JPH0466458B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field] The present invention relates to a method for adsorbing and separating a 2,6-isomer from a diisopropylene naphthalene isomer mixture. [Prior Art] Conventionally, it is widely known that terephthalic acid or 2,6-naphthalene dicarboxylic acid is subjected to a polymerization reaction with glycol in order to obtain polyester.
Polyester obtained from 2,6-naphthalene dicarboxylic acid has better physical properties such as heat resistance than those obtained from terephthalic acid, so 2,6-naphthalene dicarboxylic acid is industrially advantageous as a raw material for polyester. Establishment of a manufacturing method is desired. Conventionally, as a method for industrially producing 2,6-naphthalenedicarboxylic acid, a method using 2,6-dimethylnaphthalene as a raw material has been considered as a general method. In the case of this method, an important technical issue 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 distilling petroleum or coal tar. This dimethylnaphthalene fraction contains 2,6-dimethylnaphthalene, 2,7
- Contains isomers such as dimethylnaphthalene and 2,3-dimethylnaphthalene. Therefore, selective separation of the 2,6-isomer from such isomer mixtures presents significant difficulties. especially,
Since the boiling points of the 2,6-isomer and 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. be. Conventionally, 2,6-dimethylnaphthalene and 2,7-
As a method for industrially separating dimethylnaphthalene from a mixture of isomers, an adsorption separation method using a zeolite adsorbent has been proposed (Japanese Patent Publication No. 49-27578, Japanese Patent Publication No. 52-945).
However, in this adsorption separation method, since the 2,7-isomer is adsorbed to the adsorbent with higher selectivity than the 2,6-isomer, the ethylnaphthalene contained in the raw dimethylnaphthalene fraction is Because biphenyl, acenaphthene, etc. are very strongly adsorbed, although this method is excellent as a high-purity separation method for 2,7-isomers, it is unsatisfactory as a high-purity separation method for 2,6-isomers. belongs to. 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. [Purpose] As described above, the present inventors have discovered that in the production process of 2,6-naphthalene dicarboxylic acid using 2,6-dimethylnaphthalene as a raw material, the dimethylnaphthalene mixture used as the raw material is easily available industrially. Although it is possible to separate high-purity 2,6-dimethylnaphthalene from a dimethylnaphthalene mixture, it is recognized that it has the inherent disadvantage of significant difficulties;
It was confirmed that the production of 2,6-naphthalene dicarboxylic acid requires the development of raw materials other than dimethylnaphthalene. Therefore, as a result of intensive research to develop a process for producing 2,6-naphthalene dicarboxylic acid using raw materials other than dimethylnaphthalene as a starting material, the present inventors used diisopropylnaphthalene obtained by propylation of naphthalene. It was discovered that this purpose could be achieved by doing so. That is, according to the research of the present inventors, diisopropylnaphthalene, unlike dimethylnaphthalene, has a 2,7
The surprising fact was discovered that the 2,6-isomer is adsorbed with higher selectivity than the -isomer. Therefore, an object of the present invention is to provide a method capable of separating 2,6-diisopropylnaphthalene with high purity from a mixture of diisopropylnaphthalene isomers. [Structure] According to the present invention, when separating the 2,6-isomer from a diisopropylnaphthalene isomer mixture, the mixture is mainly treated with one or more metals selected from group a and group a metals. X type or Y type with a SiO ₂ /Al ₂ O ₃ molar ratio of 2 or more substituted with a cation of
2.
After adsorbing the 6-isomer or the 2,6-isomer and the 2,7-isomer to the first adsorbent with a higher selectivity than other isomers, the adsorbate is desorbed from the first adsorbent. a first step in which SiO ₂ /
The 2,6-isomer contained in the desorbed product is separated from other isomers by contacting it with a second zeolite adsorbent of phoriasite type having an X-type or Y-type structure with an Al ₂ O ₃ molar ratio of 2 or more. Provided is a method for adsorptive separation of 2,6-diisopropylnaphthalene, which comprises a second step of adsorbing 2,6-diisopropylnaphthalene to the second adsorbent with high selectivity and then desorbing the adsorbate from the second adsorbent. Ru. The diisopropylnaphthalene isomer mixture in the present invention can be obtained by isopropylating naphthalene with propylene and separating the diisopropylnaphthalene fraction from the resulting product. Naphthalene, which is a raw material for isopropylation, may be of any type produced from petroleum oil, coal oil, or the like. However, if it contains components that may poison the isopropylation catalyst, such as sulfur compounds or nitrogen compounds,
It is preferable to remove these compounds by methods such as conventionally well-known purification techniques, hydrorefining, and activated clay treatment. 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 solid acid catalysts such as silica/alumina, crystalline aluminosilicate, nickel oxide/silica, silver oxide/silica alumina, silica/magnesia, alumina/boria, solid phosphoric acid, aluminum chloride, hydrogen fluoride, and phosphoric acid. A Friedel-Crafts catalyst such as an acid is 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 regarded as a reciprocal reaction, and an equilibrium composition exists between naphthalene and isopropylnaphthalenes. The amount of diisopropylnaphthalene produced depends on the ratio of naphthalene and propylene in the reaction, temperature,
It depends on the type and amount of catalyst. When performing an isopropylation reaction using a Friedel-Crafts catalyst, the reaction is carried out at a temperature of room temperature to 150°C, preferably 50 to 100°C, a pressure of normal pressure to 10 atmospheres,
Catalyst to feed ratio 0.05-1.0, preferably 0.08
It is performed under the condition of ~0.5. In order to increase the yield of diisopropylnaphthalene, the molar ratio of isopropyl groups to naphthalene nuclei in the total alkylation product is between 0.5 and 3.0, preferably between 1.0 and 2.5. When using a solid acid catalyst, the reaction temperature
150~500℃, pressure 0~50Kg/ ^cm2G , contact time 0.02
~6.0hr range, preferably temperature 200-350
°C, pressure 0 to 35 Kg/cm ² G, and contact time 0.4 to 2.5 hr. 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 diisopropylnaphthalene decreases. In this isopropylation reaction step, unreacted naphthalene,
Isopropylation products containing monoisopropylnaphthalene, diisopropylnaphthalene, triisopropylnaphthalene and higher polyisopropylnaphthalenes are obtained, in which the proportion of diisopropylnaphthalene is usually 10 to 50% by weight.
It is. Next, the isopropylated product obtained in the isopropylation reaction step is subjected to a distillation treatment to separate a diisopropylnaphthalene fraction. This distillation process generally produces a low-boiling fraction consisting of naphthalene and monoisopropylnaphthalene,
It is separated into a diisopropylnaphthalene fraction and a high boiling point fraction consisting of polyisopropylnaphthalene higher than triisopropylnaphthalene. The diisopropylnaphthalene fraction obtained above is a 1,6-isomer of diisopropylnaphthalene,
Contains isomer mixtures consisting of 1,7-isomers, 1,4-isomers, 2,6-isomers, 2,7-isomers, 1,5-isomers, etc. 1,6-isomers body,
The main components include 1,7-isomer, 2,6-isomer and 2,7-isomer. In the present invention, the diisopropylnaphthalene fraction obtained above is adsorbed and separated using a zeolite adsorbent. In this case, since the polar substances contained in the diisopropylnaphthalene fraction are more strongly adsorbed by the adsorbent than diisopropylnaphthalene, it is preferable to remove them in advance. This polar substance is produced by the partial oxidation of aromatic hydrocarbons such as naphthalene and diisopropylnaphthalene, and is composed of aldehydes, ketones, alcohols, phenols, etc., and can be produced by conventionally known suitable means such as phasiasite-type zeolite, etc. It can be removed using L-type zeolite or the like. The zeolite adsorbent used in the adsorption separation treatment in the present invention is selected from among dimethylnaphthalene isomers.
- isomers are adsorbed with higher selectivity than 2,7-isomers, and such adsorbents mainly include one or two metals selected from Group A and Group A metals.
It is a phaujasite type zeolite having an X-type or Y-type structure in which SiO ₂ //Al ₂ O ₃ molar ratio is 2 or more and is substituted with more than one type of cation. Further, as the cation species, one or more metal ions selected from metals such as lithium, beryllium, potassium, magnesium, calcium, barium, strontium, and lanthanum are preferable. The most preferred adsorbent is Y-type zeolite substituted with potassium or barium cations or both. Moreover, in such a zeolite adsorbent, in addition to the metal ions, other metal ions, such as
It can contain lead, zirconium, yttrium, etc. The particle size of zeolite adsorbent is usually 3~
The capacity is approximately 300 meshes, and should be selected appropriately depending on the type of adsorption bed. Furthermore, the water content of the zeolite adsorbent can be adjusted to improve the adsorption selectivity of the 2,6-isomer. 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. Desirably, the moisture content, as measured by weight loss under scorching heat at 1000 DEG C., is in the range of 5 to 20 wt%, based on the weight of the adsorbent. The moisture content can be adjusted by adding an appropriate amount of water to the raw material mixture. In the adsorption separation process in the present invention, a diisopropylnaphthalene fraction is brought into contact with a zeolite adsorbent (hereinafter also simply referred to as an adsorbent), and the 2,6-diisopropylbenzene contained in the fraction is
After the isomer is adsorbed with a higher selectivity than the 2,7-isomer, the 2,6-isomer is desorbed from the adsorbent using a desorbent. In the adsorption step, the 2,6-isomer among diisopropylnaphthalene isomers is adsorbed with high selectivity to the adsorbent. In the desorption process, 2,6 adsorbed on the adsorbent
- the adsorbate containing isomers is desorbed from the adsorbent by means of a desorbent; The conditions for this adsorption/desorption process are a temperature of 50
~300°C, preferably 80~200°C, and a pressure of 1~20 atm, preferably 5~15 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 the raffinate by distillation, it is desirable that the boiling point difference between the desorbent and the product and the raffinate is 10°C or more, preferably 20°C or more. As such a desorbent, aromatic hydrocarbons, alkyl aromatic hydrocarbons, hydrides thereof, paraffins, etc. are usually used. In the adsorption treatment of diisopropylnaphthalene of the present invention, as described above, unlike the adsorption step of the dimethylnaphthalene isomer mixture in which the 2,7-isomer is adsorbed with higher selectivity than the 2,6-isomer, The 2,6-isomer is adsorbed with higher selectivity than the 2,7-isomer. This is a surprising fact discovered by the present inventors. The adsorption separation according to the invention may be carried out in a fixed bed, fluidized bed or preferably in a simulated moving bed system. Adsorption separation using a simulated moving bed method is already an established technology and has been applied to the adsorption separation of xylene isomer mixtures, for example, as described in Japanese Patent Publication No. 15681/1981, Japanese Patent Publication No. 10547/1983, etc. has been done. In the adsorption separation method of the present invention, as mentioned above, among the 2,6-isomer and 2,7-isomer, which are most difficult to separate from each other, for the adsorbent,
Since the 2,6-isomer can be selectively adsorbed, the desired 2,6-isomer can be separated and recovered with high purity. According to the adsorption separation technology using the above-mentioned simulated moving bed method, 99% by weight of the 2,6-isomer
It can be separated and recovered with higher purity. 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: Diisopropylnaphthalene is brought into contact with zeolite adsorbent, and 2,
The 6-isomer is selectively adsorbed and the other isomer, which is the weakly adsorbed component, is recovered along with the desorbent as a roughinate stream. (2) Concentration operation: The adsorbent that has selectively adsorbed the 2,6-isomer component is brought into contact with a portion of the extract described later, and the adsorbed components remaining on the adsorbent are expelled. 6-isomeric components are concentrated. (3) Desorption operation: The adsorbent containing the concentrated 2,6-isomer component is brought into contact with the desorbent and the 2,6-
The isomeric components are expelled from the adsorbent and recovered along 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 roughinate stream, and a portion of the desorbent contained in the adsorbent is recovered as a desorbent recovery stream. The figure shows a schematic diagram of the 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 desorbent supply line, 14 is an extract extraction line, 16 is a roughinate extraction line, and 17 is a recycle line. In the arrangement state of adsorption chambers 1 to 12 and each line 13 to 16 shown in the drawing, desorption operation is performed in adsorption chambers 1 to 3, and desorption operation is performed in adsorption chambers 4 to 6.
A concentration operation is performed in the adsorption chambers 7 to 10, an adsorption operation is performed in the adsorption chambers 11 to 12, and a desorbent recovery operation is performed in the 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 will carry out the desorption operation, adsorption chambers 5 to 7 will carry out the concentration operation, adsorption chambers 8 to 11 will carry out the adsorption operation, and adsorption chambers 12 to 1 will carry out the desorbent recovery operation. Each will be carried out. By sequentially performing such operations, adsorption separation treatment of the diisopropylnaphthalene mixture using a simulated moving bed is achieved. In addition, although the number of adsorption chambers is specified as 12 in the drawing, it should be noted that the number of adsorption chambers is not limited. In the present invention, in order to efficiently separate the 2,6-isomer from a diisopropylnaphthalene mixture using a simulated moving bed, the flow rate of each operation zone is an important operation variable, and when the feed rate is F, When expressed on a volume basis per unit time, it is preferable to set as follows. (1) Adsorption operation zone flow rate L ₁ : 0.2F+E・S＜L ₁ ＜
3.5F＋E・S (2) Concentration operation zone flow rate L ₂ : 0.2F＋E・S＜L ₂ ＜
3.5F+E・S (3) Desorption operation zone flow rate L ₃ :0.5F+E・S<L ₃ (4) Desorbent recovery operation zone flow rate L ₄ :L ₄ <0.5F+
E·S However, in the above formula, E represents the porosity of the adsorbent layer, and S represents the apparent moving speed of the adsorbent. In the adsorption operation zone, it is desirable that 2,6-diisopropylnaphthalene be adsorbed and that other isomers be adsorbed as little as possible. Furthermore, in the concentration operation zone, it is necessary to desorb isomers other than 2,6-diisopropylnaphthalene as much as possible and concentrate 2,6-diisopropylnaphthalene 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 each isomer. Next, in the desorption operation zone, it is necessary to completely desorb 2,6-diisopropylnaphthalene.
After considering the flow balance with other operating bands,
It is desirable to increase the flow rate as much as possible.
In addition, in the desorbent recovery operation zone, in order to reduce the concentration of diisopropylnaphthalene isomer in the desorbent recycled from the outlet of this zone to zero, it is necessary to keep the flow rate as low as possible so that the diisopropylnaphthalene isomer is completely adsorbed by the adsorbent. There is. Taking these into consideration, it is preferable to set the flow rate of each operation zone as described above. In addition, when implementing the adsorption separation treatment in the present invention, in order to efficiently separate the 2,6-isomer,
Preferably, it is carried out in two stages. At this time, when the mixture containing the 2,6-isomer obtained from the first-stage separation process is injected into the first-stage separation process, the desorbent contained in the mixed oil can be removed by distillation or other operations. It's fine and doesn't need to be removed. In the adsorption separation of the diisopropylnaphthalene fraction, among the diisopropylnaphthalene isomers, the 2,6-isomer is adsorbed with the highest selectivity to the adsorbent, but the 2,7-isomer is also the second most selective. It is adsorbed with high selectivity, and other isomers are hardly selectively adsorbed, or even if they are adsorbed, the selectivity is extremely small. Therefore, in order to separate the 2,6-isomer from the 2,7-isomer with high purity in a one-stage adsorption separation process, it is necessary to use an adsorption column with a large number of adsorption stages or an adsorption column with a high adsorbent packed bed. Moreover, the suction tower itself needs to have a large capacity. Therefore, the 2,6-isomer and the 2,
Taking advantage of the fact that the adsorption selectivity of other isomers is significantly lower than that of the 7-isomer, the 2,
The 6-isomer and 2,7-isomer are adsorbed and separated, and the second
In this step, it is efficient to adsorb and separate the 2,6-isomer and 2,7-isomer mixture obtained in the first step. According to such a two-stage adsorption separation method, there is no need to separate the 2,6-isomer and 2,7-isomer, which are difficult to separate from each other, in the first stage adsorption separation process. The agent can be easily selected, and the adsorption tower can have a small number of stages, and high-speed processing is possible. In the second stage adsorption separation process, the 2,6-isomer and the 2,7-isomer
- Since almost no isomers other than isomers are contained, and the amount of substances to be separated is significantly reduced, there is an advantage that the adsorption column can be small. In this two-stage adsorption separation treatment method, the zeolite adsorbent in the first stage only needs to selectively adsorb the 2,6-isomer or both the 2,6-isomer and the 2,7-isomer. The zeolite adsorbent described above is used. Preferably, X- and Y-type zeolites are substituted with group a metals or metal ions selected from group a metals, in particular potassium and/or barium ions, or in addition to the metal ions, lead, zirconium, and yttrium are substituted. Type X and type Y zeolites are used, including. The 2,6-diisopropylnaphthalene separated as described above can be converted into 2,6-naphthalene dicarboxylic acid by oxidizing it. [Effect] According to the present invention, as described above, 2,6-diisopropylnaphthalene can be produced continuously with high purity from a diisopropylnaphthalene isomer mixture. The 2,6-diisopropylnaphthalene 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 the relative separation coefficient β value of the mixed components based on 2,6-diisopropylnaphthalene when a raw material mixture containing 2,6-diisopropylnaphthalene is adsorbed using a zeolite adsorbent. It gives an index of the strength of adsorption force and is expressed by the following formula. β[i]=K[i]/K[2,6] (1) β[i] Relative separation coefficient K[i] of mixture component i: Solid-liquid equilibrium constant K[2,6] of mixture component i: Solid-liquid equilibrium constant of 2,6-diisopropylnaphthalene K[i] = weight % of component i in the adsorbed phase/weight % of component i in the liquid phase (2) K[2,6] = 2 in the adsorbed phase , 6-wt% of isomer/2 in liquid phase
, 6-weight percent of isomer (3) Example 1 A diisopropylnaphthalene isomer mixture having the composition shown in Table 1 obtained by isopropylating naphthalene with propylene and separating diisopropylnaphthalene from the product by distillation. An adsorption separation experiment was carried out using this as a raw material. The adsorbents used in the adsorption separation experiment were four types of Na-type Y-type zeolite shown in Table 2, Ba, Ba and K, Ba and Pb.
It was ion-exchanged. Ion exchange was performed by the method shown below. (Ba ion exchange) About 100 g of BaCl ₂ aqueous solution (0.5 mol/) was added to about 10 g of Na-type Y-type zeolite, and the mixture was left at a temperature of 90 to 100° C. for 2 hours. After repeating the above operation three times, it was dried and then baked at a temperature of 400°C for 3 hours. (Ba, K ion exchange) BaCl ₂ (0.5 mol/
), about 100 g of an aqueous solution of KNO ₃ (1.0 mol/) was added, and the mixture was left at a temperature of 90 to 100° C. for 2 hours. After repeating the above operation 3 times, after drying, 3 times at a temperature of 400℃
Baked for an hour. (Ba, Pb ion exchange) Approximately 20g of Y-type zeolite ion-exchanged with Ba.
Approximately 100g of 10wt% Pb(NO ₃ ) ₂ aqueous solution was added, and the temperature
It was left at 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 adsorbents are placed in an autoclave with an internal volume of 30 c.c.
About 8 g of raw material oil were charged, the temperature was kept constant while stirring, and the temperature was kept constant for 120 minutes. The adsorbent and the raw material residue were separated by filtration, and the adsorbate in the adsorbent was desorbed by Soxhlet extraction using a toluene solvent after washing the adsorbent with noso-octane. The compositions of the raw material residual liquid (liquid phase) and the adsorbate (adsorption phase) were analyzed by gas chromatography and are shown in Table 3. As is clear from the results in Table 3, the four types of zeolite adsorbents shown in Table 2 all have the property of adsorbing 2,6-diisopropylnaphthalene most strongly, and also have the property of adsorbing 2,7-diisopropylnaphthalene most strongly. It can be seen that the β value is about 1.5 times higher, and it is excellent as an adsorbent for separating 2,6-diisopropylnaphthalene.

【table】

【table】

[Table] Example 2 About 12wt of 2,6-diisopropylnaphthalene
Using the simulated moving bed apparatus shown in the drawing, 2,6-diisopropylnaphthalene was adsorbed and separated using the adsorbent A shown in Example 1 from raw material 1 shown in Table 1 of Example 1 containing %. Ivy. That is, in the pseudo moving floor device shown in the drawings,
Columns (adsorption chambers) 1 to 12 having an internal volume of 90 ml were filled with adsorbent A shown in Example 1. Raw material 1 shown in Table 1 was supplied from line 15 at a rate of 100 ml/HR, and desorbent was supplied from line 13 at a rate of 300 ml/HR. Extract 100ml/HR from line 14, and roughinate 300ml/HR from line 16.
I pulled it out with HR. At this time, column 1 was moved to 12, 11 to 10, 7 to 6, and 4 to 3 at the same time at 150 second intervals (the other columns were also moved upward one by one at the same time). Adsorption temperature is 120℃, pressure is 10
It was Kg/cm ² G. The purity of 2,6-diisopropylnaphthalene contained in the extract obtained in the above experiment on a desorbent-free basis was about 99%, and the recovery rate of 2,6-diisopropylnaphthalene was 90%. Example 3 Adsorption separation of -1 to 2,6-diisopropylnaphthalene from the raw materials shown in Table 1 was carried out using a simulated moving bed continuous chromatographic separation apparatus shown in the drawing. Separation of 2,6-diisopropylnaphthalene was carried out in two stages as shown below. First, in the first stage, 2,6-diisopropylnaphthalene and 2,7-diisopropylnaphthalene are extracted from the raw material mixture, and in the second stage, 2,6-diisopropylnaphthalene is extracted from the extract obtained in the first stage as a raw material. was separated as an extract. In the apparatus shown in the drawing, in the first stage, adsorbent columns 1 to 12 having an internal volume of 50 ml were filled with adsorbent A shown in Example 1. From line 15 to table-1
Raw material-1 shown in 1 was supplied at a rate of 100 ml/HR, and a desorbent was supplied from line 13 at a rate of 290 ml/HR. Extract 200ml/HR from line 14, and roughinate 190ml/HR from line 16.
I pulled it out with HR. At this time, columns 1 were moved to 12, 11 to 10, 7 to 6, and 4 to 3 simultaneously at 160 second intervals. Adsorption temperature is 120℃, pressure is 10
It was Kg/cm ² G. The concentration of 2,6-diisopropylnaphthalene in the extract obtained in the first stage was approximately 60 wt% on a desorbent-free basis.
The concentration of 2,7-diisopropylnaphthalene is approximately
The recovery rate of 2,6-diisopropylnaphthalene 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. Example 1 was applied to columns 1 to 12 with an internal volume of 21 ml.
was filled with adsorption liquid A. The raw material mixture is supplied from line 15 at a rate of 25ml/HR, and the desorbent is supplied from line 13 at a rate of 25ml/HR.
Supplied in ml/HR. Extract was extracted from line 14 at 25 ml/HR, and roughinate was extracted from line 16 at 25 ml/HR. At this time
Column 1 becomes 12, 11 becomes 10, every 140 seconds.
I moved 7 to 6 and 4 to 3 at the same time. The adsorption temperature is
The temperature was 120°C and the pressure was 10Kg/cm ² G. The purity of 2,6-diisopropylnaphthalene in the extract 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%.

[Brief explanation of drawings]

The drawing is a schematic diagram of an adsorption separation operation using a simulated moving bed. 1-12...Adsorption chamber, 13...Desorbent supply line, 14...Extract extraction line, 15...
... Raw material mixture line, 16 ... Roughinate extraction line, 17 ... Recycle line, 18 ... Pump.

Claims (1)

[Claims] 1 When separating the 2,6-isomer from a diisopropylnaphthalene isomer mixture, the mixture is mainly treated with SiO ₂ substituted with one or more cations selected from group a and group a metals. /
The 2,6 _- isomer or 2,6-isomer contained in the mixture is brought into contact with a first zeolite adsorbent of phagiasite type having an X-type or Y-type structure with an Al ₂ O 3 molar ratio of 2 or more. and the 2,7-isomer with higher selectivity than other isomers, and after adsorbing the first adsorbent,
a first step of desorbing the adsorbate from the first adsorbent; and a first step of desorbing the adsorbate from the first adsorbent; The 2,6-isomer contained in the desorbed product is brought into contact with a second zeolite adsorbent of the phoriasite type having an X-type or Y-type structure with a SiO ₂ /Al ₂ O ₃ molar ratio of 2 or more, and the 2,6-isomer contained in the desorbed product is 2,6-diisopropylnaphthalene, comprising a second step of adsorbing the isomer to the second adsorbent with a higher selectivity than other isomers, and then desorbing the adsorbate from the second adsorbent. adsorption separation method.