In this study, the dissociative adsorption of NaNO2, NaNO3, HNO2, HNO3 and H2SO4 over (1 1 0) surface of γ-alumina non-spinel model were investigated through the dispersion corrected density functional theory (DFT-D) at PBE-D/DNP level of calculation. It was found that all of the species are dissociated to their ionic forms after adsorption and relaxation over the surface, i.e. Na+NO2−, Na+NO3−, H+NO2−, H+NO3−, H+HSO4− and 2H+SO42−. The Lewis acidity of alumina surface by addition of HNO2, HNO3 and H2SO4 is increased, while in the presence of NaNO2 and NaNO3, the acidity of catalyst is decreased. Theoretical calculations predict stronger dissociative adsorption of H2SO4 over the surface in compared to other compounds. The HNO2 and HNO3 mineral acids are better adsorbed over the surface than NaNO2 and NaNO3 salts. The better adsorption of nitrites than nitrates is due to the stronger electrostatic attractions. The order of NaNO3 < NaNO2 < HNO3 < HNO2 < H2SO4 for the dissociative adsorption energy of the title compounds is predicted. پرونده مقاله

The influence of NaNO2, HNO3 and H2SO4 on the structure and morphology of gamma-alumina was investigated by XRD, BET, SEM and FT-IR spectroscopy. Selected amounts of NaNO2, HNO3 and H2SO4 were added to a solution of aluminum isopropoxide (as a precursor for the boehmite synthesis). The boehmite samples were calcined at 350 and 600 ℃ to form the semi-crystalline high surface area gamma-Al2O3. The reactivity and selectivity of the modified gamma-alumina catalysts were examined using dehydration reaction of 2-octanol. There was a good correlation between reactivity, selectivity and the amounts (and type) of the modification. The dominant product was cis-2-octene for all of the catalysts. Low conversion and high selectivity were obtained for dehydration of 2-octanol over alumina modified with NaNO2. High conversion, low selectivity and excessive isomerization were found for gamma-alumina catalyst modified with H2SO4. پرونده مقاله

In this study, the nanoporous γ-alumina catalysts were prepared by the sol-gel method using hydrolysis of aluminum isopropoxide in the presence of TX-100 or gelatin/TX-100 mixture. Catalysts were characterized by XRD, FT-IR, TEM, BET-BJH and N2 adsorption-desorption isotherms. To investigate reactivity and selectivity of the synthesized catalysts, dehydration reaction of 2-octanol was carried out in a plug flow vertical reactor at 200 °C. The main products of elimination reaction were 1-octene, 3-octene, cis- and trans-2-octene, which were identified by GC-MS. The reaction conversion and yieldof the products were determined using GC. The prepared catalysts had nanometer-sized pores, high surface area and large pore volume. Their catalytic activity for dehydration of 2-octanol was higher than non-porous γ-alumina catalysts. These compounds could be used as effective catalysts for dehydration of alcohols. پرونده مقاله

در این مقاله، نانوذرات γ-آلومینای آغشته به جیوه با روش آغشته‌سازی نانوذرات γ-آلومینا با جیوه استات در محلول آب و ایزوپروپانول و به دنبال آن آبکافت، شستشو، صاف و خشک‌کردن در دمای اتاق، تهیه شدند. ساختار این نانوذرات با الگوی پراش پرتو ایکس (XRD) تأیید شد. از الگوی XRD برای تأیید پیوند بین نانوذرات آغشته به جیوه و باز آلی تیمین در DNA سلول هدف نیز استفاده شد. اثرات زیستی و سمی نانوذرات γ-آلومینا و γ-آلومینای آغشته به جیوه بر سلول‌های سرطانی هلا (Hella) و سلول‌های بنیادی مغز استخوان با آزمون MTT بررسی شد. برپایه نتایج به‌دست آمده، سمی‌بودن نانوذرات γ-آلومینای آغشته به جیوه بر سلول‌های سرطانی هلا بیشتر از سلول‌های بنیادی بود. به عبارت دیگر، نانوذرات γ-آلومینای آغشته به جیوه تأثیر قابل‌توجهی در از بین بردن سلول‌های سرطانی هلا داشتند. همچنین، مشخص شد نانوذرات γ-آلومینای خالص در غلطت‌های پایین نسبت به آلومینای آغشته به جیوه کمتر سمی هستند. پرونده مقاله