Optimization of Starting Material Composition in the Synthesis of Highly Active Magnesium Ethoxide‐Supported Ziegler–Natta Catalysts for Propylene Polymerization
Journal of Polymer Science,
Год журнала:
2025,
Номер
unknown
Опубликована: Фев. 6, 2025
ABSTRACT
We
aim
to
deepen
our
understanding
of
the
structure‐performance
relationship
in
Ziegler–Natta
catalysts
(ZNCs)
for
propylene
polymerization.
To
this
end,
three
different
Mg(OEt)₂
supports
were
synthesized
by
reacting
magnesium
powder
with
varying
amounts
MnCl₂
during
magnesium‐ethanol
reaction
stage.
Despite
similar
XRD
patterns
among
all
obtained
Mg(OEt)
2
samples,
at
an
optimal
MnCl
/Mg
ratio
g/g,
well‐spherically
shaped
particles
plate‐like
building
units
formed.
The
prepared
support
precursors
then
used
ZNC
synthesis
TiCl₄/Mg(OEt)₂
ratios
and
internal
donor
types,
their
behavior
polymerization
was
thoroughly
explored.
overall
results
indicated
that
Ti/Mg
is
8
mol/mol.
Additionally,
phthalate
as
demonstrated
higher
activity
compared
diethyl
ether
or
succinate‐based
donors.
kinetic
curve
uptake
versus
time
experiments
external
content
mathematically
modeled
evaluate
changes
rate
constants.
calculated
constants
showed
increases,
k
trH
,
d
iED
tED
enhance,
while
p
decreases
significantly
due
poisoning
active
sites
donor.
These
findings
highlight
critical
role
type
amount
catalyst
components
achieving
performance.
Язык: Английский
Looking into the Quest for Stereoselective Ring-Opening Polymerization of Racemic Lactide with Chiral Organocatalysts
ACS Catalysis,
Год журнала:
2025,
Номер
unknown, С. 4141 - 4146
Опубликована: Фев. 22, 2025
Язык: Английский
Stereoselectivity Control Interplay in Racemic Lactide Polymerization by Achiral Al‐Salen Complexes
Macromolecular Rapid Communications,
Год журнала:
2024,
Номер
unknown
Опубликована: Окт. 22, 2024
Abstract
The
origin
of
stereocontrol
in
ring
opening
polymerization
(ROP)
racemic
lactide
(
rac
‐LA)
promoted
by
achiral
aluminium‐based
catalysts
has
been
explained
through
DFT
calculations
combined
with
a
molecular
descriptor
(%
V
Bur
)
and
the
activation
strain
model
(ASM‐NEDA)
analysis.
proposed
chain
end
control
(CEC)
suggests
that
ligand
framework
adopts
chiral
configuration
mimicking
enantiomorphic
site
(ESC)
while
also
incorporating
last
inserted
monomer
unit.
It
is
found
wrapping
mode
around
aluminium
centre
dictated
R
,
‐LA
S
‐LA).
A
good
correlation
experimental
data
achieved
only
when
accounting
for
dynamic
features
its
steric
influences,
as
highlighted
%
maps
ASM‐NEDA
Understanding
ESC
CEC
interplay
an
important
target
obtaining
stereoselective
ROP
synthesis
biodegradable
materials
tailored
properties.
Язык: Английский
Synthesis of Aluminum Complexes Based on 2,6‐Bis(2‐hydroxyphenyl)Pyridines: Efficient Initiators for Ring‐Opening Polymerization of Cyclic Esters
ChemistrySelect,
Год журнала:
2024,
Номер
9(45)
Опубликована: Дек. 1, 2024
Abstract
The
search
for
new
initiators
based
on
nontoxic
metal
complexes,
allowing
the
controlled
production
of
polycaprolactone
(PCL)
and
polylactide
(PLA)
is
an
actual
task.
In
present
work,
we
report
synthesis
aluminum
complexes
6a
6b
substituted
2,6‐bis(2‐hydroxyphenyl)pyridine
pro‐ligands.
compositions
structures
novel
compounds
were
established
by
elemental
analysis
1
H,
13
C,
NMR
spectroscopy
in
solid
state
X‐ray
diffraction
(
).
All
synthesized
are
monomeric.
Complexes
(in
presence
benzyl
alcohol
(BnOH))
turned
out
to
be
active
ring
opening
polymerization
(ROP)
ε
‐caprolactone
‐CL),
L‐,
rac‐
lactide
(L‐,
rac
‐LA)
gave
PCL
PLA
with
high
molecular
weights.
mechanism
reaction
С
,
6a,
was
also
investigated
using
density
functional
theory
(DFT)
method.
substituent
effect
analyzed
terms
percent
buried
volume
non‐covalent
interactions.
values
calculated
Gibbs
free
activation
energies
correspond
trend
found
experimentally.
Язык: Английский