A Catalytic Version of the Knorr Pyrrole Synthesis Permits Access to Pyrroles and Pyridines
Journal of the American Chemical Society,
Год журнала:
2024,
Номер
146(46), С. 32098 - 32104
Опубликована: Ноя. 11, 2024
Aromatic
N-heterocycles,
such
as
pyrroles
and
pyridines,
are
important
natural
products
bulk
fine
chemicals
with
numerous
applications
active
ingredients
of
pharmaceuticals
agrochemicals,
catalysts,
in
materials
sciences.
We
report
here
a
catalytic
version
the
Knorr
pyrrole
synthesis
which
simple
diversely
available
starting
materials,
1,2-amino
alcohols
or
1,3-amino
keto
esters,
undergo
dehydrogenative
coupling
to
form
respectively.
Our
reaction
forms
hydrogen
collectible
(and
usable)
byproduct
is
mediated
by
well-defined
Mn
catalyst.
The
highly
functionalized
heterocycles
was
demonstrated,
35
compounds,
not
yet
reported
literature,
were
introduced.
Язык: Английский
Sustainable Hydrogen Production by Glycerol and Monosaccharides Catalytic Acceptorless Dehydrogenation (AD) in Homogeneous Phase
ChemSusChem,
Год журнала:
2024,
Номер
unknown
Опубликована: Ноя. 6, 2024
In
the
quest
for
sustainable
hydrogen
production,
use
of
biomass-derived
feedstock
is
gaining
importance.
Acceptorless
Dehydrogenation
(AD)
in
presence
efficient
and
selective
catalysts
has
been
explored
worldwide
as
a
suitable
method
to
produce
from
hydrogen-rich
simple
organic
molecules.
Among
these,
glycerol
sugars
have
advantage
being
inexpensive,
abundant,
obtainable
fatty
acid
basic
hydrolysis
(biodiesel
industry)
biomass
by
biochemical
thermochemical
processing,
respectively.
Although
heterogeneous
are
more
widely
used
production
biomass-based
feedstock,
harsh
reaction
conditions
often
limit
their
applicability
due
deactivation
active
sites
caused
coking
carbonaceous
materials.
Moreover,
difficult
fine-tune
than
homogeneous
counterparts,
latter
also
allow
high
process
selectivities
under
milder
conditions.
The
present
Concept
article
summarizes
main
features
most
reported
monosaccharides
AD.
order
directly
compare
efficiencies,
choice
literature
works
was
limited
reports
where
clearly
quantified
yields
turnover
numbers
(TONs).
types
transition
metals
ligands
discussed,
together
with
perspective
view
on
future
challenges
AD
reactions
practical
applications.
Язык: Английский
Depolymerization of Kraft Lignin Using a Metal Chloride-Based Deep Eutectic Solvent: Pathways to Sustainable Lignin Valorization
Applied Sciences,
Год журнала:
2024,
Номер
14(24), С. 11571 - 11571
Опубликована: Дек. 11, 2024
Driven
by
the
urgent
need
for
sustainable
alternatives
to
fossil
fuels,
focus
on
exploration
of
lignocellulosic
biomass,
particularly
lignin,
as
a
promising
renewable
feedstock
biofuels
and
high-value
chemicals
has
intensified.
This
study
investigated
depolymerization
KL
using
DES
comprising
ChCl
ZnCl2.
Our
analysis
systematically
focused
effects
reaction
temperature,
time,
DES-to-lignin
ratio
yields
characteristics
products.
Optimal
was
observed
at
temperature
190
°C
duration
8
h,
yielding
maximum
liquid
product
yield
54.44%
RL
45.56%.
The
results
revealed
that
increasing
enhanced
process
owing
reduction
in
viscosity
DES,
which
improved
mass
transfer
interactions
with
lignin.
Under
these
optimal
conditions,
molecular
weight
bio-oil
considerably
lower
(Mw
=
1498
g/mol
Mn
1061
g/mol)
than
obtained
without
treatment
1872
1259
g/mol),
indicating
more
favorable
distribution
treatment.
Furthermore,
elemental
O,
N,
S
contents
following
treatment,
high
heating
value
from
24.82
MJ
kg−1
non-DES-treated
26.44
DES-treated
RL.
These
findings
underscore
potential
(ChCl:ZnCl2)
effective
medium
lignin
valorization,
paving
way
synthesis
high-quality
biomass.
Язык: Английский