In fast catalytic pyrolysis of eucalyptus woody biomass, zeolites mainly enhanced the formation of both oxygenated and non-oxygenated aromatic hydrocarbons. Notably, H-ZSM-5 with a low Si/Al2 ratio and H-Beta zeolites were highly efficient at catalyzing the formation of non-oxygenated aromatic compounds, while H-ZSM-5 with a high Si/Al2 ratio, H-mordenite, and USY (ultra-stable Y) were moderately efficient at catalyzing the formation of phenolic compounds as well as non-oxygenated aromatics. There seems to be an inverse correlation between yields of non-oxygenated aromatic compounds and those of phenolic compounds. Strong solid acidity favored deoxygenation. Moderate solid acidity favored the formation of phenolic compounds. Micropore structure also affected type and distribution of products. The addition of Cr, Mn, Fe, Cu, Zn, Mo, Ag, Re, or Pt to USY improved the yield of phenol. Ag- or Pt-modification improved the yield of total phenolic compounds (phenol + methylphenols + dimethylphenols).
ε-Caprolactone (CL) was polymerized by using N-methyldiethanolamine as an initiator followed by chain extension with hexamethylene diisocyanate afforded PCL-based poly(ester-urethane)s (PCLUs) with equally spaced tertiary amine groups. Treatment of the PCLUs with iodomethane converted tertiary amine groups to quaternary ammonium groups to give cationic ionomers. The thermal and mechanical properties of the obtained polymers were investigated.
In this work, the synthesis and the physical properties of poly(L-lactide-urethane)s (PLLAU) with ionic groups were studied. Using dimethylolpropionic acid (DMPA) as an initiator, L-lactide (L-LA) was polymerized in the presence of Sn(Oct)2 to give hydroxytelechelic PLLA (PLLA-diol) bearing a carboxy group at the center of the polymer chain. Chain extension of the in situ generated PLLA-diol with hexamethylene diisocyanate (HMDI) afforded PLLAU having equally separated carboxy groups. PLLAU was treated with various metal acetates to give ionomers, and their thermal and mechanical properties were investigated.
We fabricated an all-solid-state lithium ion battery with magnesium hydride (MgH2) anode which was catalyzed by doping 5mol% Nb2O5 (95MgH2-5Nb2O5) to increase low first-coulombic-efficiency of MgH2 anode. The catalyzed MgH2 (99MgH2-1Nb2O5, 95MgH2-5Nb2O5) and solid electrolyte were independently synthesized by mechanical ball milling. In order to investigate the hydrogen desorption temperature of pristine MgH2, 99MgH2-1Nb2O5 and 95MgH2-5Nb2O5, thermal desorption mass spectroscopy was carried out. In addition, the charge and discharge measurement for 95MgH2-5Nb2O5 was carried out at 100 ℃ and at current density of 0.05 mA cm-2 and 0.15 mA cm-2. As a result, the following results were revealed. (1) The hydrogen desorption temperature decreases with increasing Nb2O5 contents and columbic efficiency increases with increasing Nb2O5 contents. Therefore, the columbic efficiency increases with decreasing hydrogen desorption temperature. (2) Rate properties of MgH2 are also improved with increasing Nb2O5 contents. (3) Effect of Nb2O5 additives on anode properties of MgH2 is clearer upon the Li extraction reaction than that upon the Li insertion reaction due to thermodynamically and electrochemically reasons. (4) Upon the Li insertion reaction, effect of Nb2O5 additives become clearer at current density of 0.15 mA cm-2 than that of 0.05 mA cm-2. Thus, the anode properties of MgH2 are improved by adding Nb2O5.
Measurements of temperature and gas generation during fast pyrolysis of lignocellulosic biomass in paying attention to the effects of the setting temperature TS and type of biomass have been studied experimentally. From the time courses of the temperature at the center TC of a cornel particle, there could be two regions due to the endothermic reactions of biomass during pyrolysis and exothermic char formation from tar. Between these two regions, the endothermic reactions of biomass during pyrolysis could be completed at about 690 K. The exothermic behavior was observed at TS < 873 K. On the other hand, the maximum generated gas flow rate Gmax increased dramatically at TS > 773 K due to both the endothermic reactions of biomass during pyrolysis and the decomposition of generated tar. From the time courses of the temperature at the center TC of the fragment of palm kernel shell (PKS), the slight endothermic and obvious exothermic behaviors were observed. The maximum difference between the TC and the ambient temperature TA at the exothermic region for the PKS fragment was higher than that for the cornel particle. The maximum gas flow rate for the PKS fragment was larger than that for the cornel particle.
The gasification characteristics of five amino acids, i.e., glycine, alanine, valine, leucine, and proline, in supercritical water were compared. A tubular reactor was employed for the gasification reactions in the temperature range of 500 to 650 ℃ with a reaction pressure of 25 MPa and residence time of 86-119 s. The gasification characteristics of glycine, alanine, and leucine were determined to be similar, while the gasification rate of valine was much slower. The activation energies of valine and proline were lower than those of glycine, alanine, and leucine. These behaviors are attributed to the stability of the transition state for carboxyl radical production and secondary radical produced from valine.