caa a22 4500 463239938 CHVBK 20180405153309.0 cr unu---uuuuu 170326e20070701xx s 000 0 eng 10.1007/s10947-007-0099-4 doi (NATIONALLICENCE)springer-10.1007/s10947-007-0099-4 Polymorphic transformations of C26H54 and C28H58 n -paraffins as typical rotator substances [Elektronische Daten] [I. Gnatyuk, N. Platonova, G. Puchkovskaya, E. Kotelnikova, S. Filatov, J. Baran, M. Drozd] Thermal deformations and polymorphic transformations of two long-chain evennumbered normal paraffins C26H54 and C28H58 were studied by thermal X-ray diffraction (temperature step is tenths of a degree), infrared spectroscopy (temperature step is 1-5°), and differential scanning calorimetry (temperature step is 2° in a sample heating melt cooling mode. The samples are characterized by high homologous purity (99.0%) and belong to so-called "boundary” n-paraffins. The starting C26H54 n-paraffin sample is a triclinic modification at room temperature (Tc cryst). When quickly cooled, the melt crystallizes as the triclinic Tc cryst and monoclinic monolayer 1M cryst forms (two-phase mixture Tc cryst + 1M cryst). The starting C28H58 n-paraffin sample is a double-layer monoclinic modification 2M cryst at room temperature. Crystallization from hexane or slow cooling of a melt leads to a monolayer monoclinic form 1M cryst. Thermal deformations and temperature ranges of existence of the crystalline forms (Tc cryst, 1M cryst, and 2M cryst), low-temperature rotator crystalline orthorhombic form (Or rot.1), and high-temperature rotator crystalline hexagonal (H rot.2) phases of these n-paraffins were evaluated from changes in their diffraction patterns and unit cell parameters. The molecular structure and the conformational composition of these n-paraffins in different states were found from their IR spectra. Differential scanning calorimetry (DSC) was used to determine the phase transition temperature. Thermal X-ray diffraction, IR, and DSC data agree well with one another. Springer Science+Business Media, Inc., 2007 normal even long-chain n -paraffins nationallicence phase transformations nationallicence crystalline and rotator crystalline states nationallicence thermal X-ray diffraction nationallicence IR spectroscopy nationallicence differential scanning calorimetry nationallicence Gnatyuk I. Institute of Physics, National Academy of Sciences of Ukraine, Kiev aut Platonova N. St. Petersburg State University, St. Petersburg aut Puchkovskaya G. Institute of Physics, National Academy of Sciences of Ukraine, Kiev aut Kotelnikova E. St. Petersburg State University, St. Petersburg aut Filatov S. St. Petersburg State University, St. Petersburg aut Baran J. Institute of Low Temperatures and Structural Studies, Polish Academy of Sciences, Wroclaw, Poland aut Drozd M. Institute of Low Temperatures and Structural Studies, Polish Academy of Sciences, Wroclaw, Poland aut Journal of Structural Chemistry Springer US 48/4(2007-07-01), 654-665 0022-4766 48:4<654 2007 48 10947 https://doi.org/10.1007/s10947-007-0099-4 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10947-007-0099-4 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Gnatyuk I. Institute of Physics, National Academy of Sciences of Ukraine, Kiev aut NATIONALLICENCE 700 1- Platonova N. St. Petersburg State University, St. Petersburg aut NATIONALLICENCE 700 1- Puchkovskaya G. Institute of Physics, National Academy of Sciences of Ukraine, Kiev aut NATIONALLICENCE 700 1- Kotelnikova E. St. Petersburg State University, St. Petersburg aut NATIONALLICENCE 700 1- Filatov S. St. Petersburg State University, St. Petersburg aut NATIONALLICENCE 700 1- Baran J. Institute of Low Temperatures and Structural Studies, Polish Academy of Sciences, Wroclaw, Poland aut NATIONALLICENCE 700 1- Drozd M. Institute of Low Temperatures and Structural Studies, Polish Academy of Sciences, Wroclaw, Poland aut NATIONALLICENCE 773 0- Journal of Structural Chemistry Springer US 48/4(2007-07-01), 654-665 0022-4766 48:4<654 2007 48 10947 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer