JPS63255274A - Production of phthalic anhydride - Google Patents

Abstract

PURPOSE:To obtain phthalic anhydride advantageously, by bringing a molecular oxygen-containing gas mixture having indene, etc., into contact with a catalytic layer prepared by supporting each specific amount of titanium dioxide, vanadium pentoxide and an alkali metallic compound in a nonporous inert carrier. CONSTITUTION:A molecular oxygen-containing gas mixture having indene and/or indane and preferably further naphthalene and/or o-xylene is brought into contact with a catalytic layer packed with a catalyst prepared by supporting a catalytic active component consisting of 70-90wt.% titanium dioxide, 10-30wt.% vanadium pentoxide and 0.5-5wt.% (calculated as sulfate) alkali metallic compound on a nonporous inert carrier and oxidized to give phthalic anhydride in high yield and high productivity by using indene and/or indane relatively richly contained in coal tar or petroleum fraction as part or the whole of the raw material.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a method for producing phthalic anhydride.

Specifically, the present invention relates to a method for producing phthalic anhydride by catalytically oxidizing indene or indane in a gas phase using a molecular oxygen-containing gas.

(Prior art) Phthalic anhydride is industrially produced by catalytic oxidation by passing a mixed gas of naphthalene or ortho-xylene and molecular oxygen-containing gas through a multitubular reactor filled with a catalyst at high temperature. Manufactured.

However, raw materials such as naphthalene and ortho-xylene are expensive, and their use is limited to hanging hooks. Therefore, instead of using raw materials such as naphthalene or orthoxylene, indene or indane, which is relatively contained in coal tar and petroleum distillates, is used as a raw material or a part of the raw material, and it is oxidized in the gas phase. It would be advantageous if phthalic anhydride could be produced using the same method.

Chemical Abstracts CA32 (15) 9785 describes a method for producing phthalic anhydride by catalytic gas phase oxidation of a fraction containing indene, indane, etc. or indane and xylene, etc.
J or US Pat. No. 2,581, '068g, these methods do not allow phthalic anhydride to be obtained with an industrially satisfactory yield or productivity.

(Problems to be Solved by the Invention) The object of the present invention is to produce phthalic anhydride with good productivity and high yield using indene or indane as part or all of the raw materials.

(One step f to solve the problem) The above purpose is to combine 70-90% by weight of titanium dioxide, 10-30% by weight of vanadium pentoxide, and 0% by weight of an alkali metal compound.
．． Molecular oxygen containing indene and/or indane in a catalyst bed filled with a catalyst formed by supporting a catalytically active component of 5 to 5 M suspension % (calculated as sulfate) on a non-porous inert carrier. This is achieved by contacting and oxidizing the gas mixture.

The catalyst used in the present invention contains 70 to 90% by weight, preferably 75 to 85% by weight of 6-titanium diacid, on a non-porous inert carrier.
% heavy weight, 1% vanadium pentate, 10-30% weight loss, preferably 12-22% by weight, and 0.5% alkali metal compound.
20 to 200, preferably 40 to 15 Q3 catalyst components are supported per 1 ρ of the carrier, preferably 2 to 4.5 weight percent, preferably 2 to 4.5 weight percent (calculated as sulfate). be. Note that the catalytically active component contains MO
, W 2 , Fe, Co 2 , Sn, and other compounds may be contained in small amounts.

This catalyst is produced, for example, by a conventional method. That is,
Vanadium pentoxide or a vanadium compound that can be converted to vanadium pentoxide by heating, such as ammonium vanadate, or vanadium sulfate, oxalate, formate, acetate, tartrate, etc., is mixed with water or an organic solvent such as alcohol and water. Add a suitable alkali metal compound thereto, mix with finely divided titanium dioxide or titanium hydroxide, and spray the resulting slurry mixture onto an inert carrier, or spray the slurry mixture onto an inert carrier. It is produced by immersing an inert carrier therein and then heating it to a predetermined temperature, or by spraying the slurry mixture onto the carrier heated to a predetermined temperature.

Suitable alkali metal compounds include, for example, potassium, rubidium and cesium compounds, preferably cesium compounds. Alkali metals can be used in the form of sulfates, oxides, carbonates, acetates, nitrates, etc., but sulfates are preferred. With the exception of sulfates, these compounds convert to oxides at relatively high temperatures. In the catalyst, the alkali metal is sulfur! ! L salt,
It exists as oxides, vanadates, etc., but most preferably in the form of sulfur oxyacid salts, such as sulfates or pyrosulfates.

The titanium dioxide source in the catalyst used in the present invention includes anatase type titanium dioxide, titanium dioxide permanent product, and the like. By using both in combination, it is possible to adjust the specific surface area of the catalytically active component. In the present invention, when the specific surface area is set to 20 TIt/7 or more, preferably 40 to 1507 ii/g, the catalytic activity is further improved.

Non-porous inert supports used in the present invention also include sintered or fused silicates, steatite,
Examples include porcelain, alumina, and silicon carbide. The shape of the carrier is necessarily spherical, cylindrical, ring-shaped, etc., and its equivalent diameter is about 3 to 12 m, preferably about 6 to 10 m. Also,
For cylindrical and ring-shaped items, the height is approximately 3~
"10mm.

Preferably the height is about 4-8#, more preferably about 70-80% of the equivalent diameter. Among these, a ring-shaped one is preferred, and a Lessing ring-shaped one as disclosed in Japanese Patent Publication No. 61-48980 is particularly preferred because it reduces pressure loss and enables high-concentration oxidation. In the case of a ring-shaped carrier, the inner diameter is 2 to 10 m, preferably about 4 to 8 InIn, and for the Lessing ring-shaped carrier 2, a partition wall is provided at the center of the carrier, and the inner diameter is 0.5 m.
A wall thickness of ~2 mm, preferably 0.6-1 Mn is suitable.

After supporting a catalytically active substance, this is heated to form a catalyst. Heating is carried out by thermal decomposition at 300 to 600' C1, preferably in an oxygen atmosphere for 4 to 10 hours.

This catalyst is filled into a reaction tube to form a catalyst layer, and this touch! The indene and/or indane is catalytically oxidized through a molecular oxygen-containing gas mixture containing the indene and/or indane.

Note that this catalyst is filled in the upper layer of the reaction tube (on the upstream side with respect to the flow direction of the raw material gas mixture), and a catalyst that does not contain an alkali metal compound and contains a phosphorus compound, a tin compound, etc. as necessary is filled, and the gas The mixtures may be brought into contact. Further, as the raw material of the present invention, either indene or indane can be used, and they may be used alone or in a mixture. Furthermore, it is also possible to use a mixture of other phthalic anhydride raw materials such as naphthalene and ortho-xylene. In particular, the catalyst of the present invention provides an excellent yield of phthalic anhydride even when phthalic anhydride is produced using naphthalene or orthoxylene as a raw material.
Feedstocks can be switched without converting the catalyst. Note that the purity of the indene or indane used is not particularly limited, and for example, an indene fraction or the like can be used as is, but a purity of 90% or more is preferable.

The reaction conditions are a reaction temperature of 300-400'C (Naitor temperature), preferably 330-3806C, and a raw material concentration of 30-400'C.
809/Nm3 - air, preferably 40-60 bi/Nm
3-Air, space velocity 1. ○○○～8゜○○□hr-+,
Preferably, the same conditions as above can be adopted when using a mixture of 2,000 to 5,000 naphthalene or ortho-xylene.

(Example) Next, the present invention will be explained in more detail by giving examples. In addition, "%" in the following examples is weight % unless otherwise specified.

Examples 1 to 13 (△) Preparation of catalyst Titanium dioxide, ammonium metavanadate, and alkali metal sulfate were added to 7JO of water, thoroughly stirred and emulsified to dissolve water-soluble compounds, and titanium dioxide powder was emulsified or suspended. , it was made into a slurry-like liquid. In the rotary furnace,
A porcelain lessing ring-shaped carrier with a diameter of 8# and a height of 6 mils is inserted, preheated to 200 to 250'C, and the slurry liquid is sprayed onto the carrier while rotating the rotary furnace to form carrier 1.
The catalyst components were supported so that 803 catalyst components were supported per Ω. Next, the mixture was calcined at 550'C for 6 hours while circulating air to obtain a catalyst. Table 1 shows the active component content and specific surface area of the obtained catalyst.

(B) Production of phthalic anhydride A reaction tube with an inner diameter of 25 mm immersed in a nighter bath was filled with the above catalyst layer, and a mixed gas of indene, indane, naphthalene, and air was passed through the tube to produce phthalic anhydride. Raw material concentration is 50g/Nm3, space velocity is 3,
0OOhr'', and the temperature was set to an optimum temperature of 350 to 360°C. The conditions and the yield of phthalic anhydride are shown in Table 1.

Reference Example 1 Example 1~ except that only naphthalene was used as a raw material
Phthalic anhydride was produced in the same manner as in Example 14. The results are shown in Table 1.

(Left below) Table 1 C32SO41,01848 Indan 1
12.52 r/ 2.018 44 11
4.23 〃3.01S &8 114.9
4 // 3.515 85 114.45
r/ 4.015 105 114.76
Rb25041.018 50 111.37
// 1.518 48 112.28#
2.078 46 113.09 #
2.518 55 113.510 /,
3.018 75 113.711 C82
SO43,51585 Indan 115.214
K2304 3.5 15 63 Indane 112.5□ 1 C32SO43,51585 Naphthalene 105
．． 0 (Effects of the Invention) According to the present invention, phthalic anhydride can be produced from indene or indane with good productivity and high yield.

Claims (1)

[Claims] 1. 70-90% by weight of titanium dioxide, 10-30% by weight of vanadium pentoxide, and 0.5-5% by weight of an alkali metal compound.
A molecular oxygen-containing gas mixture containing indene and/or indane is applied to a catalyst layer filled with a catalyst made of a catalytically active component supported on a non-porous inert carrier. A method for producing phthalic anhydride, which comprises contacting and oxidizing it. 2. The method for producing phthalic anhydride according to claim 1, wherein the molecular oxygen-containing gas mixture is a gas mixture containing naphthalene and/or orthoxylene and indene and/or indane.