Acid Chloride Research Articles

Positively charged nanofiltration membranes with gradient structures for enhancing separation properties

Creating a gradient structure in a separation layer is an effective approach for enhancing separation performance of thin film composite membranes. Here we present the preparation of a positively charged nanofiltration membrane with a gradient structure. An inner layer consisting of a loose polyester separation layer with large pores was formed through the interfacial polymerization (IP) reaction between triethanolamine (TEA) and trimesoyl chloride (TMC). And a dense and thin top layer composed of a polyamide separation layer was obtained by secondary interfacial polymerization (SIP) reaction using polyethyleneimine (PEI) along with unreacted TMC and residual acyl chloride groups of IP reaction. The influences of TEA concentration, PEI concentration and SIP time on the physicochemical properties and separation performances of the membrane were systematically analyzed. Our results show that the presence of the gradient structure optimized mass transfer pathways and reduced mass transfer resistance, resulting in significantly improved permeability of 13.0 ± 0.5 L·m−2·h−1·bar−1 (over 3 times compared with control-PEI), high MgCl2 rejection of 91.7 ± 0.6 %, and an excellent stability and anti-fouling performance. Our work provides valuable insights and guidance for developing high-performance positively charged NF membrane with gradient structures.

Dual functionalization of polyamide reverse osmosis thin film composite membrane for improving chlorine resistance

Contemporary high-efficiency polyamide (PA) membranes are constructed using aliphatic or aromatic amines combined with acyl chlorides. Nevertheless, the aromatic rings attached to the N–H group within the amide linkages are vulnerable to degradation by chlorine. The surface of a PA reverse osmosis (RO) membrane was altered in this work through the dual functionalization of tannic acid (TA) and silver nanoparticles (Ag NPs) to improve separation performance, chlorine resistance, and anti-bacterial capabilities of membranes. This study provides an insight in the role and synergistic effects of TA and Ag NPs for enhancing the chlorine resistance of the modified TFC membranes. The outcome indicated that the RO-TA/Ag modified membrane exhibited the maximum rejection of 98.31%, slightly surpassing the pristine RO membrane, which had a rejection rate of 96.52%. The RO-TA/Ag modified membrane also shown improved chlorine tolerance against 500 ppm sodium hypochlorite solution (NaClO), as evidenced by X-ray photoelectron spectroscopy (XPS) measurement which revealed reduced chlorine content in contrast to pristine RO and RO-TA membrane. The RO-TA/Ag membrane exhibited the largest inhibitory zone for both Gram-positive, S. aureus and Gram-negative, E. coli bacteria. The synergistic effects of the dual functionalization of TA and Ag NPs which render the modified membrane with high anti-chlorine and anti-bacterial capabilities are discussed.

Visible-Light-Promoted Radical Cascade Cyclization of 2-Vinyl Benzimidazoles: Access to Benzo[4,5]imidazo[1,2-b]isoquinolin- 11(6H)-ones.

A visible-light-enabled photoredox radical cascade cyclization of 2-vinyl benzimidazole derivatives is developed. This chemistry is applicable to a wide range of N-aroyl 2-vinyl benzimidazoles as acceptors, and halo compounds, including alkyl halides, acyl chlorides and sulfonyl chlorides, as radical precursors. The Langlois reagent also serves as an effective partner in this photocatalytic oxidative cascade process. This protocol provides a robust alternative for rendering highly functionalized benzo[4,5]imidazo[1,2-b]isoquinolin-11(6H)-ones.

Reactive extraction for the separation of glyceric acid from aqueous solutions with 2-naphthaleneboronic acid and tri-octyl methyl ammonium chloride

Reactive extraction for the separation of glyceric acid from aqueous solutions with 2-naphthaleneboronic acid and tri-octyl methyl ammonium chloride

Synthesis of N‐Acyl Indole‐3‐Carboxaldehyde Derivatives and Polyvinyl Alcohol Acetalization with 1‐Propionylindole‐3‐Carboxaldehyde

AbstractA series of seven stable amide derivatives based on indole‐3‐carboxaldehyde were synthesized with high yields using various aliphatic and aromatic acyl chlorides, triethylamine and DMAP as the catalyst at room temperature. Structural characterization was performed using FT‐IR, 1 H‐NMR, 13C‐NMR and LC–MS techniques. To develop bioactive material, acetalization of water‐soluble polyvinyl alcohol was achieved by reacting one of the N‐acyl derivatives, 1‐propionylindole‐3‐carboxaldehyde, in the presence of a p‐TSA catalyst to form polyvinyl acetal with pendant bioactive groups. The polymer was analyzed using 1 H‐NMR, FT‐IR, TGA, DSC, FE‐SEM and EDX spectroscopic techniques. The polymer was water‐insoluble with enhanced thermal stability compared to pure polyvinyl alcohol. This approach for developing N‐acyl derivatives of indole‐3‐carboxaldehyde and then reacting one of the monomers with polyvinyl alcohol to improve its thermal properties and stability in humid conditions has proven successful.

Seed priming with mepiquat chloride and foliar applications of salicylic acid and proline improve the adverse effects of water deficit in cotton (Gossypium hirsutum L.)

Seed priming with mepiquat chloride and foliar applications of salicylic acid and proline improve the adverse effects of water deficit in cotton (Gossypium hirsutum L.)

Investigation of Iron Dissolution Mechanism in Acidic Solutions with and without Dissolved CO2—Part I: Electrochemical Impedance Spectroscopy Measurements

Aqueous CO2 corrosion of mild steel is one of the major problems in the oil and gas industry. While current understanding primarily focuses on cathodic reaction mechanisms, less attention has been given to the impact of aqueous CO2 on the anodic iron dissolution reaction. In contrast, the mechanism of iron dissolution in strongly acidic environments has been thoroughly investigated. Among the reaction mechanisms found in the open literature, a multipath mechanism was identified that could explain the iron dissolution in strong acidic sulfate solution; both in terms of steady-state polarization sweeps and impedance data at various pH values and current densities. However, the role of aqueous CO2 in solutions containing chlorides on the mechanism of iron dissolution remained an open question. The present study used electrochemical impedance spectroscopy (EIS) as the main technique, to study the mechanism of iron dissolution in strong acid chloride solution with and without the presence of CO2. Results showed that the presence of chloride ions (0.5 M) decreased the rate of iron dissolution by competing with hydroxide ions to adsorb on the metal surface, forming chloride-containing intermediate species that participate in the iron dissolution reaction. The resulting decrease in the availability of hydroxide intermediates, which are more effective at enhancing the reaction rate compared to chloride-containing intermediates, leads to an overall decrease in the rate of iron dissolution. While the presence of CO2 increases anodic current density, EIS investigation revealed that neither aqueous CO2 nor other carbonic species directly react on the bare metal surface to form adsorbed intermediates involved in the anodic reaction. EIS investigation suggested that aqueous CO2 may induce changes in the chemical composition of adsorbed species, rate constants, and surface coverage, thereby altering the kinetics of the underlying reactions.

Preparation, physicochemical analyses, and comparative evaluation studies of deep eutectic solvents (DES) from non-conventional precursor materials applied as catalytic curing agents for epoxy resin

Curing agents for epoxy resins play a significant role in initiating crosslinking reactions resulting in the hardened and durable material with enhanced properties as per end-user applications. The industrial world still lacks efficient, environmentally friendly, and cheap curing agents for epoxy resins. Here, we report the development of deep eutectic solvents (DESs) based on N, N’-Bis(2-aminoethyl)ethane-1,2-diamine (commonly known as triethylenetetramine, TETA) as hydrogen bond donor (HBD), and salicylic acid (SA) and choline chloride (CC) as hydrogen bond acceptor (HBA). The formulated DESs are suggested to be relatively safe, affordable, and eco-friendly and the active groups in the DESs are capable of initiating crosslinking reactions. The physical stability of the formulated deep eutectic solvents was examined by polarizing optical microscopic (POM) analysis, which confirmed the absence of any crystals or residues. The purity was ensured by 13C nmr spectroscopy. Additionally, supportive evidence for the hydrogen bond formation between the constituents was gained from the outcomes of FTIR, 1H nmr, and mass spectrometry. Deep depression in melting points was confirmed from DSC studies, and TGA suggested better thermal stability for DESs than its constituents. Density functional theory (DFT) at B3LYP6-31G* of Gaussian computational framework was applied to energetically optimize the isolated structure and determine the bond lengths in angstroms. The structural characteristics and nonbonding interactions of DESs were investigated by the same. In addition, the density and rheological characteristics were assessed for the ideal utilization of the formulated DESs as epoxy resin curing agents. The detailed comparative studies demonstrated the advantages of deep eutectic solvents over conventional curing agents. The efficacy of the formulations as a curing agent was primarily confirmed from FTIR analysis and the curing behavior was investigated by DSC studies.

Combined effect of polyelectrolyte assisted interfacial polymerization and tannic acid protective surface modification to boost organic solvent nanofiltration performance

Organic solvent nanofiltration (OSN) is an effective technology for separating solute with molecular weight of 200–1000 Da (Da) from organic solvents. However, as the core of this technology, most of OSN membranes exhibit a low solvent permeance. Herein, a highly permeable OSN membrane was prepared via a poly (sodium 4-styrenesulfonate) (PSSNa)-assisted interfacial polymerization reaction using ultra-low content of aqueous monomer solution, followed by a protective modification using tannic acid (TA) grafting onto the nascent polyamide surface, and a post chemical crosslinking treatment as well as an activation treatment. PSSNa manipulates the diffusion and distribution of the m-Phenylenediamine monomers, leading to a looser and thinner polyamide layer. TA molecules successfully reacted with the remaining acyl chloride groups on the nascent polyamide layer surface and formed ester, thus preventing the surface from subsequent crosslinking reaction and also making the selective layer looser, which is beneficial for solvent permeation. Moreover, the TA modification makes the surface more hydrophilic, thus further helps to improve the solvent permeance of OSN membrane. The optimal membrane possesses an excellent ethanol permeance of 71.5 L m−2 h−1 MPa−1, an increment of 41.6 % as compared with the baseline OSN membrane, while keeping a rejection of 98.2 % for rhodamine B (RDB). Meanwhile, the surface of optimal membrane is ultra-smooth, with an average roughness of 4.4 nm, which is much beneficial for antifouling. Moreover, the OSN membrane possesses a brilliant durability performance, with only a 1.5 % decrease of the RDB rejection after being immersed in N, N-Dimethylformamide (DMF) at room temperature for 115 d, and only a further 0.3 % decrease of the RDB rejection after being further immersed in DMF at 80 °C for another 11 d, indicating its superior solvent resistance, which makes it a promising candidate for treating organic solutions from pharmaceutical and textile industries.

Synergistic effect of seaweed extract and boric acid and/or calcium chloride on productivity and physico-chemical properties of Valencia orange.

Many citrus species and cultivars are grown successfully in tropical and subtropical countries, as well as in arid and semi-arid regions with low levels of organic matter and low cation exchange, resulting in lower nutrient uptake by the plant. The essential nutrients needed for citrus flowering and fruit set are limited in winter due to a reduction in transpiration rate, negatively effecting vegetative growth, flowering, yield, and fruit quality. The present investigation was carried out to assess the nutritional status, fruit yield parameters, and fruit quality of Valencia orange trees after foliar spraying of seaweed extract (SW) combined with calcium chloride and boric acid and their combinations in the 2020/2021 and 2021/2022 seasons. The treatments were arranged in a split-plot design (three levels spraying seaweed extract × four levels spraying calcium chloride and boric acid and their combinations × four replicates × one tree/replicate). The results indicated that all of the characteristics measured, including leaf chlorophyll, leaf mineral contents, fruit yield parameters, fruit physical properties, and fruit chemical properties, were significantly affected by the foliar spraying of seaweed extract (SW) combined with calcium chloride and boric acid and their combinations. Although all treatments increased the productivity and the physical and chemical properties of Valencia orange fruits compared to the control, a treatment of 10 g/L SW combined with 0.5 g/L boric acid and 1 g/L calcium chloride produced superior results. This ratio of SW, boric acid, and calcium chloride is therefore recommended to enhance productivity and improve the physico-chemical properties of Valencia orange for greater fruit yield.

Inhibition of silica scaling with functional polymers: Role of ionic strength, divalent ions, and temperature

High concentrations of dissolved silica in saline industrial wastewaters and brines cause silica scale formation, significantly hampering the efficacy of diverse engineered systems. Applying functional polymers as scale inhibitors in process feedwater is a common strategy to mitigate silica scaling. However, feedwater characteristics often vary widely, depending on the specific processes, making the inhibition of silica scaling challenging and complex. In this study, we systematically investigate the role of ionic composition, specifically ionic strength and divalent ions, and solution temperature, in inhibiting silica scaling using molecularly designed amine/amide polymers. The inhibitor demonstrates effective stabilization of silicic acid, with inhibition efficiency of 74 and 55 % in the absence and presence of 20,000 ppm NaCl, respectively. However, further increasing the ionic strength of oversaturated silicic acid solutions significantly diminishes inhibition performance, rendering it ineffective at 180,000 ppm NaCl. Divalent inorganic cations exhibit a stronger impact on reducing inhibition efficiency compared to sodium ions. Molecular dynamics simulations reveal a competition mechanism between anionic silicic acid reactants (i.e., H3SiO4−) and chlorides for binding to ammonium groups within the polymeric inhibitor. Additionally, cations form clusters with H3SiO4− ions, hindering their stabilization with polymeric inhibitor. Notably, at elevated temperatures, the inhibitor achieves near-perfect inhibition for 500 ppm silicic acid solutions. This comprehensive assessment provides important insights into the effectiveness of silica scaling inhibitors under solution conditions relevant to real-world applications, addressing the challenges posed by varying solution parameters in diverse industrial processes.

Bio-based phytic acid/amino acid complex coating for antimicrobial and flame-retardant cotton fabrics

Here, a novel multifunctional coating containing bio-based phytic acid (PA), L-glutamic acid (L-Glu), and trimesoyl chloride (TMC) is constructed by a simple soaking strategy, giving cotton fabrics excellent flame retardancy, washability, and antibacterial properties. The coating layer on the cotton surface was prepared via the electrostatic and hydrogen bonding between PA and L-Glu, accompanied by the interface polymerization between PA, L-Glu, and TMC. Among them, the limiting oxygen index value of the treated cotton fabrics (C2 and C2-TMC) was as high as 40 %. During the vertical flammability test, both C2 and C2-TMC cotton showed self-extinguished behavior with a short damaged length (≤50 mm). Remarkably, the LOI of C2-TMC sustained a high value (30 %) even after 300 laundering cycles, maintaining its self-extinguishing behavior in the vertical combustion test. Additionally, in the cone calorimetry test, peak heat release rate and total heat release of treated cotton were lower than control cotton. Surprisingly, after 30 or 60 laundering cycles, the C2-TMC cotton exhibited excellent antibacterial activity against Escherichia coli, Staphylococcus aureus, and Candida albicans due to the continuous exposure of PA and L-Glu. Moreover, the coating layer on the cotton surface had little impact on the mechanical properties and feel of the fabric.

Highly Active Cu@NC Catalyst Derived from Porous Organic Polymer for Solvent‐Free Coupling of Acyl Chlorides with Alkynes

AbstractCopper promoted Sonogashira coupling has recently emerged as an attractive route for synthesizing α, β‐Acetylenic ketones (ynones). In this study, a porous organic polymer based on [2,6‐Bis(1,2,3‐triazol‐4‐yl)pyridine] (BTP) was prepared through oxidative coupling. By incorporating copper salt and subsequent pyrolysis, copper encapsulated N‐doped carbon materials were obtained. The resulting copper/carbon materials exhibited excellent catalytic performance for the coupling of acyl chlorides and alkynes due to their large surface area, abundant mesopores, and uniformly distributed metal nanoparticles. The reaction proceeded efficiently, yielding ynones with good to excellent yields at room temperature within a short reaction time (4 h) using only 0.4 mol % catalyst. Compared to previously reported copper nanocatalysts, the N‐doped carbon materials supported copper catalyst demonstrated higher catalytic activity and operated at lower reaction temperatures. Additionally, the catalyst displayed reliable recyclability without any significant loss in catalytic activity.

Salicylic Acid and Calcium Chloride Seed Priming: A Prominent Frontier in Inducing Mineral Nutrition Balance and Antioxidant System Capacity to Enhance the Tolerance of Barley Plants to Salinity.

The current investigation aims to underline the impact of salicylic acid or calcium chloride seed pre-treatments on mineral status and oxidative stress markers, namely levels of electrolyte leakage (EL) and lipid peroxidation levels, measured as thiobarbituric reactive substances (TBARS), and the activity of some antioxidant enzymes in roots and leaves of plants in two barley species grown under various salt treatments. Overall, our results revealed that salinity inhibits essential nutrient absorption such as iron, calcium, magnesium and potassium and stimulates the absorption of sodium. Also, this environmental constraint induced oxidative stress in plants in comparison with the control conditions. This state of oxidative stress is reflected by an increase in TBARS content as well as the stimulation of EL values. In addition, salinity induced disturbances in the activity of antioxidant enzymes, which were mainly dependent on the applied salt concentration and the species. In addition, Hordeum marinum maintained high antioxidant enzyme activity and low levels of oxidative stress parameters, which reinforces its salt-tolerant character. Importantly, salicylic acid or calcium chloride seed priming alleviated the mineral imbalance and the oxidative damage induced by salinity. Moreover, seed priming improves iron, calcium magnesium and potassium content and limitsthe accumulation of sodium. Also, both treatments not only decrease TBARS levels and limit EL, but they also stimulate the antioxidant enzyme activities in the leaves and roots of the stressed plants as compared with stressed plants grown from non-primed seeds. Interestingly, the beneficial effects of the mentioned treatments were more notable on Hordeum vulgare species.

Hemisynthesis of Pentacyclic Triterpenoids from Diospyros foxworthyi with In vitro and In silico Anti-malarial Evaluation

Abstract: A total of twelve pentacyclic triterpenoid derivatives based on betulin (1) and lupeol (2) scaffolds isolated from Diospyros foxworthyi were hemisynthesized by acylation or acetylation reactions with appropriate acid chloride or acetic anhydride. The structures of the hemisynthesised compounds were characterised by means of FT-IR, 1D- and 2D-NMR, as well as HRMS analysis. These compounds were assayed for in vitro anti-malarial studies by inhibition of β-hematin formation assay with chloroquine as a positive control. Compounds 1d and 2f showed the strongest potential as β-hematin formation inhibitors with IC50 values of 6.66 ± 1.36 and 11.89 ± 0.15 μM, respectively, compared with the positive control (chloroquine; IC50 = 37.50 ± 0.60 μM). In silico molecular docking simulations were performed using AutoDock Vina for compounds 1d and 2f to investigate the binding interactions and free energy of binding (FEB) with the hemozoin supercell crystal structure (CCDC number: XETXUP01). The findings revealed several hydrophobic interaction modes between the 1d, 2f and hemozoin, with calculated FEBs of -8.4 ± 0.2 and -8.9 ± 0.0 kcal mol-1, indicating strong and favourable interactions.

Features of the Conformational Dynamics of Cyclopropanoic Acid Fluoride and Cyclopropanoic Acid Chloride Molecules in the Ground Electronic State

Features of the Conformational Dynamics of Cyclopropanoic Acid Fluoride and Cyclopropanoic Acid Chloride Molecules in the Ground Electronic State

Simple and effective synthesis of functionalized (hydroxymethylene)bis(phosphonic) acids

‘Technical’ tris(trimethylsilyl) phosphite, (Me3SiO)3P, as a mixture with (Me3SiO)2P(O)H and (Me3SiO)3P(O) (71 : 20 : 9) was obtained upon the action of (Me Si) NH on phosphorous acid H3PO3 in the presence of catalytic amount of Me3SiCl. The action of this material on acid chlorides RC(O)Cl affords (hydroxymethylene)bis(phosphonic) acids RC(OH)[P(O)(OH)2]2 in preparative yields.

Corrosion of Ni-based alloy coatings prepared by laser cladding in high-temperature chloride environment

Due to the complex incineration environment of waste incineration power generation boilers generates large amounts of acidic gases (such as Cl2 and HCl) and alkali metal chlorides (such as NaCl and KCl), leading to boiler corrosion failure. Herein, a new type of NiCrAlTi alloy coatings was deposited on 304 stainless steel surfaces by laser cladding technology. High-temperature corrosion experiments were then carried out at 650 °C for 64 h and the results were compared with those of traditional Inconel625 alloy coating. The high-temperature chloride corrosion mechanism and the corrosion resistance of alloy coatings were examined. The results revealed the decomposition of chlorides, such as HCl, NaCl, and KCl into Cl2 at high temperatures as the source of corrosion of high-temperature chlorides. The released C12 reacted with the metals present in the coating to form nonprotective metal chlorides. The low melting point and high vapor pressure of metal chlorides allowed their transition into a gaseous state to diffuse outward and oxidize into Cl2. In turn, the released Cl2 reacted with the metal to induce corrosion. During the corrosion process of NiCrAlTi alloy coating, a Cr depletion zone was induced, and a continuous Al2O3/TiO2/Cr2O3 three-layer protective film was formed on the coating surface, conducive to better alleviating the corrosion caused by the reaction between Cl2 passing through the film and the metal substrate. Under the conditions of this experiment, the corrosion resistance of NiCrAlTi alloy coating is 1.8 times that of the common material 304 stainless steel, and about 1.2 times that of Incon625 alloy coating. With the extension of the experiment, its corrosion resistance will be better. Overall, rich experimental data and theoretical guidance were provided for further research and development on high-temperature chloride corrosion-resistant alloys or coating materials for high-efficiency cost-effectiveness boilers.

Recyclable multifunctional ion conductive elastomers for strain/temperature sensors and bioelectrodes

Ionic conductive elastomers based on polymerizable deep eutectic solvents (PDES) have shown great application prospects in research fields such as lithium-ion batteries, smart soft materials, and wearable devices. However, most of these materials currently face the challenge of difficult recycling and reuse, resulting in environmental pollution and resource waste. In this work, we introduced PDES made of acrylic acid (AA) and choline chloride (ChCl) into polymerizable ionic liquid monomers [ATAC][TFSI] and prepared a physically crosslinked multifunctional ionic conductive elastomer PIL-PDES through a simple and rapid “one-step” photopolymerization strategy. This elastomer not only has satisfactory mechanical properties (tensile strength: 3.93 MPa, elongation at break: 760 %), high transparency (80 %), strong adhesion (iron: 135 kPa) and rapid self-healing but can also be recycled and reused. Based on the good conductivity of the elastomer (conductivity: 2.49 × 10−3 S/m), it can be used not only as a sensor to monitor human activities and changes in environmental temperature but also as a biological electrode to record human electrocardiogram signals. We believe that due to its superior overall performance and simple preparation method, PIL-PDES has broad potential for practical application in flexible wearable electronic devices.

Porous activated carbons derived from waste Moroccan pine cones for high-performance adsorption of bisphenol A from water

Porous-activated carbons (ACs) derived from Moroccan pine cones (PC) were synthesised by a two step-chemical activation/carbonisation method using phosphoric acid (PC-H) and zinc chloride (PC-Z) as activating agents and used for the adsorption of bisphenol A (BPA) from water. Several techniques (TGA/DTA, FT-IR, XRD, SEM and BET) were used to determine the surface area and pore characterisation and variations during the preparation of the adsorbents. The modification significantly increased the surface area of both ACs, resulting in values of 1369.03 m2 g−1 and 1018.86 m2 g−1 for PC-H and PC-Z, respectively. Subsequent adsorption tests were carried out, varying parameters including adsorbent dosage, pH, initial BPA concentration, and contact time. Therefore, the highest adsorption capacity was observed when the BPA molecules were in their neutral form. High pH values were found to be unfavourable for the removal of bisphenol A from water. The results showed that BPA adsorption kinetics and isotherms followed pseudo-second-order and Langmuir models. Thermodynamic studies indicated that the adsorption was spontaneous and endothermic. Besides, the regeneration of spent adsorbents demonstrated their reusability. The adsorption mechanisms can be attributed to physical adsorption, hydrogen bonds, electrostatic forces, hydrophobic interactions, and π-π intermolecular forces.