KR100884401B1 - Selective separating method of xylene and ethyl benzene from their mixture - Google Patents

Abstract

A selective separation method of xylene and ethyl benzene from their mixture is provided to refine xylene and ethylbenzene of the high purity due to high selectiveity to xylene and a simple process with high efficiency. A selective separation method of xylene and ethyl benzene from their mixture comprises a step for mixing guanidinium 4,4'- biphenyl sulfonate with a mixture of xylene and ethylbenzene. The xylene is ortho-xylene, and meta-xylene or para-xylene. The guanidinium 4,4'- biphenyl sulfonate is the crystalline powder or 4,4'- biphenyl sulfonate solution dissolved in an organic solvent such as methanol or ethanol.

Description

Selective separating method of xylene and ethyl benzene from their mixture}

The present invention relates to a method for the selective separation of xylene and ethylbenzene from a mixture of xylene and ethylbenzene, and more particularly, liquid guanidinium 4,4'- which has an affinity selectively with xylene. Guanidinium optionally contained or added to the solid xylene, which is a guest molecule, from a mixture of xylene and ethylbenzene using guanidinium biphenyl disulfonate as a host molecule A method for selectively separating xylene and ethylbenzene from a mixture by selectively inclusion of xylene inside a crystal of 4,4'-biphenyl disulfonate.

Xylene isomers are important industrial raw materials produced from naphtha crakers or reformers, which are typically o -xylene, m -xylene and para-xyl. It is obtained with a mixture of lene ( p- xylene) and ethylbenzene. And in particular, from these isomer mixtures ortho, meta-, very high para-xylene is phthalic acid (phthalic acid), iso-phthalic acid, and (iso -phthalic acid), and each being used as a raw material to make the polyester (polyester), Ethylbenzene is widely used industrially as a monomer for synthesizing styrene.

However, since these xylenes and ethylbenzenes are very similar in physical and chemical properties as isomers, they are very difficult to separate by methods using simple boiling point differences such as the conventionally used fractional distillation method. The cost of synthesizing ethylbenzene continues to rise.

Therefore, as described above, the development of the separation technology of xylene and ethylbenzene 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. U.S. Patent No. 5,135,620 proposes a method of separating ethylbenzene through extraction distillation, and U.S. Pat. Separation techniques using are also known. In addition, a method for separating isomers using biodegradable polymers having molecular imprints as host molecules has also been attempted [Korea Patent 10-0637683]. 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 4,4'-biphenyl sulfonate is one of many host molecules and has been used by Michael Ward et al for research based on host-guest molecule interaction. Michael Ward et al. Is a guest molecule whose host molecules include various aromatic compounds such as methanol, xylene, toluene, styrene and 1,4-dibromobenzene. It has been shown that guanidinium 4,4'-biphenyl sulfonate can be encapsulated in different crystal structures [ Science , 1997, 276: 575-579: J. Am. Chem . Soc ., 1997, 120: 5887-5894; Chem . Mater ., 1998, 10: 4159-4168; Chem . Mater ., 2000, 12: 1501-1504; Chem . Mater ., 2001, 13: 3018-3031.].

However, xylene and ethylbenzene are separated through a simple process with high selectivity from a mixture of xylene and ethylbenzene, which gives the superiority of the selectivity of each guest molecule from the mixture of the above guest molecules or further proposes the present invention. No attempt was made.

Accordingly, the present inventors have developed a method to efficiently separate high-purity xylene and ethylbenzene in a simple process using guanidinium 4,4'-biphenyl sulfonate in a mixture of xylene and ethylbenzene. By demonstrating that guanidinium 4,4'-biphenyl sulfonate is included with xylene and higher selectivity compared to ethylbenzene, thereby producing xylene from a mixture of xylene and ethylbenzene. And selective separation of ethylbenzene.

Accordingly, an object of the present invention is to separate high-purity xylene and ethylbenzene from a mixture of xylene and ethylbenzene through a simple process using guanidinium 4,4'-biphenyl sulfonate. To provide a way.

In order to achieve the above object, the present invention is a mixture of xylene and ethylbenzene from a mixture of xylene and ethyl benzene reacted by mixing guanidinium 4,4'-biphenyl sulfonate with a mixture of xylene and ethyl benzene. Provides a selective separation of benzene.

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.

The present invention is to separate xylene and ethylbenzene with high purity through a simple process of mixing guanidinium 4,4'-biphenyl sulfonate as a host molecule in a mixture of xylene and ethylbenzene.

Specifically, as shown in FIG. 1, in the present invention, guanidinium 4,4'-biphenyl sulfonate has a higher affinity inclusion effect on xylene than ethylbenzene as a host molecule. Simple mixing of guanidinium 4,4'-biphenyl sulfonate in a mixture of and ethylbenzene allows xylene to be optionally encapsulated in guanidinium 4,4'-biphenyl sulfonate as a guest molecule. inclusion, which effectively separates ethylbenzene.

In the present invention, xylene refers to ortho-xylene, meta-xylene or para-xylene, and among the above-mentioned xylene isomers, unlike ethylbenzene, a compound of guanidinium 4,4'-biphenyl sulfonate There is little difference in affinity.

In the present invention, guanidinium 4,4'-biphenyl sulfonate is a crystal powder of guanidinium 4,4'-biphenyl disulfonate added as a solid phase of a crystalline powder, or an organic solvent such as methanol or ethanol. A liquid guanidinium 4,4'-biphenyl disulfonate solution dissolved in can be used.

In the present invention, since guanidinium 4,4'-biphenyldisulfonate has hydrophilicity and xylene has hydrophobicity, the xylene contained in guanidinium 4,4'-biphenyldisulfonate is a liquid. It is possible to recover from guanidinium 4,4'-biphenyldisulfonate through a method such as liquid extraction. However, the present invention may be used in any method as long as it is compatible with the present invention in addition to the above-mentioned recovery method. Do.

As described above, the present invention provides a high-quality process through a simple process by mixing and treating guanidinium 4,4'-biphenyldisulfonate which exhibits a high affinity for xylene from a mixture of xylene and ethylbenzene. It was possible to efficiently separate and purify high purity xylene and ethylbenzene.

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

Example 1 Synthesis of Host Molecules

2 moles dissolved in acetone in 1 mole of 4,4'-biphenyl disulfonic acid (> 98%, purchased from Sejin Ci) (TCI) dissolved in acetone Slowly injecting guanidinimu tetrafluroborate [G (BF ₄ )] to induce crystals of guanidinium 4,4'-biphenyl disulfonate. The crystallized product was obtained. In this case, guanidinium tetrafluroborate [G (BF ₄ )] is 22.5 g (0.5 mol) of guanidine carbonate (sigma aldrich) salt and tetrafluroboric acid (48% in After reacting with 182.9 g (1 mol) of H ₂ O, Sigma Aldrich Co., Ltd. for 1 hour, the reaction product was used to obtain a guanidinium tetraborate powder obtained by drying the solvent using a rotary evaporator.

Then, the crystals were dried in a vacuum oven for 2-3 days to finally obtain apo guanidinium 4,4'-biphenyldisulfonate from which acetone was removed. It was.

Example 2 Selectivity Experiment-Solid Inclusion Reaction

Excess 25 g of solid apo guanidium 4,4'-biphenyl disulfonate was added to 10 mL of isomer mixtures of xylene and ethylbenzene, which were uniformly mixed at a ratio of 0.05 to 0.95 to 0.95 to 0.05 by volume. (apo guanidinium 4,4'-biphenyldisulfonate) host molecules were added and mixed to form a suspension.

The resulting suspension is slowly shaken using a nutator (Clay Adam, Model 1105), and the suspension is filtered again to separate the solid phase and the liquid phase, and then adhere to the surface of the solid phase. Drying in air for one day to remove guest molecules gave crystals.

The obtained crystals were subjected to gas chromatographic analysis (gas chromatography) and included in the solid molecule (guanidium 4,4'-biphenyldisulfonate) as a solid molecule (xylene and ethylbenzene). The relative amount of was determined.

The results are shown in Table 1 and FIG. 2. At this time, Figure 2 is treated with guanidium 4,4'-biphenyl disulfonate to a mixture of xylene and ethylbenzene, and after the reaction per mole fraction of xylene and ethylbenzene before the initial reaction, the guanidium 4, The molar fraction of xylene and ethylbenzene contained in 4'-biphenyldisulfonate is shown.

As a result, in the selective separation method of xylene and ethylbenzene according to the present invention, guanidium 4,4'-biphenyl disulfonate has a very selective selective inclusion effect with xylene as compared to ethylbenzene. It was found to be excellent.

[ Example  3] selectivity experiment-liquid phase Inclusion  reaction

1 mL of a mixture of xylene and ethylbenzene mixed at a constant ratio of 0.1 to 0.9 to 0.9 to 0.1 by volume is placed in a disposable test tube, and the solid apo guanidium 4,4'-biphenyl disulfonate is added to the test tube. (apo mLanidineium 4,4'-biphenyldisulfonate) A solution of 25 g of a host molecule dissolved in methanol (1 mL) was added very slowly so as not to mix with a layer of the xylene and ethylbenzene mixture to perform an inclusion reaction. 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 to make a saturated solution, and the remaining host molecule was dissolved by filtration.

When the reaction is complete and crystals are formed, the solids and liquid phases are separated by filtration, 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 determined by gas chromatography to determine the relative amount of guest molecules contained in the solid.

The results are shown in Table 2 and FIG. 3. In this case, FIG. 3 is treated with guanidium 4,4'-biphenyldisulfonate in a mixture of xylene and ethylbenzene, and then xylene and ethyl before the initial reaction. After the reaction per mole fraction of benzene, the molar fraction of xylene and ethylbenzene contained in guanidium 4,4'-biphenyldisulfonate was expressed.

As a result, in the selective separation method of xylene and ethylbenzene according to the present invention, guanidium 4,4'-biphenyl disulfonate has a selective inclusion effect with xylene over ethylbenzene. It was found to be very good.

On the other hand, in the conventional separation method of ethyl benzene and xylene, US Patent No. 4,299, 668 describes the separation effect using the conventional method Omermer gas-liquid distillation method as follows.

In other words, a mixture of 50 g of ethylbenzene and 50 g of para xylene was refluxed for 6 hours using an Osmer gas-liquid distillation method and quantitatively analyzed by gas chromatography. Ethylbenzene and 49% para xylene were mixed, and the liquid phase contained 49.5% ethylbenzene and 50.5% para xylene. This means that ethylbenzene has a relative volatility of 1.06 rather than para xylene.

In addition, a mixture of 50 g of ethylbenzene and 50 g of meta xylene was separated by an osmotic gas-liquid distillation method, and quantitative analysis was performed using gas chromatography. It was found that 51.2% ethylbenzene and 48.8% metaxylene were contained, and the liquid phase contained 49.3% ethbenzene and 50.7% metaxylene.

From the above results, the separation efficiency of ethylbenzene and xylene according to the present invention is 82.9% of xylene in case of liquid clathrate reaction when the molar fraction is 50% to 50%, as shown in Table 1 and 2. Solid phase inclusion reaction was 82% of xylene and 18% of ethylbenzene, and the separation efficiency according to the separation method of ethylbenzene and xylene described in the conventional separation method disclosed in the US patent is ethyl in the gas phase. Benzene was found to be about 51%.

Therefore, it was proved that the separation method of ethylbenzene and xylene according to the present invention showed very good separation efficiency compared to the separation method of ethylbenzene and xylene in a mixture of ethylbenzene and xylene.

1 is a schematic of the selective separation of xylene and ethylbenzene from a mixture of xylene and ethylbenzene.

Figure 2 is a graph showing the separation effect of the inclusion reaction by the guanidinium 4,4'-biphenyl disulfonate as a solid from a mixture of xylene and ethylbenzene in a preferred embodiment according to the present invention.

3 is a graph showing the separation effect of the inclusion reaction by guanidinium 4,4'-biphenyl disulfonate in the liquid phase from a mixture of xylene and ethylbenzene in a preferred embodiment of the present invention.

Figure 4 shows the chemical structural formula of guanidinium 4,4'-biphenyl disulfonate.

Claims (3)

A process for selective separation of xylene and ethylbenzene from a mixture of xylene and ethylbenzene, characterized by reacting a mixture of xylene and ethylbenzene with guanidinium 4,4'-biphenyl sulfonate. The method of claim 1, The xylene is ortho-xylene, meta-xylene or para-xylene characterized in that the selective separation of xylene and ethylbenzene from a mixture of xylene and ethylbenzene. The method of claim 1, Wherein said guanidinium 4,4'-biphenyl sulfonate is in a crystalline powder or a solution state, wherein the xylene and ethylbenzene are separated from the mixture of xylene and ethylbenzene.

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