57321-93-4

Upstream product

• 136532-17-7 2-(2-hydroxyacetoxy)propionic acid 
• 1052113-53-7 benzyl 2-(2-hydroxyacetoxy)propionate 
• 79-14-1 glycolic Acid 

Relevant academic research and scientific papers

Synthesis, Microstructure, and Properties of High-Molar-Mass Polyglycolide Copolymers with Isolated Methyl Defects

An efficient, fast, and reliable method for the synthesis of high-molar-mass polyglycolide (PGA) in bulk using bismuth (III) subsalicylate through ring-opening transesterification polymerization is described. The difference between the crystallization (Tc ≈ 180 °C)/degradation (Td ≈ 245 °C) temperatures and the melting temperature (Tm ≈ 222 °C) significantly affects the ability to melt-process PGA homopolymer. To expand these windows, the effect of copolymer microstructure differences through incorporation of methyl groups in pairs using lactide or isolated using methyl glycolide (≤10% methyl) as comonomers on the thermal, mechanical, and barrier properties were studied. Structures of copolymers were characterized by nuclear magnetic resonance (1H and 13C NMR) spectroscopies. Films of copolymers were obtained, and the microstructural and physical properties were analyzed. PGA homopolymers exhibited an approximately 30 °C difference between Tm and Tc, which increased to 68 °C by incorporating up to 10% methyl groups in the chain while maintaining overall thermal stability. Oxygen and water vapor permeation values of solvent-cast nonoriented films of PGA homopolymers were found to be 4.6 cc·mil·m-2·d-1·atm-1 and 2.6 g·mil·m-2·d-1·atm-1, respectively. Different methyl distributions in the copolymer sequence, provided through either lactide or methyl glycolide, affected the resulting gas barrier properties. At 10% methyl insertion, using lactide as a comonomer significantly increased both O2 (32 cc·mil·m-2·d-1·atm-1) and water vapor (12 g·mil·m-2·d-1·atm-1) permeation. However, when methyl glycolide was utilized for methyl insertion at 10% Me content, excellent barrier properties for both O2 (2.9 cc·mil·m-2·d-1·atm-1) and water vapor (1.0 g·mil·m-2·d-1·atm-1) were achieved.

METHOD FOR PRODUCING CYCLIC ESTER

In a method for producing a cyclic ester according to an embodiment of the present invention, a mixture (I) containing an aliphatic polyester, a specific polyalkylene glycol diether, and a sulfonic acid compound as a thermal stabilizer is prepared and heated in predetermined conditions to obtain a mixture (II) in a state of solution. Furthermore, heating of the mixture (II) is continued to distill, together with the polyalkylene glycol diether, a cyclic ester formed by the depolymerization reaction, and thus a distillate (III) is obtained. The cyclic ester is recovered from the distillate (III). At this time, a specific solubilizing agent is added to at least one of the mixture (I) or (II). In this production method, the sulfonic acid compound as the thermal stabilizer is contained in the mixtures (I) and (II) and the distillate (III).

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.

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 the corresponding 3-alkyl-5-acetyl-6-methyl-2,3-dihydro-1,4-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. Successive chlorination and dechlorination of 6-hydroxymethy 1-1,4-dioxan-2-ones yielded 6-methylene-1,4-dioxan-2-ones.

A versatile route to functionalized dilactones as monomers for the synthesis of poly(α-hydroxy) acids

A synthetic pathway to functionalized six-membered dilactones structurally analogous to lactide is described. Through the use of orthogonal protecting groups, the synthesis of functionalized dilactones was performed in a straightforward way by cyanuric chloride-mediated cyclization of the corresponding linear α-hydroxy acid dimers. The synthesis of three different dilactones - methylglycolide, benzyloxymethylglycolide, and 2-benzyloxymethyl-5-methylglycolide - by the same procedure demonstrated the versatility of this route. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.

Process for the preparation of 1,4-dioxane-2,5-diones

This invention relates to a process for preparing 1,4-dioxane-2,5-diones comprising reacting an α-hydroxy acid oligomer or an ester of an α-hydroxy acid oligomer over a fixed bed catalyst system.