Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07B—GENERAL METHODS OF ORGANIC CHEMISTRY; APPARATUS THEREFOR
  • C07B41/00—Formation or introduction of functional groups containing oxygen
  • C07B41/08—Formation or introduction of functional groups containing oxygen of carboxyl groups or salts, halides or anhydrides thereof
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
  • C07C51/15—Preparation of carboxylic acids or their salts, halides or anhydrides by reaction of organic compounds with carbon dioxide, e.g. Kolbe-Schmitt synthesis
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07B—GENERAL METHODS OF ORGANIC CHEMISTRY; APPARATUS THEREFOR
  • C07B41/00—Formation or introduction of functional groups containing oxygen
  • C07B41/08—Formation or introduction of functional groups containing oxygen of carboxyl groups or salts, halides or anhydrides thereof
  • C07B41/10—Salts, halides or anhydrides of carboxyl groups
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
  • C07C51/41—Preparation of salts of carboxylic acids
  • C07C51/412—Preparation of salts of carboxylic acids by conversion of the acids, their salts, esters or anhydrides with the same carboxylic acid part

Definitions

• the present invention relates to a process for preparing an alkali metal or alkaline earth metal salt of an ⁇ -ethylenically unsaturated carboxylic acid by catalytic carboxylation of alkenes. More particularly, the invention relates to a process for preparing sodium acrylate by direct carboxylation of ethene with carbon dioxide (CO2). Acrylic acid and derivatives thereof are important industrial chemicals and monomer units for production of water-absorbing resins, called superabsorbents.
• a ligand and a homogeneous Ni(0) species such as bis(1 ,5-cyclooctadiene)nickel (Ni(COD)2) in the presence of CO2 readily form a ligand- N1-CO2 adduct (scheme 2), which is thermally labile, and one way in which it decomposes is with oxidation of the ligand, even at low temperatures of 80°C. This is disadvantageous since the potential catalyst or precursors thereof are thus degraded.
• Nickelalactones A may bear one or more ligands and arise from the direct and stoichiometric coupling of CO2 and ethylene, as found by Hoberg (J. Organomet.
• the transformation gives, as well as methyl propionate, which indicates an unproductive decomposition of the nickelalactone, low yields of methyl acrylate (max. 33%); no catalysis cycle was described. In the case of use of Lil, at best only traces of methyl acrylate were found.
• the nickelalactones used bear the ligands diphenylphosphinopropane (dppp), diphenylphosphinoethane (dppe) and tetramethylethylenediamine (TMEDA).
• the two former lactones were prepared by ligand exchange of the lactone prepared from Ni(COD)2, TMEDA and succinic anhydride, and none of the lactones were synthesized proceeding from CO2 and ethylene in a one-pot reaction (Organometallics 2010, 29, 2199).
• WO 201 1/107559 discloses a process for preparing an alkali metal or alkaline earth metal salt of an ⁇ -ethylenically unsaturated carboxylic acid, wherein a) an alkene, CO2 and a carboxylation catalyst are converted to an alkene/C02/carboxylation catalyst adduct, b) the adduct is decomposed to release the carboxylation catalyst with an auxiliary base to give the auxiliary base salt of the ⁇ -ethylenically unsaturated carboxylic acid, c) the auxiliary base salt of the ⁇ -ethylenically unsaturated carboxylic acid is reacted to release the auxiliary base with an alkali metal or alkaline earth metal base to give the alkali metal or alkaline earth
• the process achieves the cleavage of the intermediate adduct by means of an auxiliary base, for example of a tertiary amine, in order to prepare, in a first step, the ammonium salt of the ⁇ -ethylenically unsaturated carboxylic acid, which overcomes the fundamental thermodynamic limitation.
• a second step for example with aqueous sodium hydroxide solution, the ammonium cation is exchanged for sodium, in order thus to obtain the sodium salt of the a ⁇ -ethylenically unsaturated carboxylic acid.
• This two-stage reaction regime is complex.
• the cleavage of the lactone is slow and thus reduces the space- time yield of such a process considerably.
• the invention provides a process for preparing an alkali metal or alkaline earth metal salt of an ⁇ -ethylenically unsaturated carboxylic acid, wherein a) a transition metal-alkene complex is reacted with CO2 to give a metallalactone, b) the metallalactone is reacted with a base to give an adduct of the alkali metal or alkaline earth metal salt of the ⁇ -ethylenically unsaturated carboxylic acid with the transition metal complex, the base being selected from alkali metal or alkaline earth metal hydroxides and alkali metal or alkaline earth metal superbases, and c) the adduct is reacted with an alkene to release the alkali metal or alkaline earth metal salt of the ⁇ -ethylenically unsaturated carboxylic acid and regenerate the transition metal-alkene complex.
• step c) the transition metal-alkene complex is regenerated and is available again for step a).
• transition metal complex used in the present application comprises, in a generic manner, all transition metal complexes through which a catalytic cycle passes, especially the transition metal-alkene complex, the metallalactone and the adduct of the alkali metal or alkaline earth metal salt of the ⁇ -ethylenically unsaturated carboxylic acid with the transition metal complex.
• transition metal-alkene complex should be interpreted broadly and describes any possible coordination known to those skilled in the art of alkenes to transition metal centers.
• the transition metal-alkene complex can be illustrated by the general formula I
• M is a transition metal
• L is a ligand
• n 1 or 2
• R a , R b and R c are each independently hydrogen, Ci-12-alkyl, C2-i2-alkenyl, or R a and R b together with the carbon atoms to which they are bonded are a mono- or diethylenically unsaturated, 5- to 8-membered carbocycle.
• M is preferably an active metal defined below, especially nickel, iron or rhodium, more preferably nickel.
• L is preferably a ligand defined below.
• R c is hydrogen; more preferably, R b and R c are each hydrogen; especially preferably, R a , R b and R c are each hydrogen.
• transition metal-alkene complex shall comprise isolable and unstable intermediates of the general formula I.
• metallalactone denotes, according to the exchange nomenclature ("a” nomenclature), a lactone (y-lactone) in which a carbon atom has been exchanged for a metal atom.
• a nomenclature
• lactone y-lactone
• the expression “metallalactone” should be interpreted broadly and may comprise compounds with structures similar to the Hoberg complex mentioned at the outset, or related compounds of oligomeric or polymeric structure.
• the expression shall comprise isolable compounds and (unstable) intermediates.
• the metallalactone can be illustrated by the general formula II
• M, L, n, R a , R b and R c are each as already defined and M' is an alkali metal or the equivalent of an alkaline earth metal.
• the transition metal complex comprises, as the active metal, at least one element of groups 4 (preferably Ti, Zr), 6 (preferably Cr, Mo, W), 7 (preferably Re), 8 (preferably Fe, Ru), 9 (preferably Co, Rh) and 10 (preferably Ni, Pd, Pt) of the Periodic Table of the Elements.
• groups 4 preferably Ti, Zr
• 6 preferably Cr, Mo, W
• 7 preferably Re
• 8 preferably Fe, Ru
• 9 preferably Co, Rh
• 10 preferably Ni, Pd, Pt
• the transition metal complex comprises a complex of nickel, iron or rhodium.
• the transition metal complex comprises a complex of nickel or palladium.
• the role of the active metal consists in the activation of CO2 and alkene in order to form a C-C bond between CO2 and the alkene.
• the transition metal-alkene complex comprises a ligand L.
• the ligand stabilizes the metallalactone formed from the transition metal-alkene complex.
• the ligand is selected such that it leaves coordination sites for the alkene and CO2 unoccupied on the metal.
• the ligand may be monodentate or polydentate, for example bidentate.
• the polydentate, e.g. bidentate, ligand coordinates to the transition metal to form a five-membered ring, i.e. the transition metal, the atoms which coordinate to the transition metal and the atoms of the shortest chain which connects the atoms coordinating to the transition metal together form a five-membered ring.
• the ligand L may comprise at least one phosphorus atom, nitrogen atom, oxygen atom and/or carbene group which coordinates to the transition metal.
• the ligand L may be selected, for example, from phosphines, phosphites, amines and A/-heterocyclic carbenes.
• the ligand L preferably comprises at least one phosphorus atom and/or carbene group which coordinates to the transition metal. More particularly, the ligand L comprises at least one phosphorus atom which coordinates to the transition metal.
• at least one radical is preferably bonded to the phosphorus atom via a secondary or tertiary carbon atom. More particularly, at least two radicals are bonded to the phosphorus atom via a secondary or tertiary carbon atom.
• Suitable radicals bonded to the phosphorus atom via a secondary or tertiary carbon atom are, for example, adamantyl, ferf-butyl, sec-butyl, isopropyl, phenyl, tolyl, xylyl, mesityl, naphtyl, fluorenyl or anthracenyl, especially ferf-butyl or phenyl.
• the ligand L comprises at least one A/-heterocyclic carbene which coordinates to the transition metal
• at least one radical is preferably bonded via a tertiary carbon atom to at least one -nitrogen atom to the carbene group.
• Suitable radicals bonded to the nitrogen atom via a tertiary carbon atom are, for example, adamantyl or ferf-butyl, especially ferf-butyl.
• the ligand is a bidentate ⁇ , ⁇ , ⁇ , ⁇ , P,0 or P, carbene ligand.
• the bidentate ⁇ , ⁇ , ⁇ , ⁇ , P,0 or P, carbene ligand preferably coordinates to the transition metal to form a five-membered ring.
• Suitable monodentate ligands have, for example, the formula V
• R 1 , R 2 and R 3 are each independently alkyl, cycloalkyl or aryl.
• Suitable monodentate ligands are also A/-heterocyclic carbenes of the formula VI
• R 11 and R 12 are each independently alkyl or aryl
• R 13 , R 14 , R 15 and R 16 are each independently hydrogen, alkyl or aryl
• R 15 and R 16 together are a chemical bond.
• Suitable bidentate ligands L have the general formula VII L -(CR 4 R 5 ) m -L 2 VII in which
• L 1 is PR 1 R 2 or P(0)R 1 R 2 ,
• L 2 is PR R 2 , P(0)R 1 R 2 , NR R 2 , COO " , an A/-heterocyclic carbene radical of the formula VIII
• VIM in which * is the bonding site to the rest of the molecule
• R 12 , R 13 , R 14 , R 15 and R 16 are each as already defined, or a pyridine radical of the formula IX
• R 21 , R 22 , R 23 and R 24 are each independently hydrogen, alkyl or aryl
• R 1 and R 2 are each as already defined
• R 4 and R 5 are each independently hydrogen, alkyl or aryl
• n 1 or 2.
• alkyl comprises straight- chain and branched alkyl groups.
• these are Ci-C2o-alkyl, preferably C1-C12- alkyl, more preferably Ci-Cs-alkyl and most preferably Ci-C4-alkyl.
• alkyl groups are especially methyl, ethyl, propyl, isopropyl, n-butyl, 2-butyl, sec-butyl, tert- butyl, n-pentyl, 2-pentyl, 2-methylbutyl, 3-methylbutyl, 1 ,2-dimethylpropyl,
• alkyl comprises unsubstituted and substituted alkyl groups which have generally 1 , 2, 3, 4 or 5 and preferably 1 , 2 or 3 substituents, and more preferably 1 substituent. These are preferably selected from alkoxy, cycloalkyl, aryl, hetaryl, hydroxyl, halogen, NE 1 E 2 , NE 1 E 2 E 3+ , carboxylate and sulfonate.
• alkoxy, cycloalkyl, aryl, hetaryl, hydroxyl, halogen, NE 1 E 2 , NE 1 E 2 E 3+ , carboxylate and sulfonate are preferably selected from alkoxy, cycloalkyl, aryl, hetaryl, hydroxyl, halogen, NE 1 E 2 , NE 1 E 2 E 3+ , carboxylate and sulfonate.
• perfluoroalkyl group is trifluoromethyl
• cycloalkyl comprises monocyclic and polycyclic alkyl groups, especially monocyclic, bicyclic or tricyclic alkyl groups. Preferably, they are C3-C20- cycloalkyl, preferably C4-Ci2-cycloalkyl, more preferably Cs-Cs-cycloalkyl.
• alkyl groups are cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl or adamantyl.
• cycloalkyl comprises unsubstituted and substituted cycloalkyl groups which have generally 1 , 2, 3, 4 or 5 and preferably 1 , 2 or 3 substituents, and more preferably 1 substituent. These are preferably selected from alkoxy, aryl, hetaryl, hydroxyl, halogen, NE 1 E 2 , NE 1 E 2 E 3+ , carboxylate and sulfonate.
• aryl in the context of the present invention comprises unsubstituted and also substituted aryl groups, and is preferably C6-Ci8-aryl, such as phenyl, tolyl, xylyl, mesityl, naphthyl, fluorenyl, anthracenyl, phenanthrenyl or naphthacenyl, more preferably phenyl or naphthyl, where these aryl groups in the case of substitution may bear generally 1 , 2, 3, 4 or 5 and preferably 1 , 2 or 3 substituents, and more preferably 1 substituent, selected from the alkyl, alkoxy, carboxylate, trifluoromethyl, sulfonate, NE 1 E 2 , alkylene-NE 1 E 2 , nitro, cyano or halogen groups.
• C6-Ci8-aryl such as phenyl, tolyl, xylyl, mesityl, naphthyl, fluorenyl
• a preferred perfluoroaryl group is pentafluorophenyl.
• Carboxylate and sulfonate in the context of this invention are preferably a derivative of a carboxylic function and of a sulfonic acid function respectively, especially a metal carboxylate or sulfonate, a carboxylic ester or sulfonic ester function, or a carboxamide or sulfonamide function. Examples of these include the esters with Ci-C4-alkanols, such as methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol and tert- butanol.
• the E 1 , E 2 and E 3 radicals are each independently selected from hydrogen, alkyl, cycloalkyl and aryl.
• the NE 1 E 2 group is preferably A/,A/-dimethylamino, N,N- diethylamino, A/,A/-dipropylamino, A/,A/-diisopropylamino, A/,A/-di-n-butylamino, ⁇ , ⁇ - ⁇ - ferf-butylamino, A/,A/-dicyclohexylamino or A/,A/-diphenylamino.
• Halogen is fluorine, chlorine, bromine and iodine, preferably fluorine, chlorine and bromine.
• W in the formula V is P.
• At least one radical, especially at least two radicals, of the R 1 , R 2 and R 3 radicals is adamantyl, ferf-butyl, sec-butyl, isopropyl, phenyl, tolyl, xylyl, mesityl, naphtyl, fluorenyl or anthracenyl, especially ferf-butyl or phenyl.
• R 11 and R 12 are preferably each adamantyl, feri-butyl, sec-butyl, isopropyl, phenyl, tolyl, xylyl, mesityl, naphtyl, fluorenyl or anthracenyl, especially ferf- butyl or phenyl.
• R 13 , R 14 , R 15 and R 16 are preferably each independently hydrogen or alkyl, especially hydrogen or Ci-C4-alkyl, more preferably hydrogen, or R 15 and R 16 together are a chemical bond.
• L 1 is preferably PR 1 R 2 .
• L 2 is preferably PR 1 R 2 , an A/-heterocyclic carbene radical of the formula VIII or a pyridine radical of the formula IX.
• L 1 and L 2 are each PR 1 R 2 .
• R 4 and R 5 are preferably each independently hydrogen or C1-C4- alkyl; more particularly, (CR 4 R 5 ) m is -CH 2 - or -CH 2 -CH 2 -.
• at least one radical of the R 1 and R 2 radicals, especially both of the R 1 and R 2 radicals, (per phosphorus atom) is adamantyl, ferf-butyl, sec- butyl, isopropyl, phenyl, tolyl, xylyl, mesityl, naphtyl, fluorenyl or anthracenyl, especially ferf-butyl or phenyl.
• R 12 is preferably adamantyl, ferf-butyl, sec-butyl, isopropyl, phenyl, tolyl, xylyl, mesityl, naphtyl, fluorenyl or anthracenyl, especially ferf-butyl or phenyl.
• R 13 , R 14 , R 15 and R 16 are preferably each independently hydrogen or alkyl, especially hydrogen or Ci-C4-alkyl, more preferably hydrogen, or R 15 and R 16 together are a chemical bond.
• Preferred representatives of the formula VI I are
• At least one equivalent of the anion from the base may itself function as a ligand on the metal of the transition metal complex.
• the transition metal complex may also have at least one further ligand selected from halides, amines, amides, oxides, phosphides, carboxylates, acetylacetonate, aryl- or alkylsulfonates, hydride, CO, olefins, dienes, cycloolefins, nitriles, aromatics and heteroaromatics, ethers, PF3, phospholes, phosphabenzenes, and mono-, di- and polydentate phosphinite, phosphonite, phosphoramidite and phosphite ligands.
• halides amines, amides, oxides, phosphides, carboxylates, acetylacetonate, aryl- or alkylsulfonates, hydride, CO, olefins, dienes, cycloolefins, nitriles, aromatics and heteroaromatics, ether
• Suitable alkenes are those of the formula IX
• R a , R b and R c are each as already defined.
• Suitable alkenes are, for example, ethene, propene, isobutene, butadiene, piperylene, 1 -butene, 1 -pentene, 1 -hexene, 1 -heptene, 1 -octene, 1 -nonene, 1 -decene.
• the alkene to be used in the carboxylation is generally gaseous or liquid under the reaction conditions.
• the alkene is ethene.
• the process according to the invention makes it possible to obtain alkali metal or alkaline earth metal acrylates, especially sodium acrylate.
• the transition metal-alkene complex used in step a) can initially be obtained by reacting the alkene and a transition metal precomplex to give the transition metal- alkene complex.
• the transition metal precomplex comprises a ligand L and may comprise at least one further ligand which can be displaced by the alkene.
• the transition metal-alkene complex can be obtained initially by reacting a transition metal source with a ligand L and an alkene to give the transition metal-alkene complex.
• Useful transition metal sources include commercial standard complexes, for example [M(p-cymene)CI 2 ] 2 , [M(benzene)CI 2 ]n, [M(COD) 2 ], [M(CDT)], [M(C 2 H 4 ) 3 ], [MCI 2 xH 2 0], [MCI 3 xH 2 0], [M(acetylacetonate) 3 ], [M(DMSO) 4 CI 2 ], where M is as already defined.
• the transition metal-alkene complex, the metallalactone and the adduct of the alkali metal or alkaline earth metal salt of the ⁇ -ethylenically unsaturated carboxylic acid with the transition metal complex are present in
• the solvent selected is one in which the transition metal complex has good solubility.
• examples include aromatic hydrocarbons such as benzene, toluene or xylene, halogenated aromatic hydrocarbons such as chlorobenzene, ethers such as tetrahydrofuran, alcohols such as methanol, ethanol, isopropanol, dimethylformamide, dimethyl sulfoxide and water, or any mixtures of these solvents with one another, for example chlorobenzene/methanol or methanol/water.
• a preferred solvent is chlorobenzene.
• step a the transition metal-alkene complex is reacted with C0 2 to give a
• the metallalactone is reacted with a base to give an adduct of the alkali metal or alkaline earth metal salt of the ⁇ -ethylenically unsaturated carboxylic acid with the transition metal complex.
• the base used is selected from alkali metal or alkaline earth metal hydroxides and alkali metal or alkaline earth metal superbases.
• a superbase is understood to mean a base which reacts on contact with water quantitatively to give hydroxide ions and the corresponding acid of the superbase.
• a base whose base strength corresponds to or is higher than that of hydroxide ions is used.
• the bases used are sufficiently basic to deprotonate the metallalactone in the a position.
• the alkali metal or alkaline earth metal cation is probably capable, due to its Lewis acidity, of stabilizing the carboxylate group which forms.
• the base can be added in solid form or as a solution. Preferably, however, a solution of the base is added.
• the base solvent may be different than or identical to the reaction solvent.
• the base solvent is preferably at least partly miscible with the reaction solvent.
• the alkali metal is preferably selected from lithium, sodium and potassium; more particularly, the alkali metal is sodium.
• the alkaline earth metal is preferably selected from magnesium, calcium, strontium and barium.
• Suitable alkali metal hydroxides are, for example, NaOH, KOH or LiOH.
• an aqueous solution of the hydroxide is sufficient.
• a solubilizer can optionally be added, for example an alcohol.
• the alkali metal or alkaline earth metal superbase is preferably selected from alkali metal or alkaline earth metal alkoxides, alkali metal or alkaline earth metal hydrides, alkali metal or alkaline earth metal azides, alkali metal or alkaline earth metal phosphides, alkali metal or alkaline earth metal silanolates, alkali metal or alkaline earth metal alkyls and alkali metal or alkaline earth metal aryls.
• Suitable alkali metal or alkaline earth metal alkoxides are Ci-i6-alkoxides, preferably Ci-i2-alkoxides, especially Ci-4-alkoxides.
• Suitable alkoxides derive from alcohols of the formula R 100 OH.
• Suitable R 100 radicals are branched or unbranched, acyclic or cyclic alkyl radicals having 1 -16 carbon atoms, preferably 1 -12 carbon atoms, which are unsubstituted or wherein individual carbon atoms may each independently also be replaced by a heteroatom selected from the group of O and >N.
• Suitable R 1 radicals are benzyl, methyl, ethyl, 1 -propyl, 2-propyl, 1 -butyl, 2-butyl, 2-(2-methyl)propyl, 1 -(2-methyl)propyl, 1 -(2-methyl)butyl, 2-(2-methyl)propyl, 1 -pentyl, 1 -(2-methyl)pentyl, 1 -hexyl, 1 -(2-ethyl)hexyl, 1 -heptyl, 1-(2-propyl)heptyl, 1 -octyl, 1 -nonyl, 1 -decyl,
• Suitable alkali metal or alkaline earth metal alkoxides are sodium methoxide, sodium ethoxide, sodium isopropoxide, sodium ferf-butoxide. In the case of the alkoxides, the alcohol itself may serve as the solvent. Sodium feri-butoxide is a preferred base.
• Suitable alkali metal or alkaline earth metal hydrides are, for example, lithium hydride, sodium hydride, potassium hydride, and magnesium hydride, calcium hydride.
• the suitable amides also include silicon-containing amides such as sodium hexamethyldisilazide (NaHMDS), potassium hexamethyldisilazide (KHMDS) or lithium hexamethyldisilazide (LiHMDS).
• silicon-containing amides such as sodium hexamethyldisilazide (NaHMDS), potassium hexamethyldisilazide (KHMDS) or lithium hexamethyldisilazide (LiHMDS).
• Suitable alkali metal or alkaline earth metal silanolates are those of the formula MOSi(Ci-4-Alkyl)3 in which M is an alkali metal or an equivalent of an alkaline earth metal, for example NaOSiMe3.
• Suitable alkali metal or alkaline earth metal alkyls or aryls are lithium alkyl compounds, such as methyllithium, n-butyllithium, seobutyllithium, ferf-butyllithium, phenyllithium, where the benzene ring may bear substituents at any position (e.g. OCH3, CH 2 NMe 2 , CONR 2 ), cyclohexyllithium, where the cyclohexyl ring may comprise heteroatoms (e.g. O, N, S), ethyllithium, lithium pentadienyl, lithium 2-furanyl, lithium 2-thiophenyl, lithium ethynyl.
• sodium alkyl compounds such as sodium cyclopentadienyl.
• the suitable alkaline earth metal alkyls include magnesium alkyl compounds (Grignard reagents) of the general formula R 1 MgX, where R 1 may be one of the radicals listed above and X may be F, CI, Br, I.
• the base can be used in a stoichiometric amount or in a superstoichiometric amount, based on the metallalactone.
• the amount of base used per catalytic cycle is preferably 1 to 2, more preferably 1 to 1 .1 , equivalents based on the metallalactone.
• step c) the adduct is reacted with an alkene.
• the alkene displaces the alkali metal or alkaline earth metal salt of the ⁇ -ethylenically unsaturated carboxylic acid from the coordination site on the active metal.
• the transition metal-alkene complex is regenerated and is available for a new catalytic cycle. This completes the catalytic cycle.
• the displaceability of the alkali metal or alkaline earth metal salt of the a ⁇ -ethylenically unsaturated carboxylic acid from the adduct is surprising since the adduct of free acrylic acid with the transition metal complex IV does not exhibit this reaction.
• the initial formation of the transition metal-alkene complex (or the regeneration of the transition metal-alkene complex according to step c) in the second and further catalytic cycles) and step a) of the process can be performed separately from one another, by adding the alkene and CO2 in succession or in spatial separation from one another.
• the initial formation (or the regeneration of the transition metal-alkene complex according to step c) in the second and further catalytic cycles) and step a) of the process can, however, also be performed essentially simultaneously, by adding the alkene and CO2 simultaneously or adding a mixture of alkene and CO2.
• the CO2 for use in the reaction can be used in gaseous, liquid or supercritical form. It is also possible to use carbon dioxide-comprising gas mixtures available on the industrial scale, provided that they are substantially free of carbon monoxide.
• CO2 and alkene may also comprise inert gases such as nitrogen or noble gases.
• the content thereof is below 10 mol%, based on the total amount of carbon dioxide and alkene in the reactor.
• the molar ratio of carbon dioxide to alkene in the feed is generally 0.1 to 10 and preferably 0.5 to 5.
• the transition metal-alkene complex is the first to form with the alkene.
• the base is preferably added separately from the addition of the CO2 in order to prevent a direct reaction of the base with the CO2.
• the base is therefore preferably added at a different time than the addition of the CO2.
• the reactors used may in principle be all reactors which are suitable in principle for gas/liquid reactions or liquid/liquid reactions at the given temperature and the given pressure. Suitable standard reactors for liquid-liquid reaction systems are specified, for example, in K. D. Henkel, "Reactor Types and Their Industrial Application", in
• suitable apparatuses can be used.
• Such apparatuses may be mechanical stirrer apparatuses with one or more stirrers, with or without baffles, packed or nonpacked bubble columns, packed or nonpacked flow tubes with or without static mixers, or other useful apparatuses known to those skilled in the art for these process steps.
• baffles and delay structures is explicitly included in the process according to the invention.
• the reactor is filled with the reaction solvent and the transition metal precomplex, or alternatively the transition metal source and the ligand L. Subsequently, the alkene and, at the same time or a different time or a different place, CO2 are injected. After the end of each addition step, the reactor can be decompressed. At a different time or place, the base is then added. The catalytic cycle can then be repeated once or more than once, alkene and, at the same time or a different time or a different place, CO2 can be injected again, and base can be added at a different time or different place.
• Such a spatial separation can be effected, for example, in a stirred tank simply by means of two or more separate inlets. When several tanks are used, it is possible, for example, for different media charges to be effected in different tanks. Separation of the times of addition of the alkene and CO2 reactants on the one hand and the base reactant on the other hand is required in the process according to the invention.
• Such a time separation can be effected, for example in a stirred tank, by alternating the charging with the reactants.
• such charging can be effected, for example, at different sites in the flow tube; through such a variation in the addition sites, the reactants can be added as a function of residence time.
• Steps a) to c) are performed preferably in the liquid or supercritical phase at pressures between 1 and 150 bar, preferably at pressures between 1 and 100 bar, more preferably at pressures between 1 and 60 bar.
• Steps a) to c) of the process according to the invention are performed preferably at temperatures between -20°C and 300°C, more preferably at temperatures between 20°C and 250°C, especially preferably at temperatures between 40°C and 200°C.
• the alkali metal or alkaline earth metal salt of the a ⁇ -ethylenically unsaturated carboxylic acid formed in step c) is separated from the reaction medium.
• the alkali metal or alkaline earth metal salt of the a ⁇ -ethylenically unsaturated carboxylic acid may be sparingly soluble in the reaction medium and precipitate, such that it can be separated by solid-liquid phase separation, such as removal by filtration, decantation or centrifugation.
• the removal of the derivative preferably comprises a liquid-liquid phase separation into a first liquid phase in which the alkali metal or alkaline earth metal salt of the
• a ⁇ -ethylenically unsaturated carboxylic acid is enriched, and a second liquid phase in which the transition metal-alkene complex is enriched.
• the second phase generally comprises the reaction solvent.
• liquid-liquid phase separation is supported by the additional use of a polar solvent in which the derivative of the alkali metal or alkaline earth metal salt of the
• a ⁇ -ethylenically unsaturated carboxylic acid has good solubility, and which is immiscible or has only limited miscibility with the second liquid phase in which the transition metal-alkene complex is enriched.
• the polar solvent is generally selected by simple tests.
• a separation of the alkali metal or alkaline earth metal salt of the ⁇ -ethylenically unsaturated carboxylic acid is preferably effected via the separation thereof into two different phases. It is thus possible, for example, to remove the alkali metal or alkaline earth metal salt of the ⁇ -ethylenically unsaturated carboxylic acid in a polar aqueous phase from the existing organic phase. The remaining organic phase is recycled into step a). This recycling is undertaken under conditions which are favorable for the process.
• Fig. 1 shows the X-ray structure analysis of (dtbpe)nickela-y-lactone.
• Fig. 2 shows the X-ray structure analysis of the (dtbpe)Ni(// 2 -acrylic acid) complex.
• Fig. 3 shows the X-ray structure analysis of the (dtbpe)Ni(ethylene) complex.
• Fig. 4 shows the HPLC chromatogram of the reaction product from Example 7.
• Example 1 Preparation of the (dtbpe)Ni(ethylene) complex Under an argon atmosphere, dtbpe (662 mg, 2.1 mmol) and Ni(COD)2 (571 mg, 2.1 mmol) were dissolved in THF (28 ml) and transferred to an autoclave. The autoclave was charged with ethylene (15 bar). After decompression, the solvent was removed to obtain 300 mg of yellow-brown crystals (36% yield). Crystals suitable for the X-ray structure analysis were obtained at -35°C after addition of diethyl ether. The result of the X-ray structure analysis is shown in Fig. 3.
• the mixture was transferred to an autoclave and diluted with chlorobenzene (10 ml).
• the autoclave was closed and filled with ethylene (20 bar).
• the mixture was stirred at room temperature (600 rpm) for 30 min, then the autoclave was decompressed down to a pressure of 10 bar and CO2 was added up to a pressure of 50 bar.
• the mixture was heated to 45°C and stirred for 16 h (600 rpm).
• Example 2b Nickelalactone formation Ni(COD) 2 (14.4 mg, 52.3 jumol) and 3-tert-butyl-1 -(di-tert-butylphosphinomethyl)- imidazol-2-ylidene (14.7 mg, 52.1 /jmol) were dissolved in THF-cfe (0.60 ml) and transferred to a high-pressure NMR tube. The tube was charged with ethylene (6 bar) and shaken at 40°C for 6 h. The ethylene was decompressed and the tube was charged with CO2 (8 bar). The solution was heated at 40°C for 15 h. The corresponding nickelalactone was detected by spectroscopy.
• Example 3 Nickelalactone cleavage A solution of the nickelalactone from example 2 (1 1 .2 mg, 0.025 mmol) in
• chlorobenzene (1 ml) was admixed with NaOfBu (7.2 mg, 0.075 mmol) and stirred at room temperature for 1 .5 h.
• Ni(COD)2 (1.50 g, 5.45 mmol) and dtbpe (1.74 g,
• Example 5 (reference example): Preparation of a (dtbpe)Ni(// 2 -sodium acrylate) complex
• the (dtbpe)Ni ( ⁇ -sodium acrylate) complex (32.4 mg, 72.1 ⁇ ) from example 5 was dissolved in THF-cfe (0.60 ml) and charged with ethylene (8 bar) in a high-pressure NMR tube. The reaction solution was heated at 60°C for 20 h. NMR analysis showed the exclusive presence of the (dtbpe)Ni(ethylene) complex.
• Example 7 (inventive example): Catalytic formation of sodium acrylate
• Example 8 Attempted ligand exchange of (dtbpe)Ni(// 2 -acrylic acid) complex with ethylene
• the (dtbpe)Ni(// 2 -acrylic acid) complex (31 .5 mg, 70.1 /imol) was dissolved in THF-c/e (0.60 ml) and introduced into a high-pressure NMR tube. The tube was charged with ethylene and stirred at 60°C for 18 h. The NMR analysis showed the product to be a mixture of (dtbpe)Ni(ethylene) (3.1 %), (dtbpe)Ni(// 2 -acrylic acid) (95.6%) and free dtbpe ligand (1 .3%).

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Preparation Of Compounds By Using Micro-Organisms (AREA)
• Catalysts (AREA)
• Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)

Priority Applications (5)

Applications Claiming Priority (2)

Publications (1)

Family

ID=48696433

Family Applications (1)

Country Status (6)

Cited By (21)

Families Citing this family (3)

Citations (3)

• 2012
  • 2012-12-27 JP JP2014549615A patent/JP6122030B2/ja active Active
  • 2012-12-27 IN IN4656CHN2014 patent/IN2014CN04656A/en unknown
  • 2012-12-27 WO PCT/IB2012/057750 patent/WO2013098772A1/en active Application Filing
  • 2012-12-27 EP EP12861287.6A patent/EP2797869A4/en not_active Withdrawn
  • 2012-12-27 CA CA2862155A patent/CA2862155A1/en not_active Abandoned
  • 2012-12-27 CN CN201280064974.5A patent/CN104011004B/zh not_active Expired - Fee Related

Patent Citations (3)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events