Effect of Lanthanum Doping on the reactivity of unsupported CoMoS2 catalysts

Article abstract of DOI:10.1016/j.apcata.2020.117891

In the present study, catalytic systems based on La-doping were developed to improve the activity and performance of CoMoS₂ hydrodesulfurization catalysts. Lanthanum-doped at 5, 10, or 25% of the Co content in CoMoS₂ hydrodesulfurization catalysts were synthesized through a solvothermal process. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses confirmed the catalysts were triphasic consisting of Co₉S₈, MoS₂, and La₂S_3. The La doped catalysts showed enhanced catalytic activity compared with CoMoS₂ synthesized under the same conditions. The CoMoS₂ prepared under solvothermal synthesis conditions showed a catalytic activity of 6.80 mol g^-1 s^-1, however, the La_0.05Co_0.95MoS₂ doping showed a catalytic activity of 6.51 mol g ^-1 s^-1 whereas the La_0.1Co_0.9MoS₂ and La_0.25Co_0.75MoS₂ samples showed catalytic activities of 10.7 mol g^-1 s^-1. The reaction products indicated the major reaction pathway was direct desulfurization. The La_0.25Co_0.75MoS₂ catalyst after one reaction cycle showed a lower amount of carbon, than the undoped CoMoS₂ catalyst.

Full text of DOI:10.1016/j.apcata.2020.117891

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JACC March 21, 2017
Volume 69, Issue 11
FIT Clinical Decision Making
PARADOXICAL HYPERTENSIVE ADVERSE REACTION TO NITROGLYCERINE DURING TILT TABLE
TEST UNMASKING UNDIAGNOSED PHEOCHROMOCYTOMA: A CASE REPORT
Moderated Poster Contributions
Spotlight on Special Categories Moderated Poster Theater, Poster Hall, Hall C
Sunday, March 19, 2017, 1:30 p.m.-1:40 p.m.
Session Title: FIT Clinical Decision‐Making: Arrhythmias and Clinical Electrophysiology
Abstract Category: Prevention
Presentation Number: 1321M-11
Authors: Amit Arbune, Sharad Malavade, Timothy Edmiston, Zulfiqar Baloch, Saurabh Chokshi, MetroHealth Medical Center, Case
Western University, Cleveland, OH, USA, Brandon Regional Hospital, Brandon, FL, USA
Background: Tilt table test (TTT) is commonly used for dizziness work-up, that includes use of nitroglycerine(NTG) during provocation
phase. Paradoxical hypertensive reaction to NTG is extremely rare. Pheochromocytoma rarely presents as dizziness and hypertensive
emergency can rarely occur during TTT with NTG provocation in these patients.
Case: A 51year-old woman with controlled hypertension underwent TTT for dizziness with sublingual NTG for provocation phase. Within
1
4 minutes, she developed hypertensive emergency, pulmonary edema and cardio-pulmonary instability with room air SpO 71%, heart
2
rate 103 bpm and BP 273/158mmHg, cold, clammy and greyish skin. Possible anaphylaxis to NTG with hypertensive emergency was
suspected and treated with hydralazine, metoprolol, intravenous methylprednisolone sodium succinate and diphenhydramine. Initially,
epinephrine was withheld due to severe hypertension. Despite treatment, patient decompensated with further respiratory distress and
developed hypotension. Epinephrine was given with respiratory support to stabilize her. She recovered uneventfully and was discharged
home.
Decision‐Making: Possible anaphylaxis to NTG was suspected given the rapidity of the patient’s adverse reaction. Skin test with NTG
was recommended, but posed risk of life threatening adverse reaction. Hyperadrenergic surge from undiagnosed pheochromocytoma was
considered as alternate diagnosis. Laboratory studies showed elevated 24-hour urine metanephrine 4266 mcg/24hr (normal range, 140
to 785) and 24-hour urine normetanephrine 4175 mcg/24hr (normal range, 75 to 375). MRI of abdomen revealed right suprarenal mass
consistent with diagnosis of pheochromocytoma.
Conclusions: NTG, an antihypertensive, with paradoxical hypertensive response should evoke suspicion for pheochromocytoma. Focused
laboratory and imaging studies prevented a potentially life threatening skin test with nitroglycerine in this patient.