3 research outputs found
Design, Polymerization, and Properties of High-Performance Seed-Oil-Derived Lubricants
There is a significant amount of interest and research
in seed-oil-derived
lubricants because of elevated environmental consciousness among producers
and consumers. While slowly making inroads into selected applications,
performance deficits at low temperature and poor thermooxidative stability
have consistently relegated seed oil derivatives to roles where biodegradability
is paramount or where the performance requirements are relatively
low. In this article, the structural attributes that result in seed-oil-derived
lubricant properties are defined and quantified. Also, the seed oil
triglyceride components are segregated, functionalized, and polymerized
to provide a lubricant design that allows flexibility in defining
the specified viscosity, while providing an improved low-temperature
performance and removing the source of thermooxidative instability
Coupling Charge Reduction Mass Spectrometry to Liquid Chromatography for Complex Mixture Analysis
Electrospray
ionization (ESI) of solution mixtures often generates
complex mass spectra, even following liquid chromatography (LC), due
to analyte multiple charging. Multiple charge state distributions
can lead to isobaric interferences, mass spectral congestion, and
ambiguous ion identification. As a consequence, data interpretation
increases in complexity. Several charge reduction mass spectrometry
(MS) approaches have been previously developed to reduce the average
charge state of gaseous ions; however, all of these techniques have
been restricted to direct infusion MS. In this study, synthetic polyols
and surfactants separated by liquid chromatography and ionized by
positive mode ESI have been subjected to polonium-210 α-particle
radiation to reduce the average charge state to singly charged cations
prior to mass analysis. LC/MS analysis of 5000 molecular weight polyÂ(ethylene
glycol) (PEG5000) generated an average charge state of 5.88+; whereupon,
liquid chromatography/electrospray ionization/charge reduction/mass
spectrometry (LC/CR/MS) analysis of PEG 5000 generated an average
charge state of 1.00+. The PEG5000 results demonstrated a decrease
in spectral complexity and enabled facile interpretation. Other complex
solution mixtures representing specific MS challenges (i.e., competitive
ionization and isobaric ion overlap) were explored and analyzed with
LC/CR/MS to demonstrate the benefits of coupling LC to CR/MS. For
example, polyol information related to initiator, identity/relative
amount of monomer, and estimated molecular weight was characterized
in random and triblock ethylene oxide/propylene oxide polyols using
LC/CR/MS. LC/CR/MS is a new analytical technique for the analysis
of complex mixtures
Developing Efficient Nucleophilic Fluorination Methods and Application to Substituted Picolinate Esters
This
report describes nucleophilic fluorination of 3 and 5-substituted
picolinate ester substrates using potassium fluoride in combination
with additive promoters. Agents such as tributylmethylammonium or
tetraphenylphosphonium chloride were among the best additives investigated
giving improved fluorination yields. Additionally, the choice of additive
promoters could influence the potential formation of new impurities
such as alkyl ester exchange. Other parameters explored in this study
include additive stoichiometry, temperature influence on additive
degradation, solvent selection, product isolation by solvent extraction,
and demonstration of additive recycling