JPH03238047A - Pretreatment of catalyst slurry - Google Patents

Abstract

PURPOSE:To easily and stably perform the continuous manufacturing and collection of cycloolefins by holding a catalyst slurry consisting of a ruthenium catalyst and water to 60-180 deg.C for a predetermined time under mixing. CONSTITUTION:In pretreating a catalyst slurry constituted of a ruthenium catalyst and water, monocyclic aromatic hydrocarbon and hydrogen are continuously supplied to the catalyst slurry to perform partial hydrogenating reaction and the aqueous phase being the catalyst slurry and on oil phase composed of a reaction product are separated to continuously collect the oil phase. The catalyst slurry is held to 60-180 deg.C for a predetermined time under mixing. Herein, the predetermined time varies depending on the constituents of the catalyst slurry or treatment temp. but is usually several hr or several days.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method for partially hydrogenating monocyclic aromatic hydrocarbons to continuously produce and collect corresponding cycloolefins, particularly cyclohexene. More specifically, the present invention relates to a method for pretreating a catalyst slurry for easily and stably continuous production and collection of cycloolefins.

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

(Prior art) As a method for producing cyclohexene, for example, (1)
A method using a catalyst composition containing water, an alkaline agent, and an element of group Ⅰ of the periodic table (Japanese Patent Publication No. 56-22850)
, (2) ruthenium catalyst and group IA metals of the periodic table,
A method in which the reaction is carried out in the presence of a neutral or acidic aqueous solution containing a salt of at least one cation selected from Group IIA metals and manganese (Japanese Patent Publication No. 57-7607);
(3) A method of reacting a ruthenium catalyst dispersed in silica gel derived from a hydrolysis product of silicon alkoxide in the presence of water (Japanese Patent Publication No. 60-59215), (4) Adding ruthenium to barium sulfate. supported catalyst,
A method of carrying out a reaction in the presence of water and additives (JP-A-61
(Japanese Patent Publication No. 129174), (5) A method in which the reaction is carried out in the presence of a catalyst in which ruthenium is supported on a rare earth element-containing compound, water, and an alkaline agent (Japanese Patent Publication No. 129174)
, (6) A method of reacting metallic ruthenium fine particles with zirconium oxide or hafnium oxide and water in the presence of water (JP-A-6281332), (7) A method of reacting metal ruthenium fine particles with zirconium oxide or hafnium oxide in the presence of water (JP-A-6281332); A method of conducting a reaction using a ring aromatic hydrocarbon as a raw material (Japanese Unexamined Patent Application Publication No. 1983-1999)
(Japanese Patent Laid-Open No. 62-67033), and (8) a method in which the reaction is carried out in the presence of a ruthenium catalyst and water in an atmosphere that does not accumulate iron on the catalyst. This is a method for obtaining cycloolefins by mixing and contacting a catalyst slurry in which a ruthenium catalyst and various additives are dispersed or dissolved in water with a monocyclic aromatic hydrocarbon and hydrogen in a liquid phase.

(Problems to be Solved by the Invention) When trying to construct a practical continuous production process for cycloolefins using these conventionally known methods, it is necessary to use a catalyst slurry (hereinafter referred to as " (abbreviated as “aqueous phase”) and the reaction product (hereinafter referred to as “
It is necessary to reliably separate the oil phase (abbreviated as "oil phase").

If the oil phase contains components of the aqueous phase, such as catalysts and additives (
If excessive amounts of solids, alkaline substances, acidic substances, etc.) are mixed in, it is expected that problems such as corrosion of normally used materials will occur if the process piping is clogged by the mixed substances. This problem can be solved to some extent by, for example, installing a filtration device or a water washing device to remove contaminants, but the equipment and operations for this are simple from an industrial perspective. It's hard to say. In addition, even in continuous partial hydrogenation reactions, if catalysts or additives are excessively mixed into the oil phase or leaked out, even in small amounts, some kind of operation or equipment is required to keep the reaction system stable in the long term. It is clear that this will happen.

Therefore, from an industrial standpoint, there is a strong desire for a method that prevents the components of the slurry phase from being excessively mixed into the oil phase.

Here, ``excessive j'' refers to the amount that exceeds the saturated solubility of the water phase components in the oil phase under the partial hydrogenation reaction conditions or phase separation conditions (e.g., temperature and composition of the oil phase consisting of reaction products), and In other words, it refers to the amount of saturated solubility, as it becomes a problem at several times the saturation solubility.More specifically, for example, according to the studies of the present inventors, 1 as the aqueous phase.
Using 8% by weight ZnSO4.7H20 aqueous solution and catalyst,
When performing a partial hydrogenation reaction of benzene at a hydrogen pressure of 50 kg/cnlG and 150°C to collect a reaction product containing 50 mol% of benzene and 50 mol% of cyclohexene and cyclohexane, water saturation of the oil phase The solubility is about 1% by weight, and the saturated solubility of ZnSO4 is 1
ppm or less (1100p for water dissolved in the oil phase)
p or less), so "excessive" refers to an amount that is several times or more. In addition, when there is excessive contamination of the above components, it is almost always the case that solid components of the aqueous phase are also contaminated.

From this point of view, if we look at conventionally known techniques, for example, in the conventional techniques (1) to (6) above, there is also a description that the reaction is carried out continuously by a liquid phase suspension method. However, all of the Examples are batch reactions, and there is no description from the viewpoint of the present inventors.

Furthermore, the above-mentioned conventional techniques (5) to (8) are techniques invented by the present inventors themselves, especially (7) and (8).
) actually performs a continuous flow reaction, with 100 to 500
Although they succeeded in performing a partial hydrogenation reaction with relatively stable reaction results over a period of time, there is no description of the contaminants in the collected oil phase or their amounts, and this study was conducted from the perspective of the present invention. Not talked about.

On the other hand, examples in which the partial hydrogenation reaction of monocyclic aromatic hydrocarbons was continuously carried out using a catalyst slurry composed of a ruthenium catalyst and water are (7) and (8) L is not used. There is no choice but to consider it by themselves.

In other words, it is obvious that the present invention was first discovered through continuous and careful observation and study by the inventors themselves.

(Means for Solving the Problems) As mentioned above, the present inventors conducted partial hydrogenation reactions of monocyclic aromatic hydrocarbons continuously using various catalyst slurries, and obtained not only reaction results but also A detailed study was also conducted on the separation of the slurry phase and oil phase.

As a result, if such distribution reactions are initiated too easily,
It has been discovered that a portion of the constituent substances of the catalyst slurry that should be retained in the aqueous phase mix into and flow out into the oil phase, causing adverse effects on subsequent process operations and material quality. Moreover,
Although the degree of this phenomenon varies depending on the constituent components of the catalyst slurry, we have come to the conclusion that it occurs fairly universally. Furthermore, this phenomenon cannot be understood just by observing the reaction mixture after a normal batch reaction; even if the oil phase and slurry phase appear to be separated neatly after a batch reaction, in a flow reaction It has also been found that this phenomenon may be observed, and in order to prevent this phenomenon,
It has also been found that it is insufficient to simply provide a stationary separation tank that is large enough to separate most of the catalyst slurry from the oil phase.

The present inventors have made extensive studies to avoid such a phenomenon, and as a result, have arrived at the present invention. That is, the present invention performs a partial hydrogenation reaction by continuously supplying a monocyclic aromatic hydrocarbon and hydrogen to a catalyst slurry composed of a ruthenium catalyst and water, and combines the aqueous phase, which is the catalyst slurry, with the reaction product. In this method, the catalyst slurry is mixed with 60 to 1
A pretreatment method for a catalyst slurry characterized by holding it at a temperature of 80°C for a predetermined period of time, which reliably separates a slurry phase and an oil phase and suppresses mixing of the constituent components of the catalyst slurry into the oil phase. It provides:

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 mercury. As a ruthenium catalyst, metal ruthenium fine particles or ruthenium can be used in various carriers, such as
Rare earth element compounds, Ti, Zr, IfXNb, Ta
, Cr, Fe, CoX112. Examples include those supported on oxides and hydroxides such as Ga and Si, or their hydrates, and water-insoluble salts such as barium sulfate, and catalysts supported on components other than ruthenium, such as C
There is no problem even if it contains u, Fes Zn, Ag, etc. There are many additives, including those that dissolve in water and those that do not, but salts of group IA metals, group mA metals,
Salts such as Zn and Go, various alkali agents, Ti, Z
r, Hf, Nb, Ta, Cr,, Fe, Co
, Al1°Ga, Si, oxides and hydroxides or hydrates thereof, and activated carbon.

In particular, metal ruthenium fine particles and Ti, Zr, llf
,,Nb.

A method using an aqueous solution of Zn salts using oxides, hydroxides, or hydrates thereof such as Ga, Si, etc. as a solid component (e.g., the method of using an aqueous solution of Zn salts) Technique (6)) has high selectivity and yield for cycloolefin production by partial hydrogenation reaction, and can be preferably used. The slurry concentration, that is, the concentration of solid components in the aqueous phase, is IXl, O-
The amount is 3 to 0.3 times by weight, preferably 1xio-2 to 0.1 times by weight.

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

Partial hydrogenation reaction is usually carried out at 100-200℃110-100℃
It is carried out under a hydrogen pressure of kg/cJG. The reaction product to be removed as an oil phase is a mixture of cyclohexanes, cyclohexanes and unreacted raw materials.

In the present invention, when a partial hydrogenation reaction using such a catalyst slurry is continuously performed and the reaction product is continuously collected by oil/water separation, the catalyst slurry is mixed with 60-100%
This is a catalyst slurry pretreatment method in which the catalyst slurry is maintained at a temperature of 80°C for a predetermined period of time.

The pretreatment of the catalyst slurry in the method of the present invention is carried out in the absence of oil phase components such as raw material monocyclic aromatic hydrocarbons. However, it may be present in a very small amount that can be dissolved in the slurry phase under the conditions during processing. Further, the pretreatment of the catalyst slurry of the present invention is for use in a partial hydrogenation reaction for the first time, and the catalyst slurry subjected to the pretreatment of the present invention is cooled after being used in the partial hydrogenation reaction. When the sample is used again in the reaction, there is no particular need to perform the pretreatment of the present invention.

The gas phase in carrying out the method of the present invention is not particularly limited, such as water vapor, hydrogen, air, or nitrogen, as long as it does not adversely affect the catalyst, but it is preferable to carry out the process in a hydrogen or nitrogen atmosphere. In addition, if it is carried out in the presence of hydrogen, it may be possible to stably obtain the activity and selectivity for the reaction of the catalyst immediately after the start of the flow reaction, so it can be said to be a more preferable method. In this case, the hydrogen pressure is 1 to 100 kg/cIil
G, preferably carried out under hydrogen pressure equivalent to the pressure in the partial hydrogenation reaction.

The invention is carried out at temperatures of 60-180°C. Temperatures lower than 60°C are undesirable because the pretreatment takes a significant amount of time and the desired effects of the present invention cannot be obtained, while temperatures higher than 180°C are accompanied by denaturation of the catalyst itself. This is not preferable as there may be cases where the value is 100 to 1.
It is even more preferable to carry out the reaction at a temperature of 50°C.

In the present invention, the temperature is maintained under the above conditions for a predetermined period of time.

Here, the predetermined time may vary depending on the components of the catalyst slurry and the processing temperature, but it is usually several hours to several days.

By subjecting the catalyst slurry to the treatment of the present invention, the aqueous phase (catalyst slurry phase) and oil phase can be reliably separated in continuous partial hydrogenation reactions, and the contamination of the constituent components of the catalyst slurry into the oil phase can be prevented. Although it is not necessarily clear why it can be suppressed,
Perhaps even in compounds that are generally said to be hydrophilic, some microscopically lipophilic surfaces exist, and this is thought to be a contributing factor to their incorporation into the oil phase. The present inventors believe that this is because this lipophilic surface changes to hydrophilicity.

11 2 (Effects of the Invention) According to the present invention, the product of the partial hydrogenation reaction can be obtained continuously without excessive mixing of the constituent components of the catalyst slurry into the oil phase, which is advantageous from an industrial point of view. Its value is extremely great, as it can reduce the amount of operations, equipment, etc. required for separation.

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

Example 1 Ru (01()) containing a zinc compound in advance
2.5 g of metal ruthenium fine particle catalyst (average crystallite size 55 particles) containing 7.4% by weight of zinc obtained by reducing ZrO
2 powder (average particle size 0.35 μ) 15 g, Zn
SO4・3Zn(OH)z 250mg, Zn5Oa
・7 A catalyst slurry consisting of 1,400 mff1 of an 18% aqueous solution of H2O was prepared with an internal volume of 31 and approximately 100 m1! The reactor was placed in a continuous flow reactor, which had a static tank for oil/water separation inside and had Teflon coating on the parts that came into contact with the liquid.

Next, after replacing the gas phase with hydrogen, 150
The temperature was raised to ℃ over 1 hour, and hydrogen was introduced to bring the total pressure to 50℃.
kg/c+flG for 20 hours, and the catalyst slurry was pretreated. After this, add benzene to 2ffi/Hr.
50kg/c+ff at 150℃ and 1 hydrogen pressure
The partial hydrogenation reaction of benzene was carried out continuously while maintaining G.

The oil phase that comes out of the oil-water separation stationary tank is cooled and then passed through a polypropylene microporous filter to remove water in the oil phase that becomes supersaturated and precipitates as it cools, or to remove excess water from the oil phase. The constituent components of the catalyst slurry mixed in were filtered out and coagulated, removed from the oil phase, and the oil phase, which was a reaction product, was continuously taken out. On the other hand, the coagulated and collected water and components soluble in water were appropriately circulated to the reaction apparatus. This operation was carried out continuously for 500 hours to obtain partial hydrogenation reaction products such as benzene, cyclohexene, and cyclohexane. .

During this time, a part of the coagulated water was taken out, and the constituent components of the water-soluble catalyst slurry (ZnSO4) contained therein were extracted.
When analyzing the amount of
The amount of Zn was extremely small, ranging from 10 to 30 ppm by weight. Further, after the completion of the flow reaction, the microporous filter was taken out and observed for the presence or absence of solid matter adhering to it, and it was found that only a trace amount of white ZrO□ was observed. From these facts, it can be seen that the constituent components of the catalyst slurry mixed into the oil phase during the flow reaction are extremely small, and there is virtually no water other than the saturated amount of water dissolved in the oil phase at 150"C. understood.

Example 2 The same operation as in Example 1 was carried out continuously for 200 hours, except that the pretreatment operation of the catalyst slurry was carried out by raising the temperature to 80° C. over 30 minutes and continuing at this temperature for 48 hours.

During this period, the Zn content in the coagulated water was 10 to 50 ppm by weight, and only a trace amount of white ZrO□ was attached to the microporous filter, and during the flow reaction, the Zn content was 10 to 50 ppm by weight. It was found that the amount of the catalyst constituents mixed in was extremely small, and that there was substantially no water other than the amount of water dissolved in the oil phase at 150°C.

Comparative Example 1 The same operation as in Example 1 was carried out continuously for 200 hours, except that the catalyst slurry was not pretreated and the supply of Hensen was started at 100°C during the temperature raising process to 150°C. During this period, the Zn content in the coagulated water was 80 to 600 ppm by weight. Also, about 1.0g for microporous filters.
A mixture of ZrO□ and ruthenium catalyst is attached,
It was found that the constituent components of the catalyst slurry were excessively mixed into the oil phase.

Example 3 70g of hydrogenation catalyst with 1% ruthenium supported on lanthanum hydroxide, 700g of zinc oxide, 35g of sodium hydroxide
The pretreatment of the catalyst slurry and the Hensen's partial hydrogenation reaction were carried out in the same manner as in Example 1, except that a catalyst slurry consisting of , and 1400 d of water was used. During the course of the coagulation collection, a portion of the water was taken out and the amount of the 5 6 component of the catalyst slurry contained therein was analyzed, and it was found that the amount of Na was extremely small at 30 to 70 ppm by weight based on the coagulated water. In addition, the Zn content was 0.2 ppm by weight or less. After the flow reaction was completed, the microporous filter was taken out and observed for the presence or absence of solid matter adhering to it, and it was found that only a trace amount of the hydrogenation catalyst was observed.

Comparative Example 2 The same operation as Comparative Example 2 was performed except that the catalyst slurry of Example 3 was used. During this period, the Na content in the coagulated water was 150 to 500 N ppm, and the Zn content was 0.5 to 2 it ppm. Approximately 2.5 g of hydrogenation catalyst was attached to the microporous filter after the completion of the flow reaction.

(1 other person)

Claims (1)

[Claims] 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 a water phase, which is the catalyst slurry, and an oil phase, which is a reaction product, are separated. In a method in which the oil phase is continuously collected by phase separation, the catalyst slurry is mixed with
A method for pre-treating a catalyst slurry, the method comprising maintaining the temperature at a temperature of ~180°C for a predetermined period of time.