Process and apparatus for the continuous synthesis of sebacic acid to sebacinderivatives

Abstract

The application provides a method and device for continuously synthesizing sebacic nitrile from sebacic acid. The method comprises continuously reacting in n reaction kettles, wherein raw materials containing sebacic acid, ammonia and a catalyst are introduced into a first reaction kettle for reaction, and the product of an (n-1)th reaction kettle is introduced into an nth reaction kettle for reaction, and n is greater than or equal to 2. The method can effectively improve the product quality of sebacic nitrile, greatly reduce energy consumption, and has high yield, few impurities, light color and high quality.

Description

Technical Field

[0001] This invention belongs to the field of fine chemical product technology, specifically relating to an apparatus and method for the continuous synthesis of sebacite from sebacite. Background Technology

[0002] Sebaconitrile is an important chemical raw material, mainly used in the synthesis of nylon 1010, and also used in the pharmaceutical and dyeing industries. Nylon 1010, chemically known as polydecanoic acid decylamine, abbreviated as 1010 (PA1010), is a nylon product unique to my country. PA1010 is obtained by the polycondensation of decylamine and sebacic acid, while decylamine is derived from sebaconitrile.

[0003] There are three main existing methods for preparing sebacin: 1. Condensation reaction of acetonitrile and 1,6-dibromohexane, but the yield is low (50%-70%), and 1,6-dibromohexane is expensive, making it unsuitable for industrial production; 2. Preparation by adding trifluoroacetic anhydride dehydrating agent to sebacinamide, but the dehydrating agent is volatile, easily hydrolyzed, and irritating, requiring stringent application conditions, making it suitable only for laboratory preparation of sebacin and unsuitable for industrial production; 3. Preparation by ammoniation dehydration of sebaic acid using an intensified temperature method. In the process of preparing sebacin by ammoniation dehydration of sebaic acid, the ammoniation step is crucial to ensuring the purity of the finished product and production efficiency. The ammoniation step itself has a long reaction time and complex operation steps such as temperature control. In order to ensure that the reaction proceeds fully, ammonia gas is generally introduced and heated in stages. This results in a long reaction time and difficulty in controlling the reaction temperature, which leads to incomplete ammoniation reaction, poor selectivity, carbonization of organic matter, many by-products, low production efficiency, and difficulty in ensuring the production precision of the finished product. Summary of the Invention

[0004] To address the problems existing in the prior art, the present invention aims to provide a multi-reactor continuous temperature-controlled nitrification apparatus and method for the synthesis of sebacite from sebacite, which can effectively improve the product quality of sebacite, greatly reduce energy consumption, and achieve high yield, low impurities, light color of finished product, and excellent quality.

[0005] Therefore, a first aspect of the present invention provides a method for the continuous synthesis of sebacite from sebacite, the method comprising a continuous reaction in n reaction vessels, wherein a raw material containing sebacite, ammonia and a catalyst is fed into a first reaction vessel for reaction, and the product from the (n-1)th reaction vessel is fed into the nth reaction vessel for reaction, where n ≥ 2.

[0006] In some implementations, the value of n satisfies 5 ≤ ​​n ≤ 20, for example, 5, 6, 8, 10, 12, 14, 16, 18, 20 or any value between them. In some preferred implementations, 6 ≤ n ≤ 10.

[0007] In some embodiments, the product of the (n-1)th reactor enters the nth reactor by overflow.

[0008] In some embodiments, the temperature T1 of the first reactor satisfies 130°C ≤ T1 ≤ 270°C, for example, 130°C, 150°C, 170°C, 190°C, 210°C, 230°C, 250°C, 270°C, or any value between them. Preferably, 170°C ≤ T1 ≤ 250°C.

[0009] In some embodiments, the ammonia flow rate of the first reactor is V1, satisfying 5 L / h ≤ V1 ≤ 50 L / h, for example, 10 L / h, 20 L / h, 30 L / h, 40 L / h, 50 L / h, or any value between them. Preferably, 5 L / h ≤ V1 ≤ 30 h / L.

[0010] In some embodiments, the temperature of the (n-1)th reactor is T. n-1 The temperature of the nth reactor is T. n Satisfying 0℃≤T n -T n-1 ≤80℃. In some embodiments, T n -T n-1 The value can be 0℃, 10℃, 20℃, 40℃, 60℃, 80℃, or any value in between. Preferably, 5℃ ≤ T n -T n-1 ≤60℃.

[0011] In some embodiments, the ammonia flow rate to the (n-1)th reactor is V. n-1 The temperature of the nth reactor is V. n Satisfying 0L / h≤V n-1 -V n ≤10L / h. In some implementations, V n-1 -V n The value can be 0 L / h, 2 L / h, 4 L / h, 6 L / h, 8 L / h, 10 L / h, or any value between them. Preferably, 0 L / h ≤ V n -V n-1 ≤5L / h.

[0012] In some implementations, the reactor temperature T of the nth reactor is... n Satisfying 130≤T n ≤500°C, for example, 130°C, 150°C, 200°C, 250°C, 300°C, 350°C, 400°C, 450°C, 500°C, or any value between them. In some preferred embodiments, 150 ≤ T n ≤450℃.

[0013] In some embodiments, the ammonia flow rate V to the nth reactor is... n Satisfying 2≤V n ≤50L / h, for example, 2L / h, 5L / h, 10L / h, 20L / h, 30L / h, 40L / h, 50L / h, or any value between them. In some preferred embodiments, 2≤V n ≤20L / h.

[0014] In some embodiments, the reaction time in each reactor is 2-9 hours, for example, 2 hours, 4 hours, 6 hours, 8 hours, 9 hours or any value between them.

[0015] In some embodiments, the molar ratio of sebacic acid to ammonia in the raw material containing sebacic acid, ammonia, and catalyst ranges from 1:(2-10), for example, 1:2, 1:4, 1:6, 1:8, 1:10, or any value between them. In a preferred embodiment, the molar ratio of sebacic acid to ammonia in the raw material containing sebacic acid, ammonia, and catalyst ranges from 1:(3.5-5), for example, 1:3.5, 1:4, 1:4.5, 1:5, or any value between them.

[0016] In some embodiments, the catalyst comprises a mixture of an acidic substance and silica gel, wherein the acidic substance is selected from at least one of sulfuric acid, nitric acid, acetic acid, phosphoric acid, p-toluenesulfonic acid, or an acidic resin, and the silica gel is selected from at least one of column chromatography silica gel or thin-film chromatography silica gel.

[0017] In some embodiments, the mass ratio of the acidic substance to the silica gel in the catalyst is 1:(0.2-5), for example, 1:0.2, 1:0.5, 1:1, 1:2, 1:3, 1:4, 1:5, or any value between them. In some preferred embodiments, the mass ratio of the acidic substance to the silica gel in the catalyst is 1:(0.5-3).

[0018] In some embodiments, the dosing rate of the sebacic acid is 100 kg / h to 500 kg / h, for example, 100 kg / h, 200 kg / h, 300 kg / h, 400 kg / h, 500 kg / h, or any value between them. In some preferred embodiments, the dosing rate of the sebacic acid is 200 kg / h to 400 kg / h.

[0019] In some embodiments, the catalyst is added at a rate of 2 kg / h to 100 kg / h, for example, 2 kg / h, 5 kg / h, 10 kg / h, 20 kg / h, 40 kg / h, 60 kg / h, 80 kg / h, 100 kg / h, or any value between them. In some preferred embodiments, the catalyst is added at a rate of 5 kg / h to 60 kg / h.

[0020] In some embodiments, the amount of catalyst added is 1%-30% of the mass of sebacic acid, for example, 1%, 5%, 10%, 15%, 20%, 25%, 30%, or any value between therewith. In some preferred embodiments, the amount of catalyst added is 2%-20% of the mass of sebacic acid; excess catalyst will result in a reduced product yield, more preferably 2%-10%.

[0021] In some embodiments, sebacic acid and catalyst are continuously added to the first reactor at the addition rate, while only ammonia is added to the nth reactor. The catalyst and sebacic acid are mixed evenly under stirring in the first reactor and continuously overflow into subsequent reactors.

[0022] In some embodiments, the method further includes purifying the reaction product of the nth reactor, the purification process comprising distilling the reaction product of the nth reactor in a distillation column.

[0023] In some embodiments, the reaction products of the nth reactor include a filtrate that has been cooled and had the catalyst removed.

[0024] In some embodiments, the distillation process includes first distilling the reaction product of the nth reactor in a first distillation column, and then distilling the bottom liquid of the first distillation column in a second distillation column.

[0025] In some embodiments, the reboiler temperature of the first distillation column is 120-350°C, for example, it can be 120°C, 150°C, 200°C, 250°C, 300°C, 350°C, or any value between them. In some preferred embodiments, the reboiler temperature of the first distillation column is 150-290°C.

[0026] In some embodiments, the top temperature of the first distillation column is 100-290°C, for example, it can be 100°C, 130°C, 180°C, 230°C, 290°C or any value between them. In some preferred embodiments, the top temperature of the first distillation column is 120-240°C.

[0027] In some embodiments, the reboiler temperature of the second distillation column is 130-360°C, for example, it can be 130°C, 160°C, 210°C, 260°C, 310°C, 360°C or any value between them. In some preferred embodiments, the reboiler temperature of the second distillation column is 160-300°C.

[0028] In some embodiments, the top temperature of the second distillation column is 110-300°C, for example, it can be 110°C, 150°C, 200°C, 250°C, 300°C or any value between them. In some preferred embodiments, the top temperature of the second distillation column is 130-250°C.

[0029] In some embodiments, the pressure of the first distillation column is 1-50 kPa, for example, it can be 1 kPa, 5 kPa, 10 kPa, 20 kPa, 30 kPa, 40 kPa, 50 kPa or any value between them.

[0030] In some embodiments, the pressure of the second distillation column is 1-50 kPa, for example, it can be 1 kPa, 5 kPa, 10 kPa, 20 kPa, 30 kPa, 40 kPa, 50 kPa or any value between them.

[0031] In some embodiments, the reflux ratio of the second distillation column is 1:(1-18), for example, it can be 1:1, 1:3, 1:6, 1:9, 1:12, 1:15, 1:18 or any value between them.

[0032] In a second aspect, the present invention provides an apparatus for the continuous synthesis of sebacate from sebacate. The apparatus comprises n reactors connected in series, wherein each reactor is provided with an overflow device at its upper part and a temperature control device at its lower part, and adjacent reactors are connected through the overflow device, where n≥2.

[0033] In some implementations, the value of n satisfies 5 ≤ ​​n ≤ 20, for example, 5, 6, 8, 10, 12, 14, 16, 18, 20 or any value between them. In some preferred implementations, 6 ≤ n ≤ 10.

[0034] In some embodiments, the apparatus further includes at least one distillation column connected to the nth reactor. In some embodiments, the number of distillation columns is 1-5, preferably 2-4.

[0035] In some embodiments, the reactor and the distillation column are connected via a crude nitrile tank.

[0036] In a third aspect, the present invention provides the application of the method described in the first aspect or the apparatus described in the second aspect in the production of sebacate.

[0037] Compared with the prior art, the method and apparatus for the continuous synthesis of sebacite from sebacite of the present invention have the following beneficial effects:

[0038] (1) Using multiple reactors for continuous reaction is more conducive to accurate temperature control, shortens the heating time, and improves the temperature control accuracy;

[0039] (2) Improved temperature control accuracy, avoiding overheating that could lead to increased impurities and carbonization;

[0040] (3) The process is continuous, the time is shorter, and the efficiency is higher.

[0041] (4) It reduces energy consumption, produces a higher purity product with a lighter color, and increases yield. Attached Figure Description

[0042] Figure 1 A diagram of an apparatus for the continuous synthesis of sebacite from sebacite according to some embodiments of this application is shown. Detailed Implementation

[0043] The present invention will be further described below through specific embodiments, but the scope of the present invention is not limited thereto.

[0044] An apparatus for the continuous synthesis of sebacate from sebacate, such as... Figure 1 As shown, it mainly includes a first reaction vessel, a second reaction vessel, ..., an nth reaction vessel, a crude nitrile tank, a first distillation column, a second distillation column, and a residual liquid distillation column connected in sequence.

[0045] The method for synthesizing sebacate using this apparatus includes the following steps:

[0046] (1) At room temperature and pressure, sebacic acid and catalyst are continuously added to the first reactor, and ammonia is introduced. The temperature is raised to 150-380℃ and held for 2-9 hours. The ammonia flow rate is 70-210L / h.

[0047] (2) The material overflows from the first reactor to the second reactor, the reactor temperature is 160-390℃, the residence time is 2-9h, and the ammonia flow rate is 60-180L / h.

[0048] (3) The material overflows from the second reactor to the third reactor, the reactor temperature is 170-400℃, the residence time is 2-9h, and the ammonia flow rate is 40-160L / h.

[0049] (4) The material overflows to the next reactor in sequence. The temperature of the nth reactor is 220-440℃. It stays for 2-9 hours and the ammonia flow rate is 10-100L / h.

[0050] (5) The material overflows from the nth reactor to the crude nitrile tank, cools and filters the catalyst, and the filtrate enters the No. 1 distillation column for distillation. The reactor temperature is controlled at 150-290℃, the top temperature at 120-240℃, and the pressure at 1-50Kpa. Low-boiling impurities in the crude nitrile are removed.

[0051] (6) The liquid in the kettle enters the No. 2 column for distillation. The kettle temperature is controlled at 160-300℃, the top temperature at 130-250℃, the pressure at 1-50Kpa, and the reflux ratio at 1:1-1:18. The positive boiling material is collected.

[0052] In the following examples and comparative examples, the color number of the target product sebacite was determined by the following method: 10g of sebacite was diluted to 50mL with ethanol, and the color number was determined according to GB / T 3143.

[0053] Example 1

[0054] Adopted and Figure 1 A similar apparatus was used for the continuous synthesis of sebacite from sebacite, comprising seven reactors connected in series. In the feed stream, the molar ratio of sebacite to ammonia was 1:3.5, and the catalyst was added at 20% of the mass of sebacite. The specific method is as follows:

[0055] At room temperature and pressure, sebacic acid is injected into the first reactor at a rate of 200 kg / h, nitric acid and column chromatography silica gel (nitric acid and column chromatography silica gel at a mass ratio of 1:1) are injected at a rate of 40 kg / h, ammonia gas is introduced at a rate of 15 L / h, the reactor temperature is 200℃, and the mixture is held for 2 hours before overflowing into the second reactor.

[0056] The temperature of the second reactor is 230℃. Ammonia gas is introduced at a rate of 13L / h and held for 2 hours. The gas is then overflowed into the third reactor.

[0057] The temperature of the third reactor is 270℃. Ammonia gas is introduced at a rate of 12L / h and held for 2 hours. The gas is then overflowed into the fourth reactor.

[0058] The fourth reactor is heated to 300℃, and ammonia gas is introduced at a rate of 10L / h. After 2 hours, the gas overflows into the fifth reactor.

[0059] The fifth reactor is heated to 330℃. Ammonia gas is introduced at a rate of 8L / h, held for 2 hours, and then overflowed into the sixth reactor.

[0060] The temperature of the sixth reactor is 350℃. Ammonia gas is introduced at a rate of 8L / h and held for 2 hours. The gas is then overflowed into the seventh reactor.

[0061] The seventh reactor is heated to 400℃. Ammonia gas is introduced at a rate of 7L / h, held for 2 hours, and then overflowed into the crude nitrile tank.

[0062] After filtration, the reaction solution enters the No. 1 distillation column for distillation. The foredistillate is collected under negative pressure at a column temperature of 170°C, and the top temperature is 165°C, at which point all of it is collected.

[0063] After the foredistillate is collected, the bottom liquid enters the No. 2 distillation column for rectification. The temperature is raised to 200°C, the top temperature is 180°C, the reflux ratio is 1:3, and the foredistillate is collected.

[0064] The temperature was raised to 270°C, and the distillate was collected and fed into the first reactor to continue the reaction.

[0065] The target product, sebacate, was obtained by forward distillation. The content was 99.2%, the color number was 3, and the yield was 98.3%.

[0066] Example 2

[0067] Adopted and Figure 1 A similar apparatus was used for the continuous synthesis of sebacite from sebacite, comprising 11 reactors connected in series. In the feed stream, the molar ratio of sebacite to ammonia was 1:4, and the catalyst was added at 4% of the mass of sebacite. The specific method is as follows:

[0068] At room temperature and pressure, sebacic acid is injected into the first reactor at a rate of 150 kg / h, nitric acid and column chromatography silica gel (nitric acid and column chromatography silica gel at a mass ratio of 1:1) are injected at a rate of 6 kg / h, ammonia gas is introduced at a rate of 8 L / h, the reactor temperature is 230℃, and the mixture is held for 3 hours before overflowing into the second reactor.

[0069] The second reactor is heated to 250℃. Ammonia gas is introduced at a rate of 7L / h and held for 3 hours. The gas is then overflowed into the third reactor.

[0070] The temperature of the third reactor is 270℃. Ammonia gas is introduced at a rate of 7L / h and held for 3 hours. The gas is then overflowed into the fourth reactor.

[0071] The temperature of the fourth reactor is 330℃. Ammonia gas is introduced at a rate of 5L / h, held for 3 hours, and then overflowed into the fifth reactor.

[0072] The fifth reactor is heated to 350℃. Ammonia gas is introduced at a rate of 5L / h and held for 3 hours. The gas is then overflowed into the sixth reactor.

[0073] The temperature of the sixth reactor is 380℃. Ammonia gas is introduced at a rate of 5L / h and held for 3 hours. The gas is then overflowed into the seventh reactor.

[0074] The temperature of the seventh reactor is 390℃. Ammonia gas is introduced at a rate of 5L / h and held for 3 hours. The gas is then overflowed into the eighth reactor.

[0075] The temperature of the eighth reactor is 390℃. Ammonia gas is introduced at a rate of 5L / h, held for 3 hours, and then overflowed into the ninth reactor.

[0076] The temperature of the ninth reactor is 390℃. Ammonia gas is introduced at a rate of 5L / h and held for 3 hours. The gas is then overflowed into the tenth reactor.

[0077] The temperature of the tenth reactor is 390℃. Ammonia gas is introduced at a rate of 5L / h, held for 3 hours, and then overflowed into the eleventh reactor.

[0078] The temperature of the eleventh reactor is 410℃. Ammonia gas is introduced at a rate of 5L / h and held for 3 hours. The overflow is then transferred to the crude nitrile tank.

[0079] After filtration, the reaction solution enters the No. 1 distillation column for distillation. The foredistillate is collected under negative pressure at a column temperature of 150°C, and the top temperature is 130°C. All of the distillate is collected.

[0080] After the foredistillate is collected, the bottom liquid enters the No. 2 distillation column for rectification. The temperature is raised to 180°C, the top temperature is 170°C, the reflux ratio is 1:8, and the foredistillate is collected.

[0081] The temperature was raised to 240°C, and the distillate was collected and fed into the first reactor to continue the reaction.

[0082] The target product, sebacate, was obtained by forward distillation, with a purity of 99.8%, color number 2, and a yield of 99.2%.

[0083] Example 3

[0084] Adopted and Figure 1 A similar apparatus was used for the continuous synthesis of sebacite from sebacite, comprising nine reactors connected in series. In the feed stream, the molar ratio of sebacite to ammonia was 1:5, and the catalyst was added at 2% of the mass of sebacite. The specific method is as follows:

[0085] At room temperature and pressure, sebacic acid was injected into the first reactor at a rate of 180 kg / h, nitric acid and column chromatography silica gel (nitric acid and column chromatography silica gel at a mass ratio of 1:1) were injected at a rate of 4 kg / h, ammonia gas was introduced at a rate of 15 L / h, the reactor temperature was 230℃, and the mixture was held for 9 hours before overflowing into the second reactor.

[0086] The second reactor is heated to 250℃, and ammonia gas is introduced at a rate of 13L / h. After 9 hours, the gas overflows into the third reactor.

[0087] The temperature of the third reactor is 270℃. Ammonia gas is introduced at a rate of 12L / h and held for 9 hours. The gas is then overflowed into the fourth reactor.

[0088] The temperature of the fourth reactor is 330℃. Ammonia gas is introduced at a rate of 12L / h and held for 9 hours. The gas is then overflowed into the fifth reactor.

[0089] The fifth reactor is heated to 350℃, and ammonia gas is introduced at a rate of 10L / h. After 9 hours, the gas overflows into the sixth reactor.

[0090] The temperature of the sixth reactor is 380℃. Ammonia gas is introduced at a rate of 10L / h and held for 9 hours. The gas is then overflowed into the seventh reactor.

[0091] The temperature of the seventh reactor is 390℃. Ammonia gas is introduced at a rate of 7L / h and held for 9 hours. The gas is then overflowed into the eighth reactor.

[0092] The temperature of the eighth reactor is 390℃. Ammonia gas is introduced at a rate of 5L / h and held for 9 hours. The gas is then overflowed into the ninth reactor.

[0093] The temperature of the ninth reactor is 410℃. Ammonia gas is introduced at a rate of 5L / h and held for 9 hours. The overflow is then transferred to the crude nitrile tank.

[0094] After filtration, the reaction solution enters the No. 1 distillation column for distillation. The foredistillate is collected under negative pressure at a column temperature of 150°C, and the top temperature is 130°C. All of the distillate is collected.

[0095] After the foredistillate is collected, the bottom liquid enters the No. 2 distillation column for rectification. The temperature is raised to 180°C, the top temperature is 170°C, the reflux ratio is 1:8, and the foredistillate is collected.

[0096] The temperature was raised to 240°C, and the distillate was collected and fed into the first reactor to continue the reaction.

[0097] The target product, sebacate, was obtained by forward distillation. The purity was 99.7%, the color number was 3, and the yield was 98.1%.

[0098] Example 4

[0099] Sebacic acid was continuously synthesized into sebaconitrile using a similar apparatus and method as in Example 1, the only difference being that a total of five reactors were connected in series. The conditions for each reactor were as follows:

[0100] At room temperature and pressure, sebacic acid is injected into the first reactor at a rate of 150 kg / h, nitric acid and column chromatography silica gel (nitric acid and column chromatography silica gel at a mass ratio of 1:1) are injected at a rate of 30 kg / h, ammonia gas is introduced at a rate of 15 L / h, the reactor temperature is 200℃, and the mixture is held for 2 hours before overflowing into the second reactor.

[0101] The second reactor is heated to 275℃. Ammonia gas is introduced at a rate of 13L / h and held for 2 hours before overflowing into the third reactor.

[0102] The temperature of the third reactor is 355℃. Ammonia gas is introduced at a rate of 12L / h and held for 2 hours. The gas is then overflowed into the fourth reactor.

[0103] The temperature of the fourth reactor is 425℃. Ammonia gas is introduced at a rate of 10L / h, held for 2 hours, and then overflowed into the fifth reactor.

[0104] The fifth reactor was heated to 485℃. Ammonia gas was introduced at a rate of 8L / h and held for 2 hours before overflowing into the crude nitrile tank.

[0105] After distillation, the forward distillate yielded the target product, sebacate, with a content of 93.5%, a color number of 15, and a yield of 84.7%.

[0106] Example 5

[0107] Sebacic acid was continuously synthesized into sebaconitrile using a similar apparatus and method as in Example 1, the only difference being that three reactors were connected in series. The conditions for each reactor were as follows:

[0108] At room temperature and pressure, sebacic acid is injected into the first reactor at a rate of 100 kg / h, nitric acid and silica gel for column chromatography are injected at a rate of 20 kg / h, and ammonia is introduced at a rate of 15 L / h. The reactor temperature is 200℃, and the mixture is held for 2 hours before overflowing into the second reactor.

[0109] The second reactor is heated to 270℃. Ammonia gas is introduced at a rate of 12L / h and held for 2 hours before overflowing into the third reactor.

[0110] The third reactor is heated to 400℃. Ammonia gas is introduced at a rate of 7L / h and held for 2 hours before overflowing into the crude nitrile tank.

[0111] After distillation, the forward distillate yielded the target product, sebacate, with a purity of 98.9%, color number 14, and a yield of 98.3%.

[0112] Example 6

[0113] Sebacic acid was continuously synthesized into sebaconitrile using a similar apparatus and method as in Example 1, the only difference being that a total of 15 reactors were connected in series. The conditions for each reactor were as follows:

[0114] At room temperature and pressure, sebacic acid was injected into the first reactor at a rate of 410 kg / h, nitric acid and silica gel for column chromatography were injected at a rate of 82 kg / h, and ammonia was introduced at a rate of 15 L / h. The reactor temperature was 200℃, and the mixture was held for 2 hours before overflowing into the second reactor.

[0115] The temperature of the second reactor is 230℃. Ammonia gas is introduced at a rate of 13L / h and held for 2 hours. The gas is then overflowed into the third reactor.

[0116] The temperature of the third reactor is 230℃. Ammonia gas is introduced at a rate of 13L / h and held for 2 hours. The gas is then overflowed into the fourth reactor.

[0117] The fourth reactor is heated to 230℃. Ammonia gas is introduced at a rate of 13L / h and held for 2 hours before overflowing into the fifth reactor.

[0118] The fifth reactor is heated to 270℃. Ammonia gas is introduced at a rate of 12L / h, held for 2 hours, and then overflowed into the sixth reactor.

[0119] The temperature of the sixth reactor is 270℃. Ammonia gas is introduced at a rate of 12L / h and held for 2 hours. The gas is then overflowed into the seventh reactor.

[0120] The temperature of the seventh reactor is 270℃. Ammonia gas is introduced at a rate of 12L / h and held for 2 hours. The gas is then overflowed into the eighth reactor.

[0121] The temperature of the eighth reactor is 300℃. Ammonia gas is introduced at a rate of 10L / h and held for 2 hours. The gas is then overflowed into the ninth reactor.

[0122] The temperature of the ninth reactor is 300℃. Ammonia gas is introduced at a rate of 10L / h and held for 2 hours. The gas is then overflowed into the tenth reactor.

[0123] The temperature of the tenth reactor is 300℃. Ammonia gas is introduced at a rate of 10L / h, held for 2 hours, and then overflowed into the eleventh reactor.

[0124] The temperature of the eleventh reactor is 330℃. Ammonia gas is introduced at a rate of 8L / h and held for 2 hours. The gas is then overflowed into the twelfth reactor.

[0125] The temperature of the twelfth reactor is 330℃. Ammonia gas is introduced at a rate of 8L / h and held for 2 hours. The gas is then overflowed into the thirteenth reactor.

[0126] The temperature of the thirteenth reactor is 350℃. Ammonia gas is introduced at a rate of 8L / h and held for 2 hours. The gas is then overflowed into the fourteenth reactor.

[0127] The temperature of the fourteenth reactor is 350℃. Ammonia gas is introduced at a rate of 8L / h and held for 2 hours. The gas is then overflowed into the fifteenth reactor.

[0128] The fifteenth reactor is heated to 400℃. Ammonia gas is introduced at a rate of 7L / h and held for 2 hours before overflowing into the crude nitrile tank.

[0129] After distillation, the forward distillate yielded the target product, sebacate, with a purity of 99.7%, color number 4, and a yield of 98.5%.

[0130] Example 7

[0131] Adopted and Figure 1 A similar apparatus and method were used for the continuous synthesis of sebacic acid from sebacic acid, the only difference being the reactor temperature in each reactor, as detailed below:

[0132] At room temperature and pressure, sebacic acid is injected into the first reactor at a rate of 200 kg / h, nitric acid and silica gel for column chromatography are injected at a rate of 40 kg / h, and ammonia is introduced at a rate of 15 L / h. The reactor temperature is 200℃, and the mixture is held for 2 hours before overflowing into the second reactor.

[0133] The second reactor is heated to 265℃. Ammonia gas is introduced at a rate of 13L / h and held for 2 hours before overflowing into the third reactor.

[0134] The temperature of the third reactor is 295℃. Ammonia gas is introduced at a rate of 12L / h and held for 2 hours. The gas is then overflowed into the fourth reactor.

[0135] The temperature of the fourth reactor is 325℃. Ammonia gas is introduced at a rate of 10L / h, held for 2 hours, and then overflowed into the fifth reactor.

[0136] The fifth reactor is heated to 355℃. Ammonia gas is introduced at a rate of 8L / h, held for 2 hours, and then overflowed into the sixth reactor.

[0137] The temperature of the sixth reactor is 375℃. Ammonia gas is introduced at a rate of 8L / h and held for 2 hours. The gas is then overflowed into the seventh reactor.

[0138] The temperature of the seventh reactor is 395℃. Ammonia gas is introduced at a rate of 7L / h and held for 2 hours before overflowing into the crude nitrile tank.

[0139] After distillation, the forward distillate yielded the target product, sebacate, with a purity of 99.5%, color number 4, and a yield of 98.8%.

[0140] Comparative Example 1

[0141] At ambient temperature and pressure, 2000 kg of sebacic acid, 30 kg of nitric acid, silica gel for column chromatography, and 1500 L of ammonia were injected into a reactor. The reactor temperature was 180°C, and the reaction was carried out for 2 hours. The reactor temperature was then raised to 230°C, and after another 2 hours, it was raised to 270°C. After another 2 hours, the temperature was further raised to 330°C, and the reaction was carried out for 3 hours. Finally, the reactor temperature was raised to 400°C, and the reaction was carried out for 4 hours. The reaction solution was filtered and then distilled in a distillation column. The foredistillate was collected under negative pressure at a column temperature of 150°C, with a top temperature of 145°C. After the foredistillate was collected, the distillation column was heated to 180°C, with a top temperature of 170°C and a reflux ratio of 1:10. The foredistillate was the target product, sebaconitrile, with a purity of 98.7%, color number 10, and a yield of 92.3%.

[0142] While some exemplary embodiments of this application have been described and illustrated, this application is not limited to the disclosed embodiments. Rather, those skilled in the art will recognize that modifications and changes can be made to the described embodiments without departing from the spirit and scope of this application as set forth in the appended claims.

Claims

1. A method for the continuous synthesis of sebacic acid from sebacic acid, comprising carrying out a continuous reaction in n reaction vessels, wherein, The raw materials containing sebacic acid, ammonia and catalyst are fed into the first reactor for reaction, and the product of the (n-1)th reactor is fed into the nth reactor for reaction, where 7≤n≤15; The temperature T1 of the first reactor satisfies 190℃≤T1≤270℃; The temperature of the (n-1)th reactor is T. n-1 The temperature of the nth reactor is T. n Satisfying 0℃≤T n - T n-1 ≤60℃, 350≤T n ≤500℃.

2. The method according to claim 1, characterized in that, 7≤n≤10。 3. The method according to claim 1, characterized in that, The product from the (n-1)th reactor enters the nth reactor via overflow.

4. The method according to claim 1, characterized in that, The temperature T1 of the first reactor satisfies 190℃≤T1≤250℃; and / or The ammonia flow rate in the first reactor is V1, satisfying 5 L / h ≤ V1 ≤ 50 L / h; and / or The temperature of the (n-1)th reactor is T. n-1 The temperature of the nth reactor is T. n Satisfying 5℃≤T n - T n-1 ≤60℃; and / or The ammonia flow rate in the (n-1)th reactor is V. n-1 The ammonia flow rate to the nth reactor is V. n Satisfying 0 L / h ≤ V n-1 - V n ≤ 10L / h.

5. The method according to claim 4, characterized in that, 5L / h≤V1≤30L / h; and / or 0L / h≤V n-1 - V n ≤5L / h.

6. The method according to claim 1, characterized in that, 350≤T n ≤450℃。 7. The method according to claim 4, characterized in that, 2 L / h ≤ V n ≤50L / h.

8. The method according to claim 4, characterized in that, 2 L / h ≤ V n ≤20L / h.

9. The method according to claim 1, characterized in that, The reaction time in each reactor is 2-9 hours.

10. The method according to claim 1, characterized in that, In the raw material containing sebacic acid, ammonia, and catalyst, the molar ratio of sebacic acid to ammonia is in the range of 1:(2-10); and / or The catalyst comprises a mixture of an acidic substance and silica gel, wherein the acidic substance is selected from at least one of sulfuric acid, nitric acid, acetic acid, phosphoric acid, p-toluenesulfonic acid, or acidic resin, and the silica gel is selected from at least one of column chromatography silica gel or thin-film chromatography silica gel.

11. The method according to claim 10, characterized in that, In the catalyst, the mass ratio of acidic substance to silica gel is 1:(0.2-5).

12. The method according to claim 10, characterized in that, In the catalyst, the mass ratio of acidic substance to silica gel is 1:(0.5-3).

13. The method according to claim 1, characterized in that, The dosage rate of sebacic acid is 100 kg / h - 500 kg / h.

14. The method according to claim 1, characterized in that, The dosage rate of sebacic acid is 200 kg / h-400 kg / h.

15. The method according to claim 1, characterized in that, The catalyst is added at a rate of 2 kg / h to 100 kg / h.

16. The method according to claim 1, characterized in that, The catalyst is added at a rate of 5 kg / h to 60 kg / h.

17. The method according to claim 1, characterized in that, The amount of catalyst added is 1%-30% of the mass of sebacic acid.

18. The method according to claim 1, characterized in that, The amount of catalyst added is 2%-20% of the mass of sebacic acid.

19. The method according to claim 1, characterized in that, In the raw material containing sebacic acid, ammonia and catalyst, the molar ratio of sebacic acid to ammonia is in the range of 1:(3.5-5).

20. The method according to claim 1, characterized in that, The method further includes purifying the reaction product of the nth reactor, wherein the purification process includes distilling the reaction product of the nth reactor in a distillation column.

21. The method according to claim 20, characterized in that, The reaction products of the nth reactor include a filtrate that has been cooled and had the catalyst removed.

22. The method according to claim 21, characterized in that, The distillation process includes first distilling the reaction product from the nth reactor in a first distillation column, and then distilling the liquid from the first distillation column in a second distillation column.

23. The method according to claim 22, characterized in that, The bottom temperature of the first distillation column is 120-350℃, and the top temperature is 100-290℃.

24. The method according to claim 22, characterized in that, The bottom temperature of the second distillation column is 130-360℃, and the top temperature is 110-300℃.

25. The method according to claim 22, characterized in that, The pressure of the first distillation column and / or the second distillation column is 1-50 kPa.

26. The method according to claim 22, characterized in that, The reflux ratio of the second distillation column is 1:(1-18).

27. The application of the method according to any one of claims 1-26 in the production of sebacate.

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