JPS5810136B2 - Method for manufacturing dehydrogenation catalyst - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention involves contacting a carrier made of at least one porous material selected from α-alumina and silica aluminum with an aqueous solution of chloroplatinic acid or an aqueous solution containing chloroplatinic acid and iridium chloride. , a Pt-alkali carrier produced by adsorbing chloroplatinic acid or chloroplatinic acid and iridium chloride onto a carrier, drying it, reducing it with hydrogen, and then contacting it with an aqueous alkali solution to support an alkali. catalyst or Pt-Ir-alkali-supported catalyst between 420 and 65
The present invention relates to a method for producing a catalyst for producing phenylphenol by gas-phase catalytic dehydrogenation of a C1□ oxygen-containing compound represented by the following general formula (I) or (II), which is characterized by firing at 0°C.

Demand for phenylphenols has been rapidly increasing recently as raw materials for organic fine chemicals, but there are many problems with their production methods, and as demand increases, various new production methods centered on dehydrogenation methods have been proposed. However, a dehydrogenation catalyst that is industrially fully satisfactory has not been found.

One of the inventors also searched for a method for producing phenylphenol by dehydrogenation and found that a Pt-alkali-r-alumina (or synthetic silica-alumina with a high alumina content) catalyst had an excellent ability to selectively produce phenylphenol. Headline, patented (Japanese Patent No. 804485, 81
No. 5609, No. 857162.

) This method has many advantages over conventional methods, so it has been used for the industrial production of heavy O-phenylphenol, and is still in operation, but as a result of a more detailed study, it was found that this method is unique. The disadvantage is that even if the carrier has almost the same physical properties,
It has become clear that catalyst life varies widely due to factors that cannot be analyzed at this time.

As a result of various studies aimed at obtaining a catalyst with good activity and long life with good reproducibility, one of the non-inventors found out that adding a small amount of Ir was effective and applied for a patent (Japanese Patent Laid-Open No. 51-14
9248).

As a result, it seemed that the production of phenylphenol by the dehydrogenation method was almost completed, but when we conducted an even longer life test, we found that when r-alumina, etc. that had been left in the air for a long time was used as a carrier, r-alumina Physical property values and ESC
Although there was no change in the surface condition examined by A and IMA, we found that the catalyst life was significantly reduced, so we prepared an excellent dehydrogenation catalyst using a carrier in such a condition. As a result of various studies on how to do this, we arrived at the non-invention method.

r-Alumina or synthetic silica with alumina content of 90% or more
It is said that the catalytic performance of alumina fluctuates due to slight temperature changes, pH changes, etc. during production, and it is considered extremely difficult to maintain perfect reproducibility.

However, even when measured using the current state-of-the-art surface measurement method, it is generally difficult to predict changes in the catalytic ability of the support, and it is impossible to predict the catalyst life from physical property values or data from instrumental measurements. .

Therefore, the only way to develop long-life catalysts is through trial and error, and the results of the uninvented method are no different from that. However, the firing effect during phenylphenol synthesis is amazing, and without firing it can last up to 100 hours. There have been many examples of catalysts with a lifespan of only a few thousand hours after being fired (see examples).

However, no calcination effect is observed in the dehydrogenation reaction of cyclohexanol (phenol synthesis) or the dehydrogenation reaction of α-tetralone (α-naphthol synthesis), and when dehydrogenating cyclohexanol, the catalyst life is reduced by calcination. There are many cases.

These experimental results show that the uninvented method is a method that even experts in this field could not predict, and there have been no reports in the literature on increasing catalyst life through calcination. .

According to a detailed study by the inventors, the dehydrogenation catalyst that is effective in the selective production of phenylphenols has a BET surface area of 150 to 35 um7g and a low iron content (0
, 5% by weight or less) r-alumina is preferably used as a carrier,
Incorporation of silica up to 10% by weight often improves carrier performance.

That is, the carrier may be r-alumina for carriers having a relatively large pore volume or synthetic silica-alumina having an alumina content of 90% by weight or more.

In the case of synthetic silica-alumina, its BET surface area is 2
00-400 m'/g, and pore volume 0.5-0.9
5ml/g.

A representative example of r-alumina suitable for non-reaction is r-alumina for use as a support for indirect desulfurization catalysts.

As described in the above-mentioned patent obtained by one of the inventors, the catalyst composition has a pi loading of 0.3 to 3.0% by weight, ■ r
The supported amount is preferably 0 to 0.5 times the supported amount of PT, and the alkali is preferably Na and K oxides, and the supported amount of these oxides is preferably about 1 to 10% by weight of the catalyst weight.

If the amount of Pt supported is too small, both activity and lifespan will decrease, and Pt
If the supported amount is less than 0.1% by weight, it becomes unsuitable as a practical catalyst.

Even if the amount of Pt supported is too large, there is almost no problem in terms of reaction, but as the amount of Pt supported increases, it becomes difficult to support it uniformly, and there are also economic problems, so supporting more than necessary is not preferable.

In the end, it can be said that the practical range is 0.1 to 5.0% by weight, but more realistically 0.3 to 3.0% by weight is better, and the optimal range is 1.0 to 2.0%. It can be said that it is about % by weight.

The alkalis used in the non-inventive method include Na and K.
The oxide of Na or K is preferable, so Na or K is used in the catalyst production process.
It is preferable to use a water-soluble compound as a starting material that can be converted into an oxide of.

That is, P
r-alumina or 1 carrying t or pt and Ir
Silica containing 0% by weight or less of silica.

A catalyst supporting the necessary amount of alkali can be prepared by bringing it into contact with Lumina, and a suitable compound for this purpose is N
a or K hydroxide, carbonate, bicarbonate, formate,
There are acetates, nitrates, etc., and hydroxides and carbonates are particularly suitable from the viewpoint of cost and ease of handling.

It goes without saying that there is no problem in using both the Na oxide and the K oxide.

The amount of alkali added varies depending on the type of carrier used and the compound to be dehydrogenated. If the solid acidity of the carrier is strong or if the compound to be dehydrogenated is susceptible to carbonium ion reactions, the amount of alkali added may be reduced. Good results are often shown when the size is increased somewhat.

Although there are some variations as described above, in general, it is sufficient to add about 1 to 10% by weight of the catalyst weight as an alkali metal oxide (Na20 or Na20), especially 3 to 7% by weight.
It is desirable to have a certain amount of additive power.

If the amount added is too small, the acidity of the catalyst will not be neutralized, and side reactions such as decomposition and dehydration will actively occur, resulting in a decrease in target product selectivity.

If the amount added is too large, the catalyst activity will decrease, resulting in decreased productivity and shortened catalyst life.

Particular attention should be paid to the following points when preparing a catalyst using the non-inventive method:
The method is to support platinum or platinum and iridium in the form of a salt on a carrier, then reduce it with hydrogen to make most of the salt in a metallic state, and then support an alkali. It is highly desirable to carry out the hydrogen reduction at °C.

In many cases, there is no major problem even if the hydrogen reduction temperature is set to 300°C or lower or 400°C or higher, but if the hydrogen reduction temperature is set to 300°C or lower, the reduction time becomes long, and if it is set to 200°C or lower, sufficient reduction becomes difficult in practice.

When the temperature is 400℃ or higher, there are fewer problems than when the temperature is low.
As long as platinum sintering and support surface area reduction do not occur, there is little problem in reducing at higher temperatures.

However, since there is no advantage of high temperature reduction, it is safe to reduce at 400°C or lower.

The calcination after supporting the alkali is the core of the uninvented method, and although the reason for this is not clear as described above, the calcination effect is surprisingly large.

If the firing temperature is too low, the effect will not be achieved, and if the firing temperature is too high, the activity will be greatly reduced due to sintering of platinum and a decrease in the surface area of the carrier.

The optimum firing temperature varies depending on the firing time and firing atmosphere, but is generally 420 to 650°C, and better results are obtained when the firing time is longer at lower temperatures.

Further, it is preferable to perform the firing under gas flow, and gases used for this purpose include hydrogen, nitrogen, air, helium, and the like.

The maximum values of the type of circulating gas, firing temperature, and firing time vary depending on the type of carrier, catalyst composition, etc., and as mentioned above, there is a relationship between these variable factors, so it is not clear. 3 at 520-620℃ under air circulation
~1100 hours, preferably at 550~600°C for ~15~
420-500 by baking for 30 hours or under hydrogen flow
Good results have been obtained using a method of firing at a temperature of 20 to 80 hours.

Note that there is no need to limit the amount of gas flowing; there is no significant difference between a large amount of gas flowing and a small amount of flowing, and even if there is no gas flowing at all, there is no big difference from when gas is flowing.

It has also been observed that catalytic performance can be greatly improved in many cases by calcining the carrier before adding platinum or alkali at 500 to 650°C for 10 to 20 hours under air circulation. This is completely different from the firing effect shown here.
This effect is thought to be due to the combustion and removal of organic substances added when producing alumina.

As an experimental result that clearly shows this, the above-mentioned case of a degraded phase that has been left in the air for a long time to adsorb moisture is shown. However, when the catalyst is calcined under the same conditions after preparation, a surprisingly large effect is observed.

The dehydrogenation catalyst prepared by the uninvented method dehydrates a molecule in which oxygen is bonded to one of the carbon atoms in the form of a ketone or alcohol, which has a partially or fully hydrogenated biphenyl skeleton. It is effective when producing the corresponding phenylphenol from a base, and specifically, O-phenylphenol is produced from O-cyclohexylphenol or a dimer obtained by aldol condensation of cyclohexanone, and P- P- from cyclohexylphenol
It is effective when producing phenylphenol, but it is in the production of O-phenylphenol that the dehydrogenation catalyst produced by the uninvented method is especially effective, and in particular, when dehydrogenating O-cyclohexylphenol. The effect is significant.

Next, the non-invention method will be explained in more detail with reference to examples.

Example 1 Catalysts & Chemicals Co., Ltd. r-alumina pellet (φ1.5mm.

Molded product with a length of 3 to 5 mm, BET surface area of 226 m”/
g, thinning volume 0.85 ml/g) was used as a carrier, and after thoroughly deaerating the carrier and adding water to prevent destruction during alumina hydration, 20.6 g of the carrier was mixed with H2PtCl4.6.
H200,547g and IrCl4”H2O0,07
50 ml of distilled water in which 4 g of the noble metal salt had been dissolved was added, and the mixture was allowed to stand for 15 hours with occasional stirring, so that the noble metal salt was sufficiently adsorbed onto the carrier.

After drying this catalyst in an electric dryer at 110°C for 3 hours, it was filled into a Pyrex glass catalyst firing tube and hydrogen-reduced at 350-360°C for 8 hours while passing hydrogen at a rate of about 31/hr.

40 ml of distilled water containing 1.2 g of commercially available special grade caustic potash was added to this catalyst (21.0 g), and the caustic potash was adsorbed by the immersion method.

This catalyst was dried in an electric dryer to prepare a dehydrogenation catalyst.

This catalyst (1,0wt%Pt-0,2wt%Ir-5w
t%KOH-r-alumina) 30mA (17.5g)
was filled into the catalyst filling part of a molybdenum glass reaction tube with an inner diameter of 22 m and a length of 800 mm, and the mixture was placed in a tubular electric furnace.
Dehydrogenation reaction of O-cyclohexylphenol was carried out by a conventional flow method.

That is, using a metering pump installed in a constant temperature bath at 60°C, 0-cyclohexylphenol kept at 60°C was supplied at a rate of 9 ml/hour, and at the same time, hydrogen was supplied onto the catalyst at a rate of 31/hr to carry out the reaction. The furnace temperature was maintained at 350°C (
The minimum temperature of the catalyst layer during the reaction was 325-327℃)
.

The product was collected in a product collection trap heated with a ribbon heater, and the collected material was appropriately taken out of the system using a sampling cock, and was heated with 3% silicon XE-60-Chromosolve WAW (
The analysis was carried out by temperature-rising gas chromatography (column length: 5 m) using a silanized product as a packing material.

When the change in the product over time was determined, it was found that 150% immediately after the reaction.
The reaction rate was maintained at 93% or more and the 0-phenylphenol selectivity was 95mol1% or more until the time elapsed, but the reaction rate gradually decreased after that, so the reaction temperature was increased appropriately to maintain the reaction rate at 90% or more. did.

As a result, at 2000 hours after the start of the reaction, the reaction temperature was 40
At 2℃, reaction rate 95%〇-Phenylphenol selectivity 9
It showed 4mo1%.

However, after leaving this carrier unsealed in the air for about two years, a catalyst was prepared in exactly the same manner as above, and a dehydrogenation reaction of O-cyclohexylphenol was carried out in exactly the same manner as above. is O at a reaction rate of 99%.
- It showed a phenylphenol selectivity of 78 mo1%,
At 30 hours, the reaction rate decreased to 75% and the O-phenylphenol selectivity decreased to 79 mo1%, and increasing the reaction temperature and decreasing the feed rate of raw materials did not have much effect on improving the selectivity.

Therefore, 1 wt prepared in exactly the same manner as above
%Pt-0,2wt%Ir-5wt%KOH-degraded γ-
The alumina catalyst was heated at 560 to 5
When attempting to dehydrogenate O-cyclohexylphenol using the above method using a catalyst calcined at 90°C for 15 hours,
Even after 3000 hours, the reaction rate was 98% and the O-cyclohexylphenol selectivity was 93 mo1%.

Note that the reaction temperature at this time was 382°C.

In this experiment, when ■r was not added, the reaction rate was only 53% and the O-phenylphenol selectivity was only 72 mo1% even immediately after the reaction started when the catalyst was used before calcination, and it could not be used as an industrial dehydrogenation catalyst. However, when calcined in exactly the same manner as above, immediately after the start of the reaction, the reaction rate was 97%, the 0-phenylphenol selectivity was 74mo7%, and 30 hours after the start of the reaction, the reaction temperature was 415°C, the reaction rate was 97%, and the 0-phenylphenol selectivity was 97%, 0- The phenylphenol selectivity was 93 mo1%, and the firing effect was clear in this case as well.

Example 2 Sumitomo activated alumina KHA-24 (spherical shape with a diameter of 2 to 4 mm,
BET surface area 150~180g/g, pore volume 0.5~
0.6 ml/g) as a carrier, 2.5 wt% P t -7, 0 wt% Na2CO3 in exactly the same manner as in Example 1.
- Prepare an activated alumina catalyst and dehydrate a mixture of P-cyclohexylphenol and O-cyclohexylphenol (synthesized by reaction of phenol and cyclohexene, content of 0-cyclohexylphenol 57%) under exactly the same conditions as in Example 1. (Due to the melting point, the raw material feed pump was placed in a constant temperature bath at 100°C.

In addition, the product trapping trap can also be used with a ribbon heater.
).

In this experiment, the reaction rate was 100 at 100 hours after the start of the reaction.
%, phenylphenol selectivity was 93 mo 1%, but at 250 hours it was 96% and 93 mo 1, respectively.
%, so the temperature was gradually raised, and at the 1000th hour, the reaction temperature (furnace temperature) was 395°C, the reaction rate was 97%, and the selectivity was 93m.
o1%.

On the other hand, when the alkali-supported catalyst was calcined at 590 to 620°C for 10 hours in a nitrogen flow of 112/hr, the reaction results were not much different from those without calcining until about 500 hours after the start of the reaction. The reaction results at the 1000th hour were reaction temperature (furnace temperature) 380°C, reaction rate 98%, and selectivity 95m.
Even after 2000 hours at o7%, a good product was exhibited at a reaction temperature of 395° C., a reaction rate of 97%, and a selectivity of 93 mo1%, and the firing effect was clear.

Example 3 γ-Alumina pellets manufactured by Catalysts and Chemicals (φ1.5 mm)
.

Molded product with a length of 3 to 5 mm, BET surface area of 320 m”
/ g, pore volume 0.68 ml/g, SiO2 content 1.
A carrier containing 91 wt% Fe and 0.03 wt% Fe as Fe2O3 was fired for 20 hours while passing air at a flow rate of 3 to 51/hr, and 1.0 wt% Pt was prepared in exactly the same manner as in Example 1. -2CO3- to 3.5wt%
A γ-alumina catalyst was prepared.

30 ml (17.48 g) of this catalyst was packed into the same equipment as in Example 1, and heated to 440 to 460°C in a hydrogen stream of 31/hr.
After baking for 80 hours, a dehydration reaction was attempted using a dimer obtained by aldol condensation of cyclohexanone as a raw material using a conventional flow method.

That is, when the raw material feeding rate was 14 mVhr, the furnace temperature was 345°C, and the reaction was carried out under hydrogen flow of 21/hr, the reaction rate was 95% until about 300 hours after the start of the reaction.
%, O-phenylphenol selectivity was only about 90 mo1%, but the reaction performance gradually improved after that, and at 1500 hours after the start of the reaction, the raw material feeding rate was 11.4 ml/
hr, reaction temperature (furnace temperature) 353°C, reaction rate 98%
, the O-phenylphenol selectivity was 93.6 moA%.

Furthermore, at 2500 hours after the start of the reaction, the reaction rate was 97% and the selectivity was 92.8 mo1% at a furnace temperature of 370° C. and a raw material feed rate of 10.5 ml/hr.

On the other hand, when catalyst calcination was carried out at 340 to 360°C for 10 hours, the results were almost the same as above until about 700 hours after the start of the reaction, but the reaction results at 1500 hours after the start of the reaction were Input rate: 9 ml/hr, reaction temperature (furnace temperature): 372°C, reaction rate: 93.1 moA%, 20% after the start of the reaction
At the 00th hour, the raw material feed rate was 7-5 ml/hr.
Even at the N reaction temperature of 395°C, the reaction rate was 88% and the selectivity was 91mo.
It was clear that the catalyst life was increased by firing at 440 to 460°C for 80 hours.

Example 4 Alumina sol manufactured by Nichido Kagaku (alumina content 9.98wt)
%) and Snowtex (silica sol manufactured by Nikki Kagaku Co., Ltd., silica content 20.9 wt%), the water was evaporated on a hot water bath, and silica-alumina with silica:alumina = 1:11 (weight ratio) was mixed. After adjusting the particle size to 8-16 mesh, air circulation (5-71/
hr).

This carrier (BET surface area 335 m'/g, pore volume 0.
78 m1/g) and 2.
5wt%Pt-0, 1wt%Ir-8wt%KNO3-
A supported catalyst was prepared.

This catalyst was heated for 600 minutes under air flow of 0.5 to Il/hr.
The mixture was calcined at ~630°C for 36 hours, and the mixture of P-cyclohexylphenol and 0-cyclohexylphenol was dehydrogenated in the same manner as in Example 2 (the same raw materials as in Example 2 were used).

Further, the cyclohexanone dimer was dehydrogenated in the same manner as in Example 3.

In addition, for comparison, the catalyst (unfired product) was
An experiment was conducted using a catalyst that was calcined at 350 to 360° C. for 10 hours in a nitrogen flow of 31/hr and then calcined for 5 hours at 350° C. in a hydrogen flow of 31/hr.

The experimental results are shown in Table 1.

In addition, in the experiment, the phenylphenol content in the reaction product should be at least 85 wt% (90 wt% as much as possible).
% or more), and as soon as the phenylphenol content decreases, increase the reaction rate or reduce the feed rate of raw materials to maintain the phenylphenol content at the specified value. I went.

Example 5 γ-Alumina pellet manufactured by Catalysts and Chemicals (φ1.5 mm)
, a molded product with a length of 3 to 5 mm, with a BET surface area of 2677 m'
/ g, pore volume 0.7 ml) was left in the air without sealing for about 2 years and was used as a carrier, and 0.5 wt%Pt-0,2wtIr-3wt was prepared in exactly the same manner as in Example 1.
% NaOH-γ-alumina catalyst was prepared.

When this catalyst is used as is and when 530 to 560℃
When fired for 30 hours in the air (without air circulation),
and 560-590℃ under air flow of 3-41/hr
The results shown in Table 2 were obtained by comparing the results of firing for 20 hours.

The dehydrogenation reactions included a dehydrogenation reaction of O-cyclohexylphenol and a dehydrogenation reaction of cyclohexanone dimer.

Claims (1)

[Scope of Claims] 1. A carrier made of at least one selected from r-alumina and silica-alumina is brought into contact with an aqueous solution of chloroplatinic acid or an aqueous solution containing chloroplatinic acid and iridium chloride to produce chloroplatinic acid. Alternatively, a Pt-alkali carrier catalyst or a Pt-alkali carrier catalyst obtained by adsorbing chloroplatinic acid and iridium chloride on a carrier, drying it, reducing it with hydrogen, and then contacting it with an aqueous alkali solution to support an alkali.
C1 represented by the following general formula, characterized in that the -Ir-alkali-supported catalyst is calcined at 420 to 650°C.
2. A method for producing a catalyst for producing phenylphenol by subjecting an oxygen-containing compound to gas-phase catalytic dehydrogenation. (In the formula, at least two or more methylene groups are present in at least one of rings A and B.) 2. Claim 1 in which hydrogen reduction is carried out at 300 to 400°C for 3 to 48 hours. Section method. 3 As a carrier, BET surface area control 0-350, pore volume 0. 5 ~ 0. 9 5ml/g, iron content F
3. The method of claim 1 or 2, wherein r-alumina containing less than 0.5% by weight of e203 or commercially available r-alumina for use as a support for indirect deflow catalyst is used. 4 As a carrier, the BET surface area is 200 to 400
7 g, a pore volume of 0.5 to 0.95 ml/g, a synthetic silica-alumina containing less than 0.5% by weight of iron as Fe2O3 and a silica content of less than 10% by weight. The method of item 1 or item 2. 5 Na or K hydroxide, carbonate as alkali,
5. The method of claim 1, 2, 3, or 4, which uses a compound that can be converted into an oxide during the catalyst production process, such as bicarbonate, formate, acetate, or nitrate. 6. Claim 1, wherein the amount of alkali supported is 1 to 10% by weight of the catalyst weight as the alkali metal oxide,
The method of paragraph 2, paragraph 3, paragraph 4 or paragraph 5. 7 The amount of Pt supported is 0.3 to 3.0% of the weight of the catalyst as metal.
7. The method of claim 1, 2, 3, 4, 5, or 6, wherein the amount is 0% by weight. 8 Claims 1, 2, 3, and 4 in which the amount of Ir supported is 0 to 0.5 times by weight the amount of Pt as a metal.
The method of paragraph 5, paragraph 6, or paragraph 7. 9. The method according to claim 1, 2, 3, 4, 5, 6, 7, or 8, in which firing is performed for 3 to 100 hours under air circulation. . 10 The firing temperature was 520 to 620°C, and the firing time was 1
The method of claim 1, 2, 3, 4, 5, 6, 7, 8, or 9, wherein the duration is 0 to 50 hours. 11 Claims 1, 2, and 3, wherein the C1□ oxygen-containing compound is a dimer obtained by aldol condensation of 0-cyclohexylphenol or cyclohexanone.
The method of paragraph 4, paragraph 5, paragraph 6, paragraph 7, paragraph 8, paragraph 9, or paragraph 10.