KR101359973B1 - Transalkylation Catalyst for Producing Mixed Xylene from Aromatic Compounds - Google Patents

Abstract

The present invention relates to a transalkylation catalyst for producing mixed xylenes from aromatic compounds, and provides a transalkylation catalyst supported on platinum zeolite with support for platinum and cobalt, molybdenum or cobalt and molybdenum.
By using the catalyst according to the present invention, in the production of mixed xylene by transalkylation reaction from an aromatic mixture such as toluene, C9, C9 + and the like, it is possible to give the catalyst a hydrogenation function while keeping the acid point of the catalyst constant, It has sulfur resistance, high yield can be obtained from mixed xylene production by transalkylation reaction from aromatic compound, and long-term stability of the catalyst can be ensured.

Description

Transalkylation Catalyst for Producing Mixed Xylene from Aromatic Compounds}

The present invention relates to the development of transalkylation catalysts for producing mixed xylenes from toluene, C9 and C9 + aromatic compounds.

Isomers of xylene are para-xylene, ortho-xylene and meta-xylene, and these mixed xylene isomers are used as the main basic oils in the petrochemical industry. In particular, xylene is mostly used as a basic raw material of polyester and PET. Recently, as China's demand for xylene increased, the demand for xylene around the world increased, which led to an increase in the price of xylene.

Traditional xylene manufacturing processes can be prepared by transalkylation of benzene and / or toluene with aromatic compounds having 9 or more carbon atoms (hereinafter referred to as C9 + aromatic compounds) such as 1,2,4-trimethylbenzene. Other processes of xylene production include xylene production by xylene isomerization and a method of producing xylene and benzene by disproportionation of toluene.

As a catalyst used in the transalkylation reaction for producing mixed xylene, an acid point catalyst such as zeolite, a metal catalyst or a noble metal catalyst may be mentioned. Among these, acid spot catalysts include mordenite, beta, USY, ZSM-5, and metal catalysts, such as nickel, magnesium, manganese, cobalt, chromium, zinc, gallium, tungsten, tin, molybdenum, lead, iron, and the like. One or more mixed catalysts of the Group VIII metals may be used. As the noble metal catalyst, one or more precious metals selected from the group of Ru, Rh, Pt, Pd, Au, Ag, Ir can be used, and further, a metal catalyst and a noble metal catalyst can be used simultaneously.

U.S. Patent No. 4,083,886 relates to the development of a catalyst for transalkylation of toluene and aromatic compounds and describes a process for preparing a catalyst in which mordenite treated with ammonia water is formed into an inorganic oxide binder. However, when the transalkylation reaction is performed using such a catalyst, when an aromatic compound of C9 + or more is present in the reactant, coke may be generated on the surface of the mordenite to rapidly deactivate the activity of the catalyst. In addition, when sulfur reactants are included in the reactants, the active point of the catalyst is inactivated to lower the activity of the catalyst or the stability of the catalyst is poor.

Further, US Pat. Nos. 6,613,709 and 6,864,400 optionally include one or more metals selected from zeolites and VIIBs, VIBs and iridium, together with one or more metals selected from Groups III and IV, preferably indium and tin of the Periodic Table. Disclosed is a transalkylation catalyst comprising a.

Generally, when mixed xylene is prepared by a transalkylation reaction using toluene and C9 and C9 + aromatic compounds as a reactant, the polymerization reaction proceeds at the surface acid point of the catalyst by the aromatic compound of C9 + to form oligomers or cokes. This leads to a sudden deactivation of the catalyst.

Accordingly, the present invention improves the yield of mixed xylene and improves the stability of the transalkylation reaction by improving the catalyst used in preparing mixed xylene by transalkylation reaction using toluene and C9 and C9 + aromatic compounds as reactants. I would like to.

Furthermore, even when sulfur is included in the reactants, it is desirable to provide a catalyst capable of stably transalkylating by improving the reaction stability of the catalyst against sulfur.

The present invention relates to a transalkylation catalyst used to generate mixed xylenes from aromatic compounds. According to a first embodiment, a transalkylation catalyst comprising platinum and cobalt, molybdenum or cobalt and molybdenum supported on a zeolite carrier is provided. Is provided.

According to a second embodiment of the present invention, the zeolite carrier may be a mordenite zeolite, beta zeolite or a mixture thereof.

According to a third embodiment of the present invention, the zeolite carrier may have a molar ratio of silica to alumina of 10 to 250: 1.

According to the fourth embodiment of the present invention, the platinum may be supported by 0.01 to 1.0% by weight based on the weight of the zeolite carrier, and the cobalt, molybdenum or a mixture thereof may be supported by 0.1 to 5.0% by weight.

In producing mixed xylenes by transalkylation reactions from aromatic mixtures such as toluene, C9, C9 + and the like, by using the catalyst according to the present invention, it is possible to give the catalyst a hydrogenation function while keeping the acid point of the catalyst constant.

As a result, a high yield of mixed xylene production by transalkylation reaction from an aromatic compound to the reactant can be obtained, and long-term stability of the catalyst can be ensured.

Furthermore, even if sulfur-containing impurities are present in the reactants, mixed xylene production can be stably performed by a transalkylation reaction, thereby obtaining a constant yield.

1 is a graph showing the production yield of mixed xylenes according to reaction time in producing mixed xylenes in Comparative Examples 1, 2 and 3. FIG.
2 is a graph showing the yield of mixed xylene according to the reaction time in producing mixed xylene in Example 1 and Example 4.

The present invention relates to a catalyst capable of stably preparing mixed xylenes through transalkylation reactions from toluene and C9 + aromatic compounds such as 1,2,4-TMB (C9) and naphthalene (C10).

In the present invention, as the catalyst, the stability of the catalyst can be improved by supporting a noble metal and a metal on the zeolite carrier.

Toluene may be reacted with C9 + aromatic compounds such as C9 aromatic compounds such as 1,2,4-trimethylbenzene and C10 or more aromatic compounds such as naphthalene to prepare mixed xylenes through transalkylation reactions. However, in the actual reaction, the disproportionation of toluene from the reactants and the transalkylation reaction between the toluene and the C9 reactant occur simultaneously in the prepared catalyst. However, precisely how much disproportionation and transalkylation reactions occur from the reactants is not the main concern of the present invention, and therefore is not specifically mentioned here, and only transalkylation reactions are intended to be mentioned as representative reactions.

In the catalyst used for the transalkylation reaction of toluene and C9 aromatic compound, zeolite can be used as a carrier. As such a zeolite carrier, mordenite zeolite and beta (beta, β) zeolite can be used. They have a pore structure of about 6.5 kV x 7.0 kV and have large pores. Thus, the reaction mixtures can sufficiently pass through the pores so that the interior of the pores can suitably provide a reaction site. However, the ZSM-5 type zeolite carrier has a small pore structure, and since the reactant cannot enter the reaction, most of the reactions are reported on the surface thereof, which is not suitable as a catalyst carrier.

It is preferable that the silica and alumina of the zeolite carrier have a molar ratio of 10 to 250: 1. If the silica / alumina molar ratio outside the above range is less than 10: 1 because the acid point of the catalyst is too strong, the reaction activity is too strong to increase the side reaction product, there is a problem that the deactivation of the catalyst suddenly occurs. In addition, when the silica / alumina mole ratio exceeds 250: 1, the reaction activity of the catalyst is weak, which may cause a problem of decreasing the yield of mixed xylene.

Among the zeolite carriers, the mordenite zeolite may use a zeolite in the form of sodium, ammonium nitrate, or hydrogen (H type). These zeolites have different acid points depending on whether they are in the form of sodium, ammonium nitrate or hydrogen, which are important factors affecting the activity of the catalyst. Therefore, in some cases, it is more preferable to use the one converted to mordenite in the hydrogen form by performing ion exchange and calcination to give a catalyst acid point to the mordenite zeolite.

On the other hand, C9 + aromatic compounds, such as bicyclic aromatic compounds such as naphthalene, present in the reactants for producing mixed xylene, when the transalkylation reaction proceeds in the presence of a catalyst, the coupling reaction proceeds at the internal or external acid point of the catalyst, Oligomerization can occur, in which case pores of the catalyst or blocking acid sites of the catalyst promote catalyst deactivation.

Therefore, in order to solve this problem, it is necessary to induce a hydrogenation reaction so that the reactants do not proceed at the acid point of the surface or the inside of the catalyst. For this purpose, it is very important to effectively select and support the catalysts to impart hydrogenation function on the surface of the catalyst.

In addition, when sulfur-containing components are included in the reaction raw materials, the deactivation of the supported catalysts is impaired, thereby deteriorating the hydrogenation function and inducing the catalyst.

To this end, in the present invention, a noble metal such as Pt, Pd, Au, Ru, etc. may be used as the hydrogenation catalyst on the carrier, and Pt is most suitable for imparting a hydrogenation function.

Such platinum catalyst is preferably supported by 0.01 to 1.0% by weight relative to the weight of the zeolite carrier. When included in less than 0.1% by weight it is not possible to give sufficient hydrogenation function, the reactants at the acidic point of the surface or the inside of the catalyst can not inhibit the deactivation of the catalyst due to the polymerization reaction, if more than 1.0% by weight additional effects An increase in is not obtained, and a stronger loss of hydrogenation results in ring loss of aromatic compounds. In addition, the use of expensive precious metal catalysts only increases, resulting in increased costs.

On the other hand, when using the Pt as a catalyst, Pt has a strong hydrogenation function, such a strong hydrogenation function may break the ring of the aromatic reactants as a reactant may reduce the yield of the product. In order to solve this problem, a catalyst capable of controlling the hydrogenation function of Pt is required, and for this purpose, it is preferable to introduce a second metal into the zeolite carrier together with platinum. Cobalt and molybdenum are mentioned as said 2nd metal.

The second metal is preferably supported by 0.1 to 5% by weight based on the weight of the zeolite carrier. When the amount of the second metal used is less than 1.0% by weight, the hydrogenation function of the catalyst cannot be sufficiently controlled. When the amount of the second metal is more than 5% by weight, the hydrogenation function of platinum is lost and the catalyst is inactivated. .

Meanwhile, nickel phosphite, tungsten carbide, molybdenum sulfide, or a mixture thereof may be further supported on the catalyst in which platinum and cobalt or molybdenum are supported. These nickel phosphites, tungsten carbide, and molybdenum sulfide have hydrogenation and desulfurization functions simultaneously, and further support hydrogenation and desulfurization functions by supporting nickel phosphite on a catalyst supported with platinum and cobalt or molybdenum. It can be strengthened so that the sulfur resistance can be further improved when the reactants for the transalkylation reaction contain sulfur.

In this case, the nickel phosphite, tungsten carbide, molybdenum sulfide or a mixture thereof is preferably supported in an amount such that the total amount of the components supported on the zeolite carrier is 7.0% by weight or less based on the weight of the carrier. If the content of the total catalyst component exceeds 7.0% by weight based on the weight of the carrier, nickel posterite, tungsten carbide or molybdenum sulfide may inhibit the catalytic activity by blocking the pore or acid point of the zeolite.

As described above, in the preparation of mixed xylene by supporting platinum and cobalt on a mordenite zeolite carrier, the hydrogenation function can be imparted while maintaining the acid point of the mordenite catalyst, and thus the transalkylation reaction can be stably achieved. Thereby, the manufacturing yield of mixed xylene can be improved. Furthermore, even if it contains sulfur impurity in a reactant, sulfur resistance can be aimed at and it can manufacture the mixed xylene by transalkylation reaction stably.

Example

Hereinafter, the present invention will be described more specifically with reference to examples. The following examples are illustrative only and are not intended to limit the broad form of the present invention.

All percentages of liquids and solids are by weight, except where noted in the examples below or otherwise obvious in the context.

Example  One

H type mordenite zeolite carrier (MOR) having a molar ratio of silica / alumina of 20 was impregnated in an aqueous solution of Co (NO ₃ ) ₂ .6H ₂ O to support 0.5 wt% of cobalt based on the weight of the carrier on the carrier. It was.

The cobalt-supported H type mordenite zeolite carrier was heat-treated at 500 ° C. for 2 hours.

The cobalt-supported H type mordenite carrier was impregnated in an aqueous solution of H ₂ PtCl ₆ to support 0.05 wt% platinum based on the weight of the carrier in the catalyst of cobalt / mordenite.

The Pt-supported cobalt / mordenite was heat-treated at 500 ° C. for 2 hours to obtain a final catalyst on which the cobalt and platinum were supported on the H type mordenite zeolite carrier.

The transalkylation reaction was carried out using the catalyst obtained in the following manner and the performance of the catalyst was tested.

1.0 g (20-30 mesh) of the obtained catalyst was charged in a fixed bed reactor, and the catalyst was reduced to hydrogen at 400 ° C. for 2 hours after maintaining the reactor pressure at 30 bar.

Subsequently, an aromatic compound containing toluene and 1,2,4-trimethylbenzene (1,2,4-TMB) in a molar ratio of 50:50 was used as a transalkylation reaction raw material, and a high pressure pump was added to the reactor. Thereafter, the reaction was carried out under reaction conditions as described in Table 1.

The product obtained by the above reaction and its content are shown in Table 1 below.

Example  2

The transalkylation reaction was carried out in the same manner and in the same manner as in Example 1, except that an aromatic compound containing toluene, 1,2,4-trimethylbenzene and naphthalene at 27: 70: 3 was used as a raw material for transalkylation reaction. The catalyst performance was tested.

The product obtained by the above reaction and its content are shown in Table 1 below.

Example  3

A H type mordenite zeolite carrier having a molar ratio of silica / alumina of 20 was impregnated in an aqueous solution of H ₃ Mo ₁₂ O ₄₀ P · xH ₂ O to support 0.5 wt% molybdenum based on the weight of the carrier on the carrier. Except for one, the final catalyst on which molybdenum and platinum were supported was obtained in the same manner as in Example 1.

The obtained catalyst was subjected to a transalkylation reaction in the same manner and conditions as in Example 2, and the catalyst performance was tested.

The product obtained by the above reaction and its content (% by weight) are shown in Table 1 below.

Example 1 Example 2 Example 3 Reaction condition Temperature: 400 ° C., Pressure: 30 kg / cm ² , WHSV = 2.4hr ^-1 , H ₂ / HC = 3 Reactant, molar ratio (%) Toluene: 1,2,4-TMB = 50: 50 Toluene: 1,2,4-TMB: naphthalene = 27: 70: 3 catalyst Pt-Co / MOR Pt-Co / MOR Pt-Mo / MOR product benzene 2.9 2.7 2.9 toluene 20.5 15.9 16.9 Ortho xylene 8.6 8.5 8.8 Metaxylene 19.0 19.3 19.8 Para-xylene 9.8 8.6 8.8 C9 ~ C10 39.2 45 42.8 Mixed Xylene 37.4 36.4 37.4

Comparative Example  One

A hydrogen mordenite zeolite carrier having a molar ratio of silica / alumina of 20 was used as a catalyst, and no precious metal or metal was supported on the carrier.

Using the catalyst, the transalkylation reaction was carried out in the same manner and conditions as in Example 1, and the catalyst performance was tested.

The products obtained by the above reaction and their contents are shown in Table 2 below.

Comparative Example  2

A hydrogen mordenite zeolite carrier having a molar ratio of silica / alumina of 20 was used as a catalyst, and no precious metal or metal was supported on the carrier.

Using the catalyst, the transalkylation reaction was carried out in the same manner and conditions as in Example 2, and the catalyst performance was tested.

The products obtained by the above reaction and their contents are shown in Table 2 below.

Comparative Example  3

In the same manner as in Example 1, except that 0.5% by weight of Fe was supported based on the weight of the carrier by using Fe (NO ₃ ) ₃ .9H ₂ O aqueous solution instead of Co (NO ₃ ) ₂ .6H ₂ O aqueous solution. A final catalyst bearing iron and platinum was obtained.

The transalkylation reaction was carried out in the same manner and in the same manner as in Example 1 using the catalyst obtained above, and the catalyst performance was tested.

The products obtained by the above reaction and their contents are shown in Table 2 below.

Comparative Example  4

In the same manner as in Example 1, except that 0.5% by weight of Mg was supported based on the weight of the carrier using Mg (NO ₃ ) ₂ .6H ₂ O aqueous solution instead of Co (NO ₃ ) ₂ .6H ₂ O aqueous solution. A final catalyst bearing magnesium and platinum was obtained.

The transalkylation reaction was carried out in the same manner and in the same manner as in Example 1 using the catalyst obtained above, and the catalyst performance was tested.

The products obtained by the above reaction and their contents are shown in Table 2 below.

Comparative Example  5

Instead of H ₂ PtCl ₆ aqueous solution of Pd (NH _{3) 4} · Cl, and cobalt, and palladium in the same manner as in Example 1, except _2, using H ₂ O solution to the supported palladium of 0.05% by weight based on the carrier weight This supported final catalyst was obtained.

The transalkylation reaction was carried out in the same manner and in the same manner as in Example 1 using the catalyst obtained above, and the catalyst performance was tested.

The product obtained by the above reaction and its content (% by weight) are shown in Table 2 below.

Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Reaction condition Temperature: 400 ° C., Pressure: 30 kg / cm ² , WHSV = 2.4hr ^-1 , H ₂ / HC = 3 Reactant
(weight%) Toluene: 1,2,4-TMB = 50: 50 Toluene: 1,2,4-TMB: naphthalene = 27: 70: 3 Toluene: 1,2,4-TMB = 50: 50 catalyst H-MOR H-MOR Pt-Fe / MOR Pt-Mg / MOR Pd-Co / MOR product 2.7 2.4 benzene 2.0 2.8 2.5 19.1 49.7 toluene 13.6 17.4 16.4 7.5 2.7 Ortho xylene 6.2 6.0 6.9 16.6 5.0 Metaxylene 13.9 14.1 15.4 8.2 3.2 Para-xylene 6.6 6.6 7.4 45.9 37 C9 ~ C10 57.7 53.1 51.4 32.3 10.9 Mixed xylene 26.7 26.7 29.7

The results of Example 1 and Comparative Example 1, in which mixed xylene was prepared by the same method, except that different catalysts were used, were compared with those of Comparative Example 1 using a hydrogen type mordenite zeolite catalyst. It can be seen that the mixed xylene product content in Example 1 using a catalyst in which platinum and cobalt are supported on a hydrogen-type modest anitolite zeolite catalyst as the catalyst of the present invention is high.

In particular, when comparing Examples 2 and 3 and Comparative Example 2, it can be seen that the product content of the mixed xylene is significantly increased when naphthalene is included in the reactants.

In addition, when a metal other than the cobalt or molybdenum provided in the present invention is supported on the hydrogen-type mordenite zeolite catalyst, it shows that the mixed xylene product content is lower than that of Comparative Example 1. Can be.

As described above, when the transalkylation reaction for producing mixed xylene is performed using the catalyst according to the present invention, it can be seen that the yield of mixed xylene can be significantly increased.

In addition, as shown in Figure 1, when comparing the change of the mixed xylene with the reaction time, it can be seen that the degree of deactivation of the catalyst of Comparative Example 1 is greatly improved. In other words, it can be seen that the rate of yield reduction of mixed xylene is significantly reduced.

Example  4

In the same manner as in Example 1, a cobalt and platinum-supported catalyst was prepared on an H type mordenite zeolite carrier.

The transalkylation reaction was carried out under the same reaction conditions as in Example 1, except that a reaction material containing a sulfur compound of dibenzothiobene at a concentration of 11,513 ppm (sulfur basis: 2,000 ppm) was used.

The products obtained by the above reaction and their contents are shown in Table 3 below. Furthermore, the mixed xylene yield change with the reaction time is shown in a graph in FIG.

Example 4 Reaction condition Temperature: 400 ° C., Pressure: 30 kg / cm ² , WHSV = 3hr ^-1 , H ₂ / HC = 3 Reactant, wt% Toluene: 1,2,4-TMB = 50: 50 product(%) benzene 4.8 toluene 22.5 ortho-xylene 8.8 meta-xylene 19.9 para-xylene 9.2 C ₉ to C ₁₀ 34.8 Mixed xylene 37.9

Comparing the results of Table 3 with the results of Example 1, it can be seen that despite the presence of a sulfur compound, mixed xylene is produced in a high yield equivalent to that of Example 1.

In addition, as shown in Figure 2, when comparing the change of the mixed xylene according to the reaction time, H-type mordenite catalyst supported with platinum and cobalt or nickel phosphide mixed according to the reaction time in the presence of sulfur compounds It can be seen that the yield of xylene remains constant.

Claims (4)

As a transalkylation catalyst used to produce mixed xylenes from aromatic compounds,
Platinum and cobalt on zeolite carriers; Platinum and molybdenum; Or platinum, cobalt and molybdenum are supported,
In addition, nickel phosphite, tungsten carbide, molybdenum sulfide or mixtures thereof are supported.
Wherein said mixed xylene is a mixture of para-xylene, ortho-xylene and meta-xylene.

The transalkylation catalyst of claim 1, wherein the zeolite carrier is mordenite zeolite, beta zeolite, or a mixture thereof.
The transalkylation catalyst of claim 1, wherein the zeolite carrier has a molar ratio of silica to alumina of 10 to 250: 1.
The transalkylation catalyst according to claim 1, wherein the platinum is supported by 0.01 to 1.0% by weight based on the weight of the zeolite carrier, and the cobalt, molybdenum or cobalt and molybdenum is supported by 0.1 to 5.0% by weight.

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