the carrier is selected from one or more combinations of molecular sieves, silica, quartz sand, and diatomaceous earth.

[0047] In some embodiments, the inorganic acid is selected from phosphoric acid or sulfuric acid.

[0048] In some embodiments, the loading of the inorganic acid is 1.0%-6.0% based on the mass of the carrier.

[0049] In some embodiments, the continuous production method further includes the step of collecting trimethyl orthoacetate from the top of the rearrangement column. The trimethyl orthoacetate feedstock is typically used in excess, and the unreacted excess trimethyl orthoacetate can be collected from the top of the rearrangement column.

[0050] In some embodiments, the continuous production method includes the step of collecting a mixture of methanol and trimethyl orthoacetate from the top of the rearrangement tower.

[0051] Furthermore, the continuous production method further includes the step of passing the mixture of methanol and trimethyl orthoacetate into a distillation column for separation.

[0052] In some embodiments, the crude methyl benzoate contains methyl benzoate at a mass percentage of 91.0% or more. The reaction selectivity of this invention is significantly improved, and the content of the target product in the crude product is significantly increased.

[0053] In some embodiments, the continuous production method further includes the step of conveying the crude methyl benzoate to a distillation column for purification to obtain methyl benzoate.

[0054] In some embodiments, the purification is performed by vacuum distillation.

[0055] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0056] This invention involves conducting the condensation reaction of trimethyl orthoacetate and isopentenol, along with the Claisen rearrangement reaction, in two separate process towers. The first process tower is a condensation tower, where the condensation reaction of the two compounds takes place. Methanol, a byproduct, is collected from the top of this tower, while the condensation product, mainly composed of the two compounds, is collected from the bottom. The reaction solution containing the condensation product is then fed to a second process column, the rearrangement column, for the Claisen rearrangement reaction. Methanol byproduct is collected from the top of this rearrangement column, and crude methyl benzoate is collected from the bottom. This improves the selectivity of the reaction, significantly inhibits side reactions, and thus significantly increases the yield of the target product, methyl benzoate.

[0057] In this invention, the reaction liquid, whose main component is the aforementioned condensation product, is collected from the bottom of the condensation tower and transported to the rearrangement tower. This achieves the goal of minimizing contact between the product and the raw material isopentenol at a lower condensation reaction temperature, thereby significantly reducing the occurrence of side reactions in the condensation reaction between the condensation product and the raw material isopentenol and improving the selectivity of the reaction.

[0058] The crude methyl benzoate of the present invention contains more than 91.0% methyl benzoate by mass. After purification by vacuum distillation, the yield of the target product methyl benzoate can be more than 89.8%.

[0059] The continuous synthesis method of the present invention is carried out under normal pressure and at relatively low temperature, which is safe, has a short reaction time, a fast reaction rate, and significantly suppresses side reactions, thereby further improving the yield of the target product.

[0060] This invention uses a heterogeneous catalyst, which facilitates catalyst recovery and post-processing, further reducing production costs. Attached Figure Description

[0061] Figure 1 This is a schematic diagram of the apparatus flow for a continuous production method of methyl benzoate in an embodiment of the present invention.

[0062] Figure 2 This is the mass spectrum of the condensation product in Example 1 of the present invention;

[0063] Among them, 1-condensation tower; 2-rectification section of condensation tower; 3-reaction section of condensation tower; 4-stripping section of condensation tower; 5-methanol receiver; 6-rearrangement tower; 7-rectification section of rearrangement tower; 8-reaction section of rearrangement tower; 9-stripping section of rearrangement tower; 10-methanol and trimethyl orthoacetate distillation tower; 11-methyl benzoate distillation tower. Detailed Implementation

[0064] The technical solutions of the present invention will be described in detail below with reference to specific embodiments, so that those skilled in the art can better understand and implement the technical solutions of the present invention, but the present invention is not limited to the scope of the examples described.

[0065] In this invention, "tower top" and "tower bottom" are defined from the perspective of an observer facing the device system, such as... Figure 1 As shown, the top is above the paper surface, and the bottom is below the paper surface.

[0066] Example 1

[0067] This embodiment provides a continuous production method for methyl benzoate, the specific steps of which are as follows:

[0068] like Figure 1 As shown, at room temperature, trimethyl orthoacetate was continuously pumped into the reaction section 3 of condensation column 1 at a flow rate of 120 kg / h, and isopentenol at a flow rate of 43 kg / h. Condensation column 1 consists of a rectification section 2, a reaction section 3, and a stripping section 4, arranged sequentially from top to bottom. The total theoretical number of trays in condensation column 1 is 24, with 9 trays in rectification section 2, 5 in reaction section 3, and 10 in stripping section 4. The inlet for trimethyl orthoacetate is located at the 10th tray from the top, and the inlet for isopentenol is located at the 12th tray from the top. The catalyst used for the condensation reaction was acidic cation exchange resin Amberlyst-15, which was packed into the reaction section 3 of condensation column 1 at a catalyst loading rate of 0.4 m³. 3 catalyst / m 3 Reaction Section 3. The two raw materials undergo a condensation reaction on the catalyst bed. The temperature at the top of the condensation tower 1 is controlled at 50°C, the temperature in reaction section 3 is 80°C, the temperature at the bottom of the tower is about 100°C, and the reflux ratio is 3. The by-product methanol is continuously collected from the top of the tower and transported to the methanol receiver 5 through pipeline.

[0069] The main component collected from the bottom of condensation tower 1 is condensation product. The reaction solution (in which the mass percentage of the condensation product is 59.80%, and the mass spectrum of the condensation product is shown in Figure 1) Figure 2 As shown, m / z 41 is m / z 43.1 is m / z 69.1 is m / z 85 is m / z 89.1 is m / z 100.1 is The molecular ion peak of the condensation product (173) is continuously pumped into rearrangement column 6. Rearrangement column 6, from top to bottom, consists of a rectification section 7, a reaction section 8, and a stripping section 9. The total theoretical number of trays in rearrangement column 6 is 20, with 8 trays in rectification section 7, 8 in reaction section 8, and 4 in stripping section 9. The feed inlet for the reaction liquid is located at the 9th tray from the top of rearrangement column 6. A solid acid catalyst is used for the rearrangement reaction, with silica as the support and phosphoric acid as the inorganic acid. Based on the mass of the support, the phosphoric acid loading is 1.0%. It is packed into reaction section 8 of rearrangement column 6 at a catalyst loading of 0.6 m³. 3 catalyst / m 3 In reaction section 8, the aforementioned condensation products undergo a Claisen rearrangement reaction on a catalyst bed. The top temperature of rearrangement column 6 is controlled at 70°C, the temperature of reaction section 8 at 120°C, the bottom temperature at 140°C, and the reflux ratio at 3. An excess mixture of trimethyl orthoacetate and methanol byproducts is continuously collected from the top of rearrangement column 6 and piped to methanol and trimethyl orthoacetate distillation column 10 for distillation separation to obtain methanol as a byproduct. The separated trimethyl orthoacetate can be returned to condensation column 1 for condensation reaction. Crude methyl benzoate is continuously collected from the bottom of rearrangement column 6. The mass content of methyl benzoate in the crude methyl benzoate is determined by gas chromatography, and the results are shown in Table 1 below.

[0070] The crude methyl benzoate was transported via pipeline to the methyl benzoate distillation column 11 for vacuum distillation purification, and the target product methyl benzoate was finally obtained. The purity and total reaction yield are shown in Table 1 below.

[0071] Examples 2-9

[0072] Examples 2-9 provide a continuous production method for methyl benzoate, with the specific steps basically the same as in Example 1, except for the adjustment of the types of catalysts for the condensation reaction and the rearrangement reaction (both with an acid loading of 1.0%), the temperatures of the condensation tower (including the rectification section, reaction section, and stripping section), the temperatures of the rearrangement tower (including the rectification section, reaction section, and stripping section), and the reflux ratios of the condensation tower and the rearrangement tower, as shown in Table 1 below. The mass content of the condensation product, the mass content of methyl benzoate in the crude product, the purity of methyl benzoate after distillation, and the overall yield are shown in Table 1 below.

[0073] Comparative Example 1

[0074] Comparative Example 1 provides a continuous production method for methyl benzoate, with the specific steps being basically the same as in Example 1, except that the temperature of the stripping section of the condensation tower is adjusted, as shown in Table 1 below. The mass content of the condensation product, the mass content of methyl benzoate in the crude product, the purity of methyl benzoate after distillation, and the total yield are shown in Table 1 below.

[0075] Comparative Example 2

[0076] Comparative Example 2 provides a continuous production method for methyl benzoate, which uses only one process tower for condensation and rearrangement. The specific steps are as follows:

[0077] At room temperature, trimethyl orthoacetate was continuously pumped into the reaction section (including condensation and rearrangement) of the process column at a flow rate of 120 kg / h, and isopentenol at a flow rate of 43 kg / h. The process column, from top to bottom, consists of a rectification section, a reaction section, and a stripping section. The total theoretical number of plates in the process column is 24, with 9 in the rectification section, 5 in the reaction section, and 10 in the stripping section. The inlet for trimethyl orthoacetate is located on the 10th plate from the top, and the inlet for isopentenol is located on the 12th plate from the top. A solid acid catalyst was used for the reaction, with silica as the support and phosphoric acid as the inorganic acid. Based on the mass of the support, the phosphoric acid loading was 1.0%, and it was packed into the reaction section of the process column at a catalyst loading of 0.6 m³. 3 catalyst / m 3 Reaction Section. The two raw materials undergo condensation and rearrangement reactions on a catalyst bed. The temperature at the top of the process column is controlled at 105℃, the temperature in the reaction section at 125℃, and the temperature at the bottom of the column at approximately 140℃. The reflux ratio is 3. Methanol, a byproduct, is continuously collected from the top of the column, and crude methyl benzoate is continuously collected from the bottom. The mass content of methyl benzoate in the crude methyl benzoate is determined by gas chromatography, and the result is 87.5% by mass.

[0078] The crude methyl benzoate was transported via pipeline to a methyl benzoate distillation column for vacuum distillation purification, finally yielding the target product methyl benzoate with a purity of 99.8% and an overall reaction yield of 80.6%.

[0079]

[0080] As can be seen, this invention improves reaction selectivity and significantly suppresses side reactions by carrying out the condensation reaction of trimethyl orthoacetate and isopentenol and the Claisen rearrangement reaction separately in a condensation tower and a rearrangement tower, respectively. Methanol, a byproduct, is collected from the top of both towers, while the condensation product is collected from the bottom of the condensation tower and sent to the rearrangement tower for the rearrangement reaction. This significantly increases the yield of the target product, methyl benzoate. Simultaneously, controlling the temperature of the condensation tower bottom to prevent excessively high temperatures ensures that the condensation product undergoes minimal rearrangement reaction within the condensation tower, further improving reaction selectivity and the yield of the target product.

[0081] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A continuous production method for methyl benzoate, characterized in that: The continuous production method includes carrying out a condensation reaction of trimethyl orthoacetate and isopentenol in a condensation tower in the presence of a catalyst, and collecting the condensation products from the bottom of the condensation tower. The steps include: the reaction liquid, the step of collecting methanol from the top of the condensation tower; and the step of feeding the reaction liquid into the rearrangement tower to carry out the Claisen rearrangement reaction in the presence of a catalyst, collecting crude methyl benzoate from the bottom of the rearrangement tower and collecting methanol from the top of the rearrangement tower. The condensation tower is a vertical tower, and includes an upper rectification section, a middle reaction section and a lower stripping section. The temperature of the stripping section of the condensation tower is 90~110℃; The catalyst used for the condensation reaction is selected from acidic cation exchange resin or aluminum trichloride; The catalyst used for the Claisen rearrangement reaction is a solid acid catalyst, comprising a support and an inorganic acid supported on the support; The condensation reaction is carried out at a temperature of 65-85°C; the Claisen rearrangement reaction is carried out at a temperature of 95-130°C.

2. The continuous production method of methyl benzoate according to claim 1, characterized in that: The rectification section has 5 to 12 trays, the reaction section has 5 to 30 trays, and the stripping section has 5 to 10 trays.

3. The continuous production method of methyl benzoate according to claim 2, characterized in that: The residence time of the reaction liquid on each tray in the reaction section of the condensation tower is 20 to 200 seconds; and / or, the temperature of the rectification section of the condensation tower is 30 to 60°C.

4. The continuous production method of methyl benzoate according to claim 2, characterized in that: The temperature of the reaction section of the condensation tower is 65~85℃.

5. The continuous production method of methyl benzoate according to claim 2, characterized in that: The catalyst used for the condensation reaction is packed in the reaction section of the condensation tower at a loading rate of 0.1–0.7 m³. 3 catalyst / m 3 The reaction section; and / or, the operating pressure of the condensation tower is atmospheric pressure; and / or, the reflux ratio of the condensation tower is 0.5~6.

6. The continuous production method of methyl benzoate according to claim 2, characterized in that: The continuous production method further includes the step of introducing trimethyl orthoacetate and isopentenol into the reaction section of the condensation tower.

7. The continuous production method of methyl benzoate according to claim 6, characterized in that: The number of feed trays for trimethyl orthoacetate differs from that for isopentenol by more than two trays.

8. The continuous production method of methyl benzoate according to claim 1, characterized in that: The acidic cation exchange resin is selected from one or more combinations of Amberlyst-15, Amberlyst-35 and Amberlyst-46; and / or, the molar ratio of isopentenol to trimethyl orthoacetate is 1:1 to 5.

9. The continuous production method of methyl benzoate according to claim 1, characterized in that: The condensation product in the reaction solution The mass percentage is 55%~65%.

10. The continuous production method of methyl benzoate according to claim 1, characterized in that: The rearrangement column is a vertical column, and includes an upper rectification section, a middle reaction section and a lower stripping section; the rectification section has 5 to 20 trays, the reaction section has 8 to 30 trays and the stripping section has 2 to 10 trays.

11. The continuous production method of methyl benzoate according to claim 10, characterized in that: The residence time of the reactants on each tray in the reaction section of the rearrangement column is 20 to 300 seconds; and / or, the temperature of the rectification section of the rearrangement column is 70 to 90°C; and / or, the temperature of the reaction section of the rearrangement column is 100 to 130°C; and / or, the temperature of the stripping section of the rearrangement column is 140 to 160°C.

12. The continuous production method of methyl benzoate according to claim 10, characterized in that: The catalyst used in the Claisen rearrangement reaction is packed in the reaction section of the rearrangement tower at a loading rate of 0.2–0.8 m³. 3 catalyst / m 3 The reaction section; and / or, the reaction solution is conveyed to the reaction section of the rearrangement tower; and / or, the operating pressure of the rearrangement tower is atmospheric pressure; and / or, the reflux ratio of the rearrangement tower is 0.5 to 4.

13. The continuous production method of methyl benzoate according to claim 1, characterized in that: The carrier is selected from one or more combinations of molecular sieves, silica, quartz sand and diatomaceous earth; and / or, the inorganic acid is selected from phosphoric acid or sulfuric acid.

14. The continuous production method of methyl benzoate according to claim 1, characterized in that: The continuous production method further includes the step of collecting trimethyl orthoacetate from the top of the rearrangement tower.

15. The continuous production method of methyl benzoate according to claim 1, characterized in that: The crude methyl benzoate contains methyl benzoate at a mass percentage of 91.0% or more; and / or, the continuous production method further includes the step of conveying the crude methyl benzoate to a distillation column for purification to obtain methyl benzoate.

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