Classifications

• • 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
  • C08J11/24—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 containing hydroxyl groups
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
  • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
  • B01J23/74—Iron group metals
  • B01J23/745—Iron
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
  • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
  • B01J23/74—Iron group metals
  • B01J23/755—Nickel
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J35/00—Catalysts, in general, characterised by their form or physical properties
  • B01J35/60—Catalysts, in general, characterised by their form or physical properties characterised by their surface properties or porosity
  • B01J35/61—Surface area
  • B01J35/612—Surface area less than 10 m2/g
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
  • B01J37/08—Heat treatment
  • B01J37/082—Decomposition and pyrolysis
  • B01J37/086—Decomposition of an organometallic compound, a metal complex or a metal salt of a carboxylic acid
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C67/00—Preparation of carboxylic acid esters
  • C07C67/48—Separation; Purification; Stabilisation; Use of additives
  • C07C67/60—Separation; Purification; Stabilisation; Use of additives by treatment giving rise to chemical modification
• • 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
  • C08J11/16—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 inorganic material
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2235/00—Indexing scheme associated with group B01J35/00, related to the analysis techniques used to determine the catalysts form or properties
• • 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
  • C08J2367/00—Characterised by the use of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Derivatives of such polymers
  • C08J2367/02—Polyesters derived from dicarboxylic acids and dihydroxy compounds

Definitions

• the invention relates to a method of catalysed depolymerisation of condensation polymers.
• the invention further relates to a catalyst composition for use in depolymerisation of condensation polymers.
• Condensation polymers such as polyesters and polyamides are produced in large quantities and used for a variety of applications, including textile materials, packaging of food and liquid cleaning compositions and industrial applications.
• polyesters include polylactic acid and polyethylene terephthate (PET) and polyamides such as a variety of types of nylon, for instance nylon-6, nylon-6,6, nylon-4,6 and so on.
• PET polyethylene terephthate
• polyamides such as a variety of types of nylon, for instance nylon-6, nylon-6,6, nylon-4,6 and so on.
• condensation polymers end up as waste, which needs to be processed.
• condensation polymers are often combusted in incineration plants.
• PET used for textile and/or for packages such as bottles.
• nanoparticles as a depolymerisation catalyst.
• Such nanoparticles have a small diameter and therewith a high surface area, for instance of lOmVg or more. This high surface area allows for significant adsorption of the condensation polymer, which is believed to result is quick depolymerisation and therewith an economically feasible process.
• a catalyst that comprises both a nanoparticle and a functional group known per se as magnetic fluid.
• the latter is more particularly a positively charged organic aromatic compound.
• the aromatic compound suitably is a nitrogen-containing heterocyclic moiety. This may be grafted onto the nanoparticle via a bridging moiety, for instance based on an organosilicon compound.
• Such a catalyst is for instance disclosed in WO2016/105198 Al .
• the invention relates to a catalyst composition
• a catalyst composition comprising particles of a transition metal in an alcoholic carrier liquid, which is at least substantially water-free.
• the invention relates to a method of catalytic depolymerisation of a condensation polymer into monomers and/or oligomers, which method comprises the steps of: (1) providing the condensation polymer in a solid form and further providing particles of transition metal; (2) mixing the condensation polymer with the transition metal particles in alcohol to obtain a reaction mixture; (3) processing the reaction mixture at elevated temperature, at which the condensation polymer is dispersed and optionally dissolved into the alcohol and decomposed into oligomer and/or monomer, wherein the transition metal particles act as a catalyst and wherein the alcohol is a reagent in the depolymerisation, and wherein the monomer and optionally oligomer dissolve in the alcohol to form an alcohol solution; (4) separating the alcohol solution from solids, including the transition metal particles, and (5) providing a catalyst composition comprising the transition metal particles for reuse as catalyst.
• the resulting metal ions for instance Fe and/or Fe + may be active in the catalysis.
• the surface layer of the transition metal particle contributes, for instance in that the alcoholic carrier liquid such as a glycol would be adsorbed and be activated, enabling complexation with the carbonyl-group of the condensation polymer.
• the dissolution rate is sufficiently low so that a transition metal particle may be reused as a catalyst a plurality of times.
• the catalyst can be reused at least five times, more preferably at least ten times, or even at least twenty times. How often a catalyst can be reused, will further depend on - among others - the concentration of catalyst, the initial size of the transition metal catalyst particle, the separation method, and the type of transition metal.
• the transition metal particles that are apparently able to be dissolved anyhow survive a single run, in which the temperature exceeds 150 °C and preferably is in the range of 180-220°C, further dependent on the used alcohol.
• the alcohol adsorbs on the surface of the particle and possibly by forming an alkoxide bond (TM-O-C, wherein TM refers to a transition metal). This adsorption may limit dissolution, and may at the same time resulting in activation towards the condensation polymer, and particularly any carbonyl group therein.
• Such a low loading of the catalyst is highly surprising and also beneficial, since a low catalyst loading results in a lower dissolution of catalyst into the alcohol and therewith less ions to be removed again, for instance by means of an absorption treatment, suitably with an active carbon col mn.
• the size range herein defines the diameter.
• the diameter is herein measured by means of electron microscopy.
• Particles in this size range are sufficiently big to be separated from the product solution by means of a conventional separation technology such as filtering or a centrifuge treatment. At the same time, they are sufficiently small to obtain a good distribution of the particles and to allow that the particle surface may get close to the solid polymer, resulting in highly effective catalysis.
• a preferred particle size is from l -10 m.
• the transition metal particles such as nickel particles and iron particles
• the transition metal particles have a low surface area and are substantially non-porous.
• the surface area is less than 3m ⁇ 7g, preferably at most lm 2 /g or even less than 0.6m 2 /g.
• the porosity is suitably less than 10 2 cm'/g or even less for instance at most 10° cm 3 /g.
• non-porous transition metal particles can be suitably prepared by thermal decomposition of carbonyl complexes such as iron pentacarbonyl and nickel tetracarbonyl.
• the inventors have understood that a non-porous particle tends to be more suitable than a porous particle, since its exposure to the alcohol is less, and therefore, the corrosion of the particle is less and the particle can be reused more often for catalysis.
• any oxidation at the surface results in a low quantity of metal-ions and therewith a low level of ions that are present in the product stream as a contaminant to be removed therefrom.
• the transition metal particle is an iron particle, and it is further provided with an iron oxide surface.
• the presence of an iron oxide surface may further enhance catalysis.
• the oxide surface may be formed by itself, in contact with air, in contact with water, or the oxide surface may be applied deliberately.
• the alcohol is preferably chosen from the group of aliphatic alcohols.
• an alcohol with a boiling point above 150°C which is further able to participate in the decomposition of the condensation polymer as a reagent.
• polyols are preferred. Suitable polyols are for instance glycerol, propylene glycol and ethylene glycol. A most preferred alcohol is ethylene glycol. This results in glycolysis of the condensation polymer, more particularly the ester. Due to the presence of two alcohol-groups per molecule, the monomer is provided with one free alcohol-group, and is therewith capable of reacting again with an acid to form an ester.
• the condensation polymer is generally chosen from the group of polyesters, polyamides, polyimides and polyurethanes.
• the polymer is at least one of a polyester, a polyether, such as poly-oxymethylene (POM), polyethylene glycol (PEG), polypropylene glycol (PPG), polytetramethyleneglycol (PTMG), polyethylene oxide (PEO), polypropylene oxide (PPO), polytetrahydrofuran (PTHF), and polytetramethyleneetherglycol (PTMEG).
• a polypeptide such as any type of nylon, including nylon-6 and nylon-6,6, a polyamine, a
• polycondensate preferably a polyester, such as poly carboxylic ester, wherein the poly carboxylic ester is preferably selected from polyethylene terephthalate (PET), polyethylene furanoate (PEF), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polyglycolic acid (PGA), polylactic acid (PLA), polycaprolactone (PCL), polyethylene adipate (PEA), polyhydroxyalkanoate (PHA), polyhydroxybutyrate (PHB), polyethylene naphthalate (PEN), Poly(3-hydroxybutyrate-co-3- hydroxyvalerate) (PHBV), and a polycondensate of 4-hydroxybenzoic acid and 6- hydroxynaphthalene-2-carboxylic acid (VECTRAN).
• PET polyethylene terephthalate
• PET polyethylene furanoate
• PBT polybutylene terephthalate
• PTT polytrimethylene terephthalate
• PGA polyg
• depolymerisation An example of such optional (pre-)processing is the subdivision of the articles into smaller parts, for instance parts with a typical size of 2 x 2 cm or less, and typically at least 0.2 x 0.2 cm.
• Another example of such preprocessing is any separation of polymers in the waste polymer product, such as a separation between nylon and PET.
• a preheating step in the alcohol is another example of such optional preprocessing.
• a preferred process for the depolymerisation of the condensation polymer, such as PET, is specified in the method of catalytic depolymerisation as specified hereinabove and including several steps.
• Such process involves after the provision of the catalyst, the condensation polymer and the alcohol the heating to elevated temperature, so as to achieve an acceptable reaction rate; the dispersing of the solid condensation polymer into the alcohol (said dispersing typically also comprising at least some depolymerisation), the decomposition of the condensation polymer into oligomers and monomers, and the separation of a solution with the dissolved monomers and any dissolved oligomers on the one hand and non-dissolved parts on the other hand.
• the non-dissolved parts typically comprise the transition metal particles, thus the catalyst.
• Further non-dissolved parts may include any pigment, dyes or other colorants and fillers present in the solid condensation polymer, any oligomer to the extent that is not fully dissolved, and any polymers of a different type that have not been depolymerised.
• the elevated temperature is for instance a temperature that is at most 20°C lower than the boiling point of the alcohol used.
• ethylene glycol is the preferred alcohol, and the elevated temperature is suitably in the range of 180-200°C.
• the dispersing of the solid condensation polymer and the decomposition of the condensation polymer into oligomers and monomers may occur simultaneously. It is believed that the present catalyst particularly accelerates the first step of dispersing, possibly combined with some depolymerisation. In view thereof, it is believed that the present catalyst composition is particularly suitable for the degradation of a semicrystafline polymer.
• centrifugation filtration or membrane filtration.
• use is made of centrifugation, which is an industrially viable technology.
• use is made of filtration, more preferably microfiltration, which is one form of membrane filtration, or alternatively by means of a conventional filter with pore size of 1 micron. These are cost effective separation techniques for micron-sized particles.
• the filtration step is carried out at temperatures above 80°C. This is deemed suitable to ensure an adequate processing and prevent viscous behaviour of the reaction mixture.
• a hydrophobic polymer membrane such as based on polypropylene (PP), polyethylene (PE) and/or polytetrafluoroethylene (PTFE).
• a membrane filter of a PTFE membrane is deemed suitable, as it may be operated at temperatures well above 80°C, for instance in the range of 120-180°C.
• the filter size can be chosen in the range of 0.1-4 microns, such as 0.5-1 micron, further dependent on the particle size of the resulting product.
• the process is configured so as to remove the transition metal particles from the reaction mixture prior to adding water. This is deemed preferable, so as to prevent oxidation of the transition metal particles by means of the water, which will increase the concentration of ions in the resulting product stream comprising monomers.
• the catalyst is for instance removed by means of filtration or membrane filtration.
• the particles may be nanoparticles or larger particles or aggregates of nanoparticles, such as described in the non-prepublished application NL2017033, which is herein included by reference.
• Said additive is understood to ensure that colour is included in a solid mixture of colorant, oligomer and/or any polymer, which solid mixture is formed, in one suitable embodiment, upon the addition of water.
• the additive described in said non-prepublished application is also known as a catalyst for depolymerisation.
• it when added as an additive for colour removal, it may be present in smaller quantities, for instance in amounts of less than 1 wt%, or preferably less than 0.5 wt%, or even less than 0.2wt%.
• the particles may have larger dimensions.
• said additive may be added at a later stage of the process, for instance after removal of the transition metal particles.
• the invention further relates to a catalyst composition.
• the transition metal particles are dispersed into a carrier liquid which composition is substantially free of water.
• the carrier liquid comprises at least one alcohol.
• the alcohol is suitable as a solvent and reagent during the depolymerisation of the condensation polymer.
• a very suitable example of an alcohol is a glycol, such as ethylene glycol.
• the content of transition metal particles in the catalyst composition is in the range of 5- 20wt%, such as 7-15 wt%.
• the catalyst composition further comprises further particles to which are grafted catalytic groups comprising a positively charged organic compound (or group).
• the charged organic compound is a heterocyclic and particularly heteroaromatic compound, such as a compound containing a pyridinium, an imidazolium, a piperidinium, a pyrrolidinium, a pyrazolium, a thiazolium, a quaternary ammonium or a quaternary phosphonium ion, wherein said ions are substituted with one or more alkyl-groups.
• One of said alkyl groups is provided with a linking group for adsorption and/or reaction to the surface of the particles.
• Suitable linking groups are carboxylic acid groups and silanol groups as typically derived from tetraethylene-orthosilicate (TEOS).
• TEOS tetraethylene-orthosilicate
• the positively charged organic compound contains an imidazolium-ion, for instance a dialkyl-imidazolium-ion, such as an alkyl-imidazolium- C 2 -C4-alkyl-trialkoxysilane, which will react with the particle surface as a silanol-group derived from one or more of said trialkoxy-groups.
• the particles may herein be the micron-sized transition metal particles, but is alternatively and preferably distinct particles.
• the size of the particles is for instance from 2 nm to 10 microns.
• use is made of particles in the range of 100 nm to 10 microns, more preferably from 200 nm to 5 microns or even from 400 nm to 2 microns.
• the size is herein defined as defined by electron microscopy. It refers to a size range such that at least 90vol% of the particles has a size within the said range, more preferably at least 95vol% or even at least 98vol% of the particles.
• the nature of the particles used herein may be variable, for instance an iron oxide or other oxide, more particularly a ferrite such as hematite, magnetite, maghemite.
• a ferrite such as hematite, magnetite, maghemite.
• One example hereof is known from WO2016/105198A1.
• particles with a larger particle size such as at least 100 nm are deemed preferred.
• the particles suitably have a surface area of at least 5 m 2 /g, preferably a surface area of at least 10 m 2 /g.
• particles containing such a charged organic compound are suitable per se as a catalyst for depolymerisation, but also result in removal of colourants from a typically aqueous product stream comprising monomer.
• the colourant molecules are attracted to the positively charged organic group.
• the particles may act as substrates onto which solidification of the oligomers and/or any polymers occurs. The colour is then trapped into the solid phase. It is observed that the said particles with color removal groups attached thereto may further contribute to the degradation of the polymer.
• the catalyst composition comprises a ionic liquid.
• a ionic liquid suitable contains a charged organic compound of the type identified hereinabove and any counterion.
• the addition of a ionic liquid to the composition, wherein it is dissolved into the alcoholic carrier liquid is understood to contribute to colour removal.
• the catalyst composition further comprises a dispersing agent.
• Such a dispersing agent is suitable to prevent any adhesion of the particles to each other.
• a dispersing agent that is not charged and does not use counter-ions, so as to keep the concentration of ions as low as possible.
• the use of dispersing agents with one or more anchoring sites for adsorption to the particle surface and one or more stabilizing groups extending into the carrier liquid is deemed preferred. Suitable stabilizing groups include for instance
• oligo(alkyleneoxides) wherein alkylene is ethylene, propylene and/or butylenes.
• Suitable groups for anchoring include carboxylic acids groups, silanol-groups, for instance derived from TEOS.
• Fig. 1 shows a graph of the conversion of polyethylene terephthalate (PET) in solid form to monomer (BHET) as a function of time for different catalysts.
• PET polyethylene terephthalate
• BHET monomer
• Catalyst 1 was the catalyst as described in non- pre-published application NL2017033, which is included herein by reference.
• the catalyst comprises 100-200 nm aggregates of magnetite nanoparticles of lOnm diameter, onto which were grafted a combination of a 3-[butyl-imidazolium]-propyl-triethoxysiIane. In the grafting process, one or more of the ethoxy-groups were removed to obtain a silanol-bond.
• AH catalysts were used in a ratio of lwt% catalyst relative to the polyethylene terephthalate (PET).
• PET polyethylene terephthalate
• the PET was provided was PET flakes with an average size of about 1x0.5 cm.
• the PET flakes were prepared from transparent PET bottles.
• the PET flakes were weighted to obtain a 12 wt% dispersion in ethylene glycol.
• Catalyst compositions were prepared by dispersing the catalyst into ethylene glycol so as to provide dispersions of 10wt%.
• the catalyst dispersion was homogenised by shaking vigorously for 5 minutes by hand. Thereafter, further ethylene glycol was added to dilute the catalyst composition to the desired density. Then, the PET flakes were added and the round bottom flask was placed in the heating set up.
• Catalyst 3a was used in a ratio of 1 wt% relative to the PET, in the manner as identified in Example 1 , and on labscale. After the predefined depoiymerisation time, the reaction mixture was cooled down by adding water. This further resulted in solidification of oligomers. The solids were thereafter separated from the liquid by means of a magnet. I.e. A magnet was applied at an outside of a reaction vessel in the form of a glass beaker. The iron particles were thereafter reused as a catalyst without any further processing or purification. It was found that the iron particles could be reused at least 20 times without loss of catalytic activity.

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• 2017
  • 2017-01-31 NL NL2018269A patent/NL2018269B1/en not_active IP Right Cessation
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