Transformation of methane formation sites into methanol formation ones during CO---H2 reaction over Pd/CeO2 in its SMSI state

The phenomena of induction period of methanol formation, observed in CO---H₂ reaction over Pd/CeO₂ catalysts under SMSI state, was investigated in depth. The magnitude of the induction period was dependent on the extent of SMSI, and higher temperature H₂ reduction lengthened it accompanied with the increase of the number of active sites for methane formation. On the contrary, by the pretreatment of SMSI surface with water vapor, this induction period almost disappeared with the drastic decrease of methane formation rate. These results indicate that methane formation sites would be transformed into methanol formation sites by the oxidation of water vapor formed during CO---H₂ reaction. Infrared spectroscopic investigation of adsorbed CO after various pretreatments indicated that during the induction period thin layers of reduced ceria, which preferentially covered Pd(1 1 1) plane under SMSI state, were removed from the Pd(1 1 1) plane by formed water vapor during CO---H₂ reaction. It was concluded that Pd(1 1 1) plane adjacent to ceria would be the efficient active sites for methanol formation.     

A fundamental study on recovery of copper with a cation exchange membrane: Part 1 — Ion exchange equilibria between cupric and hydrogen ions

It is possible to concentrate metal ion against the gradient of its concentration through a cation exchange membrane. The membrane has a high ion exchange capacity and is hydrophilic, therefore a rapid transfer rate of ions is expected. Ion exchange equilibrium data between cupric and hydrogen ions for sulfuric and nitric acid systems are obtained and analyzed quantitatively for concentrations of dissociated cupric and hydrogen ions.     

Hydration of phosphorylcholine groups attached to highly swollen polymer hydrogels studied by thermal analysis

Hydration of polymer chains plays a key role for determining the extent of protein adsorption on polymeric materials. Here we investigated the hydration of poly(2-methacryloyloxyethyl phosphorylcholine (MPC)) chains, which resist protein adsorption and following cell adhesion effectively. The hydration was compared with that of poly(methoxy oligo(ethylene glycol)-monomethacrylate (Me(EG)_nMA)) chains, which also have hydrophilic units. The poly(MPC) and poly(Me(EG)_nMA) hydrogels with equilibrium water contents (EWCs) in the range from 86 to 97 wt% were prepared. By differential scanning calorimetric measurements, water in both the hydrogels was classified into two states: freezable and nonfreezable water. The poly(MPC) hydrogels had larger nonfreezable water than the poly(Me(EG)_nMA) hydrogels even when their EWCs were similar, which indicated the higher hydrating ability of poly(MPC) chains. We suggested that the difference in the amount of nonfreezable water around polymer chains may influence the degree of protein adsorption resistance after contact with body fluid for a long period.     

Synthesis of well-defined random and block copolymers of 2-(1-adamantyl)-1,3-butadiene with isoprene via anionic polymerization

Anionic copolymerization of a mixture of 2-(1-adamantyl)-1,3-butadiene (1) and isoprene was carried out with sec-BuLi in cyclohexane at 40 °C. The resulting random copolymers possessed the predicted compositions and molecular weights based on the molar ratios between comonomers and initiator and the narrow molecular weight distributions. The both repeating units of poly(1) and polyisoprene contained 1,4-rich microstructures. The resulting copolymer having 1,4-polydiene units was completely converted into a novel saturated terpolymer, poly(ethylene-ran-propylene-ran-1-vinyladamantane) (P(E-ran-P-ran-VAd) by the hydrogenation with p-toluenesulfonhydrazide. The T_g values of hydrogenated polymers could be changed from ?66 °C to 122 °C by the feed molar ratio of comonomers. A novel well-defined saturated ABA triblock copolymer possessing all alternating polymer segments, P(E-alt-VAd)-b-P(E-alt-P)-b-P(E-alt-VAd), was similarly synthesized by the sequential copolymerization of 1 and isoprene and the following hydrogenation. The microphase separation behaviors of this new thermoplastic elastomer carrying bulky adamantyl groups in the hard end segments were analyzed by dynamic mechanical analysis and transmission electron microscopy.     

Chemical conversion and liquid–liquid extraction of 5‐hydroxymethylfurfural from fructose by slug flow microreactor

A dehydration of fructose in the water/methyl isobuthyl ketone (MIBK) biphasic system can yield 5‐hydroxymethylfurfural (HMF) to be successfully extracted into the organic MIBK phase. The HMF production and yield in MIBK phase was discussed by using a simplified model taking into consideration of the slug flow. The extraction resistance of HMF across the interface between water and MIBK depended on the line velocity and the flow rate ratio. It was likely that the velocity field generated in the slug flow contributed to an increase in the mass transfer of HMF. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2135–2143, 2016