JPS5835094B2 - 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 selected from γ-alumina and silica-alumina with an aqueous solution of chloroplatinic acid or an aqueous solution containing chloroplatinic acid and iridium chloride. , adsorbed on a carrier of chloroplatinic acid or chloroplatinic acid and iridium chloride, dried, then reduced with hydrogen, and electrodialyzed to remove ionic substances such as CI. The present invention relates to a method for producing a gas phase catalytic dehydrogenation catalyst for producing a phenolic compound, which comprises bringing a dialysate into contact with an aqueous alkali solution to support an alkali.

Phenol and naphthol are extremely important chemicals, and various manufacturing methods have been proposed, but the dehydrogenation method is also attracting attention as a pollution-free manufacturing method that does not produce co-products.
In addition to the production of α-naphthol, phenol synthesis by dehydrogenation of cyclohexanol and/or cyclohexanone has also reached the stage of industrialization.

In addition, the demand for phenylphenols as raw materials for organic fine chemicals has increased rapidly recently, 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 satisfactory has not been found.

The present inventor searched for a method for producing phenylphenol using a dehydrogenation method, and found that a pt-alkali-γ-alumina (a certain L is a synthetic silica-alumina with a high alumina content) catalyst has an excellent ability to selectively produce phenylphenol. Heading,
Obtained patents (Japanese Patent Nos. 804485 and 8156)
No. 09, No. 857162).

This method has many advantages over the conventional method, so half-speed O
- It has been used for the industrial production of phenylphenol and is still in operation, but as a result of a more detailed study, the only drawback of this method is that even with almost the same physical properties, it is impossible to analyze it at present. It has become clear that catalyst life varies widely depending on factors.

As a result of various studies aimed at obtaining a catalyst with good activity and long life with good reproducibility, the present inventor learned that adding a small amount of Ir was effective and filed a patent application (Japanese Patent Application Laid-Open No. 51-14924).
8) As a result, it seemed that the production of phenylphenol by the dehydrogenation method was almost completed, but when we carried out an even longer life test, we found that when γ-alumina or the like that had been left in the air for a long time was used as a carrier, Physical properties of r-alumina and E
Although there was no change in the surface condition examined by SCA and IMA, we found that only the catalyst life was significantly reduced, so we developed an excellent dehydrogenation catalyst using this tx state contact. The present invention was achieved as a result of various studies on methods for preparing .

γ-alumina or synthetic silica alumina with an alumina content of 90% or more (the synthetic silica alumina used here is BE)
T surface area 200-400 m/r and pore volume 0.4
~0.95 ml/f.

) is said to fluctuate in catalyst performance due to slight changes in temperature or pH during production, and it is considered extremely difficult to maintain perfect reproducibility.

However, even when measured using the current highest level 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 data obtained from physical property values and instrumental measurements.

Therefore, the only way to develop a long-life catalyst is through trial and error, and the results of the method of the present invention are no different from that. However, the catalytic electrodialysis effect during phenol synthesis is surprising, and There have been many examples in which catalysts that have a lifetime of only 100 hours or less in the case of Shina L. have a lifetime of several thousand hours by electrodialysis (see Examples).

According to a detailed study by the present inventor, a dehydrogenation catalyst that is effective in selectively producing phenols has a BET surface area of 150
~350m/P, pore volume 0.4~0, 95ml/
? Therefore, it is preferable to use γ-alumina as a carrier, which has a low iron content (0.5% by weight or less), and mixing silica in an amount of 10% by weight or less often improves the carrier performance.

That is, the carrier can be γ-alumina for carriers with a relatively large pore volume or synthetic silica alumina with an alumina content of 90% or more.

As described in the above-mentioned patent obtained by the present inventor, the catalyst composition is that the amount of Pt supported is 0.3 to 3.0% by weight, the amount of Ir supported is 0 to 0.5 times the amount of Pt supported, and as an alkali. is N
Oxides of a and K are preferred, and the amount of these supported is preferably about 1 to 10% by weight of the weight of the catalyst.

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, the practical range of PT loading is 0.1 to 5.
．． It can be said that it is 0% by weight, but more realistically it is 0.3 to 3.0%.
It can be said that the amount is about 1.0 to 2.0 weight %, and the optimum range is about 1.0 to 2.0 weight %.

The alkalis used in the method of the present invention 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
γ-alumina or 1 carrying t or pt and Ir
A catalyst supporting the required amount of alkali may be prepared by contacting with silica-alumina containing 0% by weight or less of silica, and suitable compounds for this purpose include Na or K hydroxides, carbonates, bicarbonates. There are salts, formates, acetates, nitrates, etc., and hydroxides and carbonates are particularly suitable in terms of price 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 weak or if the compound to be dehydrogenated is susceptible to carbonium ion reactions, the amount of alkali added will vary depending on the type of carrier used and the compound to be dehydrogenated. In many cases, good results are obtained when the value is increased somewhat.

Although there are some variations, generally 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 add a certain amount.

If the amount added is too small, the acidity of the catalyst will not be neutralized.
Side reactions such as decomposition and dehydration 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 the catalyst according to the method of the present invention:
Platinum or platinum and iridium are supported in the form of a salt on a carrier, and then hydrogen-reduced to make most of the salt in a metallic state, followed by supporting an alkali. Hydrogen reduction at 400'C is most desirable.

Although there are many cases where the hydrogen reduction temperature is 300°C or lower or 400°C or higher, there is no major problem; however, at 300°C or lower, the reduction time becomes long, and at 200°C or lower, sufficient reduction becomes difficult.

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.

Electrodialysis after hydrogen reduction is the core operation of the method of the present invention, but this method can be performed using a common semipermeable membrane, such as a cellulose acetate membrane.
You can use the normal electrodialysis method using a dialysis membrane and carbon or metal electrodes. Electrodialysis can usually be continued for 2 to 3 days, but if a large decrease in current value is observed before then,
Even if dialysis is terminated at that point, there is almost no difference in the performance of the obtained catalyst.

Even if electrodialysis is continued for a week or more, the performance of the resulting catalyst will not deteriorate, but if it continues for an unnecessarily long period of time, no improvement in catalyst performance will be observed. Continuation of the above is not desirable.

That is, the time required for electrodialysis varies somewhat depending on the type of carrier, etc., but generally it may be carried out for one day to one week, and it is customary to carry out it for two to three days.

Electrodialysis is generally known as a method for easily removing electrolyte ions that are difficult to remove, and it is clear that Cl ions are reduced by electrodialysis in the method of the present invention as well.

There are many similarities between the platforming method, a well-known method for obtaining aromatic compounds by cyclodehydrogenation of hydrocarbons, and the method of the present invention, but in the case of platforming, Cl ions present in the catalyst However, from the above results, the presence of Cl ions seems to have a negative effect when phenols are obtained by dehydrogenating oxygen-containing compounds.

However, platinum-alumina catalysts prepared from C1-containing red platinum salts, such as Pt(N)(3)2(NO2)2-, as starting materials have been used as dehydrogenation catalysts for oxygenated compounds for the purpose of producing phenols. This is completely inappropriate, and in some cases even active addition of chlorine is effective, so the behavior of chlorine in this catalyst system is extremely subtle, and the reason why electrodialysis is effective is not fully clear. .

Furthermore, we have not found any examples of catalyst life being increased by electrodialysis, and it is difficult to imagine from conventional literature that the life of a dehydrogenation catalyst for the purpose of producing phenols would be greatly increased by electrodialysis. Even for experts in this field, it is completely impossible to predict that electrodialysis will increase catalyst life.

The dehydrogenation catalyst prepared by the method of the present invention is effective for dehydrogenating oxygen-containing hydrocarbons having a cyclic structure from the beginning to obtain corresponding phenols, and specifically, from cyclohexanol and/or cyclohexanone. Synthesis of phenol, synthesis of O-phenylphenol from a dimer obtained by aldol condensation of O-cyclohexylphenol and/or cyclohexanone, synthesis of p-phenylphenol from p-cyclohexylphenol, synthesis of α-naphthol from α-tetralone, synthesis of cyclohexanone It is effective for the synthesis of 2,6-diphenylphenol from the trimer obtained by aldol condensation.

However, it is not effective in the reaction of cyclodehydrogenating oxygen-containing chain compounds to obtain phenols.

When producing a dehydrogenation catalyst by the method of the present invention, when using a certain type of carrier, the performance can be significantly improved by calcining the carrier in air at a temperature of about 550 to 630°C before supporting chloroplatinic acid. The matter is acknowledged.

The main reason for this is presumed to be the burning and removal of organic matter remaining in the carrier (part of the organic matter used in the manufacture of the carrier), which is completely different from the firing effect that the present inventor has filed separately.

Experimental results have shown that when long-life catalysts prepared by electrodialysis are fired, their lifespans are drastically reduced. can be said to fluctuate.

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 Catalyzed or industrially made γ-alumina pellets (molded product with a diameter of 1.5 mm and a length of 3 to 5 mm, with a BET surface area of 226 m 1/2,
A carrier with a pore volume of 0.85 mJ/r) was thoroughly degassed and water was added to prevent the destruction of alumina during water use.
547r and IrCl4.H2O0,074f? Add 50ml of distilled water dissolved in it, and add 50ml of distilled water, stirring occasionally
The noble metal salt was sufficiently adsorbed onto the carrier by standing for a period of time.

After drying this catalyst in a 110'C electric dryer 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.

This catalyst (21,02) had a commercially available special grade caustic force I71.2s.
40 ml of distilled water containing ' was added, and caustic potash was adsorbed by the immersion method.

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

This catalyst (1,0 wt% Pt-0,2 wt% Ir5 wt% KOH-r-alumina) 30 mJ (17,52)
was filled into the catalyst-packed part of a molybdenum glass reaction tube with an inner diameter of 2'2 nm and a length of 800 mm, and placed in a tubular electric furnace to perform a dehydrogenation reaction of O-cyclohexylphenol using a normal 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 at a rate of 373/h.
The reactor temperature was maintained at 350° C. (the lowest temperature of the catalyst layer during the reaction was 325 to 327° C.).

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 then placed in a 3% silicone XE-60-Chromosolp 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 higher and the 0-phenylphenol selectivity was maintained at 95 mol% or higher until the time elapsed, but the reaction rate gradually decreased after that, so the reaction temperature was increased accordingly to maintain the reaction rate at 90% or higher. I made it.

As a result, the reaction temperature was 402 at 2000 hours after the start of the reaction.
℃, reaction rate 95%〇-phenylphenol selectivity 94
The mole % is shown.

However, after leaving the carrier in air for about two years without sealing, a catalyst was prepared in exactly the same manner as above, and when the dehydrogenation reaction of 0-cyclohexylphenol was carried out in exactly the same manner as above, the reaction started. Immediately after, the reaction rate was 99% and the 0-phenylphenol selectivity was 78 mol%, but at 30 hours, the reaction rate was 75% and the 0-phenylphenol selectivity was 78%.
The selectivity decreased to 9 mol %, 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% Pt-
A 0.2% by weight Ir-degraded γ-alumina catalyst was electrodialyzed and then a KOH-supported catalyst was prepared in the manner described above.

Electrodialysis was performed using a conventional method using a cellulose acetate membrane as a diaphragm and a carbon plate as an electrode.
It has a volume of 'rL×8CrIL×16CrrL.

Each chamber is filled with distilled water, and the precious metal-supported γ-alumina in a gauze bag is suspended in the center of the dialysis section (center).
Electrodialysis was performed by applying a DC voltage of 0V.

The current flowed from the beginning to only about 50 rrLA, and then gradually decreased to about 20 mA after 30 hours of electrodialysis.

After that, the electrodialysis was maintained at about 20rrLA, so the electrodialysis was stopped after 70 hours, and the catalyst was prepared by washing with distilled water and immersed in a solution containing a predetermined amount of alkali. Three hours after the start, the raw material feed rate was 13.5 mJ/hr, the furnace temperature was 333°C, the reaction rate was 100%, and the 0-phenylphenol selectivity was 81.
However, the reaction performance gradually improved after that, and at 300 hours after the start of the reaction, the raw material feed rate was 9.6%.
ml/hr, furnace temperature 348°C, reaction rate 99%, selectivity 93.8 mol%, and at 1500 hours, raw material feed rate 9.9ml/hr, furnace temperature 376°C, reaction rate 97.
1% and a selectivity of 93 mol%, and even at the 3000th hour, the reaction rate was 94% and the selectivity was 92.4 mol% at a raw material feed rate of 8.4 m//hrs and a furnace temperature of 401°C.

When Ir is not added in an experiment using an electrodialysis effect medium,
The results were better than when Ir was added, and even at the 3000th hour, the raw material feed rate was 8.8 ml/hr.

At a furnace temperature of 398°C, the reaction rate was 93% and the selectivity was 94.1 mol%.

From this result, it is estimated that the effect of Ir addition is almost k in the case of electrodialysis.

In addition, when using a catalyst without adding Ir without electrodialysis,
Even immediately after the start of the reaction, the reaction rate was 53% and the 0-phenylphenol selectivity was 72 mol% (raw material feed rate 9 ml/hr
, the furnace temperature was only 350° C.), and it is clear that the electrodialysis effect is tremendous regardless of whether Ir is added or not.

Example 2 Catalyzed R-alumina pellets made by Kogyo (a molded product with a diameter of 1.5 mm and a length of 3 to 5 mm, with a BET surface area of 320 ml?
, pore volume 0.68 m1/f/, SiO2 content 1.91
(wt%, containing 0.03 wt% Fe as Fe2O3)
was calcined for 20 hours while passing air at a flow rate of 3 to 51:/hr as a carrier, and in the same manner as in Example 1, 1 wt% Pt-5 wt% KOH-γ-alumina catalyst, and 1 A wt% pt-3 wt% KOH-gamma-alumina catalyst was prepared and compared between an electrodialyzed product and a catalyst without electrodialysis.

Electrodialysis was performed in exactly the same manner as in Example 1, and the dialysis time was 48 hours.

0-cyclohexylphenol, op-mixed cyclohexylphenol (synthesized by reaction of phenol and cyclohexene, 0-cyclohexylphenol content 57%), dimer obtained by aldol condensation of cyclohexanone, cyclohexanol, and α The dehydrogenation results of -tetralone are shown in Table 1.

In each experiment, 30 ml of catalyst was used, and for the dehydrogenation of 0-cyclohexylphenol and mixed cyclohexylphenol, 3% by weight KOH was supported, and for the other products, 5% by weight K was used.
It was carried out in the same manner as in Example 1 using an OH-supported product,
When producing phenylphenol and α-naphthol, decompose the target product in the product at a concentration of 85% by weight or more (90% by weight or more if possible), and when producing phenol, the target product concentration in the product is 60% by weight or more (as high as possible at the beginning of the reaction). Product selectivity 5% by weight
The reaction was carried out while appropriately raising the temperature and adjusting the feed rate of raw materials so that the following conditions were achieved.

Furthermore, since mixed cyclohexylphenol has a high melting point, the storage tank and supply pump were kept at around 100°C.

Since p-phenylphenol and α-naphthol have high melting points (·, when dehydrogenating the mixed cyclohexylphenol and α-tetralone produced by these, the product collection trap was heated to around 100°C with a ribbon heater.

*l A: Use a catalyst that does not undergo electrodialysis.

- Dehydrogenation reaction of cyclohexylphenol B using two electrodialysis catalysts.

- Dehydrogenation reaction of cyclohexylphenol C: Dehydrogenation reaction of mixed cyclohexylphenol using a catalyst without electrodialysis D: Dehydrogenation reaction of mixed cyclohexylphenol using an electrodialysis catalyst E: Cyclohexanone using a catalyst without electrodialysis F° Dehydrogenation reaction of cyclohexanone dimer using an electrodialysis catalyst G: Dehydrogenation reaction of cyclohexanol using a non-electrodialysis catalyst H: Dehydrogenation reaction of cyclohexanol using an electrodialysis catalyst I: Dehydrogenation reaction of α-tetralone using a catalyst without electrodialysis J: Dehydrogenation reaction of α-tetralone using an electrodialysis catalyst *2 Selectivity of target phenolic compound (mol%) *3 Furnace temperature (℃) *4 LH3V=liquid space velocity (cc/cc/h
r ) *5 In addition, decomposition products (benzene, etc.) were produced with a selectivity of 6.5% by weight, and the decomposition product production rate further increased, so the reaction was stopped at 165 hours (decomposition product selectivity at this time 9.8% by weight).

Example 3 Sumitomo activated alumina KHA-24 (φ2 to 4 spherical, B
ET surface area 150-180 rrl/f? , hosogo volume 0
．． 5 to 0.6 ml/ft) as a carrier, and 2.5 wt% Pt - 7.0 wt% N in the same manner as in Example 1.
A 2 COs-activated alumina catalyst was prepared, and 0-cyclohexylphenol and 1 monomer of cyclohexanone (
We conducted a dehydrogenation reaction of α-tetralone (aldol condensate), α-tetralone, and cyclohexanone trimer (aldol condensate), and attempted to compare electrodialysis catalysts and catalysts without electrodialysis.
The results shown in Table 2 were obtained.

The electrodialysis conditions and standards of the life test method were the same as in Example 2.

*1 A: Dehydrogenation reaction of O-cyclohexylphenol using a catalyst without electrodialysis B: 0 using an electrodialysis catalyst
- Dehydrogenation reaction of cyclohexylphenol C: Dehydrogenation reaction of cyclohexanone trimer using a catalyst without electrodialysis D: Dehydrogenation reaction of cyclohexanone trimer using an electrodialysis catalyst E: α using a catalyst without electrodialysis −
Tetralone dehydrogenation reaction F: α using electrodialysis catalyst
- Dehydrogenation reaction of tetralone C: Dehydrogenation reaction of cyclohexanone trimer using a catalyst without electrodialysis H: Dehydrogenation reaction of cyclohexanone trimer using an electrodialysis catalyst Selectivity of the target phenolic compound (molar %) Furnace temperature (°C') LH3V-Liquid hourly space velocity (cc/cc/hr) Example 4 R-Alumina pellet manufactured by Catalysts and Chemicals (φ1.5 mm, length 3-51nrIL molded product, BET surface area 267rr
l/? , pore volume 0.7ml/f? 1.5% by weight Pt -5% by weight - in exactly the same manner as in Example 1 using a carrier that had been left in the air without sealing for about 2 years.
A NaOH-γ-alumina catalyst was prepared, and a comparison was made between an electrodialyzed product and a case without electrodialysis, and the results shown in Table 3 were obtained.

In addition, electrodialysis was performed for 5 days, and the life test method was performed according to the same standards as in Example 2.

*l A: Dehydrogenation reaction of 0-cyclohexylphenol using a L catalyst without electrodialysis B: Dehydrogenation reaction of 0-cyclohexylphenol using an electrodialysis catalyst C: Dehydrogenation of cyclohexanol using a catalyst without electrodialysis Reaction D: Dehydrogenation reaction of cyclohexanol using electrodialysis catalyst *2 Selectivity of target phenolic compound (mol%) *3 Furnace temperature (℃) *4 LH8V = liquid hourly space velocity (cc/cc/hr
) Example 5 Catalyst (γ-alumina pellets manufactured by d Kogyo (φ1.5 diameter, length 3-5 mm molded product, BET surface area 198 m/fl, pore volume 0.88 mt/l) was used as a carrier, Example 0.7 wt% Pt - 3.5 wt% KOH by exactly the same operation as 1.
-γ-Alumina catalyst and 0.7% by weight *EPt -0
, 2 wt% Ir-3, 5 wt% KOH catalyst was prepared, and 0
- The effect of the electrodialysis catalyst during the cyclohexylphenol dehydrogenation reaction was investigated and the results shown in Table 4 were obtained.

In addition, in Experiment B in Table 4, the 00-phenylphenol content in the product was maintained at 90% by weight or more even after 5000 hours (LH8V0.33).

1 A: 0- using Ir-free non-electrodialysis catalyst
Dehydrogenation reaction of cyclohexylphenol B: Dehydrogenation reaction of 0-cyclohexylphenol using an Ir-free electrodialysis catalyst C: Dehydrogenation reaction of 0-cyclohexylphenol using an Ir-containing non-electrodialysis catalyst D: Ir-free dehydrogenation reaction Dehydrogenation reaction of o-cyclohexylphenol using electrodialysis catalyst containing *2 Selectivity of o-phenylphenol (mol%) *3
Furnace temperature ("C) *4 LH3V=Liquid space velocity (cc/cc/hr
) Example 6 After mixing Nissan Chemical's alumina sol (alumina content 9.98% by weight) and Snowdex (8san Chemical's silica sol, silica content 20.9% by weight), the water was evaporated on a hot water bath. , prepared silica-alumina with silica:alumina=1:11 (weight ratio), made the particle size 8-16 mesh, and then air-circulated (5-71
:/hr: Baked below.

(BET surface area 335 ml?, fine pore volume 0.78
at/t) Using this carrier, a 2.5 wt% Pt-8 wt% KNO3-carrier catalyst (electrodialyzed product and non-electrodialyzed catalyst were prepared) in exactly the same manner as in Example 1.

This catalyst was heated at 350° C. under nitrogen flow of 0.5 to 11/hr.
After calcination at ~370°C for 36 hours, various compounds were dehydrogenated in exactly the same manner as in Example 2, and electrodialyzed products and non-electrodialyzed catalysts were compared.

Claims (1)

[Scope of Claims] 1. A carrier made of at least one selected from γ-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, it is adsorbed onto a carrier of chloroplatinic acid and iridium chloride, dried, then reduced with hydrogen, electrodialyzed to remove ionic substances such as CI, and the resulting dialyzed product is dissolved in alkaline aqueous solution. The saturated carbon six-membered ring structure present in oxygenated hydrocarbons having a phenolic ring structure is dehydrogenated by contacting with alkali to support an alkali, and the phenols having the corresponding aromatic ring are A method for producing a catalyst for production. 2. The method according to claim 1, in which hydrogen reduction is carried out at 300 to 400"C for 3 to 48 hours. 3. As a support, γ alumina containing 0.5% by weight or less as Fe2O3 with a BET surface area of 1 to 350. 4. The method according to claim 1 or 2, in which the support is a synthetic silica having a BET surface area of 20 to 400 and containing less than 0.5% by weight of Fe2O3 and a red silica content of not more than 10% by weight. The method according to claim 1 or 2 using alumina. 5. Na or K hydroxide, carbonate, as alkali.
5. The method according to 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 as metal is 0.3 to 3 of the catalyst weight,
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 00 to 0.5 times the amount of pt by weight as metal.
The method of paragraph 5, paragraph 6 or paragraph 7. 9 Claims 1, 2, 3, and 4 in which the phenolic compound is phenol and the substance to be dehydrogenated is cyclohexanol and/or cyclohexanone.
The method of paragraph 5, paragraph 6, paragraph 7 or paragraph 8. 10 Claims 1, 2 and 2, in which the phenolic compound is 0-phenylphenol and the product to be dehydrogenated is a dimer obtained by aldol condensation of 0-cyclohexylphenol and/or cyclohexanone. The method of Section 3, Section 4, Section 5, Section 6, Section 7 or Section 8. 11 Claims 1, 2, 3, and 4, wherein the phenolic compound is p-phenylphenol and the dehydrogenated product is p-cyclohexylphenol,
The method of paragraph 5, paragraph 6, paragraph 7 or paragraph 8. 12 The phenolic compound is α-naphthol,
Claim 1 in which the product to be dehydrogenated is α-tetralone
The method of paragraph 2, paragraph 3, paragraph 4, paragraph 5, paragraph 6, paragraph 7 or paragraph 8.