Shoichi Okouchi

DYNAMICS OF HYDRATION OF ALCOHOLS AND DIOLS IN AQUEOUS SOLUTIONS

The 17 O NMR spin–lattice relaxation times, T 1 , of the solvent water in aqueous solutions of nine alcohols and five diols have been determined as a function of the concentration at 25°C. For the alcohol solutions, the concentration dependence of T 1 has been determined in the temperature range from 1 to 50°C. The value of n h [(τ c h / τ c 0 )-1] which has been obtained from the concentration dependence of T 1 has been defined as the dynamic hydration number (n DHN ). The values of the coordination numbers n h , have been estimated on the basis of the water-accessible surface areas (ASA) of the solute molecules. The rotational correlation times, τ c h , of water molecules around the solute molecules have been estimated and compared with that of pure water τ c 0 . The value of τ c h /τ c 0 =2.22 for Bu t OH at 25°C is the largest among the solutes investigated. The τ c h /τ c 0 values of the n-alcohols and diols increase with increasing ASA and become almost constant. The τ c h /τ c 0 values decrease with increasing temperature and approach constant value above 40°C. The temperature dependence of τ c h /τ c 0 for Bu t OH is the largest. The activation energy of τ c h for n-alcohols has the maximum value at ASA≈240 A 2 . These results are discussed by considering the molecular sizes. The τ c h /τ c 0 value for a diol was smaller than that of the corresponding n-alcohol. This result supports the concept that hydrophobic hydration is distributed by the OH groups of the solute molecules. The thermodynamic properties of hydration for n-alcohols, butanol isomers and diols are linearly dependent on their n DHN .

Hydration of amines, diamines, polyamines and amides studied by NMR

The spin–lattice relaxation times, T1, of natural abundance H217O have been measured for aqueous solutions of nine amines, five diamines, two polyamines and five amides, as a function of the concentration at 25 °C. The water-accessible surface areas of the solute molecules were calculated. The coordination number, nh, and the rotational correlation times, τhc, of water molecules around the solute molecules were estimated and compared with that of pure water τ0c. The value of τhc/τ0c= 2.02 for tert-butylamine is the largest and that of τhc/τ0c= 0.97 for urea the smallest obtained. The value of nh(τhc/τ0c– 1) was defined as the dynamic hydration number (DHN).The partial molar volumes and the partial molar heat capacities for these homologues at infinite dilution are linearly dependent on their DHN.

Progressive increase in minimum proton exchange rate with maturation of liquor

Abstract Proton exchange rate measurement was carried out by 17O-NMR spectroscopy using mother liquors of malt (aged for 0 to 15 years) and grain (aged for 0 to 8 years) whiskies, and of shochu (aged for 1 to 21 years) and awamori(aged for 0 to 10 years) of Japanese traditional spirituous liquor, and commercially available whiskies (aged for 5 to 21 years) and brandies (aged for 5 to 45 years). Through the examination of proton exchange rate based on 17O-NMR half width - pH curve plots, it has been found that the minimum proton exchange rate increases as the period of maturation of liquor becomes longer.

Prediction of environmental parameters by adsorbability index: Water solubilities of hydrophobic organic pollutants

The adsorbability index proposed by Abe et al. to predict the activated carbon adsorption of organic compounds from aqueous solutions was found to be an effective parameter for predicting the water solubilities of 265 hydrophobic organic pollutants which were classified into 118 aliphatic compounds and 88 mono- and 59 polynuclear aromatic compounds; and, furthermore, for predicting the total molecular surface areas of these compounds.

Photochemical behavior of mercury ore in water

Abstract The photochemical behavior of mercury ore (cinnabar) in water was studied using a blacklight lamp as a substitute of sunlight. The mercury ore was photosolubilized in water as mercuric ion, and metallic mercury was then volatilized from the aqueous suspension of mercury ore by photoirradiation. The photosolubilization of the mercury ore and the mercury volatilization were enhanced by the presence of an electrolyte in suspension. From the results of chemical analysis of the aqueous suspension after the photoirradiation, it appears that the mercury sulfide in the ore is dissociated into mercuric ions and free sulfur in water by photoexcitation, and hence mercury ore is solubilized into water. Furthermore, the oxidation of the free sulfur into sulfate ions via polythionic acid results in the reduction of mercuric ions to metallic mercury; hence, the metallic mercury is volatilized.

Volatility of mercury in water

Abstract The rate of volatilization of mercury and oxygen from the aqueous phase to the gas phase was studied by bubbling with nitrogen. The ratio, KLHg/KLO2, of the mass transfer coefficient of mercury to that of oxygen was determined in the temperature range 278–308 K. The ratio of 0.94 ± 0.08 which was obtained was found to be higher than that for 19 other substances, such as krypton, radon, ethylene, methylene chloride and benzene, quoted in the literature. Thus, mercury was found to be readily volatilized from the aqueous to the gas phase, despite having a much lower vapor pressure and a higher molecular weight than the other substances.

Hydroxylation of phenolic compounds under the condition of ultrasound in aqueous solution

Abstract Ultrasound (200 kHz)-assisted hydroxylation of phenolic compounds, such as phenol, 4-methyl phenol, 4-hydroxyanisol, 2-naphthol, catechol, resorcinol, 3-t-butyl-4-hydroxyanisole, 3-methyl-4-hydroxyanisole, in aqueous solution was successfully carried out in 12–18 h to give the hydroxylated products which were identified as their respective acetates.

Calorimetric Evaluation of Antifungal Activity of TBZ.

カビの発育熱を熱量計で測定し,その発育熱の変化から,TBZのA.nigerに対する抗カビ活性を検討した.サーモグラムと形態観察により,カビの発熱はカビの形態変化の過程で,菌糸の成長,すなわち細胞増殖による代謝熱であることが示された.さらに,この発熱は培地に添加したTBZの濃度が高くなるにつれて,時間的に遅れることを認めた.その遅れ時間をTAKAHASHIらのバクテリア増殖抑制モデルに適用して解析を行ったところ,カビの発育速度が1/2になるTBZ濃度[I]1/2,さらに最小発育防止濃度MICを定量的に決定することができた.本法により求めたMIC値は従来法によるMIC値と良く一致しており,本法の有効性が確認された.

Transfer rates of chlorofluorocarbons 11, 12, and 113 across air/water interface

The transfer rates of chlorofluorocarbons (CFCs), 11 (CC13F), 12 (CC12F2), and 113 (CC12FCC1F2), were concurrently measured with the oxygen-reaeration rate under various mixing conditions which were controlled by mass transfer in water. The ratios of the transfer rate constant to the oxygen-reaeration rate constant were 0.64 ± 0.03 for CFC-11, 0.67 ± 0.03 for CFC-12, and 0.61 ± 0.03 for CFC-113. If the oxygen-reaeration rate constant or oxygen-transfer rate constant in a real water body is available, multiplying its value by these ratios permits the determination of the transfer rate of CFCs across air/water in that water body.