Conversion Of Acid Research Articles

Rhenium-promoter-free ruthenium–zirconia catalyst for high-yield direct conversion of succinic acid to 1,4-butanediol in water

The direct conversion of succinic acid to 1,4-butanediol (1,4-BDO) in water was investigated using Ru deposited on oxygen-vacant zirconia (Ru–OvZrOx) as the catalyst. 1,4-BDO was produced in high yield (89.5 %) and space–time yield (0.19 h−1) at 200 °C. The proximity of Ru to OvZrOx stabilized the nanosized Ru0 particles, enabled hydrogen spillover, increased the acidity of the catalyst, and achieved intermediate adsorption. The Zrδ+ center (2 ≤ δ < 4)—which featured abundant Lewis acid sites and was adjacent to the Ov sites—activated the γ-butyrolactone ring-opening reaction via a route involving 2-hydroxytetrahydrofuran formation. The electron-rich Ru0 center facilitated heterolytic hydrogen dissociation, and the dissociated H– and H+ ions traveled to the Zrδ+ sites and water molecules via hydrogen-shuttling mechanism. Moreover, the weakly bonded hydrogen actively participated in the hydrodeoxygenation and hydrogenation of intermediates to 1,4-BDO.

Production of bio-based adipic acid using a combination of engineered Pseudomonas putida strains

Adipic acid is an industrially important dicarboxylic acid and an essential precursor in the synthesis of Nylon-6,6. Due to the environmental impact associated with the current synthetic methods for Nylon-6,6 production, greener alternatives based on renewable and bio-based feedstocks are needed. In the present study, the potential of two Pseudomonas putida strains engineered for muconic acid accumulation was used to produce adipic acid from the lignin-derived aromatic compound guaiacol. This was achieved by expressing genes enabling the conversion of guaiacol to catechol in the first strain, and the conversion of muconic acid to adipic acid via expression of the Bacillus coagulans enoate reductase gene in the second strain. Through process engineering, a 2-step production was designed in which 2.93 mM bio-adipic acid was produced, with a yield of 0.57 mol/mol. This is the first demonstration that process and strain engineering can be combined to obtain a complete bio-based route for adipic acid production from depolymerized lignin compounds using the robust P. putida chassis.

Advanced computational modelling for biofuel catalyst optimization: enhancing beta zeolite acidity for oleic acid upgrading

We explore here, through reactive force field (ReaxFF) molecular dynamics simulations, oleic acid upgrading on beta zeolite (BEA) regulated with nine silica-to-aluminium ratios (SARs) to investigate their acid-catalyzed deoxygenation and coking susceptibility. The selected computational descriptors involved conversion, hydrodeoxygenation, and decarboxylation/decarbonylation selectivity, biofuels yield, and coke deposition characteristics. Simulations were validated by 20.3 SAR available experimental data and used for the systematic study. High deoxygenation selectivity was found to be related to the structural sensitivity of BEA(100) on the upgrading mechanism. ReaxFF simulations revealed that altering the Al-substitution could greatly promote biofuel formation. Specifically, SARs towards the mid-region (SAR 47) favored gasoline production, while 31 SAR exploited diesel-like hydrocarbons. An optimum ratio of 37.4 SAR achieved maximum oleic acid conversion (69.8%), with high yields of gasoline and diesel fuels (15.6 and 20.4 wt%, respectively) and moderate coking (8.6 wt%). Density functional theory screening of metallic dopants allowed investigating of their deoxygenation and coke susceptibility, obtaining that Cu-BEA structure favored the optimal carbon and O-moiety adsorption (-3.89 and -1.8 eV, respectively). Furthermore, the economic and environmental analysis showed that Cu-dopped BEA displayed the lowest market price and global warming potential (71 USD/kg and 2.8 kg CO2-eq/kg).

A manganese-doped layered double hydroxide loaded with lactate oxidase and DNA repair inhibitors for synergistically enhanced tumor immunotherapy

Tumor immunotherapy has gained more and more attention in tumor treatment. However, the accumulation of lactic acid in tumor tissue inhibits the response of immune cells to form an immunosuppressive microenvironment (ISME). To reverse the ISME, an acid-responsive nanoplatform (termed as MLLN@HA) is reported for synergistically enhanced tumor immunotherapy. MLLN@HA is constructed by the co-loading of lactate oxidase (LOX) and DNA repair inhibitor (NU7441) in a manganese-doped layered double hydroxide (Mn-LDH), and then modified with hyaluronic acid (HA) for tumor-targeted delivery. After endocytosis by tumor cells, MLLN@HA decomposes and releases LOX, NU7441 and Mn2+ ions in the acidic tumor microenvironment. The released LOX catalyzes the conversion of lactic acid into hydrogen peroxide (H2O2), which not only alleviates the ISME, but also provides reactants for the Mn2+-mediated Fenton-like reaction to enhance chemodynamic therapy (CDT). Released NU7441 prevents CDT-induced DNA damage from being repaired, thereby increasing double-stranded DNA (dsDNA) fragments within tumor cells. Importantly, the released Mn2+ ions enhance the sensitivity of cyclic GMP-AMP synthase (cGAS) to dsDNA fragments, and activate the stimulator of interferon genes (STING) to induce an anti-tumor immune response. Such an orchestrated immune-boosting strategy ultimately achieves effective tumor growth inhibition and prevents tumor lung metastasis. Statement of significanceTo improve the efficacy of tumor immunotherapy, an innovative acid-responsive MLLN@HA nanoplatform was developed for synergistically enhanced tumor immunotherapy. The MLLN@HA actively targets to tumor cells through the interaction of HA with CD44, and then degrades to release LOX, NU7441 and Mn2+ ions in the acidic tumor microenvironment. The released LOX generates H2O2 for the Mn2+-mediated Fenton reaction and reverses the ISME by consuming lactate. NU7441 prevents DNA damage repair, leading to an increased concentration of free DNA fragments, while Mn2+ ions activate the cGAS-STING pathway, enhancing the systemic anti-tumor immune response. The orchestrated immune-boosting nanoplatform effectively inhibits tumor growth and lung metastasis, presenting a promising strategy for cancer treatment.

Synthesis of Linoleic Acid of Conjugated Isomers from Sesame (Sesamum Indicum) Seed Oil: Its Use and Effect in a Microstructured Product Type Oil-in-Water Emulsion

The development of functional foods is an area of great interest and innovation in the food industry. The use of conjugated linoleic acid (CLA) in food formulations has been growing in recent years due to its multiple health benefits. In this study, conjugated linoleic acid was obtained from sesame oil, and its use in the formulation of oil-in-water food emulsions was evaluated. Conjugated linoleic acid (CLA) was synthesized from the linoleic acid present in sesame oil using the alkaline isomerization method using proplyeneglycol as a solvent. The effect of alkali concentration (NaOH) and reaction time on the conversion of linoleic acid to CLA was evaluated. A 96.6% conversion of CLA was obtained with a NaOH concentration of 7% and a reaction time of 2 h. Emulsions were prepared using CLA as oil phase and soy lecithin, tween 80, carboxymethylcellulose as emulsifying agents. Emulsions with mixtures of carboxymethylcellulose and tween 80 were stable, presenting a non-Newtonian fluid behavior of pseudoplastic type (n&lt;1). The Ostwald-de-Waele model shows an optimal fit to the experimental data of apparent viscosity (R2&gt;0.99 ), and its microstructural characterization shows a homogeneous particle distribution. These results show that the alkaline isomerization process using propylene glycol as a solvent is an excellent alternative for the synthesis of CLA from vegetable oils such as sesame oil and its application in the development of microstructured products such as functional emulsions, and their subsequent application in the development of new food products with beneficial health characteristics.

CYP8B1 Catalyzes 12alpha-Hydroxylation of C27 Bile Acid: In Vitro Conversion of Dihydroxycoprostanic Acid into Trihydroxycoprostanic Acid.

Sterol 12α-hydroxylase (CYP8B1) is the unique P450 enzyme with sterol 12-oxidation activity, playing an exclusive role in 12α-hydroxylating intermediates along the bile acid (BA) synthesis pathway. Despite the long history of BA metabolism studies, it is unclear whether CYP8B1 catalyzes 12α-hydroxylation of C27 BAs, the key intermediates shuttling between mitochondria and peroxisomes. This work provides robust in vitro evidence that both microsomal and recombinant CYP8B1 enzymes catalyze the 12α-hydroxylation of dihydroxycoprostanic acid (DHCA) into trihydroxycoprostanic acid (THCA). On the one hand, DHCA 12α-hydroxylation reactivity is conservatively detected in liver microsomes of both human and preclinical animals. The reactivity of human tissue fractions conforms well with the selectivity of CYP8B1 mRNA expression, while the contribution of P450 enzymes other than CYP8B1 is excluded by reaction phenotyping in commercial recombinant enzymes. On the other hand, we prepared functional recombinant human CYP8B1 proteins according to a recently published protocol. Titration of the purified CYP8B1 proteins with either C4 (7α-hydroxy-4-cholesten-3-one) or DHCA yields expected blue shifts of the heme Soret peak (type I binding). The recombinant CYP8B1 proteins efficiently catalyze 12α-hydroxylation of both DHCA and C4, with substrate concentration occupying half of the binding sites of 3.0 and 1.9 μM and kcat of 3.2 and 2.6 minutes-1, respectively. In summary, the confirmed role of CYP8B1 in 12α-hydroxylation of C27 BAs has furnished the forgotten passageway in the BA synthesis pathway. The present finding might have opened a new window to consider the biology of CYP8B1 in glucolipid metabolism and to evaluate CYP8B1 inhibition as a therapeutic approach of crucial interest for metabolic diseases. SIGNIFICANCE STATEMENT: The academic community has spent approximately 90 years interpreting the synthesis of bile acids. However, the 12α-hydroxylation of intermediates catalyzed by CYP8B1 is not completely mapped on the classic pathway, particularly for the C27 bile acids, the pivotal intermediates shuttling between mitochondria and peroxisomes. This work discloses the forgotten 12α-hydroxylation pathway from dihydroxycoprostanic acid into trihydroxycoprostanic acid. The present finding may facilitate evaluating CYP8B1 inhibition as a therapeutic approach of crucial interest for metabolic diseases.

The CeO2 morphology modulates the density and catalytic performance of dual-active site for enhancing the palmitic acid conversion

Designing active sites with multi-function to meet the complicated reaction is a challenge task. Herein, we find that morphology of cerium oxide (CeO2) shows strong influence on the density and catalytic reactivity of dual-active site formed on it. Nanorods CeO2 (CeO2-NR) has large specific surface area and abundant oxygen vacancy (Ov), making small size of Ni (below 2 nm) highly disperse on it. However, 39.7 nm Ni poorly distributes on CeO2 composed of irregularly stacked particles (CeO2-NP), displaying much smaller specific surface area and fewer Ov compared with those on CeO2-NR. Small size Ni and abundant Ov show better abilities in activation of H2 and palmitic acid, respectively. Moreover, abundant Ov and highly dispersed Ni increase their intimacy on CeO2-NR. These make Ni/CeO2-NR catalyst has high density of Ni-Ov dual-active site, showing better synergetic catalytic performance for conversion of palmitic acid into alkanes than that on Ni/CeO2-NP.

Enhancement of hydrogen-rich gas production by acetic acid steam reforming: characterization of Ni–Co modified biochar-based catalysts

Abstract The development of cost-effective and highly efficient biochar-based catalysts is essential for the catalytic steam reforming process of bio-oil. In this study, pickling peanut shell biochar was used to prepare biochar-supported Ni/Co monometallic catalyst and biochar-supported nickel-Co bimetallic catalyst through the impregnation method. The catalytic effect of these catalysts on acetic acid (a bio-oil model compound) steam reforming was investigated. It was found that Co could enhance the dispersion of metal particles. The catalyst exhibited the best catalytic effect and significantly improved resistance to carbon deposition with a loading of 8 wt% and a Ni-to-Co ratio of 6:2. At the temperature of 600 °C and the S/C ratio of 3, the selectivity of H2 reached 84.48 %, and the conversion of acetic acid reached 95.49 %. A synergistic effect was observed between Ni and Co, leading to increased metal dispersion, enhanced reducibility, and a higher number of active centers. Co facilitates water dissociation and promotes the oxidation of C–H and mobile O, resulting in a faster decarbonization rate. The effective utilization of biochar-based catalysts and the rational utilization of bio-oil contribute to the timely achievement of carbon emission reduction targets.

The catalytic deoxygenation reaction temperature and N2 gas flow rate influence the conversion of soybean fatty acids into Green Diesel

BackgroundGreen diesel is a promising alternative as a petroleum replacement given the worldwide demand for petroleum fuel. Environmental issues have drawn public attention and concerns towards advancing renewable energy development. A catalytic deoxygenation (deCOx) was carried out to produce green diesel from soybean oil (SO) using a low-cost NiO-doped calcined dolomite (NiOCD) catalyst. MethodThe structure, chemical composition and morphology of NiOCD were comprehensively characterized by XRF, BET, TPD-CO2, SEM and TEM. In this study, the effect of two operating parameters, reaction temperature and flow rate of nitrogen, was discovered using a one-factor-at-a-time (OFAT) optimisation study. In addition, the life cycle cost analysis (LCCA) of stepwise catalyst preparation and green diesel production has been performed. Significant findingsAn optimal reaction temperature of 420 °C was found to provide the highest yield of green diesel (47.13 wt.%) with an 83.51% hydrocarbon composition. The ideal nitrogen flow rate, however, was found to be 50 cm3/min, which produced 41.80 wt.% of green diesel with an 88.63% hydrocarbon composition. The deoxygenation reaction was significantly impacted by both reaction temperature and nitrogen flow rate. According to LCCA, NiOCD catalyst has potential to lower the overall cost of producing green diesel compared to commercial zeolite catalysts.

Oil in food waste to methane by anaerobic digestion: Co-effects of mixing intensity and long chain fatty acid loading

Oil in the food waste can contribute improved energy yield by anaerobic digestion, and also poses an inhibition risk from the intermediate long chain fatty acids (LCFAs). The digestion performance partly depends on the solubility of oil/LCFAs concerned recently, while mixing intensity control can disturb the solubility characteristics. Combined with oil loading such a fundamental control parameter, co-effects of mixing intensity and oil loading on methanogenic characteristics were illuminated. A series of mixing intensities 0–240 rpm and oil/inoculum (F/I) ratios 0.2–1.2 were set to conduct a batch experiment, and relevant affecting mechanisms were further disclosed as well. It turned out that variation of mixing intensity could have effects on methanogenesis from oil in food waste. Increasing mixing intensity prolonged lag phase. Mixing intensity at 120 rpm was proved as a starting point to disturb LCFA inhibition. Methanogenic rates climbed to the top at F/I 0.4, and further increase loading resulted in the rate decline. Methanogenic potential release was also reduced with both mixing intensity and loading at higher values. Hereinto, oleic acid (C18:1) as a key LCFA in oil played an important role in inhibition, while higher mixing intensity and loading could promote degradation and conversion of another critical LCFA palmitic acid (C16:0). The study favors achieving a cost-effective strategy controlled by mixing intensity to promote safe energy improvement.

Synthesis and Biological Activity of Homohypotaurine Obtained by the Enzyme-Based Conversion of Homocysteine Sulfinic Acid Using Recombinant Escherichia Coli Glutamate Decarboxylase.

l-Homocysteine, formed from S-adenosyl methionine following demethylation and adenosine release, accumulates when the methionine recycling pathway and other pathways become impaired, thus leading to hyperhomocysteinemia, a biomarker in cardiovascular diseases, neurological/psychiatric disorders, and cancer. The partial oxidation of the l-homocysteine thiol group and its decarboxylation on C-alpha lead to the formation of l-homocysteinesulfinic acid (l-HCSA) and homohypotaurine (HHT), respectively. Both compounds are not readily available from commercial suppliers, which hinders the investigation of their biological activities. Herein, the chemical synthesis of l-HCSA, from l-homocystine, was the starting point for establishing the bio-based synthesis of HHT using recombinant Escherichia coli glutamate decarboxylase (EcGadB), an enzyme already successfully employed for the bio-based synthesis of GABA and its phosphinic analog. Prior to HHT synthesis, kcat (33.92 ± 1.07) and KM (38.24 ± 3.45 mM) kinetic constants were determined for l-HCSA on EcGadB. The results of our study show that the EcGadB-mediated synthesis of HHT can be achieved with good yields (i.e., 40% following enzymatic synthesis and column chromatography). Purified HHT was tested in vitro on primary human umbilical vein endothelial cells and rat cardiomyoblasts and compared to the fully oxidized analog, homotaurine (OT, also known as tramiprosate), in widespread pharmaceutical use. The results show that both cell lines display statistically significant recovery from the cytotoxic effects induced by H2O2 in the presence of HHT.

Conversion of soybean oil under subcritical water conditions into liquid biofuels with low oxygen contents

Although the hydrotreatment of natural triglycerides is a well-established route for producing sustainable aviation fuel and renewable diesel, its high hydrogen consumption is a concern. The hydrothermolysis of natural triglycerides is considered a highly promising alternative route; however, the correlation between process parameters and fuel properties and detailed chemical structures of the produced fuel have not been established. Herein, we investigated the conversion of soybean oil to gasoline-, jet fuel- and diesel-fraction hydrocarbons with low oxygen contents. The properties of fuels produced under various reaction conditions were analyzed comprehensively using simulated distillation, total acid number (TAN), and elemental analysis. Under the optimized reaction conditions of 420 °C, 4.5 MPa, an oil-to-water ratio of 6:1, and reaction time of 10 min, 26 % gasoline-, 62 % jet fuel-, and 90 % diesel-range hydrocarbons with a low oxygen content of 5.1 %, low TAN of 0.04 mg KOH g−1, and high calorific value of 42.7 MJ kg−1 resulted. To elucidate the reaction mechanism, the liquid products produced from soybean oil were analyzed using comprehensive two-dimensional gas chromatography combined with time-of-flight mass spectrometry. In addition, based on the oleic acid conversion under varying hydrothermal conditions, we proposed deoxygenation, cracking, cyclization, and aromatization pathways. The findings of this study present possibilities for producing sustainable biofuels with low oxygen contents for the aviation industry.

Atmosphere toward regulation of MoO3 microstructure for lactic acid hydrodeoxygenation to propionic acid

Regulation of MoO3 microstructure was explored at different atmospheres, which was further evaluated for catalytic performance on lactic acid hydrodeoxygenation. Catalyst structure was characterized by XRD, FT-IR, HRTEM, and oxygen vacancies were measured by EPR and XPS spectra. It was found that the direct H2-Ar treatment generated an obvious change in MoO3 microstructure to form rich oxygen vacancies in MoO3-H, and the succedent H2-Ar treatment had negligible influence in MoO3-A-H, indicating that the non-crystallizing MoO3 is effortless to generate oxygen vacancy with H2-Ar atmosphere treatment. Correspondingly, MoO3-H achieved 58.6 % of lactic acid conversion and 64.7 % of propionic acid selectivity much higher than MoO3-A-H with 41.7 % of lactic acid conversion and 56.9 % of propionic acid selectivity, which also outperformed most of the LA hydrodeoxygenation catalysts in propionic acid selectivity. This work demonstrates that the calcined atmospheres can efficiently regulate MoO3 microstructure to form rich oxygen vacancies for lactic acid hydrodeoxygenation to propionic acid.

Efficient biodiesel production by sulfonated carbon catalyst derived from waste glycerine pitch via single-step carbonisation and sulfonation

Glycerine pitch is a highly alkaline residue from the oleochemical industry that contains glycerol and contaminants, such as water, soap, salt and ash. In this study, acidic heterogeneous glycerol-based carbon catalysts were synthesised for biodiesel production via single-step partial carbonisation and sulfonation using pure glycerol and glycerine pitch, producing products labelled as SGC and SGPC, respectively. Carbon materials were obtained by heating glycerol and concentrated sulfuric acid (1:3) at 200℃ for 1 h. The produced SGC and SGPC displayed high densities of sulfonic group (–SO3H), i.e. 1.49 and 1.00 mmol·g−1, respectively, alongside carboxylic (–COOH) and phenolic (–OH) acid. In the catalytic evaluation, excellent oleic acid conversions of 96.0 ± 0.4 % and 92.4 ± 0.5 % were achieved using SGC and SGPC, respectively, under optimised reaction conditions: 1:10 M ratio of oleic acid to methanol, 5 % (w/w) catalyst, 64℃ and 5 h. SGPC was found to be recyclable with 68.5 % conversion after the 6th cycle, which was attributed to the loss of –SO3H and catalyst deactivation by the deposition of oleic acid on its surface. Remarkably, despite the impurities present in the glycerine pitch, the obtained results demonstrated that the reactivity of SGPC is comparable to SGC and superior to that of commercial solid acid catalysts, which demonstrated that the presence of impurities appears to have minimal impact on the production of carbon materials and their properties.

Interplay between Bile Acids and Intestinal Microbiota: Regulatory Mechanisms and Therapeutic Potential for Infections.

Bile acids (BAs) play a crucial role in the human body's defense against infections caused by bacteria, fungi, and viruses. BAs counteract infections not only through interactions with intestinal bacteria exhibiting bile salt hydrolase (BSH) activity but they also directly combat infections. Building upon our research group's previous discoveries highlighting the role of BAs in combating infections, we have initiated an in-depth investigation into the interactions between BAs and intestinal microbiota. Leveraging the existing literature, we offer a comprehensive analysis of the relationships between BAs and 16 key microbiota. This investigation encompasses bacteria (e.g., Clostridioides difficile (C. difficile), Staphylococcus aureus (S. aureus), Escherichia coli, Enterococcus, Pseudomonas aeruginosa, Mycobacterium tuberculosis (M. tuberculosis), Bacteroides, Clostridium scindens (C. scindens), Streptococcus thermophilus, Clostridium butyricum (C. butyricum), and lactic acid bacteria), fungi (e.g., Candida albicans (C. albicans) and Saccharomyces boulardii), and viruses (e.g., coronavirus SARS-CoV-2, influenza virus, and norovirus). Our research found that Bacteroides, C. scindens, Streptococcus thermophilus, Saccharomyces boulardii, C. butyricum, and lactic acid bacteria can regulate the metabolism and function of BSHs and 7α-dehydroxylase. BSHs and 7α-dehydroxylase play crucial roles in the conversion of primary bile acid (PBA) to secondary bile acid (SBA). It is important to note that PBAs generally promote infections, while SBAs often exhibit distinct anti-infection roles. In the antimicrobial action of BAs, SBAs demonstrate antagonistic properties against a wide range of microbiota, with the exception of norovirus. Given the intricate interplay between BAs and intestinal microbiota, and their regulatory effects on infections, we assert that BAs hold significant potential as a novel approach for preventing and treating microbial infections.

Atmospheric reactive nitrogen conversion kicks off the co-directional and contra-directional effects on PM2.5-O3 pollution

As the two important ambient air pollutants, particulate matter (PM2.5) and ozone (O3) can both originate from gas nitrogen oxides. In this study, applied by theoretical analysis and machine learning method, we examined the effects of atmospheric reactive nitrogen on PM2.5-O3 pollution, in which nitric oxide (NO), nitrogen dioxide (NO2), gaseous nitric acid (HNO3) and particle nitrate (pNO3−) conversion process has the co-directional and contra-directional effects on PM2.5-O3 pollution. Of which, HNO3 and SO2 are the co-directional driving factors resulting in PM2.5 and O3 growing or decreasing simultaneously; while NO, NO2, and temperature represent the contra-directional factors, which can promote the growth of one pollutant and reduce another one. Our findings suggest that designing the suitable co-controlling strategies for PM2.5-O3 sustainable reduction should target at driving factors by considering the contra-directional and co-directional effects under suitable sensitivity regions. For co-directional driving factors, the design of suitable mitigation strategies will jointly achieve effective reduction in PM2.5 and O3; while for contra-directional driving factors, it should be more patient, otherwise, it is possible to reduce one item but increase another one at the same time.

MBX-7591: a promising drug candidate against drug-resistant fungal infections.

Invasive fungal infections (IFIs) caused by pathogenic fungi pose a significant public health concern, particularly for immunocompromised individuals. Mortality rates for IFIs remain high, and currently available treatment options are limited. Existing antifungal agents often suffer from limited clinical efficacy, poor fungicidal activity within the host, potential toxicity, and increasing ineffectiveness due to emerging resistance, especially against triazole drugs, the current mainstay of antifungal treatment. A recent study has identified MBX-7591, a small molecule with promising antifungal activity against Aspergillus fumigatus and other pathogenic fungi, including strains resistant to triazoles (C. Gutierrez-Perez, C. Puerner, J. T. Jones, S. Vellanki, E. M. Vesely, et al., mBio e01166-24, 2024, https://doi.org/10.1128/mbio.01166-24). This novel compound appears to inhibit stearoyl-CoA 9-desaturase, a key enzyme involved in fungal fatty acid biosynthesis. By disrupting the conversion of saturated fatty acids to oleic acid, MBX-7591 offers a unique mechanism of action, potentially reducing the risk of resistance development. Here, we now discuss the implications of these groundbreaking findings for overcoming antifungal drug resistance.

Anchoring nickel sites on ceria-coated silica to enhance the catalytic stability for the vapor phase levulinic acid hydrogenation

The preparation of the binary metal NiCe-based catalysts involved a 2-step protocol, the ceria was first coated on SiO2 which was then utilized to disperse Ni nanoparticles. Various techniques including N2 adsorption/desorption, ICP-OES, XRD, HRTEM, XPS, H2-chemisorption, H2-TPR, NH3-TPD, and TG etc. were performed to study the microstructure, redox, acid property and deactivation. The results revealed that CeO2 and metallic Ni were well dispersed on the support surface, the synergistic effect between the two metal species was conserved well. The content of CeO2 had considerable effects on redox and metallic properties rather than the acidic property. The dispersion of metallic Ni played a dominant role in promoting the catalytic activity. The levulinic acid conversion attained 84.0 % with a γ-valerolactone selectivity of 98.8 % on Ni/SiO2@2CeO2 sample with the highest dispersion of 9.8 %. The amorphous CeO2 suppressed the sintering of metallic Ni nanoparticles and improved the coke resistance, leading to better catalytic activity within 20 h time on stream.

Effect of phytic acid/rust conversion layer on corrosion protection of rusty mild steel

In this study, a rust/phytic acid (rust/PA) conversion layer was prepared on rusty mild steel by dipping rusty steel panels into a phytic acid solution. After treating with phytic acid, the free phosphate group in the conversion layer chelated with Fe3+ and generated insoluble salt, which could form a new dense conversion layer. The dense rust/PA conversion layer effectively strengthened the interfacial bonding between the coatings and rusty metal substrate and exhibited good corrosion protection and defect healing abilities.

Significant production of alkyl halides from (aliphatic) carboxylic acids in the UV/chlorine process

Ultraviolet radiation combined with free chlorine (UV/chlorine) is an attractive alternative to UV or chlorination alone for disinfection. However, •OH and Cl• radicals from UV/chlorine have recently raised increasing concerns about the possible formation of chlorinated products. A significant quantity of alkyl halides was generated from aliphatic carboxylic acids in the UV/chlorine process, in contrast to the absence of any detectable alkyl halides during chlorination alone. During the UV/chlorine process, the formation of CH3Cl, CH3CH2Cl and CH3CH2CH2Cl were was observed from acetic acid, propionic acid and n-butyric acid, respectively. The maximum yield of CH3Cl was up to 54.6 % when acetic acid was treated at a chlorine to precursors (Cl/P) ratio of 4.0. In addition to CH3Cl, CH2Cl2 and CHCl3 were also detected as the products of acetic acid. The presence of bromide ions resulted in a reduction in the yields of chloroalkanes, the formation of bromine byproducts, and an increase in the total amount of halocarbons. Hydroxyl radicals and chlorine radicals were identified as key reactants in the radical quenching experiments. The reactions described in this paper contribute to the understanding of the mechanism of halogenated byproduct formation during the UV/chlorine process. SynopsisThe radicals resulting from UV/chlorine lead to the conversion of carboxylic acids into a significant amount of alkyl halides that would not be generated by chlorination alone.