JP3141944B2 - Pretreatment method for catalyst slurry - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for continuously producing and collecting corresponding cycloolefins, particularly cyclohexenes, by partially hydrogenating a monocyclic aromatic hydrocarbon. In particular, the present invention relates to a method for pretreating a catalyst slurry for easily and stably performing continuous production and collection of cycloolefins.

Cyclohexenes have high value as intermediate raw materials for organic chemical products, and are particularly important as polyamide raw materials and lysine raw materials.

(Prior Art) As a method for producing cyclohexenes, for example,
(1) A method using a catalyst composition containing water and an alkaline agent and a Group VIII element of the periodic table (Japanese Patent Publication No. 56-22850), (2) Ruthenium catalyst, Group IA metal and Group IIA metal of the periodic table A reaction in the presence of a neutral or acidic aqueous solution containing a salt of at least one cation selected from manganese and manganese (Japanese Patent Publication No. 57-7607);
(3) a method of performing a reaction in the presence of water with a ruthenium catalyst dispersed in silica gel derived from a hydrolysis product of silicon alkoxide (Japanese Patent Publication No. 60-59215);
(4) A method in which a reaction is carried out in the presence of a catalyst in which ruthenium is supported on barium sulfate, water and an additive (JP-A-61-4022)
No. 6), (5) A method of carrying out a reaction in the presence of a catalyst in which ruthenium is supported on a rare earth element-containing compound, water and an alkali agent (Japanese Patent Publication No. 1-29174), (6) Fine particles of metal ruthenium and zirconium oxide Alternatively, a method in which the reaction is carried out in the presence of hafnium oxide and water (Japanese Patent Laid-Open No. 62-8133)
No. 2), (7) a method in which a reaction is carried out in the presence of a ruthenium catalyst using a monocyclic aromatic hydrocarbon substantially containing no sulfur compound as a raw material (Japanese Patent Application Laid-Open No. 60-255738), (8)
A method in which a reaction is carried out in the presence of a ruthenium catalyst and water in an atmosphere in which iron does not accumulate on the catalyst (JP-A-62-67033)
All of these have been proposed, and all of these are mixed with a ruthenium catalyst or a catalyst slurry in which various additives are dispersed or dissolved in water and mixed with monocyclic aromatic hydrocarbons and hydrogen in a liquid phase to contact cycloolefins. How to get.

(Problems to be Solved by the Invention) When a realistic continuous production process of cycloolefins is to be constructed using these conventionally known methods, a catalyst slurry composed of a ruthenium catalyst and water (hereinafter, referred to as “ Aqueous phase) and the reaction product (hereinafter, referred to as
(Abbreviated as "oil phase"). If the components of the water phase, for example, catalysts and additives (solids, alkaline substances, acidic substances, etc.) are excessively mixed into the oil phase, clogging of the process pipes due to the mixed substances and the usual use Problems such as corrosion of materials are expected to occur. This problem can be solved to some extent, for example, by providing a filtration device for removing contaminants or a washing device, but the equipment and operation for that purpose are industrially easy. Is hard to say. Also, in the case of continuous partial hydrogenation, if catalysts and additives are mixed in and out of the oil phase, even if they are added little by little, some operation or equipment is required to keep the reaction system stable over the long term. It is clear that it will be.

Therefore, from an industrial point of view, there is a strong demand for some method that does not excessively mix the components of the slurry phase into the oil phase.

Here, “excessive” refers to an amount exceeding the saturation solubility of the aqueous phase component in the oil phase under partial hydrogenation reaction conditions or phase separation conditions (for example, temperature or composition of the oil phase composed of reaction products). In general, it is a problem from about several times the saturation solubility, so the amount is referred to. More specifically, for example, according to the study of the present inventors, the aqueous phase
18 using the weight% of ZnSO ₄ · 7H ₂ O solution and the catalyst, hydrogen pressure 50k
g / cm ² G, Partial hydrogenation of benzene at 150 ° C, 50% by mole of benzene, 50% by mole of cyclohexene and cyclohexane in total Is about 1% by weight and ZnSO
_Since the saturation solubility of ₄ is 1 ppm or less (100 ppm or less with respect to water dissolved in the oil phase), “excess” means an amount several times or more than these. In addition, in the case where the above components are excessively mixed, the mixing of the solid components in the aqueous phase occurs in most cases.

From this viewpoint, if we look at the conventionally known technologies, for example, in the above-mentioned conventional technologies (1) to (6), it is also described that the reaction is continuously performed by a liquid phase suspension method therein. Although all the examples are batch reactions, there is no description from the viewpoint of the present inventors.

The conventional techniques (5) to (8) are techniques invented by the present inventors themselves.
In (8), a continuous flow reaction was actually performed, and the partial hydrogenation reaction was successfully performed with a relatively stable reaction result for 100 to 500 hours. The amount is not described, and no studies have been made from the viewpoint of the present invention.

On the other hand, there are only examples (7) and (8) in which the partial hydrogenation reaction of a monocyclic aromatic hydrocarbon is continuously performed using a catalyst slurry composed of a ruthenium catalyst and water. They can only consider themselves.

In other words, it is obvious that the present invention has been clarified for the first time by the present inventors' continuous and careful observation and examination.

(Means for Solving the Problems) As described above, the present inventors have performed a partial hydrogenation reaction of a monocyclic aromatic hydrocarbon continuously using various catalyst slurries, and not only the reaction results, A detailed study was also made on the separation of the slurry phase and the oil phase. As a result, when such a flow reaction is easily started, the constituent materials of the catalyst slurry, which should be originally held in the aqueous phase, are partially mixed into the oil phase,
It has been found that it leaks out and has a negative effect on later process operations and materials. In addition, it has been concluded that this phenomenon occurs quite universally, although the degree varies depending on the difference in the components of the catalyst slurry. Furthermore, this phenomenon is not only apparent by observing the reaction mixture after performing a normal batch reaction, but also in the flow reaction even if the oil phase and the slurry phase after the batch reaction seem to be clearly separated. It is also known that observations may be made, and to prevent this phenomenon, it is not enough to provide a stationary separation tank having a size large enough to separate most of the catalyst slurry from the oil phase. Also got.

The present inventors have made intensive studies to avoid such a phenomenon, and as a result, have reached the present invention. That is, the present invention
A monocyclic aromatic hydrocarbon and hydrogen are continuously supplied to a catalyst slurry composed of a ruthenium catalyst and water to perform a partial hydrogenation reaction, and an aqueous phase as the catalyst slurry and an oil phase composed of a reaction product are separated. In a method of separating the phase and continuously collecting the oil phase, the catalyst slurry is mixed, and at a temperature of 60 to 180 ° C. in the absence of an oil phase component such as a raw material monocyclic aromatic hydrocarbon. A method for pretreating a catalyst slurry characterized by holding for a predetermined time, which provides a method for reliably separating a slurry phase and an oil phase and suppressing mixing of a component of the catalyst slurry into the oil phase. is there.

 Hereinafter, specific embodiments of the present invention will be described.

The catalyst slurry composed of the ruthenium catalyst and water in the present invention may contain various additives other than the ruthenium catalyst and water. As the ruthenium catalyst, metal ruthenium fine particles and ruthenium in various supports, for example, rare earth element compounds, Ti, Zr, Hf, Nb, Ta, Cr, Fe,
Co, Al, Ga, oxides and hydroxides such as Si or hydrates thereof, and those supported on water-insoluble salts such as barium sulfate can be mentioned, the catalyst is a component other than ruthenium, for example, , Cu, Fe, Zn, Ag, etc. may be included. There are many additives such as those that dissolve in water and those that do not, but salts of Group IA metals, Group IIA metals, salts such as Zn and Co, various alkali agents, Ti, Zr, Hf,
Examples include oxides and hydroxides of Nb, Ta, Cr, Fe, Co, Al, Ga, Si and the like, hydrates thereof, and activated carbon.

In particular, metal ruthenium fine particles and Ti, Zr, Hf, Nb, Ta,
A method of using an oxide or hydroxide of Cr, Fe, Co, Al, Ga, Si or the like or a hydrate thereof as a solid component, and using an aqueous solution of a salt of Zn (for example, the conventional technology (6)).
Can be preferably used because of high selectivity and yield of cycloolefin production by partial hydrogenation reaction. The slurry concentration, that is, the concentration of the solid component in the aqueous phase is 1 × 10 ^{−3 to} 0.3 times by weight, preferably 1 × 1 to ³ times the weight of coexisting water.
0 ^{-2 to} 0.1 times by weight.

The monocyclic aromatic hydrocarbon supplied to the partial hydrogenation reaction refers to benzene, toluene, xylenes, and lower alkylbenzenes having an alkyl group having 4 or less carbon atoms.

The partial hydrogenation reaction is usually performed at 100 to 200 ° C. under a hydrogen pressure of 10 to 100 kg / cm ² G. The reaction product to be taken out as an oil phase is a mixture of cyclohexenes, cyclohexanes and unreacted raw materials.

In the present invention, the partial hydrogenation reaction using the catalyst slurry is continuously performed, and the reaction product is continuously collected by oil-water separation.
This is a method for pretreating a catalyst slurry which is maintained at a temperature of 0 ° C. for a predetermined time.

The pretreatment of the catalyst slurry of the method of the present invention is performed in the absence of an oil phase component such as a raw material monocyclic aromatic hydrocarbon. However, the presence of a very small amount that can be dissolved in the slurry phase under the conditions during the treatment does not matter. Also,
The pretreatment of the catalyst slurry of the present invention is for the first time used in a partial hydrogenation reaction, and the catalyst slurry once subjected to the pretreatment of the present invention is used after the partial hydrogenation reaction,
When cooled and used again in the reaction, the pretreatment of the present invention is not particularly required.

The gas phase for carrying out the method of the present invention is not particularly limited as long as it does not adversely affect the catalyst, such as water vapor, hydrogen, air, or nitrogen, but is preferably carried out in a hydrogen or nitrogen atmosphere.
In addition, when the reaction is performed in the presence of hydrogen, the activity and selectivity to the reaction of the catalyst can be stably obtained immediately after the start of the flow reaction. It is carried out under a hydrogen pressure of 1 to 100 kg / cm ² G, preferably equivalent to the pressure in the partial hydrogenation reaction.

The present invention is performed at a temperature of 60-180 ° C. If the temperature is lower than 60 ° C., the pretreatment takes an extremely long time, or the desired effects of the present invention cannot be obtained, which is not preferable.If the temperature exceeds 180 ° C., the catalyst itself may be denatured. It is not preferable because there is also. It is more preferable to carry out at a temperature of 100 to 150 ° C.

In the present invention, the above-mentioned condition is maintained for a predetermined time. Here, the predetermined period of time is different from the constituent components of the catalyst slurry and the treatment temperature and cannot be unconditionally determined, but is usually several hours to several days.

By subjecting the catalyst slurry to the treatment of the present invention, an aqueous phase (catalyst slurry phase) is obtained in a continuous partial hydrogenation reaction.
The reason why the oil and the oil phase can be surely separated from each other and the mixing of the components of the catalyst slurry into the oil phase can be suppressed is not always clear, but probably, even in a compound generally referred to as hydrophilic, microscopically, Some have a lipophilic surface,
This is considered to be one of the causes of contamination of the oil phase, and the present inventors believe that the treatment of the present invention changes the lipophilic surface to hydrophilic.

(Effects of the Invention) According to the present invention, the product of the partial hydrogenation reaction can be continuously obtained without excessive mixing of the constituent components of the catalyst slurry into the oil phase. Required operations,
The value is very large, as the equipment can be reduced.

(Examples) Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Example 1 2.5 g of a metal ruthenium fine particle catalyst (average crystallite size: 55 °) containing 7.4% by weight of zinc obtained by reducing RU (OH) ₃ previously containing a zinc compound, ZrO ₂ powder (average particle size: 0.35
_{μ) 15g, ZnSO 4 · 3Zn} (OH) 2 250mg, ZnSO 4 · 7H 2 O 18%
A catalyst slurry consisting of 1,400 ml of an aqueous solution was prepared with an internal volume of 3
And a continuous flow reactor having a standing tank for oil / water separation of about 100 ml inside and a Teflon coating applied to the liquid contact part.

Next, after replacing the gas phase with hydrogen, the mixture was stirred for 150 minutes.
Temperature to 1 ° C over 1 hour, introduce hydrogen and bring the total pressure to 50kg
/ cm ² G and kept for 20 hours to pretreat the catalyst slurry. Thereafter, benzene was supplied at a rate of 2 / Hr, and a partial hydrogenation reaction of benzene was continuously performed while maintaining the pressure at 150 ° C. and the hydrogen pressure at 50 kg / cm ² G.

After cooling the oil phase coming out of the oil-water separation standing tank, it passes through a polypropylene microporous filter, and becomes supersaturated by cooling, and the water in the oil phase that precipitates,
Alternatively, the components of the catalyst slurry excessively mixed in the oil phase are separated by filtration and aggregated, and these are removed from the oil phase,
The oil phase as a reaction product was continuously taken out. On the other hand, the water collected by coagulation and the components soluble in water were appropriately circulated to the reactor. This operation was continuously performed for 500 hours to obtain benzene, cyclohexene, and cyclohexane as partial hydrogenation reaction products.

During this time, a part of the water collected by coagulation was taken out, and the amount of the constituents (ZnSO ₄ ) of the water-soluble catalyst slurry contained therein was analyzed.
As very small as 10 to 30 ppm by weight. Further, after the completion of the flow reaction, the microporous filter was taken out, and the presence or absence of solid matter was observed. As a result, traces of white ZrO ₂ were observed. From these facts, it was found that the constituent components of the catalyst slurry mixed into the oil phase during the flow reaction were extremely small, and there was substantially no component other than the amount of water saturated at 150 ° C. in the oil phase. Was.

Example 2 The same operation as in Example 1 was continuously performed for 200 hours except that the pretreatment operation of the catalyst slurry was heated to 80 ° C. over 30 minutes and performed at this temperature for 48 hours. During this time, the Zn content in the water collected by coagulation is 10 to 50 ppm by weight, and a trace amount of white ZrO ₂ is attached to the microporous filter. It was found that the amount of the catalyst component mixed was extremely small, and there was substantially no water other than the amount of water saturated at 150 ° C. in the oil phase.

Comparative Example 1 The catalyst slurry was not pre-treated,
The same operation as in Example 1 was continuously performed for 200 hours except that the supply of benzene was started at 00 ° C. During this time, the Zn content in the water collected by coagulation was 80 to 600 ppm by weight.
Further, about 1.0 g of a mixture of ZrO ₂ and ruthenium catalyst was attached to the microporous filter, and it was found that the components of the catalyst slurry were excessively mixed into the oil phase.

Example 3 A catalyst was prepared in the same manner as in Example 1 except that a catalyst slurry comprising 70 g of a hydrogenation catalyst having 1% ruthenium supported on lanthanum hydroxide, 700 mg of zinc oxide, 35 g of sodium hydroxide, and 1400 ml of water was used. Pretreatment of the slurry and partial hydrogenation of benzene were performed. On the way, a part of the coagulated and collected water was taken out, and the amount of the constituent components of the catalyst slurry contained therein was analyzed.
It is an extremely small amount of 30 to 70 wt ppm as Na, and Zn
Was less than 0.2 ppm by weight. After the completion of the flow reaction, the microporous filter was taken out, and the presence or absence of solid matter was observed. As a result, only a trace amount of the hydrogenation catalyst was observed.

Comparative Example 2 The same operation as in Comparative Example 1 was performed except that the catalyst slurry of Example 3 was used. During this time, the Na content in the water collected by coagulation is 150 to 500 ppm by weight, and the Zn content is 0.5 to 2 ppm by weight.
Met. Approximately 2.
5 g of hydrogenation catalyst had been deposited.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B01J 21/00-37/36 C07C 13/20

Claims (1)

(57) [Claims] 1. A partial hydrogenation reaction is carried out by continuously supplying a monocyclic aromatic hydrocarbon and hydrogen to a catalyst slurry composed of a ruthenium catalyst and water, and an aqueous phase as the catalyst slurry and a reaction product In the method of separating the oil phase consisting of and continuously collecting the oil phase, the catalyst slurry is mixed, and in the absence of an oil phase component such as a raw material monocyclic aromatic hydrocarbon, 60 to 180. A method for pretreating a catalyst slurry, wherein the catalyst slurry is maintained at a temperature of ° C for a predetermined time.