RU2536043C1 - Catalyst for hydroamination of acetylene hydrocarbons and method of hydroamination of acetylene hydrocarbons with thereof application - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: catalyst contains nanoparticles of metallic gold on carrier - mesoporous zeolite-like silicate MCM-41, modified with ionic liquid, with the following component ratio, wt %: Au - 1-5, ionic liquid - 5-20, carrier - the remaining part. As ionic liquid it contains 1-n-butyl-3-methylimidazolium hexafluorophosphate or 1-n-butyl-3-methylimidazolium tetrafluoroborate. Also claimed is method of hydroamination of liquid acetylene hydrocarbons with amine with application of claimed catalyst and carrying out process under conditions of catalyst SHF-heating in medium of organic solvent at temperature 100-150°C and molar ratio amine:acetylene hydrocarbon, equal 1-2:1. Toluene, styrene, dimethylformamide or said ionic liquid is used as organic solvent. Aniline or morpholine is used as amine.

EFFECT: reduction of time of hydroamination reaction due to application of claimed three-component catalyst and, a result increase of the process productivity with preservation of high degree of conversion of acetylene hydrocarbons, in all examples by claimed invention SHF-radiation with very low power is used instead of thermal reactor heating, which results in reduction of energy consumption.

6 cl, 2 tbl, 11 ex

Description

The invention relates to the field of catalytic technologies for the processing of hydrocarbon feedstocks and relates, in particular, to a catalyst for the hydroamination of acetylene hydrocarbons and to a process for the hydroamination of acetylene hydrocarbons using this catalyst. The method is based on the hydroamination of acetylene hydrocarbons with amines to produce valuable products.

Acetylene hydrocarbons (c / c) are a by-product of the production of olefin monomers, obtained mainly by pyrolysis of a wide fraction of light hydrocarbons in tube furnaces. Polymer manufacturers have high demands on the degree of purification of olefins from acetylene hydrocarbons. The latter, therefore, do not find adequate application.

Styrene, as well as ethylene, is a valuable industrial raw material - the initial monomer for the synthesis of polystyrene and rubbers. Styrene is obtained by catalytic dehydrogenation of ethylbenzene, and a certain amount of phenylacetylene is inevitably formed together with the target olefin monomer - its content in crude styrene is about 2-3% [NA Khan, S. Shaikhutdinov, H.-J. Freund // Acetylene and ethylene hydrogenation over supported Pd-Ag model catalysts // Catalysis Letters, 2006, v. 108, No. 3-4, p. 159-164; BA Wilhite, MJ McCready, A. Varma // Kinetics of phenylacetylene hydrogenation over Pt / Al ₂ 0 ₃ catalyst // Ind. Eng. Chem. Res., 2002, v.41, p. 3345-3350]. During the polymerization of styrene, even such an “impurity” content of acetylene hydrocarbon quickly poisons the catalysts and sharply reduces the quality of the resulting polymers. In this regard, the content of acetylene impurities in the feed polymerization monomer should be reduced to the minimum acceptable value.

One of the effective methods for the utilization of acetylene hydrocarbons is the hydroamination reaction, leading to the production of valuable products - imines, which upon further hydrolysis lead to the formation of valuable ketones. From literary sources it is known [C W. Kruse, R.F. Kleinschmidt // Ethylidenimines by the Reaction of Acetylene with Primary Aliphatic Amines // J. Am. Chem. Soc, 83, 213, 1961] that ethylideneimines are formed from acetylene and primary aromatic amines, for example aniline, during the hydroamination in the presence of zinc or cadmium acetate under pressure at 120-140 °.

R-NH ₂ + CH≡CH → CH ₃ CH = NR

However, due to the fact that zinc and cadmium acetates are readily soluble in aniline, this method relates to a homogeneous catalytic process. In addition, in this case, as in any homogeneous catalytic process, the problem arises of separating the catalyst from the reaction mixture.

According to published data, the difficulties encountered in the practical implementation of hydroamination are primarily due to the fact that direct nucleophilic addition of amines via a C-C multiple bond is complicated by a number of kinetic and thermodynamic factors [F. Pohlki, S. Doye // The catalytic hydroamination of alkynes // Chem. Soc. Rev. 32 (2003) 104]. Moreover, the hydroamination of alkynes is a thermodynamically more preferred process [M. Beller, J. Seayad, A. Tillack, H. Jiao, Angew. Chemie, 43 (2004), 3368].

Over the past few years, research has been intensively developed involving the use of complexes and gold nanoparticles as catalysts for the hydroamination of unactivated alkenes, alkynes, allens and 1,3-dienes [E. Genin, P.-Y. Toullec, S. Antoniotti, C. Brancour, J.-P. Genet, V. Michelte // Catalytic Markovnikov and anti-Markovnikov Functionalization of Alkenes and Alkynes: Recent Developments and Trends // J. Am. Chem. Soc. 128 (2006) 3112]. Hydroamination of alkynes is carried out in the presence of heterogeneous catalytic systems containing metal cations (eg, Ag ⁺ , Cu ²⁺ , Zn ²⁺ Pd ²⁺ ) supported on carriers containing acid sites [N. Lingaiah, N. Seshu Babu, K. Mohan Reddy, PS Sai Prasad, I. Suryanarayana // Room Temperature Au (I) -Catalyzed exo-Selective Cycloisomerization of Acetylenic Acid // Chem. Commun. 3 (2007) 278].

The disadvantage of all the described catalytic systems for hydroamination reactions is their insufficiently high activity, the process requires considerable time to achieve alkyn conversion of not less than 90%.

Closest to the proposed invention in composition is the catalyst described in [A. Corma, P. Concepción, I. Domínguez, V. Fornés, M.J. Sabater // Gold supported on a biopolymer (chitosan) catalyzes the regioselective hydroamination of alkynes Journal of Catalysis, 251 (2007) 39]. The catalyst contains gold nanoparticles deposited on silica gel modified with chitosan and exhibits high activity in the intermolecular hydroamination of a number of alkynes using aniline. However, to achieve this conversion, a reaction time of at least 20 hours is required. The hydroamination process is carried out under thermal heating at T = 100 ° C with an acetylene hydrocarbon: aniline ratio of 1: 1. The conversion of acetylene UV near 100% is achieved only in 22 hours of the reaction in a static reactor with stirring (as examples, the conversion of octin-1 was 92%, and phenylacetylene - 96%. The calculated value of TON (in mmol converted phenylacetylene to mmol Au per hour) was 58.

A significant disadvantage of the known catalyst is its insufficiently high activity, and in order to achieve high conversion of acetylene hydrocarbons, a very long reaction time of the reaction mixture is required (at least 20 hours). In addition, the formation of heavy condensation products reduces the yield of the target products.

The present invention is the creation of an effective catalyst for the hydroamination of acetylene hydrocarbons with amines and the development of a method for the hydroamination of acetylene hydrocarbons with amines using the proposed catalyst, which allows to reduce the reaction time and, as a result, to increase the productivity of the process while maintaining a high degree of conversion of acetylene hydrocarbons.

To achieve this goal, a catalyst is proposed for hydroamination of liquid acetylene hydrocarbons with an amine, including metal gold nanoparticles on a support, characterized in that it contains a mesoporous zeolite-like silicate MCM-41 modified with ionic liquid (IL) in the following ratio of components, wt. %:

Au 1-5 ionic liquid 5-20 carrier rest

The catalyst contains metallic gold nanoparticles with an average size of 2-60 nm on a mesoporous zeolite-like silicate MCM-41 with a specific surface area of about 1000-1200 m ² / g and a mesopore volume of about 1.2-2.0 cm ³ / g.

As an ionic liquid, the catalyst contains 1-n-butyl-3-methylimidazolium hexafluorophosphate - [BMIM] PF ₆ (IL-1) or 1-n-butyl-3-methylimidazolium tetrafluoroborate - [BMIM] BF ₄ (IL-2).

A method is also proposed for hydroamination of liquid acetylene hydrocarbons with an amine using the proposed catalyst, the process being carried out under microwave heating (activation) of the catalyst in an organic solvent at a temperature of 100-150 ° C and a molar ratio of amine: acetylene hydrocarbon equal to 1-2: one.

The organic solvent used is toluene, styrene, dimethylformamide or an ionic liquid, mainly 1-n-butyl-3-methylimidazolium hexafluorophosphate or 1-n-butyl-3-methylimidazolium tetrafluoroborate.

As the amine, for example, aniline or morpholine is used.

The process of hydroamination of acetylene hydrocarbons with amines can be carried out both in a static reactor with a mass ratio of acetylene hydrocarbon: the proposed catalyst is 1-4: 1, and in a flow reactor with a fixed catalyst bed at a mass feed rate of liquid feed in the range of 0.5-1 h ^-1 , while the feed mixture contains acetylene hydrocarbon and amine dissolved in a solvent at a concentration of up to 80% in the solvent.

The hydroamination process is carried out in the presence of gold-containing catalysts, self-heating under the influence of microwave radiation, in the form of three-component catalysts Au / IL / MSM-41, where the mesoporous zeolite-like silicate MCM-41 is pretreated and contains ionic liquids on the surface. The possibility of heating such catalysts under microwave radiation is due to the fact that ionic liquids deposited on a carrier are polar molecules. In addition, ionic liquids are preliminarily introduced into the catalyst to stabilize gold nanoparticles on the surface of MCM-41.

It is possible to use non-polar organic solvents as a solvent, for example, aromatic hydrocarbons such as toluene, styrene, etc.

In order to increase the efficiency of the process, it is carried out in an environment of a polar organic solvent, which is independently heated under the influence of microwave radiation to temperatures of 100-150 ° C. In this case, polar organic solvents are used, for example, dimethylformamide (DMF) or others, as well as various ionic liquids. When using Au / IL / MSM-41 catalysts and polar organic solvents, the reaction heat can be supplied both to the catalyst and to the solvent, since they are simultaneously able to accumulate the thermal energy of microwave radiation.

As acetylene hydrocarbons, linear hydrocarbons such as hexine, heptin, octine, or aromatic acetylene hydrocarbons such as phenylacetylene (FA), diphenylacetylene (DPA), etc. are used.

To heat the catalyst and the reaction mixture, a resonator-type microwave installation is used with an operating frequency of 2-8.3 GHz, preferably 5.7 GHz, with an adjustable power in the range of 1-10 W, the selection of which can provide a given process temperature. Also for heating can be used household microwave ovens with a frequency of 2.45 GHz.

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и др., и широко используются в органическом синтезе и катализе как растворители, однако, в открытой и патентной литературе отсутствуют примеры использования ионных жидкостей в сочетании с гетерогенными катализаторами в процессах гидроаминирования алкинов.Ionic liquids are low-temperature melts of organic salts containing an organic cation with a quaternized nitrogen atom (alkyl pyridinium, alkylimidazolium, alkylpyrrolidinium, alkylammonium) and an inorganic anion of the type

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and others, and are widely used in organic synthesis and catalysis as solvents, however, in the open and patent literature there are no examples of the use of ionic liquids in combination with heterogeneous catalysts in the hydroamination of alkynes.

Microwave heating of the reaction mixture is used in organic synthesis and catalysis [B. Toukoniitty, J.P. Mikkola, D.Yu. Murzin, T. Salmi // Utilization of electromagnetic and acoustic irradiation in enhancing heterogeneous catalytic reactions // Applied Catal. A. Gen., 2005, v. 279, p.1-22]. However, in the open and patent literature there are no examples of the use of microwave activation of heterogeneous catalysts in the hydroamination of alkynes.

The invention is illustrated by the following examples:

Example 1. Preparation of Au / IL-1 / MSM-41 catalyst

The catalyst is prepared as follows. An ionic liquid - 1-butyl-3-methylimidazolium hexafluorophosphate (IL-1) is preliminarily applied to the carrier (MCM-41 with a BET specific surface area of 1200 m ² / g, mesopore volume 1.3 cm ³ / g and pore diameter ≤50 nm) ) For this, 12 g of a pre-evacuated carrier (80 ° C, 5 h) were treated with 2.4 g of an ionic liquid dissolved in absolute methanol (20 ml) with stirring for 0.5 h. Then, the solvent was distilled off using a water-jet pump (80 ° C, 4 h).

Gold nanoparticles are applied to a carrier treated with an ionic liquid (12 g) from a solution of the HauCl ₄ × 4H ₂ O precursor (0.13 g) in methanol (20 ml) by the method of impregnation of the carrier by moisture capacity at 20 ° C. After applying gold as a complex compound, the catalyst is dried in air with constant stirring, and then under reduced pressure (10 ^-3 Torr) at 100 ° C for 4 hours. The reduction of the HauCl ₄ precursor to gold nanoparticles is carried out by treating HauCl ₄ / IL / MSM-41 with sodium borohydride (NaBH ₄ ) in methanol at 20 ° C. To the catalyst containing the gold complex, 30 ml of methanol are added at 20 ° C., and then a solution of NaBH ₄ (0.14 g in 30 ml of methanol) is slowly added dropwise. The resulting mixture was stirred on a magnetic stirrer at 20 ° C for 0.5 h, filtered and then the catalyst was dried under reduced pressure using a water-jet pump at 90 ° C for 6 hours. Next, the gold-containing Au / IL / MSM-41 catalyst is evacuated using an oil pump (10 ^-3 Torr, 150 ° C, 8 hours).

The gold content in the catalyst was 5 wt.%. The content of the deposited ionic liquid is 20 wt.%.

Example 2. The catalyst is prepared according to example 1, except that other quantities of the HauCl ₄ × 4H ₂ O precursor and ionic liquid are taken. The content of gold and IL-1 in the catalyst amounted to 1 and 5 wt.%, Respectively.

Example 3. Preparation of Au / IL-2 / MSM-41 catalyst

The catalyst is prepared according to example 1, except that another ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate (IL-2), is preliminarily applied to the MCM-41 support, and the amount of the HauCl ₄ × 4H ₂ O precursor is taken less.

The content of gold and IL-2 in the catalyst amounted to - 2 and 10 wt.%, Respectively.

Examples 4-8. Hydroamination under static conditions

The hydroamination of acetylene UV was carried out at a temperature in the range of 100-150 ° C in a static reactor (glass tube with a diameter of 1 cm and a volume of 10 ml). The catalyst charge was 0.2 g, and the total volume of the reaction mixture (together with the solvent and catalyst) was 2 ml. Mixing of the reaction mass was carried out due to convective motion of the liquid under conditions of its heating. A thermocouple controlling the reaction temperature was placed directly in the reaction mass.

The process conditions under static conditions (temperature, solvent used and process time), as well as molar and mass ratios of reactants and catalysts are presented in table 1.

Example 9-10 Hydroamination in a flow reactor

The hydroamination of acetylene UV was carried out at a temperature in the range of 100-110 ° C in a flow reactor (quartz tube with a diameter of 1 cm) at a mass feed rate in the range of 0.5-1 h ^-1 (up to 80 wt.% Reagents with a ratio amine: acetylene hydrocarbon 1-2: 1 in a solvent). The catalyst charge was 1 g.

The heating of the catalyst and / or the reaction medium to the reaction temperature during the process of Examples 4-10 was carried out after placing the static or flow reactors in the resonator of the experimental microwave installation with an operating frequency of 5.7 GHz and adjustable power in the range of 1-10 W. The selection of microwave power set the required process temperature. The process conditions in a flow reactor are presented in table 2.

Example 11 (comparative). Hydroamination was carried out according to example 9, except that the catalyst in the flow reactor was heated to the reaction temperature using an electric heating furnace.

The test results of the catalysts in examples 1-3 are shown in tables 1 and 2.

Table 1 The results of hydroamination of acetylene UV in the presence of Au-containing catalysts under conditions of microwave activation (heating) in a static reactor No. Cut-off example No. Rast-l (Wednesday) Reagents (mol. Rel.) Acet. / Cr (wt.%) T, ° C Reaction time, hour Acetylene Conversion,% Productivity, wt.% - acet / mmo l-Au four one Toluene aniline / octin-1 (1: 1) 3/1 one hundred 8 95.6 108 5 one Toluene aniline / FA (1: 1) 4/1 one hundred 6 90.3 134 6 one DMF morpholine / octin-1 (2: 1) 2,5 / 1 130 10 85.7 80 7 2 [BMIM] PF ₆ aniline / FA (2: 1) 1/1 150 6 98.5 183 8 3 styrene aniline / FA (2: 1) 3/1 130 10 75,4 210

table 2 The results of hydroamination of acetylene UV in the presence of Au-containing catalysts under conditions of microwave activation (heating) in a flow reactor No. Cut-off example No. Mortar (Wednesday) Reagents (mol. Rel.) T, ° C Mass speed, h ^-1 Acetylene Conversion,% Productivity, mmol-acet / mol-Au hour 9 one Toluene aniline / FA (2: 1) one hundred one 98.6 12 10 3 DMF aniline / FA (1: 1) 110 0.5 75,5 eleven eleven* one Toluene aniline / FA (2: 1) one hundred one 49.0 6 * - comparative example

Comparison of the conversion of acetylene hydrocarbons during the hydroamination reaction on the three-component Au / IL / MSM-41 catalysts proposed in the present invention with the proposed method using microwave activation and using ionic liquids (as a solvent or supported on a carrier), on the one hand, and known from literature Au / MCM-41 catalysts for hydroamination in the thermal regime of the reaction, on the other hand, shows that the proposed method using three-component catalysts and Microwave heating allows to achieve high conversion of the process with a significant reduction in reaction time. So, when carrying out the reaction in the microwave activation mode using octin-1 and aniline under other identical process conditions (temperature, reagent ratio), the time to achieve a conversion close to 100% was reduced from 22 hours (see prototype) to 8 hours (see example 4). In the case of hydroamination of phenylacetylene with aniline, ceteris paribus (see example 5), the productivity of the process for 6 hours per active metal gold in the catalyst (in the prototype is designated as TON in mmol-FA / mmol-Au) was 134, while in the prototype a value of 58 was obtained for 22 hours of reaction.

In addition, the value of the hourly productivity of the process (12 mmol-FA / mmol-Au hour) on the proposed in the present invention three-component Au / IL / MSM-41 catalyst in a flow reactor at 100 ° C (example No. 9) is comparable with the performance for 22 hours of operation (58 mmol-FA / mmol-Au) in a static reactor at the same temperature on an Au / MCM-41 catalyst according to the invention prototype without the addition of ionic liquid.

A comparison of the results of examples No. 9 and 11 (comparative) shows that the conversion of phenylacetylene and, accordingly, the productivity of the hydroamination process under microwave heating is 2 times higher than under traditional thermal heating.

It should be noted that in example No. 7, when using a low percentage catalyst (1% Au) according to example No. 2 and a solvent - ionic liquid [BMIM] PF ₆ , which are simultaneously able to accumulate the thermal energy of microwave radiation, a synergistic effect is observed, in which a high the value of the productivity of the hydroamination process (183 mmol FA per mmol of active gold) with a FA conversion of 98.5%.

The technical result of the invention is to reduce the hydroamination reaction time as a result of using the proposed three-component Au / IL / MSM-41 catalyst and, as a result, increasing the process productivity while maintaining a high degree of conversion of acetylene hydrocarbons. In addition, in all examples of the present invention, instead of thermal heating of the reactor, microwave radiation with very low power (up to 10 W) is used, which leads to lower energy costs. Additionally, example No. 8 illustrates the possibility of effective purification of styrene from phenylacetylene impurities, which is relevant in terms of purification of the monomer used in the production of polystyrene.

Claims (6)

1. The catalyst for the hydroamination of liquid acetylene hydrocarbons with an amine, comprising metal gold nanoparticles on a support, characterized in that it contains a mesoporous zeolite-like silicate MCM-41, modified with an ionic liquid, in the following ratio, wt.%:
Au 1-5 ionic liquid 5-20 carrier rest 2. The catalyst according to claim 1, characterized in that it contains 1-n-butyl-3-methylimidazolium hexafluorophosphate or 1-n-butyl-3-methylimidazolium tetrafluoroborate as an ionic liquid. 3. The method of hydroamination of liquid acetylene hydrocarbons with an amine using a gold-containing catalyst at an elevated temperature, characterized in that the catalyst according to claim 1 is used and the process is carried out under microwave heating of the catalyst in an organic solvent at a temperature of 100-150 ° C and a molar ratio of amine : acetylene hydrocarbon, equal to 1-2: 1. 4. The method according to claim 3, characterized in that as an organic solvent use toluene, styrene, dimethylformamide or an ionic liquid according to claim 2. 5. The method according to claim 3, characterized in that as an amine use aniline or morpholine. 6. The method according to claim 3, characterized in that the hydroamination process is carried out in a static reactor with a mass ratio of acetylene hydrocarbon: catalyst according to claim 1, equal to 1-4: 1, or in a flow reactor with a fixed catalyst bed according to claim 1 with mass feed rate of liquid raw materials in the range of 0.5-1 h ^-1 .