ﺳﻨﺘﺰ، ﺷﻨﺎﺳﺎﯾﯽ و ﮐﺎرﺑﺮد ﮐﻤﭙﻠﮑﺲ ﻧﯿﮑﻞ ﺗﺜﺒﯿﺖ ﺷﺪه ﺑﺮروي ﻧﺎﻧﻮ ﺣﻔﺮات -MCM 41 ﺑﻌﻨﻮان ﻧﺎﻧﻮﮐﺎﺗﺎﻟﯿﺰﮔﺮ ﻗﺎﺑﻞ ﺑﺎزﯾﺎﻓﺖ و ﻣﻮﺛﺮ ﺑﺮاي اﮐﺴﺎﯾﺶ ﺳﻮﻟﻔﯿﺪﻫﺎ و ﺗﯿﻮلﻫﺎ

Synthesis, Characterization and Catalytic application of Nickel Complex Functionalized on MCM-41 Nanostructure as an Efficient and Recoverable Nanocatalyst for Oxidation of Sulfides to Sulfoxides and Thiols to Disulfides

در اﯾﻦ ﭘﮋوﻫﺶ، ﮐﻤﭙﻠﮑﺲ ﺑﺎز-ﺷﯿﻒ ﻧﯿﮑﻞ ﻧﺸﺎﻧﺪه ﺷﺪه ﺑﺮ روي ﻧﺎﻧﻮ ﺣﻔﺮات 41-MCM ﺣﺎوي 4-ﻫﯿﺪروﮐﺴﯽ-3-ﻣﺘﻮﮐﺴﯽ ﺑﻨﺰآﻟﺪﻫﯿﺪ (واﻧﯿﻠﯿﻦ) ﺗﻬﯿﻪ و ﺑﺎ اﺳﺘﻔﺎده از روش ﻫﺎي ﻃﯿﻒ ﺳﻨﺠﯽ EDX ،ICP-OES ،SEM ،TGA ،XRD و FT-IR ﺷﻨﺎﺳﺎﯾﯽ ﺷﺪ. واﻧﯿﻠﯿﻦ ﮐﻪ ﺑﻪ ﺻﻮرت ﻃﺒﯿﻌﯽ در ﺗﺮﮐﯿﺒﺎت ﻏﺬاﯾﯽ و در ﮔﯿﺎه وﺟﻮد دارد، ﺑﻪ ﻋﻨﻮان ﻟﯿﮕﺎﻧﺪ ﺑﺎز ﺷﯿﻒ ﻗﺎﺑﻞ دﺳﺘﺮس، ارزان، ﻏﯿﺮ ﺳﻤﯽ ﮐﻪ ﻣﯽ ﺗﻮاﻧﺪ ﺑﺮروي 41-NH2-MCM ﻣﺘﺼﻞ ﺷﻮد، ﻣﻮرد اﺳﺘﻔﺎده ﻗﺮار ﮔﺮﻓﺖ. ﺗﻤﺎم داده ﻫﺎي آﻧﺎﻟﯿﺰي ﻧﺸﺎن از ﺗﺸﮑﯿﻞ ﮐﻤﭙﻠﮑﺲ ﺑﺎز-ﺷﯿﻒ واﻧﯿﻠﯿﻦ-ﻧﯿﮑﻞ را دارد. اﮐﺴﺎﯾﺶ اﻧﺘﺨﺎﺑﯽ ﺳﻮﻟﻔﯿﺪﻫﺎ ﺗﺤﺖ ﺷﺮاﯾﻂ ﺑﺪون ﺣﻼل و ﺟﻔﺖ ﺷﺪن اﮐﺴﺎﯾﺸﯽ ﺗﯿﻮلﻫﺎ در اﺗﺎﻧﻮل ﺑﺎ اﺳﺘﻔﺎده از ﻫﯿﺪروژن ﭘﺮاﮐﺴﯿﺪ(H2O) ﺑﻪ ﻋﻨﻮان اﮐﺴﯿﺪ ﮐﻨﻨﺪه ﺳﺒﺰ در ﺣﻀﻮر 41-Ni-Vanillin-MCM ﺑﻪ ﻋﻨﻮان ﮐﺎﺗﺎﻟﯿﺰﮔﺮ ﮐﺎرآﻣﺪ در دﻣﺎي اﺗﺎق ﺑﻪ ﻃﻮر ﻣﻮﻓﻘﯿﺖ آﻣﯿﺰي اﻧﺠﺎم ﮔﺮﻓﺖ. ﺳﯿﺴﺘﻢ ﮐﺎﺗﺎﻟﯿﺰﮔﺮي ﻃﺮاﺣﯽ ﺷﺪه ﺑﻪ ﻃﻮر ﻣﻮﺛﺮي از اﮐﺴﯿﺪاﺳﯿﻮن ﺑﯿﺶ از ﺣﺪ ﺳﻮﻟﻔﯿﺪ ﻫﺎ و ﺗﯿﻮلﻫﺎ ﺑﻪ ﺳﻮﻟﻔﻮن و ﺗﯿﻮﺳﻮﻟﻔﻮﻧﺎت ﺟﻠﻮﮔﯿﺮي ﻧﻤﻮده و وﯾﮋﮔﯽﻫﺎي ﻣﻔﯿﺪي را ﻣﺎﻧﻨﺪ ﺟﺪاﺳﺎزي آﺳﺎن، ﺷﺮاﯾﻂ ﻣﻼﯾﻢ اﻧﺠﺎم واﮐﻨﺶ، ﺑﺎزده ﺑﺎﻻ و ﮐﺎﺗﺎﻟﯿﺰﮔﺮ ارزان ﻗﯿﻤﺖ و ﻏﯿﺮ ﺳﻤﯽ را ﺷﺎﻣﻞ ﻣﯽ ﺷﻮد. ﻫﻤﭽﻨﯿﻦ، اﯾﻦ ﮐﺎﺗﺎﻟﯿﺰﮔﺮ ﻧﺎﻫﻤﮕﻦ ﺑﺴﯿﺎر ﻓﻌﺎل ﺑﻮده و ﻣﯽ-ﺗﻮاﻧﺪ ﺣﺪاﻗﻞ ﺑﺮاي 5 ﺑﺎر ﺑﻪ ﺳﺮﻋﺖ ﺑﺪون ﮐﺎﻫﺶ ﭼﺸﻤﮕﯿﺮي در ﻓﻌﺎﻟﯿﺖ ﮐﺎﺗﺎﻟﯿﺰﮔﺮي آن ﯾﺎ ﺷﺴﺘﻪ ﺷﺪن ﻓﻠﺰ، ﺑﺎزﯾﺎﻓﺖ ﺷﻮد

In this study a nickel-vanillin Schiff base complex has been synthesized via immobilization of nickel metal ion on mesoporous silica MCM-41 containing 4-hydroxy-3-methoxy benzaldehyde (vanillin) and characterized by XRD, TGA, SEM, ICP-OES, EDX and FT-IR spectroscopy. Vanillin which is naturally occurring food compounds found in plant was used as a Schiff base ligand is a readily available, inexpensive and non-toxic that can be anchored on NH2-MCM-41 and all the analysis data evinced the formation nickel-vanillin Schiff base complex. Selective oxidation of sulfides under solvent free conditions and oxidative coupling of thiols in ethanol were successfully performed by employing hydrogen peroxide (H2O2) as a green oxidant in the presence of Ni-Vanillin-MCM-41 as the efficient catalyst at room temperature. The designed catalytic system prevent effectively the over oxidation of sulfides and thiols to sulfone and thiosulfonate other beneficial features include, the simple work- up, mild reaction conditions, excellent yields, inexpensive and non-toxicity. Also this heterogeneous catalyst was a very active and could be readily recovered and reused at least for 5 consecutive cycles without a significant loss of its catalytic activity or metal leaching.