Hiroshi Matsuo

Bio: Hiroshi Matsuo is an academic researcher from Ritsumeikan University. The author has contributed to research in topics: Solubility & Activity coefficient. The author has an hindex of 4, co-authored 5 publications receiving 88 citations.

A high‐pressure polymorph of l‐α‐leucine

Abstract: A new high-pressure phase of the title amino acid (systematic name: 2-ammonio-4-methyl­penta­noate), C6H13NO2, is reported, with one molecule per asymmetric unit, in contrast to the atmospheric pressure phase, (I), reported by Harding & Howieson [Acta Cryst. (1976). B32, 633–634], which has two mol­ecules in the asymmetric unit. The packing consists of a double layer structure, similar to those of (I) and other amino acids with non-polar side chains.

Effects of pressure and temperature on the solubility of monosodium L-glutamate monohydrate in water

Abstract: The solubility of monosodium L-glutamate monohydrate (MSG.H2O) in water was measured at pressures in the range of 0.10-300MPa and 298.15K. The density of MSG solution at high concentrations and heat of solution at saturated concentration were also measured at atmospheric pressure. The solubility, ms, increased with increasing pressure and the pressure coefficient, Θp, [≊(∂ In ms,∂ p)T] at 0.10 MPa was (2.0 ± 0.1) × 10-10Pa-1. It agrees well with (2.1 ±0.2)× 10-10 Pa-1 thermodynamically estimated using the partial molar volume, the activity coefficient of the solute in solution, and the molar volume of the crystal. The excellent agreement at 0.10MPa gives us confidence in the solubility data at higher pressures. The heat of solution data and other pertinent values were used to calculate the temperature coefficient of solubility, ΘT [≊ (∂ In ms/∂(1/T))p], by a thermodynamic equality. The resulting ΘT compares well with the data directly measured by Ogawa.

Solubility of Amino Acids: Influence of the pH value and the Addition of Alcoholic Cosolvents on Aqueous Solubility

Abstract: The solubility of dl-methionine in pure water has been measured in a temperature range of 293.15−353.15 K by means of on-line attenuated total reflection−Fourier transform infrared (ATR−FTIR) spectroscopy. These experimental data, as well as literature data for the solubility of glycine and dl-alanine in aqueous and alcohol solutions, were modeled using the PC−SAFT equation of state. Pure-component parameters for glycine, dl-alanine, and dl-methionine were fitted to the vapor pressures and to the densities of their aqueous solutions. Only one temperature-independent binary parameter is required for each system. The solubility of amino acids in water−alcohol mixtures (ternary systems) was then predicted without fitting any additional parameters. The results of the prediction correspond well to literature data. To retrieve the pH dependency, the solubility of dl-methionine in different HCl and NaOH solutions in the pH range of 1.5−9.5 was determined via gravimetric measurements. Using the knowledge of the a...

High-pressure polymorphism in amino acids

Abstract: Pressure up to 10 GPa is a powerful method for studying polymorphism in organic crystal structures, and this review surveys work carried out on high-pressure polymorphism in amino acids. High-pressure polymorphs have been established crystallographically for glycine, alanine, serine, cysteine and leucine. Phase transitions can be driven by the avoidance of very short intermolecular contacts or by promotion of a more stable molecular conformation. Experimental methods are also briefly surveyed, along with three methods that have proved very helpful in the analysis of high-pressure polymorphs, namely the PIXEL method for calculation of intermolecular energies, topological analysis with Voronoi–Dirichlet partitioning and Hirshfeld surfaces for gaining a graphical overview of intermolecular interactions.

Experimental Methods for Phase Equilibria at High Pressures

Abstract: Knowledge of high-pressure phase equilibria is crucial in many fields, e.g., for the design and optimization of high-pressure chemical and separation processes, carbon capture and storage, hydrate formation, applications of ionic liquids, and geological processes. This review presents the variety of methods to measure phase equilibria at high pressures and, following a classification, discusses the measurement principles, advantages, challenges, and error sources. Examples of application areas are given. A detailed knowledge and understanding of the different methods is fundamental not only for choosing the most suitable method for a certain task but also for the evaluation of experimental data. The discrepancy between the (sometimes low) true accuracy of published experimental data and the (high) accuracy claimed by authors is addressed. Some essential requirements for the generation of valuable experimental results are summarized.