Characterization and hydrodesulfurization activity of CoMo catalysts supported on sol-gel prepared Al2O3

A series of CoMo/Al2O3 catalysts was prepared by impregnation on a series of alumina powders synthesized by the sol-gel method with different hydrolysis ratios R (defined as [H2O] / [aluminum-tri-sec-butoxide (ASB)]; R = 3, 4, ..., 12, 13). The oxide precursors were characterized and subsequently tested in the hydrodesulfurization (HDS) of thiophene, dibenzothiophene (DBT), and 4,6-dimethyldibenzothiophene (4,6-DMDBT). Mainly due to their large pore diameters of ca. 6 nm, the catalysts prepared from the alumina with hydrolysis ratio R = 7 ~ 10 showed higher HDS activity compared with the activities of the other prepared catalysts. The effect of the pore diffusional limitation was more significant than expected, due to the ink-bottle shape of the pores of the prepared catalysts with hydrolysis ratio R 10. Due to highly dispersed CoMo active phase, the HDS activity of the prepared catalysts with hydrolysis ratio R = 8 and 9 for thiophene was similar to that of a reference industrial catalyst that was designed and manufactured for deep HDS of diesel fuel fractions. Furthermore, the HDS activity of the prepared catalysts with hydrolysis ratio R > 5 for DBT was higher than that of the reference industrial catalyst. For 4,6-DMDBT, however, the reference industrial catalyst showed higher HDS activity compared with the activities of the prepared catalysts. Relatively high HDS activity was observed for the prepared catalysts with R = 9 and 10 with cylindrical pore shape and with a high proportion of strong acid sites. The strong acidity supposedly enhanced the hydrogenation activity of the catalysts that was essential for the HDS of 4,6-DMDBT

X-Ray Analysis Literatures 2012

2012年に出版されたX線分析に関連する文献および情報について，X線分析技術の発展に寄与し重要であると編集委員が選抜した文献を総説としてまとめた．調査対象はe-ジャーナル，webマガジンを含む学術誌18誌，制定された規格およびX線関連メーカーの新技術情報である．各雑誌について全体的な傾向および選抜したいくつかの論文に対して論評を記した．The selected literatures about advances in X-ray analysis and X-ray analysis-related information published in 2012 were reviewed on the basis of analytical chemistry, physics, techniques, optics, instrumentation and so forth. The 18 kinds of academic journals including web-magazines, Japanese Industrial Standard (JIS), and websites of companies related with X-ray tools and/or X-ray apparatus were researched. The trend of publications related to X-ray analysis for each journal was overviewed, and some of noticeable literatures were commented

X-Ray Analysis Literatures 2011

2011年に出版されたX線分析関連文献，X線に関連した情報のなかで，編集委員がX線分析技術の発展に寄与し重要であると選抜した文献を総説としてまとめた．調査対象はe-ジャーナル，web マガジンを含む学術誌20誌，制定された規格およびX線関連メーカーの新技術情報である．各雑誌について，全体的な論評，X線分析に関する傾向から，いくつかの論文について論評を記した．The selected literatures about advances in X-ray analysis and X-ray analysis-related informations published in 2011 were reviewed on the basis of analytical chemistry, physics, techniques, optics, instrumentation and so forth. The 20 kinds of academic journals including web-magagines, Japanease Industrial Standard (JIS), and websites of companies related with X-ray tools and/or X-ray apparatus were researched. The trend of publications related to X-ray analysis for each journal was overviewed, and some of noticeable literatures were commented

X-Ray Analysis Literatures 2010

本総説は，2010年に学術雑誌に掲載されたX線分析関連の論文において，注目すべき論文を厳選し紹介する．調査した学術雑誌は19件（和雑誌2件含む）であり，X線分析の発展に寄与しているものを対象としているが，分析化学の分野だけでなく，分光学や物理学の分野も網羅している．各雑誌に関して，X 線分析手法や測定された試料の傾向，分析技術や要素開発に関するトピックスの他に，特筆すべき論文には論評も記している．日本工業規格（JIS）におけるX線分析関連の規格の制定や改訂についてまとめている．X線関連メーカーのウェブサイトを紹介し，掲載している技術レポートの情報も得られる．　In this article, the interesting X-ray analysis-related literatures, which are published on academic journals during the year 2010, are summarized. The number of the researched journals is 19, including two Japanese journals, which contribute the advance of the X-ray analysis in the field not only of analytical chemistry but also of spectroscopy and physics. In every journal, the trend of the X-ray analysis methods and of the measured specimens, the topics of analytical technique and of the developed components of the X-ray analysis apparatus, and the comments for the nortable articles are mentioned. The constitution and revision of standards of X-ray analysis on Japanease Industrial Standard (JIS) are shown. The websites of the company related with X-ray tools or X-ray apparatus are also shown, and the information on technical reports is available

Subaru Hyper Suprime-Cam Survey for An Optical Counterpart of GW170817

We perform a $z$-band survey for an optical counterpart of a binary neutron star coalescence GW170817 with Subaru/Hyper Suprime-Cam. Our untargeted transient search covers $23.6$ deg$^2$ corresponding to the $56.6\%$ credible region of GW170817 and reaches the $50\%$ completeness magnitude of $20.6$ mag on average. As a result, we find 60 candidates of extragalactic transients, including J-GEM17btc (a.k.a. SSS17a/DLT17ck). While J-GEM17btc is associated with NGC 4993 that is firmly located inside the 3D skymap of GW170817, the other 59 candidates do not have distance information in the GLADE v2 catalog or NASA/IPAC Extragalactic Database (NED). Among 59 candidates, 58 are located at the center of extended objects in the Pan-STARRS1 catalog, while one candidate has an offset. We present location, $z$-band apparent magnitude, and time variability of the candidates and evaluate the probabilities that they are located inside of the 3D skymap of GW170817. The probability for J-GEM17btc is $64\%$ being much higher than those for the other 59 candidates ($9.3\times10^{-3}-2.1\times10^{-1}\%$). Furthermore, the possibility, that at least one of the other 59 candidates is located within the 3D skymap, is only $3.2\%$. Therefore, we conclude that J-GEM17btc is the most-likely and distinguished candidate as the optical counterpart of GW170817.Comment: 14 pages, 9 figures. Accepted for publication in PASJ (Publications of the Astronomical Society of Japan

Characterization and Hydrodesulfurization Activity of CoMo Catalysts Supported on Boron-Doped Sol-Gel Alumina

A series of hydrodesulfurization (HDS) catalysts was prepared by impregnation of Co and Mo on sol-gel B-Al2O3 supports with B/Al ratios of 0, 0.02, 0.04, 0.08, 0.20, 0.32, 0.49, and 0.61. The thiophene HDS and dibenzothiophene (DBT) HDS activities were both maximal for the catalyst with B/Al = 0.04, with respective values 70% and 42% higher than those for an industrial reference catalyst. These maxima in HDS activity correlated with the previously reported presence of isolated BO4 surface species. These BO4 species were responsible for a local maximum in the acidity of the B-Al2O3 supports when B/Al = 0.04. In contrast, the formation of mixed oxides (A9B2 and A2B) or B2O3 that also resulted in enhanced acidity of the B-Al2O3 supports had a detrimental effect on the HDS activity. The 4,6-dimethyldibenzothiophene (4,6-DMDBT) HDS activity over the CoMo/B-Al2O3 catalysts decreased when the B/Al ratio was increased. This was attributed to the strong direct desulfurization character of the CoMo catalysts supported on the B-Al2O3 supports, because high hydrogenation ability toward the C=C double bonds is essential prior to sulfur removal from 4,6-DMDBT. The excellent performance in the thiophene and DBT HDS of the CoMo/B-Al2O3 catalysts is particularly useful for ultra-deep HDS of light fractions