Interaction between dipeptide (glycyl-phenylalanine) and ninhydrin: role of CTAB and gemini (16-s-16, s=4, 5, 6) surfactant micelles.
The kinetics of interaction of dipeptide glycylphenylalanine (Gly-Phe) with ninhydrin have been studied by following the reaction spectrophotometrically at 70 °C and a particular pH 5.0 in the absence and presence of conventional cetyltrimethylammonium bromide (CTAB) and gemini (alkanediyl-α,ω-bis(dimethylhexadecylammonium bromide)) surfactants. The rate shows first- and fractional-order dependence on [Gly-Phe] and [ninhydrin], respectively. The surfactants were found to catalyse the reaction. Furthermore, whereas the typical rate constant (kΨ) increase and leveling-off regions are observed with geminis, just like as seen with conventional surfactants, the former produced a third region of increasing kΨ at higher concentrations. A kinetic rate law consistent with experimental results has been derived on the basis of the proposed mechanism.
Department of Chemistry, Aligarh Muslim University, Aligarh 202002, India. Electronic address: dileepkmr271@gmail.com.
Dileep
D
Kumar
Chemistry Department, King Abdulaziz University, Jeddah 21589, Saudi Arabia; Center of Excellence for Advanced Materials Research, King Abdulaziz University, Jeddah 21589, Saudi Arabia.
Malik Abdul
MA
Rub
Department of Chemistry, Aligarh Muslim University, Aligarh 202002, India.
Mohd
M
Akram
Department of Chemistry, Aligarh Muslim University, Aligarh 202002, India.
Kabir-ud-Din
D002384:Catalysis; D000077286:Cetrimonium; D002593:Cetrimonium Compounds / Q000737:chemistry*; D004151:Dipeptides / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008823:Micelles; D009555:Ninhydrin / Q000737:chemistry*; D012996:Solutions; D013053:Spectrophotometry; D013501:Surface-Active Agents / Q000737:chemistry*; D013816:Thermodynamics
D002593:Cetrimonium Compounds; D004151:Dipeptides; D008823:Micelles; D012996:Solutions; D013501:Surface-Active Agents; C029660:glycylphenylalanine; D009555:Ninhydrin; D000077286:Cetrimonium
CTAB; Catalysis; Geminis; Gly-Phe; Ninhydrin