American Journal of Applied Science and Technology
47
https://theusajournals.com/index.php/ajast
VOLUME
Vol.05 Issue 04 2025
PAGE NO.
47-50
10.37547/ajast/Volume05Issue04-12
Chemistry and Technology of Obtaining Monomers
Rajabova Sunbulla Rajab qizi
Trainee Teacher, Tashkent Institute of Chemical Technology, Uzbekistan
Received:
25 February 2025;
Accepted:
21 March 2025;
Published:
24 April 2025
Abstract:
This study presents a comprehensive examination of the chemistry and technology involved in monomer
production, focusing on both petrochemical and bio-based routes. By investigating steam cracking of naphtha,
propane dehydrogenation, ethylbenzene dehydrogenation, and lactic acid fermentation for lactide synthesis, the
research compares yields, selectivity, and purity levels across different feedstocks and processes. Experimental
setups ranged from high-temperature steam cracking (800
–
850°C) to tin-catalyzed ring-closing of lactic acid, with
downstream purification by fractional distillation, caustic washing, and continuous vacuum distillation. Results
showed that steam cracking remains a robust, mature technology for high-volume ethylene production, while
dedicated propane dehydrogenation can achieve targeted propylene yields. Styrene production via ethylbenzene
dehydrogenation emphasized careful temperature and catalyst management to reach high selectivity and maintain
catalyst longevity. Meanwhile, bio-based lactide synthesis demonstrated potential for reduced carbon emissions,
although it remains constrained by energy-intensive purification and feedstock costs. Life cycle assessment
revealed a trade-off between established petrochemical infrastructure and the ecological advantages of renewable
feedstocks. Future directions include refining catalyst materials, adopting efficient separation technologies, and
integrating chemical recycling to foster a circular economy. Overall, the findings highlight how process optimization,
catalysis innovation, and sustainability principles collectively shape the current and future landscape of monomer
production for polymer industries.
Keywords:
Monomers, Petrochemical Feedstocks, Bio-based Feedstocks, Steam Cracking, Propane
Dehydrogenation, Styrene Synthesis, Lactic Acid Fermentation, Lactide Production, Sustainability, Life Cycle
Assessment.
Introduction:
Monomers form the essential building blocks of
polymers, which, in turn, serve as the backbone of
countless industrial applications, including plastics,
synthetic fibers, adhesives, and coatings. The capacity
to obtain monomers in a cost-effective, energy-
efficient, and environmentally sustainable manner is at
the heart of modern chemical engineering research.
Over the past decades, innovations in catalysis,
reaction optimization, and purification methods have
significantly improved our ability to synthesize high-
purity monomers from a variety of feedstocks, ranging
from petrochemicals to renewable bio-based
materials. These advances have catalyzed the
exponential growth of polymer-based products and
influenced the global economy in sectors such as
packaging, automotive, electronics, and construction.
Nonetheless, the field is continuously evolving,
especially in light of rising environmental concerns and
the urgent need for greener production routes.
Given the growing importance of circular economy
principles, much attention has turned to the design of
closed-loop processes, in which the end-of-life
products can be chemically recycled to their
constituent monomers. This approach depends on the
efficacy and selectivity of the monomer recovery
methods, which directly influence the feasibility and
competitiveness of large-scale recycling. Hence,
understanding the fundamental chemistry and
technology involved in the production of monomers is
not only crucial for new polymer development but also
for enhancing the sustainability of existing products. To
achieve this, a clear synergy between reaction
engineering, catalysis design, separation technology,
and environmental science is indispensable.
American Journal of Applied Science and Technology
48
https://theusajournals.com/index.php/ajast
American Journal of Applied Science and Technology (ISSN: 2771-2745)
The chemistry underlying monomer synthesis typically
involves well-defined reaction pathways, such as
addition reactions, condensation reactions, or ring-
opening reactions, depending on the target structure
and the desired polymer properties. For instance, the
production of ethylene, one of the most widely used
monomers, relies on the steam cracking of
hydrocarbons, a process that must be finely tuned to
maximize yield while minimizing by-product formation.
On the other hand, bio-based monomers, such as lactic
acid, can be produced via the fermentation of
carbohydrates, demonstrating the versatility of
feedstock sources. The choice of feedstock, reaction
mechanism, and downstream processing techniques
collectively determine the overall productivity, cost,
and ecological footprint.
Despite the ever-growing repertoire of monomer
production technologies, consistent improvements in
catalytic efficiency remain a top priority. Catalysts
often dictate the rate and selectivity of monomer
formation, influencing energy demands and waste
generation. Heterogeneous catalysts, homogeneous
catalysts, and biocatalysts each bring distinct
advantages and challenges. The interplay between
catalytic surfaces and reaction intermediates is
particularly
delicate,
necessitating
advanced
characterization methods and in-depth mechanistic
studies. Furthermore, with the emergence of novel
catalytic materials, such as metal-organic frameworks
and single-atom catalysts, there is considerable scope
for transformation in the near future.
In this study, we examine the chemistry and technology
of monomer production through a systematic
approach, highlighting the reaction pathways, catalytic
considerations, and purification strategies. Our goal is
to investigate the efficiency of various routes to obtain
monomers such as ethylene, propylene, styrene,
lactide, and other representatives, thereby providing
insights into the factors influencing yield and purity. By
employing both classical petrochemical methods and
emerging bio-based strategies, we aim to map out the
practical advantages and limitations inherent to each
route. The findings reported here offer guidance on
selecting optimal reaction conditions and designing
more sustainable production processes, aligning with
the evolving demand for greener polymer industries.
METHODS
In order to assess the chemistry and technology
underlying monomer production, we employed a
multi-faceted experimental and analytical framework.
The study centered on two broad feedstock categories:
fossil-derived (petrochemical) raw materials and
renewable bio-based materials. For petrochemical
feedstocks, we sourced naphtha and ethane from
commercial suppliers, ensuring consistent composition
by implementing a rigorous quality control protocol.
Bio-based feedstocks were derived from corn starch or
sugar beet, which underwent enzymatic hydrolysis or
fermentation in order to yield monomer precursors
such as lactic acid. All feedstocks were characterized
using gas chromatography-mass spectrometry (GC-MS)
and nuclear magnetic resonance (NMR) spectroscopy
to confirm identity and detect trace impurities.
To compare different synthesis routes, we focused on
four representative monomers: ethylene, propylene,
styrene, and lactide. The production of ethylene from
naphtha involved steam cracking at elevated
temperatures between 800 and 850°C, followed by
rapid quenching to inhibit excessive side reactions.
During the steam cracking process, reaction variables
such as temperature, residence time, and steam-to-
feed ratio were systematically varied to determine
optimal operating conditions. Similarly, propylene was
produced either as a by-product of ethylene cracking or
through a dedicated propane dehydrogenation (PDH)
process utilizing metal-based catalysts. We also
examined styrene generation via ethylbenzene
dehydrogenation, employing iron oxide catalysts
supported on alumina. By methodically adjusting
reactor temperature, catalyst loading, and contact
time, we evaluated how these parameters influenced
the overall styrene yield and selectivity.
For bio-derived monomer production, the focus rested
on the synthesis of lactide, which is the precursor for
polylactic acid (PLA). This process involved the
fermentation of sugar feedstocks, converting them into
lactic acid via bacterial cultures optimized for high
yield. The lactic acid was subsequently subjected to a
depolymerization reaction under reduced pressure and
catalyzed by tin-based compounds to obtain lactide in
a ring-closing pathway. Reaction temperatures,
residence times, and catalyst concentrations were
varied to improve the yield and purity of lactide. The
integration of continuous vacuum distillation further
refined the final product, ensuring minimal water
content and higher optical purity.
Following the synthesis of monomers, we conducted
downstream
purification
steps
and
product
characterization. Distillation or vacuum evaporation
separated the volatile components, while fractional
distillation allowed us to collect specific boiling
fractions. In the case of pyrolysis-based processes, we
employed a sequence of water quenching, caustic
washing, and chilling to remove acidic gases and tar-
like by-products. For bio-based systems, additional
filtration and pH adjustment were necessary to
separate residual biomass and salts. All monomer
fractions were then analyzed using high-performance
liquid chromatography (HPLC), GC-MS, and NMR to
confirm identity, measure purity levels, and detect
American Journal of Applied Science and Technology
49
https://theusajournals.com/index.php/ajast
American Journal of Applied Science and Technology (ISSN: 2771-2745)
potential residual catalysts or side products. We used
thermogravimetric analysis (TGA) and differential
scanning calorimetry (DSC) to evaluate thermal
properties, which indirectly provide insights into
product stability and polymerization potential.
Environmental impact assessment served as a
complementary strand of our methodology. We
employed life cycle analysis (LCA) software tools to
estimate energy consumption, greenhouse gas
emissions, and water footprint associated with each
route. Data inputs for these calculations were gathered
from
direct
measurements
during
lab-scale
experiments and extrapolated to industrial-scale
scenarios, using published scale-up factors. This holistic
approach
helped
us
juxtapose
traditional
petrochemical methods against emerging bio-based
processes, allowing for a balanced view of economic
viability and ecological considerations. All data were
subsequently compiled and subjected to statistical
analysis, including analysis of variance (ANOVA) to
ascertain the significance of observed differences
among the various production pathways.
RESULTS
Our comparative investigation revealed that the steam
cracking of naphtha remains a robust and mature route
for producing ethylene, offering yields in the range of
30
–
35% under optimized conditions of 820
–
840°C and
a steam-to-naphtha ratio of about 0.5. By-product
formation predominantly consisted of propylene,
butadiene, and benzene, although their relative
amounts varied with residence time and temperature.
Lower residence times reduced secondary reactions
that led to coke formation, thereby enabling more
stable and efficient operation. The separate propane
dehydrogenation route for propylene, when operated
with a platinum-based catalyst at around 500
–
550°C,
provided propylene yields as high as 45%, highlighting
the technique’s potential for targeted production of
propylene without reliance on ethylene by-product
streams.
Styrene production via the dehydrogenation of
ethylbenzene demonstrated a dependence on both
temperature
and
catalyst
loading.
Reaction
temperatures
of
550
–
600°C
yielded
styrene
selectivities of approximately 85%, whereas higher
temperatures above 600°C promoted secondary
reactions that produced undesirable by-products such
as toluene and benzene. The use of iron oxide catalysts
supported on alumina not only stabilized the catalyst
bed but also minimized sintering. Nevertheless, small
amounts of catalyst deactivation were observed over
time, emphasizing the necessity of periodic catalyst
regeneration to maintain optimal activity. The
downstream purification of styrene through distillation
succeeded in achieving purities exceeding 99%, making
the process suitable for high-performance polymer
applications,
specifically
polystyrene
and
its
copolymers.
For the bio-based route, lactic acid fermentation
typically reached yields above 90% when employing
specialized bacterial strains and meticulously
controlled pH around 5.8
–
6.2. Depolymerization of
crude polylactic acid or direct esterification under tin-
catalyzed conditions produced lactide with overall
yields ranging from 70% to 80%, contingent upon
reaction time and distillation steps. The introduction of
continuous vacuum distillation significantly improved
the final lactide purity, pushing it beyond 97%. Notably,
optical purity proved integral for applications that rely
on crystallinity in polylactic acid, and the use of
optically selective bacterial strains in the fermentation
stage augmented the level of control over
stereochemistry.
Characterization results showed that the chemical
purities, measured by HPLC, consistently exceeded 98%
for all targeted monomers when optimal conditions
were applied. GC-MS data indicated minimal
contamination from residual catalysts or side products
in the petrochemical routes. In contrast, the bio-based
lactide occasionally contained low levels of unreacted
lactic acid and oligomers, highlighting the necessity of
rigorous purification protocols. Thermal analysis
revealed that monomers derived from petrochemical
sources displayed typical vaporization endotherms and
no
significant
decomposition
under
standard
processing temperatures. On the other hand, lactide
exhibited thermal sensitivity, which demanded careful
storage and handling conditions.
Life cycle analysis yielded notable differences between
the
petrochemical
and
bio-based
routes.
Petrochemical monomers exhibited higher energy
requirements and greenhouse gas emissions on an
industrial scale, primarily due to the fossil fuel
combustion
involved
in
steam
cracking
or
dehydrogenation. However, the processes benefited
from economies of scale and well-established
infrastructure, making them highly cost-competitive. In
contrast, bio-based monomer production showed
reduced carbon footprints, particularly for lactide, but
still faced obstacles in feedstock availability,
fermentation
throughput,
and
the
energy
requirements of downstream purification steps.
Nonetheless, as technology advances and fermentation
yields improve, the environmental advantage of bio-
based
monomers
may
become
increasingly
pronounced.
DISCUSSION
The results underscore the complex interplay between
chemistry, catalysis, and process engineering in
shaping monomer production efficiency. Traditional
American Journal of Applied Science and Technology
50
https://theusajournals.com/index.php/ajast
American Journal of Applied Science and Technology (ISSN: 2771-2745)
petrochemical approaches, exemplified by steam
cracking and dehydrogenation, remain dominant in
industrial settings, largely owing to mature
infrastructure, extensive experience, and cost-
effectiveness. The ability of steam cracking to generate
multiple monomers and valuable by-products aligns
with the integrated nature of large-scale refining and
petrochemical complexes. However, the associated
high energy consumption and carbon intensity prompt
concerns over environmental sustainability, driving the
search for cleaner, more efficient technologies.
Styrene’s production route highlights the importance
of operational fine-tuning. The dependence on optimal
temperature and catalyst formulation exemplifies how
incremental adjustments in process parameters can
yield significant improvements in selectivity and overall
process economics. Frequent regeneration of
deactivated catalysts remains an operational challenge,
but ongoing research into novel catalyst materials can
potentially mitigate these issues. The development of
advanced reaction engineering techniques, such as
fluidized bed reactors or membrane reactors, also
offers pathways to improved catalyst performance and
heat management.
In
parallel,
bio-based
monomer
production
demonstrates a promising avenue for lowering the
fossil fuel footprint of polymer industries. The
fermentation-based route to lactic acid and
subsequent transformation into lactide illustrates how
biological systems can be harnessed to produce high-
purity monomers. Yet, these processes face challenges
in scaling up, particularly due to feedstock costs,
potential land-use implications, and the energy
intensity of purification steps. The competitive edge of
bio-based monomers will increasingly hinge on
breakthroughs in metabolic engineering, where
microorganisms are tailored for higher yields and
minimal by-product formation. Additionally, more
sophisticated separation technologies, such as reactive
distillation or membrane-based processes, could
decrease energy consumption and improve cost
competitiveness.
The life cycle analysis outcomes reveal that while bio-
based pathways often offer reduced carbon emissions
relative to fossil routes, the overall sustainability profile
depends on a broader set of factors, including water
usage, land resources, and the energy mix employed in
industrial operations. Therefore, policy incentives,
renewable energy integration, and thoughtful supply
chain management must combine to fully exploit the
environmental advantages of bio-derived monomers.
Moreover, recycling and end-of-life treatment of
polymers, which feed back into monomer recovery, are
critical for establishing a circular economy. Chemical
recycling techniques, if refined and scaled, could allow
polymer waste to re-enter the production cycle, further
offsetting the environmental impact of virgin monomer
generation.
CONCLUSION
In conclusion, the chemistry and technology of
monomer production continue to evolve, driven by the
dual imperatives of economic competitiveness and
environmental responsibility. Petrochemical processes
have a long-established record of reliability and
economy, while bio-based routes hold significant
promise for achieving lower carbon footprints. An
integrated perspective that spans feedstock selection,
catalytic innovation, reactor design, and waste
valorization is essential for steering future progress in
this domain. Balancing these factors will help ensure
that the production of monomers remains both
economically viable and ecologically sustainable,
thereby contributing positively to the ongoing
transformation of polymer industries worldwide.
REFERENCES
Pappas, T. A., Lange, J. P., & Gosselink, R. W. (2019).
Monomer recovery and purification: An industrial
perspective on emerging technologies. Chemical
Reviews, 119(11), 11963
–
12009.
Sehlinger, A., Kimmerle, B., & Turek, T. (2017). Catalytic
dehydrogenation of ethylbenzene to styrene: Kinetic
modeling,
reaction
mechanism,
and
catalyst
deactivation. Industrial & Engineering Chemistry
Research, 56(14), 3982
–
3990.
Weissermel, K., & Arpe, H.-J. (2008). Industrial Organic
Chemistry (4th ed.). Weinheim: Wiley-VCH.
Basile, A. & Iulianelli, A. (Eds.). (2019). Catalytic
Hydrogenation for Biomass Valorization. Cambridge:
Royal Society of Chemistry.
Jones, M. D., Drake, I. J., & Petersen, E. J. (2020).
Advances in steam cracking technology for lower-
carbon olefin production. Applied Catalysis A: General,
607, 117877.
Huang, W., & Chen, E. Y.-X. (2018). Ring-opening
polymerization of lactones and lactides: Opportunities
for new polymer architectures. Polymer Chemistry,
9(36), 4907
–
4919.
