The solvent is N, N-isopropyl-Napos; preparation device and preparation method of-phenyl p-phenylenediamine

Abstract

The invention relates to the technical field of organic chemistry, in particular to a preparation device and a preparation method of N-isopropyl-N '-phenyl p-phenylenediamine. The device provided by the invention comprises a reaction unit A and a separation unit B which are sequentially connected, the reaction unit is provided with an acetone and RT base inlet; the reaction unit is sequentially provided with a water absorption unit A-1 filled with a water absorbent and a hydrogenation unit A-2 filled with a noble metal catalyst along the flowing direction of the acetone and RT base mixed solution; the water absorption unit and the hydrogenation unit are arranged in the same reactor. Through the technical scheme, the IPPD preparation device and the preparation method provided by the invention can effectively inhibit side reactions, improve the selectivity of IPPD, simplify the post-treatment purification process and effectively improve the purity of the product, and the purity of the prepared IPPD is greater than 96 wt% and can be greater than 99 wt% at most.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of organic chemistry, and particularly relates to a preparation device and a preparation method of N-isopropyl-N'-phenyl-p-phenylenediamine. BACKGROUND

[0002] N-isopropyl-N'-phenyl-p-phenylenediamine, also known as antioxidant 4010NA or IPPD, as an important p-phenylenediamine antioxidant, has good application value in natural rubber, synthetic rubber and latex fields, and has good effects on preventing ozone aging, metal aging, anti-flexing, fatigue and cracking, and is suitable for industrial rubber products working under static, dynamic or intermittent conditions.

[0003] At present, IPPD is mainly prepared by a reduction hydrocarbon method taking acetone and RT-pest as raw materials, and the reaction mechanism is as shown in the following formula:

[0004]

[0005] In the above reaction process, acetone is prone to a ketone to alcohol side reaction to generate isopropyl alcohol, as shown in the following formula:

[0006]

[0007] Meanwhile, acetone also undergoes self-condensation hydrogenation to generate methyl isobutyl ketone (MIBK), and MIBK further undergoes hydrogenation reaction with RT-pest to generate N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD). In actual industrial production process, the generation of byproduct 6PPD will lead to complex IPPD production process, and special process optimization and separation are required, which affects the quality of IPPD. In the existing preparation process, the reaction conditions are relatively harsh, and since there is no treatment or limitation of acetone before hydrogenation reaction, there is no effective method to control the composition of the product at present.

[0008]

[0009] With the increasing requirements for the quality and diversity of antioxidant products, it is urgent to provide an optimized and improved production process which can realize flexible production according to actual product type requirements and obtain high-purity IPPD. SUMMARY

[0010] In order to overcome the problems in the existing IPPD synthesis process that the side reaction is difficult to control, 6PPD, MIBK and isopropyl alcohol are easily generated, and the product purity of the prepared IPPD needs to be further improved, the present application provides an IPPD preparation device and a preparation method to reduce the generation of byproducts in the IPPD preparation process.

[0011] In order to achieve the above object, the first aspect of the present application provides a preparation device of IPPD, which comprises a reaction unit A and a separation unit B connected in sequence.

[0012] The reaction unit is provided with an inlet of acetone and RT-PEST;

[0013] Along the flow direction of the mixed solution of acetone and RT-PEST, the reaction unit is provided with a water absorption unit A-1 filled with a water absorption agent and a hydrogenation unit A-2 filled with a noble metal catalyst in sequence.

[0014] The water absorption unit and the hydrogenation unit are arranged in the same reactor.

[0015] The second aspect of the present application provides a method for preparing IPPD, which comprises the following steps:

[0016] (1) acetone and RT-PEST are subjected to dehydration condensation in the presence of a water absorption agent to obtain a first mixed solution;

[0017] (2) the first mixed solution is subjected to hydrogenation reaction in the presence of a noble metal catalyst to obtain a second mixed solution;

[0018] (3) the second mixed solution is separated to obtain IPPD and acetone.

[0019] Preferably, the method uses the device provided in the first aspect of the present application.

[0020] Through the above technical solution, first, the raw material acetone is mixed with RT-PEST and then subjected to water absorption by a water absorption agent to promote the dehydration condensation reaction. Then, the hydrogenation reaction is directly carried out in the same reactor in the presence of a noble metal catalyst to obtain a mixed solution containing IPPD. Finally, through separation treatment, high-purity IPPD product is obtained. Compared with the prior art, the IPPD preparation device and method provided by the present application can effectively inhibit the occurrence of side reactions, improve the selectivity of IPPD, simplify the post-treatment purification process, effectively improve the purity of the product, and the prepared IPPD has a purity of greater than 96wt%, and the highest can be greater than 99wt%. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a schematic diagram of the preparation device provided by the present application.

[0022] REFERENCE NUMERALS

[0023] A: reaction unit, A-1: water absorption unit, A-2: hydrogenation unit;

[0024] B: separation unit, B-1: recovery column, B-2: crystallizer. DETAILED DESCRIPTION

[0025] The endpoints of the ranges and any values disclosed herein are not limited to the precise values recited as exactly that endpoint. Any values that fall within the range of values along with the upper and lower limits on the range of values are also considered as being encompassed. For values that are less than or greater than a stated range, or endpoints, or values that are greater than or less than a stated range or endpoints, this is also considered to be encompassed.

[0026] In the present application, the orientation words such as "upper", "lower", "left", "right" are generally referred to the upper, lower, left and right of the corresponding object, unless otherwise stated.

[0027] The first aspect of the present application provides a device for preparing IPPD, which comprises a reaction unit A and a separation unit B connected in sequence.

[0028] The reaction unit is provided with an inlet for acetone and RT-PEST.

[0029] Along the flow direction of the mixture of acetone and RT-PEST, the reaction unit is provided with a water absorption unit A-1 filled with a water absorption agent and a hydrogenation unit A-2 filled with a noble metal catalyst in sequence.

[0030] The water absorption unit and the hydrogenation unit are arranged in the same reactor.

[0031] The present application does not particularly limit the specific composition of the separation unit, which can separate the reaction product. According to a preferred embodiment of the present application, the separation unit comprises a recovery tower B-1 and a crystallizer B-2, and the reaction unit, the recovery tower and the crystallizer are connected in sequence.

[0032] The present application does not particularly limit the relative position of the water absorption unit and the hydrogenation unit. For example, the water absorption unit and the hydrogenation unit can be placed in an up-down manner or in a left-right manner. Since acetone and RT-PEST are liquids at room temperature and normal pressure, and hydrogen is a gas at room temperature and normal pressure, the water absorption unit and the hydrogenation unit are preferably placed in an up-down manner.

[0033] When the water absorption unit and the hydrogenation unit are placed in an up-down manner, according to a preferred embodiment of the present application, the water absorption unit is arranged above the hydrogenation unit, and the gas-liquid countercurrent contact is formed. Preferably, the inlet of the reaction unit for acetone and RT-PEST is arranged above the water absorption unit. Preferably, the inlet of the reaction unit for hydrogen is arranged below the hydrogenation unit. At this time, the outlet of the reaction liquid is arranged below the hydrogenation unit.

[0034] According to another preferred embodiment of the present application, the water absorption unit is arranged below the hydrogenation unit, and the gas and liquid are in counter flow. Preferably, the inlet of the acetone and RT-PEST into the reaction unit is arranged below the water absorption unit. Preferably, the inlet of the hydrogen into the reaction unit is arranged above the water absorption unit and below the hydrogenation unit. In this case, the outlet of the reaction liquid is arranged above the hydrogenation unit.

[0035] According to a specific embodiment of the present application, the acetone and RT-PEST can share one or more inlets, or can have separate inlets.

[0036] According to a preferred embodiment of the present application, the unreacted hydrogen is extracted from the top of the reaction unit and recycled back to the reaction unit.

[0037] The second aspect of the present application provides a method for preparing IPPD, comprising the following steps:

[0038] (1) dehydrating and condensing the acetone and RT-PEST in the presence of a water absorption agent to obtain a first mixed liquid;

[0039] (2) hydrogenating the first mixed liquid in the presence of a noble metal catalyst to obtain a second mixed liquid;

[0040] (3) separating the second mixed liquid to obtain IPPD.

[0041] The present application has a wide range of selection for the water absorption agent. According to a preferred embodiment of the present application, the water absorption agent is activated carbon. The present application also has a wide range of selection for the activated carbon, for example, 4-8 mesh activated carbon can be selected. Preferably, the activated carbon is acidified and oxidized activated carbon.

[0042] For the acid used for acidification, a person skilled in the art can routinely select a common non-oxidizing acid or an oxidizing acid, for example, hydrochloric acid, phosphoric acid, sulfuric acid and nitric acid. According to the present application, the acid used for acidification is preferably hydrochloric acid and / or phosphoric acid.

[0043] For the oxidizing agent used for oxidizing agent activation, a person skilled in the art can routinely select a common oxidizing agent or a solution thereof, for example, hydrogen peroxide, sodium hypochlorite and potassium permanganate or a solution thereof. According to the present application, the oxidizing agent is hydrogen peroxide and sodium hypochlorite solution.

[0044] The inventors of the present application found that acidification and oxidizing agent activation of activated carbon can remove impurities in activated carbon while increasing oxygen-containing groups on the surface of activated carbon, so that activated carbon has better hydrophilicity and stronger water absorption capacity, thereby promoting the dehydrating and condensation reaction of acetone and RT-PEST, facilitating the generation of intermediate Schiff base, and removing the water content in the reaction. Therefore, the generation of isopropyl alcohol and MIBK can be effectively controlled, thereby inhibiting the generation of 6PPD.

[0045] The present application has a wide range of selection for the noble metal catalyst in step (2), and the person skilled in the art can select the conventional catalyst for preparing IPPD. According to the present application, preferably, the noble metal catalyst is a supported catalyst, and the carrier is selected from at least one of coconut shell activated carbon, molecular sieve and silicon dioxide, preferably coconut shell activated carbon. More preferably, the specific surface area of the coconut shell activated carbon carrier is 900-1200 m 2 / g, the pore volume is 0.5-2.5 g / ml, the pore size is 1.0-2.5 nm, the ash content is less than 5%, and the water absorption is greater than 60%. Preferably, the active component can be selected from at least one of Pt, Pd and Ni, more preferably Pt. Preferably, the mass ratio of the active component to the carrier is 0.1-1:100.

[0046] The present application has a wide range of selection for the amount of water absorbing agent and catalyst, and the person skilled in the art can select conventionally. According to the present application, preferably, the volume ratio of the water absorbing agent to the noble metal catalyst is 1:0.5-1.5, more preferably 1:1-1.5.

[0047] The present application has a wide range of selection for the amount of raw material, and the person skilled in the art can select conventionally. According to the present application, preferably, the volume ratio of acetone to RT-PEST is 1-2:1. Preferably, the volume space velocity of the acetone and RT-PEST mixture is 0.15-0.4 h -1 / 100 ml of the total volume of the water absorbing agent and the noble metal catalyst.

[0048] The present application has a wide range of selection for the temperature and pressure of the dehydration condensation reaction, and the person skilled in the art can select conventionally. According to the present application, preferably, in step (1), the pressure is 0.5-1.5 MPa, more preferably 0.8-1.2 MPa; the temperature is 40-120℃, more preferably 50-70℃.

[0049] The present application has a wide range of selection for the temperature and pressure of the hydrogenation reaction, and the person skilled in the art can select conventionally. According to the present application, preferably, in step (2), the pressure is 0.5-1.5 MPa, more preferably 0.8-1.2 MPa; the temperature is 40-120℃, more preferably 50-70℃.

[0050] According to a preferred embodiment of the present application, step (3) comprises the following steps:

[0051] (3-1) rectifying the second mixture to recover acetone and obtain a third mixture;

[0052] (3-2) crystallizing the third mixture to obtain IPPD.

[0053] According to a preferred embodiment of the present application, the acetone recovered in step (3-1) is recycled to step (1).

[0054] The present application has a wide range of selection for the specific operation conditions of the rectification, and can achieve the separation purpose. According to a preferred embodiment of the present application, in step (3-1), the overhead temperature is 50-60℃, and the bottom temperature is 90-100℃. Preferably, the reflux ratio is 4-5.

[0055] According to the present application, preferably, the content of acetone in the third mixed solution is less than 15wt%. The inventors of the present application have found that when the content of acetone in the third mixed solution is low, it is beneficial to crystallize to obtain high-purity IPPD product.

[0056] The present application has a wide range of selection for the specific operation conditions of the crystallization, and can achieve the separation purpose. According to the present application, preferably, the temperature of the crystallization in step (3-2) is 50-60℃.

[0057] According to a preferred embodiment of the present application, the above method uses the device provided by the first aspect of the present application.

[0058] According to a preferred embodiment of the present application, the device as described above is used. Figure 1

[0059] Preferably, the remaining hydrogen gas in the reaction unit is extracted from the top of the reaction unit and recycled for hydrogenation.

[0060] The present application will be described in detail below through examples.

[0061] In the following examples, the composition of the overhead and bottom discharges of the recovery column and the purity of the IPPD product are measured by gas chromatograph Agilent 7890A, according to GB / T 8828-2003;

[0062] The noble metal catalyst is purchased from Shanghai Aladdin Biochem Technology Co., Ltd.;

[0063] The other reagents and raw materials are all commercially available.

[0064] Preparation Example 1

[0065] The activated carbon is immersed in 10wt% hydrochloric acid, stirred in a constant temperature water bath at 50℃ for 2h, filtered, washed with water, and then immersed in 3wt% hydrogen peroxide and 0.5wt% sodium hypochlorite aqueous solution at 20℃ for 4h, washed and dried to obtain acidified and activated activated carbon.

[0066] Preparation Example 2

[0067] ​The activated carbon was immersed in 12wt% phosphoric acid, stirred in a constant temperature water bath at 50℃ for 2h, filtered, washed with water, and then immersed in 3wt% hydrogen peroxide and 0.5wt% sodium hypochlorite aqueous solution at 20℃ for 4h. After washing and drying, the acidified and activated activated carbon was obtained.

[0068] Example 1

[0069] The preparation device as shown in Figure 1 was used to prepare IPPD, and the volume ratio of water absorption agent to noble metal catalyst was 1:1. Acetone and RT perst were mixed in a volume ratio of 1.5:1, and the mixture of acetone and RT perst was mixed with hydrogen at a total volume space velocity of 0.25h -1 into reaction unit A, first into water absorption unit A-1 filled with water absorption agent, which is the activated carbon obtained in Preparation Example 1, and then directly into hydrogenation unit A-2 mixed with hydrogen, and hydrogenation unit A-2 is filled with noble metal catalyst (the mass of Pt is 0.30% of the total mass of noble metal catalyst), and hydrogenation reaction is carried out (the pressure is 1.0MPa, the temperature is 60℃, and the volume ratio of hydrogen to the mixture of acetone and RT perst is 200:1), to obtain a second mixture; the second mixture enters separation unit B, first into recovery column B-1 (the top temperature is 50℃, the bottom temperature is 100℃, and the reflux ratio is 4.5) for rectification, and separates out acetone from the top of the column to return to reaction unit A to continue to participate in the reaction, and a third mixture (in which the total content of acetone, isopropyl alcohol and MIBK is 10.5wt%) is obtained at the bottom of the recovery column; the third mixture enters crystallizer B-2 (the crystallization temperature is 60℃) for crystallization, and IPPD product is separated and obtained.

[0070] The content of by-products in the obtained second mixture and the purity of IPPD product obtained by crystallization are shown in Table 1.

[0071] Comparative Example

[0072] The preparation device as shown in Figure 1 was used to prepare IPPD, except that the device did not contain water absorption unit A-1. Acetone and RT perst were mixed in a volume ratio of 1.5:1, and the mixture of acetone and RT perst was mixed with hydrogen at a total volume space velocity of 0.25h -1The second mixture liquid enters separation unit B, and enters recovery column B-1 (the top temperature of the column is 50°C, the bottom temperature of the column is 100°C, and the reflux ratio is 4.5) to be rectified, and acetone is separated out from the top of the column to return to the dehydration and condensation unit A to continue to participate in the reaction, and a third mixture liquid (in which the total content of acetone, isopropyl alcohol and MIBK is 15.5 wt%) is obtained at the bottom of the column; the third mixture liquid enters crystallizer B-2 (the crystallization temperature is 60°C) to be crystallized, and the IPPD product is separated out.

[0073] The content of by-products in the obtained second mixture liquid and the purity of the IPPD product obtained by crystallization are shown in Table 1.

[0074] Example 2

[0075] The IPPD is prepared using the preparation device as shown in Figure 1 The volume ratio of the water absorbent to the noble metal catalyst is 1:1. Acetone and RT pei are mixed at a volume ratio of 1.5:1, and the mixture of acetone and RT pei is fed into the reaction unit A at a total volume space velocity of 0.25 h -1 The second mixture liquid enters separation unit B, and enters recovery column B-1 (the top temperature of the column is 50°C, the bottom temperature of the column is 100°C, and the reflux ratio is 4) to be rectified, and acetone is separated out from the top of the column to return to the reaction unit A to continue to participate in the reaction, and a third mixture liquid (in which the total content of acetone, isopropyl alcohol and MIBK is 12.6 wt%) is obtained at the bottom of the column; the third mixture liquid enters crystallizer B-2 (the crystallization temperature is 60°C) to be crystallized, and the IPPD product is separated out.

[0076] The content of by-products in the obtained second mixture liquid and the purity of the IPPD product obtained by crystallization are shown in Table 1.

[0077] Example 3

[0078] The IPPD is prepared using the preparation device as shown in Figure 1The apparatus shown is used to prepare IPPD, with a volume ratio of desiccant to noble metal catalyst of 1:0.5. Acetone and RT-peptide are mixed at a volume ratio of 1.5:1, and the mixture is prepared at a total volume hourly space velocity (TVHSV) of 0.25 h⁻¹. -1 The mixture enters reaction unit A and first enters water absorption unit A-1, which is filled with a desiccant, namely the activated carbon obtained in Preparation Example 1. It then directly enters hydrogenation unit A-2, where it mixes with hydrogen and undergoes a hydrogenation reaction under the action of a noble metal catalyst (Pt mass is 1.0% of the total catalyst) (pressure 1.0 MPa, temperature 60°C, volume ratio of hydrogen to acetone to RT-Purpose mixture is 200:1), yielding a second mixture. This second mixture enters separation unit B and first enters recovery tower B-1 (top temperature 50°C, bottom temperature 100°C, reflux ratio 4.5) for distillation. Acetone is separated and returned from the top of the tower to reaction unit A to continue participating in the reaction. A third mixture (containing acetone, isopropanol, and MIBK totaling 12.5 wt%) is obtained at the bottom of the recovery tower. This third mixture enters crystallizer B-2 (crystallization temperature 60°C) for crystallization, separating to obtain the IPPD product.

[0079] The content of byproducts in the second mixture and the purity of the IPPD product obtained by crystallization are shown in Table 1.

[0080] Example 4

[0081] Use such as Figure 1 The apparatus shown is used to prepare IPPD, with a volume ratio of desiccant to noble metal catalyst of 1:1. Acetone and RT-peptide are mixed at a volume ratio of 2:1, and the mixture is prepared at a total volume hourly space velocity (TVHSV) of 0.25 h⁻¹. -1 The mixture enters reaction unit A and first enters water absorption unit A-1, which is filled with a desiccant, namely activated carbon. It then directly enters hydrogenation unit A-2, where it mixes with hydrogen and undergoes a hydrogenation reaction under the action of a noble metal catalyst (Pt mass is 0.30% of the total catalyst) (pressure 1.0 MPa, temperature 60°C, volume ratio of hydrogen to acetone to RT-based mixture 100:1), yielding a second mixture. This second mixture enters separation unit B and first enters recovery tower B-1 (top temperature 50°C, bottom temperature 100°C, reflux ratio 4.5) for distillation. Acetone is separated and returned from the top of the tower to reaction unit A to continue participating in the reaction. A third mixture (containing acetone, isopropanol, and MIBK totaling 12.8 wt%) is obtained at the bottom of the recovery tower. This third mixture enters crystallizer B-2 (crystallization temperature 60°C) for crystallization, separating to obtain the IPPD product.

[0082] The byproduct content in the second mixture and the purity of the IPPD product obtained by crystallization are shown in Table 1.

[0083] Example 5

[0084] The IPPD was prepared using the preparation device as shown in Figure 1 The volume ratio of the water absorption agent to the noble metal catalyst was 1:1. Acetone and RTPE were mixed at a volume ratio of 0.5:1, and the mixture of acetone and RTPE was fed into the reaction unit A at a total volume space velocity of 0.25 h -1 The second mixture entered the reaction unit A, first entered the water absorption unit A-1, which was filled with the water absorption agent, i.e. the activated carbon obtained in Preparation Example 2, and then directly entered the hydrogenation unit A-2, mixed with hydrogen, and reacted under the action of the noble metal catalyst (the mass of Pt was 0.30% of the total amount of the catalyst) (the pressure was 1.0 MPa, the temperature was 60°C, and the volume ratio of hydrogen to the mixture of acetone and RTPE was 200:1) to obtain a second mixture; the second mixture entered the separation unit B, first entered the recovery column B-1 (the top temperature was 50°C, the bottom temperature was 100°C, and the reflux ratio was 4.5) for rectification, and separated out acetone from the top of the column to return to the reaction unit A to continue to participate in the reaction, and obtained a third mixture at the bottom of the recovery column (in which the total content of acetone, isopropyl alcohol and MIBK was 9.7wt%); the third mixture entered the crystallizer B-2 (the crystallization temperature was 60°C) for crystallization, and separated to obtain an IPPD product.

[0085] The byproduct content in the second mixture and the purity of the IPPD product obtained by crystallization are shown in Table 1.

[0086] Example 6

[0087] The IPPD was prepared using the preparation device as shown in Figure 1 The volume ratio of the water absorption agent to the noble metal catalyst was 1:1. Acetone and RTPE were mixed at a volume ratio of 0.5:1, and the mixture of acetone and RTPE was fed into the reaction unit A at a total volume space velocity of 0.25 h -1The mixture enters reaction unit A and first enters water absorption unit A-1, which is filled with a desiccant, namely the activated carbon obtained in Preparation Example 1. It then directly enters hydrogenation unit A-2, where it mixes with hydrogen and undergoes a hydrogenation reaction under the action of a noble metal catalyst (Pt mass is 0.30% of the total catalyst) (pressure 1.0 MPa, temperature 60°C, volume ratio of hydrogen to acetone to RT-Purpose mixture 200:1), yielding a second mixture. This second mixture enters separation unit B and first enters recovery tower B-1 (top temperature 50°C, bottom temperature 100°C, reflux ratio 4.5) for distillation. Acetone is separated and returned from the top of the tower to reaction unit A to continue participating in the reaction. A third mixture (where the sum of acetone, isopropanol, and MIBK content is 10.2 wt%) is obtained at the bottom of the recovery tower. This third mixture enters crystallizer B-2 (crystallization temperature 60°C) for crystallization, separating to obtain the IPPD product.

[0088] The content of byproducts in the second mixture and the purity of the IPPD product obtained by crystallization are shown in Table 1.

[0089] Example 7

[0090] Use such as Figure 1 The apparatus shown is used to prepare IPPD, with a volume ratio of desiccant to noble metal catalyst of 1:1. Acetone and RT-peptide are mixed at a volume ratio of 1.5:1, and the mixture is prepared at a total volume hourly space velocity (TVHSV) of 0.15 h⁻¹. -1 The mixture enters reaction unit A and first enters water absorption unit A-1, which is filled with a desiccant, namely the activated carbon obtained in Preparation Example 2. It then directly enters hydrogenation unit A-2, where it mixes with hydrogen and undergoes a hydrogenation reaction under the action of a noble metal catalyst (Pt mass is 0.30% of the total catalyst) (pressure 1.0 MPa, temperature 60°C, volume ratio of hydrogen to acetone to RT-Purpose mixture 200:1), yielding a second mixture. This second mixture enters separation unit B and first enters recovery tower B-1 (top temperature 50°C, bottom temperature 100°C, reflux ratio 4.5) for distillation. Acetone is separated and returned from the top of the tower to reaction unit A to continue participating in the reaction. A third mixture (wherein the sum of acetone, isopropanol, and MIBK content is 9.6 wt%) is obtained at the bottom of the recovery tower. This third mixture enters crystallizer B-2 (crystallization temperature 60°C) for crystallization, separating to obtain the IPPD product.

[0091] The content of byproducts in the second mixture and the purity of the IPPD product obtained by crystallization are shown in Table 1.

[0092] Example 8

[0093] Use such as Figure 1The apparatus shown is used to prepare IPPD, with a volume ratio of desiccant to noble metal catalyst of 1:1. Acetone and RT-peptide are mixed at a volume ratio of 1.5:1, and the mixture is prepared at a total volume hourly space velocity (TVHSV) of 0.25 h⁻¹. -1 The mixture enters reaction unit A and first enters water absorption unit A-1, which is filled with a desiccant, namely the activated carbon obtained in Preparation Example 2. It then directly enters hydrogenation unit A-2, where it mixes with hydrogen and undergoes a hydrogenation reaction under the action of a noble metal catalyst (Pt mass is 0.30% of the total catalyst) (pressure 0.8 MPa, temperature 60°C, volume ratio of hydrogen to acetone to RT-Purpose mixture is 200:1), yielding a second mixture. This second mixture enters separation unit B and first enters recovery tower B-1 (top temperature 50°C, bottom temperature 100°C, reflux ratio 4) for distillation. Acetone is separated and returned from the top of the tower to reaction unit A to continue participating in the reaction. A third mixture (where the sum of acetone, isopropanol, and MIBK content is 12.2 wt%) is obtained at the bottom of the recovery tower. This third mixture enters crystallizer B-2 (crystallization temperature 60°C) for crystallization, separating to obtain the IPPD product.

[0094] The content of byproducts in the second mixture and the purity of the IPPD product obtained by crystallization are shown in Table 1.

[0095] Example 9

[0096] Use such as Figure 1 The apparatus shown is used to prepare IPPD, with a volume ratio of desiccant to noble metal catalyst of 1:1. Acetone and RT-peptide are mixed at a volume ratio of 1.5:1, and the mixture is prepared at a total volume hourly space velocity (VHSV) of 0.25 h⁻¹. 1 The mixture enters reaction unit A and first enters water absorption unit A-1, which is filled with a desiccant, namely the activated carbon obtained in Preparation Example 1. It then directly enters hydrogenation unit A-2, where it mixes with hydrogen and undergoes a hydrogenation reaction under the action of a noble metal catalyst (Pt mass is 0.30% of the total catalyst) (pressure 1.2 MPa, temperature 60°C, volume ratio of hydrogen to acetone to RT-based mixture 200:1), yielding a second mixture. This second mixture enters separation unit B and first enters recovery tower B-1 (top temperature 50°C, bottom temperature 100°C, reflux ratio 4.5) for distillation. Acetone is separated and returned from the top of the tower to reaction unit A to continue participating in the reaction. A third mixture (containing acetone, isopropanol, and MIBK totaling 13.6 wt%) is obtained at the bottom of the recovery tower. This third mixture enters crystallizer B-2 (crystallization temperature 60°C) for crystallization, separating to obtain the IPPD product.

[0097] The content of byproducts in the second mixture and the purity of the IPPD product obtained by crystallization are shown in Table 1.

[0098] Example 10

[0099] Use such as Figure 1 The apparatus shown is used to prepare IPPD, with a volume ratio of desiccant to noble metal catalyst of 1:1. Acetone and RT-peptide are mixed at a volume ratio of 1.5:1, and the mixture is prepared at a total volume hourly space velocity (GBHV) of 0.25 h⁻¹. -1 The mixture enters reaction unit A and first enters water absorption unit A-1, which is filled with a desiccant, namely the activated carbon obtained in Preparation Example 1. It then directly enters hydrogenation unit A-2, where it mixes with hydrogen and undergoes a hydrogenation reaction under the action of a noble metal catalyst (Pt mass is 0.30% of the total catalyst) (pressure 1.0 MPa, temperature 50°C, volume ratio of hydrogen to acetone to RT-Purpose mixture 200:1), yielding a second mixture. This second mixture enters separation unit B and first enters recovery tower B-1 (top temperature 50°C, bottom temperature 100°C, reflux ratio 4.5) for distillation. Acetone is separated and returned from the top of the tower to reaction unit A to continue participating in the reaction. A third mixture (containing acetone, isopropanol, and MIBK totaling 9.8 wt%) is obtained at the bottom of the recovery tower. This third mixture enters crystallizer B-2 (crystallization temperature 60°C) for crystallization, separating to obtain the IPPD product.

[0100] The content of byproducts in the second mixture and the purity of the IPPD product obtained by crystallization are shown in Table 1.

[0101] Example 11

[0102] Use such as Figure 1 The apparatus shown is used to prepare IPPD, with a volume ratio of desiccant to noble metal catalyst of 1:1.5. Acetone and RT-peptide are mixed at a volume ratio of 1.5:1, and the mixture is prepared at a total volume hourly space velocity (TVHSV) of 0.25 h⁻¹. -1Into the reaction unit A, first into the activated carbon water absorption unit A-1, which is filled with water absorption agent, the water absorption agent is activated carbon obtained in Preparation Example 1; then directly into the hydrogenation unit A-2, mixed with hydrogen, and hydrogenation reaction is carried out under the action of noble metal catalyst (the mass of Pt is 0.30% of the total amount of catalyst), the pressure is 1.0 MPa, the temperature is 70℃, the volume ratio of hydrogen to acetone to RT peris mixture is 400:1, to obtain the second mixture; the second mixture enters the separation unit B, first into the recovery column B-1 (the top temperature is 50℃, the bottom temperature is 100℃, the reflux ratio is 5) for rectification, and the acetone is separated out from the top of the column to return to the reaction unit A to continue to participate in the reaction, and the third mixture is obtained at the bottom of the recovery column (in which the content of acetone, isopropanol and MIBK is 12.4wt%); the third mixture enters the crystallizer B-2 (the crystallization temperature is 60℃) for crystallization, and the IPPD product is separated and obtained.

[0103] The content of by-products in the obtained second mixture and the purity of the IPPD product obtained by crystallization are shown in Table 1.

[0104] Table 1

[0105]

[0106] As can be seen from the results of the above examples and comparative examples, using the process for preparing IIPD of the present application, high-purity IPPD product can be prepared after one-step continuous reaction of dehydration condensation and hydrogenation, and the performance of side reactions can be effectively inhibited, the generation of various by-products in the reaction process is reduced, and high-purity IPPD product is obtained.

[0107] The above describes the preferred embodiments of the present application in detail, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be considered as disclosed by the present application, and all fall within the protection scope of the present application.

Claims

1. An apparatus for preparing N-isopropyl-N'-phenyl-p-phenylenediamine, characterized in that, The device includes a reaction unit (A) and a separation unit (B) connected in sequence; The reaction unit is equipped with inlets for acetone and RT-pressed protein. Along the flow direction of the acetone and RT mixture, the reaction unit is sequentially provided with a water-absorbing unit (A-1) filled with a water-absorbing agent and a hydrogenation unit (A-2) filled with a noble metal catalyst; The water absorption unit and the hydrogenation unit are located in the same reactor.

2. The apparatus according to claim 1, wherein, The separation unit includes a recovery tower (B-1) and a crystallizer (B-2), and the reaction unit, recovery tower and crystallizer are connected in sequence.

3. The apparatus according to claim 1 or 2, wherein, The water absorption unit is located below the hydrogenation unit; Preferably, the reaction unit is further provided with inlets for acetone and RT-peptide, which are located below the water absorption unit.

4. The apparatus according to claim 3, wherein, The reaction unit is also provided with a hydrogen inlet, which is located above the water absorption unit and below the hydrogenation unit.

5. A method for preparing N-isopropyl-N'-phenyl-p-phenylenediamine, characterized in that, Includes the following steps: (1) In the presence of a dehydrating agent, acetone and RT-Plast are dehydrated and condensed to obtain a first mixture; (2) The first mixture is hydrogenated in the presence of a noble metal catalyst to obtain the second mixture; (3) Separate the second mixture to obtain N-isopropyl-N'-phenyl-p-phenylenediamine and acetone.

6. The method according to claim 5, wherein, The absorbent is activated carbon; Preferably, the activated carbon is activated carbon that has been acidified and activated by an oxidant.

7. The method according to claim 5 or 6, wherein, The volume ratio of water-absorbing agent to precious metal catalyst is 1:0.5-1.5; Preferably, the volume ratio of acetone to RT-peptide is 1-2:1; Preferably, based on the total volume of the desiccant and the noble metal catalyst, the volume hourly space velocity (VHSV) of the acetone-RT-p-ester mixture is 0.15-0.4 h⁻¹. -1 ; Preferably, the volume ratio of hydrogen to acetone to RT-peptide mixture is 100-400:

1.

8. The method according to any one of claims 5-7, wherein, In step (1), the pressure is 0.5-1.5 MPa, preferably 0.8-1.2 MPa; the temperature is 40-120℃, preferably 50-70℃; Preferably, in step (2), the pressure is 0.5-1.5 MPa, more preferably 0.8-1.2 MPa; the temperature is 40-120℃, more preferably 50-70℃.

9. The method according to any one of claims 5-8, wherein, Step (3) includes the following steps: (3-1) The second mixture is distilled to recover acetone and obtain the third mixture; (3-2) Crystallize the third mixture to obtain N-isopropyl-N'-phenyl-p-phenylenediamine; Preferably, the acetone recovered in step (3-1) is returned to step (1) for recycling.

10. The method according to claim 9, wherein, In step (3-1), the temperature at the top of the tower is 50-60℃, and the temperature at the bottom of the tower is 90-100℃; Preferably, the reflux ratio is 4-5; Preferably, the acetone content in the third mixture is less than 15 wt%.

11. The method according to claim 9 or 10, wherein, The crystallization temperature in step (3-2) is 50-60℃.

12. The method according to any one of claims 5-11, wherein, The method uses the apparatus described in any one of claims 1-4.

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