928-04-1Relevant articles and documents
Environment-friendly preparation method of propiolic acid derivatives
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Paragraph 0022; 0024, (2020/02/14)
The invention discloses an environment-friendly preparation method of propiolic acid derivatives. The preparation method comprises the following steps: (1) with 2,3-dibromosuccinic acid as a raw material, generating a butynedioic acid salt under alkaline conditions; (2) under an acidic condition, carrying out high-temperature decarboxylation to obtain propiolic acid; and (3) adding corresponding methanol or ethanol into propiolic acid in an extraction solvent, and preparing high-yield propiolate under acidic catalytic conditions under the condition that trimethyl orthoformate or triethyl orthoformate participates in dehydration. In the invention, the propiolic acid preparation method is friendly to environment and high in safety coefficient; and the method provided by the invention can beused for preparing methyl propiolate and ethyl propiolate, and has the advantages of small alcohol consumption, thorough reaction, high yield and easiness in separation.
Eu(O2C-C≡C-CO2): An EuII Containing Anhydrous Coordination Polymer with High Stability and Negative Thermal Expansion
Gramm, Verena K.,Smets, Daniel,Grzesiak, Ireneus,Block, Theresa,P?ttgen, Rainer,Suta, Markus,Wickleder, Claudia,Lorenz, Thomas,Ruschewitz, Uwe
, p. 2726 - 2734 (2020/02/20)
Anhydrous EuII–acetylenedicarboxylate (EuADC; ADC2? = ?O2C-C≡C-CO2 ?) was synthesized by reaction of EuBr2 with K2ADC or H2ADC in degassed water under oxygen-free conditions. EuADC crystallizes in the SrADC type structure (I41/amd, Z=4) forming a 3D coordination polymer with a diamond-like arrangement of Eu2+ nodes (msw topology including the connecting ADC2? linkers). Deep orange coloured EuADC is stable in air and starts decomposing upon heating in an argon atmosphere only at 440 °C. Measurements of the magnetic susceptibilities (μeff=7.76 μB) and 151Eu M?ssbauer spectra (δ=?13.25 mm s?1 at 78 K) confirm the existence of Eu2+ cations. Diffuse reflectance spectra indicate a direct optical band gap of Eg=2.64 eV (470 nm), which is in accordance with the orange colour of the material. Surprisingly, EuADC does not show any photoluminescence under irradiation with UV light of different wavelengths. Similar to SrADC, EuADC exhibits a negative thermal volume expansion below room temperature with a volume expansion coefficient αV=?9.4(12)×10?6 K?1.