We
examined the chemical composition and properties of several
diesel fuels and blendstocks derived from Fischer–Tropsch (FT)
synthesis, hydroisomerization of lipids, and fermentation of sugar
via the terpenoid metabolic pathway. Comprehensive two-dimensional
gas chromatographic analysis with nonpolar and polar columns, 13C NMR, GC-MS, and elemental analysis were used to assess
fuel chemistry. Performance properties included density, heat of combustion,
cetane number, and cloud point, as well as other properties. The fuels
consisted almost entirely of normal and iso-paraffins. Three samples
contained residual oxygen below 0.1 mass %. All of the renewable and
synthetic diesel fuels have significantly lower density than is typical
for a petroleum-derived diesel fuel. As a result, they have slightly
higher net heat of combustion on a mass basis (2%–3% higher),
but lower heat of combustion on a volume basis (3%–7% lower).
Two critical diesel performance properties, cetane number and cloud
point, were correlated with iso-paraffin content and chain length.
The results confirm that properties of hydroisomerized fats and oils,
as well as FT diesel, can be tuned by increasing the degree of isomerization
to lower cloud point which also lowers the cetane number. In spite
of this trade-off between cloud point, and cetane number, the cetane
numbers were still over 70 for fuels with cloud points as low as −27
°C. The terpenoid biofuel exhibited a cloud point below −70
°C and a cetane number of 58.
In this paper, we report the synthesis of a phenanthroline and neomycin conjugate (7). Compound 7 binds to a human telomeric G‐quadruplex (G1) with a higher affinity compared with its parent compounds (phenanthroline and neomycin), which is determined by several biophysical studies. Compound 7 shows good selectivity for G‐quadruplex (G4) DNA over duplex DNA. The binding of 7 with G1 is predominantly enthalpy‐driven, and the binding stoichiometry of 7 with G1 is one for the tight‐binding event as determined by ESI mass spectrometry. A plausible binding mode is a synergistic effect of end‐stacking and groove interactions, as indicated by docking studies. Compound 7 can inhibit human telomerase activity at low micromolar concentrations, which is more potent than previously reported 5‐substituted phenanthroline derivatives.
Statistical
analysis of electrospray ionization (ESI) high-resolution
accurate-mass (HRMS) liquid chromatography/mass spectrometry (LC/MS)
data offers a method to study the molecular origin of jet fuel thermal
oxidative stability issues as measured by ASTM D3241 (Standard Test
Method for Thermal Oxidation Stability of Aviation Turbine Fuels).
It is important to understand this type of data processing and how
to appropriately use it as a data analysis technique. In this work,
Mass Profiler Professional (MPP, Agilent) is used to analyze ESI HRMS
LC/MS data of jet fuels. The data are combined with ASTM D3241 results
for the jet fuels studied, offering insight into the identities of
molecules that correlate with poor results. These data offer support
for the soluble macromolecular oxidatively reactive species (SMORS)
model for distillate fuel instability.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.