JP2637812B2 - Method for producing phenol - Google Patents

Description

The present invention relates to a method for producing phenol by catalytic dehydrogenation of cyclohexanol and / or cyclohexanone,
More specifically, the present invention relates to a method for producing phenol having high activity, high selectivity and long catalyst life.

[Conventional technology]

A method of catalytically dehydrogenating cyclohexanol, cyclohexanone, or the like and converting it to phenol has been known for a long time. As a catalyst, a catalyst in which a noble metal component such as platinum is supported on activated carbon is well known.

U.S. Pat. No. 3,580,970 describes a method using a catalyst comprising a Group VIII metal component (nickel, platinum, etc.) and tin, and a catalyst to which chromium and an alkali metal sulfate are added.

[Problems to be solved by the invention]

However, the former catalyst is industrially disadvantageous because it uses an activated carbon carrier which is extremely difficult to regenerate and contains an expensive noble metal component such as platinum. Further, the latter catalyst containing no noble metal has not reached an industrially satisfactory level, such as insufficient activity and selectivity and a large decrease in activity over time.

An object of the present invention is to solve the problems in the conventional method for producing phenol and to provide a method for producing phenol that can produce phenol with high activity and high selectivity and has a long catalyst life.

[Means for solving the problem]

The present invention provides a method for producing phenol by catalytic dehydrogenation of cyclohexanol and / or cyclohexanone in the presence of a nickel- and tin-containing catalyst, characterized in that the catalyst further contains an alkali metal carbonate. The method of the present invention can dehydrogenate with high activity and high selectivity,
Phenol can be efficiently produced, and the decrease in activity of the catalyst over time can be significantly reduced.

The catalyst used in the present invention has an alkali metal carbonate as an essential component in addition to the nickel component and the tin component,
Usually, these components can be used by being contained in a refractory inorganic carrier. Here, the term "fire resistance" refers to the property of sufficiently withstanding the regeneration temperature when the catalyst of the present invention is regenerated at a high temperature.

Examples of such a carrier include silica, silica / magnesia, titania, silicon carbide, and diatomaceous earth, and silica is particularly preferably used. The inorganic carrier preferably has a specific surface area of 1 m ² / g or more and 350 m ² / g or less and exhibits neutral to weak alkalinity.

The content of the catalyst component is 2 to 20% by weight, more preferably 5 to 15% by weight, as the nickel metal, more preferably 5 to 15% by weight, and the tin component is 10 to 150% by weight of the nickel metal as the tin metal. More preferably, 50 to 100% by weight, and the alkali metal carbonate is used in an amount of 0.5 to 20% by weight, preferably 1 to 10% by weight based on the carrier.

Examples of the alkali metal carbonate include lithium, sodium, potassium, rubidium, and cesium carbonates, and sodium or potassium carbonate is particularly preferable. If the amount of these carbonates is less than the above-mentioned ratio, the selectivity of phenol is inferior. If the amount is large, the activity tends to decrease, and the production of heavy substances increases.

Next, a typical method for preparing the catalyst of the present invention will be described. First, a carrier is impregnated with a solution of nickel, tin salt, for example, water such as nickel nitrate or tin chloride, alcohol, acetone or the like, then dried, and calcined preferably at a temperature of 300 to 500 ° C. Next, it is impregnated with an alkali metal carbonate or bicarbonate solution and then dried. It is then prepared by a reduction treatment in a hydrogen stream, preferably at a temperature of 300 to 450 ° C.

The impregnation of nickel and tin may be carried out quasi-separately, but it is preferable to carry out the impregnation simultaneously using a mixed solution. The addition of the carbonate or bicarbonate of the alkali metal is preferably carried out after supporting the nickel component and the tin component and calcining them. The hydrogen reduction treatment may be performed directly before the reaction in the dehydrogenation reactor.

In the present invention, the reaction temperature in the catalytic dehydrogenation reaction is:
250 ° C to 450 ° C, preferably 300 to 400 ° C, reaction pressure is 0.5
The feed rate of cyclohexanol and / or cyclohexanone is 0.1 to 10 atm, preferably 1 to 5 atm.
It is preferably carried out at a volume hourly space velocity (LHSV) of up to 10 times / hour, preferably 0.2 to 5 times / hour.

Since the hydrogen partial pressure affects the stability of the catalyst, hydrogen is supplied to the reactor in a molar ratio of (hydrogen) / (cyclohexanol and / or cyclohexanone) of 0.5 to 10, preferably 1 to 5. Is desirable.

〔The invention's effect〕

According to the method of the present invention, cyclohexanol and / or cyclohexanone can be converted to phenol with high conversion and high selectivity, so that the phenol yield per pass is high and the load of purification and separation can be reduced. In addition, the catalyst has little decrease in activity over time, so it can withstand long-term use.
The industrial advantage of the deteriorated catalyst is extremely large because its activity and selectivity can be easily recovered by combustion regeneration.

Examples Hereinafter, the present invention will be described specifically with reference to Examples.
The present invention is not limited to this. The conversion and selectivity in Examples and Comparative Examples are as follows.

Here, A: the total number of moles of cyclohexanol and cyclohexanone in the raw material liquid.

B: Total number of moles of cyclohexanol and cyclohexanone in the reaction solution.

Here, A and B are the same as above.

Example 1 A solution obtained by dissolving 8 g of nickel nitrate hexahydrate and 2.5 g of tin chloride dihydrate in 8 g of alcohol and further dissolving in 15 g of distilled water was added to a commercially available spherical silica (5 to 10 g) at room temperature. It was absorbed in 20 g of a mesh, a specific surface area of 300 m ² / g, and a pore volume of 1.07 cc / g), then dried at 110 ° C. overnight, and calcined in air at 500 ° C. for 10 hours. Next, a solution of 0.4 g of potassium carbonate dissolved in 23 g of distilled water was absorbed into the calcined product, dried at 110 ° C. for 4 hours, and calcined at 500 ° C. for 4 hours. This catalyst contained 8.1% by weight of nickel metal with respect to the carrier, 81% by weight of nickel metal with respect to the nickel metal, and 2% by weight of potassium carbonate with respect to the carrier (catalyst A).
Into a stainless steel reaction tube (20 mmφ x 300 mm length)
The mixture was heated to 400 ° C. in a heating furnace, and subjected to a hydrogen reduction treatment for 4 hours while passing hydrogen at a rate of 10 / Hr. Next, cyclohexanol was supplied at a rate of 5 ml / Hr by a metering pump, and hydrogen was supplied at a molar ratio of 4 mol to cyclohexanol.
At a reaction temperature of 350 ° C., a catalytic dehydrogenation reaction was performed. The results are shown in Table 1.

Comparative Example 1 Example 1 except that potassium carbonate was not supported.
A catalyst was prepared in the same manner as in (Catalyst B). Using this catalyst, a catalytic dehydrogenation reaction of cyclohexanol was carried out in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 2 A catalyst was prepared in the same manner as in Example 1 except that potassium sulfate was used instead of potassium carbonate (catalyst C). Using this catalyst, a catalytic dehydrogenation reaction of cyclohexanol was carried out in the same manner as in Example 1. The results are shown in Table 1.

Example 2 As a result of performing a catalytic dehydrogenation reaction of cyclohexanone in the same manner as in Example 1 using the catalyst A prepared in Example 1,
The conversion of cyclohexanone was 98.8%, and the phenol selectivity was 99 mol%.

Example 3 Example 1 using spherical silica (5 to 10 mesh, specific surface area 180 m ² / g, pore volume 1.05 cc / g) and potassium carbonate 1.0 g
A catalyst was prepared in the same manner as in (Catalyst D). This catalyst contained 8.1% by weight of nickel metal with respect to the carrier, 81% by weight of tin metal with respect to nickel metal, and 5% by weight of calcium carbonate with respect to the carrier. Using catalyst D, catalytic dehydrogenation of cyclohexanol was carried out in the same manner as in Example 1.

 The results are shown in Table 2.

After 35 hours of contact, the contact was regenerated in air at 450 ° C., then reduced, and the catalyst was used in Example 1 using the catalyst.
As a result of performing catalytic dehydrogenation under the same conditions as above, the conversion rate was 98%, the phenol selectivity was 99.2%, and the initial activity and the selectivity were the same.

Comparative Example 3 Contact adjustment was performed in the same manner as in Example 3 except that potassium carbonate was not added. Table 3 shows the results of catalytic dehydrogenation using the catalyst in the same manner as in Example 3.

Example 4 The result of performing a catalytic dehydrogenation reaction in the same manner as in Example 1 by using catalyst D but using cyclohexanone as a raw material under the conditions of LHSV ≒ 1 hr ⁻¹ , reaction temperature of 375 ° C., and hydrogen / cyclohexanone molar ratio of 4.5. , Conversion rate 96.7%, phenol selectivity 99.1
%Met.

Example 5 Example 1 except that potassium carbonate was contained at 0.5% by weight.
The same catalyst as in Example 1 was prepared, and the catalytic dehydrogenation of cyclohexanol was carried out in the same manner as in Example 1.
The phenol selectivity was 98.6% with 98.6%.

Example 6 In the same manner as in Example 1, 9% by weight of nickel metal relative to the carrier and 78% of tin metal relative to nickel metal were used.
A catalyst was prepared in which silica was supported on silica at 10% by weight and potassium carbonate as a weight% and potassium carbonate, and catalytic dehydrogenation of cyclohexanol was carried out in the same manner as in Example 1. As a result, the conversion was 91.5% and the phenol selectivity was 99.1%.

Example 7 A catalyst was prepared in the same manner as in Example 1 except that sodium carbonate was used instead of potassium carbonate. As a result of catalytic dehydrogenation of cyclohexanol in the same manner as in Example 1 using this catalyst, the conversion was 97.8% and the phenol selectivity was 98.7%.

Claims (3)

(57) [Claims] 1. A process for producing phenol by dehydrogenating cyclohexanol and / or cyclohexanone in the presence of a nickel- and tin-containing catalyst, characterized in that the catalyst contains an alkali metal carbonate. Production method 2. The method according to claim 1, wherein the alkali metal is sodium or potassium metal. 3. The method according to claim 1, wherein the alkali metal is sodium or potassium metal, and the content of the carbonate is 1 to 10% by weight with respect to the carrier.