KR20110010072A - Method for manufacturing para-phenylenediamine of aramid fiber and polymer using the same - Google Patents

Abstract

PURPOSE: A method for preparing para-phenylenediamine for aramid fiber is provided to reduce a generation amount of wastewater by not using surfactants and water and to ensure high purity using hydrocarbon as a solvent. CONSTITUTION: A method for preparing para-phenylenediamine for aramid fiber comprises the steps of: preparing para-nitroaniline; and reacting the para-nitroaniline with hydrogen gas using precious metal catalysts under a hydrocarbon solvent. The precious metal catalyst includes Group 8 metal on a periodic table and is dipped in a carrier. The carrier includes at least one selected from carbon, alumina, silica, zirconia, titanium, silicoaluminate, alkaline earth metal and alkali metal.

Description

Method for manufacturing para-phenylenediamine for preparing aramid fibers and polymer using the same

The present invention relates to a method for preparing paraphenylenediamine and a polymer using the same, and more particularly, to a paraphenylenediamine using a paranitroaniline as a starting material and a hydrogenation method for hydrogenating the paranitroaniline. It relates to a manufacturing method and a polymer using the same.

Paraphenylenediamine is used as a cosmetic raw material, antioxidant, fuel additive, and dye synthesis raw material. In particular, it is used as a polymerization raw material of aramid fiber which has high strength, high elasticity, and high heat resistance property.

Such paraphenylenediamine can be manufactured by various methods. In particular, the manufacturing method of paranitroaniline using the hydrogenation method is widely used. This hydrogenation method uses a metal catalyst to add hydrogen gas to paranitroaniline to perform the hydrogenation reaction. This hydrogenation reaction is carried out under a solvent, usually using a polar solvent such as an alcohol capable of dissolving the starting material paranitroaniline.

However, when using such a polar solvent, the initial investment cost is increased by installing a separate distillation unit to separate and recover the water and the polar solvent produced after the completion of the hydrogenation reaction. In particular, when used as a raw material for the polymerization of aramid fibers, the paraphenylenediamine prepared by the above-described method is inferior in purity and the aramid fibers produced therefrom did not exhibit the level of tensile strength required by the industry.

In order to solve this problem, a method of adding a water and a surfactant to a hydrocarbon solvent and then performing a hydrogenation reaction using a Raney-Ni catalyst has been proposed.

However, this method has a problem in that the production rate is lowered because the oil and water separation process for separating the water and the hydrocarbon solvent including the reactants after completion of the reaction is required. In addition, such a method has a problem in that the economical efficiency is lowered by using an expensive surfactant and performing a separate surfactant recovery process after completion of the reaction. In addition, this method has a problem in that the reaction time is long and the yield and purity are lowered by using Raney nickel having low activity and sustainability.

The present invention is designed to solve the above problems, the present invention is economical by reducing the amount of waste water generated by the use of surfactants and water and simplify the process, high purity by using hydrocarbon as a solvent It is an object of the present invention to provide a method for preparing paraphenylenediamine and a polymer using the same, which can reduce the initial investment cost and reduce the production cost as the hydrocarbon is easily recovered.

As an aspect of the present invention for achieving the above object, the present invention comprises the steps of preparing para-nitroaniline (para-nitroaniline); And it provides a method for producing paraphenylenediamine comprising the step of hydrogenating the hydrogen gas to the paranitroaniline using a noble metal catalyst under a hydrocarbon solvent.

As another aspect of the present invention for achieving the above object, the present invention provides a polymer prepared by polymerizing para-phenylenediamine prepared by the above production method with an aromatic diacid compound. .

The present invention has the following effects.

First, according to the present invention, by using only a hydrocarbon solvent without using water and a surfactant, the recovery of the hydrocarbon solvent is easy and the process is simple, so that economic efficiency and high yield of paraphenylenediamine can be obtained.

Second, according to the present invention, as the reaction rate is improved by using the optimum noble metal catalyst, it is possible to obtain paraphenylenediamine having excellent economic efficiency and high purity and high yield.

Such high purity and high yield of paraphenylenediamine can be used in various fields such as raw materials for aramid polymers.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention. Accordingly, the invention includes all modifications and variations that fall within the scope of the invention as set forth in the claims and their equivalents.

Hereinafter, a method for preparing paraphenylenediamine according to the present invention and specific examples of a polymer using the same will be described in detail.

First, a method for preparing para-phenylenediamine (PPD) from para-nitroaniline (PNA) will be described. The method for preparing paraphenylenediamine of the present invention includes preparing paranitroaniline and hydrogenating the paranitroaniline with hydrogen gas using a noble metal catalyst under a hydrocarbon solvent.

The paranitroaniline can be prepared by conventional methods. That is, paranitroaniline is prepared by reacting chlorobenzene with nitric acid to obtain paranitrochlorochlorobenzene, and then reacting paranitrochlorochlorobenzene with ammonia.

The purity of such paranitroaniline may be 99.6% or more. If the purity of the paranitroaniline is less than 99.6%, the purity of the paraphenylenediamine prepared therefrom is bound to fall. In addition, aramid fibers produced using paraphenylenediamine having such low purity have low strength and non-uniform physical properties.

Next, a hydrogenation step of reacting hydrogen gas to the paranitroaniline using a noble metal catalyst under a hydrocarbon solvent will be described.

The hydrocarbon used as the solvent is preferably an aliphatic hydrocarbon having 5 to 10 carbon atoms. Since the aliphatic hydrocarbon has a low boiling point, it is easy to separate and recover. Since the aliphatic hydrocarbon does not dissolve the paraphenylenediamine produced after the hydrogenation reaction, the aliphatic hydrocarbon is easily separated and recovered, and is incompatible with the water produced after the reaction. It is easy to separate and recover the solvent from water.

The hydrocarbon is n-pentane, n-hexane, n-heptane, n-octane, n-nonne, n-nonane nonane, decane, cyclopentane, cyclohexane, cycloheptane, methyl-cyclohexane, 2-ethylhexane ), 2-methylpentane, isopentane, isohexane, isoheptane, and isooctane.

The present invention does not use water as a solvent. That is, water is not artificially added to the starting. If such water is added and used as a solvent, since the reaction is completed, the oil and water separation process is performed to separate the water and the hydrocarbon solvent. On the other hand, when the reaction is performed without adding water, after the reaction is completed, the product is separated through a flash process, and a small amount of water and a hydrocarbon solvent, which are side reactions, are separated through a separate oil and water separation process. The production speed has an advantage.

In the present invention, the reaction is not carried out in a suspension containing a surfactant. That is, the reaction is carried out using a solvent containing only a hydrocarbon containing no expensive surfactant. If the surfactant is included, after the reaction is completed, the surfactant is recovered and recycled through a separate recovery process using a membrane or the like, and as such an additional process is required, the process is complicated and the recovery is not easy. . On the other hand, if the reaction is carried out without the addition of a surfactant, there is no need for a separate process to recover it, and thus the production speed is excellent, and since the surfactant is not included in the product, high purity and high yield of paraphenylenediamine can be obtained. It becomes possible.

The noble metal catalyst may include a Group 8 metal element on the periodic table. Such Group 8 metal elements can easily break the bonds of the hydrogen molecules, which can greatly activate the reaction.

Such a noble metal catalyst may include at least one of palladium (Pd), rhodium (Rh), ruthenium (Ru), and platinum (Pt). Such a noble metal catalyst exhibits excellent activity compared to other metal catalysts and has high stability that does not easily degrade even if used repeatedly. However, these precious metals are characterized by a rather expensive nature, and in order to solve this problem, it is important to minimize the particle size of the precious metal to maximize the number of active phases using a minimum amount of precious metal.

Accordingly, the present invention may include a catalyst in which the noble metal is supported on a carrier. Such a carrier has a large surface area by having a large amount of fine pores, and thus plays a role of greatly activating the catalyst and easily controlling the catalyst. If the noble metal is carried in the pure state without being supported on the carrier, it may be swept away by hydrogen gas passing through the catalyst bed. On the other hand, when the catalyst supported on the noble metal is used, the reaction can be performed smoothly by preventing the loss of the catalyst. In addition, the carrier can prevent the catalyst activity from being lowered by aggregation of the noble metals with each other during the reaction.

The carrier may comprise at least one of carbon, alumina, silica, zirconia, titanium, silicoaluminates, alkaline earth metals, and alkali metals. The carbon may be activated carbon, activated nanotubes, or activated carbon particles, but is not limited thereto.

The step of hydrogenation may be carried out in a state of maintaining a reaction temperature of 20 ~ 200 ℃, it may be more preferably carried out in a state of maintaining a reaction temperature of 50 ~ 150 ℃. If the reaction temperature is less than 20 ℃ reaction rate is too slow, while if the reaction temperature exceeds 200 ℃ reaction rate is too fast it may be difficult to control the process smoothly.

The hydrogenation may be performed under a reaction pressure of 5-100 bar, and more preferably, under a reaction pressure of 5-50 bar. If the reaction pressure is less than the 5 bar, the reaction rate is too slow, while if the reaction pressure exceeds the 50 bar, the reaction rate is too fast, it may be difficult to smoothly control the process.

The amount of the noble metal catalyst used in the hydrogenation may be 0.1 to 4 parts by weight based on 100 parts by weight of paranitroaniline. If the amount of the noble metal catalyst is less than 0.1 part by weight, the reaction rate is too slow, while the amount of the noble metal catalyst is used in excess of 4 parts by weight does not significantly improve the reaction rate. However, when preparing paraphenylenediamine using conventional Raney nickel, at least about 10 times higher than Raney nickel should be used to obtain high purity and yield. As such, when Raney nickel is used, as the amount of the catalyst is increased, economical efficiency is lowered, a uniform reaction may not be obtained, and there may be a limit in obtaining high purity and yield. However, in the case of using the noble metal catalyst of the present invention, since the addition amount of the catalyst is small, as the reaction proceeds smoothly, high purity and yield can be obtained, and as the reaction time is short, the productivity can be greatly improved, and the catalyst is easily recovered. can do.

The amount of paranitroaniline used in the hydrogenation may be 20 to 200 parts by weight based on 100 parts by weight of the hydrocarbon solvent. If the amount of paranitroaniline is less than 20 parts by weight, an unnecessary amount of solvent may be used. On the other hand, if the amount of paranitroaniline exceeds 200 parts by weight, the hydrogenation reaction may proceed rapidly and exothermic control may be difficult. have.

After the step of hydrogenation, the paraphenylenediamine as a product can be easily separated from the solvent through a filtering process.

In addition, an oil and water separation process may be performed to separate and recover the hydrocarbon solvent from the water, which is a side reactant. Since the water and the hydrocarbon solvent are incompatible, the separation of each layer easily occurs, thereby allowing the separation and recovery of each other through a simple oil and water separation process. Accordingly, the present invention does not require a separate distillation apparatus required for separating and recovering the polar solvent from water as a by-product after completion of the reaction by using a hydrocarbon solvent which is a nonpolar solvent. As a result, as the production process is simplified, the production period can be shortened and the initial investment cost can be reduced.

The paraphenylenediamine prepared as described above has a purity of at least 99.6%. That is, the said paraphenylenediamine contains less than 0.4% of impurities. The impurities are para-nitrochlorobenzene, para-nitroaniline, para-chloroaniline, para-chloroaniline, ortho-phenylenediamine, meta-phenylenediamine ), Or aniline.

When the aramid polymer is prepared by reacting with an aromatic diacid using paraphenylenediamine having a purity of less than 99.6%, the aramid polymer has a low average molecular weight and a wide molecular weight distribution, whereby the aramid fibers prepared therefrom are tensile Strength and modulus of elasticity will fall.

The aramid polymer may be prepared through the following process.

A polymerization solvent is prepared by adding an inorganic salt such as a halogenated alkali metal salt or a halogenated alkali earth metal salt to an organic solvent such as an amide or urea system. Subsequently, the mixed solution is prepared by dissolving the paraphenylenediamine having a purity of 99.6% or more in the prepared polymerization solvent. Subsequently, while stirring the mixed solution, an aromatic diacid compound such as an aromatic diacid chloride is added to the mixed solution to perform a polymerization process. When the polymerization process is completed, the aramid polymer is completed through a neutralization step for removing the acid and a step of extracting the polymerization solvent and water, followed by a drying step.

The aramid fiber may be prepared through the following process.

The aramid polymer is dissolved in concentrated sulfuric acid solvent to prepare spinning dope. The filaments are formed by spinning the spin dope using a spinneret and then solidifying in a coagulation bath via an air gap. The filament is washed with water and dried to complete aramid fiber production. The aramid fibers thus prepared will have excellent tensile strength and elastic modulus.

Hereinafter, the present invention will be described in detail through examples and comparative examples. However, the following examples are merely to aid the understanding of the present invention, and the scope of the present invention should not be limited thereto.

1) preparing paraphenylenediamine

Example  One

Put 100 parts by weight of n-hexane as a solvent and add 50 parts by weight of nitroaniline to the solvent while stirring with 2 liter of pressure reactor equipped with a cooler and a thermometer, and then use 140 parts by weight of 5% Pd / C catalyst at 140 ° C. Paraphenylenediamine was prepared by performing a hydrogenation reaction under a reaction temperature of 20 bar and a hydrogen pressure of 20 bar.

Example  2 to 5

In Example 1 described above, paraphenylene was prepared in the same manner as in Example 1, except that n-heptane, n-octane, cyclohexane, and cycloheptane were used instead of the n-hexane solvent. Diamine was prepared.

Example  6 to 8

In Example 1 described above, paraphenylenediamine was prepared in the same manner as in Example 1 except that Pt / C, Ru / C, and Rh / C were used instead of the Pd / C catalyst.

Example  9

In Example 1 described above, paraphenylenediamine was prepared in the same manner as in Example 1, except that 4.0 parts by weight of the Pd / C catalyst was added.

Comparative example  One

In Example 1 described above, paraphenylenediamine was prepared in the same manner as in Example 1 except that polyoxyalkylene glycol ether was added to n-hexane as water and a surfactant. The content ratio of n-hexane, water, and surfactant was 5: 3: 0.2.

Comparative example  2 to 4

In Example 1 described above, paraphenylenediamine was prepared in the same manner as in Example 1 except that methanol, ethanol, and tetrahydrofuran (THF) were used instead of the n-hexane solvent.

Comparative example  5

In Example 1 described above, paraphenylenediamine was prepared by the same method as Example 1 except for using the Raney-Ni catalyst not supported on the carrier instead of the Pd / C catalyst.

Comparative example  6

In Comparative Example 5, paraphenylenediamine was prepared in the same manner as in Comparative Example 5 except for adding 5 parts by weight of the Raney-Ni catalyst.

Comparative example  7

In Example 1 described above, paraphenylenediamine was prepared in the same manner as in Example 1 except that 0.05 parts by weight of the Pd / C catalyst was added.

The products obtained by the above examples and comparative examples were analyzed and confirmed using nuclear magnetic resonance spectra and gas chromatography-mass spectrometry (GC-MS), and the following conditions and procedures using gas chromatography (GC) Quantitative analysis according to the purity of the paraphenylenediamine (PPD) was measured.

The measurement conditions of the gas chromatography are as follows.

(1) Measuring device: Agilent 6890

(2) Integration: GC Chemstation

(3) Carrier gas: He

(4) Flow: 1.5ml / min

(5) Split ratio: 10: 1 (15ml / min)

(6) Injection concentration: 10wt% SMPL in 99.9% methanol

(7) Colume: Rtx-1701, 30m × 0.32mm × 1.0㎛

(8) Temperature profile: injector 280 ℃, detector 280 ℃, 40 minutes × 140 ℃, 30 ℃ / min to 240 ℃, 20 minutes × 240 ℃

The measurement sequence of the gas chromatography is as follows.

(1) The prepared paraphenylenediamine was completely dissolved in reagent grade methanol having a purity of 99.9% to make a sample of 10 wt%.

(2) The sample is introduced using a syringe, and quantitative analysis is performed under the above-described conditions.

(3) Purity is measured by integrating the peak area of paraphenylenediamine except the methanol peak area in the peak obtained through the above analysis.

The results obtained through the analysis are shown in Table 1 below.

division menstruum catalyst Catalyst amount (part by weight) yield(%) PPD Purity (%) Example 1 n-hexane Pd / C 0.25 97.7 99.8 Example 2 n-heptane Pd / C 0.25 96.9 99.8 Example 3 n-octane Pd / C 0.25 97.1 99.7 Example 4 c-hexane Pd / C 0.25 97.3 99.9 Example 5 c-heptane Pd / C 0.25 96.7 99.9 Example 6 n-hexane Pt / C 0.25 97.2 99.9 Example 7 n-hexane Ru / C 0.25 97.0 99.8 Example 8 n-hexane Rh / C 0.25 96.6 99.7 Example 9 n-hexane Pd / C 4.0 98.0 99.9 Comparative Example 1 n-hexane + water + surfactant Pd / C 0.25 91.3 99.5 Comparative Example 2 Methanol Pd / C 0.25 93.4 99.5 Comparative Example 3 ethanol Pd / C 0.25 93.7 99.4 Comparative Example 4 THF Pd / C 0.25 93.2 99.1 Comparative Example 5 n-hexane Ra-Ni 0.25 91.5 98.6 Comparative Example 6 n-hexane Ra-Ni 5.0 94.5 99.4 Comparative Example 7 n-hexane Pd / C 0.05 94.6 99.3

As shown in Table 1 above, when only an aliphatic hydrocarbon solvent is hydrogenated without addition of water and a surfactant, paraphenylenediamine is prepared than when water and a surfactant are added or a hydrogenation reaction is performed using a polar solvent. It can be seen that the purity and yield of the superior. In addition, in the case of a noble metal catalyst, even if a small amount is used, a sufficient yield and purity can be obtained, but in the case of Raney nickel, even if more than 10 times compared to the noble metal catalyst, it can be seen that the purity and yield are lower than that of the noble metal catalyst.

In addition, when too few precious metal catalysts are added, smooth purity and yield cannot be obtained. On the other hand, when too much precious metal catalysts are added, the purity and yield are not significantly increased. Therefore, the noble metal catalyst may be added in an amount of 0.1 to 4 parts by weight based on 100 parts by weight of paranitroaniline.

2) Preparation of Aramid Polymer and Aramid Fiber

Example  10 to 18

Using each of the paraphenylenediamine prepared by the production method of Examples 1 to 9, it was polymerized with terephthaloyl dichloride to obtain an aramid polymer. Thereafter, the aramid polymer was dissolved in 100% sulfuric acid solvent to prepare a spinning dope. Thereafter, the filament was prepared by spinning the spin dope using a spinneret and then solidifying it in a coagulation bath through an air gap. Subsequently, the filament was washed with water and dried, and then wound up with a winder to obtain aramid fibers.

Comparative example  8 to 14

In Example 10 described above, instead of using the paraphenylenediamine prepared by Example 1, the same as in Example 10 except that each of the paraphenylenediamine prepared by Comparative Examples 1 to 7 are used The aramid fiber was obtained by the method.

The strength of the aramid fibers obtained by the above examples and comparative examples was measured by the following method and the results are shown in Table 2 below.

Tensile Strength Measurement of Aramid Fibers

Tensile strength (g / d) of aramid fibers was measured according to the ASTM D 885 test method.

division Tensile strength (g / d) Example 10 25 Example 11 25 Example 12 23 Example 13 26 Example 14 27 Example 15 26 Example 16 25 Example 17 25 Example 18 28 Comparative Example 8 14 Comparative Example 9 19 Comparative Example 10 18 Comparative Example 11 15 Comparative Example 12 14 Comparative Example 13 19 Comparative Example 14 19

As shown in Table 2 above, the aramid fibers prepared using the high purity paraphenylenediamine prepared by the Example compared to the aramid fibers prepared using the low purity paraphenylenediamine prepared by the Comparative Example It can be seen that the tensile strength is high.

Claims (16)

Preparing para-nitroaniline; And
A method for producing paraphenylenediamine, comprising the step of reacting hydrogen with paranitroaniline using a noble metal catalyst under a hydrocarbon solvent to hydrogenate. The method of claim 1,
The noble metal catalyst is a method for producing paraphenylenediamine containing a Group 8 metal on the periodic table. The method of claim 1,
The noble metal catalyst is a method for producing paraphenylenediamine containing at least one of palladium (Pd), rhodium (Rh), ruthenium (Ru) and platinum (Pt). The method of claim 1,
The noble metal catalyst is a method for producing paraphenylenediamine, characterized in that supported on the carrier. The method of claim 4, wherein
The carrier is a method for producing paraphenylenediamine comprising at least one of carbon, alumina, silica, zirconia, titanium, silicoaluminate, alkaline earth metal, and alkali metal. The method of claim 1,
The hydrogenation step is a method for producing paraphenylenediamine, characterized in that the reaction is carried out in a state that does not contain water. The method of claim 1,
The hydrogenation step is a method for producing paraphenylenediamine, characterized in that the reaction is carried out in a state containing no surfactant. The method of claim 1,
Purity of the paraphenylenediamine produced after the hydrogenation step is 99.6% or more method for producing a paraphenylenediamine. The method of claim 1,
The paraphenylenediamine is para-nitrochlorobenzene, para-nitroaniline, para-chloroaniline, para-chloroaniline, ortho-phenylenediamine, and metaphenylenediamine. -phenylenediamine), and a method for producing paraphenylenediamine, characterized in that it comprises an impurity of any one of (aniline). The method of claim 1,
The hydrocarbon solvent is a method for producing paraphenylenediamine, characterized in that an aliphatic hydrocarbon having 5 to 10 carbon atoms. The method of claim 10,
The hydrocarbon is n-pentane, n-hexane, n-heptane, n-octane, n-nonne, n-nonane nonane, decane, cyclopentane, cyclohexane, cycloheptane, methyl-cyclohexane, 2-ethylhexane ), 2-methylpentane, isopentane, isohexane, isoheptane, and isooctane. A method for producing paraphenylenediamine. The method of claim 1,
The hydrogenation step is a method for producing paraphenylenediamine, characterized in that carried out at a reaction temperature of 20 to 150 ℃. The method of claim 1,
The hydrogenation step is a method for producing paraphenylenediamine, characterized in that carried out at a reaction pressure of 5 to 100 bar (bar). The method of claim 1,
The hydrogenation step is a method for producing paraphenylenediamine, characterized in that using 0.1 to 4 parts by weight of catalyst based on 100 parts by weight of paranitroaniline. The method of claim 1,
The hydrogenation step is a method for producing paraphenylenediamine, characterized in that using 20 to 200 parts by weight of paranitroaniline with respect to 100 parts by weight of hydrocarbon solvent. A polymer prepared by polymerizing para-phenylenediamine prepared by the method of any one of claims 1 to 15 with an aromatic diacid compound.