JP2979675B2 - Method for producing phenol and apparatus for producing phenol - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing phenol by subjecting toluene to gas phase oxidation in the presence of a catalyst, and an apparatus for producing phenol.

[0002]

2. Description of the Related Art Processes for producing phenol, such as the cumene process from benzene via cumene and the dow process from toluene via benzoic acid, have been established and are already practiced on an industrial scale. However, all of these existing processes require two or more steps, and the production equipment and operation are complicated. Therefore, it is desired to establish a simpler one-step synthesis method. There are several known methods of producing phenol from toluene in a single reaction step.For example, a method of reacting oxygen with paraffinic hydrocarbons such as methane in toluene at a temperature of 600 to 900 ° C. (JP-A-47-39037). Further, there has been a method in which toluene and oxygen are reacted at a temperature of 400 to 1000 ° C. in the presence of alcohols (JP-A-52-27730).

[0003]

SUMMARY OF THE INVENTION However, Japanese Patent Application Laid-Open
In the method disclosed in JP-A-47-39037, both the phenol selectivity and the yield (product of the conversion and the selectivity) are not sufficient, and the phenol selectivity is 19.2% at the maximum and the phenol yield is 7.5%. there were. Moreover, continuous operation was difficult because a large amount of tar-like substances was generated, and the reaction tube and the like were blocked due to precipitation of carbonaceous substances and generation of resinous substances.

Also, the method disclosed in Japanese Patent Application Laid-Open No. 52-27730 also has insufficient phenol selectivity and yield, with a phenol selectivity of 22.6% and a phenol yield of 9.3% at the maximum. In addition, since a large amount of by-products such as cresol, benzene, styrene, ethylbenzene, benzaldehyde and tar-like substances are produced, a purification step of the produced phenol is required, which is economically disadvantageous.

The present invention solves the above problems and can be produced in a single reaction step, and can produce phenol from toluene with high selectivity and high yield. An object of the present invention is to provide a method and an apparatus for producing unnecessary phenol.

[0006]

Means for Solving the Problems The present inventors have made intensive studies to achieve the above object, and found that a catalyst containing vanadium oxide on the upstream side was used in producing phenol by gas phase catalytic oxidation of toluene. It has been found that phenol can be produced with a high selectivity and a high yield by using a reactor in which a catalyst containing iron oxide, nickel oxide and a basic compound is disposed downstream, and the present invention has been completed. did.

That is, according to the process for producing phenol of the present invention, in a process for producing phenol by subjecting toluene to gas phase catalytic oxidation, a reaction gas containing toluene is first brought into contact with a catalyst containing vanadium oxide, and then iron oxide and oxide It is characterized by being brought into contact with a catalyst containing nickel and a basic compound.

In the phenol production apparatus of the present invention, when producing phenol by subjecting toluene to gas-phase catalytic oxidation, a reaction gas containing toluene is first brought into contact with a catalyst containing vanadium oxide, and then iron oxide, nickel oxide and The catalyst is characterized by contacting with a catalyst containing a basic compound.

First, among the catalysts used in the present invention, the reaction
Catalyst containing vanadium oxide placed upstream in the vessel
explain about. Here, vanadium oxide is V_TwoO_FiveIn
And V _TwoO_FourEtc. can be included.

[0010] When a catalyst comprising only vanadium oxide is used as a catalyst disposed on the upstream side in the reactor,
It is preferable to add various compounds to the catalyst because a side reaction centering on the combustion reaction of toluene is likely to proceed. Preferred additives are oxides of alkali metals such as lithium, sodium, potassium, rubidium and cesium,
It is sulfate, carbonate, hydroxide or nitrate. In addition, one or more oxides such as magnesium, calcium, strontium, barium, titanium, zirconium, niobium, chromium, molybdenum, tungsten, manganese, tin, phosphorus, and antimony can also be added. The content of these additives in the catalyst is about 0.01
A range of 〜10% by weight is preferred. The content of additives is about 0.01
If it is smaller than the weight percentage, the combustion reaction of toluene takes precedence, and a high phenol selectivity cannot be obtained. When the content of the additive is more than about 10% by weight, the conversion of toluene is reduced.

Further, the above catalyst can be used by being supported on various catalyst carriers. Preferred catalyst carriers include γ-alumina, α-alumina, titanium oxide, silica gel, silicon carbide and the like.

The production of the catalyst can be carried out by a known method. When a carrier is used, for example, an impregnation method can be used. When an aqueous solution is used by the impregnation method, an aqueous solution of a vanadium compound which is water-soluble and can be easily thermally decomposed and converted to vanadium oxide such as ammonium metavanadate or vanadyl oxalate as a raw material of vanadium oxide may be used. In addition, a compound soluble in an organic solvent such as vanadium oxide acetylacetonate can be used by dissolving it in the organic solvent. Various compounds other than vanadium oxide may be added at any time before or after the active ingredient, vanadium oxide is supported on the carrier, or at the time of supporting the vanadium oxide.

The catalyst composition prepared as described above is calcined after drying in air at 90 to 150 ° C. for 12 to 36 hours. The calcination is preferably performed by heating in air or an inert gas such as nitrogen at a temperature of 350 to 700 ° C. for 1 to 10 hours.

Next, a catalyst containing iron oxide, nickel oxide and a basic compound, which is disposed on the downstream side in the reactor, will be described. Here, iron oxide is Fe ₂ O ₃ , which can include Fe ₃ O _4, etc., and nickel oxide is NiO,
Ni ₂ O _{3 and the} like can be included.

The basic compound is preferably an alkali metal or alkaline earth metal compound, such as Li ₂ O, Na ₂ O, K ₂
Oxides or carbonates, hydroxides, nitrates, etc. of alkali metals such as O, Rb ₂ O, Cs ₂ O or MgO, CaO, Sr
Oxides, carbonates, hydroxides and nitrates of alkaline earth metals such as O and BaO.

The content of the basic compound is about oxide equivalent.
The range of 0.05 to 30% by weight is preferred. When the content of the basic compound is less than about 0.05% by weight, the production of CO and CO ₂ increases, and the selectivity of phenol decreases. When the content of the basic compound is more than about 30% by weight, the conversion of toluene decreases.

The ratio of nickel oxide to iron oxide (NiO / Fe ₂ O ₃ ) in the catalyst is preferably in the range of about 0.1 to 10 by weight. If the proportion of nickel oxide is greater than about 10, the production of CO and CO ₂ by complete combustion increases, and the selectivity of phenol decreases. On the other hand, when the proportion of nickel oxide is smaller than about 0.1, the production of benzene is remarkable, and the selectivity of phenol decreases.

The preparation of the catalyst can be carried out by a general preparation method conventionally used for this type of catalyst. For example, nitrates, carbonates, organic acid salts, halides, hydroxides, oxides, and the like of iron and nickel can be used as production raw materials. As a method for mixing iron, nickel and the basic compound, a usual precipitation method, kneading method, impregnation method and the like can be used. For example, the basic compound is mixed with the prepared gel-like mixture of iron hydroxide and nickel hydroxide as it is or in the form of a solution, followed by drying and firing. Further, a basic compound may be mixed in a kneaded product of iron oxide and nickel oxide, or a basic compound may be mixed in a mixed fired product of iron oxide and nickel oxide, and a mixed fired product of iron oxide and nickel oxide may be mixed. The powder may be impregnated with a basic compound, and the powder may be mixed with iron oxide, nickel oxide and the basic compound, and then compression-molded into pellets.

The catalyst is calcined in the air or in an inert gas in a preparation stage after the mixing of iron oxide and nickel oxide to obtain one or more of iron oxide, nickel oxide, and a composite oxide of iron and nickel. It is preferable to crystallize more than seeds. The firing temperature is preferably in the range of about 600-1000C. If the firing temperature is lower than about 600 ° C, CO due to complete combustion,
The generation of CO ₂ becomes remarkable, and the carbonaceous substance is deposited on the surface of the catalyst. On the other hand, if the firing temperature is higher than about 1000 ° C., a sufficient toluene conversion cannot be obtained.

This catalyst can be added with various compounds in the same manner as the above-mentioned catalyst containing vanadium acid, and can also be used by being supported on a catalyst carrier such as titanium oxide and silica.

In the method for producing phenol of the present invention, oxygen is supplied together with toluene as a raw material, and the supplied oxygen is preferably in a range of about 0.2 to 50 moles per mole of toluene as a raw material. When the supply amount of oxygen is more than about 50 times mol, complete oxidation of the raw material toluene is likely to occur. On the other hand, if the supply amount of oxygen is less than about 0.2 times mol, a sufficient toluene conversion cannot be obtained.

The oxygen to be supplied may be molecular oxygen, but generally, air is used, which may be diluted with an inert gas.

The reaction is generally carried out in the presence of steam. The amount of steam to be supplied is preferably about 1 to 100 moles per mole of toluene as a raw material. If the supply of water vapor is more than about 100 moles, it is not economical, and if it is less than about 1 mole, the phenol selectivity generally decreases.

The space velocity preferably ranges from about 100 to 10,000 h ^-1 . When the space velocity is less than about 100, sufficient space-time yield cannot be obtained, and when the space velocity is more than about 10,000, the conversion of toluene becomes low.

The reaction temperature is preferably in the range of about 250-600 ° C., particularly preferably in the range of about 300-500 ° C. Reaction temperature 60
If the temperature is higher than 0 ° C, the selectivity of phenol decreases, and if the reaction temperature is lower than 250 ° C, the conversion of toluene decreases.

The reaction pressure is not particularly limited as long as the feedstock is kept in a gaseous state under the reaction conditions, but is usually at normal pressure or slightly pressurized.

[0027]

In the method and apparatus for producing phenol of the present invention, first, a reaction gas containing toluene contacts a catalyst containing vanadium oxide disposed on the upstream side of the reactor to form benzoic acid and benzaldehyde. Contact with a catalyst containing iron oxide, nickel oxide and a basic compound arranged on the side to form phenol, but toluene does not change at all even if unreacted toluene contacts the catalyst arranged on the downstream side To produce phenol with high selectivity and high yield as a whole.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a phenol production apparatus according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram of a reactor used in an apparatus for producing phenol. In FIG. 1, reference numeral 1 denotes a quartz reactor. An upstream catalyst chamber 2 is provided on the upstream side (upper side in the figure) of the reactor 1 and on the downstream side (lower side in the figure). A downstream catalyst chamber 3 is provided. The upstream catalyst chamber 2 is filled with a catalyst containing vanadium oxide, and the downstream catalyst chamber 3 is filled with a catalyst containing iron oxide, nickel oxide and a basic compound.

Then, a reaction gas 4 containing toluene is fed from the upstream side of the reactor 1 and sequentially passed through the upstream catalyst chamber 2 and the downstream catalyst chamber 3 to produce phenol.
The produced phenol is discharged from the downstream side.

I. Preparation of Catalyst Examples 1 to 3 Vanadium oxide-potassium sulfate-titania catalysts were prepared as follows. In an aqueous solution obtained by dissolving 3.39 g of ammonium metavanadate (NH ₄ VO ₃ ) in about 50 ml of ion-exchanged water,
While passing SO ₂ gas, 5 ml of a 50% aqueous sulfuric acid solution was added little by little to obtain a blue transparent aqueous solution. Then, 0.5 g of potassium sulfate (K ₂ SO ₄ ) was added to this aqueous solution and dissolved by heating. In addition, this aqueous solution was added to titania (Kanto Chemical
49.5 g (manufactured by Incorporated Co., Ltd.) was charged, evaporated to dryness, dried at 120 ° C. for 24 hours, and calcined in air at 400 ° C. for 5 hours to obtain a target catalyst.

The composition of the obtained catalyst was V ₂ O ₅ : K ₂ S
O ₄ : TiO ₂ = 5.0: 1.0: 94.0 (weight ratio).

The iron oxide-nickel oxide-sodium oxide catalyst was prepared as follows. Iron nitrate _{(Fe (NO 3) 3 ·} 9H 2
O) 200 g and nickel nitrate (Ni (NO ₃ ) ₂ .6H ₂ O) 144
g in 500 ml of ion-exchanged water and a solution of about 100 g of sodium hydroxide in 500 ml of ion-exchanged water were added dropwise to 2 l of room temperature ion-exchanged water while maintaining the pH at 7 to 8. After completion of the dropwise addition, stirring was continued for about 1 hour, and the formed precipitate was filtered and washed.

Next, 100 ml of an aqueous solution containing 1.77 g of sodium carbonate (Na ₂ CO ₃ .10H ₂ O) was added to the gel substance, and the mixture was stirred for about 1 hour. And put the gel-like substance in the air
It was dried at 120 ° C. for 24 hours and further calcined in air at 800 ° C. for 4 hours to obtain a target catalyst.

The composition of the obtained catalyst was Fe ₂ O ₃ : NiO:
Na ₂ O = 51.4: 48.1: 0.5 (weight ratio).

II. Reaction Method A predetermined mesh is placed on the upper part of the quartz reaction tube shown in FIG.
V above_TwoO_Five-K _TwoSO_Four-TiO_TwoCatalyst and lower
The above Fe_TwoO_Three-NiO-Na_TwoO catalyst at the bottom
A fixed amount was filled. And from the top of this reaction tube
Reaction gas consisting of gas, steam, air and nitrogen
It was supplied and reacted at a predetermined temperature.

III. Reaction Conditions and Experimental Results Reaction conditions and experimental results are shown in Table 1.

[0037]

[Table 1]

[0038]

According to the present invention, the use of a reactor in which a catalyst containing vanadium oxide is arranged on the upstream side and a catalyst containing iron oxide, nickel oxide and a basic compound is arranged on the downstream side enables the toluene to be removed. It has the effect of producing phenol with high selectivity and high yield. In addition, since the reaction is performed in one stage, only one reactor is required, which has the effect of making the entire reaction apparatus compact. Furthermore, phenol can be continuously produced from toluene, and a purification step of the produced phenol is not required.

[Brief description of the drawings]

FIG. 1 is a schematic view of one embodiment of a reactor used in the phenol production apparatus of the present invention.

[Explanation of symbols]

 Reference Signs List 1 reactor 2 upstream catalyst chamber 3 downstream catalyst chamber 4 reaction gas containing toluene

────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification symbol FI // C07B 61/00 300 C07B 61/00 300 (56) References JP-A-4-277029 (JP, A) JP-A-4 -330946 (JP, A) JP-A-4-215844 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C07C 37/50 B01J 23/22 B01J 23/78 B01J 27/055 C07C 39/04 C07B 61/00 300

Claims (3)

(57) [Claims] When producing toluene by gas phase catalytic oxidation of toluene, a reaction gas containing toluene is first contacted with a catalyst containing vanadium oxide, and then a catalyst containing iron oxide, nickel oxide and a basic compound. For producing phenol characterized by contacting with phenol 2. The method for producing phenol according to claim 1, wherein the basic compound is an alkali metal or alkaline earth metal compound. 3. A toluene comprising a reactor in which a catalyst containing vanadium oxide is arranged on an upstream side and a catalyst containing iron oxide, nickel oxide and a basic compound is arranged on a downstream side. Equipment for producing phenol by gas phase catalytic oxidation