The
bituminous crudes derived from tar sands as well as heavy crude oils
are characterized by high viscosity, which poses problems during their
pipeline transportation. These oils contain a significantly higher
percentage of asphaltenes, which have polycondensed aromatic ring
structures and tend to self-aggregate to produce a viscoelastic structure
resulting in the high viscosity. Apart from blending and dilution
to reduce viscosity, a method being explored is the addition of chemicals
in small amounts that can hinder or alter the aggregation in such
a way that the viscosity is reduced. In the present work, two novel
gemini surfactants were synthesized in the laboratory by the reaction
between 4-(dimethylamino) benzaldehyde and 1-bromododecane, which
formed an intermediate compound in the first step. This intermediate
compound was treated with 6-methyl-1,3,5-triazine-2,4-diamine to obtain
the gemini surfactant N,N′-bis{(p-(N,N,N-dodecyldimethylammonium
chloride) benzylidene} 6-methyl-1,3,5-triazine-2,4-diamine, denoted
as VRA-1 and separately with 6-phenyl-1,3,5-triazine-2,4-diamine
to obtain N,N′-bis{(p-(N,N,N-dodecyldimethylammonium chloride)benzylidene}
6-phenyl-1,3,5-triazine-2,4-diamine, denoted as VRA-2. After confirming the structures of these synthesized products by
elemental analysis (CHN), infrared (IR) spectroscopy, and nuclear
magnetic resonance (NMR) spectroscopy, these were investigated for
their viscosity reducing properties. Studies were carried out for
their application as viscosity reducing agents (VRAs)
in the bituminous crude obtained from high grade Canadian oil sands.
This bituminuous crude was blended with toluene followed by doping
of these surfactants in the dosage varying from 100 to 600 ppm. The
rheological behavior of these was determined at temperatures of 20,
40, and 60 °C at variable shear rates. The studies indicated
that these types of compounds can be effective as viscosity reducing
agents for heavy crude oils. In the present case, VRA-2 has shown better performance as compared to VRA-1.