scholarly journals Cyclic Oligolactic Acid in Direct Polycondensation PLLA and Its Extraction with Organic Solvent

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Keiichiro Nomura ◽  
Yuta Nakatsuchi ◽  
Ryugo Shinmura ◽  
Sommai Pivsa-Art ◽  
Weraporn Pivsa-Art ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Lactic Acid ◽  
Selective Extraction ◽  
Condensation Polymerization ◽  
Direct Polycondensation ◽  
H Nmr ◽  
Repeat Units ◽  
Molecular Inclusion ◽  
Cyclic Compounds ◽  
Direct Condensation

The contents of poly(L-lactic acid) (PLLA) prepared by direct condensation polymerization without using a catalyst were studied. 1H NMR and mass spectrometry analyses suggested that PLLA contained cyclic oligo(L-lactic acid) (c-OLLA) with 3–20 repeat units. Notably, only c-OLLA was extracted and isolated using hexane or cyclohexane at 4°C; thus the hydrophobicity, topology, and temperature dependence of the solubility of the obtained PLLA enabled the selective extraction of c-OLLA. The effect of cyclic compounds on direct polycondensation and the potential for c-OLLA to form molecular inclusion complexes were also discussed.

Direct condensation polymerization of lactic acid

1999 ◽  
Vol 144 (1) ◽  
pp. 277-287 ◽  
Author(s):  
Soo Hyun Kim ◽  
Young Ha Kim
Keyword(s):  
Lactic Acid ◽  
Condensation Polymerization ◽  
Direct Condensation

Basic Properties of Polylactic Acid Produced by the Direct Condensation Polymerization of Lactic Acid

1995 ◽  
Vol 68 (8) ◽  
pp. 2125-2131 ◽  
Author(s):  
Masanobu Ajioka ◽  
Katashi Enomoto ◽  
Kazuhiko Suzuki ◽  
Akihiro Yamaguchi
Keyword(s):  
Lactic Acid ◽  
Polylactic Acid ◽  
Condensation Polymerization ◽  
Basic Properties ◽  
Direct Condensation

Direct Condensation Polymerization of L-Lactic Acid Catalyzed by Distannoxane

1996 ◽  
Vol 25 (3) ◽  
pp. 225-226 ◽  
Author(s):  
Junzo Otera ◽  
Kazuko Kawada ◽  
Toru Yano
Keyword(s):  
Lactic Acid ◽  
Condensation Polymerization ◽  
Acid Catalyzed ◽  
Direct Condensation

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

2021 ◽  
pp. 174751982110210
Author(s):  
Xiaolong Xu ◽  
Lijuan Liu
Keyword(s):  
Lactic Acid ◽  
Acid Solution ◽  
Concentration Distribution ◽  
Raw Material ◽  
High Concentration ◽  
Composition Distribution ◽  
Lactic Acid Solution ◽  
H Nmr ◽  
Back Titration ◽  
Condensed Water

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.

scholarly journals Measurement of δ18O and δ2H of water and ethanol in wine by Off-Axis Integrated Cavity Output Spectroscopy and Isotope Ratio Mass Spectrometry

2021 ◽  
Author(s):  
Xing Wang ◽  
Henk G. Jansen ◽  
Haico Duin ◽  
Harro A. J. Meijer
Keyword(s):  
Mass Spectrometry ◽  
Isotope Ratio ◽  
Isotope Analysis ◽  
Isotope Ratio Mass Spectrometry ◽  
Growth Conditions ◽  
The Other ◽  
H Nmr ◽  
Cavity Output ◽  
Pre Treatment ◽  
Output Laser

AbstractThere are two officially approved methods for stable isotope analysis for wine authentication. One describes δ18O measurements of the wine water using Isotope Ratio Mass Spectrometry (IRMS), and the other one uses Deuterium-Nuclear Magnetic Resonance (2H-NMR) to measure the deuterium of the wine ethanol. Recently, off-axis integrated cavity output (laser) spectroscopy (OA-ICOS) has become an easier alternative to quantify wine water isotopes, thanks to the spectral contaminant identifier (SCI). We utilized an OA-ICOS analyser with SCI to measure the δ18O and δ2H of water in 27 wine samples without any pre-treatment. The OA-ICOS results reveal a wealth of information about the growth conditions of the wines, which shows the advantages to extend the official δ18O wine water method by δ2H that is obtained easily from OA-ICOS. We also performed high-temperature pyrolysis and chromium reduction combined with IRMS measurements to illustrate the “whole wine” isotope ratios. The δ18O results of OA-ICOS and IRMS show non-significant differences, but the δ2H results of both methods differ much more. As the δ2H difference between these two methods is mainly caused by ethanol, we investigated the possibility to deduce deuterium of wine ethanol from this difference. The results present large uncertainties and deviate from the obtained 2H-NMR results. The deviation is caused by the other constituents in the wine, and the uncertainty is due to the limited precision of the SCI-based correction, which need to improve to obtain the 2H values of ethanol as alternative for the 2H-NMR method.

scholarly journals Synthesis and Characterization of Polyphosphazenes Modified with Hydroxyethyl Methacrylate and Lactic Acid

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Evelyn Carolina Martínez Ceballos ◽  
Ricardo Vera Graziano ◽  
Gonzalo Martínez Barrera ◽  
Oscar Olea Mejía
Keyword(s):  
Lactic Acid ◽  
Ring Opening ◽  
Room Temperature ◽  
Block Structure ◽  
Ring Opening Polymerization ◽  
Synthesis And Characterization ◽  
Poly Lactic Acid ◽  
Hydroxyethyl Methacrylate ◽  
H Nmr

Poly(dichlorophosphazene) was prepared by melt ring-opening polymerization of the hexachlorocyclotriphosphazene. Poly[bis(2-hydroxyethyl-methacrylate)-phosphazene] and poly[(2-hydroxyethyl-methacrylate)-graft-poly(lactic-acid)-phosphazene] were obtained by nucleophilic condensation reactions at different concentrations of the substituents. The properties of the synthesized copolymers were assessed by FTIR,1H-NMR and31P-NMR, thermal analysis (DSC-TGA), and electron microscopy (SEM). The copolymers have a block structure and show twoTg's below room temperature. They are stable up to a temperature of 100°C. The type of the substituents attached to the PZ backbone determines the morphology of the polymers.

scholarly journals Direct condensation polymerization of N-alkylated p-aminobenzoic acid and packing of rigid-rod main chains with flexible side chains

2010 ◽  
Vol 42 (1) ◽  
pp. 72-80 ◽  
Author(s):  
Yuji Shibasaki ◽  
Yoko Abe ◽  
Natsuki Sato ◽  
Atsuhiro Fujimori ◽  
Yoshiyuki Oishi
Keyword(s):  
Side Chains ◽  
Condensation Polymerization ◽  
Aminobenzoic Acid ◽  
Rigid Rod ◽  
Direct Condensation
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