RU2790674C1 - Complex nickel hydrogenation catalyst - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: hydrogenation catalyst is described containing a nickel(II) compound, a reducing agent, and a modifying additive; anhydrous nickel(II) bis(acetylacetonate) is used as the initial nickel(II) compound, triethylaluminum is used as a reducing agent, and amines are used as a modifying additive with the following molar ratio of components: Ni(acac)₂/AlEt₃/modifier=1:5-10:0.125-2.

EFFECT: described catalyst has high productivity and activity, while the catalytic hydrogenation process can be carried out at room temperature and normal pressure.

1 cl, 5 tbl, 30 ex

Description

The present invention relates to methods for the development and production of a highly efficient complex nickel catalyst for the hydrogenation of alkenes by activating nickel nanoparticles.

The results of intensive studies of complex catalytic systems carried out in different countries of the world indicate that the active nanoparticles formed during the interaction of the initial components, depending on the conditions, are capable of activating both the _H2 molecule and the unsaturated bond of the olefin. However, despite the widespread industrial use of Ziegler catalysts for the oligomerization of α-olefins [Kaminsky W. (Ed.). Polyolefins: 50 years after Ziegler and Natta II: Polyolefins by Metallocenes and Other Single-Site Catalysts / W. Kaminsky (Ed.) - Springer: Verlag Berlin Heidelberg, 2013. - 371 rubles], the available literature data on complex hydrogenation catalysts are controversial character. First of all, there is a low reproducibility of the quantitative parameters of such systems, namely, activity (TOF), productivity (TON) and stability of work under the conditions of hydrogenation processes [Yu.Yu. Titova, dis. … Dr. chem. Sciences: 02.00.04. - Irkutsk, 2018. - 368 p.].

A known catalyst for the hydrogenation of unsaturated hydrocarbons based on transition metal compounds in various oxidation states, namely MeX _n (where n = 2-4, Me = Ti ⁴⁺ , VO ₄ ^3- , Ni ²⁺ , Cr ³⁺ , MoO ₂ ^{4 +} , Mn ³⁺ , Ru ³⁺ , Co ³⁺ , Fe ³⁺ , Pd ²⁺ ; X = acetylacetonate) in the presence of AlH _x R _3-x (where x = 0-3, R = alkyl, for example, iso- butyl, n-butyl) [Pat. United States Patent No. 3.113.986 dated 12/10/1963 C07C5/02; C07C5/03; C07C5/08]. Hydrogenation can be carried out in a wide range of temperatures (-50°С ÷ 250°С) and hydrogen pressures (1 ÷ 340 atm). Preferred temperature range 30÷50°C and pressure 1.4÷3.4 atm. The disadvantages of this catalyst include low values of activity and productivity of the described systems, for example, TON = 66 (mol octene-1)⋅(mol Ni) ^-1 , TOF = 0.27 min ^-1 .

A known catalyst for the hydrogenation of alkenes based on phosphine complexes of composition M(PR₃)₂X₂ (where M = Ni, Co, Pd; R = CH₃, C₂H₅, n-C₃H₇, n-C₄H₉, C₆H₅, OCH₃, C₆H₄-CH₃; X = Cl, Br, I) and lithium and sodium tetrahydroborates [Pat. United States Patent No. 3.270.087 of 8/30/1966 B01J31/24; C07C5/03]. The performance of the catalyst formed from (Ni[P(n-C₄H₉)₃]₂Cl₂) and NaBH₄ ([Ni]/[NaNH₄] = 10:1), in the hydrogenation of 1-octene at a hydrogen pressure of 2 atm and a temperature of 50°C is 18.7 (mol octane) (mol Ni)^-1. The average activity calculated for the entire duration of the experiment does not exceed 0.015 (mol substrate) (mol Ni min)^-1. During the hydrogenation of 1-hexene in the presence of the catalytic system Ni[P(n-C₄H₉)₃]₂Cl₂)-NaBH₄ ([Ni]/[NaBH₄] = 1:10) TON of the catalyst was 8.5 (mol hexene-1) (mol Ni)^-1; and the TOF of the catalyst is 5.9 10^-3 (mol substrate) (mol Ni min)^-1. The disadvantage of the considered nickel catalyst is the low catalytic activity and productivity.

Known complex catalyst for the hydrogenation of unsaturated hydrocarbons based on MX ₂ L ₂ -AlH(Ot-Bu) ₂ (M = Co, Ni, Ti, Cr, V, Mn, Fe, Cu, Zr, Mo, Ru, Rh, Pd, Ag , W, Re, Os, Ir and Pt, preferably Co and Ti, X=Cl or Br, L=P(C ₆ H ₁₁ ) ₃ , pyridine, PO(C ₆ H ₅ ) ₃ ), CoBr[PO(C ₆ H ₅ ) ₃ ] ₃ -AlH(Ot-Bu) ₂ , CoBr ₂ -AlH(NC ₄ H ₉ ) ₂ , as well as Zn(acac) ₂ -AlH ₂ (Ot-Bu) at a molar ratio of components 1/1 ÷1.20 [Pat. France Patent No. 1.264.254 dated 12.02.1972 C07B1/0; B01J11/84]. Catalytic hydrogenation was carried out mainly at T=20-30°C and 0.12 atm. The highest of the described activities corresponds to 77 min ^-1 for the system based on CoBr ₂ [PO(phenyl) ₃ ] ₂ -AlH(Ot-Bu) ₂ . At the same time, the authors note that, in addition to all other parameters, the catalytic activity of the described systems is strongly affected by the presence of impurities such as water or alcohols in solvents, as well as traces of water on the walls of the reaction vessels. This fact can certainly be attributed to a significant drawback of these catalysts, given that the authors do not provide accurate methods for the preparation of the starting components of catalytic systems and solvents.

Known complex catalyst for the hydrogenation of unsaturated hydrocarbons (alkenes or alkynes) based on compounds of di- and trivalent transition metals, namely MeX₂ and MeX₃ (where Me = Fe, Co, Ni, Ru, Rh, Pd, Ir, Pt, Re, Os, V, Cr, Mn, Cu, Zr, Mo, Ag, W; X = Cl, Br, I, acetylacetonate, naphthenate, oleate, stearate, 2-ethylhexanoate and acetate), TiR₂X₂ (X = halides, alkoxides, thio- and carboxylates; R - cyclopentadienyl (Cp), CH₃, WITH₂H₅, iso-C₄H₉, tert-C₄H₉, n-C₄H₉, iso-C₅H_eleven, C₇H₁₅, C₁₈H₃₇, C₆H₅, C₇H₇), as well as AlH_nX_3-n (where n = 1 or 2, X = OR, NR₂, NHR or SR, R = Alk, Ar; the composition of a linear or cyclic hydrocarbon radical may include heteroatoms: oxygen, nitrogen, sulfur) or M[AlH_mX'_4th]_p (where m = 1-3; X' = OR, NR₂, NHR or SR, R = Al; the composition of a linear or cyclic hydrocarbon radical may include heteroatoms: oxygen, nitrogen, sulfur; M = metal IA, IIA groups) [Pat. United States Patent No. 3.784.481 A dated 08/01/1974 B01J31 / 14; B01J31/18; B01J31/22; B01J31/30; (IPC1-7): C07C5/02]. Catalytic hydrogenation was carried out at -50÷250°С and Р_H2=0.01÷296 atm. TON of the nickel catalyst formed in the Ni(C₇H₁₅COO)₂-Na[AlH₂(OCH₂CH₂OCH₃)₂] ([Ni]/[Al]=1:2) in the presence of pyridine ([Ni]/[pyridine]=1:2) in the hydrogenation of hexine-1 at T= 90°C and a hydrogen pressure of 29.6 atm does not exceed 73.6 (mol hexine) (mol Ni)^-1. The disadvantages of this nickel catalyst include its low productivity (TON = 73.6 (mol hexine) (mol Ni)^-1) when carrying out the hydrogenation process under fairly severe conditions and, therefore, the need to carry out the hydrogenation process in an autoclave.

A known catalyst for the hydrogenation of cyclohexane, decene-1 and dodecene-1 based on NiX ₂ complexes, where X is acetylacetonate (ACAS), 3,5-diisopropyl salicylate (dips), stearate (stearate), phenylhydroxomat (bzh)), in combination with AlEt ₃ , Al(iso-Bu) ₃ or Li(n-Bu) [Reguli J., Stasko A. // Chem. Pap. - 1987. - V. 41, No. 3. - P. 299-310.]. Catalytic hydrogenation was carried out under mild conditions at 30°С and _РН2 = 120 kPa (1.2 atm)). The maximum catalytic activity for the system based on Ni(acac) ₂ -AlEt ₃ in the hydrogenation of cyclohexene was 21 min ^-1 . The disadvantages of this complex hydrogenation catalyst include its low speed and low stability and, as a result, the lack of data on its performance.

The closest known solution to a similar problem in terms of technical essence and the achieved effect is a nickel catalyst for the hydrogenation of alkenes and a method for its preparation, described in patent No. 31/12; C07C 5/02). Nickel hydrogenation catalyst is obtained by reduction of nickel(II) bis(acetylacetonate) crystalline hydrate, triethylaluminum as a reducing agent, and ketones and esters as a modifying additive in the following ratio of components: Ni(acac)₂ / N₂ABOUT / AlEt₃ / modifier = 1 : 0.5-3.0 : 1-10 : 1-100. The efficiency of the catalyst depends on the content of water of crystallization in the initial nickel(II) compound, the ratio of the components of the catalytic system, the nature and concentration of the modifying additive - ketones (acetylacetone acacH, acetophenone C₈H₈Oh, acetone CH₃C(O)CH₃) or ethers (diethyl ether C₂H₅OS₂H₅). Maximum throughput (TON) was achieved under the following shaping conditions: [Ni(acac)₂] / [H₂O] / [AlEt₃] = 1 : 0.5 : 5 and the ratio [modifier] : [AlEt₃] for the most effective promoter, acetone, equal to 2.5 ([acetone] /[AlEt₃] = 2.5) and amounted to 3045 (mol styrene)⋅(mol Ni)^-1. At the same time, the activity in this case was not high, namely 38 mol H₂⋅(mol Ni⋅min)^-1. The main disadvantage of this nickel catalyst is that when high activity values are reached, the productivity values are low and vice versa.

The present invention is based on the solution of the problem of obtaining a nickel-containing hydrogenation catalyst, which would have both high productivity and high activity, while being able to carry out the catalytic hydrogenation process under mild conditions (at room temperature and normal (atmospheric) pressure).

The task is achieved by the fact that for the formation of an effective in hydrogenation under mild conditions (temperature 30 ° C (303 K) and hydrogen pressure 1 excess atm.) Nickel catalyst as the initial nickel(II) compound using anhydrous Ni(acac) ₂ , as a reducing agent - triethylaluminum, and as a modifier - amines (aliphatic and aromatic) at the following molar ratio of reagents: [Ni(acac) ₂ ] / [AlEt ₃ ] / [modifier] = 1 : 5-10 : 0.125-2. The efficiency of the catalyst depends on the ratio of the components of the catalytic system, the nature and concentration of the modifying additive. The modifying additive is introduced after the addition of triethylaluminum to a solution of Ni(acac) ₂ in an anhydrous organic solvent (benzene) after the introduction of the substrate.

The applicant has not identified sources containing information on technical solutions identical to the present invention, which allows us to conclude that it meets the criterion of "novelty".

A distinctive feature of the present invention is the use of Ni(acac) ₂ as the initial nickel(II) compound, triethylaluminum as a reducing agent, and amines (aliphatic and aromatic amines) as a modifying additive.

The applicant did not find any sources of information containing information about the impact of the claimed distinctive features on the technical result achieved as a result of their implementation. This, according to the applicant, testifies to the compliance of this technical solution with the criterion of "inventive step".

The proposed approach for the formation of an efficient nickel catalyst for the hydrogenation of unsaturated compounds (alkenes) is as follows:

To a solution of nickel bis(acetylacetonate) Ni(acac) ₂ in dehydrated benzene (water content according to Fischer does not exceed 1 mmol/l), placed in a temperature-controlled duck-type vessel, at room temperature in a stream of hydrogen, an alkene and a solution of AlEt ₃ are successively added in octane. After adding AlEt ₃ the color of the solution changes from green to bright orange. The resulting reaction mixture is stirred at a temperature of 30°C (303 K) for 5-20 min at a hydrogen pressure of 2 atm. After 5-20 min from the start of mixing the components, an aliquot of the modifying additive is introduced into the reaction mixture.

The optimal conditions for the formation of a nickel catalyst are as follows: [Ni(acac) ₂ ] / [AlEt ₃ ] = 5-10. The ratio [modifier] : [AlEt ₃ ] depends on the nature of the modifier (Table 2). For the most efficient promoter, tributylamine, it is 0.5 ([N(n-Bu) ₃ ]/[ _AlEt3 ] = 0.5) (Table 4).

The quantitative characteristics of the nickel catalyst obtained in this way in the hydrogenation of styrene at a temperature of 30°C (303 K) and a hydrogen pressure of 2 atm reach the following values:

1) activity ~60 min ^-1 and productivity not less than (the phrase "not less" was used because the technical capabilities of the reaction vessel of the "duck" type did not allow hydrogenation of more than 39 ml of styrene) 3400 (mol styrene) (mol Ni) ^{- 1} when using triethylamine as a modifier (Table 3);

2) activity ~85 min ^-1 and productivity not less than 3400 (mole of styrene)∙(mol Ni) ^-1 when diethylamine is used as a modifier (Table 4);

3) activity 88.5 min ^-1 and productivity not less than 3400 (mol styrene)·(mol Ni) ^-1 when using tributylamine as a modifier (Table 5).

The advantage of this nickel catalyst is increased stability, which manifests itself in higher productivity and activity in the hydrogenation of alkenes under mild conditions - at a temperature of 30°C (303 K) and a hydrogen pressure of 1 wt. atm (2 atm).

Example 1-4: To a solution of 0.0256 g (1.0⋅10^-4 mol) sublimated Ni(acac)₂1 ml of styrene (8.7⋅10^-3 mol), 2 ml AlEt solution₃ (1.0⋅10^-4 mol) in octane and the reaction mixture is stirred for 20 min at 30°C and a hydrogen pressure of 1 excess atmosphere. The progress of the process is controlled by the drop in hydrogen pressure on the manometer and analysis of samples by GLC methods (chromatograph Khromatek-Kristall 5000.2 (Khromatek, Russia), equipped with a flame ionization detector, using an SGE BPX5 capillary column (length 30 m, diameter 0.53 mm), and mass spectrometry (mass spectrometer GCMS-QP-2010, Shimadzu, Japan)). Styrene hydrogenation does not occur (Table 1).

Example 5-12: To a solution of 0.0256 g (1.0⋅10^-4 mol) Ni(acac)₂1 ml of styrene (8.7⋅10^-3 mol), 2 ml AlEt solution₃ (1.0⋅10^-3 mol) in octane and stir the reaction mixture for 20 min at 30°C and a hydrogen pressure of 1 excess atmosphere. The progress of the process is controlled by the drop in hydrogen pressure on the pressure gauge and analysis of samples by GLC methods (chromatograph Khromatek-Kristall 5000.2 (Khromatek, Russia), equipped with a flame ionization detector, using an SGE BPX5 capillary column (length 30 m, diameter 0.53 mm), and mass spectrometry (mass spectrometer GCMS-QP-2010, Shimadzu, Japan)). Hydrogenation of styrene does not occur. To the resulting transparent bright orange "solution" is added a modifying additive - amine, in the ratio [amine] / [AlEt₃] = 1. After the introduction of the modifier, the nickel catalyst is active in the hydrogenation of styrene under mild conditions and is characterized by a high turnover number and turnover purity (Table 2).

Example 13-18: These examples illustrate the influence of the concentration of the modifier - triethylamine on the activity and productivity of the Ni(acac) ₂ + 5AlEt ₃ system in the hydrogenation of styrene (Table 3). The procedure for conducting experiments is similar to example 5.

Example 19-24: These examples illustrate the effect of diethylamine modifier concentration on the activity and productivity of the Ni(acac) ₂ + 5AlEt ₃ system in styrene hydrogenation (Table 4). The procedure for conducting experiments is similar to example 5.

Example 26-30: These examples illustrate the effect of tributylamine modifier concentration on the activity and productivity of the Ni(acac) ₂ + 5AlEt ₃ system in styrene hydrogenation (Table 4). The procedure for conducting experiments is similar to example 5.

As can be seen from the description and tables, the proposed method makes it possible to obtain nickel hydrogenation catalysts with both high activity and high productivity in the hydrogenation of alkenes (styrene).

Of course, the invention is in no way limited to the embodiments described and illustrated, which have been presented by way of example only.

Table 1 - Influence of the AlEt ₃ /Ni ratio on the catalytic properties of Ni(acac) ₂ + nAlEt ₃ in styrene hydrogenation experience number 1 2 3 4 [AlEt ₃ ]/[Ni(acac) ₂ ] 1 2 5 10 TON performance,
(mol styrene) (mol Ni) ^-1 87 0 0 0 TOF activity, min ^-1 1.6 0 0 0

Note: C _Ni = 5.6 mmol/l, [substrate]/Ni = 87, solvent - benzene-octane (V _toluene / V _octane = 15:2), solvent volume = 17 ml; T \u003d 30 ° C, P _H2 \u003d 2 atm.

Table 2 - Influence of the nature of the modifier - amine ([amine]/[AlEt ₃ ]=1) on the activity and productivity of the Ni(acac) ₂ + 5AlEt ₃ system in styrene hydrogenation experience number Amine Productivity TON, (mole of styrene)
(mol Ni) ^-1 TOF activity,
(mol H ₂ ) (mol Ni⋅min) ^-1 5 HNEt ₂ 2484 40 6 NET ₃ 2375 46 7 H ₂ N(n-Bu) 609 40 8 HN(n-Bu) ₂ 1566 57 9 N(n-Bu) ₃ 2088 83 10 _H2NPh 783 34 eleven HNPh ₂ 235 4 12 N(CH ₂ Ph) ₃ 87 0.4

Note: C _Ni = 5.6 mmol/l, [substrate]/Ni = 87, solvent - benzene-octane (V _toluene / V _octane = 15 : 2), solvent volume = 17 ml; T \u003d 30 ° C, P _H2 \u003d 2 atm.

Table 3 - Influence of the concentration of the modifier - triethylamine on the activity and productivity of the Ni(acac) ₂ + 5AlEt ₃ system in styrene hydrogenation experience number 13 14 15 16 17 18 [amine]/[AlEt ₃ ] 0.125 0.25 0.5 0.75 1.0 2.0 TON performance,
(mol styrene) (mol Ni) ^-1 1240 2140 >3400 2436 2375 1653 TOF activity, min ^-1 32.2 45 60.0 58.0 47.0 43.8

Note: C _Ni = 5.6 mmol/l, [substrate]/Ni = 87, solvent - benzene-octane (V _toluene / V _octane = 15 : 2), solvent volume = 17 ml; T \u003d 30 ° C, P _H2 \u003d 2 atm.

Table 4 - Effect of the concentration of the modifier - diethylamine on the activity and productivity of the Ni(acac) ₂ + 5AlEt ₃ system in styrene hydrogenation experience number 19 20 21 22 23 24 [amine]/[AlEt ₃ ] 0.125 0.25 0.5 0.75 1.0 2.0 TON performance,
(mol styrene) (mol Ni) ^-1 1566 >3400 2697 2610 2523 2175 TOF activity, min ^-1 42.5 84.5 74.4 47.7 42.9 40.4

Note: C _Ni = 5.6 mmol/l, [substrate]/Ni = 87, solvent - benzene-octane (V _toluene / V _octane = 15 : 2), solvent volume = 17 ml; T \u003d 30 ° C, P _H2 \u003d 2 atm.

Table 5 - Influence of the concentration of the modifier - tributylamine on the activity and productivity of the Ni(acac) ₂ + 5AlEt ₃ system in styrene hydrogenation experience number 25 26 27 28 28 thirty [amine]/[AlEt ₃ ] 0.125 0.25 0.5 0.75 1.0 2.0 TON performance,
(mol styrene) (mol Ni) ^-1 1305 2088 >3400 2723 2588 2088 TOF activity, min ^-1 55.9 85.8 88.5 84 85 85

Note: C _Ni = 5.6 mmol/l, [substrate]/Ni = 87, solvent - benzene-octane (V _toluene / V _octane = 15 : 2), solvent volume = 17 ml; T \u003d 30 ° C, P _H2 \u003d 2 atm.

Claims (1)

Hydrogenation catalyst containing a nickel(II) compound, a reducing agent and a modifying additive, characterized in that anhydrous nickel(II) bis(acetylacetonate) is used as the initial nickel(II) compound, triethylaluminum is used as a reducing agent, and triethylaluminum is used as a modifying additive. amines in the following molar ratio of components: Ni(acac) ₂ /AlEt ₃ / modifier = 1:5-10:0.125-2.