Polyvinyl Chloride Products Research Articles

A joint economic evaluation and FP2O techno-economic resilience approach for evaluation of suspension PVC production

The production of polyvinyl chloride (PVC) involves obtaining a thermoplastic polymer from vinyl chloride monomer (VCM) and ethylene, primarily through the suspension method. This process is vital for manufacturing various products, such as pipes and coatings. However, its high-energy consumption necessitates economic evaluations to assess feasibility. In this work, a dual approach is proposed: a Feedstock-Processing-Product-Operation (FP2O) based techno-economic resilience analysis via sensitivity analysis alongside economic evaluation. The study evaluated a PVC production process with a capacity of 518,400 t/y of VCM over a 15-year plant lifespan. The techno-economic assessment revealed a Total Capital Investment of $609, 882, 203, a Payback Period of 4.22 years, and a Return on Investment of 14.38 %. Positive Net Present Value and a cost/benefit ratio >1 indicate the plant's installation under proposed conditions is favorable. Additionally, the technical-economic resilience analysis identified the process's response to changes in PVC price, raw material costs, and production capacity, guiding improvement actions pre- and post-plant assembly.

Development and prospect of the acetylene production chain based on the process systems engineering: a focus on the polyvinyl chloride production

Development and prospect of the acetylene production chain based on the process systems engineering: a focus on the polyvinyl chloride production

Enhancing predictive monitoring of ethylene oxychlorination reactor states through spatiotemporal coupling analysis

The production of polyvinyl chloride (PVC) encounters challenges stemming from the temporal and spatial coupling characteristics inherent in the fixed bed ethylene oxychlorination process. Consequently, the implementation of enhanced safety measures and risk reduction strategies becomes imperative. This study introduces a pioneering methodology leveraging a spectral temporal graph neural network. By leveraging reactor temperature data, spatial variable decoupling facilitated by the Fourier transform, and a self-attentive mechanism within graph neural networks, the proposed approach adeptly forecasts future reactor states. The model's seamless alignment with the physical knowledge of reaction processes, validated through the adjacency matrix and hotspot region identification, underscores its efficacy in ensuring process safety and mitigating operational risks in PVC production. Empirical findings further validate the effectiveness of the approach, with predictions demonstrating an error margin of less than 0.5°C in forecasting future reactor temperatures.

A common phthalate replacement disrupts ovarian function in young adult mice.

Di-2-ethylhexyl terephthalate (DEHTP) is a replacement for its structural isomer di-2-ethylhexyl phthalate (DEHP), a known endocrine disrupting chemical and ovarian toxicant. DEHTP is used as a plasticizer in polyvinyl chloride products and its metabolites are increasingly found in biomonitoring studies at levels similar to phthalates. However, little is known about the effects of DEHTP on the ovary. In this research, we tested the hypothesis that DEHTP is an ovarian toxicant and likely endocrine disrupting chemical like its isomer DEHP. The impact of environmentally relevant exposure to DEHTP and/or its metabolite mono-2-ethylhexyl terephthalate (MEHTP) on the mouse ovary was investigated in vivo and in vitro. For the in vivo studies, young adult CD-1 mice were orally dosed with vehicle, 10 µg/kg, 100 µg/kg, or 100 mg/kg of DEHTP for 10 days. For the in vitro studies, isolated untreated ovarian follicles were exposed to vehicle, 0.1, 1, 10, or 100 µg/mL of DEHTP or MEHTP. Follicle counts, hormone levels, and gene expression of steroidogenic enzymes, cell cycle regulators, and apoptosis factors were analyzed. In vivo, DEHTP exposure increased primordial follicle counts at 100 µg/kg and 100 mg/kg and decreased primary follicle counts at 100 mg/kg compared to control. DEHTP exposure also decreased expression of cell cycle regulators and apoptotic factors compared to control. In vitro, follicle growth was reduced by 1 µg/mL DEHTP and 1, 10, and 100 µg/mL MEHTP compared to controls, and expression of the cell cycle regulator Cdkn2b was increased. Steroid hormone levels and steroidogenic enzyme gene expression trended toward decreases in vivo, whereas progesterone was significantly increased by exposure to 100 µg/mL MEHTP in vitro. Overall, these results suggest that DEHTP and MEHTP may be ovarian toxicants at low doses and should be subjected to further scrutiny for reproductive toxicity due to their similar structures to phthalates.

Polyvinyl chloride microplastics in the aquatic environment enrich potential pathogenic bacteria and spread antibiotic resistance genes in the fish gut

Microplastics and antibiotics coexist in aquatic environments, especially in freshwater aquaculture areas. However, as the second largest production of polyvinyl chloride (PVC) in the world, the effects of co-exposure to microplastics particles and antibiotics on changes in antibiotic resistance gene (ARG) profiles and the microbial community structure of aquatic organism gut microorganisms are poorly understood. Therefore, in this study, carp (Cyprinus carpio) were exposed to single or combined PVC microplastic contamination and oxytetracycline (OTC) or sulfamethazine (SMZ) for 8 weeks. PVC microplastics can enrich potential pathogenic bacteria, such as Enterobacter and Acinetobacter, among intestinal microorganisms. The presence of PVC microplastics enhanced the selective enrichment and dissemination risk of ARGs. PVC microplastics combined with OTC (OPVC) treatment significantly increased the abundance of tetracycline resistance genes (1.40-fold) compared with that in the OTC exposure treatment, revealing an obvious co-selection effect. However, compared with those in the control group, the total abundance of ARGs and MGEs in the OPVC treatment groups were significantly lower, which was correlated with the reduced abundances of the potential host Enterobacter. Overall, our results emphasized the diffusion and spread of ARGs are more influenced by PVC microplastics than by antibiotics, which may lead to antibiotic resistance in aquaculture.

A Study of Plant-Filled Polymer Composites Based on Highly Plasticized Polyvinyl Chloride.

To enhance the ecological properties of polyvinyl chloride (PVC) products, the fabrication of PVC-based composites using biofillers with acceptable performance characteristics could be considered. In this work, plant-filled PVC-based composite materials were fabricated and their optical, structural, thermal, and mechanical properties, depending on the nature of the filler, were studied. Spruce flour, birch flour, and rice husk were used as fillers. Optical measurements showed the selected technological parameters, allowing films with a uniform distribution of dispersed plant filler in the polymer matrix to be obtained. Using the plant fillers in PVC films leads to a reduction in strength characteristics; for instance, the tensile strength changed from 18.0 MPa (for pure PVC film) to ~7 MPa (for composites with 20 wt.% of fillers), and to ~5-6.2 MPa (for composites with 40 wt.% of fillers). Thermal investigations showed that the samples with plant fillers could be used at low temperatures without changing their operating characteristics. Thus, plant-filled PVC-based composite materials have a wide operating temperature range, from-65 °C to 150 °C. TGA analysis has demonstrated that the rice husk affected the thermal stability of the composites by increasing their thermal decomposition resistance. The ability to absorb water was observed during the investigation of water absorption of the samples. And the highest degree of water absorption (up to 160 mg/g) was detected for the sample with 40 wt.% of rice husk. In general, plant-filled polymer composites based on PVC can be used on an equal basis with unfilled PVC plastic compounds for some applications such as in construction (for example, for design tasks).

The evaluation of skin sensitization potential of the UVCB substance diisopentyl phthalate by in silico and in vitro methods

Diisopentyl phthalate (DiPeP) is primarily used as a plasticizer or additive within the production of polyvinyl chloride (PVC), and has many additional industrial applications. Its metabolites were recently found in urinary samples of pregnant women; thus, this substance is of concern as relates to human exposure. Depending upon the nature of the alcohol used in its synthesis, DiPeP may exist either as a mixture consisting of several branched positional isomers, or as a single defined structure. This article investigates the skin sensitization potential and immunomodulatory effects of DiPeP CAS No. 84777-06-0, which is currently marketed and classified as a UVCB substance, by in silico and in vitro methods. Our findings showed an immunomodulatory effect for DiPeP in LPS-induced THP-1 activation assay (increased CD54 expression). In silico predictions using QSAR TOOLBOX 4.5, ToxTree, and VEGA did not identify DiPeP, in the form of a discrete compound, as a skin sensitizer. The keratinocyte activation (Key Event 2 (KE2) of the adverse outcome pathway (AOP) for skin sensitization) was evaluated by two different test methods (HaCaT assay and RHE assay), and results were discordant. While the HaCaT assay showed that DiPeP can activate keratinocytes (increased levels of IL-6, IL-8, IL-1α, and ILA gene expression), in the RHE assay, DiPeP slightly increased IL-6 release. Although inconclusive for KE2, the role of DiPeP in KE3 (dendritic cell activation) was demonstrated by the increased levels of CD54 and IL-8 and TNF-α in THP-1 cells (THP-1 activation assay). Altogether, findings were inconclusive regarding the skin sensitization potential of the UVCB DiPeP—disagreeing with the results of DiPeP in the form of discrete compound (skin sensitizer by the LLNA assay). Additional studies are needed to elucidate the differences between DiPeP isomer forms, and to better understand the applicability domains of non-animal methods in identifying skin sensitization hazards of UVCB substances.

Designing a sustainable supply chain for battery PVC cases: A multi-objective optimization approach

Nowadays, Polyvinyl Chloride (PVC) and its derivatives are being used in a wide range of products, including car battery cases, due to their corrosion resistance and exceptional durability. As PVC production has grown, the amount of non-hazardous waste generated from PVC products has dramatically increased. In this context, incorporating PVC waste management into the PVC supply chain can effectively address the PVC waste generation issue. This study investigates the design of the Polyvinyl Chloride Closed-Loop Supply Chain (PVCCLSC) based on a triple-objective model for Abadan Petrochemical Company. The first objective aims to minimize the total cost of PVCCLSC, the second objective focuses on minimizing environmental impact, and the third objective maximizes the improvement of Occupational Health and Safety (OHS). In this study, an integrated solution approach is developed encompassing four main phases: (i) Developing an accelerated K-means clustering algorithm, along with the Elbow Method (EM) and Average Silhouette Method (ASM), to estimate the quality of returned PVC products, (ii) Employing a robust optimization method to capture the uncertainty, (iii) Implementing an augmented ε-constraint method to solve the proposed multi-objective model, and (iv) Applying a Bender’s Decomposition Algorithm (BDA) to solve the model and determine optimal solutions. As a result of the proposed BDA, relative optimality gaps have been reduced from 4.56 % in the conventional solution to zeros, and runtime has been reduced from 55 min to 20 min. Furthermore, as a result of this study, more than 44 % of returned PVC products should be recycled using the tertiary method to fulfill environmental requirements.

Utilizing pulverized waste polyvinyl chloride film as an alternative reducing agent for iron ore reduction

The research into using waste plastics as a substitute for coal powder and coke as a reducing agent has garnered significant attention, driven by various factors such as increased environmental concerns and growing interest in sustainable materials. This study investigates the process of carbothermal reduction using a mixture of waste polyvinyl chloride (PVC) and iron concentrate. Thermogravimetric analysis demonstrated that the heat-treated polyvinyl chloride products (PVC370) exhibited superior reaction properties compared to anthracite. Reduction tests indicated that PVC370-bearing pellets were less sensitive to temperature changes than anthracite-bearing pellets, highlighting a potential advantage of PVC370 in industrial applications. Moreover, the metallization ratio of PVC370-bearing pellets exceeded that of anthracite-bearing pellets before reaching 1150 °C. At a temperature of 1100 °C and a C/O of 0.8, the metallization ratio of PVC370-bearing pellets peaked at 83.17 %. During the reduction process of PVC370-bearing pellets, hydrogen (H2), carbon monoxide (CO), and hydrogen chloride (HCl) were efficiently released at relatively low temperatures. The efficiency of gas release in the reduction process could be attributed to certain factors, such as the composition or structure of the PVC370-bearing pellets. Notably, the quality of gasses generated during the reduction process of PVC370-bearing pellets is superior to that of anthracite-bearing pellets, even when considering chlorine content.

Synthesis and application of environmental plasticizers based on benzene polyacid ester

AbstractUsing benzene‐1,3,5‐tricarboxylic acid, trimellitic anhydride, 2‐propylheptanol and 2‐ethylhexanol as raw materials, four kinds of environmental plasticizers were prepared, which were used as additives for polyvinyl chloride (PVC) products. Compared with commercially available di (2‐ethylhexyl) phthalate (DOP), di (2‐ethylhexyl) terephthalate (DOTP), and tributyl citrate (TBC), the application performance and plasticizing performance were compared. The structure of the target product was analyzed by fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy to verify the fingerprint region of the molecular structure of the product. The properties of plasticized PVC films were tested by thermal weight loss analysis, oven thermal aging test, migration and volatility resistance test, DMA analysis, and scanning electron microscopy. The plasticizing mechanism was confirmed through quantum chemical calculations, and the results of the calculations were in line with the migration outcomes. The results showed that compared with commercially available plasticizers, benzene polyacid ester plasticizers had better thermal stability, and better cold resistance in the polar environments, suitable for high‐temperature and water‐based environments.Highlights The four plasticizers prepared in this study were compared with reference plasticizers, and the plasticizing mechanism was validated through quantum chemical calculations. The PVC film plasticized with benzene polyacid ester prepared in this study demonstrates outstanding thermal stability, surpassing certain plasticizers reported in current literature. Benzene polyacid esters plasticized PVC film has migration stability under various conditions, it has great potential in packaging and other applications.

Comprehensive investigation of recycled PVC powder.

This study constitutes a comprehensive investigation centred on comprehending the behaviour and characteristics of recycled polyvinyl chloride (PVC) powders. The overarching objective is to successfully conclude the initial research phase, during which PVC-coated fabric offcuts undergo a transformation into PVC powder while achieving complete separation from polyethylene terephthalate fibres. The study entails a qualitative description of the morphology of PVC powder particles, employing an optical microscope to distinguish the diverse shapes exhibited by these particles. The optical microscope observations of PVC powder reveal a distinct array of non-spherical particles characterized by flat, elongated shapes. These high-magnification images unveil the intricate morphological features of the particles, highlighting their irregular shapes. Subsequently, a quantitative analysis of PVC particle size distribution is performed, comparing results from optical microscopy with those obtained through mechanical sieving. The qualitative and quantitative findings obtained provide robust evidence supporting the correlation and confirm that most particles are smaller than 600 µm (93.6%) using an optical microscope and the sieving process (96.39%). The greatest fraction (83.44%) is in the size range between 200 and 600 µm. Assessing flowability, another significant aspect in the evaluation of powders, provides insights into its behaviour and interparticle interactions. The flowability results indicate a Compressibility Index of approximately 26.84%, which suggests poor flowability. This means that the powder is likely to encounter difficulties in flowing freely. This finding is in line with the Hausner ratio, which measures 1.37. This investigation of recycled PVC powder will offer insights into the potential applications and processing considerations of this powder. More concretely, the use of recycled PVC powder shows promise as a viable alternative to conventional PVC resin in plastisol formulations, offering the potential to maintain the properties of the final PVC product without adverse effects.

Beyond the Nucleus: Plastic Chemicals Activate G Protein-Coupled Receptors.

G protein-coupled receptors (GPCRs) are central mediators of cell signaling and physiological function. Despite their biological significance, GPCRs have not been widely studied in the field of toxicology. Herein, we investigated these receptors as novel targets of plastic chemicals using a high-throughput drug screening assay with 126 human non-olfactory GPCRs. In a first-pass screen, we tested the activity of triphenol phosphate, bisphenol A, and diethyl phthalate, as well as three real-world mixtures of chemicals extracted from plastic food packaging covering all major polymer types. We found 11 GPCR-chemical interactions, of which the chemical mixtures exhibited the most robust activity at adenosine receptor 1 (ADORA1) and melatonin receptor 1 (MTNR1A). We further confirm that polyvinyl chloride and polyurethane products contain ADORA1 or MTNRA1 agonists using a confirmatory secondary screen and pharmacological knockdown experiments. Finally, an analysis of the associated gene ontology terms suggests that ADORA1 and MTNR1A activation may be linked to downstream effects on circadian and metabolic processes. This work highlights that signaling disruption caused by plastic chemicals is broader than that previously believed and demonstrates the relevance of nongenomic pathways, which have, thus far, remained unexplored.

Revealing the long way towards lead-free plastic in China through dynamic material flow analysis of lead salt heat stabilizers in PVC products

The use of lead salt heat stabilizers (LHSs) in plastics are restricted or even prohibited owing to their high toxicity. However, little information is available on its industrial metabolism. A dynamic material flow analysis of LHSs indicates that China consumed 2952 kt LHSs between 1958 and 2020. Moreover, at present, 1020 kt of these is being used in polyvinyl chloride (PVC) products, 1007 kt is in landfills, and 681 kt is in the environment. For China to realize lead-free primary plastics by 2040, 2050, and 2060, the LHSs consumption should be reduced by at least 13 %, 10 %, and 9 % annually, respectively. Certain LHSs would gain new life with PVC recycling. Therefore, approximately 30 years would be required for LHSs to disappear completely after their use is stopped. With improvements in the plastic recycling rate, it is necessary to use chemical recycling and other methods to separate the hazardous additives such as LHSs and reduce the circulation of toxic substances.

Evaluation of Bis(2-ethylhexyl) phthalate toxicity on the third instar larvae of transgenic Drosophila melanogaster (hsp70-lacZ) Bg9

Bis(2-ethylhexyl) phthalate, generally known as DEHP is a synthetic compound mainly used as a plasticizer to make polyvinyl chloride products flexible and soft. The present work aimed to study the toxicity of Bis(2-ethylhexyl) phthalate on the third instar larvae of transgenic Drosophila melanogaster(hsp70-lacZ) Bg9. The hsp70 gene is associated with the β-galactosidase in our present transgenic strain therefore, the more activity of β-galactosidase will indirectly correspond to hsp70 expression. The third instar larvae were allowed to feed on the diet for 24 h having 0.001, 0.005, 0.01, and 0.02 M of Bis(2-ethylhexyl) phthalate at the final concentration. After the exposure of 24hrs, the larvae were subjected to ONPG assay, X-gal staining, trypan blue exclusion test, oxidative stress markers assays, and comet assay. A dose-dependent increase in hsp70 expression, tissue damage, Glutathione-S-transferase (GST) activity, lipid peroxidation, monoamine oxidase, caspase-9 & 3, protein carbonyl content (PCC), DNA damage and decrease in the glutathione (GSH) content, delta-aminolevulinic acid dehydrogenase (ẟ-ALD-D) and acetylcholinesterase activity were observed in the larvae exposed to 0.005, 0.01, 0.02 M of Bis-(2-ethylhexyl) phthalate. The dose of 0.001 M of Bis(2-ethylhexyl) phthalate did not showed any toxic effects and hence can be considered as No Observed Adverse Effect Level (NOAEL) for Bis(2-ethylhexyl) phthalate. The study supports the use of Drosophila for the evaluation of possible toxic effects associated with synthetic compounds.

Induction of Caspase-dependent Apoptosis in Rat Bone Marrow Mesenchymal Stem Cells Due to Di-2-Ethylhexyl Phthalate Toxicity was Found to Arrest the Cell Cycle at the G1 Stage.

Di-(2-ethylhexyl) phthalate (DEHP) is used as a plasticizer in polyvinyl chloride products which is widely utilized. Previously we found, DEHP reduced the viability and proliferation ability of bone marrow mesenchymal stem cells (BMSCs). In the present study, the mechanism of DEHP toxicity was investigated. Rat BMSCs were cultured up to 3rd passage and their viability was determined after treatment with 100 and 500 μM of DEHP for 24 and 48 hours. The levels of sodium, potassium, and calcium as well as induction of apoptosis were investigated. Using flow cytometry, cell cycle analysis was performed and the expression of genes involved in the cell cycle was evaluated using reverse transcriptase-PCR. Data were analyzed and p < 0.05 was taken as the level of significance. Although the viability and electrolyte level of BMSCs were not affected with 100 μM of DEHP, this environmental pollution induced caspase-dependent apoptosis in a concentration-dependent manner. In both of the concentrations, DEHP arrests the cell cycle at the G0/G1 phase, and the expression of Cdk2 and Cdk4 was significantly reduced whereas an over-expression of P53 was observed. However, the expression of the raf1 gene remained unchanged. DEHP induces caspase-dependent apoptosis in BMSCs and arrests the cell cycle due to the reduction of Cdk2 and Cdk4 expression via over-expression of P53.

Bibliometric and Co-Occurrence Study of Process System Engineering (PSE) Applied to the Polyvinyl Chloride (PVC) Production.

PVC is widely used in packaging, electrical insulation, and medical devices due to its versatility owing to its resistance, incombustible and barrier properties as well as affordable cost. In the present study, bibliometric and co-occurrence analyses are proposed to identify trends, gaps, future directions, and challenges regarding process system engineering (PSE) applied to the production process of PVC using VOSviewer as a tool for analyzing the data obtained from SCOPUS. A mapping of different topics alluding to simulation of PVC production was provided to gain a better insight into the development of the topic and its progression. The findings indicate that the literature on this topic falls into five different clusters: modeling and simulation of PVC production, process control and optimization, and optimization strategies of the process. From a co-occurrence study we identified that mathematics and statistics applied to polymer chemistry, separation phenomena, and polymer production are the main areas of interest for further research. The trends suggest that Monte Carlo and numerical simulation can contribute to a deeper understanding of PVC's properties and behavior. In addition, the focus on plastics and microplastics reflects concerns about the environmental impact. A bibliometric study evidenced that PSE provides the tools for improvement in PVC production processes by employing advanced process engineering techniques. Modelling and new algorithms for simulation methods of continuous polymerization processes are important to enhance accuracy and efficiency across various applications. The study also proposes a research agenda for future researchers working in the field of the use of PSE applied to the PVC production process.

Accurate determination of 11 representative phthalates and di(2-ethylhexyl) terephthalate in polyvinyl chloride using isotope dilution-gas chromatography/mass spectrometry

Phthalates are mainly used as plasticizers in polyvinyl chloride (PVC). However, prolonged exposure to phthalates poses considerable risks to human health. Consequently, the utilization of phthalates in consumer products is subject to regulations, with a defined threshold of 0.1 %. In this study, we developed an accurate and simultaneous method for determination of 11 representative phthalates and a non-phthalate plasticizer (di(2-ethylhexyl) terephthalate, DEHT) in PVC as a higher-order reference method. Homogeneously prepared PVC samples, each containing approximately 0.1 % of the target plasticizer compounds, were analyzed using gas chromatography-mass spectrometry (GC–MS) with deuterium-labeled phthalates and DEHT. The developed method could effectively separate and quantify all target plasticizers without interference with each other and potential overlap between the isomeric forms of phthalates, di-isodecyl phthalate, and di-isononyl phthalate. The developed method has high-order metrological quality, exhibiting exceptional selectivity, accuracy, repeatability (≤ 2.17 %), reproducibility (≤ 2.16 %), and relative expanded uncertainty (≤ 5.6 %). This analytical method is thus suitable for accurately assessing the target plasticizer levels in PVC products for ensuring compliance with the established 0.1 % threshold. This method was successfully applied to quantify twelve distinct plasticizers in PVC products obtained from the Korean market, validating its effectiveness and reliability in real-world scenarios.

The effects of short-term and long-term phthalate exposures on ovarian follicle growth dynamics and hormone levels in female mice†.

Di(2-ethylhexyl) phthalate and diisononyl phthalate are widely used as plasticizers in polyvinyl chloride products. Short-term exposures to phthalates affect hormone levels, ovarian follicle populations, and ovarian gene expression. However, limited data exist regarding the effects of long-term exposure to phthalates on reproductive functions. Thus, this study tested the hypothesis that short-term and long-term exposure to di(2-ethylhexyl) phthalate or diisononyl phthalate disrupts follicle dynamics, ovarian and pituitary gene expression, and hormone levels in female mice. Adult CD-1 female mice were exposed to vehicle, di(2-ethylhexyl) phthalate, or diisononyl phthalate (0.15ppm, 1.5ppm, or 1500ppm) via the chow for 1 or 6months. Short-term exposure to di(2-ethylhexyl) phthalate (0.15ppm) and diisononyl phthalate (1.5ppm) decreased serum follicle-stimulating hormone levels compared to control. Long-term exposure to di(2-ethylhexyl) phthalate and diisononyl phthalate (1500 ppm) increased the percentage of primordial follicles and decreased the percentages of preantral and antral follicles compared to control. Both phthalates increased follicle-stimulating hormone levels (di(2-ethylhexyl) phthalate at 1500ppm; diisononyl phthalate at 1.5ppm) and decreased luteinizing hormone levels (di(2-ethylhexyl) phthalate at 0.15 and 1.5ppm; diisononyl phthalate at 1.5ppm and 1500ppm) compared to control. Furthermore, both phthalates altered the expression of pituitary gonadotropin subunit genes (Cga, Fshb, and Lhb) and a transcription factor (Nr5a1) that regulates gonadotropin synthesis. These data indicate that long-term exposure to di(2-ethylhexyl) phthalate and diisononyl phthalate alters follicle growth dynamics in the ovary and the expression of gonadotropin subunit genes in the pituitary and consequently luteinizing hormone and follicle-stimulating hormone synthesis.

Efficient continuous-flow synthesis of diacyl peroxide in a microreactor and the post-processing of its effluent

Di-(3,5,5-trimethylhexanoyl) peroxide (TMHP) is a low-temperature diacyl peroxide in liquid form, which is widely used as an initiator for the polymerization of vinyl monomers, especially for the production of polyvinyl chloride by suspension polymerization. However, the high reaction heat and the extreme instability of the product of the peroxidation reaction to synthesize TMHP often lead to safety concerns, therefore, the batch reaction processes often sacrifice efficiency in return for better safety. In this work, continuous-flow microreaction technology is utilized to realize an efficient and safe synthesis of TMHP. Under the conditions of T2 = 30°C, NaOH eq. = 1.05, and H2O2 eq. = 1.20, 94% yield could be obtained within 2.80 min, while batch reactors require hours to perform the same yield. It proves that, compared with batch processes, the efficiency is significantly improved by microreaction technology. Besides, a post-processing method for microreactor effluent is also proposed. After four post-processing steps of aging, washing, drying, and formulation, commercial TMHP product could finally be obtained. This work first reports the efficient and safe synthesis of TMHP based on microreaction technology and a post-processing method for microreactor effluent, which not only develops an efficient route from raw material to TMHP commercial products but also provides a basis for the process development of synthesizing other similar organic peroxides in a more efficient and safer manner.

Environmental Impacts Assessment in Suspension PVC Production Process Using Computer-Aided Process Engineering

The new demands for sustainable operation in the chemical industry due to increasing environmental regulations and agreements have generated the need to adapt existing processes to more intelligent production. The plastics sector is in a complex position due to its contribution to economic development and the climate crisis. Therefore, environmental assessment has become an important tool due to the benefits it provides by quantifying the environmental performance of processes, allowing it to balance operational and environmental needs. Polyvinyl chloride (PVC) is one of the most globally used polymers thanks to its resistance, flexibility, and cost-effectiveness. The polymer is synthetized by suspension polymerization, which is characterized by high productivity and controllability. However, it presents problems associated with intensive energy consumption and the emission of toxic substances and greenhouse gases. Therefore, an environmental assessment of the suspension PVC production process was performed using the waste reduction algorithm (WAR). The potential environmental impact (PEI) was quantified using the generation rate and the output velocity for four cases and three different fuels. It was found that the process transforms raw materials with high impacts, such as VCM, into substances with lower PEI, such as PVC. However, the process has a high generation of PEI due to the effects of energy consumption (−2860, −2410, 3020, and 3410 for cases 1–4, respectively). The evaluation of the toxicological impacts shows that the ATP category is the only one that presents a positive generation value (75 PEI/day); the product contributes to the formation and emission of impacts. The atmospheric categories showed that the energy consumption of the process is the most critical aspect with a contribution of 91% of the total impacts emitted. The AP and GWP categories presented the highest values. It was determined that the most suitable fuel is natural gas; it has lower impacts than liquid and solid fuels (coal). Additionally, it can be concluded that the PVC production process by suspension is environmentally acceptable compared to the polyethylene or polypropylene processes, with output impacts 228 and 2561 times lower, respectively.