KR20020046902A - The stable catalyst for hydropurification and the process for purification using the same - Google Patents

Abstract

The present invention relates to a catalyst and purification method for aromatic carbonic acid purification with improved performance, characterized in that the support of 0.1 to 3.0% by weight of palladium and ruthenium on a solid carrier, characterized in that the weight ratio of supported palladium: ruthenium is 0.20 ~ 5.0 An aromatic carbonic acid purification catalyst and a purification method using the same, the catalyst of the present invention is extremely excellent in activity and catalyst stability.

Description

The stable catalyst for hydropurification and the process for purification using the same}

The present invention relates to aromatic carbons based on palladium and ruthenium metals for the purification of aromatic carbonic acids including terephthalic acid used for the synthesis of polyester polymers and copolymers used in the manufacture of fibers and films. It relates to an acid purification catalyst and a purification method using the same.

It is important that the aromatic carbonic acid used as monomer for the production of polymer fibers has a high degree of purity. The main determining parameter of aromatic carbonic acid quality is the content of aromatic aldehydes and colored impurities due to insufficient oxidation, including 4-carboxybenzaldehyde (4-CBA).

Purified aromatic carbonic acid is prepared from less pure, industrial or "crude" aromatic carbonic acid by hydropurification (purification in the presence of hydrogen) on a catalyst comprising Group VIII metals. The crude aromatic aromatic acid is dissolved in water at high temperature, and the resulting solution is hydrogenated in a fixed bed bed reactor, preferably in the presence of a catalyst comprising Group VIII metals. Purification methods, catalysts and methods for making these catalysts are described in a number of patents.

The activity and selection of the catalyst for the hydrotreating purification of aromatic carbonic acid is dependent on the content of the group metal or metals in the catalyst, the supported form, the method used for the support of the group metal or metals, as well as the metal on the support granules. Depend on a number of factors, such as the distribution of metals or metals.

A method for the hydrotreatment of crude aromatic aromatic acids is known from British Patent No. 947769 (1965), wherein the catalyst "palladium on activated carbon" is an aromatic aldehyde impurity such as 4-carboxybenzaldehyde. High activity in the purification reaction of aromatic carbonic acid from the

For more efficient hydrotreatment of aromatic carboxylic acids from aromatic aldehydes, it is important to prepare supported palladium as a catalyst having a certain size [US Pat. No. 4,415,479 (1983); 4,421,676 (1983) and 4,791,226 (1988). These particles must have a size of 35 mm 3 or less. The inventors of US Pat. Nos. 4,394,299 (1983) and 4,791,226 (1988) describe that this distribution of palladium particles in the carbon granules has a positive effect when the palladium particles are heavily distributed on the outer surface of the granules. Doing.

Many patents describe that the introduction of Ni, Co, Cu, Fe, Mn, U, Cr, etc. as well as Ir, Rh, Pt, and Ru with a single metal catalyst can have a positive effect on the catalytic efficiency of palladium. It is.

According to patents such as U.S. Patent Nos. 4,629,715 (1986) and 4,892,972 (1990), the catalysts in the reactor are, for example, Pd / C and Rh instead of one layer of (Rh + Pd) / C. The most effective bimetallic catalyst is achieved when placed in several layers, such as / C. The inventors of US Pat. No. 4,892,972 (1990) have patented a method using a multilayered catalyst such as, for example, Ru / C + Rh / C + Pd / C.

Catalysts, typically palladium catalysts, which typically contain Group VIII metals, are prepared by adsorption of palladium salts from solution onto the carrier. In one of these methods, US Pat. No. 2,857,337 (1967), the salt is treated with a water soluble metal hydroxide or basic carbonate and further treated with a reducing agent such as formaldehyde, glucose, glycerin and the like to reduce to metal palladium.

According to Kite et al. (US Pat. No. 3,138,560 (1967)), upon addition of sodium tetrachloropalladate or palladium chloride to many carbon carriers, most of the palladium is immediately polished metal palladium. It is deposited in the form of a film. Catalysts prepared in this way typically have low activity. Palladium was thought to be directly reduced to the metal, due to the presence of functional groups such as free electrons or aldehydes on the carbon surface. Prior to the reduction step, palladium catalysts are usually prepared by immobilizing palladium in the form of an insoluble compound, which avoids the problems of elution and crystal growth of palladium particles that may occur upon reduction of palladium from solution.

Adjacent purification methods are presented in British Patent No. 1575725 (1980), wherein the inventors have found two, such as Pt, Pd, Rh, Ru, Os, Ir, Fe, Ni, Co, Cr, Mn and U. The use of a catalyst comprising more than two metals has been proposed, where one of these metals is Pd or Pt. In the catalysts described above, the metals are present in the form of alloys, physical mixtures or supported on a carbon carrier, ie activated carbon (3-6 mm granules). Hydrotreating purification is carried out by treating the aromatic carbonic acid solution with hydrogen in the presence of the catalysts mentioned above at high temperature (˜280 ° C.) and high pressure (˜100 atmospheres). In the presence of bimetallic catalyst (0.4% Pd-0.1% Pt) / C the rate of hydrogenation reaction is 20% higher than with 0.5% Pd / C.

Recently, it has been known that the purification of terephthalic acid by mesoporous (mesoporous) and carbon-supported Pd, Pt, Rh and Ru catalysts is possible. [World patent publication No. WO 00108798A1, Catalytic composition, method for manufacturing technology and method for the purification of terephthalic acid, Feb. 8, 2001).

As such, crude aromatic aromatic acid containing aromatic aldehyde such as 4-CBA and other impurities can be purified by hydrogenation by catalysts traditionally prepared on the Group VIII metal supported on carbon.

Nevertheless, the catalyst for hydrorefining has a relatively short lifespan of about one year. Increasing the life of the catalyst is very effective in reducing the cost of the catalyst as well as preventing losses due to plant shutdowns. The present inventors have sought to improve the life of the catalyst.

The present invention is to solve the problems of the prior art as described above, it is an object of the present invention to provide an effective and prolonged aromatic catalyst for purification aromatic aromatic acid supported on palladium and ruthenium and a purification method using the same.

1 is a graph showing the purification activity of terephthalic acid of a hydrogenation purification catalyst (new catalyst) according to the content of Pd and Ru,

Figure 2 is a graph showing the purification activity of terephthalic acid of the hydrogenation purification catalyst (catalyst after deterioration) according to the content of Pd and Ru.

The catalyst for purifying aromatic carbonic acid of the present invention supports 0.1 to 3.0% by weight of palladium (Pd) and ruthenium (Ru) on a solid carrier, and the weight ratio of supported palladium: ruthenium is 1: 0.2 to 5.0. It is characterized by that.

As described above, the catalyst for purification of aromatic carbonic acid of the present invention preferably supports 0.1 to 3.0% by weight of palladium (Pd) and ruthenium (Ru) on a solid carrier, and less than 0.1% by weight. If supported, the catalytic performance is poor, and if it is more than 3.0% by weight, the economic efficiency is poor, which is not preferable. In addition, the weight ratio of the supported palladium: ruthenium is preferably 1: 0.2 to 5.0, and when the weight ratio is less than 1: 0.2, the catalytic performance is weak, and when the weight ratio is greater than 1: 5.0, it is the same as the existing palladium or ruthenium catalyst to improve catalytic activity. It is not preferable because there is no effect of improving performance.

In the catalyst for purification of aromatic carbonic acid of the present invention, the weight ratio of the supported palladium: ruthenium is particularly preferably 1: 0.40 to 2.50, and the solid carrier may be any solid carrier available, but carbon is preferred. The carbonaceous material has mesopore with an average size of 40-400 mm 3, mesopore volume of 0.5 or more in total pore volume, and mesoporous graphite-like material having a medium porosity of 20% or more. Can be.

In the aromatic carbonic acid purification catalyst of the present invention, the crystals of palladium and ruthenium are distributed such that a layer exists in a bulk of the carbonaceous granule at a distance corresponding to 1 to 30% of its radius from the outer surface of the granule. It is desirable to have.

The catalyst for purification of aromatic carbonic acid of the present invention can be used for purification of terephthalic acid, particularly among aromatic carbonic acid.

The catalyst described above is prepared using, but not limited to, one of the following metal precursors;

H ₂ PdCl ₄ , PdCl ₂ or Pd (NO ₃ ) ₂ ; RuCl ₃ , RuCl ₃ hydrate, RuOHCl ₃ or RuNO (NO ₃ ) ₃ .

The present inventors can ascertain the catalyst composition having superior properties after deterioration of the catalyst as well as the properties of which the activity is improved compared to the composition of the catalyst in the appropriate distribution of the palladium and ruthenium catalysts supported on carbon, resulting in catalyst cost. Not only is this lower (because ruthenium is cheaper than palladium and synergistic with palladium), it has also been found that activity and stability can be improved, resulting in higher quality aromatic carbonic acid.

In order to prepare the catalysts, that is, catalysts comprising bimetallic particles of palladium and ruthenium supported on a carbon carrier, a method well known in the literature, namely, infiltration of a solution of various salts of Pd and Ru into the carrier, The same methods can be used. Wet impregnation and dry impregnation may be used for supporting the metal compound, and a spraying method may be effectively used during vapor phase support. After supporting the metal compound, the metal compound component may be reduced by an aldehyde component or free electrons of the carbon carrier, and may be hydrogen, formaldehyde, hydrazine, sodium formate, glucose, sodium hypophosphite reduction with a reducing agent such as hypophosphite) may be further carried out. Gas phase reduction with hydrogen and liquid phase reduction with aqueous sodium hypophosphite solution can be used effectively. The best catalyst is prepared when spraying acid salts of Pd and Ru on a suitable carbon carrier and further treating the supported metal precursors with hydrogen. The catalyst can be prepared without further reduction treatment after the support of the metal compound, in which case it has the simplest features of the process.

Purifying aromatic carbonic acid of the present invention is carried out in a conventional manner using the catalyst.

The examples given below illustrate catalysts and methods for their preparation, but the invention is not limited thereto.

Example 1

The catalyst was prepared similarly to the method of Example 3 of International Patent Publication No. WO 00108798A1 ("Catalyst composition, preparation, purification method for purification of terephthalic acid") and had a composition of 0.3% Pd-0.2% Ru / Sibunit. . In other words, Sibunit (VA Likholobov et al., React. Kin. Cat. Lett., V.54, 2 (1995) 381-411), a 20 g carbon carrier, boiled in distilled water and purified and dried from dust in advance. Was placed in a cylindrical rotary reactor. 0.3M of PdCl ₂ (dissolved in HCl solution) was added 0.25M and 1.88cc of RuCl ₃ (dissolved in HCl solution) was 1.58cc and containing distilled water 1.44cc the dice of 0.6M Na ₂ CO ₃ 3.2cc and 1.7cc of distilled water Was put in another die and sprayed simultaneously on the carbon carrier at a rate of 1 cc / min. Spraying was performed using flowing air, and the carbon carrier during the spraying was rotated at 60-80 rpm. The supported catalyst was vacuum dried at 70 ° C. and then heated to 250 ° C. over 1.5 hours, at which temperature it was reduced by keeping in hydrogen flow in a tubular reactor for 2 hours. After cooling, the catalyst was washed with distilled water and continued until the reaction of chlorine ions with AgNO ₃ disappeared. After drying in vacuo at 70 ° C., the initial activity of the catalyst and the activity after degradation were measured. It was assumed that terephthalic acid containing 3% 4-CBA was hydrogenated and purified at 250 ° C. for 5 to 30 minutes using a prepared catalyst. Rate constants were obtained by analyzing the 4-CBA concentration with each reaction time.

Degradation proceeded similarly to the method of Korean Patent Application No. 2000-32736 ("Fast Aging Method of Hydrogen Purification Catalyst"). That is, four types of catalysts were simultaneously maintained for 44 hours under conditions in which 4-CBA and hydrogen were present to deteriorate.

The rate constants after initial and deterioration of the obtained catalyst are 0.119 / min and 0.116 / min, respectively, and are arithmetically calculated from the rate constants obtained in Comparative Examples 1 and 2 described later, that is, 0.5% Pd / sieve unit and 0.5% Ru / sieve unit. Compared to the rate constants of 0.094 / min and 0.053 / min, the activity was 127.2% and 217.3%, respectively. Therefore, both the initial activity and the activity after deterioration were improved, so that palladium and ruthenium were synergistic in the catalytic activity. You can see it. Detailed values such as reaction rate constants and calculated values of Examples 1 to 6 and Comparative Examples 1 to 4 are shown in Table 1 and FIGS. 1 and 2.

Example 2

A catalyst having a composition of 0.2% Pd-0.3% Ru / sieve unit was prepared by adjusting the amount of metal salt and Na ₂ CO ₃ similarly to Example 1, and then the activity after initial and deterioration was analyzed similarly to Example 1. It was.

The rate constants after initial and deterioration of the catalyst obtained are 0.098 / min and 0.069 / min, respectively, and are calculated arithmetically in the rate constants obtained in Comparative Examples 1 and 2, that is, 0.5% Pd / sieve unit and 0.5% Ru / sieve unit. Compared to the constant 0.071 / min and 0.040 / min, it shows 138.1% and 173.3% of activity, respectively. Therefore, both the initial activity and the activity after deterioration are improved, indicating that palladium and ruthenium show synergy in catalytic activity. .

Example 3

A catalyst having a composition of 0.15% Pd-0.35% Ru / sieve unit was prepared by adjusting the amount of metal salt and Na ₂ CO ₃ similarly to Example 1, and then the activity after initial and deterioration was analyzed similarly to Example 1 It was.

The initial rate constant of the catalyst obtained was 0.088 / min, which was 147.5% compared to the rate constant 0.059 / min calculated arithmetically in the rate constants obtained in Comparative Examples 1 and 2, namely 0.5% Pd / sieve unit and 0.5% Ru / sieve unit. It can be seen that the activity of, so that palladium and ruthenium shows synergy in the catalytic activity.

Example 4

A catalyst having a composition of 0.256% Pd-0.244% Ru / sieve unit was prepared by adjusting the amount of the metal salt and Na ₂ CO ₃ similarly to Example 1, and then the initial and deterioration activities were analyzed similarly to Example 1 It was.

The initial rate constant of the catalyst obtained was 0.104 / min and was 124.3% compared to the rate constant 0.084 / min calculated arithmetically in the rate constants obtained in Comparative Examples 1 and 2, namely 0.5% Pd / sieve unit and 0.5% Ru / sieve unit. It can be seen that the activity, and therefore palladium and ruthenium shows synergy in the catalytic activity.

Example 5

A catalyst having a composition of 0.4% Pd-0.1% Ru / sieve unit was prepared by adjusting the amount of metal salt and Na ₂ CO ₃ similarly to Example 1, and then the activity after initial and deterioration was analyzed similarly to Example 1. It was.

The rate constants after initial and deterioration of the catalyst obtained are 0.101 / min and 0.095 / min, respectively, and are calculated arithmetically by the rate constants obtained in Comparative Examples 1 and 2, that is, 0.5% Pd / sieve unit and 0.5% Ru / sieve unit. It can be seen that the activity is 87.0% and 141.6%, respectively, compared to the constant 0.116 / min and 0.067 / min. Therefore, the initial activity is slightly inferior but the activity after degradation is improved, so that palladium and ruthenium are synergistic in the catalytic activity after degradation. You can see it.

Example 6

A catalyst having a composition of 0.1% Pd-0.4% Ru / sieve unit was prepared by adjusting the amount of metal salt and Na ₂ CO ₃ similarly to Example 1, and then the activity after initial and deterioration was analyzed similarly to Example 1. It was.

Rate constants after initial and deterioration of the obtained catalyst were 0.044 / min and 0.042 / min, respectively, and the rate constants arithmetically calculated from the rate constants obtained in Comparative Examples 1 and 2, that is, 0.5% Pd / sieve unit and 0.5% Ru / sieve unit It can be seen that the activity is 91.8% and 161.5%, respectively, compared to 0.048 / min and 0.026 / min. Therefore, the initial activity is slightly inferior, but the activity after degradation is improved, so that palladium and ruthenium show synergy in catalytic activity after degradation. It can be seen.

Comparative Example 1

A catalyst having a composition of 0.5% Pd / sieve unit was prepared by adjusting the amount of metal salt and Na ₂ CO ₃ similarly to Example 1, and then the activity after initial and deterioration was analyzed similarly to Example 1.

The rate constants of the catalyst obtained after initial and deterioration are 0.139 / min and 0.081 / min, respectively, and the initial activity is relatively high, but the catalyst activity after deterioration decreases to 58% of the initial activity and is lower than Example 1, resulting in low stability of the catalyst. It can be seen.

Comparative Example 2

A catalyst having a composition of 0.5% Ru / sieve unit was prepared by adjusting the amount of metal salt and Na ₂ CO ₃ similarly to Example 1, and then the activity after initial and deterioration was analyzed similarly to Example 1.

The rate constants of the obtained catalysts after initial and deterioration are 0.025 / min and 0.012 / min, respectively, and the initial activity and the catalytic activity after deterioration are very low, and the characteristics of the catalyst are very poor. In particular, the activity after deterioration is significantly lower in stability as compared to the initial activity 48%.

Comparative Example 3

A catalyst having a composition of 0.45% Pd-0.05% Ru / sieve unit was prepared by adjusting the amount of metal salt and Na ₂ CO _{3 in} a similar manner to Example 1, and the activity after initial and deterioration was analyzed similarly to Example 1 It was.

The rate constants after initial and deterioration of the obtained catalyst are 0.120 / min and 0.077 / min, respectively, and are calculated arithmetically by the rate constants obtained in Comparative Examples 1 and 2, that is, 0.5% Pd / sieve unit and 0.5% Ru / sieve unit. It can be seen that the activity is 93.9% and 104.1%, respectively, compared to the constant 0.127 / min and 0.074 / min. Thus, the catalyst having a composition of 0.45% Pd-0.05% Ru / sieve unit has a particular improvement in initial activity and activity after deterioration. It wasn't.

Comparative Example 4

A catalyst having a composition of 0.05% Pd-0.45% Ru / sieve unit was prepared by adjusting the amount of metal salt and Na ₂ CO ₃ similarly to Example 1, and then the activity after initial and deterioration was analyzed similarly to Example 1. It was.

The rate constants after initial and deterioration of the catalysts obtained were 0.036 / min and 0.018 / min, respectively, and were calculated arithmetically in the rate constants obtained in Comparative Examples 1 and 2, namely, 0.5% Pd / sieve unit and 0.5% Ru / sieve unit. It can be seen that the activity of 97.2% and 94.0%, respectively, compared to the constant 0.037 / min and 0.019 / min, so that the catalyst having a composition of 0.05% Pd-0.45% Ru / sieve unit has a particular improvement in initial activity and activity after deterioration. It wasn't.

Table 1 . Composition of catalyst, initial rate constant, rate constant after degradation and rate constant ratio

Pd (%) Ru (%) New catalyst Deteriorated catalyst K * (calculated value) K * (measured value) ratio(%)** K * (calculated value) K * (measured value) ratio(%)** Example 1 0.30 0.20 0.094 0.119 127.2 0.053 0.116 217.3 Example 2 0.20 0.30 0.071 0.098 138.1 0.040 0.069 173.3 Example 3 0.15 0.35 0.059 0.088 147.5 0.033 - - Example 4 0.256 0.244 0.084 0.104 124.3 0.047 - - Example 5 0.40 0.10 0.116 0.101 87.0 0.067 0.095 141.6 Example 6 0.10 0.40 0.048 0.044 91.8 0.026 0.042 161.5 Comparative Example 1 0.50 0.00 0.139 0.139 100.0 0.081 0.081 100.0 Comparative Example 2 0.00 0.50 0.025 0.025 100.0 0.012 0.012 100.0 Comparative Example 3 0.45 0.05 0.127 0.120 93.9 .074 0.077 104.1 Comparative Example 4 0.05 0.45 0.037 0.036 97.2 0.019 0.018 94.0

*: First order rate constant (/ min), calculated from rate constants and compositions of 0.5% Pd / sieve unit and 0.5% Ru / sieve unit.

**: The ratio of K (measured) / K (calculated).

As can be seen from the above, the aromatic carbonic acid purification catalyst of the present invention has excellent activity and extremely excellent catalyst stability.

Claims (12)

A catalyst for purifying aromatic carbonic acid, characterized in that palladium and ruthenium are supported in a total amount of 0.1 to 3.0% by weight, and the weight ratio of supported palladium: ruthenium is 1: 0.2 to 5.0. The catalyst for purification of aromatic carbonic acid according to claim 1, wherein the weight ratio of palladium: ruthenium is 1: 0.4 to 2.5. The catalyst for purification of aromatic carbonic acid according to claim 1, wherein the carrier is carbon. The method of claim 3, wherein the carbon material has a mesopore of average size of 40 ~ 400Å, the mesopore volume of the total pore volume of 0.5 or more, the medium porosity of the graphite-like degree of 20% or more (mesoporous ) A catalyst for refining aromatic carbonic acid, characterized in that the graphite-like material. The method of claim 1, wherein the crystals of palladium and ruthenium are distributed in the bulk of the carbon material granules such that the layer exists within a distance corresponding to 1 to 30% of its radius from the outer surface of the granules. Aromatic carbonic acid purification catalyst. The catalyst for purification of aromatic carbonic acid according to any one of claims 1 to 5, wherein the palladium and ruthenium compounds are supported by a spraying method. The method according to any one of claims 1 to 5, wherein after supporting the palladium and ruthenium compounds, hydrogen, formaldehyde, hydrazine, sodium formate, glucose, or sodium hypophosphite as a reducing agent A catalyst for the purification of aromatic carbonic acid, characterized in that prepared by further reducing by hypophosphite). The method according to claim 6, after supporting the palladium and ruthenium compounds, further by hydrogen, formaldehyde, hydrazine, sodium formate, glucose, or sodium hypophosphite as a reducing agent. Catalyst for purification of aromatic carbonic acid, characterized in that prepared by reducing. The catalyst for purification of aromatic carbonic acid according to any one of claims 1 to 5, wherein the catalyst is prepared without further reduction after supporting the palladium and ruthenium compounds. The catalyst for purifying aromatic carbonic acid according to claim 6, wherein the catalyst is prepared without further reduction after supporting the palladium and ruthenium compounds. The catalyst for purification of aromatic carbonic acid according to claim 1, wherein the aromatic carbonic acid is terephthalic acid. A method for purifying aromatic carbonic acid using the catalyst according to any one of claims 1 to 11.