System and method for continuous preparation of cyclohexyl acetate

Abstract

The present invention provides a system and method for continuously preparing cyclohexyl acetate. The system for continuously preparing cyclohexyl acetate provided by the present application comprises a reaction unit, the reaction unit comprises a reactor, the reactor comprises a cylinder, and the interior of the cylinder is sequentially provided with a first mixing section, a first reaction section, a first separation section, a second mixing section, a second reaction section, and a second separation section from bottom to top; wherein, the first reaction section and the second reaction section are both filled with catalysts, and the first separation section and the second separation section are both provided with separation fillers. The system for continuously preparing cyclohexyl acetate provided by the present application can not only realize the continuous reaction of acetic acid and cyclohexene, but also conform to the reaction kinetics, increase the reaction rate, reduce the circulation time of cyclohexene in the reactor, and remove the generated cyclohexyl acetate reaction liquid in sections, so as to achieve a cyclohexene conversion rate of ≥99%, and at the same time, it can also reduce the generation of by-products and improve selectivity.

Description

Technical Field

[0001] The invention relates to the technical field of cyclohexyl acetate preparation, and in particular to a system and method for continuously preparing cyclohexyl acetate. Background Art

[0002] Cyclohexyl acetate is mainly used in the food and beverage industries to prepare fruity flavors such as apples, bananas, currants and raspberries. Cyclohexanol and acetic acid are commonly used as raw materials in industry, and concentrated sulfuric acid is used as a catalyst to synthesize cyclohexyl acetate. However, concentrated sulfuric acid has strong acidity and strong oxidizing properties, and will cause serious corrosion to equipment. At the same time, the post-treatment process of acid waste liquid and catalyst regeneration is relatively complicated, which is a non-ideal and non-green process route. At present, the industry uses solid superacids and Lewis acids as catalysts, which can to a certain extent solve the characteristics of traditional catalysts such as environmental protection, complex post-treatment and difficulty in catalyst regeneration. However, this type of catalyst still has relatively low activity, the reaction is easy to reverse, resulting in low reactant conversion rate, and unstable process flow. Most importantly, the selectivity of cyclohexyl acetate in most of the reported literature is low, the atom economy is low, and there are many by-products, which limits the industrialization and scale of cyclohexyl acetate.

[0003] CN 110105208 A discloses a method for preparing cyclohexyl acetate. First, a modified resin catalyst is loaded into a reactor, and then the raw material cyclohexene and pure glacial acetic acid are mixed and pumped into the reactor, the reaction temperature is controlled to be 60-120°C, the reaction pressure is 0-1.0Mpa, and the obtained reaction solution is subjected to post-treatment to obtain cyclohexyl acetate. The method provided by the invention is simple to operate, suitable for large-scale industrial production, and has a high product yield. The catalyst used in the reaction process can be reused after post-treatment, which saves costs. However, the process uses a single reactor because acetic acid cannot be completely converted, and cyclohexyl acetate is mixed in the reaction solution, which reduces the concentration of cyclohexene and acetic acid in the reaction solution and reduces the conversion rate. In addition, subsequent separation will require a large amount of equipment investment and energy consumption.

[0004] CN 107434767 B discloses a method for preparing cyclohexanol and cyclohexyl acetate by using cyclohexene and acetic acid. The synthesis method comprises reacting cyclohexene and acetic acid under the action of a catalyst to obtain a crude cyclohexyl acetate product containing acetic acid; hydrolyzing water and the crude cyclohexyl acetate product containing acetic acid under the action of the catalyst, separating a mixture of cyclohexyl acetate and cyclohexanol from the mixture obtained by the reaction, and then rectifying the mixture of cyclohexyl acetate and cyclohexanol to obtain cyclohexyl acetate and cyclohexanol products respectively. The method provided by the invention has a simple process flow, but the product separation cost is relatively high.

[0005] CN 103664529 B discloses a method for co-producing cyclohexanol and ethanol. The method first uses reactive distillation to carry out an addition esterification reaction of acetic acid and cyclohexene to prepare cyclohexyl acetate; and then co-produces cyclohexanol and ethanol by hydrogenating cyclohexyl acetate. The method of the invention can prepare cyclohexanol and co-produce ethanol with high efficiency and low cost, and the cyclohexene conversion rate can reach 99%. However, the unreacted cyclohexene remaining in the reactive distillation is easy to cause flooding after enrichment in the tower, which is not conducive to the stability of operation, and as the operation time increases, the enriched cyclohexene is continuously circulated in the tower, and more by-products are generated at the high temperature of the reactive distillation tower, resulting in reduced selectivity.

[0006] Therefore, it is necessary to develop a system device and method that can efficiently react to produce cyclohexyl acetate with few by-products and high selectivity. Summary of the invention

[0007] The main purpose of the present invention is to provide a system and method for continuously preparing cyclohexyl acetate, so as to solve at least one of the problems of unstable operation, low reaction efficiency, low selectivity or high by-product content in the system for preparing cyclohexyl acetate in the prior art.

[0008] To achieve the above-mentioned object, according to one aspect of the present invention, a system for continuously preparing cyclohexyl acetate is provided, the system comprising a reaction unit, the reaction unit comprising a reactor, the reactor comprising a cylinder, the interior of the cylinder being provided with a first mixing section, a first reaction section, a first separation section, a second mixing section, a second reaction section, and a second separation section in sequence from bottom to top; wherein the first reaction section and the second reaction section are both filled with a catalyst, and the first separation section and the second separation section are both provided with a separation filler.

[0009] Furthermore, a first fluid distributor is provided between the first mixing section and the first reaction section, and a second fluid distributor is provided between the second mixing section and the second reaction section.

[0010] Furthermore, a first waste liquid discharge port is provided at the top of the first reaction section, and a second waste liquid discharge port is provided at the top of the second reaction section; and both the first reaction section and the second reaction section are provided with a temperature controller and a pressure sensor.

[0011] Furthermore, a first discharge port is provided at the bottom of the first separation section, and a second discharge port is provided at the bottom of the second separation section.

[0012] Furthermore, the first mixing section is provided with a first feed port, a third waste liquid discharge port is provided at the bottom of the first mixing section, and a cyclohexene discharge port is provided at the second mixing section.

[0013] Furthermore, the reaction unit also includes a gas-liquid separator having a first inlet and a second inlet, the first inlet is connected to the first separation section, the second inlet is connected to the second separation section, and the gas phase outlet of the gas-liquid separator is connected to the second mixing section.

[0014] Furthermore, the system also includes a raw material supply unit, which includes an acetic acid storage tank, a cyclohexene storage tank and a raw material mixing kettle. The acetic acid storage tank and the cyclohexene storage tank are respectively connected to the raw material mixing kettle, which is connected to the first mixing section. The raw material mixing kettle is used to mix acetic acid and cyclohexene and then transport them to the first mixing section. The cyclohexene storage tank is also connected to the second mixing section.

[0015] Furthermore, the raw material supply unit also includes a heater, which is arranged on the pipeline between the raw material mixing kettle and the first mixing section.

[0016] Furthermore, the system also includes a product collection unit, which includes a cyclohexyl acetate product temporary storage tank, the cyclohexyl acetate product temporary storage tank is connected to the liquid phase outlet of the gas-liquid separator, and a first acetic acid removal device is also arranged on the pipeline between the cyclohexyl acetate product temporary storage tank and the gas-liquid separator; the cyclohexyl acetate product temporary storage tank is also connected to the top of the reactor, and a condenser is also arranged on the pipeline between the cyclohexyl acetate product temporary storage tank and the reactor.

[0017] Furthermore, the product collection unit also includes a second acetic acid removal device, and the second acetic acid removal device is connected to the cyclohexyl acetate product temporary storage tank.

[0018] According to another aspect of the present invention, a method for continuously preparing cyclohexyl acetate is provided. The method is carried out using any one of the systems provided in the first aspect. The method comprises: mixing cyclohexene and acetic acid and passing them into a reactor, sequentially passing through a first mixing section, a first reaction section, a first separation section, a second mixing section, a second reaction section, and a second separation section, and collecting cyclohexyl acetate reaction liquid from the first separation section and the second separation section, respectively.

[0019] Furthermore, the above method also includes purifying the cyclohexyl acetate reaction liquid, and preferably the purification includes performing gas-liquid separation on the cyclohexyl acetate reaction liquid to obtain a vapor phase reactant and a liquid phase reaction liquid.

[0020] Furthermore, the purification also includes removing acetic acid from the liquid phase reaction liquid to obtain a cyclohexyl acetate product.

[0021] Furthermore, acetic acid and cyclohexene are first mixed into a feed reaction liquid and then introduced into the reactor. In the feed reaction liquid, the mass content of acetic acid is 20-95%, and the mass content of cyclohexene is 5-80%; preferably, the mass ratio of acetic acid to cyclohexene is 5:0.5-5.

[0022] Furthermore, the temperature of the feed reaction liquid is 30-80°C.

[0023] Furthermore, the residence time of the feed reaction liquid in the first reaction section is 5 to 60 minutes.

[0024] Furthermore, the reaction temperatures of the first reaction stage and the second reaction stage are both 60-100° C., and the pressures are both 0.1-5 MPa.

[0025] Furthermore, the temperature of the first separation section and the second separation section are both 80-140°C.

[0026] By applying the technical solution of the present application, the system for continuously preparing cyclohexyl acetate provided by the present application allows cyclohexene and acetic acid to be mixed and introduced into a reactor, and the mixture flows through a first mixing section, a first reaction section, a first separation section, a second mixing section, a second reaction section, and a second separation section in sequence, and cyclohexyl acetate reaction liquid is collected from the first separation section and the second separation section, respectively, so that cyclohexyl acetate is converted and separated more thoroughly, the equipment investment and energy consumption of subsequent separation are reduced, and the conversion rate is increased.

[0027] In addition, the system for continuously preparing cyclohexyl acetate provided in the present application can realize the continuous reaction of acetic acid and cyclohexene through the first mixing section, the first reaction section, the first separation section, the second mixing section, the second reaction section and the second separation section, which is more in line with the reaction kinetics, increases the reaction rate, reduces the circulation time of cyclohexene in the reactor, and removes the generated cyclohexyl acetate reaction liquid in stages, achieving a cyclohexene conversion rate of ≥99%, and can also reduce the generation of by-products and improve selectivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0029] Figure 1 A schematic diagram of the process of a system for continuously preparing cyclohexyl acetate according to Example 1 of the present invention is shown; and

[0030] Figure 2 The schematic diagram shows the structure of the reactor and the gas-liquid separator provided in the present embodiment 1 connected to form an assembly.

[0031] The above drawings include the following reference numerals:

[0032] 11. Cyclohexene storage tank; 12. Acetic acid storage tank; 13. Raw material mixing kettle; 14. Heater; 15. Circulating water storage tank; 100. Reactor; 110. First mixing section; 111. First feed inlet; 120. First reaction section; 121. First fluid distributor; 122. Third fluid distributor; 123. First waste liquid discharge outlet; 130. First separation section; 131. First reaction liquid discharge outlet; 132. First discharge outlet; 140. Second mixing section; 141. Second feed inlet; 142. Cyclohexene discharge outlet; 150. Second reaction section; 151. Second fluid distributor; 152. Fourth fluid distributor; 153. First waste liquid discharge outlet; 154. First separation section; 155. First reaction liquid discharge outlet; 156. First separation section; 157. First reaction liquid discharge outlet; 158. First separation section; 159. Second reaction liquid discharge outlet; 160. Second separation section; 161. Second reaction liquid discharge outlet; 162. First separation section; 163. First reaction liquid discharge outlet; 164. First separation section; 165. Second reaction liquid discharge outlet; 166. First separation section; 167. Second reaction liquid discharge outlet; 168. First separation section; 169. Second reaction liquid discharge outlet; 170. Second reaction liquid discharge outlet; 171. Second reaction liquid discharge outlet; 172. First separation section; 173. First reaction liquid discharge outlet; 174. First separation section; 175. Second reaction liquid discharge outlet; 176. body distributor; 153, second waste liquid discharge port; 160, second separation section; 161, second reaction liquid discharge port; 162, second discharge port; 170, lower head; 171, third waste liquid discharge port; 180, upper head; 181, first vent valve port; 182, vapor phase reactant discharge port; 190, first vent valve; 20, gas-liquid separator; 21, second vent valve; 30, cyclohexyl acetate product temporary storage tank; 31, first acetic acid removal device; 32, first acetic acid reaction liquid storage tank; 33, condenser; 34, second acetic acid removal device; 35, third vent valve; 36, second acetic acid reaction liquid storage tank. DETAILED DESCRIPTION

[0033] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0034] As analyzed in the background technology of this application, the existing method for preparing cyclohexyl acetate has at least one problem of low conversion rate, low selectivity or high by-product content. In order to solve this problem, this application provides a system and method for continuously preparing cyclohexyl acetate.

[0035] In a typical embodiment of the present application, a system for continuously preparing cyclohexyl acetate is provided, such as Figure 1 and Figure 2 As shown, the system includes a reaction unit, which includes a reactor 100. The reactor 100 includes a cylinder, and the interior of the cylinder is provided with a first mixing section 110, a first reaction section 120, a first separation section 130, a second mixing section 140, a second reaction section 150 and a second separation section 160 from bottom to top; wherein the first reaction section 120 and the second reaction section 150 are both filled with catalysts, and the first separation section 130 and the second separation section 160 are both provided with separation fillers.

[0036] By applying the technical solution of the present application, the system for continuously preparing cyclohexyl acetate provided by the present application allows cyclohexene and acetic acid to be mixed and introduced into a reactor 100, and the mixture flows through a first mixing section 110, a first reaction section 120, a first separation section 130, a second mixing section 140, a second reaction section 150, and a second separation section 160 in sequence, and cyclohexyl acetate reaction liquid is collected from the first separation section 130 and the second separation section 160, respectively, so that cyclohexyl acetate is converted and separated more thoroughly, the equipment investment and energy consumption of subsequent separation are reduced, and the conversion rate is increased.

[0037] In addition, the system for continuously preparing cyclohexyl acetate provided in the present application can realize the continuous reaction of acetic acid and cyclohexene through the first mixing section 110, the first reaction section 120, the first separation section 130, the second mixing section 140, the second reaction section 150 and the second separation section 160, which is more in line with the reaction kinetics, increases the reaction rate, reduces the circulation time of cyclohexene in the reactor 100, and removes the generated cyclohexyl acetate reaction liquid in stages, achieving a cyclohexene conversion rate of ≥99%, and at the same time can also reduce the generation of by-products and improve selectivity.

[0038] The reactor 100 provided in the present application is provided with a first separation section 130 and a second separation section 160. The first separation section 130 performs preliminary separation and concentration, removes the product, increases the conversion rate by promoting the reaction equilibrium to move to the right, and re-enters the vapor phase reactant into the second reaction section, thereby reducing the residence time of the unreacted reactant at the catalyst and reaction temperature, and reducing the generation of by-products. After the multi-stage feed is mixed and reacted, the second separation section 160 separates the product and the raw material reaction liquid, and the discharge is directly recycled.

[0039] In order to promote more uniform dispersion of the acetic acid and cyclohexene mixture transported from the first mixing section 110 to the first reaction section 120 and to make the materials more stable, it is preferred that a first fluid distributor 121 is provided between the first mixing section 110 and the first reaction section 120. For the same reason, a second fluid distributor 151 is also provided between the second mixing section 140 and the second reaction section 150.

[0040] The first fluid distributor 121 and the second fluid distributor 151 are not limited, and any components known to those skilled in the art for fluid distribution may be used, such as a liquid distributor, and there is no special limitation on the form and model of the liquid distributor.

[0041] It is preferred that the first fluid distributor 121 is disposed at the lower portion of the first reaction section 120 , which is more conducive to improving the distribution effect of the fluid distribution component and improving the reaction conversion rate. For the same reason, it is preferred that the second fluid distributor 151 is disposed at the lower portion of the second reaction section 150 .

[0042] Preferably, both the first separation section 130 and the second separation section 160 include a cylinder wall liquid collecting structure, and a first reaction liquid discharge port 131 is provided at the top of the first separation section 130 , and a second reaction liquid discharge port 161 is provided at the top of the second separation section 160 .

[0043] Based on the same reasons as above, it is preferred that a third fluid distributor 122 is provided between the first reaction section 120 and the first separation section 130, and a fourth fluid distributor 152 is provided between the second reaction section 150 and the second separation section 160. It is preferred that the third fluid distributor 122 is provided at the upper portion of the first reaction section 120, and the fourth fluid distributor 152 is provided at the upper portion of the second reaction section 150.

[0044] In order to facilitate the discharge of waste liquid, preferably, a first waste liquid discharge port 123 is provided at the top of the first reaction section 120, and a second waste liquid discharge port 153 is provided at the top of the second reaction section 150, for discharging the waste liquid and improving the selectivity of cyclohexyl acetate. Preferably, a temperature controller and a pressure sensor are provided in both the first reaction section 120 and the second reaction section 150 to facilitate controlling the temperature and pressure inside the first reaction section 120 and / or the second reaction section 150, improve the reaction efficiency, and reduce the residence time of the raw material liquid to be reacted.

[0045] In order to facilitate the loading of the catalyst, it is preferred that both the first reaction section 120 and the second reaction section 150 are provided with load-bearing partitions through which the liquid phase can flow.

[0046] In order to facilitate timely discharge of the generated reaction liquid, preferably, a first discharge port 132 is provided at the bottom of the first separation section 130 , and a second discharge port 162 is provided at the bottom of the second separation section 160 .

[0047] In order to facilitate the introduction of cyclohexene and acetic acid into the reactor 100, the first mixing section 110 is preferably provided with a first feed port 111 to facilitate the introduction of the mixture of cyclohexene and acetic acid into the reactor 100. The bottom of the first mixing section 110 of the reactor 100 is also provided with a third waste liquid discharge port 171 to facilitate the discharge of waste liquid from the first mixing section 110. In order to further reduce the generation of by-products, the second mixing section 140 is preferably provided with a cyclohexene discharge port 142, which is used to transport unreacted cyclohexene to the cyclohexene storage tank 11 for recycling.

[0048] Preferably, the above-mentioned reaction cylinder includes an upper head 180 and a lower head 170, the upper head 180 is arranged at the top of the second reaction section 150, and the upper head 180 is provided with a first vent valve port 181 and a vapor phase reactant discharge port 182, and the third waste liquid discharge port 171 is arranged on the lower head 170; wherein, the first vent valve port 181 is connected to the first vent valve 190.

[0049] In order to further improve the selectivity of cyclohexyl acetate, the reaction unit preferably also includes a gas-liquid separator 20, which has a first inlet and a second inlet, the first inlet is connected to the first reaction liquid discharge outlet 131 of the first separation section 130, the second inlet is connected to the second reaction liquid discharge outlet 161 of the second separation section 160, and the gas phase outlet of the gas-liquid separator 20 is connected to the second mixing section 140. The gas-liquid separator 20 is used to separate the vapor-phase reactants entrained in the cyclohexyl acetate reaction liquid separated by the first separation section 130 and the second separation section 160, and then return the vapor-phase reactants to the second mixing section 140 and continue to enter the second reaction section 150 for reaction.

[0050] The second mixing section 140 in the reactor 100 is further provided with a second feed port 141 , which is connected to the gas phase outlet of the gas-liquid separator 20 and is used to return the gas phase reactants separated by the gas-liquid separator 20 to the second mixing section 140 .

[0051] By providing the gas-liquid separator 20, the cyclohexyl acetate reaction liquid in the reactor 100 can be removed in time, and the internal circulation of the feed reaction liquid in the reactor 100 and the increase of by-products can be reduced. At the same time, the production fluctuations caused by the start-up and shutdown and abnormal process conditions can be reduced or eliminated, thereby ensuring the safety of the subsequent process.

[0052] Preferably, a second vent valve 21 is provided at the top of the gas-liquid separator 20 to further improve the safety of the gas-liquid separator 20 .

[0053] In order to further improve the stability of raw material supply in the above-mentioned system for continuously preparing cyclohexyl acetate, it is preferred that the system for continuously preparing cyclohexyl acetate further includes a raw material supply unit, which includes an acetic acid storage tank 12, a cyclohexene storage tank 11 and a raw material mixing kettle 13, wherein the acetic acid storage tank 12 and the cyclohexene storage tank 11 are respectively connected to the raw material mixing kettle 13, and the raw material mixing kettle 13 is connected to the first mixing section 110, and is used to mix acetic acid and cyclohexene and then transport them to the first mixing section 110. In addition, the cyclohexene storage tank 11 is also connected to the second mixing section 140, so as to facilitate the transport of cyclohexene discharged from the second mixing section 140 to the cyclohexene storage tank 11 for recycling, so as to reduce the generation of by-products and further improve the reaction efficiency and selectivity.

[0054] In order to further improve the reaction efficiency of cyclohexyl acetate, the raw material supply unit preferably further includes a heater 14, which is disposed on the pipeline between the raw material mixing kettle 13 and the first mixing section 110, and is used to heat the mixture of acetic acid and cyclohexene before conveying it to the first mixing section 110. The temperature of the feed reaction liquid is controlled by arranging a heat exchanger to prevent the feed from being too low in temperature, causing the reaction rate of the front section of the first reactor 100 to be slow, and the conversion rate to be too low, causing the separation capacity of the first separation section 130 to be insufficient, thereby increasing the pressure drop of the reactor 100 and affecting the stability of the feed and discharge flow rates, so that the system provided by the present application is more suitable for situations where the ambient temperature changes greatly.

[0055] Preferably, the raw material supply unit further includes a circulating water storage tank 15 , which is connected to the heater 14 and is used to transport circulating water into the heater 14 .

[0056] In order to facilitate the storage of products, it is preferred that the above-mentioned system for continuously preparing cyclohexyl acetate also includes a product collecting unit, which includes a cyclohexyl acetate product temporary storage tank 30, and the cyclohexyl acetate product temporary storage tank 30 is connected to the liquid phase outlet of the gas-liquid separator 20, and a first acetic acid removal device 31 is arranged on the pipeline between the cyclohexyl acetate product temporary storage tank 30 and the gas-liquid separator 20, and the first acetic acid removal device 31 is used to remove acetic acid in the cyclohexyl acetate reaction liquid, further reduce impurities, and improve the selectivity of the cyclohexyl acetate product; the cyclohexyl acetate product temporary storage tank 30 is also connected to the top of the reactor 100, and is used to transport the vapor-phase reactants separated by the second separation section 160 to the cyclohexyl acetate product temporary storage tank 30, and a condenser 33 is also arranged on the pipeline between the cyclohexyl acetate product temporary storage tank 30 and the reactor 100, and is used to condense the vapor-phase reactants and then transport them to the cyclohexyl acetate product temporary storage tank 30 for storage. Prevent the temperature of the vapor phase reactants from being too high, causing local vaporization of the liquid, which can lead to excessive pressure in the temporary storage tank, excessive mist and foam caused by gas-liquid mixing, and cavitation in the conveying device, etc.

[0057] Preferably, the cyclohexyl acetate product temporary storage tank 30 is provided with a third vent valve 35 to further improve the safety of the cyclohexyl acetate product temporary storage tank 30 .

[0058] Preferably, the first acetic acid removal device 31 is connected to a first acetic acid reaction liquid storage tank 32 for storing gaseous acetic acid discharged from the first acetic acid removal device 31 .

[0059] In order to further reduce the acetic acid content in cyclohexyl acetate, the product collection unit preferably also includes a second acetic acid removal device 34, which is connected to the cyclohexyl acetate product temporary storage tank 30 and is used to remove the acetic acid in the cyclohexyl acetate product again and then return it to the cyclohexyl acetate product temporary storage tank 30 for storage.

[0060] Preferably, the second acetic acid removal device 34 is connected to a second acetic acid reaction liquid storage tank 36 for storing gaseous acetic acid discharged from the second acetic acid removal device 34 .

[0061] In a second typical embodiment of the present application, a method for continuously preparing cyclohexyl acetate is also provided. The method is carried out using any system for continuously preparing cyclohexyl acetate provided in the first typical embodiment. The method comprises: mixing cyclohexyl acetate and acetic acid and passing them into a reactor 100, and sequentially passing through a first mixing section 110, a first reaction section 120, a first separation section 130, a second mixing section 140, a second reaction section 150 and a second separation section 160, and collecting cyclohexyl acetate reaction liquid from the first separation section 130 and the second separation section 160, respectively.

[0062] By applying the technical solution of the present application, the method for continuously preparing cyclohexyl acetate provided by the present application comprises the following steps: mixing cyclohexene and acetic acid and passing them into a reactor 100, and sequentially passing them through a first mixing section 110, a first reaction section 120, a first separation section 130, a second mixing section 140, a second reaction section 150, and a second separation section 160, and collecting cyclohexyl acetate reaction liquid from the first separation section 130 and the second separation section 160, respectively, so that cyclohexyl acetate is converted and separated more thoroughly, the equipment investment and energy consumption of subsequent separation are reduced, and the conversion rate is increased.

[0063] In addition, the method for continuously preparing cyclohexyl acetate provided in the present application can realize the continuous reaction of acetic acid and cyclohexene by mixing cyclohexene and acetic acid and flowing them through the first mixing section 110, the first reaction section 120, the first separation section 130, the second mixing section 140, the second reaction section 150 and the second separation section 160 in sequence, which is more in line with the reaction kinetics, increases the reaction rate, reduces the circulation time of cyclohexene in the reactor 100, and removes the generated cyclohexyl acetate reaction liquid in stages, so as to achieve a cyclohexene conversion rate of ≥99%. At the same time, it can also reduce the generation of by-products, improve selectivity, and enhance the advantages and feasibility of the process.

[0064] The purity of the cyclohexene and acetic acid is not specifically limited, and the purity of the cyclohexene and acetic acid can be any purity ranging from 10 to 99.99%.

[0065] In order to further improve the selectivity, it is preferred to first mix acetic acid and cyclohexene into a feed reaction liquid and then introduce it into the reactor 100. In the feed reaction liquid, the mass content of acetic acid is 20-95%, and the mass content of cyclohexene is 5-80%. In particular, when the mass ratio of acetic acid to cyclohexene is 5:0.5-5, it is more conducive to reducing the generation of by-products, improving the reaction efficiency and the selectivity of cyclohexyl acetate.

[0066] In order to further improve the reaction efficiency and reduce the residence time of cyclohexene in the reactor 100, the temperature of the feed reaction liquid is preferably 30-80° C. Preferably, cyclohexene and acetic acid are mixed in the raw material mixing kettle 13 and heated to 30-80° C. by a heat exchanger before being introduced into the reactor 100.

[0067] In order to further improve the conversion rate of cyclohexene, it is preferred that the residence time of the feed reaction liquid in the first reaction section 120 is 5 to 60 minutes.

[0068] In order to further improve the reaction efficiency of the first reaction section 120 and the second reaction section 150 and improve the preparation efficiency of cyclohexyl acetate, it is preferred that the reaction temperature of the first reaction section 120 and the second reaction section 150 are both 60-100° C. and the pressure are both 0.1-5 MPa.

[0069] In order to further improve the conversion rate of cyclohexene, it is preferred that the temperature of the first separation section 130 and the second separation section 160 are both 80-140°C.

[0070] Typically but not limiting, in the feed reaction liquid, the mass content of acetic acid is 20%, 31%, 42%, 53%, 64%, 75%, 85%, 95% or a range consisting of any two values; the mass content of cyclohexene is 5%, 15%, 25%, 35%, 45%, 55%, 65%, 85% or a range consisting of any two values; the mass ratio of acetic acid to cyclohexene is 5:0.5, 5:1, 5:1.5, 5:2, 5:2.5, 5:3, 5:3.5, 5:4, 5:4.5, 5:5 or a range consisting of any two values; the temperature of the feed reaction liquid is 30°C, 39°C, 48°C, 57°C, 66°C, 75°C, 80°C or a range consisting of any two values; the residence time of the feed reaction liquid in the first reaction section 120 is 5 min, 11 min, 16 min, 22 min in, 27min, 33min, 38min, 44min, 49min, 55min, 60min or a range consisting of any two numerical values; the reaction temperatures of the first reaction section 120 and the second reaction section 150 are each independently such as 60°C, 68°C, 74°C, 80°C, 85°C, 91°C, 95°C, 100°C or a range consisting of any two numerical values, and the pressures are each independently such as 0.1MPa, 0.9MPa, 2.1MPa, 2.6MPa, 3.1MPa, 3.7MPa, 4.4MPa, 5MPa or a range consisting of any two numerical values; the temperatures of the first separation section 130 and the second separation section 160 are each independently such as 80°C, 88°C, 94°C, 100°C, 105°C, 111°C, 118°C, 126°C, 140°C or a range consisting of any two numerical values.

[0071] In order to further improve the purity of cyclohexyl acetate in the cyclohexyl acetate reaction liquid, the above method preferably further comprises purifying the cyclohexyl acetate reaction liquid. Preferably, the purification comprises performing gas-liquid separation on the cyclohexyl acetate reaction liquid to obtain a vapor phase reactant and a liquid phase reaction liquid.

[0072] In order to further reduce impurities in the cyclohexyl acetate reaction solution, it is preferred that the purification further comprises removing acetic acid from the liquid phase reaction solution to obtain acetic acid.

[0073] Preferably, the acetic acid removal comprises a first removal and a second removal performed sequentially to further improve the purity of the acetic acid.

[0074] In some embodiments of the present application, the method for continuously preparing cyclohexyl acetate comprises the following steps:

[0075] (1) After acetic acid and cyclohexene in a mass ratio of 5:0.5-5 are mixed in a raw material reactor to form a feed reaction liquid, the mixture is heated to 30-60° C. through a heater 14 and enters a reactor 100 from a first feed port 111 at the bottom of a first mixing section 110 and is pushed by pressure into a first reaction section 120 for reaction. The temperature of the first reaction section 120 is controlled to be 60-90° C. and the pressure is controlled to be 0.1-5 MPa. After staying for 5-60 minutes, the mixture rises to a first separation section 130 for separation to obtain a vapor phase reactant and a cyclohexyl acetate reaction liquid.

[0076] (2) The vaporized reactants continue to rise to the second mixing section 140. A cyclohexene discharge port 142 is provided at the bottom of the second mixing section 140. The unreacted cyclohexene is passed into the cyclohexene storage tank 11 through the cyclohexene discharge port 142 for further recycling. The remaining vaporized reactants rise to the second reaction section 150 for further reaction. The temperature of the second reaction section 150 is controlled to be 60 to 90° C. and the pressure is 0.1 to 5 MPa. After staying for 5 to 60 minutes, the reactants rise to the second separation section 160 for separation to obtain vapor phase reactants and cyclohexyl acetate reaction liquid.

[0077] (3) The cyclohexyl acetate reaction liquid is first introduced into a gas-liquid separator 20 for gas-liquid separation, and the vapor phase reactants entrained in the cyclohexyl acetate reaction liquid are removed to obtain a liquid phase reaction liquid.

[0078] (4) After the first acetic acid removal from the liquid reaction liquid, the liquid reaction liquid is stored in a cyclohexyl acetate product storage tank. Meanwhile, the vapor phase reactants discharged from the second separation section 160 of the reactor 100 are condensed and also transported to the cyclohexyl acetate product storage tank. After the acetic acid in the cyclohexyl acetate product tank is removed for a second time, the acetic acid is returned to the cyclohexyl acetate product storage tank to obtain a cyclohexyl acetate product.

[0079] In the above embodiment, acetic acid and cyclohexene rise in the first reaction section 120, react in the reaction area formed by the catalyst separation filler of the first reaction section 120, and then rise to the first separation section 130 for separation. The first separation section 130 can obtain cyclohexyl acetate reaction liquid and vapor-phase reactants; most of the vapor-phase reactants rise and enter the second mixing section 140, and the cyclohexyl acetate reaction liquid carries a small part of the vapor-phase reactants into the gas-liquid separator 20, and the separated vapor-phase reactants are returned to the second mixing section 140, and the cyclohexyl acetate reaction liquid enters the first separation section 130, and the vapor-phase reactants remove the unreacted Cyclohexene is discharged and transported to the cyclohexene storage tank 11 for recycling, and the remaining vaporized gas phase continues to rise to the second reaction section 150 under pressure to react, and then enters the second separation section 160 for separation to obtain cyclohexyl acetate reaction liquid and vapor phase reactants. The vaporized reactants are condensed and transported to the cyclohexyl acetate product temporary storage tank 30. The cyclohexyl acetate reaction liquid carrying the vapor phase reactants enters the gas-liquid separator 20, and is mixed with the cyclohexyl acetate reaction liquid discharged from the first separation section 130 for gas-liquid separation, and the vapor phase reactants return to the second mixing section 140 for further reaction. The above process can obtain a liquid phase reaction liquid and a vapor phase reactant.

[0080] The beneficial effects of the present application will be further illustrated below in combination with embodiments and comparative examples.

[0081] Example 1

[0082] This embodiment provides a system for continuously preparing cyclohexyl acetate. Figure 1 As shown, the system includes a raw material supply unit, a reaction unit and a product collection unit. Figure 2 As shown, the reaction unit includes a reactor 100, and the reactor 100 includes a cylinder, and the interior of the cylinder is provided with a first mixing section 110, a first reaction section 120, a first separation section 130, a second mixing section 140, a second reaction section 150 and a second separation section 160 from bottom to top, wherein the first reaction section 120 and the second reaction section 150 are both filled with catalysts, and the first separation section and the second separation section 160 are both provided with separation fillers.

[0083] like Figure 2As shown, in the reactor 100 provided in this embodiment, a first fluid distributor 121 is provided between the first mixing section 110 and the first reaction section 120, and the first fluid distributor 121 is provided at the lower part of the first reaction section 120, a second fluid distributor 151 is provided between the second mixing section 140 and the second reaction section 150, and the second fluid distributor 151 is provided at the lower part of the second reaction section 150, so as to facilitate a more uniform dispersion of the raw material liquid to be reacted entering the first reaction section 120 and the second reaction section 150. A first reaction liquid discharge port 131 is provided at the top of the first separation section 130, and a second reaction liquid discharge port 161 is provided at the top of the second separation section 160.

[0084] In the reactor 100 , a first waste liquid discharge port 123 is disposed at the top of the first reaction section 120 , and a second waste liquid discharge port 153 is disposed at the top of the second reaction section 150 for discharging waste liquid.

[0085] The first reaction section 120 and the second reaction section 150 are both provided with a temperature controller and a pressure sensor to facilitate controlling the temperature and pressure inside the first reaction section 120 and / or the second reaction section 150, thereby improving the reaction efficiency and reducing the residence time of the raw material liquid to be reacted.

[0086] In order to further improve the selectivity of cyclohexyl acetate, a first discharge port 132 is provided at the bottom of the first separation section 130 , and a second discharge port 162 is provided at the bottom of the second separation section 160 .

[0087] The first mixing section 110 is provided with a first feed port 111 for conveying a mixed liquid of cyclohexene and acetic acid. A third waste liquid discharge port 171 is also provided at the bottom of the first mixing section 110. The second mixing section 140 is provided with a second feed port 141 for replenishing cyclohexene.

[0088] The reaction cylinder includes an upper head 180 and a lower head 170. The upper head 180 is arranged at the top of the second reaction section 150, and the upper head 180 is provided with a first vent valve port 181, the first vent valve port 181 is connected to the first vent valve 190, and the third waste liquid discharge port 171 is arranged on the lower head 170.

[0089] like Figure 1 As shown, the reaction unit also includes a gas-liquid separator 20, which has a first inlet and a second inlet, the first inlet is connected to the first reaction liquid discharge outlet 131 of the first separation section 130, the second inlet is connected to the second reaction liquid discharge outlet 161 of the second separation section 160, and the gas phase outlet of the gas-liquid separator 20 is connected to the second mixing section 140 to return the vapor phase reactant separated by the gas-liquid separator 20 to the second mixing section 140 to continue the reaction.

[0090] A second vent valve 21 is provided on the top of the gas-liquid separator 20 to further improve the safety of the gas-liquid separator 20 .

[0091] like Figure 1 As shown, the raw material supply unit includes an acetic acid storage tank 12, a cyclohexene storage tank 11 and a raw material mixing kettle 13, wherein the acetic acid storage tank 12 and the cyclohexene storage tank 11 are respectively connected to the raw material mixing kettle 13, and the raw material mixing kettle 13 is connected to the first mixing section 110, and is used to mix acetic acid and cyclohexene and then transport them to the first mixing section 110. In addition, the cyclohexene storage tank 11 is also connected to the second mixing section 140, so as to facilitate the transport of cyclohexene to the second mixing section 140, and to facilitate the control of the ratio of cyclohexene to acetic acid in the second reaction section 150, so as to further improve the reaction efficiency and selectivity.

[0092] The raw material supply unit further includes a heater 14 , which is disposed on a pipeline between the raw material mixing kettle 13 and the first mixing section 110 . The heater 14 is used to heat the mixture of acetic acid and cyclohexene before transporting it to the first mixing section 110 .

[0093] The raw material supply unit further includes a circulating water storage tank 15 , which is connected to the heater 14 and is used to transport circulating water into the heater 14 .

[0094] like Figure 1 As shown, the product collection unit includes a cyclohexyl acetate product temporary storage tank 30, which is connected to the liquid phase outlet of the gas-liquid separator 20, and a first acetic acid removal device 31 is arranged on the pipeline between the cyclohexyl acetate product temporary storage tank 30 and the gas-liquid separator 20, and the first acetic acid removal device 31 is used to remove acetic acid in the cyclohexyl acetate reaction liquid, further reduce impurities, and improve the selectivity of the cyclohexyl acetate product; the cyclohexyl acetate product temporary storage tank 30 is also connected to the top of the reactor 100, and is used to transport the vapor phase reactant to the cyclohexyl acetate product temporary storage tank 30, and a condenser 33 is also arranged on the pipeline between the cyclohexyl acetate product temporary storage tank 30 and the reactor 100, and is used to condense the vapor phase reactant into a liquid phase reaction liquid and then return it to the reactor 100.

[0095] The cyclohexyl acetate product temporary storage tank 30 is provided with a third vent valve 35 to further improve the safety of the cyclohexyl acetate product temporary storage tank 30 .

[0096] The first acetic acid removal device 31 is connected to a first acetic acid storage tank 12 for storing gaseous acetic acid discharged from the first acetic acid removal device 31 .

[0097] The product collection unit also includes a second acetic acid removal device 34, which is connected to the cyclohexyl acetate product temporary storage tank 30 and is used to remove acetic acid from the cyclohexyl acetate product again and then return it to the cyclohexyl acetate product temporary storage tank 30 for storage.

[0098] The second acetic acid removal device 34 is connected to a second acetic acid storage tank 12 for storing gaseous acetic acid discharged from the second acetic acid removal device 34 .

[0099] The product collection unit further includes frequency conversion components arranged in the first acetic acid removal device 31 and the second acetic acid removal device 34. The frequency conversion components are connected to the flange level gauge signals on the gas-liquid separator 20 and the cyclohexyl acetate product temporary storage tank 30 to achieve the linkage adjustment of the discharge flow and the liquid level.

[0100] Example 2

[0101] The difference between this embodiment and the first embodiment is that the heater 14 is not provided on the pipeline between the raw material mixing kettle 13 and the first mixing section 110 .

[0102] Example 3

[0103] The difference between this embodiment and embodiment 1 is that the condenser 33 is not provided on the pipeline between the cyclohexyl acetate product temporary storage tank 30 and the reactor 100 .

[0104] Comparative Example 1

[0105] The difference between this comparative example and Example 1 is that the first mixing section 110 and the second mixing section 140 are not disposed inside the reactor 100 .

[0106] Comparative Example 2

[0107] The difference between this comparative example and Example 1 is that the second separation section 160 is not provided inside the reactor 100 .

[0108] Comparative Example 3

[0109] The difference between this comparative example and Example 1 is that the second reaction section 150 is not disposed inside the reactor 100 .

[0110] Example 4

[0111] This embodiment provides a method for continuously preparing cyclohexyl acetate, which is carried out using the system for continuously preparing cyclohexyl acetate provided in Example 1, and specifically comprises the following steps:

[0112] (1) After acetic acid and cyclohexene are mixed in a raw material reactor to form a feed reaction liquid (the mass content of acetic acid is 58.6%, the mass content of cyclohexene is 41.1%, and the remainder is impurities), the mixture is heated to 45° C. by a heater 14 and passed into a first mixing section 110 at a pressure of 1.0 MPa. After mass transfer mixing in the first mixing section 110 and the first mixing section 110, the mixture rises to a first reaction section 120 for reaction. The temperature and pressure of the first reaction section 120 are controlled to be 75° C. and 0.12 MPa. After staying for 15 minutes, the mixture rises to a first separation section 130 for separation. The temperature of the first separation section 130 is 120° C., thereby obtaining a vapor phase reactant and a cyclohexyl acetate reaction liquid.

[0113] (2) The vaporized reactants continue to rise to the second mixing section 140, and then rise to the second reaction section 150 to continue the refining reaction. The temperature of the second reaction section 150 is controlled to be 80° C. and the pressure is controlled to be 0.1 MPa. After staying for 30 minutes, the reactants rise to the second separation section 160 for separation. The temperature of the second separation section 160 is 120° C., and a vapor phase reactant and a cyclohexyl acetate reaction liquid are obtained.

[0114] (3) The cyclohexyl acetate reaction liquid is first introduced into a gas-liquid separator 20 for gas-liquid separation, and the vapor phase reactants entrained in the cyclohexyl acetate reaction liquid are removed to obtain a liquid phase reaction liquid.

[0115] (4) After the first acetic acid removal from the liquid reaction liquid, the liquid reaction liquid is stored in a cyclohexyl acetate product storage tank. Meanwhile, the vapor phase reactants discharged from the second separation section 160 in the reactor 100 are condensed to 50° C. and then transported to the cyclohexyl acetate product storage tank. After the acetic acid in the cyclohexyl acetate product tank is removed for a second time, the acetic acid is returned to the cyclohexyl acetate product storage tank to obtain a cyclohexyl acetate product.

[0116] Example 5

[0117] The difference between this embodiment and embodiment 4 is that in step (1), the mass content of acetic acid in the feed reaction liquid is 59.1%, the mass content of cyclohexene is 40.0%, and the remainder is impurities, and the feed reaction liquid is heated to 50° C. by the heater 14 and then transported to the reactor 100, and the temperature of the first reaction section 120 is controlled to be 60° C.

[0118] In step (4), the vapor phase reactants discharged from the second separation section 160 in the reactor 100 are condensed to 40° C. and then transported to the cyclohexyl acetate product storage tank.

[0119] Example 6

[0120] The difference between this embodiment and embodiment 4 is that in step (1), the mass content of acetic acid in the feed reaction liquid is 40%, the mass content of cyclohexene is 59.7%, and the remainder is impurities, and the feed reaction liquid is heated to 45° C. by heater 14 and then transported to reactor 100.

[0121] In step (4), the vapor phase reactants discharged from the second separation section 160 in the reactor 100 are condensed to 40° C. and then transported to the cyclohexyl acetate product storage tank.

[0122] Example 7

[0123] The difference between this embodiment and embodiment 4 is that in step (1), the mass content of acetic acid in the feed reaction liquid is 59.1%, the mass content of cyclohexene is 40.2%, and the remainder is impurities, and the feed reaction liquid is heated to 45° C. by the heater 14 and then transported to the reactor 100, and the residence time of the feed reaction liquid in the first reaction section 120 is 5 minutes; the residence time of the vapor phase reactant obtained after separation in the first separation section 130 in the second reaction section 150 is also 5 minutes.

[0124] In step (4), the vapor phase reactants discharged from the second separation section 160 in the reactor 100 are condensed to 40° C. and then transported to the cyclohexyl acetate product storage tank.

[0125] Example 8

[0126] The difference between this embodiment and embodiment 4 is that in step (1), the feed reaction liquid is heated to 30° C. and transported to the first mixing section 110 .

[0127] Example 9

[0128] The difference between this embodiment and embodiment 4 is that in step (1), the feed reaction liquid is heated to 80° C. and then transported to the first mixing section 110 .

[0129] Example 10

[0130] The difference between this embodiment and embodiment 4 is that the residence time of the feed reaction liquid in the first reaction section 120 is 60 minutes, and the residence time of the vapor phase reactants separated in the first separation section 130 in the second reaction section 150 is also 60 minutes.

[0131] Embodiment 11

[0132] The difference between this embodiment and embodiment 4 is that the temperature of the first reaction section 120 and the second reaction section 150 are both 100°C, the pressure is both 5 MPa, and the temperature of the first separation section 130 and the second separation section 160 are both 140°C.

[0133] Example 12

[0134] The difference between this embodiment and embodiment 4 is that the temperature of the first reaction section 120 and the second reaction section 150 are both 60°C, the pressure is both 0.1 MPa, and the temperature of the first separation section 130 and the second separation section 160 are both 80°C.

[0135] Example 13

[0136] The difference between this embodiment and embodiment 4 is that the system provided in embodiment 2 is used to carry out the method for continuously preparing cyclohexyl acetate.

[0137] Embodiment 14

[0138] The difference between this embodiment and embodiment 4 is that the system provided in embodiment 3 is used to continuously prepare cyclohexyl acetate.

[0139] Comparative Example 4

[0140] The difference between this embodiment and embodiment 4 is that the system provided in comparative example 1 is used to continuously prepare cyclohexyl acetate.

[0141] Comparative Example 5

[0142] The difference between this embodiment and embodiment 4 is that the system provided in comparative example 2 is used to continuously prepare cyclohexyl acetate.

[0143] Comparative Example 6

[0144] The difference between this embodiment and embodiment 4 is that the system provided in comparative example 3 is used to continuously prepare cyclohexyl acetate.

[0145] Test Example 1

[0146] The content of the substance types in the vapor phase reactant condensate discharged from the reactor in the above-mentioned embodiment and comparative example, as well as the content of cyclohexyl acetate and the content of by-products in the cyclohexyl acetate product were detected by gas chromatography quantitative analysis method, and the results are shown in Table 1. The cyclohexene conversion rate and the cyclohexyl acetate yield were calculated based on the mass of the cyclohexyl acetate product and the mass of cyclohexene, and the results are shown in Table 2.

[0147] Table 1

[0148]

[0149] Table 2

[0150]

[0151]

[0152] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0153] The system for continuously preparing cyclohexyl acetate of the present application designs a reactor 100 with multiple-stage reactions and separations connected in series, and sets up related auxiliary process equipment systems to obtain cyclohexyl acetate with high purity. By controlling the reaction conditions, the purity can reach more than 99%; the use of multiple-pass reactions makes the yield of cyclohexyl acetate high, which can reach more than 99%; at the same time, by controlling the residence time and separation temperature of the two-stage reactions and adding a gas-liquid separation device, the generation of lower by-products can be achieved, and the selectivity of cyclohexyl acetate reaches more than 99%; the use of this system also reduces the equipment required for subsequent separation, reduces investment, and improves the economic efficiency of the product.

[0154] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A system for continuously preparing cyclohexyl acetate, characterized in that: The system comprises a reaction unit, wherein the reaction unit comprises a reactor (100), wherein the reactor (100) comprises a cylinder, wherein the cylinder is provided with a first mixing section (110), a first reaction section (120), a first separation section (130), a second mixing section (140), a second reaction section (150) and a second separation section (160) in sequence from bottom to top; wherein the first reaction section (120) and the second reaction section (150) are both filled with a catalyst, and the first separation section (130) and the second separation section (160) are both provided with a separation filler; The reaction unit further comprises a gas-liquid separator (20), the gas-liquid separator (20) having a first inlet and a second inlet, the first inlet being connected to the first separation section (130), the second inlet being connected to the second separation section (160), and the gas phase outlet of the gas-liquid separator (20) being connected to the second mixing section (140); The bottom of the first separation section (130) is provided with a first discharge port (132), and the bottom of the second separation section (160) is provided with a second discharge port (162); The first mixing section (110) is provided with a first feed port (111), a third waste liquid discharge port (171) is provided at the bottom of the first mixing section (110), and the second mixing section (140) is provided with a cyclohexene discharge port (142).

2. The system according to claim 1, characterized in that A first fluid distributor (121) is provided between the first mixing section (110) and the first reaction section (120), and a second fluid distributor (151) is provided between the second mixing section (140) and the second reaction section (150); And / or, a first waste liquid discharge port (123) is provided at the top of the first reaction section (120), and a second waste liquid discharge port (153) is provided at the top of the second reaction section (150); and both the first reaction section (120) and the second reaction section (150) are provided with a temperature controller and a pressure sensor.

3. The system according to claim 1 or 2, characterized in that: The system further comprises a raw material supply unit, the raw material supply unit comprising an acetic acid storage tank (12), a cyclohexene storage tank (11) and a raw material mixing kettle (13), the acetic acid storage tank (12) and the cyclohexene storage tank (11) are respectively connected to the raw material mixing kettle (13), the raw material mixing kettle (13) is connected to the first mixing section (110), the raw material mixing kettle (13) is used to mix acetic acid and cyclohexene and then transport them to the first mixing section (110), and the cyclohexene storage tank (11) is also connected to the second mixing section (140).

4. The system according to claim 3, characterized in that The raw material supply unit further comprises a heater (14), and the heater (14) is arranged on the pipeline between the raw material mixing kettle (13) and the first mixing section (110).

5. The system according to claim 1 or 2, characterized in that: The system further comprises a product collection unit, the product collection unit comprising a cyclohexyl acetate product temporary storage tank (30), the cyclohexyl acetate product temporary storage tank (30) being connected to the liquid phase outlet of the gas-liquid separator (20), and a first acetic acid removal device (31) being further provided on the pipeline between the cyclohexyl acetate product temporary storage tank (30) and the gas-liquid separator (20); the cyclohexyl acetate product temporary storage tank (30) being further connected to the top of the reactor (100), and a condenser (33) being further provided on the pipeline between the cyclohexyl acetate product temporary storage tank (30) and the reactor (100).

6. The system according to claim 5, characterized in that The product collection unit further comprises a second acetic acid removal device (34), and the second acetic acid removal device (34) is connected to the cyclohexyl acetate product temporary storage tank (30).

7. A method for continuously preparing cyclohexyl acetate, characterized in that: The method is performed using the system according to any one of claims 1 to 6, and the method comprises: Cyclohexene and acetic acid are mixed and introduced into a reactor (100), and flow through a first mixing section (110), a first reaction section (120), a first separation section (130), a second mixing section (140), a second reaction section (150) and a second separation section (160) in sequence, and cyclohexyl acetate reaction liquid is collected from the first separation section (130) and the second separation section (160), respectively.

8. The method according to claim 7, characterized in that The method further comprises purifying the cyclohexyl acetate reaction solution.

9. The method according to claim 8, characterized in that The purification includes performing gas-liquid separation on the cyclohexyl acetate reaction liquid to obtain a vapor phase reactant and a liquid phase reaction liquid.

10. The method according to claim 9, characterized in that The purification also includes removing acetic acid from the liquid phase reaction solution to obtain a cyclohexyl acetate product.

11. The method according to any one of claims 7 to 10, characterized in that Acetic acid and cyclohexene are first mixed into a feed reaction liquid and then introduced into the reactor (100). The mass content of acetic acid in the feed reaction liquid is 20-95%, and the mass content of cyclohexene is 5-80%.

12. The method according to claim 11, characterized in that The mass ratio of the acetic acid to the cyclohexene is 5:0.5-5; and / or, the temperature of the feed reaction liquid is 30 to 80° C.; And / or, the residence time of the feed reaction liquid in the first reaction section (120) is 5 to 60 minutes.

13. The method according to any one of claims 7 to 10, characterized in that The reaction temperatures of the first reaction section (120) and the second reaction section (150) are both 60-100°C, and the pressures are both 0.1-5 MPa; And / or, the temperature of the first separation section (130) and the second separation section (160) are both 80-140°C.

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