JPS63267443A - Dehydrogenation and isomerization catalysts for alkyltetralins and usage thereof - Google Patents

Abstract

PURPOSE:To increase the selection efficiency of required isomers by treating Y-type zeolite which is allowed to support one or more of transition metals having atomic numbers 20-30, with alkali to prepare dehydrogenation and isomerization catalysts for alkyltetralins. CONSTITUTION:Y-type zeolite is allowed to support one or more of transition metals having atomic numbers 22-30, and this Y-type zeolite is treated with alkali to obtain dehydrogenation and isomerization catalysts for alkyltetralins. In addition, after the above-mentioned alkali treatment,the zeolite can be further permitted to support one or more of metals such as platinum, palladium, ruthenium and rhodium. In the presence of thee catalysts, alkyltetralins are dehydrogenated and isomerized. This hydrogenation/isomerization reaction allows the alkyl group on the naphthene ring of alkyltetralins to transform at the same time as dehydrogenation. Consequently, the side reaction is restricted and the isomerization is promoted at a high selection rate.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a dehydrogenation/isomerization catalyst for alkyltetralins and a method for dehydrogenation/isomerization of alkyltetralins using the catalyst. , type 1 or 2
Catalysts obtained by alkali treatment of Y-type zeolite carrying more than one type of transition metal, or catalysts further carrying platinum, palladium, etc., and isomer mixtures made of alkylnaphthalenes in the presence of the catalysts. The alkyl tetralin isomer mixture obtained by partial hydrogenation of
The present invention relates to a method of increasing one or more desired isomers present in an alkylnaphthalene isomer mixture whose concentration is below the thermodynamic equilibrium concentration to the thermodynamic equilibrium concentration by dehydrogenation and isomerization.

[Prior art] There are many isomers of alkylnaphthalenes,
Among them, 2,6-dialkylnaphthalene has high industrial added value compared to other isomers.

This is because 2,6-naphthalene dicarboxylic acid obtained by oxidizing 2,6-dialkylnaphthalene is a raw material for polyester having excellent properties and can be used to manufacture synthetic fibers and films.

Regarding other isomers, it is expected that naphthalene dicarboxylic acid obtained by oxidation can be used as a raw material for polymer synthesis, similar to 2,6-dialkylnaphthalene, and various studies are being conducted.

That is, an appropriate method is used to extract the alkylnaphthalene-containing fraction obtained by distillation of petroleum or coal tar-based raw materials,
For example, the target alkylnaphthalene is separated and recovered using a cooling crystallization method, a complex formation method, or an adsorption separation method. The method of increasing the recovery amount of the target alkylnaphthalene by further isomerizing the target alkylnaphthalene is an industrially essential process because the recovery rate of the target alkylnaphthalene is improved.

Many studies have been conducted on the isomerization reaction of alkylnaphthalenes, but none of them are based on AI C23.
, AI Br3, HF, H3PO4, H2SO4, etc., or solid acid catalysts such as silica alumina, H-type mordenite, etc. are used. However, when these acid catalysts or solid acid catalysts are used, even if alkylnaphthalenes are used as they are or alkyltetralins obtained by partial hydrogenation are subjected to the reaction, the reaction cannot be achieved based on the intramolecular rearrangement of the alkyl group. In addition to isomerization reactions, many side reactions such as dealkylation reactions and disproportionation reactions occur, resulting in a low selectivity for the desired isomer.

Therefore, as a method to increase the selectivity of the desired isomer, a fraction containing the desired dimethylnaphthalene isomer at a concentration below the thermodynamic equilibrium concentration is treated with a solid acid catalyst, such as H-type Z A method of isomerizing by contacting with SM-5 (Japanese Patent Application Laid-Open No. 60-38331), in which dimethyltetralin-containing material obtained by partially hydrogenating the above raw material is isomerized by contacting with a solid acid catalyst, for example, silica alumina. A method (Japanese Unexamined Patent Publication No. 48-96569) has been proposed.

However, according to research conducted by the present inventors, even when these solid acid catalysts are treated with the addition of noble metals such as platinum and palladium, side reactions other than the intended isomerization reaction occur frequently, and the target alkyl The disadvantage is that the yield of naphthalene is low.

[Problems to be Solved] In the isomerization reaction of the target alkyltetralin-containing fraction whose concentration is below the thermodynamic equilibrium concentration, dealkylation and disproportionation reactions other than the target isomerization reaction are performed. The present invention provides a dehydrogenation/isomerization catalyst for alkyltetralins that can suppress side reactions such as reactions and has a high isomerization reaction production rate, and a method for dehydrogenation/isomerization of alkyltetralins using the catalyst. .

[Means for Solving the Problems] That is, the present invention consists of: (1) Dehydration of alkyltetralins obtained by alkali treatment of Y-type zeolite carrying one or more transition metals having an atomic number of 22 to 30; Elementary/isomerization catalyst.

■ After alkali treatment of Y-type zeolite supporting one or more transition metals with atomic numbers 22 to 30, one or more transition metals selected from platinum, palladium, ruthenium, and rhodium are added. A catalyst for dehydrogenation and isomerization of alkyltetralins supported on the catalyst.

■ A catalyst prepared by alkali treatment of Y-type zeolite carrying one or more transition metals with atomic numbers 22 to 30, and/or one or more transition metals with atomic numbers 22 to 30. After treating Y-type zeolite supported with alkali, alkyltetralins are treated with hydrogenated zeolite in the presence of a catalyst supported with one or more transition metals selected from platinum, palladium, ruthenium, and rhodium. A method for dehydrogenating and isomerizing alkyltetralins, which is characterized by isomerizing them.

The main points are as follows.

The catalyst of the present invention comprises one of transition metals having an atomic number of 22 to 30.
Y-type zeolite carrying a species or two or more species can be used as it is after being treated with an alkali, but it is also possible to use it as it is after being subjected to a reduction treatment in a hydrogen stream and then being treated with an alkali again, or it can be further treated with alkali, or it can be further treated with platinum, palladium,
It is prepared by supporting one or more of ruthenium and rhodium.

The supported transition metals include titanium, vanadium, chromium, manganese, iron, cobalt, and atomic number 22-30.
Examples include nickel and copper, with nickel being particularly preferred.

The catalyst of this invention contains transition metals having an atomic number of 22 to 30 in Y
After being supported on type zeolite, the supported transition metal is treated with alkali to make it exist in a highly dispersed state on the zeolite, and also neutralizes and poisons the solid acid sites of the zeolite, making it a highly active catalyst. Reactions caused by acid sites are suppressed. Therefore, side reactions such as dealkylation reactions are reduced, and dehydrogenation and isomerization reaction rates are improved.

This catalyst is produced by recovering the target alkylnaphthalene from a concentrated alkylnaphthalene-containing fraction obtained by distillation from petroleum or coal tar, or from synthetic alkylnaphthalenes obtained by alkylating naphthalene, and then partially hydrogenating it. Used for dehydrogenation and isomerization reactions of alkyltetralins. When the purpose is to recover 2,6-dialkylnaphthalene, the 2゜6-dialkylnaphthalene in the raw materials shown above is recovered by an appropriate method to a concentration below the thermodynamic equilibrium concentration, and this is partially hydrogenated. The obtained alkyl tetralins are used.

Unlike the reaction using an acid catalyst, the dehydrogenation/isomerization reaction using the catalyst of the present invention rearranges the alkyl group on the naphthene ring of the alkyltetralin at the same time as dehydrogenation.
Compared to acid catalysts that also cause disproportionation reactions, side reactions are suppressed, the isomerization reaction is promoted with high selectivity, and deterioration of catalyst activity can be suppressed to a low level.

This reaction can be carried out in a gas phase or a liquid phase using a reactor such as a fixed bed or a fluidized bed. Reaction temperature is 250-400
℃, reaction pressure C1-30kg/am2, liquid space velocity 0
．． 9 [Example] Example 1 Sodium Y type After ion-exchanging the zeolite with nickel nitrate, it is immersed in water and stirred for 1 hour while maintaining the pH at 10□5 with an aqueous sodium hydroxide solution in an argon atmosphere. This was filtered, washed with water until the pH of the filtrate became 7.5, and then dried in air at 110°C for 24 hours. This was reduced with hydrogen at 300° C. for 12 hours, and then subjected to the same alkali treatment and drying as above to prepare a nickel-supported catalyst.

This catalyst was placed in a stainless steel reaction tube with an inner diameter of 4.2 mm.
After 1 hour of reduction treatment at 400°C in a hydrogen stream, 0.5 g/hr of 2,6-dinityltetralin was fed together with 150 m2/min of hydrogen, and the reaction was carried out at 320°C. The reaction product was collected 3 hours after starting the reaction and analyzed by gas chromatography. The results are shown in Table 1.

As shown in Table 1, the isomerization selectivity based on intramolecular rearrangement of ethyl groups was about 52%, indicating excellent isomerization activity.

Example 2 Sodium Y-type zeolite is ion-exchanged using nickel nitrate, then immersed in water, and stirred for 1 hour while maintaining the pH at 10.5 with an aqueous sodium hydroxide solution in an argon atmosphere. This was filtered, washed with water until the pH of the filtrate became 7.5, and then dried in air at 110°C for 24 hours. This was subjected to reduction treatment with hydrogen at 300° C. for 12 hours, followed by alkali treatment and drying in the same manner as above. This was further immersed in a palladium ammonia complex solution, left to stand for 24 hours, vacuum dried at room temperature, and calcined at 400° C. for 3 hours to prepare a palladium-supported nickel zeolite catalyst.

This catalyst was placed in a stainless steel reaction tube with an inner diameter of 4.2 mm.
After 1 hour of reduction treatment at 400°C in a hydrogen stream, 0.5 g/hr of 2,6-dinityltetralin was fed together with 150 mg/min of hydrogen, and the reaction was carried out at 300°C. The reaction product was collected 3 hours after starting the reaction and analyzed by gas chromatography. The results are shown in Table 2.

As shown in Table 2, the isomerization selectivity due to intramolecular rearrangement of ethyl groups was about 58%, indicating excellent isomerization activity.

Example 3 The reaction was carried out under the same conditions as in Example 2, except that 2,6-dipurvyltetralin was used as the reaction raw material and the reaction temperature was changed to 280°C. The results are shown in Table 3.

As shown in Table 3, the proportion of products produced by the dealkylation reaction is a little high at about 15%, but the isomerization selectivity is high at about 46%, indicating high isomerization activity. There is.

Comparative Example 1 The reaction was carried out under the same conditions as in Example 3 except that the catalyst was changed to HY type zeolite. The results are shown in Table 4.

As shown in Table 4, the proportion of isopropylnaphthalene, naphthalene and heavy components due to the dealkylation reaction was high, making it difficult to suppress the formation of side reactions.

[Effect of the invention] When an acid catalyst is used for the isomerization reaction of alkyltetralins, it is difficult to suppress side reactions such as dealkylation and disproportionation reactions. In the highly dispersed reduced nickel catalyst, solid acid sites unique to zeolite are sufficiently neutralized and poisoned by alkali treatment. For this reason, de-alcohol b
Side reactions such as Kaki reaction and disproportionation reaction are suppressed, and since nickel and palladium are present on the carrier in a highly dispersed state, isomerization selectivity and reactivity can be maintained at high levels. Moreover, if this catalyst is used, the desired dialkylnaphthalene can be produced with high selectivity and fewer side reactions in the dehydrogenation/isomerization reaction of alkyltetralins.

Claims (3)

[Claims] (1) A catalyst for dehydrogenation and isomerization of alkyltetralins, which is obtained by treating a Y-type zeolite carrying one or more transition metals having an atomic number of 22 to 30 with an alkali. (2) Y-type zeolite supporting one or more transition metals with atomic numbers 22 to 30 is treated with alkali, and then one or more types selected from platinum, palladium, ruthenium, and rhodium are added to the Y-type zeolite. A catalyst for dehydrogenation and isomerization of alkyltetralins that supports a transition metal. (3) A catalyst obtained by treating a Y-type zeolite carrying one or more transition metals with an atomic number of 22 to 30 with an alkali, and/or one or two transition metals with an atomic number of 22 to 30. After alkali treatment of Y-type zeolite supporting one or more species, alkyltetralins are dehydrated in the presence of a catalyst supporting one or more transition metals selected from platinum, palladium, ruthenium, and rhodium. A method for dehydrogenating and isomerizing alkyl tetralins, which is characterized by carrying out elementary and isomerization.