WO2013147485A1

WO2013147485A1 - Method for preparing xylylenediamine

Info

Publication number: WO2013147485A1
Application number: PCT/KR2013/002481
Authority: WO
Inventors: 이상득; 안병성; 이현주; 주인범; 조민식; 김석수
Original assignee: 코오롱인더스트리 주식회사; 한국과학기술연구원
Priority date: 2012-03-27
Filing date: 2013-03-26
Publication date: 2013-10-03
Also published as: KR20130109457A; KR101399572B1

Abstract

The present invention relates to a method for preparing xylylenediamine from xylene, the economical and eco-friendly method comprising: cooling a reaction-produced gas produced from an ammoxidation reaction in order to selectively deposit phthalonitrile; and easily collecting unreacted xylene, tolunitrile, and ammonia and reusing same as reacting raw materials, thereby improving process yield.

Description

Method for preparing xylylenediamine

The present invention relates to a method for producing xylylenediamines by hydrogenating phthalonitriles obtained by ammoxidation of xylenes.

Xylylenediamine is useful as a raw material of polyamide resins, epoxy curing agents, or intermediates for isocyanate production, and is synthesized by ammoxidation of xylene to synthesize phthalonitrile and hydrogenation of the phthalonitrile.

Conventionally, in preparing xylylenediamine, Mitsubishi Chemical Co., Ltd. of Japan (MGC), in US Pat. No. 6,476,269, reacts xylene with ammonia and oxygen to ammonia to synthesize a reaction product gas in which phthalonitrile is the main product. Phtharonitrile capture step in which the reaction product gas of the oxidation reaction and ammonia oxidation reaction is directly contacted with the organic solvent by using an absorption tower or the like to selectively dissolve and recover phthalonitrile in the organic solvent. A method of preparing xylylenediamine comprising a hydrogenation step of synthesizing xylylenediamine by hydrogenating phthalonitrile, and a xylylenediamine purification step of recovering xylylenediamine by distilling and extracting a hydrogenation product. MGC has been proposed in US Pat. No. 6,646,163 for ammonia oxidation of xylene, organic Phtharonitrile capture step by solvent, phthalonitrile purification step to remove high boiling point impurities from phthalonitrile collected in organic solvent by primary separation and secondary separation to remove low boiling point material including organic solvent A method for preparing xylylenediamine, which comprises the step of synthesizing xylylenediamine by hydrogenation of tallowonitrile, has been proposed. A similar method is presented. However, U.S. Patent No. 7,915,452 does not separate high-boiling impurities from phthalonitrile collected in an organic solvent, but separates and removes only low-boiling substances including an organic solvent, and then hydrogenates them. No. 0168474 is characterized by adding ammonia to dissolve the molten phthalonitrile and removing the low boiling point material from the phthalonitrile trapped in the organic solvent to dissolve the high boiling point insoluble components and then hydrogenating. BASF also proposes a process for preparing xylylenediamine similar to MGC in U.S. Pat.Nos. 7,323,598, 7,363,610, 7,528,284 and 7,541,497, which discloses N-methyl-2-pyrrolidone ( NMP) is used as a phthalonitrile collection solvent.

Like the xylylenediamine production method described above, the production method, characterized in that the reaction product gas of the ammonia oxidation reaction of xylene in direct contact with the organic solvent in the absorption tower to dissolve and recover the phthalonitrile in the organic solvent The organic solvent, unreacted xylene, tolunitrile (tolunitrile), which is an intermediate of the ammonia oxidation reaction, in the phthalonitrile capture step is accompanied by a considerable amount of exhaust gas and has a problem of flowing out to the top of the absorption tower. Although organic solvents, xylenes and tolunitriles can be recovered from the flue-gas, it is very difficult to economically separate xylenes and tolunitriles, which can be reused as organic solvents and raw materials, from the recovered mixture. One flue gas has a disadvantage that it can only be released to the atmosphere after treatment by incineration and the like.

The problem to be solved by the present invention is a method of synthesizing the corresponding phthalonitrile through ammonia oxidation of xylene, and to produce a xylylenediamine by hydrogenating the synthesized phthalonitrile, there is almost no loss of organic solvent The present invention provides a method for producing an economical xylylenediamine that is easy to recover, unreacted xylene and tolunitrile, and the process is simple.

In order to solve the above problems, the present invention provides a method for producing xylylenediamine from xylene,

(1) an ammonia oxidation step of reacting xylene with ammonia and an oxygen-containing gas under a catalyst to produce a reaction product gas containing phthalonitrile;

(2) phthalonitrile recovery step of cooling the reaction gas of the ammonia oxidation reaction to selectively precipitate phthalonitrile, and then dissolve the precipitated phthalonitrile with an organic solvent;

(3) The reaction product gas of the ammonia oxidation reaction remaining after the phthalonitrile was precipitated by step (2) was cooled, condensed water, xylene and tolunitrile in the reaction product gas, and the organic layer separated Xylene and tolunitrile recovery step for reuse as a raw material of the ammonia oxidation step of step (1);

(4) a hydrogenation step of adding liquid ammonia to the phthalonitrile-dissolved solution obtained in step (2) and then hydrogenating to synthesize xylylenediamine; And

(5) xylylene comprising the step of purifying xylylenediamine to obtain high purity xylylenediamine by separating ammonia, organic solvent and heavy water from the hydrogenation product containing xylylenediamine obtained in step (4) Provided are methods for preparing diamines.

According to one embodiment of the invention, the catalyst of step (1) is made of vanadium (V), chromium (Cr), antimony (Sb), molybdenum (Mo), iron (Fe) and tungsten (W) It may be an oxide of one or more metals selected from the group, and the oxygen-containing gas may be air containing oxygen, air diluted with an inert gas, or oxygen.

According to another embodiment of the present invention, the cooling of the step (2) is preferably performed at a sublimation temperature range of 80 ℃ to phthalonitrile, the organic solvent of the step (2) is an aromatic hydrocarbon, saturated alicyclic Hydrocarbons, heterocyclic compounds, aromatic nitriles, heteronitriles, imidazoles, tolunitriles, methylbenzylamines, xylylenediamines, N-methyl-2-pyrrolidone (NMP), mesitylene and water silica It may be selected from the group consisting of.

According to another embodiment of the present invention, the cooling in step (3) may be performed in a range of 0 ° C to 50 ° C, and the hydrogenation of step (4) is performed under a catalyst, in a range of 40 ° C to 150 ° C. Temperature and a pressure in the range of 3 to 30 MPa, and the catalyst used for the hydrogenation of step (4) is preferably a nickel or cobalt-containing catalyst.

According to another embodiment of the present invention, the ammonia separated in the step (5) is recycled by recycling to the hydrogenation step of the step (4), the organic solvent separated in the step (5) is the (2 Can be recycled to the phthalonitrile recovery step.

The xylylenediamine production method according to the present invention can be easily recovered from the reaction product gas of the ammonia oxidation reaction, and thus can be reused as a reaction raw material, and it is environmentally friendly by reducing the loss of organic solvents. And economical.

1 is a schematic diagram of a case of carrying out the method according to the present invention.

2 is a schematic diagram of a reactor used for ammonooxidation according to an embodiment of the present invention.

Hereinafter, the present invention will be described in more detail.

The present invention relates to a method for producing phthalonitrile from xylene, in which the reaction product gas synthesized by the ammonia oxidation reaction of xylene is cooled to sublimate phthalonitrile and precipitated selectively, and tolunitrile is added together with xylene. When used as a raw material for the ammonia oxidation reaction, the yield of phthalonitrile is improved compared to the case of using only xylene, and ammonia is added to the phthalonitrile solution dissolved in the organic solvent, and when hydrogenated, the conversion rate of phthalonitrile of 99% or more and Based on the fact that xylylenediamine can be synthesized in a yield of 97% or more, and the yield of cyanobenzylamine, a by-product that is difficult to separate because of similar boiling point to xylylenediamine, can be controlled to 500 ppm or less. Was conceived.

Method for producing xylylenediamine according to the present invention,

(5) purifying the xylylenediamine to obtain high purity xylylenediamine by separating ammonia, organic solvent and heavy water from the hydrogenation product containing xylylenediamine obtained in step (4).

In the step (1), known a fixed bed catalyst or a fluidized bed catalyst may be used for the ammonia oxidation, and in particular, vanadium (V), chromium (Cr), antimony (Sb), molybdenum (Mo), iron ( An oxide catalyst of at least one metal selected from the group consisting of Fe) and tungsten (W) is preferred, and as the reaction raw material, at least one material selected from the group consisting of xylene, ammonia and oxygen-containing gas may be supplied. The xylene is at least one xylene compound selected from the group consisting of o-xylene (o-xylene), m-xylene (m-xylene) and p-xylene (p-xylene), the phthalonitrile prepared therefrom is o At least one phthalonitrile selected from the group consisting of o-phthalonitrile, isophthalonitrile, and terephthalonitrile, in particular The process according to the command is, by supplying the raw material of xylene m- xylene is more preferable for the production of isophthaloyl nitrile.

The amount of xylene supplied in the reaction raw material used in step (1) is 0.01 to 1.0 kg / (h · kg-catalyst) (mass flow rate per unit time of xylene supplied per unit mass (kg) of catalyst charged to the reactor (kg / h)), more preferably in the range of 0.03 to 0.3 kg / (h · kg-catalyst), the yield of phthalonitrile is good within the xylene feed range. It is also possible to replace a portion of xylene with tolunitrile and to supply it with a mixture of xylene and tolunitrile, and the concentration of tolunitrile in the mixture is not particularly limited, but 50 wt% or less is suitable.

The supply amount of ammonia in the reaction raw material used in step (1) may be 2 to 30 moles with respect to 1 mole of xylene, but the yield of phthalonitrile is better at 2 to 15 moles, and the oxygen-containing gas contains oxygen It may be one air, air diluted with an inert gas, or oxygen, and the amount of oxygen supplied in the oxygen-containing gas may be 3 moles or more with respect to 1 mole of xylene, but preferably 3 to 30 moles, more preferably 3 It is 10 mol, and the yield of phthalonitrile is favorable and a publication yield is high.

The reaction of step (1) may be carried out at a temperature range of 300 ° C to 500 ° C, preferably at a temperature of 350 ° C to 470 ° C and a pressure of normal pressure to 300 kPa, within the temperature and pressure range The conversion of xylene in is good, and by-products such as carbon dioxide, hydrogen cyanide and benzonitrile can be suppressed to produce phthalonitrile in high yield.

The reaction product gas generated in step (1) is composed of phthalonitrile, unreacted xylene, tolunitrile, water vapor, ammonia, air, carbon dioxide, and the like. Although it may be carried out in the sublimation temperature range of the deronitrile, a temperature of 10 ° C. lower than the sublimation temperature of the phthalonitrile is more preferable. A cooling device for depositing phthalonitrile may be a coil type heat exchanger or a cylindrical heat exchanger. The organic solvent of step (2) is aromatic hydrocarbon, alicyclic hydrocarbon, heterocyclic compound, aromatic nitrile, heterocyclic nitrile, imidazole, tolunitrile, methyl Benzylamines, xylylenediamines, N-methyl-2-pyrrolidone, mesitylene and water silicate; and may be selected from the group consisting of imidazoles, methylbenzylamines, and xylyl Rendiamines are more preferable, and the solvent is a substance having high solubility in phthalonitrile or produced in xylylenediamine manufacturing process, and is inert to hydrogenation of phthalonitrile and is not separated. It has the advantage of being used directly.

The cooling of the step (3) may be in the range of 0 ℃ to 50 ℃, it is more preferable to be carried out in the range of 5 ℃ to 40 ℃ because it can increase the recovery rate of xylene and tolunitrile, lower the energy cost is economical In addition, the condensate condensed in step (3) may be separated into an organic layer composed mainly of xylene and tolunitrile and a water layer composed mainly of water, and the organic layer may be used as a reaction material in the ammonia oxidation step.

The hydrogenation reaction of step (4) may be performed in a fixed bed reactor filled with a catalyst or a multi-tube reactor capable of heat exchange, and when using a fixed bed reactor, a cooler is required along with the circulation of the reaction product to remove the heat of reaction. do.

According to the invention, the hydrogenation of step (4) can be carried out under a catalyst, a temperature in the range of 40 ℃ to 150 ℃, and a pressure in the range of 3 to 30 MPa, a temperature in the range of 60 ℃ to 130 ℃, and It is preferably carried out under a pressure in the range of 5 to 15 MPa, and the catalyst used for the hydrogenation of step (4) may be a nickel or cobalt-containing catalyst, mainly used in a form supported on a support, and step (4) The phthalonitrile used for the hydrogenation of is at least one phthalonitrile selected from the group consisting of o-phthalonitrile, isophthalonitrile and terephthalonitrile. It is more preferable to prepare m-xylylenediamine by supplying a tonitrile, and the supply amount of the phthalonitrile of the step (4) may be 0.01 to 1.0 kg / (h kg-catalyst), wind The yield of xylylenediamine in the phthalonitrile supply range is preferably in the range of 0.03 to 0.3 kg / (h · kg-catalyst), and the supply amount of ammonia is 0.5 to 50% by weight based on 1 weight of phthalonitrile. It may be, but preferably 1 to 10 by weight in the ammonia supply range side reaction is suppressed and the yield of xylylenediamine is good, according to the present invention, the hydrogenation of step (4) is ammonia, organic It contains low boiling materials, such as a solvent, xylylenediamine, and high boiling materials.

Purification of step (5) can be carried out through a distillation or evaporation process, both batch or continuous. In the distillation process, a conventional distillation column, such as a packed column or a multistage column, may be used. When the xylylenediamine is separated using a distillation tower, low ammonia and organic solvents such as ammonia are first separated into a column top, followed by xylylenediamine. The column top is separated and purified, the heavy water can be removed to the bottom of the column, the distillation process can be carried out at normal pressure or less, it is preferable that the pressure of 0.03 MPa or less, if the distillation pressure is out of the above range xylylene High decomposition products are formed by the decomposition and polymerization of the diamine, and the recovery rate of xylylenediamine is lowered.

Hereinafter, the present invention will be described in more detail with reference to preferred embodiments in order to help the understanding of the present invention. However, the following examples are merely provided to more easily understand the present invention, and the contents of the present invention are not limited thereto.

Example 1.

Ammonia oxidation, phthalonitrile recovery, xylene and tolunitrile recovery, hydrogenation, and xylylenediamine purification experiments were performed according to the process flow shown in FIG. 1.

The ammonia oxidation of m-xylene was carried out using a tubular reactor with two reaction zones shown in FIG. 2. 38 g and 54 g of vanadium containing catalyst were charged to the first and second reaction zones of the tubular reactor having an outer diameter of 25.4 mm, respectively. The reaction was carried out by supplying 9.0 g / h of m-xylene, ammonia and air to the first reaction zone of the reactor, and supplying only air to the second reaction zone. The molar ratio of ammonia to m-xylene supplied to the first reaction zone was 4, and the molar ratio of oxygen was 2. The amount of air supplied to the second reaction zone was 175% of the amount of air supplied to the first reaction zone (molar ratio of oxygen to m-xylene supplied to the first reaction zone was 3.5). Reactor cooling used a molten salt bath. At a molten salt temperature of 383 ° C., the hot spot temperature of the first reaction zone was 418 ° C., the hot spot temperature of the second reaction zone was 431 ° C., and the reaction pressure was atmospheric pressure.

The reaction product gas of the ammonia oxidation reaction was passed through the first heat exchanger in which the refrigerant at 100 ° C. was circulated and the second heat exchanger in which the refrigerant at 10 ° C. was circulated. In the first heat exchanger, isophthalonitrile was precipitated in the solid state, and in the second heat exchanger, the condensate was separated into an organic layer composed mainly of xylene and intermediate m-tolunitrile and a water layer composed mainly of water. It became. Analysis of the contents captured by the two heat exchangers produced 61.0 moles of isophthalonitrile and 16.6 moles of m-tolunitrile with respect to 100 moles of m-xylene as a reaction material, and 3.7 moles of m-xylene were recovered. Isophthalonitrile collected in the first heat exchanger was recovered by dissolving in 1-methyl imidazole, an organic solvent. The temperature of 1-methyl imidazole was 60 degreeC and the usage-amount was about 4 times of isophthalonitrile by weight ratio.

An isophthalonitrile solution dissolved in 1-methyl imidazole was fed to a tubular reactor having an outer diameter of 25.4 mm filled with 100 g of cobalt containing catalyst at a flow rate of 30 g / h. The reactor was also fed with ammonia at a rate of 12 g / h. The reaction pressure was 8 MPa and the reaction temperature was 105 ° C. As a result of analyzing the reaction product, the yield of m-xylylenediamine was 98%.

The hydrogenation product was separated using a batch distillation apparatus. Low abundances such as ammonia and 1-methyl imidazole were first separated and removed, and then m-xylylenediamine was recovered to the top. The recovered m-xylylenediamine had a purity of 99.9% or more, and contained 300 ppm of 3-cyanobenzylamine and 50 ppm of isophthalonitrile as impurities.

Example 2.

Isophthalonitrile synthesis was carried out in the same ammonia oxidation reactor as in Example 1. However, instead of m-xylene, a mixture of 72 mol% m-xylene and 28 mol% m-tolunitrile was fed to the reactor. At a melt salt temperature of 385 ° C., the hot spot temperature of the first reaction zone was 434 ° C., the hot spot temperature of the second reaction zone was 418 ° C., and the reaction pressure was atmospheric pressure.

The reaction product gas of the ammonia oxidation reaction was passed through a heat exchanger in which a refrigerant at 100 ° C. was circulated and a heat exchanger in which a refrigerant at 10 ° C. was circulated. Analysis of the contents captured by the two heat exchangers showed that 71.4 moles of isophthalonitrile were produced with respect to 100 moles of m-xylene and m-tolunitrile mixtures, 13.6 moles of m-tolunitrile and 1.5 m-xylene 1.5. The mole was recovered.

Claims

In the method for producing xylylenediamine from xylene,

(1) an ammonia oxidation step of reacting xylene with ammonia and an oxygen-containing gas under a catalyst to produce a reaction product gas containing phthalonitrile;

(2) phthalonitrile recovery step of cooling the reaction gas of the ammonia oxidation reaction to selectively precipitate phthalonitrile, and then dissolve the precipitated phthalonitrile with an organic solvent;

(3) The reaction product gas of the ammonia oxidation reaction remaining after the phthalonitrile was precipitated by step (2) was cooled, condensed water, xylene and tolunitrile in the reaction product gas, and the organic layer separated Xylene and tolunitrile recovery step for reuse as a raw material of the ammonia oxidation step of step (1);

(4) a hydrogenation step of adding liquid ammonia to the phthalonitrile-dissolved solution obtained in step (2) and then hydrogenating to synthesize xylylenediamine; And

(5) xylylene comprising the step of purifying xylylenediamine to obtain high purity xylylenediamine by separating ammonia, organic solvent and heavy water from the hydrogenation product containing xylylenediamine obtained in step (4) Process for the preparation of diamines.
According to claim 1, wherein the catalyst of step (1) is one selected from the group consisting of vanadium (V), chromium (Cr), antimony (Sb), molybdenum (Mo), iron (Fe) and tungsten (W) It is an oxide of the above metal, The manufacturing method of xylylenediamine.
The method for producing xylylenediamine according to claim 1, wherein the oxygen-containing gas of step (1) is air containing oxygen, air diluted with an inert gas, or oxygen.
The method for preparing xylylenediamine according to claim 1, wherein the cooling in the step (2) is performed at a sublimation temperature range of 80 ° C to phthalonitrile.
The organic solvent of claim 1, wherein the organic solvent of step (2) is an aromatic hydrocarbon, a saturated alicyclic hydrocarbon, a heterocyclic compound, an aromatic nitrile, a heterocyclic nitrile, imidazoles, tolunitriles, methylbenzylamines or xylylenes. Diamines, N-methyl-2-pyrrolidone (NMP), mesitylene and the manufacturing method of xylylenediamine characterized by the above-mentioned.
The method for preparing xylylenediamine according to claim 1, wherein the cooling in step (3) is performed in a range of 0 ° C to 50 ° C.
The method of claim 1, wherein the hydrogenation of step (4) is carried out under a catalyst, at a temperature in the range of 40 ° C to 150 ° C, and at a pressure in the range of 3 to 30 MPa.
8. The process for producing xylylenediamine according to claim 7, wherein the catalyst is a nickel or cobalt-containing catalyst.
According to claim 1, wherein the ammonia separated in the step (5) is recycled by recycling to the hydrogenation step of the step (4), the organic solvent separated in the step (5) is phthalate of step (2) A method for producing xylylenediamine, which is recycled by circulating in a nitrile recovery step.
The method of claim 1, wherein the xylene is at least one xylene compound selected from the group consisting of o-xylene (o-xylene), m-xylene (m-xylene) and p-xylene (p-xylene), Nitrile is at least one phthalonitrile compound selected from the group consisting of o-phthalonitrile, isophthalonitrile and terephthalonitrile, said xylylenediamine being o-xylylenediamine, m-xylylenediamine and p At least one xylylenediamine selected from the group consisting of xylylenediamine.