Solvent Combinations Research Articles

Tuning and Balancing the Donor Number of Lithium Salts and Solvents for High-Performance Li Metal Anode.

The low reversibility of Li deposition/stripping in conventional carbonate electrolytes hinders the development of lithium metal batteries. Herein, we proposed a combination of solvents with a moderate donor number (DN) and LiNO3 as the sole salt, which has rarely been attempted due to its low solubility or dissociation degree in common solvents. It is found that the DN value of solvents is highly correlated to the reversibility of Li deposition behavior when LiNO3 is applied as the sole salt. The combination of LiNO3 and solvents with moderate DN behaves like a quasi-concentrated electrolyte even at a common or moderate concentration, while neither the solvents with poor solubility and low dissociation for LiNO3 (which usually corresponds to a low DN) nor the solvents with high dissociation for LiNO3 (which usually corresponds to an overly high DN) can achieve a high reversibility for low conductivity or excessive solvent decomposition. As a result, a Coulombic efficiency as high as 99.6% for Li deposition/stripping is achieved with the optimized combination. We believe this work will give a better understanding of the role of anions and solvents in the regulation of the solvation structure, and DN can be utilized as an important guideline to sieve suitable solvents for LiNO3 as the main salt to exhibit intriguing properties beyond traditional cognition.

Assessment of Chemical Constituents of <i>Allium sativum</i> Essential Oil Extracted by using Hydrodistillation Technique and their Pharmacological Potential

The current study was based on identification of chemical components and pharmacological potential of Allium sativum essential oil. The pharmacological properties mainly antioxidant, anti-inflammatory and anti-diabetic potential of Allium sativum Essential Oil (ASEO) were also studied. Allium sativum is a traditional medicinal plant of the Alliaceae family. The extracted essential oil from fresh bulbs of Allium sativum through hydro distillation process was further analyzed by GC-MS. To determine the potential of Allium sativum essential oil for reducing inflammation and preventing diabetes, evaluation of antioxidant assays, protein denaturation and glucose absorption by yeast cells were studied. The results explained the presence of several organosulfur compounds that were identified by using different combinations of non-polar solvents mainly represented as Diallyldisulfide, Methyl Allyl Disulfide, Methyl Allyl Trisulfide, Diallyltrisulfide and Diallyltetrasulfide. The antioxidant potential of ASEO expressed as IC50 values of DPPH, ABTS, β-carotene assay, Nitric Oxide, superoxide, hydroxyl scavenging and metal chelating were 5.93 mg/ml, 2.1 mg/ml, 7.94 mg/ml, 5.49 μg/ml, 11.55 μg/ml, 7.66 μg/ml and 10.60 μg/ ml respectively. Further, total phenolic level, total flavonoid level, FRAP assay and total antioxidant capacity were evaluated and they were as follows: 4.99 ± 0.41 mg GAE/g, 98.46 ± 0.16 mg QE/g, 4.99 ± 0.26 mg/g and 15.80 ± 0.14 mg/g. Furthermore, the anti-inflammatory assay was assessed by considering the protein denaturation method which exhibits IC50 value 3.53μg/ml. In addition to this, anti-diabetic potential was assessed by considering glucose absorption by yeast cells at various glucose concentrations (5mM, 10mM, 25mM) which indicated that the ASEO enhanced glucose uptake via the yeast cell membrane. Upregulation of glucose was reported with sequential elevations in the ASEO concentration. Based on the above results, it was revealed that Allium sativum essential oil exhibits reasonable antioxidant, anti-inflammatory and anti-diabetic activity that could be considered as an alternative therapeutic agent in inflammatory diseases. However, future research is required to isolate prominent functional components to determine the observed potential in preclinical studies.

Environmentally Friendly Analytical Methods for Quantitative Measurement of Sofosbuvir in Pharmaceutical Formulations: Comparison of HPTLC and UV Spectrophotometric Approaches

For the quantitative measurement of sofosbuvir (SFR) in pharmaceutical formulation, high-performance thin-layer chromatographic (HPTLC) and environmentally friendly UV spectrophotometric approaches have been developed. HPTLC stationary phases were silica gel 60 F₂₅₄-coated aluminium plates. Toluene, chloroform, and ethanol were mixed 4:4:1 v/v/v. This mobile phase produced tiny spots of SFR with Rf 0.30±0.01. SFR was densitometrically analysed at 267nm in absorbance mode. Peak area showed great linearity (r2 =0.998) in the dilution range of 100–800ng/spot. A solvent combination of methanol and water was utilised for the UV spectrophotometric technique. First, a stock solution of SFR was made in methanol, and then it was diluted further in water. Absorption maxima were observed at 261nm for the SFR standard solution. Beer-law Lambert's was followed by the SFR at an r2 value of 0.999 at 10-50ng/mL. Both methods met ICH standards for precision, LOD, LOQ, accuracy and specificity. Statistical study validated the methods as reliable and accurate for the estimation of the SFR. The established procedures can be applied to the regular analysis of SFR drugs and pharmaceuticals.

The application of electrosprayed minocycline-loaded PLGA microparticles for the treatment of glioblastoma.

The survival of patients with glioblastoma multiforme (GBM), the most common and invasive form of malignant brain tumors, remains poor despite advances in current treatment methods including surgery, radiotherapy, and chemotherapy. Minocycline is a semi-synthetic tetracycline derivative that has been widely used as an antibiotic and more recently, it has been utilized as an antiangiogenic factor to inhibit tumorigenesis. The objective of this study was to investigate the utilization of electrospraying process to fabricate minocycline-loaded poly(lactic-co-glycolic acid) (PLGA) microparticles with high drug loading and loading efficiency and to evaluate their ability to induce cell toxicity in human glioblastoma (i.e., U87-MG) cells. The results from this study demonstrated that solvent mixture of dicholoromethane (DCM) and methanol is the optimal solvent combination for minocycline and larger amount of methanol (i.e., 70:30) resulted in a higher drug loading. All three solvent ratios of DCM:methanol tested produced microparticles that were both spherical and smooth, all in the micron size range. The electrosprayed microparticles were able to elicit a cytotoxic response in U87-MG glioblastoma cells at a lower concentration of drug compared to the free drug. This work provides proof of concept to the hypothesis that electrosprayed minocycline-loaded PLGA microparticles can be a promising agent for the treatment of GBM and could have potential application for cancer therapies.

Effects of Microfluidic Shear on the Plasmid DNA Structure: Implications for Polymeric Gene Delivery Vectors.

Microfluidic manufacturing of advanced gene delivery vectors necessitates consideration of the effects of microfluidic shear forces on the structural integrity of plasmid DNA (pDNA). In this paper, we expose pDNA to variable shear forces in a two-phase, gas-liquid microfluidic reactor and apply gel electrophoresis to analyze the products of on-chip shear-induced degradation. The effects of shear rate, solvent environment, pDNA size, and copolymer complexation on shear-induced degradation are investigated. We find that small naked pDNA (pUC18, 2.7 kb) exhibits shear rate-dependent shear degradation in the microfluidic channels in a mixed organic solvent (dioxane/water/acetic acid; 90/10/<0.1 w/w/w), with the extents of both supercoil isoform relaxation and complete fragmentation increasing as the maximum shear rates increase from 4 × 105 to 2 × 106 s-1. However, over the same range of shear rates, the same pDNA sample shows no evidence of microfluidic shear-induced degradation in a pure aqueous environment. Quiescent control experiments in the same mixed organic solvent prove that a combination of solvent and shear forces is involved in the observed shear-induced degradation. Furthermore, we show that shear degradation effects in mixed organic solvents can be significantly attenuated by complexation of pDNA with the block copolymer polycaprolactone-block-poly(2-vinylpyridine) prior to exposure to microfluidic shear. Finally, we demonstrate that medium (pDSK519, 8.1 kb) and large (pRK290, 20 kb) naked pDNA are more sensitive to shear-induced microfluidic degradation in the mixed organic solvent environment than small pDNA, with both plasmids showing complete fragmentation even at the lowest shear rate, although we found no evidence of shear-induced damage in water for the largest investigated naked pDNA even at the highest flow rate. The resulting understanding of the interplay of the solvent and shear effects during microfluidic processing should inform microfluidic manufacturing routes to new gene therapy formulations.

Organic solvent separation using carbon nanotube-interlayered thin film composite membrane

The intercalation of carbon nanotubes (CNTs) interlayer has been considered an effective way to improve the membrane performance in water treatment process. However, the effectiveness of CNTs interlayer on membrane performance enhancement for organic solvent separation has not been examined yet. Herein, a polyketone (PK)-based CNTs-interlayered thin-film composite (TFC) polyamide (PA) membrane was fabricated and applied in organic solvent reverse osmosis (OSRO) process for the first time. The role of CNTs interlayer on both PA formation regulation and permeance enhancement was investigated. Results demonstrate that the membrane permeance was enhanced three times higher with rejection remained at 99.2% when using 5 wt% methyl tert-butyl ether (MTBE) in methanol. By comparing the separation performances of three different kinds of solvent combinations (methanol/toluene, methanol/MTBE, and acetonitrile/toluene), the interactions between selective layer and different solvent mixtures were first considered as one of the factors affecting the rejection, and were analyzed based on Hansen solubility parameters (HSP) theory. This work provides insights into the high-performance OSRO membrane design and the solvent separation mechanism.

Aluminium Matrix Composite Materials Reinforced by 3D-Printed Ceramic Preforms.

This article employed the fused deposition modelling (FDM) method and gas-pressure infiltration to manufacture alumina/AlSi12 composites. Porous ceramic skeletons were prepared by FDM 3D printing of two different alumina powder-filed filaments. The organic component was removed using a combination of solvent and heat debinding, and the materials were then sintered at 1500 °C to complete the process. Thermogravimetric tests and DTA analysis were performed to develop an appropriate degradation and sintering program. Manufactured skeletons were subjected to microstructure analysis, porosity analysis, and bending test. The sintering process produced porous alumina ceramic samples with no residual carbon content. Open porosity could occur due to the binder's degradation. Liquid metal was infiltrated into the ceramic, efficiently filling any open pores and forming a three-dimensional network of the aluminium phase. The microstructure and characteristics of the fabricated materials were investigated using high-resolution scanning electron microscopy, computer tomography, hardness testing, and bending strength testing. The developed composite materials are characterized by the required structure-low porosity and homogenous distribution of the reinforcing phase, better mechanical properties than their matrix and more than twice as high hardness. Hence, the developed innovative technology of their manufacturing can be used in practice.

Identifying greener solvents for square wave voltammetry applications in functional food analysis

Electrochemical methods, specifically square wave voltammetry (SWV) offer fast, portable, and quantitative screening for antioxidant levels and lipid degradation in consumer products. Initial studies within our research group utilized benzene as the non-polar component in solvent systems utilized for analysis. In order to explore additional applications of SWV, less hazardous solvent systems that maintain or improve on previous figures of merit for analytes of interest are necessary. To this extent, ethanol was selected as the polar solvent under the 7th principle of green chemistry (use of renewable feedstocks). To replace our non-polar species (benzene), four solvent candidates were identified under the 5th principle of green chemistry (safer solvents and auxiliaries) including diethyl ether, acetonitrile, isopropyl alcohol, and ethyl acetate. Each solvent was investigated on its own, and then in varying combinations of v/v ratios with ethanol. Each solvent combination was used to investigate the limit of detection, lower limit of quantitation, sensitivity, and linearity of previously studied antioxidants butylated hydroxytoluene, sesamol, and rosemary extract. Each antioxidant was found to yield improved figures of merit depending on the solvent combination tested. After comparing all antioxidant figures of merit, it was found that 50%–50% ethanol—acetonitrile and 50%–50% ethanol—ethyl acetate were within the top five solvent systems for all antioxidants tested, providing a more green alternative to benzene solvent systems.

Bio Water Based Liquid Penetrants and Magnetics: a safer and cost-efficient solution for today

The objective of this paper is to present a study on the contribution of the superficial methods (Liquid Penetrants and Magnetic Testing (MT) liquids) in the NDT industry to the European Union and International targets of achieving climate neutrality. Bio water based liquid penetrants and MT liquids are available since some years in the NDT industry and are already widely used by medium and large companies worldwide, but their use has been limited in the past due to: higher costs, lower sustainability awareness, practical application process. (Please see previous contributions here: https://www.ndt.it/uk/documents.asp for technical papers presented on water-based liquid penetrants and MT liquids). Recently, the combination of higher oil and solvents prices internationally and an increased environmental consciousness by most Companies worldwide have turned the situation, so nowadays more and more Companies use safer Bio water-based products in their everyday work to achieve better operator and environment safety and lower overall costs. This paper will present effectively the advantages for the operator, the environment, and the Companies’ global costs of using Bio water based liquid penetrants and MT liquids in their NDT quality control process, through: a) A review of the updated applicable International Standards; b) An analysis of the safety and costs advantages of using Bio water based liquid penetrants and MT liquids compared to VOCs-containing alternatives; c) Real Companies case studies in the NDT industry; d) Examples of indications using Bio water based penetrants and MT liquids on metal pieces and on artificial defects as described in the International Standards.

Synergistic combination of natural deep eutectic solvent and chemical vapor generation for trace determination of As, Cd, Hg and Pb in drug samples by inductively coupled plasma optical emission spectrometry

Synergistic combination of natural deep eutectic solvent and chemical vapor generation for trace determination of As, Cd, Hg and Pb in drug samples by inductively coupled plasma optical emission spectrometry

Combined sulfuric acid and choline chloride/glycerol pretreatment for efficiently enhancing enzymatic saccharification of reed stalk

In this study, an efficient combination of pretreatment solvents involving Choline chloride/Glycerol (ChCl/Gly) and H2SO4 was firstly developed to assess the pretreatment performance and determine optimal pretreatment conditions. The results illustrated that the H2SO4-[ChCl/Gly] combination efficiently removed lignin (52.6%) and xylan (80.5%) from the pretreated reed stalk, and subsequent enzymatic hydrolysis yielded 91.1% of glucose. Furthermore, several characterizations were conducted to examine the structural and morphological changes of the reed stalk, revealing apparently enhanced accessibility (128.4 to 522.6 mg/g), reduced lignin surface area (357.9 to 229.5 m2/g), and substantial changes on biomass surface. Based on the aforementioned study, possible mechanisms for the H2SO4-[ChCl/Gly] pretreatment of reed stalks were proposed. The comprehensive understanding of combined H2SO4-[ChCl/Gly] pretreatment system for enhancing the saccharification of the reed stalk was interpreted in this work. Overall, this novel approach could be efficiently applied to pretreat and saccharify reed stalks, empowering the biomass refining industry.

The Unified Redox Scale for All Solvents: Consistency and Gibbs Transfer Energies of Electrolytes from their Constituent Single Ions.

We have devised the unified redox scale Eabs H2O , which is valid for all solvents. The necessary single ion Gibbs transfer energy between two different solvents, which only can be determined with extra-thermodynamic assumptions so far, must clearly satisfy two essential conditions: First, the sum of the independent cation and anion values must give the Gibbs transfer energy of the salt they form. The latter is an observable and measurable without extra-thermodynamic assumptions. Second, the values must be consistent for different solvent combinations. With this work, potentiometric measurements on silver ions and on chloride ions show that both conditions are fulfilled using a salt bridge filled with the ionic liquid [N2225 ][NTf2 ]: if compared to the values resulting from known pKL values, the silver and chloride single ion magnitudes combine within a uncertainty of 1.5 kJ mol-1 to the directly measurable transfer magnitudes of the salt AgCl from water to the solvents acetonitrile, propylene carbonate, dimethylformamide, ethanol, and methanol. The resulting values are used to further develop the consistent unified redox potential scale Eabs H2O that now allows to assess and compare redox potentials in and over six different solvents. We elaborate on its implications.

Determination of catechol in water with deep eutectic supramolecular solvents-assisted magnetic κ-carrageenan nanoparticles

A combination of magnetic κ-carrageenan nanoparticles and deep eutectic supramolecular solvents used for extraction of catechol from water was evaluated by the magnetic dispersion solid phase extraction method. The magnetic κ-carrageenan nanoparticles (KC@Fe3O4MNPs) and the deep eutectic supramolecular solvent (DESP) were characterised by 1H NMR, FT-IR, XRD, SEM, VSM, TG, and BET. The adsorption kinetics, adsorption isothermal model, adsorption thermodynamics and effects of pH and salt concentration were investigated. Additionally, the factors used in the desorption process, such as the type, dosage, concentration and time, were analysed. Under the optimised conditions, the analytes were linear over the range 5–5000 ng mL−1, with a correlation coefficient greater than 0.999 and detection and quantitation limits of 1.6 and 4.7 ng mL−1, respectively. The procedure was successfully applied to determinations of the analytes of interest in spiked water samples with relative average recoveries ranging from 94.3% to 101.5%. These results indicated that the combination of functionalized magnetic nanoparticles and DESP had high specificity and extraction efficiency for catechol and will be a feasible alternative to conventional analyses of organic phenolic pollutants in water.

Effect of solvent mixtures on the unique morphology for photocatalytic activity of Bi2S3 nanoparticles synthesized by microwave irradiation method

Unique morphologies of Bi2S3 nanostructures were synthesized via microwave irradiation method using two different solvents [N,Ndimethylformamide (DMF) and ethylene glycol (EG)] and two solvent mixtures [N,N dimethylformamide/water (DMF/W) and ethylene glycol/water (EG/W)]. The effect of different solvent systems on the properties of Bi2S3 samples were investigated using XRD, FESEM, EDS, XPS, UV and FTIR analysis. The XRD analysis revealed that the orthorhombic phase of increasing intensities was observed. The microscopic analysis showed that the various shapes of Bi2S3 nanostructures were obtained by changing the solvent combinations. Long nanowires and nanorods with an average length of 250 nm formed when DMF and DMF/W were used as solvents. The synthesized Bi2S3 in EG and EG/W promoted the fabrication of novel nanoflowers composed of thick nanosheets with an average breadth of 755 nm and a honeycomb shape. The EDS and XPS results confirm the purity and the presence of the Bi and S. The N2 adsorption-desorption isotherm studies revealed that the specific surface area of the Bi2S3 sample (EG/W) is 42.82 m2g-1using Brunauer-Emmett-Teller (BET). The UV-Vis absorption spectra revealed the optical properties of all Bi2S3 samples. The FTIR spectra showed the functional groups of the Bi2S3 nanostructures. Among the prepared samples, the Bi2S3 nanostructure obtained in the ethylene glycol/water exhibited the highest photocatalytic activity and achieved 95.18% degradation efficiency of methylene blue (MB) dye after 120 minutes. The MB photodegradation was determined to follow a pseudo-first-order kinetic model, with a rate constant of 0.02271 min-1 being the highest. After three cycles, the Bi2S3(EG/W) nano photocatalyst showed excellent reusability and stability.

Solvent Mediated Interactions on Alkene Epoxidations in Ti-MFI: Effects of Solvent Identity and Silanol Density

Selective alkene oxidation rates within zeolite pores reflect differences in contributions from thermodynamic nonidealities introduced by noncovalent interactions at solid–liquid interfaces and spatial constraints enforced by the zeolite topology. Epoxidation turnover rates for 1-hexene in Ti-MFI zeolite differ by 1000-fold across 10 combinations of solvents, including alcohols and acetonitrile, over Ti-MFI with distinct silanol defect densities. Solvent mediated noncovalent interactions persist across an extended binding environment that influences the stability of epoxidation transition states. Apparent activation enthalpies (ΔHApp⧧) and entropies (ΔSApp⧧) span 80 kJ mol–1 and 200 J mol–1 K–1, respectively, with the most positive values for both appearing in methanol. Hydrophilic (i.e., (SiOH)x defect rich) Ti-MFI-OH catalysts in methanol give the greatest turnover rates because entropic gains associated with the disruption of hydrogen-bonded networks of intrapore methanol and water dominate activation free energies. In situ infrared spectra show that the adsorption of 1,2-epoxyhexane to Ti sites disturbs the equilibrium solvent structure within pores in ways that reflect the density of the hydrogen bond donor and acceptors near active sites. This interpretation agrees with measured enthalpies for adsorption of 1,2-epoxyhexane to Ti active sites within solvent filled pores that correlate with ΔHApp⧧ across solvent and catalyst combinations. The displacement of solvent molecules and the associated rupture and formation of hydrogen bonds among solvents, pore walls, and nearby reactive molecules during catalysis and adsorption events incur substantial excess contributions that govern the reaction rates and barriers. These realizations explain the particular success of alkene epoxidations in mixtures of H2O2 and methanol over hydrophilic forms of Ti-MFI in industrial processes (e.g., the hydrogen peroxide–propylene oxide process). These findings demonstrate the gains achieved by appropriately pairing organic solvents with microporous catalysts to manipulate the intrinsic kinetics of reactions and the thermodynamics of adsorption at solid–liquid interfaces.

The role of quantum-chemical descriptors and sigma-profile overlapping of different co-solvents on tuning ethanolic extraction of soybean oil

Co-solvents can significantly improve ethanol efficiency in vegetable oil extraction, making their use a viable, cost-effective, and sustainable alternative to conventional solvents. The challenge, however, is to understand the complex interactions between the solvents and how this can affect the yield and quality of the extracted oil. In this study, the COnductor-like Screening Model with Segment Activity Coefficient and Hansen solubility parameters were combined and used to optimize soybean oil extraction using ethanol along with seven different co-solvents. In parallel, an experimental approach was carried out to verify the accuracy of the models. Both theoretical and empirical results indicated that the oil extraction yield decreased as the co-solvent polarity increased. The best performance in solubilizing non-polar lipids was observed for the mixture of 10 wt% of p-cymene, a non-polar solvent, with 90 wt% ethanol, reaching a yield of 24.35 g/100 g. According to the thermodynamic analysis, the effects of polarity weigh heavily on the standard entropy, which rules the driving force of mass transfer during the extraction. The interaction mechanisms were carefully investigated employing quantum mechanical calculations, revealing how the differences in chemical potential (μ), hardness (η), and electrophilicity (ω) underlie the macroscopic results and rule the efficiency obtained for different solvent ratios and combinations.

Phytochemical Composition and Anti-Motility Effects of Napoleonae imperialis Methanol Crude Leaf Extract and Fractions in Rats

Background: Extracts from that Napoleonae imperialis leaves have traditionally been used to treat wounds and diarrhoea in south east Nigeria.&#x0D; Aim: The present study was carried out to evaluate following scientific principles, the phytochemical composition and anti-motility effect of leaf extract and fractions prepared from the plants in experimental rats.&#x0D; Methods: Crude extract was prepared from the plant’s leaves and was subjected to phytochemical and acute toxicity tests. Thereafter, the extract was fractionated using column and thin layer chromatographic techniques. Anti-motility effect of the crude extract and fractions was evaluated using 80 rats assigned to 16 groups of 5 rats each. While group 1 served as control and group 2 was treated with Loperamide (0.5 mg/kg), groups 3-16 were treated with specific dose levels of the crude extract or fraction before charcoal meal 30 minutes after treatments. The animals were sacrificed in a further 30 minutes to assess the extents of movement of the charcoal meal along the gastrointestinal tract.&#x0D; Results: Alkaloids (31.09 +0.44 mg/100 g) were the most abundant phytochemical identified in the crude extract and was followed by flavonoids (17.19± 0.90 mg/100 g). Others were saponins (9.61±0.12 mg/100 g), tannins, (3.23±0.06 mg/100 g), phenolics (8.83±0.41 mg/100 g), steroids (5.24±0.10 mg/100 g), terpenoids (2.58±0.11 mg/100 g) and cardiac glycosides (4.95±0.08 mg/100 g). Results of acute toxicity (LD50) test showed no mortality nor obvious signs of toxicity, even at an oral dose of 5000 mg/kg in rats. Results of the anti-motility studies showed that Napoleonae imperialis crude extract and fractions significantly inhibited charcoal meal transit in rat’s gastrointestinal tract with 500 mg/kg of the extract producing an inhibitory effect of 51.44±3.53%. A repeat of the test on chromatographic fractions of the extract showed that fraction 5 had the highest anti-motility effect having produced an inhibitory effect of 87.70±6.04% on intestinal motility.&#x0D; Conclusion: Our findings have shown that Napoleonae imperialis leaves contain pharmacologically active components with antidiarrhoeal activities and may be the reason for its antidiarrheoal application in traditional medicine. The observed effects of the extract may be due to its flavonoids and tannins contents and may be via the anticholinergic and osmotic pathway. Solvent combination for fraction 5 may be the most ideal for higher anti-motility effects. More work is required to further establish these findings.

Synthesis of Some Distinct Curcumin-Based Pyrano [2,3-D] Pyrimidines with Barbituric Acid, Cinnamaldehyde, and Benzaldehyde

Curcumin is a powerful radical oxygen scavenger. The modification of of curcumin’s α, β-unsaturated 1,3-diketone moiety can be carried out to improve its physicochemical stability and functionality. This research aimed to conduct a modification of curcumin structure and to study the antioxidant activity of the modified curcumin-based compound. The modified curcumin made from a combination of benzaldehyde and cinnamaldehyde, using barbituric acid and combination of citric acid as catalyst and ethanol as solvent. The combination of ethanol solvent and 20 mmol% citric acid catalyst produce the highest yield of curcumin product which has a yield of 99.3581±0.2873% and was chosen as the best combination for the next modification using different β-diketone compounds. In the following stage, the mixture was reacted with either benzaldehyde or cinnamaldehyde. Yield, TLC, and antioxidant activity parameters were assessed for all modified products and were accompanied by their characterization using UV-Vis spectrophotometry. This study showed that curcumin cinnamaldehyde had a yield of 47.4831±2.7032%, a maximum wavelength of 416 nm, and antioxidant activity of IC50 18.2130±2.8766 mg/L with a molecular mass of 594 m/z. Keywords: antioxidant activity, benzaldehyde, cinnamaldehyde, curcumin, dimedone, modification

Low nitrogen and high value hydrochar preparation through co-hydrothermal carbonization of sludge and saw dust with acid/alcohol assistance

High hydrothermal temperature and solid-N enrichment were the key issues during co-hydrothermal carbonization (co-HTC) of sludge and lignocellulose biomass. The technology of acid-alcohol assisted co-HTC was proposed and the relevant reaction mechanisms were investigated in this study. The results showed that acetic acid and ethanol promoted the Maillard and Mannich reaction respectively at 453 K through catalytic degradation of different organics. Above 483 K, acetic acid contributed to deamination and reduced solid-N by 9.18%, but there was no decrease in yield because acetic acid participated in hydrochar formation by repolymerization. Ethanol preferred to increase production by 5.82% without extra solid-N enrichment, promoting NH4+-N transformation into quaternary-N with more organic groups substitution. Solvent mixture had best performance on dehydration, carbonization and denitrification reaction to upgrade hydrochar fuel quality. The hydrochar obtained was more approach to lignite with high fixed carbon and heating value as well as low nitrogen content. Thus the fuel property and substance composition could be selected by adjusting the combination of hydrothermal temperature and organic solvent.

Charakterisierung von Fermentationsaromen mittels gaschromatographischer Techniken

Charakterisierung von Fermentationsaromen mittels gaschromatographischer Techniken