Purification method and purification equipment of piperidine and product

Abstract

The invention provides a piperidine purification method, purification equipment and a product, and the method comprises the following steps: carrying out gas-liquid separation on a piperidine crude product containing bio-based pentamethylene diamine, bio-based piperidine, water and ammonia gas to obtain a gas phase and a liquid phase; the liquid phase is subjected to distillation treatment according to the following mode (a) or (b): (a) the liquid phase is subjected to first distillation to remove light components, collected feed liquid is subjected to second distillation to remove heavy components, distillate is condensed, and a purified piperidine product is obtained; and (b) carrying out first distillation on the liquid phase to remove heavy components, carrying out second distillation on the distilled fraction to remove light components, and collecting the feed liquid which is a purified piperidine product. The purification process provided by the invention is simple in process flow, and the obtained product is high in purity, low in pentamethylene diamine impurity content, low in platinum-cobalt color number, low in water content and almost free of pyridine impurities, and can be widely applied to the fields of rubber accelerators, pesticides, medicines and the like.

Description

Technical Field

[0001] The invention relates to the technical field of separation and purification of chemical products, and in particular to a piperidine purification method, purification equipment and product. Background Art

[0002] Piperidine (molecular formula: (CH2)5NH, CAS No. 110-89-4), also known as hexahydropyridine, is a cyclic aliphatic secondary amine and a medium-strong base. It is a colorless fuming liquid at room temperature with a pungent odor similar to ammonia and pepper. As a very important fine chemical intermediate, piperidine has a wide range of uses and has been developed and applied in areas such as pharmaceutical synthesis, agricultural chemical synthesis, and rubber product synthesis. In recent years, with the expansion of piperidine's application fields, especially the emergence of a large number of new drugs containing piperidine structures, the demand for high-purity piperidine has greatly increased, and its application prospects are broad.

[0003] There are some reports on the method of preparing piperidine by catalytic deamination with pentamethylenediamine as raw material under the action of catalyst. For example, U.S. Patent No. 2863872 uses silica gel, silica-alumina gel, etc. as catalyst to prepare piperidine by gas-solid phase reaction in a fixed bed reactor, the reaction temperature is 300-500° C., and the reaction materials are condensed and distilled to obtain the product piperidine; American scholars reported that pentamethylenediamine is used as raw material in diphenyl ether organic solvent, in the presence of 2% (molar percentage) triphenylphosphine ruthenium chloride catalyst to prepare piperidine, the reaction temperature is 180° C., and the reaction time is 5 hours (JOC, 1981, 46, 1759-1760); Japanese scholars found that in water phase, using precious metal Ru / C supported on carbon and aluminum powder as catalysts, piperidine can be synthesized from pentamethylenediamine with a high yield (Tetrahedron, 2000, 66, 1249-1253); Chinese Patent CN 104844539 A discloses a process for converting bio-based 1,5-pentanediamine into piperidine, and piperidine is prepared in the presence of a modified molecular sieve catalyst.

[0004] Although some reports mentioned the use of various catalysts to produce piperidine, there is currently no factory that actually uses pentamethylenediamine to produce piperidine, and there is no report on related equipment and processes for separation and purification of piperidine. In addition, when piperidine is prepared from 1,5-pentamethylenediamine as a raw material, a small amount of 1,5-pentamethylenediamine, ammonia, and water residues still exist in the crude piperidine product. In order to further improve the quality of the piperidine product, they need to be further removed through a purification process and system. Summary of the invention

[0005] In order to solve the above problems existing in the prior art, the present invention provides a piperidine purification method, purification equipment and product. The method can extract a high-purity bio-based piperidine product, and the piperidine product contains almost no pyridine, has low pentamethylenediamine content, low water content, and low platinum-cobalt color number, and has broad application prospects; and the waste gas resources generated in the reaction process can be efficiently recycled.

[0006] The present invention provides a method for purifying piperidine, comprising:

[0007] performing gas-liquid separation on a crude piperidine product containing bio-based pentamethylenediamine, bio-based piperidine, water and ammonia to obtain a gas phase and a liquid phase;

[0008] The liquid phase is distilled in the following manner (a) or (b):

[0009] (a) liquid phase is subjected to a first distillation to remove light constituents, the collected feed liquid is subjected to a second distillation to remove heavy constituents, and the distillate is condensed to obtain the purifying piperidine product;

[0010] (b) subjecting the liquid phase to a first distillation to remove heavy components, subjecting the distilled fraction to a second distillation to remove light components, and collecting the feed liquid to be the purified piperidine product.

[0011] The present invention also provides a piperidine purification device, comprising:

[0012] A separation device, used for performing gas-liquid separation on the crude piperidine product to obtain a gas phase and a liquid phase;

[0013] a first distillation device, for distilling the liquid phase to remove light components / heavy components;

[0014] a second distillation device, for distilling the collected feed liquid / distilled fraction to remove heavy components / light components to obtain a distillate / purified piperidine product; and

[0015] An optional condensation device is used to condense the distillate to obtain a purified piperidine product.

[0016] The present invention further provides a method for purifying piperidine, which adopts the above-mentioned purification equipment.

[0017] The present invention further provides a piperidine product extracted by the above purification method, wherein the piperidine product is 100% bio-based, and the piperidine purity is ≥99.5%, further ≥99.7%; and / or,

[0018] The content of pentamethylenediamine in the piperidine product is ≤100ppm; and / or,

[0019] The pyridine content in the piperidine product is ≤1000ppm, further ≤100ppm, further ≤10ppm; and / or,

[0020] The water content of the piperidine product is ≤0.2%, further ≤0.1%; and / or,

[0021] The platinum-cobalt color number of the piperidine product is ≤8; and / or,

[0022] The piperidine product has a density of 0.86-0.865 g / L.

[0023] The positive and progressive effects of the present invention are:

[0024] The purification process provided by the present invention has a simple process flow, a high purity of the obtained product, a low content of pentamethylenediamine impurities, a low platinum-cobalt color number, a low water content, and almost no pyridine impurities, and can be widely used in the fields of rubber accelerators, pesticides, medicines, etc. The purification equipment provided by the present invention has a simple structure, a small footprint, and is easy to operate.

[0025] In addition, the present invention can solve the environmental pollution caused by the waste gas by effectively recycling the waste gas obtained by separating the crude piperidine product, and at the same time, convert the ammonia in the waste gas into ammonia water or ammonium sulfate, which has a very high market value. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The figure is a schematic diagram of a piperidine purification device according to one embodiment of the present invention.

[0027] Figure 2 This is a schematic diagram of a piperidine purification device according to another embodiment of the present invention.

[0028] Description of reference numerals:

[0029] Separation device 100

[0030] First distillation device 200

[0031] Second distillation apparatus 300

[0032] Condenser 400

[0033] Condensate tank 500

[0034] Absorption tower 600 DETAILED DESCRIPTION

[0035] Typical embodiments that embody the features and advantages of the present invention will be described in detail in the following description. It should be understood that the present invention can have various variations in different embodiments without departing from the scope of the present invention, and the descriptions and illustrations therein are essentially for illustrative purposes rather than for limiting the present invention. Among them, "first", "second", etc. are used to distinguish multiple processes or products with the same name, but are not intended to limit them.

[0036] It should be understood that the "connected" described in the present application document can be a direct connection or an indirect connection. In the indirect connection mode, for example, the connection can be achieved through a pump or the like, so as to transport the substance to be transported from the previous device to the next device. It should be understood that the " / " described in the present application document represents an "or" relationship, and the content before the " / " in the same sentence description corresponds to the content after the " / " corresponding to each other.

[0037] A first aspect of the present invention provides a method for purifying piperidine, comprising:

[0038] performing gas-liquid separation on a crude piperidine product containing bio-based pentamethylenediamine, bio-based piperidine, water and ammonia to obtain a gas phase and a liquid phase;

[0039] The liquid phase is distilled in the following manner (a) or (b):

[0040] (a) liquid phase is subjected to a first distillation to remove light constituents, the collected feed liquid is subjected to a second distillation to remove heavy constituents, and the distillate is condensed to obtain the purifying piperidine product;

[0041] (b) subjecting the liquid phase to a first distillation to remove heavy components, subjecting the distilled fraction to a second distillation to remove light components, and collecting the feed liquid to be the purified piperidine product.

[0042] In one embodiment, the piperidine content in the crude piperidine product is above 50%, for example, above 60%, above 70%, above 80%, above 90%, etc.

[0043] In the present invention, the light components include ammonia, water and other substances.

[0044] In the present invention, the heavy components include unreacted bio-based pentamethylenediamine raw materials, pyridine and other substances.

[0045] In one embodiment of the present invention, the distillation treatment is carried out in manner (a) to obtain a purified piperidine product.

[0046] The present invention can remove light components by subjecting the liquid phase to a first distillation. In the embodiment (a) of the present invention, the liquid collected by the first distillation can also be subjected to an azeotropic distillation operation.

[0047] In one embodiment, in method (a), the first distillation can be selected from one of kettle distillation, falling film distillation, tower distillation, scraper distillation, molecular distillation and short path distillation.

[0048] In a specific embodiment of the present invention, when the first distillation is kettle distillation, falling film distillation, tower distillation or scraper distillation, the distillation pressure is controlled to be 1-101 KPa and the temperature is 25-105°C. For example, the distillation pressure is controlled to be 101 KPa and the temperature can be 101°C, 102°C, 103°C, or 104°C.

[0049] In another specific embodiment of the present invention, when the first distillation is molecular distillation or short-path distillation, the pressure of the main evaporator is controlled to be 1-101 KPa, the evaporation surface temperature is 25-100°C, and the condensation surface temperature is 0-26°C.

[0050] The invention performs a second distillation on the collected feed liquid to remove heavy components, and the distilled fraction is condensed to obtain a purified piperidine product.

[0051] In one embodiment, in mode (a), the second distillation can be selected from one of kettle distillation, falling film distillation, tower distillation, scraper distillation, molecular distillation and short path distillation.

[0052] In a specific embodiment of the present invention, when the second distillation is kettle distillation, falling film distillation, tower distillation or scraper distillation, the distillation pressure is controlled to be 1-101 KPa and the temperature is 25-145°C. For example, the distillation pressure is controlled to be 101 KPa and the temperature can be 120°C, 125°C, 130°C, 135°C, or 140°C.

[0053] In another specific embodiment of the present invention, when the second distillation is molecular distillation or short-path distillation, the pressure of the main evaporator is controlled to be 1-101 KPa, the evaporation surface temperature is 30-107°C, and the condensation surface temperature is -10 to 37°C.

[0054] In one embodiment, the purification method further includes: returning the liquid collected in method (a) to the first distillation for recycling. By recycling the liquid from which the light components have been removed to the first distillation, the light components can be completely removed, so that the extracted and purified piperidine product contains almost no impurities such as ammonia and water.

[0055] In one embodiment, the purification method further comprises: returning the heavy components removed in method (a) to the second distillation cycle for further distillation to remove the residual piperidine in the heavy components.

[0056] In one embodiment, the heavy components removed in method (a) are directly discharged.

[0057] In one embodiment, the purification method further comprises: returning part of the heavy components removed in method (a) to the second distillation cycle for reuse, and part of them are directly discharged.

[0058] In one embodiment of the present invention, the distillation treatment is carried out in manner (b) to obtain a purified piperidine product.

[0059] The present invention can remove heavy components by subjecting the liquid phase to the first distillation.

[0060] In one embodiment, in mode (b), the first distillation can be selected from one of kettle distillation, falling film distillation, tower distillation, scraper distillation, molecular distillation and short path distillation.

[0061] In a specific embodiment of the present invention, when the first distillation is kettle distillation, falling film distillation, tower distillation or scraper distillation, the distillation pressure is controlled to be 1-101 KPa and the temperature is controlled to be 25-145°C.

[0062] In another specific embodiment of the present invention, when the first distillation is molecular distillation or short-path distillation, the pressure of the main evaporator is controlled to be 1-101 KPa, the evaporation surface temperature is 28-110°C, and the condensation surface temperature is -10 to 35°C.

[0063] The present invention performs a second distillation on the distilled fraction to remove light components, and the collected feed liquid is the purified piperidine product.

[0064] In one embodiment, in mode (b), the second distillation can be selected from one of kettle distillation, falling film distillation, tower distillation, scraper distillation, molecular distillation and short path distillation.

[0065] In a specific embodiment of the present invention, when the second distillation is kettle distillation, falling film distillation, tower distillation or scraper distillation, the distillation pressure is controlled to be 1-101 KPa and the temperature is controlled to be 25-105°C.

[0066] In another specific embodiment of the present invention, when the second distillation is molecular distillation or short-path distillation, the pressure of the main evaporator is controlled to be 1-101 KPa, the evaporation surface temperature is 26-100°C, and the condensation surface temperature is 0-27°C.

[0067] In one embodiment, the purification method further comprises: returning the heavy components removed in method (b) to the first distillation cycle for further extraction of piperidine.

[0068] In one embodiment, the purification method further comprises: directly discharging the heavy components removed in method (b).

[0069] In one embodiment, the purification method further comprises: returning part of the heavy components removed in method (b) to the first distillation cycle for reuse, and part of them are directly discharged.

[0070] In one embodiment, the purification method further comprises: absorbing the separated gas phase with water and / or sulfuric acid to obtain ammonia water and / or ammonium sulfate. The crude piperidine product provided by the present invention contains ammonia gas, which can be recovered by absorbing it with water or sulfuric acid to obtain ammonia water and / or ammonium sulfate, thereby effectively realizing waste utilization.

[0071] The purification method of one embodiment of the present invention is suitable for a crude piperidine product containing bio-based pentamethylenediamine, bio-based piperidine, water and ammonia. Through two-stage distillation, the obtained product has high purity, low pentamethylenediamine content, low pyridine content, low water content and low platinum-cobalt color number; and the gas generated in the reaction process can be effectively recycled and utilized, and the ammonia therein is converted into ammonia water or ammonium sulfate, which has high market value and a simple overall process flow.

[0072] A second aspect of the present invention provides a piperidine purification device, comprising:

[0073] A separation device, used for performing gas-liquid separation on the crude piperidine product to obtain a gas phase and a liquid phase;

[0074] a first distillation device, for distilling the liquid phase to remove light components / heavy components;

[0075] a second distillation device, for distilling the collected feed liquid / distilled fraction to remove heavy components / light components to obtain a distillate / purified piperidine product; and

[0076] An optional condensation device is used to condense the distillate to obtain a purified piperidine product.

[0077] In a specific embodiment of the present invention, Figure 1 As shown, the piperidine purification equipment includes a separation device 100, a first distillation device 200, a second distillation device 300 and a condensation device. The separation device 100 is used for gas-liquid separation of the crude piperidine product to obtain a gas phase and a liquid phase. The liquid outlet of the separation device 100 is connected to the first inlet of the first distillation device 200. The first distillation device 200 and the second distillation device 300 are both provided with a gas phase outlet and a liquid phase outlet. The liquid phase outlet of the first distillation device 200 is connected to the first inlet of the second distillation device 300. The gas phase outlet of the second distillation device 300 is connected to the inlet of the condensation device through a pipeline. The outlet of the condensation device is used to derive the purified piperidine product.

[0078] In one embodiment, the liquid phase outlet of the first distillation device 200 is also connected to the second inlet of the first distillation device 200 to form a closed loop for completely removing the light components in the feed liquid.

[0079] In one embodiment, the liquid phase outlet of the second distillation apparatus 300 is connected to the second inlet of the second distillation apparatus 300 through a pipeline. In the present invention, the liquid phase outlet of the second distillation apparatus 300 is connected to the second inlet of the second distillation apparatus 300 to form a closed loop for further distilling the residual piperidine in the heavy component.

[0080] In one embodiment, a branch for discharging impurities is further provided on the pipeline connecting the liquid phase outlet of the second distillation device 300 and the second inlet of the second distillation device 300 .

[0081] In one embodiment, the condensing device includes a condenser 400 and a condensing tank 500 connected in sequence, wherein the condenser 400 is used to condense the fraction distilled from the second distillation device 300 to obtain a condensed liquid, and the condensing tank 500 is used to store the liquid. In the present invention, the condenser 400 and the condensing tank 500 can both be existing devices.

[0082] In another specific embodiment of the present invention, Figure 2 As shown, the piperidine purification equipment includes a separation device 100, a first distillation device 200 and a second distillation device 300, the liquid outlet of the separation device 100 is connected to the first inlet of the first distillation device 200, the first distillation device 200 and the second distillation device 300 are both provided with a gas phase outlet and a liquid phase outlet, the gas phase outlet of the first distillation device 200 is connected to the inlet of the second distillation device 300, and the liquid phase outlet of the second distillation device 300 is used to export the purified piperidine product.

[0083] In one embodiment, the liquid phase outlet of the first distillation apparatus 200 is connected to the second inlet of the first distillation apparatus 200 through a pipeline. In the present invention, the liquid phase outlet of the first distillation apparatus 200 is connected to the second inlet of the first distillation apparatus 200 to form a closed loop for further distilling the residual piperidine in the heavy component.

[0084] In one embodiment, a branch for discharging impurities is further provided on the pipeline connecting the liquid phase outlet of the first distillation device 200 and the second inlet of the first distillation device 200 .

[0085] In the present invention, Figure 1As shown in or 2, the purification equipment also includes at least one absorption tower 600 connected to the gas outlet of the separation device 100, which is used to absorb the separated gas phase with water / sulfuric acid to obtain ammonia water / ammonium sulfate, which can effectively realize the recovery and utilization of waste gas.

[0086] In one embodiment, the absorption tower 600 is provided with a water / acid inlet, a waste gas outlet and a material outlet.

[0087] In one embodiment, an adsorption filler layer is provided in the absorption tower, and the filler in the adsorption filler layer is a bulk filler or a structured filler.

[0088] In one embodiment, the bulk filler is selected from one of ball rings, Raschig rings, straight rings, step rings, rosettes and ball rings.

[0089] In one embodiment, the structured packing is selected from one of corrugated packing, grid-type packing and plate-type packing.

[0090] In the present invention, in order to further recover the separated gas phase (ammonia), one or more absorption towers can be set as needed. When multiple absorption towers are set, for example, 2 absorption towers or 3 absorption towers, all absorption towers can be used in series, and the waste gas not absorbed in the latter absorption tower can be recycled back to the previous absorption tower for repeated absorption. The water inlet / acid port is mainly used to introduce pure water or sulfuric acid to absorb ammonia to obtain ammonia water or ammonium sulfate.

[0091] In one embodiment, the separation device 100 may be an existing device as long as it can achieve gas-liquid separation of the crude piperidine product.

[0092] In one embodiment, the first distillation device 200 and the second distillation device 300 are independently one of an evaporation kettle, a falling film evaporator, an evaporation tower, a scraper evaporator and a molecular distillation device. The above distillation devices are all existing devices.

[0093] In the present invention, a delivery pump can be arranged on the pipeline connecting the two devices as needed. For example, a delivery pump can be arranged on the pipeline connecting the liquid phase outlet of the second distillation device and the second inlet of the second distillation device to pump the heavy components removed by the second distillation device to the second distillation device for recycling; a delivery pump can be arranged on the outlet pipeline of the condensation tank to pump the stored liquid to the tank area.

[0094] A third aspect of the present invention provides a method for purifying piperidine, which uses the purification equipment as described above.

[0095] The fourth aspect of the present invention further provides a bio-based piperidine product, wherein the piperidine product is 100% bio-based, and the piperidine purity is ≥99.5%, and further ≥99.7%. In the present invention, 100% bio-based is substantially 100% bio-based carbon, specifically referring to that the source of C in the piperidine product is 100% bio-based.

[0096] In one embodiment, the content of pentamethylenediamine in the piperidine product is ≤100 ppm.

[0097] In a preferred embodiment, the piperidine product does not contain pentamethylenediamine.

[0098] In one embodiment, the pyridine content in the piperidine product is ≤1000 ppm, further ≤100 ppm, and further ≤10 ppm.

[0099] In a preferred embodiment, the piperidine product does not contain pyridine.

[0100] In one embodiment, the water content of the piperidine product is ≤0.2%, further ≤0.1%.

[0101] In one embodiment, the piperidine product has a platinum-cobalt color number of ≤8.

[0102] In one embodiment, the piperidine product has a density of 0.86-0.865 g / L.

[0103] The present invention also provides application of the piperidine product in the fields of rubber accelerators, pesticides and medicines.

[0104] In one embodiment, the rubber accelerator includes at least one of dipentamethylenethiuram tetrasulfide, dipentamethylenethiuram disulfide, piperidinium-1-piperidinyldithiocarboxylate, and dipentamethylenethiuram hexasulfide.

[0105] In one embodiment, the pesticide includes at least one of mepiquat and chloranil.

[0106] In one embodiment, the drug comprises at least one of minoxidil, roxatidine acetate hydrochloride and dipyridamole raw materials.

[0107] The following is a further description of the piperidine purification method according to one embodiment of the present invention by means of a specific example. The piperidine crude product used is provided by Shanghai Cathay Biotechnology Co., Ltd., and the test method used is as follows:

[0108] 1. Content of piperidine, pyridine and pentamethylenediamine

[0109] The content was determined by gas chromatography area normalization method. Agilent DB-1 capillary column (30m×320μm×1.0μm) was used.

[0110] Initial column temperature 70°C, maintained for 1 minute, increased to 230°C at a rate of 15°C / min, maintained for 5 minutes, injection port temperature 230°C

[0111] The FID detector temperature was 250°C, the carrier gas was hydrogen, the injection was split, the injection volume was 0.2 μl, ethanol was used as the injection solvent, and the contents of piperidine, pyridine, and pentamethylenediamine were calculated respectively by the area normalization method.

[0112] 2. Water content

[0113] Use a Karl Fischer titrator to measure the sample moisture content. First determine the water equivalent (F) g / mL of the Karl Fischer reagent, then weigh 5-10g of the sample, titrate to the endpoint, and calculate the moisture content by the consumed volume.

[0114] The average of the two parallel measurement results is taken as the measurement result, and the absolute difference between the two parallel measurement results shall not exceed 10% of the average value.

[0115] 3. Chroma

[0116] The Hazen chromaticity was directly measured using a HACH LICO620 benchtop colorimeter.

[0117] 4. Density

[0118] At 20°C, using a hydrometer (0.8-0.9 g / cm 3 ) is directly measured.

[0119] Example 1

[0120] This embodiment 1 provides a piperidine purification device, such as Figure 1 As shown, it includes a separation device 100, a first distillation device 200, a second distillation device 300, a condensation device and an absorption tower 600;

[0121] The separation device 100 is used to separate the crude piperidine product into gas and liquid to obtain a gas phase and a liquid phase. The liquid outlet of the separation device is connected to the first inlet of the first distillation device 200. The first distillation device 200 and the second distillation device 300 are both provided with a gas phase outlet and a liquid phase outlet. The liquid phase outlet of the first distillation device 200 is connected to the first inlet of the second distillation device 300. The gas phase outlet of the second distillation device 300 is connected to the inlet of the condensation device through a pipeline. The outlet of the condensation device is used to derive the purified piperidine product.

[0122] The liquid phase outlet of the first distillation apparatus 200 is connected to the second inlet of the first distillation apparatus 200 to form a closed loop;

[0123] The liquid phase outlet of the second distillation apparatus 300 is connected to the second inlet of the second distillation apparatus 300 through a pipeline;

[0124] A branch for discharging impurities is also provided on the pipeline connecting the liquid phase outlet of the second distillation device 300 and the second inlet of the second distillation device 300;

[0125] The condensing device includes a condenser 400 and a condensing tank 500 which are connected in sequence;

[0126] The gas outlet of the separation device 100 is connected to the inlet of the absorption tower 600. The absorption tower 600 is provided with a water / acid inlet, a waste gas outlet and a material outlet. An adsorption packing layer is provided in the absorption tower 600. The packing in the adsorption packing layer is a bulk packing or a structured packing. The bulk packing is selected from one of ball rings, Raschig rings, straight rings, step rings, rosettes and ball rings. The structured packing is selected from corrugated packing, grid-type packing and plate-type packing.

[0127] Example 2

[0128] This embodiment 2 provides another piperidine purification device, such as Figure 2 As shown, it includes a separation device 100, a first distillation device 200, a second distillation device 300 and an absorption tower 600;

[0129] The separation device 100 is used to separate the crude piperidine product into gas and liquid to obtain a gas phase and a liquid phase. The liquid outlet of the separation device is connected to the first inlet of the first distillation device 200. The first distillation device 200 and the second distillation device 300 are both provided with a gas phase outlet and a liquid phase outlet. The gas phase outlet of the first distillation device 200 is connected to the inlet of the second distillation device 300. The liquid phase outlet of the second distillation device 300 is used to derive a purified piperidine product.

[0130] The liquid phase outlet of the first distillation apparatus 200 is connected to the second inlet of the first distillation apparatus 200 through a pipeline;

[0131] A branch for discharging impurities is also provided on the pipeline connecting the liquid phase outlet of the first distillation device 200 and the second inlet of the first distillation device 200;

[0132] The gas outlet of the separation device 100 is connected to the inlet of the absorption tower 600. The absorption tower 600 is provided with a water / acid inlet, a waste gas outlet and a material outlet. An adsorption packing layer is provided in the absorption tower 600. The packing in the adsorption packing layer is a bulk packing or a structured packing. The bulk packing is selected from one of ball rings, Raschig rings, straight rings, step rings, rosettes and ball rings. The structured packing is selected from one of corrugated packing, grid-type packing and plate-type packing.

[0133] Example 3-1

[0134] Example 3-1 uses the same purification equipment as Example 1; the purification method of bio-based piperidine in Example 3-1 is as follows:

[0135] The crude piperidine product containing bio-based pentamethylenediamine, bio-based piperidine, water and ammonia, wherein the content of piperidine is 92.2%, is introduced into the separation device 100 for gas-liquid separation to obtain a gas phase and a liquid phase;

[0136] The liquid phase is passed into the first distillation device (scraper evaporator) 200 for the first distillation to remove light components, the light components are mainly ammonia and water, the temperature of the first distillation is 102° C., the pressure is 101 KPa, and the liquid from which the light components are removed is collected;

[0137] The collected liquid is passed into the second distillation equipment (evaporator) 300 for the second distillation to remove the heavy components, which are mainly pentamethylenediamine. The temperature of the second distillation is 140°C and the pressure is 101 KPa. The distillate from which the heavy components are removed is passed into the condenser 400 for condensation, and then the condensed liquid is passed into the condensation tank 500 for storage, and the purified piperidine product is taken out from the condensation tank 500.

[0138] The gas phase is introduced into the absorption tower 600 for absorption with water / sulfuric acid, and ammonia water or ammonium sulfate is discharged from the bottom of the tower. The unabsorbed tail gas is sent to the flare system for treatment through the top of the tower.

[0139] Example 3-2

[0140] Example 3-2 uses the same purification equipment as Example 1; the purification method of bio-based piperidine in Example 3-2 is as follows:

[0141] The crude piperidine product containing bio-based pentamethylenediamine, bio-based piperidine, water and ammonia, wherein the content of piperidine is 91.8%, is introduced into the separation device 100 for gas-liquid separation to obtain a gas phase and a liquid phase;

[0142] The liquid phase is passed into the first distillation device (scraper evaporator) 200 for the first distillation to remove light components, the light components are mainly ammonia and water, the temperature of the first distillation is 103° C., the pressure is 101 KPa, and the liquid from which the light components are removed is collected;

[0143] The collected liquid is passed into the second distillation equipment (molecular distillation device) 300 for molecular distillation to remove heavy components, the heavy components are mainly pentamethylenediamine, the pressure is 20KPa (absolute pressure), the condensation surface temperature is 25°C, the evaporation surface temperature is 100°C, the distillate after removing the heavy components is passed into the condenser 400 for condensation, and then the condensed liquid is passed into the condensation tank 500 for storage, and the purified piperidine product is extracted from the condensation tank 500.

[0144] The gas phase is introduced into the absorption tower 600 for absorption with water / sulfuric acid, and ammonia water or ammonium sulfate is discharged from the bottom of the tower. The unabsorbed tail gas is sent to the flare system for treatment through the top of the tower.

[0145] Example 3-3

[0146] Example 3-3 uses the same purification equipment as Example 1; the purification method of bio-based piperidine in Example 3-3 is as follows:

[0147] The crude piperidine product containing bio-based pentamethylenediamine, bio-based piperidine, water and ammonia, wherein the content of piperidine is 91.5%, is introduced into the separation device 100 for gas-liquid separation to obtain a gas phase and a liquid phase;

[0148] The liquid phase is passed into the first distillation device (molecular distillation device) 200 for molecular distillation to remove light components, the light components are mainly ammonia and water, the pressure is 30KPa (absolute pressure), the condensation surface temperature is 25°C, the evaporation surface temperature is 70°C, and the liquid from which the light components are removed is collected;

[0149] The collected liquid is passed into the second distillation equipment (molecular distillation device) 300 for molecular distillation to remove heavy components, the heavy components are mainly pentamethylenediamine, the pressure is 20KPa (absolute pressure), the condensation surface temperature is 25°C, and the evaporation surface temperature is 105°C. The distillate from which the heavy components are removed is passed into the condenser 400 for condensation, and then the condensed liquid is passed into the condensation tank 500 for storage, and the purified piperidine product is extracted from the condensation tank 500.

[0150] The gas phase is introduced into the absorption tower 600 for absorption with water / sulfuric acid, and ammonia water or ammonium sulfate is discharged from the bottom of the tower. The unabsorbed tail gas is sent to the flare system for treatment through the top of the tower.

[0151] Example 4-1

[0152] Example 4-1 uses the same purification equipment as Example 2; the purification method of bio-based piperidine in Example 4-1 is as follows:

[0153] The crude piperidine product containing bio-based pentamethylenediamine, bio-based piperidine, water and ammonia, wherein the content of piperidine is 92.2%, is introduced into the separation device 100 for gas-liquid separation to obtain a gas phase and a liquid phase;

[0154] The liquid phase is passed into the first distillation device (scraper evaporator) 200 for the first distillation to remove the heavy components, the heavy components are mainly pentamethylenediamine, the temperature of the first distillation is 140° C., the pressure is 101 KPa, and the distilled fraction is collected;

[0155] The collected fractions are introduced into the second distillation equipment (evaporator) 300 for second distillation to remove light components, which are mainly ammonia and water. The temperature of the second distillation is 101° C. and the pressure is 101 KPa. The obtained feed liquid is the purified piperidine product.

[0156] The gas phase is introduced into the absorption tower 600 for absorption with water / sulfuric acid, and ammonia water or ammonium sulfate is discharged from the bottom of the tower. The unabsorbed tail gas is sent to the flare system for treatment through the top of the tower.

[0157] Example 4-2

[0158] Example 4-2 uses the same purification equipment as Example 2; the purification method of bio-based piperidine in Example 4-2 is as follows:

[0159] The crude piperidine product containing bio-based pentamethylenediamine, bio-based piperidine, water and ammonia, wherein the content of piperidine is 91.8%, is introduced into the separation device 100 for gas-liquid separation to obtain a gas phase and a liquid phase;

[0160] The liquid phase is passed into the first distillation device (scraper evaporator) 200 for the first distillation to remove the heavy components, the heavy components are mainly pentamethylenediamine, the temperature of the first distillation is 138° C., the pressure is 101 KPa, and the distilled fraction is collected;

[0161] The collected fractions are introduced into the second distillation equipment (molecular distillation device) 300 for molecular distillation to remove light components, which are mainly ammonia and water. The pressure is 29.5 KPa (absolute pressure), the condensation surface temperature is 25.5°C, and the evaporation surface temperature is 70°C. The obtained liquid is the purified piperidine product.

[0162] The gas phase is introduced into the absorption tower 600 for absorption with water / sulfuric acid, and ammonia water or ammonium sulfate is discharged from the bottom of the tower. The unabsorbed tail gas is sent to the flare system for treatment through the top of the tower.

[0163] Example 4-3

[0164] Example 4-3 uses the same purification equipment as Example 2; the purification method of bio-based piperidine in Example 4-3 is as follows:

[0165] The crude piperidine product containing bio-based pentamethylenediamine, bio-based piperidine, water and ammonia, wherein the content of piperidine is 91.5%, is introduced into the separation device 100 for gas-liquid separation to obtain a gas phase and a liquid phase;

[0166] The liquid phase is passed into the first distillation device (molecular distillation device) 200 for molecular distillation to remove heavy components, the heavy components are mainly pentamethylenediamine, the pressure is 21KPa (absolute pressure), the condensation surface temperature is 25.5°C, the evaporation surface temperature is 93°C, and the distilled fraction is collected;

[0167] The collected fractions are introduced into the second distillation equipment (molecular distillation device) 300 for molecular distillation to remove light components, which are mainly ammonia and water. The pressure is 30.5 KPa (absolute pressure), the condensation surface temperature is 24.5°C, and the evaporation surface temperature is 71°C. The obtained liquid is the purified piperidine product.

[0168] The gas phase is introduced into the absorption tower 600 for absorption with water / sulfuric acid, and ammonia water or ammonium sulfate is discharged from the bottom of the tower. The unabsorbed tail gas is sent to the flare system for treatment through the top of the tower.

[0169] Example 5

[0170] The crude piperidine product introduced into the separation device 100 is the same as that in Example 3-1, and a gas phase and a liquid phase are obtained;

[0171] The liquid phase is passed into the first distillation device (scraper evaporator) 200 for the first distillation to remove light components, the light components are mainly ammonia and water, the temperature of the first distillation is 102° C., the pressure is 101 KPa, and the liquid from which the light components are removed is collected;

[0172] The collected liquid is passed into the second distillation equipment (molecular distillation device) 300 for molecular distillation to remove heavy components, the heavy components are mainly pentamethylenediamine, the pressure is 20.5 KPa (absolute pressure), the condensation surface temperature is 25.3°C, the evaporation surface temperature is 101°C, the distillate from which the heavy components are removed is passed into the condenser 400 for condensation, and then the condensed liquid is passed into the condensation tank 500 for storage, and the purified piperidine product is extracted from the condensation tank 500.

[0173] The gas phase treatment method is the same as that of Example 3-1.

[0174] Example 6

[0175] The crude piperidine product introduced into the separation device 100 is the same as that in Example 3-1, and a gas phase and a liquid phase are obtained;

[0176] The liquid phase is passed into the first distillation device (molecular distillation device) 200 for molecular distillation to remove light components, the light components are mainly ammonia and water, the pressure is 30.3 KPa (absolute pressure), the condensation surface temperature is 25.4 ° C, the evaporation surface temperature is 75 ° C, and the liquid from which the light components are removed is collected;

[0177] The collected liquid is passed into the second distillation equipment (molecular distillation device) 300 for molecular distillation to remove heavy components, the heavy components are mainly pentamethylenediamine, the pressure is 20.3 KPa (absolute pressure), the condensation surface temperature is 25.3 ° C, the evaporation surface temperature is 98 ° C, the distillate from the removal of heavy components is passed into the condenser 400 for condensation, and then the condensed liquid is passed into the condensation tank 500 for storage, and the purified piperidine product is extracted from the condensation tank.

[0178] The gas phase treatment method is the same as that of Example 3-1.

[0179] Comparative Example 1

[0180] The crude piperidine product introduced into the separation device 100 is the same as that in Example 3-1, and a gas phase and a liquid phase are obtained;

[0181] The liquid phase is passed into a distillation device (scraper evaporator) for distillation to remove heavy components, the heavy components are mainly pentamethylenediamine, the distillation temperature is 144°C, the pressure is 101KPa, the distillate after the heavy components are removed is passed into a condenser for condensation, and then the condensed liquid is passed into a condensation tank for storage, and the purified piperidine product is extracted from the condensation tank.

[0182] The gas phase treatment method is the same as that of Example 3-1.

[0183] The bio-based piperidine products purified in the above examples and comparative examples were subjected to relevant performance tests, and the specific results are shown in Table 1.

[0184] Table 1 Bio-based piperidine product performance table

[0185]

[0186]

[0187] Unless otherwise specified, the terms used in the present invention have the meanings commonly understood by those skilled in the art. The embodiments described in the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. Those skilled in the art may make various other substitutions, changes and improvements within the scope of the present invention. Therefore, the present invention is not limited to the above embodiments, but is only limited by the claims.

Claims

1. A method for purifying piperidine, characterized in that: include: performing gas-liquid separation on a crude piperidine product containing bio-based pentamethylenediamine, bio-based piperidine, water and ammonia to obtain a gas phase and a liquid phase; The liquid phase is distilled in the following manner (a) or (b): (a) liquid phase is subjected to a first distillation to remove light constituents, the collected feed liquid is subjected to a second distillation to remove heavy constituents, and the distillate is condensed to obtain the purifying piperidine product; (b) subjecting the liquid phase to a first distillation to remove heavy components, subjecting the distilled fraction to a second distillation to remove light components, and collecting the feed liquid to be the purified piperidine product.

2. The purification method according to claim 1, characterized in that In the modes (a) and (b), the first distillation and the second distillation can be independently selected from one of kettle distillation, falling film distillation, tower distillation, scraper distillation, molecular distillation and short path distillation.

3. The purification method according to claim 2, characterized in that In mode (a), when the first distillation is kettle distillation, falling film distillation, tower distillation or scraper distillation, the distillation pressure is controlled to be 1-101 KPa and the temperature is 25-105° C.; When the first distillation is molecular distillation or short-path distillation, the pressure of the main evaporator is controlled to be 1-101 KPa, the evaporation surface temperature is 25-100° C., and the condensation surface temperature is 0-26° C.; When the second distillation is kettle distillation, falling film distillation, tower distillation or scraper distillation, the distillation pressure is controlled to be 1-101 KPa and the temperature is 25-145° C.; When the second distillation is molecular distillation or short-path distillation, the pressure of the main evaporator is controlled to be 1-101 KPa, the evaporation surface temperature is 30-107°C, and the condensation surface temperature is -10 to 37°C.

4. The purification method according to claim 2, characterized in that In mode (b), when the first distillation is kettle distillation, falling film distillation, tower distillation or scraper distillation, the distillation pressure is controlled to be 1-101 KPa and the temperature is 25-145° C.; When the first distillation is molecular distillation or short-path distillation, the pressure of the main evaporator is controlled to be 1-101 KPa, the evaporation surface temperature is 28-110° C., and the condensation surface temperature is -10-35° C.; When the second distillation is kettle distillation, falling film distillation, tower distillation or scraper distillation, the distillation pressure is controlled to be 1-101 KPa and the temperature is 25-105° C.; When the second distillation is molecular distillation or short-path distillation, the pressure of the main evaporator is controlled to be 1-101 KPa, the evaporation surface temperature is 26-100° C., and the condensation surface temperature is 0-27° C.

5. The purification method according to claim 1, characterized in that The purification method further comprises: subjecting the gas phase to absorption treatment with water and / or sulfuric acid to obtain ammonia water and / or ammonium sulfate; and / or, The purification method further comprises: returning the collected liquid in method (a) to the first distillation cycle for recycling, and / or, returning the heavy components removed in method (a) to the second distillation cycle for recycling, and / or, directly discharging the heavy components removed in method (a); and / or, The purification method further comprises: returning the heavy components removed in method (b) to the first distillation for recycling, and / or directly discharging the heavy components removed in method (b).

6. A piperidine purification device, characterized in that: include: A separation device, used for performing gas-liquid separation on the crude piperidine product to obtain a gas phase and a liquid phase; a first distillation device, for distilling the liquid phase to remove light components / heavy components; A second distillation device is used to distill the collected feed liquid / distilled fraction to remove heavy components / light components to obtain a distillate / purified piperidine product; as well as An optional condensation device is used to condense the distillate to obtain a purified piperidine product.

7. The purification device according to claim 6, characterized in that The liquid outlet of the separation device is connected to the first inlet of the first distillation device, the first distillation device and the second distillation device are both provided with a gas phase outlet and a liquid phase outlet, the liquid phase outlet of the first distillation device is connected to the first inlet of the second distillation device, the gas phase outlet of the second distillation device is connected to the inlet of the condensation device through a pipeline, and the outlet of the condensation device is used to derive a purified piperidine product; and / or, The liquid phase outlet of the first distillation apparatus is connected to the second inlet of the first distillation apparatus to form a closed loop; and / or, The liquid phase outlet of the second distillation apparatus is connected to the second inlet of the second distillation apparatus through a pipeline; and / or, A branch for discharging impurities is also provided on the pipeline connecting the liquid phase outlet of the second distillation device and the second inlet of the second distillation device.

8. The purification device according to claim 6, characterized in that The liquid outlet of the separation device is connected to the first inlet of the first distillation device, the first distillation device and the second distillation device are both provided with a gas phase outlet and a liquid phase outlet, the gas phase outlet of the first distillation device is connected to the inlet of the second distillation device, and the liquid phase outlet of the second distillation device is used to derive a purified piperidine product; and / or, The liquid phase outlet of the first distillation apparatus is connected to the second inlet of the first distillation apparatus through a pipeline; and / or, A branch for discharging impurities is also provided on the pipeline connecting the liquid phase outlet of the first distillation device and the second inlet of the first distillation device.

9. The purification device according to claim 6, characterized in that The first distillation device and the second distillation device are independently selected from one of an evaporation kettle, a falling film evaporator, an evaporation tower, a scraper evaporator and a molecular distillation device; and / or, the condensation device includes a condenser and a condensation tank connected in sequence.

10. The purification device according to any one of claims 6 to 9, characterized in that The purification equipment further comprises at least one absorption tower connected to the gas outlet of the separation device, which is used to absorb the separated gas phase with water / sulfuric acid to obtain ammonia water / ammonium sulfate; The absorption tower is provided with a water / acid inlet, a waste gas outlet and a material outlet; and / or, An adsorption filler layer is provided in the absorption tower, and the filler in the adsorption filler layer is a bulk filler or a structured filler; The bulk filler is selected from one of ball rings, Raschig rings, straight rings, step rings, rosettes and ball rings; The structured packing is selected from one of corrugated packing, grid type packing and plate type packing.

11. A method for purifying piperidine, characterized in that: It adopts the purification equipment described in any one of claims 6-10.

12. The piperidine product obtained by the purification method according to any one of claims 1 to 5 and 11, characterized in that: The piperidine product is 100% bio-based, and the piperidine purity is ≥ 99.5%, further ≥ 99.7%; and / or, The content of pentamethylenediamine in the piperidine product is ≤100ppm; and / or, The pyridine content in the piperidine product is ≤1000ppm, further ≤100ppm, further ≤10ppm; and / or, The water content of the piperidine product is ≤0.2%, further ≤0.1%; and / or, The platinum-cobalt color number of the piperidine product is ≤8; and / or, The piperidine product has a density of 0.86-0.865 g / L.

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