KR101057636B1 - Isomerization catalyst of dimethylnaphthalene and using the same - Google Patents

Abstract

The present invention provides a Group VIII metal comprising ruthenium in a mixed carrier of a mordenite zeolite having a molar ratio of silica / alumina of 10 to 200 and an inorganic binder selected from silica, alumina, and the like, and tin, lead, bismuth, and rhenium. It provides a binary metal catalyst carrying at least one second metal selected from iridium, antimony, and 2,6-dimethylnaphthalene through gas phase isomerization of dimethylnaphthalene using a catalyst prepared according to the present invention. In the case of using the catalyst of the present invention, the dimethyl naphthalene isomers present in the alkylnaphthalene mixture compared to the conventional catalyst, while minimizing the loss of reactants due to hydrocracking / dealkylation, etc., 2,6- Converted to dimethylnaphthalene, and the degree of catalyst deactivation was greatly improved

Dimethylnaphthalene (DMN), gas phase isomerization reaction, binary metal catalyst

Description

Isomerization catalyst of dimethylnaphthalene and vapor phase isomerization method of dimethylnaphthalene using the same {Process and Catalyst for Isomerizing Dimethylnaphthalene in Gas Phase}             

1 is a graph showing the yield of 2,6-dimethylnaphthalene over reaction time in the isomerization of dimethylnaphthalene using the catalyst of the present invention and a conventional catalyst.

The present invention relates to an isomerization catalyst of dimethylnaphthalene and an isomerization reaction of dimethylnaphthalene using the same. More specifically, a method for producing 2,6-dimethylnaphthalene in the presence of a catalyst supported with a binary metal in the gas phase It is about.

Polyethylene naphthalate resin has better properties in many aspects such as mechanical strength, thermal and chemical stability than polyethylene terephthalate resin, which is widely commercially available today, and thus it is a potential resin to replace polyethylene terephthalate in the future. It is expected polyester. Polyethylene naphthalate has a naphthalene ring as the backbone, and 2,6-naphthalene dicarboxylate made from 2,6-dimethylnaphthalene is the monomer. Therefore, the economical efficiency of polyethylene naphthalate is determined by the efficient and economic production of 2,6-dimethylnaphthalene, and attention is focused on the preparation of 2,6-dimethylnaphthalene through various methods.

In the prior art, a method for preparing 2,6-dimethylnaphthalene through isomerization of dimethylnaphthalene has been proposed, of which high-purity 1,5-dimethylnaphthalene belonging to the 3,6-dimethylnaphthalene 3 compound It is known to use 1,6-dimethylnaphthalene as a starting material and an alkylnaphthalene fraction containing up to 10 mixtures of dimethylnaphthalene isomers as a starting material.

The preparation of certain dimethylnaphthalene isomers, such as pure 1,5-dimethylnaphthalene or 1,6-dimethylnaphthalene, begins with the preparation of mono alkenylated aromatics as set forth in US Pat. No. 4,990,717 or 5,118,892. . This known method of preparing dimethyl naphthalene has the disadvantage of being expensive due to the limitation of using a relatively expensive starting material and a base catalyst, but has the advantage of high yield of isomerization reaction and easy separation and purification problems.

In contrast, the light cycle oil produced from the heavy oil decomposition process contains abundant alkylnaphthalenes including naphthalene, monoalkylnaphthalene, dimethylnaphthalene and trimethylnaphthalene. The dimethyl naphthalene isomer mixture may be separated through a purification process such as crystallization and adsorptive separation of the fractions already contained in the fraction, or may be produced through a process such as disproportionation, transalkylation, and dealkylation of the alkylnaphthalene mixture. In this case, it is more economical in terms of supply of the raw material for isomerization reaction, but since all 10 isomers participate in the isomerization reaction, there is a problem due to the reactivity of other alkylnaphthalene except dimethylnaphthalene.

Isomerization of dimethylnaphthalene has been mainly used for solid acid catalysts such as mordenite, beta zeolite, Y zeolite and ZSM-5, and the reaction is mainly carried out in liquid phase at 260 ~ 270 ^o C close to the boiling point of dimethylnaphthalene. Is common. (See US Pat. Nos. 4,041,089, 3,888,938, 4,962,260)

The reason why the conventional liquid phase isomerization reaction is proposed in the prior art is that when the reaction proceeds in the gas phase, low yield of 2,6-dimethylnaphthalene, acceleration of deactivation of the catalyst, and side reaction control are problematic. Accordingly, economic methods have been studied to solve the problem of gas phase reaction.                         

U.S. Pat.Nos. 6,121,501 and 5,744,670 describe the preparation of 2,6-dimethylnaphthalene under MCM-22 catalyst using dimethylnaphthalene isomeric mixtures as reactants. According to the patent, as a result of the reaction, about 20% by weight of dimethylnaphthalene was incidentally converted to monomethylnaphthalene, naphthalene, and the like. U.S. Patent No. 4,783,569 discloses a method for isomerizing dimethylnaphthalene through a gas phase reaction using a synthetic borosilicate catalyst.

On the other hand a high when the temperature is the isomerization reaction occurring in, mordenite zeolites to improve the yield degradation problems of the disproportionation U.S. Patent No. 5,481,055 No. (normal pressure) of the 150 by the addition of an aromatic solvent such as benzene, ^o C occurs at the same time as the catalyst One method for preparing 2,6-dimethylnaphthalene through a gas phase reaction is presented.

U. S. Patent No. 3,806, 552 describes a gas phase isomerization reaction catalyzed by a mixture of mordenite and bentonite in which metal ions are substituted in hydrogen form. In addition, US Pat. No. 5,004,853 describes a method for preparing 2,6-dimethylnaphthalene through gas phase isomerization under a mordenite catalyst carrying about 0.1 to 2% by weight of platinum group catalyst. However, the platinum group metal has a strong hydrogenation function, which inevitably causes hydrogenation and hydrocracking of dimethylnaphthalene, which greatly reduces the yield of dimethylnaphthalene.

SUMMARY OF THE INVENTION An object of the present invention is to provide an isomerization catalyst in gas phase isomerization reaction of dimethylnaphthalene, which minimizes the loss of dimethylnaphthalene fraction by hydrogenation and hydrolysis to increase the yield and reduce the deactivation of the catalyst.

Another object of the present invention is to provide a method for producing 2,6-dimethylnaphthalene by vapor phase isomerization of dimethylnaphthalene using such an isomerization catalyst.

According to the invention,

10 to 95% by weight of zeolite having a silica / alumina mole ratio of 10 to 200;

5 to 90% by weight of at least one inorganic binder selected from the group consisting of gamma alumina, silica and silica alumina; And

A vapor phase carrying 0.01 to 5 parts by weight of at least one second metal selected from 0.001 to 10 parts by weight of a Group VIII metal and tin, lead, bismuth, rhenium, iridium, and antimony based on 100 parts by weight of the mixed carrier of the zeolite and the inorganic binder. Isomerized binary metal catalysts are provided.

In addition, according to the present invention,

10 to 95% by weight of zeolite having a silica / alumina mole ratio of 10 to 200;

5 to 90% by weight of at least one inorganic binder selected from the group consisting of gamma alumina, silica and silica alumina; And

A vapor phase containing 0.01 to 5 parts by weight of at least one second metal selected from 0.001 to 10 parts by weight of a Group VIII metal and tin, lead, bismuth, rhenium, iridium, and antimony based on 100 parts by weight of the mixed carrier of the zeolite and the inorganic binder. Provided is a method of isomerizing dimethylnaphthalene to 2,6-dimethylnaphthalene using an isomerized binary metal catalyst.

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

As described above, in order to prepare 2,6-dimethylnaphthalene through the gas phase isomerization of dimethylnaphthalene-rich alkylnaphthalene mixed fraction according to the present invention, the loss of dimethylnaphthalene by hydrogenation and hydrolysis is minimized. While providing a catalyst carrying a binary metal to prevent the deactivation of the catalyst.

The zeolite used in the present invention is a zeolite having a pore size of more than 5Å of the pore size, and includes zeolites in the form of FAU, MOR, and BEA structures, and specifically, zeolite beta, mordenite, Y zeolite may be used. Preferably mordenite is mentioned. In the present invention, a silica / alumina molar ratio of 10 to 200, preferably 50 or more, and an ion-exchanged form in ammonium or hydrogen form was used.

The zeolites should be mixed with at least one inorganic binder, and the inorganic binder used in the present invention is selected from the group consisting of gamma alumina, silica, silica-alumina, and amorphous oxides of gamma alumina and silica are preferred. When the inorganic binder and the zeolite are combined, the mixture is mixed so that the weight ratio of the zeolite is 10 to 95% by weight, preferably 50 to 80% by weight, and then extruded to form an extrudate. Mold 2 mm in diameter and 5 to 15 mm in length.

The zeolite catalyst used in the isomerization reaction preferably comprises a metal having at least one hydrogenation function. Examples of such metals include oxides of Group VIII metals including platinum, palladium, rhodium, ruthenium, and the like, and hydrates. Ruthenium in which the valence state of the metal is reduced is preferable. In order to control the hydrocracking function of alkylnaphthalene by the hydrogenation of these Group VIII metals, additional metal components may be supported on zeolites. Examples of such second metals include Group VIII metals and Groups IVA, VA and VIIB metals. And oxides and hydrates thereof. Specific examples thereof include tin, lead, bismuth, rhenium, iridium, and antimony. Of these, tin is most preferred.

The amount of metal present in the zeolite catalyst is generally from about 0.001 to about 10 parts by weight, preferably 0.005 to 0.1 parts by weight, for 100 parts by weight of the mixture of zeolite and inorganic binder, for a Group VIII metal having a hydrogenation function. Preferably, the second metal for adjusting the hydrogenation function of the Group VIII metal is about 0.01 to 5 parts by weight, preferably 0.05 to 1 part by weight. When the amount of the Group VIII metal is more than 10 parts by weight based on 100 parts by weight of the mixture of zeolite and the inorganic binder, dealkylation and hydrocracking reaction tend to increase, and when it is less than 0.001 parts by weight, the deactivation rate of the catalyst increases. Problems may arise. If less than 0.01 parts by weight of the second metal, the function of the Group VIII metal is not properly controlled to increase the loss of alkylnaphthalene, while if more than 5 parts by weight, the function of the Group VIII metal is too weak to deactivate Can lead to an increase.

As the metal introduction method supported on the mixed carrier of the zeolite and the inorganic binder, any ion exchange, impregnation, or physical mixing method can be used, and when introduced into the mixed carrier of the zeolite and the inorganic binder of these metal components, There is no great relationship and two metals may be introduced at the same time, but the metals are preferably present in a properly bonded state.

In the case of gas phase isomerization using the catalyst of the present invention, heavy naphtha (HCN) produced when the atmospheric residue oil supplied from the oil refining process is added to the fluidized catalytic cracking process. Alkali naphthalene mixtures separated from Naphtha) and Light Cycle Oil (LCO), Heavy Reformate produced through the catalytic reforming process are used as reactants.

The separated alkylnaphthalene mixture may be used as a reactant containing dimethylnaphthalene fraction of 50% by weight or more, preferably 70% by weight or more through vacuum distillation, and finally, 2,6-die after recrystallization or adsorptive separation. By removal of methylnaphthalene, less than 20% by weight, preferably less than 10% by weight, of 2,6-dimethylnaphthalene lean fraction, including 2,6-dimethylnaphthalene, relative to the total dimethylnaphthalene fraction can be used as reactant.

The gas phase isomerization reaction condition using the prepared catalyst includes a temperature of 100 ^° C. to 500 ^° C., preferably 200 to 400 ^° C., and a pressure range of 0 to 1000 psig, preferably 100 to 500 psig. . The feed space velocity of the reactants may be from 0.1 to 20 h ⁻¹ , preferably from 1 to 10 h ⁻¹ and the molar ratio of hydrogen to reactant is from 1:20 to 20: 1, preferably from 1:10 to 10: If 1, isomerization of dimethylnaphthalene is achieved.

The reactor used for this gas phase isomerization reaction can use any known reactor used for gas phase continuous reaction. For example, a tubular reactor may be used in which the reactants flow downward in the fixed bed of the catalyst.

As described above, in the preparation of 2,6-dimethylnaphthalene, the present invention reduces gaseous dimethyl without deactivation while reducing the loss of dimethylnaphthalene mixture to 2 wt% or less on the bimetallic catalyst prepared according to the present invention. Naphthalene isomerization reaction was performed.

Hereinafter, the present invention will be described in more detail with reference to the following examples, which do not limit the scope of the present invention.

Example

Example 1

Preparation of Binary Metal Zeolites

Ruthenium prepared by mixing 75 g of a mordenite zeolite (MOR90 from Sud-Chemie: Silica / alumina molar ratio 90 from Sud-Chemie) and 25 g of hydrated alumina (Pural SB from Condea) in a cation of NH ₄ ^+. -The tin metal precursor mixed solution was weighed, kneaded and molded into a 5 mm long extrudate.

After the catalyst was molded, it was dried for 1 day at room temperature, and then heated at a rate of 2 ° C./min in a muffle furnace, dried at 120 ° C. for 3 hours, and then heated to 500 ° C. at the same rate, and calcined for 2 hours. A metal supported zeolite catalyst was prepared. The prepared catalyst contains 0.01 parts by weight of ruthenium and 0.3 parts by weight of tin with respect to 100 parts by weight of the mixture of zeolite and inorganic binder.

Preparation of 2,6-dimethylnaphthalene through isomerization reaction

The reactants were distilled under reduced pressure of the alkylnaphthalenes separated from the heavy reformate produced through the catalytic reforming process to obtain an oil of about 80% of dimethylnaphthalene fraction, followed by recrystallization and finally 2,6-dimethylnaphthalene. The removal of gave 2,6-dimethylnaphthalene lean fraction containing 2,6-dimethylnaphthalene, which is about 6-7% of the total dimethylnaphthalene fraction.

After filling 1 g of catalyst into a reactor of 1/2 inch inner diameter, 45 cm length, stainless steel tubular fixed bed reactor, hydrogen was flowed at 45 cc / min, and then reduced at 400 ° C. at a temperature rising rate of 2 ° C./min for 1 hour. After stabilization at 300 ° C. and 350 psig, the reaction was carried out under the conditions of space velocity (WHSV) = 1.2 h ⁻¹ and H ₂ / reactant ratio = 4.8. The product was sampled every 4 or 8 hours and analyzed on an HP 5890 series GC equipped with a PONA 50 m column from Hewlett Packard, USA. The composition of the reactants and the product is shown in Table 1 below.

TABLE 1

Before the reaction After reaction (TOS, h) Ingredient (% by weight) 20 hours 44 hours 64 hours BTX 0 4.40 2.68 2.08 naphthalene 0 0.45 0.19 0 Monomethylnaphthalene 3.73 5.84 4.62 4.33 Ethylnaphthalene 5.52 6.73 7.29 7.24 Dimethylnaphthalene 79.14 74.82 80.64 80.82 2,6-dimethylnaphthalene ^* 7.10 15.20 14.10 13.20 2,7-dimethylnaphthalene ^* 10.70 15.80 14.60 14.00 Trimethylnaphthalene 4.51 5.05 2.22 2.71 Other ingredients 7.10 2.70 2.36 2.82 evaluation Dimethylnaphthalene Loss (%) - 5.47 -1.89 -2.22 2,6-dimethylnaphthalene yield ^** 5.62 11.37 11.37 10.67 2,6 / 2,7 Dimethylnaphthalene Ratio 0.96 0.97 0.94

^* Weight ratio for each isomer based on 100% dimethylnaphthalene isomer mixture.

^** 2,6-dimethylnaphthalene yield: 2,6-dimethylnaphthalene weight ratio to the total weight of the reactants.

<Example 2>

A mordenite catalyst carrying 0.02 parts by weight of ruthenium and 0.3 parts by weight of tin was prepared in the same manner as in Example 1 with respect to 100 parts by weight of a mixture of zeolite and an inorganic binder to give isomerization of dimethylnaphthalene under the same reaction conditions as in Example 1. The reaction was carried out. The composition of the reactants and the product is shown in Table 2 below.

TABLE 2

Before the reaction After reaction (TOS, h) Ingredient (% by weight) 20 hours 64 hours 88 hours BTX 0 4.57 3.34 2.88 naphthalene 0.03 0.46 0.25 0.19 Monomethylnaphthalene 2.86 5.11 3.85 3.54 Ethylnaphthalene 8.29 7.62 8.36 8.40 Dimethylnaphthalene 80.69 74.54 77.87 78.51 2,6-dimethylnaphthalene 6.50 15.10 14.50 14.00 2,7-dimethylnaphthalene 10.40 16.20 15.70 15.10 Trimethylnaphthalene 1.42 4.34 3.34 3.11 Other ingredients 6.70 3.37 2.99 3.37 evaluation Dimethylnaphthalene Loss (%) 7.53 3.50 2.71 2,6-dimethylnaphthalene yield 11.12 11.26 10.99 2,6 / 2,7 Dimethylnaphthalene Ratio 0.93 0.91 0.93

Comparative Example 1

Dimethylnaphthalene Isomerization on Metal-Free Mordenite Catalysts

The mixture is mixed with 75 g of a mordenite zeolite (MOR90 from Sud-Chemie: molar ratio of silica / alumina from Sud-Chemie 90) in a form of NH ₄ ⁺ and 25 g of hydrated alumina (Pural SB from Condea), followed by a small amount of 1% nitric acid solution. To form a 5 mm diameter extrudate.

The catalyst was dried at room temperature for one day, heated at a rate of 2 ° C./min in muffle, dried at 120 ° C. for 3 hours, heated to 500 ° C. at the same rate, and calcined for 3 hours, and then introduced into the reaction. The prepared catalyst was prepared in the same manner as in Example 1 to perform an isomerization reaction under the same conditions and to compare the stability of the catalyst. The yield of 2,6-dimethylnaphthalene over time is shown in FIG. 1.

Comparative Example 2

Comparison of Dimethylnaphthalene Isomerization Reactivity on Mordenite Catalysts Supported with Various Metals

The platinum, palladium, and ruthenium precursor mixed solution prepared by dissolving a cation in the form of NH ₄ ⁺ (MOR90 from Zeolyst, USA) in water or nitric acid solution was weighed and kneaded to form a 5 mm diameter extrudate. Platinum used H ₂ PtCl ₆ .xH ₂ O, palladium as Pd (NH ₃ ) ₄ Cl ₂ .H ₂ O, and Ru as RuCl ₃ or acetylacetonate as precursors. 1 g of the formed metal-supported catalyst was charged in a SUS tubular fixed bed reactor having a diameter of 1/2 "and a length of 45 cm, dried at 150 ° C. for 1 hour while flowing H ₂ at 30 cc / min, followed by reduction at 400 ° C. for 2 hours. The reaction was carried out at 30 kgf / cm ^{2 at a rate} of H ₂ 14 cc / min and the reactant at a rate of 0.02 cc / min.

[Table 3]

Supported Metal Components platinum platinum Palladium ruthenium Support amount (part by weight) 0.1 0.05 0.05 0.05 Reaction time Before the reaction 16 hours 20 hours Dimethylnaphthalene 78.55 6.84 35.02 23.62 72.53 2,6-dimethylnaphthalene 6.90 14.53 15.75 14.45 14.53 2,7-dimethylnaphthalene 10.90 16.48 16.85 16.46 15.35 evaluation Dimethylnaphthalene Loss (%) - 91.29 55.42 69.93 7.66 2,6-dimethylnaphthalene yield - 0.99 5.52 3.41 10.54 2,6 / 2,7 Dimethylnaphthalene Ratio 0.63 0.88 0.93 0.88 0.95

As described through the above examples and comparative examples, the catalyst prepared according to the present invention is a catalyst deactivation and controlling the hydrocracking action in the gas phase isomerization reaction using a mixture of dimethylnaphthalene isomers present in the alkylnaphthalene mixture as a reactant. It has been found to reduce dimethylnaphthalene loss. The mordenite catalyst loaded with ruthenium and tin at the same time was excellent in suppressing the deactivation of the catalyst as shown in FIG. 1. In addition, as shown in Comparative Example 1 and Comparative Example 2, it was found that the metal-free catalyst promoted the deactivation. When only one platinum group catalyst was supported, it was found that dimethylnaphthalene was reduced in spite of a small amount of support due to high hydrogenation reactivity. It was confirmed that the loss is large. Therefore, the binary metal catalyst proposed in the present invention prevents catalyst deactivation while maintaining isomerization reactivity despite the metal loading of 1/10 or less of the platinum group catalyst supported by the gas phase isomerization catalyst in the prior art, and prevents dimethyl naphthalene. It can be usefully used as a catalyst for reducing the loss of.

The bimetallic catalyst prepared according to the present invention prevents the deactivation of the catalyst while maintaining the isomerization reactivity despite the metal loading of 1/10 or less of the platinum group catalyst supported by the gas phase isomerization catalyst. Reduces the loss.

Claims (18)

10-95% by weight zeolite with a silica / alumina mole ratio of 10-200; 5-90% by weight of at least one inorganic binder selected from the group consisting of gamma alumina, silica, silica-alumina; And 0.01 to 5 parts by weight of at least one second metal selected from 0.001 to 10 parts by weight of a Group VIII metal and tin, lead, bismuth, rhenium, iridium and antimony based on 100 parts by weight of the mixed carrier of the zeolite and the inorganic binder Gas phase isomerization binary metal catalyst of methylnaphthalene. The method of claim 1, wherein the zeolite is beta zeolite, mordenite, or Y zeolite in the form of ion-exchanged in the ammonium or hydrogen form, and comprises a zeolite having a structural form of any one of the FAU, MOR, BEA structure form Characterized by a catalyst. The catalyst of claim 1, wherein the zeolite is mordenite having a silica / alumina molar ratio of 50 or more. The catalyst of claim 1, wherein the zeolite is mixed at 50 wt% to 80 wt% when the zeolite is combined with the inorganic binder. The catalyst of claim 1 wherein the Group VIII metal is a metal hydrate or oxide of any one of platinum, palladium, rhodium and ruthenium. The catalyst of claim 1 wherein the Group VIII metal is reduced ruthenium. The catalyst according to claim 1, wherein the second metal element is an oxide and a hydrate of tin. The catalyst of claim 1, wherein the amount of the Group VIII metal is loaded in an amount of 0.005 to 0.1 parts by weight based on 100 parts by weight of the mixed carrier of the zeolite and the inorganic binder. The catalyst of claim 1, wherein the amount of the second metal is supported by 0.05 to 1 parts by weight based on 100 parts by weight of the mixed carrier of the zeolite and the inorganic binder. The catalyst of claim 1, wherein the Group VIII metal and the second metal are supported on the mixed carrier of the zeolite and the inorganic binder by ion exchange, impregnation, or physical mixing. A method for gas phase isomerization of dimethylnaphthalene-rich fractions having a dimethylnaphthalene fraction of at least 50% by weight relative to the total weight of the reactants in the presence of a catalyst according to claim 1. The method of claim 11, wherein the isomerization reaction is characterized in that the mixture of dimethyl naphthalene, 2,6-dimethylnaphthalene-free dimethyl naphthalene mixture, trimethylnaphthalene, 1-methylnaphthalene, 2-methylnaphthalene, and naphthalene Way. 12. The dimethylnaphthalene-rich fraction of claim 11, wherein the dimethylnaphthalene-rich fraction has a dimethylnaphthalene fraction of at least 50% by weight relative to the total weight of the reactants, and less than 20% by weight of 2,6-dimethylnaphthalene relative to the total weight of dimethylnaphthalene in the reactants. A 2,6-dimethylnaphthalene lean fraction is used as a reactant. The dimethylnaphthalene-rich fraction of claim 13, wherein the dimethylnaphthalene-rich fraction has a dimethylnaphthalene fraction of 70% by weight or more relative to the total weight of the reactants, and less than 10% by weight of 2,6-dimethylnaphthalene, based on the total weight of dimethylnaphthalene in the reactants. , 6-Dimethylnaphthalene lean fraction is used as a reactant. The method of claim 11, wherein the gas phase isomerization reaction of dimethylnaphthalene is performed at a pressure range of 100 ^o C to 500 ^o C and 0 to 1000 psig. The method of claim 15, wherein the gas phase isomerization reaction of dimethylnaphthalene is carried out at a pressure range of 200 ^o C to 400 ^o C, 100 to 500 psig. According to claim 11, The gas phase isomerization reaction of dimethyl naphthalene is 0.1 ~ 20 h ^-1 , at a space velocity of, Wherein the molar ratio of hydrogen to reactant is from 1:20 to 20: 1. The method of claim 17, wherein the gas phase isomerization reaction of dimethylnaphthalene is 0.1 ~ 10 h ^-1 , at a space velocity of, Wherein the molar ratio of hydrogen to reactants is carried out at 1:10 to 10: 1.

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