Synthesis of Porous Manganese Oxides with Unsaturated Alcohols and Subsequent Characterization and Catalytic Activity
Porous manganese oxides have been synthesized using unsaturated alcohols (allyl alcohol and propargyl alcohol) as reducing agents in a redox reaction with KMnO4 in the presence of butyric acid. Materials have an approximate MnO2 stoichiometry and surface areas of 280 m2/g for materials made with allyl alcohol and 260 m2/g for those made with propargyl alcohol. Materials also showed a good deal of monodispersity, with the materials made from allyl alcohol having an average diameter of 156 nm± 61 nm. The materials made with propargyl alcohol had an average diameter of 143 nm ±49 nm.
Previously, highly monodisperse porous spheres were synthesized using butanol as the reducing agent in a redox reaction with KMnO4 in the presence of butyric acid. It was hypothesized that since allyl alcohol and propargyl alcohol have a similar polarity to butanol, similar monodisperse, porous spheres would form. However, due to the presence of multiple reactive sites, materials made with the unsaturated alcohols would be formed quicker, have a smaller particle size, and have higher surface areas when compared to those made with butanol. This thesis reports on these findings and the confirmation of our hypothesis.
These materials have also proven to be active catalysts in the conversion of isopropyl alcohol to acetone. Conversions percentages were about 90% for the materials made with ally alcohol at 200°C and about 94% for materials made with either propargyl alcohol or allyl alcohol at 250°C.
Lastly, doping of these materials with metal cations followed by heat treatment, calcination or hydrothermal, led to formation of several crystalline structures such as spinel, birnessite, and cryptomelane, among others.
De La Cruz, Chrismary, "Synthesis of Porous Manganese Oxides with Unsaturated Alcohols and Subsequent Characterization and Catalytic Activity" (2016). Chemistry Honors Papers. 17.
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