RU2752508C1 - Method for obtaining catalyst and method for obtaining exo-tetrahydrocyclopentadiene in its presence - Google Patents

Abstract

FIELD: chemical industry.SUBSTANCE: invention relates to the field of heterogeneous catalysis, more specifically to the method for isomerization on a heterogeneous catalyst, AlCl3(deposited on silica gel) of endo-tetrahydrodicyclopentadiene into exo-tetrahydrodicyclopentadiene, which, in turn, is the most important component of a liquid high-energy fuel of the JP-10 type. A method for obtaining a catalyst for the production of exo-tetrahydrodicyclopentadiene is proposed, including heating a silica gel with a particle size of 0.31-0.34 mm in a vacuum of 1×10-4T21 to a temperature of 280-330°C for 2-4 hours, cooling it to room temperature, adding anhydrous aluminum chloride to the silica gelб AlCl3with stirring in an argon current, heating the reaction mixture in a vacuum of 1-1. 5×10-4T to a temperature of 78-85°C and holding at this temperature for the time necessary for the interaction of AlCl3with the hydroxyl groups of silica gel to form one covalent bond, and aluminum chloride is taken in an amount that ensures the aluminum content in the catalyst-0.78-3.4б weight percentage. A method for producing exo-tetrahydrodicyclopentadiene by isomerization of endo-tetrahydrodicyclopentadiene in the presence of a catalyst at an elevated temperature in a nonpolar hydrocarbon solvent is also proposed, in which AlCl3(SiO2) containing 0.78-3.4, weight percentage, of AlCl3as the active component used as a catalyst and taken in an amount that provides the ratio of exo-tetrahydrodicyclopentadiene/AlCl3(SiO2) equal to 50-300:1, and the reaction is carried out for 20-535 minutes at a temperature of 17-80°C in the argon medium. Preferably, a solvent selected from the following series is used as a solvent: hexane, heptane, cyclohexane, tetradecane.EFFECT: increase in the yield of the target product, exo-THDCPD, while maintaining high selectivity, the absence of by-products, as well as the reduction of the reaction time and the possibility of simple product isolation.3 cl, 1 tbl, 6 ex

Description

The invention relates to the field of heterogeneous catalysis, more specifically to a method for producing exo-tetrahydrodicyclopentadiene, which, in turn, is the main component of liquid high-energy fuel of the JP-10 type.

For the first time isomerization of endo-tetrahydrodicyclopentadiene (endo-THDCPD) into exo-tetrahydrodicyclopentadiene (exo-THDCPD) was described in [J.F. Eijkman. Chem. Weekblad. 1, 7. 1903]. Endo-exo isomerization was carried out in the presence of sulfuric acid with prolonged heating. However, at the time of the reaction, the structure of the starting compound was not established and this experiment was not repeated. Only in 1946, after the exact structure of endo-THDCPD was established, an assumption was made about the nature of its isomerization in the presence of acid.

Later, the original method for producing exo-TGDCPD by treating the endo-isomer with sulfuric acid was improved. The new method involved the stepwise treatment of the endo-isomer with an acid with a gradual increase in the acid concentration, heating temperature, and reaction time at each step. At the first stage, the ratio of exo / endo isomers reached 2: 1. After the second stage, the exo-isomer content was 99% [U.S. Patent 3,381,046; Esso Research and Engineering Company, April 30, 1968].

A similar method of isomerization of endo-THDCPD is described in [Schneider A, Ware RE, Janoski EJ. Isomerization of endo-tetrahydrodicyclopentadiene to 12 a missile fuel diluent. US: Sunoco Inc R&M Suntech Inc; 1978]. _{Anhydrous AlCl 3 was} used as a catalyst. The solid endo-isomer was dissolved in 1,2-dichloroethane, then the catalyst was added at room temperature, the reaction mixture was cooled to 0 ° C and stirred for 1.5 hours.

As a result, the exo-isomer content in the reaction mixture was 96%.

The general disadvantages of the methods described above are high catalyst loadings, laborious product separation from the mixture, and environmental friendliness.

In [Xing Ε, Zhang X, Wang L, Mi Ζ. Molecular dimensions of tetrahydrodicyclopentadiene 21 isomers and shape selectivity of zeolitic catalysts. Catalysis Communications 22 2005; 6 (11): 737-41] isomerization of endo-THDCPD was carried out using a HY zeolite catalyst (manufactured by Wenzhou Catalyst Co., China). Endo-TGDCPD and zeolite were placed in an autoclave and heated at 195 ° C for 4 hours. The exo-isomer content in this isomerization method was 95%.

A known method of isomerization of endo-THDCPD with cesium-containing heteropolyacid CS _2.5 H _0.5 PW ₁₂ O ₄₀ (CsPW). This catalyst can be regenerated and used repeatedly [Jeong BH, Han JS, Ko SW, Lee JH, Lee BJ. Deactivation and Reuse of Cesium-Containing 24 Heteropolyacid for the Isomerization of THDCPD. Journal of Industrial and Engineering 25 Chemistry 2007; 13 (2): 310-3]. The reaction was carried out at 185 ° C for 8 hours. With the initial use of the catalyst, the exo-isomer yield was 88%.

A common disadvantage of the above methods is the high reaction temperature, which increases the likelihood of the formation of by-products such as adamantane and coke.

One of the newest methods of isomerization is the use of ionic liquids as a reaction catalyst. In [Huang M-Υ, Wu JC, Shieu FS, Lin JJ. Preparation of high energy fuel JP-10 by acidity-17 adjustable chloroaluminate ionic liquid catalyst. Fuel 2011; 90 (3): 1012-7] describes the isomerization of endo-THDCPD using a chloraluminate ion-liquid catalyst (1-butyl-3-methylimidazolium chloride mixed with various amounts of AlCl ₃ ). Isomerization was carried out in a reactor under an inert nitrogen atmosphere with stirring for 3 hours at 50 ° C. The selectivity of the reaction was 98.8%.

Ionic liquids consisting of 1-n-alkyl-3-methylimidazolium chlorides and anhydrous metal halides (AlCl ₃ , CuCl ₂ , FeCl ₃ , ZnCl ₂ ) were used in [Wang L, Zou JJ, Zhang X, Wang L. Isomerization of tetrahydrodicyclopentadiene using 37 ionic liquid: Green alternative for Jet Propellant-10 and adamantane. Fuel 2012; 91 (1): 164-38 9]. The reaction was also carried out in an inert atmosphere with stirring for 30 minutes at 50 ° C. The exo-isomer content in the mixture was 98.3%.

Despite the good results of reactions with ionic liquids as catalysts and the environmental safety of this method, the most important disadvantage is the high cost of reagents, which limits their use in industry.

In [Liu S, Guo JW, Yang CF, Li LH, Cui YH. Synthesis of Al-Containing Mesoporous 27 Molecular Sieves and their Catalytic Performance to Isomerization Reaction of Endo-28 Tetrahydrodicyclo-Pentadiene. Advanced Materials Research 2011; 233-235: 234-7] describes the use of aluminum-containing mesoporous molecular sieves (Al-MCM-41) as catalysts for endo-exo isomerization.

To obtain the catalyst, Al (NO ₃ ) ⋅9H ₂ O was added to an aqueous solution of cetyltrimethylammonium bromide and NaOH. Then tetraethoxysilane was added to this solution with stirring. After stirring for 2 hours, the solution was acidified to pH 5 ~ 6 and stirring was continued for another 2 hours. The mixture was filtered, the resulting solid was washed and dried in an oven at 120 ° C for 3 hours. After calcining for 4 hours at 550 ° C, catalyst A1-MCM-41 was obtained.

Isomerization was carried out in an inert atmosphere under a nitrogen atmosphere. 0.2 g of catalyst was added to 0.2 g of endo-THDCPD, placed in an autoclave and heated for 3 hours at a temperature of 250 ° C and a pressure of P _H2 = 1.5 MPa. As a result, the selectivity of the reaction was 93-96%, and the yield of exo-TGDCPD was 29-46%.

By the totality of essential features, this method can be adopted as the closest analogue of the invention (prototype).

The main disadvantage of this method is the high reaction temperature, and, as a consequence, the formation of a by-product of adamantane in a significant amount. And also low yields of the target reaction product - exo-TGDCPD - no more than 46%.

The technical problem of the present invention is to develop a method for preparing a catalyst and a method for producing exo-tetrahydrodicyclopentadiene, characterized by high conversion of endo-tetrahydrodicyclopentadiene and high selectivity of the method for the target product.

The task is achieved by the fact that a method for preparing a catalyst for producing exo-tetrahydrodicyclopentadiene is proposed, including adding an aluminum salt to the silicon compound with stirring and heating the reaction mixture, in which silica gel with a particle size of 0.31-0.34 mm is used as a silicon compound, which is preliminarily heated in a vacuum of 1 × 10 ^-4 Torr to a temperature of 280-330 ° C for 2-4 hours and cooled to room temperature, as an aluminum salt - anhydrous aluminum chloride AlCl ₃ , stirring is carried out in a stream of argon, heating the reaction mixture - in a vacuum of 1-1.5 × 10 ^-4 Torr to a temperature of 78-85 ° C, and after heating it is kept at this temperature for the time required for the interaction of AlCl ₃ with the hydroxyl groups of silica gel with the formation of one covalent bond, and aluminum chloride take in an amount that provides the aluminum content in the catalyst - 0.78-3.4 wt. %.

At a lower aluminum content, there will be insufficient "acidic" sites to catalyze the reaction, and a higher aluminum content will not be able to interact with hydroxyl groups on the silica gel surface.

A method for the production of endo-tetrahydrodicyclopentadiene by isomerization of exo-tetrahydrodicyclopentadiene in the presence of a catalyst at an elevated temperature in a solvent medium, in which AlCl ₃ (SiO ₂ ) obtained by the method described above is used as a catalyst, is first added to the catalyst with stirring in a stream of argon. a non-polar hydrocarbon solvent, and then endo-tetrahydrodicyclopentadiene is introduced into the mixture, and the starting components are taken in amounts providing the endo-tetrahydrodicyclopentadiene / AlCl ₃ (SiO ₂ ) ratio equal to 50-300: 1, and the isomerization reaction is carried out in an argon atmosphere for 20 535 minutes at a temperature of 17-80 ° C.

As the specified solvent, a solvent selected from the series of hexane, heptane, cyclohexane, tetradecane is preferably used.

The technical result from the implementation of the proposed invention is to increase the yield of the target product - exo-tetrahydrodicyclopentadiene close to quantitative while maintaining high selectivity up to 99% or more and practically no by-products at a temperature of 40-120 ° C and reducing the reaction time to 20 minutes, as well as the ability to easily isolate the product.

The catalyst preparation method is very simple and does not require its isolation, as in the prototype.

This invention is illustrated by the following examples of specific implementation.

Example 1

The method of obtaining exo-tetrahydrodicyclopentadiene by isomerization of endo-tetrahydrodicyclopentadiene was carried out in accordance with the procedure:

The starting reagent - endo-tetrahydrodicyclopentadiene was obtained according to a known method [Nao M, Yang B, Wang Η, et al. Kinetics of liquid phase catalytic hydrogenation of dicyclopentadiene over Pd / C catalyst. J. Phys. Chem. A. 2010; 114: 3811-3817].

For this, a 1000 ml steel autoclave was charged with a mixture of 200.0 g (1.52 mol) of dicyclopentadiene, 4.0 g (2% by weight) 10% Pd / C and 150 ml of diethyl ether. The autoclave was filled with hydrogen to a hydrogen pressure of 40 atm and the reaction mixture was stirred for 2 days at 40 ° C. After completion of the hydrogenation, the reaction mixture was filtered through celite and evaporated in vacuo to give the desired product as a white solid, which, if necessary, can be recrystallized from a mixture of chloroform and methanol.

Get the catalyst for the isomerization process, which is aluminum chloride - AlCl ₃ , deposited on a support of silica gel.

To get it:

- the ampoule is filled with silica gel with a particle size of 0.31 mm and heated in a vacuum (1 × 10 ^-4 Torr) at a temperature of 330 ° C for 2 hours;

- then the ampoule is cooled to room temperature and filled with high purity argon;

- then add anhydrous aluminum chloride to the silica gel and mix.

The resulting reaction mixture is heated in vacuum (1 × 10 ^-4 Torr) to a temperature of 85 ° C and incubated for 3 hours, during which AlCl ₃ quantitatively reacts with the hydroxyl groups of silica gel to release 1 equivalent of HCl. The HCl released as a result of the reaction is removed from the system, being collected in a trap with liquid nitrogen.

After the end of the synthesis, the collected HCl is condensed in a flask with a known volume of water. The resulting solution of hydrochloric acid is titrated with 0.1 Η NaOH solution, which makes it possible to determine the dynamics of the interaction of surface hydroxyl groups of silica gel with aluminum chloride and the number of covalent bonds formed between aluminum chloride and silica gel.

Isomerization of endo-THDCPD is carried out in a reactor with a jacket and a reflux condenser in an argon atmosphere, with a ratio of endo-tetrahydrodicyclopentadiene / AlCl ₃ (SiO ₂ ) equal to 50: 1.

For this, 0.545 g of the obtained catalyst AlCl ₃ / SiO ₂ containing Al in 3.4 wt. %.

The weighed catalyst under an argon atmosphere is transferred to a jacketed reactor pre-filled with argon. Cyclohexane 16.3 ml was added to the catalyst. With stirring, the reactor and the mixture are cooled to 17 ° C. With stirring in a stream of argon, 7.0 ml of a solution of endo-THDCPD (66.6 wt.%) In heptane are added to this mixture. The reaction takes place within 535 minutes at a temperature of 17 ° C.

The exo-isomer content is 99.5% based on gas liquid chromatography.

To isolate the reaction product, the mixture is decanted, the solvent is evaporated on a rotary evaporator. Purified by distillation in vacuo (bp = 83-85 ° C, pressure 11 mm Hg). The yield is 95%.

The data on the composition of the reaction mixture are shown in the table.

Example 2

Getting the starting reagent - endo-tetrahydrodicyclopentadiene is carried out as described in example 1.

The preparation of the isomerization catalyst is carried out as in example 1, but silica gel with a particle size of 0.32 mm is taken, the reaction mixture is heated in vacuum (1 × 10 ^-4 Torr) to a temperature of 83 ° C and incubated for 2.5 hours.

Get a catalyst containing 1.8% wt. aluminum.

Isomerization of endo-tetrahydrodicyclopentadiene to obtain the target product - exo-tetrahydrodicyclopentadiene is carried out as described in example 1, but using the endo-tetrahydrodicyclopentadiene / AlCl ₃ (SiO ₂ ) ratio equal to 100: 1.

Tetradecane is used as a solvent.

0.897 g of the prepared catalyst AlCl ₃ (SiO ₂ ) (Al content 1.8 wt.%) Is weighed in the main box. The weighed catalyst under an argon atmosphere is transferred to a jacketed reactor pre-filled with argon. Tetradecane 16.3 ml was added to the catalyst.

With stirring, the reactor and the mixture are heated to 40 ° C. With stirring in a stream of argon, 12.2 ml of a solution of endo-THDCPD (66.6 wt.%) In cyclohexane are added to this mixture. The reaction takes place within 345 minutes at a temperature of 40 ° C.

The exo-isomer content is 98.6% based on gas liquid chromatography.

To isolate the reaction product, the mixture is decanted, the solvent is evaporated on a rotary evaporator. Purified by distillation in vacuo (bp = 83-85 ° C, pressure 11 mm Hg). The yield is 93%.

The data on the composition of the reaction mixture are shown in the table.

Example 3

Getting the starting reagent - endo-tetrahydrodicyclopentadiene is carried out as described in example 1.

The preparation of the isomerization catalyst is carried out as in example 1, but silica gel with a particle size of 0.34 mm is taken, the reaction mixture is heated in vacuum (1 × 10 ^-4 Torr) to a temperature of 79 ° C and incubated for 3.5 hours.

Isomerization of endo-tetrahydrodicyclopentadiene to obtain the target product - exo-tetrahydrodicyclopentadiene is carried out as described in example 1, but using the endo-tetrahydrodicyclopentadiene / AlCl ₃ (SiO ₂ ) ratio equal to 100: 1.

Hexane is used as a solvent.

Get a catalyst containing 2.8% wt. aluminum.

0.694 g of the prepared catalyst AlCl ₃ (SiO ₂ ) (Al content 2.8 wt.%) Is weighed in the main box. The weighed catalyst under an argon atmosphere is transferred to a jacketed reactor pre-filled with argon. Hexane (16.3 ml) was added to the catalyst. With stirring, the reactor and the mixture are heated to 60 ° C. With stirring in a stream of argon, 14.7 ml of a solution of ecdo-THDCPD (66.6 wt.%) In cyclohexane are added to this mixture. The reaction takes place within 255 minutes at a temperature of 60 ° C.

The exo-isomer content is 97.8% based on gas liquid chromatography.

To isolate the reaction product, the mixture is decanted, the solvent is evaporated on a rotary evaporator. Purified by distillation in vacuo (bp = 83-85 ° C, pressure 11 mm Hg). The yield is 91%.

The data on the composition of the reaction mixture are shown in the table.

Example 4

Getting the starting reagent - endo-tetrahydrodicyclopentadiene is carried out as described in example 1.

The preparation of the isomerization catalyst is carried out as in example 1, but silica gel with a particle size of 0.32 mm is taken, the reaction mixture is heated in vacuum (1 × 10 ^-4 Torr) to a temperature of 80 ° C and incubated for 2 hours.

Get a catalyst containing 2.24% wt. aluminum.

Isomerization of endo-tetrahydrodicyclopentadiene to obtain the target product - exo-tetrahydrodicyclopentadiene is carried out as described in example 1, but using the ratio of endo-tetrahydrodicyclopentadiene / AlCl ₃ (SiO ₂ ) 100: 1.

Cyclohexane is used as a solvent.

Isomerization of endo-THDCPD to obtain exo-tetrahydrodicyclopentadiene is carried out in a reactor with a jacket and a reflux condenser in an argon atmosphere, at a ratio of endo-tetrahydrodicyclopentadiene / AlCl ₃ (SiO ₂ ) 100: 1.

For this, 0.778 g of the prepared catalyst AlCl ₃ / SiO ₂ (Al content 2.24 wt.%) Is weighed in the main box. The weighed catalyst under an argon atmosphere is transferred to a jacketed reactor pre-filled with argon. Cyclohexane 16.3 ml was added to the catalyst.

With stirring, the reactor and the mixture are heated to 80 ° C. With stirring in a stream of argon, 13.7 ml of a solution of endo-THDCPD (66.6 wt.%) In cyclohexane are added to this mixture. The reaction takes place within 20 minutes at a temperature of 80 ° C.

The exo-isomer content according to the results obtained using gas-liquid chromatography is 96.5%.

To isolate the reaction product, the mixture is decanted, the solvent is evaporated on a rotary evaporator. Purified by distillation in vacuo (bp = 83-85 ° C, pressure 11 mm Hg). The yield is 89%.

The data on the composition of the reaction mixture are shown in the table.

Example 5

Getting the starting reagent - endo-tetrahydrodicyclopentadiene is carried out as described in example 1.

The preparation of the isomerization catalyst is carried out as in example 1, but silica gel with a particle size of 0.34 mm is taken, the reaction mixture is heated in vacuum (1 × 10 ^-4 Torr) to a temperature of 78 ° C and incubated for 4 hours.

Get a catalyst containing 1.1% wt. aluminum.

Isomerization of endo-tetrahydrodicyclopentadiene to obtain the target product - exo-tetrahydrodicyclopentadiene is carried out as described in example 1, but using the ratio of endo-tetrahydrodicyclopentadiene / AlCl ₃ (SiO ₂ ) 200: 1.

Heptane is used as a solvent.

In the main box, 0.953 g of the prepared catalyst AlCl ₃ (SiO ₂ ) (Al content 1.1 wt.%) Is weighed. The weighed catalyst under an argon atmosphere is transferred to a jacketed reactor pre-filled with argon. Heptane (16.3 ml) was added to the catalyst. With stirring, the reactor and the mixture are heated to 60 ° C. With stirring in a stream of argon, 15.8 ml of a solution of endo-THDCPD (66.6 wt.%) In cyclohexane are added to this mixture. The reaction takes place within 360 minutes at a temperature of 60 ° C.

The exo-isomer content is 94.4% based on gas liquid chromatography.

To isolate the reaction product, the mixture is decanted, the solvent is evaporated on a rotary evaporator. Purified by distillation in vacuo (bp = 83-85 ° C, pressure 11 mm Hg). The yield is 90%.

The data on the composition of the reaction mixture are shown in the table.

Example 6

Getting the starting reagent - endo-tetrahydrodicyclopentadiene is carried out as described in example 1.

The preparation of the isomerization catalyst is carried out as in example 1, but silica gel with a particle size of 0.32 mm is taken, the reaction mixture is heated in vacuum (1 × 10 ^-4 Torr) to a temperature of 81 ° C and incubated for 3 hours.

Get a catalyst containing 0.78 wt. % aluminum.

Isomerization of endo-tetrahydrodicyclopentadiene to obtain the target product, exo-tetrahydrodicyclopentadiene, is carried out as described in example 1, but using the endo-tetrahydrodicyclopentadiene / AlCl ₃ (SiO ₂ ) ratio of 300: 1.

Cyclohexane is used as a solvent.

1.2 g of the prepared catalyst AlCl ₃ (SiO ₂ ) (Al content 0.78 wt.%) Is weighed in the main box. The weighed catalyst under an argon atmosphere is transferred to a jacketed reactor pre-filled with argon. Cyclohexane 16.3 ml was added to the catalyst. With stirring, the reactor and the mixture are heated to 60 ° C. With stirring in a stream of argon, 21.2 ml of a solution of endo-THDCPD (66.6 wt.%) In cyclohexane are added to this mixture. The reaction takes place within 340 minutes at a temperature of 60 ° C.

The exo-isomer content is 76.2% based on gas liquid chromatography.

To isolate the reaction product, the mixture is decanted, the solvent is evaporated on a rotary evaporator. Purified by distillation in vacuo (bp = 83-85 ° C, pressure 11 mm Hg). Yield 72%.

The data on the composition of the reaction mixture are shown in the table.

Claims (3)

1. A method of obtaining a catalyst for producing exo-tetrahydrodicyclopentadiene, comprising adding an aluminum salt to the silicon compound with stirring and heating the reaction mixture, characterized in that silica gel with a particle size of 0.31-0.34 mm is used as the silicon compound, which is preheated in a vacuum of 1 × 10 ^-4 Torr to a temperature of 280-330 ° C for 2-4 hours and cooled to room temperature, as an aluminum salt - anhydrous aluminum chloride AlCl ₃ , stirring is carried out in a stream of argon, heating the reaction mixture - in vacuum 1-1.5 × 10 ^-4 Torr to a temperature of 78-85 ° C, and after heating, it is kept at this temperature for the time required for the interaction of AlCl ₃ with the hydroxyl groups of silica gel with the formation of one covalent bond, and aluminum chloride is taken in an amount providing the aluminum content in the catalyst - 0.78-3.4 wt.%. 2. A method of obtaining exo-tetrahydrodicyclopentadiene by isomerization of endo-tetrahydrodicyclopentadiene in the presence of a catalyst at an elevated temperature in a solvent medium, characterized in that AlCl ₃ (SiO ₂ ) obtained by the method according to claim 1 is used as a catalyst, to the catalyst first with stirring in A non-polar hydrocarbon solvent is added to the flow of argon, and then endo-tetrahydrodicyclopentadiene is introduced into the mixture, and the initial components are taken in amounts providing the ratio of endo-tetrahydrodicyclopentadiene / AlCl ₃ (SiO ₂ ) equal to 50-300: 1, and the isomerization reaction is carried out in an argon atmosphere in for 20-535 minutes at a temperature of 17-80 ° C. 3. A method according to claim 2, characterized in that a solvent selected from the series: hexane, heptane, cyclohexane, tetradecane is used as said solvent.