n-pentanol at high pressures: Rotational isomerism in the liquid phase and the liquid-solid phase transition

2006 ◽  
Vol 124 (4) ◽  
pp. 044508 ◽  
Author(s):  
V. G. Baonza ◽  
M. Taravillo ◽  
A. Cazorla ◽  
S. Casado ◽  
M. Cáceres
Keyword(s):  
Phase Transition ◽  
Liquid Phase ◽  
High Pressures ◽  
Solid Phase ◽  
Rotational Isomerism ◽  
Solid Phase Transition

scholarly journals Response of the Surface Phase Transition to an Abrupt Pressure Change: Comparative Study of the 2D Gas–Liquid and 2D Fluid–Solid Phase Transitions

1998 ◽  
Vol 16 (5) ◽  
pp. 391-404 ◽  
Author(s):  
Yosihito Kitayama ◽  
Yosinobll Sakai ◽  
Hiromu Asada
Keyword(s):  
Phase Transition ◽  
Liquid Phase ◽  
Time Constant ◽  
Solid Phase ◽  
Pressure Change ◽  
Fast Decay ◽  
Liquid Phase Transition ◽  
Decay Component ◽  
Slow Decay ◽  
Solid Phase Transition

The manner in which gaseous CH4 and N2 respond to an abrupt pressure change through adsorption and desorption on exfoliated graphite held at a temperature between 77 K and 90 K has been studied with particular emphasis on the role of the 2D (two-dimensional) Gas–Liquid phase transition of the second layer of adsorbed CH4 and of the 2D Fluid–Solid phase transition of adsorbed N2. The pressure relaxation was found to consist of two exponential decay components: a fast one and a slow one. For CH4, the 2D Gas–Liquid phase transition is involved in the fast decay component with a time constant of 2–3 s, while the slow decay component with a time constant of 7–40 s is minor and has been attributed to ripening or coalescence processes in the adsorbed phase. In contrast, the 2D Fluid–Solid phase transition of N2 involves both the fast decay component with a time constant of 2–3 s and the slow decay component with a time constant of 14–16 s, both having nearly equal magnitudes. The difference in the pressure response between the two phase transitions is discussed.

scholarly journals Liquid-liquid phase separation of full-length prion protein initiates conformational conversion in vitro

2020 ◽  
Author(s):  
Hiroya Tange ◽  
Daisuke Ishibashi ◽  
Takehiro Nakagaki ◽  
Yuzuru Taguchi ◽  
Yuji O. Kamatari ◽  
...  
Keyword(s):  
Phase Transition ◽  
Phase Separation ◽  
Liquid Phase ◽  
Prion Protein ◽  
Solid Phase ◽  
Terminal Region ◽  
Liquid Phase Separation ◽  
Solid Phase Transition ◽  
Liquid Liquid Phase Separation

AbstractPrion diseases are characterized by accumulation of amyloid fibrils. The causative agent is an infectious amyloid that is comprised solely of misfolded prion protein (PrPSc). Prions can convert PrPC to proteinase-resistant PrP (PrP-res) in vitro; however, the intermediate steps involved in the spontaneous conversion remain unknown. We investigated whether recombinant prion protein (rPrP) can directly convert into PrP-res via liquid-liquid phase separation in the absence of PrPSc. We found that rPrP underwent liquid-liquid phase separation at the interface of the aqueous two-phase system (ATPS) of polyethylene glycol (PEG) and dextran, whereas single-phase conditions were not inducible. Fluorescence recovery assay after photobleaching revealed that the liquid-solid phase transition occurred within a short time. The aged rPrP-gel acquired proteinase-resistant amyloid accompanied by β-sheet conversion, as confirmed by western blotting, Fourier transform infrared spectroscopy, and Congo red staining. The reactions required both the N-terminal region of rPrP (amino acids 23-89) and kosmotropic salts, suggesting that the kosmotropic anions may interact with the N-terminal region of rPrP to promote liquid-liquid phase separation. Thus, structural conversion via liquid–liquid phase separation and liquid–solid phase transition are intermediate steps in the conversion of prions.

scholarly journals Low Temperature and High-Pressure Study of Bending L-Leucinium Hydrogen Maleate Crystals

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1575
Author(s):  
Kseniya D. Skakunova ◽  
Denis A. Rychkov
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Low Temperatures ◽  
High Pressures ◽  
Solid Phase ◽  
Extreme Conditions ◽  
Pressure Impact ◽  
Solid Phase Transition ◽  
High Pressure Study ◽  
Crystal Fracture

The polymorphism of molecular crystals is a well-known phenomenon, resulting in modifications of physicochemical properties of solid phases. Low temperatures and high pressures are widely used to find phase transitions and quench new solid forms. In this study, L-Leucinium hydrogen maleate (LLHM), the first molecular crystal that preserves its anomalous plasticity at cryogenic temperatures, is studied at extreme conditions using Raman spectroscopy and optical microscopy. LLHM was cooled down to 11 K without any phase transition, while high pressure impact leads to perceptible changes in crystal structure in the interval of 0.0–1.35 GPa using pentane-isopentane media. Surprisingly, pressure transmitting media (PTM) play a significant role in the behavior of the LLHM system at extreme conditions—we did not find any phase change up to 3.05 GPa using paraffin as PTM. A phase transition of LLHM to amorphous form or solid–solid phase transition(s) that results in crystal fracture is reported at high pressures. LLHM stability at low temperatures suggests an alluring idea to prove LLHM preserves plasticity below 77 K.

Solidification of Ionic Liquids: Theory and Techniques

2010 ◽  
Vol 63 (4) ◽  
pp. 544 ◽  
Author(s):  
Anja-Verena Mudring
Keyword(s):  
Phase Transition ◽  
Ionic Liquid ◽  
Ionic Liquids ◽  
Solid Phase ◽  
Soft Materials ◽  
Separation Science ◽  
Vast Number ◽  
Plastic Crystals ◽  
Thermal Fluids ◽  
Solid Phase Transition

Ionic liquids (ILs) have become an important class of solvents and soft materials over the past decades. Despite being salts built by discrete cations and anions, many of them are liquid at room temperature and below. They have been used in a wide variety of applications such as electrochemistry, separation science, chemical synthesis and catalysis, for breaking azeotropes, as thermal fluids, lubricants and additives, for gas storage, for cellulose processing, and photovoltaics. It has been realized that the true advantage of ILs is their modular character. Each specific cation–anion combination is characterized by a unique, characteristic set of chemical and physical properties. Although ILs have been known for roughly a century, they are still a novel class of compounds to exploit due to the vast number of possible ion combinations and one fundamental question remains still inadequately answered: why do certain salts like ILs have such a low melting point and do not crystallize readily? This Review aims to give an insight into the liquid–solid phase transition of ILs from the viewpoint of a solid-state chemist and hopes to contribute to a better understanding of this intriguing class of compounds. It will introduce the fundamental theories of liquid–solid-phase transition and crystallization from melt and solution. Aside form the formation of ideal crystals the development of solid phases with disorder and of lower order like plastic crystals and liquid crystals by ionic liquid compounds are addressed. The formation of ionic liquid glasses is discussed and finally practical techniques, strategies and methods for crystallization of ionic liquids are given.

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