JPH10265416A - Separation and recovery of benzothiophene and naphthalene - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently separate and recover benzothiophene and naphthalene, respectively, from their mixture by employing a faujasite type zeolite exchanged with the ion of lithium or a metal belonging to the IIa group in the periodic table as an adsorbent. SOLUTION: The faujasite type zeolite is expressed by the formula: 0.9±0.2M2/n O: Al2 O3 : xSiO2 : yH2 O [M is a cation; (n) is the atomic valency of the M], and is preferably replaced with one or more kinds of metal ions. The Y type zeolite is preferable among the X type zeolite and the Y type zeolite. The amount of the replaced metal ion is preferably >=10%. The replaced metal ion is preferably Li ion or the ion of a metal, such as Mg or Ca, belonging to the IIa group in the periodic table. The exchange of the cation is carried out by bringing the aqueous solution of the water-soluble salt of the exchanging ion into contact with the zeolite at 20-100 deg.C. A releasing agent is preferably a 6-9C aromatic hydrocarbon.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for separating or recovering benzothiophene and naphthalene from a mixture containing benzothiophene and naphthalene by an adsorption separation method.

[0002]

2. Description of the Related Art Benzothiophene is a substance useful as a raw material for synthesis of pharmaceuticals, agricultural chemicals and the like. This benzothiophene is contained in fractions derived from high-temperature pyrolysis of coal and petroleum, for example, coal tar fractions, fluidized catalytic cracking oils, etc. Exists. Naphthalene is also a useful substance, but there are many uses where it is not desired that a sulfur compound is present as an impurity.

However, benzothiophene (boiling point:
218 ° C.) and naphthalene (boiling point: 221 ° C.) are close to each other in boiling point, so that it is difficult to separate or recover each from a mixture by a distillation method which is a general-purpose separation technique. In addition, since benzothiophene and naphthalene form a eutectic, it is similarly difficult to employ a crystallization method which is an industrial separation technique.

Further, as a method of separating benzothiophene by adsorption separation, a method using polyethylene glycol-supported alumina as an adsorbent (German Patent 72)
-2263992) or a method using palladium chloride-supported silica gel (Fuel, 1986, 65, p270)
However, the supported metal is desorbed and eluted during the separation operation, the separation efficiency is low, and the industrial utility is low.

[0005]

An object of the present invention is to provide such a mixture comprising benzothiophene and naphthalene,
An object of the present invention is to provide an industrial method for efficiently separating or recovering both components.

[0006]

That is, the present invention relates to a method for adsorbing and separating both components from a mixture containing benzothiophene and naphthalene, wherein the adsorbent is a faujasite-type zeolite, particularly lithium or a compound of the periodic table.
A method for separating or recovering benzothiophene and naphthalene, characterized by using a faujasite-type zeolite ion-exchanged with a metal belonging to Group IIa.

Hereinafter, the present invention will be described in detail. 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 (wherein M represents a cation and n represents its valence) The faujasite-type zeolites of the above formula include X-type and Y-type, and X-type has x = 2 to 3, Type Y is represented by x = 3 to 6, and y varies depending on the degree of hydration. Among these faujasite-type zeolites, Y-type faujasite-type zeolite is a preferred adsorbent.

The faujasite-type zeolite used in the present invention may be of the hydrogen ion or ammonium ion type, but is preferably replaced with one or more metal ions. The amount of metal ion substitution is not limited, and part or all of the cations may be substituted. It is preferably at least 10%.

The metal ions to be substituted include, for example,
Periodic table Ia group such as lithium, sodium, potassium, rubidium, cesium, etc .; periodic table IIa group such as magnesium, calcium, strontium, barium; periodic table IIb group such as zinc; periodic table Ib such as copper, silver, etc. And ions of one or more metals selected from the group consisting of Group VIII of the periodic table such as iron, cobalt and nickel, and rare earth elements such as yttrium, lanthanum and cerium.

Of these metal ions, preferably, group Ia of the periodic table such as lithium, potassium and sodium; group IIa of the periodic table such as magnesium, calcium, strontium and barium; group IIb of zinc and the like; , Cobalt, nickel and the like belonging to Group VIII of the periodic table.

In terms of life as an adsorbent, lithium,
Or magnesium, calcium, strontium,
Preference is given to ions of metals belonging to group IIa of the periodic table, such as barium.

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 ion exchange amount varies depending on the type of ions, 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 faujasite type zeolite used in the present invention is appropriately selected depending on the method of contacting the object to be separated with the zeolite, and may be a compression molded product, a molded product by spray drying or the like, or a powder. Good.

For carrying out the method of the present invention, it is preferable to use a releasing agent, and as the releasing agent used for this purpose, a conventionally known releasing agent can be used. Examples of such a releasing agent include ethers such as diethyl ether, isopropyl ether, n-propyl ether, anisole, ethyl acetate, n-propyl acetate, and n-acetate.
Esters such as butyl, isopropyl acetate and isobutyl acetate, ketones such as acetone, methyl ethyl ketone, n-propyl ketone and cyclohexanone, and alcohols such as methanol, ethanol, n-propyl alcohol, isopropyl alcohol and n-butanol, Pyridine, 2-methylpyridine, 3-methylpyridine, 4
-Methylpyridine, 2,5-dimethylpyridine, 2,6
Pyridines such as dimethylpyridine, acetonitrile, aliphatic hydrocarbons such as isooctane, decane, decalin, benzene, toluene, xylene, ethylbenzene, diethylbenzene, isopropylbenzene, 1-methylnaphthalene, 2-methylnaphthalene, tetralin ,
Aromatic hydrocarbons such as decalin, ethyl biphenyl, diethyl biphenyl and the like can be mentioned.

Among these releasing agents, preferred are aliphatic hydrocarbons or aromatic hydrocarbons, and more preferred are aromatic hydrocarbons having 6 to 9 carbon atoms such as benzene, toluene, xylene, ethylbenzene and isopropylbenzene. It is a hydrocarbon.

The mixture containing benzothiophene and naphthalene as raw materials includes coal tar, coal liquefied oil,
Boiling point obtained by distilling coal gasification distillate etc. is 215 to
A fraction containing components in the 225 ° C. range can be mentioned. Further, this may be further subjected to distillation or crystallization to increase the concentration, or may be obtained by another method. When benzothiophene or naphthalene is collected or purified, the concentration of the target substance is preferably increased. It is preferable that acidic components such as phenols and heavy components such as pitch be removed in advance.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION To adsorb and separate benzothiophene and naphthalene by 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 method is continuous may be used.

In the continuous adsorption / separation method using a simulated moving bed, a plurality of adsorption towers are installed, and each operation of adsorption, concentration, and desorption is performed in each column. Is an industrial process in which

First, a mixture containing benzothiophene and naphthalene or a feedstock diluted with a diluent as required is brought into contact with a faujasite type zeolite adsorbent to selectively adsorb strongly adsorbed components. The weakly adsorbed component is separated as a 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). Furthermore, the strongly adsorbed component adsorbed is desorbed from the adsorbent by the desorbing agent,
The extract is collected together with the desorbing agent (desorption operation).

The adsorption / separation operation of the present invention can be carried out in either the gas phase or the liquid phase. However, it is preferable to carry out the adsorption / separation operation in the liquid phase because lowering the temperature can suppress side reactions. As operating conditions, the temperature is from room temperature to 200 ° C., preferably 5 ° C.
The pressure is preferably from 0 to 150 ° C. and the pressure is from atmospheric pressure to 5 MPa.

The present invention can be applied to the recovery or purification of either benzothiophene or naphthalene, or to the separation, recovery or purification of both.

[0022]

The present invention will be described more specifically with reference to the following examples and experimental examples.

In the following Experimental Examples 1 to 11, the adsorption characteristics are represented by a separation coefficient α in the following equation (1).

(Equation 1) In each experimental example, α is calculated using naphthalene as the A component and benzothiophene as the B component. Also, the amounts of each component are based on weight. In equation (1), if α is 1.0, there is no selective adsorption between the A and B components. If α is larger than 1.0, the component A is selectively adsorbed.
If it is smaller than 0, the B component is selectively adsorbed. Therefore, it can be seen that as α is larger than 1.0 or smaller than 1.0, the adsorption separation of the component A and the component B becomes easier.

Experimental Example 1 A commercially available Na-substituted Y-type faujasite type zeolite (silica / alumina ratio: 5.5) was calcined at 350 ° C. for 3 hours and cooled in a desiccator. 10 g of this adsorbent and 50.1 g of the following liquid phase mixture were charged into a flask and heated at 50 ° C.
For 3 hours to make sufficient contact. The composition ratio of the charged liquid phase mixture is naphthalene: benzothiophene: n-
Pentadecane: isooctane = 2: 2: 46: 0.1
(Weight ratio). Next, the liquid phase mixture after contact with the adsorbent was analyzed by gas chromatography, and α was determined from the composition ratio. Isooctane was added as an internal standard substance for gas chromatography analysis. The results are shown in Table 1 (metal ion substitution rate is%, the same applies hereinafter).

Experimental Example 2 A commercial K-substituted Y-type faujasite-type zeolite (silica / alumina ratio: 5.7) was used as an adsorbent in place of the Na-substituted Y-type faujasite-type zeolite of Experimental Example 1. An experiment was performed in the same manner as in Experimental Example 1. Table 1 shows the results.

Experimental Examples 3 to 7 The Na-substituted Y-type faujasite type zeolite of Experimental Example 1 was immersed in a 2N aqueous solution of a nitrate or hydrochloride of a metal ion to be exchanged at 95 ° C. for 3 hours. After repeating this operation twice, it was washed with water and dried at 120 ° C. Before use, it was calcined at 350 ° C. for 3 hours and cooled in a desiccator.
Thus, the M (Na) Y-type zeolite was prepared by partially substituting the metal ions (M _{n +} ) to be exchanged by the ion exchange method. Using this as an adsorbent, an experiment was conducted in the same manner as in Experimental Example 1. Table 1 shows the results.

Experimental Example 8 In place of the Na-substituted Y-type faujasite-type zeolite of Experimental Example 1, a commercially available HY-type faujasite-type zeolite (silica / alumina ratio: 5.6) was used as an adsorbent. The experiment was performed as in Example 1. Table 1 shows the results.

EXPERIMENTAL EXAMPLE 9 Instead of the Na-substituted Y-type faujasite-type zeolite of Experimental Example 1, a commercially available Na-substituted X-type faujasite-type zeolite (silica / alumina ratio: 2.5) was used as an adsorbent. An experiment was performed in the same manner as in Experimental Example 1. Table 1 shows the results.

Experimental Examples 10 to 11 Instead of the Na-substituted Y-type faujasite-type zeolite of Experimental Example 1, commercially available A-type zeolite (4A, powder) and N
An experiment was carried out in the same manner as in Experimental Example 1 using an a-substituted mordenite type zeolite (powder) as an adsorbent. Table 1 shows the results
Shown in In Experimental Example 11 in Table 1, the type M represents a mordenite type.

[0030]

[Table 1]

From the comparison between Experimental Examples Nos. 1 to 9 and 10 to 11, it can be seen that the faujasite type zeolite generally has a large adsorption capacity and a high separation coefficient.

Example 1 Naphthalene recovered from coal tar was separated and recovered into benzothiophene and naphthalene using the adsorbent of the present invention as a feedstock. The composition of the naphthalene recovered residue oil as the feedstock was 78.5% by weight of naphthalene, 18.9% by weight of benzothiophene, and 2.6% by weight of others. According to the same method as in Experimental Example 4, Ni (Na) Y-type zeolite (0.4 mmφ molded product) was prepared. 17 g of this zeolite was packed in a steel tube having a tube inner diameter of 8 mm and a length of 500 mm to form an adsorption column. The column was maintained at a temperature of 80 ° C., and para-xylene was supplied as a developing agent at a rate of 2.5 ml / min to fill the column with para-xylene. Then, a 25 wt% paraxylene solution of the feedstock (1,3,5-triisopropylbenzene 2 as an internal standard substance)
5% by weight) was supplied to the column. Subsequently, para-xylene was supplied at a rate of 2.5 ml / min for 20 minutes, and the effluent was collected every 0.3 minutes and analyzed by gas chromatography. The result is shown in FIG. In FIG. 1, the horizontal axis represents the outflow time (minutes), and the vertical axis represents the normalized concentration of each component. According to FIG. 1, it can be seen that benzothiophene and naphthalene are completely separated. In addition, the outflow time 12-18
A minute sample was collected, para-xylene was distilled off, and dry weight measurement and component analysis were performed. As a result, the outflow time 12 ~
The 18 minute sample was found to have 93% benzothiophene by weight and a 99% recovery.

The feedstock used in the following Examples 2 to 10 and Experimental Example 12 is a residual oil by-produced when producing purified naphthalene by crystallization after acid extraction and distillation of coal tar (hereinafter referred to as feedstock). ), And the composition (% by weight) was as follows. Naphthalene 93.0% Benzothiophene 6.0% 1-methylnaphthalene 0.1% 2-methylnaphthalene 0.1% Quinoline 0.1% Others 0.7%

Example 2 A commercially available Na-substituted Y-type faujasite-type zeolite (silica / alumina ratio: 5.5, 0.4 mmφ molded product) was partially exchanged with calcium ions by an ion exchange method,
An a (Na) Y type zeolite was prepared. This was calcined at 350 ° C. for 4 hours as an adsorbent, and cooled with a desiccator. 20 g of this adsorbent was used for a tube with an inner diameter of 8 mm and a length of 500 mm.
Was packed into a steel cylindrical tube of No. 1 to obtain an adsorption column. The column temperature was maintained at 80 ° C, and toluene was added to the column as a desorbing agent.
The mixture was supplied at a rate of ml / min, and the column was filled with toluene. Then, feed materials (1, 3, 5 as internal standard substances)
1.25% triisopropylbenzene).
ml, followed by toluene at a rate of 5 ml / min.
Minutes. At this time, the effluent was collected every 36 seconds and analyzed by gas chromatography. The result is shown in FIG. In FIG. 2, the horizontal axis represents the outflow time (minutes), and the vertical axis represents the normalized concentration of each component. According to FIG. 2, it is clear that benzothiophene and naphthalene are completely separated. From this experimental result, the partition coefficient was determined by a conventional method using 1,3,5-triisopropylbenzene as a standard substance. The results are shown in Table 2 (metal ion substitution rate is%, the same applies hereinafter). In addition, 600 ml of the feed material, which corresponds to the load amount of 480 times of this test (hereinafter referred to as pulse test), was circulated in 2 hours, and after the adsorbent was deteriorated, the pulse test was performed again, and the distribution coefficient was obtained from the result. Was. Table 2 shows the results
Shown in It can be seen that the separation performance hardly changed before and after the load test.

Example 3 A commercially available Na-substituted Y-type faujasite-type zeolite was partially exchanged with strontium ions by an ion exchange method to prepare a Sr (Na) Y-type zeolite. Using this as an adsorbent, a test was conducted in the same manner as in Example 2. Table 2 shows the results.

Example 4 A commercially available Na-substituted Y-type faujasite-type zeolite was partially exchanged with magnesium ions by an ion exchange method.
Mg (Na) Y type zeolite was prepared. Using this as an adsorbent, a test was conducted in the same manner as in Example 2. Table 2 shows the results.

Example 5 A commercially available Na-substituted Y-type faujasite-type zeolite was partially exchanged with barium ions by an ion exchange method to obtain Ba.
(Na) Y-type zeolite was prepared. Using this as an adsorbent, a test was conducted in the same manner as in Example 2. Table 2 shows the results
Shown in

Examples 6 to 9 Instead of toluene, benzene, p-xylene, ethylbenzene or isopropylbenzene (IP
The test was carried out in the same manner as in Example 2 using B). Table 2 shows the results.

Example 10 A commercially available Na-substituted Y-type faujasite-type zeolite was partially exchanged with lithium ions by an ion exchange method to obtain Li
(Na) Y-type zeolite was prepared. Using this as an adsorbent, a test was conducted in the same manner as in Example 2. Table 2 shows the results
Shown in

Experimental Example 12 A commercially available Na-substituted Y-type faujasite-type zeolite was partially exchanged with copper ions by an ion exchange method to obtain Cu (N
a) Y-type zeolite was prepared. Using this as an adsorbent, a test was conducted in the same manner as in Example 2. Table 2 shows the results. According to this, it is recognized that the separation performance is reduced before and after the load test.

[0041]

[Table 2]

[0042]

According to the separation and recovery method of the present invention, both components can be efficiently separated from a mixture containing benzothiophene and naphthalene by a simple adsorption method.
It is useful as a method for recovering or purifying benzothiophene and / or naphthalene.

[Brief description of the drawings]

FIG. 1 is a view showing the relationship between the normalized concentration of each component in an effluent and the effluent time in Example 1.

FIG. 2 is a diagram showing the relationship between the normalized concentration of each component in the effluent and the outflow time in Example 2.

Claims (4)

[Claims] 1. A method for adsorbing and separating both components from a mixture containing benzothiophene and naphthalene,
A method for separating benzothiophene and naphthalene, characterized by using lithium or a faujasite-type zeolite ion-exchanged with a metal belonging to Group IIa of the periodic table as an adsorbent. 2. A mixture containing benzothiophene and naphthalene is admixed with lithium or II of the periodic table as an adsorbent.
A method for recovering benzothiophene and / or naphthalene, comprising performing adsorption separation using a faujasite-type zeolite ion-exchanged with a metal belonging to group a. 3. A mixture containing benzothiophene and naphthalene, wherein lithium or lithium of the periodic table is used as an adsorbent.
A method for purifying naphthalene, comprising performing adsorption separation using faujasite-type zeolite ion-exchanged with a metal belonging to group a. 4. The method for separating and recovering benzothiophene and naphthalene according to claim 1, wherein an aromatic hydrocarbon having 6 to 9 carbon atoms is used as the desorbing agent.