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

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

内視鏡的ドレナージが有効であった胃壁膿瘍を合併した胃迷入膵の１例

　症例は30歳代女性．３日前から心窩部痛が出現し，徐々に増悪してきたため当院を受診した．血液検査でWBC 15,120/μl，CRP 2.95mg/dl と炎症反応上昇を認め，腹部超音波検査で胃幽門前庭部前壁に約3.5cm の粘膜下腫瘍様隆起を認めた．腫瘍内部はechogenic particles の混在する液体の貯留を認めた．腹部造影CT 検査では，胃前庭部から胃体部前壁にリング状の造影効果を伴う著明な壁肥厚を認めた．以上より胃壁膿瘍と診断した．胃前庭部前壁の弾性硬のやや発赤した粘膜下腫瘍様隆起に対して，超音波内視鏡下穿刺術（EUS-FNA）を行った．粘稠な白色液体の流出を認め，膿瘍を示唆する所見であった．絶食・点滴・抗生剤投与による保存的加療を施行後，速やかに腹部症状は消失し，EUS-FNA 施行後５日目に退院した．４か月後，病変は上部内視鏡検査で頂部に陥凹を有する腫瘍に形態変化を認め，さらに縮小傾向であった．また，腹部超音波検査では粘膜下層内に約５mm 大の嚢胞性領域とそれに接する約４mm 大の境界不明瞭な低エコー域，不整な固有筋層の肥厚を認め，胃迷入膵の所見であった．以上より，胃壁膿瘍を合併した胃迷入膵と診断した．現在，再発なく当科で経過観察中である．胃壁膿瘍を合併した胃迷入膵の報告は非常に稀であり，貴重な症例と考えられた．　Here, we report a case of gastric wall abscess in aberrant pancreas. A 30-yearold woman visited our hospital for epigastric pain. Routine hematological examination showed increased white blood cell count and biochemical tests revealed elevated C reactive protein levels. Abdominal ultrasound revealed a submucosal tumor that appeared as a hypoechoic heterogenous mass in the stomach. Abdominal computed tomography revealed a thickened gastric wall with a low-density area. This mass was diagnosed as a gastric wall abscess, which was treated with endoscopic ultrasound-guided fine needle aspiration and conservative therapy with antibiotics. The patient’s pain resolved after the treatment. Four months after the episode, follow-up examinations showed that the submucosal tumor had changed to a small submucosal mass with depression. This lesion was diagnosed as an aberrant pancreas. Thus, the final diagnosis was a gastric wall abscess in the aberrant pancreas. This patient was followed up for one year following this episode with no incidence of recurrence