Aqueous Dispersions of Silica Stabilized with Oleic Acid Obtained by Green Chemistry.
The present study describes for the first time the synthesis of silica nanoparticles starting from sodium silicate and oleic acid (OLA). The interactions between OLA and sodium silicate require an optimal OLA/OLANa molar ratio able to generate vesicles that can stabilize silica particles obtained by the sol-gel process of sodium silicate. The optimal molar ratio of OLA/OLANa can be ensured by a proper selection of OLA and respectively of sodium silicate concentration. The titration of sodium silicate with OLA revealed a stabilization phenomenon of silica/OLA vesicles and the dependence between their average size and reagent's molar ratio. Dynamic light scattering (DLS) and scanning electron microscopy (SEM) measurements emphasized the successful synthesis of silica nanoparticles starting from renewable materials, in mild condition of green chemistry. By grafting octadecyltrimethoxysilane on the initial silica particles, an increased interaction between silica particles and the OLA/OLANa complex was achieved. This interaction between the oleyl and octadecyl chains resulted in the formation of stable gel-like aqueous systems. Subsequently, olive oil and an oleophylic red dye were solubilized in these stable aqueous systems. This great dispersing capacity of oleosoluble compounds opens new perspectives for future green chemistry applications. After the removal of water and of the organic chains by thermal treatment, mesoporous silica was obtained.
R & D National Institute for Chemistry and Petrochemistry, Spl. Independentei 202, 6th District, 060021 Bucharest, Romania. lc_nistor@yahoo.com.
Cristina Lavinia
CL
Nistor
R & D National Institute for Chemistry and Petrochemistry, Spl. Independentei 202, 6th District, 060021 Bucharest, Romania. ralumoc@yahoo.com.
Raluca
R
Ianchis
R & D National Institute for Chemistry and Petrochemistry, Spl. Independentei 202, 6th District, 060021 Bucharest, Romania. ghiurea@yahoo.com.
Marius
M
Ghiurea
R & D National Institute for Chemistry and Petrochemistry, Spl. Independentei 202, 6th District, 060021 Bucharest, Romania. ca_nicolae@yahoo.com.
Cristian-Andi
CA
Nicolae
R & D National Institute for Chemistry and Petrochemistry, Spl. Independentei 202, 6th District, 060021 Bucharest, Romania. catalin_spataru2004@yahoo.com.
Catalin-Ilie
CI
Spataru
"Ilie Murgulescu" Institute of Physical Chemistry of Romania Academy, Spl. Independentei 202, 6th District, 060021 Bucharest, Romania. dculita@icf.ro.
Daniela Cristina
DC
Culita
"Ilie Murgulescu" Institute of Physical Chemistry of Romania Academy, Spl. Independentei 202, 6th District, 060021 Bucharest, Romania. jeaninamirea@yahoo.com.
Jeanina
J
Pandele Cusu
"Ilie Murgulescu" Institute of Physical Chemistry of Romania Academy, Spl. Independentei 202, 6th District, 060021 Bucharest, Romania. vfruth@icf.ro.
Victor
V
Fruth
R & D National Institute for Chemistry and Petrochemistry, Spl. Independentei 202, 6th District, 060021 Bucharest, Romania. florino@ping.ro.
Florin
F
Oancea
R & D National Institute for Chemistry and Petrochemistry, Spl. Independentei 202, 6th District, 060021 Bucharest, Romania. ddonescu@chimfiz.icf.ro.
Dan
D
Donescu
hydrophobic; nanosilica; octadecyltrimethoxysilane; oleic acid; sodium silicate