Molecular Functional Groups Research Articles

Characterization and surrogate formulation of heavy fuel oil

Residual fuel oils have recently garnered attention as promising feedstocks for gasification processes. However, their complex compositions pose challenges for accurate characterization and simulation. This study addresses this issue by formulating a surrogate molecule for heavy fuel oil (HFO) with minimal components, aiming to replicate the average molecular formula and functional groups distribution found in the original fuel. To overcome challenges associated with Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS) detection limits, a distillation process was employed, yielding two fractions: residual distillate (enriched in heavy complex components) and volatile distillate (enriched in light components). Both fractions undergo comprehensive characterization through nuclear magnetic resonance (NMR) spectroscopy, FT-ICR MS for the residual distillate and gas chromatography-mass spectrometry (GC–MS) for the volatile distillate.The study highlights the importance of estimating average molecular weight (AMW) using both fractions to avoid overestimation when relying solely on FT-ICR MS. The developed six-component surrogate, based on elemental analysis, average molecular parameters (AMPs), and AMW of each fraction, demonstrates accuracy in replicating some properties of the original HFO. The surrogate proves effective compared to quantitative structure-property relationship (QSPR) calculations and holds potential for simulating HFO in gasification processes. The molecular design of the surrogate incorporates 1H and 13C NMR data, ensuring similarity in AMPs, AMW, and molecular formula to the target HFO. This comprehensive approach enhances the understanding and application of surrogate molecules for simulating residual oils in gasification processes.

Molecular structure of dissolved organic carbon in a sandy soil receiving contrasting quality organic residues

Decomposing plant residues release plant-derived dissolved organic carbon (DOC) which can be transformed by microorganisms resulting in microbial-derived DOC (DOC biological function). The adsorbability of DOC to mineral surfaces, determined by DOC chemistry (DOC chemical function), can affect its vertical distribution down soil profiles (D). This study investigated the temporal characteristics (T) and functions (bioavailability, adsorbability) of DOC across the profile of a sandy soil by using chemically contrasting quality (Q) residues: 1) high-cellulose rice straw (RS), 2) nitrogen-rich groundnut stover (GN), 3) lignin-rich dipterocarp leaf litter (DP), and 4) medium-nitrogen and -lignin tamarind leaf litter (TM). Soil samples were collected at two depths (0–15 cm and 60–80 cm) two and eight weeks after residue application, and water-extractable DOC was determined. For the first time, the chemical structure of the extracted DOC was characterized using pyrolysis coupled with mid-infrared spectroscopy (Py-MIRS). The dominant functional groups found in all DOC samples were aromatic, carboxyl, and polysaccharide compounds. The interactive effects of Q, T, and D (soil depth) influenced DOC-polysaccharides, with the most pronounced effect observed in the RS treatment during the early stage, indicating that DOC-polysaccharides were mainly plant-derived. Evidence of partial adsorption of DOC-aromatics and DOC-carboxyls was found in topsoils. These high molecular weight-DOC functional groups may have displaced adsorbed polysaccharides, resulting in higher subsoil DOC-polysaccharides than topsoil, especially under DP and TM. During the later stage, topsoil DOC-polysaccharides were negatively related to microbial metabolic quotient (qCO2) (R2 = 0.938). This relationship led to our hypothesis that the dominant source of DOC-polysaccharides, particularly in the TM treatment, was of microbial origin. A novel discovery from this study is that the chemical quality of plant residues, which serve as the source of DOC, determines the origin of the polysaccharides in DOC. This origin transitioned from plant-derived to microbial-derived as decomposition progressed. Importantly, the presented findings were the first of its kind based on a field experiment.

Sustainable and efficient extraction of lignin from wood meal using a deep eutectic system and adsorption of neutral red dye with the extraction residue

In this study, the efficient extraction of lignin from wood meal using a deep eutectic system (DESys) was explored, and the obtained lignin was characterized. The impact of various factors, such as the type of DESys components, extraction time, temperature, water content, and solid-liquid ratio, on the lignin extraction process was systematically investigated. The results indicated that a DESys with a carboxylic acid as the HBD provided the highest lignin extraction efficiency. The obtained lignin was characterized in terms of its molecular weight distribution, elemental composition, functional groups, crystalline structure, and thermal stability. The results showed that the lignin obtained by DESys-based extraction had similar properties to lignin extracted using traditional method. Additionally, the study examined the utilization of the residue left after lignin extraction for the adsorption of cationic pollutants, such as the cationic dye neutral red (NR). The residue was found to contain carboxyl groups, which enabled it to adsorb NR efficiently. The kinetic and thermodynamic models suggested that the adsorption was a chemisorption process. Furthermore, the residue showed selective adsorption for cationic dye over anionic dye. This selectivity was attributed to interactions between the residue's functional groups and the cationic dye molecule. Overall, this study provided a sustainable and comprehensive approach to lignin extraction from lignocellulosic biomass using DESys. It also demonstrated the potential of using the residue from the extraction process for the removal of cationic pollutants from wastewater, showcasing a multi-faceted approach to the valorization of lignocellulosic materials.

Plasma Effects on Properties and Structure of Corn Starch: Characterization and Analysis.

This research investigated the impact of air plasma and high-pressure plasma treatments on corn starch. The resulting samples were characterized by particle morphology, molecular polymerization degree, molecular functional groups, and crystallinity. SEM analysis revealed that plasma treatment altered the surface morphology of corn starch, with variations observed depending on the duration of treatment. UV/Vis spectroscopy results indicated that longer plasma exposure times increased maximum absorbance values with less complete peak shapes. FTIR results demonstrated that plasma treatment disrupted the crystalline structure of starch, resulting in decreased molecular polymerization. Lastly, XRD results showed a proportional relationship between plasma treatment duration and the intensity of the diffuse peak, indicating that prolonged plasma exposure increased the amorphous nature of starch.

Exploring shape memory and self-healing behavior in sodium and zinc neutralized ethylene/methacrylic acid (EMAA) ionomers

Polymeric materials with self-healing and shape memory capabilities have gained increasing attention for their potential applications across various industries. In this study, zinc and sodium ionomers were systematically investigated using a multi-faceted approach, including rheological analysis, Fourier-transform infrared spectroscopy (FTIR), dynamic mechanical thermal analysis (DMTA), X-ray diffraction (XRD), and self-healing and shape memory assessments. Rheological analysis revealed distinct viscosity profiles among the ionomers, with EMAA-Zn 1706 exhibiting higher viscosity at low frequencies and a pronounced thinning behavior across the frequency range. FTIR analysis provided insights into the ionomers' molecular structures and functional groups. DMTA results illuminated the viscoelastic behavior and phase transitions of the ionomers. Peaks in the tan delta curve indicated order-disorder transitions and crystalline melting temperatures, influencing their mechanical properties. XRD patterns revealed low-angle peaks associated with clusters or localized regions within the ionomers. Additionally, characteristic peaks pointed to degrees of crystallinity and ordered packing. Self-healing assessments demonstrated varying healing efficiencies, with values ranging from 40 % to 60 % for EMAA-Zn 9945 and EMAA-Na 2000, while EMAA-Zn 1706 exhibited lower healing efficiency, not surpassing 20 %, attributed to its distinct rheological characteristics. Shape memory experiments were conducted in both torsion and fold-deploy modes, revealing remarkable shape fixations, with all ionomers exceeding 99 % in torsion and 95 % in the fold-deploy method. In aqueous environments, shape memory returns remained above 90 %, underscoring the water's influence on the shape memory effect. The exceptional shape memory performances and varying self-healing efficiencies of these ionomers highlight their versatility and significance in addressing practical challenges, paving the way for tailored materials with promising applications in numerous fields.

Thermoreversible Gelation with Supramolecularly Polymerized Cross-Link Junctions.

Structure and reversibility of cross-link junctions play pivotal roles in determining the nature of thermoreversible gelation and dynamic mechanical properties of the produced polymer networks. We attempt to theoretically explore new types of sol-gel transitions with mechanical sharpness by allowing cross-links to grow without upper bound. We consider thermoreversible gelation of the primary molecules R{Af} carrying the number f of low molecular weight functional groups (gelators) A. Gelators A are assumed to form supramolecular assemblies. Some examples are: telechelic polymers (f=2) carrying π-π stacking benzene derivatives at their both ends, and trifunctional star molecules (f=3) bearing multiple hydrogen-bonding gelators. The sol-gel transition of the primary molecules becomes sharper with the cooperativity parameter of the stepwise linear growth of the cross-links. There is a polymerization transition (crossover without singularity) of the junctions in the postgel region after the gel point is passed. If the gelator A tends to form supramolecular rings competitively with linear chains, there is another phase transition in the deep postgel region where the average molecular weight of the rings becomes infinite (Bose-Einstein condensation of rings). As a typical example of binary cross-links where gelators A and B form mixed junctions, we specifically consider metal-coordinated binding of ligands A by metal ions B. Two types of multi-nuclear supramolecular complexes are studied: (i) linear stacking (ladder) of the sandwich A2B units, and (ii) linear train of egg-box A4B units. To find the strategy towards experimental realization of supramolecular cross-links, the average molecular weight, the gel fraction, the average length of the cross-link junctions are numerically calculated for all of these models as functions of the functionality f, the concentration of the solute molecules, and the temperature. Potential candidates for the realization of these new types of thermoreversible gelation are discussed.

Determination of the ground and excited state dipole moments of ferulic and sinapic acids by solvatochromic effects and density function theory method

Ferulic acid (FA) and sinapic acid (SA) are groups of phenolic acids that belong to the class of hydroxycinnamic acid. Due to their molecular structure and functional groups, these compounds exhibit a wide range of biological activities. In this research, we have determined the dipole moments of these compounds in gas and solvent phases using spectroscopic and computational methods. The change in the dipole moments of FA and SA was calculated by Bakhshiev’s, Kawski–Chamma–Viallet’s, Lippert–Mataga’s, and microscopic solvent polarity functions. The results show that the change in the dipole moment calculated using Lippert–Mataga’s method is higher than that using other methods. This is due to the fact that this method ignores the specific interactions of the solute and solvent as well as the polarizability of the solute molecule. Similarly, the ground and excited-state dipole moments were determined by theoretical quantum chemical calculations using density functional theory (DFT); the results are found to be similar to the experimental ones. In both approaches, the excited dipole moment is greater than the ground state, indicating a significant redistribution of electron densities and being more sensitive to the solvent in the excited state for both molecules. The HOMO-LUMO energy bandgaps calculated in the gas phase for FA and SA are 4.001 and 4.055 eV, respectively. In addition, electron charge density maps, UV–Vis absorption spectra, and oscillator strengths were calculated using the DFT method to obtain general information about the compounds.

Photoluminescence mechanism and optoelectronic responses of Janus pyrene and Janus coronene QDs for OLEDs & nanomedical applications

We carry out a first-principles study on manipulating the optoelectronic and photoluminescence properties of hexagonal and diamond-shaped graphene quantum dots, adopting asymmetric surface functionalization using hydrogen atoms on one side and molecular functional groups (-OH, -COOH, -CHO and -NH2) on the opposite side, leading to Janus quantum dots (JQDs). The results revealed considerable energetic and chemical stability characterizing the studied JQDs. In addition, the gap energy strongly depends on the variation of the shape and functionalization of the surface, giving rise to unexpected behaviour. Interestingly, the inclusion of quasiparticle corrections enhances the electronic character of all configurations, producing results in good agreement with experimental measurements. Optical absorption and excitonic binding energy are significantly altered by the basal plane decoration. At last, energy splitting of the excited states and TDDFT results have confirmed that our structures exhibit tunable photoluminescence from the near ultraviolet to the infrared region of the solar spectrum, making them promising for a new generation of applications.

Synthesis, Structural, Spectroscopic, Fluorescence, and Dielectric Studies of Bis-(4-Aminopyridine)-Zinc(II) Acetate: A Metal-Organic Crystal.

The advancement of crystalline growth and characterization tools allows us to investigate novel nonlinear optical substances suitable for photonic applications. Bis-(4-aminopyridine)-zinc(II) acetate (B4AZA), a metal-organic crystal was produced in this study using the slow evaporation procedure at room temperature. Analytical studies such as X-ray crystallography, Fourier transform infrared (FT-IR), UV-visible (UV-Vis), fluorescence, second harmonic generation (SHG), and dielectric tests were used to characterize the as-grown B4AZA crystals. According to the solubility data, the sample has a positive temperature coefficient of solubility. The crystallographic findings show that the B4AZA crystallized in a monoclinic structure with the P21/n space group. Molecular vibrations and functional groups in the substance were determined using the FT-IR technique. The UV-Vis absorbance and transmittance spectra have shown the wide transparency and minimum absorbance of the B4AZA in the near UV and entire visible regions of the electromagnetic spectrum. The bandgap of the B4AZA has been calculated using the Tauc relation and found to be 4.32eV. The fluorescence spectra have shown a prominent emission peak at 584nm with an excitation wavelength of 280nm. The larger Stokes shift found in the fluorescence spectra is advantageous for practical applications. The SHG study revealed that the powdered B4AZA samples generated a second harmonic output. The dielectric test revealed frequency-dependent changes in the dielectric constant and loss factor. Both the dielectric constant and the loss factor decrease exponentially as frequency increases, reaching low values at higher frequencies. The experimental results illustrate the suitability of the B4AZA crystals for photonic applications.

Photoredox‐Catalyzed Trifunctionalization of 5‐Heteroaryl‐Substituted 1‐Hexenes or 5‐hexenenitriles via Remote Heteroaryl or Cyano Group Migration

AbstractA photoredox‐catalyzed trifunctionalization of 5‐heteroaryl‐substituted 1‐hexenes via remote heteroaryl migration and a photoredox‐catalyzed trifunctionalization of 5‐hexenenitriles via cyano migration are reported. This protocol provides access to a broad scope of CFnR‐containing ketones with high molecular complexity and functional group diversity. The reaction features mild conditions and high chemo‐ and regioselectivities. The success of gram‐scale reactions and the versatility of products in derivative synthesis illustrated the potential value of this transformation in synthetic chemistry.

Preparation and characterization of Eu/ PVP/TPPO/PAN fluorescent film for LED

In this study, a novel red fluorescent materials were prepared by incorporating Eu/PVP/TPPO complexes into PAN substrates. An Eu/PVP/TPPO complex was synthesized by introducing polyvinylpyrrolidone (PVP) into a mixture of europium (Eu) and triphenylphosphine oxide (TPPO). Using a spin-coating technique, highly efficient and thermally stable Eu/PVP/TPPO/polyacrylonitrile (PAN) fluorescent films were prepared. The molecular interactions, surface morphology, functional groups, and elements of the Eu/PVP/TPPO/PAN fluorescent films were characterized by FT-IR, SEM, UV–Vis, and EDS analysis. The thermal stability, fluorescent properties, and chromaticity of the films were also systematically investigated. The results showed that the Eu/PVP/TPPO complex could disperse uniformly in the substrate, and the fluorescent films could emit homogeneous red light. Furthermore, the Eu/PVP/TPPO/PAN fluorescent films had a strong synergistic effect, which increased the fluorescence intensity and produced a purer red light. Based on these findings, a new type of redlight LED device was fabricated by one-step method. Due to its outstanding properties, this film has great potential in the next generation of lighting and display applications.

DFT-Based Calculation of Molecular Hyperpolarizability and SFG Intensity of Symmetric and Asymmetric Stretch Modes of Alkyl Groups.

Vibrational sum frequency generation (SFG) spectroscopy has been extensively used for obtaining structural information of molecular functional groups at two-dimensional (2D) interfaces buried in the gas or liquid medium. Although the SFG experiment can be done elegantly, interpreting the measured intensity in terms of molecular orientation with respect to the lab coordinate is quite complicated. One of the main reasons is the difficulty of determining the hyperpolarizability tensors of even simple molecules that govern their SFG responses. The single-bond polarizability derivative model has been proposed to estimate the relative magnitude of SFG-active hyperpolarizability by assuming that the perturbation associated to each vibration is negligible. In this study, density functional theory was used to calculate the polarizability and dipole derivative tensors of the CH3 stretch mode of CH3I, CH3CH2I, CH3OH, and CH3CH2OH. Then, the hyperpolarizability tensors of symmetric and asymmetric vibration modes were calculated considering the Boltzmann distribution of representative conformers, which allowed us to theoretically calculate their SFG intensities at all polarization combinations as a function of the tilt angle of the CH3 group with respect to the surface normal direction. Then, the ratios of the calculated SFG intensities for the CH3 symmetric and asymmetric stretch peaks used in experimental studies for the CH3 tilt angle determination were compared. This comparison clearly showed that the effect of vibrational coupling among neighboring functional groups is significant and cannot be assumed to be negligible. This study presents new parameters that can be used in determining the average tilt angle of the CH3 group at the 2D interface with SFG measurements as well as limitations of the method.

Enzyme-Assisted Extraction of Ulvan from the Green Macroalgae Ulva fenestrata.

Ulvan is a sulfated polysaccharide extracted from green macroalgae with unique structural and compositional properties. Due to its biocompatibility, biodegradability, and film-forming properties, as well as high stability, ulvan has shown promising potential as an ingredient of biopolymer films such as sustainable and readily biodegradable biomaterials that could replace petroleum-based plastics in diverse applications such as packaging. This work investigates the potential of Ulva fenestrata as a source of ulvan. Enzyme-assisted extraction with commercial cellulases (Viscozyme L and Cellulysin) and proteases (Neutrase 0.8L and Flavourzyme) was used for cell wall disruption, and the effect of the extraction time (3, 6, 17, and 20 h) on the ulvan yield and its main characteristics (molecular weight, functional groups, purity, and antioxidant capacity) were investigated. Furthermore, a combined process based on enzymatic and ultrasound extraction was performed. Results showed that higher extraction times led to higher ulvan yields, reaching a maximum of 14.1% dw with Cellulysin after 20 h. The combination of enzymatic and ultrasound-assisted extraction resulted in the highest ulvan extraction (17.9% dw). The relatively high protein content in U. fenestrata (19.8% dw) makes the residual biomass, after ulvan extraction, a potential protein source in food and feed applications.

Superhydrophobic Nanoparticles: An Efficiently Selective Adsorbent for Surfactant-Like Contaminants from Complex Wastewater Matrices.

Surfactant-like contaminants (SLCs) with distinctive amphiphilic structures have become a global concern in wastewater due to their toxicity and persistency. Despite extensive efforts, achieving efficient and selective SLCs removal remains challenging because of their wide range of molecular weights and complex functional group compositions. Superhydrophobic nanoparticles can potentially tackle this challenge by targeting the long oleophilic chains of SLCs. However, conventional contact angle measurements hinder hydrophobicity characterization and corresponding selectivity research because of the powder morphology of nanoparticles. Herein, the authors offered information regarding the distribution of water molecular probes in surfaces and proposed a quantitative characterization approach based on low-field nuclear magnetic resonance. Through synthesizing superhydrophobic and hydrophilic polydopamine nanospheres with similar morphologies, the selective adsorption potential of superhydrophobic nanoparticles for SLCs is systematically demonstrated. As revealed by the interaction mechanisms, the superhydrophobic surface of nanospheres increased its affinity and selectivity for SLCs adsorption by enhancing hydrophobic interactions. Superhydrophobic modification achieved ten times the adsorption capacity of sodium dodecyl benzene sulfonate, an exemplified surfactant, compared with pristine nanoparticles. By regulated self-polymerization, the superhydrophobic nanospheres are coated onto the surface of a 3D sponge and enable efficient selective SLCs adsorption from highly polluted leachate matrices with long-term stability and reusability.

Evaluation of the effects of L-cysteine addition on the bioleaching of zinc and cadmium from sphalerite flotation concentrate

The primary zinc ore in the world is sphalerite, and roasting-leaching-electrowinning (RLE) is the most typical method of processing. This method has different disadvantages, and bioleaching is an alternative and eco-friendly method for sphalerite treatment. The major drawback of bioleaching is its slow kinetics. In this study, an evaluation of the effects of L-cysteine addition on the bioleaching of zinc and cadmium from a concentrate of sphalerite was investigated in the presence of mixed cultures of mesophilic and moderately thermophilic microorganisms. The results showed that L-cysteine addition increased the dissolution rates of zinc and cadmium while reducing them at higher concentrations. The optimal conditions were achieved by using 0.1 g/L of L-cysteine in mesophilic cultures with zinc recovery of 73.92% and cadmium recovery of 81.45%, respectively. Similarly, zinc recovery was 92.54% in thermophilic cultures, while cadmium recovery was 88.66%. Field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) analyses have detected the formation of jarosite and elemental sulfur on sphalerite surfaces in mesophilic conditions, as well as ammoniojarosite and elemental sulfur in moderately thermophilic conditions. Fourier transform infrared (FTIR) spectroscopy was employed to identify molecular structures and functional groups on the surface of bioleached residues in mesophilic and moderately thermophilic conditions. To assess the environmental risk of residues, a combination of synthetic precipitation leaching procedure (SPLP) and toxicology characteristic leaching procedure (TCLP) methods were used.

Advances in the Application of Artificial Intelligence-Based Spectral Data Interpretation: A Perspective.

The interpretation of spectral data, including mass, nuclear magnetic resonance, infrared, and ultraviolet-visible spectra, is critical for obtaining molecular structural information. The development of advanced sensing technology has multiplied the amount of available spectral data. Chemical experts must use basic principles corresponding to the spectral information generated by molecular fragments and functional groups. This is a time-consuming process that requires a solid professional knowledge base. In recent years, the rapid development of computer science and its applications in cheminformatics and the emergence of computer-aided expert systems have greatly reduced the difficulty in analyzing large quantities of data. For expert systems, however, the problem-solving strategy must be known in advance or extracted by human experts and translated into algorithms. Gratifyingly, the development of artificial intelligence (AI) methods has shown great promise for solving such problems. Traditional algorithms, including the latest neural network algorithms, have shown great potential for both extracting useful information and processing massive quantities of data. This Perspective highlights recent innovations covering all of the emerging AI-based spectral interpretation techniques. In addition, the main limitations and current obstacles are presented, and the corresponding directions for further research are proposed. Moreover, this Perspective gives the authors' personal outlook on the development and future applications of spectral interpretation.

Ammonium Sulfite Slurry from Ammonia-Based Desulfurization Activates Water-Soluble Humic Substances from Lignite: Performance, Application, and Mechanism.

Both ammonium sulfite slurry (ASS) from ammonia-based desulfurization and lignite are waste materials with low value. In this work, an innovative method was developed by applying ASS in lignite activation to produce water-soluble humic substances (WHSs) with a high bioactivity and economic value. The optimal activation method was to mix lignite and ASS at a 4:1-liquid-solid ratio by vortex blender and then oscillate it for 30 min at 25 °C. Compared with that of the unactivated lignite (UAL), the yield of WHSs from activated lignite (AL) increased by 42.72%. WHSs from AL consisted of a large number of aliphatic carbons with low molecular weight and functional groups such as amides, amines, sulfonic acid groups, C-O, and so forth. Moreover, WHSs from AL at lower concentrations (2 mg/L) has a more obvious root-elongation-promoting effect than WHSs from UAL (10 mg/L). Activation experiment with the lignite-related model compounds revealed that ASS caused the breakage of Caliph-O, Caliph-Caliph, and Carom-Caliph linkages between aromatic rings. These findings provide a theoretical basis for the development of green and sustainable technologies for the beneficial reuse of ASS and lignite in agriculture.

Synthesis of tantalum nanoparticles by laser ablation in liquid method and investigating the effect of electric field on the structural properties

In this research, tantalum nanoparticles were prepared by the laser ablation method and the effect of an electric field on their structural properties was investigated. The optical absorption spectra were studied to comprehend the optical properties of nanoparticles. Size and morphology of nanoparticles are illustrated by TEM images. The average size of tantalum nanoparticles is 19 and 45[Formula: see text]nm for synthesized samples without and with electric fields, respectively. By applying an electric field, the morphology of nanoparticles changed from spherical to tangled shapes. XRD analysis showed the crystalline structure of nanoparticles. The investigation of bending and stretching of molecular functional groups and the measurement of the hydrodynamic radius were done by FTIR, RAMAN and DLS analyses, respectively. FTIR, RAMAN, XRD and DLS analyses confirm the structure. EDX spectra confirmed the existence of ingredients. The stability of colloidal is indicated by zeta potential analysis. Photoluminescence spectra reveal nanoparticle properties. As the electric field increases, the size of nanoparticles increased, morphology changes from spherical, and oxidation increases.

Efficient mapping of lignin depolymerization product pools and quantification of specific monomers through rapid GPC-HPLC-UV/VIS analysis

BackgroundGrowing research on lignin depolymerization to functionalized bio-aromatics has necessitated dedicated analysis techniques. However, immense variability in molecular weight and functional groups of the depolymerization products impedes fast analysis of a large number of samples while remaining in-depth enough for catalyst screening or reaction condition optimization. While GPC-HPLC-UV/VIS has been a promising technique, up until now, the information it provides is largely qualitative. By enabling quantification of key monomeric products and through further reduction of overall analysis time, this study aims to increase the potential of GPC-HPLC-UV/VIS for fast and in-depth characterization of lignin depolymerization product pools. ResultsAnalysis of selected samples, isolated from GPC-HPLC-UV/VIS analyses of lignin depolymerization product pools, with gas chromatography (GC) equipped with an Orbitrap high-resolution accurate mass spectrometer (Orbitrap-HR/AM-MS) is successful in identifying the main low monomeric products. Moreover, these identifications are further substantiated through GPC-HPLC-UV/VIS analysis of standards. Furthermore, straight forward quantification of these products directly within GPC-HPLC-UV/VIS is successfully developed with limits of detection ≤0.05 mmol/L, which is at least on par with more complex analysis techniques. Additionally, several different reversed phase columns are assessed to reduce 2nd dimension (2D) time and, hence, overall analysis time while maintaining the possibility for quantification. A reduction in overall analysis time of about 30% as compared to the state-of-the-art is achieved by using a YMC Triart BIO C4 column as 2D. SignificanceThrough the enhancements introduced in this study, GPC-HPLC-UV/VIS emerges as a unique technique for the analysis of lignin depolymerization product pools, which is capable of fast yet sufficiently in-depth analysis of a large volume of samples. This capability is indispensable for catalyst screening and fine-tuning reaction conditions.

TAMOF-1 as a Versatile and Predictable Chiral Stationary Phase for the Resolution of Racemic Mixtures.

Metal-organic frameworks (MOFs) have become promising materials for multiple applications due to their controlled dimensionality and tunable properties. The incorporation of chirality into their frameworks opens new strategies for chiral separation, a key technology in the pharmaceutical industry as each enantiomer of a racemic drug must be isolated. Here, we describe the use of a combination of computational modeling and experiments to demonstrate that high-performance liquid chromatography (HPLC) columns packed with TAMOF-1 as the chiral stationary phase are efficient, versatile, robust, and reusable with a wide array of mobile phases (polar and non-polar). As proof of concept, in this article, we report the resolution with TAMOF-1 HPLC columns of nine racemic mixtures with different molecular sizes, geometries, and functional groups. Initial in silico studies allowed us to predict plausible separations in chiral compounds from different families, including terpenes, calcium channel blockers, or P-stereogenic compounds. The experimental data confirmed the validity of the models and the robust performance of TAMOF-1 columns. The added value of in silico screening is an unprecedented achievement in chiral chromatography.