HK1142590B - Method of preparing iodinated aromatic compounds - Google Patents

Description

Process for preparing iodinated aromatic compounds

Technical Field

The present invention relates to a method for preparing iodinated aromatic compounds, and more particularly, to a method for preparing iodinated aromatic compounds, which comprises the steps of: comprising an aromatic compound, a diiodized aromatic compound or water, and iodine (I) in the presence of a zeolite catalyst and oxygen₂) Iodinating the mixture of (1).

Background

Processes for preparing halogenated aromatic compounds using reactants comprising an aromatic compound such as benzene or naphthalene and a halogen (bromine, chlorine, iodine, etc.) have been of interest in the industrial field. Particularly, among the above halogenated aromatic compounds, p-diiodobenzene (p-DIB) is widely used as a reactant for Producing Polyphenylene Sulfide (PPS), which is commercially valuable, and thus research for improving the productivity of p-DIB has been actively conducted.

For example, as shown in FIG. 1As shown, U.S. Pat. Nos. 4,778,938 and 4,746,758 disclose the use of benzene and iodine (I) in the presence of a zeolite catalyst and oxygen₂) A process for preparing p-DIB as a reactant. According to these prior art techniques, these preparation methods have advantages in terms of conversion in the production of p-DIB. In addition, these processes can also minimize the oxidation of benzene or naphthalene according to the above-mentioned prior art disclosures.

However, the above-mentioned method has a disadvantage in controlling the temperature of the iodinating reactor, which is associated with a large amount of exothermic reactions occurring locally. As a general rule, the iodination of aromatic compounds is necessarily accompanied by the oxidation of hydrogen iodide (hydroiodic acid, HI) in the presence of a zeolite catalyst and oxygen. This oxidation of HI is a largely exothermic reaction and thus increases the temperature in the centre of the iodinating reactor. Under such high temperature conditions, both iodination and combustion of reactants are very violent and thus cause a large amount of runaway reaction. Furthermore, when these production methods are used in plant scale and the plant is designed, temperature control becomes more important and is a priority because the diameter of the reactor should be designed to be sufficiently large.

Furthermore, under such high temperature conditions, the combustion reaction of the reactants can cause the formation of impurities, such as carbon deposits, which deactivate the catalyst and thus shorten the replacement cycle of the catalyst. In addition, since it is difficult to control the temperature of the iodinating reactor, the feed flow rate of the reactants cannot be increased, so that productivity is lowered.

Disclosure of Invention

To solve the problems of the above conventional methods, the present invention provides a method for preparing iodinated aromatic compounds, which is capable of stably and reliably controlling the temperature of an iodinating reactor, thereby improving productivity per unit weight of a catalyst and suppressing side reactions forming impurities.

One embodiment of the present invention relates to a method for preparing iodinated aromatic compounds, comprising:

comprising an aromatic compound, a diiodized aromatic compound or water, and iodine (I) in the presence of a zeolite catalyst and oxygen₂) Iodinating the mixture of (1).

The aromatic compound may be selected from benzene, naphthalene and biphenyl.

Further, the diiodoated aromatic compound may be selected from the group consisting of diiodobenzene, diiodonaphthalene and diiodobiphenyl.

In order to stably and reliably control the temperature of the iodinating reactor, the diiodoated aromatic compound and water may be used in molar ratios of 2 to 10mol% and 5 to 30mol%, respectively, with respect to the aromatic compound.

Further, the zeolite catalyst may be selected from Na-13X zeolite, Y-type zeolite, ZSM5 zeolite, and K-13X zeolite.

More preferably, the zeolite catalyst may be a Na-13X zeolite.

In addition, the iodination reaction may be performed at 230 ℃ -.

The method of the present invention may further comprise:

recycling a di-iodo aromatic compound comprising a p-di-iodo aromatic compound, an o-di-iodo aromatic compound and a m-di-iodo aromatic compound,

wherein the diiodoated aromatic compound is obtained by:

distilling the mixture of the aromatic compound, the diiodoated aromatic compound or water, and iodine (I)₂) The mixture obtained was subjected to iodination, and the distillate was subjected to crystallization and solid-liquid separation.

The method for preparing iodinated aromatic compounds according to the present invention may further include:

transferring an iodinated product obtained from a mixture comprising the aromatic compound, the diiodoated aromatic compound or water, and iodine from an iodinating reactor (R01) to a first distillation column (C10), and then separating and recovering the aromatic compound and water from the iodinated product at the top of the first distillation column (C10);

transferring the distillate from the bottom of the first distillation column (C10) to a second distillation column (C20), and then separating and recovering monoiodinated aromatic compounds and iodine from the distillate at the top of the second distillation column (C20);

transferring the distillate from the bottom of the second distillation column (C20) to a third distillation column (C30), and then separating and recovering p-diiodized aromatic compounds, o-diiodized aromatic compounds and m-diiodized aromatic compounds from the distillate at the top of the third distillation column (C30) and transferring them to a crystallization and solid-liquid separator (D10);

separating and recovering the solid-phase p-diiodinated aromatic compound and a mother liquor comprising the liquid-phase p-diiodinated aromatic compound, the o-diiodinated aromatic compound and the m-diiodinated aromatic compound from the crystallization and solid-liquid separator (D10); and

recycling the diiodized aromatic compound by feeding a portion of the mother liquor to an iodinating reactor (R01).

Drawings

For a more complete understanding of the present invention and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a schematic view showing a process for preparing iodinated aromatic compounds according to comparative examples 1 and 2;

FIG. 2 is a schematic view showing a process for preparing iodinated aromatic compounds according to examples 1 and 2;

FIG. 3 is a schematic diagram showing a process for preparing iodinated aromatic compounds and recycling a diiodiated aromatic compound in the form of a poorly co-soluble mixture, according to one embodiment of the present invention; and

fig. 4 is a detailed view of the iodinating reactor (R01).

Detailed description of the reference numerals

R01: iodination reactor C10: a first distillation column

C20: second distillation column C30: third distillation column

D10: crystallization and solid-liquid separator

Detailed Description

The above and other objects of the present invention will be better understood from the following description of the invention, the accompanying drawings and the appended claims.

However, the present invention is not limited to the following examples, which are provided only for describing the present invention, but is defined only by the claims, but various embodiments.

The present invention will be described in detail below.

The method of the invention has the following advantages: by reacting a mixture comprising an aromatic compound, a diiodized aromatic compound or water, and iodine (I) in the presence of a zeolite catalyst and oxygen₂) The temperature of an iodinating reactor can be stably and reliably controlled, thereby improving productivity of iodinating aromatic compounds per unit weight of a catalyst and suppressing side reactions forming impurities.

In addition, since the embodiment of the present invention also includes multi-step distillation, crystallization and solid-liquid separation, the diiodoated aromatic compound obtained by the process of the present invention can be recycled.

The "aromatic compound" of the present invention is defined as a non-halogenated aromatic compound such as benzene, naphthalene and biphenyl, and the "monoiodinated aromatic compound" or "monoiodinated compound" is defined as an aromatic compound in which one hydrogen atom of the aromatic compound is substituted with an iodine atom, such as benzene monoiodide.

Further, "diiodinated aromatic compound" or "diiodinated compound" is defined as an aromatic compound in which any two hydrogen atoms of the aromatic compound are substituted with iodine atoms, such as diiodized benzene. In addition, the diiodoated aromatic compound has three isomers, i.e., a p-diiodoated aromatic compound, an o-diiodoated aromatic compound and an m-diiodoated aromatic compound. In addition, "iodinated aromatic compounds" prepared in the present invention are defined as aromatic compounds in which one or more hydrogen atoms of the aromatic compound are substituted with iodine atoms, and include monoiodinated aromatic compounds, diiodinated aromatic compounds, and triiodinated aromatic compounds.

Further, the "iodination" of the present invention is defined as the reaction of an aromatic compound such as benzene and naphthalene with iodine (I)₂) By substituting a hydrogen atom of the aromatic compound with an iodine atom. By the iodination, monoiodinated aromatic compounds and polyiodinated aromatic compounds such as diiodinated aromatic compounds and triiodinated aromatic compounds can be obtained.

Referring to fig. 2, the preparation method of the present invention has the following advantages: by reacting a mixture comprising an aromatic compound, a diiodized aromatic compound or water, and iodine (I) in the presence of a zeolite catalyst and oxygen₂) The temperature of the iodinating reactor can be stably and reliably controlled, thereby improving the productivity of iodinated aromatic compounds.

One embodiment of the present invention relates to a method for preparing an iodinated aromatic compound, comprising:

comprising an aromatic compound, a diiodized aromatic compound or water, and iodine (I) in the presence of a zeolite catalyst and oxygen₂) Iodinating the mixture of (1).

That is, according to the above embodiment of the present invention, by adding a diiodized aromatic compoundAn aromatic compound which is iodine (I)₂) Iodinated objects — side reactions caused by iodinated aromatic compounds such as mono-iodinated aromatic compounds and di-iodinated aromatic compounds can be suppressed, so that the temperature of the iodinating reactor can be stably and reliably controlled. In addition, by suppressing side reactions of iodinated aromatic compounds such as the mono-iodinated aromatic compound and the di-iodinated aromatic compound, productivity of the iodinated aromatic compound (particularly, the di-iodinated aromatic compound) and selectivity to the di-iodinated aromatic compound, which are commercially valuable, can be significantly increased.

According to an example of the above embodiment of the present invention, iodine (I) is used by adding water to an aromatic compound₂) The subject of iodination — can reliably control the oxidation reaction (violent exothermic reaction) of hydrogen iodide, and thus can stably and reliably control the temperature of the iodinating reactor.

Thus, by adding the diiodoated aromatic compound or water to the aromatic compound, which is iodine (I), according to any of the embodiments of the present invention₂) The object of iodination- -can keep the productivity of the diiodized aromatic compound and the selectivity to the diiodized aromatic compound at a high level. In addition, the temperature of the iodinating reactor can be stably and reliably controlled, and thus the feed rate of the reactants can be increased, thereby increasing the productivity of the commercially valuable p-diiodoated aromatic compound.

As a general rule, iodination of aromatic compounds in the presence of zeolite catalysts is accompanied by adsorption and desorption of reactants and products. Specifically, the reactant is adsorbed on a zeolite catalyst and then desorbed in the form of an iodinated aromatic compound after iodination. On average, the adsorption/desorption is more vigorous in the upper part of the iodinating reactor. Therefore, the reaction heat is locally released, and thus the local temperature of the reactor is high. However, according to the present invention, the adsorption/desorption is uniformly performed throughout the entire reactor, and thus it is possible to stably and reliably control the temperature of the iodinating reactor and to suppress side reactions due to an increase in temperature.

In addition, the present invention can minimize the generation of carbon dioxide and carbon deposits, so that the period of zeolite catalyst replacement can be extended. In addition, the present invention can improve the productivity of iodinated aromatic compounds, which are commercially valuable.

In the iodination of the above embodiment of the present invention, the presence of oxygen is essential. The hydrogen iodide formed in the iodination reaction should be oxidized to iodine (I)₂) To take part in the iodination reaction again. Therefore, when oxygen is not present or only a small amount of oxygen is present relative to hydrogen iodide, hydrogen iodide constitutes a conventional ratio with water produced in the oxidation reaction, has a harmful effect on the refining process, and may corrode equipment through a strong oxidation reaction.

The back pressure regulator shown in fig. 2 controls the iodination reaction pressure and allows a pressurized reaction. The sample processing system shown in fig. 2 removes vapor included in the gas to protect the gas analyzer. In addition, the gas analyzer may be used to analyze the concentration of carbon dioxide in a gas.

The zeolite catalyst of the present invention may be selected from the group consisting of Y-type zeolite, ZSM5 zeolite and K-13X zeolite, but is not limited thereto, and preferably may be Na-13X zeolite.

Further, the aromatic compound of the present invention may preferably be selected from benzene, naphthalene and biphenyl, and the diiodoated aromatic compound of the present invention may preferably be selected from diiodobenzene, diiodonaphthalene and diiodobiphenyl.

The aromatic compound and iodine (I)₂) The molar ratio of (b) may vary depending on the reaction conditions. If a large amount of iodine (I) is used₂) When iodine (I) is present₂) The productivity of the polyiodinated aromatic compound increases when the conversion of (a) is low. However, if iodine (I) is increased₂) Conversion of (A) to iodine (I)₂) For a large amount of aromatic compounds, iodine (I) can be increased₂) But reduces the di-iodinated aromatic compoundThe productivity of the product. Therefore, the aromatic compound may be reacted with iodine (I) in consideration of the purpose of the iodination₂) The molar ratio of (b) is appropriately controlled, and it is preferably used in a molar ratio (aromatic compound/iodine) of 0.3 to 3.0.

The diiodinated aromatic compound may be used in a molar ratio of 2 to 10mol% with respect to the aromatic compound, and water may be used in a molar ratio of 5 to 30mol% with respect to the aromatic compound.

Further, the water may be tap water or distilled water, but is not limited thereto.

According to the temperature profile of the iodination reaction of one embodiment of the present invention, the higher the reaction temperature is adjusted, the higher the conversion of the reactants (aromatic compound and iodine) and the lower the selectivity of the commercially valuable to the diiodinated aromatic compound. In addition, the pressure of the reaction can be adjusted within various pressure ranges. The pressure of the reaction is adjusted to be high, and the efficiency of the iodination reaction can be improved. From the above, the iodination reaction may preferably be carried out at 230-350 ℃ and under normal pressure to 5 atmospheres.

In addition, the diiodinated aromatic compound may be obtained according to a general preparation method or by commercial purchase, but is not limited thereto. Also, it may be preferable according to another embodiment of the present invention that further comprises a plurality of steps such as distillation, recrystallization and solid-liquid separation from the reactants to be the aromatic compound, the diiodized aromatic compound or water, and iodine (I)₂) Is obtained as a reaction product of the iodination reaction of (1). In addition, the diiodoated aromatic compound includes three isomers, i.e., a p-diiodoated aromatic compound, an o-diiodoated aromatic compound and an m-diiodoated aromatic compound.

Referring to fig. 3, a preferred embodiment of the manufacturing process further includes a process for recycling the diiodoated aromatic compound, which may include:

will consist of the aromatic compoundThe diiodized aromatic compound or water, and iodine (I)₂) The iodinated product obtained from the mixture is transferred from the iodinating reactor (R01) to a first distillation column (C10), and then the aromatic compound and water are separated and recovered from the iodinated product at the top of the first distillation column (C10);

the distillate at the bottom of the first distillation column (C10) was sent to a second distillation column (C20), and then the monoiodinated aromatic compound and iodine (I) were separated and recovered from the distillate at the top of the second distillation column (C20)₂)；

Transferring the distillate from the bottom of the second distillation column (C20) to a third distillation column (C30), and then separating and recovering di-iodo aromatic compounds including p-di-iodo aromatic compounds, o-di-iodo aromatic compounds, and m-di-iodo aromatic compounds from the distillate at the top of the third distillation column (C30) and transferring them to a crystallization and solid-liquid separator (D10);

separating and recovering the solid-phase p-diiodinated aromatic compound and a mother liquor comprising the liquid-phase p-diiodinated aromatic compound, o-diiodinated aromatic compound and m-diiodinated aromatic compound from the crystallization and solid-liquid separator (D10); and

recycling the diiodized aromatic compound by feeding a portion of the mother liquor to an iodinating reactor (R01).

The melting points of the p-diiodobenzene, the m-diiodobenzene and the o-diiodobenzene are 131 ℃, 36 ℃ and 27 ℃ respectively. Therefore, according to one embodiment of the present invention, the diiodobenzene obtained from the top of the third distillation column (C30) exists as a liquid and solid mixture (eutectic mixture) at normal temperature (25 ℃). Specifically, after recrystallization and separation, a mother liquor containing 15.4% p-diiodobenzene, 71.5% m-diiodobenzene and 15.4% o-diiodobenzene can be separated from pure solid p-diiodobenzene. It can be seen that the three isomers (p-, m-, o-) form a eutectic mixture at a temperature lower than the melting points of the three isomers, and thus can exist in a liquid form at normal temperature. One object of the present invention can be solved by recycling the diiodobenzene in the above mother liquor to the iodinating reactor (R01).

Further, fig. 4 is a detailed view of the iodinating reactor (R01) shown in fig. 2 and 3. Fig. 4 shows in particular the catalyst bed inside the iodinating reactor (R01), and a movable thermocouple. The zeolite catalyst was packed inside the iodinating reactor (R01) and surrounded by a catalyst bed support and an oil jacket. In addition, a movable thermocouple was incorporated inside the catalyst bed, as shown in FIG. 4. In order to maintain the reaction temperature constant, oil may be supplied from the lower part of the oil jacket, and the oil absorbs high heat in the iodination reaction and is recycled to the upper part of the oil jacket and then recovered from the upper part of the oil jacket. As described above, by circulating and recovering oil with the oil jacket, the temperature of the iodinating reactor can be stably and reliably controlled.

The present invention is further illustrated in detail with reference to the following examples. However, these examples should not be construed as limiting the scope of the invention in any way.

The terms used in the comparative examples and examples to demonstrate the utility of the present invention are given below.

First, the "aromatic/I" ratio describes the molar ratio of aromatic compound and iodine used. Specifically, to prepare the diiodobenzene, the benzene should be mixed with 1 mole of iodine (two iodine atoms, I)₂) And (4) reacting. Thus, the aromatic/I is defined as in the following equation 1.

[ EQUATION 1 ]

aromatic/I ═ [ (moles of benzene x 2) + (moles of benzene monoiodide)]Iodine (I)₂)×2

Further, terms used to prove the utility of the reaction products and methods are as follows. First, the productivity of p-DIB is defined as the amount of p-DIB produced per unit time and unit volume of catalyst. The units are expressed in g/l.h. Iodine (I)₂) And the conversion of benzene is defined as the converted iodine (I)₂) Or the amount of benzene and iodine (I)₂) Or the amount of benzene, expressed as a percentage (%).

Iodinated benzene produced by the iodination reaction includes monoiodinated benzene (MIB), Diiodobenzene (DIB) and triiodinated benzene (TIB), which have three isomers, respectively. Specifically, DIB includes three isomers of p-diiodobenzene (p-DIB), o-diiodobenzene (o-DIB), and m-diiodobenzene (m-DIB). In addition, "total DIB" can be defined as the total weight percentage of p-DIB, o-DIB, and m-DIB produced relative to the product, as shown in equation 2 below.

[ equation 2 ]

Total DIB ═ p-DIB + m-DIB + o-DIB)/(product) × 100

In addition, the selectivity can be defined as the weight percentage of p-DIB relative to the three DIB produced, as shown in equation 3 below.

[ equation 3 ]

Selectivity ═ p-DIB)/(p-DIB + m-DIB + o-DIB) × 100

According to the present invention, para-diiodoated aromatic compounds of high commercial value, which can be derived from high "total DIB" and "selectivity to p-DIB", can be efficiently produced.

Comparative example 1

The iodinating reactor shown in FIG. 1 was used, without adding DIB, with benzene (176.4g/h) and iodine (I)₂) (275.0g/h) and air. Iodine (I)₂) And air passed through a preheater and heated to 200 c, and then supplied to the iodinating reactor (R01). In addition, benzene was also heated to 200 ℃ and fed as steam using other feed lines. The reaction temperature of the iodinating reactor was controlled by controlling the temperature of the oil supplied to the oil jacket. The temperature of the iodinating reactor measured at the inner center of the iodinating reactor was adjusted to be kept constant at 280 ℃. But the reaction temperature is not kept constant. The temperature of the upper portion of the iodinating reactor is higher than the ideal temperature. And, the temperature of the iodinating reactor is decreased along the flowing direction of the reactants. To examine the temperature profile of the iodinating reactor, temperature measuring devices such as a thermowell and a thermocoupleIs arranged in the inner center of the iodinating reactor. The temperatures of the upper, middle and lower portions of the iodinating reactor were then periodically measured using movable thermocouples, which were movable upward and downward in the iodinating reactor, to determine the highest temperature region. After the reaction conditions were reached, the reaction was allowed to proceed at room temperature for 24 hours. Then, sampling and analysis were performed after the iodination, and the reaction conditions and results are shown in the following table 1.

Comparative example 2

In addition to benzene and iodine (I)₂) Except for 265.2g/h and 412.5g/h, respectively, all reaction conditions were adjusted to be the same as in comparative example 1. In comparative example 2, the reaction temperature could not be controlled stably and reliably. That is, the upper temperature of the iodinating reactor was increased to 380 ℃ or more, and thus the reaction was terminated. When the reaction temperature is higher than the above temperature, a large runaway reaction of benzene occurs, which in turn leads to a large deposition of carbon compounds.

Example 1

The iodinating reactor shown in FIG. 2 was used except that benzene (565.2g/h), diiodobenzene (83.4g/h) and iodine (I)₂) (900.1g/h) was fed to the iodinating reactor, and all the reaction conditions were adjusted to be the same as in comparative example 1. The reaction conditions and the reaction results are shown in table 1 below. The DIB used was obtained from a mother liquor of the three isomers (para, ortho and meta) separated from the pure p-DIB crystalline solid.

Example 2

In addition to benzene, water and iodine (I)₂) Except for the feeds of 550.0g/h, 35g/h and 744.1g/h, respectively, all reaction conditions were adjusted to be the same as in comparative example 1. The reaction conditions and the reaction results are shown in table 1 below.

[ TABLE 1 ]

		Comparative example 1	Comparative example 2	Example 1	Example 2
						Benzene and its derivatives	g/h	176.4	265.2	565.2	550.0
Iodine	g/h	275.0	412.5	900.1	744.1
						aromatic/I	Molar ratio of	2.08	2.09	2.04	2.40
DIB	g/h	0	0	83.4	0
						Water (H)2O)	g/h	0	0	0	35
Benzene and its derivatives	By weight%	14.96		12.56	16.71
						MIB	By weight%	50.40		40.99	45.31
p-DIB	By weight%	22.33		30.69	22.06
						m-DIB	By weight%	5.76		4.88	5.59
o-DIB	By weight%	1.12		1.45	1.86
						TIB	By weight%	1.72		2.13	3.22
productivity of p-DIB	g/l·h	13.80		64.24	40.74
						I2Conversion rate of (2)	％	97.64		94.84	97.81
Conversion of benzene	％	63.33		67.44	60.64
						Total DIB	By weight%	30.33		39.93	31.14
Selectivity of p-DIB	％	76.45		82.90	74.75
						Carbon deposit	g/kg	0.78		0.64	0.59
CO2	％	2.33		1.07	0.98

Total DIB, p-DIB Selectivity and inverse as shown in Table 1The conversion of the reaction was hardly different between the comparative example and the example. As described above, as iodine (I)₂) The other reactants, comparative example 1 used only benzene, example 1 used benzene and DIB, and example 2 used benzene and water. Although the total DIB, selectivity and conversion were almost the same for the comparative examples and examples, the productivity of p-DIB was much higher for the examples than for the comparative examples. Specifically, the productivity of p-DIB in example 1 or 2 was 3 times higher than that in comparative example 1. This may be caused by control of the temperature of the iodinating reactor. To increase the productivity of p-DIB, the input rate of the feed reactants should be increased. However, as shown in the reaction results of comparative example 2, in the case where the reactants were benzene and iodine alone, when the feed flow rate of the reactants was increased, the temperature of the upper portion of the iodinating reactor could be uncontrollably increased. According to the temperature profile in comparative example 1, the upper temperature of the iodinating reactor was 40 ℃ higher than the central temperature. Furthermore, consider CO₂And the amount of carbon deposits, examples 1 and 2 are superior to comparative examples 1 and 2. This is caused by the temperature control of the iodinating reactor.

Thus, by using a zeolite catalyst and oxygen to make a catalyst comprising an aromatic compound, a di-iodo aromatic compound or water, and iodine (I)₂) The preparation method of the present invention facilitates control of the temperature of an iodinating reactor, thereby increasing the productivity of iodinated aromatic compounds per unit weight of catalyst and improving the production of DIB, especially p-DIB. Therefore, the preparation method of the present invention can be widely and effectively used for the production of the iodinated aromatic compounds.

Claims (6)

1. A process for preparing iodinated aromatic compounds comprising:

comprising an aromatic compound, a diiodized aromatic compound or water, and iodine (I) in the presence of a zeolite catalyst and oxygen₂) The mixture of (a) is iodinated,

wherein the diiodinated aromatic compound is used in a molar ratio of 2 to 10mol% with respect to the aromatic compound,

the water is used in a molar ratio of 5 to 30mol% with respect to the aromatic compound,

the iodination reaction is carried out at 230-350 ℃ and under normal pressure to 5 atmospheric pressures, and

wherein the aromatic compound is selected from the group consisting of benzene, naphthalene and biphenyl.

2. The method of claim 1, wherein the diiodized aromatic compound is selected from the group consisting of diiodized benzene, diiodized naphthalene, and diiodized biphenyl.

3. The process of claim 1 wherein the zeolite catalyst is selected from the group consisting of Na-13X zeolite, Y zeolite, ZSM5 zeolite, and K-13X zeolite.

4. The process of claim 3 wherein the zeolite catalyst is a Na-13X zeolite.

5. The method of claim 1, further comprising:

recycling a di-iodo aromatic compound comprising a p-di-iodo aromatic compound, an o-di-iodo aromatic compound and a m-di-iodo aromatic compound,

wherein the diiodoated aromatic compound is obtained by:

distilling the mixture of the aromatic compound, the diiodoated aromatic compound or water, and iodine (I)₂) The mixture obtained was subjected to iodination, and the distillate was subjected to crystallization and solid-liquid separation.

6. The method of claim 5, further comprising:

will consist of said aromatic compound, said diiodoated aromatic compound or water, and iodine (I)₂) The resultant iodinated product obtained from the mixture was transferred from the iodinating reactor (R01) to a first distillation column (C10), and then the aromatic compound and water were separated and recovered from the iodinated product at the top of the first distillation column (C10);

transferring the distillate from the bottom of the first distillation column (C10) to a second distillation column (C20), and then separating and recovering monoiodinated aromatic compounds and iodine from the distillate at the top of the second distillation column (C20);

transferring the distillate from the bottom of the second distillation column (C20) to a third distillation column (C30), and then separating and recovering di-iodo aromatic compounds including p-di-iodo aromatic compounds, o-di-iodo aromatic compounds, and m-di-iodo aromatic compounds from the distillate at the top of the third distillation column (C30), and then transferring them to a crystallization and solid-liquid separator (D10);

separating and recovering the solid-phase p-diiodinated aromatic compound and a mother liquor comprising the liquid-phase p-diiodinated aromatic compound, o-diiodinated aromatic compound and m-diiodinated aromatic compound from the crystallization and solid-liquid separator (D10); and

recycling the diiodized aromatic compound by feeding a portion of the mother liquor to an iodinating reactor (R01).