KR20090058925A - Method for selective separation of xylene isomer with guanidinium 4-iodobenzene sulfonate host compound - Google Patents

Abstract

A selective separation method of xylene isomer is provided to efficiently separate xylene isomer from a mixture of the xylene isomer by using a guanidinium 4-iodobenzene sulfonate host compound showing different affinity according to xylene isomers. A selective separation method of xylene isomer comprises the steps of: manufacturing host-saturated solution by dissolving guanidinium 4-iodobenzene sulfonate host molecules in methanol solution to prepare host-saturated solution; performing inclusion reaction by slowly adding the saturated solution to the mixture of the xylene isomer; when crystals are formed, filtering the product to separate solid and liquid; washing the solid with cold methanol and then drying the washed methanol to obtain crystals; and calculating the content of each xylene isomer by using a gas chromatography.

Description

Method for selective separation of xylene isomers with guanidinium 4-iodobenzene sulfonate host compound

The present invention relates to a method for the selective separation of xylene isomers by guanidinium 4-iodobenzene sulfonate, and more particularly, xylene isomers composed of ortho-xylene, meta-xylene and para-xylene. Selected xylene isomers having a relatively high affinity from mixtures of xylene isomers using guanidinium 4-iodobenzene sulfonate, which has a different affinity to the liver, as a host molecule. By the inclusion (inclusion), it is possible to efficiently separate the xylene isomers with high purity through a simple process.

Xylene isomers are important industrial raw materials produced from naphtha crakers or reformers, typically o -xylene, m -xylene, and para- Obtained as a mixture of xylene ( p -xylene). And in particular, the ortho-isomer from these mixtures, meta-, and para-xylene are phthalic acid (phthalic acid), iso-industrially it is respectively used as a raw material to make the acid (iso -phthalic acid), and polyester (polyester) It is widely used.

However, since these xylene isomers have very similar physicochemical properties, their separation is very difficult by methods using simple boiling point differences such as the conventionally used fractional distillation.

Therefore, as described above, the development of xylene isomer separation technology is very important in the petrochemical field, and many researches and prior arts for improving the separation method of these isomers have been reported for a long time. US Pat. Nos. 5,445,715 and 5,039,380 attempt to separate meta-xylene using an azeotropic distillation method developed from existing distillation methods, and U.S. Pat. Nos. 4,676,875, 4,676,872, 4,673,465, 4,585,526 and 4,488,937 attempt to separate meta-xylene using extractive distillation. In addition, US Pat. Nos. 5,900,523 and 5,382,747 propose methods for separating meta-xylene using zeolites as adsorbents. However, these prior art may be different from the technology to be achieved in the present invention, such as relatively high installation and maintenance costs, complicated processes, low selectivity.

Guanidinium 4-iodobenzene sulfonate is one of many host molecules and has been used by Michael Ward et al. For research based on host-guest molecule interactions. Michael Ward ortho as a guest molecule-xylene (o -xylene), meta- xylene (m -xylene), para-xylene (p -xylene), such as a host molecule, guanidinyl nium 4-iodo-benzenesulfonate It has been shown that each can be entrapped in a host molecule by guanidinium 4-iodobenzene sulfonate [Angew. Chem. Int. Ed. 40 (2001) 4045-4048.

However, these host molecules have shown superiority in the selectivity of each guest molecule from the mixture of xylene guest molecules, or moreover, meta-xylene can be prepared using host molecules having high selectivity from the xylene mixture as proposed in the present invention. There was no attempt to separate it.

Accordingly, the present inventors have developed a method to efficiently separate xylene isomers by using a host molecule of guanidinium 4-iodobenzene sulfonate in a mixture between xylene isomers. Xylene mixtures by demonstrating that guanidinium 4-iodobenzene sulfonate is selectively included with meta-xylene, ortho-xylene and para-xylene with different affinity. We have completed the method of separating xylene isomers with high purity.

Accordingly, an object of the present invention is to provide a selective separation method capable of purifying high purity xylene isomers with high efficiency through a simple process using guanidinium 4-iodobenzene sulfonate in a mixture of xylene isomers. .

In order to achieve the above object, the present invention by reacting a mixture of guanidinium 4-iodobenzene sulfonate in a xylene isomer mixture, the affinity for guanidinium 4-iodobenzene sulfonate mutually Provided is a method for selective separation of xylene isomers that separates other xylene isomers.

Hereinafter, the present invention will be described in detail.

At this time, if there is no other definition in the technical terms and scientific terms used, it has a meaning commonly understood by those of ordinary skill in the art.

In addition, repeated description of the same technical configuration and operation as in the prior art will be omitted.

In the present invention, xylene isomers refer to meta-xylene, ortho-xylene and para-xylene.

The present invention has a different affinity for guanidinium 4-iodobenzene sulfonate through a simple process of mixing and crystallizing guanidinium 4-iodobenzene sulfonate as a host molecule in a mixture of xylene isomers. Xylene isomers can be separated with high purity. Specifically, since guanidinium 4-iodobenzene sulfonate has inclusion affinity of different affinity according to the type of xylene isomer as host molecule, guanidinium 4-iodo in a mixture of xylene isomers By mixing and reacting the benzene sulfonate, a relatively affinity xylene isomer with guanidinium 4-iodobenzene sulfonate is selectively added to the guanidinium 4-iodobenzene sulfonate as a guest molecule. It will be encapsulated so that it can be efficiently separated from the relatively low affinity xylene isomers with guanidinium 4-iodobenzene sulfonate. In this case, the present invention is the world's first affinity for guanidinium 4-iodobenzene sulfonate among the xylene isomers in the order of meta-xylene> ortho- xylene> para-xylene.

Accordingly, the present invention, in view of the difference in relative affinity described above, in the mixture of two or more kinds of xylene isomers, is not surrounded by the xylene isomers and the xylene isomers that are included in the guanidinium 4-iodobenzene sulfonate. By separating, it is possible to obtain a high purity xylene isomer consisting of one type of xylene isomer. As a specific example, the method for separating each xylene isomer from a mixture of xylene isomers consisting of meta-xylene, ortho-xylene and para-xylene is carried out on the mixture of guanidinium 4-I in the mixture of xylene isomers. Dodobenzene sulfonate was mixed to firstly encapsulate and crystallize meta-xylene, which has a relatively higher affinity than ortho-xylene and para-xylene, and then recover the encapsulated meta-xylene from the crystallization, and remaining xyl Remixing guanidinium 4-iodobenzene sulfonate to the ene isomer mixture to encapsulate and crystallize ortho-xylene, which has a higher affinity than para-xylene, to recover the encapsulated ortho-xylene from the crystallization , Meta-xylene, ortho-xylene and para-xylene can be separated into high purity, respectively.

In the present invention, the mixture of xylene isomers refers to a mixture of xylene isomers selected from at least two species in the group consisting of meta-xylene, ortho-xylene and para-xylene, specifically, ortho-xylene and meta-xylene Or mixtures of meta-xylene and para-xylene, mixtures of ortho-xylene and para-xylene or mixtures of ortho-xylene, meta-xylene and para-xylene.

In the present invention, guanidinium 4-iodobenzene sulfonate may be used in the liquid phase dissolved in an organic solvent such as methanol or ethanol depending on the type of solvent of the crystal powder or xylene mixture.

In the present invention, since guanidinium 4-iodobenzene sulfonate has hydrophilicity and xylene has hydrophobicity, the xylene isomer contained in guanidinium 4-iodobenzene sulfonate may be subjected to liquid-liquid extraction. It is possible to recover from guanidinium 4-iodobenzene sulfonate through the method. However, the present invention may be any method other than the above-mentioned recovery method as long as it is compatible with the present invention.

1 is a schematic diagram illustrating a selective separation process of xylene isomers according to the present invention, and a mixture of xylene isomers is mixed with guanidinium 4-iodobenzene sulfonate as a host molecule and has a relatively high affinity. The xylene isomer, which is a guest molecule, is entrapped and induced to crystallize, and the crystallized (solid) obtained by filtration is separated from the guest molecule and the host molecule through liquid-liquid extraction, and then the reuse of the host molecule is illustrated. will be.

As described above, the present invention can efficiently separate and purify xylene isomers through a simple process in a mixture of xylene isomers using guanidinium 4-iodobenzene sulfonate having different affinity for each xylene isomer. Made it possible.

Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited by the following examples, and various modifications or changes can be made within the spirit and scope of the present invention to those skilled in the art.

[Example]

<Host Molecular Synthesis>

9 g of 4-iodobenzenesulfonyl chloride (95%) is added to 20 mL of 1,4-dioxane, where 1,4-dioxane is 4-iodobenzene sulfonyl chloride. Was used as a solvent to dissolve the 4-iodobenzene sulfonyl chloride, and any solvent that did not participate in the reaction could be dissolved), and then 3 g of distilled water was mixed with this solution. At this time, the amount of distilled water in the reaction should be matched to the amount of 4-iodobenzene sulfonyl chloride one to one equivalent, but since the reaction is easy to put more than one to one equivalent, the excess amount of distilled water in this synthesis Was used.

Then, the mixture solution was refluxed at 100 ° C. for 6 hours to prepare 4-iodobenzene sulfonic acid. At this time, unreacted water was removed using a rotary evaporator.

The 4-iodobenzene sulfonic acid prepared above was dissolved in acetone, and the solution was dissolved in a solution of guanidinium tetrafluroborate [G (BF ₄ )] in acetone. Guanidinium 4-iodobenzene sulfonate was synthesized by slow reaction. At this time, 4-iodobenzene sulfonic acid and guanidinium tetraborate were adjusted to 1: 1 equivalent.

The synthesized guanidinium 4-iodobenzene sulfonate was separated from the acetone solution, and then vacuum oven was removed to remove acetone contained in the guanidinium 4-iodobenzene sulfonate which is the host molecule in the present invention. Dried for 2 days. At this time, whether or not acetone is included in the dry host molecule was confirmed using the acetone characteristic peak through hydrogen nuclear magnetic resonance analysis.

In addition, the guanidinium tetraborate is guanidine carbonate (guanidine carbonate (99%), purchased from Sigma Aldrich) salt 22.5 g (0.5 mol) of tetrafluroboric acid (48 wt.% In H ₂ O, 182.9 g (1 mol) of Sigma Aldrich Co., Ltd. solution was mixed and reacted for about an hour, and the reaction solution was a guanidinium tetraborate powder obtained by drying a solvent using a rotary evaporator.

<Selectivity Experiment>

Xylene isomer mixtures uniformly mixed at a ratio of 0.1 to 0.9 to 0.9 to 0.1 by volume (ortho-xylene and meta-xylene, ortho-xylene and para-xylene, meta-xylene and para-, respectively) 1 mL of xylene) was placed in a disposable test tube, and the solution containing the solid apo guanidium 4-iodosulfonate host molecule dissolved in methanol was slowly added so as not to mix with the layer of the xylene mixture. It was. At this time, the methanol solution in which the host molecule was dissolved was dissolved until the host molecule was no longer dissolved in the methanol solution. Then, the remaining host molecule was dissolved and used as a saturated solution.

When the reaction is complete and crystals are formed, it is filtered to separate solids and liquids, and the obtained solids are washed three times with cold methanol solution and dried to remove the guest molecules adhering to the surface. Crystals were obtained.

The obtained crystals were subjected to gas chromatographing (gas chromatography) to include guest molecules (ortho-xylene, meta-xylene, and the like) contained in the solid (guanidium 4-iodobenzene sulfonate) solid. Para-xylene) was determined.

The results are shown in Tables 1, 2, and 3 and FIG. In this case, Table 1 shows the results for the mixture of ortho-xylene and meta-xylene, Table 2 shows the results for the mixture of meta-xylene and para-xylene, Table 3 is ortho-xyl Results are shown for a mixture of lene and para-xylene. FIG. 2 also shows that the xylene mixture is treated with guanidinium 4-iodobenzene sulfonate and then embedded in guanidinium 4-iodobenzene sulfonate after the reaction per mole fraction of the xylene mixture before the initial reaction. Molar fraction of xylene isomers.

As shown in Tables 1 to 3 and FIG. 2, the guanidinium 4-iodobenzene sulfonate in the selective separation method of the xylene isomer according to the present invention has very selective inclusion effect depending on the type of xylene isomer. It was found to be excellent.

That is, in the present invention, guanidinium 4-iodobenzene sulfonate has a different affinity clathability according to the type of xylene isomer, and the affinity of the clathrate is meta-xylene, ortho-xylene and para. -Xylene's innocence was known.

In addition, meta-xylene and ortho-xylene are excellent in separation efficiency when the concentration is at least 30% and in the meta-xylene and para-xylene mixture when the concentration of meta-xylene is at least 50%, In the mixture of ortho-xylene and para-xylene, the separation efficiency is excellent when the concentration of ortho-xylene is at least 30% or more.

Meanwhile, in the conventional separation method of meta xylene, the separation effect using the extractive distillation method is described in the US patent as follows.

In U.S. Patent 4,488,937, a solution of 50 g of meta-xylene and 50 g of ortho-xylene was refluxed for 12 hours using an Osmer type vapor-liquid equilibrium, followed by gas chromatography. As a result of the analysis, 51.8% meta-xylene and 48.2% ortho-xylene were present in the gas phase, and 49% meta-xylene and 51% ortho-xylene were present in the liquid phase. To improve this conventional method, 50 g of ethyl-2-hydroxyoxybenzoate was added to a mixture containing 25 g of meta-xylene and 25 g of ortho-xylene as an extractive distillation method. After 11 hours of reflux, meta-xylene was 56.3% in the gas phase and ortho-xylene was 43.7%, which was 4.5% (7.3% by liquid level) compared to conventional distillation. . Similarly, distillation for 9 hours using this method yielded 55% meta-xylene and 45% ortho-xylene in the gas phase. Therefore, it was confirmed that the longer the distillation time, the higher the purity.

When comparing the results of the conventional separation method of xylene isomers and the separation method according to the present invention, the separation efficiency of meta-xylene from meta-xylene and ortho-xylene according to the present invention is shown in Table 1. As a result of the inclusion reaction when the mole fraction is 50% to 50%, meta-xylene is separated by 85.0% and ortho-xylene is separated by 15.0%, which is at least 28.7% of the separation efficiency described in the conventional separation method disclosed in the US patent. It turned out to be higher.

In US Pat. No. 5,093,723, extractive distillation was carried out using methyl balerate for 2 hours in a solution of 50 g of para-xylene and 70 g of meta-xylene. It is known that para-xylene and 20.7% meta-xylene were obtained and 36.7% para-xylene and 63.3% meta-xylene were obtained below the tower. In addition, 8 hours of para-xylene and 14.4% of meta-xylene were obtained on the tower under the same conditions for 8 hours, and 35.9% of para-xylene and 64.1% of meta-xylene were placed on the bottom of the tower. Got it.

Comparing the results of the separation technique of the conventional xylene isomer and the separation method according to the present invention, the separation efficiency of the meta-xylene and para-xylene according to the present invention is as shown in Table 2, the mole fraction is The inclusion of 60% (meta-xylene) vs. 40% (para-xylene) in a similar range results in 79.7% of meta-xylene and 20.3% of para-xylene. It was found that the degree of meta-xylene separation was at least 15.6% higher than the conventional separation method disclosed.

Thus, it has been demonstrated that the method for separating meta-xylene in the mixture of xylene isomers according to the present invention shows a very good separation efficiency compared to the method for separating meta-xylene from a mixture of xylenes.

1 is a schematic diagram illustrating a selective separation process of xylene isomers according to the present invention,

Figure 2 shows the separation effect of the inclusion reaction according to the mixture of the mixture of xylene isomers and guanidinium 4-iodobenzene sulfonate according to the present invention,

Figure 3 is a chemical structural formula showing the molecular structure of guanidinium 4-iodobenzene sulfonate.

Claims (2)

It is characterized by separating xylene isomers having different affinity for guanidinium 4-iodobenzene sulfonate by mixing and reacting guanidinium 4-iodobenzene sulfonate with a mixture of xylene isomers. Selective Separation Method of Xylene Isomers. The method of claim 1, The mixture of xylene isomers is a mixture of ortho-xylene and meta-xylene, a mixture of meta-xylene and para-xylene, a mixture of ortho-xylene and para-xylene or ortho-xylene, meta- A method for the selective separation of xylene isomers, characterized in that it is a mixture of xylene and para-xylene.

Images