The Catalyst Review July 2024 - 5

Process News
Pioneering Aromatic Generation from
Plastic Waste via Catalytic Thermolysis: A
Minireview
Pyrolysis is a significant method for mitigating the challenges
of plastic waste buildup and fossil energy resource depletion
since it converts plastic waste into value-added chemicals.
As a result, this comprehensive review examines the
pyrolysis mechanisms and product distributions of common
plastics such as polystyrene, polyethylene, poly(ethylene
terephthalate), polypropylene, and poly(vinyl chloride), as
well as their blends, and analyzes their inherent properties.
This study focuses particularly on recent advances in
catalytic pyrolysis, specifically the conversion of plastic
waste into aromatic compounds. Extensive explanations of
the complex relationships between the resultant products
and different reaction circumstances, such as reactor
type, catalyst, and reaction temperature, are presented.
Additionally, mechanistic and kinetic research are carefully
assessed. Lastly, a summary of the difficulties and future
directions in the catalytic pyrolysis of plastic waste is
presented. This evaluation provides information that may be
used as a guide for the creation of plastic recycling systems
and pyrolysis catalysts with industrial applicability.
Source: ACS, 6/13/2024.
Unraveling the Mechanism of Ethane
Oxidative Dehydrogenation and the
Important Role of CO2
A New Catalyst Can " Recycle " Carbon
Dioxide into Useful Chemicals
Scientists from the Argonne National Laboratory and the
University of Chicago have created a group of tin-based
catalysts that can effectively convert CO₂ into ethanol, acetic
acid, or formic acid, the most widely used chemicals in
commercial products in the US. Therefore, CO₂ produced
from fossil fuel power plants and waste treatment facilities
could be fully converted into chemicals by electrocatalytic
conversion. By varying the size of tin, scientists were able to
control the CO₂ conversion, changing the reaction path to
create acetic acid, ethanol, or formic acid. As the reaction
does not require energy, wind or solar power can be
employed to generate the reaction. Harnessing the ability
to select which chemicals are created will further limit CO₂
transport and storage costs for suppliers in the area as well
as reducing carbon emissions in the environment.
Source: University of Chicago News, 7/10/2024.
INNOVATION
CORNER
Renewable Diesel Margins and Innovation
over Pt-Zn/ZSM-5
Catalysts
This study investigates the reaction mechanism and the
effect of CO₂ in ethane dehydrogenation to ethene using two
different kinds of Pt-Zn/ZSM-5 catalysts. The calculation
findings show that the Pt-Zn sites play various roles, with
Zn₆Pt₁/ZSM-5 being more active than Pt₃Zn₁/ZSM-5 due to
more efficient Pt-Zn sites for dehydrogenation using ZSM5
framework O of ZSM-5. CO₂ combines with H- species
produced by ethane dehydrogenation, resulting in novel
and simple H-consuming pathways, hence boosting the
process. CO₂ has a greater favorable effect on Zn₆Pt₁/
ZSM-5 than on Pt₃Zn₁/ZSM-5 because to the significantly
lower rate-limiting step barrier. Zn₆Pt₁/ZSM-5 significantly
reduces the competitive side reaction of CO₂ with ethyl
species, making it a potential catalyst for ethene production.
This study advances the mechanistic knowledge of CO₂assisted
dehydrogenation of light alkanes over Pt-Zn/
ZSM-5 catalysts and highlights the important role of CO₂,
supporting a useful reference for future catalyst design.
Source: ScienceDirect 7/5/2024.
A recent blog presented by George Hoekstra for RBN
Energy, Inc highlighted a Renewable Diesel (RD) margin
analysis comparing an April 2021 vs April 2024 in the US,
showing current RD plants are struggling to breakeven.
A quick summary is seen in Table 1 below.
Table 1 2021 vs 2024 RD Production Costs and Margin,
$US per Gal
It is clear the current situation is not sustainable today,
perhaps short term. The innovation needed is reducing
the feedstock costs and reducing the production cost.
The former would benefit from alternative biofeedstocks,
perhaps through pyrolysis oils and later from new lower
cost deoxygenation catalysis, without using so much
hydrogen. Are you up for these challenges?
The Catalyst Review
July 2024
5
The Catalyst Review July 2024

Table of Contents for the Digital Edition of The Catalyst Review July 2024
