Synthesis,Surface Properties and Antimicrobial Activity of Bolaamphiphile/Oppositely Charged Conventional Surfactant Mixed Systems

Four ionic bolaamphiphiles were synthesized from four bolasingle systems and the surface properties of bolasingle systems and bola\oppositely charged conventional mixed surfactant systems were studied. Variations in the structure of the hydrophobic chain of bolaamphiphiles has a great influence on their antimicrobial activities. The bolaform surfactants prepared have significant antimicrobial and antifungal activities relative to their conventional analogues. The Г_∞ (saturated adsorption amount) and A _min (minimum average area per surfactant molecule) of these bolaamphiphiles in both water and 0.1 M NaCl solutions were calculated and CMC of the mixed systems with oppositely charged conventional surfactants in both water and 0.1 M NaCl solutions were determined.

Influence of Sodium Ions on Micelles of Surfactin-C16 in Solution

The properties of surfactin-C₁₆ aqueous solution in the presence of Na⁺ ions, produced by Bacillus subtilis, were studied by the fluorescence method. The critical micelle concentration (CMC) of surfactin-C₁₆ was measured as 24.7 μM in 0.05 M Tris buffer (pH 8.5–8.6). With an increase in Na⁺ concentration, the CMC value and micropolarity of surfactin-C₁₆ decreased while the microviscosity increased, which means that the addition of Na⁺ improves the surface activity and enhances the micellization of the surfactin-C₁₆ in solution. The preliminary aggregation number (N) was obtained by the steady-state fluorescence method.

Synthesis and Biological Activity of 8-Hydroxyquinoline and 2-Hydroxypyridine Quaternary Ammonium Salts

Two series of quaternary cationic surfactant were synthesized by reaction of 8-hydroxyquinoline and 2-hydroxypyridine with long chain alkyl halides (dodecyl, tetradecyl- and hexadecyl-bromide). Surface tension was measured in aqueous solution for different concentrations at 25 °C. Various surface properties of the synthesized surfactants were evaluated, particularly critical micelle concentration (CMC), efficiency (Π_CMC) as well as maximum surface excess (Γ_max) and minimum surface area (A _min). Micellization and adsorption in liquid/air interfaces thermodynamics were investigated. The synthesized cationic surfactants were evaluated for their biocidal activity. All compounds prepared showed good antibacterial and antifungal activities.

Preparation and Application of Fluorinated Cationic Surfactants

Four fluorinated cationic surfactants were prepared by condensing 2,2,3,3, tetrafluoro-1-propyl chloroacetate with stoichiometric amounts of pyridine, 2-hydroxypyridine, 8-hydroxyquinoline and 8-hydroxyquinaldine to produce four quaternary ammonium salts. The surface and biocidal properties of these surfactants were investigated. Surface properties of their solutions including surface tension, critical micelle concentration (CMC), effectiveness (Π_cmc), maximum surface excess (Γ_max) and minimum surface area (A _min) were investigated with respect to different concentrations at 25 °C. Standard free energies of micellization and adsorption of the prepared surfactants in the aqueous solution were studied. The biocidal activity was determined via the inhibition zone diameter of prepared compounds which tested against six strains as a representative group of microorganisms.

Microwave-Assisted Synthesis and Properties of a Novel Cationic Gemini Surfactant with the Hydrophenanthrene Structure

A novel cationic gemini surfactant with the hydrophenanthrene structure has been synthesized from dehydroabietic acid by use of conventional thermal conditions and microwave irradiation. Its structure was confirmed by IR, ¹H NMR, and ¹³C NMR spectroscopy. It was found that microwave-assisted synthesis is an efficient means of preparation of this cationic gemini surfactant, with shorter reaction times and higher yields. The title compound had high surface activity. The CMC was 3.1 × 10⁻⁵ mol L⁻¹, γ _CMC was 26.3 mN m⁻¹, and emulsifying power (with benzene) reached five days. Comparison of this gemini surfactant and its monomeric counterpart proved the gemini surfactant was more surface active.

Surface Properties and Biological Activity of Select Cationic Surfactants

A series of cationic surfactants, N-(decyl N-tri-ethanol ammonium Bromide) (C₁₀), N-(dodecyl N-triethanol ammonium Bromide) (C₁₂), N-(hexadecyl N-triethanol ammonium Bromide) (C₁₆) were synthesized. These compounds have been evaluated by studying their surface properties, surface parameters, biodegradability and antimicrobial and antifungal activities.

Syntheses and Characterization of Some Cationic Surfactants

A series of novel cationic surfactants were synthesized from the quaternization of triethyl amine and various long chain alkyl halide. The chemical structure of the prepared compounds was confirmed using elemental analysis, FTIR and ¹H-NMR spectra. The physical properties of the synthesized surfactants including, electrical conductivity, critical micelle concentration, (CMC) and the degree of ionization of the micelle, (β) were studied. The thermodynamic parameters of micelle formation, standard free energy ΔG _m°, enthalpy ΔH _m°, and entropy ΔS _m° were calculated. The results of the surface parameter determination were correlated with their chemical structures. It was found that the hydrocarbon chain length is the main factor which has an effect on the value of the thermodynamic parameters.

The Synthesis of Oleic Acid Polyglycol Ester Catalyzed by Solid Super Acid

A SO₄ ²⁻/ZrO₂ super acid was prepared and the effect of different kinds of catalysts on the esterification reaction reviewed. The results showed that the SO₄ ²⁻/ZrO₂ super acid had higher catalytic activity and reactive selectivity in the synthesis of oleic acid polyglycol ester. Under optimum conditions the product was a monoester and the rate of production was more than 90%. The reaction product was characterized.

Degradation of Pesticides Wastewater by Silyl Based Cationic Surfactants

New stable silayl cationic surfactants have been studied for the destruction of toxic organophosphorus pesticides. Hexadecyl, dodecyl trimethyl silane ammonium chloride or iodide surfactants were synthesized and evaluated in the degradation of pesticides such as Diazinon, Malathion or Chlorpyrifos. The hydrolytic efficiency of each surfactant was tested by measuring the kinetics of model substrates cleavage under a pseudo-first order reaction. The iodo silayl based surfactants showed more destructive power than the chloro derivatives. Meanwhile, the hexadecyl moiety showed more effective pesticide degradation than the corresponding dodecyl moiety.

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Pure N-Alkylaminopropionic Acid and N-Alkylaminodipropionic Acid Sodium Salts: Synthesis, Characterization, and Physicochemical Properties

Fourteen pure β-aminopropionic acid amphoteric surfactants were synthesized from methyl acrylate using primary amines. The synthesis was done in two steps. First, Michael addition of a primary amine to methyl acrylate gave two separable addition products. Second, because the resulting esters gave, by the classical saponification procedure, undesired retro-Michael products, they were treated with sodium trimethylsilanolate to give the corresponding pure anhydrous acid salt under mild non-aqueous reaction conditions. Two types of amphoteric surfactants were obtained: the monocarboxylate and the dicarboxylate series. The pure surfactants were characterized by IR, ¹H NMR, and ¹³C NMR spectroscopy. The surfactant critical micelle concentrations were evaluated. From these the Gibbs free energy of micellizations [∆G(–CH₂–)_mic] were calculated. These are related to the methylene units that contribute an average of −1.0 (±0.3) kJ mol⁻¹ for both the monocarboxylate and the dicarboxylate series.

Surface and Biological Activity of Some Novel Cationic Surfactants

In this study, steps were taken toward the development of bactericidal and fungicidal synthetic cationic surfactants by reacting decyl, dodecyl or tetradecyl amine with acetic or hydrochloric acid to produce a series of amine salts which consequently converted to copper or cobalt cationic complexes via complexing the first series compounds with copper (II) or cobalt (II) ions. Surface properties such as interfacial tension and emulsifying power of these surfactants were investigated. The surface parameters including critical micelle concentration (CMC), maximum surface excess (Γ_max) and minimum surface area (A _min) were studied. Free energy of micellization (ΔG°_mic) and adsorption (ΔG°_ads) were calculated. The antimicrobial activity was determined via the inhibition zone diameter of the prepared compounds, which measured against five strains of a representative group of microorganisms. FTIR spectra, elemental analysis and H¹ NMR spectrum were performed to confirm compound structure and purity.

Preparation,Surface-Active Properties and Antimicrobial Activities of Bis(Ester Quaternary Ammonium) Salts

New cationic surfactants, bis-quaternary ammonium salts, were prepared from N,N-dimethylaminoalkyl esters of saturated fatty acids and products of the reactions of epichlorohydrin with primary amines: pentyl-, hexyl- and octylamine. The bis (ester–ammonium) salts obtained were examined in respect to their surface-active properties: critical micelle concentration (CMC), effectiveness of surface tension reduction (γ_CMC), and adsorption efficiency (pC₂₀). All these surfactants showed good water solubility and low critical micelle concentrations of more than two orders of magnitude lower than these of corresponding mono-alkylammonium salts. They also showed good wetting capability, but worse foaming properties. All the surfactants tested were nontoxic to gram-negative bacteria, but some of them inhibited the growth of gram-positive bacteria and yeast.

Synthesis of Cleavable Aryl Sulfonate Anionic Surfactants and a Study of their Surface Activity

A series of cleavable aryl sulfonate anionic surfactants were synthesized from cyanuric chloride, aliphatic amine and H-acid mono sodium salt. Their structures were identified by ¹H NMR, Infrared Spectrum (IR) and Elementary Analysis (EA). Their critical micelle concentrations (CMC) in aqueous solutions at 25 °C were determined by a steady-state fluorescence probe method and a surface-tension method. With the increasing length of the carbon chain, the value of their CMCs and surface tensions under CMC (γ _CMC) initially decreased and then reached a minimum (respectively 2.63 × 10⁻⁵ mol L⁻¹ and 28.29 mN m⁻¹) when the carbon number was 10. The CMC and γ _CMC then increased when the carbon number was increased to 12. The results showed that, compared with sodium dodecyl benzene sulfonate (SDBS), such kinds of surfactants have much lower surface adsorption amounts and greater molecular areas on the aqueous surface.

Overexpression of a FAD3 Desaturase Increases Synthesis of a Polymethylene-Interrupted Dienoic Fatty Acid in Seeds of <Emphasis Type="Italic">Arabidopsis thaliana</Emphasis> L.

A cDNA encoding the Arabidopsis extraplastidic linoleate desaturase (FAD3) was overexpressed in the seeds of wild-type Arabidopsis and in a mutant line that accumulates high levels of oleic acid. In the transformed wild-type plants, linolenic acid (18:3Δ9,12,15) increased from 19% to nearly 40% of total seed fatty acids, with a corresponding decrease in linoleate content (18:2Δ9,12). In the high oleate mutant, a large increase in the level of a fatty acid identified by gas-chromatography/mass-spectrometry as mangiferic acid (18:2Δ9,15) was observed. The results demonstrate that the polymethylene-interrupted dienoic fatty acid, mangiferic acid, can be produced in seed oil through the overexpression of a fatty acid n-3 desaturase.

A Study of the Technical Route of the Synthesis of Alkylbenzenes for Use as an Oil Displacement Agent

This paper describes the technology of synthesizing alkylbenzenes containing C_16–19 alkyl chains. The heavy alkylbenzenes were prepared by C_16–19 liquid paraffin dehydrogenation, followed by alkylation with benzene. A novel catalyst containing Pt and Sn as its main components for the dehydrogenation of C_16–19 paraffins to alkenes was prepared by vacuum impregnation and the catalyst exhibited high stability and selectivity. The alkylation of the C_16–19 alkenes and benzene had a conversion yield of 86.15% and a selectivity of 81.21%. The main alkylbenzenes was identified as monoalkylbenzene by IR and chromatography analysis. C_16–19 alkylbenzene sulfonates are found to give an ultra-low interfacial tension when mixing with crude oil/reservoir water.

Synthesis, Characterization and Biological Activity of Sugar-Based Gemini Cationic Amphiphiles

Two series of gemini cationic surfactants were synthesized based on glucose and fructose molecules. Their chemical structures were confirmed using micro-elemental analysis, mass spectral fragmentation and FTIR spectroscopic analysis. The surface activities of these gemini amphiphiles were measured, including surface tension (γ), critical micelle concentration (CMC), effectiveness (π _cmc), efficiency (pC₂₀), maximum surface excess (Γ_max) and minimum surface area (A _min) at 25 °C. Adsorption and micellization free energies of these amphiphiles in their solutions showed a good tendency towards adsorption at the interfaces. The biological activity of the synthesized gemini amphiphiles showed good inhibition at concentrations of 1, 2.5 and 5 mg/mL. The synthesized amphiphiles showed antimicrobial activity on gram-positive and gram-negative bacteria and antifungal activity equal to or comparable to commercially available controls. The discussion rationalized the antimicrobial activities of these amphiphiles with the surface activity and the adsorption parameters. In addition, the effect of sugar nuclei was discussed based on the chemical structure of the bacterial and fungal cell membranes.

Synergistic Behavior of a Triblock Copolymer with Anionic and Cationic Surfactants in Aqueous Solution

The synergistic behavior of poly(ethylene oxide)–poly(propylene oxide)–poly(ethylene oxide) (PEO–PPO–PEO) triblock copolymer in aqueous solution with the synthesized anionic surfactants [decyl sulfonate (A10), myristyl sulfonate (A14) and cetyl sulfonate (A16)] and cationic surfactants [decyl pyridinium bromide (C10), myristyl peridinium bromide (C14) and cetyl pyridinium bromide (C16)] was investigated using a surface tension technique at 25 °C. The results show that the CMC values of binary mixtures for anionic and cationic surfactants with the triblock copolymer are lower than that of single surfactants. The synergistic interaction between surfactant molecules and copolymer molecules in binary mixed solution enhance the adsorption of surfactant molecules at the interface. The micellar mole fractions (X _m) and the interaction parameter (β) of these surfactants in mixed micelles were determined.

Synthesis of nano crystalline zeolite Y from bentonite

Zeolite Y was synthesized from bentonite via the hydrothermal method. The effects of various parameters on the synthesis were investigated. The samples were characterized by XRD, XRF, IR, DTG and wet chemical analysis. The results show that crystallization temperature, aging time and concentration of sodium hydroxide play important roles in the formation of the zeolite. P zeolite was the competitive phase and present in most of the products. However, under optimized conditions, such as crystallization temperature (97 °C), aging time (20 h), concentration of NaOH (3N), pure zeolite Y with high crystallinity was synthesized. The results showed that optimization of the process results in a commercial route to synthesis zeolite Y from bentonite.

Spacer Effects in Novel Cationic Surfactants as a Primordial Parameter for an Optimal Inhibition of SRB

Four bisquaternary ammonium surfactants, low toxic compounds capable of inhibiting sulfate-reducing bacteria (SRB), were synthesized and characterized by spectral studies IR, ¹H-NMR and elemental analyses. The growth of the reference SRB (Desulfomonas pigra) was shown to be completely inhibited by bisquaternary ammonium surfactants. Structure–activity relationships are discussed, as well as the critical micelle concentration (cmc), the saturated adsorption amount (Г_∞) and the minimum average area per surfactant molecule (A _min). The influence of the hydrophobic chain length, the number of methylene groups, and the influence of that spacer group on the surfactant properties of synthesized bisquaternary ammonium compounds are discussed. The presence of a long hydrophobic alkyl chain was a primordial parameter for optimal biological activity. The number of SRB and their inhibition efficiency were subject to considerable parameters, maximum values being noted in presence of all paper biocides. A direct relationship has found between the number of SRB and A _min.

Synthesis of Unsymmetrical Bolaform Surfactants with a Sulfonate Group and a Carboxyl Group

Three unsymmetrical bolaform surfactants with different aromatic rings and a ω-carboxyalkyl chain were synthesized and their molecular structures were characterized by ESI–MS and ¹H NMR. The percentages of conversion of alkylation were judged by the iodine value measurements and the effect of reaction temperature on sulfonate content of synthesized products has also been discussed.