II. Ueber Derivate der Milchsäure

Bischoff, C. A.; Walden, P.

doi:10.1002/jlac.18942790107

Cited by 20 publications

(9 citation statements)

References 2 publications

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“…X-Ray powder diffractometry was carried out on a Siemens D5000 diffractometer equipped with a secondary monochromator and Braun 50 m position-sensitive detector (Cu-Ka radiation, h = 154.178 pm, 25 kV, 20 mA). Peak intensities for determination of extent of the reaction were calculated as integrals using pseudo-Voigt functions.26 X-Ray absorption fine structure spectra (EXAFS) were measured at the Hamburger Synchrotronstrahlungslabor (HASYLAB) at Deutsches Elektronen-Synchrotron (DESY), Hamburg, at beamline E4 (EXAFS 11). This is equipped with a nickel mirror and an Si( 1 1 1) double-crystal monochromator, yielding approximately 10'' photons s-l mm-2 at the sample.…”

Section: Experiments A1mentioning

confidence: 99%

Study of a solid-state polymerisation reaction: thermal elimination of NaCl from sodium chloroacetate

Epple¹,

Tröger²

1996

J. Chem. Soc., Dalton Trans.

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The thermal elimination of sodium chloride from sodium chloroacetate can be accomplished by heating the compound to 150-200 "C. The remaining polyester ['polyglycolide', poly( 1 -oxy-I -oxoethylene)] is obtained in high yield. The reaction was quantitatively studied by thermal analysis (DSC, TG-DTA-mass spectrometry), NMR spectroscopy in solution and in the solid state, X-ray powder diffractometry, electron microscopy and X-ray absorption fine structure spectroscopy (EXAFS). Proton NMR spectroscopy, X-ray diffractometry and chlorine K-edge EXAFS are all well suited to determine the extent of reaction with high accuracy. The reaction proceeds in the solid state in one step without intermediates. Sodium chloride crystals (d = 1-2 pm) are deposited in a polyglycolide matrix while the external crystal morphology is preserved. Combustion of the polyglycolide leaves a sodium chloride framework. Washing out the sodium chloride with water leaves a porous polyglycolide matrix with cubic holes ('inverse NaCl crystals').Solid-state photopolymerisation reactions of organic compounds are known for unsaturated hydrocarbons, i. e. alkenes and alkynes. For example, it is possible to synthesise polyacetylenes by these methods. The study of this field of organic solid-state chemistry has been pioneered by Schmidt and continued, e.g. by the groups of C ~h e n , ~-~ Enkelman~~,'.~ Hasegawa,' Lahav,* Thomas' and Wegner." In these reactions the necessary energy for the polymerisation step is provided by radiation, i. e. photopolymerisation occurs. In general, it is a photoaddition involving unsaturated organic compounds. Such topochemical reactions are now well understood from the viewpoint of crystallography.Much less is known about thermally induced polymerisation reactions in the solid state. We now report a detailed study on the thermal elimination of sodium chloride from sodium chloroacetate which leads to a polyester [equation (I)]. This ClCH,CO,-Na+ -NaCl + 4 (-CH,CO,-), (1) strongly exothermic reaction occurs upon simply heating sodium chloroacetate above 140 "C. The organic part of the molecule polymerises to the simplest polyester, called 'polpglycolide' [poly( I -oxy-1 -oxoethylene)]. The reaction was first discovered in 1894 by Bischoff and Walden. l 1 It was studied to some extent in the first half of this century,l2*l3 but no mechanistic studies have been performed to date. Here, the course of the reaction was followed by differential scanning calorimetry (DSC), combined thermogravimetry-differential thermal analysismass spectroscopy (TG-DTA-MS), NMR spectroscopy in solution and in the solid state, X-ray diffractometry (XRD), X-ray absorption spectroscopy (extended X-ray absorption fine structure, EXAFS) at the chlorine K-edge and scanning electron microscopy (SEM). Results and DiscussionSodium chloroacetate is metastable with respect to the thermal elimination. Unfortunately, the enthalpy of formation is not t Non-SI unit employed: eV z 1.60 x J.

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Section: Experiments A1mentioning

confidence: 99%

Study of a solid-state polymerisation reaction: thermal elimination of NaCl from sodium chloroacetate

Epple¹,

Tröger²

1996

J. Chem. Soc., Dalton Trans.

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“…J values are given in Hz. 13 C NMR spectra were recorded on a 125 MHz FT-NMR spectrometer (JEOL JNM-GSX500 or LA500). Wide angle X-ray diffraction patterns were obtained for specimens on Rigaku XG X-ray diffraction apparatus with Cu-K α radiation (35 kV, 20 mA) by the powder method.…”

Section: Methodsmentioning

confidence: 99%

Thermal reactions of alkali 4-(bromomethyl)benzoate–bromoacetate binary systems in the bulk

Inoki¹,

Akutsu²,

Fang³

et al. 1997

J. Chem. Soc., Perkin Trans. 2

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Thermal reactions of alkali 4-(bromomethyl)benzoate-bromoacetate (4-BMBA-BA) binary systems in the bulk have been investigated. Those of equimolar sodium and potassium 4-BMBA-BA result in copolycondensation in the solid state to give a copolyester. However, reaction of the equimolar lithium salts at 210 ЊC for 1 h, followed by esterification, afford methyl 4-(bromomethyl)benzoyloxyacetate as a cross-condensed dimer in 30% yield. The yield increases in the initial hour, but then gradually decreases due to the formation of oligomers. The X-ray diffraction pattern of the Li salts (powder method) indicates a new crystal phase, which is different from the individual patterns of lithium bromoacetate and lithium 4-(bromomethyl)benzoate. The formation of the new crystal phase contributes to a reduced melting point, and the Li salts react in the liquid phase without pyrolysis, causing cross-condensed dimerization.

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“…Lactide was first identified in 1863 by Henry, who determined its structural formula and noted that the molecule includes two ester bonds [119]. Racemic DL-lactide was obtained 20 years later by Bischoff and Walden by heating 1) the sodium salt of α-bromopropionic acid in a vacuum [120,121] or 2) αbromopropionic anhydride with K2CO3 [122]. A thorough study on all the optical isomers of lactide was later presented by Jungfleisch and Godchot [123,124].…”

Section: "Pioneer" Syntheses Of Glycolide and Lactidementioning

confidence: 99%

“…During polycondensation at heating in a vacuum, they can successfully isolated crystals that melted at 82-83°C and proved a glycolide structure. Later, Bischoff and Walden obtained glycolide by heating the sodium bromoacetic acid salt in a vacuum [ [121]]. They also discovered that heating PGA in a vacuum is accompanied by its depolymerization that leads to the formation of glycolide.…”

Section: "Pioneer" Syntheses Of Glycolide and Lactidementioning

confidence: 99%

“…One of the pioneering methods for the production of glycolide and lactide is their synthesis from the salts of halogen derivatives of glycolic and lactic acids. Lactide is obtained either by heating a salt of α-bromopropionic acid [120,121] or potassium carbonate with α-bromopropionic anhydride [122]. Glycolide is synthesized from the sodium salt of bromoacetic acid in a vacuum [120].…”

Section: Cyclic Esters Synthesis From Halogen Derivatives Of Hydroxycarboxylic Acidsmentioning

confidence: 99%

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Syntheses and chemical transformations of glycolide and lactide as monomers for biodegradable polymers

Ботвин

Karaseva

Salikova

et al. 2021

Polymer Degradation and Stability

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Glycolide and lactide function as the commonly used diester monomers for the preparation of high-molecular weight, degradation-prone (co-)polyesters. Both glycolide and lactide-based polymers are widely used in medicine, pharmaceuticals, the food industry, and additive technologies. This review on the diesters, spanning research from 1833-1854 to the present, encompassing their structural peculiarities, physico-chemical properties, and the range of different methods for obtaining themincluding reaction mechanismsfrom lactic and glycolic acids, their esters, and halogen derivatives. The review also discusses the chemical transformations of lactide and glycolide (apart from ring-opening polymerization) into valuable organic and high-molecular compounds, such as acrylic acid, nitrogen-containing heterocycles, and functional polymers with novel properties.

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II. Ueber Derivate der Milchsäure

Cited by 20 publications

References 2 publications

Study of a solid-state polymerisation reaction: thermal elimination of NaCl from sodium chloroacetate

Study of a solid-state polymerisation reaction: thermal elimination of NaCl from sodium chloroacetate

Thermal reactions of alkali 4-(bromomethyl)benzoate–bromoacetate binary systems in the bulk

Syntheses and chemical transformations of glycolide and lactide as monomers for biodegradable polymers

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