METHOD FOR OXIDATIVE CLEAVAGE OF OLEFINS USING A HALOOXODIPEROXOMETALLATE AS A CATALYST

Abstract

The present invention relates to a method for oxidative cleavage of a substrate consisting of at least one functionalised or non-functionalised linear olefin, in particular a mono- or polyunsaturated aliphatic carboxylic acid, or one of the esters thereof, or at least one non-functionalised cyclic olefin, using hydrogen peroxide, in the presence of a metal catalyst which consists of at least one onium halooxodiperoxometallate. It also relates to a novel catalyst consisting of a specific onium halooxodiperoxometallate which can be used, in particular, in said method.

Claims

1-17. (canceled)

18. A process for the oxidative cleavage of a substrate consisting of at least one functionalized or non-functionalized linear olefin or of at least one non-functionalized cyclic olefin, comprising converting a carbon-carbon double bond of the substrate into two separate oxidized functional groups chosen from aldehydes, ketones and carboxylic acids, using hydrogen peroxide, in the presence of a metal catalyst, characterized in that the catalyst is formed of at least one onium halooxodiperoxometallate.

19. The process of claim 18, characterized in that the onium is selected from the group consisting of a tetraalkylammonium, a tetraalkylphosphonium and an alkylpyridinium, the alkyl groups of which independently include from 1 to 20 carbon atoms, benzethonium and triphenylphosphoranylidene.

20. The process of claim 18, characterized in that the halooxodiperoxometallate is a compound of formula (I): ##STR00005## where: M is a metal selected from the group consisting of W and Mo, X is a halogen atom, L denotes a neutral ligand having at least one non-bonding lone pair.

21. The process of claim 20, characterized in that L is selected from the group consisting of water, amines, ethers and phosphines.

22. The process of claim 21, characterized in that L is water.

23. The process of claim 20, characterized in that the halooxodiperoxometallate is selected from the group consisting of chlorooxodiperoxotungstate, fluorooxodiperoxotungstate, bromooxodiperoxotungstate and iodooxodiperoxotungstate.

24. The process of claim 23, characterized in that the halooxodiperoxometallate is chlorooxodiperoxometallate.

25. The process of claim 18, characterized in that the catalyst is employed in an amount ranging from 0.1 molar % to 10 molar %, with respect to the molar amount of double bonds in the substrate.

26. The process of claim 25, characterized in that the catalyst is employed in an amount ranging from 2 molar % to 6 molar %, with respect to the molar amount of double bonds in the substrate.

27. The process of claim 18, characterized in that the hydrogen peroxide is employed in an amount ranging from 4 to 20 molar equivalents, with respect to the molar amount of double bonds in the substrate.

28. The process of claim 18, characterized in that the substrate consists of at least one mono- or polyunsaturated aliphatic carboxylic acid or one of its esters, and in that it is employed in the preparation of at least one dicarboxylic acid or one of its esters, respectively, and optionally of at least one monocarboxylic acid.

29. The process of claim 28, characterized in that the mono- or polyunsaturated aliphatic carboxylic acid or one of its esters is selected from the group consisting of: oleic acid, palmitoleic acid, erucic acid, linoleic acid, α-linolenic acid, their mixtures and/or one of their esters.

30. The process of claim 29, characterized in that the mono- or polyunsaturated aliphatic carboxylic acid or one of its esters is oleic acid or one of its esters.

31. The process of claim 28, characterized in that the dicarboxylic acid is selected from the group consisting of azelaic acid, adipic acid, succinic acid, sebacic acid, 1,7-heptanedioic acid, 1,8-octanedioic acid, 1,11-undecanedioic acid, 1,12-dodecanedioic acid, brassylic acid, 1,14-tetradecanedioic acid, 1,15-pentadecanedioic acid and thapsic acid.

32. The process of claim 31, characterized in that the dicarboxylic acid is azelaic acid.

33. The process of claim 28, characterized in that the method comprises: mixing the catalyst, previously formed in situ or isolated, with the substrate, optionally brought beforehand to a temperature of 20 to 120° C., and with hydrogen peroxide, bringing the mixture to a temperature of from 20 to 120° C. for a period of time ranging from 2 to 24 hours, with stirring, and recovering the dicarboxylic acid or its ester thus formed, and optionally the monocarboxylic acid or its ester obtained as coproduct.

34. The process of claim 18, characterized in that the substrate consists of at least one non-functionalized cyclic olefin.

35. The process of claim 34, characterized in that the substrate is selected from the group consisting of: cyclohexene, cycloheptene, cyclooctene, cyclononene, cyclodecene, cycloundecene, cyclododecene, dicyclopentadiene, norbornene and norbornadiene.

36. A catalyst of formula (II): ##STR00006## in which: M is a metal chosen from W and Mo, X is a halogen atom, L denotes a neutral ligand having at least one non-bonding lone pair. Q.sup.+ denotes an onium cation of formula N.sup.+(R.sub.1R.sub.2R.sub.3R.sub.4), where: R.sub.1 denotes a linear or branched C.sub.6-C.sub.20 alkyl group, R.sub.2 and R.sub.3 each independently denote a linear or branched C.sub.1-C.sub.4 alkyl group and R.sub.4 denotes a linear or branched, C.sub.1-C.sub.4 alkyl group or an aryl group, or else R.sub.1 denotes a linear or branched C.sub.4-C.sub.14 alkyl group and R.sub.2, R.sub.3 and R.sub.4 form, with the nitrogen atom, a pyridinium group.

37. The catalyst of claim 36, characterized in that R.sub.1 denotes a linear or branched C.sub.12-C.sub.18 alkyl group, R.sub.2 and R.sub.3 each denote a methyl group and R.sub.4 denotes a methyl group or an aryl group.

38. The catalyst of claim 36, characterized in that the halogen is chlorine or fluorine.

39. The catalyst of claim 36, characterized in that the catalyst is dodecyltrimethylammonium chlorooxodiperoxotungstate.

40. The catalyst of claim 36, characterized in that L is H.sub.2O.

41. The catalyst of claim 36, characterized in that when R.sub.1, R.sub.2 and/or R.sub.3 denotes an alkyl group, this alkyl group is linear.

42. A method for the oxidative cleavage of compounds selected from the group consisting of mono- or polyunsaturated aliphatic carboxylic acids and their esters, comprising contacting said compounds with hydrogen peroxide in the presence of the catalyst of claim 36.

Description

FIGURES

[0086] FIG. 1 represents the molecular structure of the compound described in example 2, obtained by XRD and represented with 50% probability ellipsoids.

EXAMPLES

[0087] A better understanding of the invention will be obtained in the light of the following examples, which are given purely by way of illustration and do not have the aim of limiting the scope of the invention, defined by the appended claims.

[0088] Materials and Methods

[0089] The reactants originate from ordinary commercial suppliers (Sigma-Aldrich-Merck, Acros, Alfa-Aesar, Fisher) and were used without prior purification.

[0090] All the reactions were carried out in air, at atmospheric pressure.

[0091] The GC-MS analyses were carried out with a Shimadzu QP2010SE instrument, using H.sub.2 as carrier gas, with a Zebron Fast GC (Phenomenex) (20 m×0.18 mm×0.18 m) column. The GC-MS quantification was carried out using octanoic acid as internal standard. The concentrations of azelaic acid, pelargonic acid and oleic acid were calculated using a calibration curve (R.sup.2>0.99 in the three cases).

[0092] The proton Nuclear Magnetic Resonance (NMR) spectra were recorded on an Avance 400 NMR spectrometer at 400.1 MHz (Bruker) at 25° C. The chemical shifts are expressed in ppm (parts per million) with respect to the signal of the residual non-deuterated solvent. The multiplicity of the signals is described as follows: singlet (s), doublet (d), triplet (t) and multiplet (m).

Example 1: General Process for the Preparation and Characterization of the Catalysts

[0093] 1A) Preparation by Precipitation (Case of the Water-Insoluble Ammoniums, Such as Dodecyltrimethylammonium Chloride and Hexadecylpyridinium Chloride):

[0094] Na.sub.2WO.sub.4.2H.sub.2O (6.93 mmol, 1.00 eq.) is introduced into a 50 ml round-bottomed flask and then 5 ml of distilled water are added in order to dissolve Na.sub.2WO.sub.4.2H.sub.2O. An H.sub.2SO.sub.4 solution (2M, 5 mmol; 0.72 eq.) is subsequently added to this solution, immediately followed by the addition of aqueous hydrogen peroxide solution (30 w/v %; 37.48 mmol; 5.4 eq.). The solution turns yellow and then virtually colorless. The pH of the latter is located between 0.9 and 1.1; if not, it can be adjusted with a few additional drops of the H.sub.2SO.sub.4 solution. The alkylammonium chloride, dissolved beforehand in 5 ml of distilled water, is subsequently added dropwise (7.28 mmol; 1.05 eq.). The medium is subsequently stirred at 20° C. for 30 minutes, then placed under cold conditions (4° C.) overnight. The precipitate formed is filtered off and then rinsed with H.sub.2O (4×50 ml) and then with ethanol cooled to 0° C. (25 ml). The product is subsequently predried on a rotary evaporator and then dried overnight under vacuum in the presence of P.sub.2O.sub.5.

[0095] 1B) Preparation by Extraction (Case of all the Other Ammoniums and Phosphoniums, Also Applicable to Those Prepared by Precipitation):

[0096] Na.sub.2WO.sub.4.2H.sub.2O (6.93 mmol; 1.0 eq.) is introduced into a 50 ml round-bottomed flask and then 5 ml of distilled water are added in order to dissolve Na.sub.2WO.sub.4.2H.sub.2O. An H.sub.2SO.sub.4 solution (2M, 5 mmol; 0.72 eq.) is subsequently added to this solution, immediately followed by the addition of aqueous hydrogen peroxide solution (30 w/v %; 37.48 mmol; 5.4 eq.). The solution turns yellow and then virtually colorless. The pH of the latter is located between 0.9 and 1.1; if not, it can be adjusted with a few additional drops of the H.sub.2SO.sub.4 solution. The alkylammonium halide, in solution in 10 ml of dichloromethane, is subsequently added to the medium (7.28 mmol; 1.05 eq.). The solution is subsequently stirred vigorously at 20° C. for 1 h 30. The phases are subsequently separated and the aqueous phase is extracted with 15 ml of dichloromethane. The organic phase is dried with anhydrous sodium sulfate and then evaporated on a rotary evaporator. The solid obtained is dried under vacuum overnight.

[0097] The yields obtained on conclusion of the above processes are collated in the following table.

TABLE-US-00003 Isolated Halooxodiperoxometallate catalyst yield Dodecyltrimethylammonium chlorooxodiperoxotungstate 85% Trioctylmethylammonium chlorooxodiperoxotungstate 66% Tetradecyltrimethylammonium chlorooxodiperoxotungstate 34% Octadecyltrimethylammonium chlorooxodiperoxotungstate 86% Dimethyldioctadecylammonium chlorooxodiperoxotungstate 47% Tetrabutylammonium chlorooxodiperoxotungstate 62% Benzyldimethyldodecylammonium chlorooxodiperoxotungstate 36% Benzyldimethyltetradecylammonium chlorooxodiperoxotungstate 60% Benzyldimethylhexadecylammonium 52% chlorooxodiperoxotungstate Benzyldimethylstearylammonium chlorooxodiperoxotungstate 79% Dodecylpyridinium chlorooxodiperoxotungstate 58% Hexadecylpyridinium chlorooxodiperoxotungstate 75% Benzethonium chlorooxodiperoxotungstate 58% Tetradecyltrihexylphosphonium chlorooxodiperoxotungstate 62% Bis(triphenylphosphoranylidene)ammonium 68% chlorooxodiperoxotungstate Tetrabutylammonium fluorooxodiperoxotungstate

Example 2: Preparation and Characterization of Dodecyltrimethylammonium Chlorooxodiperoxotungstate

[0098] ##STR00004##

[0099] Na.sub.2WO.sub.4.2H.sub.2O (6.93 mmol, 1.00 eq.) is introduced into a 50 ml round-bottomed flask and then 5 ml of distilled water are added in order to dissolve Na.sub.2WO.sub.4.2H.sub.2O. An H.sub.2SO.sub.4 solution (2M, 5 mmol; 0.72 eq.) is subsequently added to this solution, immediately followed by the addition of aqueous hydrogen peroxide solution (30 w/v %; 37.48 mmol; 5.4 eq.). The solution turns yellow and then virtually colorless. The pH of the latter is located between 0.9 and 1.1; if not, it can be adjusted with a few additional drops of the H.sub.2SO.sub.4 solution.

[0100] Dodecyltrimethylammonium chloride, dissolved beforehand in 5 ml of distilled water, is subsequently added dropwise (7.28 mmol; 1.05 eq.). A white precipitate forms, then redissolves. The medium is subsequently stirred at 20° C. for 30 minutes, then placed under cold conditions (4° C.) overnight. The precipitate formed is filtered off and then rinsed with H.sub.2O (4×50 ml) and then with ethanol cooled to 0° C. (25 ml). The product is subsequently predried on a rotary evaporator and then dried overnight under vacuum in the presence of P.sub.2O.sub.5.

[0101] Dodecyltrimethylammonium chlorooxodiperoxotungstate is obtained in the form of a white powder with a molar yield of 85%.

[0102] .sup.1H NMR (CDCl.sub.3, 400 MHz) δ: 0.75 (m, 3H); 1.06-1.30 (m, 18H); 1.60 (m, 2H); 3.06-3.20 (s, 9H); 3.81 (m, 2H); .sup.13C NMR (101 MHz, CDCl.sub.3) δ: 66.8, 52.9, 31.8, 29.5, 29.4, 29.2, 26.2, 23.0, 22.5, 13.9; IR ν.sub.max 2915, 2850, 1469, 947, 835, 775, 720, 619, 572, 547, 486, 419.

[0103] Single-Crystal X-Ray Diffraction:

[0104] The measurements were carried out on a D8 VENTURE Bruker AXS diffractometer equipped with a PHOTON 100 (CMOS) detector, with Mo-Kα radiation (λ=0.71073 Å, multilayer monochromator), T=150(2) K; monoclinic crystal P 2.sub.1/c (IT. #14), a=18.8525(16), b=7.3078(7), c=15.3995(14) Å, β=97.340(4)°, V=2104.2(3) Å.sup.3. Z=4, d=1.723 g.Math.cm.sup.−3, μ=5.643 mm.sup.−1. The structure was solved by a dual space algorithm using the SHELXT program [G. M. Sheldrick, Acta Cryst., A71 (2015), 3-8], then refined by full matrix least squares methods based on F2 (SHELXL) [Sheldrick G. M., Acta Cryst., C71 (2015), 3-8]. All the atoms other than hydrogen were refined with anisotropic atomic shift parameters. A final refinement on F2 with 4810 unique intensities and 227 parameters converged to ωR(F2)=0.0496 (R(F)=0.0218) for 4125 reflections observed with I>2σ(I).

[0105] The structure obtained is illustrated in the appended FIGURE.

Example 3: Oxidative Cleavage of Oleic Acid

[0106] A 250 ml single-necked round-bottomed flask equipped with a 20×10 mm magnetic bar is charged with dodecyltrimethylammonium chloroperoxotungstate catalyst (700 mg, 1.28 mmol, 0.040 eq.) and then with oleic acid (90% purity) (10.0 g, 31.86 mmol, 1.0 eq.). The mixture is stirred at 300 revolutions/min at 22° C. for 5 min, forming a homogeneous white liquid phase. 60% (w/V) aqueous hydrogen peroxide solution (10.84 ml, 191.16 mmol, 6.0 eq.) is then added dropwise to this mixture at 22° C. with stirring over 5 min. The round-bottomed flask is subsequently equipped with a reflux condenser and the reaction mixture is brought to reflux by contact with a metal heating block (DrySyn block, Asynt) preheated to 90° C., with stirring at 1000 revolutions/min, for 5 h. During the reaction, the reaction medium remains two-phase, with a white lower phase and a colorless upper phase. On completion of the reaction, the medium is allowed to cool to 22° C. After cooling, a white solid appears at the bottom of the round-bottomed flask.

[0107] A GC-MS analysis of the medium is carried out after derivatization with trimethylsulfonium hydroxide (0.2 mol/l in methanol), according to a procedure described in Journal of Chromatography A, 2004, 1047, 111-116. The molar yields are then calculated with the help of a calibration curve, using octanoic acid as internal standard: azelaic acid 98%, pelargonic acid 74%.

[0108] The azelaic acid can be isolated by virtue of the following procedure: on completion of the reaction, 25 ml of deionized water are added to the round-bottomed reaction flask and then the mixture is heated to 90° C., with stirring at 300 revolutions/min. After heating for 10 min, the white solid dissolves completely, thus giving an off white solution. 20 ml of heptane are then added to the mixture and stirring is continued at 90° C. for 10 min. The heating and the stirring are subsequently stopped and the medium is then allowed to cool to 22° C. After 3 h, a white solid appears at the bottom of the round-bottomed flask, the upper phase being colorless. This mixture is then filtered on a Whatman glass microfiber disc (4.25 cm in diameter, reference 1820042) and rinsed with 3×75 ml of heptane. The white solid, consisting of azelaic acid, is collected and dried under reduced pressure in a desiccator, in the presence of P.sub.2O.sub.5. A weight of 6.44 g is obtained. The filtrate can be evaporated under reduced pressure, to give pelargonic acid in the form of a colorless oil.

[0109] The purity of the azelaic acid obtained is calculated by GC-MS analysis after derivatization with N,O-bis(trimethylsilyl)trifluoroacetamide with 1% of trimethylchlorosilane: 50 mg of azelaic acid are dissolved in 1 ml of THF, then 10 μl of this solution are introduced into a GC vial, followed by the addition of 100 μl of anhydrous pyridine and then 100 μl of N,O-bis(trimethylsilyl)trifluoroacetamide with 1% of trimethylchlorosilane. The mixture is heated and stirred in the GC vial at 40° C. for 1 h, then diluted with 600 μl of THF and injected in GC-MS. After GC-MS analysis, a purity of 91% is determined for the azelaic acid, the remainder consisting of traces of pelargonic acid (7%) and of C.sub.4 impurities (2%).

[0110] Taking into account the calculated purities and the weight of azelaic acid collected, the corrected isolated molar yield of azelaic acid is 97%.

[0111] By following the same protocol as in example 2 but with the other catalysts, the following yields are obtained:

TABLE-US-00004 Azelaic Pelargonic acid yield acid yield Catalyst (%) (%) [WO(O.sub.2).sub.2Cl•H.sub.2O][tetradecyltrimethylammonium] 78% 72% [WO(O.sub.2).sub.2Cl•H.sub.2O][octadecyltrimethylammonium] 69% 67% [WO(O.sub.2).sub.2Cl•H.sub.2O][trioctylmethylammonium] 39% 38% [WO(O.sub.2).sub.2Cl•H.sub.2O][dimethyldioctadecylammonium] 39% 38% [WO(O.sub.2).sub.2Cl•H.sub.2O][benzyldimethyldodecylammonium] 71% 68% [WO(O.sub.2).sub.2Cl•H.sub.2O][benzyldimethyltetradecylammonium] 68% 68% [WO(O.sub.2).sub.2Cl•H.sub.2O][benzyldimethylhexadecylammonium] 71% 66% [WO(O.sub.2).sub.2Cl•H.sub.2O][benzyldimethylstearylammonium] 68% 69% [WO(O.sub.2).sub.2Cl•H.sub.2O][dodecylpyridinium] 62% 59% [WO(O.sub.2).sub.2Cl•H.sub.2O][hexadecylpyridinium] 70% 66% [WO(O.sub.2).sub.2Cl•H.sub.2O][benzethonium] 64% 62% [WO(O.sub.2).sub.2Cl•H.sub.2O][tetradecyltrihexylphosphonium] 39% 40% [WO(O.sub.2).sub.2Cl•H.sub.2O][bis(triphenylphosphoranylidene)ammonium] 55% 54% [WO(O.sub.2).sub.2Cl•H.sub.2O][tetrabutylammonium] 64% 59% [WO(O.sub.2).sub.2F•H.sub.2O][tetrabutylammonium] 40% 38% [MoO(O.sub.2).sub.2Cl•H.sub.2O][dodecyltrimethylammonium] 40% 37%

Example 4: Oxidative Cleavage of Cyclohexene

[0112] A reactor (external diameter 16 mm, 15 ml) equipped with a 10×5 mm magnetic bar is charged with dodecyltrimethyl ammonium chlorooxodiperoxotungstate catalyst (44.7 mg; 0.08 mmol; 0.029 eq.) and then with cyclohexene (9900 purity) (234.9 mg; 2.83 mmol; 1.0 eq.). 600% (w/V) aqueous hydrogen peroxide solution (960 al; 16.93 mmol; 5.9 eq.) is then added to this mixture.

[0113] The reaction mixture is heated by contact with a metal heating block (DrySyn block, Asynt) already preheated to 90° C., with stirring at 1000 revolutions/min, for 5 h. During the reaction, the reaction medium becomes monophasic and completely clear. On completion of the reaction, the medium is allowed to cool to 25° C., letting a white solid appear at the bottom of the reactor.

[0114] Analysis of the reaction and quantification by .sup.1H NMR: an internal standard, 1,4-dibromobenzene (669.5 mg; 2.83 mmol), is then added to a 25 ml volumetric flask and then the entire reaction medium is homogenized with d6-DMSO before being added to the volumetric flask. The latter is then made up to volume with deuterated dichloromethane until the internal standard has completely dissolved and then with d6-DMSO up to the graduation mark. .sup.1H NMR analysis of this mixture is carried out and makes it possible to calculate a 90% molar yield of adipic acid.