A novel sec-butyl acetate production device and production process

Abstract

The application discloses a novel sec-butyl acetate production device and production process, and relates to the technical field of organic chemical industry and chemical process technology. The application takes a catalytic distillation tower as a core, integrates a two-section esterification reactor, a C4 deacidification tower, an azeotropic distillation tower, a sec-butyl acetate product tower and a de-acetic acid tower, and adopts a solid acid catalyst to reduce corrosion and pollution, utilizes catalytic distillation to strengthen reaction balance, improves conversion rate, optimizes tower operation conditions, simplifies a process and reduces energy consumption, realizes efficient, clean and low-cost production of sec-butyl acetate, and meets the increasing demand of the market for environment-friendly solvents.

Description

Technical Field

[0001] This invention relates to the field of organic chemical engineering and chemical process technology, and more specifically to a novel sec-butyl acetate production apparatus and production process. Background Technology

[0002] sec-butyl acetate, also known as tert-butyl acetate, has the molecular formula CH3COOCH(CH3)CH2CH3 and a molecular weight of 116.16. It is an important organic chemical product widely used as a solvent in oils, resins, coatings, paints, reaction processes, extraction and separation processes, and in the formulation of metal cleaning agents and fragrances. In recent years, due to stricter environmental regulations, the use of toxic solvents such as benzene, toluene, and ketones has been gradually restricted, leading to a sharp increase in the use of environmentally friendly solvents such as sec-butyl acetate. Therefore, sec-butyl acetate has a broad market prospect.

[0003] There are two methods for producing sec-butyl acetate: alcohol esterification and olefin acetic acid addition. The former includes the esterification reaction of sec-butanol and acetic acid, as well as the reaction of sec-butanol with acetic anhydride, both of which have existing industrial production facilities.

[0004] Alcohol esterification is the process of dehydrating and esterifying sec-butanol and acetic acid under the action of an acidic catalyst to synthesize sec-butyl acetate. The catalyst is a strong acid, and the acids that can be used include sulfuric acid, p-toluenesulfonic acid, and sulfonic acid-type cation exchange resins. Due to its low price and high activity, sulfuric acid is widely used in industry. This method has the following disadvantages: (1) The esterification reaction uses sulfuric acid as a catalyst, which severely corrodes the equipment. After the reaction, the sulfuric acid needs to be neutralized and the product needs to be washed with water, which generates a large amount of wastewater and seriously pollutes the environment; (2) Alcohols are generally obtained by hydration or hydroformylation-hydrogenation of olefins, which results in high raw material costs.

[0005] The acetic acid addition method for olefins involves the direct synthesis of butene through the addition reaction of anhydrous glacial acetic acid with an acidic catalyst. The catalysts used in this synthesis can include solid acid catalysts and liquid acid catalysts; the former includes cation exchange resins and heteropoly acids, while the latter includes sulfuric acid and p-toluenesulfonic acid.

[0006] The synthesis of sec-butyl acetate in the existing technology mainly has the following problems: First, the reaction is reversible and the conversion rate is limited, resulting in low utilization of raw materials; second, traditional catalysts (such as concentrated sulfuric acid) severely corrode equipment and generate waste acid, causing great environmental pollution; third, the water generated in the reaction needs to be removed in time, making the process operation complicated; and fourth, there are many product separation and purification steps, resulting in high energy consumption. Summary of the Invention

[0007] This invention aims to solve the technical problems in existing sec-butyl acetate production processes, such as severe corrosion of equipment by traditional sulfuric acid catalysts, large amounts of wastewater pollution, low raw material utilization due to reversible reactions, difficult and complex operation for removing reaction water, and high energy consumption for product separation and purification. By providing a new process centered on a catalytic distillation column, integrating a two-stage esterification reactor, a C4 deacidification column, an azeotropic distillation column, a sec-butyl acetate product column, and a deacetic acid removal column, this invention aims to reduce corrosion and pollution by using solid acid catalysts, enhance reaction equilibrium and improve conversion rate through catalytic distillation, optimize column operating conditions to simplify the process and reduce energy consumption, thereby achieving efficient, clean, and low-cost production of sec-butyl acetate and meeting the growing market demand for environmentally friendly solvents.

[0008] This invention innovates a process system that uses a solid acid catalyst to replace the traditional liquid acid, couples the reaction and separation through a catalytic distillation column to enhance the process, and integrates multiple columns for purification. It is suitable for the large-scale clean production of sec-butyl acetate, which is used as an environmentally friendly solvent, metal cleaning agent, and fragrance intermediate.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] A novel sec-butyl acetate production apparatus includes: a two-stage esterification reactor, a catalytic distillation column, a C4 deacidification column, an azeotropic distillation column, a sec-butyl acetate product column, and a deacetic acid removal column. The two-stage esterification reactor includes a first-stage esterification reactor and a second-stage esterification reactor; The first-stage esterification reactor, the second-stage esterification reactor, and the catalytic distillation column are connected in sequence. The top of the catalytic distillation column is connected to the C4 deacidification column, and the bottom of the column is connected to the azeotropic distillation column. The top of the azeotropic distillation column is connected to the butyl acetate product column, and the bottom of the column is connected to the deacetic acid removal column.

[0011] Preferably, the above-mentioned apparatus further includes: a mixer; The mixer is connected to the first-stage esterification reactor.

[0012] Preferably, the above-mentioned apparatus further includes: a C11 deacidification tank; The C11 deacidification tank is connected to the bottom of the deacetic acid removal tower.

[0013] Preferably, the catalytic distillation column, azeotropic distillation column, sec-butyl acetate product column, and deacetic acid removal column are all equipped with a top reboiler and a bottom reboiler.

[0014] Another object of the present invention is to provide a novel process for producing sec-butyl acetate, using the above-described apparatus, comprising the following steps: (1) Acetic acid and mixed C4 are first mixed and then fed into a first-stage esterification reactor and a second-stage esterification reactor in sequence, and sec-butyl acetate is generated through two-stage reaction; (2) The outlet material of the two-stage esterification reactor enters the catalytic distillation column, where the olefins in the rising C4 react with the supplemented acetic acid. (3) Unreacted C4 at the top of the catalytic distillation tower enters the lower part of the C4 deacidification tower and is fed with water at the top of the C4 deacidification tower. It is in countercurrent contact in the C4 deacidification tower. C4 product is obtained at the top of the tower, and the water in the bottom of the tower is sent to the external sewage treatment system. (4) The bottom material of the catalytic distillation column and the supplementary acetic acid enter the azeotropic distillation column. The top material of the azeotropic distillation column enters the sec-butyl acetate product column. C8 is obtained at the top of the column, and sec-butyl acetate is extracted from the side stream. The bottom of the column is a mixture of C12 and sec-butyl acetate, which is discharged intermittently. (5) The bottom material of the azeotropic distillation column enters the deacetic acid tower. The acetic acid at the top of the deacetic acid tower is recycled back to the reaction system. The bottom material is deacidified by the C12 deacidification tank to obtain C12 product. The waste alkali liquid is sent out of the system.

[0015] Preferably, the operating conditions of the first-stage esterification reactor are: reaction temperature 70~90℃, reaction pressure 1.5~2.0MPa, acetic acid to butene molar ratio of 1.1~2.0:1, and the resin catalyst packed is D-005Ⅱ.

[0016] The operating conditions of the two-stage esterification reactor are as follows: reaction temperature 80~100℃, reaction pressure 1.5~2.0MPa, total olefin molar ratio in acetic acid and C4 1.1~2.0:1, and the resin catalyst used is D-009.

[0017] Preferably, the operating conditions of the catalytic distillation column are: top temperature 50~60℃, top pressure 0.5~0.6MPa, number of trays 50~70, feed inlet position 30~40, reflux ratio 1~3:1, 8~10 reaction sections packed in the reaction section, and the resin catalyst packed in is D-005Ⅱ.

[0018] Preferably, the operating conditions of the C4 deacidification tower are: tower top temperature 38~42℃, pressure 0.39~0.41MPa, wherein the molar ratio of water to C4 is 0.5~10:1, and the number of tower trays is 40~60.

[0019] The operating conditions of the azeotropic distillation column are as follows: 60-90 trays, feed inlet position 20-30, top temperature 90-100℃, top pressure 0.02-0.07MPa, and reflux ratio 1-5.

[0020] Preferably, the operating conditions of the sec-butyl acetate product tower are: 60-90 trays, 100-110°C top temperature, 0.02-0.07 MPa top pressure, 5-20 reflux ratio, and 6-10 tray position of the side stream outlet.

[0021] Preferably, the operating conditions of the acetic acid removal tower are: 20-30 trays, 10-15 feed inlets, 125-130°C top temperature, 0.02-0.03 MPa top pressure, and 0.5-2.0 reflux ratio.

[0022] As can be seen from the above technical solution, compared with the prior art, the present invention has the following technical effects: This invention significantly improves reaction efficiency through overall design. It employs a two-stage esterification reactor, each filled with a specialized solid acid resin catalyst adapted to different temperature ranges, fully utilizing the temperature effect to synergistically enhance reaction conversion and product selectivity. The core catalytic distillation column precisely controls the temperature gradient and vapor-liquid phase equilibrium within the column, achieving enhanced coupling between reaction and separation, further overcoming reaction equilibrium limitations and significantly increasing butene conversion. Subsequent azeotropic distillation, product column, and deacetic acid removal column optimize the separation process, achieving efficient purification of sec-butyl acetate and byproduct recovery, while reducing system energy consumption. The entire process uses non-corrosive solid acid catalysts, solving equipment corrosion and wastewater pollution problems at the source, enabling clean, efficient, and low-cost industrial production. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0024] Figure 1 This is a structural diagram of the sec-butyl acetate production apparatus of the present invention.

[0025] In the picture: 1- Mixer; 2- First-stage esterification reactor; 3- Second-stage esterification reactor; 4- Catalytic distillation column; 5- C4 deacidification column; 6- Azeotropic distillation column; 7- Butyl acetate product column; 8- Deacetic acid column; 9- C11 deacidification column; 10- Acetic acid; 11- Mixed C4; 12- Water; 13- Make-up acetic acid. Detailed Implementation

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Example 1 This embodiment provides a novel sec-butyl acetate production apparatus, comprising: a two-stage esterification reactor, a catalytic distillation tower 4, a C4 deacidification tower 5, an azeotropic distillation tower 6, a sec-butyl acetate product tower 7, a deacetic acid tower 8, a mixer 1, and a C11 deacidification tank 9. The two-stage esterification reactor includes a first-stage esterification reactor 2 and a second-stage esterification reactor 3. Mixer 1, primary esterification reactor 2, secondary esterification reactor 3, and catalytic distillation column 4 are connected in sequence; The top of the catalytic distillation column 4 is connected to the C4 deacidification column 5, and the bottom of the column is connected to the azeotropic distillation column 6. The top of the azeotropic distillation column 6 is connected to the butyl acetate product column 7, and the bottom of the column is connected to the deacetic acid removal column 8.

[0028] The C11 deacidification tank 9 is connected to the bottom of the deacetic acid removal tower 8.

[0029] Catalytic distillation column 4, azeotropic distillation column 6, sec-butyl acetate product column 7, and deacetic acid removal column 8 are all equipped with a top reboiler and a bottom reboiler.

[0030] The process for producing sec-butyl acetate using the above-mentioned apparatus includes the following steps: (1) Acetic acid 10 and mixed C4 11 are first mixed and then successively fed into a first-stage esterification reactor 2 and a second-stage esterification reactor 3, and sec-butyl acetate is generated through two-stage reaction; (2) The outlet material of the two-stage esterification reactor 3 enters the catalytic distillation tower 4, where the rising C4 reacts with the supplemented acetic acid 13. (3) Unreacted C4 at the top of the catalytic distillation tower 4 enters the lower part of the C4 deacidification tower 5 and is fed by water 12 at the top of the C4 deacidification tower 5. It is in countercurrent contact in the C4 deacidification tower 5, and the C4 product is obtained at the top of the tower. The water in the bottom of the tower enters the external sewage treatment system. (4) The bottom material of catalytic distillation column 4 and the supplementary acetic acid 13 enter azeotropic distillation column 6. The top material of azeotropic distillation column 6 enters sec-butyl acetate product column 7. C8 is obtained at the top of the column, and sec-butyl acetate is extracted from the side stream. The bottom of the column is a mixture of C12 and sec-butyl acetate, which is discharged intermittently. (5) The bottom material of the azeotropic distillation column 6 enters the acetic acid removal column 8. The acetic acid at the top of the acetic acid removal column 8 is recycled back to the reaction system. The bottom material is deacidified by the C12 deacidification tank 9 to obtain C12 products. The waste alkali liquid is sent out of the system.

[0031] Example 2 The apparatus and method described in Example 1 are used, specifically: The operating conditions of the first-stage esterification reactor 2 are as follows: reaction temperature 70℃, reaction pressure 1.5MPa, acetic acid to butene molar ratio of 1.1:1, and resin catalyst D-005Ⅱ.

[0032] The operating conditions of the two-stage esterification reactor 3 are as follows: reaction temperature 80℃, reaction pressure 1.5MPa, total olefin molar ratio in acetic acid and C4 1.1:1, and resin catalyst D-009.

[0033] The operating conditions for catalytic distillation column 4 are: top temperature 50℃, top pressure 0.5MPa, number of trays 50, feed inlet position 30, and reflux ratio 1:1. The reaction section is filled with 8 reaction sections, and the resin catalyst used is D-005Ⅱ.

[0034] The C4 deacidification tower 5 has a top temperature of 38℃ and a pressure of 0.39MPa. The molar ratio of water to C4 is 0.5:1. Water enters from the top of the tower, while C4 enters from the bottom. The tower has 40 trays.

[0035] The azeotropic distillation column 6 has 60 trays, a feed inlet at position 20, a top temperature of 90℃, a top pressure of 0.02MPa, and a reflux ratio of 1.

[0036] The sec-butyl acetate tower 7 has 60 trays, a top temperature of 100℃, a top pressure of 0.02MPa, a reflux ratio of 5, and a side stream outlet tray position of 6.

[0037] The acetic acid removal tower 8 has 20 trays, 10 feed inlets, a top temperature of 125℃, a top pressure of 0.02MPa, and a reflux ratio of 0.5.

[0038] Acetic acid processed by the above process reacts with mixed C4 olefins to produce sec-butyl acetate, with a total C4 olefin conversion of 82.37% and a selectivity of sec-butyl acetate of 99.37%.

[0039] Example 3 The apparatus and method described in Example 1 are used, specifically: The operating conditions of the first-stage esterification reactor 2 are as follows: reaction temperature 90℃, reaction pressure 2.0MPa, acetic acid to butene molar ratio of ~2.0:1, and resin catalyst D-005Ⅱ.

[0040] The operating conditions of the two-stage esterification reactor 3 are as follows: reaction temperature 100℃, reaction pressure 2.0MPa, acetic acid to olefin molar ratio of 2.0:1, and resin catalyst D-009.

[0041] The operating conditions for catalytic distillation column 4 are: top temperature 60℃, top pressure 0.6MPa, number of trays 70, feed inlet position 40, and reflux ratio 3:1. The reaction section is packed with 10 reaction sections, and the resin catalyst used is D-005Ⅱ.

[0042] The C4 deacidification tower 5 has a top temperature of 42℃ and a pressure of 0.41MPa. The molar ratio of water to C4 is 10:1. Water enters from the top of the tower, while C4 enters from the bottom. The tower has 60 trays.

[0043] The azeotropic distillation column 6 has 90 trays, a feed inlet at position 30, a top temperature of 100℃, a top pressure of 0.07MPa, and a reflux ratio of 5.

[0044] The sec-butyl acetate tower 7 has 90 trays, a top temperature of 110℃, a top pressure of 0.07MPa, a reflux ratio of 20, and a side stream outlet tray position of 10.

[0045] The acetic acid removal tower 8 has 30 trays, a feed inlet at position 15, a top temperature of 130℃, a top pressure of 0.03MPa, and a reflux ratio of 2.0.

[0046] Acetic acid processed using the above method reacts with mixed C4 hydrocarbons to produce sec-butyl acetate, achieving a total C4 olefin conversion of 82.84% and a selectivity of 98.96% for sec-butyl acetate.

[0047] Example 4 The apparatus and method described in Example 1 are used, specifically: The operating conditions of the first-stage esterification reactor 2 are as follows: reaction temperature 80℃, reaction pressure 1.8MPa, acetic acid to butene molar ratio of 1.5:1, and resin catalyst D-005Ⅱ.

[0048] The operating conditions of the two-stage esterification reactor 3 are as follows: reaction temperature 90℃, reaction pressure 1.8MPa, acetic acid to olefin molar ratio of 1.5:1, and resin catalyst D-009.

[0049] The operating conditions for catalytic distillation column 4 are: top temperature 55℃, top pressure 0.55MPa, number of trays 60, feed inlet position 35, and reflux ratio 2:1. The reaction section is packed with 9 reaction sections, and the resin catalyst used is D-005Ⅱ.

[0050] The C4 deacidification tower 5 has a top temperature of 40℃ and a pressure of 0.40MPa. The molar ratio of water to C4 is 5:1. Water enters from the top of the tower, and C4 enters from the bottom. The tower has 50 trays.

[0051] The azeotropic distillation column 6 has 75 trays, a feed inlet at position 25, a top temperature of 95℃, a top pressure of 0.03MPa, and a reflux ratio of 3.

[0052] The sec-butyl acetate column 7 has 70 trays, a top temperature of 105℃, a top pressure of 0.04Pa, a reflux ratio of 10, and a side stream outlet tray position of 8.

[0053] The acetic acid removal tower 8 has 25 trays, 12 feed inlets, a top temperature of 127℃, a top pressure of 0.025MPa, and a reflux ratio of 1.0.

[0054] Acetic acid processed by the above process reacts with mixed C4 olefins to produce sec-butyl acetate, with a total C4 olefin conversion of 82.28% and a selectivity of sec-butyl acetate of 98.58%.

[0055] Comparative Example 1 Using the apparatus and method from Example 1 (without a reactor section), specifically: The operating conditions of the two-stage esterification reactor 3 are as follows: reaction temperature 80℃, reaction pressure 1.5MPa, acetic acid to olefin molar ratio of 1.1:1, and resin catalyst D-009.

[0056] The operating conditions for catalytic distillation column 4 are: top temperature 50℃, top pressure 0.5MPa, number of trays 50, feed inlet position 30, and reflux ratio 1:1. The reaction section is filled with 8 reaction sections, and the resin catalyst used is D-005Ⅱ.

[0057] The C4 deacidification tower 5 has a top temperature of 38℃ and a pressure of 0.39MPa. The molar ratio of water to C4 is 0.5:1. Water enters from the top of the tower, while C4 enters from the bottom. The tower has 40 trays.

[0058] The azeotropic distillation column 6 has 60 trays, a feed inlet at position 20, a top temperature of 90℃, a top pressure of 0.02MPa, and a reflux ratio of 1.

[0059] The sec-butyl acetate tower 7 has 60 trays, a top temperature of 100℃, a top pressure of 0.02MPa, a reflux ratio of 5, and a side stream outlet tray position of 6.

[0060] The acetic acid removal tower 8 has 20 trays, 10 feed inlets, a top temperature of 125℃, a top pressure of 0.02MPa, and a reflux ratio of 0.5.

[0061] Acetic acid processed by the above process reacts with mixed C4 olefins to produce sec-butyl acetate, with a total C4 olefin conversion of 73.86% and a selectivity of sec-butyl acetate of 98.15%.

[0062] Comparative Example 2 The apparatus and method described in Example 1 are used, specifically: The operating conditions of the first-stage esterification reactor 2 are as follows: reaction temperature 70℃, reaction pressure 1.5MPa, acetic acid to butene molar ratio of 1.1:1, and resin catalyst D-005Ⅱ.

[0063] The operating conditions for catalytic distillation column 4 are: top temperature 50℃, top pressure 0.5MPa, number of trays 50, feed inlet position 30, and reflux ratio 1:1. The reaction section is filled with 8 reaction sections, and the resin catalyst used is D-005Ⅱ.

[0064] The C4 deacidification tower 5 has a top temperature of 38℃ and a pressure of 0.39MPa. The molar ratio of water to C4 is 0.5:1. Water enters from the top of the tower, while C4 enters from the bottom. The tower has 40 trays.

[0065] The azeotropic distillation column 6 has 60 trays, a feed inlet at position 20, a top temperature of 90℃, a top pressure of 0.02MPa, and a reflux ratio of 1.

[0066] The sec-butyl acetate tower 7 has 60 trays, a top temperature of 100℃, a top pressure of 0.02MPa, a reflux ratio of 5, and a side stream outlet tray position of 6.

[0067] The acetic acid removal tower 8 has 20 trays, 10 feed inlets, a top temperature of 125℃, a top pressure of 0.02MPa, and a reflux ratio of 0.5.

[0068] Acetic acid processed by the above process reacts with mixed C4 olefins to produce sec-butyl acetate, with a total C4 olefin conversion of 66.81% and a selectivity of sec-butyl acetate of 98.62%.

[0069] Comparative Example 3 The apparatus and method described in Example 1 are used, specifically: The operating conditions for catalytic distillation column 4 are: top temperature 50℃, top pressure 0.5MPa, number of trays 50, feed inlet position 30, and reflux ratio 1:1. The reaction section is filled with 8 reaction sections, and the resin catalyst used is D-005Ⅱ.

[0070] The C4 deacidification tower 5 has a top temperature of 38℃ and a pressure of 0.39MPa. The molar ratio of water to C4 is 0.5:1. Water enters from the top of the tower, while C4 enters from the bottom. The tower has 40 trays.

[0071] The azeotropic distillation column 6 has 60 trays, a feed inlet at position 20, a top temperature of 90℃, a top pressure of 0.02MPa, and a reflux ratio of 1.

[0072] The sec-butyl acetate tower 7 has 60 trays, a top temperature of 100℃, a top pressure of 0.02MPa, a reflux ratio of 5, and a side stream outlet tray position of 6.

[0073] The acetic acid removal tower 8 has 20 trays, 10 feed inlets, a top temperature of 125℃, a top pressure of 0.02MPa, and a reflux ratio of 0.5.

[0074] Acetic acid processed by the above process reacts with mixed C4 olefins to produce sec-butyl acetate, with a total C4 olefin conversion of 36.88% and a selectivity of sec-butyl acetate of 90.65%.

[0075] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0076] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A novel sec-butyl acetate production apparatus, characterized in that, include: Two-stage esterification reactor, catalytic distillation column, C4 deacidification column, azeotropic distillation column, sec-butyl acetate product column, deacetic acid removal column; The two-stage esterification reactor includes a first-stage esterification reactor and a second-stage esterification reactor; The first-stage esterification reactor, the second-stage esterification reactor, and the catalytic distillation column are connected in sequence. The top of the catalytic distillation column is connected to the C4 deacidification column, and the bottom of the column is connected to the azeotropic distillation column. The top of the azeotropic distillation column is connected to the butyl acetate product column, and the bottom of the column is connected to the deacetic acid removal column.

2. The novel sec-butyl acetate production apparatus according to claim 1, characterized in that, Also includes: mixer; The mixer is connected to the first-stage esterification reactor.

3. The novel sec-butyl acetate production apparatus according to claim 2, characterized in that, Also includes: C11 deacidification tank; The C11 deacidification tank is connected to the bottom of the deacetic acid removal tower.

4. A novel sec-butyl acetate production apparatus according to claim 3, characterized in that, The catalytic distillation column, azeotropic distillation column, sec-butyl acetate product column, and deacetic acid removal column are all equipped with a top reboiler and a bottom reboiler.

5. A novel process for producing sec-butyl acetate, characterized in that, The apparatus according to claim 4 is characterized by comprising the following steps: (1) Acetic acid and mixed C4 are first mixed and then fed into a first-stage esterification reactor and a second-stage esterification reactor in sequence, and sec-butyl acetate is generated through two-stage reaction; (2) The outlet material of the two-stage esterification reactor enters the catalytic distillation column, where the olefins in the rising C4 react with the supplemented acetic acid, and the reaction is returned to the catalytic distillation column. (3) Unreacted C4 at the top of the catalytic distillation tower enters the lower part of the C4 deacidification tower and is fed with water at the top of the C4 deacidification tower. It is in countercurrent contact in the C4 deacidification tower. C4 product is obtained at the top of the tower, and the water in the bottom of the tower is sent to the external sewage treatment system. (4) The bottom material of the catalytic distillation column and the supplementary acetic acid enter the azeotropic distillation column. The top material of the azeotropic distillation column enters the sec-butyl acetate product column. C8 is obtained at the top of the column, and sec-butyl acetate is extracted from the side stream. The bottom of the column is a mixture of C12 and sec-butyl acetate, which is discharged intermittently. (5) The bottom material of the azeotropic distillation column enters the deacetic acid tower. The acetic acid at the top of the deacetic acid tower is recycled back to the reaction system. The bottom material is deacidified by the C12 deacidification tank to obtain C12 product. The waste alkali liquid is sent out of the system.

6. The novel sec-butyl acetate production process according to claim 5, characterized in that, The operating conditions of the first-stage esterification reactor are: reaction temperature 70~90℃, reaction pressure 1.5~2.0MPa, acetic acid to butene molar ratio 1.1~2.0:1, and the resin catalyst used is D-005Ⅱ; The operating conditions of the two-stage esterification reactor are as follows: reaction temperature 80~100℃, reaction pressure 1.5~2.0MPa, total olefin molar ratio in acetic acid and C4 1.1~2.0:1, and the resin catalyst used is D-009.

7. The novel sec-butyl acetate production process according to claim 5, characterized in that, The operating conditions of the catalytic distillation column are as follows: top temperature 50~60℃, top pressure 0.5~0.6MPa, number of trays 50~70, feed inlet position 30~40, reflux ratio 1~3:1, 8~10 reaction sections are loaded, and the resin catalyst is D-005Ⅱ.

8. The novel sec-butyl acetate production process according to claim 1, characterized in that, The operating conditions of the C4 deacidification tower are as follows: top temperature 38~42℃, pressure 0.39~0.41MPa, water to C4 molar ratio 0.5~10:1, and number of trays 40~60. The operating conditions of the azeotropic distillation column are as follows: 60-90 trays, feed inlet position 20-30, top temperature 90-100℃, top pressure 0.02-0.07MPa, and reflux ratio 1-5.

9. The novel sec-butyl acetate production process according to claim 1, characterized in that, The operating conditions of the sec-butyl acetate product tower are as follows: 60-90 trays, 100-110℃ top temperature, 0.02-0.07MPa top pressure, 5-20 reflux ratio, and the position of the side stream outlet tray is 6-10.

10. The novel sec-butyl acetate production process according to claim 1, characterized in that, The operating conditions of the acetic acid removal tower are as follows: 20-30 trays, 10-15 feed inlet positions, 125-130℃ top temperature, 0.02-0.03MPa top pressure, and 0.5-2.0 reflux ratio.

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