WO2019039759A1 - Method for producing mono-iodobenzene and mono-iodobenzene produced therefrom - Google Patents

Abstract

The present invention relates to a process for producing mono-iodobenzene and mono-iodobenzene produced therefrom, the process selectively recovering gaseous iodine lost during regeneration of a catalyst used in a reaction, and allows to achieve an improved treatment efficiency by facilitating the implementation of the reaction by recovered iodine and the regenerated catalyst.

Description

 DESCRIPTION OF THE INVENTION

 Title of the Invention

 Process for producing mono-iodobenzene and mono-iodobenzene prepared therefrom [Technical Field]

 The present invention relates to a process for the preparation of mono-iodobenzene and mono-iodobenzene prepared therefrom. More specifically, it is possible to selectively recover gaseous iodine which is lost in the regeneration of the catalyst used in the reaction, and to recover mono-iodine, which improves process efficiency by recovering iodine and regenerated catalyst, Benzene and mono-iodobenzene prepared therefrom.

 TECHNICAL BACKGROUND OF THE INVENTION

 Exhaust gas discharged during regeneration of the poisoned catalyst in the heterogeneous catalytic converter is usually neutralized with caustic soda through a scrubber. When the exhaust gas containing halogens is neutralized with caustic soda in a scrubber, the halogens are counteracted with caustic soda and present as salts in aqueous solution. In order to recover or separate halide halogen elements, acid treatment is required, and a large amount of wastewater is generated.

In particular, the exhaust gas discharged during the catalyst regeneration contains a large amount of C0 / C0 ₂ generated by burning of the hydrocarbon material present in within the coke coming from the poisoning of the catalyst. A large amount of C0 / C0 ₂ is also in the scrubber and banung caust ic soda and produce a NaHC0 _3, NaHC0 ₃ high solubility in water is present in a saturated state in the aqueous solution. When a neutralization treatment using an acid for recovering a halogen element is performed, a large amount of acid is also consumed in the neutralization of NaHCO ₃ , and thus a large amount of wastewater is generated.

The catalyst used in the chemical banung of material containing iodine after poisoning, the elemental iodine upon reproduction is discharged in gaseous form together with C0 / C0 _2. In a chemical process involving the reaction of a substance containing a halogen element, it is necessary to recover or separate halogens released in exchange for wastewater in relation to the relatively high price of halogen element and air / soil contamination. The recovery and separation techniques of halogens, which are known until now, Can, in addition there is a limited number of drink group of a halogen element present in a low concentration of the liquid phase within several hundred p _pm.

 Halogen recovery and separation techniques of known gaseous state are methods of neutralization using caust ic soda, which generate large amounts of wastewater. In addition, the method of recovering halogen elements in the gaseous state, which has been known so far, is limited to the separation of air containing low-concentration halogen elements, not the recovery of halogen elements from the waste gas.

 Therefore, it is necessary to develop a technique for selectively separating and recovering iodine at a high concentration from the syngas, and reusing the recovered iodine in the iodide compound reaction.

 DISCLOSURE OF THE INVENTION

 [Problem to be solved]

 The present invention relates to a process for the production of mono-iodobenzene which can selectively recover gaseous iodine which is lost during the regeneration of the catalyst used in the reaction, and which proceeds by using recovered iodine and regenerated catalyst, The method is intended to provide three days.

 The present invention also provides mono-iodobenzene prepared from the process for producing mono-iodobenzene.

 MEANS FOR SOLVING THE PROBLEMS

(1) preparing mono-iodobenzene from a reaction product comprising at least one multi-iodinated benzene and benzene selected from the group consisting of di-iodobenzene and tri-iodobenzene in the presence of a zeolite catalyst, ; (2) calcining the deactivated zeolite catalyst at a temperature of 400 ^° C to 650 ^° C after the mono-iodobenzene preparation step; (3) adsorbing a gaseous impurity containing iodine and carbon oxides generated in the firing step on activated carbon; (4) desorbing the carbon oxide by raising the activated carbon from 20 ^° C to 90 ^° C; (5) desorbing iodine by raising the activated carbon from 90 ^° C to 450 ^° C; And (6) recovering the desorbed iodine.

In this specification, also, by the method for producing mono-iodobenzene The resulting mono-iodobenzene is provided.

The process for preparing mono-iodobenzene according to a specific embodiment of the present invention and the mono-iodobenzene prepared therefrom will now be described in more detail. It is to be understood that when an element is referred to as being "comprising" an element herein, it is meant to include other elements, (1) reacting, in the presence of a zeolite catalyst, a reactant comprising at least one multi-iodinated benzene and benzene selected from the group consisting of di-iodobenzene and tri-iodobenzene, with mono-iodobenzene (2) firing the deactivated catalyst at a temperature of 400 V to 650 ^° C after the mono-iodobenzene preparation step, (3) (4) desorbing the carbon oxides by raising the temperature of the activated carbon from 20 ^° C to 90 ^° C; (5) a step of raising the temperature of the activated carbon from 90 ^° C to 450 ^° C to desorb iodine, and (6) recovering the desorbed iodine. The present inventors have found that, by using the above-described method for producing mono-iodobenzene, it is possible to adsorb an iodine gas in a relatively high amount of activated carbon among gaseous impurities generated in the regeneration process of an inactive catalyst, Iodine and carbon oxides, iodine can be selectively desorbed and recovered, thereby being reused in the initial reaction of mono-iodobenzene synthesis.

 Specifically, since poisoning through the reaction can recover iodine, which remains in the reactor during the regeneration of the inactive catalyst, the mono-iodobenzene synthesis reaction process is carried out using the regenerated catalyst and recovered iodine It is possible to realize high efficiency in the process because it can proceed again.

Particularly, a high ratio from a gas mixture of gaseous iodine and carbon oxide It seems that the adsorption of iodine is due to the action of activated carbon on gaseous iodine and the ability to selectively desorb iodine from adsorbed iodine and carbon oxides through a simple process of controlling the temperature- It seems to be due to the difference in desorption rate between iodine and carbon oxides depending on the temperature of the snow.

 Hereinafter, the method for producing mono-iodobenzene according to one embodiment will be described in detail.

(1) preparing mono-iodobenzene from a reaction product comprising at least one multi-iodinated benzene and benzene selected from the group consisting of di-iodobenzene and tri-iodobenzene in the presence of a light catalyst,

 Wherein the zeolite catalyst is a zeolite catalyst for use in a trans-iodination reaction from a reaction product comprising multi-iodinated benzene and benzene, wherein the catalyst is a catalyst in which the molar ratio of Si / Al is 5 to 100, 50% is ion exchanged with an alkali metal or an alkaline earth metal.

In the present invention, 'multi-iodinated benzene' refers to benzene in which at least one hydrogen of benzene such as mono-iodobenzene, di-iodobenzene, and tri-iodobenzene is substituted with iodine. In the present invention, the term "trans-iodide counter-attack" refers to a reaction involving intramolecular movement (isomerization) or intermolecular movement of iodine atoms contained in a molecule, and polyphenyl sulfide iodo benzene (MIB) and p-di-iodo benzene (p-DIB), which are used as raw materials for the synthesis of poly (phenylene sulfide) And can be very usefully used for manufacturing. In order to effectively produce p-DIB, which is the main raw material of PPS, from benzene and iodine, the oxyiodination reaction and the trans-iodination reaction must be combined and include the same process as proposed in the countermeasure scheme shown in FIG. 1 . 1, p-DIB is prepared from benzene and iodine via an oxiodidation counter mass, and benzene and MIB are recovered to the oxy-iodinated semi-annular phase through distillation among the produced sub- (M-di-iodo benzene, m-DIB), o-di-iodobenzene benzene, o-DIB) and tri-iodo benzene (TIB) are separated by crystallization and then sent to the trans-iodobarbital period and then converted to MIB and sent to the oxyiodide hector . When the process is configured as described above, even if the hydrocarbons such as m-DIB, o-DIB, and TIB are generated, they can be effectively recovered and reused without loss of iodine.

 At the core of the process proposed in the present invention is the oxo-iodination reaction and the trans-iodination reaction, in particular the trans-iodination reaction using m-DIB, o-DIB 맟 TIB, which are by-products of the oxyiodination reaction. The loss of aromatics iodide compounds in these two antagonists has a critical impact on economic viability. Therefore, it is necessary to study the oxiodination reaction and the trans iodination reaction which can minimize the loss of iodine. As the catalyst suitable for this reaction, the cation exchange zeolite catalyst according to the above embodiment can be used.

 The zeolite catalyst can be used to prepare MIB and P-DIB through the trans-iodobenzene, preferably MIB. Particularly, the zeolite catalyst increases the selectivity to mono-iodobenzene in the trans-iodination reaction and alleviates the deactivation of the catalyst even when it is used for a long time, thereby improving the lifetime of the catalyst.

At this time, the Si / Al molar ratio of the zeolite catalyst may be suitably in the range of 5 to 15. A Si / Al molar ratio in the range of 5 to 15 is advantageous for maintaining a high trans ionization reaction activity of the catalyst. The alkali metal or alkaline earth metal used for the cation exchange may be selected without limitation of its constitution, but preferably it can be exchanged with sodium (Na) or potassium (K). The degree of the cation exchange can be determined depending on the type of the alkali metal or alkaline earth metal cation to be exchanged within the range of 2% to 50% of the total ion exchange capacity. Preferably 20% to 50% of the total ion exchange capacity when cation exchange is performed with sodium (Na) ion, and when cation exchange is performed with potassium (K) ion, the total ion exchange capacity 10% to 50% is preferable. When the trans-iodination reaction proceeds using a cation-exchanged catalyst within the above range, the degree of selectivity of mono-iodobenzene is high and the phenomenon of catalyst deactivation is small. this When the ion exchange capacity of the cation component is less than 2%, the catalytic activity effect can not be obtained. When the ion exchange capacity exceeds 50%, the acid site of the catalyst is excessively reduced and the activity of the trans- have. The specific conditions and methods for the cation exchange reaction using the alkali metal or alkaline earth metal can be used without any limitation in the extent known to be applicable to the ion exchange reaction of the zeolite catalyst.

On the other hand, the catalyst which can be used for preparing the cation-exchange zeolite can be selected from cation exchange from any one selected from the group consisting of Y, BEA, and ZSM-5 agents by cation exchange with an alkali metal or an alkaline earth metal have. Catalysts used in the preparation of cation-exchange zeolites are characterized by acid strength and pore structure as solid-phase acid catalysts. The strong acidity of the zeolite catalyst occurs when ammonium ions are exchanged and then fired to convert to hydrogen ions. Typical zeolite catalysts include Y, BEA, ZSM-5, and Mordeni te. They can be used to exchange or support ions with transition metals, rare earth metals, alkali metals, and alkaline earth metals to control acidity and pore size. have. In order to produce the catalyst according to the embodiment of the present invention, it is preferable to perform cation exchange using H ⁺ -type zeolite ion-exchanged with hydrogen ions, and it is preferable to use a zeolite catalyst such as HY, HBEA or HZSM- Can be used.

 In the preparation of the mono-iodobenzene according to this embodiment, the addition of benzene to the reactant mullite-iodide benzene has a positive effect on the selectivity of the MIB and the inactivation of the catalyst. In particular, it plays a decisive role in reducing the rate of deactivation of the catalyst. The effect of reducing the deactivation rate of the catalyst and the selectivity of the MIB was observed to be larger as the amount of benzene contained in the reactant increased.

Therefore, in order to increase the selectivity of the MIB produced through the trans-iodination reaction and to prevent the deactivation of the catalyst, it is preferable that the molar ratio of benzene / multi-iodide benzene is 2: 1 or more. In order to selectively obtain the MIB, More preferably, the molar ratio of the multi-iodinated benzene is 3: 1 or more, For sufficient supply of iodine, the molar ratio of benzene / multi-iodide benzene is preferably 25: 1 or less. Thus, the addition of benzene to the reaction mixture plays a crucial role in obtaining stable MIB from the multi-iodinated benzene. In the trans-iodination reaction, the remaining process conditions except for the selection of the catalyst and the reactant are not particularly limited, but the trans-iodination reaction may be considered to have a greater importance of the reaction temperature than the other reaction products. However, the initial selectivity of MIB may decrease if the temperature of the catalyst is excessively high. In this case, the initial selectivity of the MIB may be lowered. There is a need to optimize the anti-air temperature. Therefore, it is preferable that the trans-iodination reaction of the present invention is carried out at a degree of silver of 120 ^° C to 250 ^° C for maintaining the selectivity and catalytic activity of the MIB, and the reaction ^at a temperature of 160 ^° C to 200 ^° C desirable.

In addition, the repulsive pressure is also an important parameter in terms of catalyst deactivation as well as the reaction temperature. It is desirable to keep the reaction pressure below a certain pressure. That is, it is highly desirable that the benzene contained in the water is kept at a pressure lower than a pressure that can exist in a gas phase, not a liquid phase. If the pressure is higher than this range, the deactivation of the catalyst may proceed more rapidly. Therefore, it is desirable to maintain the atmospheric pressure of about atmospheric pressure within the range of 120 ^° C to 250 ^° C, In view of prevention of deactivation of the catalyst which maintains the unreasonable pressure at 10 atm or less, which is a possible pressure.

(2) calcining the deactivated zeolite catalyst after the mono-iodobenzene preparation step at a temperature of 400 1 C to 650 X

 When the trans-iodination reaction is performed for a long time in the mono-iodobenzene production step, the activity of antimony and the selectivity of MIB decrease after a lapse of a certain period of time.

It is interpreted that the deterioration of the catalyst performance is attributed to the deposition of coke, and it is interpreted that if the amount of deposition exceeds a certain amount, the activity is rapidly deteriorated. It is difficult to fundamentally prevent coke deposition in the catalyst, Minimizing the rate is important to prolong catalyst life. When the catalytic activity is lowered by the coke deposition, it is preferable to reuse the catalyst after regeneration to remove the coke

At this time, the deactivated zeolite catalyst can be reused by calcining it at a temperature of 400 ^° C to 650 ^° C under oxygen or air atmosphere.

(3) adsorbing a gaseous impurity including iodine and carbon oxides generated in the firing step on activated carbon

 In the firing step, a gaseous iodine and a carbon oxide together with nitrogen are generated due to the combustion of a multibenzene ring compound, that is, a coke material, in which an iodine compound present in the catalyst repellant and an iodine ring present in the catalyst pore are connected to each other.

 Specifically, the gaseous impurities may comprise from 0.1 vol% to 10 vol% iodine gas, from 15 vol% to 24 vol% carbon oxide gas, and from 70 vol% to 80 vol% nitrogen gas.

These gaseous impurities move to the activated carbon column located at the rear end of the reactor and can be adsorbed by activated carbon layered in the activated carbon column. But are not the temperature and the pressure during the adsorption greatly limited, and examples thereof can be carried out at room temperature and pressure of 20 ^° C to 30 ^° C.

 On the other hand, when the content of the component adsorbed in the activated carbon is confirmed through TGA and ion chromatography (IC), iodine and carbon oxides can be adsorbed in an amount of 80 to 90 parts by weight based on 100 parts by weight of the activated carbon. That is, in the case of nitrogen which occupies the majority of the gaseous fugitives, the ratio of the adsorbed nitrogen to the activated carbon is very small, while the iodine and carbon oxides in the gaseous fugace are mostly adsorbed on the activated carbon.

 This is because activated carbon selectively has high adsorption power against iodine and carbon oxides, and it is possible to effectively recover an iodine compound that is easily lost in a gaseous state by the adsorption force of the activated carbon.

More specifically, the content of the carbon oxide adsorbed on the activated carbon relative to 100 parts by weight of iodine adsorbed on the activated carbon is 25 parts by weight or less, or 1 part by weight To 25 parts by weight. That is, when adsorbed by the activated carbon, iodine can be adsorbed at a high content through the highest adsorption force on the activated carbon. It can be confirmed from the fact that iodine occupying 0.1 to 10 volume% in the gaseous sludge shows a larger amount than carbon oxide in the amount of adsorption in the final active carbon.

 Therefore, iodine gas remaining in trace amounts can be effectively adsorbed on activated carbon through the step of adsorbing gaseous fractions using the activated carbon, so that the content of iodine lost can be minimized and the efficiency of the process can be increased. The carbon oxide is a compound formed by chemical bonding of carbon and oxygen, and may include, for example, carbon monoxide or carbon dioxide.

(4) the step of desorbing the carbon oxide by raising the activated carbon from 20 1 C to 90 TC

In the step of desorbing the carbon oxide by raising the temperature of the activated carbon from 20 ^° C to 90 ^° C, or from 20 ^° C to 80 ^° C, or from 50 ^° C to 90 ^° C, the carbon oxide is selectively desorbed from the activated carbon, And iodine is controlled to a temperature range capable of maintaining the state of being adsorbed on activated carbon. The example of the temperature raising method of the activated carbon is not limited to a wide range. For example, a method of heating the activated carbon column by heated nitrogen or external tracing can be used.

Specifically, in the step of desorbing the carbon oxide by raising the activated carbon from 20 ^° C to 90 ^° C, the iodine content desorbed from the activated carbon is less than 100 ppm, or 0.1 ppm to 50 ppm, or 1 ppm to 20 ppm Lt; / RTI > It is considered that some iodine is desorbed from activated carbon even at a temperature of 184 ^° C before the boiling point of iodine is due to the sublimation property of iodine.

The rate of iodine desorption according to the following formula 1 is less than 1 ¾, or 0.01% to 0.5%, or 0.05% to 0.2% when the temperature of the activated carbon is raised from 20 ^° C to 90 ^° C to desorb the carbon oxide .

 [Equation 1]

Iodine desorption (%) = desorbed iodine content (ppm) I adsorbed on activated carbon Chromium iodide content (ppm) x 100.

In the above Equation 1, the total iodine content (p _pm ) adsorbed on the activated carbon means the iodine ion content measured on the basis of 10000 g of the NaOH aqueous solution in which all the iodine adsorbed on the activated carbon has been collected, and the desorbed iodine content Means the iodine ion content measured on the basis of 1000 g of the aqueous NaOH solution desorbed from the step of desorbing carbon oxides by raising the temperature of the above-mentioned activated carbon from 20 ^° C to 90 ^° C.

On the other hand, in the step of desorbing the carbon oxide by raising the temperature of the activated carbon from 20 ^° C to 90 ^° C, the carbon oxide desorption rate according to the following formula 2 may be 95% or more, or 90% to 100%.

 &Quot; (2) "

 Carbon Oxide Desorption Rate (%) = Desorbed Carbon Oxide Content (ppm) I Total Carbon Oxide Content Absorbed in Activated Carbon (ppm) X 100.

In the above formula (2), the total carbon oxide content (ppm) adsorbed on the activated carbon means the NaHCO ₃ content measured on the basis of 1000 g of the NaOH aqueous solution in which all the carbon oxides adsorbed on the activated carbon have been collected, and the desorbed carbon oxide The content (ppm) means the content of NaHCO ₃ measured based on 1000 g of the aqueous NaOH solution desorbed from the step of desorbing the carbon oxide by raising the activated carbon from 20 ^° C to 90 ^° C.

In the step of raising the activated carbon from 20 ^° C to 90 ^° C to desorb the carbon oxide, the carbon oxide content desorbed from the activated carbon may be 1000 ppm or more, or 1000 ppm to 2000 ppm. Accordingly, in the step of raising the temperature from 20 ^° C to 90 ^° C to desorb the carbon oxide, the majority of the carbon oxides can be desorbed from the activated carbon and separated with high selectivity. Thus, in the step of raising the temperature of the activated carbon from 20 ^° C to 90 ^° C, the desorption rate of iodine and carbon oxide adsorbed on the activated carbon shows a remarkable difference. As a result, iodine is adsorbed on the activated carbon, Most of the oxides can be desorbed from the activated carbon to separate iodine and carbon oxides. The reason why the sublimable iodine is not desorbed even at 90 is that in order to desorb iodine adsorbed on the activated carbon, And it seems that it requires thermal energy higher than 90 ^° C. Thus, iodine and carbon oxides can be easily separated from the gaseous impurities in which iodine and carbon oxides are mixed only by a simple heating step, and only iodine can be recovered while satisfying the high yield and selectivity.

The method may further include neutralizing the desorbed carbon oxide after desorbing the carbon oxide by raising the activated carbon from 20 ^° C to 90 ^° C. The neutralization of the carbon oxide may be an alkali solution, for example, a sodium hydroxide solution. (5) a step of w by the activated carbon to from 90 ^"C 450 1C de-iodine complex

In the step of desorbing iodine by raising the activated carbon from 90 ^° C to 450 ^° C, or from 90 ^° C to 400 ^° C, or from 90 ^° C to 380 ^° C, the activated carbon is heated from 20 ^° C to 90 ^° C Iodine adsorbed on the activated carbon can be selectively desorbed through the step of desorbing the carbon oxide. Examples of the method for raising the temperature of the activated carbon are not particularly limited, and for example, a method of heating the active carbon column with heated nitrogen or external tracing may be used.

In the step of desorbing iodine by raising the temperature of the activated carbon from 90 ^° C to 450 ^° C, the iodine desorbed from the activated carbon may be 4000 ppm or more, or 4000 ppm to 7000 ppm. Accordingly, in the step of desorbing iodine by raising the temperature of the activated carbon from 90 ^° C to 450 ^° C, the majority of iodine can be desorbed from the activated carbon and separated with high selectivity.

The iodine desorption rate according to the following formula 3 may be 70% or more, or m> 10 or 70% to 80% in the step of desorbing iodine by raising the temperature of the activated carbon from 90 ^° C to 450 ^° C. have.

 &Quot; (3) "

 Iodine desorption (%) = desorbed iodine content (ppm) I total iodine adsorbed on activated carbon (ppm) X 100.

In the above equation (3), the total iodine content (ppm) adsorbed on the activated carbon is The iodine content (ppm) of the desorbed iodine is measured by removing the iodine from 90 ^° C to 450 ^° C by removing the iodine from the activated carbon, Means the iodine ion content measured on the basis of 10000 g of the aqueous NaOH solution in which the desorbed iodine is captured in the step.

In the step of desorbing iodine by raising the activated carbon from 90 ^° C to 450 ^° C, the carbon oxide content desorbed from the activated carbon may be less than 0.1 ppm. Accordingly, in the step of desorbing iodine by raising the temperature of the activated carbon from 90 ^° C to 450 ^° C, it can be confirmed that carbon oxides are hardly separated and discharged.

In the step of desorbing iodine by raising the temperature of the activated carbon from 90 ^° C to 450 ^° C, the desorption rate of carbon oxide by the following formula (4) is less than 1%, 0% to 0.5%, or 0% to 0.2% Lt; / RTI >

 &Quot; (4) "

 Carbon Oxide Desorption Rate (%) = Desorbed Carbon Oxide Content (ppm) I Total Carbon Oxide Content Absorbed in Activated Carbon (ppm) X 100.

In the above formula (4), the total carbon oxide content (ppm) adsorbed on the activated carbon means the NaHCO ₃ content measured on the basis of 1000 g of the NaOH aqueous solution in which all the carbon oxides adsorbed on the activated carbon have been collected, and the desorbed carbon oxide The content (ppm) was measured on the basis of 1000 g of NaOH aqueous solution in which carbon oxide desorbed in the step of desorbing iodine by raising the activated carbon from 90 ^° C to 450 ^° C

It means NaHC0 ₃ content.

Meanwhile, the step of desorbing iodine by raising the temperature of the activated carbon from 90 ^° C to 450 ^° C may be followed by a step of neutralizing desorbed iodine with an alkali solution. An example of the alkali solution is a sodium hydroxide solution.

(6) recovering the desorbed iodine

The desorbed iodine can be directly transferred to the reactor in which the initial reaction proceeds, or transferred to an iodine storage tank and stored. The above- Since iodine has a high purity through the above-mentioned two-step heating process, iodine can be directly applied to the reaction without a separate purification process.

 As described above, the method may further include neutralizing the desorbed iodine with an alkali solution before recovering desorbed iodine, if necessary. An example of the alkali solution is a sodium hydroxide solution. Specifically, the step of recovering the desorbed iodine may further include a step of reacting the recovered iodine with benzene to produce multi-iodinated benzene. Oxy iodide, which synthesizes benzene iodide with benzene and iodine as a starting material, proceeds slowly, so it can usually be carried out in liquid phase using nitric acid, acetic acid, hydrogen peroxide and silver sulfide as oxidizing agents.

 The multi-iodinated benzene obtained in the step of reacting the recovered iodine with benzene to produce multi-iodinated benzene may be used as a reactant for the step of preparing the mono-iodobenzene of step 1 described above. By effectively recovering iodine that is easily lost and reusing it as a reaction product, overall process efficiency can be improved. Meanwhile, according to another embodiment of the present invention, the mono-iodobenzene obtained by the process for producing mono-iodobenzene of the above embodiment can be provided. The process for preparing mono-iodobenzene may include all of the above-mentioned embodiments. In another embodiment, the mono-iodobenzene may be prepared by a process for preparing mono-iodobenzene of the above- .

 【Effects of the Invention】

 According to the present invention, it is possible to selectively recover gaseous iodine which is lost during the regeneration of the catalyst used in the reaction, and to recover the mono-iodobenzene And mono-iodobenzene prepared therefrom can be provided.

 BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a simplified illustration of the countercyclical behavior of the trans-iodinated counterpart according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

 The invention will be described in more detail in the following examples. It should be noted, however, that the following examples are illustrative of the present invention and are not intended to limit the scope of the present invention.

<Synthesis Example: Synthesis of Catalyst>

 Synthesis Examples 1 to 2: A cation / Na exchanger was added to a light catalyst

The Na-exchanged zeolite catalysts of Synthesis Examples 1 and 2 were prepared by ion exchange using 0.05N NaCl. Albemar le Y411 (Si / Al = 5.5) , respectively 20% of the zeolite catalyst (Example 1), 30% after one (Example 2) the ion-exchanged water in an amount more than 60 ^° C taking a 0.05N NaCl in distilled water to And washed. The above procedure was repeated once and then dried in an oven at 110 ^° C. Finally, the ion-exchanged catalyst was calcined at 550 ^° C in an air atmosphere to prepare a Na-exchanged zeolite catalyst. Synthesis Examples 3 to 4: cation / K-exchanged zeolite catalyst

The K exchanger of Synthesis Examples 3 and 4 was prepared by ion exchange with a light catalyst of 0.05N KNO ₃ . The amount of 0.05N KNO ₃ corresponding to 10% (Example 3) and 20% (Example 4) of each of the Albemar le Y411 (Si / Al = 5.5) zeolite catalysts was taken and ion-exchanged at 60 ^° C, And washed. The above procedure was repeated once and then dried in an oven at 110 1 :. Finally, the ion-exchanged catalyst was calcined at 550 ^° C in air atmosphere to prepare a K-exchanged zeolite catalyst.

&Lt; Example: Process for producing mono-iodobenzene >

 (1) Trans-iodination

 Using the zeolite catalysts prepared in Synthesis Examples 1 to 4, the trans iodination reaction was carried out under the following conditions.

 In order to prevent the occurrence of pressure loss and channeling of reactants during the reaction, a powdery catalyst was pressed into a press and used in the form of granules of 300 to 800 p in size.

Han Woonggi used a 3/4 "diameter stainless steel tubular barn, Fifty grams of the catalyst in the form of granules was added to the reaction chamber and reacted.

The catalyst was pretreated at 200 ^° C for 2 hours while flowing dry air at a flow rate of 200 ml / min. The feed rate of the reaction was 50 ml / h. The multi-iodinated benzene includes m-DIB and o-DIB as main components and partially contains MIB, p-DIB, and TIB. Respectively. At this time, the multi-iodinated benzene and benzene were used in a weight ratio of 3: 7 (the ratio of benzene / multi-iodide benzene was 16.5: 1) in the reaction product. Among the products used in this experiment, multi-iodinated benzene (hereinafter referred to as "feed") refers to residual components of MIB and p-DIB separated out from products produced by benzoin and iodine oxyiodide reaction. Under the above reaction conditions, 50 g of the catalysts of Synthesis Examples 1 to 4 were reacted at 250 ^° C and 1 atm under a pressure of 50 ml / hr. After a certain period of reaction, the poisoned catalyst was obtained.

 (2) Catalyst regeneration and iodine recovery

The reactor in which the target monomer of the above production example was placed was heated ^at 500 ^° C by a furnace outside the semi-wool machine, and air diluted with nitrogen was injected into the reactor to burn the target material. Thereafter, a gas mixture of iodine (about 0.3 volume 0, carbon monoxide (CO) / carbon dioxide (CO ₂ ) (about 24 vol ¾), water vapor (about 0.7 vol%), and nitrogen And then adsorbed on the activated carbon in the activated carbon column.

Then, the carbon monoxide (CO) or carbon dioxide (CO ₂ ) gas generated while raising the temperature of the activated carbon column from the upper to the 90 ^° C was treated with a scrubber located at the rear end of the activated carbon column, 25 ^° C, concentration: 2%, volume: 1000 ml).

Then, the temperature of the activated carbon column was raised from 90 ^° C to 380 ^° C, and the generated iodine gas was poured into a scrubber located at the rear end of the activated carbon column, and an aqueous solution of sodium hydroxide (temperature: 25 ^° C, concentration: 2%, Buffer: 1000 ml), and recovered. <Experimental Example> Experimental Example 1: Measurement of adsorption amount of activated carbon

 In the monomer-to-be-recycled process of the above example, the components adsorbed on activated carbon were measured by ion chromatography (IC) analysis, and the results are shown below.

 [Table 1]

Experimental Example 1 of Example

* ppm: iodide ion / NaHCO ₃ content in aqueous NaOH solution adsorbed iodine / carbon oxide

 As shown in Table 1, in the above example, the iodine gas and the carbon oxide gas generated in the regeneration process of the NOx adsorbent can be adsorbed using activated carbon, and in particular, it is confirmed that the adsorbent exhibits a better adsorbability against iodine gas . Experimental Example 2: Determination of iodine desorption content / desorption rate

 The amount (ppm) of desorbed iodine adsorbed on the activated carbon by the temperature rise of the activated carbon was measured in the target-repelling step of the above embodiment, and the results are shown in Table 2 below. The desorbed iodine content was measured by ion chromatography (IC) analysis on 1000 g of desorbed iodine-containing NaOH aqueous solution.

 The desorption rate of iodine according to the change of the activated carbon temperature was calculated through the following equation, and it is shown in Table 2 below.

 [Mathematical Expression]

 Iodine desorption (%) = Desorbed iodine content (ppm) I Total iodine adsorbed on activated carbon (ppm) 100.

[Table 2]

Experimental Example 2 of Example

* 350 (12 hours) refers to the period of temperature maintained for 12 hours immediately after reaching 350 ^° C.

 * ppm: iodine ion content in desorbed iodine-captured NaOH aqueous solution As shown in Table 2 above, in the above example, the iodine gas and the carbon oxide gas generated in the regeneration step of the adsorbent are adsorbed using activated carbon , Desorption can be performed by heating the activated carbon through heat treatment.

Particularly, iodine is not desorbed in the 50 to 80 ^° C section where most of the carbon oxides are desorbed (see Table 3 below), and most of the iodine is desorbed in the section of 80 ^° C or more, particularly 90 ^° C to 380 ^° C It can be confirmed that iodine and carbon oxides can be desorbed selectively. Experimental Example 3: Determination of carbon oxide desorption content / desorption rate

(Ppm) in which the carbon oxide adsorbed on the activated carbon, for example, carbon monoxide (CO) or carbon dioxide (CO ₂ ) is desorbed by the temperature rising section of the activated carbon, is measured in the target- Table 3 shows the results. The desorbed carbon monoxide (CO) or carbon dioxide (CO ₂ ) content is measured by means of an electrochromatography (IC) analysis on 1000 g of NaOH aqueous solution containing desorbed carbon monoxide (C 0) or carbon dioxide (CO ₂ ) Respectively.

The desorption rate of carbon monoxide (CO) or carbon dioxide (CO ₂ ) according to the change of activated carbon temperature was calculated by the following equation, and it is shown in Table 3 below.

 [Mathematical Expression]

Carbon Oxide Desorption Rate (%) = Desorbed Carbon Oxide Content (ppm) I Total carbon oxides content (ppm) X 100.

[Table 3]

Experimental Example 3 of Example

* 350 (12 hours) refers to the period of temperature maintained for 12 hours immediately after reaching 350 ^° C.

* ppm: NaHCO ₃ content in NaOH aqueous solution with desorbed carbon oxide. As shown in Table 3, the iodine gas and the carbon oxide gas generated in the regeneration step of the target monomer can be adsorbed using activated carbon, and desorbed through the heat treatment.

In particular, oxides of carbon has been most desorbed at 50 ~ 80 ^° C range, 80 - can be confirmed that the 90 ^"full is complete desorption in the C interval. In other words, desorption of the carbon oxides is completed in 50 - 90 ^° C range, 90 ^It can be seen that the carbon oxides are no longer desorbed in the range of ^° C to 380 ^° C. Since the desorption rates of iodine and carbon oxides adsorbed on activated carbon are different depending on the rising and falling sections, It can be confirmed that selective detachment is possible.

Claims

Claims:  [Claim 1]  Preparing mono-iodobenzene in the presence of a zeolite catalyst from a reactant comprising at least one multi-iodinated benzene and benzene selected from the group consisting of di-iodobenzene and tri-iodobenzene; Calcining the deactivated zeolite catalyst after the mono-iodobenzene preparation step ^at a temperature of 400 ^° C to 650 ^° C;  Adsorbing gaseous impurities including iodine and carbon oxides generated in the firing step on activated carbon; Desorbing carbon oxides by raising the activated carbon from 20 ^° C to 90 ^° C; Desorbing iodine by raising the temperature of the activated carbon from 90 ^° C to 450 ^° C; And  And recovering said desorbed iodine. &Lt; Desc / Clms Page number 19 &gt; [Claim 2]  The method according to claim 1, Iodobenzene having a iodine desorption ratio of less than 1% according to the following formula 1 in the step of raising the temperature of the activated carbon from 20 ^° C to 90 ^° C to desorb carbon oxides:  [Equation 1]  Iodine desorption (%) - Desorbed iodine content (ppm) I Total iodine adsorbed on activated carbon (ppm) X 100. [3]  In the above, Iodobenzene having a carbon oxide desorption ratio of 95% or more in the step of desorbing carbon oxides by raising the temperature of the activated carbon from 20 ^° C to 90 ^° C, &Quot; (2) &quot;  Carbon Oxide Desorption Rate (¾) = Desorbed Carbon Oxide Content (ppm) I Total Carbon Oxide Content Absorbed in Activated Carbon (ppm) X 100.  In Item 1, Iodine benzene having an iodine desorption rate of 70% or more according to the following formula 3 in the step of desorbing iodine by raising the temperature of the activated carbon from 90 ^° C to 450 ^° C:  &Quot; (3) &quot;  Iodine desorption (%) = desorbed iodine content (ppm) I total iodine adsorbed on activated carbon (ppm) X 100. [Claim 5]  The method according to claim 1, The activated carbon in the key step of the desorption of iodine was heated from 90 ^° C to 450 ^° C, to carbon oxides desorption rate by the equation (4) is 1 ¾> less, mono-production method for an iodine benzene:  &Quot; (4) &quot;  Carbon Oxide Desorption Rate (%) = Desorbed Carbon Oxide Content (ppm) I Total Carbon Oxide Content Absorbed in Activated Carbon (ppm) X 100. [Claim 6]  The method according to claim 1,  Wherein said gaseous impurities comprises mono-iodobenzene, which comprises from 0.1 vol% to 10 vol% iodine gas, from 15 vol% to 24 vol% of carbon oxide gas and from 70 vol% to 80 vol% &Lt; / RTI &gt; 7. In subsection 1 In the step of adsorbing gaseous impurities including iodine and carbon oxides generated in the firing step on activated carbon,  Iodine and carbon oxides are adsorbed in an amount of 80 to 90 parts by weight based on 100 parts by weight of the activated carbon. 8.  8. The method of claim 7,  Wherein the content of carbon oxide adsorbed on the activated carbon is 25 parts by weight or less based on 100 parts by weight of iodine adsorbed on the activated carbon. [Claim 9]  The method according to claim 1,  Wherein the carbon oxide comprises carbon monoxide or carbon dioxide. Claim 10  In Item 1, After the step of raising the activated carbon from 20 ^° C to 90 ^° C to desorb the carbon oxide,  Method for the preparation of mono-iodobenzene, further comprising neutralizing the desorbed carbon oxide Claim 11  The method according to claim 1,  After the step of recovering the desorbed iodine, And recovering the recovered iodine with benzene to produce multi-iodinated benzene. ^' [12] 12. The method of claim 11, And recovering the recovered iodine with benzene to produce multi-iodinated benzene. The process for producing mono-iodobenzene according to claim 1, wherein the multi-iodinated benzene is used as a repellent for the step of producing mono-iodobenzene. Way. Claim 13  In the above,  The zeolite catalyst may contain,  Exchanged zeolite catalyst in which the molar ratio of Si / AI is 5 to 100 and 2% to 50% of the ion exchange amount is ion-exchanged with an alkali metal or an alkaline earth metal. [14]  In addition,  Wherein the catalyst is selected from the group consisting of Y, BEA, and ZSM-5 zeolite. 15.  The method according to claim 1,  Wherein the multi-iodinated benzene comprises at least one member selected from the group consisting of m-di-iodobenzene, 0-di-iodobenzene, and tri-iodobenzene. Claim 16  A mono-iodobenzene obtained by the process for producing mono-iodobenzene according to claim 1.