Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C41/00—Preparation of ethers; Preparation of compounds having groups, groups or groups
  • C07C41/48—Preparation of compounds having groups
  • C07C41/50—Preparation of compounds having groups by reactions producing groups
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J11/00—Recovery or working-up of waste materials
  • C08J11/04—Recovery or working-up of waste materials of polymers
  • C08J11/10—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation
  • C08J11/18—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation by treatment with organic material
  • C08J11/22—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation by treatment with organic material by treatment with organic oxygen-containing compounds
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
  • C07C29/09—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by hydrolysis
  • C07C29/10—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by hydrolysis of ethers, including cyclic ethers, e.g. oxiranes
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C43/00—Ethers; Compounds having groups, groups or groups
  • C07C43/30—Compounds having groups
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C45/00—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds
  • C07C45/27—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
  • C07C51/16—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation
• • 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
  • C08G2/00—Addition polymers of aldehydes or cyclic oligomers thereof or of ketones; Addition copolymers thereof with less than 50 molar percent of other substances
  • C08G2/08—Polymerisation of formaldehyde
• • 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
  • C08G2/00—Addition polymers of aldehydes or cyclic oligomers thereof or of ketones; Addition copolymers thereof with less than 50 molar percent of other substances
  • C08G2/18—Copolymerisation of aldehydes or ketones
  • C08G2/24—Copolymerisation of aldehydes or ketones with acetals
• • 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
  • C08G2/00—Addition polymers of aldehydes or cyclic oligomers thereof or of ketones; Addition copolymers thereof with less than 50 molar percent of other substances
  • C08G2/30—Chemical modification by after-treatment
  • C08G2/36—Chemical modification by after-treatment by depolymerisation
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2359/00—Characterised by the use of polyacetals containing polyoxymethylene sequences only
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2359/00—Characterised by the use of polyacetals containing polyoxymethylene sequences only
  • C08J2359/02—Copolyoxymethylenes
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2471/00—Characterised by the use of polyethers obtained by reactions forming an ether link in the main chain; Derivatives of such polymers
  • C08J2471/02—Polyalkylene oxides
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
  • Y02W30/00—Technologies for solid waste management
  • Y02W30/50—Reuse, recycling or recovery technologies
  • Y02W30/62—Plastics recycling; Rubber recycling

Definitions

• the present invention relates to a process for recycling polyacetal for obtaining polyoxymethylenedialkylethers as well as the use of these polyoxymethylenedialkylethers for the preparation of acid or ester (meth) acrylic, (meth) acrolein or neopentylglycol .
• POM polyoxymethylene
• POMs can be reused in injection molding processes, but the implementation of these processes is limited by a degradation of the materials and the release of formaldehyde, which is harmful for environment and health.
• the chemical recycling of POMs has not been the subject of extensive studies and few approaches focused on the transformation of POMs have been implemented.
• the present invention stems from the unexpected discovery by the inventor that polyacetal obtained from waste plastics can be used in the synthesis of polyoxymethylenedialkylethers, releasing little formaldehyde.
• the present invention therefore relates to a process for recycling polyacetal having from 8 to 100,000 carbon atoms to obtain a polyoxymethylenedialkylether product of formula R- (OCH2) n-OR ', in which R e ⁇ R' independently represent a methyl group or an ethyl group in an integer greater than or equal to 1, the process comprising a step of reacting an acid catalyst with a mixture comprising a polyacetal having from 8 to 100,000 carbon atoms, a reactive polyoxymethylenedialkylether of formula R- (OCH2) k-OR 'in which R e ⁇ R' is ⁇ as defined above e ⁇ k is ⁇ an integer greater than or equal to 1, e ⁇ optionally a solvent.
• the present invention also relates to the use of a reactive polyoxymethylenedialkylether of formula R- (OCH2) k-OR 'for the recycling of polyacetal having from 8 to 100,000 carbon atoms to obtain a polyoxymethylenedialkylether product of formula R- ( OCH2) n-OR '.
• the present invention also relates to the use of a polyoxymethylenedialkylether product obtained by the recycling process according to the invention for the synthesis of (meth) acrylic acid or ester, of (meth) acrolein or of neopentylglycol.
• the present invention also relates to a process for the synthesis of acid or ester (meth) acrylic or (meth) acrolein or neopentylglycol comprising a reaction step of a polyoxymethylenedialkylether product obtained by the recycling process according to invention.
• the process according to the invention is a process for recycling polyacetal.
• polyacetal is meant a homopolymer or copolymer based on formaldehyde.
• Polyacetal can be a mixture of homopolymers and / or copolymers based on formaldehyde.
• homopolymer means a formaldehyde polymer also called polyoxymethylene (POM) or polyformaldehyde.
• a homopolymer is usually in the form of a mixture of homopolymers of different chain lengths.
• copolymer means a polymer of formaldehyde e ⁇ of one or more monomers other than formaldehyde.
• a copolymer is generally in the form of a mixture of copolymers of different chain lengths.
• the polyacetal is a mixture of homopolymer and copolymer.
• the copolymer homopolymer mixture comprises less than 20%, preferably less than 15%, less than 10%, less than 9%, less than 8%, less than 7% or less than 6%, more preferably less than 5%, less than 4%, less than 3%, less than 2% or less than 1%, by weight of the copolymer based on the weight of the homopolymer blend of the copolymer.
• the polyacetal is a homopolymer.
• the polyacetal can have a number of carbon atoms ranging from 8 to 100,000, 8 to 50,000, 8 to 10,000 or 8 to 100.
• the polyacetal can have a number of carbon atoms. ranging from 100 to 100,000, 500 to 100,000, 1,000 to 100,000, 1,000 to 50,000, 3,000 to 50,000, or 3,000 to 10,000.
• the polyacetal can be obtained from waste of different materials, we speak of post-production or post-industrial polyacetal or post-consumer polyacetal.
• polyacetal may come from waste from the automotive, aeronautics, telecommunications, sports, leisure, electronics, electromechanics, etc. industries.
• the polyacetal can further comprise additives such as glass fibers, carbon fibers, carbon nanotubes, carbon black, pigments, etc.
• the polyacetal can also be contaminated with other polymers or contaminants, but in this case the waste to be recycled is chosen such that these other polymers / contaminants are inert in the recycling process, i.e. they do not dissolve and / or react during the reaction.
• the polyacetal is ground so as to obtain pieces of polyacetal of 0.05 to 2 cm.
• the pieces of polyacetal obtained after grinding do not exceed 1.5 cm, 1 cm, 0.8 cm, 0.5 cm, 0.3 cm, 0.2 cm, 0.1 cm or 0.05 cm.
• the pieces of ground polyacetal are dried using any method well known to those skilled in the art in order to remove traces of residual water.
• the pieces of polyacetal can be dried under vacuum or under a flow of nitrogen at a temperature preferably ranging from 20 ° C to 100 ° C, more preferably from 60 ° C to 100 ° C, for a period of time. preferably from 2 to 30 hours, more preferably from 5 to 60 hours.
• the polyacetal can be dried under a microwave flow, for a period of less than 30 minutes, preferably less than 10 minutes.
• Polvoxymethylenedialkylether Product [0026] The process according to the invention makes it possible to obtain a polyoxymethylenedialkylether produced from polyacetal, polyoxymethylenedialkylether reactive e ⁇ of an acid catalyst.
• the polyoxymethylenedialkylether produced may in particular include polyoxymethylenedialkylether resulting from the depolymerization of the polyacetal and optionally of the reactive polyoxymethylenedialkylether.
• the polyoxymethylenedialkylether produced corresponds to the formula R- (OCH2) n-OR ’, in which R e ⁇ R’ independently represent a methyl group or an ethyl group e ⁇ n is an integer greater than or equal to 1.
• the polyoxymethylenedialkylether product can be recovered at the end of the process according to the invention, in particular by a separation step, for example a distillation step.
• the recovery step isolates the polyoxymethylenedialkylether produced from the remaining reaction mixture.
• the recovery step is detailed below.
• the polyoxymethylenedialkylether produced may be a POMX n having a specific n value or a mixture of POMXn having different n values.
• the polyoxymethylenedialkylether produced is a mixture of POMXn.
• the polyoxymethylenedialkylether produced has a number n ranging from 1 to 100, preferably from 1 to 50, from 1 to 25 or from 1 to 15, more preferably from 1 to 10, even more preferably from 1 to 8.
• the polyoxymethylenedialkylether produced comprises less than 10% by weight of polyoxymethylenedialkylether having a number n greater than 8, more preferably less than 9%, less than 8%, less than 7%, less than 6%, less than 5%, less than 4%, less than 3%, less than 2%, by weight of polyoxymethylenedialkylether having a number n greater than 8 relative to the total weight of polyoxymethylenedialkylether produced.
• the polyoxymethylenedialkylether product can include methylal and / or ethylal at least in part from the reactive polyoxymethylenedialkylether introduced at the start of the process with the polyacetal.
• Methylal and / or ethylal can advantageously be separated from the rest of the polyoxymethylenedialkylether produced by an evaporation step, for example by distillation, and possibly be recycled at the start of the process as reactive polyoxymethylenedialkylether by a recycling step.
• the evaporation and recycling stages are described below.
• the polyoxymethylenedialkylether product is a mixture
• the polyoxymethylenedialkylether product is selected from the group consisting of CH3- (OCH2) -OCH3, CH3- (OCH2) 2-OCH3,
• the composition of POMM2-8 is ⁇ the next one : [Table 1]
• a preferred composition of a POMM2-8 compound is the following:
• the composition of POMM 2 -4 esf the following:
• the composition of POMM 3 -4 is the following one:
• the composition of POMM 3 -5 is the following one:
• the reactive polyoxymethylenedialkylether is contacted with the polyacetal and an acid catalyst to obtain the polyoxymethylenedialkylether product.
• the reactive polyoxymethylenedialkylether according to the invention corresponds to the formula R- (OCH2) k-OR 'in which R e ⁇ R' independently represent a methyl group or an ethyl group e ⁇ k es ⁇ an integer greater than or equal to 1.
• k is an integer ranging from 1 to 100, preferably from 1 to 50, from 1 to 25 or from 1 to 15, more preferably from 1 to 10, even more preferably from 1 to 8.
• the reactive polyoxymethylenedialkylether can be a POMXk with a specific k value or a mixture of POMXk with different k values.
• the reactive polyoxymethylenedialkylether comprises methylal and / or ethylal.
• the reactive polyoxymethylenedialkyl ether comprises non-recycled methylal and / or ethylal (also called fresh methylal and / or ethylal).
• a non-recycled compound or a fresh compound is a compound which does not come from a recycling step of the process.
• Fresh methylal and / or G ethylal can in particular be used to initiate the process according to the invention.
• the reactive polyoxymethylenedialkylether may contain methylal and / or recycled ethylal.
• a recycled compound is a compound which comes from a recycling step of the process.
• the reactive polyoxymethylenedialkylether comprises methylal and / or recycled ethylal as well as fresh methylal and / or ethylal.
• the reactive polyoxymethylenedialkylether can include one or more POMXk having a number k greater than or equal to 2.
• the reactive polyoxymethylenedialkylether can include compounds chosen from among POMM 2 , POMM3, POMM 4 , POMMs, POMM 6 , POMMz, POMMs, POMM of top row, POME 2 , POME3, POME 4 , POMEs, POME 6 , POMEz, POMEs, POMEs of higher rank and their mixtures. These compounds can be fresh or recycled.
• the reactive polyoxymethylenedialkylether comprises methylal and / or ethylal as well as one or more POMXk having a k greater than or equal to 2.
• the reactive polyoxymethylenedialkylether comprises only fresh methylal and / or ethylal.
• the reactive polyoxymethylenedialkyl ether comprises fresh methylal and / or ethylal as well as recycled methylal and / or ethylal.
• the reactive polyoxymethylenedialkylether comprises methylal and / or fresh ethylal, optionally methylal and / or recycled ethylal, e ⁇ in addition a mixture of POMXk having a number k greater than or equal to 2 fresh or recycled.
• the ratio of the mass of the reactive polyoxymethylenedialkylether to the mass of the polyacetal is at least 2: 1, preferably at least 2.5: 1, at least 3: 1, d at least 5: 1, at least 6: 1, at least 7: 1, at least 8: 1, or at least 9: 1.
• the reactive polyoxymethylenedialkylether comprises less than 5%, preferably less than 4%, less than 3%, less than 2% or less than 1%, by weight of POMXk having a k greater than 8 by weight total of POMXk having a k greater than or equal to 2.
• the method according to the invention comprises a reaction step between an acid catalyst e ⁇ a mixture comprising a polyacetal as defined above, a reactive polyoxymethylenedialkyl ether as defined above e ⁇ optionally a solvent.
• a liquid mixture means a mixture capable of flowing under its own weight at room temperature (20 ° C.).
• the reaction mixture can be a dispersion, i.e. a system containing solid pieces. of polyacetal dispersed in a liquid phase. This is because the polyacefal is generally in solid form and can be at least partly dissolved by the reactive polyoxymethylenedialkyl ether and optionally a solvent.
• the solvent advantageously makes it possible to facilitate the dissolution of the polyacetal. When only methylal and / or ethylal is used as the reactive polyoxymethylenedialkylether, the presence of solvent is not necessary.
• the solvent is chosen so as to have a boiling point higher than the boiling point of the polyoxymethylenedialkylether product that is to be obtained.
• the solvent has a boiling point greater than the boiling point. boiling of the product polyoxymethylenedialkylether having the highest n-value desired to be recovered.
• the other high boiling point POMs can then be recycled with the solvent at the start of the process by a recycling step.
• the solvent has a boiling point greater than 120 ° C under partial vacuum (i.e. about 10 mmHg), or a boiling point greater than 250 ° C corrected for atmospheric pressure. .
• the solvent can in particular be chosen from sulfolane, methylsulfolane, ethylsulfolane, diethylsulfolane, propylsulfolane, dipropylsulfolane, butylsulfolane, dibutylsulfolane, pentylsulfolane, dipentylsulfolane, hexylsulfolane, octylsulfolane, hexylsulfolane DMSO and their mixtures.
• the solvent is sulfolane.
• sulfolane has a boiling point of 285 ° C
• methylsulfolane has a boiling point of 278 ° C
• DMSO has a boiling point of 189 ° C, in standard conditions of temperature and pressure (25 ° C and atmospheric pressure).
• the solvent is added in an amount ranging from 20% to 80%, more preferably from 30% to 70%, even more preferably from 40% to 60% by mass of solvent relative to the total mass of the solvent. mixed.
• the amount of solvent in the mixture is about 50% by mass relative to the total mass of the solvent + reactive polyoxymethylenedialkyl ether mixture.
• the mixture is dissolved at a temperature below 120 ° C, preferably from 20 ° C to 120 ° C, more preferably from 40 ° C to 110 ° C, preferably at a pressure ranging from atmospheric pressure at 10 Bars.
• the acid catalyst can be a homogeneous or a heterogeneous catalyst.
• the catalyst is a heterogeneous catalyst.
• the use of a heterogeneous catalyst advantageously makes it possible to facilitate its removal by filtration at the end of the reaction step.
• a catalyst suitable for the process according to the invention it is possible to cite acidic resins, for example resins of the Amberlys ⁇ R e ⁇ Lewa ⁇ i ⁇ R type , Lewis acids.
• an acidic resin is a cation exchange macroporous polymeric resin (for example a styrene-divinylbenzene copolymer) capable of supplying H + ions.
• the catalyst is selected from the group consisting of acidic resins; organic or mineral acids such as trifluoromethanesulfonic acid, perchloric acid, methanesulfonic acid, paratoluenesulfonic acid, and sulfuric acid; Lewis acids such as BF3, AsFs; mixed acid oxides, such as WO3 / T1O2, phosphate alumina, tungsten alumina and zeolites; e ⁇ their mixtures.
• organic or mineral acids such as trifluoromethanesulfonic acid, perchloric acid, methanesulfonic acid, paratoluenesulfonic acid, and sulfuric acid
• Lewis acids such as BF3, AsFs
• mixed acid oxides such as WO3 / T1O2
• phosphate alumina, tungsten alumina and zeolites e ⁇ their mixtures.
• the polyacetal is initially at least partially dissolved with the reactive polyoxymethylenedialkyl ether and optionally a solvent and then the mixture is placed in the presence of the acid catalyst.
• the polyacetal is first placed in the presence of the acid catalyst e ⁇ of a solvent, then the reactive polyoxymethylenedialkyl ether is added.
• the latter is present in an amount ranging from 0.01 to 10 mol per kg of polyacetal, preferably from 0.02 to 5, more preferably of 0.05 to 2 moles per kg of polyacetal.
• the reaction carried out in the presence of the acid catalyst is carried out at a temperature below 120 ° C, preferably from 20 ° C to less than 120 ° C, more preferably from 40 ° C to 115 ° C. or from 60 to 110 ° C e ⁇ even more preferably from 80 ° C to 110 ° C, at a pressure ranging from 1 to 10 Bars e ⁇ preferably from 5 to 10 Bars to prevent the mixture from boiling .
• the reaction can be carried out in batch mode or in continuous mode.
• the catalyst is preferably stirred with the mixture, but it can also be put in a wire basket, itself put in rotation in the reactor.
• the catalyst is preferably placed in a fixed or fluidized bed.
• the mixture containing the polyacefal, the reactive polyoxymefhylenedialkylefher and optionally the solvent passes through the catalyst bed from top to bottom or from bottom to top.
• the liquid passes through the catalyst bed from bottom to top, and the catalyst grains retain mobility in the catalyst bed without being entrained.
• the method according to the invention can include a filtration step.
• a step of filtering the mixture is carried out before the step of reaction with the acid catalyst in order to retain any contaminants, namely the additives present in the polyacefal and / or the pieces of undissolved polyacefal, mineral fillers such as glass or carbon fibers, other undissolved polymers.
• a filtration step is carried out prior to the formation of the mixture comprising the polyaceafal with at least one reactive polyoxymethylenedialkyl ether e ⁇ optionally a solvent.
• the polyacefal is at least partially dissolved in a suitable solvent and a filtration step is carried out in order to remove any contaminants, namely the additives present in the polyacefal, and / or the pieces of non-polyacefal. dissolved, mineral fillers such as glass or carbon fibers, other undissolved polymers.
• a suitable solvent it is possible to cite the solvents defined above.
• a filtration step is performed after bringing the mixture into contact with a catalyst and optionally neutralizing the latter, in order to remove the solid particles, in particular any contaminants, to namely the additives present in the polyacefal, and / or the pieces of undissolved polyacefal, mineral fillers such as glass or carbon fibers, other undissolved polymers and / or particles of acidic or anionic resins.
• the process according to the invention can include a step of separating the catalyst.
• the optional catalyst separation step is carried out after the reaction step.
• the optional catalyst separation step can be carried out by filtration or centrifugation when the acid catalyst is dispersed in the reaction medium. Alternatively, if the acid catalyst is contained in a mesh basket, it is sufficient to remove the mesh basket from the reactor.
• the process according to the invention can include a neutralization step.
• the optional neutralization step is performed after the reaction step.
• the optional neutralization step can be carried out with a base so as to remove traces of residual acid.
• a base Any basis well known to those skilled in the art to do this can be used.
• this an aqueous solution of soda, a mefhanolic solution of soda, sodium or potassium mefhylafe, a solution of soda in methylal, anhydrous soda, potash, lime, an ammonia solution, friefhylamine, diisopropylefhylamine, melamine, or an anionic resin such as Ambersep 900 OH resin.
• the base is anhydrous.
• the process according to the invention can include an evaporation step.
• the light compounds are festively removed from the evaporator unit.
• the evaporation step can be carried out with an evaporation unit chosen from a rotary evaporator ef / or a distillation column. Evaporation can be carried out in one step or in several successive steps.
• the evaporation step is preferably a step of distillation at atmospheric pressure or under reduced pressure at a lower temperature, for example at a temperature below 120 ° C, preferably below 110 ° C at atmospheric pressure, or under reduced pressure, for example ranging from 0.4 to 0.6 a ⁇ m. All or part of the light compounds removed during the evaporation step can be reintroduced into the reaction step in the form of a reactive polyoxymethylenedialkylether.
• the method according to the invention may include a step of recovering the polyoxymefhylenedialkylefher product.
• the recovery step can ⁇ make it possible to separate the polyoxymethylenedialkylether produces heavy compounds.
• the heavy compounds can be POMX n with n greater than the maximum value of n of the polyoxymethylenedialkylether produced, in particular greater than 4, greater than 5, greater than 6, greater than 7, greater than 8 or greater than 10.
• the step of recovery can in particular be carried out by distillation.
• the heavy compounds remain at the bottom of the distillation and the desired product polyoxymethylenedialkylether is collected at the top of the distillation.
• the distillation is preferably carried out under partial vacuum.
• the heating temperature is advantageously kept below 120 ° C. In fact, heating above 120 ° C could degrade the polyoxymethylenedialkylether produced.
• the vacuum level and the heating temperature are adjusted to distill the target chain length POMXn.
• the distillation can be carried out under partial vacuum, at a pressure preferably ranging from 5 mBars to 60 mBars. Those skilled in the art can easily select the temperature-pressure pair which corresponds to the polyoxymethylenedialkylether product which he wishes to obtain. All or part of the heavy compounds removed during the distillation step can be reintroduced into the reaction step in reactive polyoxymethylenedialkyl ether.
• the process according to the invention can include a recycling step.
• the recycling step can in particular make it possible to reintroduce into the reaction step part of the compounds of formula R-fOChhjn-OR ’with n greater than or equal to 1 contained in the reaction mixture. These compounds can be used as reactive polyoxymethylenedialkylether.
• the recycling stage makes it possible to reintroduce all or part of the light compounds eliminated in the evaporation stage and / or all or part of the heavy compounds eliminated in the recovery stage in the reaction stage in tan ⁇ than reactive polyoxymethylenedialkylether.
• the methylal (POMMi) and / or ethylal (POMEi) recovered during the evaporation step is reintroduced into the reaction step as a reactive polyoxymethylenedialkyl ether.
• the desired product polyoxymethylenedialkylether all or part of the heavy compounds, preferably POMXn having an n number of less than 8, can also be reintroduced into the reaction step as reactive polyoxymethylenedialkylether.
• the polyoxymethylenedialkylether product obtained with the recycling process according to the invention can be used as raw material for the synthesis of other organic compounds, in particular the (meth) acrylic acid or ester, (meth) acrolein or neopentylglycol.
• the method according to the invention can comprise a step of synthesis of acid or of (meth) acrylic ester or of (meth) acrolein or of neopentyl glycol from the polyoxymethylenedialkyl ether produced.
• the synthesis of acid or ester (meth) acrylic or (meth) acrolein or neopentylglycol can be carried out under the conditions described below.
• the polyoxymethylenedialkylether product obtained by the polyacetal recycling process according to the invention can be used as a substitute or additive for diesel fuel, as a methanol substitute in fuel cells as well as for the preservation of the human or animal body and / or the embalming of dead bodies.
• polyoxymethylenedialkylether product obtained by the polyacetal recycling process according to the invention in particular POMM2-8, POME2-8 OR POMM / E2-8 optionally mixed with methylal and / or ethylal , can be used as reagents or synthesis intermediates, in particular for the synthesis of acid or ester (mefh) acrylic or of (mefh) acrolein or neopentylglycol.
• the synthesis of acid or ester (mefh) acrylic or (mefh) acrolein is preferably carried out by an aldol condensation reaction.
• the synthesis of (meth) acrylic acid or ester or of (meth) acrolein is carried out by reacting a polyoxymethylenedialkylether product obtained by the polyacetal recycling process according to the invention with a carboxylic acid or a suitable ester or a saturated aldehyde in the presence of a catalyst.
• the polyoxymethylenedialkylether produced makes it possible to avoid the use of free formaldehyde which simplifies the separation of acid or ester (mefh) acrylic or (mefh) acrolein produced.
• carboxylic acids and esters which can be used for the synthesis of acid or of (meth) acrylic ester or of (meth) acrolein are well known to those skilled in the art.
• carboxylic acid it is possible to cite propionic acid and acetic acid.
• ester it is possible to cite esters of propanoic acid, such as methyl propionate, ethyl propionate, propyl propionate and butyl propionate or methyl acetate.
• aldehyde it is possible to cite acetaldehyde and propana idehyde.
• the catalyst used for the synthesis of acid or of (meth) acrylic ester or of (meth) acrolein can be chosen from any acid or basic catalyst well known to those skilled in the art for this type of product. reaction.
• a suitable catalyst it is possible to cite catalysts based on phosphates and / or silicates of magnesium, calcium, aluminum, zirconium, thorium, strontium hydroxyapatite, sodium hydroxyapatite. barium, a silica doped with an alkali or a lino-earth alkali and / or zirconium, calcium hydroxyapatite and their mixture.
• an alcohol in the process of synthesizing (meth) acrylic acid or ester or (meth) acrolein.
• This alcohol can serve as a solvent for the reaction. Any alcohol well known to those skilled in the art for this type of synthesis can be used.
• a suitable alcohol it is possible to cite methanol, ethanol, propanol, isopropanol, isobutanol, t-butyl alcohol, phenol, n-butanol and alcohol ch loroca pryliq ue.
• neopentylglycol is preferably carried out by an aldol condensation reaction.
• the synthesis of neopentylglycol is carried out by reacting a polyoxymethylenedialkylether product obtained by the polyacetal recycling process according to the invention with isobutyraldehyde.
• neopentylglycol is catalyzed by a tertiary alkylamine compound. It is also possible to add an alcohol in the neopentylglycol synthesis process. This alcohol can serve as a solvent for the reaction. Any alcohol well known to those skilled in the art for this type of synthesis can be used. As an example of a suitable alcohol, it is possible to cite methanol.
• the pressure in the autoclave gradually increases, then stabilizes at less than 6 Bars with temperature.
• the dissolved mixture is sent to the reactor, passing through a filter which retains any contaminants ef / or undissolved polymer.
• a bed of Amberlysf® 15Dry acid resin (Dupont) was placed above a grid.
• the Amberlysf® 15Dry resin (1325 kg) was washed beforehand with methanol, then dimethoxymethane, in order to remove the traces of residual water.
• the previously dissolved mixture is sent to the reactor in an ascending flow. It is dispersed through the catalyst bed by the lower distribution plate.
• the acidic resin beads are free to move when the reactor is operated in upflow, however the linear velocity of the liquid is not sufficient to entrain catalyst particles.
• the residence time of the liquid mixture in the reactor namely the ratio of the volume of resin (catalytic resin bed) to the flow rate of polyacetal solution in the POMMi, is 1 hour.
• the temperature of the solution which feeds the reactor is maintained below 120 ° C and in particular at 115 ° C.
• the reactor operates under a pressure of 10 bars to prevent boiling of the reaction solution.
• the mixture resulting from the reaction is then directed to a distillation column. The pressure is brought back to atmospheric pressure, and the temperature has dropped to 25 ° C.
• a concentrated sodium hydroxide solution is added to neutralize the traces of acidic resin which have been entrained with the reaction mixture. Then the mixture is taken to the distillation stage.
• the temperature at the top of the column is 42 ° C, and 80 ° C at the bottom of the column.
• the dimethoxymethane is obtained, condensed, and is returned to the dissolution autoclave (475 kg) for the following operation.
• the mixture of POMM2-8 + is obtained.
• a mixture which contains 331 kg of POMM2, 212 kg of POMM3, 130 kg of POMM4, 76 kg of POMMs, 44 kg of POM / VW, 25 kg of POMMz, 14 kg of POMMs and 16 kg of POMMs of higher ranks is obtained , determined by chromatographic analysis.
• the autoclave is then closed and heated to 110 ° C.
• the pressure in the autoclave gradually increases, then stabilizes with temperature.
• the dissolved mixture is sent to the reactor, passing through a filter which retains any contaminants and / or undissolved polymer.
• the residence time of the liquid mixture in the reactor namely the ratio of the volume of resin (catalytic resin bed) to the flow rate of polyacetal solution in the POMMi, is 1 hour.
• the temperature of the solution which feeds the reactor is kept below 120 ° C, in particular 110 ° C.
• the reactor operates under a pressure of 10 bars to prevent the reaction solution from boiling.
• the mixture resulting from the reaction is then directed to a distillation column.
• the pressure is reduced to atmospheric pressure.
• Friefhylamine is injected into the solution in order to neutralize the acidity associated with the presence of fine particles of catalyst (Amberlys ⁇ ® resin) which are carried out of the reactor.
• the column feast temperature is 106 ° C. and 120 ° C. at the bottom of the column.
• a mixture of dimefoxymefhane, POMMi, and POMM2 is obtained, condensed, and is returned to the dissolving autoclave (1799 kg of light mixture of POMMi (1060 kg) and POMM2 (739 kg) .
• the mixture of POMM 3+ is obtained.
• the bottom of the column is then sent to another distillation column operated under partial vacuum (60 mbar).
• the mixture of POMM 3 and POMM4 is distilled and condensed; 763 kg of a mixture of POMM 3 (474 kg) and POMM4 (289 kg) are then obtained.
• the mixture of higher POMMs is recovered. 171 kg of POMMs, 98 kg of POM / VW, 56 kg of POMMz, 31 kg of POMMs, and 37 kg of POMMs from higher ranks are obtained which are sent back to the dissolution autoclave.
• the column feast temperature is 105 ° C, e ⁇ 120 ° C at the bottom of the column.
• the mixture of POMMi e ⁇ of POMM2 is obtained, condensed, e ⁇ is ⁇ returned to the dissolution autoclave (POMMi (829 kg) e ⁇ POMM2 (578 kg)).
• the mixture of POMM 3+ is obtained.
• the bottom of the column is then sent to another distillation column operated under partial vacuum (10 mBars), e ⁇ at a temperature of 120 ° C. at the bottom.
• the mixture of POMM 3 , POM / VUe ⁇ POMM5 is ⁇ distilled and condensed (371 kg of POMM3, 226 kg of POMM4 and ⁇ 134 kg of POMMs). At the bottom of the column, the mixture of the upper POMMs is recovered. 77 kg of POM / VW, 44 kg of POMMz, 24 kg of POMMs, e ⁇ 29 kg of POMMs from higher ranks are ⁇ obtained and sent back to the dissolution autoclave.
• the autoclave is then closed and heated to 80 ° C.
• the pressure in the autoclave gradually increases, then stabilizes with temperature.
• the dissolved mixture is sent to the reactor, passing over a filter which retains any contaminants and / or undissolved polymer.
• the previously dissolved mixture is sent to the reactor in an upward flow, that is to say through the bottom of the reactor. It is dispersed through the catalyst bed by the lower distribution plate.
• the acidic resin beads are free to move when the reactor is operated in upflow, however the linear velocity of the liquid is not sufficient to entrain catalyst particles.
• the residence time of the liquid mixture in the reactor namely the ratio of the volume of resin (catalytic resin bed) to the flow rate of polyacefal solution in POMMi and the solvent is 0.5 hours.
• the temperature of the solution which feeds the reactor is kept below 120 ° C, and specifically at 80 ° C.
• the reactor operates under a pressure of 5 bar to prevent the reaction mixture from boiling.
• the temperature at the column festival is 45 ° C, and 80 ° C at the bottom of the column.
• the dimethoxymethane is obtained, condensed (380 kg), and is returned to the dissolving autoclave.
• the mixture of POMM2 + and sulfolane is obtained.
• the bottom of the column is then sent to another distillation column operated under partial vacuum (50 mBars).
• the mixture of POMM2, POMM3 and POMM4 is distilled and condensed (177 kg of POMM2, 76 kg of POMM3 and 31 kg of POMM4).
• the mixture of the upper POMMs is recovered. 12 kg of POMMs, 5 kg of POM / VW, 2 kg of POMM7, 1 kg of POMMs, and 582 kg of sulfolane are obtained and returned to the dissolution autoclave.
• Example 5 Production of POMM3-4 [01 19] 100 kg of post-industrial homopolymer polyacetal, previously ground to have pieces not exceeding 0.1 cm, and dried under vacuum at 80 ° C for 8 hours, are added in 1 1 1 kg of fresh dimethoxymethane, at room temperature in an autoclave.
• the autoclave is then closed and heated to 100 ° C.
• the pressure in the autoclave gradually increases, then stabilizes with temperature.
• the dissolved mixture is sent to the reactor, passing through a filter which retains any contaminants and / or undissolved polymer.
• a bed of Amberlys ⁇ ® 15Dry acidic resin was placed over a grid.
• Amberlys ⁇ ® 15Dry resin was washed beforehand with methanol, then dimethoxymethane, in order to remove traces of residual water.
• the previously dissolved mixture is sent to the reactor in an upward flow, that is to say through the bottom of the reactor. It is dispersed through the catalyst bed by the lower distribution plate.
• the acidic resin beads are free to move when the reactor is operated in upflow, however the linear velocity of the liquid is not sufficient to entrain catalyst particles.
• the residence time of the liquid mixture in the reactor namely the ratio of the volume of resin (catalytic resin bed) to the flow rate of polyacetal solution in DMM and the solvent is 0.5 hour.
• the temperature of the solution which feeds the reactor is kept below 120 ° C, specifically here 105 ° C.
• the reactor operates under a pressure of 10 bars.
• the mixture resulting from the reaction is then directed to a distillation column. The pressure is reduced to atmospheric pressure.
• the temperature at the top of the column is 105 ° C., e ⁇ 120 ° C. at the bottom of the column.
• the mixture of dimethoxymethane (POMMi) e ⁇ the POMM2 is obtained, condensed (POMMi (493 kg) e ⁇ POMM2 (275 kg)), e ⁇ is ⁇ returned to the dissolution autoclave.
• the mixture of POMM3 + ef of sulfolane is obtained.
• the bottom of the column is then sent to another distillation column operated under partial vacuum (40 mBars).
• the mixture of POMM3 and ⁇ POMM4 is ⁇ distilled and condensed; 141 kg of POMM3 e ⁇ 69 kg of POMM4 mixed. At the bottom of the column, the mixture of the upper POMMs is recovered. 61 kg of a mixture of POMM 5+ containing 33 kg of POMMs, 15 kg of POM / VW, 7 kg of POMM7, 3 kg of POMMs, e ⁇ 3 kg of POMMs of higher ranks e ⁇ of 750 kg of sulfolane its ⁇ obtained and ⁇ returned to the dissolving autoclave.
• the aufoclave is then closed and heated to 110 ° C.
• the pressure in the autoclave gradually increases, then stabilizes with temperature.
• the dissolved mixture is sent to the reactor, passing through a filter which retains any contaminants ef / or undissolved polymer.
• the column feast temperature is 106 ° C, e ⁇ 120 ° C at the bottom of the column.
• 427 g of POMMi light mixture (261 g) and POMM2 (166 g) are ⁇ condensed and returned to the dissolution autoclave for a subsequent operation.
• the mixture of POMM3 + is obtained.
• the bottom of the column is then sent to another distillation column operated under partial vacuum (under 8 mbar).
• the mixture of POMM3, POMM4 and ⁇ POMMs is distilled with a false reflux strength and condensed; a mixture of 97 g of POMM3, 54 g of POMM4 e ⁇ 29 g of POMMsesf recovered.
• the residence time of the liquid mixture in the reactor namely the ratio of the volume of resin (catalytic resin bed) to the flow rate of polyacetal solution in the mixture of reactive POMMs, is 1 hour.
• the temperature of the solution which feeds the reactor is kept below 120 ° C e ⁇ in particular at 100 ° C.
• the reactor operates under a pressure of 8 bars to prevent any boiling of the reaction solution.
• the mixture resulting from the reaction is then directed to a distillation column.
• the pressure is reduced to atmospheric pressure, e ⁇ the temperature es ⁇ dropped back to 25 ° C.
• a concentrated soda solution is added to neutralize any traces of acidic resin which have been carried over with the reaction mixture. Then the mixture is taken to the distillation stage.
• the temperature at the top of the column is 42 ° C, e ⁇ 80 ° C at the column bottom, then the pressure is gradually reduced to continue the distillation.
• the dimethoxymethane e ⁇ a part of POMM2 is obtained, condensed, e ⁇ is ⁇ returned to the dissolution autoclave (832 kg of POMMi e ⁇ 101 kg of POMM2) for the next operation.
• the mixture of POMM2-8 + is obtained.
• a mixture that contains 179 kg of POMM2, 120 kg of POMM3, 49 kg of POMM4, 19 kg of POMMs, 7 kg of POM / VW, 3 kg of POMMz, 1 kg of POMMs and less than 1 kg of row POMMs superiors are obtained.
• the mass composition is therefore 47% by weight of POMM2, 32% by weight of POMM3, 13% by weight of POMM4, 5% by weight of POMMs, 2% by weight of ROMM ⁇ , 1% by weight of POMMz, 0.3% by weight of POMMs e ⁇ less than 1% by weight of POMMs of higher ranks.

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• 2020
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