CA2774686A1

CA2774686A1 - Method for producing monocyclic aromatic compound

Info

Publication number: CA2774686A1
Application number: CA2774686A
Authority: CA
Inventors: Satoshi Furuta
Original assignee: JX Nippon Oil and Energy Corp
Current assignee: Eneos Corp
Priority date: 2009-10-06
Filing date: 2010-10-05
Publication date: 2011-04-14
Anticipated expiration: 2030-10-05
Also published as: WO2011043066A1; JP5449383B2; CA2774686C; JPWO2011043066A1

Abstract

Provided is a method for producing a monocyclic aromatic compound wherein it is possible to effectively produce a monocyclic aromatic compound from a hydrocarbon oil containing a polycyclic aromatic compound, without using a high-pressure hydrogen gas. Specifically, provided is a method for producing a monocyclic aromatic compound from a hydrocarbon oil containing a polycyclic aromatic compound wherein water is added to the hydrocarbon oil containing a polycyclic aromatic compound, and the mixture of water and hydrocarbon oil is brought into contact with a catalyst containing at least titanium.

Description

SPECIFICATION
TITLE OF THE INVENTION: METHOD FOR PRODUCING MONOCYCLIC
AROMATIC COMPOUND

TECHNICAL FIELD

[0001] The present invention relates to a method for producing a monocyclic aromatic compound, and more particularly to a method for producing a monocyclic aromatic compound from a hydrocarbon oil containing a polycyclic aromatic compound, without supplying hydrogen from outside of the system.
BACKGROUND ART

[0002] Thermal cracking, hydrocracking and so on are conventionally known as a method for producing a monocyclic aromatic compound having only one aromatic ring, such as benzene, toluene and xylene, which is useful as a raw material of petrochemicals, from a polycyclic aromatic compound or a hydrocarbon oil containing a polycyclic aromatic compound (see, for example, Patent Document I and Patent Document 2 below).

[0003] However, the thermal cracking has a problem in that it does little to cause a cleavage of an aromatic ring, which results in insufficient production of a monocyclic aromatic compound. On the other hand, the hydrocracking has a problem in that it is costly because it uses high-pressure hydrogen gas in large quantities for cracking reaction and thus requires a large hydrogen gas production facility.

PRIOR ART DOCUMENTS
PATENT DOCUMENTS

[00041 Patent Document 1: JP-A-2003-96471 Patent Document 2: JP-A-2008-297452 SUMMARY OF THE INVENTION

PROBLEM TO BE SOLVED BY THE INVENTION

[0005] Therefore, it has been desired to develop a method for producing a monocyclic aromatic compound from a hydrocarbon oil containing a polycyclic aromatic compound that allows production of a monocyclic aromatic compound through a cleavage of an aromatic ring, without using high-pressure hydrogen gas.

MEANS FOR SOLVING THE PROBLEM

[0006] The inventor has made various studies and found that a monocyclic aromatic compound can be produced through a cleavage of an aromatic ring of a polycyclic aromatic compound, by contacting a catalyst containing titanium with a hydrocarbon oil containing a polycyclic aromatic compound in the presence of water, and as a result the present invention has been accomplished.

[0007] That is, an object of the present invention is to solve the aforementioned problem in an advantageous way, and the method for producing a monocyclic aromatic compound from a hydrocarbon oil containing a polycyclic aromatic compound according to the present invention comprises: adding water to the hydrocarbon oil containing the polycyclic aromatic compound; and contacting a mixture of the hydrocarbon oil and the water with a catalyst containing at least titanium. In this way, contacting the hydrocarbon oil with the catalyst containing at least titanium in the presence of the water enables the monocyclic aromatic compound to be produced through the cleavage of the aromatic ring of the polycyclic aromatic compound in the hydrocarbon oil, without adding hydrogen to the reaction system. As used herein, the term "monocyclic aromatic compound" refers to a compound that has only one aromatic ring, while the term "polycyclic aromatic compound" denotes a compound that has two or more aromatic rings (a condensed polycyclic aromatic compound and a non-condensed polycyclic aromatic compound). In addition, the term "catalyst containing at least titanium" denotes a catalyst that contains titanium element, such as a catalyst consisting only of metal titanium (Ti), a catalyst containing Ti and a catalyst containing titanium dioxide (TiO2).
[0008] Preferably, in the method for producing the monocyclic aromatic compound of the present invention, the hydrocarbon oil contains 10% by mass or more of a polycyclic aromatic compound. This is because the production method according to the present invention allows the monocyclic aromatic compound to be produced efficiently even from such a hydrocarbon oil that contains the polycyclic aromatic compound in an amount of 10% by mass or more. Additionally, for example, the amount of the polycyclic aromatic compound in the hydrocarbon oil can be measured by a gas chromatograph and so on.

[0009] In addition, in the method for producing the monocyclic aromatic compound of the present invention, the hydrocarbon oil may also contain a sulfur component and/or a nitrogen component. According to the production method of the present invention, even if the hydrocarbon oil contains a sulfur component and/or a nitrogen component, the sulfur component and/or the nitrogen component can be removed from the hydrocarbon oil, by contacting the hydrocarbon oil with the catalyst containing at least titanium in the presence of water, without adding hydrogen to the reaction system. Therefore, even if the hydrocarbon oil used as a raw material contains a sulfur component and/or a nitrogen component, at least a part of the sulfur component and/or the nitrogen component can be removed from a generated oil containing the monocyclic aromatic compound produced by contacting the mixture with the catalyst. As used herein, the term "sulfur component" means a sulfur component that can be measured by ICP analysis, GC-SCD and so on, while the term "nitrogen component" denotes a nitrogen component that can be measured by ICP analysis, GC-NPD and so on.

[0010] Further, in the method for producing the monocyclic aromatic compound of the present invention, contacting the mixture with the catalyst is preferably performed under conditions that a temperature is 300-600 C, a pressure is 0.5-50 MPa and a liquid hourly space velocity is 0.01-10 h-'. This is because assuming such conditions are met, aromatic rings of the polycyclic aromatic compound can be cleaved efficiently.
EFFECT OF THE INVENTION

[0011] According to the method for producing the monocyclic aromatic compound of the present invention, the monocyclic aromatic compound can be produced efficiently from the hydrocarbon oil containing the polycyclic aromatic compound, without using high-pressure hydrogen gas. In addition, according to the method for producing the monocyclic aromatic compound of the present invention, the monocyclic aromatic compound can be produced efficiently even if the hydrocarbon oil used contains the sulfur component and/or the nitrogen component, while the sulfur component and/or the nitrogen component can be removed efficiently from the generated oil, without using high-pressure hydrogen gas.

-4-BEST MODE FOR CARRYING OUT THE INVENTION
[0012] Embodiments of the present invention will now be described in detail below. It should be noted here that the method for producing the monocyclic aromatic compound of the present invention is a method for producing a monocyclic aromatic compound from a hydrocarbon oil containing a polycyclic aromatic compound. Then, according to the method for producing the monocyclic aromatic compound of the present invention, the monocyclic aromatic compound is produced through the cleavage of aromatic rings of the polycyclic aromatic compound in the hydrocarbon oil, by adding water to the hydrocarbon oil containing the polycyclic aromatic compound, and contacting the resulting mixture of the hydrocarbon oil and the water with a catalyst containing at least titanium.
[0013] As used herein, the polycyclic aromatic compound includes, e.g., a condensed polycyclic aromatic compound such as 1-methylnaphthalene, quinoline, anthracene and phenanthrene, as well as a non-condensed polycyclic aromatic compound such as dibenzothiophen and biphenyl. In addition, the hydrocarbon oil containing the polycyclic aromatic compound includes, e.g., an atmospheric residue, a vacuum residue and a vacuum gas oil (VGO) which are obtained during oil refining, as well as fractions (LCO, DO) having a boiling point of 180 C or above which are obtained from a fluid catalytic cracking unit.
It should be noted that from the viewpoint of efficient production of the monocyclic aromatic compound, the polycyclic aromatic compound is preferably contained in the hydrocarbon oil in an amount of 10% by mass or more, more preferably 15% by mass or more, and particularly preferably 20% by mass or more.
[0014] In addition, when the above-described hydrocarbon oil contains sulfur and nitrogen components, the sulfur component includes a sulfur component that is contained in the hydrocarbon oil in the form of, e.g., dibenzothiophen, benzothiophene, sulfide and so on, and that can be measured by ICP analysis, GC-SCD and so on. A sulfur content in the hydrocarbon oil maybe 0.1% by mass or more, but preferably not more than 5.0% by mass. On the other hand, the nitrogen component includes a nitrogen component that is contained in the hydrocarbon oil in the form of, e.g., quinoline, carbazole and so on, and that can

-5-be measured by ICP analysis, GC-NPD and so on. A nitrogen content in the hydrocarbon oil may be 0.1 % by mass or more, but preferably not more than 1.0% by mass.

[0015] The production method of the present invention also uses water as a source of hydrogen when cleaving aromatic rings of a polycyclic aromatic compound (ring-opening reaction). In addition, the water only needs to be added to the hydrocarbon oil in an amount sufficient to cause the cleavage of the aromatic rings of the polycyclic aromatic compound. For example, the water may be added in an amount of 10-3000 parts by mass, preferably 10-2000 parts by mass, more preferably 10-1000 parts by mass, per 100 parts by mass of the hydrocarbon oil. This is because if the water is added in an amount of less than 10 parts by mass per 100 parts by mass of the hydrocarbon oil, the rate of ring-opening reaction may be reduced and the cleavage of the aromatic rings may not proceed enough. On the other hand, if the water is added in an amount more than 3000 parts by mass, an amount of water that does not contribute to the production (ring-opening reaction) of the monocyclic aromatic compound may increase, and this may result in increased cost and less efficient production of the monocyclic aromatic compound.

[0016] In addition, if the above-described hydrocarbon oil contains the sulfur component and/or the nitrogen component, the water also serves as a source of hydrogen when removing the sulfur component and/or the nitrogen component in the hydrocarbon oil as hydrogen sulfide and/or ammonia through a hydrogenation reaction. It should be noted here that from the viewpoint of efficient removal of the sulfur component and/or the nitrogen component, the water is preferably added to the hydrocarbon oil in an amount between 10-3000 parts by mass, more preferably 10-2000 parts by mass, and particularly preferably 10-1000 parts by mass, per 100 parts by mass of the hydrocarbon oil. By adding the water in an amount of 10 parts by mass or more per 100 parts by mass of the hydrocarbon oil, it becomes possible to remove the sulfur component and/or the nitrogen component at a sufficient desulfurization rate and/or denitrification rate. In addition, by adding water in an amount of 3000 parts by mass or less, it becomes possible to avoid increase in cost and decrease in desulfurization/denitrification efficiency, while suppressing the amount of water that does not contribute to the

-6-hydrogenation reaction (desulfurization and denitrification).

[0017] Used as the catalyst containing at least titanium (which may be hereinafter referred to as a "titanium-containing catalyst") may be a catalyst containing titanium element, such as a catalyst consisting only of metal titanium (Ti), a catalyst containing Ti and a catalyst containing titanium dioxide (Ti02).
Specifically, for example, the following catalysts may be used: a catalyst consisting only of metal titanium; a catalyst of a titanium alloy; a catalyst having its surface coated with titanium using a technique such as plating, deposition and so on; and a catalyst produced by a coprecipitation method and containing a composite oxide of Ti02 and an oxide of a metal in the third and forth periods of the periodic table (except alkali metal and alkaline-earth metal) such as and Fe203. Besides, the Ti02 used as a catalyst may have any crystal structure.
In addition, the above-described titanium-containing catalyst preferably contains Ti in an amount of 5-100% by mass as Ti element, more preferably 10-80% by mass, and particularly preferably 20-60% by mass. By using the catalyst containing Ti in an amount of 5% by mass or more as Ti element, it becomes possible to produce the monocyclic aromatic compound more efficiently by causing the cleavage of the aromatic rings of the polycyclic aromatic compound in the hydrocarbon oil in a more efficient manner. In addition, if the hydrocarbon oil contains the sulfur component and/or the nitrogen component, the use of the catalyst containing Ti in an amount of 5% by mass or more as Ti element enables the monocyclic aromatic compound to be produced efficiently, while removing the sulfur component and/or the nitrogen component from the generated oil in a more efficient manner.
[0018] In addition, according to the method for producing the monocyclic aromatic compound of the present invention, the monocyclic aromatic compound is produced by contacting, e.g., the mixture of the hydrocarbon oil containing the polycyclic aromatic compound and the water with the titanium-containing catalyst loaded in a reactor. In this case, for example, the mixture and the catalyst may be brought into contact with each other in the reactor under conditions that a temperature is 300-600 C, preferably 400-550 C, a pressure is 0.5-50 MPa, preferably 1.0-40 MPa, and a liquid hourly space velocity is 0.01-h-', preferably 0.08-10 h-1. This is because below a temperature of 300 C, the

-7-ring-opening reaction and hydrogenation reaction (desulfurization and denitrification) may not proceed enough since the activation energy required for the reaction cannot be obtained; whereas above 600 C, unwanted gas (methane, ethane, etc.) may be generated in large quantities and the yield of the monocyclic aromatic compound may be reduced, which could be economically disadvantageous. In addition, this is because below a pressure of 0.5 MPa, it may be difficult to make the hydrocarbon oil and the water flow into a reactor smoothly; whereas above 50 MPa, the cost of producing a reactor may increase.
Furthermore, this is because below a liquid hourly space velocity of 0.01 h-1, generation of unwanted gas may become dominant and the yield of the monocyclic aromatic compound may be reduced, or if the hydrocarbon oil contains the sulfur component and/or the nitrogen component, desulfurization/denitrification efficiency may decrease; whereas above 10 h"1, the reaction time may be too short and the ring-opening reaction and hydrogenation reaction (desulfurization and denitrification) may not proceed enough.
[00191 Additionally, the method for producing the monocyclic aromatic compound of the present invention eliminates the need to supply hydrogen from outside of the system, because hydrogen required for the ring-opening reaction of the polycyclic aromatic compound is supplied from the water. Also, it is not necessary to add hydrogen from outside of the system even if the hydrocarbon oil contains the sulfur component and/or the nitrogen component, because the water is utilized as a source of hydrogen required for desulfurization and denitrification (hydrogenation reaction). Thus, according to the method for producing the monocyclic aromatic compound of the present invention, a molar ratio of hydrogen added from outside of the system to the hydrocarbon oil supplied (the amount of hydrogen added/the amount of the hydrocarbon oil supplied) may be equal to or less than 0.1, preferably 0. Therefore, according to the method for producing the monocyclic aromatic compound of the present invention, the monocyclic aromatic compound can be produced efficiently from the hydrocarbon oil containing the polycyclic aromatic compound, without using high-pressure hydrogen gas. In addition, even if the hydrocarbon oil as the raw material contains the sulfur component and/or the nitrogen component, the sulfur component and/or the nitrogen component can be removed efficiently from the

-8-generated oil containing the monocyclic aromatic compound as a target product.
[00201 It should be noted here that the method for producing the monocyclic aromatic compound of the present invention uses the titanium-containing catalyst as a catalyst, rather than hydrothermally synthesized zeolite, y-alumina or the like which is used for hydrocracking reaction of a hydrocarbon oil. Accordingly, even if the ring-opening reaction is carried out in the presence of water, there is no possibility that the catalyst becomes no longer available due to significant changes in its crystal structure in a high-temperature, high-pressure steam.
In addition, the catalyst is less susceptible to degradation, which avoids the need to pretreat the hydrocarbon oil.
EXAMPLES
[0021] The present invention will now be described in more detail below with reference to examples thereof. However, the present invention is in no way limited to the examples disclosed herein.

[00221 (Example 1) As a titanium-containing catalyst, 24.5 g of globular titanium (manufactured by Ayumi Seisakusho, purity: 99.8%, particle size: 2 mm) is loaded into a reactor (internal volume: 10 ml), which is made of a superalloy (Inconel 625). Then, water is introduced into the reactor loaded with the titanium-containing catalyst, and the reactor is heated and pressurized up to a temperature of 468 C and a pressure of 28 MPa. Thereafter, without adding hydrogen, a hydrocarbon oil with the composition shown in Table 1 and water are flown through the reactor (at a liquid hourly space velocity of 0.6 h-1), respectively, at a flow rate of 0.1 ml/min (at a ratio of 1 part by mass of water to 0.85 part by mass of a hydrocarbon oil).

Subsequently, after 4 hours from the start of the oil flow, the reaction product is obtained and the conversion and so on of each compound in the hydrocarbon oil are calculated by the following methods. The results are shown in Table 2.

-9-[0023] [Table 1]
Compound Content [% by mass]
1-methylnaphthalene 27.7 Decalin 26.4 Dodecylbenzene 41.2 dibenzothiophen * 1 1.8 quinoline *2 2.3 * 1 sulfur content in hydrocarbon oil: 0.31 % by mass *2 nitrogen content in hydrocarbon oil: 0.25% by mass [0024] (Calculation of Conversion and so on) The reaction product is analyzed using a gas chromatograph (manufactured by Shimadzu Corporation, GC14-B, column DB-1 60 m). The conversion is calculated from the peak area of each compound remaining in the reaction product.

In addition, the mass ratios of benzene and C 1-C5 benzenes (benzene derivatives, each having a hydrocarbon group bonded to a benzene ring and containing a total of 1-5 carbons) in the reaction product to the mass of liquid of the obtained reaction product are determined by the gas chromatograph and taken as the yields of the benzene and CI-C5 benzenes. Besides, the yields of the C2-C5 benzenes are determined by using the total amount of isomers.
[0025] (Calculation of Removal Rate) The reaction product is analyzed by ICP analysis. The sulfur component remaining in the reaction product is quantified to calculate the removal rate of sulfur content.

In addition, the reaction product is analyzed using a gas chromatograph (manufactured by Shimadzu Corporation, GC14-B, column DB-1 60 m). The conversion is calculated from the peak area of quinoline and taken as the removal rate of nitrogen content. At this moment, it was also confirmed using the gas chromatograph that the C3 benzene, the product of the denitrification reaction of quinoline is obtained quantitatively.
[0026] (Example 2) Water and a hydrocarbon oil are flown through the reactor in the same manner as described in Example 1, except that a composite oxide of

-10-TiO2/A12O3 (manufactured by Ishihara Sangyo Kaisha, Ltd., TiO2: 88% by mass, A1203: 12% by mass, Ti element: 42% by mass), which is prepared by a coprecipitation method, is used as a titanium-containing catalyst.
Then, the conversion and so on of each compound in the hydrocarbon oil are calculated in the same way as described in Example 1. The results are shown in Table 2.
In addition, the resulting product is analyzed to calculate its material balance, the results of which are shown in Table 3.

[0027] (Comparative Example 1) Water and a hydrocarbon oil are flown through a reactor in the same manner as described in Example 1, except that they are flow though the reactor at a flow rate of 0.23 ml/min respectively so that they can be retained in the reactor for the same period of time as in Examples 1 and 2 without loading a titanium-containing catalyst.

Then, the conversion and so on of each compound in the hydrocarbon oil are calculated in the same way as described in Example 1. The results are shown in Table 2.

[0028] (Comparative Example 2) Water and a hydrocarbon oil are flown through a reactor in the same manner as described in Example 1, except that a composite oxide of CeO2-Fe2O3/ZrO2 (manufactured by Daiichi Kigenso Kagaku Kogyo Co., Ltd., CeO2:
59% by mass, Fe2O3: 20% by mass, ZrO2: 21% by mass) is used as a catalyst.

Then, the conversion and so on of each compound in the hydrocarbon oil are calculated in the same way as described in Example 1. The results are shown in Table 2.

-11-[0029] [Table 2]
Comp. Ex. I Ex. 1 Ex. 2 Comp. Ex. 2 Catalyst none titanium TiO2/AI2O3 Ce02-Fe2O3/ZrO2 conversion of 0% 95.0% 93.7% 57.8%
1-m ethyl naphthalene conversion of decalin 0% 89.1% 94.8% 61.8%
conversion of 43.6% 96.8% 97.1% 77.8%
dodecylbenzene conversion of 0% 100% 94.5% 59.8%
dibenzothiophen conversion of 57.0% 89.8% 96.3% 94.5%
quinoline yields of benzene and C1-C5 benzenes in 9.6% 84.1% 85.4% 47.4%
the reaction product removal rate of 0% 91.1% 89.3% 70.9%
sulfur content removal rate of 57.0% 89.8% 96.3% 91.7%
nitrogen content [0030] [Table 3]
Raw Material [% by mass] Product [% by mass]
1-methylnaphthalene 27.69 2.15 decalin 26.38 2.35 dodecylbenzene 41.24 1.30 dibenzothiophen 1.77 0.15 quinoline 2.35 0.00 C5 benzene - 32.65 C4 benzene - 39.68 C3 benzene - 1.74 water 14.04 *3 0.00 hydrogen sulfide - 0.35 ammonia - 0.26 hydrogen - 0.94 methane - 14.91 CO2 - 17.01 *3 value calculated from generated CO2

-12-[0031] From the yields of the benzene and C1-C5 benzenes in the reaction product as shown in Table 2, it can be seen that the monocyclic aromatic compound can be produced efficiently in Example 1 and 2. From Examples 1 and 2 as well as Comparative Examples 1 and 2 in Table 2, it can also be seem that the use of the catalyst containing titanium allows the sulfur and nitrogen components to be removed from the hydrocarbon oil efficiently without adding hydrogen from outside of the system, and that the cleavage of the aromatic ring of the polycyclic aromatic compound in the hydrocarbon oil can be caused so that the monocyclic aromatic compound can be produced efficiently.

[0032] In addition, from the results on the material balance of Example 2 shown in Table 3, it can be seen that hydrogen atoms in the water are used as a source of hydrogen, while oxygen atoms in the water contributes to the generation of CO2.

INDUSTRIAL APPLICABILITY

[0033] According to the present invention, the monocyclic aromatic compound can be produced efficiently from the hydrocarbon oil containing the polycyclic aromatic compound, without using high-pressure hydrogen gas. In addition, according to the present invention, even if the hydrocarbon oil used contains the sulfur component and/or the nitrogen component, the monocyclic aromatic compound can be produced efficiently without using high-pressure hydrogen gas, while removing the sulfur component and/or the nitrogen component from the generated oil in an efficient manner.

Claims

1. A method for producing a monocyclic aromatic compound from a hydrocarbon oil containing a polycyclic aromatic compound, the method comprising:
adding water to the hydrocarbon oil containing the polycyclic aromatic compound; and contacting a mixture of the hydrocarbon oil and the water with a catalyst containing at least titanium.

2. The method for producing the monocyclic aromatic compound according to claim 1, wherein the hydrocarbon oil contains the polycyclic aromatic compound in an amount of 10% by mass or more.

3. The method for producing the monocyclic aromatic compound according to claim 1 or 2, wherein the hydrocarbon oil contains a sulfur component and/or a nitrogen component.

4. The method for producing the monocyclic aromatic compound according to claim 3, wherein at least a part of the sulfur component and/or the nitrogen component is removed from a generated oil containing the monocyclic aromatic compound produced by contacting the mixture with the catalyst.

5. The method for producing the monocyclic aromatic compound according to any one of claims 1-4, wherein contacting the mixture with the catalyst is performed under conditions that a temperature is 300-600°C, a pressure is 0.5-50 MPa and a liquid hourly space velocity is 0.01-10 h-1.