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We developed a membrane reactor that can produce high-purity hydrogen in one step from methylcyclohexane. This membrane reactor combined a hydrogen-selective amorphous silica membrane prepared with dimethoxydiphenylsilane and oxygen and employing counter-diffusion chemical vapor deposition, and Pt/Al 2 O 3 catalyst. The silica membrane showed excellent hydrogen permeance at 573 K of the order of 10 -6 mol m -2 s -1 Pa -1 and high hydrogen/sulfur hexafluoride permselectivity of around 10 4 . The membrane reactor exhibited equilibrium shifts as expected under reaction temperatures ranging from 473 to 553 K and reaction pressures ranging from 0.1 to 0.25 MPa, and these performances were successfully predicted using a simulation model, which was also developed in this study. Finally, we demonstrated that hydrogen with purity as high as 99.95% was produced from methylcyclohexane in the membrane reactor without using carrier gas or sweep gas.

The cyclic process of biosynthesis and degradation of poly(3‐hydroxyalkanoate) (PHA) was studied in Alcaligenes eutrophus under conditions of nitrogen‐limitation of growth. A. eutrophus cells, which had accumulated poly(3‐ydroxybutyrate) (PHB) of 55 wt% content within cells from butyric acid, were transferred into a nitrogen‐free medium containing pentanoic acid as the sole carbon source and cultivated at 30°C and pH 7.5. The content of PHB in A. eutrophus cells decreased with time, whereas a copolyster of 3‐hydroxybutyrate (HB) and 3‐hydroxyvalerate (HV) units, P(HB‐co‐HV), was accumulated in the presence of pentanoic acid. Conversely, when A. eutrophus cells with 50 wt% content of P(HB‐co‐56% HV) were incubated in a nitrogen‐free medium containing butyric acid, the content of P(HB‐co‐56% HV) decreased with time, whereas PHB was accumulated. These results indicate the cyclic nature of PHA metabolism in A. eutrophus under these conditions.

The cyclic process of biosynthesis and degradation of poly(3-hydroxyalkanoate) (PHA) was studied in Alcaligenes eutrophus under conditions of nitrogen-limitation of growth. A. eutrophus cells, which had accumulated poly(3-hydroxybutyrate) (PHB) of 55 wt% content within cells from butyric acid, were transferred into a nitrogen-free medium containing pentanoic acid as the sole carbon source and cultivated at 30 degrees C and pH 7.5. The content of PHB in A. eutrophus cells decreased with time, whereas a copolyester of 3-hydroxybutyrate (HB) and 3-hydroxyvalerate (HV) units, P(HB-co-HV), was accumulated in the presence of pentanoic acid. Conversely, when A. eutrophus cells with 50 wt% content of P(HB-co-56% HV) were incubated in a nitrogen-free medium containing butyric acid, the content of P(HB-co-56% HV) decreased with time, whereas PHB was accumulated. These results indicate the cyclic nature of PHA metabolism in A. eutrophus under these conditions.

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