GB2447268A - Process for polymerisation of a cyclic monomer - Google Patents

Process for polymerisation of a cyclic monomer Download PDF

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GB2447268A
GB2447268A GB0704242A GB0704242A GB2447268A GB 2447268 A GB2447268 A GB 2447268A GB 0704242 A GB0704242 A GB 0704242A GB 0704242 A GB0704242 A GB 0704242A GB 2447268 A GB2447268 A GB 2447268A
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cyclic
compound
catalyst
zirconium
metal
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Barbara Iacono
Matthew David Gwydion Lunn
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Johnson Matthey PLC
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Johnson Matthey PLC
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    • 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
    • B01J31/00—Catalysts comprising hydrides, coordination complexes or organic compounds
    • B01J31/02—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides
    • B01J31/0201—Oxygen-containing compounds
    • 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
    • B01J31/00—Catalysts comprising hydrides, coordination complexes or organic compounds
    • B01J31/02—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides
    • B01J31/0201—Oxygen-containing compounds
    • B01J31/0211—Oxygen-containing compounds with a metal-oxygen link
    • B01J31/0212—Alkoxylates
    • 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
    • B01J31/00—Catalysts comprising hydrides, coordination complexes or organic compounds
    • B01J31/02—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides
    • B01J31/04—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides containing carboxylic acids or their salts
    • 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
    • B01J31/00—Catalysts comprising hydrides, coordination complexes or organic compounds
    • B01J31/26—Catalysts comprising hydrides, coordination complexes or organic compounds containing in addition, inorganic metal compounds not provided for in groups B01J31/02 - B01J31/24
    • B01J31/38—Catalysts comprising hydrides, coordination complexes or organic compounds containing in addition, inorganic metal compounds not provided for in groups B01J31/02 - B01J31/24 of titanium, zirconium or hafnium
    • 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
    • C08G63/02—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds
    • C08G63/12—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds derived from polycarboxylic acids and polyhydroxy compounds
    • C08G63/40—Polyesters derived from ester-forming derivatives of polycarboxylic acids or of polyhydroxy compounds, other than from esters thereof
    • C08G63/42—Cyclic ethers; Cyclic carbonates; Cyclic sulfites; Cyclic orthoesters
    • 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
    • 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
    • C08G63/85—Germanium, tin, lead, arsenic, antimony, bismuth, titanium, zirconium, hafnium, vanadium, niobium, tantalum, or compounds thereof
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L67/00—Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Compositions of derivatives of such polymers
    • C08L67/06—Unsaturated polyesters
    • 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
    • B01J2231/00—Catalytic reactions performed with catalysts classified in B01J31/00
    • B01J2231/10—Polymerisation reactions involving at least dual use catalysts, e.g. for both oligomerisation and polymerisation
    • B01J2231/14—Other (co) polymerisation, e.g. of lactides or epoxides
    • 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
    • B01J2531/00—Additional information regarding catalytic systems classified in B01J31/00
    • B01J2531/30—Complexes comprising metals of Group III (IIIA or IIIB) as the central metal
    • B01J2531/31—Aluminium
    • 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
    • B01J2531/00—Additional information regarding catalytic systems classified in B01J31/00
    • B01J2531/40—Complexes comprising metals of Group IV (IVA or IVB) as the central metal
    • B01J2531/46—Titanium
    • 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
    • B01J2531/00—Additional information regarding catalytic systems classified in B01J31/00
    • B01J2531/40—Complexes comprising metals of Group IV (IVA or IVB) as the central metal
    • B01J2531/48—Zirconium
    • 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
    • B01J2531/00—Additional information regarding catalytic systems classified in B01J31/00
    • B01J2531/40—Complexes comprising metals of Group IV (IVA or IVB) as the central metal
    • B01J2531/49—Hafnium

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Organic Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Polyesters Or Polycarbonates (AREA)

Abstract

A process for polymerising a cyclic monomer comprises the step of forming a mixture of the monomer with a catalyst compound wherein the catalyst compound comprises a reaction product of a reactive titanium, zirconium, hafnium or aluminium compound with a hydroxycarboxylic acid or derivative thereof, with a proviso that when the cyclic monomer has more than five carbon atoms in the ring the catalyst does not comprise a Group IVB metal lactate of general formula M(OCH(CR3)CO2H)2(OH)2, where M is a Group IVB metal, or its aqueous solution or alkali-neutralised salt. The catalyst may comprise a compound having the general formula aM(L)b(OR)(av)-(bw), where OR is an alkoxide, L is a fully or partially deprotonated, optionally derivatised, hydroxycarboxylic acid ligand, M represents a metal selected from titanium, zirconium, hafnium or aluminium, a is the number of metal atoms, v is a number equal to the valency of the metal M, b is a number from 1 to a times v and w is the number of deprotonated groups on each hydroxycarboxylic acid ligand. Also disclosed is a polymerisable mixture comprising at least one cyclic carbonate, cyclic carbamate, lactide, cyclic lactone or other cyclic compound containing two heteroatoms and 5 or fewer carbon atoms, and a catalyst formed from the reaction of a titanium, zirconium, hafnium or aluminium compound with a hydroxycarboxylic acid or derivative thereof, such as lactic acid or an ester of lactic acid.

Description

Polymerisation Reaction and Catalyst Therefor This application concerns
catalyst compositions, for use as catalysts for the ring-opening polymerisation of certain oxygen-and nitrogen-containing cyclic compounds, polymerisable mixtures containing these catalyst compositions, methods for their preparation and methods of carrying out ring-opening polymerisation reactions using the catalyst compositions of the invention.
Ring-opening polymerisations are an important route to polylactides and other materials, which are useful for example as biocompatible and biodegradable polymers. Conventional ring-opening polymerisations are carried out using a catalyst such as tin octanoate However in these systems it has been difficult to obtain a polymer having a narrow molecular weight distribution (as indicated by a low polydispersity M/M) Furthermore the use polyesters containing tin compounds to make biocompatible articles may be less favoured, see Dobrzynski et al Journal of Biomedical Materials Research Part A (2005) vol 74A, issue 4, page 591 -597.
Chisholm eta! (J. Am. Chem. Soc. 2000, 122, 11845 -11854) have described the formation of polylactides by ring-opening polymerisation using magnesium and zinc alkoxides with trispyrazolyl and trisindazolylborate ligands Kim and Verkade describe the formation of polylactides by ring-opening polymerisation using titanatranes (Organometallics, 2002, 21, 2395-2399). EP-A-0710685 describes the preparation of biodegradable aliphatic polyesters prepared by polycondensing cyclic acid anhyd rides with cyclic ethers in the presence of ring-opening polymerisation catalysts such as alkoxyzirconium compounds or oxyzirconium salts.
US2878236 describes the production of lactone polyesters using group IV metal chelates, including metal lactates and glycolates as catalysts for lactone polymerisation. These catalyst types are stated to be unsuitable for the polymerisation of lactones having five or fewer carbon atoms in the ring due to depolymerisation of the polymers at elevated temperature.
Surprisingly, despite these difficulties mentioned in US2878236, we have discovered that group IV metal chelates of hydroxyacids and their derivatives are effective catalysts for the polymerisation of cyclic monomers containing two heteroatoms and 5 or fewer carbon atoms in the ring.
It is an object of the present invention to provide a catalyst system, which does not contain tin, for ring-opening polymerisation reactions of cyclic monomers, including, but not limited to, cyclic monomers containing 5 or fewer carbon atoms in the ring. It is a further object of the invention to provide novel compositions that are useful as catalysts and a method for their manufacture.
According to the invention, we provide a compound suitable for use as a catalyst for the ring-opening polymerisation of a cyclic monomer, the catalyst comprising a compound formed from the reaction of a reactive titanium, zirconium, hafnium or aluminium compound with a hydroxycarboxyli c acid or derivative thereof.
According to a second aspect of the invention, we provide a process for the polymerisation of a cyclic monomer comprising the step of forming a mixture of said monomer with a catalyst compound and maintaining conditions of temperature and pressure sufficient to enable the formation of a polymer, characterised in that the catalyst compound comprises a reaction product of a reactive titanium, zirconium, hafnium or aluminium compound with a hydroxycarboxylic acid or derivative thereof According to a further aspect of the invention we provide a polymerisable mixture comprising at least one cyclic carbonate, cyclic carbarnate, cyclic lactone, lactide, or other cyclic compound which is susceptible to ring-opening polymerisation, and a catalyst comprising a compound formed from the reaction of a reactive titanium, zirconium, hafnium or aluminium compound with a hydroxycarboxylic acid or derivative thereof The catalyst compound is especially useful as a catalyst for the ring opening polymerisation of a cyclic carbonate, cyclic carbamate, lactide, cyclic lactone, or other cyclic compound which is susceptible to ring-opening polymerisation, especially for synthesis of polyesters, polyamides, and polyurethanes When the cyclic monomer contains more than five carbon atoms in the ring the catalyst does not comprise a Grp IVB metal lactate of general formula M(OCH(CH3)CO2H)2(OH)2 or its aqueous solution or alkali-neutralised salt as described in US2878236, where M is a Grp IVB metal The reactive titanium, zirconium, hafnium or aluminium compound is preferably selected from an alkoxide, a condensed alkoxide, a halide, haloalkoxide, amide or oxyhalide; although other compounds may also be used.
An alkoxide of titanium, zirconium, hafnium or aluminium has the formula M(OR) where M represents the metal, R is an alkyl group, and v = 3 or 4 according to the valency of the metal M. Each R is preferably the same but may be different from one or each other R More preferably, R contains 1 to 8 carbon atoms and particularly suitable alkoxides include tetra-methoxytitanium, tetra-ethoxytitaniurn, tetra-isopropoxytitanium, tetra-n-propoxytitani urn, tetrabutoxytitani urn, tetraethyl hexyltita ni urn, tetra-propoxyzircon i urn, tetra-isopropoxyzirconium tetra-butoxyzircon urn, tetra-n-propoxyhafniurn, tetra-n-butoxyhafniurn and triisopropoxyaluminium Condensed alkoxides of titanium, zirconium or hafnium can be represented by the general formula RO{M(OR)2O] R, wherein M and R have the same meaning as discussed above and n is an integer Generally, these condensed alkoxides consist of a mixture containing compounds of the above formula with n having a range of values Preferably n has an average value in the range 2 to 16 and, more preferably, in the range 2 to 8. A condensed alkoxide is usually prepared by the controlled addition of water to an alkoxide, followed by removal of alcohol which is displaced. Suitable condensed alkoxides include the compounds known as polybutyl titanate, polybutyl zirconate and polyisopropyl titanate Halides and mixed halo-alkoxides of titanium, zirconium and hafnium can be represented by the general formula MX (OR) wherein X is a halogen atom, preferably Cl M and R have the same meaning as discussed above, x is a positive integer having a value of 1,2,3 or 4 and v is trie valency of the metal Preferred metal oxyhalides comprise titanium, zirconium, hafnium or aluminium oxychlorides, especially zirconium oxychloride Preferably, the reactive titanium zirconium, hafnium or aluminium compound is a titanium or zirconium compound, and most preferably it is a zirconium compound. Preferably, the titanium zirconium, hafnium or aluminium compound is an alkoxide.
The hydroxycarboxylic acid or derivative thereof is preferably, though not exclusively, from the group; lactic acid, tartaric acid, malic acid and citric acid Preferred derivatives are esters, although other derivatives, such as amides, may be used. Preferred esters are esters of lactic acid, i e lactates. Suitable hydroxycarboxylic esters include alkyl lactates, particularly lactates of alcohols having up to 8 carbon atoms, for example isopropyl lactate and ethyl lactate.
The hydroxyacid may react with the metal compound through its hydroxyl group (or one or more of them if the hydroxyacid contains more than one hydroxyl group), forming a functionalised alkoxide, or through a carboxylic acid group to form a metal carboxylate. Where the hydroxyacid contains more than one reactive group, i.e. at least one hydroxyl group and at least one carboxylic acid group, more than one hydroxyl group and/or more than one carboxylic acid group, the product of the reaction between the hydroxyacid and the metal compound is likely to comprise a mixture of compounds. The mixture of compounds may compounds containing a single metal atom and compounds containing more than one metal atom. This is because where the hydroxyacid contains more than one reactive group, each reactive group may react with a different metal atom, forming a bridge between the metal atoms. Thus the catalyst compounds formed from the hydroxyacids are very likely to be mixtures of a number of different compounds. When an ester of a hydroxyacid is used, the carboxylic acid groups are not available for reaction with the metal compound and so the resulting product contains functionalised alkoxide groups. If the hydroxyacid ester contains more than one reactive hydroxyl groups then the product may contain a mixture of compounds, some of which may include more than one metal atom, for the reasons set out above The catalyst compound preferably comprises a compound having the general formula aM(L)b(OR)(av)(bw), where OR is an alkoxide, L is a fully or partially deprotonated, optionally derivitised, hydroxycarboxylic acid ligand, M represents a metal selected from titanium, zirconium, hafnium or aluminium, a is the number of metal atoms, v is a number equal to the valency of the metal M, b is a number from 1 to a times v and w is the number of deprotonated groups on each hydroxycarboxylic acid ligand The catalyst compound is preferably a compound having either the general formula M(L')b(OR)v..b, where OR represents an alkoxide, L' represents a deprotonated hydroxyacid ester, M represents titanium or zirconium and b is 2, 3 or 4; or the general formula M(L")2 where L" is a deprotonated hydroxyacid and M preferably represents titanium or zirconium. L' is preferably a lactate ester and L' is preferably lactate.
The cyclic compound which is susceptible to ring-opening polymerisation, (monomer) used is a heterocyclic compound, having at least one oxygen-or nitrogen-containing ring containing two heteroatoms and less than six carbon atoms, which is susceptible to ring-opening polymerisation. These heteroatoms are preferably oxygen or nitrogen, and more preferably oxygen. Examples of such compounds include lactides, carbonates and carbamates such as; lactide, DL dilactide, diglycolide; cyclic carbonates such as propylene carbonate, 2-methyl-i,3-propane diol carbonate; and cyclic carbamates, including substituted carbamates and cyclic lactones such as caprolactone. Co-polymers produced by ringopening polymerisation of one or more one of these monomers with the same type or a different type of monomer not necessarily described herein e g. a lactone-lactide polymer may be made by the process of the invention. One preferred monomer is lactide. The process is especially useful for making block-copolymers because the ring-opening polymerisation using the catalysts of the invention is a living polymerisation system. Other types of copolymer may also be made by this method The catalyst complexes are normally viscous liquids or waxy solids at room temperature. They are normally added to the polymerisable cyclic compound neat, i.e. undiluted, although they may be added in a solvent or diluent if required The complex catalysts are effective at concentrations below 1% by weight based on the metal. The amount of catalyst used in the polymerisation is generally within the range from 0.001 to 1% by weight based on the titanium, zirconium, hafnium or aluminium in the catalyst complex.
The complexes of titanium, zirconium, hafnium or aluminium are made by mixing together the metal compound with a solution of the selected hydroxycarboxylate The mixture may be heated, in particular to remove solvent, and by-products if required When the metal compound is a metal alkoxide, reaction with one mole of the hydroxycarboxylate liberates one or more moles of alcohol, which may be removed by distillation or evaporation if required. However, if the metal compound is a chloride or oxychioride a base may be added to aid the reaction and the resulting chloride salt removed by filtration The formed complex may be used as a catalyst without further purification steps Appropriate measures should be taken to avoid so far as possible degradation, hydrolysis or other deleterious side-reactions. For example, where a metal alkoxide is used, it should be handled in dry conditions under a suitable dry atmosphere to avoid hydrolysis of the metal alkoxide. Normally distillation conditions should be mild, e g distillation under reduced pressure is preferred The skilled person is acquainted with the various methods used and the precautions necessary for the particular reactants selected.
The ring-opening polymerisation reaction is performed using standard methods known in the art. The reactions may proceed in the presence of an initiator, e.g. an alcohol, however, using the catalysts of the invention a separate initiator is not always required. The reaction may be quenched using acetic acid, water or other suitable compound. The reactions are living polymerisation systems and may, if unquenched, be resumed upon addition of further monomer, which may be different to the first monomer, leading to the generation of a block copolymer.
The ring-opening polymerisation reactions may be carried out in a solvent such as toluene, benzene, other aromatic solvent, hexane, heptane, aliphatic hydrocarbons, halogenated hydrocarbons, ethers, or other suitable solvent for the type of monomer and conditions used.
The reaction conditions are selected to be suitable for the particular reaction to be carried out.
The reaction is generally carried out at a temperature in the range from about 10 C to 250 C, but higher or lower temperatures may be used if required.
The invention will be demonstrated in the following examples.
ExamDle 1 Synthesis of Zr(isopropyl-lactate)4 1192 g of isopropyl-lactate (0 00902 mol) was added to 50 ml of anhydrous toluene, lg of VERTECTM NPZ (74% tetra-n-propoxy zirconium in n-propanol, 0.00225 mol) is added The resulting solution is heated with a hot-gun until the boiling toluene turns yellow Then the volatiles, including solvent and propanol released from the reaction, were distilled off under reduced pressure using a liquid nitrogen trap The product obtained, a yellow oily compound, was stored under nitrogen The product was used as a catalyst without further purification.
Examrle 2 Synthesis of Zr(isopropyl-lactate)3(n-propoxide) 0 894 g of isopropyl-lactate (0 0067 mol) was put in a Schlenk round bottomed flask and purged with nitrogen and then a vacuum, the purging cycles being repeated three times 1 g of VERTECTM NPZ was added under flushing nitrogen. The flask was then heated in a preheated oil bath at 130 C for 15 minutes under vacuum. The product obtained was a deep red oily compound which appeared slightly moisture sensitive It was stored under nitrogen The product was used as a catalyst without further purification.
ExamDle 3 Melt-polymerisation of L lactide L lactide was purified by sublimation under nitrogen atmosphere twice at 95-100 C under vacuum and then finally more slowly at 90-95 The sublimation apparatus and glass storage jars were all prepared by heating overnight in an oven at 120 C. The purified lactide was stored in a sealed jar in a glovebox In a glovebox, a 50 ml Schienk round bottomed flask was charged with 1 g of purified L lactide (0 00699 mol) and an amount of catalyst corresponding to a ratio of (moles of lactide)/ (moles of metal) =100 The mixture was put under a small nitrogen flux with an overhead stirrer in a preheated oil bath at 160 C. When the monomer was completely molten, the temperature was increased to 185-190 C and maintained for 20 minutes The mixture was then allowed to cool and the resulting polymer dissolved in dichloromethane and precipitated with methanol. The white suspension of precipitated polymer was separated from the supernatant by centrifuge and the solid polymer obtained was dried overnight in a ventilated oven at 120C The product was analysed by NMR and gel permeation chromatography Results are shown in the Table Table 1: Average molecular weights of Dolymer from Example 3 by GPC Catalyst complex Mn Mw PDI Example 1 10800 11600 1.08 Example 2 12100 13500 111 Example 4 Solution polymerisation of L-lactide A polymerisation of lactide was carried out in toluene solution at 80 C using the catalyst made in Example 1. 0 050 g (3 46*104 mol)of lactide and the amount of catalyst corresponding to a lactide/catalyst metal ratio of between 40 and 50 were mixed together with deuterated toluene in a 5 mm NMR tube. The tube was quickly transferred to an NMR spectrometer. A first spectrum was performed a at room temperature as a reference and then the temperature of the probe was increased to 80 C and the NMR spectrum was then recorded every 5 minutes. The conversion of lactide monomer to polymer was estimated from the 400 MHz (1H NMR toluene d8 at 80 C) methine CH signal of the monomer (q, 4 ppm) and the polymer(q, 5.15 ppm) The results are shown in Table 2 Table 2: Conversion of lactide in toluene d8 at 80 C using Zr(isoproDyl-lactate)4 Time (mm) 5 10 15 20 25 30 45 Conversion % 25 43 57 67 75 81 91

Claims (6)

  1. Claims 1 A process for the polymerisation of a cyclic monomer,
    comprising the step of forming a mixture of said monomer with a catalyst compound and maintaining said mixture under conditions of temperature and pressure sufficient to enable the formation of a polymer, characterised in that the catalyst compound comprises a reaction product of a reactive titanium, zirconium, hafnium or aluminium compound with a hydroxycarboxylic acid or derivative thereof, provided that when the cyclic monomer contains more than five carbon atoms in the ring the catalyst does not comprise a Grp IVB metal lactate of general formula M(OCH(CH3)CO2H)2(OH)2, where M is a Grp IVB metal, or its aqueous solution or alkali-neutralised salt
  2. 2 The process claimed in claim 1, wherein said cyclic monomer comprises a cyclic carbonate, cyclic carbamate, cyclic lactone or lactide
  3. 3 The process claimed in claim 1 or claim 2, wherein said titanium, zirconium, hafnium or aluminium compound is selected from an alkoxide, a condensed alkoxide, a halide, haloalkoxide, amide or oxyhalide
  4. 4. The process claimed in any one of the preceding claims, wherein the hydroxycarboxylic acid or derivative thereof is lactic acid or a derivative of lactic acid.
  5. The process claimed in any one of the preceding claims, wherein the hydroxycarboxylic acid or derivative thereof is an ester of lactic acid.
  6. 6. The process claimed in any one of the preceding claims, wherein the catalyst comprises a compound having the general formula aM(L)b(OR)(av)(bw), where OR is an alkoxide, L is a fully or partially deprotonated, optionally derivitised, hydroxycarboxylic acid ligand, M represents a metal selected from titanium, zirconium, hafnium or aluminium, a is the number of metal atoms, v is a number equal to the valency of the metal M, b is a number from 1 to a times v and w is the number of deprotonated groups on each hydroxycarboxylic acid ligand 7 The process claimed in claim 6, wherein b is a number in the range from 2 -4 8 The process claimed in claim 6 or claim 7, wherein M represents titanium or zirconium 9 A polymerisable mixture comprising at least one cyclic carbonate, cyclic carbamate, lactide, cyclic lactone, or other cyclic compound containing two heteroatoms and 5 or fewer carbon atoms which is susceptible to ring-opening polymerisation, and a catalyst formed from the reaction of a titanium, zirconium, hafnium or aluminium compound with a hydroxycarboxylic acid or derivative thereof.
    A polymerisable mixture as claimed in claim 9, wherein the hydroxycarboxylic acid or derivative is lactic acid or an ester of lactic acid 11. A polymerisable mixture as claimed in claim 9 or claim 10, wherein the catalyst comprises a compound having the general formula aM(L)b(OR)(av)(bw), where OR is an alkoxide, L is a fully or partially deprotonated, optionally derivitised, hydroxycarboxylic acid ligand, M represents a metal selected from titanium, zirconium, hafnium or aluminium, a is the number of metal atoms, v is a number equal to the valency of the metal M, b is a number from 1 to a times v and w is the number of deprotonated groups on each hydroxycarboxylic acid ligand.
    12 A polymerisable mixture as claimed in claim 11, wherein b isa number in the range from 2 to 4 13 A polymerisable mixture as claimed in claim 11 or claim 12, wherein M represents titanium or zirconium
GB0704242A 2007-03-06 2007-03-06 Process for polymerisation of a cyclic monomer Withdrawn GB2447268A (en)

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CZ305870B6 (en) * 2014-12-18 2016-03-23 Univerzita Pardubice Process for preparing biodegradable polymers, biodegradable polymers and their use

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US5616681A (en) * 1994-11-01 1997-04-01 Nippon Shokubai Co., Ltd. Process for producing aliphatic polyester
US20030203811A1 (en) * 2002-04-25 2003-10-30 Putzig Donald Edward Stable aqueous solutions comprising titanium and zinc and process therewith
US20060155102A1 (en) * 2002-12-04 2006-07-13 Lindall Charles M Catalyst and process

Patent Citations (3)

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US5616681A (en) * 1994-11-01 1997-04-01 Nippon Shokubai Co., Ltd. Process for producing aliphatic polyester
US20030203811A1 (en) * 2002-04-25 2003-10-30 Putzig Donald Edward Stable aqueous solutions comprising titanium and zinc and process therewith
US20060155102A1 (en) * 2002-12-04 2006-07-13 Lindall Charles M Catalyst and process

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CZ305870B6 (en) * 2014-12-18 2016-03-23 Univerzita Pardubice Process for preparing biodegradable polymers, biodegradable polymers and their use

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