JPS63243043A - Production of 2,6-methylisopropylnaphthalene - Google Patents

Abstract

PURPOSE:To obtain the titled compound in high yield, industrially and advantageously, by carrying out isopropylation process from methylnaphthalene and propylene, distillation process and two-stage adsorption and separation using zeolite adsorbents showing specific selective adsorptivity, respectively. CONSTITUTION:Methylnaphthalene 27 is isopropylated 21 with propylene 28, the reaction product 30 is distilled 23 and 24 to give methylmonoisopropyl naphthalene fraction 34. Then 2,6-isomer and 2,7-isomers are selectively adsorbed and separated 25 from the fraction 34 by the use of a first zeolite adsorbent showing selective adsorptivity to both 2,6-isomer and 2,7-isomer in the fraction 34 and then 2,7-isomer 37 is selectively adsorbed and removed 35 by the use of a second zeolite adsorbent showing strong adsorptivity to 2,7-isomer than 2,6-isomer to continuously obtain 2,6-methylisopropylnaphthalene 36 useful for producing 2,6-naphthalenedicarboxylic acid (polyester raw material) from the raw materials in high yield.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an industrially advantageous method for producing 2,6-methylisopropylnaphthalene.

[Prior art]

Conventionally, in order to obtain polyester, terephthalic acid, 2,
It is widely known that 6-naphthalene dicarboxylic acid is subjected to a polymerization reaction with glycol. Polyester obtained from 2,6-naphthalene dicarboxylic acid has superior physical properties such as heat resistance compared to those obtained from terephthalic acid, so 2,6-dinaphthalene is industrially advantageous as a raw material for polyester. It is desired to establish a manufacturing method.

Conventionally, as a method for industrially producing 2,6-naphthalene dicarboxylic acid, a method of using 2,6-dimethylnaphthalene as a raw material and oxidizing it has been considered as a general method. In the case of this method, an important technique is how to obtain 2°6-dimethylnaphthalene, which is a raw material for 2,6-naphthalene dicarboxylic acid, at low cost and with high purity.

2.6-Dimethylnaphthalene is contained in the dimethylnaphthalene fraction obtained by distillation of petroleum or coal tar. This dimethylnaphthalene fraction contains many substances whose boiling points are very close to each other, such as ethylnaphthalene, biphenyl, and acenaphthene.
In addition to 6-dimethylnaphthalene, it includes isomers such as 2,7-dimethylnaphthalene and 2,3-dimethylnaphthalene.

Therefore, from such other types of compounds and isomer mixtures, 2,
Selective separation of 6-dimethylnaphthalene presents significant difficulties. In particular, since the boiling points of the 2,6-isomer and the 2,7-isomer are extremely similar, it is extremely difficult to separate the two, and it is virtually impossible to separate the two by distillation. It is possible.

Conventionally, an adsorption separation method using a zeolite adsorbent has been proposed as an industrially advantageous method for separating isomers containing 2,6-dimethylnaphthalene and 2,7-dimethylnaphthalene (Tokuko Sho et al. 49-27578
(Japanese Patent Publication No. 52-945). However, in this adsorption separation method, the 2゜7-isomer is adsorbed to the adsorbent with higher selectivity than the 2.6-isomer, so this method is not suitable for high-purity separation of the 2,7-isomer. Although this method is excellent, it is unsatisfactory as a method for high-purity separation of 2,6-isomers. In order to adsorb and separate the 2,6-isomer with high purity, it is necessary to develop an adsorbent that adsorbs the 2,6-isomer with higher selectivity than the 2,7-isomer. No satisfactory adsorbent has yet been proposed.

〔the purpose〕

The present invention provides 2,6-dimethylnaphthalene as a raw material.
, 6-naphthalene dicarboxylic acid production process.

〔composition〕

According to the present invention, an isopropylation reaction step of isopropylating methylnaphthalene with propylene, a distillation step of separating a methylmonoisopropylnaphthalene fraction from the isopropylated product, and a 2,6- It consists of an adsorption separation step for separating methylisopropylnaphthalene, and the adsorption separation step separates the methylmonoisopropylnaphthalene fraction into 2,
6-methylisopropylnaphthalene and 2,7-methylisopropylnaphthalene contained in the fraction are contacted with a first zeolide adsorbent that selectively adsorbs both 2,7-methylisopropylnaphthalene and 2,7-methylisopropylnaphthalene.
-Methylisopropylnaphthalene and 2,7-methylisopropylnaphthalene with higher selectivity than other isomers
The first step is adsorption to an adsorbent and then desorption by a desorbent, and the desorbed product obtained in the first step exhibits stronger adsorption to 2,7-methylisopropylnaphthalene than to 2,6-methylisopropylnaphthalene. After contacting with a second zeolite adsorbent and adsorbing 2,7-methylisopropylnaphthalene contained in the desorbed product to the second adsorbent with a higher selectivity than 2,6-methylisopropylnaphthalene, the desorbent 2, characterized in that it consists of a second stage of desorption and removal;
A method for producing 6-methylisopropylnaphthalene is provided.

Next, the present invention will be explained in detail.

[Methylnaphthalene isopropylation step] This step is a step in which methylnaphthalene is reacted with propylene in the presence of a catalyst to obtain an isopropylated product. Methylnaphthalene, which is a raw material for isopropylation, may be of any type produced from petroleum oil, coal oil, or the like. However, if the isopropylation catalyst contains components that may poison the catalyst, such as sulfur compounds or nitrogen compounds, these can be removed using well-known refining techniques, hydrorefining, activated clay treatment, etc. It is preferable to remove these compounds. The isopropylation reaction is a conventionally well-known reaction, and is carried out as a liquid phase or gas phase reaction according to a conventionally known method. Catalysts include silica/alumina, crystalline aluminosilicate, nickel oxide/silica, silver oxide/silica alumina, silica/magnesia,
Solid acid catalysts such as alumina boria and solid phosphoric acid, and free delta rough catalysts such as aluminum chloride, hydrogen fluoride and phosphoric acid are used. In this isopropylene ring, the isopropyl group attached to the naphthalene ring is easily rearranged to another naphthalene ring by a transalkylation reaction in the presence of the alkylation catalyst as described above. Therefore, this isopropylation reaction is considered to be a reversible reaction, and an equilibrium composition exists between methylnaphthalene and methylmonoisopropylnaphthalenes. The production rate of methylmonoisopropylnaphthalene depends on the ratio of methylnaphthalene and propylene in the reaction, temperature, type and amount of catalyst, etc.

When performing the isopropylation reaction using a Friedel-Crafts catalyst, the reaction is carried out at room temperature to 150°C, preferably at 50°C to
A temperature of 100°C, a pressure of normal pressure to 10 atm, and a catalyst to raw material ratio of 0.05 to 1.0, preferably 0.08 to 0.
It is carried out under 5 conditions. In order to increase the yield of methylmonoisopropylnaphthalene, the molar ratio of isopropyl groups to naphthalene nuclei in the alkylated product should be between 0.2 and 2.
．． 0. Preferably it is set to 0.3 to 1.0. When using a solid acid catalyst, the reaction temperature is 150 to 500°C,
Pressure 0-50kg/a#G, contact time 0.02-6. O
hr, preferably at a temperature of 200 to 350°C,
Pressure 0-35kg/dG, contact time 0.4-2.5hr
range. If the temperature is high or the contact time is long,
A decomposition reaction occurs and by-products are produced. Furthermore, when the temperature is low or the contact time is short, the yield of methylmonoisopropylnaphthalene decreases. In this isopropylation reaction step, an isopropylation product containing unreacted methylnaphthalene, methylmonoisopropylnaphthalene, methylisopropylnaphthalene and more methylpolyisopropylnaphthalene is obtained, and the proportion of methylmonoisopropylnaphthalene therein is: Usually 10-60
ft%.

In addition, when carrying out this isopropylation reaction step, a low boiling point fraction consisting of methylnaphthalene obtained in the subsequent distillation separation step of the isopropylation reaction product and a high boiling point fraction consisting of methylpolyisopropylnaphthalene of methyldiisopropylnaphthalene or higher are also used. Preferably, a portion of the isopropylation reaction is recycled to the isopropylation reaction step. When performing an isopropylation reaction by circulating such a fraction, an isopropylation reaction occurs due to the reaction between unreacted methylnaphthalene and propylene that constitute the recycled low-boiling fraction, resulting in methylmonoisopropylnaphthalene. In addition to the methylpoisopropylnaphthalene constituting the high-boiling fraction, a transalkylation reaction occurs between the methylpolyisopropylnaphthalene and methylnaphthalene to produce methylmonoisopropylnaphthalene, and the supplied methyl The yield of methylmonoisopropylnaphthalene per naphthalene is increased.

[Adsorption separation process of methyl monoisopropyl naphthalene fraction]

This step is a step in which 2,6-methylisopropylnaphthalene is separated and recovered with high purity from the methylmonoisopropylnaphthalene fraction obtained from the distillation step by a two-stage adsorption separation step. In this case, since the polar substances contained in the methyl monoisopropylnaphthalene fraction are more strongly adsorbed by the adsorbent than methylisopropylnaphthalene, it is preferable to remove them in advance.

This polar substance is produced by partial oxidation of aromatic hydrocarbons such as methylnaphthalene and methylisopropylnaphthalene, and is composed of aldehydes, ketones, alcohols, phenols, etc. It can be removed using zeolite or type 1 zeolite.

In the first adsorption separation step, the methyl monoisopropylnaphthalene fraction is brought into contact with a first zeolite adsorbent that selectively adsorbs both 2,6-methylisopropylnaphthalene and 2,7-methylisopropylnaphthalene.

Through this adsorption treatment, 2,6-methylisopropylnaphthalene and 2,7
- Methylisopropylnaphthalene is adsorbed with higher selectivity than other isomers as weakly adsorbed components. Next, this adsorbate is desorbed using a desorbent to obtain a mixture of 2,6-methylisopropylnaphthalene and 2,7-methylisopropylnaphthalene as a desorbent. The first zeolite adsorbent used in this first stage adsorption separation process has selective adsorption properties for both 2,6-isomer and 2,7-isomer as strongly adsorbed components among methyl monoisopropyl naphthalene isomers. It suffices as long as it shows. Such adsorbents include metal ions selected from alkali metals or alkaline earth metals, such as potassium, lithium, rubidium, cesium, barium, calcium, magnesium, strontium, lanthanide and lanthanide metals. An X-type or Y-type zeolite substituted with one or more metal ions selected from among them is used. Moreover, such a zeolite adsorbent can also contain other metal ions such as lead, iridium, yttrium, and zirconium in addition to the metal ions mentioned above.

In addition, in the second stage adsorption separation process, the mixture of 2,6-methylisopropylnaphthalene and 2,7-methylisopropylnaphthalene obtained as a desorbed product in the first stage adsorption separation process is It is brought into contact with a second zeolite adsorbent that exhibits stronger adsorption properties for 2,7-methylisopropylnaphthalene than for isopropylnaphthalene. Through this adsorption treatment, 2,7-methylisopropylnaphthalene as a strongly adsorbed component is adsorbed on the adsorbent with higher selectivity than 2,6-methylisopropylnaphthalene as a weakly adsorbed component. Next, this adsorbed material is desorbed using a desorbent. In this way, 2,6-methylisopropylnaphthalene and 2,7-methylisopropylnaphthalene can be separated from each other with high purity. The second zeolite adsorbent is 2.6-methylisopropylnaphthalene.
, 7-methylisopropylnaphthalene may be used. Such adsorbents include metal ions selected from alkali metals or alkaline earth metals other than sodium, preferably potassium ions and/or
Alternatively, there is Y-type zeolite substituted with barium ions. In addition to the metal ions mentioned above, this zeolite adsorbent also contains
Other metal ions such as lead, iridium, yttrium, and zirconium may also be included.

The particle size of the zeolite adsorbent is approximately 3 to 300 mesh, and may be appropriately selected depending on the type of adsorption bed. Furthermore, it is also possible to improve the adsorption selectivity of the zeolite adsorbent by adjusting its water content. The water present in the zeolite is partially contained at the cation or base exchange sites or is contained within the cavities of the adsorbent. 100
It is desirable that the moisture content, measured by weight loss under ignition at 0° C., is in the range of 5 to 20 Ilt%, based on the weight of the adsorbent. Moisture content can be adjusted by adding an appropriate amount of water to the raw material mixture.

When performing adsorption separation using a zeolite adsorbent, the conditions for the adsorption/desorption step are a temperature of 50 to 300°C, preferably 80 to 200°C.
00°C and a pressure of 1 to 20 atm, preferably 5 to 15 atm.

The desorbent used in the desorption step may be a substance that is quickly adsorbed to the adsorbent and has the ability to desorb the already adsorbed substance. If the adsorption force is weak, a large amount of desorbent is required to desorb the product, the concentration of the desorbent in the product increases, and the cost required to separate the desorbent increases. On the other hand, if the adsorption power of the desorbent is too strong, the adsorption capacity of the product decreases as the desorbent is not sufficiently desorbed from the adsorbent during adsorption of the product, and the cost required for separation in the product when recovering the product. increases. Therefore, a substance with appropriate adsorption power is selected as the desorbent. Furthermore, when considering the separation of the product and raffinate by distillation, it is desirable that the boiling point difference between the product and raffinate-1 is at least 10°C, preferably at least 20°C. As such skin care agents, aromatic hydrocarbons, alkyl aromatic hydrocarbons, hydrides thereof, paraffins, etc. are usually used.

The adsorption separation according to the invention may be carried out in fixed bed, fluidized bed, moving bed, preferably simulated moving bed mode. Adsorption separation using a simulated moving bed method is an established technology.
It is applied to adsorption separation of xylene isomer mixtures, for example, Japanese Patent Publication No. 1.5681/1983
It is described in Publication No. 10547 and the like.

As mentioned above, in the two-stage adsorption separation method of the present invention, the target 2,6-methylisopropylnaphthalene can be separated and recovered with high purity from other components that have similar boiling points and are most difficult to separate from each other. Can be done. According to the adsorption separation technique using the above-mentioned simulated moving bed method, 2,6-methylisopropylnaphthalene can be separated and recovered with a high purity of 99% by weight or more.

To explain in more detail the adsorption separation using the simulated moving bed system, this adsorption separation technique is carried out by continuously cycling the following basic operations: adsorption operation, concentration operation, desorption operation, and desorbent recovery operation.

(1) Adsorption operation: The raw material to be treated is brought into contact with the zeolite adsorbent, and the target component to be adsorbed as a strongly adsorbed component is selectively adsorbed, and other components that are weakly adsorbed are recovered together with the desorbent as a raffinate stream. Ru.

(2) Concentration operation: The adsorbent that has selectively adsorbed the target component is brought into contact with a portion of the extract, which will be described later.
Weakly adsorbed components remaining on the adsorbent are expelled and strongly adsorbed components are concentrated.

(3) Desorption operation 2'a The adsorbent containing the condensed strongly adsorbed components is brought into contact with a desorbent, the strongly adsorbed components are expelled from the adsorbent, and the adsorbent is recovered together with the desorbent as an extract stream.

(4) Desorbent recovery operation: The adsorbent that has substantially adsorbed only the desorbent comes into contact with a portion of the raffinate stream, and a portion of the desorbent contained in the adsorbent is recovered as a desorbent recovery stream.

FIG. 1 shows a schematic diagram of an adsorption separation operation using a simulated moving bed. In this figure, numerals 1 to 12 are adsorption chambers containing zeolite adsorbents, which are interconnected. , 13 is a desorption agent supply line, 14 is an extract extraction line, 16
17 indicates the raffinate extraction line, and 17 indicates the recycling line. Adsorption chambers I to 12 and each line 13 shown in the drawing
In the arrangement states 1 to 16, a desorption operation is performed in adsorption chambers 1 to 3, a concentration operation is performed in adsorption chambers 4 to 6, an adsorption operation is performed in adsorption chambers 7 to 10, and a desorbent recovery operation is performed in adsorption chambers 11 to 12. .

In such a simulated moving bed, each supply and withdrawal line is moved by one adsorption chamber in the liquid flow direction at regular time intervals by valve operation. Therefore, in the next arrangement of adsorption chambers, adsorption chambers 2 to 4 perform desorption operations, adsorption chamber 5
Concentration operation in ~7, adsorption operation in adsorption chambers 8 to i1, adsorption chamber 1
The desorbent recovery operation is performed in steps 2 to 1, respectively. By sequentially performing such operations, adsorption separation treatment using a simulated moving bed is achieved. In addition, although the number of adsorption chambers is specified as 12 in FIG. 1, it should be noted that the number of adsorption chambers is not limited.

In the present invention, in order to efficiently perform adsorption separation treatment using a simulated moving bed, the flow rate of each operation zone is an important operating variable.If the raw material supply scene is F, the following is calculated based on the volume per unit time. It is preferable to set it as follows.

(↑) Adsorption operation band flow rate: 0.2F+E-5<L
,, <3.5F+E-3 (2) Concentration operation zone flow rate L2
:0.2F+E-5<L, <3.5F+E-5(3)
Desorption operation band flow rate L3: 0.5F+E-5<L3 (4)
Desorbent recovery operation zone flow rate L4: L, <0.5F+E-5
However, in the above formula, E represents the porosity of the adsorbent layer, and S represents the pseudo migration speed of the adsorbent.

In the adsorption operation zone, it is desirable to adsorb strongly adsorbed components and to avoid adsorbing weakly adsorbed components as much as possible. In addition, in the concentration operation zone, it is necessary to desorb weakly adsorbed components as much as possible and concentrate strongly adsorbed components into the adsorbent. Therefore, the flow rates of these two operation zones must be set within an appropriate flow rate range depending on the adsorption characteristics of the components to be separated from each other.

Next, in the desorption operation zone, it is necessary to completely desorb the strongly adsorbed components, and it is desirable to keep the flow rate as large as possible in consideration of the flow rate balance with other operation zones. In addition, in the desorbent recovery operation zone, in order to reduce the concentration of adsorbent components (methyl mole isopropyl naphthalene isomer) in the desorbent recycled from the outlet of this zone to zero, the flow rate is kept as low as possible to completely remove the adsorbent components. It is necessary to adsorb it to an adsorbent. Taking these into consideration, it is preferable to set the flow rate of each operation zone as described above.

In addition, in the two-stage adsorption separation process of the present invention, the 2,6-isomer obtained from the first-stage separation process and the 2,7-isomer
- When a mixture containing isomers is injected into the second stage separation step, the desorbent contained in the mixture may or may not be removed by an operation such as distillation separation.

[Methyl monoisopropyl naphthalene isomerization process]

This step is a step in which the 2.6-isomer obtained in the adsorption separation step is separated and the other isomer mixture is isomerized to obtain an isomer mixture containing the 2,6-isomer. . This isomerization step can be performed using a solid acid or a Friedel-Crafts catalyst similarly to the isopropylation step. This isomerization step yields an isomer mixture of methylisopropylnaphthalene, including the 2,6-isomer. This mixture is recycled to the adsorption separation step.

This isomerization step can be performed separately from the isopropylation step, or can be performed simultaneously with the isopropylation step.

Next, the present invention will be explained in detail with reference to FIG.

In FIG. 2, 21 is an isopropylation reactor, 22 is a catalyst separator, 23 and 24 are distillation columns, and 25 is an adsorption separation device 26 is an isomerization reactor.

Raw materials methylnaphthalene and propylene are introduced into the isopropylation reactor 21 through lines 27 and 28, respectively, and Friedel-Crafts catalyst (aluminum chloride) is introduced through line 29. Also, in this reactor, a low boiling point fraction consisting of methylnaphthalene from the distillation column 23 and a high boiling point fraction consisting of methylpolyisopropylnaphthalene of methyldiisopropylnaphthalene or higher from the distillation column 24 are sent to lines 38 and 3, respectively.
5. In this case, the reactor 21 is normally maintained at a temperature of 70 to 100°C and a pressure of 1 atmosphere.

The isopropylation product obtained in the isopropylation reactor 21 is introduced through line 30 to the catalyst separator 22, where the Friedel-Crafts catalyst is separated. A portion of the separated catalyst passes through line 32 to isomerization reactor 26
The remainder is recycled to the isopropylation reactor 21 through line 31. The isopropylation product after separation of the catalyst is sent to distillation column 23.24;
A low-boiling fraction consisting of methylnaphthalene is separated, which is recycled to the isopropylation reactor 21 through a line 38, and a high-boiling fraction consisting of methylpolyisopropylnaphthalene, which is higher than the methyldiisopropylnaphthalene separated in the distillation column 24. The fraction is recycled to the isopropylation reactor 21 through line 35. The methyl monoisopropyl naphthalene fraction separated in the distillation column 24 is sent to the adsorption separation device 25 through a line 34.

The adsorption separation device 25 continuously adsorbs and separates the methyl monoisopropyl naphthalene fraction by a chromatographic separation method using a zeolite adsorbent, and is usually an adsorption separation device using a pseudo-transfer system. The adsorption separation device 25 also includes a distillation device for recovering and reusing the desorbent. When the adsorption separation of the present invention is carried out in a simulated moving bed, the second stage adsorption tower produces an extract consisting of a desorbent and 2,7-methylisopropylnaphthalene, and an extract consisting of a desorbent and 2,6-methylisopropylnaphthalene. A raffinate consisting of is obtained. The desorbent contained in these extracts and raffinate is separated by distillation and recycled to the adsorption tower as a desorbent.

The 2,6-methylisopropylnaphthalene obtained as described above is recovered as a product through line 36,
In addition, 2,7-line propylnaphthalene is line 37
is sent to the isomerization reactor 2G.

In the isomerization reactor 26, an isomerization reaction of 2,7-methylisopropylnaphthalene sent from the adsorption separation device 25 is performed in the presence of the catalyst from the catalyst separator 26. The isomerized product containing 2,6-methylisopropylnaphthalene obtained by this reaction is sent to the catalyst separator 22 along with the isopropylation product from the isopropylation reaction tower 21 through a line 33.

In the manner described above, 2,6-methylisopropylnaphthalene can be obtained continuously with high purity using methylnaphthalene and propylene as raw materials.

The 2,6-methylisopropylnaphthalene thus obtained is produced by oxidizing the 2,6-methylisopropylnaphthalene.
It can be naphthalene dicarboxylic acid.

〔effect〕

According to the present invention, 2,6-methylisopropylnaphthalene can be produced continuously with high purity using methylnaphthalene and propylene as raw materials. The 2,6-methylisopropylnaphthalene obtained in the present invention is suitable as a raw material for producing 2,6-naphthalene dicarboxylic acid used as a raw material for polyester.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples.

Note that the relative separation coefficient β value shown below is 2,
When a raw material mixture containing 6-methylisopropylnaphthalene was adsorbed using a zeolite adsorbent, 2,6-
It provides an index of the relative adsorption strength of the mixed components based on methyl isopropyl naphthalene, and is expressed by the following formula.

β[:i] = K (i) / K [2,6)
(1) β[i]: Relative separation coefficient K of mixture component i (i): Solid-liquid equilibrium constant K (2, 6) of mixture component i
:Solid-liquid equilibrium constant of 2,6-methylisopropylnaphthalene Example 1 0.13 mol per 1 m0 of methylnaphthalene
0.009 per m01 of methylnaphthalene in the presence of an aluminum chloride catalyst at a reaction temperature of 50°C and normal pressure.
Blow propylene at a flow rate of mol/min, and
1n reaction was carried out. At the end of the reaction, the total number of moles of propylene blown into the reactor was 0.8 mole per 1 mol of raw material methylnaphthalene. As a result of analyzing the reaction product by gas chromatography, a product having the composition shown in Table 1 was obtained.

Further, this product was distilled to separate a methylisopropylnaphthalene fraction. Distillation was carried out at a pressure of 50 mm, 11 g, and a reflux ratio of 5, and a fraction distilled out at a top temperature of 283 to 285° C. was collected. The yield of the distillate was 32.3 wt%. Results of analyzing distillate oil by gas chromatography 1
An isomer of methylisopropylnaphthalene having the composition shown in Table 2 was obtained.

Table 1 [Isopropylation reaction results (1)] Example 2 Using the mixture of methylnaphthalene, methylmonoisopropylnaphthalene, methyldiisopropylnaphthalene, and methyltriisopropylnaphthalene shown in Table 3 as raw materials,
In the presence of an aluminum chloride catalyst at a rate of 0.21 mol per mol of raw materials, at a reaction temperature of 55°C and under normal pressure, propylene was blown at a flow rate of 0.016 mol/m j-n per 1 mol of raw materials, and 40 ml of reacted. Ta.

The results of gas chromatography analysis of the reaction product are shown in Table 3.

Example 3 Methylnaphthalene was isopropylated with propylene, and methylmonoisopropylnaphthalene was separated from the product by distillation. A methylmonoisopropylnaphthalene isomer mixture having the composition shown in Table 4 was used as a raw material, and adsorption separation was carried out. We conducted an experiment. The adsorbent used in the adsorption separation experiment consisted of seven types of zeolite shown in Table 5, Ba,
It is ion-exchanged with Ba and pb. Ion exchange was performed by the method shown below.

(Ba ion exchange) BaCQ 2 aqueous solution (
Add about 100g of 0.5mon/Q) and set the temperature to 9.
It was left to stand at 0 to 100°C for 2 hours.

After repeating the above operation three times, after drying, the temperature was 400℃.
It was baked for 3 hours.

(Ba, K ion exchange) Na-type yg zeolite approximately Log to BaC (12(0,5
mo Q/(1), KNO3(1,0mo QhaD
About 100 g of an aqueous solution was added thereto, and the mixture was left at a temperature of 90 to 100°C for 2 hours. After repeating the above operation three times, after drying,
It was baked at a temperature of 400°C for 3 hours.

(Ba, Pb ion exchange) 10w to about 20g of Y-type zeolite ion-exchanged with Ba
t% (7) Approximately 100 g of Pb (No3)z aqueous solution
The mixture was then left to stand at a temperature of 90-100°C for 5 hours. After drying the zeolite, it was calcined at a temperature of 400°C for 3 hours.

The adsorption separation experiment was carried out using the method shown below.

Approximately 4 g of adsorbent and approximately 8 g of raw oil were placed in an autoclave with an internal volume of 30 cc, and the temperature was kept constant while stirring.
I held it for 20 minutes. Adsorbent and raw material residual liquid are filtered.

was separated, and the adsorbate in the adsorbent was desorbed by Soxhlet extraction using a toluene solvent after washing the adsorbent with isooctane. The composition of the raw material residual liquid (liquid phase) and adsorbent (adsorption phase) was analyzed by gas chromatography and shown in Table 1-6.
, 7. As is clear from the results in Table 6, the four types of zeolite adsorbents shown in Table 6 are all 2,6-methylisopropylnaphthalene and 2,7-methylisopropylnaphthalene (however, regarding the adsorbent, There is almost no difference in the β value of 2,4-isomer), but the β value with other methyl monoisopropyl naphthalene isomers is about 2.
However, it is suitable as an adsorbent for use in the first stage of a two-stage adsorption separation. Also, from the results shown in Table 1-7, 1
The three types of adsorbents shown in Table 7 have β values of 2,6-methylisopropylnaphthalene and 2,7-methylisopropylnaphthalene that differ by more than twice, and the
It is suitable as an adsorbent for use in stages.

-35-Example 4 Adsorption separation of 2,6-methylisopropylnaphthalene from raw material 1 shown in Table 4 was carried out using a simulated moving bed continuous chromatography separation apparatus shown in FIG.

Separation of 2.6-methylisopropylnaphthalene was carried out in two steps as shown below.

First, in the first stage, 2,6-methylisopropylnaphthalene and 2,7-methylisopropylnaphthalene are taken out as extracts from the raw material mixture, and in the second stage, 2,6-methylisopropylnaphthalene and 2,7-methylisopropylnaphthalene are extracted as raw materials from the extract obtained in the first stage.
, 6-methylisopropylnaphthalene was separated into Raffine-1.

In the device shown in FIG. 1, in the first stage, the internal volume is 4
Adsorbent B shown in Example 3 was packed into 0 mQ adsorbent columns 1 to 12. Raw materials shown in Table 4 from line 15
1 was fed at ]OOm Q /HR, and the desorbent was fed from line 13 at ], 65 m Q /HR. line 14
Extra rough 1~], 36mQ/old (extract raffinate from line 16, 129mQ/II
Extracted with R. At this time, change column 1 to 1 at 150 second intervals.
2, 11 to 10, 7 to 6, and 4 to 3 at the same time. 2 in the extract obtained in the first stage,
The concentration of 6-methylisopropylnaphthalene was about 70wt% on a desorbent-free basis, the concentration of 2,7-methylisopropylnaphthalene was about 30tzt%, and the recovery rate of 2,6-methylisopropylnaphthalene was 98%.

Next, in the second stage, the desorbent was removed by distillation from the extract obtained in the first stage and used as a raw material. Adsorbent columns 1 to 12 were filled with adsorbent G shown in Example 3. The raw material mixture was supplied from line 15 at 100 mA/HR, and the desorbent was supplied from line 13 at 110 mQ/HR. Extract from line 14 ], ], O
The raffinate was extracted from line 16 using Loom Q /IIR. At this time, column 1 was moved to 12, 11 to 10, 7 to 6, and 4 to 3 simultaneously at 120 second intervals. The purity of 2,6-methylisopropylnaphthalene in Roughine-1 obtained in the second stage was 99 wt % on a desorbent-free basis, and the recovery rate based on the first stage raw material was 90%.

Example 5 Using the mixture of methyl monoisopropyl naphthalene shown in Table 8 as a raw material, 0°24m0Q per moff of raw material
of aluminum chloride catalyst was added, and the temperature was 60°C under normal pressure.
It was allowed to react for 0 minutes. The reaction product was distilled, a methyl monoisopropyl naphthalene fraction was collected, and then analyzed by gas chromatography. The results are shown in Table 8.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an adsorption separation operation using a simulated moving bed, and FIG. 2 does not show a flow sheet of the method of the present invention. 1 to 12... Adsorption chamber 13... Desorbent supply line 14... Extraction line 15 to extra rough 1... Raw material mixture line 16... Raffinate extraction line 17... Recycle line 18. ... Pump 21 ... Isopropylation reactor 22 ... Catalyst separator 23.24 ... Distillation column 25 ... Adsorption separation device 26 ... Isomerization reactor.

Claims (2)

[Claims] (1) An isopropylation reaction step of isopropylating methylnaphthalene with propylene, a distillation step of separating a methylmonoisopropylnaphthalene fraction from the isopropylated product, and a 2,6-methylmonoisopropyl fraction from the methylmonoisopropylnaphthalene fraction. It consists of an adsorption separation step for separating naphthalene, and the adsorption separation step includes:
The methyl monoisopropylnaphthalene fraction is brought into contact with a first zeolite adsorbent that exhibits selective adsorption properties for both 2,6-methylisopropylnaphthalene and 2,7-methylisopropylnaphthalene, and the 2,6-monoisopropylnaphthalene fraction contained in the fraction is - a first step in which methylisopropylnaphthalene and 2,7-methylisopropylnaphthalene are adsorbed on a first adsorbent with higher selectivity than other isomers and then desorbed with a desorbent; The desorbed product is brought into contact with a second zeolite adsorbent that exhibits stronger adsorption to 2,7-methylisopropylnaphthalene than to 2,6-methylisopropylnaphthalene, and the 2,7-methylisopropylnaphthalene contained in the desorbed product is removed. 2,6-Methylisopropylnaphthalene is adsorbed on the second adsorbent with a higher selectivity than 2,6-methylisopropylnaphthalene, and then the second step is desorbed and removed using a desorbent.
- A method for producing methylisopropylnaphthalene. (2) an isopropylation reaction step of isopropylating methylnaphthalene with propylene; and a low-boiling fraction consisting of methylnaphthalene from the isopropylation product;
a distillation step of separating into a methyl monoisopropyl naphthalene fraction and a high boiling point fraction consisting of methyl polyisopropyl naphthalene or higher than methyl diisopropyl naphthalene;
The methyl monoisopropylnaphthalene fraction is brought into contact with a first zeolite adsorbent that exhibits selective adsorption properties for both 2,6-methylisopropylnaphthalene and 2,7-methylisopropylnaphthalene, and the 2,6-monoisopropylnaphthalene fraction contained in the fraction is - a first step of adsorbing methylisopropylnaphthalene and 2,7-methylisopropylnaphthalene on a first adsorbent with a higher selectivity than other isomers, and then desorbing them with a desorbent;
The desorbed product obtained in the step is brought into contact with a second zeolite adsorbent that exhibits stronger adsorption properties for 2,7-methylisopropylnaphthalene than for 2,6-methylisopropylnaphthalene, and the 2,7-methyl contained in the desorbed product is a two-stage adsorption separation step consisting of a second step in which isopropylnaphthalene is adsorbed on the second adsorbent with a higher selectivity than 2,6-methylisopropylnaphthalene and then removed by desorption with a desorbent; and the distillation separation step. A step of circulating the low boiling point fraction and high boiling point fraction obtained in the isopropylation reaction step, and isomerizing the methyl monoisopropylnaphthalene other than 2,6-methylisopropylnaphthalene obtained in the adsorption separation step. A method for producing 2,6-methylisopropylnaphthalene, comprising a step of recycling the isomerized product to the distillation step.