JPS5889945A - Selective oxidatative catalyst for hydrogen in dehydrogenated product of ethyl benzene - Google Patents

Abstract

PURPOSE:To enable oxidation of hydrogen with high selectivity under the temp. for oxidizing hydrogen by using catalyst contg. tin oxide. CONSTITUTION:In adding gas contg. oxygen to the dehydrogenated product to oxidiz hydrogen in the dehydrogenated product selectively and catalytically at 500-700 deg.C in the stage of producing styrene by dehydrogenating ethyl benzene, a tin compd. containing >=50wt% in terms of tin oxide is used as a catalyst. The tin compd. is exemplified by tin halide, tin oxyhalide, halogenated ammonium tin, tin sulfate, tin hydroxide, etc.

Description

Detailed Description of the Invention The present invention relates to a catalyst used in the production of styrene. More specifically, the present invention relates to a catalyst used in the production of styrene. It relates to a catalyst that oxidizes to

By using the catalyst of the present invention, hydrogen in the ethylbenzene dehydrogenation reaction product can be selectively oxidized, and styrene can be produced economically.

The catalyst of the present invention (optionally, the dehydrogenation reaction product when the corresponding styrene substituted product is obtained by dehydrogenation of an alkyl aromatic compound, or the dehydrogenation reaction product of the corresponding olefin or diolefin by dehydrogenation of butane butene, impentane, isopentene, etc.) It can also be applied in production, and is particularly suitable for selectively oxidizing hydrogen in the ethylbenzene dehydrogenation reaction product.

Generally, the dehydrogenation reaction is an endothermic reaction, so if the reaction system is not heated, the reaction will automatically slow down. In the dehydrogenation reaction of ethylbenzene, in order to carry out the dehydrogenation reaction industrially, it is necessary to have sufficient economical heat equipment to allow the dehydrogenation reaction to proceed to the maximum extent possible, but this is not an easy task. .

Conventionally, water vapor has been introduced secondarily as the heat equipment. Also, the reaction mixture whose temperature has been reduced is
A method is used in which the material is reheated by an appropriate method before entering the next reaction section. However, these methods are not economically advantageous and involve technical inclinations. The proposed device that solves these problems selectively oxidizes and burns the hydrogen in the gas produced by the dehydrogenation reaction of ethylbenzene by introducing oxygen into the reaction product gas, thereby reducing the temperature of the nuclear reaction product. As the temperature of the gas increases, the chemical equilibrium that produces styrene through the dehydrogenation reaction of ethylbenzene is
It is disclosed that by selectively oxidizing and burning hydrogen in the dehydrogenation reaction product gas, the chemical equilibrium is shifted in the direction in which styrene is produced. Selection of hydrogen in the dehydrogenation reaction product gas For the target oxidation, it is required to selectively oxidize only the hydrogen in the reaction product gas without causing an oxidation reaction of the organic substances in the raw material ethylbenzene and the target styrene. Furthermore, considering that the dehydrogenation reaction of ethylbenzene generates heat at 500 to 700° C., preferably 600° C., the catalyst must also have sufficient heat resistance. In practice, in order to maintain a high single-stream yield of styrene, the temperature of the dehydrogenation reaction must be set at 650°C.
It is desirable to maintain the temperature at a relatively high temperature around °C. Further, the oxygen-containing gas is supplied only to the oxidation catalyst layer excluding the dehydrogenation catalyst layer. When oxygen remains until the next dehydrogenation catalyst layer,
It is known that dehydrogenation catalysts deteriorate, so all oxygen is
It needs to be consumed in the oxidation catalyst layer. In addition, since the dehydrogenation catalyst is usually a potassium-promoted iron oxide catalyst, it is known that this potassium scatters little by little and adheres to downstream objects, so the oxidation catalyst is not exposed to chemical or physical damage caused by this potassium compound. You have to endure poison. Needless to say, since oxidation catalysts are used in mass-produced chemicals such as styrene, they are also required to be inexpensive.

The above-mentioned Japanese Patent Application Laid-Open No. 1989-1999, which is known as a selective hydrogen oxidation catalyst,
The reduced platinum-supported zeolite catalyst disclosed in Japanese Patent No. 56930 is presumed to have the following drawbacks. That is, some of the zeolite catalysts have poor hydrogen oxidation selectivity at relatively high temperatures of about 650°C. Additionally, zeolite catalysts are generally known to have poor heat resistance.
If used for a long time at a high temperature of about 650°C, the catalyst performance may deteriorate. Furthermore, in zeolite catalysts with small pore diameters, there is a high possibility that the pores will be closed due to the scattering of potassium compounds and carbon, and this problem is particularly important when used for a long period of one year or more. becomes. Furthermore, since platinum is used, the catalyst is expensive, which is a serious drawback from an industrial perspective.

The present inventors conducted extensive studies in search of a catalyst that does not have the above-mentioned drawbacks, and found that only when using a catalyst containing tin oxide, the hydrogen oxidation reaction temperature condition of a relatively high temperature of 650 ° C. They also discovered a catalyst for the selective oxidation of hydrogen during the ethylpequine dehydrogenation reaction, which oxidizes hydrogen with excellent selectivity, has excellent heat resistance and toxicity resistance, and is inexpensive, and completed the present invention.

In other words, in the present invention, when styrene is produced by dehydrogenating ethylbenzene, an oxygen-containing gas is added to the dehydrogenation product, and the process is carried out at a temperature in the range of 500 to 700°C.
Provided is a catalyst for selective catalytic oxidation of hydrogen in an ethylbenzene dehydrogenation reaction product, characterized in that the catalyst contains tin oxide. It is something to do.

The tin oxide catalyst used in the present invention can be prepared by a conventional method. As raw materials, various tin compounds that become tin oxide by firing are used. for example,
Water-soluble or insoluble inorganic tin compounds such as tin halide, tin oxyhalide, ammonium halide, tin sulfate, tin sulfide, nitric acid, carbonic acid, perchloric acid, tin hydroxide, tin oxide, etc. Organic water compounds such as , oxalic acid moiety, acetic acid moiety, and formic acid moiety can be used. A preferred method is to dissolve an inorganic salt of tin such as tin chloride in water, precipitate it in aqueous ammonia or alkali-containing water to form a hydroxide, and then calcinate it to form an oxide.

It is desirable that the hydroxide and/or oxide be formed into a hydroxide and/or oxide, then granulated and calcined. Firing temperature is 650~
1,100℃ or less, preferably 700 to 1,000℃
Good.

Compounds of other elements may be added to the catalyst of the present invention as long as they do not significantly affect its performance. Elements that can be added include Na, K, Rb5Cs%Be%
Mg, Ca s Sr %Ba %B s Al-sQ
a,・,Tt,P,Sbt Bi%S% Se%Te
%Y1Ti, Zr, Hfs, V,, Nb,'=
・Ta, Cr, No, W1 City, Fe%Cos
Nts Cut Znq^g, Cd%Rn.

In particular, 4. ribs, rRll, Ir, Pt%Re, St. Ca%5r1Ba, 8% ht, Si%
Ti.

Zr%Na%, Fe, Wjn, Zn, etc. are 1
It may be contained in an amount of 0% by weight or less, and may be useful for purposes such as improving catalyst strength. Furthermore, 1, Si
, At%Mg, Ca, Ti%Zr, etc. are 50
The tin oxide catalyst of the present invention, which may contain up to 50% by weight, preferably contains tin oxide as a main component, and usually 50% by weight or more as tin oxide,
Preferably 70% by weight or more, particularly preferably 80% by weight
The tin oxide catalyst of the present invention preferably contains the following:
Of course, a catalyst in which tin oxide is supported on a carrier can also be used, and T'+ 1Zr, 8, which is commonly used as a carrier, can also be used.
Oxides of 1sA, Ca, Ca, etc., and mixtures and composites thereof are used. As a method for supporting the carrier, a conventional impregnation method, a coating method, etc. can be used. In this case, the content of tin oxide is 50% by weight or less per catalyst, but the catalyst composition listed above refers to the content of tin oxide in the supported active material. 500-6 on the catalyst to show the advantage of
Ethylbenzene, styrene, water vapor, hydrogen, and air were supplied in a temperature range of 50°C to carry out an oxidation reaction, and the gas produced by this reaction was analyzed. - The mixing ratio of ethylbenzene, styrene, hydrogen, etc. A case in which 20 to 50% of ethylbenzene was converted to styrene in the apparatus was selected based on assumption.

The reactor used in the reactions of Examples and Comparative Examples had an inner diameter of 20
A quartz reaction tube with an effective volume of SOW/ was used, and the catalyst 2d was diluted with a 5 N/ diluent (Raschchig ring sized to the same size as the catalyst) and placed in the center of the reaction tube. The mixing ratio of ethylbenzene (sometimes abbreviated as EB), styrene (sometimes abbreviated as SM), hydrogen, air and steam supplied to the reactor is selected as per the example shown below. Circle. In the feed gas, CO and Co
Since t is not included at all, CO in the reaction tube outlet gas
The amounts of ethylbenzene and styrene burned were calculated by analyzing the amounts of ethylbenzene and styrene.

The analysis used gas chromatography. The reaction results were calculated as follows.

Example 1 Stannous chloride (5nC1*2HzO) 90.24 t
was dissolved in 1,000 ml of water, and while stirring, 3N ammonia water was added to precipitate tin hydroxide (the addition of ammonia water was stopped when the pH exceeded 7).

The nine precipitates obtained were filter-washed and dried at 120°C for 3 hours. Thereafter, it was baked in a Matsufuru furnace at 800°C for 3 hours, and the resulting powder was kneaded with a small amount of water in a crusher to form an extrudable paste, which was then extruded to a size of 3 mm in diameter.

This was fired again in the Matsufuru furnace at 800°C for 3 hours.
The obtained catalyst was crushed and sized to a size of 10 to 20 meshes. This was filled into the aforementioned reaction tube as described above. A mixture whose ratio of substances entering the reactor was as shown in Table 1 was supplied at a space velocity of 24.000 Hr"-', and the mixture was as shown in Table 2. The results were obtained.The reaction time was 6 hours for each.0 (The following margins are blank) Table 1 Table 2 Proportion of the supplied 9 SM-EB that was lost by combustion.

The reaction was carried out in the same manner as in Example 1, except that the materials entering the reactor were as shown in Table 3, and the space velocity was 25,500 Hr-'. The results are shown in Table 4.

Table 3 Table 4 Example 3 The reaction was carried out in the same manner as in Example 1 except that the substances entering the reactor were as shown in Table 5 and the space velocity was 15,652 Hr-' (this reaction The conditions were the same as in Example 4 of JP-A No. 49-56930, and the results are shown in Table 6.

Table 5 Table 6 Comparative Example 1 Fill the reaction tube with only Laschich ring and set the reaction temperature to 6.
The reaction was carried out in the same manner as in Example 1 except that the temperature was 00°C. The results are shown in Table 7.

Comparative Example 2 A reaction was carried out in the same manner as in Comparative Example 1, except that a commercially available 5heu-1os catalyst was used as a dehydrogenation catalyst.

The results are shown in Table 7.

Comparative example 3 Zinc nitrate (Zn(Nus)z・6H20) 118.9
A zinc oxide catalyst was obtained in the same manner as in Example 1 except that 6f was used. A reaction was carried out in the same manner as in Comparative Example 1 using this catalyst.

The results are shown in Table 7.

Comparative Example 4 Chromium nitrate [Cr(NOx)-9a2o]-so
A chromium oxide catalyst was obtained in the same manner as in Example 1 except that , o 4 f was used. A reaction was carried out in the same manner as in Comparative Example 1 using this catalyst. Comparative example 5 with binding shown in Table 7 Ferric nitrate ((Fe(NOx)31"9HzO) ・8
Fe was prepared in the same manner as in Example 1 except that 0-80 f was used.
A 20a catalyst was obtained. This was heated to 500℃, 'HxO/H2
Reduction treatment was performed for 1 hour with a mixed gas of = 12 (molar ratio) to obtain a Fe5Oa catalyst. This was used to react in the same manner as in Comparative Example 1.

The results are shown in Table 7.

Comparative Example 6 Titanium hydroxide obtained by precipitating TiCl2 with aqueous ammonia and ammonium paratungstate were kneaded, extruded, and fired at 800°C for 3 hours to obtain TiO2:
An oxide mixture catalyst having a composition ratio of WO3=9:1 was obtained. Using this catalyst, a reaction was carried out in the same manner as in Comparative Example 1. The results are shown in Table 7.

Comparative Example 7 Calcium hydroxide and molybdic acid (H2Mo 04・I
A small amount of water was added to (zO) and kneaded, and after molding, it was calcined in a Matsufuru furnace at 800°C for 3 hours to obtain a CaO-Mova (molar ratio 1:1) catalyst. A reaction was carried out in the same manner as in Comparative Example 1 using this catalyst. The results are shown in Table 7.90 Comparative Example 8 α-At20. A reaction was carried out in the same manner as in Comparative Example 1 using a catalyst on which 10 ppm of platinum was supported. The results are shown in Table 7.

Comparative Example 9 A catalyst was prepared and a reaction was carried out in the same manner as in Comparative Example 8, except that palladium was used. The results are shown in Table 7. Table 7 Comparative Example 10 Molecular sieve similar to Example 8 of JP-A-49-56930 (zeolite 4A type, part of the sodium was cation exchanged with platinum and potassium) 5.9
Weight: Na, 9.5 Weight: Sea urchin, 0.08% by weight
The reaction was carried out in the same manner as in Example 1 and Example 3, except that Pt-containing Pt-containing material was prepared and used. The results are shown in Table 8.

Table 8 Example 4 Table 9 shows the results of using the catalyst of Example 1 for a long time under the same conditions as Example 1.

Table 9 (Reaction temperature: 650° C.) Example 512 tm A catalyst layer was prepared in which a dehydrogenation catalyst and an oxidation catalyst of the present invention were combined in series as shown in Book 4.

The reaction tube l is made of stainless steel with an inner diameter of 27 cm, and there are 4
It has a thermocouple storage tube 2 made of stainless steel with a diameter of 1φ. The reaction tube 1 was heated in the w1 air furnace 3 and maintained at a predetermined temperature. Air is transferred to a dehydrogenation catalyst layer (5 hell 105, particle size 8-1
2 meshes, 3QI/) 5 and an oxidation catalyst layer 6 (S002 catalyst 1.10 to 20 meshes, 2 ml was diluted with Raschchilling to give a total of 5.7 d). The composition of the dehydrogenation reaction product gas that has passed through the dehydrogenation catalyst layer 5 is
17 were collected and analyzed by gas chromatography.

Ethylbenzene from tube 8, water from tube 9 H20/E
B = 6.05, LH8H(EB) = 1.02, feed E B = 250.7 m moL/hr, feed H20 = 1516.7 m moL/hr. The temperature of the dehydrogenation catalyst layer 5 was maintained at 600°C.

It was confirmed by gas chromatographic analysis of the reaction product gas collected from the tube 7 that the raw material gas that passed through the dehydrogenation catalyst layer 5 had the following composition as a dehydrogenation reaction product gas at point P.

P point composition unreacted EB: 104 mmot/hrSM
: 136 # Toluene : 5.9 Ibenzene :
3.2 #Hydrogen: 188
# Methane: 5.6 # - Carbon oxide 1.4 # Carbon dioxide:
14.3 #Ethylene:
0.4 m mat/hr Ethane: 0.2 H,O: 1440 Air was fed through tube 4 at a rate of 224 m mo/,/hr. The reaction temperature of the oxidation catalyst layer 6 is 610 to 62
The temperature was kept at 0°C and the reaction time was 9 hours.

The gas that passed through the oxidation catalyst layer 6 was collected at the reaction tube outlet 1o and analyzed. The following results are shown in Table 10.

Table 10

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of one embodiment of the present invention, and FIG. 2 is a sectional view of a reaction apparatus. Fig. 1 1...Steam supply pipe 2...(EB+Steam) supply pipe 3...Oxygen-containing gas supply pipe A□, A2, A3, A4...Dehydrogenation catalyst layer B1, B2
, B2... Oxidation catalyst layer Fig. 2 1... Reaction tube 2... Thermocouple protection tube 3... Electric furnace 4... Air supply pipe 5... Dehydrogenation catalyst layer 6... Oxidation catalyst layer 7... Analysis gas collection tube 8... EB supply pipe 9... H20 supply pipe 10... Outlet

Claims (1)

[Claims] When producing styrene by dehydrogenating ethylbenzene, adding an oxygen-containing gas to the dehydrogenation reaction product,
A catalyst for selectively catalytically oxidizing hydrogen in a skeleton dehydrogenation reaction product in a temperature range of 500 to 700°C, the catalyst containing tin oxide in an ethylbenzene dehydrogenation reaction product. selective hydrogen oxidation catalyst.