2 research outputs found
Rational Design and Facial Synthesis of Li<sub>3</sub>V<sub>2</sub>(PO<sub>4</sub>)<sub>3</sub>@C Nanocomposites Using Carbon with Different Dimensions for Ultrahigh-Rate Lithium-Ion Batteries
Li<sub>3</sub>V<sub>2</sub>(PO<sub>4</sub>)<sub>3</sub> (LVP) particles
dispersed in different inorganic carbons (LVP@C) have been successfully
synthesized via an in situ synthesis method. The inorganic carbon
materials with different dimensions including zero-dimensional Super
P (SP) nanospheres, one-dimensional carbon nanotubes (CNTs), two-dimensional
graphene nanosheets, and three-dimensional graphite particles. The
effects of carbon dimensions on the structure, morphology, and electrochemical
performance of LVP@C composites have been systematically investigated.
The carbon materials can maintain their original morphology even after
oxidation (by NH<sub>4</sub>VO<sub>3</sub>) and high-temperature sintering
(850 °C). LVP@CNT exhibits the best electrochemical performances
among all of the samples. At an ultrahigh discharge rate of 100C,
it presents a discharge capacity of 91.94 mAh g<sup>–1</sup> (69.13% of its theoretical capacity) and maintains 79.82% of its
original capacity even after 382 cycles. Its excellent electrochemical
performance makes LVP@CNT a promising cathode candidate for lithium-ion
batteries
The Manufacture of a Homochiral 4‑Silyloxycyclopentenone Intermediate for the Synthesis of Prostaglandin Analogues
A process is described for the synthesis of kilogram
quantities
of homochiral 4-silyloxycyclopentenone (<i>R</i>)-<b>1</b>, a key intermediate useful for the synthesis of a plurality
of prostaglandin analogue drugs. Cyclopentenone (<i>R</i>)-<b>1</b> was synthesized in 14 isolated steps from furfural.
Key steps in the synthesis include a Wittig reaction, Piancatelli
rearrangement, and an enzymatic resolution featuring in situ recycling
of the undesired enantiomer furnishing the desired homochiral alcohol
in ≥99.5% ee. As a retort to the unsatisfactory coformation
of about 8% at best of the <i>trans</i>-olefin in the Wittig
reaction, a change to the order of several steps and the identification
of a recrystallisable, amine salt derivative, <b>2</b>, allowed
the unwanted isomer to be controlled to as low as 0.2%