JP2008142629A - Method for regenerating catalyst - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for regenerating a crystalline metallosilicate catalyst or a metal supported crystalline metallosilicate catalyst used for manufacturing hydroxy compounds by hydrolysis of chlorinated hydrocarbon compounds, in which the activity of the catalyst deteriorated according to use can be recovered to a sufficient high level. <P>SOLUTION: The catalyst for use in regeneration is treated at 400°C or higher under the atmosphere of inert gas. The hydrolysis reaction includes a reaction substituting chlorine of the chlorinated hydrocarbon compounds with a hydroxide group and further a reaction substantially converting chlorobenzene to phenol. Nitrogen is preferable for the inert gas from a cost point of view. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for regenerating a catalyst. More specifically, the present invention relates to a method for regenerating a crystalline metallosilicate catalyst or a metal-supported crystalline metallosilicate catalyst used when hydrolyzing a chlorinated hydrocarbon compound to produce a hydroxy compound, The present invention relates to a method for regenerating a catalyst having an excellent feature that the activity of a catalyst that has caused a decrease in activity can be restored to a sufficiently high level.

  A technique using a crystalline metallosilicate catalyst or a metal-supported crystalline metallosilicate catalyst when hydrolyzing a chlorinated hydrocarbon compound to produce a hydroxy compound is known. In this reaction, since coke is deposited on the catalyst and the activity is reduced, it is also known to restore the activity by air calcination. (For example, refer to Patent Documents 1 to 4.)

  However, the activity of the catalyst decreases with use, and an excellent method for recovering the activity to a sufficiently high level with good reproducibility has not been proposed.

JP-A-62-192330 JP-A-4-117338 Japanese Patent Laid-Open No. 4-117339 JP-A-4-334333

  In such a situation, the problem to be solved by the present invention is a method for regenerating a crystalline metallosilicate catalyst or a metal-supported crystalline metallosilicate catalyst used when hydrolyzing a chlorinated hydrocarbon compound to produce a hydroxy compound. Thus, the present invention is to provide a method for regenerating a catalyst having an excellent feature that the activity of a catalyst that has decreased in activity with use can be recovered to a sufficiently high level.

  That is, the present invention relates to a method for regenerating a crystalline metallosilicate catalyst or a metal-supported crystalline metallosilicate catalyst used when hydrolyzing a chlorinated hydrocarbon compound to produce a hydroxy compound, wherein the catalyst used for regeneration is used. The present invention relates to a method for regenerating a catalyst which is treated at a temperature of 400 ° C. or higher in an inert gas atmosphere.

  According to the present invention, there is provided a method for regenerating a crystalline metallosilicate catalyst or a metal-supported crystalline metallosilicate catalyst used for producing a hydroxy compound by hydrolyzing a chlorinated hydrocarbon compound, wherein the activity decreases with use. It is possible to provide a method for regenerating a catalyst having an excellent characteristic that the activity of the resulting catalyst can be recovered to a sufficiently high level.

  The catalyst targeted by the present invention is a crystalline metallosilicate catalyst or a metal-supported crystalline metallosilicate catalyst used when hydrolyzing a chlorinated hydrocarbon compound to produce a hydroxy compound.

  Examples of the hydrolysis reaction include a reaction of substituting chlorine in the chlorinated hydrocarbon compound with a hydroxyl group, and more specifically, a reaction of converting chlorobenzene into phenol.

  The metallosilicate of the crystalline metallosilicate catalyst contains Si as an essential component, and includes Al, Cu, Ga, Fe, B, Zn, Cr, Be, Co, La, Ge, Ti, Zr, Hf, V, Ni, Including one or more metal elements selected from Sb, Bi, Nb, etc., Si and other metal atomic ratio, Si / Me atomic ratio (where Me is Al, Cu, Ga, Fe, B, 1 or 2 or more metal elements selected from Zn, Cr, Be, Co, La, Ge, Ti, Zr, Hf, V, Ni, Sb, Bi, Nb, etc.) are 5 or more. Metallosilicates are more preferred, but crystalline silicates composed of silicon dioxide substantially free of Me component may also be used. The crystallinity of the crystalline metallosilicate means that a diffraction peak is observed in X-ray diffraction.

  The metal-supported crystalline metallosilicate catalyst is obtained by supporting the above-described crystalline metallosilicate on a metal as a carrier. As the metal, Al, Cu, La, Ce, Ni, Pd, Pt, Fe, Co, or the like can be used. The metal loading of the crystalline metallosilicate in the metal-supporting crystalline metallosilicate catalyst is usually 0.1 to 10 wt%.

  For the crystalline metallosilicate catalyst and the metal-supported crystalline metallosilicate catalyst, for example, “Science and Engineering of Zeolite” (by Yoshio Ono and Takeaki Yashima, Kodansha) can be referred to.

  Examples of a method for producing a hydroxy compound by hydrolyzing a chlorinated hydrocarbon compound using a crystalline metallosilicate catalyst or a metal-supported crystalline metallosilicate catalyst include the following methods.

  There is no restriction | limiting in particular in the method of manufacturing a hydroxy compound by hydrolyzing a chlorinated hydrocarbon compound, A well-known method can be used. An example of the reaction of converting chlorobenzene to phenol is as follows. The reaction is carried out in either a liquid phase or a gas phase, but usually a gas phase reaction is used. The reaction form may be a fixed bed, a fluidized bed, or a moving bed. The molar ratio of water to chlorinated hydrocarbon (water / chlorinated hydrocarbon) is usually 0.5 to 10, the reaction temperature is 160 to 600 ° C., and the reaction pressure may be any of reduced pressure, normal pressure, and pressurized pressure. However, it is usually atmospheric pressure.

  In the regeneration method of the present invention, a catalyst to be regenerated is treated at a temperature of 400 ° C. or higher in an inert gas atmosphere.

  As the inert gas, nitrogen is preferable from the viewpoint of cost.

  The regeneration temperature is 400 ° C. or higher, preferably 450 ° C. or higher. If the regeneration temperature is too low, the regeneration effect cannot be obtained sufficiently. The upper limit of the regeneration temperature is preferably 850 ° C. or less from the viewpoint of preventing sintering of the catalyst. If the regeneration temperature is too high, the catalyst and metal components may sinter and cause a decrease in activity.

  A preferred specific method of regeneration is as follows.

  When the reaction mode is fixed bed, water and chlorinated hydrocarbon compound are supplied to the fixed bed reactor packed with catalyst to conduct hydrolysis reaction, and then water and chlorinated hydrocarbon supply are stopped and water is added. It is preferable to terminate the decomposition reaction, and then replace the catalyst layer with the inert gas by supplying the inert gas to the fixed bed reactor, and then regenerate by holding the catalyst at a temperature of 400 ° C. or higher. .

  By replacing the catalyst layer with an inert gas, the concentration of gas components other than the inert gas in the catalyst layer, particularly the oxygen concentration, must be reduced. Due to the presence of oxygen, hydrocarbons, chlorinated hydrocarbons, and hydroxy compounds adsorbed on the catalyst during the treatment may burn, and the temperature of the catalyst will rise and the catalyst may deteriorate due to sintering. There is. The oxygen concentration in the catalyst layer is 2 vol% or less, preferably 1 vol% or less, more preferably 500 vol ppm or less.

  The treatment time at a temperature of 400 ° C. or higher is preferably 0.5 hours to 5 hours. When the treatment time is short, desorption of hydrocarbons, chlorinated hydrocarbons, hydroxy compounds and hydrogen chloride adsorbed on the catalyst becomes insufficient, and the activity is not sufficiently recovered. On the other hand, if the treatment time is long, it takes time to regenerate the catalyst, the reaction time is shortened, and productivity is lowered.

  When the reaction mode is a fluidized bed or moving bed, the catalyst is continuously or intermittently withdrawn from the reactor while water and chlorinated hydrocarbon compounds are supplied to the reactor to carry out the hydrolysis reaction. In addition, a prescription is preferably adopted in which the catalyst is regenerated at a temperature of 400 ° C. or higher after replacement with an inert gas in a catalyst regeneration treatment facility with an inert gas installed separately, and then this is returned to the reactor.

  In the present invention, the catalyst regenerated with an inert gas is preferably further calcined with air. This makes it possible to recover the activity of the catalyst after regeneration to a higher level. A preferred specific method for air baking is as follows.

  When the reaction form is a fixed bed, after the regeneration treatment with the inert gas is completed, the temperature of the catalyst layer is adjusted to 300 ° C to 600 ° C, more preferably 350 ° C to 500 ° C, and the supply of the inert gas is stopped. The catalyst layer is then air calcined by supplying air to the fixed bed reactor. If the temperature of the catalyst layer during air firing is too low, the effect of air firing is low. If the temperature of the catalyst layer is too high, the catalyst deteriorates due to sintering. In addition, you may change temperature within said temperature range during air baking.

  The air firing time is preferably 0.5 hours to 5 hours. If the treatment time is too short, the effect of air baking is insufficient and the activity does not recover to a higher level. On the other hand, if the treatment time is long, it takes time to regenerate the catalyst, the reaction time is shortened, and productivity is lowered.

  When the reaction mode is a fluidized bed or moving bed, the catalyst is continuously or intermittently withdrawn from the reactor while water and chlorinated hydrocarbon compounds are supplied to the reactor to carry out the hydrolysis reaction. A prescription is preferably adopted in which the catalyst is treated in a catalyst regeneration treatment facility and an air calcination facility with an inert gas separately installed, and then returned to the reactor.

  In this air firing, a mixed gas of an inert gas and air having a lower oxygen concentration may be used instead of air.

Next, the present invention will be described with reference to examples.
Example 1
In 150 ml of ion-exchanged water, 1.87 g (0.05 mol / L) of commercially available nickel acetate tetrahydrate (99.9%, manufactured by Wako Pure Chemical Industries, Ltd.) was stirred and dissolved at room temperature to prepare a nickel acetate aqueous solution. . 30.0 g of commercially available Na-ZSM-5 zeolite (Si / Al = 25 powder manufactured by N.E. Chemcat) was added to the nickel acetate aqueous solution, and the mixture was heated at 100 ° C. with stirring with a stirrer for 21 hours. Impregnation and ion exchange were performed. The solid content was filtered, washed with ion-exchanged water, dried at 120 ° C. for 4 hours, and further calcined at 400 ° C. for 5 hours under air flow to obtain a catalyst.
A fixed bed evaporator at 200 ° C. and a glass fixed bed reactor with an inner diameter of 17 mmφ were arranged directly. 16.7 g of the above catalyst was charged into a glass fixed bed reactor and maintained at 400 ° C. 1 g / h of water and 5 g / h of chlorobenzene (special grade manufactured by Wako Pure Chemical Industries, Ltd.) are supplied to a fixed bed evaporator at 200 ° C. in which nitrogen 18 ml / min is circulated, and (water / chlorobenzene = 1.3 mol). Ratio) The reaction was started.
0.7 hours after the start of the reaction, the product gas was absorbed in a toluene solvent, and the product was analyzed by gas chromatography. Monochlorobenzene conversion was 26.7%, phenol selectivity was 84.6%, and phenol yield was 22.6. %, And benzene selectivity was 13.5%. After 4 hours, the supply of water and chlorobenzene was stopped to stop the reaction. (Reaction 4 hours)
Nitrogen 50 ml / min was circulated, and the fixed bed reactor was held at 415 ° C. for 1 hour (nitrogen treatment).
Next, the fixed bed reactor was maintained at 350 ° C., the flow of nitrogen was stopped, air 145 ml / min was flowed, the fixed bed reactor was heated from 350 ° C. to 450 ° C., and held at 450 ° C. for 1 hour. (Air firing).
Next, the air flow was stopped, the fixed bed reactor was kept at 400 ° C. under nitrogen flow, 1 g / h of water was added to the fixed bed evaporator at 200 ° C., and 5 g / h of chlorobenzene (special grade manufactured by Wako Pure Chemical Industries) was used. h and the reaction was carried out again for 4 hours.
The reaction was repeated for 4 hours, nitrogen treatment and air calcination as described above, and then the reaction was resumed. After 3 hours (cumulative reaction time was 11.0 hours), the product gas was absorbed in the toluene solvent, and the product was When analyzed by gas chromatography, the monochlorobenzene conversion was 20.2%, the phenol selectivity was 87.7%, the phenol yield was 17.7%, and the benzene selectivity was 10.3.

Example 2
In the same catalyst, catalyst loading amount, and reaction equipment as in Example 1, 2 g / h of water was added to a fixed bed evaporator at 200 ° C. in which nitrogen 18 ml / min was circulated, and chlorobenzene (special grade manufactured by Wako Pure Chemical Industries). Was fed at 5 g / h (water / chlorobenzene = 2.5 molar ratio), and the reaction was started at the same reaction temperature as in Example 1. After 2 hours, the supply of water and chlorobenzene was stopped to stop the reaction (reaction 2 hours).
Nitrogen was allowed to flow at 50 ml / min, and the fixed bed reactor was maintained at 500 ° C. for 2 hours (nitrogen treatment).
Next, the fixed bed reactor was kept at 400 ° C., the flow of nitrogen was stopped, and air was circulated at 145 ml / min. The fixed bed reactor was heated from 400 ° C. to 450 ° C. and held at 450 ° C. for 1 hour (air calcination).
Next, the air flow was stopped, the fixed bed reactor was kept at 400 ° C. under a nitrogen flow, 2 g / h of water was added to the fixed bed evaporator at 200 ° C., and 5 g / h of chlorobenzene (special grade manufactured by Wako Pure Chemical Industries) was used. h and the reaction was carried out again for 2 hours.
The reaction was repeated for 2 hours, nitrogen treatment and air calcination 13 times as described above, and then the reaction was resumed. After 0.6 hours (cumulative reaction time was 26.6 hours), the product gas was absorbed in the toluene solvent, When the product was analyzed by gas chromatography, the conversion of monochlorobenzene, phenol selectivity, phenol yield, and benzene selectivity were measured, and the results as shown in No. 1 in Table 1 were obtained. After 2 hours, the supply of water and chlorobenzene was stopped to stop the reaction.
After flowing nitrogen at 50 ml / min, holding the fixed bed reactor at 500 ° C. for 2 hours, treating with nitrogen, holding the fixed bed reactor at 400 ° C. without air calcination, flowing nitrogen at 18 ml / min 2 g / h of water and 5 g / h of chlorobenzene (special grade manufactured by Wako Pure Chemical Industries) were supplied to the fixed bed evaporator at 200 ° C. (water / chlorobenzene = 2.5 molar ratio), and the reaction was resumed. .
After 0.6 hours (cumulative reaction time was 28.6 hours), the product gas was absorbed in a toluene solvent, and the product was analyzed by gas chromatography. Monochlorobenzene conversion, phenol selectivity, phenol yield, benzene selection When the rate was measured, the result shown in Table 1 No. 2 was obtained. After 2 hours, the supply of water and chlorobenzene was stopped to stop the reaction.
As described above, nitrogen treatment was repeated for 2 hours without air calcination, and the product gas 0.5 hours after the start of the reaction was absorbed in a toluene solvent, and the product was analyzed by gas chromatography. Results 3 and 4 were obtained.
Even when only the nitrogen treatment was performed, the conversion rate of monochlorobenzene and the yield of phenol were improved.

Comparative Example 1
The same reaction start operation as in Example 1 was carried out using the same catalyst, catalyst loading, and reaction equipment as in Example 1, 1.5 hours after the start of the reaction, the product gas was absorbed in a toluene solvent, and the product was gas chromatographed. As a result of analysis by a graph, it was found that the conversion of monochlorobenzene was 26.2%, the phenol selectivity was 84.0%, the phenol yield was 22.0%, and the benzene selectivity was 13.3%. After 4 hours, the supply of water and chlorobenzene was stopped. Furthermore, the nitrogen flow was stopped.
Unlike Example 1, air was circulated at 145 ml / min with no nitrogen treatment, the fixed bed reactor was heated from 400 ° C. to 450 ° C. and held at 450 ° C. for 1 hour. After that, the reaction was carried out again for 4 hours.
After repeating the air calcination as described above for 4 hours, the reaction was restarted, and after 3 hours (cumulative reaction time was 11.0 hours), the product gas was absorbed in a toluene solvent, and the product was analyzed by gas chromatography. As a result, the monochlorobenzene conversion rate was 17.9%, the phenol selectivity was 83.6%, the phenol yield was 15.0%, and the benzene selectivity was 13.2%.

Claims (5)

A method for regenerating a crystalline metallosilicate catalyst or a metal-supported crystalline metallosilicate catalyst used for producing a hydroxy compound by hydrolyzing a chlorinated hydrocarbon compound, wherein the catalyst used for regeneration is in an inert gas atmosphere. A method for regenerating a catalyst, wherein the catalyst is treated at a temperature of 400 ° C. or higher. The regeneration method according to claim 1, wherein treatment is performed with an inert gas, followed by air firing. The regeneration method according to claim 1, wherein the inert gas is nitrogen. The regeneration method according to claim 1, wherein the hydrolysis reaction is a reaction in which chlorine of the chlorinated hydrocarbon compound is substituted with a hydroxyl group. The regeneration method according to claim 1, wherein the hydrolysis reaction is a reaction for converting chlorobenzene into phenol.