JPS61100543A - Production of anthraquinone - Google Patents

Abstract

PURPOSE:To produce anthraquinone, in high yield and efficiency, in an industrial scale, by the catalytic oxidation of anthracene with a molecular O2 at a specific increased ratio using a laminated catalyst having sufficiently high activity and selectivity even under an O2 concentration to avoid the explosion. CONSTITUTION:The objective compound can be produced by the catalytic oxidation of anthracene with molecular O2, by contacting a mixture of anthracene and O2 having high anthracene concentration, an anthracene/O2 ratio of >=60g/NM<3> and an O2 concentration of 5-15vol% with a laminated catalyst consisting of the former catalyst having a height corresponding to 30-70% of the total height of the catalyst and obtained by supporting a catalytic active substance composed mainly of V2O5 and TiO2 as main components and added with an oxide of at least one element selected from Li, Na, K, Rb, Cs and Tl and containing P2O5 and Nb2O5 on an inert carrier, and the latter catalyst having a height corresponding to the remaining part of the total height and having the same composition as the former catalyst provided that the oxide content is lower than the former catalyst. EFFECT:The height of the hot spot in the contacting layer is suppressed remarkably, the thermal deterioration of the catalyst can be mitigated, and the catalyst life can be prolonged.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing anthraquinone by catalytic gas phase oxidation of anthracene with a molecular oxygen-containing gas. In particular, the present invention provides a method for efficiently producing anthraquinone by carrying out a catalytic oxidation reaction at a higher ratio of acidracene/molecular oxygen-containing gas.

[Conventional technology]

Anthraquinone has been produced for a long time by catalytic gas phase oxidation of anthracene, and the yield is also low.
As shown in the example of No. 0-24305, a theoretical yield of 90 molt or more was achieved, and it can be said that the technical level of achievement as a catalyst is extremely high.

However, as is clear from the Examples of the same issue, the catalytic oxidation of anthracene has hitherto been carried out under conditions of a very low anthracene/air ratio and a very high space velocity in terms of catalytic performance.

This is because this low anthracene/air ratio is considered to be an unavoidable measure to keep the gas composition on the inlet side of the reactor out of the flammable range.

Catalytic oxidation at a low anthracene/air ratio concentration has a problem in that it is difficult to maintain the reactor temperature calorically in its industrial implementation. this .

Because of the excellent selectivity of the above-mentioned catalyst, the amount of heat generated by side reactions such as combustion to carbon dioxide and carbon monoxide (Cox) is small, and the heat of formation to anthraquinone is smaller than that of anthracene at about t41kca11 mol. However, the major reasons are that the absolute concentration of the oxidized substance is low and the high space velocity causes a large amount of reaction gas to carry away the heat generated in the reactor to the outside of the reactor. For this reason, in actual industrial practice, anthracene containing many impurities such as carbazole and phenanthrene is used as a raw material in order to ensure the calorific value in the reactor, and the heat of combustion reaction of these impurities causes the reactor to react. A sufficient amount of heat is ensured to maintain a self-sustaining temperature.

Due to such countermeasures, many impurities are mixed into the anthraquinone produced, and the purification process requires many steps.

In order to make the oxidation reactor calorically independent, it is preferable to reduce the amount of conducting air in order to suppress the amount of sensible heat of the gas. However, in order to secure the production amount, it will be necessary to increase the anthracene/air ratio accordingly. However, under such conditions, conventionally known catalysts will cause excessive oxidation reactions. With the catalyst disclosed in the No. 2 issue, anthraquinone was obtained at a yield of 105% by weight at an anthraquinone/air ratio of 33.9/NM', but when the ratio was increased to 8017NM3, the heating point (hot 5pot) of the catalyst layer was extremely high. increased to 84% by weight
It is known that anthraquinone can be obtained only with a moderate yield (see Comparative Example 1 below).

[Problem that the invention seeks to solve]

Therefore, the object of the present invention is, first, to produce anthraquinone in high yield by contacting a gas with a high anthracene concentration in which the ratio of anthracene/air or molecular oxygen-containing gas is 60 I/NMs or more, particularly 80 g/NM3 or more. secondly, it provides a catalyst with sufficiently high activity even when the oxygen concentration employed is as low as 5 to 15 volumes to avoid explosion when the reactor inlet gas composition enters the combustible range; a third aspect of the present invention is to provide a catalyst having a selectivity;
The purpose of this invention is to provide a practical industrial implementation method for achieving the first and second objectives.

[Means for solving the problem] First, as a result of investigating a catalyst composition that has sufficiently high activity even at low oxygen concentrations, we found that a substance whose main components are vanadium pentoxide and titanium dioxide, an alkali metal,
A catalyst in which an active material containing thallium, phosphorus, and niobium as co-catalysts is supported on a porous carrier mainly composed of silicon carbide reduces the oxygen concentration in the raw gas to 15 vol. or less, especially 10 vol. ti or less. It was found that it has very high activity even under the following conditions. In addition, in such a catalyst system, a catalyst with a higher amount of alkali metal or thallium added to the front part of the catalyst layer (on the inlet side of the reaction gas), and a catalyst with a higher amount of alkali metal or thallium added to the rear part than in the front part. By using a stacked catalyst system with a reduced amount of catalyst, high yields can be achieved even at high concentration conditions with much higher anthracene/molecular oxygen-containing gas ratios than are achieved with conventional catalysts. It has been found that anthraquinones can be obtained at a relatively low concentration.

More specifically, the present invention can be specified as follows.

When producing anthraquinone by catalytic phase oxidation of anthracene with a molecular oxygen-containing gas, one vanadium component is added to vanadium pentoxide (V2O,) at a height of 30 to 70% of the total catalyst layer height as a first stage catalyst. as 1-20
parts by weight and titanium component as titanium dioxide (TiOz), 99 to 80 parts by weight, and v20. and Ti0z, at least one element (X) selected from the group consisting of lithium, sodium, potassium, rubidium, cesium, and thallium is added as an oxide (X).
20), 5.0 to 12.0 parts by weight as the phosphorus component, 0.05 to 5.0 parts by weight as phosphorus pentoxide (P2O3), and 0.05 to 5.0 parts as the niobium component as niobium pentoxide (Nbt05).
05 to 5.0 parts by weight of a catalytically active material supported on an inert carrier is arranged as a subsequent catalyst at a height of the remaining 70 to 30% of the total catalyst layer height, The vanadium component is ■1 to 20% by weight based on 20°, the titanium component is 99 to 80 parts by weight as TiO2, and v20. and TiO2, the X component is 0.05 to 3.0 parts by weight as X, 0, the phosphorus component is 0.05 to 5.0 parts by weight as P2O5, and the niobium component is Nb, 0. 1. A method for producing anthraquinone, comprising: supporting an inert carrier with a catalytically active substance containing 0.05 to 50 parts by weight of each anthraquinone.

(2) 5 to 15% oxygen by volume as molecular oxygen-containing gas
, 5 to 10% by volume of moisture, O to 4 volumes of carbon dioxide, θ to 2 volumes of carbon oxide, and the remainder essentially nitrogen.

(3) As an inert carrier, use a porous carrier having an aluminum content of not more than 10% by weight as aluminum oxide (kites), a silicon carbide content of at least 500 parts by weight, and an apparent porosity of at least 10%. The method described in item (11) (2) above, characterized in that:

The present invention will be explained in more detail below.

In the present invention, the crystal form of titanium dioxide, which is a catalyst raw material, is not particularly limited, and may be anatase form or rutile form with a specific surface area of 1 to 50 d/g, particularly 1 to 30 nl/9.
Alternatively, a finely powdered mixture of the two may be used. Other catalyst materials, i.e., alkali metals such as vanadium, lithium, sodium, potassium, rubidium, cesium, thallium, phosphorus, and niobium, may be any starting materials that decompose into oxides when heated. It is appropriately selected from salts, nitrates, sulfates, carbonates, organic acid salts, etc.

Further, among the catalyst components related to the present invention, titanium dioxide has a specific surface area of 1 to 50 cm, 7 g,
In particular, it may be substituted with 1 to 30 z/I of finely powdered zirconium dioxide, tin dioxide or a mixture of both, and a total of 10% of both vanadium pentoxide and titanium dioxide.
Aluminum, silicon, lead, antimony chromium, tungsten, cobalt, iron, nickel and/or manganese can be added in a total amount of up to 3 parts by weight in terms of oxides based on 0 parts by weight.

As the inert carrier, alpha alumina, silica, quartz, silicon carbide, silicates of aluminum and magnesium are used, preferably with an aluminum content of k120. 10% by weight or less, especially 5% by weight or less, and silicon carbide is 50% by weight or more, especially 8
Contains 0% by weight or more and has a porosity of 10% or more, especially 2
A porous carrier of 0 or more is used. The size of the carrier is 3
Preference is given to spheres, rings, saddle shapes with an average diameter of ~10 m1E.

The catalytically active substance is supported on the inert carrier by a conventionally known method, but preferably titanium dioxide is emulsified in an oxalic acid or other organic acid solution in which the catalytically active substance is dissolved to form a slurry. It is carried out by spraying onto a carrier heated to ~2,50°C. The support obtained in this way was heated at a temperature of 400 to 550°C under air circulation to
It is considered as a completed catalyst at 0 hours and dawn hours. As a finished catalyst, the supported amount of catalytically active material is 3 to 150 JF, preferably 8 to 5 JF.
The range is 0 Ji'/10 G cc-carrier.

The oxidation reaction of anthracene is effective for internal diameters of 20 to 40, especially 25 to 3o11! , length 1~5rn1, especially 3~3.5
The total height of the front and rear catalysts in the ffi tube is 2 to 3 m.
This is done by filling it so that it becomes .

is filled. The reaction tube is immersed in a heating medium tank such as molten salt, and a gas containing anthracene mixed with a molecular oxygen-containing gas is preheated to 120 to 150° C. to carry out an oxidation reaction.

Air is generally used as the molecular oxygen-containing gas, but other gases include 5 to 15% by volume of oxygen, 0 to 10% by volume of water vapor,
A mixed gas is used, the balance of which is an inert gas such as CO□CO, argon, and N7.

For such air or molecular oxygen-containing gas INM, the amount of anthracene is 20 to 100 g, especially 60 to 80 g.
9 and introduced into the catalyst layer at a space velocity of 1000 to 8000 Hr', particularly 1000 to 4000 Hr''.The reaction tube is maintained at 350 to 450°C by the molten salt.

In order to carry out the oxidation reaction with a high anthracene/molecular oxygen-containing gas ratio, a part of the waste gas after collecting anthraquinone with a collector or washing group is dehumidified or recycled to the reactor inlet side without dehumidification. Mix with fresh air sucked in to increase the oxygen concentration to 5 to 15% by volume, especially 8
It is safe and economical for industrial processes to use the molecular oxygen-containing gas adjusted to a volume of ~12 cm.

Under such conditions, anthraquinone can be obtained from anthracene in a yield of 100% by weight or more.

A more detailed explanation will be given below with reference to Examples.

Example 1 450 g of oxalic acid was dissolved in 6400 cc of water to obtain an oxalic acid aqueous solution, and 201.2. f,
Cesium sulfate 150.6. ? , potassium sulfate 410B, 5
．． 9. 31.7 g of ammonium dihydrogen phosphate and 19.9.9 g of niobium chloride were added and dissolved.

This has a specific surface area of 2o, (7g of anatase type Ti02i
sooII was added and emulsified using a stirrer to obtain a catalyst slurry liquid. In an externally heated rotary drum with a diameter of 3oc IIK and a length of 50 m, a spherical material with an apparent porosity of 37 cm and an average diameter of 5 mm, consisting of an alumina content of 3% by weight, a silicon carbide content of 92% by weight, and the balance 5i02 was placed. porous carrier 2000c
c and preheated to 200°C. Next, while rotating the drum, the above catalyst slurry liquid was sprayed to form a catalyst active substance of 1
It was supported at a ratio of 01/1 o o cc-carrier. This support was calcined in an electric furnace at a temperature of 540° C. for 6 hours under air circulation to obtain a completed catalyst. This is referred to as the front stage catalyst - person.

A catalyst obtained in the same manner except that the catalyst was changed to 25.1 N of cesium sulfate, 1 B of potassium sulfate, and 1.9 to
carrier). The compositions of the front and rear catalysts were as follows.

V2O3-T t02- Cs2O- to 20-P2O3
-Nb205 front stage catalyst-A 8 92 6
3 1 o, s (weight ratio) latter stage catalyst-B
8 92 1 0.5 1 0.5 (#)
A tube with an inner diameter of 25 mm and a length of 3 m, immersed in a molten salt bath, was first filled with catalyst-B to a bed height of 1.5 m, and then 1 m of catalyst-B was added on top of it.
Catalyst-A was filled to a height of 360° C. and the temperature was maintained at 360°C. To this, a mixed gas INM' consisting of 10% by volume of oxygen, 5% by volume of water vapor, and 85% by volume of nitrogen was added to anthracene (purity 98%).
．． 5 h) When a mixed gas loaded with 85I and preheated to tSO°C was introduced at a space velocity of 2000 Hr-' to carry out a reaction, anthraquinone was obtained with a yield of 108.5% by weight.

Example 2 A rutile crystal with a specific surface area of 57Fl'/Il was used as titanium dioxide, rubidium carbonate and potassium nitrate were used as the alkali metal compounds, and 4% by weight of magnesium oxide (MgO) and 5i027% by weight were used as carriers. , a spherical porous carrier with an apparent porosity of 42 cm and six diameters, made of 89% by weight of silicon carbide, and a supported amount of catalytically active material of 121/100 cc were used.
-The following catalysts C and D were prepared in the same manner as in Example 1 except that they were used as carriers.

V2O5-T i02- Rb2O-B20- P2O
5-Nb,o.

First stage catalyst - 059510221 Second stage catalyst - 05950,50,532 1.25 m of second stage catalyst - D was placed in a tube with an inner diameter of 27 mm and a length of 3 m immersed in a molten salt bath, and 1.25 m of first stage catalyst - C was placed on top of it.
From the upper part of the reaction tube packed in a 2577L stack and maintained at 410°C, a mixed gas of 8% by volume of oxygen, 10% by volume of water vapor, 3% by volume of carbon dioxide, 1 volume of -carbon oxide and 78 volumes of nitrogen was added at 98.5%. % purity of anthracene
After preheating to 150 DEG C. and carrying out the reaction at a space velocity of 2000 Hr', anthraquinone was obtained with a yield of 107.6 wt%.

Example 3 Using the same method as in Example 1, using catalyst constituent raw materials with a specific surface area of 4 i / I and an anatase/rutile ratio of 3
Titanium dioxide with a ratio of 2/68 and a surface area of 3.
s m”/9 tin dioxide, ammonium vanadate, ammonium dihydrogen phosphate, niobium chloride, sodium nitrate, thallium nitrate and apparent porosity 35%, purity 98
The following catalyst was prepared using a 1s SiC self-sintering carrier. The loading ratio for both the front and rear catalysts is K 1511/1.
00 CC-carrier.

v, o, :'l'' to, : 8nO1:Na2O
:'rz,o :p,o, :Nb2O.

Front stage catalyst-B1258 30 1 10 1
1 Post-stage catalyst-F1258 30 1 2
1 1 Into a tube with an inner diameter of 27 and a length of 3 m immersed in a molten salt bath, 1 m of post-catalyst-F was placed, and 1 m of pre-catalyst-E was placed on top of it.
The stack was packed to a height of 577L and maintained at 415°C.

From the upper part of the reaction tube, a synthesis gas consisting of an oxygen concentration of 8% by volume, 5 volumes of water vapor, and 87 volumes of nitrogen was loaded with 98.5% of ant-2-cene at a ratio of 7017 NM', and the gas was preheated to 150' ClC. Later space velocity 2500H
r-" to the catalyst layer and the reaction was carried out, 105
．． Anthraquinone was obtained with a yield of 3% by weight.

Example 4 Titanium dioxide with a specific surface area of 9 d/y, rutile content of 60%, and anatase content of 40% was used, and the alkali metal compounds were lithium carbonate, sodium carbonate, cesium sulfate, and potassium sulfate. In particular, a ring-shaped self-sintered silicon carbide product with an outer diameter of 8 mm, an inner diameter of 4 lines, and a length of 8 nm with a porosity of 35 mm was used as the carrier, and the support rate was 8.51/100 CC-.
The following catalysts G and H were prepared using the same catalyst raw materials as in Example 1 and using the same method except that they were used as carriers.

V20* -T 10H" Na to -B20-
P tOs -Nb, 05 front stage catalyst - GIO90180
,50,lV2O1-Ti02-Li20-Ca20-
P2O5-Nb205 latter stage catalyst-H10900,51
0,50,1 with rear stage catalyst-H at 177! Next, the front and rear catalysts-G were stacked and packed on top of each other to a bed height of 1.5 m, and the temperature was maintained at 385°C.

Air was loaded with anthracene 80I/NM3 from the upper part of the reaction tube and led at a space velocity of 3000 Hr', and the generated gas was sent to a water washing column to collect anthraquinone. The top temperature of the washing tower was maintained at 30°C, and the waste gas discharged from it was heated to 71. s
t4 is recycled to the air blower, and the space velocity is 3.
The amount of air suction was reduced to 000 Hr'. At equilibrium, the composition of the inlet gas is 10% by volume of oxygen, 5% by volume of water vapor, 5.6% by volume of carbon dioxide, 0.4% by volume of carbon monoxide, and 79% by volume of nine elements; ) ratio was kept at soy/NM3. The anthraquinone yield at equilibrium was 110.5% by weight.

Comparative Example 1 The following catalyst was prepared according to Example 1 of Japanese Patent Publication No. 50-24305.

That is, oxalic acid 450I was dissolved in 6400 cc of water to prepare an oxalic acid aqueous solution of ammonium metavanadate 201.6.
9 was added and dissolved under heating.

This includes cesium sulfate 46.2.9, potassium sulfate 33
, O, and p were dissolved in a small amount of water, added to the above vanadium solution, and stirred at 50 to 60°C for 30 minutes.

Add Ti02 (rutile type crystal: anatase type seed crystal = 95:5 weight ratio, surface area 7, tm/I by BBT method) to this solution.
) xsooi was added and thoroughly mixed and emulsified using an emulsifier to prepare a catalyst slurry.

Diameter 30c++t, length 50cIr that can be heated from the outside
Add 2,000 cc of SiC carrier with a diameter of 3 to 5 into a stainless steel rotating body of L, and spray and bake the catalyst slurry while heating to coat the catalyst material on the carrier at a rate of about 91/1 o
It was supported on a cc carrier. It was baked at 500° C. for 8 hours in a Matsufuru furnace with air passing through. The composition of Kono catalyst is
V2O5: TiO2'Ca20' inner diameter 25
1! A 1m long 377L pipe was filled to the height of 2 doors and 42
Maintained 0oCK. This has an anthracene/air ratio of 33.
31 / NM” at a space velocity of 5000
When induced and reacted with Hr-', 110.1% by weight
Anthraquinone was obtained in a yield of .

Next, when the anthracene/air ratio was set to 801/NM'' and the reaction was carried out at a space velocity of 2000 Hr', anthracene was obtained with a yield of only 84.5% by weight. Using the same composition of synthesis gas as in Example 3, the yield was 81.3% by weight.

〔Effect of the invention〕

As shown in Examples 1 to 4, the method of the present invention makes it possible to operate with an anthracene concentration more than twice that of the conventional method, and the yield is almost the same as in the case of a low gas concentration. Since a large amount of anthracene is oxidized by blowing a small amount of air or molecular oxygen-containing gas,
High energy saving benefits can now be obtained. In addition, since a catalyst with high activity is used as an oxidizer for molecular oxygen-containing gas with an oxygen concentration of 15 volumes or less, it increases the anthracene layer content and at the same time reduces the risk of combustion of the mixed gas. To avoid this, it has become possible to adopt a process that recycles waste gas, which is an inert gas.

・Also, such a stacked catalyst can reduce the heat point (h) of the catalyst layer.
Since the height of ot 5pot ) is greatly suppressed, there is an advantage that thermal deterioration of the catalyst is reduced and the life of the catalyst is extended. For example, although the catalyst according to the example of Japanese Patent Publication No. 50-24305 is used under milder conditions than the catalyst of the present invention, if the degree of yield decrease after a certain period of time is 1, the catalyst of the present invention is It will be about 1.5 to 2 of that.

Patent applicant Nippon Shokubai Kagaku Kogyo Co., Ltd. Procedural amendment (voluntary) July 2, 1960 Commissioner of the Japan Patent Office Manabu Shiga 1, Indication of the case 1982 Patent H No. H220591 2, Name of the invention Anthraquinone Manufacturing method 3, person making the correction

Claims (3)

[Claims] (1) When producing anthraquinone by catalytic gas phase oxidation of anthracene with a molecular oxygen-containing gas, the vanadium component is replaced with vanadium pentoxide (V_2O_5) at a height of 30 to 70% of the total catalyst layer height as a first-stage catalyst. As 1~
20 parts by weight and the titanium component were added to titanium dioxide (TiO_
2) as 99 to 80 parts by weight, and further V_2O_5 and Ti
With respect to a total of 100 parts by weight of O_2, at least one element (X) selected from the group consisting of lithium, sodium, potassium, rubidium, cesium, and thallium is added as an oxide (X_2O) of 5.0 to 12 .0 parts by weight,
Phosphorus component is 0.05 as phosphorus pentoxide (P_2O_5)
~5.0 parts by weight and the niobium component were added to niobium pentoxide (Nb
A catalytically active material containing 0.05 to 5.0 parts by weight of each of _2O_5) is supported on an inert carrier, and the remaining 70 to 30% of the total catalyst layer height is used as a subsequent catalyst. Add the vanadium component to the height of V_2O_
5 as 1 to 20% by weight and titanium component as TiO_2
99 to 80 parts by weight as well as V_2O_5 and TiO_
2, the X component is 0.05 to 3.0 parts by weight as X_2O, the phosphorus component is 0.05 to 5.0 parts by weight as P_2O_5, and the niobium component is Nb_
1. A method for producing anthraquinone, which comprises disposing a catalytically active material containing 0.05 to 5.0 parts by weight of 2O_5 on an inert carrier. (2) 5 to 15% oxygen by volume as molecular oxygen-containing gas
Claim (1) is characterized in that a gas having a composition of 5 to 10% by volume of water, 0 to 4% by volume of carbon dioxide, and 0 to 2% by volume of carbon monoxide with the remainder substantially nitrogen is used. the method of. (3) As an inert carrier, use a porous carrier having an aluminum content of 10% by weight or less as aluminum oxide (Al_2O_3), a silicon carbide content of at least 50% by weight, and an apparent porosity of at least 10%. The method according to claim (1) or (2), characterized in that: