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EP-4735171-A1 - RECYCLING OF HOMOGENEOUS PALLADIUM CATALYST

EP4735171A1EP 4735171 A1EP4735171 A1EP 4735171A1EP-4735171-A1

Abstract

The present invention relates to the field of catalysis and, more particularly, to methods for recovering palladium in a form of a homogeneous palladium complex of formula (I) from a reaction mixture comprising a homogeneous palladium complex.

Inventors

  • JERPHAGNON, Thomas

Assignees

  • Firmenich SA

Dates

Publication Date
20260506
Application Date
20240620

Claims (12)

  1. 1. A method for recovering palladium in a form of a palladium complex of formula (I) Pd(PR 1 3 )x(PR 2 3) y (I) wherein x is an integer comprised between 1 and 4; y is a integer comprised between 0 and 3 provided that the sum between x and y is equal to 4; each R 1 , independently from each other, is a C1-C12 alkyl group, a C1-C12 alkoxy group, a C6-C12 aryloxy group or a C6-C12 aryl group; each optionally substituted by one or more of a halogen atom, a C1-6 alkyl group, a C1-6 alkoxy group, a hydroxy group, a N- C1-6 alkylaniline group, A-C1-6 alkyl- A-C1-6 alkylaniline group or a C1-6 halo- or perhalo hydrocarbon; each R 2 , independently from each other, is a C1-C12 alkyl group, a C1-C12 alkoxy group, a C6-C12 aryloxy group or a C6-C12 aryl group; each optionally substituted by one or more of a halogen atom, a C1-6 alkyl group, a C1-6 alkoxy group, a hydroxy group, a N- C1-6 alkylaniline group, A-C1-6 alkyl- A-C1-6 alkylaniline group or a C1-6 halo- or perhalo hydrocarbon; and provided that PRS is different from PR 2 3; from a reaction mixture comprising a homogeneous palladium complex; said method comprises the steps of a) adding to the reaction mixture at least one phosphine of formula PRS wherein R 1 as the same meaning as defined above and optionally another phosphine of formula PR 2 3 wherein R 2 as the same meaning as defined above; b) distilling the reaction mixture obtained from step a) to obtain a distillate and a distillation residue; and c) filtrate the distillation residue to obtain the palladium complex of formula (I).
  2. 2. A method for recovering palladium in a form of a palladium complex of formula (I) Pd(PR 1 3 )x(PR 2 3) y (I) wherein x is an integer comprised between 1 and 4; y is a integer comprised between 0 and 3 provided that the sum between x and y is equal to 4; each R 1 , independently from each other, is a C1-C12 alkyl group, a C1-C12 alkoxy group, a C6-C12 aryloxy group or a C6-C12 aryl group; each optionally substituted by one or more of a halogen atom, a C1-6 alkyl group, a C1-6 alkoxy group, a hydroxy group, a N- C1-6 alkylaniline group, A-C1-6 alkyl- A-C1-6 alkylaniline group or a C1-6 halo- or perhalo hydrocarbon; each R 2 , independently from each other, is a C1-C12 alkyl group, a C1-C12 alkoxy group, a C6-C12 aryloxy group or a C6-C12 aryl group; each optionally substituted by one or more of a halogen atom, a C1-6 alkyl group, a C1-6 alkoxy group, a hydroxy group, a N- C1-6 alkylaniline group, A-C1-6 alkyl- A-C1-6 alkylaniline group or a C1-6 halo- or perhalo hydrocarbon; and provided that PRS is different from PR 2 3; from a reaction mixture comprising a homogeneous palladium complex; said method comprises the steps of i) distilling the reaction mixture comprising the homogeneous palladium complex to obtain a distillate and a distillation residue; ii) adding to the distillation residue at least one phosphine of formula PRS wherein R 1 as the same meaning as defined above and optionally another phosphine of formula PR 2 3 wherein R 2 as the same meaning as defined above; iii) mixing the distillation residue comprising phosphine obtained from step ii) to obtain a distillation residue comprising the palladium complex of formula (I); and iv) filtrate the distillation residue comprising the palladium complex of formula (I) to obtain the palladium complex of formula (I).
  3. 3. The method according to claims 1 or 2, wherein the distillation is performed in the presence of a solvent having a high boiling point.
  4. 4. The method according to any one of claims 1 to 3, wherein x is 4 and y is 0.
  5. 5. The method according to any one of claims 1 to 4, wherein each R 1 , independently from each other, is a Ci-Ce alkyl group, a Ci-Ce alkoxy group, a Ce-Cio aryloxy group or a O.-Cio aryl group; each optionally substituted by one or more of a halogen atom, a C alkyl group, a C alkoxy group, a hydroxy group, a N- C alkylaniline group, JV-CM alkyl- JV-CM alkylaniline group or a C halo- or perhalo hydrocarbon.
  6. 6. The method according to any one of claims 1 to 5, wherein each R 1 , independently from each other, is a methyl group or a phenyl group optionally substituted by one or more of a halogen atom, a C alkyl group, a C alkoxy group, a hydroxy group, a N- C alkylaniline group, 2V-C alkyl- JV-CM alkylaniline group or a C halo- or perhalo hydrocarbon.
  7. 7. The method according to any one of claims 1 to 6, wherein PRS is triphenyl phosphine.
  8. 8. The method according to any one of claims 1 to 7, wherein the reaction mixture comprising a homogeneous palladium complex is coming from a reaction catalysed by a homogeneous palladium (0), palladium (I) or palladium (II) complex.
  9. 9. The method according to any one of claims 1 to 8, wherein the homogeneous palladium (II) complex is selected from the group consisting of palladium acetate; palladium acetylacetonate, allylpalladium chloride dimer, crotylpalladium chloride dimer, cinnamylpalladium chloride dimer, dihalobis(acetonitrile)palladium, dihalo- bis(benzonitrile)palladium, dichlorobisphosphinepalladium, diphosphine palladium acetate, dichlorodiphosphinepalladium, dihalo(l,5-cyclooctadiene)palladium and dihalo(l,10-phenanthroline)palladium; the homogeneous palladium (0) complex is selected from the group consisting of palladium tetrakistriarylphosphine, palladium diphosphine, palladium triphosphine, bis(dibenzylideneacetone)palladium and tris(dibenzylideneacetone)dipalladium; the homogeneous palladium (I) complex is selected from the group consisting of monophosphine palladium halide dimer.
  10. 10. The method according to any one of claims 1 to 9, wherein palladium complex of formula (I) obtained after the filtration is further washed with organic solvent.
  11. 11. The method according to any one of claims 1 to 10, wherein the method of the invention is performed in absence of base, additive, reductive agent or oxidative agent.
  12. 12. A distillation residue comprising a solvent having a high boiling point and a palladium complex of formula (I) Pd(PR 1 3 )x(PR 2 3) y (I) wherein x is an integer comprised between 1 and 4; y is a integer comprised between 0 and 3 provided that the sum between x and y is equal to 4; each R 1 , independently from each other, is a C1-C12 alkyl group, a C1-C12 alkoxy group, a C6-C12 aryloxy group or a C6-C12 aryl group; each optionally substituted by one or more of a halogen atom, a C1-6 alkyl group, a C1-6 alkoxy group, a hydroxy group, a N- C1-6 alkylaniline group, A-C1-6 alkyl- A-C1-6 alkylaniline group or a C1-6 halo- or perhalo hydrocarbon; each R 2 , independently from each other, is a C1-C12 alkyl group, a C1-C12 alkoxy group, a C6-C12 aryloxy group or a C6-C12 aryl group; each optionally substituted by one or more of a halogen atom, a C1-6 alkyl group, a C1-6 alkoxy group, a hydroxy group, a N- C1-6 alkylaniline group, A-C1-6 alkyl- A-C1-6 alkylaniline group or a C1-6 halo- or perhalo hydrocarbon; and provided that PR '3 is different from PR 2 3.

Description

RECYCLING OF HOMOGENEOUS PALLADIUM CATALYST Technical field The present invention relates to the field of catalysis and, more particularly, to methods for recovering palladium in a form of a homogeneous palladium complex of formula (I) from a reaction mixture comprising a homogeneous palladium complex. Background In organic chemistry, one of a major breakthrough was the discovery of catalysed reactions, in particular the reactions performed in the presence of a metal complex acting as a catalyst. Said discovery allows since decades to develop novel reactions such as cross-coupling, C-H activation, addition to unsaturated bond, intra or intermolecular cyclisation, elimination, allylic substitution, hydrogenation, hydroformylation or isomerization. Homogeneous palladium complex represents one of the catalysts widely developed and the most employed. Awareness of climate and environment issues increases and the development of such type of reaction falls within this trend. Indeed, metal-complex catalysed reactions represents one of the twelve principles of green chemistry aiming at reducing the environmental impact of organic chemistry. The reduction of the waste generated during a chemical reaction is also highly sought. The homogeneous palladium complexes involved in such reactions are part of the waste and are note necessary recovered at the end of the reaction. Today, there is a need to limit the waste and to recover/recycle as much as possible the metal complex although only a small amount is involved in such transformation. The present invention allows recovering palladium in a form of a homogeneous palladium complex of formula (I) from a reaction mixture comprising a homogeneous palladium complex by adding phosphine during the distillation of the reaction mixture or in the distillation residue. To the best of our knowledge, the invention’s method has never been reported in the prior art. Description of the invention Surprisingly, the present invention’s methods allow recovering palladium in a form of a homogeneous palladium complex of formula (I) in an easy and highly productive manner. So a first object of the present invention is a method for recovering palladium in a form of a palladium complex of formula (I) Pd PR^x PR^y (I) wherein x is an integer comprised between 1 and 4; y is a integer comprised between 0 and 3provided that the sum between x and y is equal to 4; each R1, independently from each other, is a C1-C12 alkyl group, a C1-C12 alkoxy group, a C6-C12 aryloxy group or a C6-C12 aryl group; each optionally substituted by one or more of a halogen atom, a C1-6 alkyl group, a C1-6 alkoxy group, a hydroxy group, a N- C1-6 alkylaniline group, N-Cis alkyl- N-Cis alkylaniline group or a C1-6 halo- or perhalo hydrocarbon; each R2, independently from each other, is a C1-C12 alkyl group, a C1-C12 alkoxy group, a C6-C12 aryloxy group or a C6-C12 aryl group; each optionally substituted by one or more of a halogen atom, a C1-6 alkyl group, a C1-6 alkoxy group, a hydroxy group, a N- C1-6 alkylaniline group, N-Cis alkyl- iV-Ci-6 alkylaniline group or a C1-6 halo- or perhalo hydrocarbon; and provided that PRS is different from PR23; from a reaction mixture comprising a homogeneous palladium complex; said method comprises the step of a) adding to the reaction mixture at least one phosphine of formula PRS wherein R1 as the same meaning as defined above and optionally another phosphine of formula PR23 wherein R2 as the same meaning as defined above; b) distilling the reaction mixture obtained from step a) to obtain a distillate and a distillation residue; and c) filtrate the distillation residue to obtain the palladium complex of formula (I). For the sake of clarity, by the expression “x is an integer comprised between 1 and 4; y is a integer comprised between 0 and 3 provided that the sum between x and y is equal to 4”, or the similar, it is meant the normal meaning understood by a person skilled in the art, i.e. x may be 1, 2 ,3 or 4 and y may be 0,1, 2 or 3 and x+y is equal to 4. For example, when x is 4, then y is 0 or when x is 2 then y is 2 or when x is 3, then y is 1. The terms “alkyl”, “alkoxy”, “N- Ci-6 alkylaniline group” and N-Cis alkyl- N-Cis alkylaniline group are understood as comprising branched and linear alkyl, alkoxy, N- Ci- 6 alkylaniline and iV-Ci-6 alkyl- N-Cis alkylaniline groups. The term “N- Ci-6 alkylaniline” is understood as a secondary amine of formula - NH-R’ wherein R’ is a Ci-6 alkyl group. The term ‘W-Ci-6 alkyl- A-CI-6 alkylaniline” is understood as a tertiary amine of formula -NR’R” wherein R’ and R”, independently from each other, are a Ci-6 alkyl group. The term “aryl” is understood as comprising any group comprising at least one aromatic group such as phenyl, indenyl, indanyl, benzodioxolyl, dihydrobenzodioxinyl, tetrahydronaphthalenyl or naphthalenyl group. The term “optionally” is understood that a certain group to be optionally substituted can or cannot be substituted