C12 Alkyl Research Articles

Aggregation Characteristics of Biobased Anionic Surfactant, Hydroxy Alkane Sulfonate in Aqueous CaCl2 Solutions: Vesicle and Supported Bilayer Formation.

Vesicles are known to spontaneously adsorb onto solid-liquid interfaces and to form supported bilayers in aqueous solution. Cationic surfactants have typically been used to generate supported bilayers because solid surfaces in water are often negatively charged. The present study investigated the aggregation behavior of an anionic surfactant, hydroxy alkane sulfonate having a C18 alkyl chain (C18HAS) in aqueous CaCl2 solutions. These assessments were performed by acquiring data related to equilibrium surface tension, the solubilization of an oil-soluble dye, UV-visible transmittance, pyrene fluorescence and dynamic light scattering together with freeze-fracture transmission electron microscopy observations. The results suggest that C18HAS can form vesicles in aqueous CaCl2 solutions under certain surfactant concentrations. Specifically, this aggregation behavior is greatly affected by C18HAS/CaCl2 molar ratio. At the C18HAS/CaCl2 molar ratio is less than an equivalence point (that is, less than 2:1), phase separation occurs with the formation of a vesicle above solubility limit of the C18HAS Ca salt. On the other hand, in the case that the C18HAS/CaCl2 molar ratio is above an equivalence point (that is, above 2:1), the Na salt of C18HAS forms micelles above the critical micelle concentration (cmc), causing solubilization of vesicles. Analyses by high-speed atomic force microscopy demonstrated that the C18HAS vesicles can spontaneously form a supported bilayer on a negatively charged mica surfaces, similar to the behavior of cationic surfactant vesicles, even though C18HAS is an anionic surfactant. These results suggest that C18HAS could serve as a detergent component but also as a surface modifier when the C18HAS/CaCl2 molar ratio is optimized.

Seasonal variation and origins of C1–C5 alkyl nitrates: A year-long study at a Hong Kong coastal site

Alkyl nitrates (RONO₂) are key reactive nitrogen compounds with significant impacts on local and regional air quality. The concentrations of alkyl nitrates can vary significantly across different regions, especially in areas with varying levels of human activity. Long-term observation of alkyl nitrates is necessary to assess the intensity of photochemical reactions and the contributions from different sources. In this study, we present the first continuous year-long monitoring results of eight alkyl nitrates via whole air sample collection and GC-MSD/ECD analysis at a coastal site in Hong Kong. Source apportionment analysis via positive matrix factorization (PMF) revealed distinctive seasonal variations in the source contributions for the eight alkyl nitrate species. Furthermore, increased contributions from biomass combustion were found in autumn and winter, while marine emissions primarily influenced methyl nitrate levels during summer. Our study highlights the significant impact of biomass burning from inland areas on photochemical pollutants in Hong Kong. Cross-regional cooperation in the Greater Bay Area (GBA) is necessary for more comprehensive management of secondary photochemical pollution.

Synthesized Bis-Triphenyl Phosphonium-Based Nano Vesicles Have Potent and Selective Antibacterial Effects on Several Clinically Relevant Superbugs.

The increasing emergence of multidrug-resistant (MDR) pathogens due to antibiotic misuse translates into obstinate infections with high morbidity and high-cost hospitalizations. To oppose these MDR superbugs, new antimicrobial options are necessary. Although both quaternary ammonium salts (QASs) and phosphonium salts (QPSs) possess antimicrobial effects, QPSs have been studied to a lesser extent. Recently, we successfully reported the bacteriostatic and cytotoxic effects of a triphenyl phosphonium salt against MDR isolates of the Enterococcus and Staphylococcus genera. Here, aiming at finding new antibacterial devices possibly active toward a broader spectrum of clinically relevant bacteria responsible for severe human infections, we synthesized a water-soluble, sterically hindered quaternary phosphonium salt (BPPB). It encompasses two triphenyl phosphonium groups linked by a C12 alkyl chain, thus embodying the characteristics of molecules known as bola-amphiphiles. BPPB was characterized by ATR-FTIR, NMR, and UV spectroscopy, FIA-MS (ESI), elemental analysis, and potentiometric titrations. Optical and DLS analyses evidenced BPPB tendency to self-forming spherical vesicles of 45 nm (DLS) in dilute solution, tending to form larger aggregates in concentrate solution (DLS and optical microscope), having a positive zeta potential (+18 mV). The antibacterial effects of BPPB were, for the first time, assessed against fifty clinical isolates of both Gram-positive and Gram-negative species. Excellent antibacterial effects were observed for all strains tested, involving all the most concerning species included in ESKAPE bacteria. The lowest MICs were 0.250 µg/mL, while the highest ones (32 µg/mL) were observed for MDR Gram-negative metallo-β-lactamase-producing bacteria and/or species resistant also to colistin, carbapenems, cefiderocol, and therefore intractable with currently available antibiotics. Moreover, when administered to HepG2 human hepatic and Cos-7 monkey kidney cell lines, BPPB showed selectivity indices > 10 for all Gram-positive isolates and for clinically relevant Gram-negative superbugs such as those of E. coli species, thus being very promising for clinical development.

Mesomorphism, high-contrast negative fluorosolvatochromism and photoinduced fluorescence conversion of thienylcyanostyrene-pyridinium salts

Novel thienylcyanostyrene and pyridinium-based luminescent ionic liquid crystals (ILCs) characterized with different length of N-alkyl chains (N–C3H7 and N–C8H17) and different size of counter anions (Br−, BF4−, PF6− and Tf2N−) on pyridinium moiety have been synthesized. The chemical modifications of N-alkyl chains and counter anions are easily achieved via pyridine alkylation followed with further ion exchanges, which played a key role in tuning supramolecular self-assembly of these ILCs. The compounds with shorter N–C3 alkyl chain (E-CTPC3X, X = Br−, BF4−, PF6− and Tf2N−) can self-assemble into 3D cubic phase or 2D hexagonal columnar phase depending on the size of counter anion, while the analogues with longer N–C8 alkyl chain (E-CTPC8X, X = BF4− and Tf2N−) only result smectic A phases. Moreover, the prolongation of the N-alkyl chain or enlargement of counter anion could significantly decrease the clear points of LC phases avoiding the thermal decomposition at high temperature, whereas introducing counter anions such as BF4−, PF6− that can form hydrogen bonds have stabilized the LC phases. The notable negative fluorosolvatochromism and the photoinduced fluorescence conversion with high-contrast of these ILCs were observed using UV–vis absorption and photoluminescence (PL) spectra, and was further analyzed by dynamic 1H NMR. These ILCs had been used as dopant to modify the n-Si/PEDOT:PSS heterojunction solar cells (HSCs) with 2 fold hole mobility (μhole) enhancement of the PEDOT:PSS layer.

Preparation and chromatographic evaluation of 9-oxa-10-phosphophenanthrene 10-oxide bonded phenyl stationary phase and investigation of its retention mechanism through nuclear magnetic resonance spectroscopy

BackgroundIn reversed-phase liquid chromatography, the C18 alkyl bonded phase, as the primary stationary phase, is widely used in pharmaceutical and food analysis. The phenyl bonded phase often serves as a complementary choice to the C18 phase to enhance the separation performance of specific categories of compounds. However, both C18 and the currently available phenyl bonded phase chromatography columns show room for further optimization in improving the separation efficiency of specific compound classes, such as dihydroflavonoids. Additionally, the potential role and impact of introducing phosphorus groups into chromatographic stationary phases have not been fully explored, indicating a promising direction for research. ResultsIn the present work, we prepared a novel phenyl stationary phase by bonding 9-oxa-10-phosphaphenanthrene 10-oxide onto silica gel. The obtained material was characterized by scanning electron microscopy, fourier transforms infrared spectroscopy, and elemental analysis. The results show that 9-oxa-10-phosphaphenanthrene 10-oxide was successfully bonded on the silica surface with a load of 3.90 %. Further chromatographic characterization in high-performance liquid chromatography exhibited high column efficiency (40,792 plates m-1 for the determination of biphenyl) and good stability (RSD of 0.28 %∼5.38 %). Moreover, we made a detailed study of the column separation mechanism by nuclear magnetic resonance spectroscopy titration experiment. Comparing to commercial phenyl column, the proposed stationary phase showed shorter retention time and higher throughput. In addition, the stationary phase has a strong ability to separate multiple types of compounds, which provides a new strategy for the separation of complex samples, such as active ingredients in traditional Chinese medicine. SignificanceWe have developed a novel phenyl column and conducted a comprehensive examination of its chromatographic performance, demonstrating excellent separation capabilities and high efficiency for both nonpolar and moderately polar aromatic compounds. Additionally, we explored the impact of phosphorus-containing groups on the separation performance of chromatographic stationary phases.

SYNTHESIS OF POLYACRYLAMIDE HYDROGELS WITH PORPHYRIN FRAGMENTS IN THE SIDE CHAIN IN THE PRESENCE OF IMIDAZOLIUM IONIC LIQUIDS

The acrylamide hydrogels containing the porphyrin fragments have been obtained by radical polymerization in a solution. The synthesis has been carried out in the presence of imidazolium ionic liquids with length of the alkyl substituent in the imidazolium ring from C4 to C8. The influence of the used ionic liquids on the structure and some properties of the resulting porphyrin-containing acrylamide hydrogels has been established. The addition of an ionic liquid with a different length of the alkyl substituent into the reaction system can influence the structural changes that occur with the porphyrin comonomer during copolymerization with acrylamide. The formation of bacteriochlorin-like structures is inhibited in the presence of an ionic liquid in the reaction medium. This effect is most noticeable when using an imidazolium ionic liquid with a C8 alkyl substituent length. Hydrogels synthesized in the presence of ionic liquids have lower specific surface area compared to ones obtained without the use of ionic liquids. The lowest specific surface area values were shown by hydrogels synthesized using 1-octyl-3-methylimidazolium bromide. It was also found that the introduction of ionic liquid into the reaction mixture can contribute to both increase and decrease in the numerical values of the sorption characteristics of the resulting hydrogels, depending on the length of the alkyl substituent in the imidazolium ring and a porphyrin : acrylamide ratio. Hydrogels synthesized using 1-hexyl-3-methylimidazolium bromide and 1-octyl-3-methylimidazolium bromide at an initial porphyrin : acrylamide ratio of 1:20 have the highest degree of swelling. Varying the ratio of the initial monomers and the structure of the imidazolium ionic liquid during the copolymerization process allows to control the physicochemical characteristics of the resulting porphyrin-containing hydrogels, which can be useful for solving various applied problems. For citation: Pechnikova N.L., Smirnov A.S., Lyubimtsev A.V., Aleksandriiskiy V.V., Ageeva T.A. Synthesis of polyacrylamide hydrogels with porphyrin fragments in the side chain in the presence of imidazolium ionic liquids. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 6. P. 73-79. DOI: 10.6060/ivkkt.20246706.7053.

Tailored lipid crystallization in confined microparticle domains through alkyl chains infiltration from cellulose nanofiber surfactants

Through this study, we show that hydrophobically modified cellulose nanofibers can substantially influence the subcell crystallization of ceramide-based lipids within confined particle domains. We demonstrate that C18 alkyl chain-conjugated bacterial cellulose nanofibers (BCNFC18) can armor ceramide (Cer)/stearyl alcohol (SA) lipid crystal phases to form ceramide-based lipid microparticles (CerMPs). X-ray diffraction measurements revealed that by armoring CerMPs with BCNFC18, lipid crystal structures could be changed from the β subcell to β’ subcell. Less generation of β subcells within a densely packed lipid crystal structure is critically important to confine the growth of Cer/SA lipid crystals within a microparticle domain. By performing energy calculations and interfacial rheology analysis, we found that the alkyl chains of BCNFC18 infiltrated the CerMP peripheries. We demonstrate through this study that the alkyl chains of BCNFC18 can associate with the highly crystalline Cer/SA crystal phase of a lipid, thereby strengthening the interface between the lipid and the BCNFC18. The study findings highlight the importance of engineering nanoscale fiber surfactants capable of alkyl chain infiltration. These surfactants can be used to prepare crystallizable active ingredients in a feasible and diverse manner for applications in the pharmaceutical, food, and cosmetic industries.

Self-Assembly of Wheel-Shaped Nanographdiynes and Self-Template Growth of Graphdiyne.

Graphdiyne (GDY) multilayers show stacking-style-dependent physical properties; thus, controlling the stacking style of nanostructures is crucial for utilizing their electrical, optical, and transport properties in electro-optical devices. Herein, we report the assemblies of nanographdiynes decorated with substituents with different steric hindrances to adjust the stacking style. We show that the π-stacked aggregates were influenced by peripheral substituents and the substrate. Steric hexaterphenyl-substituted nanoGDY scaffolds led to dimer structures stacked in the AB-3 configuration with a twist angle of 26.01° or the AB-1 configuration with an in-plane shift along one diyne link. With the interval replacement of steric substituents with long C12 alkyl chains, nanoGDYs were stacked in the AB-2 configuration to decrease the steric congestion, eventually leading to one-dimensional (1D) nanofibrous aggregates. Self-assembly in the presence of substrates can result in ABC-stacked nanoGDYs, which endowed us with the possibility of using nanoGDY as the template for GDY growth in a homogeneous reaction. High-resolution transmission electron microscopy (HRTEM), powder X-ray diffraction (PXRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and near-infrared-ultraviolet-visible (NIR-UV-vis) absorption spectroscopy indicate that the crystalline GDY prepared in this way is a 1.18 eV bandgap semiconductor.

Synthesis, Characterization and In Vitro Anti-cancer Properties of Cationic Gemini Surfactants with Alkyl Chains in Human Breast Cancer

Gemini surfactants have unique advantages in various industries such as detergents, cosmetics, paints, and pharmaceuticals due to their versatile hydrophilic-lipophilic balance. Three novel cationic surfactants, derived from alkyl alcohol and epichlorohydrin, featuring multi-alkyl multiple quaternary-ammonium salts, were synthesized with the order of C4 > C6 > C8 alkyl groups. The structure of the synthetic compounds was determined using FTIR and 1H-NMR analysis. The anti-cancer properties of the Gemini surfactants were determined with the MCF-7 breast cancer cell line, using the MTT cytotoxicity assay. We found an increase in alkyl groups (C4 > C6 > C8), indicating that larger alkyl groups contribute to improved surface qualities. The compounds showed improved surface qualities and reduced critical micelle concentration (CMC). In addition, The results showed the significant anti-cancer potential of compound B1 on the breast cancer cell line. In comparison to compounds B2 and B3, the highest inhibition was observed at concentrations from 25 to 400 µg/mL, demonstrating 26.8% to 4.3% and 32% to 4.7%, inhibition, respectively.

One-step site-specific S-alkylation of full-length caveolin-1: Lipidation modulates the topology of its C-terminal domain.

Caveolin-1 is an integral membrane protein that is known to acquire a number of posttranslational modifications upon trafficking to the plasma membrane. In particular, caveolin-1 is palmitoylated at three cysteine residues (C133, C143, and C156) located within the C-terminal domain of the protein which could have structural and topological implications. Herein, a reliable preparation of full-length S-alkylated caveolin-1, which closely mimics the palmitoylation observed in vivo, is described. HPLC and ESI-LC-MS analyses verified the addition of the C16 alkyl groups to caveolin-1 constructs containing one (C133), two (C133 and C143), and three (C133, C143, and C156) cysteine residues. Circular dichroism spectroscopy analysis of the constructs revealed that S-alkylation does not significantly affect the global helicity of the protein; however, molecular dynamics simulations revealed that there were local regions where the helicity was altered positively or negatively by S-alkylation. In addition, the simulations showed that lipidation tames the topological promiscuity of the C-terminal domain, resulting in a disposition within the bilayer characterized by increased depth.

Wood Esterification by Fatty Acids Using Trifluoroacetic Anhydride as an Impelling Agent and Its Application for the Synthesis of a New Bioplastic.

Fatty acids (FA) and their derivatives with long alkyl chain structures are good candidates for wood esterification to confer thermoplastic properties to wood. Nevertheless, they do not react easily with hydroxyl groups of wood. In this study, we investigated the reactivity of wood with various fatty acids of different chain lengths using trifluoroacetic anhydride (TFAA) as the impelling agent in various reaction conditions. Generally, the esterification of fatty acids without solvents resulted in higher Weight Percentage Gain (WPG) and ester content than the reaction in the presence of CH2Cl2. The esterification reaction could be performed effectively at room temperature, though an increased reaction temperature provoked degradation of the esterified wood. WPG of 67% was obtained for the C3 and 253% for the C16 alkyl chain analogs, respectively. Nevertheless, the ester content was fairly uniform, with values between 10.60 and 11.81 mmol ester/gram of wood for all chain lengths. A higher quantity of reagent led to higher ester content, which tended to stabilize after a ratio of 1:4 wood and TFAA/FA. The esterification reaction was performed rapidly, with an ester content between 7.65 and 9.94 mmol ester/gram of wood being achieved only after 15 min of reaction. Fourier transform infrared spectroscopy (FTIR) analysis was performed to confirm the drastic chemical changes of wood before and after esterification. Morphological observation by scanning electron microscope (SEM), softening measurement by thermomechanical analysis (TMA), and contact angle measurements demonstrated the possibility of esterified spruce wood being applied as a new bioplastic.

Synthesis of High Molecular Weight Biobased Aliphatic Polyesters Exhibiting Tensile Properties Beyond Polyethylene.

Synthesis of high molecular weight polyesters prepared by acyclic diene metathesis (ADMET) polymerization of bis(undec-10-enoate) with isosorbide (M1), isomannide (M2), and 1,3-propanediol (M3) and the subsequent hydrogenation have been achieved by using a molybdenum-alkylidene catalyst. The resultant polymers (P1) prepared by the ADMET polymerization of M1 (in toluene at 25 °C) possessed high Mn values (Mn = 44400-49400 g/mol), and no significant differences in the Mn values and the PDI (Mw/Mn) values were observed in the samples after the hydrogenation. Both the tensile strength and the elongation at break in the hydrogenated polymers from M1 (HP1) increased upon increasing the molar mass, and the sample with an Mn value of 48200 exhibited better tensile properties (tensile strength of 39.7 MPa, elongation at break of 436%) than conventional polyethylene, polypropylene, as well as polyester containing C18 alkyl chains. The tensile properties were affected by the diol segment employed, whereas HP2 showed a similar property to HP1.

Effect of cation hydrophobicity in dicamba-based ionic liquids on herbicide accumulation and bioavailability in soil

One of the main environmental problems due to using herbicides in agriculture is their mobility and leachability from crop fields. Using an ‘ionic liquid’ strategy, we set out to see if it was possible to increase the hydrophobicity of the soluble, easily leached anionic herbicide, dicamba, by combining it with a cation exhibiting increased hydrophobicity, through the incorporation of a C8, C10, C12 and C14 alkyl chain into the structure of naturally derived choline. Hydrophobic modifications of the choline cation were quantitatively sorbed in agricultural soil, posing a long-term danger of accumulation. In addition, the possibility of negative effects on microorganisms, as well as plant germination and development were noted for all tested ionic liquids. Nevertheless, the parameters Kd (0.7–0.8 [L/kg]), Koc (54–58 [L/kg]) and GUS (4.5–3.5) and LIX (0.34) determined for dicamba clearly indicated that this herbicide functions in the soil independently of the cation with which it was originally paired in the ionic liquid. These observations are consistent with the absence of intermolecular interactions between ionic protons, confirmed by the 1H–1H NOESY spectra. The multi-level analysis of ionic liquids, containing herbicidal anion, and the subsequent interactions showed that they are not a new and distinct group of emerging contaminants, but a mixture of known cations and anions that function independently of each other in the environment.

Arginine Gemini-Based Surfactants for Antimicrobial and Antibiofilm Applications: Molecular Interactions, Skin-Related Anti-Enzymatic Activity and Cytotoxicity.

The antimicrobial and antibiofilm properties of arginine-based surfactants have been evaluated. These two biological properties depend on both the alkyl chain length and the spacer chain nature. These gemini surfactants exhibit good activity against a wide range of bacteria, including some problematic resistant microorganisms such us methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa. Moreover, surfactants with a C10 alkyl chain and C3 spacer inhibit the (MRSA) and Pseudomonas aeruginosa biofilm formation at concentrations as low as 8 µg/mL and are able to eradicate established biofilms of these two bacteria at 32 µg/mL. The inhibitory activities of the surfactants over key enzymes enrolled in the skin repairing processes (collagenase, elastase and hyaluronidase) were evaluated. They exhibited moderate anti-collagenase activity while the activity of hyaluronidase was boosted by the presence of these surfactants. These biological properties render these gemini arginine-based surfactants as perfect promising candidates for pharmaceutical and biological properties.

Tungsten minerals flotation with 4-alkoxy benzohydroxamic acid: The structure-performance relationship of its C3 derivatives

To improve the flotation recovery of tungsten minerals, 4-alkoxy benzohydroxamic acids containing C3 alkyl (C3OBs), namely 4-propoxy benzohydroxamic acid (POB), 4-iso-propoxy benzohydroxamic acid (IPOB) and 4-allyloxy hydroxamic acid (AOB), were designed as scheelite and wolframite collectors. The micro-flotation results uncovered that C3OBs exhibited stronger collecting ability towards Pb(Ⅱ)-activated scheelite and wolframite than benzohydroxamic acid (BHA) and the collecting ability of C3OBs was in sequence of POB > IPOB > AOB. The density functional theory (DFT) calculation indicated that the alkoxy oxygen atom of C3OBs contributed to their highest occupied molecular orbital (HOMO), and the HOMO energy followed the order as IPOB > POB > AOB > BHA. The higher HOMO energy, the stronger electron-donating activity. Nevertheless, IPOB didn’t return the highest flotation recovery of tungsten minerals. On the other hand, the hydrophobicity of these four hydroxamate collectors was in sequence of POB > IPOB > AOB > BHA, corresponding to the results of contact angle, micro-flotation and adsorption capacity. Therefore, the hydrophobization of the four hydroxamate collectors played a key role in their flotation performance to the Pb(II)-activated scheelite and wolframite. Moreover, this work offered a new approach for developing superior collectors.

Advances in Nanomaterials Based on Cashew Nut Shell Liquid.

Cashew nut shell liquid (CNSL), obtained as a byproduct of the cashew industry, represents an important natural source of phenolic compounds, with important environmental benefits due to the large availability and low cost of the unique renewable starting material, that can be used as an alternative to synthetic substances in many industrial applications. The peculiarity of the functional groups of CNSL components, such as phenolic hydroxyl, the aromatic ring, acid functionality, and unsaturation(s) in the C15 alkyl side chain, permitted the design of interesting nanostructures. Cardanol (CA), anacardic acid (AA), and cardol (CD), opportunely isolated from CNSL, served as building blocks for generating an amazing class of nanomaterials with chemical, physical, and morphological properties that can be tuned in view of their applications, particularly focused on their bioactive properties.

Synthesis and Evaluation of Antimicrobial Biobased Waxes as Coating Materials.

The objective of this study was to synthesize and evaluate the efficacy of antimicrobial waxes to be used as both physical and biological protection to perishable fruits and vegetables. The existing wax materials used in postharvest coating applications do not provide this antimicrobial functionality. One class of such waxes was obtained by covalently linking quaternary ammonium compounds (QACs) featuring alkyl, benzyl, and stearyl ester hydrophobic side groups to the terminal position of a bromo stearyl ester. A second class was obtained by linking these QACs to the pendant hydroxyl group of an aliphatic diamide made of 12-hydroxystearic acid, stearic acid, and ethylene diamine. In total, six distinct structures having three different QAC groups were synthesized. Compounds containing QACs with C8 alkyl groups exhibited potent inhibition toward the growth of both bacteria and fungi. Notably, the complete inhibition of Penicillium italicum and Geotrichum candidum, two fungi detrimental to the postharvest quality of fruits, as well as the complete destruction of viable cells for Gram-positive and Gram-negative bacteria was observed when these organisms were incubated in contact with QAC waxes or dispersed in an aqueous system at a concentration of 1.0 mM. Comparatively, benzalkonium chloride with an alkyl chain length of 10 carbon can completely inhibit Staphylococcus aureus at a concentration of 1.44 mM. The properties of the attached hydrophobic groups appeared to exert a strong influence on antimicrobial activity presumably due to differences in molecular orientation, size, and differences among microbial cellular structures.

Nickel‐Catalyzed Sequential Dehydrogenation and Cyclization of 2‐Amino(Nitro)‐benzyl Alcohols with Alkyl Alcohols: Synthesis of C‐3‐Substituted Quinolines

AbstractWe herein reported a general and efficient Ni‐catalyzed protocol for sequential double de‐hydrogenative cyclization of 2‐amino(nitro)‐benzyl alcohols with primary alcohols to C‐3‐substituted quinolines releasing water and dihydrogen as by products. As a special highlight, late stage functionalization of cholesterol derivative including chemo‐selective transformations of citronellol, fatty acid derived oleyl alcohol and long chain C4−C14 alkyl alcohols were reported. Initial mechanistic studies including deuterium‐labelling experiments were perform to establish the de‐hydrogenative cyclization.

Ultramicroporous Carbon Molecular Sieve for Air Purification by Selective Adsorption Low-Concentration CO2 and VOC Molecules

The development of an ultramicroporous (<7 Å) adsorbent with a narrow pore distribution for capturing and adsorbing gas molecules has received a lot of attention. In this paper, the commercial carbon molecular sieve (CMS) was used as the precursor, and a carbon molecular sieve (CMS-A-5) with better performance was obtained by activating with potassium hydroxide (KOH). After activation, the ultramicroporous volume increased from 0.163 cm3 g–1 (CMS) to 0.329 cm3 g–1 (CMS-A-5), and the CO2 capacity increased from 42.76 to 71.92 cm3 g–1 at 298 K and 1 bar. The breakthrough experiments demonstrated that the CO2 capture ability of CMS-A-5 increased by ∼9.5 times for the respiratory air containing CO2/O2/N2 (4:20:76) and was easily regenerated and reused. CMS-A-5 was also capable of selectively capturing VOC molecules including benzene, toluene, and C8 alkyl aromatics (BTEX) with a high adsorption capacity at a low pressure. The excellent CO2 and VOC molecule adsorption capacity make CMS-A-5 a promising candidate for selective separation of the gas mixture, in particular, for air purification in confined spaces.

High Internal Phase Emulsion Stabilization through Restricted Interdrop Fusion across Water Drainage Channels

This study introduces a promising approach to stabilize high internal phase emulsions (HIPEs) in which droplets are enveloped by octadecane (C18)-grafted bacterial cellulose nanofibers (BCNFdiC18), which are mainly surrounded by carboxylate anions and hydrophobically modified with C18 alkyl chains. For this purpose, BCNFdiC18, in which two octadecyl chains were grafted onto each of several cellulose unit rings on 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidized BCNFs, was fabricated using the Schiff base reaction. The wettability of BCNFdiC18 was adjusted by controlling the amount of the grafted C18 alkyl chain. Interfacial rheological analysis revealed that BCNFdiC18 enhanced the membrane modulus at the oil-water interface. We figured out that such a resilient interfacial membrane substantially prevented interdrop fusion across the water drainage channel formed between the jammed oil droplets, which was confirmed theoretically using the modified Stefan-Reynolds equation. These findings highlight that the use of surfactants in the form of nanofibers to form a rigid interfacial film plays a key role in hindering the interfusion of the internal phase and the collapse of the emulsion, which is essential for HIPE stabilization.