Styrene Dimers Research Articles

Pyrolysis of polystyrene using low-cost natural catalysts: Production and characterisation of styrene-rich pyro-oils

This work aims to study the catalytic pyrolysis of polystyrene (PS) in order to obtain a styrene-rich liquid appealing for re-polymerisation processes. The process was performed in a fixed-bed reactor using low-cost materials such as ilmenite, olivine, calcium oxide (CaO) and dolomite as catalysts at 600 ºC. A non-catalytic test with sand was also conducted for comparison purposes. The resulting pyro-oil yield was between 89 and 96 wt%, and consisted mainly of styrene monomer, styrene dimer and styrene trimer, as well as other light aromatic compounds depending on the catalyst used. Olivine and CaO were capable to increase the styrene monomer concentration in the pyro-oil by about 10–12 % compared to non-catalytic pyrolysis, reaching up to 74.5 and 71.4 wt%, respectively. Furthermore, these catalysts reduced the concentration of styrene dimer and styrene trimer in the pyro-oil, which could be useful for further re-polymerisation processes. However, the presence of polyaromatics (PAHs) in the pyro-oils obtained from ilmenite, olivine and CaO was also identified, and other families such as mono-aromatics, di-aromatics, BTX, and nitrogen heterocyclic compounds were also increased in all pyro-oils obtained with catalysts compared to those obtained by non-catalytic pyrolysis. In addition, several inorganic species in the pyro-oil were reduced by the addition of the catalysts. This effect was observed after the addition of olivine and CaO, especially in the reduction of S, Mg, Ca and Fe. These results clearly demonstrate the potential of pyrolysis to convert PS waste into valuable building blocks for the production of new plastics.

Thermodynamic and economic analysis of a deployable and scalable process to recover Monomer-Grade styrene from waste polystyrene

Less than 5% of polystyrene is recycled, motivating a search for energy efficient and economical methods for polystyrene recycling that can be deployed at scale. One option is chemical recycling, consisting of thermal depolymerization and purification to produce monomer-grade styrene (>99%) and other co-products. Thermal depolymerization and distillation are readily scalable, well-established technologies; however, to be considered practical, they must be thermodynamically efficient, economically feasible, and environmentally responsible. Accordingly, mass and energy balances of a pyrolysis reactor for thermal depolymerization and two distillation columns to separate styrene from α-methyl styrene, styrene dimer, toluene, and ethyl benzene co-products, were simulated using ASPEN to evaluate thermodynamic and economic feasibility. These simulations indicate that monomer-grade styrene can be recovered with energy inputs <10MJ/kg, comparable to the energy content of pyrolysis co-products. Thermodynamic sensitivity analysis indicates the scope to reduce these values and enhance the robustness of the predictions. A probabilistic economic analysis of multiple scenarios combined with detailed sensitivity analysis indicates that the cost for recycled styrene is approximately twice the historical market value of fossil-derived styrene when styrene costs are fixed at 15% of the total product cost or less than the historical value when feedstock costs are assumed to be zero. A Monte Carlo and Net Present Value-based economic performance analysis indicates that chemical recycling is economically viable for scenarios assuming realistic feedstock costs. Furthermore, the CO2 abatement cost is roughly $1.5 per ton of averted CO2, relative to a pyrolysis process system to produce fuels. As much as 60% of all polystyrene used today could be replaced by chemically recycled styrene, thus quantifying the potential benefits of this readily scalable approach.

Selective Palladium(II)‐Catalyzed Dimerization of Styrenes and Acrylates in Molten Tetrabutylammonium Acetate as an Ionic Liquid

AbstractA method for the selective dimerization of styrenes and acrylates has been developed. The reaction is catalyzed by a very low amount of palladium acetate in molten tetrabutylammonium acetate without the need for any additional ligand. The use of this method enabled the coupling of substituted vinyl arenes in reasonable yields to give exclusively the (E,E)‐1,4‐diarylbutadiene motif within 7–10 h. Acrylates, on the other hand, exhibit higher reactivity, and the use of dibutyl acrylate resulted in the quantitative synthesis of dibutyl 2‐methyleneglutarate in less than 2 h. This selectivity is unprecedented in the literature. The role of the ionic liquid and the different catalytic pathways involved in the two processes were also elucidated.

Polymeric liquids in mesoporous photonic structures: From precursor film spreading to imbibition dynamics at the nanoscale

Polymers are known to wet nanopores with high surface energy through an atomically thin precursor film followed by slower capillary filling. We present here light interference spectroscopy using a mesoporous membrane-based chip that allows us to observe the dynamics of these phenomena in situ down to the sub-nanometer scale at milli- to microsecond temporal resolution. The device consists of a mesoporous silicon film (average pore size 6 nm) with an integrated photonic crystal, which permits to simultaneously measure the phase shift of thin film interference and the resonance of the photonic crystal upon imbibition. For a styrene dimer, we find a flat fluid front without a precursor film, while the pentamer forms an expanding molecular thin film moving in front of the menisci of the capillary filling. These different behaviors are attributed to a significantly faster pore-surface diffusion compared to the imbibition dynamics for the pentamer and vice versa for the dimer. In addition, both oligomers exhibit anomalously slow imbibition dynamics, which could be explained by apparent viscosities of six and eleven times the bulk value, respectively. However, a more consistent description of the dynamics is achieved by a constriction model that emphasizes the increasing importance of local undulations in the pore radius with the molecular size and includes a sub-nanometer hydrodynamic dead, immobile zone at the pore wall but otherwise uses bulk fluid parameters. Overall, our study illustrates that interferometric, opto-fluidic experiments with mesoporous media allow for a remarkably detailed exploration of the nano-rheology of polymeric liquids.

Multiple linear regression and artificial neural networks for highly selective cationic β‐diimine‐methallyl nickel (II) catalyst for styrene dimerization reaction to 1,3‐diphenyl‐1‐butene

The objective of the present study is to develop predictive models to input and output parameters for linear styrene dimerization reactions. These reactions involve the conversion of two styrene molecules into 1,3‐diphenyl‐1‐butene, which is a commonly used intermediate in the production of various industrial chemicals. Multiple linear regression (MLR) and artificial neural network based on multilayer perceptron (MLP) and radial basis function were used to model 1,3‐diphenyl‐1‐butne dimerization process in order to evaluate its performance. The neural network has been trained and tested by experimental data. The effect of various parameters (such as complex concentration) on styrene conversion (Conv%) and turnover of frequency (TOF) has been investigated in the proposed work. The results found by the proposed predictive models were analyzed and compared with the experimental results. Based on the comparison of the results, the radial basis function neural network (RBFNN) model outperformed the other models (MLR and MLP) with a correlation coefficient of (0.987 for Conv% and 0.947 for TOF) and lower root mean square errors for the output parameters. This result demonstrates that the RBFNN is an efficient technique to predict the styrene conversion and turnover frequency of the dimerization reaction. It was exposed that the control strategies learned are robust and can be transferred to similar dimerization reaction configurations.

Effect of time on alternative hydrocarbon production from waste PS with biodiesel of candlenut oil using catalytic cracking and Si/Al-Ceramic as catalyst

In the present study, the catalytic cracking process of polystyrene (PS) plastic waste and biodiesel of candlenut oil was carried out using Si/Al-ceramic catalyst with a mass ratio of 7:3 at 300 °C. This study aimed to investigate the effect of reaction time on the distribution of hydrocarbon fuel fractions produced. They are characterized by XRD, SEM-EDX, FTIR, and N2 gas adsorption-desorption. The products components of PS catalytic cracking were analyzed by gas chromatography-mass spectroscopy (GC-MS). The liquid fuel obtained was mixed with commercial fuel, Premium RON 88, and methyl tertiary butyl ether (MTBE) additive to determine its physicochemical properties and performance in a generator engine with gasoline-based fuel. The result showed that an increase in reaction time from 60 minutes to 120 minutes of PS cracking over Si/Al-Ceramic catalyst leads to the enrichment of long-chain hydrocarbon fraction (&gt; C12) by 25.61% which is attributed to the formation of styrene dimer. The fuel has thermal efficiency of 26.49% with density of 0.7405 g/cm3, flashpoint of &lt; -50 °C, calorific value of 9642.42 kcal/kg, and octane number of 92.2. These characteristics are in accordance with SNI 06-3506-1994 standard. Therefore, liquid fuel from catalytic cracking of polystyrene plastic wastes can be used as a potential alternative fuel in the gasoline range.

Identification of polystyrene nanoplastics from natural organic matter in complex environmental matrices by pyrolysis-gas chromatography-mass spectrometry.

Due to the flux of plastic debris entering the environment, it becomes urgent to document and monitor their degradation pathways at different scales. At the colloidal scale, the systematic hetero-association of nanoplastics with the natural organic matter complexifies the ability to detect plastic signatures in the particle collected in the various environments. The current techniques used for microplastics could not discriminate the polymers at the nanoscale from the natural macromolecules, as the plastic mass in the aggregate is within the same order. Only a few methods are available concerning nanoplastics identification in complex matrices, with the coupling of pyrolysis with gas chromatography and mass spectrometry (Py-GC-MS) as one of the most promising due to its mass-based detection. However, natural organic matter in environmental samples interferes with similar pyrolysis products. These interferences are even more critical for polystyrene polymers as this plastic presents no dominant pyrolysis markers, such as polypropylene, that could be identified at trace concentrations. Here, we investigate the ability to detect and quantify polystyrene nanoplastics in a rich phase of natural organic matter proposed based on the relative ratio of pyrolyzates. The use of specific degradation products (styrene dimer and styrene trimer) and the toluene/styrene ratio (RT/S) are explored for these two axes. While the size of the polystyrene nanoplastics biased the pyrolyzates of styrene dimer and trimer, the RT/S was correlated with the nanoplastics mass fraction in the presence of natural organic matter. An empirical model is proposed to evaluate the relative quantity of polystyrene nanoplastics in relevant environmental matrices. The model was applied to real contaminated soil by plastic debris and literature data to demonstrate its potential.

Bayesian tuned kinetic Monte Carlo modeling of polystyrene pyrolysis: Unraveling the pathways to its monomer, dimers, and trimers formation

The current kinetic models for polystyrene (PS) pyrolysis contain many simplifications to reduce their size and the corresponding simulation time. Moreover, they are often based on rate coefficients determined using non-ideal experimental data featuring ambiguous process conditions with respect to mixing and temperature uniformity. The practical interest of PS pyrolysis is the production of styrene monomer to be reused as a feedstock in the polymerization of styrene. In the present work, a lab-scale tree-based kinetic Monte Carlo (kMC) model is presented that differentiates between 18 reaction families and 26 end-group pairs to study the product yield variations for thermal degradation of PS. Model parameters follow from Bayesian optimization to experimental data recorded with an in-house micro-pyrolysis unit coupled with comprehensive two-dimensional gas chromatography. Low chain length (CL) anionic-made PS is specifically considered to gain an understanding of the role of specific end-groups. The experimental yields of the major products (monomer: 74.7–80.8 wt%, dimer: 5.1–5.5 wt%, trimer: 1.6–7.7 wt%) are well-predicted with the fine-tuned parameters. The main reaction pathway in the formation of styrene monomer is end-chain β-scission, while mid-chain β-scission is primarily involved in the formation of the styrene dimer and trimer. Our model shows that the pyrolysis of low CL anionic-made PS leads to better rate coefficients than those obtained from state-of-the-art pyrolysis of long CL PS, in which end-groups play a much smaller role.

Taming Highly Unstable Radical Anions and 1,4-Organodilithiums by Flow Microreactors: Controlled Reductive Dimerization of Styrenes.

The reduction of styrenes with lithium arenide in a flow microreactor leads to the instantaneous generation of highly unstable radical anions that subsequently dimerize to yield the corresponding 1,4-organodilithiums. A flow reactor with fast mixing is essential for this reductive dimerization as the efficiency and selectivity are low under batch conditions. A series of styrenes undergo dimerization, and the resulting 1,4-organodilithiums are trapped with various electrophiles. Trapping with divalent electrophiles affords precursors for useful yet less accessible cyclic structures, for example, siloles from dichlorosilanes. Thus, we highlight the power of single-electron reduction of unsaturated compounds in flow microreactors for organic synthesis.

Influence of particle characteristics, heating temperature and time on the pyrolysis product distributions of polystyrene micro- and nano-plastics

Pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS) has been widely used for the detection of micro- and nanoplastics (MNPs) in the environment. However, there is a lack of thorough investigation on the effects of pyrolysis temperature and time, as well as the particle source, size and mass of MNPs on the pyrolysis efficiency and pyrolysis product distribution of MNPs. Herein, taking the common plastics polystyrene (PS) as a model, we systematically evaluated the influences of the above factors on the pyrolysis of PS MNPs. Results showed that pyrolysis temperature and time significantly affect the pyrolysis efficiency. By measuring the relative response values of the indicator compound styrene trimers to styrene monomer, the optimum condition was determined as the temperature of 510 ℃ and pyrolysis time longer than 18 s. Meanwhile, the mass of MNPs also affected the distribution of PS pyrolysis products. The proportions of styrene dimers and trimers increased slightly with PS MNP mass, while the source, particle size of MNPs have little effect on the pyrolysis product distribution. This work proposed a suitable pyrolysis temperature and time for the determination of PS by Py-GC/MS, which would contribute to the accurate analysis of PS MNPs in the environment.

β-Diimine-methallyl nickel complexes in ionic liquid: A biphasic green system for the high selective styrene dimerization

The selective head-to-tail dimerization of styrene to 1,3-diphenyl-1-butene over [Ni(β-diimine)- (methallyl)]+PF6- / Et2O•HBF4 catalyst system has been investigated. The styrene conversion up to 95 % and the TOF (TOF = 508 h−1) were reached after optimization of the reaction parameters (temperature: T = 80 °C; time: t = 1 h…) with selectivity to E-1,3-diphényl-1-butene stereoisomer up to 98%. Solvents and diimine ligands have a strong effect on the catalyst activity.The substituents on the β-diimine ligands have a crucial effect on the conversion but did not affect the selectivity. Cationic β-diimine-nickel (2 + ) is the likely active species.Reaction products were characterized by 1H and 13C NMR, IR, and GC–MS spectroscopies.

Qualitative Evaluation of Factors Inducing Environmental Pollution of the Sandy Beaches of Jeju Island Using Styrene Oligomers

Objectives : Plastic pollution is a very important environmental issue in Korea as well as abroad. The objective of this study is to evaluate the internal and external factors that cause pollution of the coastal environment of Jeju Island using styrene oligomers (SOs) originated from polystyrene (PS) plastic.Methods : In order to achieve the above objective, this study is conducted to quantitatively measure the concentration of 12 individual SOs chemicals, through gas chromatography/mass spectroscopy (GC/MS) analyzing seawater and beach sand samples around sandy beaches in Jeju Island. This study evaluates the degree of environmental pollution according to internal or external factors of the sandy beach by using the physicochemical characteristic that SOs species are adsorbed on the surface of sand particles.Results and Discussion : The average concentration of SOs in the beach sand of Jeju Island ranges from a minimum of 9.80 ng/g to a maximum of 13.62 ng/g, and the average concentration of SOs in seawater is relatively low with a constant 0.05 to 0.11 µg/L. Although the concentration distribution of SOs species differs considerably depending on the sample collected, the concentration of SOs decreases in the order of styrene trimers (7 isomers) &gt; styrene dimers (4 isomers) &gt; styrene monomer. As a result of monitoring, the concentration of SOs at the sandy beaches of Jeju Island is much higher in the beach sand than in the seawater. This result means that the major beaches of Jeju Island can be polluted mainly by internal factors (e.g. population density, number of travelers according to population movement, and so on), because SOs species are adsorbed on the surface of the sand particles and their mobility is limited.Conclusions : This study shows that the sandy beaches of Jeju Island are mainly polluted by internal factors. It is thought that the pollution degree of the sandy beaches is the highest in the order of Gwakji Beach &lt; Samyang Beach, Hamdeok Beach, Pyoseon Beach &lt; Ihoteho Beach, Sagye Beach &lt; Seopjikoji Beach, Gimnyeong Beach, and Hyeopjae Beach. This study is expected to contribute to the evaluation of the causes of plastic pollution in the coastal environment of Jeju Island.

Solvent-Resistant Thin-Film Composite Membranes from Biomass-Derived Building Blocks: Chitosan and 2,5-Furandicarboxaldehyde

To address the increasing interest in environmental issues, green and sustainable material-based membranes have attracted significant research interest with the promise to replace fossil-based membranes and to reduce waste generation. In this work, more sustainable thin-film composite (TFC) membranes are designed and fabricated via interfacial polymerization of green building blocks, namely, shrimp farming waste chitosan in the aqueous phase and plant-based 2,5-furandicarboxaldehyde in the organic phase, on an upcycled polyethylene terephthalate porous support. The TFC membranes showed excellent acetone permeance up to 12 L m–2 h–1 bar–1 with a molecular weight cutoff value of approximately 317 g mol–1. The membrane separation performance was optimized by fine-tuning the building block concentrations, which provided a new upper-bound in the plot of acetone permeance versus styrene dimer rejection. In addition, for the first time, TamiSolve was employed as a green solvent to activate the selective layer of the chitosan-based TFC membrane, resulting in a significant enhancement in the permeance of diverse pure solvents including ethanol, methyl ethyl ketone, acetone, and acetonitrile with no remarkable defects and high solute rejections. Our proposed green TFC fabrication platform enables the replacement of toxic and fossil-based solvents and reagents in developing high-performance and solvent-resistant nanofiltration membranes.

Pyrolysis of common plastics and their mixtures to produce valuable petroleum-like products

In the present study, polystyrene (PS), low-density polyethylene (LDPE), high-density polyethylene (HDPE), polypropylene (PP), and their mixture undergo intermediate isothermal pyrolysis at 450 °C, 500 °C, 550 °C, and 600 °C inside a tubular semi-continuous reactor under an inert nitrogen atmosphere. The liquid pyrolytic oil samples recovered in each case were analyzed through gas chromatography-mass spectrometry (GC–MS) and flame ionization detector (GC-FID) to identify and quantify the different products formed. It was found that polyethylenes (HDPE and LDPE) behave similarly in these pyrolysis conditions. For instance, GC analysis showed consecutive triplet series of linear aliphatic hydrocarbons at each carbon number of the alkane, 1-alkene, 1,(N-1)-alkadiene where N is the carbon number. On the other hand, PP, LDPE, and HDPE pyrolytic oil were rich in olefinic compounds. However, the case was quite different for PS. The pyrolytic oil was constituted totally of aromatic compounds ranging from mono to tri aromatic hydrocarbons. Styrene was the main product, along with other products such as styrene dimer, styrene trimer, benzene, toluene, bibenzyl, and α-methylstyrene. Results showed an increase in lighter hydrocarbons as the temperature increased, especially for styrene, where the weight fraction in the oil increased from 40 wt.% to 60 wt.%. Ultimately, a synergistic effect was observed with mixed plastic pyrolysis, yielding lighter compounds with a lower liquid quantity. In addition, the quality of the oil seems to be improved by the increase of around 10 wt.% of both aromatic and light compounds from the expected value at the expense of the heavier fraction. The computed lower heating value (LHV) for gaseous and liquid products ranged between 40 MJ/kg and 51 MJ/kg. A quick glance at the possible end use of each oil was investigated along with a principal component analysis (PCA) on the pyrolytic oil.

Organic solvent reverse osmosis using CuAAC-crosslinked molecularly-mixed composite membranes

Molecularly-mixed composite membranes (MMCMs) incorporating amorphous scrambled porous organic cages (ASPOCs) are a rapidly emerging membrane class that are characterized by the formation of a solid solution due to a high degree of homogeneity that is not observed in other classes of polymer-particle composites. Molecular-level mixing overcomes many of the performance/processing issues typically encountered with two phase composite materials. However, chemical stabilization of the polymer matrix can deactivate the ASPOC cages. Here, we illustrate an alternative method of crosslinking Matrimid® in MMCMs using the copper catalyzed azide alkyne cycloaddition (CuAAC) click reaction. We fabricated thin film composite membranes and benchmarked them in a crossflow permeation system with standard styrene oligomers dissolved in a variety of organic solvents as well as an exemplar organic solvent reverse osmosis separation. We found that the presence of ASPOC increased both permeance and styrene dimer separation factor by up to 79% and 154%, respectively, over crosslinked Matrimid depending on the solvent, although the separation factor decreased at higher ASPOC loadings. The crosslinked MMCMs were challenged with a solvent-solvent separation in an organic solvent reverse osmosis modality and were able to effectively purify toluene from triisopropylbenzene. This work provides experimental observations needed to understand the mass transport processes occurring in MMCMs and highlights their separation performance and scale-up potential.

Reinforcing the polybenzimidazole membrane surface by an ultrathin co-crosslinked polydopamine layer for organic solvent nanofiltration applications

Here, highly robust and tight PBI-based OSN membranes were developed by reinforcing the active layer with an ultrathin polydopamine (pDA) coating followed by the simultaneous co-crosslinking of the pDA-coated PBI membrane. Although the pDA layer thickness was just under 5 nm, the pDA layer can effectively improve the rejection properties of the pristine PBI membrane by reducing the overall pore size and filling the defects at the membrane surface. The chemical and physical changes clearly showed the effect of the ultrathin pDA layer and co-crosslinking on the membrane properties and separation performance. The modified PBI membranes showed the improved rejection property and excellent stability in various organic solvents, even in polar aprotic solvents. The co-crosslinked pDA-coated PBI membranes showed a very high rejection properties to low molecular weight solutes (97.6% for 236 Da styrene dimer and 99.9% for 308 Da PPG) with stable solvent permeance. Moreover, significantly improved solvent permeances were observed without a notable decrease in the rejection performance after the prefiltration of polar aprotic solvents. The results showed the effective separation performance enhancement of OSN membranes by ultrathin pDA coating and the potential applications of solvent purification, reuse and valuable chemical recovery in various fine chemical industries.

Pyrolysis study of cinnamaldehyde model compound with analytical Py-GC×GC-FID/TOF-MS

Aldehyde-type lignin monomers like hydroxycinnamaldehydes are important monomers in plants downregulating the enzyme activity of cinnamyl alcohol dehydrogenase or catechol‐O‐methyltranferase. Cinnamaldehyde (CA) is the simplest aldehyde-type lignin model compound, which is also one of the primary products of cinnamic alcohol. In this contribution the experimental results obtained for the pyrolysis of transcinnamaldehyde (trans-CA) using a unique Py-GC×GC-FID/TOF-MS at temperatures from 573 to 1023 K are reported. Styrene and cis-cinnamaldehyde account for a large fraction of the total product yields at higher temperature. A dimer of styrene detected at higher temperatures (≥ 823 K) suggests the presence of radical reactions. The plausible pyrolytic pathways of major products are proposed. This study is a first step towards a successive model extension to other aldehyde-type monomers such as p-coumaryl, coniferyl and sinapyl aldehydes

Low Temperature Decomposition of Polystyrene

Styrene oligomers (SOs), of styrene (styrene monomer, SM), 1,3-diphenylpropane (styrene dimer, SD1), 2,4-diphenyl-1-butene (styrene dimer, SD2) and 2,4,6-triphenyl-1-hexene (styrene trimer, ST), had been detected in the natural environments far from industrial area. To confirm SOs formation through thermal decomposition of polystyrene (PS) wastes in the nature, purified polystyrene (SO-free PS) has been shown to decompose at 30 to 150 °C. The SO ratio of SM:SD:ST was about 1:1:5 with ST as the main product. Mass spectrometry with selected ion monitoring was used for the quantitative analysis of the trace amounts of SOs. The rate of PS decomposition was obtained as k(year−1)=5.177 exp(−5029/T(K)) based on the amount of ST. Decomposition kinetics indicated that not only does drifting lump PS break up into micro/nano pieces in the ocean, but that it also subsequently undergoes degradation into basic structure units SO. According to the simulation at 30 °C, the amounts of SOs in the ocean will be over 400 MT in 2050.

Thermal depolymerization of polystyrene in highly aromatic hydrocarbon medium

Data from the thermal depolymerization of polystyrene in a highly aromatic hydrocarbon medium (light and heavy cycle oil) have been obtained. The influences of the reaction conditions on the conversion and selectivity have been studied. The maximum yield of styrene obtained in the present work is 84.4% at a polymer conversion of 93.8% in light cycle oil under the following conditions: temperature: 500 °C, vapor residence time: 2.61 s, polymer concentration: 15%. The styrene yield obtained is higher than has been previously reported in the scientific literature. The high selectivity of styrene in the depolymerization reaction can be explained by the fact that under the reaction conditions studied, the formation of styrene dimers in the hydrocarbon medium is inhibited.

Evidence of transport of styrene oligomers originated from polystyrene plastic to oceans by runoff

This study demonstrates for the first time that styrene oligomers (SOs), which are indicators of polystyrene (PS) plastic contamination in the environment, are transported from land to the ocean. Samples of sand and seawater were taken from the coastline of the Tokyo Bay over the past four years, and all samples of both sand and seawater were found to contain SOs such as styrene monomer (SM), styrene dimers (SD), and styrene trimers (ST), with the concentration distributions of these being in the order of ST > SD > SM. The concentrations of these SOs are linearly proportional to monthly precipitation. These results indicate that various land-based SOs sources are connected with the estuary, a substantial amount of which are transported into Tokyo Bay through runoff as overland flow. As a result, runoff by precipitation is a potential transport pathway of land-based SOs sources. This finding is of interest in terms of both the extent of PS plastic pollution and the transport of SOs to the ocean. Capsule abstractThe assessment of the transport of styrene oligomers (SOs) in the coastal environment is performed.