Ethylene Production Research Articles

Extension of guava shelf life through the application of edible coating formulated with mango and lemon leaves extracts

Innovative green encapsulation techniques using natural plant bioactives provide a sustainable method for extending the shelf life of fruits. Given the inherent perishability of climacteric fruits like guava, characterized by accelerated respiration and ethylene production during ripening, our study is planned to explore the efficacy of incorporating leaf extracts of Mangifera indica L. and Citrus limon L. in combination with Gum Arabic (GA) for bioactive encapsulation of guava fruits. Response surface methodology (RSM) was used and a total of 15 experimental runs were set. Mango leaf extract (MLE) and lemon leaf extract (LLE) were employed at concentrations ranging from 500 to 2000 mg/L, while Gum Arabic (GA) was utilized in concentration ranging from 5% to 15%. The concentrations of MLE, LLE and GA were stored at 10±1 °C and 40–45% relative humidity for further usage. The selected analysis like total chlorophyll, and carotenoid content, ascorbic acid content, total phenolic content, total flavonoid content, and antioxidant activity are chosen as responses. Central experimental runs like R2, R11 and R14 (1250 mg/L MLE, 1250 mg/L LLE and 10% GA) remained effective in terms of physical appearance and quality of guava. At the same time, R1 (2000 mg/L MLE, 1250 mg/L, and 15% GA), R7 (500 mg/L MLE, 1250 mg/L LLE and 15% GA), R13 (2000 mg/L MLE, 500 mg/L, and 10% GA) and R15 (1250 mg/L MLE, 2000 mg/L LLE and 5% GA) were not effective at preserving the fruit quality as compared to other treatments. The control is below in all quality attributes as compared to all fifteen treatments. It is concluded that the combined impact of MLE and LLE along with GA had good potential for preserving guava fruits for longer period as compared to control, where no treatment was given.

High yield electrosynthesis of oxygenates from CO using a relay Cu-Ag co-catalyst system

As a sustainable alternative to fossil fuel-based manufacture of bulk oxygenates, electrochemical synthesis using CO and H2O as raw materials at ambient conditions offers immense appeal. However, the upscaling of the electrosynthesis of oxygenates encounters kinetic bottlenecks arising from the competing hydrogen evolution reaction with the selective production of ethylene. Herein, a catalytic relay system that can perform in tandem CO capture, activation, intermediate transfer and enrichment on a Cu-Ag composite catalyst is used for attaining high yield CO-to-oxygenates electrosynthesis at high current densities. The composite catalyst Cu/30Ag (molar ratio of Cu to Ag is 7:3) enables high efficiency CO-to-oxygenates conversion, attaining a maximum partial current density for oxygenates of 800 mA cm−2 at an applied current density of 1200 mA cm−2, and with 67 % selectivity. The ability to finely control the production of ethylene and oxygenates highlights the principle of efficient catalyst design based on the relay mechanism.

Towards carbon neutrality: Transition pathways for the Chinese ethylene industry

Ethylene is one of the most important products in the emissions-intensive petrochemical industry. Decarbonizing the ethylene industry is thus important for achieving global carbon neutrality. This study is the first to explore future long-term zero-emissions production pathways for the ethylene industry in China, the world's biggest ethylene producer. An optimization model was built in the context of China's carbon neutrality target of 2060. Four scenarios were developed where the policy ambitions for climate mitigation and for plastic management including waste were varied. Based on this, authors assessed the cumulative total emissions, technology options, future geographical location of ethylene production, and policy challenges associated with each scenario. This is also the first time that scope 3 emissions from waste incineration are included, motivated by the short lifetime of most ethylene products. Results show the cumulative CO2 emissions for the scenarios differ considerably, ranging from 4.3 to 7.8 Gt, even if carbon neutrality by 2060 is achieved in all scenarios. The results suggest that ambitious plastic focused policies can result in lower costs and less cumulative emissions compared to ambitious climate focused policies. The results demonstrate the importance of adopting CCS for waste incineration. This reduces cumulative CO2 emissions by up to 2 Gt. However, reduced overall demand and increased recycling rates should be priority options due to CCS challenges. Results suggest Chinese ethylene industry should adopt a mixed portfolio of production technologies, where the share of emission-intensive coal-based methanol-to-olefins is limited. These findings on decarbonization pathways can contribute to achieving the Paris agreement.

Kinetic Studies of Liquid Phase Hydrogenation of Acetylene for Ethylene Production Using a Selective Solvent over a Commercial Palladium/Alumina Catalyst

Kinetic Studies of Liquid Phase Hydrogenation of Acetylene for Ethylene Production Using a Selective Solvent over a Commercial Palladium/Alumina Catalyst

Techno-Economic Analysis of Dimethyl Ether Production from Different Biomass Resources and Off-Grid Renewable Electricity

Techno-Economic Analysis of Dimethyl Ether Production from Different Biomass Resources and Off-Grid Renewable Electricity

Regulating Spin Density using TEMPOL Molecules for Enhanced CO2-to-Ethylene Conversion by HKUST-1 Framework Derived Electrocatalysts.

The selectivity of multicarbon products in the CO2 reduction reaction (CO2RR) depends on the spin alignment of neighboring active sites, which requires a spin catalyst that facilitates electron transfer with antiparallel spins for enhanced C-C coupling. Here, we design a radical-contained spin catalyst (TEMPOL@HKUST-1) to enhance CO2-to-ethylene conversion, in which spin-disordered (SDO) and spin-ordered (SO) phases co-exist to construct an asymmetric spin configuration of neighboring active sites. The replacement of axially coordinated H2O molecules with TEMPOL radicals introduces spin-spin interactions among the Cu(II) centers to form localized SO phases within the original H2O-mediated SDO phases. Therefore, TEMPOL@HKUST-1 derived catalyst exhibited an approximately two-fold enhancement in ethylene selectivity during the CO2RR at -1.8 V versus Ag/AgCl compared to pristine HKUST-1. In situ ATR-SEIRAS spectra indicate that the spin configuration at asymmetric SO/SDO sites significantly reduces the kinetic barrier for *CO intermediate dimerization toward the ethylene product. The performance of the spin catalyst is further improved by spin alignment under a magnetic field, resulting in a maximum ethylene selectivity of more than 50%. The exploration of the spin-polarized kinetics of the CO2RR provides a promising path for the development of novel spin electrocatalysts with superior performance.

Bottom‐up Growth of Convex Sphere with Adjustable Cu(0)/Cu(I) Interfaces for Effective C2 Production from CO2 Electroreduction

One challenge confronting the Cu2O catalysts in the electrocatalysis of carbon dioxide reduction reaction (CO2RR) is the reduction of active Cu(I) species, resulting in low selectivity and quick deactivation. In this study, we for the first time introduce a bottom‐up growth of convex sphere with adjustable Cu(0)/Cu(I) interfaces (Cux@Cu2O convex spheres). Interestingly, the interfaces are dynamically modulated by varying hydrothermal time, thus regulating the conversion of C1 and C2 products. In particular, the 4 h hydrothermal treatment applied to Cu0.25@Cu2O convex sphere with the favorable Cu(0)/Cu(I) interface results in the highest selectivity for C2 products (90.5%). In situ Fourier‐transform infrared spectroscopy measurements and density functional theory calculations reveal that the Cu(0)/Cu(I) interface lowers the energy barrier for the production of ethylene and ethanol while increasing the coverage of localized *CO adsorbate for increased dimerization. This work establishes a novel approach for transforming the state of valence‐sensitive electrocatalysts into high‐value energy‐related engineering products.

Bottom-up Growth of Convex Sphere with Adjustable Cu(0)/Cu(I) Interfaces for Effective C2 Production from CO2 Electroreduction.

One challenge confronting the Cu2O catalysts in the electrocatalysis of carbon dioxide reduction reaction (CO2RR) is the reduction of active Cu(I) species, resulting in low selectivity and quick deactivation. In this study, we for the first time introduce a bottom-up growth of convex sphere with adjustable Cu(0)/Cu(I) interfaces (Cux@Cu2O convex spheres). Interestingly, the interfaces are dynamically modulated by varying hydrothermal time, thus regulating the conversion of C1 and C2 products. In particular, the 4 h hydrothermal treatment applied to Cu0.25@Cu2O convex sphere with the favorable Cu(0)/Cu(I) interface results in the highest selectivity for C2 products (90.5%). In situ Fourier-transform infrared spectroscopy measurements and density functional theory calculations reveal that the Cu(0)/Cu(I) interface lowers the energy barrier for the production of ethylene and ethanol while increasing the coverage of localized *CO adsorbate for increased dimerization. This work establishes a novel approach for transforming the state of valence-sensitive electrocatalysts into high-value energy-related engineering products.

Visible-light-mediated O–H functionalization reactions of acetylenic alcohols with 3-diazooxindoles: Facile access to spirooxindole-fused oxacycles

Visible-light-mediated O–H functionalization reactions of acetylenic alcohols with 3-diazooxindoles were first described. Various substituted acetylenic alcohols were well tolerated and the O–H functionalization products were delivered in moderate to high yields. More importantly, these ether products could be easily transformed into spirooxindole-fused oxacycles. A preliminary study of the mechanism revealed that this reaction probably proceeded through a carbene transfer instead of a proton transfer pathway.

Rats Orally Administered with Ethyl Alcohol for a Prolonged Time Show Histopathology of the Epididymis and Seminal Vesicle Together with Changes in the Luminal Metabolite Composition

Prolonged ethanol (EtOH) consumption is associated with male infertility, with a decreased spermatogenesis rate as one cause. The defective maturation and development of sperm during their storage in the cauda epididymis and transit in the seminal vesicle can be another cause, possibly occurring before the drastic spermatogenesis disruption. Herein, we demonstrated that the cauda epididymis and seminal vesicle of rats, orally administered with EtOH under a regimen in which spermatogenesis was still ongoing, showed histological damage, including lesions, a decreased height of the epithelial cells and increased collagen fibers in the muscle layer, which implicated fibrosis. Lipid peroxidation (shown by malondialdehyde (MDA) levels) was observed, indicating that reactive oxygen species (ROS) were produced along with acetaldehyde during EtOH metabolism by CYP2E1. MDA, acetaldehyde and other lipid peroxidation products could further damage cellular components of the cauda epididymis and seminal vesicle, and this was supported by increased apoptosis (shown by a TUNEL assay and caspase 9/caspase 3 expression) in these two tissues of EtOH-treated rats. Consequently, the functionality of the cauda epididymis and seminal vesicle in EtOH-treated rats was impaired, as demonstrated by a decreases in 1H NMR-analyzed metabolites (e.g., carnitine, fructose), which were important for sperm development, metabolism and survival in their lumen.

Hydrogen sulfide inhibits tomato fruit ripening by restraining fruit softening and ethylene production

Hydrogen sulfide (H2S) plays various roles in plant growth, development and stress response. However, the mechanism of action of H2S in fruit ripening remains unclear. This study investigated the roles and mechanisms of H2S in tomato (Solanum lycopersicum) fruit repining. The results showed that compared with the control (distilled water), H2S treatment significantly delayed the color and hardness transition of tomato fruit; while an H2S scavenger hypotaurine (HT) treatment promoted the color and hardness transition. H2S increased the endogenous chlorophyll content, activity of chlorophyll synthesis-related enzymes, and expression of chlorophyll synthesis-related genes and decreased the expression of chlorophyll degradation-related genes and lycopene content. In contrast, HT decreased the activity of chlorophyll synthesis-related enzymes and expression of related genes; and increased the expression of chlorophyll degradation-related genes. In addition, the activity of the softening-related enzymes, ACS and ACO, ethylene content, and the expression of softening- and ethylene biosynthesis-related genes were decreased by H2S but increased by HT. Exogenous H2S increases endogenous H2S levels. Therefore, H2S may delay tomato fruit ripening by down-regulating the expression of softening-related and ethylene synthesis-related genes and reducing the activity of softening-related and ethylene synthesis-related enzymes.

Continuous Production of Ethylene and Hydrogen Peroxide from Paired Electrochemical Carbon Dioxide Reduction and Water Oxidation (Adv. Energy Mater. 18/2024)

Continuous Production of Ethylene and Hydrogen Peroxide from Paired Electrochemical Carbon Dioxide Reduction and Water Oxidation (Adv. Energy Mater. 18/2024)

Variability of fruit shelf-life of commercial tomatoes and their hybrids crossing with insensitivity ethylene mutant tomato Sletr1-2

Tomatoes are climacteric fruits that experience a surge in respiration rate and ethylene production. This condition affects the fruits’ physiological deterioration, shortens their shelf-life, and degrades the quality of tomatoes. The study aimed to enhance the shelf-life of commercial tomatoes with different genetic backgrounds by utilizing the Sletr1-2 mutant, which has a lower sensitivity to ethylene. A randomized block design (RBD) was applied to achieve this goal, where 12 different plant genotypes were considered as treatments, and each treatment was replicated four times.  The results showed that fruit shelf-life was extended by crossing commercial tomatoes with Sletr1-2 mutant tomatoes. Genetic variability for all shelf-life characteristics were narrow. In contrast, there were broad phenotypic variability for fruit hardness and weight loss characteristics.

Unlocking waste potential: A neural network approach to forecasting sustainable acetaldehyde production from ethanol upcycling in biomass waste gasification

The upcycling of biomass waste gasification process for ethanol and acetaldehyde production has been augmented by integrating secondary and tertiary processes. A simulation model using Aspen Plus, developed from experimental investigations to assess the viability of this proposed system. Furthermore, this model has been utilized to create an Artificial Neural Network (ANN) prediction model. Process sustainability analysis demonstrated an energy efficiency of 64 % while economic viability up to 80 % process efficiency with an Internal Rate of Return (IRR) of 6 % and a payback period of 2107 days. An optimization strategy and an artificial neural network (ANN)-based predictive model have been developed. Optimization results revealed that a gasifier temperature of around 600 °C, a gasifying agent ratio of 2.0, and an acetaldehyde reactor temperature of 300 °C yield better process outcomes and revenue. The ANN model exhibited robust performance with coefficient of determination (R2) values ranging from 0.92 to 0.98 for acetaldehyde, hydrogen, and total revenue. Mean absolute error (MAE) and mean absolute percentage error (MAPE) fell within the range of 0.03–0.1 and 0.1–1.12 %, respectively. Consequently, given the favorable sustainability and predictive model performance, this study can be used for similar endeavors.

One-Step Ethanol Conversion for 1,3-Butadiene Synthesis over Two-Dimensional VMT-SiO2 Nanomesh Loaded with Magnesium and Copper Oxide

A two-dimensional porous silica nanomesh (VMT-SiO2) was used as a carrier to prepare MgO-CuO-based catalysts and tested for one-step ethanol conversion to 1,3-butadiene. The effects of catalyst composition and different calcination temperatures on the reaction performances of the catalysts were mainly investigated. Combining various characterization techniques, such as HRTEM, XRD, FT-IR, and TPD, it was found that the dispersion state of MgO and CuO on the catalyst surface was related to the calcination temperature, which further induced changes in the acid–base properties. A small number of acidic centers and a proper proportion of medium–strong alkaline centers maintained a subtle balance, affecting catalytic performance. A lower total acid/base ratio is more conducive to ethanol conversion and 1,3-butadiene formation. At the same time, the synergistic effect of CuO and MgO promotes the transformation of the intermediate acetaldehyde product, which is the key to ensuring the subsequent aldol condensation and then 1,3-butadiene formation. Among the investigated samples, the CuO/MgO-VMT-SiO2 catalyst calcined at 500 °C exhibited the best catalytic performance, with an impressive ethanol conversion of 47.8% and 1,3-butadiene formation (42.6% selectivity and a space-time yield of 182.0 gC4H6·kgcat−1·h−1).

Ethylene induced AcNAC3 and AcNAC4 take part in ethylene synthesis through mediating AcACO1 during kiwifruit (Actinidia chinensis) ripening.

Ethylene plays a vital role in the ripening process of kiwifruit. A terrific amount of transcription factors (TFs) have been shown to regulate ethylene synthesis in various fruits. In this research, two new NAC TFs, named AcNAC3 and AcNAC4, were isolated from kiwifruit, which belonged to NAM subfamily. Bioinformatics analysis showed that both AcNAC3 and AcNAC4 were hydrophilic proteins with similar three-dimensional structures. The expression levels of AcNAC3, AcNAC4 and AcACO1 increased during kiwifruit ripening, as well as were induced by ethylene and repressed by 1-methylcyclopropene (1-MCP). Correlation analysis exhibited that ethylene production was positively correlated with the expression levels of AcNAC3, AcNAC4 and AcACO1. Moreover, both AcNAC3 and AcNAC4 acted as transcriptional activators and could bind to and activate AcACO1 promoter. All results unveiled that the ethylene-induced AcNAC3 and AcNAC4 were transcriptional activators, and might participate in kiwifruit ripening and ethylene biosynthesis through activating AcACO1, providing a new insight of ethylene synthetic regulation during kiwifruit ripening. © 2024 Society of Chemical Industry.

[Visualization of mitochondrial dynamics in tomato based on green fluorescent protein].

This study aimed to visualize the morphological features and dynamic changes of tomato mitochondria to provide a basis for the study of its mitochondrial functions. In this study, transgenic tomatoes expressing mitochondria-localized green fluorescent protein (mitochondria-GFP, Mt-GFP) were obtained by Agrobacterium-mediated genetic transformation. The color, hardness, soluble solids, acidity content, respiration rate, and ethylene production of the transgenic Mt-GFP tomato fruits were determined at the stage of mature green, breaker, and 3, 6, 9 days after breaker, while the wild-type tomato fruits were used as a control. As expected, Mt-GFP recombinant protein did not affect the ripening process, but induced the increased acidity of tomato fruits. The accumulations of Mt-GFP protein in tomato leaves and fruits were successfully verified by Western blotting. The morphological characteristics of mitochondria in flower, leaf and fruit cells as well as the dynamic changes of mitochondria in flower cells were clearly observed and studied under confocal laser microscope. The development of transgenic Mt-GFP tomato plants helps the visualization of tomato mitochondria and provides good research materials for the study of mitochondrial function during tomato development and fruit ripening.

Experimental Combustion and Flame Characterization of a Chemical Looping Based Oxidative Dehydrogenation Byproduct Fuel Mixture Containing High CO2 Dilution

Abstract This study investigates the combustion performance of CO2 rich fuel mixtures containing ethane and methane as active species using a constant volume combustion chamber. This fuel is obtained as byproducts of a chemical looping based oxidative dehydrogenation (Cl-ODH) process ethylene production. The byproduct gas mixture has 40.79% CO2, 39.49% ethane, and 4.88% methane by weight with other minor compounds. After initial combustion modelling, the gas fuel mixture was reduced to just the major species: CO2, ethane, and methane. The mixture was then tested for flammability limits and combustion performance under spark-ignition conditions. Effects of ambient conditions and stoichiometry like temperatures between 300 to 400 K with initial pressures from 1 to 10 bar were tested. The fuel mixture showed an overall reduced flame velocity compared to gasoline. Instability in combustion was believed to be caused by the dissociation of ethane under elevated conditions. At higher pressures, the flame produces lower cumulative heat release. Simulations were also performed using a model tuned to replicate the operations of the combustion chamber used in the experiments. Heat release and unburnt fuel mass data were calculated to identify the discrepancies in the combustion completeness at elevated pressures. The effects of CO2 quenching the flame coupled with the increased dissociation of the fuel species can lead to up to more than 75% of the fuel mixture being unburnt. Data from this study was used to modify a small-scale spark-ignition engine to use this fuel and produce usable energy.

CuCl2/FeCl3 Bimetallic Photocatalyst for Sustainable Ethylene Production from Ethanol via Recoverable Redox Cycles.

Photocatalytic conversions of ethanol to valuable chemicals are significant organic synthesis reactions. Herein, we developed a CuCl2/FeCl3 bimetallic photocatalyst for sustainable dehydration of ethanol to ethylene by recoverable redox cycles. The selectivity of ethylene was 98.3% for CuCl2/FeCl3, which is much higher than that of CuCl2 (34.5%) and FeCl3 (86.5%). Due to the ligand-to-metal charge transfer (LMCT) process involved in generating the liquid products, the CuCl2/FeCl3 catalyst will be reduced to CuCl/FeCl2. Oxygen (O2) is required for the recovery of CuCl2/FeCl3 to avoid exhaustion. The soluble Fe3+/Fe2+ redox species deliver catalyst regeneration properties more efficiently than single metal couples, making a series of redox reactions (Cu2+/Cu+, Fe3+/Fe2+, and O2/ethanol couples) recyclable with synergistic effects. A flow reactor was designed to facilitate the continuous production of ethylene. The understanding of bimetallic synergism and consecutive reactions promotes the industrial application process of photocatalytic organic reactions.

Amplicon sequencing and shotgun metagenomics reveal functional impacts of aminoethoxyvinylglycine-mediated ripening and cold storage on the microbiome of ‘NY1’ apples

Understanding community-level microbial dynamics provides more holistic insight into the nature of pathogen infection and biocontrol in fruits and vegetables. We investigated the impact of preharvest sprays of aminoethoxyvinylglycine (AVG, 0.25 g L−1), an inhibitor of ethylene production of fruit, to assess the association between ethylene-mediated ripening and the microbiome at harvest and during storage. ‘NY1’ (Snapdragon®) apples were sprayed on the tree two weeks before first harvest and the microbiome of the fruit was assessed at harvest and at one-week intervals across four weeks. Fruit from harvests 1 and 4 were stored in air at 3 °C for up to 6 months. The bacterial communities changed over harvest time while fungal communities were affected by AVG treatment. In addition, both harvest time and AVG, as well as storage time, were associated with bacterial and fungal variation after 2–6 months of storage. Postharvest fungal microbiomes showed consistent responses to variations in fruit maturation, with the microbial communities of AVG-treated apples being similar to those of early harvested apples. Fungal microbiome variation was linked to the soluble solids concentration and IAD, revealing further links between microbial dynamics and apple quality. Bacterial shifts that occurred from harvest to 6 months of storage were characterized by metagenome changes that resulted in a lower abundance of biofilm formation pathways after cold storage, which may limit the ability of these bacterial communities to block colonization by fungal pathogens. These findings advance our understanding of how the microbiome is connected to fruit quality and functional metagenomics related to biocontrol.