Unwanted By-products Research Articles

Unexpected Emergence of Carbon-Centered Radicals from Piezoelectric Effect in Oleic Acid-Capped BaTiO3.

The utilization of alkyl radicals (•R) for hypoxic tumor therapy has great prospects due to its O2-independence and high reactivity. However, correlational initiators for in vivo activation remain scarce. Here, we report that ultrasound excitation of oleic acid-capped BaTiO3 (OA@BaTiO3) can result in an •R cascade and hence a means to conquer hypoxic tumors. Mechanistic studies find that the •R signal disappears when OA@BaTiO3 undergoes acid washing post-treatment, which is a common procedure for removing the unwanted byproduct BaCO3. Combined with the infrared spectrum analysis, acid treatment was proven to weaken the peaks at 2840-2970 cm-1 characteristic of -CH2- and terminal -CH3 stretching vibration of OA. There is compelling evidence that high temperature thermal oxidation of OA involves the generation of •R. Thus, acid washing is considered to remove the loosely bound yet catalytically active OA. And piezoelectric BaTiO3, a potential electron-hole redox catalyst, can sensitize these OA molecules and disintegrate them to •R. This unexpected discovery provides us with a distinctive mentality to seek diverse •R initiators for tumor ablation, as well as an additional perspective on the postprocessing of synthetic materials.

High-Entropy Materials for Lithium Batteries

High-entropy materials (HEMs) constitute a revolutionary class of materials that have garnered significant attention in the field of materials science, exhibiting extraordinary properties in the realm of energy storage. These equimolar multielemental compounds have demonstrated increased charge capacities, enhanced ionic conductivities, and a prolonged cycle life, attributed to their structural stability. In the anode, transitioning from the traditional graphite (372 mAh g−1) to an HEM anode can increase capacity and enhance cycling stability. For cathodes, lithium iron phosphate (LFP) and nickel manganese cobalt (NMC) can be replaced with new cathodes made from HEMs, leading to greater energy storage. HEMs play a significant role in electrolytes, where they can be utilized as solid electrolytes, such as in ceramics and polymers, or as new high-entropy liquid electrolytes, resulting in longer cycling life, higher ionic conductivities, and stability over wide temperature ranges. The incorporation of HEMs in metal–air batteries offers methods to mitigate the formation of unwanted byproducts, such as Zn(OH)4 and Li2CO3, when used with atmospheric air, resulting in improved cycling life and electrochemical stability. This review examines the basic characteristics of HEMs, with a focus on the various applications of HEMs for use as different components in lithium-ion batteries. The electrochemical performance of these materials is examined, highlighting improvements such as specific capacity, stability, and a longer cycle life. The utilization of HEMs in new anodes, cathodes, separators, and electrolytes offers a promising path towards future energy storage solutions with higher energy densities, improved safety, and a longer cycling life.

An Overview of Preparation for Different Azo Compounds

Azo compounds are a class of organic materials that have the group R-N=N-R' where the substitution group R and R' are aromatic or heterocyclic sides. The azo compounds have a variety of applications including dyes, pigments, and pharmaceuticals. The preparation and characterization of different azo compounds is an important area of research in organic synthesis. The azo compound synthesis typically involves the diazotization process for coupling between an aromatic amine and another aromatic compound containing an activating group such as -OH, -NH2, or -NR2. The reaction conditions must be carefully controlled to prevent side reactions, such as the formation of unwanted byproducts. Once synthesized, azo compounds can be characterized using a variety of techniques including UV-Vis spectroscopy, NMR spectroscopy, and mass spectrometry. UV-Vis spectroscopy is a commonly used technique for characterizing azo compounds. The absorption spectrum of an azo compound typically exhibits a strong absorption band in the visible region due to the delocalized π-electrons in the azo group. While in FTIR, the loss of the amine peak and showing a weak peak at about 1550 cm−1forthe (N=N) group, indicates the presence of Azo. The preparation and characterization of different azo compounds is a significant field of research in organic chemistry, which are applied as acid and base indicators, food coloring, optical switches, liquid crystal and in medicine. By carefully controlling the synthesis conditions and using a variety of characterization techniques, researchers can gain a better understanding of the properties and applications of these compounds.

The insight into reaction mechanism of diethylamine catalytic abatement over various Cu-based catalysts

This work investigated the reaction behaviors of diethylamine (DEA) catalytic oxidation on various Cu-based catalysts with different supports (TiO2, HZSM-5(27), HZSM-5(130) and S-1). It was found that the acidic environment of catalysts greatly influenced reaction pathways of DEA oxidation. On Cu5/TiO2 catalyst mainly with Lewis acidity, DEA preferentially dissociated through a two-step dehydrogenation to produce acetonitrile and ethylene, while on Cu5/HZSM-5(27) catalyst with strong Brønsted acidity, DEA could directly decompose into ethylamine and ethylene via N-C cleavage. Both pathways existed simultaneously over Cu5/HZSM-5(130) with decreased Brønsted acidity. Thereafter, acetonitrile could be further oxidized on the Cu5/TiO2 catalyst to generate a large amount of NOx via NCO(a) intermediates over-oxidation, while ethylamine on Cu5/HZSM-5 samples would convert to acetamide and then produced N2 and CO2. The Cu2+ species due to enriched Brønsted acid sites in Cu5/HZSM-5 catalysts ensured excellent N2 selectivity via internal SCR mechanism. Additionally, the strong Brønsted acidity of Cu5/HZSM-5(27) could induce the polymerization of carbonaceous intermediates and thereby resulted in severe coke deposition. As for Cu5/HZSM-5(130) and Cu5/S-1 with relatively lower Brønsted acidity and reducibility would release some unwanted gas-phase by-products like ethyl-isocyanate. This work provided useful guidance for designing NVOCs catalysts with high activity and less toxic by-products.

Mineral waste recycling, sustainable chemical engineering, and circular economy

The mineral processing industry is pivotal in natural resource extraction and historically contributes to environmental damages like land degradation and groundwater contamination. In the face of resource scarcity and environmental pollution, sustainable solutions are increasingly vital. The circular economy focuses on reusing, recycling, and reducing waste, which turns unwanted by-products into valuable assets. Sustainable chemical processes offer innovative solutions in waste material reclamation and integration into the production chain. These practices not only mitigate waste but also enable resource recovery, turning waste management costs into profits. Repurposing mineral waste reduces mining's environmental impact, lessens new mining needs, and yields economic advantages.

Transformation of waste into valuable materials: Utilizing waste printer powder to remove hazardous organic dye and pharmaceutical pollutants from wastewater

A global concern of considerable significance revolves around electronic waste and the contamination of water due to antibiotics and persistent organic dyes, leading to the emergence of antibiotic resistance and an alarming increase in environmental pollution. The substantial accumulation of waste printer powder generated by printers is undeniably an unwanted and valueless byproduct, as both its substantial production and recycling would result in significant financial burdens and environmental pollution challenges. Polypyrrole-grafted waste printer powder, (Ppy@wp), constitutes a viable solution due to its established reputation as a capable adsorbent. To maximize the reutilization of this waste powder, we have investigated a straightforward and practical approach for repurposing waste printer powder (wp) to craft a super magnetic Ppy@wp nanocomposite. This composite is put forth as a highly effective material for the elimination of methylene blue (MB) dye and tetracycline (TC) from solutions. The wp was mixed with pyrrole, followed by polymerization and carbonization to synthesize the final composite. The pollutant removal capacity of the as-prepared Ppy@wp nanocomposite has been evaluated by removing MB and TC. The Ppy@wp nanomaterial was found to be highly effective in removing 50 ppm of MB and TC with a removal rate of around 95.36% and 90.23%, respectively, within just 50 min. The Ppy@wp nanomaterial was evaluated for regeneration and desorption and it was shown to be effective for up to six cycles, with removal efficiency of TC being 79.23% and MB being 86.56%. This is a cost-effective, innovative, and highly efficient adsorbent process with a great perspective on environmental pollution clean-up. The result demonstrated that the synthesized material was magnetically separated from the solution within 2 min after adsorption. Therefore, this research has provided value-added significance for developing inexpensive composites from waste material to remove toxic chemicals from the waste stream.

Biocatalysts for biomethanol production: Advancements and future prospects

Biomethanol, a renewable and sustainable alternative to traditional fossil-fuel-derived methanol, has garnered considerable attention as a potential solution to mitigate greenhouse gas emissions and dependence on non-renewable resources. The utilization of biocatalysts in biomethanol production offers a promising avenue to achieve environmentally friendly and economically viable processes. Paper highlights the biocatalytic pathways involved in biomethanol synthesis. Particular emphasis is placed on microbial biocatalysts, such as methanogenic archaea and certain bacteria, which possess the unique capability of converting carbon dioxide and hydrogen into methanol through a series of enzymatic reactions. Additionally, enzyme-based systems derived from various microorganisms and genetically engineered organisms are also discussed as potential biocatalysts for biomethanol synthesis. Paper also delves into the current challenges and limitations faced in harnessing biocatalysts for biomethanol production. These challenges include substrate availability, low conversion rates, enzyme stability, and process scalability. Several strategies to address these issues are highlighted, including metabolic engineering, synthetic biology, and bioprocess optimization techniques. The advantages of utilizing biocatalysts for biomethanol production are outlined. Biocatalytic routes offer the advantage of operating under mild conditions, which reduces energy consumption and minimizes the production of unwanted by-products. Furthermore, the utilization of renewable feedstocks, such as carbon dioxide captured from industrial emissions or waste streams, enhances the sustainability of the process. The final section discusses future prospects and potential research directions in the field of biocatalytic biomethanol production. Advances in biotechnology, omics technologies, and computational modeling are poised to accelerate the discovery and optimization of novel biocatalysts, thereby unlocking the full potential of biomethanol as a sustainable fuel and chemical precursor. The use of biocatalysts for biomethanol production offers an attractive approach to establish a green and circular economy. With ongoing research and technological advancements, the field holds significant promise for reducing carbon emissions and transitioning towards a more sustainable energy landscape. However, to fully realize the potential of biocatalytic biomethanol production, interdisciplinary collaboration and concerted efforts are required to address existing challenges.

Enzymatic synthesis of S-adenosyl-l-homocysteine and its nucleoside analogs from racemic homocysteine thiolactone.

S-Adenosyl methionine (SAM)-dependent methyltransferases hold significant potential as tools for the biocatalytic synthesis of complex molecules due to their ability to methylate or alkylate substrates with high regio-, chemo-, and stereoselectivity. Recent advancements in enzyme-catalyzed S-methylation and S-alkylation of S-adenosyl homocysteine (SAH) using synthetic alkylation agents have expanded the scope of methyltransferases in preparative biocatalysis. This development has transformed SAH from an unwanted byproduct into a crucial - and currently expensive - reagent. In this report, we present a simple and scalable one-pot synthesis of SAH, starting from racemic homocysteine thiolactone and adenosine. This process is catalyzed by recombinant α-amino-ε-caprolactam racemase, bleomycin hydrolase, and SAH hydrolase. The reaction proceeds to completion with near-stoichiometric mixtures of reactants, driven by the irreversible and stereoselective hydrolysis of thiolactone, followed by the thermodynamically favorable condensation of homocysteine with adenosine. We demonstrate that this method can be utilized to supplement preparative methylation reactions with SAH as a cofactor, as well as to synthesize and screen S-nucleosyl homocysteine derivatives in the search for stabilized SAM analogs.

Environment and Inclusive Growth: Concerns and Solutions

The ecology and all of its components are suffering greatly as a result of the unchecked speed of development. At this rate, environmental degradation will have an impact on humanity and associated fields. In order to prevent the consequences of expansion from pushing the environment into a situation from which it is incapable of recovering, there should be ongoing, earnest efforts made towards sustainable development. The three pillars of ecodevelopment are the environment, humanity, and economy. A stable growth rate is necessary to attain a just balance between these pillars. Since agriculture employs the majority of the population, it also has an impact on the balance of the ecosystem. Because every unplanned step towards progress puts us back in the environmental front, we must thus be mindful of the boundaries of environmental challenges in order to achieve equitable economic growth. The hope for sustainable development lies in decreased deforestation, greater food security, conservative agricultural practices, the use of biopesticides, and prudent use of natural resources. To be effective, environmental policy probably needs to employ a variety of tools, each addressing a distinct aspect of the issue and attempting to minimise redundancies and pointless regulations. Appropriately pricing environmental inputs facilitates sustainable resource provision and use management. Long-term corporate investment in new technology and innovation is encouraged by a consistent and clear environmental policy, which also increases investment certainty. Environmental and economic success are interdependent. Economic activity and advancement depend on the natural environment because it provides the resources needed to produce goods and services and because it processes and absorbs waste and pollution, which are unwanted byproducts. This paper focuses on how environmental assets assist control risks associated with social and economic activities, flood risks, local climate regulation (temperature and air quality), and the availability of clean water and other resources.

Comparative Study on the effects of Urban Heat Islands using Remote Sensing and Geographical Information System for the Salem district, India

The ecology and all of its components are suffering greatly as a result of the unchecked speed of development. At this rate, environmental degradation will have an impact on humanity and associated fields. In order to prevent the consequences of expansion from pushing the environment into a situation from which it is incapable of recovering, there should be ongoing, earnest efforts made towards sustainable development. The three pillars of ecodevelopment are the environment, humanity, and economy. A stable growth rate is necessary to attain a just balance between these pillars. Since agriculture employs the majority of the population, it also has an impact on the balance of the ecosystem. Because every unplanned step towards progress puts us back in the environmental front, we must thus be mindful of the boundaries of environmental challenges in order to achieve equitable economic growth. The hope for sustainable development lies in decreased deforestation, greater food security, conservative agricultural practices, the use of biopesticides, and prudent use of natural resources. To be effective, environmental policy probably needs to employ a variety of tools, each addressing a distinct aspect of the issue and attempting to minimise redundancies and pointless regulations. Appropriately pricing environmental inputs facilitates sustainable resource provision and use management. Long-term corporate investment in new technology and innovation is encouraged by a consistent and clear environmental policy, which also increases investment certainty. Environmental and economic success are interdependent. Economic activity and advancement depend on the natural environment because it provides the resources needed to produce goods and services and because it processes and absorbs waste and pollution, which are unwanted byproducts. This paper focuses on how environmental assets assist control risks associated with social and economic activities, flood risks, local climate regulation (temperature and air quality), and the availability of clean water and other resources.

Monomer centred selectivity guidelines for sulfurated ring-opening copolymerisations.

Sulfur-containing polymers, such as thioesters and thiocarbonates, offer sustainability advantages, including enhanced degradability and chemical recyclability. However, their synthesis remains underdeveloped compared to that of their oxygen-containing counterparts. Although catalytic ring-opening copolymerization (ROCOP) can provide access to sulfur-containing polymers, these materials often exhibit uncontrolled microstructures and unpredictable properties. A comprehensive model that elucidates the factors determining selectivity in these catalytic reactions is still lacking, despite its central importance for advancing these polymerizations into widely applicable methodologies. In this study, we investigate the factors that lead to selectivity in sulfurated ROCOP across various monomer combinations, including thioanhydrides or carbon disulfide with epoxides, thiiranes, and oxetanes. We find that unwanted by-products primarily arise from backbiting reactions of catalyst-bound alkoxide chain ends, which can be mitigated by (i) selecting monomers that form primary alkoxide of thiolate chain ends, (ii) maximizing ring strain in the backbiting step, and (iii) timely termination of the polymerization. By applying these strategies, the selectivity of the catalytic ROCOP can be controlled and we successfully synthesized perfectly alternating poly(esters-alt-thioesters) from various oxetanes and the highly industrially relevant ethylene oxide. Our study thereby shifts the focus for achieving selectivity from catalyst to monomer choice providing valuable mechanistic insights for the development of future selective polymerizations, paving the way for sulfurated polymers as potential alternatives to current commodity materials.

Recovery of Ionic Liquid from the Model Solution Mixture Mimicking the Catalytically Hydrolyzed Cellulose Product Utilizing Amberlyst Ion-Exchange Resin

The hydrolysis of cellulose using ionic liquid (IL) has been extensively studied but there is limited understanding of the removal of IL from the biomass hydrolysate. Finding a suitable method for the recovery and reuse of IL is one of the biggest challenges before its large-scale application. Selecting an appropriate combined recovery process is very important. This study proposed a facile ion-exchange combined method for the recovery of IL from the modeled cellulose hydrolysate mixture containing sugars as well as γ-valerolactone (GVL) via an adsorption–desorption mechanism using sulfonic acid cation-exchange (Amberlyst 15 (H)) resin. The results showed that the resin could adsorb more than 94% of 1-ethyl-3-methylimidazolium chloride [Emim]Cl IL at ambient conditions within a contact time of 20 min. The other coexisting constituents like glucose and GVL have no significant effect on the adsorption efficiency of IL. The adsorption of IL on Amberlyst 15 (H) resin was observed to be pseudo-second-order adsorption. The regeneration of the adsorbed IL was possible up to 70% using low-cost, easily available sodium chloride (NaCl) solution. Similarly, despite the interference of other unwanted byproducts in the real biomass hydrolysate sample, an IL adsorption efficiency up to 51% was reached under similar operating conditions. This study thus opens the facile possibility of extracting and recycling IL used in the biomass hydrolysis process.

Engineering a Synthetic Escherichia coli Coculture for Compartmentalized de novo Biosynthesis of Isobutyl Butyrate from Mixed Sugars.

Short-chain esters are versatile chemicals that can be used as flavors, fragrances, solvents, and fuels. The de novo ester biosynthesis consists of diverging and converging pathway submodules, which is challenging to engineer to achieve optimal metabolic fluxes and selective product synthesis. Compartmentalizing the pathway submodules into specialist cells that facilitate pathway modularization and labor division is a promising solution. Here, we engineered a synthetic Escherichia coli coculture with the compartmentalized sugar utilization and ester biosynthesis pathways to produce isobutyl butyrate from a mixture of glucose and xylose. To compartmentalize the sugar-utilizing pathway submodules, we engineered a xylose-utilizing E. coli specialist that selectively consumes xylose over glucose and bypasses carbon catabolite repression (CCR) while leveraging the native CCR machinery to activate a glucose-utilizing E. coli specialist. We found that the compartmentalization of sugar catabolism enabled simultaneous co-utilization of glucose and xylose by a coculture of the two E. coli specialists, improving the stability of the coculture population. Next, we modularized the isobutyl butyrate pathway into the isobutanol, butyl-CoA, and ester condensation submodules, where we distributed the isobutanol submodule to the glucose-utilizing specialist and the other submodules to the xylose-utilizing specialist. Upon compartmentalization of the isobutyl butyrate pathway submodules into these sugar-utilizing specialist cells, a robust synthetic coculture was engineered to selectively produce isobutyl butyrate, reduce the biosynthesis of unwanted ester byproducts, and improve the production titer as compared to the monoculture.

Evaluation of different nitrogen sources on growth and fermentation performance for enhancing ethanol production by wine yeasts

The utilization of grape juice from low oenological value grape varieties for bioethanol production represent an alternative for diversification and value addition in viticulture. Optimizing Very High Gravity (VHG) fermentation can significantly increase ethanol productivity while reducing water and energy consumption. In this study, the impact of different nitrogen sources on growth and fermentative performance of locally selected yeast strains was investigated. Five yeast strains of species Saccharomyces cerevisiae and Zygosaccharomyces rouxii were cultured in both synthetic culture media and natural grape juice supplemented with ammonium sulfate (NH), yeast extract (YE), Fermaid K (FERM), and urea (U) at varying concentrations. Due to the very low fermentation rate, the Z. rouxii strain was excluded from the selection. The results obtained in synthetic medium showed that nitrogen sources that promoted growth (NH and YE) had minimal effects on fermentative performance and were highly dependent on the specific yeast strain. However, the combination of urea and ammonium favored the rate of sugar consumption. When validated in natural grape juice, urea combined with ammonium (U + NH 300 + 75 mg/L) improved both growth parameters and ethanol yield. Doubling the concentration (U + NH 600 + 150 mg/L) further enhanced sugar consumption and ethanol production while reducing unwanted by-products. The combined use of urea and ammonium exhibited a synergistic effect, making it a cost-effective nitrogen supplement for VHG fermentations.

An Approach towards the Conversion of Biomass Feedstocks into Biofuel Using a Zeolite Socony Mobil-5-Based Catalysts via the Hydrothermal Liquefaction Process: A Review

The conversion of biomass to biofuels as a renewable energy source is continuously gaining momentum due to the environmental concerns associated with using fossil fuels. Biomass is a cost-effective, long-term natural resource that may be converted to biofuels such as biodiesel, biogas, bio-oil, and biohydrogen using a variety of chemical, thermal, and biological methods. Thermochemical processes are one of the most advanced biomass conversion methods, with much potential and room for improvement. Among various thermochemical processes, hydrothermal liquefaction (HTL) is a promising technology that can convert higher water-content feedstocks into biofuel with significantly lower oxygen content and higher calorific value without requiring the biomass to be dried first. In HTL, temperature, pressure, residence time, catalyst, and solvent all play a vital role in bio-oil quality. This study provides a comprehensive review of the research and development on the effects of catalysts and the need to optimise existing catalysts for optimum biomass conversion into high-value bio-oil and other products. The catalyst of interest is ZSM-5, a heterogenous catalyst that has been seen to increase the hydrocarbon content and decrease oxygenated compounds and other unwanted by-products. The use and modification of this catalyst will play a vital role in generating renewable and carbon-neutral fuels.

Machinability of cupola slag incorporated LM11 matrix composites in turning: Surface roughness and MRR analysis

This study explores the potential of using cupola slag, a byproduct of cast iron production, as reinforcement in Al-4.5-Cu (LM11) matrix composites. The composites were fabricated using a low-cost stir casting method, with varying percentages of cupola slag (0 %, 3 %, 5 %, and 7 %) added to the matrix. The cast composites were then evaluated based on their microstructure, microhardness density and machinability indices, including material removal rate, surface roughness, chip thickness and chip analysis during dry turning. A full factorial design of experimentation was employed to determine the effects of different process inputs on machinability, with feed, spindle speed, and weight percentage of cupola slag as the variables. The results showed that 7 wt% cupola slag incorporation improved machinability, but beyond this percentage, the casting became unstable due to reduced wettability. This study offers valuable insights into the machinability of cupola slag embedded cast composites and the influence of different process inputs on their machinability by using a low-cost stir casting method and an unwanted byproduct as reinforcement, this approach offers a novel and sustainable alternative for the reinforcement of metal matrix composites.

Immobilizing graphitic carbon nitride on porous silica via hydrogen bonds for photocatalytic flow synthesis of azoxybenzene

Heterogeneous photocatalysis is an ideal method for eco-friendly synthesis of value-added chemicals. However, due to the limited penetration depth of photons and inefficient utilization of the catalytic active sites, the scalability of heterogeneous photocatalysis is restrained. Combining heterogeneous photocatalysis and flow system is a promising solution to optimize the light absorption and mass transfer; however, an affordable, practical design of the flow system and the immobilization method of the photocatalyst is still missing. Here, we report a flow system for heterogeneous photocatalytic synthesis of azoxybenzene and its derivatives from reductive coupling of nitrobenzene at a gram-scale using anchored graphitic carbon nitride (gCN) on porous silica (gCN-SiO2). The hydrogen bonds formed between the gCN and the tetramethoxysilane (TMOS) precursor during the dehydrative condensation process prevent unwanted leaching of catalyst, enabling photocatalytic flow synthesis of azoxybenzene with high selectivity, efficiency, and durability. Mechanistic studies reveals that the gCN-SiO2 regulates the photocatalytic reduction kinetics of nitrobenzene by facilitating the generation of nitrosobenzene and N-phenylhydroxylamine intermediates while preventing the formation of unwanted 4-phenylazophenol byproducts, resulting in efficient and selective synthesis of azoxybenzene. Our work provides an alternative path towards large scale heterogeneous photocatalysis.

Impact of bacterial admixtures on the compressive and tensile strengths, permeability, and pore structure of ternary mortars: Comparative study of ureolytic and phototrophic bacteria.

The addition of bacterial biomass to cementitious materials can improve strength and permeability properties by altering the pore structure. Photoautotrophic bacteria are understudied mortar bio-additives that do not produce unwanted by-products compared to commonly studied ureolytic species. This study directly compares the impact of the addition of heterotrophic Bacillus subtilis to photoautotrophic Synechocystis sp. PCC6803 on mortar properties and microstructure. Cellulose fibers were used as a bacteria carrier. A commercial concrete healing agent composed of dormant bacterial spores was also tested. Strength, water absorption tests, mercury intrusion porosimetry, differential scanning calorimetry, thermogravimetric analysis, and scanning electron microscopy were applied to experimental mortar properties. The photoautotrophic modifications had a stronger positive impact on mortar strength and permeability properties than sporulated heterotrophic modifications due to differences in surface properties and production of exopolysaccharides. The findings provide support for photoautotrophic species as additives for mortars to move away from ammonia-generating species.

(Selective) Isolation of acetic acid and lactic acid from heterogeneous fermentation of xylose and glucose

The present study focuses on the isolation of acetic and lactic acid from a fermentation broth produced by heterofermentative microorganisms using glucose and xylose as substrate. Especially xylose fermentation to lactic acid leads to unwanted by-product formation of acetic acid. Reactive liquid-liquid extraction is an energy-efficient downstream process, where the use of green solvents such as d-limonene opens the way to a more sustainable production. To find the optimum solvent/reactive extractant pairing, the reactive extractants trioctylamine, trioctylphosphine oxide, Aliquat 336, and tributyl phosphate were used diluted in 1-octanol, 1-decanol, d-limonene or a deep eutectic solvent. The phosphine-based extractants proved to be most effective for both acids. In the first extraction step, 19% of acetic acid and only 3% of lactic acid are extracted with trioctylphosphine oxide/1-octanol when the xylose feed is used without pH adjustment. The pKa value of the acids is responsible for the difference in extraction efficiency leading to the proposal of a two-step extraction separating first acetic acid and after pH adjustment, lactic acid can be extracted. The combination of trioctylphosphine oxide diluted in d-limonene leads to a surprisingly high selectivity for lactic acid isolation in the second extraction step. The present study shows for the first time that green solvents lead to similar extraction efficiencies compared to conventional solvents such as 1-octanol. For back extraction n-heptane and p-cymene are used as disintegration agents and water as stripping phase; n-heptane results in a lactic acid back extraction efficiency of up to 82% and p-cymene up to 70%. This shows that also for the back extraction p-cymene as a green disintegration agent leads to similar results as fossil-based n-heptane.

Facile, versatile and stepwise synthesis of high-performance oligomer acceptors for stable organic solar cells.

Oligomer acceptors haverecently emerged aspromising photovoltaic materialsfor achieving high power conversion efficiency (PCE) and long-term stability in organic solar cells (OSCs). However, the limited availability of diverse acceptors, resulting from the sole synthetic approach, has hindered their potential for future industrialization.In this study, we present a facile and effective stepwise approach that utilizes two consecutive Stille coupling reactions for the synthesis of oligomer acceptors. To demonstrate the feasibility of the novel approach, we successfully synthesize a trimer acceptor, Tri-Y6-OD, and further systematically investigate the impact of oligomerization on device performance and stability. The result reveals that this approach has significant advantages compared to the conventional method, such as reduced formation of unwanted by-products and lower difficulties in purification. Remarkably, the OSC based on PM6:Tri-Y6-OD achieves an impressive PCE of 18.03% and maintains 80% of the initial PCE (T80) for 1523h under illumination, surpassing the performance of the corresponding small molecule acceptor Y6-OD-based device. Furthermore, the versatility of the synthetic strategy in obtaining diverse acceptors is further demonstrated. Overall, our findings provide afacile, versatile and stepwisewayfor synthesizingoligomeric acceptors, thereby facilitating the development of stable and efficient OSCs.