Striking differences between alkyl sulfate and alkyl sulfonate when mixed with cationic surfactants

The properties of alkyl sulfate and alkyl sulfonate are similar except for their Krafft points. However, alkyl sulfate and alkyl sulfonate behave quite differently when they are mixed with cationic surfactants and show some totally unexpected results. In this work sodium alkyl sulfate (C_nH_2n+1SO₄Na,C_nSO₄)–alkyl quaternary ammonium bromide [C_nH_2n+1N(C_mH_2m+1)₃Br, C_nN, m=1–4] mixtures and sodium alkyl sulfonate (C_nH_2n+1SO₃Na, C_nSO₃)–C_nN mixtures were studied. It was found that, in contrast to the single surfactants, C_nSO₃–C_nN mixtures were much more soluble than C_nSO₄–C_nN mixtures. Besides, the two kinds of catanionic surfactant mixtures were quite different in their phase behavior and aggregate properties. The results were interpreted in terms of the interactions between surfactant molecules, which were very different in the two kinds of mixed systems owing to the distinction between alkyl sulfate and alkyl sulfonate in the molecular charge distribution.     

Tin(IV) complexes ofSchiff bases derived from salicylaldehyde and aminoalcohols

11 and 12 molar reactions of tin(IV) chloride with theSchiff bases, HO–C₆H₄CHNROH [where R=–(CH₂)₂–, –CH₂–, –CH(CH₃)–, –(CH₂)₃–, and –CH(C₂H₅)CH₂–] have been studied in different stoichiometric ratios and derivatives of the type SnCl₄(SBH₂) and SnCl₄(SBH₂)₂ (whereSBH₂ represents theSchiff base molecule) have been isolated. These have been characterised by elemental analysis, conductivity measurements and I.R. spectral studies.     

The effect of electrolyte on the micellar charge and hydration of a polyoxyethylene sulphate type of detergent in aqueous solution

Summary Measurements of the electrophoretic mobilities of the micelles of the anionic detergent C₁₆H₃₃(OCH₂ · CH₂)₇OSO₃Na have been made in aqueous sodium chloride solutions over the concentration range 0-0.01 M and used to calculate the magnitude of the electroviscous effect and the micellar charge in these solutions. The micellar hydration, as assessed from viscosity data, is shown to decrease as the salt concentration is increased and this is thought to be a consequence of the lower micellar charge in the more concentrated salt solutions which allows a greater contraction of the ethylene oxide chains resulting in a loss of water mechanically trapped by the micelles.     

Liquid chromatography with and of platinum complexes

Summary Reversed-phase, high-performance liquid chromatography (HPLC) on chemically bonded C₁₈-phases with acetonitrile-water mobile phases, contianing platinum complexes like Zeise's salt C₂H₄PtCl₃, the amine derivative C₂H₄–PtCl₂–NH₂–CH(CH₃)–C₆H₅ or the amino acid compound C₂H₄–PtCl–OOC–CH(N(CH₃)₂)–C₆H₅ by analogy with argentation chromatography, was used to increase selectivity for the separation of various types of olefins, amines and heterocyclic compounds. On the other hand, normal-phase adsorption chromatography on silica with n-heptane, dichloromethane and n-propanol mobile phases proves to be an ideal tool for the analytical and preparative separation of diastereomeric platinum complexes of olefins, introduced by Gil-Av, that can be easily preparedin vitro, by the reaction of C₂H₄–PtCl–OOC–CH(N(CH₃)₂)–C₆H₅ with optically active olefins in CH₂Cl₂. The preparation of the intitial complex as well as its application to the separation of several interesting types of enantiomeric olefins is described and discussed. The number and amount of separable diastereomers formed by the above reaction is strongly influenced by sterical effects. By comparison of the chromatographic pattern of either racemic or partly racemic mixtures, it is possible to decide, which peaks belong to one or the other enantiomeric form of the olefin.     

Excess Volumetric and Spectroscopic Properties of Mixtures of Some <Emphasis Type="Italic">n</Emphasis>-Alkoxyethanols and of Some Polyethers with 2-Pyrrolidinone and <Emphasis Type="Italic">N</Emphasis>-Methyl-2-Pyrrolidinone at 298.15 K

Excess molar volumes V_m^E for binary liquid mixtures of n-alkoxyethanols or polyethers + 2-pyrrolidinone or N-methyl-2-pyrrolidinone have been measured with a continuous dilution dilatometer at 298.15 K and atmospheric pressure as a function of composition. The alkoxyethanols are diethylene glycol monomethylether, 2-(2-methoxyethoxy) ethanol, CH₃(OC₂H₄)₂OH; diethylene glycol monoethylether, 2-(2-ethoxyethoxy) ethanol, C₂H₅(OC₂H₄)₂OH; and diethylene glycol monobutylether, 2-(2-butoxyethoxy) ethanol, C₄H₉(OC₂H₄)₂OH; whereas the polyethers are diethylene glycol dimethylether, bis(2-methoxyethyl)ether, CH₃(OC₂H₄)₂OCH₃; diethylene glycol diethylether, bis(2-ethoxyethyl)ether, C₂H₅(OC₂H₄)₂OC₂H₅; and diethylene glycol dibutylether, bis(2-butoxyethyl)ether, C₄H₉(OC₂H₄)₂OC₄H₉. In all mixtures the excess molar volumes are negative and symmetric across the entire composition range. The excess volumes are fitted to the Redlich–Kister polynomial equation to obtain the binary coefficients and the standard errors. The experimental results have also been discussed on the basis of IR measurements.     

Cyclopentadienyl-Liganden mit hydrophilen tentakeln

Cyclopentadienyl ligands bearing hydrophilic tentacles are obtained by treating Cp′SiMe₂Cl (Cp′ Cp or C₅Me₄H) with H(OCH₂CH₂)_nOMe (n = 2 or 3) in the presence of pyridine; the products Cp′SiMe₂(OCH₂CH₂)_nOMe can be deprotonated by potassium in toluene. Reaction of the potassium salt of CpSiMe₂(OCH₂CH₂)₂OMe with Me₂SiCl₂ yields C₅H₄(SiMe₂Cl)(OCH₂CH₂)₂OMe, which can be treated with H(OCH₂CH₂)₂OMe to give C₅H₄[(OCH₂CH₂)₂OMe]₂.     

Investigation of conjugation in the Si-O-C-C-N system by nuclear magnetic resonance

The proton-magnetic-resonance spectra were investigated for 19 -aminoethoxysilanes in the R_4-nSi(OCH₂CH₂NR₂)_n and R_3-m(CH₂CH₂OR)_m series, where R=CH₃, C₂H₅, or C₆H₅; R=H, CH₃, C₂H₅, or Si(CH₃)₃; and the values of n and m are 1–4 and 1–3, respectively. In the Si-O-C-C-N system the effect of substituents at the nitrogen or silicon atoms is transmitted either by conjugation in the chain or, when the conjugation is broken, by an induction mechanism.     

Cationic and Anionic Effects on the Glass Transition Temperature for Aqueous Electrolyte Solutions

Glass-forming composition regions of aqueous CH₃COOM (M = Li, Na, K, Rb, Cs, and Tl), CF₃COOM (M = Li, Na, K, Rb, and Cs), and Et₄NX (Et₄ = C₂H₅, X = OH, CH₃COO, Cl, Br, NO₃, and SCN) solutions are reported as a function of water concentration R (R = moles of water per moles of salt). Glass transition temperatures (T _g) were measured by a simple differential thermal analysis (DTA) method with a cooling rate of about 600 K-min^–1. The T _g of all solutions decrease with increasing R (decreasing salt concentration). It is found that T _g at the same R value decrease in the order Na⁺ > Li⁺ > K⁺ > Rb⁺ > Cs⁺ in all glass-forming composition regions of the alkali acetate salt and alkali trifluoroacetate salt solutions. T _g for Et₄NX solutions decrease in the order CH₃COO^– ~OH^– > Cl^– > Br^– > NO ₃ ^– > SCN^–. The effects of the cation and anion on the glass-forming behavior in these aqueous solutions are discussed.     

Chemistry of oxovanadium(IV) bound to tetradentate ONNO donors: Influence of axial coordination on the V-O(1)bond

Chelating behaviour of some tetradenate ONNO donors derived fromq - aminobenzoylhydrazide and some diketones toward oxo-vanadium(IV) ion is reported. The donors react with oxometal cation depending on the pH of the reaction medium. The product containing the neutral keto and the binegative enol form of the donors have the formulae [VO(H₂L)(SO₄)] (at pH 3.0)(┘1) and [VO(L)(H₂O)] (at pH 6.0)(┘2) respectively [H₂L = (2-NH₂)C₆H₄CONH: C(R) (CH₂)_mC(R): NNH CO C₆H₄(2−NH₂); H₂L = H₂DA(R= CH₃,m = 0), H₂BA(R = C₆H₅,m = 0), H₂AA(R = CH₃,m = 2)]. Both (┘1) and (┘2) react with a neutral monodentate donor B(B = pyridine, aniline etc.) yielding mixed-ligand complexes [VO(L)(B)]. Influence of the axial coordination on the V-O₍₁₎ bond is discussed and a monomeric distorted octahedral donor environment for the oxovanadium(IV) ion has been suggested     

Cyclopalladation of mono-, di- and tribenzylamine by palladium(II) acetate: Influence of bulkiness around the nitrogen atom of benzylamine upon internal metallation

Cyclopalladation of mono-, di- and tribenzylamine has been investigated by reacting the corresponding amines with an equimolar amount of palladium(II) acetate (reaction i), or by heating the corresponding bis-amine complexes [Pd(O₂CMe)₂{(PhCH₂)_nNH_3−n}₂] (n=1, 2) (reaction ii). By the reaction i, all the three amines undergo cyclopalladation. However, in the case of the reaction ii, only the dibenzylamine complex [Pd(O₂CMe)₂{(PhCH₂)₂NH}₂] has been converted into a cyclopalladated complex. The reactivity of the three benzylamines towards cyclopalladation has been discussed in terms of the co-ordinating ability influenced by the bulkiness around the nitrogen atom. Temperature-dependent ¹H-NMR spectra are observed for mononuclear cyclopalladated complexes [Pd(O₂CMe){C₆H₄CH₂N(CH₂Ph)₂–C¹, N}L] (L=PPh₃, AsPh₃) and are attributed to the dissociation of the nitrogen atom in the cyclopalladated chelate ring. A heteroleptic bis-cyclopalladated complex [Pd[C₆H₄CH₂N(CH₂Ph)₂–C¹, N](C₆H₄CH₂NMe₂–C¹, N)] has also been prepared. X-ray crystallographic studies on [{Pd(O₂CMe)[C₆H₄CH₂N(CH₂Ph)₂–C¹, N]}₂] and [Pd[C₆H₄CH₂N(CH₂Ph)₂–C¹, N](C₆H₄CH₂NMe₂–C¹, N)] have been reported.     

Synthesis,spectroscopic and X‐ray single‐crystal structure study of bis(2‐methoxy‐ethanolato)‐bis(8‐quinolinato)titanium(IV)

Reaction of Ti(OCH₂CH₂OR)₄ (R?CH₃ and C₂H₅) with 8‐hydroxyquinoline in benzene at room temperature resulted in the formation of Ti(C₉H₆NO)₂(OCH₂CH₂OR)₂, characterized by IR, ¹H‐NMR, UV and mass spectroscopies. The molecular structure of Ti(C₉H₆NO)₂(OCH₂CH₂OCH₃)₂ has been determined by single‐crystal X‐ray structure analysis. The geometry at titanium is a distorted octahedron, with the nitrogen atoms of quinolinate occupying the trans position with respect to oxygens of the 2‐methoxyethoxy groups. The prepared quinolinate derivatives of titanium alkoxides are very stable towards hydrolysis and harsh conditions are required for hydrolytic cleavage. Copyright © 2005 John Wiley & Sons, Ltd.     

The effect of electrolyte on the micellar properties of an anionic-nonionic detergent in aqueous solution

Summary The effect of sodium chloride on the micellar properties of an anionic-nonionic detergent C₁₆H₃₃(OCH₂·CH₂)₇OSO₃Na has been investigated and the results have been compared with previous measurements on the nonionic analogue C₁₆H₃₃(OCH₂·CH₂)₇OH. Light scattering and viscosity measurements showed that, over the electrolyte concentration range studied (0–1.0M NaCl), the micelles were very much smaller (m.m.w.=74,800 in 0.1M NaCl) than those of the nonionie analogue and exhibited no similar variation of size, shape or hydration with temperature, indicating that addition of electrolyte caused insufficient shielding of the micellar charge to induce nonionic behaviour. Viscosity results suggested a reduction in the micellar hydration with increase in electrolyte concentration to a limiting value of 0.28 g H₂O/g of detergent for salt concentrations greater than 0.01M. A possible explanation of this effect is proposed. The effect of electrolyte on the c.m.c. was determined from surface tension measurements and was described by the equation, log c.m.c.=−6.4−0.54 log (c.m.c.+salt conc.) Comparison with data reported for sodium hexadecylpolyoxyethylene sulphates with shorter ethylene oxide chain lengths indicated a decrease in the c.m.c. in salt-free systems with increase in the chain length, the data obeying the equation, log c.m.c.=−3.5−0.20n wheren is the number of ethylene oxide groups in the chain.     

The physicochemical properties of aqueous mixtures of cationic-anionic surfactants: I. The effect of chain length symmetry

The solution behaviors of equimolar mixtures of cationic-anionic surfactants have been studied by means of the dynamic light scattering technique and surface tension measurements. The surface activity and the micellization properties are different for systems of different hydrophobic chain length symmetry. For systems of lower symmetry (e.g., C₆H₁₃NC₅H₅Br-C₁₂H₂₅SO₄Na mixture), the surface tension at cmc (γ_cmc) is rather high (above 30 mN m⁻¹) and the mixtures form genuinely homogeneous micellar solutions above the cmc. For the systems of high symmetry (e.g., C₈H₁₇NC₅H₅Br-C₈H₁₇SO₄Na mixture), γ_cmc is very low (about 24 mN m⁻¹, near the value of pure hydrocarbon) and in the apparently homogeneous and clear mixtures slightly above cmc, the aggregates grow slowly and eventually form small droplets; as the concentration is further increased, all these solutions become turbid. We have proposed a new concept of conformation energy of aggregates to account for all these phenomena. Mixtures of octyltriethylammonium bromide and sodium octylsulfate form clear homogeneous micellar solutions in keeping with predictions based upon this concept.     

Preparation and Electrical Properties of Lnx(SiO4)6O(1.5x?12) (Ln: Nd, La) with Apatite Structure

In this study, Ln_x(SiO₄)₆O_(1.5x–12) (Ln: Nd, La) materials as electrolytes for solid oxide fuel cells (SOFC) were prepared by the sol-gel process. It has been reported that the apatite structure of Ln_x(SiO₄)₆O_(1.5x–12) shows higher ionic conductivity than yttrium-stabilized zirconium oxide at the working temperature of the SOFC. Ln₁₀(SiO₄)₆O₃ is a major component of the Ln_x(SiO₄)₆O_(1.5x–12) system. Ln₁₀(SiO₄)₆O₃ consists of Ln_9.33(SiO₄)₆O₂ and a small amount of Ln₂SiO₅. It has been proposed that the ionic conductivity of Ln_x(SiO₄)₆O_(1.5x–12) decreases with increasing Ln₂SiO₅ with non-apatite structure. The object of the present study was to bring about this decrease by generating Ln₂SiO₅ in the system.Precursor solutions for synthesis of the powder were prepared using tetraethoxysilane (Si(OC₂H₅)₄) and neodymium acetate monohydrate (Nd(CH₃COO)₃·H₂O) or lanthanum acetate monohydrate (La (CH₃COO)₃·H₂O) as raw materials and acetic acid (CH₃COOH), 2-methoxyethanol (C₂H₅OCH₂CH₂OH), and triethanolamine (N(CH₂CH₂OH)₃) as solvents. To obtain the powder, the solution was dried and heat-treated at 600 °C for 2 h. Disks made from the powder were heat-treated at temperatures between 1100 and 1500 °C for 10 h. The results of an XRD investigation indicate that almost all diffraction peaks of these samples could be assigned to Ln_9.33(SiO₄)₆O₂. The sample with x = 10.00 included a small amount of Ln₂SiO₅. The ionic conductivity of this latter sample was higher than that of other samples with similar values of x (x = 9.33 and 10.67).     

Mixed Complex Salt [Cu4(SCN2H4)7(NO3)](NO3)(SO4) · 3.3H2O: Synthesis and X-Ray Diffraction Analysis

The complex salt [Cu₄(SCN₂H₄)₇(NO₃)](NO₃)(SO₄) · 3.3H₂O was synthesized via reaction of aqueous solutions of thiourea with copper nitrate at 80°C and studied using X-ray diffraction analysis. The conditions and reasons for the partial oxidation of thiourea to sulfate ions were established. The crystals are monoclinic: a = 12.6072(7) Å, b = 15.4265(8) Å, c = 22.108(1) Å, = 120.133(6)°, space group P2₁/c, Z = 4. The crystal structure consists of [Cu₄(SCN₂H₄)₇(NO₃)]³⁺ complex cations, SO₄ ^2–, and NO₃ ^– anions, and molecules of the water of crystallization. Three types of coordination of the Cu atom were distinguished in the structure: trigonal (Cu–S 2.213–2.279 Å), tetrahedral (Cu–S 2.315–2.459 Å), and trigonal–pyramidal (3+1) (Cu–S 2.26–2.288, Cu–O 2.68 Å). The NO₃ ligand was found to be orientationally disordered.     

Structure and Magnetic Characteristics of New Binuclear Complexes Based on Bisbenzoylhydrazones of 2,6-Diformyl-4-R-phenols and Copper(II) Nitrate

A series of binuclear Cu(II) complexes with bisbenzoylhydrazones of 2,6-diformyl-4-R-phenols (R = OCH₃, CH₃, CH₂Ph, Cl, Br, CO₂CH₃) with H₂LCu₂(NO₃)₂(OCH₃) composition, where H₂L^–are monodeprotonated bishydrazones, was synthesized. The structure of the obtained complexes was established using IR spectro-scopy and conductometric and magnetochemical data. The title complexes were shown to exhibit exchange interaction of the antiferromagnetic type. Results of quantum-chemical calculations of structures modeling the state of a ligand in the complex were used to discuss the effect of substituent R nature on magnetic exchange in the complexes.     

SANS study of alkyl polyoxyethylene sulfate micelles. Sodium dodecyl(oxyethylene)4sulfate in D2O at 25°C

n-C ₁₂ H ₂₅ (OC ₂ H ₄ ) ₄ SO ₄ Na micelles have been investigated by small angle neutron scattering technique. Results have been obtained for a series of solutions of variable concentration of surfactant and for an approximately 0.07M solution to which different amounts of NaCl were added. Micellar parameters, aggregation number, and apparent charge have been compared to those previously obtained for C ₁₂ H ₂₅ (OC ₂ H ₄ ) ₄ SO ₄ Na. On changing the surfactant concentration, the growth gradient of micelles of the latter is similar to the growth gradient of micelles of C ₁₂ H ₂₅ (OC ₂ H ₄ ) ₄ SO ₄ Na when no excess salt is present. In the presence of added electrolyte, C ₁₂ H ₂₅ (OC ₂ H ₄ ) ₂ SO ₄ has a higher growth gradient than C ₁₂ H ₂₅ (OC ₂ H ₄ ) ₄ SO ₄ . This result has been interpreted in terms of effect of the oxyethylene group. The monodisperse core+shell spherical model of micellar structure previously proposed for this class of surfactant seems to hold in a wide range of concentrations of surfactant and/or added electrolyte.     

Magnetische Untersuchungen an Komplexen von La(III), Pr(III) und Nd(III) mitSchiffschen Basen

Specific magnetic susceptibilities (_s) of several newly synthesized chelates of some of the lanthanons [La(III), Pr(III) and Nd(III)] are reported. These derivatives are of the general type,Ln(O-i-C₃H₇)_3–n (C₆H₅CHNRO) _n [where,Ln=La(III), Pr(III) or Nd(III);n=1 or 2 and R=CH₂CH₂, CH₂CHCH₃ or C₆H₄] and have been prepared by the reaction of the alkoxides of the lanthanons withSchiff bases such as benzylidene-2-hydroxyethylamine (C₆H₅CHNCH₂CH₂OH), benzylidene-2-hydroxy-n-propylamine (C₆H₅CHNCH₂CHOHCH₃) and benzylidene-o-aminophenol (C₆H₅CHNC₆H₄OH) in different molar relations in dry benzene.The resulting crystalline derivatives are non-volatile, light to deep yellow or blackish in colour. These tend to polymerize on keeping as shown by their insoluble nature and higher melting points, the polymerisation possibly occurring by the intermolecular coordination through oxygen atoms as reported earlier¹.UsingGouy method², the bis-isopropoxy mono-Schiff base and mono-isopropoxy bis-Schiff base complexes of La(III) have been shown to be diamagnetic, with _s values being in the range of –0.32 to –0.45×10^–6 and –0.39 to –0.55×10^–6 c.g.s. units at 305 K respectively.In the remaining derivatives, Pr(O-i-C₃H₇)_3–n (C₆H₅CH NRO) _n and Nd(O-i-C₃H₇)_3–n (C₆H₅CHNRO) _n (where,n=1 or 2 and R=CH₂CH₂, CH₂CHCH₃ or C₆H₄) the magnetic moment values range between 3.25 to 3.32 and 3.30 to 3.33 _B respectively indicating their paramagnetic nature.     

Complexes of apatitic layered compound Ca8(HPO4)2(PO4)4·5H2O with dicarboxylates

Octacalcium phosphate(OCP), Ca₈(HPO₄)₂(PO₄)₄·5H₂O, consists of alternative stackings of layers with an apatitic structure and a brushite-like composition. Here we consider whether or not OCP is able to complex with organic substances. The interplanar spacing (d₁₀₀) of OCP prepared in the presence of dicarboxylates (RC₂O₄ ^2–; R=organic group) expanded from the original value of 18.7 Å to 19.2–26.1 Å depending on the length of R. Examples of R were C_nH_2n(n=1–6), CH(CH₃)CH₂, C(CH₃)=CH, CH=CH, CH₂CH=CHCH₂ and C₆H₄. Structural considerations and experimental data suggested that dicarboxylates were incorporated into the OCP structure through the replacement of HPO₄ ^2– by RC₂O₄ ^2–.     

Interaction of polyoxyethylene cholesteryl ethers with liposomal membranes

In order to deduce the mechanisms of hemolysis induced with the nonionic surfactants, polyoxyethylene cholesteryl ethers, C₂₇H₄₅(OCH₂CH₂) _n OH (n=8, 25, 30, 50) and polyoxyethylene dihydrocholesteryl ethers, C₂₇H₄₇(OCH₂CH₂) _n OH (n=15, 30, 50), the interaction of these surfactants with the liposomal membrane as a simple model membrane was investigated in terms of a leakage of the entrapped marker, and a change of the membrane fluidity. The time-courses of the marker leakage were characterized with two kinetic parameters, the initial induction period and the apparent first-order rate constant. The polyoxyethylene chain length was an important factor in the membrane-lytic activities, and the maximal rate as well as the maximal amount of the marker leakage was observed with n=25–30 in these surfactants series. However, the apparent activation energies derived from the two kinetic parameters increased almost linearly with the hydrophilic chain length. The used surfactants tended to fluidize the liposomal membrane in the concentration ranges of surfactants where the marker leakage is not at all or only slightly induced — but with the higher concentration of the cholesteryl derivatives, the apparent fluidity was significantly reduced. From these observations, the mechanisms of the membrane-lysis are discussed.