Alkyl Chain Length Research Articles

Simultaneous adjustment on the CO2/oil and CO2/water interface tensions using hydrophilic, lipophilic and CO2-philic surfactants during CO2 flooding to enhance shale oil recovery after hydraulic fracturing

It is an urgent demand to further enhance shale oil recovery after large-scale hydraulic fracturing with a low oil recovery. CO2 flooding technology has been demonstrated to effectively develop shale oil, however, the residual water after hydraulic fracturing can influence the efficiency of CO2 flooding because of the high CO2-water interfacial tension. Here, the hydrophilic, lipophilic and CO2-philic surfactants were investigated to simultaneously adjust the CO2/oil and CO2/water interface tension to accelerate the oil and water flows to enhance shale oil recovery. The results show that the low-carbon alcohol polyoxyethylene polyoxypropylene ether has the hydrophilic, lipophilic and CO2-philic properties. The alkyl chain length and PO groups have great influence on the interfacial tension of CO2-oil, while the presence of EO groups can significantly reduce the interfacial tension of CO2-water. The surfactant of C4EO3PO6 can not only demonstrate the best performance in reducing the interfacial tensions of shale oil-CO2 and water-CO2, but also decrease the minimum miscibility pressure (MMP) of the shale oil-CO2 system to 18.89 MPa from 24.10 MPa. The interfacial tension between water and the CO2 + 1.0 wt% C4EO3PO6 system can be decreased to 6.62 mN/m at 28 MPa and the reduction rate is 56.10 %. The enhancement of surfactants on the extraction effect of CO2 and the mutual diffusion process between CO2 and shale oil or water interface is the major mechanism to decrease the interfacial tensions. Therefore, the addition of surfactant in CO2 can simultaneously decrease the interfacial tensions of CO2-oil and CO2-water and has a potential to enhance shale oil recovery by reducing the capillary resistance of residual water after hydraulic fracturing and increasing the miscibility between CO2 and oil.

Imidazolium‐based ionic thermoplastic polyurethane with low surface energy and antibacterial activities

AbstractA series of novel thermoplastic polyurethane elastomers with both low surface energy and antibacterial activity were synthesized in this paper. Firstly, four imidazole salt diols with different alkyl chain lengths at the N‐position of imidazolium cation ([CnIm+][Cl−]) were prepared. Then, imidazolium‐based ionic thermoplastic polyurethane elastomers (Si‐ITPUs) were formulated by incorporating polydimethylsiloxane and polytetramethylene glycol as a mixed soft segment, 1,4‐butanediol and [CnIm+][Cl−] as a chain extender, and 4,4′‐dicyclohexylmethane diisocyanate. The structure, thermal stability, mechanical properties, physical crosslinking density, and the anti‐graffiti properties of Si‐ITPUs were evaluated. The surface energy and water absorption were evaluated through static contact angle and water resistance tests, respectively. Furthermore, the antibacterial activities against both Staphylococcus.aureus and Escherichia coli were characterized by the plate colony counting method. The results demonstrated that Si‐ITPUs possessed surface energy of approximately 23 mN/m, which conferred excellent anti‐graffiti and self‐cleaning performance. Furthermore, the increase of the alkyl chain length of substitutions resulted in a decrease in the tensile strength but an increase in the elongation at break. Si‐ITPU‐C4 exhibited optimized antibacterial activities with an antibacterial rate of more than 99.9% against both S. aureus and E. coli. This novel polyurethane is anticipated to find applications in the medical device industry and food processing sector.

Influence of ionic liquid modified gold nanoparticles on conformational transition of poly(N-isopropylacrylamide)-b-poly(acryloylmorpholine) block copolymer

Utilizing stimuli-responsive polymers for surface modification of nanoparticle allows the adjustment of properties for individual system; however, limited research explores the impact of ionic liquid-modified gold nanoparticles (AuNPs) on the conformational phase transition of block copolymers. Herein, we synthesized poly(N-isopropylacrylamide)-b-poly(acryloylmorpholine) (PNIPAM-b-PACMO) copolymers by reversible addition − fragmentation chain-transfer polymerization and investigated the effect of ionic-liquid modified AuNPs (IL-AuNPs) on the aggregation behavior of the copolymer. Copolymerization of PNIPAM with PACMO shifted the lower critical solution temperature (LCST) towards higher temperature in comparison to LCST value of PNIPAM. Addition of IL-AuNPs further raises the transition temperature in concentration dependent manner. A more significant alteration in the transition temperature was observed in the presence of IL-AuNPs with a higher alkyl chain length. The variation in transition temperature of the copolymer by different IL-AuNPs yields benefits in the temperature responsive properties which can helpful for various applications.

Experimental and Simulation Studies of Imidazolium Chloride Ionic Liquids with Different Alkyl Chain Lengths for Viscosity Reductions in Heavy Crude Oil: The Effect on Asphaltene Dispersion.

Heavy crude oil poses challenges in terms of extraction and transportation due to its high viscosity. In the pursuit of effective methods to reduce viscosity in heavy crude oil, this study investigates the potential of imidazolium chloride ionic liquids with varying alkyl chain lengths as viscosity reducers. The experimental results demonstrate that the addition of 1-dodecyl-3-methylimidazole chloride ([C12-MIM]Cl) leads to a maximum viscosity reduction of 49.87%. Solubility parameters were calculated based on characterization of the average molecular structure of the asphaltenes. The viscosity reduction effect is enhanced when the solubility parameter of the ionic liquid closely matches that of the asphaltene. The initial asphaltene deposition point of heavy crude oil is increased from 63% to 68% with the addition of 150 mg/L [C12-MIM]Cl. Furthermore, the average particle size of asphaltene deposits decreases from 79.35 μm to 48.54 μm. The viscosity of heavy crude oil is influenced by the aggregation of asphaltenes. The ability of ionic liquids, especially those with longer alkyl chains, to disperse asphaltene molecules and reduce viscosity has been confirmed through molecular dynamics and quantum mechanical simulations.

Conductometric and spectral analyses of dye-surfactant interactions between indigo carmine and N-alkyltrimethylammonium chloride

The electrical conductivity technique was used to investigate the critical micelle concentration (CMC) of cationic surfactants N-alkyltrimethylammonium chloride (CnTAC; n = 12, 14, 16, and 18). Meanwhile, the interaction between CnTAC and indigo carmine (IC, an anionic dye) was studied using spectrophotometry. Employing the Benesi-Hildebrand and Scott equations, the binding constant (Kb) of IC to the cationic micelles was determined. Calculation of the Gibbs free energy (ΔG) revealed the tendency of IC to bind to micelles. The association between IC and CnTAC clearly depends on the CnTAC concentration: a lower surfactant concentration disrupts the IC-CnTAC complex and decreases IC adsorption, while a higher surfactant concentration has the opposite effect. The alkyl chain length of CnTAC was also found to affect the CMC, Kb, and thermodynamic parameters. A longer alkyl chain reduces the CMC and ΔG and increases Kb, leading to increased solubilization and high spontaneity of the dye. The binding of IC to micelles is ranked as C12TAC < C14TAC < C16TAC < C18TAC.

Alkyl chain engineering of boron dipyrromethenes for efficient photodynamic antibacterial treatment

Photodynamic therapy has been widely employed as an alternative strategy against bacterial infection. Molecular structure has a profound effect on the antibacterial ability of photosensitizers (PSs). Herein, we designed and synthesized a series of boron dipyrromethene (BODIPY)-based photosensitizers with different alkyl chain lengths, and then their antibacterial activities were compared. Among these BODIPYs, the BODIPY with octyl (BDP-8) exhibits the best antibacterial effect, while the antibacterial performance of BODIPY with dodecyl (BDP-12) is the worst. This work provides instructive information for further development of effective photodynamic antimicrobial agents.

Simulating the behavior of antioxidant to explore the mechanisms of oxidative stability in Pickering emulsion

This study explores effective strategies for bolstering emulsion oxidative stability via optimized interfacial distribution of varying hydrophobicity antioxidants (gallic acid, propyl gallate, octyl gallate) in zein nanoparticle (ZP) stabilized Pickering emulsions. Experimental and simulation methods revealed that antioxidant (AO) with higher hydrophobicity or loaded into ZP demonstrated stronger hydrogen bonding and van der Waals interactions with ZP. This increased interfacial loading of antioxidants resulted in improved oxidative stability in Pickering emulsions. The flow, distribution and orientation of AO, as revealed by dissipative dynamics simulations, highlighted the role of hydrophobic interactions during initial AO migration, influenced by varied alkyl chain lengths. Subsequent interface rearrangements arose from conservative force interactions between the AO's phenol hydroxyl ends and ZP. These findings inform effective interfacial engineering to optimize antioxidant efficiency, guiding practical applications in emulsion systems for improved oxidative stability.

Deep Eutectic Solvents with Different Alkyl Chain Lengths as Inhibitors for Shale in Water-Based Drilling Fluids

Deep Eutectic Solvents with Different Alkyl Chain Lengths as Inhibitors for Shale in Water-Based Drilling Fluids

Scrutinizing the antibacterial activity of poly (1‐vinyl‐3‐alkyl imidazolium) ionic liquids: experimental and computational approach

AbstractBackgroundAntimicrobial resistance has become a serious concern and threat to global health. This has triggered the need for the design of new antimicrobials. In this study, poly‐ionic liquid (PIL) homopolymers have been designed by varying the alkyl chain lengths to evaluate their pathogeneses against Gram‐positive (Staphylococcus aureus) and Gram‐negative bacteria (Escherichia coli).ResultsThe results demonstrated that the antimicrobial and antibiofilm activities depend on the alkyl chain length of PILs (C10 &gt; C8 &gt; C6). To support the experimental findings, in silico analyses were performed to explore the structural and functional information of bacterial RNA polymerase (RNAP) enzymes. A switch region was identified between RNAP β subunit (RpoB) and RNAP β' subunit (RpoC) with 1119 amino acids (aa) and 1504 (2–1505) aa, respectively. The docking analysis reflected the docking energies −5.313 kcal mol−1 for RNAP‐poly‐1‐vinyl‐3‐hexyl imidazolium complex, −4.634 kcal mol−1 for RNAP‐poly‐1‐vinyl‐3‐octyl imidazolium complex, and −3.456 kcal mol−1 for RNAP‐poly‐1‐vinyl‐3‐decyl imidazolium complex.ConclusionThe synthesized PIL samples exhibited antibacterial and antibiofilm activities against E. coli and S. aureus. However, the effect on E. coli was more prominent in comparison to S. aureus. The results indicated that both electrostatic interaction and hydrophobic effect played a vital role in enhancing the antibacterial as well as antibiofilm activities. In addition, in silico analysis identified the ‘switch region’ between RNAP β subunit (RpoB) and RNAP β subunit (RpoC). The novel target appeared to be a binding region for PILs and restricted the synthesis of bacterial RNA. It can be concluded that imidazolium‐based PILs can be used as safe antibacterial materials in the healthcare sector. © 2024 Society of Chemical Industry (SCI).

Design, synthesis and antibacterial evaluation of low toxicity amphiphilic-cephalosporin derivatives

Global public health is facing a serious problem as a result of the rise in antibiotic resistance and the decline in the discovery of new antibiotics. In this study, two series of amphiphilic-cephalosporins were designed and synthesized, several of which showed good antibacterial activity against both Gram-positive and Gram-negative bacteria. Structure-activity relationships indicated that the length of the hydrophobic alkyl chain significantly affects the antibacterial activity against Gram-negative bacteria. The best compound 2d showed high activity against drug-susceptible Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA) with MICs of 0.5 and 2–4 μg/mL, respectively. Furthermore, 2d remained active in complex mammalian body fluids and had a longer post-antibiotic effect (PAE) than vancomycin. Mechanism studies indicated that compound 2d lacks membrane-damaging properties and can target penicillin-binding proteins to disrupt bacterial cell wall structure, inhibit the metabolic activity and induce the accumulation of reactive oxygen species (ROS) in bacteria. Compound 2d showed minimal drug resistance and was nontoxic to HUVEC and HBZY-1 cells with CC50 > 128 μg/mL. These findings suggest that 2d is a promising drug candidate for treating bacterial infections.

Mesomorphism of imidazolium-based fluorinated ionic liquids

Ionic liquid crystals have received increasing interest due to their positional and/or orientational order as well as the freedom in molecular motions that arise from the formation of mesophases between solid and liquid. While phase changes of non-fluorinated ionic liquids have been widely reported, there have been few reports on the temperature-dependent phase behavior of fluorinated ionic liquids. Here, we present a series of fluorinated ionic liquids with methylimidazolium cations bearing 1H, 1H, 2H, 2H-perfluoroalkyl chains (butyl, hexyl, and octyl) and halide counterions, and demonstrate their thermotropic mesomorphism. These cations were synthesized under solvent-free conditions, and anion exchange was used to vary the halide counterion. The thermal behavior of the compounds was studied using thermogravimetric analysis and differential scanning calorimetry, revealing both liquid crystalline phases and solid-solid phase transitions. We discovered that the mesomorphic properties of the ionic liquids depend strongly on the length of the perfluoroalkyl pendants. Specifically, ionic liquids with a fluorinated butyl chain showed no mesophase behavior while those with hexyl and octyl fluorinated chains displayed liquid crystalline phases at temperatures above 100 °C. The mesophases were further characterized by polarized optical microscopy and powder X-ray diffraction, highlighting the impact of the fluorinated alkyl chain length.

Design of new zwitterionic microparticles with intrinsic antibacterial activity

AbstractThe crosslinked porous microparticles based on glycidyl methacrylate, N‐vinylimidazole, and triethylene glycol dimethacrylate (molar ratio between monomers 40:30:30) obtained in the presence of three porogenic agents (toluene, n‐butyl acetate, and toluene:n‐butyl acetate mixture, 1:1, v/v) are used as precursors in the polymer analogous reactions with some betainizing agents (sodium monochloroacetate, acrylic acid, methacrylic acid and 1,3–propane sultone) in order to introduce the carboxybetaine/sulfobetaine groups to the tertiary nitrogen atom from the imidazole ring. ATR–FTIR spectroscopy is used to highlight the presence of carboxybetaine/sulfobetaine groups on the structure of the microparticles, but also to calculate the degree of betainization (55.91%–90.2%) The zwitterionic microparticles are characterized by scanning electron and atomic force microscopies, equilibrium swelling ratio as a function of pH values, swelling kinetics, ion exchange capacities and particle size distribution. Also, the parameters of porous structure (pore diameter, pore volume, porosity, and specific surface area) are determined by mercury porosimetry. The antibacterial properties of Gram‐positive (Enterococcus faecalis and Staphylococcus aureus) and Gram‐negative (Escherichia coli and Klebsiella pneumoniae) bacteria are evaluated. It is found that the zwitterionic structures containing a shorter length alkyl chain between ionic groups exhibit excellent antibacterial activity of about 80%–92%.

Synthesis and antibacterial properties of alkyl substituted sulfonium salt

The development of new antibacterial agents is particularly important in the battle against pathogenic microorganisms. In this study, sulfonium ions were used as the structural core to synthesize alkyl-substituted ionic compounds as antibacterial agents. The antimicrobial activity of sulfonium ionic compounds against Escherichia coli and Staphylococcus aureus was analyzed by measurement of the minimum inhibitory concentration and minimum bactericidal concentration. The effects of sulfonium salts on cell membrane integrity and permeability were investigated by detecting the extracellular proteins leakage of E. coli and S. aureus upon contact treatment, and observing the bacteria’s ultrastructural changes with transmission electron microscopy. The results showed that all the sulfonium salts exhibited resistant activity. Sulfonium salt with alkyl chain length of 16 carbon presented the strongest resistance with MIC of 30 and 3.75 μmol/L, and MBC of 120 and 60 μmol/L against E. coli and S. aureus, respectively. After treatment with sulfonium salts, the permeability of the membrane of E. coli and S. aureus cells changed, and the exudation of extracellular proteins increased significantly. The transmission electron microscope showed that the surface of the bacteria had shrunk and the cell walls had burst. The group of sulfonium salt compounds can destroy the integrity of cell membrane and change membrane permeability to achieve antibacterial purposes.

Phenothiazine Derivatives as Small-Molecule Organic Cathodes with Adjustable Dropout Voltage and Cycle Performance.

Compared with conventional inorganic materials, organic electrodes are competitive candidates for secondary battery cathodes due to their resourcefulness, environmental friendliness, and cost-effectiveness. Much effort is devoted at the level of chemical structure, while ignoring the impact of molecular aggregation on battery behavior. Herein, this work designs a series of organic molecules with two electrochemically active phenothiazine groups linked by different lengths of alkyl chain to regulate molecular symmetry and crystallinity. The results emphasize the equally important role of molecular aggregation and chemical structure for battery performance. Among them, 2PTZ-C7H14|Li cell exhibits the most impressive cycle and rate performance. At the high rate of 50 C, it can still deliver a capacity of 63.4 mA h g-1 and 74.5% capacity retention after 10000 cycles. Besides, the dropout voltage of 2PTZ-C9H18|Li cell is only 52 mV, which is among the lowest reported for lithium-organic batteries to the best of the author's knowledge.

Dissolution dynamics of poly(4-hydroxystyrene-co-methacrylic acid) in tetraalkylammonium hydroxide aqueous solutions

Resist materials and their lithography processes are essential for achieving further miniaturization in semiconductor microfabrication. In the sub-20 nm half-pitch region, the development process becomes particularly important due to the occurrence of stochastic defects (pinching and bridging). However, the details of dissolution dynamics are still unclear. In this study, we investigated the dissolution dynamics of poly(4-hydroxystyrene-co-methacrylic acid) (PHSMA) films in tetraalkylammonium hydroxide (TAAH) aqueous solutions using a quartz crystal microbalance method. PHSMA is a typical backbone polymer used in extreme UV lithography. For poly(4-hydroxystyrene) films, it has been reported that the dissolution mode changed when the alkyl chain length of TAAH increased. However, the mode change was not observed for PHSMA films. This difference is considered to be caused by the formation of thick transient swelling layers of PHSMA films owing to the fast water intake and the molecular interaction of the hydroxyl groups of hydroxystyrene units.

Simulation of adsorption behavior for various functionalized graphene nanosheets containing alkyl chain/polymer nanocomposites using ReaxFF

The non-covalent interactions in polymer/functionalized graphene nanosheet (FGN) nanocomposites containing the alkyl chain were investigated in this study. For this purpose, the non-covalent interactions at the interfaces of the mentioned polymer nanocomposites were accurately assessed using reactive molecular dynamics (RMD) simulation. The considered structures included poly(3-(4-n-octyl)-phenylthiophene) (POPT) and poly(3-phenylhydrazone thiophene) (PPHT) with FGNs featuring primary amine (PA), secondary amine (SA), alkanolamine (AA), and diamine (D) functional groups in alkyl chain. The functional groups varied in alkyl chain lengths via n (n equal to carbon atoms). Results from RMD simulations highlighted that the minimum interaction energy occurred between polymers and G-SA 1 %. PPHT exhibited strong interactions with G-D-4 1 % and G-PA-16 1 %. Contrary to other FGN, especially G-PA 1 %, increasing alkyl chain length in G-SA 1 % negatively affected polymers/G-SA 1 % interaction energy. Moreover, Hydrogen bonding (H-bonding) was examined in all different nanocomposites of PPHT/FGN. Also, the effect of an increase in coverage percentage and temperature was evaluated. These findings offer valuable insights into interactions of polymer-FGN with different alkyl chain lengths, aiding in the design of tailored nanocomposites.

3He@C60 as a Concise Probe in Complex Systems: Diels‐Alder Reac‐tions of Fullerene with Different Bis Anthracene Compounds

AbstractThree bis‐anthracene (BA) compounds, characterized by varying alkyl chain lengths between the two anthracene groups, were synthesized and investigated using 3He NMR spectroscopy on He@C60 derivatives. The Diels‐Alder reaction of these BAs with fullerene was comprehensively explored. Findings disclosed that BAs with shorter linkers formed mono‐adducts with 3He@C60 at lower concentrations. Conversely, the BA compound with the longest linker (1 c) yielded both mono‐adducts and bis‐para‐adducts with C60, marked by a distinct 3He NMR signal peak for bis‐adducts at −12.84 ppm. Importantly, the versatility of the 3He@C60 probe was exemplified in characterizing intricate fullerene reactions that conventionally pose challenges. Theoretical analyses validated reaction products, with computational models substantiating experimental results.

Extractive separation of citral and limonene with quaternary Ammonium/Alkanediol deep eutectic Solvents: An experimental and mechanistic study

As an aldehyde derivative of monoterpene, citral is the main oxyterpene in various botanical essential oils which has been widely applied in food, cosmetics and medicines. The separation of oxyterpenes from terpenes (deterpenation) improves its stability and quality, which is an essential step for production of citral with high market value. Herein, the extractive separation of citral and limonene using deep eutectic solvents (DESs) of quaternary ammonium/alkanediol was explored. Influence of DESs components, including different quaternary ammonium salts as hydrogen bond acceptors (HBAs), various alkanediols as hydrogen bond donors (HBDs) and the changing of HBA to HBD ratios on citral extraction were studied. Distribution coefficient, selectivity and extraction yield of the citral of these DESs were experimentally evaluated. Among the HBAs investigated, tetrabutylammonium bromide (TBABr) was determined to be the suitable one, since halide Br- was better than Cl-, and quaternary ammonium cations with longer alkyl chain length was preferable. Meanwhile, 1,2-propanediol (1,2-PDO) outperformed other alkanediols, and higher HBD contents in DESs facilitated the separation. TBABr/1,2-PDO (molar ratio 1:10) exhibited the best performance, with citral distribution coefficient 1.28, selectivity 13.65 and extraction yield 64.26%. The type and strength of molecular interactions between citral solute and DESs were identified by employing quantum chemistry calculation and molecular dynamic simulations. The performance difference of these DESs can be ascribed to the difference of the direct hydrogen bond between the α-OH of alkanediols and the O from citral carbonyl group during extraction. The mechanisms exploration provides insights for rational fine-tuning the novel DESs with better deterpenation performance.

Exploring binding affinity of 1-n-Alkyl-3-methylimidazolium chloride with iron porphyrin and electron uptake ability of the ionic liquid-FeP complex

Interaction of ionic liquids with iron porphyrin (FeP) arises in a number of application of ionic liquids such as dye-sensitized solar cells, batteries, and conversion of CO2 to value-added products, etc. Furthermore, ionic liquid-FeP interactions are thought to be responsible for ionic liquid biodegradation and catalytic breakdown of ionic liquids. Despite the importance of ionic liquid-FeP interactions, there is a lack of information on what conformations ionic liquids adopt when presented to FeP and how thermodynamics of subsequent electron transfer reaction is affected. To begin to answer these questions, electronic structure calculations are performed to assess how the binding propensity of the homologous series of 1-n-alkyl-3-methylimidazolium [Cnmim]Cl (n = 2, 4, 6, 8, 10) to FeP is affected as the alkyl chain length and the initial conformation of the cation presented to FeP are varied. The conceptual density functional theory framework is then invoked to compute the electrophilicity index of the ionic liquid-FeP complex to glean insight into the ability of the complex to acquire an electron. Calculations suggest two equally likely conformations of ionic liquids with similar Gibbs free energy change; however, the enthalpic and entropic contributions differ based on the conformation adopted by ionic liquids which in turn affects the propensity of the subsequent electron transfer process. The importance of results is discussed in terms of experimentally observed alkyl chain length-dependent biodegradability of ionic liquids.

Micellar structure of nonenyl succinic anhydride modified pullulan in aqueous solution

A polydisperse pullulan (PUL) sample was hydrophobically modified by nonenyl succinic anhydride (NSA) with four different degree of substitution (DS) samples (PUL-NSA). Small-angle X-ray scattering functions and pyrene-probe fluorescence were measured for PUL-NSA samples in 0.05 M aqueous NaCl. Both the SAXS and fluorescence results can be explained by the loose flower necklace model well. The SAXS results of PUL-NSA was different from that of the random copolymer of octenyl succinic anhydride hydrophobically modified PUL (PUL-OSA) with approximate DS. The stiffness of the flower necklace qFN for PUL-NSA was lower than PUL-OSA, probably due to the differences in the alkyl chain length.