26680-10-4

Basic information

• Product Name: 3,6-Dimethyl-1,4-dioxane-2,5-dione homopolymer
• Synonyms: 3,6-Dimethyl-1,4-dioxane-2,5-dione homopolymer;Lactide polymer;PDLLA;RESOMER(R) R 203 S;RESOMER(R) R 202 S;RESOMER(R) R 202 H;RESOMER(R) R 203 H;RESOMER? R 203 H
• CAS NO: 26680-10-4
• Molecular Formula: C6H8O4
• Molecular Weight: 144.12532
• Product Categories: Biodegradable Polymers;Lactide and Glycolide Polymers;Materials Science;Polymer Science;Polymers
• Mol File: 26680-10-4.mol
• Article Data: 63

Chemical Properties

• Melting Point: 215 °C
• Flash Point: 113°C
• Appearance: /
• Density: 1.23 g/cm3
• Storage Temp.: 2-8°C
• Solubility: Soluble in dichloromethane, tetrahydrofuran, ethyl acetate, chloroform, hexafluoroisopropanol, and acetone. Insoluble in water.
• CAS DataBase Reference: 3,6-Dimethyl-1,4-dioxane-2,5-dione homopolymer(CAS DataBase Reference)
• NIST Chemistry Reference: 3,6-Dimethyl-1,4-dioxane-2,5-dione homopolymer(26680-10-4)
• EPA Substance Registry System: 3,6-Dimethyl-1,4-dioxane-2,5-dione homopolymer(26680-10-4)

Safety Data

• WGK Germany: nwg
• Hazardous Substances Data: 26680-10-4(Hazardous Substances Data)

Usage

Chemical Properties

Poly(DL-lactic acid) is a glassy material, occurring as white to golden-yellow pellets or granules.

Uses

Different sources of media describe the Uses of 26680-10-4 differently. You can refer to the following data:
1. Controlled release
2. May be used to make drug delivery materials for controlled release.

Production Methods

Lactic acid is a chiral molecule and has two optically active forms: Llactic acid and D-lactic acid. Poly(DL-lactic acid) is produced from the racemic mixture of lactic acid. Lactic acid is produced either from ethylene (petrochemical pathway) or by bacterial fermentation of D-glucose derived from food stocks. The former pathway involves an oxidation step followed by treatment with hydrogen cyanide and produces only racemic DL-lactic acid. In contrast, lactic acid produced by fermentation occurs mainly as L-lactic acid. Lowmolecular- weight poly-DL-(lactic acid) (500–10 000 Da) is produced directly from lactic acid by condensation. Higher-molecular-weight product is produced by one of two major pathways. The first involves a depolymerization of low-molecular-weight polymer into the cyclic dimer form (lactide) followed by ring-opening polymerization. Alternatively, it can be produced by a direct condensation using azeotropic distillation.

General Description

Resomer? R 207 S, Poly(D,L-lactide) (PDLLA), a biodegradable and biocompatible polymer, can be used for a variety of biological applications. It shows properties like long degradation time, mechanical stiffness and hydrophobicity.

Pharmaceutical Applications

Poly(DL-lactic acid) is used in drug delivery systems in implants, injections, and oral solid dispersions. It is also used as a coating agent.

Safety

Poly(DL-lactic acid) degrades to produce lactic acid, which is considered a well-tolerated nontoxic material. Several in vitro and in vivo studies demonstrated that poly(lactic acid) in general (including poly(DL-lactic acid)) is well tolerated and does not induce a significant immune response.However, some studies have illustrated signs of a mild immune response.The FDA has also reported some rare cases of inflammatory responses in patients treated with cosmetic poly(DL-lactic acid) injections.

storage

Poly(DL-lactic acid) is stable under dry conditions. However, it typically biodegrades over a period of 10–15 months according to the molecular weight. Increasing moisture and temperature enhances biodegradation; the onset of degradation in water at 25°C is 6 months.In contrast to many other biodegradable polymers, poly(DL-lactic acid) degrades through a two-step mechanism. The primary degradation step involves the hydrolysis of the ester bonds independently of microbial activity to produce a low-molecular-weight polymer. When the molecular weight drops below 10 000, microorganisms digest the polymer into carbon dioxide and water. Poly(DL-lactic acid) is more stable than poly(L-lactic acid) or poly(D-lactic acid) alone.Poly(DL-lactic acid) should be stored in a dry inert environment at a temperature of －15°C to －20°C.

Incompatibilities

Incompatible with strong acids or alkaline materials.

Regulatory Status

Included in the FDA Inactive Ingredients Database (IM, powder, for injection, suspension, and lyophilization). Poly(DL-lactic acid) is considered as ‘not hazardous’ according to the European Directive 67/548/EEC. Included in parenteral preparations (prolongedrelease powder for suspension for subcutaneous or intramuscular injection) licensed in the UK.

Upstream product

• 4511-42-6 L,L-dilactide 
• 123-54-6 acetylacetone 
• 27871-49-4 (S)-Methyl lactate 
• 10326-41-7 D-Lactic acid 
• 95-96-5 D,L-lactide 
• 849585-22-4 LACTIC ACID 
• 79-33-4 L-Lactic acid 
• 97-64-3 ethyl 2-hydroxypropionate 
• 13076-19-2 (3R,6S)-3,6-dimethyl-1,4-dioxane-2,5-dione 
• 13076-17-0 D-lactide 
• 26680-10-4 3,6-dimethyl-1,4-dioxane-2,5-dione 
• 1071822-17-7 (6S)-3-methylene-6-methyl-1,4-dioxane-2,5-dione 
• 547-64-8 methyl lactate 
• 338-69-2 D-Alanine 

Downstream Products

• 958298-96-9 (N,N'-bis(2,6-diisopropylphenyl)(tert-butyl)amidinato)tin(II)(OCH(Me)C(O)OCH(Me)C(O)OCHMe₂) 
• 26680-10-4 3,6-dimethyl-1,4-dioxane-2,5-dione 
• 7512-80-3 O-acetyl-lactyllactic acid ethyl ester 
• 13076-19-2 (3R,6S)-3,6-dimethyl-1,4-dioxane-2,5-dione 

Relevant articles and documents

Synthesis and characterization of a brush-like copolymer of polylactide grafted onto chitosan

A brush-like poly(DL)-lactide grafted onto chitosan as the backbone was investigated. The graft copolymerization was carried out with triethylaluminum as catalyst in toluene at 70°C. It was found that a greater lactide content in the feeding ratio results in a higher grafting percentage. FTIR spectrometry, 1H NMR, DSC scanning, and wide-angle X-ray scattering, respectively, are used to characterize these branch copolymers. A copolymer has a definite melting point when the molar feeding ratio of lactide to chitosan is more than 10:1, and the ΔH of the copolymers increases with the feed ratio of lactide to chitosan in feeding.

Chemical Recycling of End-of-Life Poly(lactide) via Zinc-Catalyzed Depolymerization and Polymerization

The chemical recycling of poly(lactide) was investigated based on depolymerization and polymerization processes. Using methanol as depolymerization reagent and zinc salts as catalyst, poly(lactide) was depolymerized to methyl lactate applying microwave heating. An excellent performance was observed for zinc(II) acetate with turnover frequencies of up to 45000 h?1. In a second step the monomer methyl lactate was converted to (pre)poly(lactide) in the presence of catalytic amounts of zinc salts. Here zinc(II) triflate revealed excellent performance for the polymerization process (yield: 91 %, Mn ～8970 g/mol). Moreover, the (pre)poly(lactide) was depolymerized to lactide, the industrial relevant molecule for accessing high molecular weight poly(lactide), using zinc(II) acetate as catalyst.

A study on highly concentrated lactic acid and the synthesis of lactide from its solution

Lactic acid is an important platform compound used as raw material for the production of lactide and polylactic acid. However, its concentration and composition distribution are not as simple as those of common compounds. In this work, the mass concentration distribution of highly concentrated lactic acid is determined by back titration. The components of highly concentrated lactic acid, crude lactide, and polymer after the reaction are analyzed by HPLC. Different concentrations of lactic acid solution were prepared for the synthesis of lactide and its content in the product was determined by 1H NMR analysis. We found that lactide is more easily produced from high-concentration lactic acid solution with which the condensed water is easier to release. Hence, the removal of condensed water is crucial to the formation of lactide, although it is not directly formed by esterification of two molecules of lactic acid.

Effect of block lengths on the association behavior of poly(l-lactic acid)/poly(ethylene glycol) (PLA-PEG-PLA) micelles in aqueous solution

A series of poly(l-lactic acid)/poly(ethylene glycol) triblock copolymers with a PLA-PEG-PLA architecture were synthesized by a ring-opening polymerization (ROP) process. The copolymers were characterized by 1H NMR and GPC. The total number average molecular weights were in the range of 4,700-50,000, whereas the degrees of polymerization of the PLA and PEG blocks varied from 15 to 359 and from 68 to 136, respectively. The self-association of these copolymers in aqueous environment was studied by emission fluorescence spectroscopy of anilinonaphthalene probe and the critical association concentration (CAC) of the copolymers was measured. It was found that the micellization process of these copolymers was mainly determined by the length of the hydrophobic LA block, while the length of the hydrophilic PEG block had little effect. Furthermore, the low CAC values of the copolymers suggest that the copolymers form stable supramolecular structures in aqueous solutions.

Synthesis of lactide from lactic acid and its esters in the presence of rare-earth compounds

A procedure is described for the synthesis of lactide by dehydration of L-lactic acid and subsequent depolymerization of its oligomer mixture in the presence of yttrium(III) and praseodymium(III) oxides, as well as of cerium(III) chloride heptahydrate. The catalytic activity of yttrium and praseodymium sesquioxides was determined at different temperatures at the oligomerization and deoligomerization stages. Ethyl lactate was prepared in the presence of Purolite C100 MB cation exchange resin and subjected to oligomerization followed by thermal decomposition of oligoester and oligolactic acid mixture in the presence of yttrium(III) and praseodymium(III) oxides and aqueous cerium(III) chloride.

Synthesis of New Substituted 2,3-Dihydro-1,4-dioxin-2-ones and 1,4-Dioxan-2-ones

3-Alkyl-6-methyl-2,3-dihydro-1,4-dioxin-2-ones reacted with acetyl chloride in the presence of zinc(II) chloride to give 5-acetyl-3-alkyl-6-methyl- 2,3-dihydro-l,4-dioxin-2-ones. Oxidation of the latter with hydrogen peroxide in formic acid, followed by treatment with magnesium bromide, afforded 3-alkyl-6-methyl-1,4-dioxane-2,5-diones. Chlorination of 6-hydroxymethyl-1,4- dioxan-2-ones with thionyl chloride and subsequent dehydrochlorination led to formation of 6-methylene-1,4-dioxan-2-ones.

Melt Chain Dimensions of Polylactide

Melt chain dimensions of two polylactide samples were measured using small-angle neutron scattering, Three polylactides were synthesized: a deuterated polylactide containing 26% R-stereocenters (d-PLA-26), a hydrogenous polylactide with an R-content similar to the deuterated polylactide (PLA-28), and a hydrogenous polylactide that contained no R-stereocenters (PLA-0). The hydrogenous polylactides were each solution blended with the d-PLA-26 at a volume fraction of 0.2 for the deuterated polymer, and the melt chain dimensions of these polymers were determined. Small-angle neutron scattering experiments were performed at 30°C for the d-PLA-26/PLA-28 blend and at 200°C for both the d-PLA-26/PLA-28 and d-PLA-26/PLA-0 blends. Using three analysis methods, the average values for the statistical segment lengths, based on a C6 repeat unit, were found to be 10.0 ± 0.2 A for the PLA-28 at 30°C, 8.9 ± 0.2 A for the PLA-28 at 200°C, and 9.9 ± 0.4 A for the PLA-0 at 200°C.

Method for catalytically synthesizing lactide

The invention discloses a method for catalytically synthesizing lactide. According to the method, a mixture of stannous lactate and a urea substance is used as a composite catalyst, L-lactic acid (orD-lactic acid) with the lactic acid content of 90% is used as a raw material, and a reduced pressure distillation technology is adopted to synthesize the L-lactide (or D-lactide). Compared with independent use of onecatalyst, by adopting the composite catalyst, the yield can be effectively increased, under the same experimental conditions, the crude yields of lactide synthesized by independently using stannous lactate or urea catalysts are 69%-72% and 23%-30% respectively, and the yield can be increased to 90% or above by using the composite catalyst of the two. Compared with a traditional tincatalyst or zinc catalyst and other composite catalytic components, the composite catalytic reaction system is low in reaction temperature (150-180 DEG C), short in reaction time (0.5-2 h), high in lactide yield (90% or above), capable of saving more energy and increasing the yield and beneficial to industrial production.

METHOD FOR SYNTHESIZING LACTIDE BY MEANS OF CATALYSIS OF LACTID ACID

The present invention relates to a method for the catalytic synthesis of lactide from lactic acid. The method relates to the synthesis of lactide from lactic acid under the catalysis of a zinc oxide nanoparticle aqueous dispersion as a catalyst. The present invention has four technical characteristics: I. the zinc oxide nanoparticle aqueous dispersion catalyst has a sufficient surface area, and the size of nanoparticles is merely 30-40 nm, providing a sufficient contact area between the substrate (lactic acid) and the catalyst; II. the new catalyst has a milder catalytic effect on polymerization, allowing the molecular weight distribution of a prepolymer within a range of 400-1500 g/mol, which is advantageous for depolymerization to proceed; III. the new catalyst is stable, thus avoiding oxidation or carbonization in a high temperature reaction; and IV. the new catalyst has a low toxicity and a small threat to human health.