JPS5970636A - Preparation of 1,4-naphthoquinone - Google Patents

Abstract

PURPOSE:To prepare the titled compound stably for a long period, without increasing the gas-flow resistance of the catalyst bed, by the catalytic vapor- phase oxidation of a raw material composed of an oxygen-containing gas containing a small amount of easily handleable sulfur dioxide and naphthalene using a fixed bed comprising a stationary catalyst layer and a mixed packed layer placed at the upstream side of the stationary layer. CONSTITUTION:1,4-naphthoquinone is prepared by the catalytic vapor-phase oxidation of naphthalene with O2 gas using a stationary catalyst layer composed of vanadium oxide, an alkali metal sulfate, and an alkali metal pyrosulfate. In the above process, the catalytic vapor-phase oxidation of naphthalene is carried out by using a fixed bed comprising the stationary catalyst layer and a mixed packed layer composed of a mixture of a catalyst similar to the above catalyst and an inert granular material and supplying an oxygen-containing gas containing >=1ppm of sulfur dioxide and naphthalene to the fixed bed, wherein the mixed packed layer is placed at the upstream side of the oxygen gas-inlet of the stationary catalyst layer. The sulfur dioxide is converted to sulfur trioxide in the mixed filler layer, and the increase of the gas-flow resistance of the stationary catalyst layer can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention utilizes a fixed catalyst layer of a catalyst in which a catalyst component mainly consisting of monomerized vanadium, an alkali metal sulfate, and an alkali metal pyrosulfate is supported on an inert carrier IC. The present invention relates to a method for producing L+4-naf-1-quinone, which is an improved method for converting L+4 into a catalytic gas phase to +1 so as to be industrially advantageous.

■、4 Contact gas phase of naphthalene for the production of naphthoquinone +
As a catalyst, a catalyst in which a catalytic component mainly consisting of pentate barydium, an alkali metal sulfate, and an alkali metal pyrosulfate is supported on an inert carrier is disclosed in Japanese Patent Publication No. 42-5.
No. 533! Special Publication No. 43-15063, Special Publication No. 52-1
No. 0831, Special Publication Showa 5 +3 2 2 5 5 9
'? It is publicly known from various publications such as No. 5. In addition, when carrying out catalytic gas phase integration using the above catalyst, a sulfur compound is allowed to exist in the reaction space. The method of converting naphthalene into acid is described in
Publications No. 3-28911 and Special Publication No. 55-3049,
Or US Patent Nos. 897,464 and 4. 0
35, 399, etc., and in these known methods, naphthalene usually contains an organic sulfur compound such as thionaphthene with a weight ratio of 01 to 09 as sulfur. Moreover, the sulfur-containing naphthalene is adjusted to an appropriate sulfur content before use.

The present inventors performed a catalytic air oxidation reaction of sulfur-containing naphthalene by filling a tubular reactor with the same number of catalysts as the above catalyst. increased as the reaction temperature increased, and in particular, when the fixed catalyst bed, whose temperature had dropped when the reaction was once interrupted, was repeatedly heated with heated air to the reaction temperature, a significant increase in ventilation resistance was observed. When carried out on an industrial basis using a multi-tubular reactor, this increase in ventilation resistance in each reaction tube significantly impedes the progress of the catalytic gas phase oxidation reaction of naphthalene, and it is often unnecessary to use it. It is something that can be done.

The present inventors7 (1) As a result of various studies to discover the cause of the increase in the airflow resistance of the above-mentioned fixed catalyst layer, we found that the addition of airflow resistance does not occur in the entire fixed catalyst layer. , below the artificial top of the fixed catalyst bed; mainly from the top up to about 1 (catalyst over 1 Jmm, 1 part catalyst 1)′L
The catalyst particles touch each other, and what causes the catalyst particles to adhere to each other is the catalyst component protruding from the catalyst particles, which narrows the flow path of the gas passing through the fixed catalyst layer. It was discovered that this is the cause of increased ventilation resistance.

Moreover, the components protruding from the catalyst grains that fuse these catalyst grains are 2 8041 5V2 0a・3 + 80
It was confirmed that these were a component similar to 4V205.K2O and a component similar to 4V205.K2O, and both corresponded to a composition in which 803 min was reduced from the catalyst component. Therefore, we assumed that the cause of this was the scattering of sulfur trioxide into the gas from the catalyst particles, and confirmed this in a laboratory. That is,
Catalyst particles were packed in a glass tube (22 mm diameter), and air not containing trioxide was introduced into the fixed catalyst layer at a linear velocity of 20 on/'se at 415°C, the same conditions as the naphthalene i-film formation reaction conditions.
c for about 100 hours. At this time, crystals were observed to grow and protrude from the tip of catalyst 1 < 1 at the upper end of the inlet of the fixed catalyst layer, and the analysis value of this growing and protruding crystal was determined by the fusion of the catalyst grains described above. The composition of the prominent components was consistent. Moreover, normal catalyst grains and these crystals grow l~
By supplying air containing tri-decomposed sulfur to the protruding catalyst grains, it was possible to not only prevent the growth of crystals, but also to eliminate the grown crystals.
They discovered that air containing organic sulfur compounds such as thiophene and thionaphthene cannot inhibit the growth of crystals or eliminate them. As a result, the inventors of the present invention have obtained the following
It is called first-to-file. ) proposed a method in which sulfur trioxide is always added to the oxygen-containing gas supplied to the fixed catalyst bed.

However, the present inventors further discovered that instead of always adding sulfur trioxide to the oxygen-containing gas and supplying it to the fixed catalyst layer, a single element-containing gas containing naphthalene was supplied to the fixed catalyst layer to produce naphthalene. In order to carry out the catalytic oxidation reaction, we investigated to provide a method that can effectively utilize sulfur dioxide, which is easy to handle, in place of sulfur trioxide, which cannot be handled. As a result, fixed 1'''9! A fixed bed is used in which a mixed packed bed containing a mixture of fL, catalyst and inert particulates similar to the catalyst of the fixed catalyst bed is provided in front of the medium layer, and l PPm is added to the fixed bed. To carry out the catalytic vapor phase oxidation of naphthalene by supplying the above oxygen-owned scum containing sulfur dioxide and raw naphthalene, first, the sulfur dioxide of IPPm or more is easily catalytically vaporized in the mixed packed bed. 1 PPm or more of sulfur trioxide is present in the oxygen-containing gas which produces sulfur trioxide and which alone passes through the mixed packed bed in the fixed bed and reaches the inlet of the fixed catalyst bed next to the mixed packed bed. Therefore, sulfur dioxide, which is easy to handle, is added to the oxygen-containing gas supplied during the catalytic gas phase oxidation of raw material naphthalene in place of the difficult-to-handle sulfur trioxide in the method of the earlier application. It was discovered for the first time that the method of the present invention has the same effect as that of the prior application and completely eliminates the increase in ventilation resistance of the fixed catalyst layer, and the present invention was achieved based on this discovery. That is, the gist of the present invention is to convert naphthalene into oxygen-containing gas by using a fixed catalyst layer consisting of a catalyst supported on an inert carrier with a catalyst component mainly consisting of vanadium oxide, alkali metal sulfate, and alkali metal pyrosulfate. After catalytic gas phase oxidation,
In producing 4-naphthoquinone, a fixed bed reactor is used, which is provided with a mixed packed bed in which the catalyst and inert particulates are mixed in front of the boron-containing scum inlet of the fixed catalyst bed.
A heated gas containing 1 PPm or more of sulfur trioxide in an acid-containing gas not containing naphthalene is supplied to the fixed bed at 0°C or higher to raise the temperature and/or roast the catalyst in the fixed bed. l+4-naphthoquinone characterized in that the naphthalene is saponified in a catalytic vapor phase by supplying raw material sludge in which 1 PPm or more of sulfur dioxide/yellow and raw material naphthalene are present in an acid-containing gas to the fixed bed. It consists in the manufacturing method.

The catalyst components of the catalyst used in the fixed catalyst layer in the present invention are mainly composed of vanadium oxide, alkali metal cough salt, and alkali gold maple pyrophosphate. And the above alkali metal salt and alkali metal pyro(m M
Examples of the alkali metal in the salt include lithium, sodium, potassium, rubidium, and cephram, but potassium is usually used. In addition to these main components, it is also possible to use vanadium hydrides together with other metal oxides. In such cases, examples of metal oxides that may be used in combination with vanadium oxide include, for example, aluminum. , tan'dusten, molybdenum, tin, antimono, titanium, zirconium, chromium, manganese, cobalt, nickel, lead, salivary lead, niobium, lithium; /tal, cerium, thallium, bismuth, boron, etc. ,
The amount of these metal oxides to be added must not be more than twice the molar amount of vanadium oxide.

The composition ratio of the above-mentioned catalyst components in the catalyst used in the present invention is usually 0.1 to 1, calculated as (a) vanadium/ram, for example, to 1 part by weight of a support mainly consisting of silicon oxide. vanadium oxide, (b
) an alkali metal sulfate in the range from 0.1 to 2.0 parts by weight, calculated as the potassium salt; and (c) an alkali metal pyrochloride in the range from 0.3 to 5.0 parts by weight, calculated as the potassium salt. It consists of sulfate.

Examples of the inert carrier on which the above-mentioned catalyst component is supported include those mainly composed of silicon oxide, titanium oxide, or aluminone oxide, but preferably a carrier mainly composed of silicon meride is used. Mainly acclimatization knowledge J
The carrier may be either a natural product or a synthetic material, and its preparation method includes, for example, treating silica aluminum with a mineral acid or organic acid to reduce the aluminum content to 5% or less and converting it from silicon to 1% silicon. Method for obtaining a carrier
:s 225L) Publication No. 9).

The catalyst used in the fixed insect soot layer in the present invention is prepared by using the raw materials for the above components and the inert body prepared by the above method. , molding,
Known methods for preparing shaped catalysts such as extrusion molding or tablet molding can be applied.

Various shapes can be adopted as the shape of such a catalyst, but generally a cylindrical shape or a cylindrical shape is adopted, and it is usually 3 to 10 mm in diameter x 3
It has a size of ~l Q l1lli 11. The three main components (a) and (b) of the above catalyst components used
.

Among (C), as raw materials for (a) vanadium oxide,
It is not particularly limited as long as it is a vanadium compound that becomes vanadium pentoxide when fired. For example, vanadium pentoxide, ammonium metahana/phosphate, vanadyl sulfate,
/Vanadyl oxalate, etc. Another main point is that (C) as a raw material for alkali metal pyrosulfate, any compound that can be calcined to become alkali metal pyrosulfate can be used, such as alkali metal bisulfate, alkali metal pyrosulfate, etc. Examples include sulfates and sulfuric acid or ammonium sulfate. That is, among the three main components of the catalyst component, (b) alkali metal monosulfate can be used together with sulfuric acid or ammonium sulfate, and a portion of it can also be used as a raw material for the main component (C) above at the same time. It is possible.

Usually fixed catalyst 1* of the catalyst prepared as above
The apparatus for producing 1+4-naphthoquinone by catalytic gas phase oxidation of naphthalene is a fixed bed reactor, generally equipped with a large number of reaction tubes with an inner diameter of 19 to 40 mm, and a molten metal on the outer periphery of the reaction tube. A so-called multi-tubular fixed bed reactor filled with a heat transfer medium of salt is used. Each reaction tube of the reactor is filled with a catalyst described in 2. Usually, the length is l, 500 ~
:3. A fixed catalyst layer of QQQmm is used.

However, in the present invention, a fixed bed reactor is provided with a mixed packed bed in which the same catalyst as the fixed catalyst bed and inert particulates are mixed before the oxygen-containing gas inlet of the fixed catalyst bed. Use. In such a reactor, the oxygen-containing gas is usually supplied from the upper end of the soot layer to the lower part of the upright fixed bed. The inert particulates to be mixed with the above catalyst to form a filling bed include carborundum, alundum, and their constituents, with a total of 3 to 1 (Jmmφ). Non-porous granules having a particle size are selected because the non-porous granules allow the migration of the II carrier component from the catalyst in the mixed packed bed to The ratio of the catalyst in the mixed packed bed is preferably io~30. This is because the ratio of the catalyst in the mixed packed bed is small. If it is too large, it will not be effective in producing the necessary sulfur trioxide by oxidizing the sulfur added, and if it is too large, there is a risk that the catalyst grains in the mixed packed bed will fuse together. The length of the layer is 5 times the length of the fixed catalyst layer.
It is preferable to set the temperature to 2°.

In order to perform catalytic gas phase oxidation of naphthalene using the fixed bed reactor described above according to the method of the present invention, the fixed catalyst bed must first be raised to a predetermined reaction temperature, and if necessary, a single bed (mixed bed) The catalyst (packed bed and fixed catalyst bed) is heated with hot gas, for example, the catalyst is roasted (calcined). In this case, heating and/or roasting of the fixed bed catalyst requires 11
(Usually, if the temperature of the fixed bed catalyst reaches 330°C or higher due to the use of a heated single element-containing gas that does not contain compounds and naphthalene, such as heated air or combustion gas, The oxygen-containing gas supplied to the fixed bed contains lP
It is necessary to have sulfur trioxide of Pm or more present. Generally speaking, it is preferable to add a predetermined amount of sulfur trioxide to the oxygen-containing gas, but in some cases, platinum is added to the acid group-containing gas after adding a sulfur compound such as sulfur dioxide. It is also possible to adopt a method of supplying sulfur trioxide through catalytic gas phase oxidation using a known catalyst such as vanadium oxide.

Next, in the catalytic gas phase oxidation reaction of naphthalene, which is carried out after raising the temperature and/or roasting of the catalyst in the fixed bed, the outer peripheral temperature of the reaction tube is raised to 800 to 450°C; the reaction temperature is: 350 to 1
50℃, and the concentration of sulfur compound-containing raw material is 2.
The space velocity of the raw material gas (S
, V, ) is 1. , 000 to 5,0 OOHr'. The naphthalene mentioned above usually contains organic sulfur-softened compounds such as thionaphthene, or sulfur, which contains Il, 0.5 to 0.5% by weight (assuming the Naphthalene concentration is 40 t/Nm air, the gas contains sulfur trioxide). As [・1～1・l(
lPPm), so the above raw material gas is
When passing through the mixed packed bed of the fixed bed, a part of the sulfur compound contained therein is thrown into the 31-stacked sulfur, and substantially more than 1PP+n'20 trioxide is added to the raw material gas. The population IC of the fixed catalyst bed is reached in the presence of sulfur.

In other words, if a fixed bed with a mixed packing provided in front of the fixed catalyst bed is used, the catalytic oxidation reaction of naphthalene, which is a sulfur compound, can be carried out without adding any oxidation value to the raw material waste. However, it can be said that the sulfur trioxide, which is produced by oxidation of the sulfur compounds contained in naphthalene in the mixed packed bed, can be used for a long period of time without increasing ventilation resistance. However, even in such cases, crystal growth may be observed due to a decrease in sulfur trioxide in the catalyst in the mixed packed bed, compared to some sulfur compounds that are easily oxidized to produce sulfur trioxide. This is because there are some things that are difficult to generate. Therefore, apart from the sulfur compounds contained in the raw material naphthalene, IPPm is present in the raw material gas.
As mentioned above, preferably 1 to 30 PPm, more preferably 1 to 1 OPPm of sulfur dioxide is present,
This is particularly effective for achieving stable operation for a longer period of time without increasing the ventilation resistance of the mixed packed bed and the identified catalyst bed. In other words, sulfur dioxide is gaseous and has relatively low reactivity, so it does not react directly with naphthalene and is easy to handle. Moreover, it is easily oxidized in the mixed packed bed to form trioxide and trioxide.
It is particularly suitable because it has the advantage of producing sulfur. On the other hand, tribaric value yellow binds moisture in the gas phase to form vAt M and may react directly with naphthalene, resulting in, for example, sulfonation, and is therefore not particularly suitable for post-addition. In the present invention, sulfur trichloride, which should remain in the raw material gas used for the catalytic gas phase oxidation reaction of naphthalene at least at the inlet of the fixed catalyst bed, is produced by the oxidation of sulfur dioxide in the mixed packed bed. Sulfur trioxide with an IPPm or more may be used, but preferably, the total sulfur compounds contained in the gas, that is, the sum of sulfur dioxide and thionaphthene, etc., which is 1=1 in the raw material naphthalene, are added to the gas. On the other hand, it is adjusted to 300 PPm or less as 3 acids, 1 h, 1 flow yellow. This is because as the total amount of all sulfur compounds increases, the content of sulfur in the exhaust gas increases, condensing in the equipment after the reactor and causing problems such as corrosion. This is because if the catalyst contains 1,4-naphthoquinone selectivity, the 1,4-naphthoquinone selectivity of the catalyst decreases. In addition, adding sulfur trioxide to a naphthalene-free oxygen-containing gas that is supplied after heating (temperature raising and/or roasting) the catalyst to a fixed bed at 330°C or higher is not recommended. The purpose is to suppress the scattering of sulfur trioxide during heat treatment from the catalyst particles of the fixed catalyst layer, especially the catalyst particles at the upper end of the inlet of the fixed catalyst layer, and to prevent abnormal crystal growth. ,
The amount of sulfur added is preferably kept as small as possible within the range necessary to achieve this effect.

1 meC is preferably 1 to 30 PPm of trioxide sulfur present in the above oxygen-containing scum, but the amount is determined because sulfur trioxide is more likely to scatter from catalyst particles at higher temperatures. , preferably increases gradually as the temperature increases. For example, the abundance rate of sulfur trichloride is L PPm at 380-380°C, 3-20 at 380-430°C.
PPm is preferably 5 to 30 PPm at 430 to 450°C, and is preferably increased steadily as the temperature increases.

As described in detail above, in the method of the present invention, a fixed catalyst layer consisting of a supported catalyst of vanadium varide-alkali sulfate-alkali pyrosulfate system is mixed with an inert particulate material before the oxygen-containing gas inlet part of the fixed catalyst bed. When producing 1,4-naphthoquinone by catalytic gas phase acid ratio of naphthalene using a fixed bed reactor equipped with a mixed packed bed, 1 PPm or more of sulfur diacid and naphthalene are present in the oxygen-containing gas. By supplying the raw material gas to the fixed bed reactor, it is possible to easily and almost completely prevent the addition of ventilation resistance of the fixed catalyst bed, which was a drawback in the conventional method, and to enable stable operation over a long period of time. It has a remarkable effect of achieving an industrial value of '1III1'.

EXAMPLES Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples.

Incidentally, the preparation of the catalyst will be explained in more detail using one example. However, unless otherwise specified, "person in charge" is "person in charge of heavy duty".

Experimental example 1. (Catalyst preparation example) 4.4 kg of silicon oxide, 1 ammonium metavanacnate
．． 9 was thoroughly mixed with 7 kq and mW potassium λ8, 72N sulfuric acid 41 was added thereto, and the mixture was kneaded for 15 minutes using a kneader. The obtained kneaded material was crushed and dried, and coarse particles of 20 mm or more were removed to obtain granules for tabletting. The granules have a cylindrical shape with an outer diameter of 5+++#+, a height of 4 mm, and a grain weight of 1
Seven catalysts were prepared by compressing into tablets of ia'128.

Example[.

The catalyst prepared according to Experimental Example 1 had a unit reaction type of 25
A multi-tubular reactor of + nmφ The combined mixture was reduced to 0. A mixed packed bed was provided by filling each IE to form each fixed bed. Each fixed bed of this multi-tubular fixed bed reactor was heated at an average heating rate of 4°C/Hr by supplying heated air of 1000Hr at an average heating rate of 4°C/Hr from the upper end inlet of each unit reaction tube.
It took some time to raise the temperature to 420℃. During this heating time,
3 PPm of sulfur trioxide at 330-380℃,'
It was added at a rate of 1 OPPm at 380 to 410°C and 15 PP'm at temperatures above 410°C. Next, the reaction temperature was 420°C from the upper end inlet of each unit reaction tube to the reactor.
Air containing 3 PPm of sulfur divanide and 4097 Nhn' of naphthalene (containing 1.4% thionaphthene) was supplied at S, V, 1,400 Hr' for continuous catalytic gas phase oxidation of naphthalene. I drove it for a year. During this period, the naphthalene conversion rate was about 98%, the naphthoquinone yield was about 40%, and the phthalic anhydride yield was about 70%.

During that time, when the reaction was stopped for equipment inspection etc. 10 times, the temperature of each fixed bed in the reactor was 300-2380°C.
S, V, in which sulfur trioxide was added to the fixed bed in the same proportion as above.

The temperature was raised to 420° C. by supplying heated air for 1000 hours.

The ventilation resistance during operation in each fixed bed of the reactor was 102 to 10 (1mHf') at the start of operation, but it was still 102 to 10611LIIIHg after one year of operation, and even after one year of operation, the ventilation resistance increased. In each fixed bed, no <1 binding was observed in the catalyst in the mixed packed bed, and there was no increase in ventilation resistance at the upper end of the fixed catalyst bed.

Comparative Example 1゜The catalyst prepared according to Example 1 was placed in a multi-tubular reactor having a unit reaction tube of 25mm x 3000+11111h.
171 catalysts are packed per unit reaction tube to form a fixed catalyst layer, and a preheating layer with an average particle size of 5
The carborundum of cabinet φ is 0. Each IE was filled. Each fixed bed of this multi-tubular fixed bed reactor is S, V', 1. ．． 0
Average heating rate 4°C using heated air of 00Hr'
/Hr, the temperature was raised to 420°C in about 100 hours, and then each fixed bed was heated to a reaction temperature of 420°CXS, V, 1,40
Naphthalene (contains 1.4 units of thionaphthene) at 0Hr'
Naphthalene was continuously oxidized in a catalytic gas phase by supplying heated air containing 40 q/IJrrr, and the reactor was operated for 8 months.

During that time, when the reaction was stopped 8 times to inspect the equipment, etc., the temperature of each fixed bed in the reactor dropped to 300 to 380°C, so each time, S, V, 1,000
The temperature was raised to 420° C. by supplying heated air of 100 hr.

The ventilation resistance during operation of each fixed bed in the reactor was 102~l fJ OM Hf at the start of operation, but after 8 months of operation it increased significantly to 2::IO-2l0-25
0, making further driving difficult.

The ventilation resistance value measured for the 30 test L-th reaction tubes in the above reactor using the same measurement method as in Example 2 below was 8t''89hg (average 85gHg) at the start of operation.
f), after 8 months of operation L L 7~: 428 mmH
! 7 (average 2 OflmnlHf, ).

Example 2 A: The method of the present invention was carried out using a multi-tubular fixed bed reactor in which the mixing volume ratio of moon lji and carborundum in the mixed packed bed was 15:85 (catalyst ratio 15 volume tA'). 28 test tubes of 1 degree reaction tube of Example 1 were prepared.

B: Mixing volume of catalyst and carborundum in mixed packed bed (
Twenty-eight test tubes were prepared by carrying out the method of the present invention in the same manner as in Example 1, except that the pre-stop was set to 30 Nia0 (catalyst ratio: (0 volume)).

C: a, only carborundum is used as the combined packed layer (touch ratio 0
30 test tubes of unit reaction tubes were carried out in the same manner as in Example 1 except that a single packed bed was used.

In each case of A + B + 0 above, air was flowed at 15°C and 2r11'/Hr into each test tube of each unit reaction tube at the start of operation and after - years of operation, and the ventilation resistance at that time was measured. were as shown in Table 1 below.

In the case of B, there is a very small amount of catalyst in the mixed packed bed of the unit reaction tube. Fi adhesion was observed, but no fusion was observed in the catalyst particles at the upper end of the fixed catalyst layer of the unit reaction tube. This is because the ratio of the catalyst in the mixed packed bed is the largest within the preferred range of 10 to 30 volumetric ratios.

As shown in the results in Table-[, the fixed bed catalyst temperature rise and/or
Alternatively, an oxygen-containing gas containing 1,000,000 yen was used for Yai 1 yaki, and 1. P
Pm or higher, 1 lrf yellow and raw material naphthalene/S
Even in the case of the method using a gas containing MUSUJ, in the case of Example A+B using a fixed bed reactor consisting of a mixed packed bed of a friend medium and carborundum and a fixed catalyst bed, in the case of A + B of the example using a fixed bed reactor consisting of a mixed packed bed of a friend medium and carborundum and a fixed catalyst bed, it is possible to use a gas containing no catalyst. - Compared to the case of Comparative Example C, which uses a fixed bed reactor consisting of a packed bed and a fixed catalyst bed, the increase in ventilation resistance is much smaller, and even when looking at all the layers of the fixed bed, it is almost M
) is not observed or is not observed at all. From the AIBQ Himaki of the example, when the ratio of catalyst in the mixed packed bed is 】O ~; A, which is close to a particularly preferable value even within the preferable range of 30 volume suspension, the increase in ventilation resistance is , it was not observed at all in either the mixed packed bed or the fixed catalyst bed, whereas the catalyst ratio in the mixed packed bed was 10 to 3.
It can be seen that in the case of B, which is the largest within the preferred range of 0%, a very slight increase in ventilation resistance is observed only in the mixed packed bed, and not at all in the fixed catalyst bed.

One person for patent Kawasaki Hisei Industries Co., Ltd. Agent: Patent Attorney Tsunebe Ogawa

Claims (1)

[Claims] 1. In producing 4-naphthoquinone by catalytic gas phase oxidation of naphthalene with an oxygen-containing gas using vanadium oxide, alkali metal Wf, I ￥12 salt and the fixed catalyst layer. Using a fixed bed reactor equipped with a mixed FC packed bed in which the catalyst and inert particulates are mixed in front of the oxygen-containing gas inlet, the fixed bed at 33υ°C or higher is filled with naphthalene-free + gas After heating and/or roasting the catalyst in the fixed bed by supplying a heated gas in which trisulfur oxide of LPPm or more is present in the containing gas, the catalyst in the fixed bed is heated in an oxygen-containing gas. IPPm
A method for producing 1,4-naphthoquinone, which comprises supplying a raw material containing the above sulfur dioxide and naphthalene as a raw material, and oxidizing naphthalene in a catalytic gas phase. 2. A heated gas containing 1 to 30 PPm of sulfur trioxide in a naphthalene-free oxygen-containing gas is supplied to the fixed bed at a temperature of 330° C. or higher to raise the temperature of the catalyst in the fixed bed and/or or roasting the method according to claim 1. :(, In the fixed bed, 1 PPm or more of sulfur dioxide and raw material naphthalene are present in the oxygen-containing gas, and the total sulfur compounds contained in the gas are calculated as 300% sulfur oxide.
3. The method according to claim 1 or 2, wherein naphthalene is catalytically oxidized in vapor phase by supplying a raw material gas having a PPm or less. -1 The method according to claim 3, wherein 1 to 30 PPm of sulfur is present in the oxygen-containing gas. 5. The method according to claim 3, wherein 1 to lUPPm of sulfur trioxide is present in the oxygen-containing gas. (5. In the fixed bed, 0 as sulfur in the oxygen-containing scum,
Claims 1, 2, 3, 4, or 5 for catalytic vapor phase oxidation of naphthalene by supplying raw material scraps in which raw material naphthalene containing a 05-05 weight value compound is present. The method described in Section 5. 7 Claims 1, 2, 8, and 1, in which the ratio of the catalyst in the mixed packed bed is 10 to 30 by volume;
Item 5 or Item 5 (The method described in Item 5. & The length of the mixed packed bed is 5 to 20 times the length of the fixed catalyst bed.
%, the method according to claim 1 or claim 7. 9. The reaction temperature for catalytic gas phase oxidation of naphthalene is 350
9. A method according to claim 1, 7 or 8, wherein the temperature is ~450°C.