WO2016058207A1 - Preparation method for 3-aminomethyl-3,5,5-trimethyl cyclohexylamine - Google Patents

Abstract

Provided is a preparation method for 3-aminomethyl-3,5,5-trimethyl cyclohexylamine. The method comprises: a) controlling the acid number of 3-cyano-3,5,5-trimethyl cyclohexanone at 0.02 - 0.50 mg KOH/g, reacting with liquid ammonia to obtain a partially imidized reaction liquid; b) adding an alkaline acid number regulator into the partially imidized reaction liquid obtained in step a) with an adding amount of 0.2-5‰ of the molar weight of the 3-cyano-3,5,5-trimethyl cyclohexanone to continue an imidization reaction; and c) hydrogenating the product obtained in step b) in the presence of hydrogen, liquid ammonia and a catalyst to produce 3-aminomethyl-3,5,5-trimethyl cyclohexylamine. The preparation method has a yield of 3-aminomethyl-3,5,5-trimethyl cyclohexylamine close to 99%, and has an increased space velocity, an increased reaction efficiency, thus saving the costs of catalyst and equipment.

Description

Preparation method of 3-aminomethyl-3,5,5-trimethylcyclohexylamine Technical field

The invention relates to a method for preparing an aliphatic diamine, in particular to a method for preparing 3-aminomethyl-3,5,5-trimethylcyclohexylamine.

Background technique

3-aminomethyl-3,5,5-trimethylcyclohexylamine (also known as isophoronediamine, abbreviated as IPDA) is a 3-isocyanate-methylene-3,5,5-trimethyl group. A raw material such as cyclohexyl isocyanate (also known as isophorone diisocyanate, abbreviated as IPDI) or polyamide can also be used as a curing agent for an epoxy resin.

At the current industrial scale, the mainstream preparation method of IPDA usually includes an imidization step and a hydrogenation step, first through 3-cyano-3,5,5-trimethylcyclohexanone (also known as isophorone nitrile, Acronym IPN) reacts with liquid ammonia to form 3-cyano-3,5,5-trimethylcyclohexylimine (also known as isophorone nitrile imine, IPNI for short), followed by the presence of IPNI and hydrogen in liquid ammonia. The reductive amination reaction is carried out catalytically to obtain IPDA. The imidization step and the hydrogenation step for the preparation of IPDA from IPN are usually carried out in two or three separate reactors, and are also reported in the literature to be completed in one reactor.

There are numerous parallel side reactions in the preparation of IPDA by IPN amination hydrogenation, for example: direct hydrogenation of IPN to form amino alcohol (IPAA), which is caused by insufficient imidization of IPN; formation of secondary amines, which are derived from nitrogen atoms. It is determined by the electronegativity difference and molecular structure of carbon atoms; the formation of bis-IPDA precursors is also determined by the electronegativity difference of carbon and nitrogen atoms.

In Chinese patent document CN101386579A, IPDA, liquid ammonia, solvent, catalyst and cocatalyst are produced in one reactor at 50-120 ° C and 5-15 MPa hydrogen pressure in a one-step process. This method inevitably produces a large amount of decyanolated products (a), (b) and amino alcohols (c), thereby limiting the yield of IPDA.

German Patent Publication No. DE 10 142 635 A1 discloses a three-step process for the preparation of IPDA comprising an imidization step and two hydrogenation steps, wherein the imidization step is carried out by IPN with excess liquid ammonia at 20-150 ° C and 50-300 The reaction under the pressure of Ba produces 3-cyano-3,5,5-trimethylcyclohexanoneimine (IPNI), optionally on an acidic metal oxide catalyst. The disadvantage of this method is that the amount of amino alcohol (c), secondary amine (d) and bis-IPDA (e) is large, which limits the yield of IPDA.

The following figure shows the side reaction history of IPDA prepared by IPN amination hydrogenation.

Over the years, the research on the preparation of IPDA by IPN amination hydrogenation has focused on the hydrogenation step. From the patent reports in recent years, the yield and selectivity of the IPDA reaction prepared by IPN have reached a high level. The imidization step is a reversible reaction, and the means for generally adjusting the imidization reaction rate is achieved by adjusting the reaction temperature and the use of the catalyst, but the effect is not significant. In the above patent documents and the reported preparation method of IPDA, the space velocity of the imidization step is usually only 0.5-20 g IPN/(ml catalyst·hour) due to the imidization reaction rate, and the space velocity is not high, resulting in a reaction site. The amount of catalyst required is large, the equipment is bulky, and the cost is high.

In summary, the existing IPDA preparation process cannot overcome the defects of many by-products and low space velocity in the imidization step, so it is necessary to seek a new IPDA preparation process to overcome the above technical defects.

Summary of the invention

The object of the present invention is to provide a preparation method of 3-aminomethyl-3,5,5-trimethylcyclohexylamine (IPDA), which can effectively reduce secondary products such as secondary amines, amino alcohols and bis-IPDA. The production yields higher yields, and the method can also significantly increase the imidization rate of IPN, thereby greatly increasing the reaction space velocity and reducing the basic investment of equipment.

In order to achieve the above object, the technical solution of the present invention is as follows:

A method for preparing 3-aminomethyl-3,5,5-trimethylcyclohexylamine (IPDA), the method comprising the steps of:

a) controlling the acid value of the raw material 3-cyano-3,5,5-trimethylcyclohexanone (IPN) at 0.02 to 0.50 mgKOH/g, preferably 0.05 to 0.30 mgKOH/g, and in liquid ammonia The reaction is carried out in a hydrogen atmosphere or in a hydrogen-free atmosphere to obtain a partially imidized reaction solution;

b) adding a basic acid value adjuster to the partially imidized reaction liquid obtained in the step a) in an amount of 0.2 to 5 Torr, preferably 0.5 to 3 Torr, in a hydrogen atmosphere. Or continue the imidization reaction without hydrogen atmosphere;

c) Hydrogenating the product obtained in step b) in the presence of hydrogen, liquid ammonia and a catalyst to form IPDA.

IPN materials are usually acidic. It is well known to those skilled in the art that under alkaline conditions, IPN readily deacylates to form an undesired de-cyano product, and IPN acidity is advantageous for reducing the production of de-cyano products, and thus imidization is generally not considered in the art. The acid value of the IPN material is adjusted in the step.

However, when the raw material IPN is more acidic, the imidization step will generate more bis-IPDA precursors, while the imidization reaction rate is not high and the space velocity is low; while the raw material IPN is alkaline, although it will decrease The formation of the bis-IPDA precursor in the imidization step is reduced, but the IPN undergoes a large number of decyanolation reactions during the reaction, thereby reducing the reaction yield of the IPDA.

The inventors have found that when the raw material IPN has an appropriate acid value level, it helps to accelerate the imidization reaction rate of IPN and reduce the amount of IPAA produced in the hydrogenation process; and after the IPN imidization reaction proceeds to a certain extent, Adding a certain amount of basic acid value regulator can effectively inhibit the nucleophilic reaction rate of nitrogen atoms and carbon atoms, thereby inhibiting the formation of secondary amine groups and bis-IPDA precursors, thereby reducing amino alcohols and secondary amines in the hydrogenation step. And the content of double-IPDA. Literature research shows that the relationship between the imidization reaction rate and the acid value of the system has not been reported.

Therefore, the process of the present invention divides the reaction into three steps, namely two imidization steps a) and b) and one hydrogenation step c), first controlling the acid value of the raw material IPN within a certain range, but still being acidic, After the imidization reaction is carried out to a certain extent, a certain amount of basic acid value is added to the reaction solution. The agent makes the IPN extremely weakly acidic or slightly alkaline. This not only ensures that no excessive de-cyano product is produced, but also the content of the bis-IPDA precursor in the imidization step is well controlled, and the reaction rate of the imidization reaction is greatly improved. Intermediate secondary amines, amino alcohols, and bis-IPDA production were all significantly inhibited.

Preferably, in step a), the IPN is reacted with liquid ammonia to an IPN conversion of 50 to 80%, preferably 60 to 70%, to obtain the partially imidized reaction liquid. The inventors have found that when step a) is reacted to the conversion, the addition of a basic acid number modifier is more advantageous for reducing the formation of the denitrile product, the amino alcohol and the bis-IPDA precursor.

In the method of the present invention, the acid value of the raw material IPN of the step a) can be adjusted according to the quality of the raw material, by adding an acidic compound or a basic compound.

Preferably, the acidic compound is selected from an organic acid or a mineral acid which does not have strong oxidizing property and strong corrosivity, and preferably one or more of phosphoric acid, acetic acid, boric acid, oxalic acid, benzoic acid and carbonic acid, more preferably It is phosphoric acid and/or acetic acid.

Preferably, the basic compound is selected from the group consisting of oxides, hydroxides or carbonates of alkali metals, oxides, hydroxides or carbonates of alkaline earth metals, or oxides, hydroxides or carbons of rare earth metals One or more of the acid salts, preferably one or more of an oxide, hydroxide or carbonate of an alkali metal, or an oxide, hydroxide or carbonate of an alkaline earth metal, more preferably Li ₂ O, Na ₂ O, K ₂ O, Rb ₂ O, Cs ₂ O, LiOH, NaOH, KOH, RbOH, CsOH, Li ₂ CO ₃ , Na ₂ CO ₃ , K ₂ CO ₃ , Rb ₂ CO ₃ One or more of MgO, CaO, SrO, BaO, Mg(OH) ₂ , Ca(OH) ₂ , Sr(OH) ₂ , Ba(OH) ₂ , MgCO ₃ , CaCO ₃ , SrCO ₃ or BaCO ₃ Particularly preferred are LiOH and/or NaOH.

In the method of the present invention, preferably, step a) is carried out at a temperature of from 30 to 100 ° C and a pressure of from 0.5 to 30 MPa, more preferably at a temperature of from 40 to 60 ° C and a pressure of from 15 to 20 MPa.

According to the process of the present invention, preferably, the alkaline acid number adjusting agent involved in step b) is selected from the group consisting of oxides, hydroxides or carbonates of alkali metals, oxides, hydroxides or carbonates of alkaline earth metals. a salt, or one or more of an oxide, hydroxide or carbonate of a rare earth metal, more preferably an oxide, hydroxide or carbonate of an alkali metal, or an oxide or hydroxide of an alkaline earth metal. One or more of the substances or carbonates, more preferably Li ₂ O, Na ₂ O, K ₂ O, Rb ₂ O, Cs ₂ O, LiOH, NaOH, KOH, RbOH, CsOH, Li ₂ CO ₃ , Na ₂ CO ₃ , K ₂ CO ₃ , Rb ₂ CO ₃ , MgO, CaO, SrO, BaO, Mg(OH) ₂ , Ca(OH) ₂ , Sr(OH) ₂ , Ba(OH) ₂ , MgCO ₃ One or more of CaCO ₃ , SrCO ₃ or BaCO ₃ is particularly preferably LiOH and/or NaOH.

In the method of the present invention, preferably, step b) is at a temperature of 20 to 80 ° C and a pressure of 0.5 to 30 MPa. It is more preferably carried out at a temperature of 20 to 40 ° C and a pressure of 15 to 20 MPa.

According to the process of the present invention, the IPN in steps a) and b) is imidized with liquid ammonia, and the reaction may be carried out using a catalyst or not using a catalyst, preferably a catalyst. The catalyst may be any useful imidization catalyst, such as an acidic metal oxide, an acidic ion exchange resin, a heteropolyacid, a sulfonic acid group-containing organopolysiloxane or activated carbon.

Preferably, step a) uses an acidic metal oxide, more preferably gamma-alumina is used as a catalyst.

Preferably, step b) uses activated carbon as the catalyst.

In steps a) and b), a higher imidization reaction rate can be obtained by controlling the acid value of the raw material IPN and adding a basic acid value regulator during the imidization reaction. The IPN conversion rate described in step a) can be controlled by adjusting the airspeed. The space velocity can be controlled by adjusting the catalyst volume and the IPN feed rate. At a certain temperature and time, when the feed amount of IPN is constant, the volume of the filled catalyst determines the conversion rate of IPN.

If the space velocity of the catalyst is too high, the residence time of the IPN is insufficient and the conversion rate is low. When the space velocity of the catalyst is too small, the residence time of the IPN exceeds the actual reaction time, and the production efficiency is lowered. Preferably, the space velocity control of step a) and step b) is from 30 to 200 grams of IPN / (ml catalyst · hour), preferably from 50 to 150 grams of IPN / (ml of catalyst · hour), more preferably from 70 to 100 grams of IPN / (ml catalyst · hour).

The "airspeed" is the mass of the raw material IPN treated per unit time of the catalyst per unit time, and the unit is gram IPN / (ml catalyst · hour). It should be noted that when no catalyst is used in the steps a) and b), the volume of the "catalyst" in the unit of the space velocity "g IPN / (ml catalyst · hour)" should be correspondingly replaced for the filling reaction. The volume of inert material added is well understood by those skilled in the art.

According to the process of the invention, in step a), the molar ratio of liquid ammonia to IPN is from 5 to 200:1, preferably from 10 to 100:1, more preferably from 20 to 50:1.

According to the process of the invention, the imidization of IPN in step a) and step b) can be carried out without the addition of a solvent or in the presence of a solvent, such as an alcohol or an ether, such as methanol, ethanol, butanol Or tetrahydrofuran. Preferably, the reaction is carried out without adding a solvent.

According to the process of the present invention, the total conversion of IPN to imine in the product obtained in step b) reaches 90 to 99%, and the selectivity is higher than 99%, which is significantly higher than the current level in the industry.

According to the process of the present invention, preferably, step c) is carried out at a temperature of from 50 to 130 ° C and a pressure of from 10 to 30 MPa, preferably at a temperature of from 80 to 120 ° C and a pressure of from 15 to 20 MPa.

In a preferred embodiment, the reaction liquid in step c) has a temperature rise of 20 to 30 ° C, that is, the outlet temperature of the hydrogenation reactor in which step c) is carried out is 20 to 30 ° C higher than the inlet temperature. Such temperature rise control can It is guaranteed that the cis isomer ratio of the product IPDA is in the range of 75-80%, which is more favorable for downstream industrial applications.

According to the process of the invention, preferably, the molar ratio of hydrogen to IPN is from 3 to 1000:1, preferably from 10 to 500:1, particularly preferably from 20 to 100:1. Hydrogen may be mixed with the imidized material after the imidization reaction, or may be mixed with IPN or liquid ammonia prior to imidization.

According to the process of the present invention, step c) is a hydrogenation step which can be carried out by various existing hydrogenation methods without particular limitation.

According to the process of the present invention, the catalyst of step c) may be supported or Raney type, for example: supported copper, supported nickel, supported cobalt, Raney copper, Raney nickel or Raney cobalt, wherein the supported catalyst The carrier can be a common catalyst carrier.

According to the process of the present invention, the catalyst described in the step c) preferably employs a supported cobalt catalyst, more preferably a cobalt-alumina-supported cobalt catalyst, and particularly preferably a cobalt-alumina composite nanotube array membrane catalyst.

The cobalt and alumina composite nanotube array membrane catalyst is preferably prepared by the method disclosed in the patent document CN103464162A, and the preparation method comprises the following steps:

(1) preparing a Co-Al alloy sheet by smelting;

(2) using the Co-Al alloy sheet prepared in the step (1) as an anode, and performing constant pressure anodization in the electrolyte to obtain an alloy sheet having a CoO and Al ₂ O ₃ composite nanotube array film grown thereon, and then using Distilled water rinses the electrolyte attached to the surface of the alloy sheet;

(3) crushing the alloy flakes of the CoO and Al ₂ O ₃ composite nanotube array film prepared in the step (2) into alloy particles, which is a catalyst precursor;

(4) The catalyst precursor obtained in the step (3) is reduced with H ₂ to obtain a Co nanotube and Al ₂ O ₃ composite nanotube array membrane catalyst.

Preferably, when the Co-Al alloy sheet is smelted in the step (1), Co is added in an amount of 20 to 30% by weight, and Al is added in an amount of 70% to 80% by weight based on the sum of the weights of both Co and Al.

According to the process of the present invention, preferably, the space velocity on the catalyst used in step c) is controlled to be from 0.5 to 20 grams of IPN per (ml of catalyst per hour), more preferably from 5 to 15 grams of IPN per milliliter of catalyst per hour. ).

The three steps of the process of the invention may be carried out separately in three separate reactors or in the same reactor. It is preferably carried out in three separate reactors separately to facilitate continuous production.

Preferably, steps a) and b) are each carried out continuously using a tubular reactor.

Preferably, in steps a) and b), IPN and liquid ammonia are fed from below the tubular reactor and discharged above, in such a way that the reaction is more complete.

Preferably, the reaction of step c) is carried out in a tubular reactor, more preferably in a trickle bed tubular reactor.

The inventors started from the imidization reaction rule and found that when the initial acid value of IPN is in the range of 0.02-0.50 mgKOH/g, especially 0.05-0.30 mgKOH/g, and when the imidization reaction proceeds to After a certain degree, the imidization reaction is continued by adding an alkaline acid value regulator of 0.2 to 5 Torr, preferably 0.5 to 3 Torr of the initial IPN molar amount, and the finally obtained IPDA reaction solution ensures the content of the de-cyano product. In the lower case, the secondary amine, amino alcohol and bis-IPDA content are also lower than those reported in the literature, and the IPDA reaction yield is close to 99%. In addition, based on the above improvements, the reaction rate of the IPN imidization reaction step is greatly increased, and the space velocity on the imidization catalyst can reach 70 to 100 g IPN / (ml catalyst · hour), so that it can be achieved with less catalyst The same or better catalytic effect, the size of the two-stage imidization reactor is only about 1/5 of the traditional process, which reduces the basic investment of the device construction; at the same time, the reaction rate is greatly improved, the reaction time is saved, and the reaction time is only About 1/5 of the prior art.

"Pressure" as used in the present invention refers to gauge pressure.

DRAWINGS

Figure 1 shows a flow chart of an embodiment of the invention.

detailed description

The present invention will be further described below in conjunction with the embodiments. It should be noted that the following examples are not intended to limit the scope of the invention.

The quantitative analysis of each organic matter involved in the present invention was carried out on an Agilent Model 7890A gas chromatograph, and the gas chromatographic conditions were as follows:

Column: Agilent HP-5 (size 30m × 0.32mm × 0.25mm)

Inlet temperature: 280 ° C

Split ratio: 30:1

Column flow: 1.5ml/min

Column temperature: 100 ° C for 0.5 min

Increase to 260 ° C at 15 ° C / min for 8 min

Detector temperature: 280 ° C, hydrogen flow: 35 ml / min

Air flow: 350ml/min

A flow of a specific embodiment of the method of the present invention is shown in FIG. In this embodiment, the original The IPN and the liquid ammonia enter the primary imidization reactor 1 for imidization, and the obtained partially imidized reaction solution and the basic acid value regulator enter the secondary imidization reactor 2, and continue. The imidization reaction, the obtained product and hydrogen enter the hydrogenation reactor 3, and finally IPDA is obtained. In the process of the present invention, hydrogen may also be added prior to the imidization reaction step, that is, hydrogen and the raw material IPN together with the liquid ammonia are introduced into the primary imidization reactor 1.

The reactor used in the following examples is: the primary imidization reactor 1 and the secondary imidization reactor 2 have a diameter of 20 mm and a height of 100 mm, and the primary imidization reactor 1 is filled with 10 mL. Γ-alumina pellet having a diameter of 0.5 mm; the secondary imidization reactor 2 is filled with 10 mL of rod-shaped activated carbon having a diameter of 0.5 mm and a length of 2 mm; the hydrogenation reactor 3 has a diameter of 40 mm and a height of 200 mm, and is filled. Cobalt and alumina composite nanotube array membrane catalyst prepared by the method of Example 2 in the patent document CN103464162A.

The contents of the components described in the following examples and comparative examples are all weight percentages (wt%).

Example 1

a) The acid value of IPN is controlled at 0.30 mgKOH/g, and is added to the primary imidization reactor 1 together with liquid ammonia. The IPN feed rate is 700 g/h, the feed rate of liquid ammonia is 2850 g/h, and the hydrogen flow rate. 9500 standard L / h, temperature control at 40 ° C, reaction pressure 20MPa, to obtain a partially imidized reaction solution;

b) adding the initial IPN molar amount of 3 NaOH solids before entering the secondary imidization reactor 2, and then entering the secondary imidization reactor 2, the temperature is controlled at 20 ° C , the reaction pressure is 20 MPa;

c) The product obtained in step b) is fed to the hydrogenation reactor 3, the inlet temperature of the hydrogenation reactor 3 is controlled at 80 ° C, the outlet temperature is controlled at 100 ° C, and the reaction pressure is 20 MPa. The space velocity of the catalyst in each reactor is shown in Table 1:

Table 1

reactor 1 2 3 Airspeed (g IPN / (ml catalyst · hour)) 70 70 7

After the device was operated for 24 hours, it was sampled at the outlet of the primary imidization reactor 1, the outlet of the secondary imidization reactor 2, and the outlet of the hydrogenation reactor 3 for gas chromatography analysis. The results are shown in Table 2:

Table 2

Reactor 1 outlet Reactor 2 outlet Reactor 3 outlet IPN conversion rate 69.40% 98.20% - Double-IPDA precursor content 0.06% 0.06% - IPDA content - —— 98.80% Secondary amine content - —— 0.15% Amino alcohol content - —— 0.34% Double-IPDA content - —— 0.07%

De-cyano product content - —— 0.50%

Example 2

a) The acid value of IPN is controlled at 0.15mgKOH/g, and is added to the primary imidization reactor 1 together with liquid ammonia. The IPN feed rate is 800g/h, the feed rate of liquid ammonia is 1645g/h, and the temperature is controlled. At 50 ° C, the reaction pressure is 15 MPa to obtain a partially imidized reaction solution;

b) adding the initial IPN molar amount of 1.5 ‰ LiOH solid before entering the secondary imidization reactor 2, and then entering the secondary imidization reactor 2, the temperature is controlled at 30 ° C , the reaction pressure is 15 MPa;

c) The product obtained in step b) is fed to the hydrogenation reactor 3, and hydrogen is introduced at a flow rate of 2170 standard L/h. The inlet temperature of the hydrogenation reactor 3 is controlled at 80 ° C, the outlet temperature is controlled at 100 ° C, and the reaction pressure is 15 MPa. The space velocity of the catalyst in each reactor is shown in Table 3:

table 3

reactor 1 2 3 Airspeed (g IPN / (ml catalyst · hour)) 80 80 8

After 24 hours of operation, the apparatus was sampled at the outlet of the primary imidization reactor 1, the outlet of the secondary imidization reactor 2, and the outlet of the hydrogenation reactor 3 for gas chromatography analysis. The results are shown in Table 4:

Table 4

Reactor 1 outlet Reactor 2 outlet Reactor 3 outlet IPN conversion rate 62.50% 96.25% - Double-IPDA precursor content 0.07% 0.08% - IPDA content - —— 98.48% Secondary amine content - —— 0.18% Amino alcohol content - —— 0.39% Double-IPDA content - —— 0.08% De-cyano product content - —— 0.48%

Example 3

a) The acid value of IPN is controlled at 0.05 mg KOH/g, and is added to the primary imidization reactor 1 together with liquid ammonia. The IPN feed rate is 1000 g/h, the feed rate of liquid ammonia is 5150 g/h, and the hydrogen flow rate is 10000 standard L / h, the temperature is controlled at 60 ° C, the reaction pressure is 20 MPa, to obtain a partially imidized reaction liquid;

b) adding the initial IPN molar amount of 0.5 ‰ NaOH solid before entering the secondary imidization reactor 2, and then entering the secondary imidization reactor 2, the temperature is controlled at 40 ° C , the reaction pressure is 20 MPa;

c) The product obtained in step b) is fed to a hydrogenation reactor 3, the inlet temperature of the hydrogenation reactor 3 is controlled at 90 ° C, the outlet temperature is controlled at 120 ° C, and the reaction pressure is 20 MPa. The space velocity of the catalyst in each reactor is shown in Table 5:

table 5

reactor 1 2 3 Airspeed (g IPN / (ml catalyst · hour)) 100 100 10

After the device was operated for 24 hours, it was sampled at the outlet of the primary imidization reactor 1, the outlet of the secondary imidization reactor 2, and the outlet of the hydrogenation reactor 3, and analyzed by gas chromatography. The results are shown in Table 6:

Table 6

Reactor 1 outlet Reactor 2 outlet Reactor 3 outlet IPN conversion rate 62.90% 98.25% - Double-IPDA precursor content 0.04% 0.05% - IPDA content - —— 98.75% Secondary amine content - —— 0.13% Amino alcohol content - —— 0.30% Double-IPDA content - —— 0.05% De-cyano product content - —— 0.59%

Comparative example 1

In Comparative Example 1, except that the acid value of the reaction liquid was adjusted without adding NaOH at the inlet of the reactor 2, the other conditions were substantially the same as those in Example 1, and the results are shown in Table 9.

Table 9

Reactor 1 outlet Reactor 2 outlet Reactor 3 outlet IPN conversion rate 60.50% 85.14% - Double-IPDA precursor content 0.10% 0.93% - IPDA content - —— 86.76% Secondary amine content - —— 6.74% Amino alcohol content - —— 2.50% Double-IPDA content - —— 2.37% De-cyano product content - —— 0.25%

It can be seen that when the alkaline acid value modifier is not added in the step b), the IPN conversion rate at the outlet of the reactor 2 is significantly lower than that in the first embodiment, and the secondary amine, amino alcohol and bis-IPDA content in the product are higher, and the IPDA yield is higher. low.

Comparative example 2

In Comparative Example 2, except that the IPN acid value adjustment position was adjusted from the inlet of the reactor 2 to the inlet of the reactor 1, the other conditions were substantially the same as in the first embodiment. After the above changes, the IPN entering the reactor 1 was slightly alkaline. The results are shown in Table 10.

Table 10

Reactor 1 outlet Reactor 2 outlet Reactor 3 outlet IPN conversion rate 83.41% 99.57% - Double-IPDA precursor content not detected 0.02% - IPDA content - —— 89.69% Secondary amine content - —— 0.07%

Amino alcohol content - —— 0.27% Double-IPDA content - —— 0.02% De-cyano product content - —— 6.34%

It can be seen that when the acid value of IPN is prematurely adjusted to be weakly alkaline, a large amount of denitrification-based product is formed in the product, and the yield of IPDA is low.

Comparative example 3

In Comparative Example 3, the addition position of the basic acid value adjuster was adjusted to the inlet of the reactor 3, and other conditions were substantially the same as in Example 1. The results are shown in Table 11.

Table 11

Reactor 1 outlet Reactor 2 outlet Reactor 3 outlet IPN conversion rate 60.42% 85.22% - Double-IPDA precursor content 0.12% 0.90% - IPDA content - —— 94.90% Secondary amine content - —— 0.57% Amino alcohol content - —— 1.24% Double-IPDA content - —— 1.17% De-cyano product content - —— 0.65%

In this comparative example, the acid value of the reaction liquid was adjusted in the hydrogenation step c), and the content of secondary products such as secondary amine, amino alcohol and bis-IPDA in the product was higher than that in Example 1, and the yield of IPDA was low.

Comparative example 4

In the comparative example, except that the inlet of the primary imidization reactor 1 was not adjusted to the acid value of IPN (the acid value of the IPN raw material was 0.80 mgKOH/g), the other conditions were substantially the same as those in Example 1, and the results are shown in Table 12.

Table 12

Reactor 1 outlet Reactor 2 outlet Reactor 3 outlet IPN conversion rate 57.23% 92.22% - Double-IPDA precursor content 0.08% 0.16% - IPDA content - —— 94.29% Secondary amine content - —— 0.75% Amino alcohol content - —— 1.37% Double-IPDA content - —— 0.37% De-cyano product content - —— 0.20%

In the present comparative example, step a) did not adjust the acid value of IPN, the acid value of the IPN raw material was higher, the imidization reaction rate was significantly lower than that of Example 1, the imidization reaction was incomplete, and the by-products in the final product increased, IPDA The yield is low.

Comparative example 5

In Comparative Example 5, the inlet of the primary imidization reactor 1 was not adjusted to the acid value of IPN (the acid value of the IPN raw material was 0.80 mgKOH/g), and no alkaline acid value adjuster was added during the reaction, and the other operations were carried out simultaneously. example 1.

Table 13

Reactor 1 outlet Reactor 2 outlet Reactor 3 outlet IPN conversion rate 56.98% 87.54% - Double-IPDA precursor content 0.12% 0.21% - IPDA content - —— 82.32% Secondary amine content - —— 9.79% Amino alcohol content - —— 3.74% Double-IPDA content - —— 2.87% De-cyano product content - —— 0.09%

Claims (14)

A method for preparing 3-aminomethyl-3,5,5-trimethylcyclohexylamine, the method comprising the steps of: a) controlling the acid value of 3-cyano-3,5,5-trimethylcyclohexanone to 0.02 to 0.50 mgKOH/g, preferably 0.05 to 0.30 mgKOH/g, and liquid ammonia in a hydrogen atmosphere or The reaction is carried out in a hydrogen-free atmosphere to obtain a partially imidized reaction solution; b) adding a basic acid value adjuster to the partially imidized reaction liquid obtained in the step a) in an amount of the molar amount of the 3-cyano-3,5,5-trimethylcyclohexanone 0.2 to 5 Torr, preferably 0.5 to 3 Torr, and the imidization reaction is continued in a hydrogen atmosphere or in a hydrogen-free atmosphere; c) Hydrogenating the product obtained in step b) in the presence of hydrogen, liquid ammonia and a catalyst to form 3-aminomethyl-3,5,5-trimethylcyclohexylamine. The method according to claim 1, wherein in step a) 3-cyano-3,5,5-trimethylcyclohexanone is reacted with liquid ammonia to 3-cyano-3,5,5- The conversion rate of trimethylcyclohexanone is 50 to 80%, preferably 60 to 70%, to obtain the partially imidized reaction liquid. The method according to claim 2, wherein both steps a) and b) employ a catalyst, and the space velocity of the catalyst is from 30 to 200 g of 3-cyano-3,5,5-trimethylcyclohexanone. / (ml catalyst · hour), preferably 50 to 150 g of 3-cyano-3,5,5-trimethylcyclohexanone / (ml catalyst · hour), more preferably 70 to 100 g of 3-cyano-3 , 5,5-trimethylcyclohexanone / (ml catalyst · hour). The method according to claim 3, wherein the catalyst used in step a) and step b) is selected from the group consisting of an acidic metal oxide, an acidic ion exchange resin, a heteropolyacid, a sulfonic acid group-containing organopolysiloxane. Or activated carbon; preferably, step a) uses an acidic metal oxide as a catalyst, more preferably γ-alumina; preferably, step b) uses activated carbon as a catalyst. The method according to any one of claims 1 to 4, wherein the acid value of the step a) 3-cyano-3,5,5-trimethylcyclohexanone is carried out by adding an acidic compound or a basic compound. The adjustment wherein the acidic compound is selected from one or more of phosphoric acid, acetic acid, boric acid, oxalic acid, benzoic acid, and carbonic acid, more preferably phosphoric acid and/or acetic acid; the basic compound is selected from the group consisting of oxidation of an alkali metal An oxide, a hydroxide or a carbonate, an oxide, hydroxide or carbonate of an alkaline earth metal, or one or more of an oxide, hydroxide or carbonate of a rare earth metal, preferably an alkali metal One or more of an oxide, a hydroxide or a carbonate, or an oxide, hydroxide or carbonate of an alkaline earth metal, more preferably Li ₂ O, Na ₂ O, K ₂ O, Rb ₂ O, Cs ₂ O, LiOH, NaOH, KOH, RbOH, CsOH, Li ₂ CO ₃ , Na ₂ CO ₃ , K ₂ CO ₃ , Rb ₂ CO ₃ , MgO, CaO, SrO, BaO, Mg(OH) ₂ One or more of Ca(OH) ₂ , Sr(OH) ₂ , Ba(OH) ₂ , MgCO ₃ , CaCO ₃ , SrCO ₃ or BaCO ₃ , particularly preferably LiOH and/or NaOH. The method according to any one of claims 1 to 4, wherein step a) is carried out at a temperature of from 30 to 100 ° C and a pressure of from 0.5 to 30 MPa, preferably at a temperature of from 40 to 60 ° C and from 15 to 20 MPa. Under pressure. The method according to any one of claims 1 to 4, wherein in step a), the molar ratio of liquid ammonia to 3-cyano-3,5,5-trimethylcyclohexanone is from 5 to 200 1: is preferably from 10 to 100:1, more preferably from 20 to 50:1. The method according to any one of claims 1 to 4, wherein the alkaline acid number adjusting agent in the step b) is selected from the group consisting of alkali metal oxides, hydroxides or carbonates, alkaline earth metals. An oxide, hydroxide or carbonate, or one or more of an oxide, hydroxide or carbonate of a rare earth metal; preferably an oxide, hydroxide or carbonate of an alkali metal, or One or more of an oxide, a hydroxide or a carbonate of an alkaline earth metal; more preferably Li ₂ O, Na ₂ O, K ₂ O, Rb ₂ O, Cs ₂ O, LiOH, NaOH, KOH, RbOH, CsOH, Li ₂ CO ₃ , Na ₂ CO ₃ , K ₂ CO ₃ , Rb ₂ CO ₃ , MgO, CaO, SrO, BaO, Mg(OH) ₂ , Ca(OH) ₂ , Sr(OH) ₂ , One or more of Ba(OH) ₂ , MgCO ₃ , CaCO ₃ , SrCO ₃ or BaCO ₃ is particularly preferably LiOH and/or NaOH. The method according to any one of claims 1 to 4, wherein step b) is carried out at a temperature of from 20 to 80 ° C and a pressure of from 0.5 to 30 MPa, preferably at a temperature of from 20 to 40 ° C and from 15 to 20 MPa. Under pressure. The method according to any one of claims 1 to 4, wherein the total conversion of 3-cyano-3,5,5-trimethylcyclohexanone to the imine in the product obtained in the step b) is 90 to 99%, selectivity is higher than 99%. The method according to any one of claims 1 to 4, wherein the catalyst used in step c) is supported copper, supported nickel, supported cobalt, Raney copper, Raney nickel or Raney cobalt; preferably, The space velocity of the catalyst is 0.5 to 20 g of 3-cyano-3,5,5-trimethylcyclohexanone / (ml of catalyst·hour), more preferably 5 to 15 g of 3-cyano-3,5. 5-trimethylcyclohexanone / (ml catalyst · hour). The method of claim 11 wherein the catalyst used in step c) is a supported catalyst of cobalt and alumina composite, preferably a cobalt and alumina composite nanotube array membrane catalyst. The method according to any one of claims 1 to 4, wherein step c) is carried out at a temperature of 50 to 130 ° C and a pressure of 10 to 30 MPa, preferably at a temperature of 80 to 120 ° C and a temperature of 15 to 20 MPa. Under pressure. The method according to any one of claims 1 to 4, wherein the molar ratio of hydrogen to 3-cyano-3,5,5-trimethylcyclohexanone is from 3 to 1000:1. It is preferably 10 to 500:1, particularly preferably 20 to 100:1.

Images