Method for producing monocyclic aromatic hydrocarbon having 6-8 carbon atoms

Abstract

A method for producing a monocyclic aromatic hydrocarbon having 6 to 8 carbon atoms, including bringing a raw material which contains a light hydrocarbon having 2 to 7 carbon atoms as a main component into contact with a catalyst composition for producing a monocyclic aromatic hydrocarbon having 6 to 8 carbon atoms. The catalyst composition for producing a monocyclic aromatic hydrocarbon having 6 to 8 carbon atoms is coated with an amorphous silicon oxide compound and contains a crystalline aluminosilicate, and the silicon oxide compound is a silicon oxide compound derived from a compound represented by X.sub.nSi(OR).sub.4-n, where X represents a hydrogen atom or an alkyl group, R represents an alkyl group, and n represents an integer of 0 to 4.

Claims

1. A method for producing a monocyclic aromatic hydrocarbon having 6 to 8 carbon atoms, the method comprising: heating and stirring a catalyst containing a crystalline aluminosilicate and a compound represented by General Formula (1) in a nitrogen atmosphere at 50° C. to 110° C., followed by heat treatment at 300° C. to 600° C. in the presence of oxygen, to obtain a catalyst composition coated with an amorphous silicon oxide compound, and bringing a raw material which contains a light hydrocarbon having 2 to 7 carbon atoms as a main component into contact with the catalyst composition to produce a monocyclic aromatic hydrocarbon having 6 to 8 carbon atoms; wherein the compound represented by Formula (1) is:
X.sub.nSi(OR).sub.4-n   (1) wherein X represents a hydrogen atom or an alkyl group, R represents an alkyl group, and n represents an integer of 0 to 4.

2. The method for producing a monocyclic aromatic hydrocarbon having 6 to 8 carbon atoms according to claim 1, wherein a molar ratio of an acid quantity of the catalyst composition to Al is 1.25 or less, the acid quantity being defined by an amount of ammonia desorbed in a temperature range of 200° C. to 500° C. in an NH.sub.3-TPD method.

3. The method for producing a monocyclic aromatic hydrocarbon having 6 to 8 carbon atoms according to claim 1, wherein the crystalline aluminosilicate is a pentasil zeolite.

4. The method for producing a monocyclic aromatic hydrocarbon having 6 to 8 carbon atoms according to claim 3, wherein the crystalline aluminosilicate is an MFI zeolite.

5. The method for producing a monocyclic aromatic hydrocarbon having 6 to 8 carbon atoms according to claim 1, wherein a content of gallium with respect to 100 parts by mass of the catalyst composition for producing a monocyclic aromatic hydrocarbon is 0.1 parts by mass or more and 10.0 parts by mass or less.

6. The method for producing a monocyclic aromatic hydrocarbon having 6 to 8 carbon atoms according to claim 1, wherein the crystalline aluminosilicate contains gallium, and a molar ratio (Ga/Al) of gallium to aluminum is 0.1 or more and 10.0 or less.

Description

EXAMPLES

(1) Hereinafter, the present invention will be more specifically described according to Examples, but the present invention is not limited to Examples below.

Synthesis Example

(2) (Production Example 1)

(3) Using 5 g of ZSM-5 (an ammonium type, Si/Al=35 mol/mol), baking was performed at 500° C. for 5 hours under air flow to obtain ZSM-5 (a proton type). Subsequently, 0.37 g of gallium nitrate was dissolved in 70 ml of distilled water and suspended so that an aqueous solution of 3.0% by mass (a value in a case where the total mass of ZSM-5 was 100% by mass) of gallium was ion-exchanged (or impregnated and supported) and stiffed at 80° C. for 24 hours. Then, baking was performed at 500° C. for 3 hours under air flow, thereby obtaining a gallium-containing crystalline aluminosilicate. As a surface acidic point treatment, the gallium-containing crystalline aluminosilicate was stirred in tetramethoxysilane and hexane, refluxed for 1 hour, and then subjected to heating treatment at 600° C. Tableting molding was performed by applying a pressure of 39.2 MPa (400 kgf) and coarse pulverization was performed to make a granular material having a size of 20 to 28 meshes, thereby obtaining a crystalline aluminosilicate 1 (a catalyst composition 1) containing gallium. This crystalline aluminosilicate 1 was used as a catalyst composition for producing a monocyclic aromatic hydrocarbon having 6 to 8 carbon atoms in Example 1.

Production Example 2

(4) A catalyst composition 2 was obtained in the same manner as in Production example 1 except that ZSM-5 having Si/Al=60 mol/mol was used.

Comparative Production Example

(5) A comparative catalyst composition 1 was obtained in the same manner as in Production example 1 except that the surface acidic point treatment was not performed.

Comparative Production Example 2

(6) A comparative catalyst composition 2 was obtained in the same manner as in Production example 2 except that the surface acidic point treatment was not performed.

(7) <NH.sub.3-TPD Measurement>

(8) As a pretreatment, helium was made to flow to 30 mg of the sample at 30 mL/min, and the temperature was raised to 500° C. at a temperature raising rate of 10° C/min and held for 1 hour. After holding for 1 hour, the temperature was lowered to 100° C. under helium flow, and then ammonia (5% helium balance) was made to flow at 30 mL/min and held at 100° C. for 30 minutes. Next, helium was made to flow at 30 mL/min while being held at 100° C. to replace the inside of the system for 10 minutes, and then TPD measurement was performed while raising the temperature to 600° C. at a temperature raising rate of 10° C/min under a helium flow of 30 mL/min. The measurement results of the NH.sub.3 acid quantity are shown in Table 1. It is noted that Al in the table was calculated from the atomic weight of each element assuming that the composition of ZSM-5 was H.sup.+n(H.sub.2O).sub.16[Al.sub.nSi.sub.96-nO.sub.192].

(9) TABLE-US-00001 TABLE 1 Comparative Comparative catalyst Catalyst catalyst Catalyst Catalyst composition composition composition composition composition 1 1 2 2 Si/Al 35 35 60 60 Acidic point No Yes No Yes treatment Al 0.42 mmol/g 0.42 mmol/g 0.25 mmol/g 0.25 mmol/g NH.sub.3 acid 0.55 mmol/g 0.44 mmol/g 0.37 mmol/g 0.30 mmol/g quantity NH.sub.3 acid 1.31 1.05 1.48 1.20 quantity/Al
<BTX Yield (1)>

Examples 1 to 2 and Comparative Examples 1 and 2

(10) Using a flow type reaction device having a reactor which was filled with 5 mL of the catalyst composition of each of Production Examples 1 and 2 and Comparative Production Examples 1 and 2, butene was brought into contact with the catalyst composition to be reacted under the conditions of a reaction temperature of 550° C. and a reaction pressure of 0.1 MPaG. At that time, nitrogen was introduced as a diluent so that the contact time between the raw material oil and the catalyst was 6.4 seconds.

(11) The reaction was carried out under these conditions for 30 minutes to produce a monocyclic aromatic hydrocarbon having 6 to 8 carbon atoms, the composition of the product was analyzed by an FID gas chromatograph directly connected to the reaction device, and the yield of the monocyclic aromatic hydrocarbon having 6 to 8 carbon atoms was measured. The measurement results are shown in Table 2.

(12) TABLE-US-00002 TABLE 2 Comparative Comparative Example 1 Example 1 Example 2 Example 2 Catalyst Comparative Catalyst Comparative Catalyst com- catalyst composition catalyst composition position composition 1 1 composition 2 2 Si/Al 35 35 60 60 Acidic No Yes No Yes point treatment BTX yield 60 mass % 64 mass % 53 mass % 65 mass %

(13) As shown in Table 2, in Example 1 to which the present invention was applied, the BTX yield was high as compared with that of Comparative Example 1 in which the comparative catalyst composition 1 which was not subjected to the acidic point surface treatment was used. In addition, in Example 2 to which the present invention was applied, the BTX yield was high as compared with that of Comparative Example 2 in which the comparative catalyst composition 2 which was not subjected to the acidic point surface treatment was used.

(14) <BTX yield (2)>

Example 3 and Comparative Example 3

(15) The yield of the monocyclic aromatic hydrocarbon having 6 to 8 carbon atoms was measured in the same manner as in the above-described “BTX yield (1)” except that butane was used instead of butene. The measurement results are shown in Table 3.

(16) TABLE-US-00003 TABLE 3 Comparative Example 3 Comparative Example 3 Catalyst catalyst Catalyst composition composition 1 composition 1 Si/Al 35 35 Acidic point No Yes treatment BTX yield 50 mass % 52 mass %

(17) As shown in Table 3, in Example 3 to which the present invention was applied, the BTX yield was high as compared with that of Comparative Example 3 in which the comparative catalyst composition 1 which was not subjected to the acidic point surface treatment was used.

(18) <BTX yield (3)>

Example 4 and Comparative Example 4

(19) The yield of the monocyclic aromatic hydrocarbon having 6 to 8 carbon atoms was measured in the same manner as in the above-described “BTX yield (1)” except that a raw material oil 1 having the properties described in Table 4 was used instead of butene. The measurement results are shown in Table 5.

(20) TABLE-US-00004 TABLE 4 Light Term hydrocarbon Analysis method Density [g/cm.sup.3], 15° C. 0.6522 g/cm.sup.3 JIS K2249 Distillation property ° C. Distillation initial 34° C. JIS K2254 boiling point (IBP) 10% by volume 43° C. distilling temperature (T10) 90% by volume 64° C. distilling temperature (T90) Distillation end point 69° C. (EP) Composition vol % Normal paraffin (C4 to 47.91 vol % JIS K2536-2 C7) Total composition Isoparaffin (C4 to C7) 45.33 vol % analysis Olefins  0.01 vol % (gas Naphthenes  5.49 vol % chromatography) Monocyclic aromatics  1.27 vol %

(21) TABLE-US-00005 TABLE 5 Comparative Example 4 Comparative Example 4 Catalyst catalyst Catalyst composition composition 1 composition 1 Si/Al 35 35 Acidic point No Yes treatment BTX yield 58 mass % 61 mass %

(22) As shown in Table 5, in Example 4 to which the present invention was applied, the BTX yield was high as compared with that of Comparative Example 4 in which the comparative catalyst composition 1 which was not subjected to the acidic point surface treatment was used.

(23) The preferred Examples of the present invention have been described above, but the present invention is not limited to these Examples. Additions, omissions, substitutions, and other modifications of the configuration can be made without departing from the gist of the present invention. The present invention is not limited by the description described above and is limited only by the scope of the attached Claims.