Angewandte Chemie,
Journal Year:
2023,
Volume and Issue:
136(11)
Published: Dec. 18, 2023
Abstract
Catalytic
hydrogenolysis
has
the
potential
to
convert
high‐density
polyethylene
(HDPE),
which
comprises
about
30
%
of
plastic
waste,
into
valuable
alkanes.
Most
investigations
have
focused
on
increasing
activity
for
lab
grade
HDPEs
displaying
low
molecular
weight,
with
limited
mechanistic
understanding
product
distribution.
No
efficient
catalyst
is
available
consumer
grades
due
their
lower
reactivity.
This
study
targets
HDPE
used
in
bottle
caps,
a
waste
form
generated
globally
at
rate
approximately
one
million
units
per
hour.
Ultrafine
ruthenium
particles
(1
nm)
supported
titania
(anatase)
achieved
up
80
conversion
light
alkanes
(C
1
−C
45
)
under
mild
conditions
(498
K,
20
bar
H
2
,
4
h)
and
were
reused
three
cycles.
Small
nanoparticles
critical
achieving
relevant
conversions,
as
sharply
decreased
particle
size.
Selectivity
commonalities
peculiarities
across
disclosed
by
reaction
modelling
approach
applied
products.
Isomerization
cedes
backbone
scission
progresses.
Within
this
trend,
weight
favor
isomerization
whilst
high
cleavage.
Commercial
caps
obeyed
trend
activity,
anticipating
influence
additives
realistic
processing.
demonstrates
effective
provides
selectivity
patterns
control.
Chemical Reviews,
Journal Year:
2024,
Volume and Issue:
124(16), P. 9457 - 9579
Published: Aug. 16, 2024
The
large
production
volumes
of
commodity
polyolefins
(specifically,
polyethylene,
polypropylene,
polystyrene,
and
poly(vinyl
chloride)),
in
conjunction
with
their
low
unit
values
multitude
short-term
uses,
have
resulted
a
significant
pressing
waste
management
challenge.
Only
small
fraction
these
is
currently
mechanically
recycled,
the
rest
being
incinerated,
accumulating
landfills,
or
leaking
into
natural
environment.
Since
are
energy-rich
materials,
there
considerable
interest
recouping
some
chemical
value
while
simultaneously
motivating
more
responsible
end-of-life
management.
An
emerging
strategy
catalytic
depolymerization,
which
portion
C-C
bonds
polyolefin
backbone
broken
assistance
catalyst
and,
cases,
additional
molecule
reagents.
When
products
molecules
materials
higher
own
right,
as
feedstocks,
process
called
upcycling.
This
review
summarizes
recent
progress
for
four
major
upcycling
strategies:
hydrogenolysis,
(hydro)cracking,
tandem
processes
involving
metathesis,
selective
oxidation.
Key
considerations
include
macromolecular
reaction
mechanisms
relative
to
mechanisms,
design
transformations,
effect
conditions
on
product
selectivity.
Metrics
describing
critically
evaluated,
an
outlook
future
advances
described.
Energy & Fuels,
Journal Year:
2024,
Volume and Issue:
38(3), P. 1676 - 1691
Published: Jan. 22, 2024
Mechanical
recycling
of
plastic
waste
is
not
sustainable
and
inefficient
in
terms
the
resources
needed
to
accomplish
process,
quality
materials
obtained
from
this
technique
substandard.
Chemical
polymers
appears
be
preferable
because
technology
allows
for
production
new
materials.
This
review
compiles
most
recent
research
which
selected
transition
metals
are
used
as
catalysts
hydrogenolytic
depolymerization
polyolefins
a
polymer
upcycling
process.
Hydrogenolysis
an
emerging
chemical
method
that
uses
transition-metal
complexes
presence
hydrogen
cleave
C–C
bonds
substances
into
shorter
hydrocarbons.
Transition
such
Ruthenium
(Ru),
Platinum
(Pt),
Nickel
(Ni),
Cobalt
(Co),
Zirconium
(Zr),
Tantalum
(Ta),
Rhodium
(Rh)
have
been
utilized
recently
type
reaction.
hydrogenolysis
can
produce
valuable
hydrocarbon
products,
gas/liquid
fuels
lubricating
oils,
under
relatively
milder
operational
conditions
with
less
environmental
impact.
The
focused
on
supported
metal
organometal
catalytic
system
their
mechanism
polyolefin
pathways
detailed
investigation
impact
reaction
parameters
high
gasoline,
diesel,
light
lubricants.
ChemSusChem,
Journal Year:
2024,
Volume and Issue:
17(12)
Published: Jan. 31, 2024
Lignin,
the
most
prevalent
natural
source
of
polyphenols
on
Earth,
offers
substantial
possibilities
for
conversion
into
aromatic
compounds,
which
is
critical
attaining
sustainability
and
carbon
neutrality.
The
hydrogen-transfer
method
has
garnered
significant
interest
owing
to
its
environmental
compatibility
economic
viability.
efficacy
this
approach
contingent
upon
careful
selection
catalytic
hydrogen-donating
systems
that
decisively
affect
yield
selectivity
monomeric
products
resulting
from
lignin
degradation.
This
paper
highlights
technique
in
refinery,
with
a
specific
focus
influence
hydrogen
donors
depolymerization
pathways
lignin.
It
delineates
correlation
between
structure
activity
arrangements
gamut
lignin-derived
biochemicals,
utilizing
data
model
separated
lignin,
lignocellulosic
biomass.
Additionally,
delves
advantages
future
directions
employing
conversion.
In
essence,
concept
investigation
illuminates
paradigm
valorization,
offering
key
insights
strategic
directives
maximize
lignin's
value
sustainably.
Nature Chemical Engineering,
Journal Year:
2024,
Volume and Issue:
1(9), P. 565 - 575
Published: Aug. 28, 2024
Abstract
Since
the
dawn
of
agitated
brewing
in
Paleolithic
era,
effective
mixing
has
enabled
efficient
reactions.
Emerging
catalytic
chemical
polyolefin
recycling
processes
present
unique
challenges,
considering
that
polymer
melt
a
viscosity
three
orders
magnitude
higher
than
honey.
The
lack
protocols
to
achieve
may
have
resulted
suboptimal
catalyst
effectiveness.
In
this
study,
we
tackled
hydrogenolysis
commercial-grade
high-density
polyethylene
and
polypropylene
show
how
different
stirring
strategies
can
create
differences
up
85%
40%
effectiveness
selectivity,
respectively.
reaction
develops
near
H
2
–melt
interface,
with
extension
interface
access
particles
main
performance
drivers.
Leveraging
computational
fluid
dynamics
simulations,
identified
power
number
15,000–40,000
maximize
factor
optimize
parameters.
This
temperature-
pressure-independent
model
holds
across
range
1–1,000
Pa
s.
Temperature
gradients
quickly
become
relevant
for
reactor
scale-up.
Angewandte Chemie International Edition,
Journal Year:
2023,
Volume and Issue:
63(11)
Published: Dec. 18, 2023
Catalytic
hydrogenolysis
has
the
potential
to
convert
high-density
polyethylene
(HDPE),
which
comprises
about
30
%
of
plastic
waste,
into
valuable
alkanes.
Most
investigations
have
focused
on
increasing
activity
for
lab
grade
HDPEs
displaying
low
molecular
weight,
with
limited
mechanistic
understanding
product
distribution.
No
efficient
catalyst
is
available
consumer
grades
due
their
lower
reactivity.
This
study
targets
HDPE
used
in
bottle
caps,
a
waste
form
generated
globally
at
rate
approximately
one
million
units
per
hour.
Ultrafine
ruthenium
particles
(1
nm)
supported
titania
(anatase)
achieved
up
80
conversion
light
alkanes
(C
