FR2628102A1 - Prepn. of hydroxy:benzaldehyde deriv. - Google Patents

Abstract

A hydroxybenzaldehyde of formula (I) is prepd. by reacting a halophenol of formula (II) with a CO/H2 mixt., in presence of a catalyst based on a noble metal, of a tert. amine, and of a triaryl or diarylalkyl phosphine; the amine is such that the pKa of the conjugated acid is not above the pKa of (II) and is greated than that of phosphine. Z = electron donor or acceptor gp.; n = 0-2; X = Br or iodine;.

Description

FRENCH REPUBLIC Publication No. 2,628,102 (to be used only for

  INSTITUTE NATIONAL Reproduction Orders)

NATIONAL INSTITUTE

  OF THE PROPERTY: INDUSTRIAL INDUSTRIAL PROPERTY No. of national registration 88 02827 PARIS

  Int CI'4: C 07 C 47/565, 45/49, 47/58.

@ APPLICATION FOR PATENT OF INVENTION A1

  ) Date of deposit: 1 March 1988. (Applicant (s): RHONE POULENC CHIMIE - FR.

  (Priority È) Inventor (s): Philippe Leconte; Francois Metz; Robert Perron. ) Date of the making available to the public of the

  application: BOPI "Patents" No. 36 of 8 September 1989.

  ) References to other national documents appearing

: Holder (s):

  (Representative (s) Noël Vignally, Rhône Poulenc Interser-

  vices. Process for the preparation of hydroxybenzaldehydes by hydrocarbonylation The present invention relates to a method of preparation

  hydroxybenzaldehydes by hydrocarbonylation of the halogeno

corresponding phenols.

  More precisely, it is a process for preparing hy-

  droxybenzaldehydes by reaction of a halophenol with a carbon monoxide / hydrogen mixture, in the presence of a tertiary amine, a noble metal catalyst and

a phosphine.

  The process makes it possible in particular to prepare vanillin for

  from 4-bromo-2-methoxyphenol.

I N Co N CO * N oe

1 \ 2628102

  PROCESS FOR THE PREPARATION OF HYDROXYBENZALDEHYDES

BY HYDROCARBONYLATION

  The present invention relates to a process for the preparation of hydroxybenzaldehydes by hydrocarbonylation of halophenols

correspondents.

  US Pat. No. 3,960,932 describes a general process for preparing aldehydes by reaction of aryl halides, vinyl or heterocyclic compounds with a mixture of carbon monoxide and hydrogen in the presence of an amine. tertiary and a palladium catalyst consisting of a complex of a divalent palladium derivative with a phosphine, a phosphite or an arsine or in the combination of a divalent palladium salt or a finely divided palladium metal with a complexing agent from the group of phosphines, phosphites or arsines. The aryl halides used in the process according to US 3,960,932 are phenyl or naphthyl bromides or iodides, unsubstituted or substituted by

  alkyl, alkoxy, nitrile or alkyl carboxylate groups.

  European Patent EP 109 606 proposes to increase the kinetics of the hydrocarbonylation reaction of the preceding process, operating at pressures of 2 to 40 MPa (20 to 400 bar), at temperatures of 80 ° C. to 250 ° C. and using significant quantities of phosphine or

  phosphite (2 to 10 times the molar amount of catalyst).

  It should be noted that these methods of the prior art do not

  do not apply to the hydrocarbonylation of halophenols.

  It is precisely an object of the present invention to provide a process for the preparation of hydroxybenzaldehydes by reaction of a halophenol with a carbon monoxide / hydrogen mixture in the presence of a tertiary amine, a catalyst and a catalyst. a noble metal and a phosphine. More particularly, it is a process for the preparation of a hydroxybenzaldehyde of the general formula (I) HO - t - (Z) n (I) CHO - 2 in which - n represents 0, 1 or 2 - Z represents an electron-donor group or an electron-withdrawing group by reacting a halophenol of general formula (II) HO X (Z) n (II) X in which X represents a bromine atom or an iodine atom - Z a the meanings indicated above; n represents 0, 1 or 2; with a carbon monoxide / hydrogen mixture, in the presence of a noble metal catalyst, a tertiary amine and triphenylphosphine, characterized in that the tertiary amine is such that the pKa of its conjugated acid is , on the one hand less than or equal to the pKa of the halophenol of

  formula (II) and, on the other hand, higher than that of triphenylphosphine.

  The pKa in water (usually at 25 ° C.) of the conjugated acid of the tertiary amine is indicated in tables found in the literature.

  The pKa in the water of triphenylphosphine is 2.73 (at 25 ° C.).

  The pKa of the halophenol of formula (II) is determined according to the IUPAC method E3bg entitled "IONIZATION CONSTANTS OF ORGANIC ACIDS IN

  AQUEOUS SOLUTIONS "(publisher Pergamon Press, 1979).

  It has therefore been found that in order to be able to hydrocarbonylate a halophenol of formula (II) in order to prepare a hydroxybenzaldehyde of formula (I), the pKa of the conjugated acid of the tertiary amine used must be between that of the triphenylphosphine used and that of

  halophenol (II) used.

  When the tertiary amine used does not meet this condition, there is essentially formation of a polymeric compound, but

  virtually no hydroxybenzaldehyde.

  The halogenophenols of formula (II) to which the present invention applies are more particularly those for which the symbol Z represents a hydroxyl radical, an alkyl radical, an alkoxy radical, an alkyl or alkoxy radical substituted by one or more atoms. of chlorine or fluorine, a cycloalkyl radical, a phenyl radical, a cycloalkoxy radical, a phenoxy radical, an alkoxycarbonyl radical, a cycloalkoxycarbonyl radical, a phenoxycarbonyl radical, an alkylcarbonyloxy radical, a cycloalkylcarbonyloxy radical or a phenylcarbonyloxy radical, one of the radicals substituted by one or more fluorine and / or chlorine atoms or nitrile groups and the symbol

  X represents a bromine atom or an iodine atom.

  More particularly in the formulas (I) and (II), - X represents a bromine atom, - Z represents: a hydroxyl radical; a linear or branched alkyl radical of 1 to 20 carbon atoms or an alkyl radical substituted with one or more fluorine and / or chlorine atoms, such as, for example, methyl, ethyl, propyl, butyl, pentyl, hexyl or octyl radicals; decyl, trifluoromethyl, difluorochloromethyl, trichloromethyl; preferably a lower alkyl radical, that is to say having 1 to 4 carbon atoms or a lower alkyl radical substituted with 1 to 3 fluorine atoms and / or chlorine; a linear or branched alkoxy radical having 1 to 20 carbon atoms or an alkoxy radical substituted with one or more atones of fluorine and / or chlorine; preferably a lower alkoxy radical (having 1 to 4 carbon atoms) or a lower alkoxy radical substituted with 1 to 3 fluorine and / or chlorine atoms, such as, for example, the methoxy, ethoxy, isopropoxy, difluorochloromethoxy or trichloromethoxy radicals; a cyclopentyl, cyclohexyl or cyclooctyl radical; a phenyl radical or a phenyl radical substituted with 1 to 3 alkyl or lower alkoxy radicals, such as the 4-xylyl, toluyl, methoxyphenyl and ethoxyphenyl radicals; an alkoxycarbonyl radical having 2 to 11 carbon atoms and preferably 2 to 5 carbon atoms such as, for example, the methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl and butoxycarbonyl radicals; an alkoxycarbonylalkyl radical whose alkoxycarbonyl part is as defined above and the alkyl part has 1 to 4 carbon atoms; A cyclopentyloxycarbonyl or cyclohexyloxycarbonyl radical; a phenoxycarbonyl or methylphenoxycarbonyl radical; an alkylcarbonyloxy radical having 2 to 11 carbon atoms and preferably 2 to 5 carbon atoms, such as, for example, the acetoxy, propionyloxy and butyryloxy radicals; unradical cyclopentanoyloxy or cyclohexanoyloxy; a benzoyloxy, methylbenzoyloxy or dimethylbenzoyloxy radical. As specific examples of hydroxybenzaldehydes of formula (I) that can be obtained by the process according to the invention, mention may be made in a nonlimiting manner of 4-hydroxybenzaldehyde, 2-hydroxybenzaldehyde, vanillin (or 4-hydroxy-3-methoxy benzaldehyde), 2-hydroxy-5-methoxybenzaldehyde, 2-hydroxy-3-methoxybenzaldehyde, 4-hydroxy-3-ethoxybenzaldehyde, 2-hydroxy-3-ethoxybenzaldehyde, 2-hydroxy-5-ethoxybenzaldehyde, 3,5-dimethoxy-4-hydroxybenzaldehyde, 3,4-dihydroxy

  benzaldehyde, 2,5-dihydroxybenzaldehyde, 2,3-dihydroxybenzaldehyde.

  As specific examples of halogenophenols of formula (II) that can be used in the process according to the invention, there may be mentioned, without limitation, 4-bromo phenol, 2-bromo phenol, 4-bromo-methoxy 2-phenol, 2-bromo-4-methoxyphenol, 6-bromo-2-methoxyphenol, 4-bromo-2-ethoxyphenol, 2-bromo-4-ethoxyphenol, bromo- 6-ethoxy-2-phenol, bromo -4-dimethoxy-2,6-phenol, bromo-4-dihydroxy-1,2 benzene,

  2-bromo-1,4-dihydroxybenzene, 3-bromo-1,2-dihydroxybenzene.

  As catalysts, it is possible to use, for carrying out the process according to the invention, a finely divided noble metal of group VIII of the periodic table of elements such as palladium,

  rhodium and iridium, or their salts of mineral or organic acids.

  Palladium derivatives are particularly suitable

to the process of the invention.

  As specific examples of palladium derivatives, mention may be made of carboxylates such as in particular acetates, propionates, butyrates or

  benzoates of palladium (II), palladium chloride.

  It is also possible to use complexes of mineral salts or

  organic palladium with triphenylphosphine.

  In the latter case, this complex is generally carried out in situ between the palladium derivative and the triphenylphosphine present. However, it is also possible to prepare said complex extemporaneously and introduce it into the reaction medium. We can then add or not a quantity

  additional free triphenylphosphine.

  The amount of catalyst expressed in moles of metal atoms or in moles of metal derivative per mole of halogenophenol of formula (I) can

vary within wide limits.

  Thus, it can be between 10 and 10 mol / mol and

  preferably between 10-4 and 10-2 mol / mol.

  The amount of free triphenylphosphine and / or in the form of a complex with the catalyst is such that the molar ratio

  triphenylphosphine / noble metal catalyst is at least equal to 2.

  The triphenylphosphine / noble metal ratio can reach

values as high as 10,000.

  A triphenylphosphine / noble metal ratio of between 4 and

  1,000 is generally very suitable.

  The tertiary amine used in the present process may be an amine of the general formula (III)

N - (R1) 3 (III)

  in which the radicals R1, which are identical or different, represent hydrocarbon radicals having 1 to 20 carbon atoms, such as

  alkyl, cycloalkyl or aryl radicals.

  More particularly, the symbols R represent an alkyl radical having 1 to 10 carbon atoms and preferably 1 to 4 carbon atoms.

  carbon or a cyclopentyl or cyclohexyl radical.

  As examples of such amines, mention may be made of

  triethylamine, tri-n-propylamine, tri-n-butylamine, methyldibuty-

  amine, methyldicyclohexylamine, ethyldiisopropylamine, N, N-diethylcyclohexylamine. The tertiary amine may also be a heterocyclic tertiary amine such as, for example, pyridine, betapicoline, alpha-picoline, gamma-picoline, 2,6-dimethylpyridine, 3,4-dimethylpyridine, dimethyl -2,4 pyridine, pyridazine, quinoline, isoquinoline, phthalazine, 1,8-naphthyridine,

  quinoxaline, quinazoline, cinnoline, pteridine.

  When using a halophenol such as 4-bromo phenol, 4-bromo-2-methoxyphenol or 4-bromo-2-ethoxyphenol which lead to very important hydroxybenzaldehydes and whose pKa (C) is from 9.5 for 4-bromo phenol and 4-bromo-2-methoxyphenol, and close to this value for 4-bromo-2-ethoxyphenol, heterocyclic tertiary amines are generally well suited. In fact the pKa of their conjugated acid is most often less than 9.5, whereas the tertiary amines of formula (III) such as triethylamine which have a pKa of their conjugated acid higher than 9.5, can not be

  used. They lead essentially to polymeric compounds.

  The amount of tertiary amine used must be sufficient to

  neutralize the hydracid released by the reaction.

  In addition, the concentration of tertiary amine in the medium must

  be at least 2 moles per liter for the duration of the reaction.

  There is no critical upper limit for the amount of tertiary amine, which can therefore be used in large excess over the

  quantity theoretically necessary for the neutralization of the hydracid formed.

  In order to maintain the tertiary amine concentration, at least equal to the limit values indicated above, throughout the duration of the reaction, the amount of amine employed must be calculated in such a way

  at the end of the reaction, the concentration is at least equal to these values.

  An additional quantity of tertiary amine can also be added as the reaction progresses, in order to compensate for the

  amount of amine consumed by the neutralization of the hydracid.

  It is possible to use CO / H 2 mixtures having different molar ratios of the two gases. Generally, the CO / H2 molar ratio

varies between 0.1 and 10.

  The pressure under which the process is carried out also varies very widely. Generally, it ranges from 0.1 to 30 MPa (1 & 300 bar)

  and preferably from 1 to 15 MPa (10 to 150 bar).

  The process according to the invention is carried out in the liquid phase.

  An inert solvent can be used under the conditions of the hydrocarbonylation reaction. Thus, one can use saturated aliphatic or cycloaliphatic hydrocarbons such as hexane or cyclohexane, or aromatics such as benzene, toluene, xylenes; esters such as methyl benzoate, methyl terephthalate, methyl adipate, dibutyl phthalate; esters or ethers of polyols such as tetraethylene glycol diacetate; ethers

  such as tetrahydrofuran or dioxane.

  The concentration of the halophenol of formula (I) used in the solvent may vary within very wide limits, until saturation under the operating conditions. Generally, it is not

  economically interesting to use less than 5% by weight of halogen

by volume of solvent.

  In general, the concentration by weight of halophenol per volume of solvent is between 5% and 50% and preferably between

10% and 40%.

  In practice, the process according to the invention can be carried out by introducing into an inert autoclave the halophenol of formula (I), the tertiary amine, the catalyst, triphenylphosphine and the solvent, then, after the usual purges, feeding the autoclave with adequate pressure of a CO / H2 mixture; the contents of the autoclave are then stirred with the proper temperature until the absorption ceases. The pressure in the autoclave can be kept constant for the duration of the reaction thanks to a reserve of mixture

  gas, which feeds it to the chosen pressure.

  26z81o2 At the end of the test, the autoclave is cooled and degassed. The mixture

The reaction is recovered.

  A very simple way of treatment is to add to the mix

  Reaction an aqueous solution of alkali metal hydroxide.

  After stirring and decantation, an aqueous phase and an organic phase are thus obtained. The organic phase essentially contains the catalyst, triphenylphosphine and at least a portion of the tertiary amine. This organic solution can easily be recycled in a new hydrocarbonylation reaction, after adding a new charge

  halophenol and a possible tertiary amine supplement.

  The aqueous phase essentially contains hydroxybenzaldehyde

  formed in the form of the alkali metal phenate, as well as any

  products and optionally unconverted halophenol, also

  form of alkali metal derivatives.

  A simple acidification and either a crystallization when the product is solid or a distillation when the product is liquid,

  allow the recovery of pure hydroxybenzaldehyde.

  The process can be carried out batchwise or continuously as indicated above by recycling the catalyst,

  triphenylphosphine and tertiary amine.

  The following examples illustrate the invention.

  Examples 1 to 6 and Comparative Trials A and B In a 125 cm autoclave made of HASTELLOY B2 brand alloy, equipped with a heating device and stirring, are charged: 10.15 g (50 mmol) of 4-bromo-2-methoxyphenol - 0.22 g (1 mmol) of palladium diacetate - 1.51 g (5 mmol) of triphenylphosphine - 110 mmol of tertiary amine (shown in the table below)

17.5 cm of toluene.

  The autoclave is closed and purged with the help of a mixture

equimolecular CO and H2.

  Subsequently, 0.1 MPa (1 bar) of pressure of this CO / H 2 mixture is charged and the contents of the autoclave are heated to 100 ° C.; we adjust the

  pressure CO / H2 & 3 MPa (30 bar), then the temperature is raised to 150 C.

  The temperature is maintained at 150 ° C. and the pressure at 3 MPa

  until the end of absorption of the CO / H2 mixture.

  The autoclave is then cooled, degassed.

  After taking a sample for determination by liquid chromatography, 40 cm 3 of an aqueous solution of sodium hydroxide (6 g of sodium hydroxide) are added to the reaction mixture and the autoclave is stirred at room temperature.

  room temperature for 1 hour.

  The aqueous phase is separated by decantation, acidified with HCl

  to pH 1 and extracted with 3 times 100 cm3 of ethyl ether.

  The ethereal solution obtained is treated with 2 times 50 cm of a

  20% aqueous sodium hydrogencarbonate solution.

  The ether solution is then decanted and the ether is evaporated.

  The brown solid obtained is recrystallized in toluene, then

  in water to lead to pure vanillin.

  The table below gives for each test the indications concerning the tertiary amine used, the duration, the reaction rate -i expressed in MPa.h, the conversion rate (TT%) of 4-bromo-2-methoxyphenol ( BMPH), the yield (RT%) of 4-hydroxy-3-methoxybenzaldehyde (vanillin) (HMBZ) relative to 4-bromo-2-methoxy-phenol converted, the RT in guaiacol and optionally in 4-hydroxy-3-methoxy benzoic acid. The difference to 100% of the sum of the RTs indicated above corresponds to the formation of a polymeric compound of structure HOO -O n <"cO // 0QH3_

L n '-.

  n being equal to or greater than 1 and R representing CHO, H or Br.

262810 2

- 10 -

  It is noted that: - when the pKa of the conjugated acid of the tertiary amine is greater than that of the 4-bromo-2-methoxyphenol used, there is no formation of aldehyde (test A) - when the pKa of the conjugated acid of the tertiary amine is lower than that of triphenylphosphine, the yield of aldehyde is very low (test B) - when the pKa of the conjugated acid of the tertiary amine is substantially equal to that of 4-bromo-2-methoxyphenol, the

  yield of aldehyde is low (Example 6).

  Tests Amine pKa * Duration Speed TT% RT% RT% RT% tertiary MPa.h-1 BMPH ** HMBZ ** guaiacol HMBQ ** Example 1 Pyridine 5.25 2 h 50 0.9 98 26 20 3.2 Gamma Example 2 Picoline 6.02 2 h 20 1.2 99 35 17 5.7 3,4-Dimethyl Example 3 Pyridine 6.57 2 h 05 1.4 100 31 6.8 2,3 Dimethyl-2 Example 4 Pyridine 6.73 4 hours 0.63 100 28 4.0 8.1 2,4-Dimethyl Example 5 Pyridine 6.99 2h 55 1.3 100 46 9.0 5.7 Dimethylamino-4 Example 6 Pyridine 9.5 18 min 7.5 100 8.0 1.5 0.2 Comparative Triethyl Assay A Amine 11.1 20 min 100 0 0 0 Comparative Test B Pyrazine 0.65 6 h 25 0.3 88 5.9 14.0 4.1 * tertiary amine conjugated acid pka ** BMPH = 4-bromo-2-methoxyphenol HMBZ = 4-hydroxy-3-methoxybenzaldehyde (vanillin) HMBQ = 4-hydroxy-methoxy acid -3 benzoic

2628 102

- 12 -

Claims (17)

  A process for preparing a hydroxybenzaldehyde of the general formula (I): HO - - (Z) n (I) xi CHO   in which - n represents 0, 1 or 2 - Z represents an electron-donor group or an electron-withdrawing group by reaction of a halophenol of general formula (II) HO _... t-- (Z) n ( II) X in which - X represents a bromine atom or an iodine atom; Z has the meanings indicated above; n represents 0, 1 or 2; with a carbon monoxide / hydrogen mixture, in the presence of a catalyst based on a noble metal, a tertiary amine and triphenylphosphine, characterized in that the tertiary amine is such that the pKa of its conjugated acid is , on the one hand less than or equal to the pKa of the halophenol of   formula (II) and, on the other hand, higher than that of triphenylphosphine. 2 28 1 0 2 - 13 -   2. Process according to claim 1, characterized in that a halophenol of formula (II) is used in which - the symbol Z represents a hydroxyl radical, an alkyl radical, an alkoxy radical, an alkyl or alkoxy radical substituted by one or more chlorine or fluorine atoms, a cycloalkyl radical, a phenyl radical, a cycloalkoxy radical, a phenoxy radical, an alkoxycarbonyl radical, a cycloalkoxycarbonyl radical, a phenoxycarbonyl radical, an alkylcarbonyloxy radical, a cycloalkylcarbonyloxy radical or a phenylcarbonyloxy radical; one of the preceding radicals substituted by one or more fluorine atoms and / or chlorine or nitrile groups;   the symbol X represents a bromine atom or an iodine atom.   3. Method according to one of claims 1 or 2, characterized in   a halophenol of formula (II) in which - X represents a bromine atom, - Z represents: a hydroxyl radical; a linear or branched alkyl radical of 1 to 20 carbon atoms or a 41 alkyl radical substituted with one or more fluorine and / or chlorine atoms, such as, for example, methyl, ethyl, propyl, butyl, pentyl, hexyl or octyl radicals; decyl, trifluoromethyl, difluorochloromethyl, trichloromethyl; preferably a lower alkyl radical, that is to say having 1 to 4 carbon atoms or a lower alkyl radical substituted with 1 to 3 fluorine atoms and / or chlorine; a linear or branched alkoxy radical having 1 to 20 carbon atoms or an alkoxy radical substituted with one or more fluorine and / or chlorine atoms; preferably a lower alkoxy radical (having 1 to 4 carbon atoms) or a lower alkoxy radical substituted with 1 to 3 fluorine and / or chlorine atoms; as for example the methoxy, ethoxy, isopropoxy, difluorochloromethoxy or trichloromethoxy radicals; 26 28 1 0 2 - 14 -   a cyclopentyl, cyclohexyl or cyclooctyl radical; a phenyl radical or a phenyl radical substituted with 1 to 3 alkyl or lower alkoxy radicals, such as the xylyl, toluyl, methoxyphenyl and os05 ethoxyphenyl radicals; an alkoxycarbonyl radical having 2 to 11 carbon atoms and preferably 2 to 5 carbon atoms such as, for example, the methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl and butoxycarbonyl radicals; An alkoxycarbonylalkyl radical whose alkoxycarbonyl part is as defined above and the alkyl part has 1 to 4 carbon atoms; a cyclopentyloxycarbonyl or cyclohexyloxycarbonyl radical; 15. a phenoxycarbonyl or methylphenoxycarbonyl radical; an alkylcarbonyloxy radical having 2 to 11 carbon atoms and preferably 2 to 5 carbon atoms, such as, for example, acetoxy, propionyloxy or butyryloxy radicals, a cyclopentanoyloxy or cyclohexanoyloxy radical; 20. a benzoyloxy, methylbenzoyloxy or dimethylbenzoyloxy radical.   4. Method according to one of claims 1 to 3, characterized in   the halophenol of formula (II) is 4-bromo phenol, 2-bromo phenol, 4-bromo-2-methoxyphenol, 2-bromo-4-methoxyphenol, 6-bromo-2-methoxyphenol, 4-bromo-2-ethoxyphenol, 2-bromo-4-ethoxyphenol, 6-bromo-2-ethoxyphenol, 4-bromo-2,6-dimethoxyphenol, 4-bromo-1,2-dihydroxybenzene, the bromo-2-dihydroxy-1,4 benzene, bromo3 1,2-dihydroxybenzene.   5. Method according to one of claims 1 to 4, characterized in   the catalyst used is a finely divided noble metal of Group VIII of the Periodic Table of Elements such as palladium,   rhodium and iridium, or their salts of mineral or organic acids. - 15 -   6. Method according to one of claims 1 to 5, characterized in   the catalyst used is chosen from palladium derivatives such as carboxylates, especially acetates, propionates, butyrates or   benzoates of palladium (II), and palladium chloride.   7. Method according to one of claims 1 & 6, characterized in   the amount of catalyst, expressed in moles of metal atoms or in moles of metal derivative per mole of halophenol of formula (I), is between 10-5 and 1 mole / mole and preferably between 10-4 and 10 2 mole / mole.   8. Method according to one of claims 1 & 7, characterized in   what the amount of free triphenylphosphine and / or in the form of complex   with the catalyst, is such that the molar ratio triphenyl-   phosphine / noble metal catalyst is between 2 and 10,000, and   preferably between 4 and 1,000.   9. Method according to one of claims 1 & 8, characterized in   that the tertiary amine used is an amine of the general formula (III) N - (R1) 3 (III)   in which the radicals R1, which are identical or different, represent hydrocarbon radicals having from 1 to 20 carbon atoms, such as   alkyl, cycloalkyl or aryl radicals.   10. Process according to Claim 9, characterized in that the tertiary amine used is an amine of general formula (III) in which the symbols R 1 represent an alkyl radical having 1 to 10 carbon atoms and preferably 1 to 4 carbon atoms. carbon or a radical cyclopentyl or cyclohexyl.   11. Method according to one of claims 1 to 8, characterized in   the tertiary amine used is a heterocyclic amine. - 16 -   12. Process according to claim 11, characterized in that the heterocyclic amine is pyridine, beta-picoline, alpha-picoline, gamma-picoline, 2,6-dimethylpyridine, 3,4-dimethyl pyridine, 2,4-dimethylpyridine, pyridazine, quinoline, isoquinoline, phthalazine, 1,8-naphthyridine, quinoxaline, quinazoline, cinnoline, pteridine.   13. Method according to one of claims 1 & 12, characterized in that the amount of tertiary amine is sufficient to neutralize the hydracid released by the reaction and that preferably the concentration of tertiary amine in the medium is at less equal to   2 moles per liter for the duration of the reaction.   14. Process according to one of Claims 1 to 13, characterized in   the pressure used is between 0.1 to 30 MPa (1 to 300 bar)   and preferably between 1 to 15 MPa (10 to 150 bar).   15. Method according to one of claims 1 to 14, characterized in   it is conducted in an inert solvent under the conditions of the hydrocarbonylation reaction selected from saturated aliphatic or cycloaliphatic hydrocarbons such as hexane or cyclohexane, or aromatics such as benzene, toluene, xylenes; esters such as methyl benzoate, methyl terephthalate, methyl adipate, dibutyl phthalate; esters or ethers of polyols such as tetraethylene glycol diacetate; cyclic ethers such as tetrahydrofuran or dioxane.   16. Method according to one of claims 1 to 15, characterized in   the concentration of the halophenol of formula (I) used, expressed by weight of halophenol per volume of solvent, is included   between 5% and 50% and preferably between 10% and 40%.   17. Method according to one of claims 1 to 16, characterized in   at the end of the test, the reaction mixture is treated with a solution   aqueous alkali metal hydroxide.