Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
  • C08G63/78—Preparation processes
  • C08G63/81—Preparation processes using solvents
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
  • C08G63/78—Preparation processes
  • C08G63/82—Preparation processes characterised by the catalyst used
  • C08G63/823—Preparation processes characterised by the catalyst used for the preparation of polylactones or polylactides
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
  • C08G63/78—Preparation processes
  • C08G63/82—Preparation processes characterised by the catalyst used
  • C08G63/87—Non-metals or inter-compounds thereof

Definitions

• the present invention relates to a process for synthesizing polyesters under mild conditions using ionic liquids or mixtures of ionic liquids acting both as solvents and as catalysts.
• Polyesters are versatile, biodegradable and / or recyclable thermoplastics which are rapidly developing for environmental applications, such as compostable aliphatic or aliphatic-aromatic polyesters, or for biomedical applications, such as copolymers of lactide, glycolide, p-dioxanone or caprolactone.
• the polyesters can be obtained by three major synthetic routes [(Fradet, A. Tessier, M. Polyesters., In Synthetic methods in step-growth polymers, ME Rogers and Long TE, Eds., New York, J. Wiley & Sounds: 17-132 (2003)]:
• Ionic liquids are generally defined as organic salts having a melting point below the boiling point of water [Wasserscheid, P .; Welton, T., Ionic Liquids in Synthesis, 2nd edition. Wiley-VCH, Weinheim:
• the cations are usually bulky and have low symmetry. The most used have a structure of the ammonium, imidazolium, pyridinium, pyrrolidinium, phosphonium type. Imidazolium is the cation most frequently represented in publications, especially N, N'-dialkylimidazolium cations which have interesting physico-chemical properties, in particular a low melting temperature.
• Anions are simple anions, for example halides, or polynuclear anions.
• Polynuclear anions with "Lewis acid” character First generation LI Al 2 Cl 7 “ , Al 3 CIi 0 " , Au 2 Cl 7 “ , Fe 2 Cl 7 “ , ...), very sensitive to water and not very stable to ambient air were replaced in second-generation LIs with much more stable anions, such as bis ((trifluoromethyl) sulfonyl) imidate [Tf 2 N " ], bis (methylsulfonyl) imidate [(MeS) 2 N “ ], dicyanamide [N ( CN) 2 “ ], hexafluorophosphate (mp 6 " ) [Mac Farlane, D. R et al, Chem. Common, 2001, 1430].
• Ionic liquids have proved particularly interesting for four types of reactions: i) nucleophilic substitutions, ii) reactions under acid catalysis or Friedel-Crafts, iii) reactions carried out at high temperature (reactions of rearrangements, Diels-Alder , from Heck) and iv) oxidation and epoxy dations.
• the advantage provided by the use of LI is to allow easier separation and recycling of the catalyst, to remove potentially toxic metal catalyst residues from the polymer and in some cases to obtain polymerization rates. and higher molar masses.
• the main methods for synthesizing polyesters have either the disadvantage of using volatile organic solvents and reagents generating a harmful release of hydrochloric acid (case of acid chlorides) or of requiring the use of high temperatures which are not always compatible with the nature of the polyesters to be synthesized.
• the inventors have therefore set themselves the goal of providing a process for synthesizing polyesters that is simple and quick to implement, under mild conditions that do not generate harmful release of hydrochloric acid while taking place at temperatures lower than those usually used in the prior art and without the use of a metal catalyst.
• polyesters having a mass average molecular weight Mw> 10,000 can be carried out by direct polyesterification in ionic liquids, the Pennion or the cation or both having an acidic character of Bronsted, at a much lower temperature and during reaction times much shorter than those required for the preparation of polyesters by conventional methods, in bulk or in solution.
• the subject of the present invention is therefore a process for the synthesis of polyesters or copolyesters having a mass average molecular weight M w of greater than 10,000, the said molar mass being measured by steric exclusion chromatography:
• polyesterification reaction between at least a first monomer or oligomer selected from compounds carrying at least 2 carboxylic acid functions, compounds carrying at least two carboxylic acid ester functions, compounds carrying at least one carboxylic acid function and at least one at least one hydroxyl function, the compounds carrying at least one carboxylic acid ester function and at least one hydroxyl function and at least one second monomer or oligomer chosen from compounds bearing at least two hydroxyl functions, or
• polyesterification reaction of a single monomer or oligomer selected from compounds carrying at least one carboxylic acid function and at least one at least one hydroxyl function and the compounds carrying at least one carboxylic acid ester function and at least one hydroxyl function;
• said method being characterized in that said polyesterification reaction is carried out at a temperature of 60 to 150 ° C., at atmospheric pressure or under vacuum, in a reaction medium free of metal catalyst and comprising at least one acid ionic liquid consisting of a anion and a cation whose electric charges equilibrate and wherein at least the cation is a strong acid in the Bronsted sense or comprises a group which is a strong acid in the Bronsted sense.
• strong acid in the Bronsted sense is understood to mean any chemical species capable of yielding one or more H + protons.
• the present invention allows the synthesis of polyesters under mild conditions and at moderate temperature.
• the synthesis method according to the present invention makes it possible to considerably reduce the temperature and the duration of the reactions and to easily recycle the solvent-catalyst.
• the reduction of the reaction temperatures further allows the direct synthesis of functional polyesters having thermally fragile units having, for example, a biological activity.
• polyesterification reactions used in the present invention are condensation reactions (1) between carboxylic acid type groups and alcohol type groups, and / or (2) between ester type groups. carboxylic acid and alcohol and / or (3) groups between carboxylic acid groups and carboxylic acid ester groups. These reactions are well known to those skilled in the art to lead to polyesters and are written respectively:
• R and R ' independently of each other, represent any type of monomeric, oligomeric or polymer molecule that can lead to a higher molecular weight polymer molecule
• R 1 is an alkyl group, preferably a methyl, ethyl, propyl, isopropyl, butyl or isobutyl group and - R 2 is an alkyl group, preferably a methyl or ethyl group.
• the compounds reacted to carry out the polyesterification reaction carry either one or more groups of type A and are chosen from compounds of type A x having the following formula I (A) x R 3 , one or more groups of type B and are selected from compounds of type B x having the following formula II (B) y R 4 , one or more groups of type A and one or more groups of type B and are selected from the A x B y type compounds having the following formula III (A) x R 5 (B) y, formulas I, II and III wherein:
• x and y are integers greater than or equal to 1 and
• the groups R 3 , R 4 and R 5 are aliphatic, cycloaliphatic, aromatic or mixed groups, optionally containing heteroatoms or non-reactive groups under the synthetic conditions used, for example ketone groups; , sulfone, amide, imine.
• polyesters obtained according to the process of the invention have a linear or branched architecture, optionally crosslinked.
• the stoichiometric ratio between the mutually reactive groups can be adjusted to obtain either a polymer of high molecular weight, either an oligomer carrying reactive end groups, a branched polymer or a crosslinked polymer.
• the compounds reacted to carry out the polyesterification reaction contain either two type A groups (type A 2 compounds) or two type B groups (type compounds).
• B 2 a group of type A and a group of type B (compounds of type AB) and the polyester or copolyester obtained has a linear architecture.
• the esterification reaction is carried out by reacting either one or more compounds containing a single group of type A and several groups of type B (compounds of type AB x ) with optionally a compound containing more than one type B group, one or more compounds containing more than one type A group and a single type B group (type A x B compounds) with possibly a compound containing more than one type A group which leads to polymers (polyesters or copolyesters) having a highly branched architecture, called hyperbranched or hyperbranched.
• the composition of the medium is adjusted between compounds containing several groups of types A and / or several groups of type B according to calculations known to those skilled in the art for to obtain a crosslinked, insoluble and infusible polymer.
• one or more of the compounds reacted are oligomers, for example polyesters, polyethers, polyamides, polyimines, bearing reactive groups of type A and / or or B.
• oligomers for example polyesters, polyethers, polyamides, polyimines, bearing reactive groups of type A and / or or B.
• the resulting polyesters then contain different types of polymer blocks and are generally referred to as block copolymers.
• X n + cations mention may notably be made of ammoniums, imidazoliums, pyridiniums, pyrrolidiniums, piperidiniums, triazoliums, mo ⁇ holiniums and phosphoniums of general formulas X1 to X8, as follows:
• the term "mixed group” means a group consisting of parts of different types, namely aliphatic and / or cycloaliphatic and / or aromatic.
• the ionic liquid is chosen from 3- (3-alkyl-1-imidazole) -1-propanesulfonic acid and 4- (3-alkyl-1-imidazole) -l- butanesulfonic compounds of formula (IV) below:
• Y is chosen from the anions Y q ' as defined above and R 26 is an aliphatic group, a cycloaliphatic group, an aromatic group or a mixed group, said groups optionally containing one or more heteroatoms.
• the ionic liquids of formula (IV) above are preferably chosen from hydrogen sulphates, trifluoromethanesulphonates, tosylates, dihydrogenphosphates and bis (trifluoromethylsulphonyl) imidates of the acids:
• the ionic liquid acid can constitute by itself the reaction medium.
• the reaction medium may consist of a single acidic ionic liquid or a mixture of two or more acidic ionic liquids as defined according to the invention.
• the reaction medium may also comprise at least one nonacidic ionic liquid.
• nonacidic ionic liquids mention may be made, by way of non-limiting example, of 1-butyl-3-methylimidazolium chloride, 1-butyl-3-methylimidazolium tetrafluoroborate and bis (trifluoromethylsulfonyl) imidate. butyl-3-methylimidazolium.
• the compounds reacted to carry out the polyesterification reaction are present in the reaction medium in an amount such that the mass proportion of the final polymer is between 1 and 99%, preferably between 10 and 70% relative to the total mass of the reaction medium.
• the temperature of the reaction medium is preferably from approximately 80 to 120 ° C. at atmospheric pressure.
• a stream of inert gas (nitrogen or argon, for example) is introduced above or into the reaction medium during the polyesterification reaction. This facilitates the removal of the reaction by-product (water, alcohol, acid) and thus promotes the production of a high molecular weight polyester.
• a vacuum of 0.1 to 100 mbar is applied above the reaction medium during the polyesterification reaction. This facilitates the removal of the reaction by-product (water, alcohol, acid) and thus promotes the production of a high molecular weight polyester.
• the duration of the polyesterification reaction can vary from 1 minute to 48 hours and depends on the temperature used, an increase in temperature resulting in a decrease in the time required to obtain a polymer having the desired molar mass.
• the polyesterification reaction is carried out for 30 min at about 110 ° C.
• the reaction medium is allowed to return to ambient temperature and the polymer can be recovered by separation techniques well known to those skilled in the art, such as, for example, by filtration if the polymer precipitates. at room temperature.
• the polymer If the polymer is soluble in the reaction medium at room temperature, it can be recovered by precipitation in a non-solvent of the polymer, for example water, methanol, ethanol or isopropanol or by extraction with a solvent of polymer, for example chloroform or toluene.
• a non-solvent of the polymer for example water, methanol, ethanol or isopropanol
• a solvent of polymer for example chloroform or toluene.
• the acidic ionic liquid can then be used for a new reaction, after evaporation of the non-solvent or solvent if it has been added.
• the present invention is illustrated by the following exemplary embodiments, to which it is however not limited.
• Mw is mass average molar mass and was measured by size exclusion chromatography (CH 2 Cl 2 , 1 mL / min, Phenomenex ® columns (Phenogel 10 5 , 10 4 , 10 3 , 500, 100A ), refractometric detection, polystyrene calibration).
• [BIm4S] .HSO 4 were introduced into a proscotted tube, provided with an inlet and a nitrogen outlet and a magnetic bar type cruciform head 2 sides. The mixture was stirred for 1 hour at 110 ° C. under a nitrogen flow rate of 500 ml / min. 10 ml of propan-2-ol was added to the reaction medium which was then heated at 85 ° C for 5 minutes. After cooling with stirring, a white precipitate was obtained. After filtration and drying under vacuum, 265 mg of a white solid were recovered.

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• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Polyesters Or Polycarbonates (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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• 2009
  • 2009-07-31 FR FR0955403A patent/FR2948671B1/fr not_active Expired - Fee Related
• 2010
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  • 2010-07-28 EP EP10752891A patent/EP2459615A1/fr not_active Withdrawn
  • 2010-07-28 WO PCT/FR2010/051605 patent/WO2011012814A1/fr not_active Ceased
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  • 2010-07-28 CN CN2010800388534A patent/CN102725328A/zh active Pending

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