Chemo-enzymatic synthesis and properties of novel optically active cationics containing carbonate linkages

Novel optically active carbonate-type cationics were designed and synthesized via a green method. A series of n-alkyl N,N-dimethylaminoalkyl carbonates was prepared via a two-step successive carbonate exchange reaction of diphenyl carbonate with 1-alkanol followed by the reaction of the optically active or racemic amino alcohol in the presence of triethylamine. The quaternarization of the N,N-dimethylamino group was carried out using methyl iodide. Furthermore, optically active cationics were prepared by the lipase-catalyzed enantioselective hydrolysis of the racemic cationics. Carbonate-type cationics having an isopropylene linkage showed high hydrolytic stability. They exhibited surfactant properties similar to those of the corresponding racemic cationics. Although no significant differences in the antimicrobial activities were observed owing to the stereochemistry of the cationics, the biodegradability was strongly influenced by the stereochemistry. Some optically active cationics were rapidly biodegraded by activated sludge.     

Synthesis and properties of biodegradable and chemically recyclable cationic surfactants containing carbonate linkages

Novel biodegradable and chemically recyclable carbonate-type cationic surfactants consisting of a long chain alkyl group and a quaternary ammonium propyl group were designed and synthesized as a green surfactant. These carbonate-type cationics showed better surface activities in an aqueous solution when compared to the conventional cationics. Novel cationics containing both the carbonate linkage and n-dodecyl group showed strong antimicrobial properties, enzymatic degradabilities for chemical recycling and rapid biodegradabilities by activated sludge.     

Synthesis and Properties of Gemini-type Cationic Surfactants Containing Carbonate Linkages in the Linker Moiety Directed Toward Green and Sustainable Chemistry

Gemini-type cationic surfactants containing carbonate linkages as biodegradable and chemically recyclable segments, consisting of two long-chain alkyl groups, two quaternary ammonium groups and a linker moiety, were designed and synthesized as novel green and sustainable cationics with improved physicochemical and biological activities. The gemini-type cationics containing a carbonate linkage showed lower critical micelle concentration values compared to the corresponding single-type cationics. Also, the gemini-type cationics containing a carbonate linkage in the linker moiety showed strong antimicrobial activities. The biodegradability of the gemini-type cationics was significantly improved when a carbonate linkage was introduced into the linker moiety. The maximum biochemical oxygen demand-biodegradability of the gemini-type cationics containing a carbonate linkage in the linker moiety exceeded 70% after a 28-day incubation. Furthermore, the gemini-type cationics containing both a carbonate linkage and an n-dodecyl group showed a chemical recyclability using a lipase (E.C. 3.1.1.3).

Synthesis and properties of new cationic surfactants. II. Odd homologous members

In connection with our previous work on the synthesis and study of new pyrimidinium cationic surfactants, some new members of the N-alkyl-pyrimidinium salts homologous series were prepared. The above compounds contain long-chain alkyl groups of 7, 9, 11, 13, 15, 16, 17 and 18 carbon atoms. The series of these compounds having an alkyl chain of C₇–C₁₈ has been completed, and a correlation between their constitution and some properties has been made. The structural assignment of these compounds was made on the basis of the elemental analysis and IR, NMR, MS spectroscopic data. Surface tension, water solubility and antimicrobial activities were determined for these surfactants. The wet fastness of direct dyed cotton fabrics after-treated with these cationics also was studied.     

Creation of Novel Green and Sustainable Gemini-Type Cationics Containing Carbonate Linkages

Novel gemini-type cationics containing carbonate linkages as biodegradable and chemically recyclable segments were designed and synthesized by a green process. The carbonate linkages were introduced into only the hydrophobic moiety or in both the hydrophobic and linker moieties of gemini-type cationics. They showed higher surface activities, such as a low critical micelle concentration value, a surface tension lowering, and a high adsorption efficiency, when compared to the corresponding single-type cationics. Also, the gemini-type cationics containing carbonate linkages in both the hydrophobic and the linker moieties showed stronger antimicrobial activities when compared to those only in the hydrophobic moiety. It was found that some gemini-type cationics containing carbonate linkages showed higher biodegradability compared to the conventional gemini-type cationics. The biodegradability of the gemini-type cationics decreased when a carbonate linkage was introduced into the hydrophobic moiety rather than the linker moiety. However, some gemini-type cationics containing carbonate linkages both in the hydrophobic and linker moieties showed ready biodegradability. The gemini-type cationics containing carbonate linkages in the hydrophobic moiety showed chemical recyclability by a lipase (E.C. 3.1.1.3).     

Preparation and properties of a new type of carbohydrate-based cationic surfactant

A new type of cationic surfactant, 6-O-monoesters of 3-(trimethylammonio)propyl d-glucopyranoside, was prepared in high yield by a simple chemoenzymatic synthesis. Surface-active properties of the compounds were found to be highly dependent on the fatty acyl chain length in the 6-O-position with the dodecanoyl and tetradecanoyl esters exhibiting the highest ability to lower surface tension as well as having the lowest critical micelle concentration values. Furthermore, the dodecanoyl ester had excellent foaming properties. The new surfactants also showed antimicrobial activity. Thus, the most potent compound, the dodecanoyl ester, was able to inhibit growth of both bacterial (Gram-positive as well as Gram-negative) and fungal test strains. The antimicrobial effect was somewhat weaker compared to benzalkonium chloride, one of the most frequently used cationics for topical disinfection. However, compared to benzalkonium chloride, the new cationics exhibit a highly improved compatibility with anionic surfactants, as no precipitation took place even in highly concentrated solutions thereby providing a much more robust antimicrobial system. Finally, the new surfactants are expected to be readily biodegradable because they are carbohydrate ester-based.     

Chemical Synthesis and Characterization of Novel Antibacterial Polycyclic Polymer

Polyaniline (PAn) and poly(alkyl substituted anilines) were synthesized in aqueous media by chemical polymerization of alkyl substituted aniline in presence of ammonium peroxydisulphate as an oxidant. The products were investigated in terms of morphology, chemical structure, and mechanism of polymerization with scanning electron microscope (SEM), transmission electron microscopy (TEM), fourier transform infrared (FTIR), and UV–visible spectroscopy (UV–vis), respectively. Results indicated that physicochemical properties of poly(alkyl substituted anilines) depend on substituent groups bonded to N-position. In general, alkyl-substituted PAn have similar chemical and optical properties to parent PAn and it seems that the substituted PAn follow the same polymerization mechanism as reported for PAn. The prepared polymers were then tested for the antibacterial properties against Gram-negative bacteria: Escherichia coli (E. coli). The antibacterial properties were assessed by measuring the zones of inhibition. The antimicrobial results showed clearly that PAn and poly(alkyl substituted anilines) exhibited excellent antibacterial activity against the growth of E. coli microorganism.     

Pyrimidinium cationic surfactants as emulsifiers for oil-in-water emulsions

Pyrimidinium cationic surfactants with 13–17 carbon atoms in the hydrophobe were used as emulsifiers for oil-inwater (heptane/water) emulsions at concentrations near the critical micelle concentrations. Interfacial tensions of the emulsifier solutions in water against heptane were measured. Drop size distributions of the emulsions were determined at different times using microscopic techniques, and the rate of coalescence was calculated. The structure having 16 carbon atoms in the alkyl chain had coalescence rates lower than the other structures, including two conventional C-16 cationics used as controls.     

Synthesis and Properties of Dissymmetric Gemini Surfactants

A series of novel dissymmetric gemini cationics surfactants was synthesized by three-step reactions. The dissymmetric gemini surfactants contain a dodecanoic acid dimethylethylamine ester as the constant cationic part on one side of the hydroxypropyl center and a similar other cationic part, but with a different acid length (from octanoic to palmitic), on the other side. The critical micelle concentration (CMC) and the effectiveness of surface tension reduction (γ _CMC) were determined. The surface tension measurements of dissymmetric gemini surfactants showed good water solubility, and low CMC had great efficiency in lowering the surface tension and a strong adsorption at the air/water interface. The CMC was observed to increase initially with the increase of the ester bond alkyl group. They also showed good foaming properties and wetting capabilites.     

Synthesis and characterization of antimicrobial cationic surfactants: Aminopyridinium salts

Three antimicrobial 4-aminopyridinium salts were synthesized using two different processes in an effort to develop antimicrobial surface treatment agents for wool fibers. The structures of the salts were fully characterized using Fourier transform infrared, ¹H nuclear magnetic resonance (NMR), and ¹³C NMR analysis. In addition, their thermal stability was determined using differential scanning calorimetry and thermogravimetric analysis. The antimicrobial efficacy of these compounds was evaluated using minimum inhibitory concentration as an indicator. All of the synthesized aminopyridinium salts showed antimicrobial activity against gram-negative bacteria, but in different levels depending on their structures. The salts possessing longer alkyl chains demonstrated better antimicrobial function. The melting points of the salts decreases as the alkyl chain length increases.     

Surface activities,biodegradability and antimicrobial properties of n-alkyl glucosides,mannosides and galactosides

n-Alkyl α-and β-glucopyranosides, α-D-mannopyranosides and β-D-galactopyranosides with alkyl chains having from 8 to 12 carbon atoms were synthesized and their surface properties-such as static surface tension (γ), critical micelle concentration (CMC), occupation area of molecule, dynamic surface tension and foaming properties, biodegradability and antimicrobial activities—were evaluated. Alkyl glycosides containing C8 to C12 carbon chains showed surface activities and critical micelle concentrations. D-Glucoside, D-mannoside and D-galactoside having the same alkyl chain showed similar surface tension lowering at CMC (γ_CMC) and occupation area of the molecule at the surface. Among the alkyl glucosides, α-anomers were less hydrophilic than β-anomers. All alkyl glycosides tested in this study were readily biodegraded by activated sludge of a municipal sewage plant compared to those of ethoxylated nonionic alcohols. The difference of the hydrophilic glycopyranoside group in biodegradability was not seen clearly. n-Alkyl glycosides containing C8 to C12 alkyl chains showed a broad spectrum of increasing antimicrobial activity. n-Dodecyl α-D-mannopyranoside was the most effective, the order of antimicrobial activity being mannopyranoside > glucopyranoside > galactopyranoside group. Members of this class of compounds exhibit the physicochemical and biological properties needed both for a wide range of applications and for environmental acceptance.     

Synthesis and Characterization of Cationic Surfactants Based on N‐Hexamethylenetetramine as Active Microfouling Agents

Four cationic surfactants of quaternary hexammonium silane chloride based on hexamethylenetetramine and alkyl chloride were synthesized. The chemical structures of the prepared cationic surfactants were elucidated using Fourier transform infrared (FT‐IR) spectroscopy and mass spectrometry analysis. The surface and thermodynamic properties of the prepared surfactants were also studied. The performance of these cationic surfactants as microfouling agents against two strains of Gram‐negative bacteria, namely, Pseudomonas aeruginosa and Escherichia coli, and two strains of Gram‐positive bacteria, namely, Staphylococcus aureus and Bacillus subtilis, were evaluated as antimicrobial agents. The results showed that the maximum antimicrobial activity was detected for N‐hexamethylenetetramine‐N‐ethyl silane ammonium trichloride (Ah). The maximum and minimum antimicrobial activities were 73 and 60 % against S. aureus and E. coli, respectively, at a concentration of 5 mg/l, pH 7, and 37 °C.     

Surface modification and antimicrobial properties of cellulose nanocrystals

A novel and simple surface modification of cellulose nanocrystals (CNC) was performed by chloroacetylation and subsequent reaction with tertiary amines to form quaternary ammonium modified CNCs. The acetylation of CNC and quaternary ammonium modified CNCs was confirmed using IR spectroscopy and solid state NMR spectroscopy. The ¹³C NMR spectrum of quaternary ammonium modified CNC showed several additional resonances ranging from 14.5 ppm to 58.0 ppm compared to ¹³C NMR spectrum of pure CNC, suggesting that alkyl chains have been added to the pure CNC. The disc diffusion method was used to evaluate the antimicrobial properties of quaternary ammonium modified CNCs. It was found that modified CNCs with alkyl chain longer than ten carbons are effective antimicrobial agents against Staphylococcus aureus and E. coli bacteria. These CNCs can be chemically modified to tailor the properties to improve dispersion in the polymer matrix. This will expand the application of CNC as a reinforcing material. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44789.     

Surface-Active Properties and Antimicrobial Study of Conventional Cationic and Synthesized Symmetrical Gemini Surfactants

Symmetrical gemini surfactants of cationic series α,ω-alkanediyl bis (dimethyl ammonium bromide) commonly referred as “m–s–m” have been synthesized. Spectral analysis was performed to confirm compound structures and purity. Conductivity and surface tension measurements provide better understanding of the micellization process. Their self-assembly behavior in aqueous solution is also discussed in detail. The antimicrobial efficacy was measured by bacterial and fungal growth inhibition expressed as minimal inhibitory concentration values against five strains of a representative group of microorganisms viz. Bacillus subtilis, Staphylococcus aureus, Klebsiella pneumonia, Salmonella paratyphi B and Aspergillus niger. All of the synthesized surfactants showed antimicrobial activity against them, but at different levels depending on their structures. The surfactants possessing longer alkyl chains (more hydrophobic environment) demonstrated better antimicrobial functionality. The antimicrobial potency was found to be dependent on the representative target microorganism (Gram-positive bacteria > fungi > Gram-negative bacteria), as well as on the ionic nature of the surfactant (cationic), alkyl chain length (m = 12, 16) and spacer length (s = 2, 4, 6) of the synthesized compounds. Gemini surfactants such as 12-2-12 and 12-4-12 were found to be weakly active whereas 16-2-16 and 16-4-16 compounds proved to be the most potent antimicrobial surface-active agents among the synthesized gemini homologues.     

Surface activities,biodegradability and antimicrobial properties of glucosamine derivatives containing alkyl chains

Three series of D-glucosamine derivatives containing an alkyl chain with 8 to 14 atoms, methyl 2-acylamino-2-deoxy-D-glucopyranosides,n-alkyl 2-acetylamino-2-deoxy-D-glucopyranosides andn-alkyl 2-amino-2-deoxy-D-glucopyranoside hydrochlorides, were synthesized, and their surface properties (such as surface tension, critical micelle concentration (CMC), dynamic surface tension and foaming properties), biodegradability and antimicrobial activities were evaluated.n-Alkyl 2-amino-2-deoxy-D-glucopyranoside hydrochlorides containing C8 to C12 carbon chains showed surface activities, a CMC and excellent foaming properties. The α-anomers showed a slightly lower CMC than the β-anomers, indicating less hydrophilicity of the α-anomers. On the other hand, glucosamine derivatives containing amide groups showed poor surface activities in water due to their lower solubilities in water. All glucosamine derivatives containing alkyl chains were biodegraded as well as conventional ethoxylated nonionics by activated sludge from the municipal sewage treatment plant. Methyl 2-acylamino-2-deoxy-D-glucopyranosides andn-alkyl 2-amino-2-deoxy-D-glucopyranoside hydrochlorides showed a broader spectrum of antimicrobial activity than the correspondingn-alkyl glucopyranosides. Among them the C12 derivatives showed the best results.     

Synthesis and antimicrobial activity of quaternary ammonium-functionalized POSS (Q-POSS) and polysiloxane coatings containing Q-POSS

An array of quaternary ammonium-functionalized POSS (Q-POSS) compounds were synthesized and their antimicrobial properties toward the Gram-negative bacterium, Escherichia coli, and the Gram-positive bacterium, Staphylococcus aureus, determined in aqueous solution. Using Q-POSS compositions that exhibited broad spectrum antimicrobial activity in solution, the utility of the Q-POSS compounds as an antimicrobial additive for polysiloxane coatings was determined. The results of the investigation showed that Q-POSSs possessing a relatively low extent of quaternization and longer alkyl chain lengths provided the highest antimicrobial activity in solution. For polysiloxane coatings containing Q-POSS molecules as an antimicrobial additive, coating surface energy, surface morphology, and antimicrobial properties were found to be strongly dependent on Q-POSS composition. Coatings based on Q-POSSs possessing the lowest extent of quaternization displayed antimicrobial activity while analogous coatings produced using Q-POSSs possessing the highest extent of quaternization showed no antimicrobial activity. The lack of antimicrobial activity exhibited by coatings possessing Q-POSSs with a relatively high extent of quaternization was attributed to agglomeration of Q-POSS molecules through the formation of intermolecular interactions involving the quaternary ammonium moieties. Agglomeration would be expected to reduce diffusivity and inhibit interaction of the Q-POSS molecules with microbial cells.     

Characteristic properties of cutting fluid additives derived from fatty alcohols

Many 3-aminopropyl alkyl ethers were prepared and their characteristics as water-based cutting fluids were examined. 3-Aminopropyl octyl-, decyl- and dodecyl ethers showed good lubricities and antimicrobial properties for a water-based cutting fluid.     

Analysis of mixtures of ionic and nonionic surface-active agents. Separation and recovery of components by batch ion exchange

Mixtures of anionic and nonionic surfactants or cationic and nonionic surfactants can be separated by stirting an aqueous solution of the mixture with a small amount of a strong anion exchange or strong cation exchange resin, respectively. The resin-ionic surfactant complex is removed by filtration and washed; the nonionics are recovered from the filtrate and washings. By suitable treatment the ionic surfactants can be removed selectively from the resin. In the case of anionic surfactants, soaps, alkyl sulfates, and alkylaryl sulfonates can successively be removed from the resin; with cationics, nonquaternary and quaternary surfactants can be selectively removed. Results obtained with various mixtures of surface active agents are discussed. Presented at the 51st fall meeting, American Oil Chemists’ Society, New York, October 17–19, 1960.     

Synthesis, surface-active properties, and antimicrobial activities of new double-chain gemini surfactants

A novel series of neutral and cationic dimeric surfactants were prepared involving ketalization reaction, Williamson etherification, and regioselective oxirane ring opening with primary and tertiary alkyl amines. The critical micelle concentration (CMC), effectiveness of surface tension reduction (gamma(CMC)), surface excess concentration (Gamma), and area per molecule at the interface (A) were determined and values indicate that the cationic series is characterized by good surface-active and self-aggregation properties. For the first time, we reported the antimicrobial activities against representative bacteria and fungi for dimeric compounds. The antimicrobial activity was found to be dependent on the target microorganism (Gram-positive bacteria > fungi > Gram-negative bacteria), as well as both the neutral or ionic nature (cationic > neutral) and alkyl chain length (di-C(12) > di-C(18) > di-C(8)) of the compounds. The cationic di-C(12) derivative was found to have equipotent activity to that of benzalkonium chloride (BAC) used as standard.     

Antimicrobial Properties and Cytotoxic Effect of Imidazolium Geminis with Tunable Hydrophobicity

Antimicrobial, membranotropic and cytotoxic properties of dicationic imidazolium surfactants of n-s-n (Im) series with variable length of alkyl group (n = 8, 10, 12, 14, 16) and spacer fragment (s = 2, 3, 4) were explored and compared with monocationic analogues. Their activity against a representative range of Gram-positive and Gram-negative bacteria, and also fungi, is characterized. The relationship between the biological activity and the structural features of these compounds is revealed, with the hydrophobicity emphasized as a key factor. Among dicationic surfactants, decyl derivatives showed highest antimicrobial effect, while for monocationic analogues, the maximum activity is observed in the case of tetradecyl tail. The leading compounds are 2–4 times higher in activity compared to reference antibiotics and prove effective against resistant strains. It has been shown that the antimicrobial effect is not associated with the destruction of the cell membrane, but is due to specific interactions of surfactants and cell components. Importantly, they show strong selectivity for microorganism cells while being of low harm to healthy human cells, with a SI ranging from 30 to 100.