WO2004014889A1 - Procede de production de polylactide au depart d'une solution d'acide lactique ou d'un de ses derives. - Google Patents
Procede de production de polylactide au depart d'une solution d'acide lactique ou d'un de ses derives. Download PDFInfo
- Publication number
- WO2004014889A1 WO2004014889A1 PCT/EP2003/050360 EP0350360W WO2004014889A1 WO 2004014889 A1 WO2004014889 A1 WO 2004014889A1 EP 0350360 W EP0350360 W EP 0350360W WO 2004014889 A1 WO2004014889 A1 WO 2004014889A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- lactide
- lactic acid
- oligomers
- purified
- crystallization
- Prior art date
Links
- JVTAAEKCZFNVCJ-UHFFFAOYSA-N lactic acid Chemical compound CC(O)C(O)=O JVTAAEKCZFNVCJ-UHFFFAOYSA-N 0.000 title claims abstract description 130
- 239000004310 lactic acid Substances 0.000 title claims abstract description 60
- 235000014655 lactic acid Nutrition 0.000 title claims abstract description 60
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 37
- 229920000747 poly(lactic acid) Polymers 0.000 title claims abstract description 32
- 238000000034 method Methods 0.000 title claims description 81
- JJTUDXZGHPGLLC-UHFFFAOYSA-N lactide Chemical compound CC1OC(=O)C(C)OC1=O JJTUDXZGHPGLLC-UHFFFAOYSA-N 0.000 claims abstract description 206
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 66
- 238000002425 crystallisation Methods 0.000 claims abstract description 58
- 230000008025 crystallization Effects 0.000 claims abstract description 58
- 239000003054 catalyst Substances 0.000 claims abstract description 49
- 238000006116 polymerization reaction Methods 0.000 claims abstract description 28
- 238000001704 evaporation Methods 0.000 claims abstract description 17
- 230000008020 evaporation Effects 0.000 claims abstract description 17
- 238000009833 condensation Methods 0.000 claims abstract description 15
- 230000005494 condensation Effects 0.000 claims abstract description 15
- 239000007864 aqueous solution Substances 0.000 claims abstract description 12
- 230000008569 process Effects 0.000 claims description 61
- 239000013078 crystal Substances 0.000 claims description 56
- 239000000203 mixture Substances 0.000 claims description 56
- 238000000746 purification Methods 0.000 claims description 45
- 239000012535 impurity Substances 0.000 claims description 40
- 239000007791 liquid phase Substances 0.000 claims description 30
- 239000007788 liquid Substances 0.000 claims description 29
- JJTUDXZGHPGLLC-ZXZARUISSA-N (3r,6s)-3,6-dimethyl-1,4-dioxane-2,5-dione Chemical compound C[C@H]1OC(=O)[C@H](C)OC1=O JJTUDXZGHPGLLC-ZXZARUISSA-N 0.000 claims description 22
- 238000000605 extraction Methods 0.000 claims description 18
- 239000000725 suspension Substances 0.000 claims description 16
- 150000001875 compounds Chemical class 0.000 claims description 13
- 230000003287 optical effect Effects 0.000 claims description 13
- JVTAAEKCZFNVCJ-REOHCLBHSA-N L-lactic acid Chemical compound C[C@H](O)C(O)=O JVTAAEKCZFNVCJ-REOHCLBHSA-N 0.000 claims description 12
- 239000012808 vapor phase Substances 0.000 claims description 12
- 238000001035 drying Methods 0.000 claims description 11
- 238000005204 segregation Methods 0.000 claims description 10
- 238000000926 separation method Methods 0.000 claims description 10
- 239000007790 solid phase Substances 0.000 claims description 10
- 239000012736 aqueous medium Substances 0.000 claims description 9
- 150000003903 lactic acid esters Chemical class 0.000 claims description 8
- 239000002253 acid Substances 0.000 claims description 7
- 239000000945 filler Substances 0.000 claims description 7
- 238000011084 recovery Methods 0.000 claims description 6
- 239000012744 reinforcing agent Substances 0.000 claims description 6
- 238000007142 ring opening reaction Methods 0.000 claims description 6
- 239000003381 stabilizer Substances 0.000 claims description 6
- 230000000977 initiatory effect Effects 0.000 claims description 2
- 230000015572 biosynthetic process Effects 0.000 abstract description 29
- 239000000047 product Substances 0.000 description 37
- 238000006243 chemical reaction Methods 0.000 description 27
- 238000003786 synthesis reaction Methods 0.000 description 21
- 235000019647 acidic taste Nutrition 0.000 description 19
- 238000001953 recrystallisation Methods 0.000 description 16
- 230000007062 hydrolysis Effects 0.000 description 14
- 238000006460 hydrolysis reaction Methods 0.000 description 14
- 238000005516 engineering process Methods 0.000 description 13
- 239000000126 substance Substances 0.000 description 12
- 229920000642 polymer Polymers 0.000 description 10
- 239000012071 phase Substances 0.000 description 9
- 239000000654 additive Substances 0.000 description 8
- 230000006340 racemization Effects 0.000 description 8
- 238000004064 recycling Methods 0.000 description 8
- 230000008901 benefit Effects 0.000 description 7
- 239000002994 raw material Substances 0.000 description 7
- 239000000243 solution Substances 0.000 description 7
- 239000008346 aqueous phase Substances 0.000 description 6
- 230000015556 catabolic process Effects 0.000 description 6
- 238000006731 degradation reaction Methods 0.000 description 6
- LZCLXQDLBQLTDK-UHFFFAOYSA-N ethyl 2-hydroxypropanoate Chemical compound CCOC(=O)C(C)O LZCLXQDLBQLTDK-UHFFFAOYSA-N 0.000 description 6
- 238000006384 oligomerization reaction Methods 0.000 description 6
- KSBAEPSJVUENNK-UHFFFAOYSA-L tin(ii) 2-ethylhexanoate Chemical compound [Sn+2].CCCCC(CC)C([O-])=O.CCCCC(CC)C([O-])=O KSBAEPSJVUENNK-UHFFFAOYSA-L 0.000 description 6
- JJTUDXZGHPGLLC-IMJSIDKUSA-N 4511-42-6 Chemical compound C[C@@H]1OC(=O)[C@H](C)OC1=O JJTUDXZGHPGLLC-IMJSIDKUSA-N 0.000 description 5
- 238000004821 distillation Methods 0.000 description 5
- 230000032050 esterification Effects 0.000 description 5
- 238000005886 esterification reaction Methods 0.000 description 5
- 238000010438 heat treatment Methods 0.000 description 5
- 230000008018 melting Effects 0.000 description 5
- 238000002844 melting Methods 0.000 description 5
- 239000000178 monomer Substances 0.000 description 5
- 230000003068 static effect Effects 0.000 description 5
- 239000003039 volatile agent Substances 0.000 description 5
- 238000013459 approach Methods 0.000 description 4
- 150000002148 esters Chemical class 0.000 description 4
- 239000010408 film Substances 0.000 description 4
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- 230000005484 gravity Effects 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- 238000002156 mixing Methods 0.000 description 4
- 238000010926 purge Methods 0.000 description 4
- 239000007787 solid Substances 0.000 description 4
- RIOQSEWOXXDEQQ-UHFFFAOYSA-N triphenylphosphine Chemical compound C1=CC=CC=C1P(C=1C=CC=CC=1)C1=CC=CC=C1 RIOQSEWOXXDEQQ-UHFFFAOYSA-N 0.000 description 4
- 229930182843 D-Lactic acid Natural products 0.000 description 3
- JVTAAEKCZFNVCJ-UWTATZPHSA-N D-lactic acid Chemical compound C[C@@H](O)C(O)=O JVTAAEKCZFNVCJ-UWTATZPHSA-N 0.000 description 3
- 150000007513 acids Chemical class 0.000 description 3
- 238000004458 analytical method Methods 0.000 description 3
- 239000006227 byproduct Substances 0.000 description 3
- 230000003197 catalytic effect Effects 0.000 description 3
- 239000003795 chemical substances by application Substances 0.000 description 3
- 230000001276 controlling effect Effects 0.000 description 3
- 238000005336 cracking Methods 0.000 description 3
- 229940022769 d- lactic acid Drugs 0.000 description 3
- 229940116333 ethyl lactate Drugs 0.000 description 3
- 239000012467 final product Substances 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 238000000265 homogenisation Methods 0.000 description 3
- 230000002035 prolonged effect Effects 0.000 description 3
- 239000012429 reaction media Substances 0.000 description 3
- 230000035484 reaction time Effects 0.000 description 3
- 229910001220 stainless steel Inorganic materials 0.000 description 3
- 239000010935 stainless steel Substances 0.000 description 3
- 230000008646 thermal stress Effects 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- HEDRZPFGACZZDS-UHFFFAOYSA-N Chloroform Chemical compound ClC(Cl)Cl HEDRZPFGACZZDS-UHFFFAOYSA-N 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 241000255969 Pieris brassicae Species 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 230000002378 acidificating effect Effects 0.000 description 2
- 230000000996 additive effect Effects 0.000 description 2
- 150000001413 amino acids Chemical class 0.000 description 2
- 239000003426 co-catalyst Substances 0.000 description 2
- 229920001577 copolymer Polymers 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 239000007857 degradation product Substances 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 230000008030 elimination Effects 0.000 description 2
- 238000003379 elimination reaction Methods 0.000 description 2
- 238000001125 extrusion Methods 0.000 description 2
- 235000013305 food Nutrition 0.000 description 2
- 238000004508 fractional distillation Methods 0.000 description 2
- 235000011389 fruit/vegetable juice Nutrition 0.000 description 2
- 239000013529 heat transfer fluid Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 239000000155 melt Substances 0.000 description 2
- 125000005474 octanoate group Chemical group 0.000 description 2
- 238000004313 potentiometry Methods 0.000 description 2
- 230000000750 progressive effect Effects 0.000 description 2
- 108090000623 proteins and genes Proteins 0.000 description 2
- 102000004169 proteins and genes Human genes 0.000 description 2
- 230000002829 reductive effect Effects 0.000 description 2
- 239000003507 refrigerant Substances 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
- 238000006884 silylation reaction Methods 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 230000000707 stereoselective effect Effects 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 230000035900 sweating Effects 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- VDZOOKBUILJEDG-UHFFFAOYSA-M tetrabutylammonium hydroxide Chemical compound [OH-].CCCC[N+](CCCC)(CCCC)CCCC VDZOOKBUILJEDG-UHFFFAOYSA-M 0.000 description 2
- 239000010409 thin film Substances 0.000 description 2
- JOXIMZWYDAKGHI-UHFFFAOYSA-N toluene-4-sulfonic acid Chemical compound CC1=CC=C(S(O)(=O)=O)C=C1 JOXIMZWYDAKGHI-UHFFFAOYSA-N 0.000 description 2
- 238000005809 transesterification reaction Methods 0.000 description 2
- 238000012546 transfer Methods 0.000 description 2
- SKEZDZQGPKHHSH-UHFFFAOYSA-J 2-hydroxypropanoate;tin(4+) Chemical compound [Sn+4].CC(O)C([O-])=O.CC(O)C([O-])=O.CC(O)C([O-])=O.CC(O)C([O-])=O SKEZDZQGPKHHSH-UHFFFAOYSA-J 0.000 description 1
- LPEKGGXMPWTOCB-UHFFFAOYSA-N 8beta-(2,3-epoxy-2-methylbutyryloxy)-14-acetoxytithifolin Natural products COC(=O)C(C)O LPEKGGXMPWTOCB-UHFFFAOYSA-N 0.000 description 1
- MRABAEUHTLLEML-UHFFFAOYSA-N Butyl lactate Chemical compound CCCCOC(=O)C(C)O MRABAEUHTLLEML-UHFFFAOYSA-N 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 108010082495 Dietary Plant Proteins Proteins 0.000 description 1
- 239000002841 Lewis acid Substances 0.000 description 1
- 241001465754 Metazoa Species 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- IKHGUXGNUITLKF-XPULMUKRSA-N acetaldehyde Chemical compound [14CH]([14CH3])=O IKHGUXGNUITLKF-XPULMUKRSA-N 0.000 description 1
- 230000003213 activating effect Effects 0.000 description 1
- 239000004480 active ingredient Substances 0.000 description 1
- 150000001299 aldehydes Chemical class 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- 229910052787 antimony Inorganic materials 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 239000001191 butyl (2R)-2-hydroxypropanoate Substances 0.000 description 1
- 150000001720 carbohydrates Chemical class 0.000 description 1
- 235000014633 carbohydrates Nutrition 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 125000002915 carbonyl group Chemical group [*:2]C([*:1])=O 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- 238000012512 characterization method Methods 0.000 description 1
- 230000001112 coagulating effect Effects 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000012790 confirmation Methods 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 239000012809 cooling fluid Substances 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
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- 238000009792 diffusion process Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- ODQWQRRAPPTVAG-GZTJUZNOSA-N doxepin Chemical compound C1OC2=CC=CC=C2C(=C/CCN(C)C)/C2=CC=CC=C21 ODQWQRRAPPTVAG-GZTJUZNOSA-N 0.000 description 1
- 230000004064 dysfunction Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 125000004494 ethyl ester group Chemical group 0.000 description 1
- 230000005496 eutectics Effects 0.000 description 1
- 238000013213 extrapolation Methods 0.000 description 1
- 239000011552 falling film Substances 0.000 description 1
- 238000000855 fermentation Methods 0.000 description 1
- 230000004151 fermentation Effects 0.000 description 1
- 239000000706 filtrate Substances 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 229910001385 heavy metal Inorganic materials 0.000 description 1
- 229920001519 homopolymer Polymers 0.000 description 1
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 1
- 238000010348 incorporation Methods 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 125000001449 isopropyl group Chemical group [H]C([H])([H])C([H])(*)C([H])([H])[H] 0.000 description 1
- 239000011968 lewis acid catalyst Substances 0.000 description 1
- 150000007517 lewis acids Chemical class 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 125000001434 methanylylidene group Chemical group [H]C#[*] 0.000 description 1
- 229940057867 methyl lactate Drugs 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 230000003472 neutralizing effect Effects 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000006911 nucleation Effects 0.000 description 1
- 238000010899 nucleation Methods 0.000 description 1
- 238000010534 nucleophilic substitution reaction Methods 0.000 description 1
- 229920005787 opaque polymer Polymers 0.000 description 1
- 125000002524 organometallic group Chemical group 0.000 description 1
- 238000013021 overheating Methods 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 238000004806 packaging method and process Methods 0.000 description 1
- 230000036961 partial effect Effects 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- 238000006068 polycondensation reaction Methods 0.000 description 1
- 239000003755 preservative agent Substances 0.000 description 1
- 230000002335 preservative effect Effects 0.000 description 1
- 230000000135 prohibitive effect Effects 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- KIWATKANDHUUOB-UHFFFAOYSA-N propan-2-yl 2-hydroxypropanoate Chemical compound CC(C)OC(=O)C(C)O KIWATKANDHUUOB-UHFFFAOYSA-N 0.000 description 1
- 238000011002 quantification Methods 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 230000007928 solubilization Effects 0.000 description 1
- 238000005063 solubilization Methods 0.000 description 1
- 238000009331 sowing Methods 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 230000002194 synthesizing effect Effects 0.000 description 1
- 239000003017 thermal stabilizer Substances 0.000 description 1
- 229910052723 transition metal Inorganic materials 0.000 description 1
- 150000003624 transition metals Chemical class 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
- 230000035899 viability Effects 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- -1 water Chemical class 0.000 description 1
- 238000003809 water extraction Methods 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
- CHJMFFKHPHCQIJ-UHFFFAOYSA-L zinc;octanoate Chemical compound [Zn+2].CCCCCCCC([O-])=O.CCCCCCCC([O-])=O CHJMFFKHPHCQIJ-UHFFFAOYSA-L 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D319/00—Heterocyclic compounds containing six-membered rings having two oxygen atoms as the only ring hetero atoms
- C07D319/10—1,4-Dioxanes; Hydrogenated 1,4-dioxanes
- C07D319/12—1,4-Dioxanes; Hydrogenated 1,4-dioxanes not condensed with other rings
-
- 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
- C08G63/06—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds derived from hydroxycarboxylic acids
-
- 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
- C08G63/06—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds derived from hydroxycarboxylic acids
- C08G63/08—Lactones or lactides
Definitions
- the PLA will find its salvation only as part of a cost price comparable to those currently in force within polymers of petrochemical origin in the commodities sector.
- Gruber et al. envisage an integrated process for the synthesis of PLA starting from a solution (more or less pure) of lactic acid and / or one of its esters comprising: 1. in one or two stages, evaporation of the free water and part of the bound water so as to produce an oligomer with a molecular mass of between 100 and 5000 uma; 2. a mixture of the depolymerization catalyst with the oligomer, followed by a thermo-cracking of the mixture with production of lactide in vapor form;
- O'Brien et al. envisage an integrated process for the synthesis of a purified lactide for PLA starting from an aqueous solution of lactic acid containing at least 50% by weight of lactic acid comprising:
- the invention consists of an integrated low-temperature process for producing and purifying lactide from an aqueous solution of lactic acid or lactic acid derivatives, comprising: a) evaporation free water and part of the water of constitution until oligomers having a molecular mass of between 400 and 2000 uma are obtained, a total acidity in lactic acid equivalent of between 119 and 124.5 % and an optical purity expressed in L-lactic acid of between 90 and 100%; b) a feed of the mixture comprising a depolymerization catalyst and the oligomers obtained in a), in a depolymerization reactor with production of: bl) a vapor phase rich in lactide, and b2) a liquid residue rich in oligomers; c) a selective condensation of the lactide-rich vapor (b1) with recovery
- a second embodiment of the invention consists of an integrated low temperature process for producing and purifying lactide from an aqueous solution of lactic acid or lactic acid derivatives, comprising: a) evaporation of free water and part of the water of constitution until oligomers having a molecular mass of between 400 and 2000 uma are obtained, a total acidity in lactic acid equivalent of between 119 and 124.5% and an optical purity expressed in L-lactic acid of between 90 and 100%; b) a feed of the mixture comprising a depolymerization catalyst and the oligomers obtained in a) in a depolymerization reactor with production of: bl) a vapor phase rich in lactide, and b2) a liquid residue rich in oligomers; c) selective condensation of the lactide-rich vapor
- the invention also proves to be advantageous in the context of a process for the production of polylactide, the phase of production and purification of lactide starting from an aqueous solution of lactic acid or of lactic acid derivatives comprising the steps a) to e3) of the first embodiment above, to which is added a step of polymerization of lactide into polylactide.
- a step of polymerization of lactide into polylactide it is also advantageously possible to add a step of polymerization of lactide into polylactide.
- the process step which consists of an extractive and controlled crystallization in an aqueous medium of lactide fractions, with control of the geometry of the crystals formed and segregation of the lactide suspension towards the solid phase and of the impurities towards the liquid phase so as to carry out an aqueous extraction of the impurities, presents particular characteristics: - this crystallization is carried out with a quantity of water as small as possible (for example 0 to 25%);
- the mixture (lactide + water) will be brought to and kept at a temperature just below its crystallization temperature (eg 5 ° C below);
- the formation of large crystals also promotes the transfer of impurities to the aqueous phase; the formation of large crystals makes it possible to obtain a more effective subsequent separation and subsequent drying.
- These large crystals are an essential indication that the process works under conditions of temperature, time and quantities of water in accordance with the invention: they are a confirmation of the fact that the process is well managed according to the invention .
- These large crystals are formed in conditions opposite to those of mass crystallizations.
- the control of the crystallization, according to the invention is done by a control of the temperature profile: no sudden drop, but obtaining and then maintaining for a certain time of a temperature hardly lower than the crystallization temperature.
- the starting lactic acid derivatives comprise the lactic acid esters or a mixture of lactic acid and one or more lactic acid esters.
- the crude lactide is enriched with prepurified lactide fractions originating from the aqueous treatment of the residual fractions of crystallization in the molten state. Recycling represents an important aspect of carrying out the invention: the pre-purified lactide resulting from the aqueous treatment can be recycled at any level of the production of purified lactide.
- the content of D-lactide is controlled by polymerization by ring opening of the prepurified lactide.
- the pre-purified lactide has a residual water content of between 50 and 1000 ppm, a total lactide content of between 70 and 99%, a content of lactic acid and oligomers d lactic acid between 0 and 5% and a meso-lactide content between 0 and 15%.
- the polymerization of the purified and / or pre-purified lactide comprises the steps: a) of adding a catalyst or mixture of catalysts to the lactide; b) adding optional comonomers, oligomers, prepolymers, stabilizers, fillers, reinforcing agents or polymerization moderators to the mixture (a) during the initiation of the prepolymerization and / or during polymerization in an extruder.
- the polymerization of the purified and / or pre-purified lactide does not require prepolymerization.
- the recycled fractions of lactic acid or its derivatives are introduced at the level of the step of purifying the process for producing lactic acid or its derivatives.
- D-lactic units in low concentration does not constitute a problem for the quality of the final lactide from the moment when they integrate into the process a stereo purification unit. -specific such as for example, crystallization in the molten state (or melt crystallization). However, in the context of an integrated process, this concentration will gradually increase and we will observe a dysfunction of the different stages of the process.
- Another advantage of the low temperature process lies in the possibility, through the extractive recrystallization step in an aqueous medium, of extracting from the main stream the rare D-lactic units generated during the first two steps of the process. Indeed, at the end of this treatment, it is possible to obtain a lactide characterized by a chemical purity sufficient to be able to be used as (co) monomer for the synthesis of PLA but of an optical purity characterized by the joint presence of meso- and L-lactide. This new approach makes it possible to envisage a fully integrated and therefore economically viable process.
- Another innovative aspect of the present invention consists in recycling all or part of the hydrolysed by-products and resulting from the various stages of the process such as the evaporation distillates, the depolymerization residue, the filtrate resulting from the extraction with l water, etc., not directly at the level of the lactide synthesis process, but rather at that of the production of lactic acid and more particularly before the purification steps thereof.
- impurities such as amino acids, proteins, carbohydrates, heavy metals, aldehydes, etc., which is present in small quantities in the starting material and which disturb the good functioning (technical and economical) of the different stages of the process as well as the purity of the final product.
- the starting mixture will be an aqueous solution of lactic acid obtained chemically
- lactic acid concentration can vary from 15 to 100% knowing that the evaporation of this free water will generate additional costs.
- This aqueous solution of lactic acid is concentrated by evaporation so as to first extract the water free and thereafter part of the water of constitution.
- the elimination of this water of constitution is accompanied by the creation of ester bonds, by a so-called polycondensation reaction, which induces the formation of lactic acid oligomers.
- the synthesized oligomers are ideally characterized by a molecular mass between 400 and 2000, a total acidity in lactic acid equivalent between 119 and 124.5% and a D-lactic acid content between 0 and 10%.
- This quality makes it possible, on the one hand, to avoid the problems associated with the transfer of very viscous products and, on the other hand, too high residual acidity in the product obtained at the end of the depolymerization step (synthesis of lactide). Evaporation will be carried out with particular care to avoid on the one hand too much entrainment in lactic unit in the extracted water vapors and on the other hand, to subject the lactic acid and its oligomers to a prolonged thermal stress which would encourage racemization reactions.
- the first consists in promoting the rapid extraction of the volatile compound (water) from the reaction medium, so as to shift the reaction equilibrium towards the formation of the oligomers and thus reduce the reaction time. Vacuum and / or gas flow entrainment of the volatile compound are advantageous options for carrying out this step.
- a second consists in increasing the reaction kinetics and therefore in reducing the reaction time by adding a esterification catalyst.
- the catalysis is of the acid type, different acids can be envisaged. However, it is preferable to take care not to use Lewis type acids (APTS, ZnC12, isopropyl Ti, etc.). Indeed, they act at the level of the hydroxyl group carried by the chiral carbon of lactic acid and therefore can favor the racemization reactions by activating a nucleophilic substitution with inversion of configuration on the methine group.
- protonated acids of the H2S04, H3P04, etc. type can be used, because they act on the oxygen of the carbonyl group, which should in no case favor the racemization reactions.
- the catalyst may be added during the process, that is to say when the residual free acidity of the oligomer will no longer be sufficient to effectively activate the reaction.
- neutralization could be envisaged so as to avoid degradation of the lactide during the depolymerization step.
- reaction kinetics are strongly influenced by the temperature. However, it also promotes racemization reactions which must be avoided at all costs.
- the use of temperatures below 190 ° C and a po.uvant reactor working under vacuum or 'under gas stream and providing a heat exchange surface and a large volume of extraction will solve the problem. Indeed, the large exchange surface will provide the energy required for the reaction in a minimum of time while avoiding overheating while the large extraction volume will promote the elimination of volatile compound (water) and therefore the reaction kinetics.
- different reactors can be interesting alternatives such as, for example, falling film, forced circulation, stirred film evaporators with or without internal condenser, etc.
- This phase of the process could be envisaged in one or more stages in order to optimize the technology vis-à-vis on the one hand the viscosity of the fluxes present, on the other hand the content of lactic acid contained in the distillates and finally in the possible need to add an esterification catalyst in order to revitalize the synthesis.
- the second step consists of a catalytic and thermal depolymerization of the oligomers obtained above so as to produce a vapor phase rich in lactide.
- the use of a catalyst is essential in order to reduce the thermockraking temperature and to avoid chemical and optical deterioration of the synthesized lactide.
- the catalyst will be solid or liquid and of Lewis acid type such as for example tin octoate, tin lactate, antimony octoate, zinc octoate, etc. Its content is between 0.1 and 5 g%.
- Lewis acid catalysts are characterized by a relatively high charge density. However, it has been shown that the latter favor racemization reactions.
- the reactor will be selected so as to maintain the mixture (oligomer / catalyst) the as short as possible (0 to 30 min and preferably 0 to 15 min) at the reaction temperature while providing a large exchange surface and extraction volume.
- the working temperature will be sufficient to initiate the reaction, but not too high to avoid degradation or racemization of the lactide: the temperature will be between 180 and 250 ° C. The optimum temperature will depend on the nature of the starting oligomer (120 to 125%), the nature of the catalyst and the pressure in the system.
- the lactide-rich vapor phase is directly extracted and selectively condensed at the level of a condenser maintained at a well-determined temperature.
- the condenser is maintained at a temperature such that, on the one hand, volatile compounds such as water, most of the lactic acid and products of degradation resulting from the synthesis (acetaldehyde, etc.) remains in the vapor phase (while the lactide and the heavy compounds are condensed) and not too low on the other hand to avoid crystallization of the lactide.
- this temperature will be between 70 and 125 ° C.
- the subsequent stage of the process consists in purifying the crude, in order to obtain a lactide of sufficient chemical and stereospecific purity for the synthesis of PLA by ring opening.
- Sufficient purity implies a lactide content of between 99.0 and 99.9% and preferably still between 99.5 and 99.9%, a meso-LD content of between 0 and 1% and preferably between 0 and 0 , 5%, a water content of between 0 and 200 ppm and preferably between 0 and 50 ppm, and an acidity of between 0 and 10 meq / kg and preferably between 0 and 1 meq / kg.
- the technology of recrystallization in the molten state makes it possible to achieve this quality while working at low temperature.
- the impure lactide obtained above is melted and undergoes controlled cooling to initiate crystallization.
- the impurities will be concentrated in the liquid phase.
- the liquid phase is removed by gravity, leaving crystals coated with a film of impurities.
- an overhaul partial is operated.
- the liquid thus obtained entrains the film and is discharged by gravity. The operation is repeated until the required purity is reached.
- This succession of steps can be of the static and / or dynamic type. Once the desired purity has been reached, the content of the crystallizer is melted and recovered.
- the nature of the impurities present in the initial feed directly influences the efficiency of the purification.
- a more viscous impurity will be more difficult to extract and will require several stages of purification.
- the presence of acidic and aqueous impurities will promote the opening of the lactide cycle, which will have a direct consequence on the yield of the stage.
- the concentration of L-LD in the starting solution makes it possible to significantly improve the mass yield (less impurities to be extracted, less degradation) but also the profitability (fewer purification stages) .
- the theoretical yield of purification by melt crystallization is 78.5%, it increases to 86.4% for a feed containing 90%.
- the factor L-LD concentration in the residue must also be included. Indeed, within the framework of an integrated process, it is preferable to be able to recycle the residue as lactide upstream in the process (to enrich a fraction for example) in order to avoid having to recycle it as units lactic (result of the hydrolysis of lactide) which increases the probability of thermal degradation (increased residence time in the process) and generates significant energy expenditure.
- recrystallization in the molten state can be controlled in a different manner and makes it possible to obtain, for a feed containing 88% of L-LD, a theoretical purification yield of 87% while requiring only one charge. 132 kg feed for 100 kg of finished product. Taking into account these new considerations, it is obvious that this type of technology can, this time, be economically and industrially used without a high temperature pre-purification step.
- the technology enabling the lactide to be recovered from the residue of the recrystallization stage in the molten state will preferably take care of:
- the product resulting from this stage can reach a very high chemical purity and can also contain a certain content in meso-lactide, which constitutes a very interesting method for the extraction of D- units. process lactic.
- the product thus obtained could be used as an additive and mixed with the purified lactide in order to control the content of D-lactic units present and thus play on the properties of the synthesized polymer.
- lactide, purified and pre-purified, synthesized by the process described in the context of this invention can then either be used as an additive for food applications (for example: agent coagulating animal or vegetable proteins, preservative or pH regulator, dough-raising agent in bakery), or be polymerized by ring opening with a wide range of catalysts including organometallic derivatives of transition metals (group 3 to 12) or metals of groups 13 to 15.
- a preferred approach of the present invention considers continuous polymerization of the purified lactide through the addition of the tin octoate / triphenylphosphine binomial in a twin-screw extruder (reactive extrusion). Although a single reactive extrusion step is sufficient to succeed in synthesizing, starting from the lactide, a PLA whose mechanical properties are sufficient to be able to be used in the field of packaging and amenities, this perspective can lead to the following disadvantages:
- the second step will be carried out in a twin-screw extruder.
- the PLA produced within the framework of this invention will be either a homopolymer (for example synthesis starting from pure L-lactide), or a copolymer (for example synthesized starting from lactide containing a proportion of meso-lactide, or of additives) .
- the oligomerization step will imperatively require the use of an acid transesterification catalyst of para-toluenesulfonic acid (APTS) type, octoate d , tin, sulfuric acid, etc. 3.
- APTS para-toluenesulfonic acid
- octoate d octoate d
- tin tin
- sulfuric acid etc. 3.
- the process described considers only the L isomer of lactic acid, but it is obvious that it can also be taken into account for the other isomer, namely D-lactic acid.
- a preferred description of the process which is the subject of the present invention is described below with reference to FIG. 1.
- the aqueous lactic acid solution is supplied by line 1 and can be continuously mixed with the hydrolyzed juice supplied by line 2001 and coming from the hydrolysis tank 2000.
- a preferential option consists in recycling the hydrolyzed juice directly at the stages of purification of the lactic acid production process via the 2002 line so as to be able to remove impurities such as amino acids, proteins, metal ions, etc.
- a hydrolysis residue preferably in solid form, can be extracted via the 2003 line, which makes it possible to purge the system of insoluble matter.
- the hydrolysis tank is only shown diagrammatically by a tank, but several tanks can be envisaged depending on the concentration and the destination of the recycled fractions.
- the mixture is fed continuously via line 2 into a preheater 100 which brings the mixture to the temperature required for the evaporation of water, that is to say between 50 and 150 ° C. It is possible to continuously add to the mixture, via line 121, an esterification catalyst stored in the tank 120. When adding a catalyst, the preheater 100 will preferably be designed so as to be able to heat and homogenize The mixture. In one evaporator 200 which can work under vacuum, at atmospheric pressure or under slight pressure, the most of the free water and part of the water of constitution is continuously extracted in vapor form via line 202 and condensed 210.
- the latter are sent either to the tank d hydrolysis 2000 via line 211, either as water make-up at the level of the extractive crystallization tank 700 via line 212 or, quite simply eliminated via line 213.
- the concentrated lactic acid continuously extracted via line 201 and characterized by an average molecular weight of between 100 and 600 is fed continuously into a preheater 250 which brings the concentrated lactic acid to the oligomerization temperature, that is to say between 80 and 180 ° C. It is possible to add to the mixture, via line 261, an esterification catalyst stored in the tank 260.
- the preheater 250 will preferably be designed so as to be able to heat and homogenize The mixture.
- oligomerization reactor 300 which can work under vacuum, at atmospheric pressure or under slight pressure, a little free water and a majority of water of constitution is extracted in vapor form via line 302 and condensed 310.
- the condensates are sent to the hydrolysis tank 2000 via line 311. This step will preferably be carried out under vacuum without, however, reaching a pressure below 40 mbar absolute so as to accelerate the reaction kinetics and reduce the working temperature while avoiding production too much of the cyclic dimer.
- the oligomers extracted, via line 301, and characterized by a molecular mass of between 600 and 2000 are fed continuously into a preheater / mixer 400.
- This preheater / mixer allows the homogenization of the continuously supplied depolymerization catalyst, at a concentration ranging from 0.2 to 5%, via line 521 and stored in tank 520 and, to bring the mixture of catalyst oligomers to a temperature between 150 and 250 ° C (the exact temperature being a function of the molecular weight of the oligomers). It is possible that a neutralizing agent must be added to the oligomers in order to interrupt the activity of the esterification catalyst before incorporation of the depolymerization catalyst, but this step has not been represented in FIG. 1. It is also it is possible that the catalyst added at the oligomerization stage is suitable for the “back biting” reaction and in this context, any addition of catalyst is less, even superfluous.
- the catalytic depolymerization reactor 500 which is supplied via line 401 with an oligomer / catalyst mixture is controlled so as to promote the “back biting” reaction which generates the lactide.
- the temperature will be between 180 and 250 ° C, the pressure between 0.1 and 40 mbar absolute and the residence time of the mixture under the reaction conditions between 0 and 30 min, preferably between 0 and 15 min.
- a liquid residue (at working temperature) rich in oligomers is extracted from the depolymerization reactor 500, which is sent via line 502 to the hydrolysis tank 2000 and, on the other hand, a vapor phase rich in lactide via line 501.
- the liquid residue collected at the bottom of the reactor is characterized by an average molecular mass equal to or greater than that of the starting mixture 401 and by a catalyst concentration higher than that of the starting mixture 401.
- the vapor phase extracted at the head of the reactor 500 and rich in lactide 501 is selectively condensed at the level of a condenser 510 so as to maintain the volatile compounds such as water, lactic acid and degradation products resulting from the synthesis, etc, in vapor form 513 and to recover the lactide and the heavier compounds in liquid form (crude lactide) 511.
- the crude lactide is characterized by an L-LD content greater than 85% or even 90%, a low meso-LD content of less than 7% or even 5% and even 3% and a residual water content of less than 1000 ppm or even 500 ppm.
- the condensation temperature is carefully adjusted according to the pressure prevailing in the system and so as to avoid solidification of the lactide. It will be between 70 and 125 ° C.
- the volatile compounds extracted via line 513 are in turn condensed 550 and transferred, via line 551, to the hydrolysis tank 2000.
- the crude liquid lactide is supplied via line 511 in a recrystallization unit in the molten state 600 or the purification takes place in one or more stages according to a static and / or dynamic process at low temperature, below 105 ° C. , so as to recover, via line 601, a pure lactide in liquid form.
- the latter is characterized by a lactide content of between 99.0 and 99.9% and preferably still between 99.5 and 99.9%, a meso-LD content of between 0 and 1% and preferably between 0 and 0 , 5%, a water content between 0 and 200 ppm and preferably between 0 and 50 ppm, as well as an acidity between 0 and 10 meq / kg and preferably between 0 and 1 meq / kg.
- the first, extracted via line 603, contains a sufficient residual L-LD content so that it can be mixed with the crude lactide obtained from the selective condensation step 511. A sufficient residual L-LD content is considered to be being between 60 and 99%.
- the second residue (drain) extracted via line 602 contains a residual L-LD content of between 80% and 35% and is sent in liquid form to the extractive crystallization unit 700.
- the drain is mixed with an aqueous phase supplied via line 702 with a water content which can range from 0 to 40%.
- the aqueous phase supplied can come from the condensates of the evaporation step via line 212 or at least in part from the subsequent step of drying the pre-purified lactide via line 904.
- the temperature of the mixture is then reduced so as to avoid excessive supersaturation, so as to control the geometry of the crystals formed and to favor a phase segregation between the lactide (solid phase) and the impurities (liquid phase).
- the suspension of crystals thus obtained is then transferred, via line 701, to a solid / liquid separation unit 800 in order to obtain on the one hand a liquid phase poor in lactide and charged with impurities which will be sent via line 802 to the hydrolysis tank 2000.
- a wet cake rich in lactide crystals is recovered, characterized by a free water content of between 0 and 10%, a total lactide content of between 60 and 99%, a content in lactic acid and lactic acid oligomers between 0 and 5%, and a meso-lactide content between 0 and 15%.
- the wet cake is then fed, via line 801, to a low temperature dryer 900 (product temperature below 45 ° C) to avoid melting of the mesolactide, which will reduce the residual water content and the '' bring to a value between 1000 and 50 ppm.
- a low temperature dryer 900 product temperature below 45 ° C
- the pre-purified lactide extracted from the dryer via line 901 and liquefied in a heater 910 from which it will be extracted via line 911 it will either be mixed, via line 913, with the product fed to the stage 1 of the recrystallization stage in the molten state, either supplied directly to one of the intermediate stages of the recrystallization stage in the molten state (not shown), or finally mixed, via line 912, with the Purified L-LD from the recrystallization step in the molten state 601 to then be polymerized.
- the mixture between the pre-purified lactide 912 and the purified L-LD 601 will be adapted so as to control the content of D-lactic unit (originating from the meso-lactide) present in the final polymer.
- the purified L-LD 601 or the mixture of purified L-LD 601 and pre-purified lactide 912 is mixed with an active principle and brought to the polymerization temperature which can be between 120 and 220 ° C. in a prepolymerization reactor 1000.
- the active principle or catalyst is stored in tank 1020 and fed via line 1021. Its concentration will be managed so as to maintain the monomer / catalyst ratio between 500 and 10,000, the exact content being a function of the type of polymer desired.
- the catalyst mentioned above can also correspond to the mixture of a catalyst with a co-catalyst such as for example, octoate / triphenylphosphine binomial.
- the product from the prepolymerization reactor can already consist of a prepolymer characterized by a molecular weight of between 10,000 and 50,000.
- the latter is supplied via line 1001 to a polymerization reactor 1100 which will preferably be of the twin-screw extruder type in order to continue and finalize the polymerization.
- the polymer resulting from this step 1101 is characterized by a molecular mass which can be between 40,000 and 350,000 and a conversion greater than 95% or even 98%.
- comonomers, copolymers or additives can be mixed with the lactide flow, but this approach is not shown in fig. 1.
- Another preferred approach of the present invention consists in sending the crude lactide 511 resulting from the selective condensation via the line 512 to the extractive crystallization unit 700.
- the crude lactide is mixed with an aqueous phase supplied via line 702 with a water content ranging from 0 to 40%.
- the temperature of the mixture is then lowered so as to avoid excessive supersaturation, so as to control the geometry of the crystals formed and to favor a phase segregation between the lactide (solid phase) and the impurities (liquid phase).
- the suspension of crystals thus obtained is then transferred, via line 701, to a solid-liquid separation unit 800 in order to obtain, on the one hand, a liquid phase poor in lactide and charged with impurities which will be sent via line 802 to the hydrolysis tank 2000.
- a wet cake rich in lactide crystals is recovered, characterized by a free water content of between 0 and 10%, a total lactide content of between 60 and 99%, a content of lactic acid and oligomers of lactic acid between 0 and 5%, and a meso-lactide content between 0 and 15%.
- the wet cake is then fed, via line 801, to a low temperature dryer (900) which will reduce the residual water content and bring it to a value between 1000 and 50 ppm.
- Residual L-LD sufficient to be between 60 and 99%.
- the second residue (drain) extracted via line 602 contains a residual L-LD content of between 80% and
- a stock of lactic acid oligomers was fed into a depolymerization unit at one month intervals in order to confirm or deny the consistency of the results and therefore, the possibility of recycling the D-lactic units directly in the process. of lactide synthesis.
- the oligomer was kept fluid in a closed enclosure, with stirring and at a temperature of 140 ° C.
- the oligomer was mixed for 2% of its weight with tin octoate and, fed (25-30 kg / h) in a thin layer evaporator maintained at 235 ° C and a surface equal to 2 m 2 .
- the vapor generated is condensed and the product obtained weighed in order to determine the productivity of the system but also analyzed in order to determine its selectivity.
- Table I Characterization of the oligomer and the efficiency of the depolymerization
- a stirred and heated reactor using 2 electrical resistors (1.2 k and 2.3 kW) was supplied with 20 liters of lactic acid sold by the company GALACTIC under the label "heat stable” and characterized by a concentration of 90% and an L-isomer content of 97.6%.
- the temperature of the heating elements and within the liquid is regulated so as to avoid any deviation greater than 20 ° C and the maximum temperature not exceeding 160 ° C.
- the unit is gradually placed under vacuum, the pressure varying between atmospheric pressure and 150 mbar.
- the reactor is surmounted by a column with a height of 0.9m and a section of 0.09m filled with Rashig rings (10 X 10 mm).
- a temperature sensor placed at the head of the column makes it possible to control the temperature of the vapors and if necessary to reduce the heating power in order to avoid too much entrainment.
- tin octoate To the oligomer obtained above and kept stirring at a temperature of 120 ° C is added 3% by weight of tin octoate.
- the mixture is fed at a flow rate of 3 kg / h in a thin layer evaporator of the thin-film type in stainless steel 316 with a surface of 0.2 m 2 , the walls of which are heated by an oil circulation whose temperature is maintained at 220-230 ° C.
- the vapors generated are condensed in a condenser with a surface area of 1 m 2 made of stainless steel 316, the temperature of the “refrigerant” fluid being maintained between 80 and 90 ° C.
- the entire unit is controlled under a pressure of between 5 and 10 mbar absolute.
- the crude lactide is collected at the outlet of the condenser at a rate of 2.45 kg / ha, an L-lactide content varying between 85 and 92% and a meso-lactide content varying between 3 and 7%.
- a sample of the crude lactide obtained above (800 g) containing 86.4% of L-LD, 4.8% of meso-LD, and a residual acidity of 310 meq / kg is introduced into a crystallizer consisting of a vertical stainless steel tube 1 m long and 30 mm in diameter.
- the double jacket of the tube is supplied with heat transfer fluid by a thermostatically controlled heating group for controlling the crystallization, sweating or recasting phases. This crude is melted at 105 ° C.
- the liquid phase is extracted by gravity.
- the crystals are still covered with a film of impurities which the sweating step must remove: the surface of the tube will be very gradually heated (from 60 to 98 ° C) so as to melt the surface of the crystals of lower purity , because their melting point is lower than that of the pure product.
- the crystallizer is brought (at 10 ° C / min) to the melting of the product (97-102 ° C) in order to liquefy the whole harvested by gravity (melt).
- a final product having to meet the specifications of a lactide for synthesis of PLA, will undergo several successive stages of purification by the same procedure.
- Table II shows the enrichment of the intermediate fractions as well as the mass yield (Yield) in L-
- the L-LD and meso-LD contents are determined by GC after silylation of the carboxylated compounds.
- the acidities are titrated by tetrabutylamine hydroxide potentiometry
- the product from the pre-purification in the aqueous phase can be recycled at any level of the purification sequence by crystallization in the molten state.
- a crude lactide sample containing 79.1% L-LD, 9.2% meso-LD, will undergo an aqueous prepurification treatment.
- a small amount (5g) of the dried product from this treatment was mixed with 5g of L-LD obtained by crystallization in the molten state (see Table IV, Stage 4: L- LD 99.95%; acidity 3 meq / kg ; water 47 ppm).
- This mixture was introduced into a test tube under nitrogen sweep. After solubilization of the mixture (100 ° C) a solution of tin octoate was added so as to respect a monomer / catalyst molar ratio of 4500. Once the solution is well homogenized, it is immersed in an oil bath, the temperature is thermostatically controlled at 180 ° C. After one hour of synthesis, the test tube is removed and broken so as to recover a very rigid and opaque polymer.
- Example b A quantity of 20 liters of ethyl lactate sold by the company GALACTIC under the label "Galaster EL 97" and characterized by a concentration of ethyl ester of 97% is supplied to the installation described in Example b.
- para-toluenesulfonic acid is added as catalyst at a concentration of 0.5% by weight.
- the temperature of the heating elements and within the liquid is regulated so as to avoid any deviation greater than 20 ° C and the maximum temperature not exceeding 175 ° C. To facilitate the rapid extraction of the volatile compound and to avoid an excessive entrainment of ester in the distillates, the procedure will be as in Example b.
- the crude lactide is collected at the outlet of the condenser at a flow rate of 1.78 kg / ha, an L-lactide content varying between 73 and 78% and a mesolactide content varying between 2 and 5%.
- a sample of the crude lactide obtained above (750 g) containing 75.3% L-LD, 2.3% meso-LD, and an acidity residual of 83 meq / kg is treated by following a procedure identical to that exposed in example b.
- Table VI shows the enrichment of the intermediate fractions as well as the mass yield in overall L-LD of the operation.
- the drain from the first stages were mixed so as to obtain a mixture containing 42.3% of L-LD and 5.2% of meso-LD. It will undergo a pre-purification, before being mixed with the product resulting from the depolymerization for purification by recrystallization in the molten state identical to Example b.
- Example b To the 1.050 kg of crude at 80 ° C. are added 25% by weight of cold water and the procedure described in Example b was repeated.
- the dried product resulting from this treatment after being mixed with the product resulting from the depolymerization, will undergo several stages of purification by recrystallization in the molten state, in accordance with example b.
- Table VIII shows an increase in the yield and efficiency of the purification in the molten state.
- the product from the pre-purification in the aqueous phase can be recycled at any level of the purification sequence by crystallization in the molten state.
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Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
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GB0503925A GB2407572B (en) | 2002-08-06 | 2003-08-04 | Process for the production of purified lactide and of polylactide from a solution of lactic acid or of one of its derivatives |
US10/523,061 US7488783B2 (en) | 2002-08-06 | 2003-08-04 | Method for the production of polyactide from a solution of lactic acid or one of the derivatives thereof |
AU2003262562A AU2003262562A1 (en) | 2002-08-06 | 2003-08-04 | Method for the production of polylactide from a solution of lactic acid or one of the derivatives thereof |
JP2004526917A JP4824308B2 (ja) | 2002-08-06 | 2003-08-04 | 乳酸又はその誘導体に於ける溶液からのポリラクチド生成方法 |
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BE2002/0469A BE1015060A3 (fr) | 2002-08-06 | 2002-08-06 | Procede de production de polylactide au depart d'une solution d'acide lactique ou d'un de ses derives. |
BE2002/0469 | 2002-08-06 |
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WO2004014889A1 true WO2004014889A1 (fr) | 2004-02-19 |
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PCT/EP2003/050360 WO2004014889A1 (fr) | 2002-08-06 | 2003-08-04 | Procede de production de polylactide au depart d'une solution d'acide lactique ou d'un de ses derives. |
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US (1) | US7488783B2 (fr) |
JP (1) | JP4824308B2 (fr) |
CN (1) | CN100345838C (fr) |
AU (1) | AU2003262562A1 (fr) |
BE (1) | BE1015060A3 (fr) |
FR (1) | FR2843390B1 (fr) |
GB (1) | GB2407572B (fr) |
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US7326550B2 (en) | 1997-09-12 | 2008-02-05 | Tate & Lyle Ingredients Americas, Inc. | Yeast strains for the production of lactic acid |
US7473540B2 (en) | 2005-09-22 | 2009-01-06 | Tate & Lyle Ingredients Americas, Inc. | Methods for selecting a yeast population for the production of an organic acid and producing an organic acid |
WO2012055997A1 (fr) | 2010-10-28 | 2012-05-03 | Total S.A. | Procédé pour la production de poly(acide lactique) utilisant monascus |
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AT506768B1 (de) | 2008-04-16 | 2013-10-15 | Jungbunzlauer Austria Ag | Verfahren zur reinigung zyklischer diester der l- bzw. d-milchsäure |
ES2554803T3 (es) | 2008-08-29 | 2015-12-23 | Uhde Inventa-Fischer Gmbh | Procedimiento de preparación de una mezcla de derivados de lactida |
CN101665566B (zh) * | 2008-09-01 | 2012-01-04 | 南京工业大学 | 一种利用双螺杆挤出机制备聚乳酸及其制品的方法 |
BE1018628A3 (fr) * | 2009-01-16 | 2011-05-03 | Futerro Sa | Acide polylactique isotactique et son procede de fabrication. |
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WO2015086613A1 (fr) * | 2013-12-10 | 2015-06-18 | Futerro S.A. | Procédé perfectionné de production de polylactide |
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WO2023025818A1 (fr) * | 2021-08-26 | 2023-03-02 | Futerro S.A. | Valorisation d'un flux d'acide d-lactique par séparation l/d dans le procédé de production d'acide l-polylactique |
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- 2002-08-06 BE BE2002/0469A patent/BE1015060A3/fr not_active IP Right Cessation
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2003
- 2003-08-04 US US10/523,061 patent/US7488783B2/en not_active Expired - Lifetime
- 2003-08-04 CN CNB038238721A patent/CN100345838C/zh not_active Expired - Lifetime
- 2003-08-04 GB GB0503925A patent/GB2407572B/en not_active Expired - Lifetime
- 2003-08-04 WO PCT/EP2003/050360 patent/WO2004014889A1/fr active Application Filing
- 2003-08-04 JP JP2004526917A patent/JP4824308B2/ja not_active Expired - Lifetime
- 2003-08-04 AU AU2003262562A patent/AU2003262562A1/en not_active Abandoned
- 2003-08-05 FR FR0309666A patent/FR2843390B1/fr not_active Expired - Lifetime
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WO1993015127A1 (fr) * | 1992-01-24 | 1993-08-05 | Cargill, Incorporated | Procede continu de fabrication de lactide et de polymeres de lactide |
US6326458B1 (en) * | 1992-01-24 | 2001-12-04 | Cargill, Inc. | Continuous process for the manufacture of lactide and lactide polymers |
US5521278A (en) * | 1994-08-18 | 1996-05-28 | Ecological Chemical Products | Integrated process for the manufacture of lactide |
EP1136480A1 (fr) * | 2000-03-23 | 2001-09-26 | Brussels Biotech | Procedé de purification d'esters cycliques |
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US7326550B2 (en) | 1997-09-12 | 2008-02-05 | Tate & Lyle Ingredients Americas, Inc. | Yeast strains for the production of lactic acid |
US7473540B2 (en) | 2005-09-22 | 2009-01-06 | Tate & Lyle Ingredients Americas, Inc. | Methods for selecting a yeast population for the production of an organic acid and producing an organic acid |
WO2012055997A1 (fr) | 2010-10-28 | 2012-05-03 | Total S.A. | Procédé pour la production de poly(acide lactique) utilisant monascus |
Also Published As
Publication number | Publication date |
---|---|
US7488783B2 (en) | 2009-02-10 |
CN100345838C (zh) | 2007-10-31 |
JP2006501213A (ja) | 2006-01-12 |
JP4824308B2 (ja) | 2011-11-30 |
AU2003262562A1 (en) | 2004-02-25 |
GB0503925D0 (en) | 2005-04-06 |
FR2843390B1 (fr) | 2005-03-11 |
BE1015060A3 (fr) | 2004-09-07 |
US20060014975A1 (en) | 2006-01-19 |
FR2843390A1 (fr) | 2004-02-13 |
GB2407572A (en) | 2005-05-04 |
GB2407572B (en) | 2006-09-06 |
CN1688569A (zh) | 2005-10-26 |
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