Production device and preparation method of high-purity ethyl formate

Abstract

The invention discloses a preparation method of high-purity ethyl formate, which comprises the following steps: reaction synthesis: firstly adding a certain amount of formic acid into a reaction tank, adding excessive ethanol and a catalyst, and stirring the mixed solution to react; liquid separation: feeding the mixed liquid into a liquid separation tank for centrifugal separation, enabling an oil phase to enter a washing tank by utilizing a density difference, and breaking emulsification through an anti-emulsification assembly when emulsification occurs; washing and impurity removal: enabling the oil phase to enter a washing tank to be matched with washing liquid to neutralize the oil phase to obtain a neutralized oil phase and waste liquid, enabling the neutralized oil phase to enter a rectification tank, and enabling the waste liquid to flow into a washing barrel; rectifying and purifying: heating and gasifying the oil phase in a rectifying tank, heating, and collecting fractions to obtain ethyl formate; by means of the device, when the emulsification phenomenon occurs, the rotating sleeve drives the balancing weight to rotate to generate centrifugal force, it is ensured that an oil phase and a water phase are thoroughly separated, hindering of emulsification to the follow-up process is avoided, mixing of water and impurities in products is reduced, and the product quality is improved from the source.

Description

Technical Field

[0001] The invention relates to the technical field of ethyl formate production and manufacturing, in particular to a production device for high-purity ethyl formate and a preparation method thereof. Background Art

[0002] In the modern chemical industry, ethyl formate, as an important organic chemical raw material, is widely used in multiple key industries. In the food and spice industry, due to its unique and pleasant fruity aroma, it is often used as a blending ingredient in flavors and fragrances, giving various products an attractive fragrance. In the pharmaceutical field, it is an indispensable intermediate in the synthesis process of many drugs and plays a key role in promoting drug research and development and production. In the field of organic synthesis, ethyl formate has also become a basic raw material for the preparation of a variety of fine chemicals due to its special chemical properties.

[0003] However, in the process of producing ethyl formate by the esterification method, existing equipment will produce an emulsification phenomenon when separating the oil phase and the aqueous phase after the reaction is completed. Emulsification refers to the formation of a relatively stable mixture of two or more immiscible liquids under the dispersing effect of substances such as surfactants. In the production of ethyl formate, when unreacted catalysts (such as sulfuric acid), raw material impurities or reaction by-products are present in the reaction system, they may act as surfactants, reducing the interfacial tension between the oil phase (ethyl formate, ethanol, etc.) and the aqueous phase, promoting the formation of an emulsion, and hindering subsequent separation operations. Traditional gravity sedimentation or simple centrifugal separation methods are difficult to quickly and effectively break the emulsification system, resulting in a significant increase in separation time and reduced production efficiency. In addition, incomplete separation of the oil phase and the aqueous phase in the emulsified state will cause a large amount of water and impurities to be mixed into the ethyl formate product, seriously affecting the product purity.

[0004] Therefore, a production device and a preparation method of high-purity ethyl formate are proposed. Summary of the Invention

[0005] The object of the present invention is to provide a production device and a preparation method for high-purity ethyl formate, so as to solve the problem that gravity sedimentation or simple centrifugal separation methods proposed in the above background art are difficult to quickly and effectively break the emulsion system, resulting in a significant extension of the separation time and reduced production efficiency.

[0006] To achieve the above object, the present invention provides the following technical solution: a method for preparing high-purity ethyl formate, comprising the following steps:

[0007] S1. Reaction synthesis: a certain amount of formic acid is first added to a reaction tank, and then an excess of ethanol is slowly added, the molar ratio of ethanol to formic acid is 1.2:1-1.5:1, and concentrated sulfuric acid is added as a catalyst. The mixed solution is stirred and gradually heated to 65-70° C. under normal pressure and refluxed. Formic acid and ethanol undergo esterification reaction under the action of the catalyst to generate a mixed solution containing ethyl formate, unreacted raw materials, catalyst, water and by-products;

[0008] S2, liquid separation: A mixture containing ethyl formate, concentrated sulfuric acid, water, and a small amount of formic acid and ethanol is sent to a liquid separation tank for centrifugal separation. The oil phase enters the washing tank and the water phase is discharged by utilizing the density difference. If emulsification occurs, the emulsification prevention component is used to break the emulsification.

[0009] S3, washing and impurity removal: the oil phase enters the washing tank and is neutralized with the washing liquid to obtain the neutralized oil phase and waste liquid. The neutralized oil phase enters the distillation tank and the waste liquid flows into the washing barrel;

[0010] S4. Distillation purification: The oil phase is heated and vaporized in the distillation tank. After mass transfer through the filling layer, high-boiling-point impurities and part of ethanol and water vapor are condensed and refluxed. Ethyl formate vapor is condensed and discharged from the liquid outlet pipe. It is then heated to slowly raise the temperature of the liquid in the distillation tank to the boiling point of ethyl formate. The distillate is collected to obtain ethyl formate.

[0011] A production device for preparing high-purity ethyl formate, comprising an equipment support, a fixed base, a fixed frame, a rotating motor, a connecting flange, and a motor output rod, characterized in that it also comprises: a separation tank, a washing tank, and a distillation tank respectively mounted on the equipment support;

[0012] The liquid separating tank comprises a liquid separating shell, a feed valve is provided at the bottom of the liquid separating shell, a separation barrel is provided inside the liquid separating shell, a centrifugal assembly is fixedly connected to the separation barrel, a rising cover is movably connected inside the fixing frame, liquid outlet ports matching the centrifugal assembly are respectively provided on both sides of the liquid separating shell, an oil outlet is provided above the centrifugal assembly, a suction head is fixedly connected to the top of the fixing frame, the top of the liquid separating shell is sealed by a sealing plate, a connecting groove is provided on the rising cover, so that the mixed solution after the reaction enters the interior of the separation barrel through the feed valve, after centrifugal separation of the centrifugal assembly, the aqueous phase is thrown out from the liquid outlet, the oil phase overflows through the oil outlet, and accumulates upward until the rising cover is pushed upward, at this time, the connecting groove opened on the upper side of the rising cover coincides with the through hole on the suction head, and the oil phase is pumped to the upper layer for washing by a suction pump;

[0013] The separator is used to separate the oil phase and the water phase after the reaction, the washing tank is used to wash the impurities in the oil phase, and the distillation tank is used for distillation and purification to obtain high-purity ethyl formate.

[0014] Preferably: the liquid separation tank also includes an anti-emulsification component, the anti-emulsification component includes a rotating sleeve, and the rotating sleeve is fixedly connected to the motor output rod, the two ends of the rotating sleeve are fixedly connected to connecting rods, and the insides of the two connecting rods are fixedly connected to counterweights through springs, a limit seat is provided on the outside of the rotating sleeve, and the limit seat is fixedly connected to the rising cover, the inside of the rotating sleeve is fixedly connected to the limit buckle through a spring, a gear is rotatably connected to the side of the rotating sleeve, the inside of the gear is meshed with a large ratchet, the inside of the large ratchet is fixedly connected to the rotating shaft, and the Two small ratchets matching the rotating shaft are fixedly connected to the outer inner wall of the rotating sleeve, and torsion springs are respectively provided inside the large ratchets and the small ratchets. A tooth groove matching the gear is provided at the bottom of the counterweight block, so that when the connecting rod is thrown toward the limit seat by centrifugal force, the connecting rod is fixed in position under the meshing action of the gear and the large ratchet, thereby driving the rotating shaft to rotate. Conversely, when the centrifugal force decreases, the spring-loaded counterweight block shrinks inward, and at this time it is fixed in position under the meshing action of the rotating shaft and the small ratchet. At this time, the small ratchet drives the gear to rotate, thereby dropping the anti-emulsifier on both sides of the gear into the bottom.

[0015] Preferably: the washing tank includes a washing shell, a washing bucket is provided inside the washing shell, and a suction pump is fixedly connected to the bottom of the washing bucket, the suction pump is fixedly connected to the suction head, the washing shell is fixedly connected to an isolation plate, four oil phase outlets are fixedly connected to the suction pump through pipes on all four sides, and the four oil phase outlets are at the top of the washing shell so that the oil phase flows from top to bottom, a plurality of neutralization plates are provided above the isolation plate in the washing shell, and nozzles for spraying neutralized oil phase liquid are provided on the neutralization plates, so that the oil phase is sucked to the top of the washing shell by the suction pump, flows out from the oil phase outlet, and is mixed with the neutralization liquid sprayed from the nozzle through the staggered neutralization plates and washed.

[0016] Preferably: the distillation tank includes a distillation shell, a heating plate for distilling the oil phase is provided inside the distillation shell, a liquid outlet pipe is provided at the bottom of the distillation shell, and an oil pump for sucking out the oil phase inside the washing barrel is provided between the multiple liquid outlet pipes, a filling layer is fixedly connected to the inside of the distillation shell, and a condenser for condensation is provided at the top of the distillation shell.

[0017] Preferably: the rotating sleeve is welded to the motor output rod so that the motor output rod will not separate from the rotating sleeve during high-speed rotation. The connecting rod is a hollow rod structure, one end of which is fixedly connected to the rotating sleeve, and the other end is detachably connected to the counterweight block by bolts, which is convenient for replacement and maintenance of the counterweight block. The counterweight block has a smooth surface, and the counterweight block matches the hollow groove inside the connecting rod to prevent it from getting stuck due to friction during rotation. The limit seat is fixedly installed on the upper end of the rising cover.

[0018] Preferably: the washing shell is a cylindrical sealing structure, and the washing shell is made of corrosion-resistant stainless steel to prevent material residue and corrosion, the suction pump is a centrifugal pump, and the impeller adopts a closed impeller to improve the suction efficiency and reliability, the isolation plate is a horizontally arranged flat plate structure, the oil phase outlet is a circular hole, and the oil phase outlets are evenly distributed on the top of the washing shell to ensure that the oil phase flows evenly into multiple neutralization plates, the neutralization plate is an inclined plate structure with a certain slope, and a guide groove is provided on the surface for guiding the washing liquid to be evenly distributed on the neutralization plate, the nozzle is an atomizing nozzle to ensure that the washing liquid can fully cover the oil phase, the washing barrel is a conical structure, and a discharge valve for controlling the waste liquid after washing is installed on the drain port.

[0019] Preferably: the distillation shell is a cylindrical tower structure, and the outside of the distillation shell is provided with an insulation layer for reducing heat loss, the heating plate is an electric heating plate, the liquid outlet pipe is a stainless steel pipe, and a flow regulating valve is installed on the liquid outlet pipe for adjusting the discharge flow of the product after distillation, the filling layer adopts stainless steel wire mesh corrugated filler, the condenser is a shell and tube condenser, and the cooling water inlet and outlet are respectively provided with a temperature sensor and a flow regulating valve for accurately controlling the condensation temperature and cooling water volume.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. The present invention uses the high-speed operation of the centrifugal assembly in the separator tank to rapidly separate the oil phase and the water phase based on their density difference by centrifugal force, greatly shortening the time required for separation and thereby improving production efficiency. When emulsification occurs, the rotating sleeve drives the counterweight block to rotate at high speed. The generated centrifugal force cooperates with the meshing structure of the gear and ratchet to release the demulsifier. This dual action can effectively destroy the emulsification system and ensure the complete separation of the oil phase and the water phase. This not only avoids the obstruction of emulsification to subsequent processes, but also reduces the mixing of water and impurities in the product, thereby improving product quality from the source.

[0022] 2. The present invention uses a suction pump in the washing tank to evenly spray the washing liquid through the atomizing nozzle. The atomized washing liquid can fully contact the oil phase from the separator tank. The washing liquid can dissolve or neutralize impurities in the oil phase, such as residual acidic catalysts and raw material impurities. The neutralization plate is designed as an inclined plate structure with a certain slope and a guide groove on the surface. This design allows the washing liquid to be evenly distributed on the neutralization plate, further enhancing the washing effect. The washing bucket is used to collect the waste liquid after washing, which is convenient for centralized treatment. After treatment in the washing tank, the impurities in the oil phase are greatly reduced, providing purer raw materials for subsequent distillation and purification, helping to improve the purity of the final product ethyl formate, and meeting the strict requirements of industrial production for high-purity products.

[0023] 3. The present invention stably heats the incoming oil phase through the heating plate in the distillation tank, so that it is smoothly vaporized. The steam fully carries out a mass transfer process with the reflux liquid in the filling layer. The stainless steel wire mesh corrugated packing used in the filling layer has a large specific surface area, which creates good conditions for the separation of various components in the steam. In this process, high-boiling point impurities and part of the ethanol and water vapor in the steam will be condensed when cooled and then reflux to the bottom of the distillation shell. Due to its low boiling point, the ethyl formate vapor will continue to rise to the condenser. The condenser accurately controls the cooling water volume and temperature to accurately condense the ethyl formate vapor into a liquid state. The flow regulating valve on the liquid outlet pipe can accurately control the discharge flow rate. The entire distillation process efficiently removes residual impurities, and finally obtains a high-purity ethyl formate product, thereby improving the market competitiveness of the product and meeting the stringent requirements of the food, medicine, organic synthesis and other industries for high-purity ethyl formate. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a flow chart of the method of the present invention;

[0025] Figure 2 It is a schematic diagram of the overall structure of the present invention;

[0026] Figure 3 It is a sectional perspective view of the overall structure of the present invention;

[0027] Figure 4 It is a cross-sectional view of the overall structure of the present invention;

[0028] Figure 5 This is an exploded view of the washing tank of the present invention;

[0029] Figure 6 It is an exploded view of the distillation tank of the present invention;

[0030] Figure 7 This is an exploded view of the liquid separator of the present invention;

[0031] Figure 8 It is a cross-sectional view of the liquid separation tank of the present invention;

[0032] Figure 9 is a cross-sectional view of the anti-emulsification component of the present invention;

[0033] Figure 10 This is a disassembled diagram of the anti-emulsification component of the present invention.

[0034] In the picture:

[0035] 1. Equipment bracket; 2. Fixed base; 3. Fixed frame;

[0036] 4. Separator tank; 41. Separator housing; 42. Feed valve; 43. Separator barrel; 44. Centrifugal assembly; 45. Rising cover; 46. Liquid outlet; 47. Oil outlet; 48. Suction head; 49. Sealing plate; 410. Connecting groove;

[0037] 411. Anti-emulsification assembly; 4111. Rotating sleeve; 4112. Connecting rod; 4113. Counterweight; 4114. Limit seat; 4115. Limit buckle; 4116. Gear; 4117. Large ratchet; 4118. Rotating shaft; 4119. Small ratchet;

[0038] 5. Washing tank; 51. Washing shell; 52. Suction pump; 53. Isolation plate; 54. Oil phase outlet; 55. Neutralization plate; 56. Spray nozzle; 57. Washing bucket;

[0039] 6. Distillation tank; 61. Distillation shell; 62. Heating plate; 63. Liquid outlet pipe; 64. Filling layer; 65. Condenser;

[0040] 7. Rotating motor; 8. Connecting flange; 9. Motor output rod. DETAILED DESCRIPTION

[0041] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0042] See also Figures 1 to 10 The present invention provides a method for preparing high-purity ethyl formate, comprising the following steps:

[0043] S1. Reaction synthesis: a certain amount of formic acid is first added to a reaction tank, and then an excess of ethanol is slowly added, the molar ratio of ethanol to formic acid is 1.2:1-1.5:1, and concentrated sulfuric acid is added as a catalyst. The mixed solution is stirred and gradually heated to 65-70° C. under normal pressure and refluxed. Formic acid and ethanol undergo esterification reaction under the action of the catalyst to generate a mixed solution containing ethyl formate, unreacted raw materials, catalyst, water and by-products;

[0044] S2, liquid separation: A mixture containing ethyl formate, concentrated sulfuric acid, water, and a small amount of formic acid and ethanol is sent to a liquid separation tank for centrifugal separation. The oil phase enters the washing tank and the water phase is discharged by utilizing the density difference. If emulsification occurs, the emulsification prevention component is used to break the emulsification.

[0045] S3, washing and impurity removal: the oil phase enters the washing tank and is neutralized with the washing liquid to obtain the neutralized oil phase and waste liquid. The neutralized oil phase enters the distillation tank and the waste liquid flows into the washing barrel;

[0046] S4. Distillation purification: The oil phase is heated and vaporized in the distillation tank. After mass transfer through the filling layer, high-boiling-point impurities and part of ethanol and water vapor are condensed and refluxed. Ethyl formate vapor is condensed and discharged from the liquid outlet pipe. It is then heated to slowly raise the temperature of the liquid in the distillation tank to the boiling point of ethyl formate. The distillate is collected to obtain ethyl formate.

[0047] See Figures 2 to 10 The present invention provides a production device for a method of preparing high-purity ethyl formate, comprising an equipment support 1, a fixed base 2, a fixed frame 3, a rotating motor 7, a connecting flange 8, and a motor output rod 9, characterized in that it also comprises: a separating tank 4, a washing tank 5, and a distillation tank 6, respectively mounted on the equipment support 1;

[0048] The liquid separation tank 4 includes a liquid separation shell 41, a feed valve 42 is provided at the bottom of the liquid separation shell 41, a separation barrel 43 is provided inside the liquid separation shell 41, a centrifugal assembly 44 is fixedly connected to the separation barrel 43, and a rising cover 45 is movably connected inside the fixed frame 3. Liquid outlets 46 matching the centrifugal assembly 44 are respectively provided on both sides of the liquid separation shell 41, an oil outlet 47 is provided above the centrifugal assembly 44, a suction head 48 is fixedly connected to the top of the fixed frame 3, the top of the liquid separation shell 41 is sealed by a sealing plate 49, and a connecting groove 410 is provided on the rising cover 45 to allow the reacted mixed solution to enter the interior of the separation barrel 43 through the feed valve 42. After centrifugal separation by the centrifugal assembly 44, the aqueous phase is thrown out from the liquid outlet 46, and the oil phase overflows through the oil outlet 47 and accumulates upward until the rising cover 45 is pushed upward. At this time, the connecting groove 410 opened on the upper side of the rising cover 45 coincides with the through hole on the suction head 48, and the oil phase is pumped to the upper layer for washing by the suction pump 52;

[0049] The separator 4 is used to separate the oil phase and the water phase after the reaction, the washing tank 5 is used to wash the impurities in the oil phase, and the distillation tank 6 is used for distillation and purification to obtain high-purity ethyl formate.

[0050] During operation, the mixed liquid after the reaction is completed flows into the separation barrel 43 through the feed valve 42, and the centrifugal component 44 is started. Under the action of centrifugal force, due to the different densities of the oil phase and the water phase, the water phase is affected by the centrifugal force and is thrown out of the separation barrel 43 from the liquid outlet 46. The oil phase, due to its smaller density, will overflow through the oil outlet 47 and accumulate upward in the separation barrel 43. As the oil phase continues to accumulate, the rising cover 45 will be pushed upward. When the rising cover 45 rises to a certain position, the connecting groove 410 above it will coincide with the through hole on the suction head 48. At this time, the oil phase will be pumped to the upper washing tank 5 through the connecting groove 410 and the suction head 48 under the action of the suction pump 52, and enter the subsequent washing process.

[0051] As an embodiment of the present invention, Figure 2 、 3 、 Figure 7 、 Figure 8 、 Figure 9 and Figure 10 As shown, the liquid separator 4 also includes an anti-emulsification component 411, which includes a rotating sleeve 4111, and the rotating sleeve 4111 is fixedly connected to the motor output rod 9, and the two ends of the rotating sleeve 4111 are fixedly connected to connecting rods 4112, and the insides of the two connecting rods 4112 are fixedly connected to counterweight blocks 4113 through springs, and a limiting seat 4114 is provided on the outside of the rotating sleeve 4111, and the limiting seat 4114 is fixedly connected to the rising cover 45, and the inside of the rotating sleeve 4111 is fixedly connected to the limiting buckle 4115 through a spring, and a gear 4116 is rotatably connected to the side of the rotating sleeve 4111, and the inside of the gear 4116 is engaged with the large ratchet 4117, and the inside of the large ratchet 4117 is fixedly connected to the rotating shaft 4118, and the rotating sleeve 4111 is fixedly connected to the rotating shaft 4118. Two small ratchets 4119 matching the rotating shaft 4118 are fixedly connected to the inner wall of the outer side, and a torsion spring is provided inside the large ratchet 4117 and the small ratchet 4119 respectively. A tooth groove matching the gear 4116 is provided at the bottom of the counterweight 4113, so that when the connecting rod 4112 is thrown toward the limit seat 4114 by centrifugal force, the connecting rod 4112 is fixed in place under the meshing action of the gear 4116 and the large ratchet 4117, thereby driving the rotating shaft 4118 to rotate. Conversely, when the centrifugal force decreases, the spring-loaded counterweight 4113 contracts inwardly. At this time, it is fixed in place under the meshing action of the rotating shaft 4118 and the small ratchet 4119. At this time, the small ratchet 4119 drives the gear 4116 to rotate, thereby dropping the anti-emulsifier on both sides of the gear 4116 into the bottom;

[0052] The rotating sleeve 4111 is welded to the motor output rod 9 so that the motor output rod 9 will not separate from the rotating sleeve 4111 during high-speed rotation. The connecting rod 4112 is a hollow rod structure, one end of which is fixedly connected to the rotating sleeve 4111, and the other end is detachably connected to the counterweight block 4113 by bolts, which is convenient for replacement and maintenance of the counterweight block 4113. The counterweight block 4113 has a smooth surface, and the counterweight block 4113 matches the hollow groove inside the connecting rod 4112 to prevent it from getting stuck due to friction during rotation. The limit seat 4114 is fixedly installed on the upper end of the rising cover 45.

[0053] During operation, if emulsification occurs during the separation process, the motor output rod 9 drives the rotating sleeve 4111 to rotate at a high speed. The counterweights 4113 in the connecting rods 4112 at both ends of the rotating sleeve 4111 are thrown out toward the limit seat 4114 along the connecting rods 4112 due to the centrifugal force. In this process, the tooth grooves at the bottom of the counterweights 4113 mesh with the gears 4116, and the meshing transmission between the gears 4116 and the large ratchet 4117 drives the rotating shaft 4118 to rotate. When the centrifugal force decreases, the spring in the connecting rod 4112 pulls the counterweights 4113 inward and contracts. At this time, the rotating shaft 4118 and the small ratchet 41 19 mesh with each other, and the small ratchet 4119 drives the gear 4116 to rotate, so that the anti-emulsifier stored on both sides of the gear 4116 is dropped into the bottom of the separation barrel 43. In this process, the anti-emulsifier can be a polyether demulsifier, which mainly demulsifies by changing the properties of the interfacial film. The lipophilic group is adsorbed on the surface of the oil droplet, and the hydrophilic group extends to the water phase, replacing the original emulsifier. After demulsification, the residual demulsifier component is easy to separate in the subsequent distillation process due to the large difference in boiling point with ethyl formate, so that too many impurities will not be introduced, thereby ensuring product purity, destroying the emulsified state, and ensuring that the oil phase and the water phase can be separated smoothly.

[0054] In one embodiment of the present invention, Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 and Figure 6 As shown: the washing tank 5 includes a washing shell 51, a washing bucket 57 is provided inside the washing shell 51, and a suction pump 52 is fixedly connected to the bottom of the washing bucket 57, and the suction pump 52 is fixedly connected to the suction head 48. The washing shell 51 is fixedly connected to an isolation plate 53. Four oil phase outlets 54 are fixedly connected to the suction pump 52 through pipes on all sides, and the four oil phase outlets 54 are located at the top of the washing shell 51 so that the oil phase flows from top to bottom. A plurality of neutralization plates 55 are provided above the isolation plate 53 in the washing shell 51, and each neutralization plate 55 is provided with a nozzle 56 for spraying a neutralizing oil phase liquid, so that the oil phase is sucked to the top of the washing shell 51 by the suction pump 52, flows out from the oil phase outlet 54, and is mixed with the neutralization liquid sprayed from the nozzle 56 through the staggered neutralization plates 55 for washing;

[0055] The washing shell 51 is a cylindrical sealed structure, and the material of the washing shell 51 is corrosion-resistant stainless steel to prevent material residue and corrosion. The suction pump 52 is a centrifugal pump, and the impeller adopts a closed impeller to improve the suction efficiency and reliability. The isolation plate 53 is a horizontally arranged flat plate structure, and the oil phase outlet 54 is a circular hole, and the oil phase outlet 54 is evenly distributed on the top of the washing shell 51 to ensure that the oil phase flows evenly into multiple neutralization plates 55. The neutralization plate 55 is an inclined plate structure with a certain slope, and a guide groove is provided on the surface to guide the washing liquid to be evenly distributed on the neutralization plate 55. The nozzle 56 is an atomizing nozzle to ensure that the washing liquid can fully cover the oil phase. The washing barrel 57 is a conical structure, and a discharge valve for controlling the waste liquid after washing is installed on the drain port.

[0056] During operation, the oil phase flowing out of the oil outlet 47 of the liquid separator 4 enters the upper part of the neutralization plate 55 through the oil phase outlet 54 on the isolation plate 53. The suction pump 52 fixedly connected to the bottom of the washing barrel 57 is started to spray the washing liquid through the nozzle 56. The nozzle 56 is an atomizing nozzle, which can spray the washing liquid in the form of mist to fully cover the oil phase flowing down from above. The oil phase flows from top to bottom under the action of gravity and fully contacts and mixes with the neutralization liquid sprayed from the nozzle 56 on the staggered neutralization plates 55. The neutralization plate 55 is an inclined plate structure with a certain slope. The guide groove arranged on its surface can guide the washing liquid to be evenly distributed on the neutralization plate 55. (The washing liquid adopts saturated sodium bicarbonate solution. , the acidic impurities in ethyl formate can be converted into sodium formate, water and carbon dioxide. The carbon dioxide escapes in the form of gas and leaves the reaction system without introducing new impurities. Sodium formate is easily soluble in water and will be separated with the water phase in the subsequent liquid separation operation, thereby achieving the purpose of removing acidic impurities). The washing effect is further enhanced, so that the washing liquid can more fully dissolve or neutralize the impurities in the oil phase, such as residual acidic catalyst, raw material impurities, etc. The oil phase after washing will enter the distillation tank 6 for the next step of treatment, and the waste liquid generated during the washing process will flow into the washing barrel 57. By controlling the valve of the liquid discharge port of the washing barrel 57, the discharge operation of the waste liquid after washing can be achieved.

[0057] As an embodiment of the present invention, Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 and Figure 6 As shown, the distillation tank 6 includes a distillation shell 61, a heating plate 62 for distilling the oil phase is provided in the distillation shell 61, a liquid outlet pipe 63 is provided at the bottom of the distillation shell 61, and an oil pump for sucking out the oil phase inside the washing barrel 57 is provided between the multiple liquid outlet pipes 63. A filling layer 64 is fixedly connected to the interior of the distillation shell 61, and a condenser 65 for condensation is provided at the top of the distillation shell 61;

[0058] The distillation shell 61 is a cylindrical tower structure, and the outside of the distillation shell 61 is provided with an insulation layer for reducing heat loss. The heating plate 62 is an electric heating plate, the liquid outlet pipe 63 is a stainless steel pipe, and a flow regulating valve is installed on the liquid outlet pipe 63 for adjusting the discharge flow of the product after distillation. The filling layer 64 adopts stainless steel wire mesh corrugated filler, the condenser 65 is a shell and tube condenser, and the cooling water inlet and outlet are respectively provided with a temperature sensor and a flow regulating valve for accurately controlling the condensation temperature and cooling water volume.

[0059] During operation, the oil phase coming from the washing tank 5 is pumped into the distillation shell 61 by the action of the oil pump between the multiple liquid outlet pipes 63. The heating plate 62 in the distillation shell 61 starts to work to heat the oil phase. The oil phase is heated and vaporized to produce steam. The steam moves upward through the filling layer 64. The filling layer 64 uses stainless steel wire mesh corrugated packing. This packing has a large specific surface area and can provide good mass transfer conditions for the separation of various components in the steam. In the filling layer 64, high-boiling-point impurities and part of ethanol and water vapor in the steam will be condensed when cooled, and then flow back to the bottom of the distillation shell 61, while the ethyl formate vapor will condense due to its boiling point. The temperature of the ethyl formate vapor is relatively low and will continue to rise to reach the condenser 65. The condenser 65 is a shell-and-tube condenser. The temperature sensors and flow regulating valves arranged at the cooling water inlet and outlet can accurately control the condensation temperature and the amount of cooling water. Under appropriate condensation conditions, the ethyl formate vapor is condensed into liquid and finally discharged from the liquid outlet pipe 63. The operator can accurately control the discharge flow of the distilled product by adjusting the flow regulating valve on the liquid outlet pipe 63, thereby obtaining a high-purity ethyl formate product that meets the purity requirements. The overall efficient and continuous production is realized, meeting the demand for high-purity ethyl formate in the food, medicine, organic synthesis and other industries.

[0060] Working principle: Formic acid and ethanol undergo esterification reaction in the reaction vessel under the action of a catalyst to generate a mixed liquid containing ethyl formate, unreacted raw materials, catalyst, water and reaction by-products. The mixed liquid enters the separation barrel 43 of the liquid separator 4 through the feed valve 42, and the centrifugal component 44 is started. The density difference between the oil phase and the water phase is used to throw the water phase out from the liquid outlet 46, and the oil phase overflows from the oil outlet 47 and pushes the rising cover 45. When the connecting groove 410 of the rising cover 45 is connected to the suction head When the through holes 48 overlap, the oil phase is pumped into the washing tank 5 by the suction pump 52. If emulsification occurs during separation, the motor output rod 9 drives the rotating sleeve 4111 to rotate. Under the action of centrifugal force, the counterweight 4113 is thrown along the connecting rod 4112 to the limit seat 4114, and the gear 4116 and the large ratchet 4117 drive the rotating shaft 4118 to rotate. When the centrifugal force decreases, the counterweight 4113 contracts, and the small ratchet 4119 drives the gear 4116 to rotate, and the anti-emulsification agent is removed. The oil phase is put into the bottom of the separation barrel 43 to destroy the emulsification system. In the washing tank 5, the oil phase enters the upper part of the neutralization plate 55 through the oil phase outlet 54 of the isolation plate 53. The suction pump 52 sprays the washing liquid through the atomizing nozzle 56, and it fully contacts the oil phase on the staggered neutralization plates 55. The inclined structure and guide grooves of the neutralization plates 55 ensure that the washing liquid is evenly distributed, dissolving or neutralizing impurities. The washed oil phase enters the distillation tank 6, and the waste liquid flows into the washing barrel 57 and is discharged by the drain valve. In the distillation tank 6, the oil phase is pumped into the distillation shell 61 by the oil pump. The heating plate 62 heats it to vaporize it. The vapor passes through the stainless steel wire mesh corrugated packing layer 64, and the high-boiling point impurities and part of the ethanol and water vapor are condensed and refluxed. The ethyl formate vapor rises to the condenser 65, and the cooling temperature and water volume are precisely controlled by the temperature sensor and the flow control valve to condense it. Finally, it is discharged through the liquid outlet pipe 63. The flow control valve can be adjusted to control the discharge flow rate to obtain high-purity ethyl formate product.

[0061] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing high-purity ethyl formate, characterized in that: The following steps are involved: S1. Reaction synthesis: a certain amount of formic acid is first added to a reaction tank, and then an excess of ethanol is slowly added, the molar ratio of ethanol to formic acid is 1.2:1-1.5:1, and concentrated sulfuric acid is added as a catalyst. The mixed solution is stirred and gradually heated to 65-70° C. under normal pressure and refluxed. Formic acid and ethanol undergo esterification reaction under the action of the catalyst to generate a mixed solution containing ethyl formate, unreacted raw materials, catalyst, water and by-products; S2, liquid separation: A mixture containing ethyl formate, concentrated sulfuric acid, water, and a small amount of formic acid and ethanol is sent to a liquid separation tank for centrifugal separation. The oil phase enters the washing tank and the water phase is discharged by utilizing the density difference. If emulsification occurs, the emulsification prevention component is used to break the emulsification. S3, washing and impurity removal: the oil phase enters the washing tank and is neutralized with the washing liquid to obtain the neutralized oil phase and waste liquid. The neutralized oil phase enters the distillation tank and the waste liquid flows into the washing barrel; S4. Distillation purification: The oil phase is heated and vaporized in the distillation tank. After mass transfer through the filling layer, high-boiling-point impurities and part of ethanol and water vapor are condensed and refluxed. Ethyl formate vapor is condensed and discharged from the liquid outlet pipe. It is then heated to slowly raise the temperature of the liquid in the distillation tank to the boiling point of ethyl formate. The distillate is collected to obtain ethyl formate.

2. The production device of the method for preparing high-purity ethyl formate according to claim 1, comprising an equipment support (1), a fixed base (2), a fixed frame (3), a rotating motor (7), a connecting flange (8) and a motor output rod (9), characterized in that: Also includes: A liquid separation tank (4), a washing tank (5) and a distillation tank (6) are respectively mounted on the equipment support (1); The liquid separation tank (4) comprises a liquid separation shell (41), a feed valve (42) is provided at the bottom of the liquid separation shell (41), a separation barrel (43) is provided inside the liquid separation shell (41), a centrifugal assembly (44) is fixedly connected inside the separation barrel (43), a rising cover (45) is movably connected inside the fixed frame (3), liquid outlets (46) matching the centrifugal assembly (44) are respectively provided on both sides of the liquid separation shell (41), an oil outlet (47) is provided above the centrifugal assembly (44), and a suction head (48) is fixedly connected to the top of the fixed frame (3). The top of the liquid separation housing (41) is sealed by a sealing plate (49), and a connecting groove (410) is provided on the rising cover (45) so that the mixed solution after the reaction enters the interior of the separation barrel (43) through the feed valve (42). After centrifugal separation by the centrifugal assembly (44), the water phase is thrown out from the liquid outlet (46), and the oil phase overflows through the oil outlet (47) and accumulates upward until the rising cover (45) is pushed upward. At this time, the connecting groove (410) opened on the upper side of the rising cover (45) coincides with the through hole on the suction head (48), and the oil phase is pumped to the upper layer for washing by the suction pump (52); The liquid separation tank (4) is used to separate the oil phase and the water phase after the reaction, the washing tank (5) is used to wash impurities in the oil phase, and the distillation tank (6) is used for distillation and purification to obtain high-purity ethyl formate.

3. The production device according to claim 2, characterized in that: The liquid separation tank (4) further comprises an anti-emulsification component (411), the anti-emulsification component (411) comprising a rotating sleeve (4111), and the rotating sleeve (4111) is fixedly connected to the motor output rod (9), the two ends of the rotating sleeve (4111) are fixedly connected to connecting rods (4112), and the interiors of the two connecting rods (4112) are fixedly connected to counterweights (4113) via springs, a limiting seat (4114) is provided on the outside of the rotating sleeve (4111), and the limiting seat (4114) is fixedly connected to the rising cover (45), the interior of the rotating sleeve (4111) is fixedly connected to a limiting buckle (4115) via a spring, a gear (4116) is rotatably connected to the side of the rotating sleeve (4111), the interior of the gear (4116) is meshed with a large ratchet (4117), and the interior of the large ratchet (4117) is fixedly connected to a rotating shaft (4118), Two small ratchets (4119) matching the rotating shaft (4118) are fixedly connected to the inner wall of the outer side of the rotating sleeve (4111), and the inside of the large ratchets (4117) and the small ratchets (4119) are respectively provided with torsion springs. The bottom of the counterweight (4113) is provided with a tooth groove matching the gear (4116), so that when the connecting rod (4112) is thrown toward the limit seat (4114) by centrifugal force, the connecting rod (4112) ) is fixed in position under the meshing action of the gear (4116) and the large ratchet (4117), thereby driving the rotating shaft (4118) to rotate. Conversely, when the centrifugal force decreases, the spring-loaded counterweight (4113) contracts inward. At this time, it is fixed in position under the meshing action of the rotating shaft (4118) and the small ratchet (4119). At this time, the small ratchet (4119) drives the gear (4116) to rotate, thereby dropping the anti-emulsifier on both sides of the gear (4116) into the bottom.

4. The production device according to claim 2, characterized in that: The washing tank (5) comprises a washing shell (51), a washing bucket (57) is provided inside the washing shell (51), and a suction pump (52) is fixedly connected to the bottom of the washing bucket (57), the suction pump (52) is fixedly connected to the suction head (48), the washing shell (51) is fixedly connected to an isolation plate (53), and four oil phase outlets (54) are fixedly connected to the four sides of the suction pump (52) through pipelines, and the four oil phase outlets (54) are in the washing The top of the washing shell (51) is provided with a plurality of neutralizing plates (55) above the isolation plate (53) in the washing shell (51), and each of the neutralizing plates (55) is provided with a nozzle (56) for spraying a liquid for neutralizing the oil phase, so that the oil phase is sucked to the top of the washing shell (51) by the suction pump (52), flows out from the oil phase outlet (54), and is mixed with the neutralizing liquid sprayed from the nozzle (56) through the staggered neutralizing plates (55) for washing.

5. The production device according to claim 2, characterized in that: The distillation tank (6) comprises a distillation shell (61), a heating plate (62) for distilling the oil phase is provided in the distillation shell (61), a liquid outlet pipe (63) is provided at the bottom of the distillation shell (61), and an oil pump for sucking out the oil phase inside the washing bucket (57) is provided between the plurality of liquid outlet pipes (63), a filling layer (64) is fixedly connected to the inside of the distillation shell (61), and a condenser (65) for condensation is provided at the top of the distillation shell (61).

6. The production device according to claim 3, characterized in that: The rotating sleeve (4111) is welded to the motor output rod (9) so that the motor output rod (9) will not be separated from the rotating sleeve (4111) during high-speed rotation. The connecting rod (4112) is a hollow rod structure, one end of which is fixedly connected to the rotating sleeve (4111) and the other end is detachably connected to the counterweight (4113) by bolts, which facilitates the replacement and maintenance of the counterweight (4113). The counterweight (4113) has a smooth surface and matches the hollow groove inside the connecting rod (4112) to prevent it from being stuck due to friction during rotation. The limit seat (4114) is fixedly installed on the upper end of the rising cover (45).

7. The production device according to claim 4, characterized in that: The washing shell (51) is a cylindrical sealing structure, and the material of the washing shell (51) is corrosion-resistant stainless steel to prevent material residue and corrosion. The suction pump (52) is a centrifugal pump, and the impeller adopts a closed impeller to improve the suction efficiency and reliability. The isolation plate (53) is a horizontally arranged flat plate structure. The oil phase outlet (54) is a circular hole, and the oil phase outlet (54) is evenly distributed on the top of the washing shell (51) to ensure that the oil phase flows evenly into multiple neutralization plates (55). The neutralization plate (55) is an inclined plate structure with a certain slope, and a guide groove is provided on the surface to guide the washing liquid to be evenly distributed on the neutralization plate (55). The nozzle (56) is an atomizing nozzle to ensure that the washing liquid can fully cover the oil phase. The washing bucket (57) is a conical structure, and a discharge valve for controlling the discharge of waste liquid after washing is installed on the discharge port.

8. The production device according to claim 5, characterized in that: The distillation shell (61) is a cylindrical tower structure, and the outside of the distillation shell (61) is provided with an insulation layer for reducing heat loss, the heating plate (62) is an electric heating plate, the liquid outlet pipe (63) is a stainless steel pipe, and a flow regulating valve is installed on the liquid outlet pipe (63) for regulating the discharge flow of the distilled product, the filling layer (64) adopts stainless steel wire mesh corrugated filler, the condenser (65) is a shell and tube condenser, and the cooling water inlet and outlet are respectively provided with a temperature sensor and a flow regulating valve for accurately controlling the condensation temperature and the cooling water amount.

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