KR101741295B1 - Method of preparing aromatic iodide compounds - Google Patents

Abstract

The present invention relates to a process for preparing an aromatic iodide compound, characterized in that an aromatic compound and an iodine component are introduced into an upper layer of a zeolite catalyst layer and are passed in a gaseous phase to produce an aromatic iodide compound, wherein the zeolite catalyst layer is composed of two or more continuous layers. The selectivity and productivity of the compound can be increased and the unreacted iodine and aromatics can be minimized.

Description

TECHNICAL FIELD The present invention relates to a method for preparing aromatic iodide compounds,

The present invention relates to a process for producing aromatic iodide compounds, and more particularly, to a process for producing aromatic iodide compounds by applying a zeolite catalyst layer composed of two or more continuous layers, thereby increasing the selectivity and yield of the p-iodide compound and minimizing the unreacted iodine and aromatic substances And a method for producing an aromatic iodide compound.

BACKGROUND ART Para-dichlorobenzene, produced by reacting benzene with chlorine, is used as a raw material for engineering plastics such as polyphenylene sulfide (PPS), which is typical of a technique for producing an aromatic halogen compound by reacting a halogen compound with an aromatic compound such as benzene or naphthalene. PPS is prepared by polymerization reaction of paradichlorobenzene and sodium sulfide in N-methylpyrrolidone solvent. However, since the above process is difficult to obtain a polymer having a high molecular weight, a high molecular weight polymer is obtained through a post-process called hardening. The obtained PPS has a disadvantage that it is fragile due to a crosslinking reaction or the like. In addition, a metal salt such as sodium chloride is inevitably generated as a reaction by-product in the polymerization process, thereby causing serious problems in economical efficiency of the commercial process and physical properties of the polymer.

In addition, the method of preparing p-iodide benzene by reacting benzene with iodine in an oxygen atmosphere using a zeolite catalyst has a high conversion rate and a high selectivity of a commercially preferred p-iodide compound, as well as a high yield of benzene or naphthalene Can be minimized.

However, in order to use this iodination technique more commercially, the productivity of the diiodide compound and the selectivity of the para-iodide compound should be further improved. According to the prior art, carbon deposits are generated by the combustion of the raw materials, and the catalysts lose their activity. Furthermore, the carbon deposits or polyvalent iodinated polymer impurities produced in this way not only lose the activity of the catalyst but also come out in the iodide product, thereby causing serious problems in the subsequent purification process.

In order to increase the yield of the p-iodide compound, the molar ratio of iodine to benzene introduced should theoretically be in a molar ratio of 1: 1, but in practice, a molar ratio of 0.3: 0.6 to 1 is appropriate. However, even in the previous molar ratio, unreacted iodine is formed as it passes through the catalyst bed, which accelerates the corrosion or provides an unfavorable process condition when recovering iodine at the end of the process. However, when the molar ratio of iodine to benzene is 0.1 to 0.4: 1, the amount of unreacted iodine can be reduced. However, the amount of iodine to be reacted with benzene is insufficient, There is a problem.

An object of the present invention is to solve the above problems of the prior art, and it is an object of the present invention to provide a zeolite catalyst layer comprising two or more continuous layers, iodine and benzene being added thereto at the same time to reduce the amount of unreacted iodine remaining in the entire process, To provide a method for enhancing the reproducibility of the paradiiodine compound.

Another object of the present invention is to provide a process for producing an aromatic iodide compound capable of minimizing unreacted iodine and aromatic substances while enhancing selectivity and yield of the iodide compound.

In order to accomplish the object of the present invention, the present invention is characterized in that an aromatic compound and a periodic iodine component are introduced into an upper layer of a zeolite catalyst layer and are passed in a gaseous phase to produce an aromatic iodide compound, wherein the zeolite catalyst layer is composed of two or more continuous layers By weight based on the weight of the aromatic iodide compound.

According to the present invention, in the process for producing an aromatic iodide compound, the selectivity and the yield of the p-iodide compound can be increased, and the iodine and the aromatic substance which are not reacted can be minimized.

1 is a process diagram showing a production flow of an aromatic iodinated compound according to an embodiment of the present invention.
2 is a process diagram showing a production flow of an aromatic iodide compound according to the prior art.

The process for producing an aromatic iodide compound according to the present invention is characterized in that an aromatic compound and an iodine component are used as raw materials to pass through a zeolite catalyst layer in a gaseous phase to produce an aromatic iodide compound, wherein the zeolite catalyst layer is composed of two or more continuous layers.

For reference, in the present invention, the continuous layer may refer to a layer structure including a series connection or a parallel connection unless otherwise specified, and may be a serial connection in particular.

For example, the series connection may be one in which a zeolite catalyst layer is connected in series in the first reactor or a plurality of reactors in which a zeolite catalyst layer is packed in series.

As a specific example, the zeolite catalyst layer may have two to five continuous layer structures in the first reactor or two to ten zeolite catalyst layers Or may be to form a continuous layer in a series connection structure.

In the reactor in which the zeolite catalyst layer is packed, the zeolite catalyst layer can be freely filled, and in order to facilitate the smooth flow of the feed or the generated gas, an alumina ball, a glass ball, a quartz wool Lt; / RTI > For example, the catalyst layer may be 10 to 100%, 20 to 90%, 30 to 80%, or 40 to 60% filled in the reactor.

The aromatic compound may be at least one selected from the group consisting of benzene, naphthalene and biphenyl. Specifically, benzene is mainly used, but the present invention is not limited thereto.

The iodine component may be an iodine, an iodine compound or a monoiodide compound, collectively referred to as an iodine component.

The iodine compound may be, for example, a diiodide compound of an aromatic compound such as diiodobenzene, diiodonaphthalene and diiodobiphenyl, or a triiodide compound of an aromatic compound, and the monoiodide compound may be monoiodobenzene, monoiodonaphthalene, Monoiodobiphenyl, and monoiodobiphenyl.

The double iodine component may be I ₂ (Element Iodine), and mono-iodobenzene among the monoiodide compounds may be used.

The zeolite catalyst layer may be composed of at least one zeolite selected from ZSM-5, ZSM-22, zeolite X and zeolite Y, and may be a zeolite of Na-13X zeolite.

The use of the zeolite catalyst layer as two or more continuous layers or two to five continuous layers can maximize the reactivity between the iodine component and the aromatic compound.

In this regard, the apparatus shown in FIG. 1 is configured to repeat the process of obtaining an aromatic iodide compound by a gas phase reaction twice when the iodine component and the aromatic compound are introduced into the upper layer of the zeolite catalyst layer. For reference, the apparatus shown in FIG. 2 is configured to obtain an aromatic iodide compound by a gas phase reaction when an iodine component and an aromatic compound are introduced into an upper layer of a zeolite catalyst layer.

It is known that the iodination reaction of an aromatic material using the zeolite catalyst occurs at a temperature of 200 to 400 ° C. The higher the reaction temperature, the higher the conversion rate of the aromatic compounds and the monoiodide compounds as raw materials, while the lower the selectivity and production rate of the most valuable commercially available paradiiodine compounds. On the other hand, the reaction pressure can also be performed in various regions, and the higher the reaction pressure, the more efficient the iodination reaction.

The molar ratio of the iodine component to the aromatic compound used as the raw material is 0.05 to 1: 1, and is in the range of 0.1 to 0.75: 1, or 0.5 to 0.75: 1. It is possible to maximize the selectivity and yield of the p-iodide compound within the above range.

In the present invention, it is preferable that the iodine component and the aromatic compound are charged at a time in consideration of the rapid progress of the reaction.

However, the iodine component and the aromatic compound may be separately added to the zeolite catalyst layer as required. In this case, the feed line of the iodine component and the aromatic compound introduced into the middle of the zeolite catalyst layer may be one or more in the middle layer, and the input ratio of the upper layer and the middle layer may be any form. Specifically, the iodine component injected into the upper layer of the zeolite catalyst layer And the amount of iodine added to the intermediate layer may be 95 to 50:50 to 5, when the total amount of iodine is 100% by weight.

In this case, it may be put in the middle of the zeolite catalyst layer, and the height of the input line and the input ratio are determined according to the number of input lines of the iodine component. That is, when the input line = n, the ideal input height is the catalyst layer height X = (1 / (1 + n)) and the input ratio is Y = (1 / / 10. ≪ / RTI > In this case, n may be an integer of 1 or more, an integer of 2 or more, or an integer of 2 to 4.

The aromatic iodide compound may be a paradi iodide compound.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope and spirit of the invention as disclosed in the accompanying claims. Changes and modifications may fall within the scope of the appended claims.

[Example]

Example  One

First, an apparatus as shown in Fig. 1, which is configured to repeat the step of obtaining an aromatic iodide compound by a gas phase reaction twice, when an iodine component and an aromatic compound are fed into an upper layer of a zeolite catalyst layer, is prepared.

Specifically, a tube type reactor was charged with Na-13X zeolite Two 50 cm length reactors fully loaded with the catalyst bed were prepared and then configured to be continuous.

Among the above-mentioned reactors, a zeolite catalyst layer 42.25 g of benzene per hour and 109.27 g of iodine (molar ratio of iodine / benzene = 0.75) were introduced into the flask, and 39.7 parts by weight of a paradiiodine compound was obtained. The reaction was carried out in an oxygen atmosphere at 280 캜.

For reference, it was confirmed by gas chromatography analysis whether a p-iodide compound was present. Since iodine was not detected on gas chromatography, only a substance to be analyzed was analyzed to obtain a weight value, and then the content of the p-iodide compound (* Notation in the table).

Example  2

67.35 g of benzene per hour and 109.27 g of iodine (molar ratio of iodine / benzene = 0.50) were charged into the upper portion of the zeolite catalyst layer of the apparatus as shown in Fig. 1, and 31.3 parts by weight of the paradiiodine compound was obtained. The reaction was carried out in an oxygen atmosphere at 280 캜 under specific reaction conditions.

Comparative Example  One

Unlike the one used in Example 1, one reactor having a length of 100 cm, which was configured to perform an independent process of obtaining an aromatic iodide compound by a gas phase reaction when an iodine component and an aromatic compound were introduced into an upper layer of a zeolite catalyst layer, .

Specifically, a tube type reactor was charged with Na-13X zeolite One reactor was completely charged with the catalyst layer, and 42.25 g of benzene and 109.27 g of iodide (iodine / benzene mol ratio = 0.75) per hour were fed into the upper portion of the zeolite catalyst layer in the reactor, and 22.1 parts by weight of a paradiyiodine compound was obtained Respectively. The reaction was carried out in an oxygen atmosphere at 280 캜.

Comparative Example  2

67.35 g of benzene per hour and 109.27 g of iodide (molar ratio of iodine / benzene = 0.50) were charged into the upper portion of the zeolite catalyst layer of the apparatus as shown in Fig. 2, and 22.0 parts by weight of the paradiiodic compound was obtained. The reaction was carried out in an oxygen atmosphere at 280 캜 under specific reaction conditions.

The results are summarized in Table 1 below.

Remarks Example 1 Example 2 Comparative Example 1 Comparative Example 2 Total input iodine: benzene mole ratio 0.75: 1 0.50: 1 0.75: 1 0.50: 1 Amount (parts by weight) of the paradiiodine compound in the product * 39.7 31.3 22.1 22.0

As shown in Table 1, when the total molar ratio of iodine to benzene was the same (Example 1, Comparative Example 1, Example 2 and Comparative Example 2), the catalyst layer was repeated two or more times as shown in FIG. It was found that the productivity of the paradiiodine compound can be increased by passing the solution. In addition, it can be deduced that the residual iodine content will be relatively improved because the productivity of the p-iodide compound increases.

Claims (11)

An aromatic compound and an iodine component are introduced into an upper layer of a zeolite catalyst layer and passed through a gas phase to produce an aromatic iodide compound,
The zeolite catalyst layer does not include a separation step of separating the unreacted raw material and the product between the catalyst layers with two or more continuous layer structures,
Wherein the molar ratio of the iodine component to the aromatic compound is from 0.75 to 1: 1.
The method according to claim 1,
Wherein the continuous layer is a series-connected structure.
The method according to claim 1,
Wherein the zeolite catalyst layer has 2 to 5 continuous layer structures in one reactor.
The method according to claim 1,
Wherein the zeolite catalyst layer forms a continuous layer with 2 to 10 series-connected structures in a reactor packed with a catalyst layer.
5. The method of claim 4,
Wherein the zeolite catalyst layer is packed at 10 to 100% in each reactor.
The method according to claim 1,
Wherein the aromatic compound is at least one selected from the group consisting of benzene, naphthalene and biphenyl.
The method according to claim 1,
Wherein the iodine component is at least one selected from the group consisting of iodine, an iodine compound, and a monoiodide compound.
8. The method of claim 7,
Wherein the monoiodide compound is at least one selected from the group consisting of monoiodobenzene, monoiodonaphthalene, and monoiodobiphenyl.
delete The method according to claim 1,
Wherein the aromatic iodide compound is a p-iodide type.
The method according to claim 1,
Wherein the zeolite catalyst layer comprises at least one zeolite selected from ZSM-5, ZSM-22, zeolite X, and zeolite Y.

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