Aromatic Functional Groups Research Articles

Nitrogen Application Increases Abundance of Recalcitrant Compounds of Soil Organic Matter

Nitrogen (N) fertilization changes both the degradation rate and chemical composition of plant litter and soil organic matter (SOM). We sought to document how N application rates and incorporation of crop straw residues in wheat-rice rotation systems are related to the chemical composition of SOM. Using Fourier transform infrared spectroscopy and C multiple cross-polarization/magic angle spinning nuclear magnetic resonance spectroscopy techniques, we investigated the chemical composition of SOM with incorporation of crop straw residues in a 6-year wheat-rice double-cropping system. Nitrogen fertilizer was applied at the rates of 0, 290, 380, and 470 kg N ha per year along with the incorporation of crop residues into the soil. We found that greater additions of N increased the concentrations of both C and N in the soil. The Fourier transform infrared spectra of SOM indicated that the abundance of aromatic functional groups (~1,628 and ~1,515 cm) and the amide groups (~1,660 and ~1,550 cm) increased in the N-amended treatments compared with the unamended treatment. C multiple cross-polarization/magic angle spinning nuclear magnetic resonance spectroscopy results revealed that the abundance of recalcitrant compounds, including alkyl and aromatic C, increased, whereas labile SOM components, dominated by O-alkyl and anomeric C, decreased with the elevated N application rates. These observations were also reflected in calculated indices of A/O-A aromaticity and hydrophobicity. Our results support the hypothesis that recalcitrant compounds of SOM appeared to be enhanced with the increase of the N application rates to promote crop straw decomposition in the rice-wheat rotation system.

Comparative study of interfacial interaction between aromatic and aliphatic functional group in solder wettability

The effect of using different flux on wettability of Sn-Ag-Cu lead free solder were investigated. In this study, solder paste Sn-3.0Ag-0.5Cu (SAC305) was used by introducing two types of no-clean flux with different ingredients. The solders namely as SAC305-A and SAC305-B respectively. Then, the both solder paste manually printed on printed circuit board (PCB) using stencil printing and then reflowed at 260 °C temperature. Wettability of Sn-Ag-Cu solder using different flux was determined by contact angle measurement using Alicona ® IFM software. Results show the SAC305-A solder alloys have a good and better wettability with lower contact angle compared to SAC305-B. Functional groups of both solder flux was identified by FTIR analysis. Meanwhile XPS analysis was performed in characterizing the studied fluxes. It was found that no-clean flux solder with aromatic functional groups showed lower contact angle value and better wettability than aliphatic contained functional groups.

Application of high resolution NMR (1H and 13C) and FTIR spectroscopy for characterization of light and heavy crude oils

High-resolution nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) spectroscopy experiments were applied to obtain detailed information on the hydrocarbon chemistry of three light and three heavy crude oils. Quantitative fractions of aromatic molecules and functional groups constituting oil hydrocarbons were determined by 13C NMR spectroscopy and comparative analysis of the oil samples with different viscosity, origin and preliminary treatment. SARA composition and some important information about aromaticity, oxidation behavior, branching, aliphaticity and sulfurization of studied oil samples were obtained. Integral characteristics of high-resolution NMR and FTIR spectra have a great potential to study the structure and characterization of light and heavy crude oils, which could substitute present traditional fractionation procedures. Relationships between spectroscopic parameters obtained by high-resolution NMR and FTIR spectroscopy methods and crude oil compositions can be useful for fast prediction of crude oil properties due to different type of treatment, including thermal methods for enhanced oil recovery. Also quantitative proportions of functional groups obtained by NMR and spectral indices obtained by FTIR can be one of the criteria for developing fingerprint approach.

High-resolution NMR study of light and heavy crude oils: “structure-property” analysis

Measurements of three light and one heavy crude oil samples were carried out by high-resolution nuclear magnetic resonance (NMR) spectroscopy methods. Quantitative fractions of aromatic molecules and functional groups constituting oil hydrocarbons were determined, and comparative analysis of the oil samples of different viscosity and origin was done.

Exploring the fate and oxidation behaviors of different organic constituents in landfill leachate upon Fenton oxidation processes using EEM-PARAFAC and 2D-COS-FTIR

In this work, the changes of different organic constituents in landfill leachate were tracked in Fenton oxidation processes with different operation parameters including H2O2 doses, pH, and the ratios of [H2O2]/[Fe] via fluorescence excitation emission matrix – parallel factor analysis (EEM-PARAFAC) and two-dimensional correlation spectroscopy (2D-COS). One tryptophan-like (C1), one fulvic-like (C2), and one humic-like (C3) components were identified in the leachates. The removal behaviors of the individual fluorescent components were dependent upon the operation conditions, suggesting the existence of unique characteristics with respect to the responses to the oxidation mechanisms, which were likely altered by different operation conditions. For all tested conditions, a greater extent of removal was consistently found for C3 versus C1 and C2 except for the relatively high pH ranges (>6.0), in which C2 presented the highest removal rates. 2D-COS combined with synchronous fluorescence spectra exhibited the preferential oxidation sequence in the order of C3 > C1 > C2 with higher H2O2 doses. 2D-COS coupled with Fourier transform infrared (2D-COS-FTIR) showed that aromatic functional groups were initially oxidized, followed by the removal of carboxylic groups and the formation of inorganic functional groups and aldehyde or ketonic groups. Hetero 2D-COS maps further revealed the close association between the aromatic groups and C3, and between the carboxylic groups and C1. This study utilizing 2D-COS provided new insights into the dynamic behavior of heterogeneous landfill leachate in Fenton oxidation processes under varying operation conditions.

Effect of acetone–butanol–ethanol addition to diesel on the soot reactivity

The ability of acetone–butanol–ethanol (ABE) to reduce pollutant emissions has been validated in recent studies. In this study, the effect of addition of ABE (up to 30% by volume) to diesel on the soot oxidation reactivity was investigated to further evaluate the feasibility of increasing the particulate filter regeneration rate. The oxidation activities of soot samples were compared using the average activation energies calculated from the thermal gravimetric curves. It was found that the average activation energies of the ABE-diesel-blends-derived soot are lower than that of diesel-derived soot. The variations in the physical and chemical properties of the soot samples were investigated to determine the parameters that improve the soot oxidation reactivity. Several experimental diagnostic techniques, such as Fourier transform infrared spectroscopy, elemental analysis, X-ray diffraction, and high-resolution transmission electron microscopy, were used to investigate the changes in the functional groups, atomic O/C and H/C ratios, nanocrystallite parameters, and soot nanostructures. With increasing concentration of ABE in diesel, the size of the primary particles, nanocrystallite length, and amount of aromatic CC functional groups in the soot decrease, while the nanocrystallites tortuosity, amount of oxygenated functional groups, and atomic O/C and H/C ratios increase. The changes of these parameters prove the higher reactivity of ABE-diesel-blends-derived soot.

Neem Leaf Extract as a Corrosion Inhibitor on Mild Steel in Acidic Solution

The influence of neem leaf extract on corrosion inhibition of mild steel in 0.1 M HCl solution was studied using the weight loss method. Neem leaf extract which contains the double bond, carbonyl groups, and aromatic rings functional group as shown by the GCMS, phytochemical test, and FTIR analyses is one of the good natural plant extract that can be used as corrosion inhibitor. The weight loss on surface of mild steel at various inhibitor concentrations was determined. The highest inhibition efficiency of 93.24% was achieved using the neem leaf extract as corrosion inhibitor. Adsorption mechanism was investigated using Langmuir, Temkin, and Freundlich isotherms. Inhibitor adherence on the mild steel surface was spontaneous with the negative Gibb’s free energy value obtained. The mixed type adsorption mechanism (physisorption and chemisorption) is proposed for the inhibitor adsorption on mild steel surface. The inhibitor was adsorbed on the mild steel surface through adsorption of the phytochemical components on the surface of mild steel which protects the metal surface from corroding. The corrosion rate decreases from 0.001 to 0.0002MPY with increase in inhibitor concentrations and exposure time.

Investigation on solubility of multicomponents from semi-anthracite coal and its effect on coal structure by Fourier transform infrared spectroscopy and X-ray diffraction

As a sedimentary rock composed of organic carbonaceous matters with different molecular sizes and inorganic minerals, coal can be extracted by organic solvents and dissolved by acids to make chemical compositions and structures changed, thus influencing on the occurrence and migration of coalbed methane (CBM). For the purpose of investigating the impacts of different solvents on coal structure, semi-anthracite coal samples from Huoerxinhe coalmine in the central part of Qinshui Basin were treated by four single solvents (tetrahydrofuran (THF), carbon disulfide (CS2), hydrochloric acid (HCl) and chlorine dioxide (ClO2)), and by combined solvents (an organic solvent and an inorganic solvent with different treatment orders). Then the solubility behaviors of the organic compounds or inorganic matters from coal were investigated and the changes of the functional groups and the microcrystalline structure in coal were addressed using Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The results show the extraction yields of organic solvents are significantly greater than the dissolution yields of inorganic solvents, and the solubility of HCl is relatively higher than that of ClO2. Specifically, main functional groups in coal, including aliphatic, aromatic and oxygen-containing functional groups, have a decline tendency to different degrees under the treatment of organic solvents. Further, main microcrystalline structure parameters increase in vertical direction but reduce in parallel direction of the aromatic carbon network layer with the swelling effect, regardless of an organic solvent or inorganic solvent treatment. Only by the organic solvent treatment, do the d002 values of the basic structure unit of coal appear dramatically enlarged characteristics. Whereas, main functional groups and microcrystalline structure in coal show relatively complex features within the combined solvents treatment because of the phenomenon of pore-blockade, pore-expansion or slight solvent retention. Based on the change characteristics and mechanisms, the chemical structure model of semi-anthracite coal is put forward for providing a reference for the further study of coal structure.

The Effect of Kaffir Lime Leaves Distillation Residue Oleoresin Concentration on Active Paper Packaging Characteristics

Oleoresin of kaffir lime leaves distillation residue still contains some active compounds such as Citronellal, β-Citronellol, and Linalool which potential to incorporated on the active paper packaging. The purposes of this study were to determine the effect of kaffir lime leaves distillation residue oleoresin concentration on the physical characteristics, sensory characteristics, and antimicrobial activity of the active paper packaging incorporated with kaffir lime leaves distillation residue oleoresin and to determine the functional groups of active paper packaging. The concentration of kaffir lime leaves distillation residue oleoresin were varied at 0%, 2%, 4% and 6%. The result showed that the addition of kaffir lime leaves distillation residue oleoresin increased the thickness and moisture content of the paper and decreased the tensile strengths and folding endurances of active paper packaging. The microbial inhibition tends to increase along with the higher oleoresin concentration addition. Aromatic CH group were found at a wavelength of 897.90 cm-1 of on paper packaging with 2% oleoresin indicated as functional aromatic functional group allegedly obtained from the kaffir lime leaves oleoresin.

Pilarization TiO2 onto De-oiled spent bleaching clay using Rarasaponin as surfactant

Synthesis and characterization TiO2 pillared deoiled spent bleaching clay (DSBC) with rarasaponin as surfactant had been done. Activation DSBC have been done with H2SO4 1N, followed by pillarization with TiO2 using rarasaponin as surfactant. Characterization has done with Fourier transform infrared spectroscopy showed the rarasaponin as surfactant was successfully carried out in DSBC with the presence of absorption peak C=O stretching group in a sharp 1720.50 cm-1 wavelength range. As well as the C-CH2 stretching uptake peak is represented on wave number 1462.04 cm−1 and 1033,85 cm−1 for aromatic functional group C=C stretching. After pillared by TiO2, the XRD pattern on DSBC showed new peak appears on 2θ = 27,4460° 36,0850° and 55,3216° and the mineral contain on DSBC is rectorite with dioctahedral mica layer and dioctahedral smectite with ratio 2:1. This molecule have formula Na.Al4(Si, Al)8.O20.(OH)4. H2O. Crystallinty of pillared clay showed 72,5014 % after calcination and there is some Ti suspected on the layer based on SEM.

Increased Potency and Selectivity for Group III Metabotropic Glutamate Receptor Agonists Binding at Dual sites.

A group III metabotropic glutamate (mGlu) receptor agonist (PCEP) was identified by virtual HTS. This orthosteric ligand is composed by an l-AP4-derived fragment that mimics glutamate and a chain that binds into a neighboring pocket, offering possibilities to improve affinity and selectivity. Herein we describe a series of derivatives where the distal chain is replaced by an aromatic or heteroaromatic group. Potent agonists were identified, including some with a mGlu4 subtype preference, e.g., 17m (LSP1-2111) and 16g (LSP4-2022). Molecular modeling suggests that aromatic functional groups may bind at either one of the two chloride regulatory sites. These agonists may thus be considered as particular bitopic/dualsteric ligands. 17m was shown to reduce GABAergic synaptic transmission at striatopallidal synapses. We now demonstrate its inhibitory effect at glutamatergic parallel fiber-Purkinje cell synapses in the cerebellar cortex. Although these ligands have physicochemical properties that are markedly different from typical CNS drugs, they hold significant therapeutic potential.

A Si-rhodamine-based near-infrared fluorescent probe for visualizing endogenous peroxynitrite in living cells, tissues, and animals.

Peroxynitrite (ONOO-) is an extremely powerful biological oxidant and it can react with a wide variety of molecular targets to result in a series of disease states, which has made ONOO- a central biological pathogenic factor. In order to disclose its various pathological events, a large number of fluorescent ONOO- probes have been developed in recent years. Nevertheless, some limitations still remain, such as short excitation and emission wavelengths, long fluorescence response times, and cross-interference caused by other reactive oxygen species (ROS). In this work, a new near-infrared (NIR) fluorescent probe, SiRTA, containing an aromatic tertiary amine functional group and a Si-rhodamine fluorophore, was developed for endogenous ONOO- detection and imaging. The probe exhibits not only a fast, sensitive, and specific fluorescence off-on response toward ONOO- in chemical systems but also excellent imaging ability for endogenous ONOO- in living cells. With the probe, the therapeutic effects of phenolic acid antioxidants in EA.hy926 endothelial cells suffering from ischemia-reperfusion injury and the pathogenesis of diabetes and diabetic nephropathy in pancreatic β-cells and diabetic rats have successfully been evaluated. These results indicate that SiRTA is a potentially outstanding imaging tool for studying the physiological and pathological events of ONOO- and relevant drug therapies.

Identifying Plant Stress Responses to Roxarsone in Soybean Root Exudates: New Insights from Two-Dimensional Correlation Spectroscopy.

Roxarsone (ROX) is an organoarsenic feed additive of increasing interest used in the poultry industry. Soybean responses to ROX stress were investigated in root exudates (REs) using two-dimensional correlation spectroscopy (2D-COS) with fluorescence and Fourier transform infrared spectra. Environmentally relevant ROX concentrations caused negligible toxicity to crop growth and photosynthesis activity but blackened soybean roots at high concentrations. 2D-COS analysis revealed that the protein-like fluorophore and C═C and C═O, aliphatic OH, and polysaccharide C-O-H moieties in soybean REs were most sensitive to ROX stress. Heterospectral 2D-COS results suggested that aromatic, amide I, quinone, ketone, and aliphatic functional groups were the foundational components of protein-like and short-wavelength excited humic-like fluorophores in soybean REs. Carboxyl and phenolic moieties were related to the long-wavelength excited humic-like fluorophore. Overall, 2D-COS combined with molecular-based spectral analysis of REs provided an innovative approach to characterize the physiological responses of crops to contaminants at sublethal levels.

Design, synthesis, and cytotoxicity evaluation of threonine-based galactoceramide with aromatic groups and various fatty-acyl side chains

In galactoceramides, presence of fatty-acyl group on amide moiety or phytosphingosine group is some of the important features that influence the cytotoxicity. Continuous efforts are in progress to modify the fatty-acid moiety and phytosphingosine group present on the galactoceramides to enhance the cytotoxic potential of these compounds. Hence, in the present study, threonine-based β-galactoceramide and its derivatives were prepared by modifying the fatty-acyl group on amide moiety with different fatty-acyl moieties and aromatic acids employing trichloroacetimidate methodology. The structurally related threonine-based ceramide part was synthesized in multi-step process using different reagents. The ceramide part was glycosylated with galactose using trichloroacetimidate as donor. Further, all the synthesized compounds were evaluated for in vitro cytotoxicity against three cancer cell lines and one normal cell line and all the compounds exhibited good to moderate cytotoxicity against all the tested cancer cell lines. In aromatic derivatives, the compound 8i exhibited promising activity against MCF7, A549 and HeLa cancer cell lines with IC50 values of 14.08, 14.78, and 16.70 µM, respectively. In fatty-acid derivatives, two compounds exhibited promising activity, i.e., compound 8m against HeLa with IC50 value 16.34 µM and compound 8n against MCF7 with IC50 value 18.05 µM. Based on structure–activity relationship, aromatic acid derivatives exhibited potential activity as compared to fatty-acid derivatives. Further, the influence of some of the key factors such as spacer chain length between aromatic residue and amide functional group, methoxy substituents on aryl group, terminal unsaturation of fatty acid and branching chain effect on the cytotoxicity are discussed.

Allenols versus Allenones: Rhodium-Catalyzed Regiodivergent and Tunable Allene Reactivity with Triazoles.

2-Pyrrolines and 6-oxo-hexa-2,4-dienals have been prepared through the divergent reactions of 1-benzenesulfonyl-4-aryl-1,2,3-triazoles with functionalized allenes. The rhodium-catalyzed reactions between allenols and 1-benzenesulfonyl-4-aryl-1,2,3-triazoles yielded 2-pyrrolines. This transformation is compatible with the presence of aliphatic, aromatic, heterocyclic, amide, and halogen functional groups. Interestingly, a reactivity switch took place when the allene-tethered alcohol substrate was replaced by its ketone counterpart. When the rhodium-catalyzed reaction of 1-benzenesulfonyl-4-phenyl-1,2,3-triazole was performed with allenones, acyclic 6-oxo-hexa-2,4-dienals were stereoselectively formed as (2Z,4E) isomers.

ANTI-CORROSION PERFORMANCE OF 1,3-BENZOTHIAZOLE ON 410 MARTENSITIC STAINLESS STEEL IN H2SO4

The corrosion inhibition effect of synthesized 1,3-benzothiazole at very low concentrations on 410 martensitic stainless steel in 3[Formula: see text]MH2SO4 solution was studied through potentiodynamic polarization and weight loss measurements. The observation showed that the organic compound performed effectively with average inhibition efficiencies of 94% and 98% at the concentrations studied from both electrochemical methods due to the inhibition action of protonated inhibitor molecules in the acid solution. The amine and aromatics functional groups of the molecules active in the corrosion inhibition reaction were exposed from Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) spectroscopic analysis. Thermodynamic calculations showed cationic adsorption to be chemisorption adsorption, obeying the Langmuir adsorption isotherm. Images from optical microscopy showed an improved morphology in comparison to images from corroded stainless steel. Severe surface deterioration and macro-pits were observed in the uninhibited samples.

Removal of micropollutants from Sakarya River water by ozone and membrane processes.

The removal of some pollutants in the Sakarya River was investigated in this study. Sakarya River located in Turkey flows from the northeast of Afyonkarahisar City to the Black Sea. Nineteen different micropollutants including trihalomethanes (THMs), haloacetic acids (HAAs), endocrine disrupting compound (EDC) and pharmaceuticals personal care product (PPCP) groups, and water quality parameters such as dissolved organic carbon (DOC), ultraviolet absorbance at 254nm wavelength (UV254), hardness, and conductivity values were examined. To remove the micropollutants and improve the water quality, the treatment was performed with ozone, microfiltration (MF), and ultra-filtration (UF) membranes. The highest treatment efficiency was obtained with 1mg/L ozone dosage and UP005 UF membrane. The trihalomethan formation potential (THMFP) and haloacetic acid formation potential (HAAFP) decreased with ozone + membrane at a concentration of 79 and 75%, respectively. After the treatment with ozone + membrane, the concentration of the micropollutants in the EDC and PPCP group remained below the detection limit. It was found that by using only membrane and only ozone, the maximum DOC removal efficiency achieved was 46 and 18%, respectively; and with ozone + membrane, this efficiency increased up to 82%. The results from the High-Pressure Size Exclusion Chromatography (HPSEC) analyses pointed that the substances with high molecular weight were converted into substances with low molecular weight after the treatment. The Fourier Transform Infrared (FTIR) analysis results showed that the aromatic and aliphatic functional groups in water changed after the treatment with ozone and that the peak values decreased more after the ozone + membrane treatment.

Derivation of optimum operating conditions for the slow pyrolysis of Mahua press seed cake in a fixed bed batch reactor for bio–oil production

The effect of pyrolysis temperature, retention time and inert gas (i.e. N2) flow rate on the conversion of Mahua Press Seed Cake (PSC) into bio–oil was studied in a slow pyrolysis fixed bed batch reactor. The optimum operating conditions for the process were derived using a Response Surface Methodology (RSM). It was found that the highest bio–oil yield (49.25wt.%) can be achieved at a moderate temperature of 475°C and a retention time of 45min. As expected, the bio–oil yield was found to be affected by the reaction temperature. In a GC–MS analysis of the bio–oil, major compounds found were 6–octadecenoic acid, octadecanoic acid and free fatty acids (FFAs). The physicochemical properties of a raw PSC and bio–char were studied using bomb calorimeter, elemental analysis, and Fourier Transform Infrared (FT–IR) spectroscopy techniques. The heating value of the pyrolytic bio–oil (31.53MJ/kg) at 475°C was found to be increased by 46% compared to that of raw PSC (21.592MJ/kg). The FT–IR analysis indicates that there was a decrease in the number of OH (hydroxyl), CH (alkanes) and CO (primary alcohol) groups and an increase in the number of CC (aromatics) functional groups with an increase in the pyrolysis temperature. Bio–gas analysis confirmed that, at higher temperatures, higher gas yield with increased CO and CH4 contents was observed. Finally, from the energy balance and economic analysis, it has been confirmed that at the derived optimum operating conditions it is feasible to produce bio–oil from Mahua PSC.

Qualitative and quantitative analysis of oil samples extracted from some Bashkortostan and Tatarstan oilfields based on NMR spectroscopy data

Measurements of crude oil samples by nuclear magnetic resonance spectroscopy were carried out. The quantitative fractions of aromatic molecules and functional groups constituting oil hydrocarbons in several samples were determined and their slight variation from sample to sample was shown. Information on content of general functional groups (tertiary and primary carbon atoms, aromatic cores) and possible presence of olefins or water impurity can be obtained. Basic 1H measurements are rather fast and require several minutes. Experiments on modern high-field spectrometers provide better resolution of overlapping regions in 13C NMR spectra and thus would be more convenient to get detailed information on the amount of different alkyl substituents. Slight but obvious differences were observed between the spectra of the samples taken from different levels of the same oil well.

FLASHCHAIN Theory for Rapid Coal Devolatilization Kinetics. 8. Modeling the Release of Sulfur Species from Various Coals

This modeling study expands FLASHCHAIN theory to interpret the release rates and yields of H2S, COS, and SO2 and the sulfur contents of tar and char from any coal and thereby completes the theoretical framework for the devolatilization of all five major organic elements in any coal. The proposed reaction set accurately interprets a database that represents heating rates from 10 to almost 104 °C/s, temperatures to 1500 °C, contact times to 7 min, and S product distributions from 27 different coal samples representing ranks from lignites to anthracites, albeit with persistent uncertainties on the split between tar S and noncondensable S products. A single distributed-energy reaction with the same parameters for all coals accurately describes the release of H2S from pyrite during primary devolatilization. Additional kinetic rate data on sulfate decomposition under rapid heating is needed to close the analysis for inorganic S species. By associating aliphatic and aromatic sulfide functional groups with labile...