Catalytic reduction of p-nitrophenol by using platinum nanoparticles stabilised by guar gum
Sadanand Pandey1, Shivani B Mishra1
1Department of Applied Chemistry, University of Johannesburg, 37 Nind Street, Doornfontein, Johannesburg 2028, South Africa.
Abstract:
We report a facile and green method to synthesise highly stable dispersions of platinum nanoparticles (PtNPs) with an average particle size of ∼ 6 nm. Natural, nontoxic, eco-friendly biopolymer guar gum was utilised as both the reducing and capping agent precursor in aqueous medium. The PtNPs that had been stabilised by guar gum (GG-s-PtNPs) were characterised by UV-vis spectroscopy, XRD, TEM and XPS. GG-s-PtNPs performed better in terms of catalytic activity for the liquid phase reduction of p-nitrophenol (p-NP) compared to p-aminophenol (p-AP). The efficiency of the catalytic reduction of p-NP over GG-s-PtNPs was found to be 97% in a total time of 320 s at room temperature. The mechanisms of the synthesis and catalytic reduction of p-NP are also discussed. The synthesis approach presented here does not require stringent conditions or toxic agents and thus is a straightforward, rapid, efficient, and green approach to the fabrication of highly active catalysts.
Related Concept Videos
02:17Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
01:29Preparation of Amines: Reduction of Oximes and Nitro Compounds
Though catalytic hydrogenation can reduce nitrobenzenes, the reduction is nonselective in the presence of other functional groups. For instance, if nitrobenzene contains an aldehyde group,...
02:24Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
02:13Reduction of Alkenes: Catalytic Hydrogenation
Metals like palladium, platinum, and nickel are commonly used in their solid forms — fine powder on an inert surface. As these catalysts remain insoluble in the reaction mixture, they are referred to as heterogeneous catalysts.
The hydrogenation process takes place on the...
00:55Nitriles to Amines: LiAlH4 Reduction
As shown below, the mechanism involves three steps. Firstly, the hydride ion acting as a nucleophile attacks the nitrile carbon to form an anion. In the second step, a second equivalent of the hydride ion attacks the anion to...
02:23Alcohols from Carbonyl Compounds: Reduction
Catalytic hydrogenation is similar to the reduction of an alkene or alkyne by adding H2 across the pi bond in the presence of transition metal catalysts like Raney Ni, Pd–C, Pt, or Ru. Aldehydes and ketones can be reduced by this method, often under mild to moderate heat...