JP2002037782A - Method for separating methylbenzothiophene and methylnaphthalene - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently adsorb and separate methylbenzothiophene and methylnaphthalene from a mixture comprising both the components. SOLUTION: A faujasite type zeolite subjected to ion exchange with a metal belonging to group IIa of the periodic table is used as an adsorbent when the methylbenzothiophene and methylnaphthalene are adsorbed and separated from the mixture comprising both the components. In the process, a 6-10C aromatic hydrocarbon is advantageously used as an eliminating agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for separating or recovering methylbenzothiophene and methylnaphthalene from a mixture containing methylbenzothiophene and methylnaphthalene by an adsorption separation method.

[0002]

2. Description of the Related Art Methylbenzothiophene is a substance useful as a raw material for synthesis of pharmaceuticals, agricultural chemicals and the like. This methylbenzothiophene is contained in fractions derived from high-temperature pyrolysis of coal and petroleum, for example, coal tar fractions, fluid catalytic cracking oils, etc., and in particular, in the residual oil obtained by collecting methyl naphthalene from coal tar. It is concentrated and present in large quantities. Methylnaphthalene is also a useful substance, but there are many uses where it is not desired that a sulfur compound is present as an impurity.

[0003] However, taking coal tar distillation as an example, methylbenzothiophenes are contained in a large amount in a methylnaphthalene fraction. Is difficult to separate or recover. Also,
The crystallization method, which is an industrial separation technique, is similarly difficult.

On the other hand, as a method of separating benzothiophene having a structural similarity by adsorption separation, there is a method of using polyethylene glycol-supported alumina as an adsorbent (German Patent No. 72-2329392). Glycol is eluted, resulting in poor separation efficiency. Further, a method using palladium chloride-supported silica gel (Fuel, 1986, 65, p270) and a method using metal-exchanged X-type zeolite as an adsorbent (Kok)
s. Khimm, 1985, 8, p35, USSR11
No. 74424) and a method using a faujasite type zeolite such as a method using a metal-exchanged Y-type zeolite (Japanese Patent Application Laid-Open No. 9-151139). Not.

[0005]

An object of the present invention is to provide an industrial method for efficiently separating or recovering both components from a mixture containing such methylbenzothiophene and methylnaphthalene.

[0006]

That is, the present invention uses a faujasite type zeolite as an adsorbent from a mixture containing methylbenzothiophene and methylnaphthalene, and adsorbs and separates both components from benzothiophene and naphthalene. It is a separation method or a recovery method.

The adsorbent used in the present invention is a faujasite type zeolite. The faujasite-type zeolite is a crystalline aluminosilicate represented by the following formula. 0.9 ± 0.2 M _{2 / n} O: Al ₂ O ₃ : xSiO ₂ : y
H ₂ O where M represents a cation and n represents its valence. The above-mentioned faujasite type zeolite is X type and Y type
The X type is represented by x = 2.5 ± 0.5, and the Y type is represented by x = 3 to 6. Further, y differs depending on the degree of hydration.

In the present invention, it is preferable to use X-type and Y-type faujasite zeolites, particularly Y-type faujasite zeolites.
Jasite zeolite is the preferred adsorbent.

[0009] The faujasite-type zeolite used in the present invention may be of the hydrogen ion or ammonium ion type, but is preferably one substituted with one or more metal ions. The metal ion may substitute a part or all of the cation, but is preferably one.
0% or more.

The metal ion to be substituted is preferably a metal belonging to Group Ia, Ib or IIa of the periodic table, and the ion is preferably a metal belonging to Group IIa. Beryllium, magnesium, calcium, strontium and barium are preferred. . Further, as a metal belonging to Group Ia, lithium, sodium, potassium and the like are preferable.
As a metal belonging to group b, copper and the like are preferable. More preferably, it is a metal belonging to Group IIa. Calcium and copper exhibit good separation performance.
When using ordinary commercial products, since these exist in the form of NaY and KY, it is preferable to partially or entirely replace this Na or K with the above-mentioned metal.
It is 10 to 100%, preferably 20 to 90%.

Particularly, as the adsorbent of the present invention, a Y-type faujasite-type zeolite substituted with calcium is preferable.

The method of ion exchange of these cations is carried out by bringing zeolite into contact with an aqueous solution of a water-soluble salt of the ion to be exchanged, for example, hydrochloride, nitrate, sulfate, carbonate or the like. The metal ion concentration of the aqueous solution varies depending on the type of the metal salt, but is preferably about 1 to 10% by weight. The method may be a batch type or a flow type. The contact may be repeated several times as necessary. The temperature at this time may be about 20 to 100 ° C. The amount of ion exchange varies depending on the type of ion, but can be arbitrarily set depending on the concentration of the solution, the temperature at the time of ion exchange, and the like.

The shape of the zeolite used in the present invention is as follows:
It is appropriately selected depending on the method of contacting the raw material to be separated with the zeolite, and may be a compression molded product, a molded product by a spray dryer, or a powder.

In addition, a desorbing agent is preferably used in the adsorption separation, and a known desorbing agent can be used as the desorbing agent. For example, ethers such as diethyl ether, isopropyl ether, n-propyl ether and anisole, esters such as ethyl acetate, n-propyl acetate, n-butyl acetate, isopropyl acetate and isobutyl acetate, acetone, methyl ethyl ketone and n-propyl ketone , Ketones such as cyclohexanone, alcohols such as methanol, ethanol, n-propyl alcohol, isopropyl alcohol and n-butanol, pyridine,
Pyridines such as 2-methylpyridine, 3-methylpyridine, 4-methylpyridine, 2,5-dimethylpyridine, 2,6-dimethylpyridine, acetonitrile, hexane,
Examples thereof include aliphatic hydrocarbons such as cyclohexane, heptane and octane, and aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, isopropylbenzene, diethylbenzene, tetralin, decalin, ethylbiphenyl and diethylbiphenyl.

Of these, aliphatic hydrocarbons and aromatic hydrocarbons or hydrides thereof are preferable, and particularly, C6 to C10 such as benzene, toluene, xylene, ethylbenzene, isopropylbenzene, tetralin and decalin.
Are most preferred.

The mixed oil containing methylbenzothiophene and methylnaphthalene has a boiling point of 2 obtained by distilling coal tar, coal liquefied oil, coal gasified distillate, etc.
A fraction containing a component in the range of 30 to 250 ° C. can be mentioned. This was further distilled and crystallized. The concentration may be increased, or may be obtained by another method. When recovering or purifying methylbenzothiophene or methylnaphthalene, the concentration of the target substance is preferably increased.
For example, the total concentration of the two is preferably set to 50 wt% or more. It is preferable that acidic components such as phenols, heavy components such as pitch, and tar bases such as quinoline be removed in advance. By the way, methylnaphthalene and methylbenzothiophene have isomers, but since there is no large difference in the adsorption characteristics between the isomers, a mixture of isomers may be used.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION To adsorb and separate methylbenzothiophene and methylnaphthalene using the adsorbent of the present invention, any of ordinary adsorption / separation operation, batch separation method or continuous separation method can be applied. . As an industrial separation operation, a so-called chromatographic preparative method may be used, or an adsorptive separation method using a simulated moving bed in which this is continuous may be used.

In the continuous adsorption separation method using a simulated moving bed, a plurality of adsorption units are installed, and the operations of adsorption, concentration, and desorption are performed in each column, and these columns are sequentially switched to perform each operation. Is an industrial process in which

First, a mixture containing methylbenzothiophene and methylnaphthalene, or a feedstock obtained by diluting the mixture with a diluent as required, is brought into contact with a beta-type zeolite adsorbent to selectively adsorb strongly adsorbed components. On the other hand, weakly adsorbed components are separated as raffinate (adsorption operation).
Next, the raffinate rich in weakly adsorbed components is further contacted with an adsorbent to adsorb the remaining strongly adsorbed components, and the weakly adsorbed components of the raffinate are concentrated (concentration operation). Further, the adsorbed strongly adsorbed component is desorbed from the adsorbent by the desorbing agent, and is collected as an extract together with the desorbing agent (desorption operation).

The adsorption / separation operation of the present invention can be carried out in either a gas phase or a liquid phase. However, it is preferable to carry out the adsorption / separation operation in a liquid phase because a lower temperature can suppress a side reaction. As operating conditions, the temperature ranges from room temperature to 200 ° C., preferably 50 to 150 ° C., and the pressure ranges from atmospheric pressure to 5 MPa.

The present invention can be applied to recovering or purifying either methylbenzothiophene or methylnaphthalene, or to separating, recovering or purifying both of them.

[0022]

The present invention will be described below in detail with reference to examples. The feedstock used in Examples and Comparative Examples was a methylnaphthalene fraction (hereinafter referred to as feedstock) obtained after acid extraction and distillation of coal tar oil, and its composition (% by weight) was as follows. Was. 1-methylnaphthalene: 19.3% 2-methylnaphthalene: 66.6% Dimethylnaphthalene: 0.7% Methylbenzothiophenes: 3.5% Biphenyl: 2.5% Indole: 0.3% Acenaphthene: 0. 1% Others: 6.3%

Example 1 A commercially available Na-substituted Y-type faujasite zeolite (silica / alumina ratio: 5.5, 0.4 mmφ molded product) was partially exchanged with calcium ions by an ion exchange method to obtain Ca.
(Na) Y-type zeolite was prepared. This is 350 ° C,
It was calcined for 4 hours and cooled in a desiccator. This adsorbent 2
0 g was packed in a steel cylindrical tube having a tube inner diameter of 8 mm and a length of 500 mm to form an adsorption column. Maintaining the column temperature at 50 ° C.
Toluene was supplied to the column at a rate of 5 ml / min as a desorbing agent, and packed into the column.

Next, the feedstock (as an internal standard substance,
(2% by weight of 1,3,5-triisopropylbenzene added)
Was supplied, followed by toluene at a rate of 1 ml / min for 60 minutes. At this time, the effluent was collected every 30 seconds and analyzed by gas chromatography. The results were plotted with time on the horizontal axis and analytical values on the vertical axis, and the point at which 2-methylnaphthalene and methylbenzothiophenes had the highest concentrations was measured as the retention time. Table 1 shows the results.
The larger the retention time difference between 2-methylnaphthalene and methylbenzothiophenes, the easier the separation. In addition,
Similarly, it was confirmed that not only 2-methylnaphthalene but also 1-methylnaphthalene could be separated.

Example 2 Using the Ca (Na) Y type zeolite prepared in Example 1, and using ethylbenzene as a desorbing agent, the retention time was measured in the same manner as in Example 1. Table 1 shows the results.

Example 3 The retention time was measured in the same manner as in Example 1 using the Ca (Na) Y type zeolite prepared in Example 1 and using tetralin as the desorbing agent. Table 1 shows the results.

Example 4 Using the Ca (Na) Y-type zeolite prepared in Example 1, and using para-xylene as a desorbing agent, the retention time was measured in the same manner as in Example 1. Table 1 shows the results.

Example 5 Using a Cu (Na) Y-type zeolite prepared in the same manner as in Example 1, using toluene as a desorbing agent, the retention time was measured in the same manner as in Example 1. Table 1 shows the results.

Example 6 Commercially available KY type zeolite (silica / alumina ratio: 5.
5, 0.4 mmφ molded product), and toluene was used as a desorbing agent, and the retention time was measured in the same manner as in Example 1. Table 1 shows the results.

Example 7 A commercially available NaY-type zeolite (silica / alumina ratio: 5.
5, 0.4 mmφ molded product), and toluene was used as a desorbing agent, and the retention time was measured in the same manner as in Example 1. Table 1 shows the results.

Example 8 Commercially available NaX type zeolite (silica / alumina ratio: 3.
Using 5), the retention time was measured in the same manner as in Example 1 using toluene as the desorbing agent. Table 1 shows the results.

Comparative Example 1 Using a commercially available NaA-type zeolite and using ethylcyclohexane as a desorbing agent, the retention time was measured in the same manner as in Example 1. Both the retention times of 2-methylnaphthalene and methylbenzothiophenes were 3.0 minutes, the same value, and it was found that they were not separated at all.

[0033]

[Table 1]

[0034]

According to the separation method of the present invention, both components can be efficiently adsorbed and separated from a mixture containing methylbenzothiophene and methylnaphthalene, and purification or recovery of methylbenzothiophene and / or methylnaphthalene can be performed. It is effective for

Continued on the front page (72) Katsuhide Noguchi Inventor Katsuhide No. 80, 46, Nakahara-San, Tobata-ku, Kitakyushu-shi, Fukuoka F-term in Nippon Steel Chemical Research Laboratories (reference) GA11 4H006 AA02 AD17 BB11 DA15 DA35

Claims (4)

[Claims] 1. A method for separating methylbenzothiophene and methylnaphthalene, comprising using a faujasite-type zeolite as an adsorbent when adsorbing and separating both components from a mixture containing methylbenzothiophene and methylnaphthalene. Method. 2. The method for separating methylbenzothiophene and methylnaphthalene according to claim 1, wherein a faujasite-type zeolite ion-exchanged with a metal belonging to Group Ia, Ib or IIa of the periodic table is used as the adsorbent. . 3. The methylbenzothiophene according to claim 1, wherein an aliphatic hydrocarbon having 6 to 10 carbon atoms, an aromatic hydrocarbon or a hydride thereof is used as a desorbing agent in the adsorption separation. A method for separating methylnaphthalene. 4. A method according to claim 1, wherein one or both of methylbenzothiophene and methylnaphthalene are recovered from a mixture containing methylbenzothiophene and methylnaphthalene. A method for recovering methylbenzothiophene or methylnaphthalene.