Sulfated Zirconium Catalyst for Synthesis of Dialkylated Diphenylether Disulfonate Gemini Surfactants

Dialkylated diphenylether disulfonate with different alkyl chain lengths (C_n‐DADS, n = 8, 10 and 12) has been synthesized by Friedel‐Crafts alkylation of olefins (C₈, C₁₀ and C₁₂) and diphenyl oxide, followed by sulfonation and neutralization with fuming sulfuric acid. Sulfated zirconia solid acids were prepared and used to catalyze the alkylation reaction. The structure of sulfated zirconia solid acids was identified by infrared spectroscopy. The title compounds were confirmed by infrared spectroscopy and electrospray ionization‐mass spectrometry. Equilibrium surface tension measurements show that the critical micelle concentration (CMC) decreases with an increase in chain length, and the surface tension at CMC (γ_cmc) of C₈‐DADS is the lowest. The minimum area per molecule (A_min) values of C_n‐DADS increase, while the surface excess concentration (Γ_max) values decrease with the increase of the alkyl chain length. C₁₀‐DADS has the highest pC₂₀ and CMC/C₂₀ among C_n‐DADS.     

Toughening of cycloaliphatic epoxy resin improved by reactive copolymers with flexible alkyl side chains

Reactive copolymers with flexible alkyl side chains were used as modifiers to improve the toughness of a cycloaliphatic epoxy resin. In this study, we used three types of copolymers with different alkyl chain length (C₄H₉, C₆H₁₃, and C₁₀H₂₁). As a result, the system with an added copolymer having the longest alkyl chain length (C₁₀H₂₁) formed a phase separation structure. The addition of this copolymer (C₁₀H₂₁) led to a 50% increase in the fracture toughness (K_IC) of the cured resin at the slight expense of its glass transition temperature. Scanning electron microscope observations in the vicinity of a crack tip after a compact tension test showed that cavitation of the dispersed phase occurred. The crack growth was inhibited and thus the toughness was improved due to the plastic deformation of the epoxy matrix followed by cavitation. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

The Influence of Alkyl Chain Length and Steric Effect on Extraction of Zinc(II) Complexes with 1‐Alkyl‐2‐Methylimidazoles

Abstract

The extraction of Zn(II) complexes with six 1‐alkyl‐2‐methylimidazoles (alkyl is from C₅H₁₁ up to C₁₂H₂₅) from nitric solution was studied as a function of pH of the aqueous phase. As the organic solvents toluene, p‐xylene and 1,2,3,4‐tetrahydronaphthalene were used. The stability constants of the complexes in the aqueous phase as well as partition constants of the extractable species were determined. It was demonstrated that both the stability constants (β_c) and the partition constants (P_c) of the complexes increased with increasing alkyl chain length. Pseudo‐tetrahedral complexes were found to dominate at the second and third complexation steps, thus increasing the stability constants and facilitating extraction of the Zn(II) complexes with 1‐alkyl‐2‐methylimidazoles.     

The Influence of the Alkyl Chain Length and Steric Effect on Stability Constants and Extractability of Co(II) Complexes with 1‐Alkyl‐4(5)‐methylimidazoles

Abstract

Extraction of Co(II) complexes has been studied with nine derivatives of 1‐alkyl‐4(5)‐methylimidazoles (with R=C₂H₃ to C₁₀H₂₁) from aqueous solution [I=0.5(KNO₃) at 25°C] with toluene, trichloromethane, and 2‐ethyl‐1‐hexanol. Stability constants of the complexes formed in the aqueous phase (β _c ) as well as partition constants (P _c ) of the extracted species were determined. It was demonstrated that both the stability constants and partition constants of the complexes increase with an increasing of the 1‐alkyl chain length. The tetrahedral together with octahedral complexes were formed beginning from the second step of complexation. Furthermore, the influence of the bulkiness of the 1‐alkyl group on separation process of Co(II) from Zn(II) for extractions with toluene and 2‐ethyl‐1‐hexanol were determined.     

Development of technologies for producing high-octane ethers

To produce alkyl(C₁-C₂)-tert-alkyl(C₄-C₇) ethers, different process designs are necessary depending on the raw materials and production rate. New production processes using catalytic distillation and cocurrent reactors are described and compared with conventional processes. The justification of the choice of efficient flow diagrams, reactors, and new methods for recovering C₁-C₂ alcohols from hydrocarbon product streams is given.     

Comparison of antimicrobial activities of polyacrylonitrile fibers modified with quaternary phosphonium salts having different alkyl chain lengths

A series of polyacrylonitrile fibers (PANF) modified with quaternary phosphonium salts having various alkyl chain lengths (C₁, C₂, C₆, C₈, C₁₂) were synthesized and compared for their antimicrobial activities by the improved shake flask method. The as‐prepared fibers were named MTPB‐PANF, ETPB‐PANF, HTPB‐PANF, OTPB‐PANF, and DTPB‐PANF, respectively. The representative microorganisms employed were Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), Pseudomonas aeruginosa (P. aeruginosa), and Candida albicans (C. albicans). Results from the current study showed that the alkyl chain length of quaternary phosphonium salts not only affected the synthesis of the fibers, but also impacted their antimicrobial activities. There was a rule that the longer the alkyl chain length, the more easily the quaternary phosphonium salts modify the fibers and the better the antimicrobial activities of the modified fibers. All the modified fibers exhibited good broad‐spectrum antimicrobial activities. Specifically, DTPB‐PANF exhibited an outstandingly high antimicrobial activity, which was nearly unaffected by the environmental pH (3–10). It can kill all the four pathogens in 15 min and had an excellent wash‐resistant property. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43689.     

Contact angle of surfactant solutions on precipitated surfactant surfaces

In this study, the contact angle of a saturated aqueous surfactant solution onto the surface of a precipitate of that surfactant is investigated. Those precipitates include fatty acids (C₁₀, C₁₂, C₁₄, C₁₆, and C₁₈), sodium salts of fatty acids (C₁₄, C₁₆, and C₁₈), calcium salts of fatty acids (C₈, C₁₀, C₁₂, C₁₄, C₁₆, and C₁₈). On virgin surfaces, free fatty acids and calcium salts of fatty acids have advancing contact angles (θ_A) between 77 and 92°, with little dependence on alkyl chain length for C₁₂ and higher alkyl chains. The sodium salt of a fatty acid has a lower θ_A than the free fatty or the calcium salt of the soap. The calcium salt of dodecyl sulfate has a lower θ_A than the calcium salt of dodecanoic acid (θ_A = 46 vs. 82°), but the calcium salt of the 18-carbon hydrophobes showed nearly the same contact angle for the soap and the alkyl sulfate. Greasiness, or slipperyness, or a scummy feel of a precipitated surfactant does not necessarily correspond to a hydrophobic surface.     

Comparison of the Composition and Structural Parameters of W/O Microemulsions Containing Gemini Imidazoliums with Those Containing Monomeric Analogues

The composition and structural parameters of W/O microemulsions containing the gemini surfactant 1,4‐bis(3‐alkylimidazolium‐1‐yl) butane bromide [(C_n‐4‐C_n)Br₂, n = 12, 14, 16] + pentan‐1‐ol + octane + water and W/O microemulsions containing the ionic liquid surfactant 1‐alkyl‐3‐methylimidazolium (C_nmimBr, n = 12, 14, 16) + pentan‐1‐ol + octane + water were studied and compared. The mole fractions of the n‐alkyl alcohol at the interfacial layer in (C_n‐4‐C_n)Br₂ based microemulsion systems are always larger than those in C_nmimBr based microemulsion systems. However, the mole fractions of the n‐alkyl alcohol in the oil phase are nearly the same for both the microemulsion systems. The (C_n‐4‐C_n)Br₂ based microemulsion systems have greater absolute values of the free enthalpy values than that for C_nmimBr based systems. In the (C_n‐4‐C_n)Br₂ based microemulsion systems, a large number of cosurfactants at the interfacial layer is conducive to the formation of a smaller droplet W/O microemulsion. The effects of n‐alkyl alcohols, alkanes, salinity and temperature on the composition and structural parameters of the (C_n‐4‐C_n)Br₂ based and C_nmimBr based microemulsion systems were also investigated and discussed.     

Contact angle of surfactant solutions on precipitated surfactant surfaces. II. Effects of surfactant structure,presence of a subsaturated surfactant,pH, and counterion/surfactant ratio

The contact angle of a saturated aqueous surfactant solution on the precipitate of that surfactant was measured by using the sessile drop method. The sodium and calcium salts of alkyl sulfates (C₁₂, C₁₄, and C₁₈) had advancing contact angles higher than those of alkyl trimethylammonium bromides (C₁₄, C₁₆, and C₁₈). The measured advancing contact angles for several surfactant solutions did not substantially change with varying surfactant/counterion ratios; therefore, the precipitating counterion concentration (e.g., water hardness) had little effect on the wettability. The contact angles of fatty acid (C₁₂ and C₁₆) solutions did not show any dependence on pH between a pH of 4 and 10. The contact angles of saturated calcium dodecanoate (CaC₁₂) solutions containing a second subsaturated surfactant (sodium dodecyl sulfate: NaDS) decreased with increasing NaDS concentrations until reaching the critical micelle concentration of the surfactant mixture. These results show that the second suractant can act as a wetting agent in this saturated surfactant system. Application of Young’s equation to contact angles showed that the solid/liquid surface tension can change substantially with surfactant concentration and be important in addition to the liquid/vapor surface tension in reducing contact angles. Application of the Zisman equation results in a “critical” surface tension for the CaC₁₂ or soap scum of 25.5 mN/m, which is comparable to difluoroethene.     

Chemical structure/property relationships in surfactants. 17. N-substituted-N-acyl glycinates in pure and synthetic hard river water

The surface properties [effectiveness of surface tension reduction (γ_CMC), critical micelle concentration (CMC), efficiency of surface tension reduction (pC ₂₀), maximum surface excess concentration (Γ_CMC), minimum area/molecule at the interface (A _min), and the CMC/C ₂₀) ratio] of well-purified N-substituted glycine derivatives, having the structural formula RC(O)N(R′)CH₂COONa, where RC(O)=lauroyl, myristoyl, or oleoyl, and R′=Et, Pr, Bu, CH₂CH₂OH or CH₂CH₂CH₂OCH₃, were investigated at 25°C in hard river water and distilled water. These surfactants show greater surface activity in hard river water than in distilled water. The effect of both the main alkyl chain R and the N-substituent R′ on surface properties was elucidated, the oleoyl group showing properties equivalent to that of a C₁₆ saturated acyl group. A linear relationship was observed between the pC ₂₀ or CMC values and the number of carbon atoms in the alkyl chain R or in R′ when it was alkyl. With increase in the number of carbon atoms in either R or the N-substituent R′ when it is alkyl, both pC ₂₀ and micelle-forming ability increase, although the effect of R′ on the foregoing two surface properties is lower than that of R. When R′ is (CH₂)₃OCH₃, however, the results suggest that R′ is only partly removed from contact with the aqueous phase either upon adsorption at the water/air interface or upon micellization. It increases A _min, is equivalent only to an ethyl group in its effect on pC ₂₀ and to a methyl group in its effect on CMC, and, in contrast to the effect of R′ when it is alkyl, produces no increase in the CMC/C ₂₀ ratio. As a result, γ_CMC increases with R when R′ is alkyl and decreases with R when R′ is (CH₂)₃OCH₃.     

Chemical fixation of carbon dioxide to dimethyl carbonate from propylene carbonate and methanol using ionic liquid catalysts

The synthesis of dimethyl carbonate (DMC) through the transesterification of propylene carbonate (PC) with methanol was investigated by using imidazolium salt ionic liquid catalysts. 1-alkyl-3-methyl imidazolium salts of different alkyl group (C₂, C₄, C₆, C₈) and anions (Cl⁻, Br⁻, BF₄⁻, PF₆⁻) were used for catalysts. The reaction was carried out in an autoclave at 140–180°C under carbon dioxide pressure of 1.48–5.61 MPa. The imidazolium salts of shorter alkyl group, and more nucleophilic counter anion exhibited higher catalytic activity. The conversion of PC increased as CO₂ pressure and reaction temperature increased. Kinetic studies were also performed to better understand the reaction mechanism. This paper was presented at the 6 ^th Korea-China Workshop on Clean Energy Technology held at Busan, Korea, July 4–7, 2006.     

Biocidal polymers active by contact. II. Biological evaluation of polyurethane coatings with pendant quaternary ammonium salts

Films of polyurethane were prepared by reaction of hydroxytelechelic polybutadienes carrying covalently bound quaternary ammonium salts with an aliphatic triisocyanate. These coatings exhibited high biocidal activity against Gram-positive and Gram-negative bacteria, yeasts, and moulds. It was found that many parameters controlled the bioactivity such as the time of contact between films and bacteria, the [NCO]/[OH] ratio used to prepare the cured polyurethane, the concentration of quaternary ammonium salts in the coating, and the length of the alkyl chain from C₈ to C₁₆ linked to the quaternary nitrogen atom. A secondary phenomenon of diffusion only observed with the shorter alkyl chains (C₈ and C₁₀) was shown to be due to synthesis residues. After these water-soluble impurities are eliminated, the biocidal activity remains excellent: then it is due only to a contact polymer bacteria. © 1993 John Wiley & Sons, Inc.     

Highly electrophilic metallocenes and their role in alkene polymerizations

This summary explores three main topics: (1) zwitterionic alternatives to cationic metallocene alkyl complexes as olefin polymerization catalysts, based on borato (–BR ₃ ^- ) and boryl (–BR₂) substituted cyclopentadienyl ligands (R = C₆F₅); including zwitterionic zirconium allyl complexes of the type CpZr(η³-allyl){η³-allyl–CH₂B(C₆F₅)₃}; (2) reactions which contribute to catalyst deactivation, notably aluminum alkyl mediated C₆F₅ transfer reactions as well as C–H activation reactions including an unusual case of catalyst self-reactivation; (3) the role of highly electrophilic metallocene complexes of aluminum, zirconium and yttrium in combination with weakly coordinating anions as initiators for the carbocationic polymerization of isobutene and isobutene–isoprene copolymerizations is discussed. This revised version was published online in June 2006 with corrections to the Cover Date.     

Soap-based detergent formulations: XXIII. Synthesis of p-sulfobenzyl ammonium inner salts and structural correlation with analogous amphoterics

Two series of p-sulfobenzyl ammonium inner salts, RN⁺(CH₃)₂CH₂C₆H₄SO₃⁻ and RCONH(CH₂)₃N⁺−(CH₃)₂CH₂C₆H₄SO₃⁻, where R is a straight chain alkyl group, were prepared by sulfonation of the corresponding quaternary ammonium chlorides. Although both series have excellent lime soap dispersion properties, the former series gave optimum detergency at considerably shorter alkyl chain length than the latter serires. The detergency, lime soap dispersion ability, and solubility of these compounds were compared with those of structurally analogous aliphatic sulfobetaines. Structural variations, such as length and nature of the bridge between the cationic and anionic groups, length of the lipophilic chain, and insertion of an amidopropyl group into the lipophilic portion of the molecule, significantly altered the detergency and solubility but not the lime soap dispersing ability of the amphoterics.     

Aggregation Behavior of Surface Active Dialkylimidazolium Ionic Liquids [C12C n im]Br (n = 1–4) in Aqueous Solutions

Four diakylimidazolium ionic liquids, namely 1-alkyl-3-dodecylimidazolium bromides ([C₁₂C _n im]Br) with the same dodecyl long-chain tail (C₁₂) and the short alkyl side chain (C _n , n = 1–4), were synthesized, and their molecule structures were confirmed by ESI–MS, ¹H-NMR and elemental analysis. The physicochemical properties of [C₁₂C _n im]Br (n = 1–4) were determined by means of surface tension and fluorescence probe methods, respectively. It was found that elongation of the side chain length will bring about an enhancement of surface activity. Along with the side chain length increasing, the critical micelle concentration (CMC), surface tension at CMC (γ _CMC), the maximum surface excess (Γ_m), micellar aggregation number (N _m) and micellar microenvironment polarity of [C₁₂C _n im]Br decrease, while adsorption efficiency (pC ₂₀), surface pressure at CMC (Π_CMC), the minimum molecular cross-sectional area (A _min) at air-solution interfaces and CMC/C ₂₀ ratio increase.     

Cycloaddition of carbon dioxide to epichlorohydrin using ionic liquid as a catalyst

The cycloaddition of carbon dioxide to epichlorohydrin was performed without any solvent in the presence of ionic liquid as catalyst. 1-Alkyl-3-methyl imidazolium salts of different alkyl group (C₂, C₄, C₆, C₈) and anions (Cl⁻, BF₄⁻, Br⁻, PF₆⁻) were used for this reaction carried out in a batch autoclave reactor. The conversion of epichlorohydrin was affected by the structure of the imidazolium salt ionic liquid; the one with the cation of longer alkyl chain length and with more nucleophilic anion showed better reactivity. The conversion of epichlorohydrin increased as the temperature increased from 60°C to 140°C. It also increased with increasing carbon dioxide pressure probably due to the increase of the absorption of carbon dioxide into the mixture of epichlorohydrin and the ionic liquid. Zinc bromide was also tested for its use as a cocatalyst in this reaction. This work was presented at the 6 ^th Korea-China Workshop on Clean Energy Technology held at Busan, Korea, July 4–7, 2006.     

Gas chromatographic analysis for alpha-olefin sulfonate

The separation and determination of alkene sulfonate and hydroxyalkane sulfonate, and the carbon chain distribution of the lipophilic groups of long chain alpha-olefin sulfonates (C₁₄ to C₁₈) were studied by means of gas chromatography. Samples were hydrogenated initially, and converted to sulfonyl chlorides for gas chromatographic analysis. Using a glass column, 4 mm i.d. and 2.5 m long, packed with Silicon SE-30, 3% on 60 to 80 mesh Chromosorb WAW treated with hexamethyldisilazane, a 0.3 to 0.6 μl sample, as 10% carbon tetrachloride solution, was injected directly on the column, and alkane and monochloroalkane sulfonyl chloride were determined as alkyl chloride and alkyl dichloride, respectively. Minimization of further decomposition, improvement of peak separation and reproducibility were accomplished by this procedure. The method was applied to alpha-olefin sulfonates produced commercially from C₁₄ to C₁₈ alpha-olefins.     

Synthesis and Properties of Dissymmetric Gemini Surfactants

A series of novel dissymmetric gemini surfactants, [C _m H_2m+1COOC₂H₄(CH₃)₂N(CH₂)₃N(CH₃)₂C₂H₄OOCC _n H_2n+1]Br₂ was synthesized and symbolized as m-s–n. The Krafft temperatures and surface tension curves of the dissymmetric gemini surfactants were measured using an electrical conductivity method and a drop volume method. The low Krafft temperatures indicate very good solubility of these esterquat gemini surfactants. With the increasing numbers of carbon atoms in the hydrophobic alkyl chain, the critical micelle concentration (CMC) and the minimum surface area (A _min) decrease, and the efficiency of surface tension reduction (pc₂₀) increases. With the same numbers of carbon atoms in the hydrophobic alkyl chain, the dissymmetric gemini surfactant has a lower CMC and a smaller A _min than the corresponding symmetric gemini surfactant due to the enhanced hydrophobic interactions.     

Higher aluminum trialkyls and magnesium aluminum alkyls as components of zioegler–natta catalysts

Magnesium aluminum alkyls containing higher (C₄–C₁₀) radical swere studied as components of Ziegler–Natta catalysts in styrene polymerization. The effects of alkyl radical length and MgR² contents in the components mentioned on the degree of TiCl₄ reduction and sterospecific activity of the catalysts were investigated. The components studied exdhibited high reducing (for TiCl4) and catalytic a tivities. Moleculear weight of the synthesized isotactic polystyrene was abnormally high.     

Alkyl glycerol monoethers in the marine spongeDesmapsamma anchorata

1-O-Hexadecylglycerol (chimyl alcohol), 1-O-heptadecylglycerol and 1-O-octadecylglycerol (batyl alcohol) have been identified as the major native constituents of a mixture of free alkyl glycerol ethers isolated from the contained water and the methanolic extract of the spongeDesmapsamma anchorata. Minor components were the free C₁₄, C₁₅, C₁₉, C₂₀ and C₂₁ alkyl glycerol monoethers. The alkyl glycerol monoethers were analyzed and identified by gas chromatography/mass spectrometry of their isopropylidene derivatives. This is the first report on the occurrence of free C₁₅, C₁₉, C₂₀ and C₂₁ alkyl glycerol monoethers in a sponge. Contribution No. 1241 from the Instituto de Química, UNAM. This work was presented in part at the First Lanbio Symposium, Trends in Natural Products Research: Prospects for Pharmacological and Agrochemical Applications, Asunción, Paraguay, August 6–10, 1993.