JP2001059090A - Conversion of aromatic hydrocarbon - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accomplish effective conversion of aromatic hydrocarbons with suppressed consumption of hydrogen and minimized deterioration of the catalyst activity by decreasing the content of nonaromatic compounds in the feedstock of the aromatic hydrocarbon, when aromatic hydrocarbon is converted. SOLUTION: The conversion of aromatic hydrocarbons (preferably transalkylation reaction) is carried out by allowing (A) aromatic hydrocarbon including benzene and <=1 wt.% of nonaromatic compounds to come into contact with (B) a catalyst, preferably a zeolite and the like-including catalyst. The component A is prepared by reducing the content of nonaromatic compounds from the crude aromatic hydrocarbon raw material including benzene and nonaromatic compounds to <=1%. In a preferred embodiment, the raw material is an aromatic hydrocarbon including alkyl aromatic hydrocarbon of 9 or more carbon atoms. This reaction system preferably includes hydrogen whereby the heat generated by the decomposition of nonaromatic compound can be controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for converting aromatic hydrocarbons, and more particularly to a method for converting aromatic hydrocarbons using an aromatic hydrocarbon raw material containing benzene and containing 1% by weight or less of non-aromatic compounds. The present invention relates to a method for converting a group III compound.

[0002]

2. Description of the Related Art Recently, requirements and regulations for environmental problems have become strict. Above all, the demand for cleaner fuels is increasing. In particular, regarding gasoline, the effect of benzene in gasoline on human health is becoming a major problem, and the benzene concentration in gasoline is already regulated in the United States. There are also regulatory moves in Japan and Europe, and oil companies are responding to the reduction of benzene in gasoline.

In order to meet the demand for high octane fuel in the market,
Alkyl aromatic hydrocarbons such as toluene and xylene having a high octane number, such as benzene, have been contained in gasoline at high concentrations as gasoline base materials which have been more important than before. Gasoline is usually produced in refinery processes such as catalytic reforming and cracking, and the distillate in each process contains benzene. The effective use of benzene is an urgent issue, as the amount of benzene alone in the reformed gasoline produced in Japan will be about 700,000 tons. As a method of using benzene, a technique for producing toluene and xylene by a transalkylation reaction with an aromatic hydrocarbon having 9 or more carbon atoms is known. Toluene and xylene are considered to have no problem on human health like benzene at present, and since they have a higher octane number than benzene, they are preferable reactions from the viewpoint of increasing the octane number of gasoline.

Usually, benzene extracted from gasoline is separated by a distillation step. This benzene fraction contains a large amount of non-aromatic compounds near the benzene boiling range, especially non-aromatic hydrocarbons such as paraffin, olefin, and naphthene. When a benzene fraction containing a large amount of these non-aromatics is transalkylated with an aromatic hydrocarbon having 9 or more carbon atoms in the presence of hydrogen, a decomposition reaction of paraffin and the like occurs along with the transalkylation of the aromatic. When a decomposition reaction, which is a side reaction, occurs, there is a problem in that hydrogen consumption increases and heat generation due to heat of decomposition increases.

US Pat. No. 5,347,061 discloses a process for converting benzene and hydrocarbons having 9 or more carbon atoms in a gasoline fraction into C7 and C8 alkylaromatic compounds. This is a method in which a benzene-rich hydrocarbon stream having 6 carbon atoms and a hydrocarbon stream having 9 or more carbon atoms obtained by distilling reformed gasoline in the presence of an acidic metallosilicate catalyst are subjected to a cracking reaction and a transalkylation reaction. And a process for producing an aromatic hydrocarbon having 7 and 8 carbon atoms by an alkylation reaction.
However, in U.S. Pat. No. 5,347,061,
In order to alkylate benzene, hydrocarbons having 9 or more carbon atoms are actively catalytically cracked and used as an alkylating agent. Therefore, the presence of a non-aromatic hydrocarbon is essential.

Japanese Patent Application Laid-Open No. 9-38497 discloses a benzene-containing fraction separated from a naphtha catalytic reforming product in the presence of a crystalline aluminosilicate catalyst supporting a Group VIII metal component of the Periodic Table of the Elements. Aromatic hydrocarbon conversion method for producing a reaction product mainly composed of monoalkylbenzene and dialkylbenzene by a transalkylation reaction using a fraction and a trialkylbenzene-containing fraction fractionated from a catalytic cracking product as raw materials Is disclosed. As a crystalline aluminosilicate, mordenite having a low shape selectivity index has a large deterioration due to coking and is of low practical value.
Is preferred.

Japanese Patent Application Laid-Open No. 9-155198 discloses that the maximum pore size of micropores is 0.6 to 1.0 nm, and that SiO ₂ /
A carrier containing a zeolite having an Al ₂ O ₃ ratio of 50 or more,
Using a catalyst supporting a metal selected from Group VIII metals and Group VIA metals or a compound thereof,
A method for converting an aromatic flag hydrocarbon compound having 9 or more carbon atoms contained in a feedstock having a specific boiling point and not containing benzene into toluene and an aromatic hydrocarbon compound having 8 carbon atoms in the presence of hydrogen. Is disclosed. Mordenite is preferred as the zeolite, nickel as the metal,
Palladium and molybdenum are said to be preferred.

Japanese Patent Application Laid-Open No. Hei 9-38505 discloses that the maximum pore diameter of micropores is 0.6 to 1.0 nm, and that SiO ₂ / A
Using a catalyst in which a metal or a compound thereof selected from Group VIII metals and Group VIA metals is supported on a carrier containing a zeolite having an l ₂ O ₃ ratio of 50 or more, a feed oil having a specific boiling point range is used. There is disclosed a method of converting benzene and an aromatic hydrocarbon compound having 9 or more carbon atoms into toluene and an aromatic hydrocarbon compound having 8 carbon atoms in the presence of hydrogen.

Japanese Patent Application Laid-Open No. 9-187658 discloses that the maximum pore diameter of micropores is 0.6 to 1.0 nm, and that SiO ₂ /
A support containing a zeolite having an Al ₂ O ₃ ratio of less than 50,
Using a catalyst supporting a metal selected from Group VIII metals and Group VIA metals or a compound thereof,
A method is disclosed in which benzene and an aromatic hydrocarbon compound having 9 or more carbon atoms in a feed oil having a specific boiling point range are converted into toluene and an aromatic hydrocarbon compound having 8 carbon atoms in the presence of hydrogen.

[0010] WO 98/12159 discloses that palladium-supported dealuminated silica / alumina is prepared by using an aromatic raw material containing at least 20% or more of an aromatic compound having 9 carbon atoms having an ethyl group or a propyl group. Ratio 12-3
A process is disclosed for contacting a catalyst containing mordenite of 0 in the presence of hydrogen to convert an aromatic feedstock to obtain a toluene, xylene rich product.

WO 96/24568 discloses a catalyst containing a zeolite having a control index of 0.5 to 3 and having a hydrogenation site and treated to suppress nuclear hydrogenation ability, and an aromatic compound having 9 or more carbon atoms. A process is disclosed in which a hydrocarbon is contacted with a feed containing benzene and / or toluene to convert it to an aromatic having less than 9 carbon atoms.

US Pat. No. 5,406,016 describes a process for converting a benzene and an alkyl aromatic having 10 or more alkyl groups having 10 or more carbon atoms into methylbenzenes using a 12-membered zeolite under specific reaction conditions. It has been disclosed.

However, in the above example, the efficiency of the conversion of the aromatic compound is not sufficient, and there is no description about the treatment method of the non-aromatic compound.

[0014]

SUMMARY OF THE INVENTION An object of the present invention is to reduce the amount of hydrogen consumption, reduce catalyst deterioration, and convert benzene to a more effective benzene when converting an aromatic hydrocarbon feedstock containing benzene. To provide a method for converting an aromatic hydrocarbon feedstock containing

[0015]

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve the above-mentioned problems, and as a result, have found that non-aromatic compounds in aromatic hydrocarbon feedstock, especially paraffin, olefin, naphthene and the like. It has been found that by reducing the non-aromatic hydrocarbon content, when converting aromatic hydrocarbons, the hydrogen consumption is suppressed and catalyst deterioration is small. Thereby, generation of heat of decomposition of the non-aromatic compound in the reaction can be suppressed.

The present invention provides a method for converting aromatic hydrocarbons using a benzene-containing aromatic hydrocarbon raw material having a non-aromatic compound content of 1% or less.

That is, the present invention is a method for converting aromatic hydrocarbons, which comprises contacting a catalyst with an aromatic hydrocarbon containing benzene and containing 1% by weight or less of a non-aromatic compound.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail.

In the present invention, aromatic hydrocarbons are converted by using a benzene-containing aromatic hydrocarbon raw material containing 1% by weight or less of non-aromatic compounds. The raw material is preferably used after removing non-aromatic compounds to 1 wt% or less from a crude aromatic hydrocarbon raw material containing benzene and non-aromatic compounds. The aromatic hydrocarbon obtained by the conversion may be used as a general chemical raw material, or may be used as a gasoline base material that is insufficient for extracting benzene, and benzene extracted from gasoline can be effectively used.

In the present invention, the non-aromatic compound is a compound other than an aromatic hydrocarbon, and specifically, a non-aromatic hydrocarbon such as paraffin, olefin, naphthene and the like. The present invention is characterized in that these non-aromatic compounds are 1% by weight or less of the aromatic hydrocarbon containing benzene as a raw material.

In the present invention, the conversion of an aromatic hydrocarbon specifically includes transalkylation, dealkylation,
It refers to at least one of each reaction of disproportionation. The reaction is
The reaction is performed under conditions in which at least one of the transalkylation, dealkylation, and disproportionation reactions occurs, and is usually performed in the presence of hydrogen. The reaction pressure is 0.1 to 100 MPa,
Preferably, it is 0.5 to 60 MPa, more preferably 1
５０50 MPa. If the pressure is too low, the catalyst deteriorates quickly and the reaction rate becomes slow. If the pressure is too high, the apparatus is uneconomical. The reaction temperature is from 200 to 650 ° C, preferably from 250 to 500 ° C. If the reaction temperature is low, the reaction rate will be low, and if it is too high, the decomposition will be severe and the catalyst will be deteriorated quickly. The hydrogen flow rate is hydrogen / raw material (mol / mo
l), from 0.1 to 20 and preferably from 0.5 to 1
0 or less. If the flow rate is too low, the catalyst deteriorates quickly, and if the flow rate is high, it is uneconomical.

The raw material used in the present invention is an aromatic hydrocarbon containing benzene. As aromatic hydrocarbons, benzene, toluene, xylene, ethylbenzene,
It may contain any of trimethylbenzene, ethyltoluene, propylbenzene, tetramethylbenzene, ethylxylene, diethylxylene, propyltoluene, and other aromatic hydrocarbons. When toluene and / or xylene is taken out as a product, the content of toluene and / or xylene in the raw material needs to be equal to or less than the equilibrium composition.

As the raw material, a gas having a boiling range of gasoline usually obtained from each essential oil step, such as a catalytic reforming oil, can be used. Further, the raw material oil obtained from each essential oil step may be combined as a raw material. The feedstock oil, especially the feedstock from the reforming reactor, is usually separated by distillation into a fraction having an appropriate boiling point range such as a C5-fraction, a C6 fraction, a C7 fraction, a C8 fraction, and a C9 + fraction. Is done. In this reaction, the separated fractions may be used in combination, or may be used without separation. In any case, it is essential that the raw material contains benzene.

In the reforming reaction, generally, the fraction having a smaller number of carbon atoms has a higher non-aromatic compound content, and the C6 fraction may have a non-aromatic compound content exceeding 50%. These non-aromatic compounds are preferably separated from the aromatic compounds by distillation and extraction. After removing the non-aromatic compounds in this manner, the raw material is converted by contact with a catalyst.

The benzene-containing aromatic compound raw material used in the present invention is characterized by having a non-aromatic compound content of 1% or less. When the content of the non-aromatic compound exceeds 1 wt%, hydrogen consumption due to decomposition is severe, heat of decomposition is increased, and degradation of the catalyst by decomposition products is large. The non-aromatic compound content is preferably 0.5 wt%
Or less, more preferably 0.1 wt% or less.

The non-aromatic compound is preferably removed from the raw material by distillation or extraction. The removal of the non-aromatic compounds may be performed after the feed oil is separated into each fraction by distillation or before the distillation, as long as it is before the conversion reaction. The removed non-aromatic compound can be used as a gasoline base material directly or by increasing the octane value by an isomerization step.

There is no particular limitation on the benzene content in the feedstock, but in order to efficiently convert benzene to other aromatic hydrocarbons, 5 wt% or more and 80 wt% or less, preferably 10 wt% or less.
wt% or more and 70 wt% or less, more preferably 15 wt%
Not less than 60 wt%.

Further, in the present invention, it is preferable that the feedstock oil contains an alkyl aromatic hydrocarbon having 9 or more carbon atoms. Among them, it is preferable to contain an alkyl aromatic hydrocarbon having 9 and 10 carbon atoms. Alkyl aromatic hydrocarbons having 9 carbon atoms are trimethylbenzene, ethyltoluene and propylbenzene, and alkylaromatic hydrocarbons having 10 carbon atoms are tetramethylbenzene, ethylxylene, diethylxylene, propyltoluene and butylbenzene. It is. Among them, trimethylbenzene and tetramethylbenzene are preferred. The content of the alkyl aromatic hydrocarbon having 9 or more carbon atoms in the feedstock is not particularly limited, but is preferably 5 wt% in order to efficiently promote the transalkylation with benzene.
The content is preferably 90% by weight or less. More preferably 7
It is at least 85 wt%. More preferably, 10
It is not less than wt% and not more than 80 wt%.

In the present invention, more specifically, a transalkylation reaction is carried out using an aromatic hydrocarbon raw material in which benzene and a non-aromatic compound containing an aromatic hydrocarbon having 9 or more carbon atoms are 1% or less. It is characterized by obtaining things.
A transalkylation reaction with the product may occur. As the transalkylation reaction, specifically, the production of toluene and xylene from benzene and trimethylbenzene, the production of toluene, xylene and trimethylbenzene from benzene and tetramethylbenzene, the production of toluene from benzene and xylene, and the production of toluene and trimethylbenzene Examples include the production of xylene, the production of xylene and trimethylbenzene from toluene and tetramethylbenzene, and the production of ethylbenzene from benzene and diethylbenzene, but any other transalkylation reaction may occur. By these reactions, both benzene and aromatic hydrocarbons having 9 or more carbon atoms in the feed oil decrease, and aromatic hydrocarbons having 7 and 8 carbon atoms in the product increase. The product has 7 carbon atoms and / or 8 carbon atoms.
Preferably, the aromatic hydrocarbon is extracted by distillation or the like. The remaining product may be recycled.

In the present invention, in addition to the transalkylation reaction, a disproportionation reaction, a dealkylation or an alkylation reaction may occur.

In a preferred embodiment of the present invention, a benzene distillate obtained by distilling gasoline and an aromatic hydrocarbon feedstock containing an aromatic hydrocarbon having 9 or more carbon atoms are mixed, and the non-oil in the mixture is mixed. After reducing the aromatic compound content to 1% by weight or less, the aromatic hydrocarbon is converted by contacting with a catalyst, and the resulting aromatic hydrocarbons having 7 and 8 carbon atoms are taken out. For producing aromatic hydrocarbons, or non-aromatic compounds in a benzene distillate obtained by distilling gasoline and / or an aromatic hydrocarbon feedstock containing aromatic hydrocarbons having 9 or more carbon atoms Are reduced, and the mixture is contacted with a catalyst having a non-aromatic compound content of 1% by weight or less in the mixture to convert aromatic hydrocarbons, thereby producing aromatics having 7 and 8 carbon atoms. Charring Remove the oxygen, carbon atoms 7 and 8
Is a method for producing an aromatic hydrocarbon.

The catalyst used in the present invention is an aromatic conversion catalyst, and specifically, any catalyst can be used as long as transalkylation occurs. Also, disproportionation, dealkylation or alkylation may occur. Preferably,
While retaining the methyl group, it selectively dealkylates the ethyl group and the propyl group, and at the same time has transalkylation ability. Specifically, a shape-selective metallosilicate catalyst is preferable, and among them, a crystalline aluminosilicate is preferable. Particularly, zeolite is preferable, and any zeolite such as mordenite, Y, X, beta, and ZSM-5 can be used, but mordenite is more preferable.

The zeolite may be ion-exchanged for a suitable metal ion or hydrogen ion. Preferably it is of the hydrogen type.

[0034] A binder may be used as necessary for the catalyst. The binder is not particularly limited, alumina, silica alumina, titania, inorganic oxides such as magnesia, montmorillonite, kaolin, sepiolite, any such clays such as acid clay, can be used as they are, or in combination, Preferably, it is alumina. The amount of the binder is not particularly limited, but is preferably 20 wt% or more and 60 w
t% or less.

The catalyst preferably has a site having hydrogenation activity for the purpose of improving the activity of the catalyst and extending the life of the catalyst. Any material having hydrogenation activity can be used. Although the zeolite itself of the catalyst may have hydrogenation activity, it is preferably a group VIB of the periodic table,
It contains at least one of Group VIIB and Group VIII metals. Group VIB is specifically chromium, molybdenum, tungsten, preferably molybdenum. No.
Group VIIB is specifically manganese, technetium, rhenium, and preferably rhenium. Group VIII is iron, ruthenium, osmium, cobalt, rhodium,
Iridium, nickel, palladium and platinum are preferable, and nickel, palladium and platinum are preferable. Most preferred is rhenium. These metals are preferably supported alone or as a compound. The method for supporting the metal is not particularly limited, and a commonly used method such as an impregnation method and a CVD method can be used. The amount of metal carried is not particularly limited, and may be appropriately selected depending on the reaction conditions and the like.
t% to 10 wt%, more preferably 0.01 wt% to 5 wt%, even more preferably 0.02 wt% to 2 wt%
%.

[0036]

The present invention will now be described more specifically with reference to examples.

Example 1 105 g of powdery sodium-type synthetic mordenite, 45 g of α-alumina, 12 g of alumina sol (containing 10% by weight as alumina), 10.5 g of alumina gel (containing 70% by weight as alumina), and an appropriate amount of ion-exchanged water The mixture is kneaded for about 2 hours, the outer diameter 1.2mmφ × length 1.0mm
And dried at 120 ° C. for 16 hours. 50 g of this compact (at 520 ° C. dried) is fired and cooled at 400 ° C. for 5 hours in an air atmosphere. This is 80-85 using 100 g of a 10% by weight aqueous solution of ammonia chloride.
The mixture was treated at 1 ° C. for 1 hour, filtered, and washed with water. Further, the mixture is treated with 100 g of a 5% by weight aqueous solution of tartaric acid at 80 to 85 ° C. for 3 hours. It is immersed in 6.5 g of a 5% by weight aqueous rhenium (VII) solution at room temperature. This one
After drying at 20 ° C for 16 hours, the mixture is calcined at 540 ° C for 8 hours in an air atmosphere to obtain an H-type synthetic mordenite catalyst. Using this catalyst, in a fixed bed flow reactor, a raw material having a composition shown in Table 1 containing a benzene distillate obtained by distilling gasoline as a raw material and an aromatic hydrocarbon having 9 or more carbon atoms was distilled. Table 1 shows the result of contacting the non-aromatic compound after removal.
Was obtained, and aromatic hydrocarbons having 7 and 8 carbon atoms were removed by distillation. The reaction conditions are as follows.

Reaction conditions: temperature 400 ° C. pressure 2.5 MPa- ^G liquid space velocity 2.3 h ⁻¹ hydrogen / raw material 4.0 mol / mol The hydrogen consumption in the reaction is 0.84 wt% based on the raw material, and the catalyst deterioration rate Is determined based on the xylene concentration in the product.
It was 04 wt% / 100 hours.

[0039]

[Table 1]

Comparative Example 1 The results of contacting the raw materials without distillation under the conditions of Example 1 are shown in Table 2. The hydrogen consumption in the reaction was 1.1
4 wt%, and the catalyst deterioration rate was -0.08 wt% / 100 hours.

[0041]

[Table 2]

[0042]

According to the present invention, by contacting an aromatic compound using an aromatic hydrocarbon raw material containing benzene having a non-aromatic compound content of 1% by weight or less with a catalyst, hydrogen consumption and catalyst can be reduced. The activity can be suppressed, and conversion to useful aromatic hydrocarbons such as toluene and xylene can be achieved.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C10G 35/085 C10G 35/085 35/095 35/095 // C07B 61/00 300 C07B 61/00 300

Claims (9)

[Claims] (1) a non-aromatic compound containing benzene and
A method for converting aromatic hydrocarbons, comprising contacting a catalyst with an aromatic hydrocarbon of not more than wt%. 2. The aromatic hydrocarbon according to claim 1, wherein the conversion is performed after removing the non-aromatic compound to 1 wt% or less from the crude aromatic hydrocarbon material containing benzene and the non-aromatic compound. How to convert hydrogen. 3. The method for converting an aromatic hydrocarbon according to claim 1, wherein the conversion of the aromatic hydrocarbon is a transalkylation reaction. 4. The method for converting aromatic hydrocarbons according to claim 1, wherein hydrogen is present in the reaction system. 5. The method according to claim 1, wherein the raw material contains an alkyl aromatic hydrocarbon having 9 or more carbon atoms.
The method for converting aromatic hydrocarbons according to the above item. 6. The method according to claim 5, wherein benzene and aromatic hydrocarbons having 9 or more carbon atoms in the raw material are reduced, and aromatic hydrocarbons having 7 or 8 carbon atoms in the product are increased. A method for converting aromatic hydrocarbons. 7. The process for converting aromatic hydrocarbons according to claim 1, wherein the catalyst comprises zeolite. 8. The catalyst according to claim 6, wherein the catalyst is a group VIB, VIIB,
The method for converting aromatic hydrocarbons according to any one of claims 1 to 7, wherein the method includes at least one of Group VIII metals. 9. The process for converting aromatic hydrocarbons according to claim 1, wherein the catalyst comprises mordenite and rhenium.