Anionic Tensides Research Articles

Reactivity Tracers of the Hydrolysis of Fe(II)‐Bis(salicylidene) Complexes: Initial–Transition States Analysis and Enhanced Impact of Tensides on the Kinetic Trends

ABSTRACTThe kinetics of the acid hydrolysis reaction of Fe(II)‐bis(salicylidene) complexes were followed under pseudo–first‐order conditions ([H+] >> [complex]) at 298 K. The ligands of the studied azomethine complexes were derived from the condensation of salicylaldehyde with different five α‐amino acids. The hydrolysis reactions were studied in acidic medium at different ratios (v/v) of aqua–organic mixtures. The decrease in the dielectric constant values of the reaction mixture enhances the reactivity of the reaction. The transfer chemical potentials of the initial and transition states (IS–TS) from water into mixed solvents were determined from the solubility measurements combined with the kinetic data. Nonlinear plots of logkobs versus 1/D (the reciprocal of the dielectric constant) suggest the influence of the solvation of IS–TS on the reaction reactivity. Furthermore, the acid hydrolysis reactions were screened in the presence of different concentrations of cationic and anionic tensides. The addition of surfactants to the reaction mixture accelerates the reaction reactivity. The obtained kinetic data were used to determine the values of δmΔG# (the change in the activation barrier) for the studied complexes when transferred from “water to various ratios (v/v) of water–co‐organic binary mixtures” and from “water to water containing different [surfactant].” It was found that the reactivity of the acid hydrolysis reaction was controlled by the hydrophobicity of the studied chelates.

Surfactants, not size or zeta-potential influence blood–brain barrier passage of polymeric nanoparticles

Nanoparticles (NP) can deliver drugs across the blood–brain barrier (BBB), but little is known which of the factors surfactant, size and zeta-potential are essential for allowing BBB passage. To this end we designed purpose-built fluorescent polybutylcyanoacrylate (PBCA) NP and imaged the NP’s passage over the blood-retina barrier – which is a model of the BBB – in live animals.Rats received intravenous injections of fluorescent PBCA-NP fabricated by mini-emulsion polymerisation to obtain various NP’s compositions that varied in surfactants (non-ionic, anionic, cationic), size (67–464nm) and zeta-potential. Real-time imaging of retinal blood vessels and retinal tissue was carried out with in vivo confocal neuroimaging (ICON) before, during and after NP’s injection.Successful BBB passage with subsequent cellular labelling was achieved if NP were fabricated with non-ionic surfactants or cationic stabilizers but not when anionic compounds were added. NP’s size and charge had no influence on BBB passage and cell labelling. This transport was not caused by an unspecific opening of the BBB because control experiments with injections of unlabelled NP and fluorescent dye (to test a “door-opener” effect) did not lead to parenchymal labelling.Thus, neither NP’s size nor chemo-electric charge, but particle surface is the key factor determining BBB passage. This result has important implications for NP engineering in medicine: depending on the surfactant, NP can serve one of two opposite functions: while non-ionic tensides enhance brain up-take, addition of anionic tensides prevents it. NP can now be designed to specifically enhance drug delivery to the brain or, alternatively, to prevent brain penetration so to reduce unwanted psychoactive effects of drugs or prevent environmental nanoparticles from entering tissue of the central nervous system.

Treatment of wastewater in hybrid constructed wetland from the production of vinegar and packaging of detergents

The results are presented of a 2-year monitoring of the performance of a hybrid constructed wetland (CW), which was created for the treatment of very heterogeneous industrial wastewater (WW) in Slovenia. WW originated from the food-processing department responsible for the production of wine and apple vinegar and from the chemical department in which the packing of detergents and soaps takes place. The hydraulic variability of theWW was high due to the variable production intensity. Low degradability was found due to the remains of detergents in WW. The average efficiency for COD, BOD5, TOC, total organic N, nitrate-N, phosphate and anionic tensides removal was 67%, 66%, 64%, 83%, 83%, 62% and 67%, respectively. Special attention was given to the anionic tensides. Biodegradability and toxicity tests showed the worst results in samples with the highest concentrations of anionic tensides. During intensive vinegar production, the pH of WW was low. In spite of the compensation lagoon, the neutralisation of pH before the inflow into the CW was not always achieved. This presumably caused leaching of Fe from the substratum in the first beds of the CW and its precipitation into the last bed. The CW proved to have a higher pH buffering capacity compared to the open lagoon. In general, the CW verified the predicted results in the first 2 years of its operation. A further increase in efficiency can be achieved via the separate containment of WW with high concentrations of anionic tensides requiring longer degradation period and via the additional buffering of acid outflow from the vinegar production.

Analysis of tensides in complex samples with comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry

Multidimensional gas-chromatographical analysis of various tensides of natural or synthetic origin in cosmetic products is demonstrated. Comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry allows the qualitative and quantitative determination of alkyl polyglucosides (AG), fatty alcohol ethoxylates (FAEO), fatty alcohol sulfates (FAS), fatty alcohol ether sulfates (FAES) and cocamidopropyl betaines (CAPB) in shower gel and cleaning agents. The samples were aliquoted in two parts. The first part was silylated, diluted and analysed; then, in order to detect anionic tensides (FAES, FAS) too, the second aliquot was hydrolysed before being silylated for analysis. Because of their amphoteric character, the betaines can only be analysed by gas chromatography after thermal decomposition in the injector, which leads to the corresponding amidoamines among other products.

Hydrophobically modified water-soluble polymers and polyelectrolytes as micellar promotors in the Rh(i) catalyzed hydrogenation of an amino acid precursor in water

Hydrophobically modified water-soluble polymers (HMWSP's) and hydrophobically modified polyelectrolytes (HMPE's,“polysoaps”) of various compositions and different molecular weights have been prepared and used in the micellar promoted enantioselective hydrogenation of methyl (Z)-α-acetamidocinnamate with a chiral Rh(I) catalyst in aqueous medium. The efficiency of the micellar polymers in the catalytic reaction is greatly determined by their solubility (dispersibility) behavior and solubilization capacity for catalyst and substrate. The latters depends on the compactness of the polyamphiphiles as revealed by transmission electron microscopy (TEM) and light microscopy images. The highest catalytic performance was obtained with polymer-surfactant complexes prepared by micellar copolymerization with neutral or anionic tensides, regardless of the electrical charge of the hydrophobically modified polymer. In most cases a synergism between rate and enantioselectivity has been observed.

Surfactants with NH 3H 2O

To avoid rivulet flow in compact absorbers, which consist of compact heat exchanger plates, the surface tension of the ammonia-water solution has to be reduced by surfactants. The influence of these additives on the absorption of ammonia into water is investigated for two anionic tensides, two non-ionic tensides and the alcohol 1-octanol in a stagnant pool measuring cell. All four tensides had no influence on the absorption in the concentration range investigated (0.25–0.91 wt%), although they were able to reduce the surface tension of water down to 30mN m −1. In order to increase the mass transfer, 1-octanol was used in three concentrations, which probably lead to a convection in the liquid layer, called Marangoni convection. The experiments have shown that the presence of surfactant islands is not necessary to induce Marangoni turbulence. The best result was achieved with 50 ppm 1-octanol dissolved in water.

Detergent residues in textiles

The purpose of this study was to determine concentrations of detergent residues in textiles washed with three types of detergents. One detergent contained phosphate. In the other two (concentrated or ecological detergents) phosphate had been replaced by zeolite, which contains silicates. The textiles were washed using two programmes for coloured materials (at 60°C). The programmes differed with regard to volume of rinse water and number of rinsings. Detergent residues in textiles were determined chemically. Zeolite particles were determined electron microscopically. The results showed that most of the detergent residues remaining in textile strips were anionic tensides. They increased in proportion to the quantity of detergent used for washing. The least residues were left by concentrated detergents. Anionic tensides are suspected of causing skin irritation, probably allergy in atopic persons. Zeolite particles may irritate skin mechanically or cause through irritation respiratory distress. Washing programmes using less rinse water than other programmes increased detergent residues by 30%. It is concluded that there is a positive linear relationship between concentration of detergent and residues in textiles, and a negative linear relationship between water volume and residues in textiles after laundering. This could be of considerable importance from a health point of view and should be evaluated before any detergent is marketed. A methodology combining different standardized methods for analysing detergent residues in textiles was developed in this study.

New method for detecting rhamnolipids excreted byPseudomonas species during growth on mineral agar

A new semi-quantitative agar plate test for the detection of extracellular rhamnolipids has been developed. These biological anionic tensides (biosurfactants) form an insoluble ion pair with the cationic tenside cetyltrimethylammonium bromide and the basic dye methylene blue which was included in mineral agar plates. On the light blue agar, productive colonies ofPseudomonas spec. were surrounded by dark blue halos. The test is specific for anionic biosurfactants and can be applied to other glycolipid producing microorganims.

ChemInform Abstract: Micelle Activated Reactions. Part 1. Micelle Activated Iodination and Partial Dehalogenation of Pyrazoles and 1,2,4‐Triazoles.

AbstractOnly anionic tensides, e.g. Rodapon N 50, have a catalytic effect on the iodination reactions shown in the scheme.

Über den Einfluss des Akzeptor‐Teilchromophors bei Dimethin‐merocyanin‐Farbstoffen auf das Aggregationsverhalten in wässriger Lösung

On the Influence of the Acceptor Part of the Chromophor of Dimethinemerocyanine Dyes upon the Aggregation Tendency in Aqueous SolutionA series of novel long‐chain alkyl‐dimethinemerocyanine dyes containing sulfonate groups is synthesized in good yield and their aggregation tendency in H2O and in organic solvent/H2O mixtures investigated. The merocyanine dyes 11 and 15 only exhibit an intense, red‐shifted absorption band due to J‐aggregation in H2O without addition of salt. The influence of cationic and anionic tensides and other compounds as urea, glucose, and polysaccharides upon the J‐aggregation tendency is investigated.

ChemInform Abstract: Sulfur Compounds. Part 119. Dissolution of Elemental Sulfur in Water by Means of Cationic and Anionic Tensides.

AbstractIn the presence of neutral tensides as SDS, Tergitol 7, or CTAB the solubility of the hydrophobic α‐S8 in water is enhanced by a factor of at least 5000.

An NMR study of the interaction of phenothiazine derivatives with cationic and anionic tensides

The localization of phenothiazine and its derivative diethazine in the micelles of the cationic tenside Septonex and the anionic tenside sodium dodecyl sulfate in aqueous media was studied by NMR spectroscopy. The changes in the chemical shifts of the individual groups of protons in the tenside molecules indicated that phenothiazine and diethazine are localized near the micelle surface.

Spectrophotometric study of phenothiazine derivatives and their cation radicals in micellar media

The effects of cationic, anionic, and nonionic tensides on the electronic absorption spectra of phenothiazine, diethazine and chlorpromazine and of their cation radicals were studied. The influence of tensides on the cation radical disproportionation in phosphoric acid was also followed. It was found that cationic and nonionic tensides do not affect the disproportionation rate at concentrations below the critical micelle concentration (CMC) but exhibit a catalytic effect if present at concentrations above the CMC. Anionic tensides catalyze the disproportionation if present at subcritical concentrations, but inhibit it at supercritical concentrations. These findings are explained on the basis of solubilization of the cation radicals of the phenothiazine derivatives in micelles and electrostatic interaction of hydrogen ion with the micelles. The importance of the findings for analytical chemistry and pharmacology is discussed.

Comparison of the reactions of ferric ions with Chromazurol S, Eriochromazurol B and Eriochromcyanine R in the presence of surface active substances and spectrophotometric determination of Fe(III)-ions with Chromazurol S-cetylpyridinium bromide system

The spectrophotometric methods of determining Fe(III) ions with Chromazurol S, Eriochromazurol B and Eriochromcyanine R in the presence of cationic, anionic and nonionic tensides were compared using the basic optical and statistical parameters. A method was proposed and developed for the determination of Fe(III) ions using Chromazurol S in blood serum and plasma at pH 4.7-5.0 in a medium of 2 . 10-4M cetylpyridinium bromide and 0.1M pyridine buffer and at pH 6.0-6.5 in a medium of 2 . 10-3M cetylpyridinium bromide and 0.1M hexamethylenetetramine buffer with molar absorption coefficients of 1.31 . 105 and 1.40 . 105, respectively. The determination is sufficiently specific even at pathological concentrations of the other serum components.

Two‐ and Three‐Dimensional Reactions of Ag+2 Radical Cations in Aqueous Solutions of Anionic Tensides

AbstractAg+2 radical cations were produced in aqueous 1 · 10−4 molar Ag2SO4 solutions containing micelles of sodium hexadecyl trioxiethylene sulfate and of sodium dodecylsulfate by a short pulse of high energy electrons. The disappearance of Ag+2 and the appearance of Ag2 were followed by optical measurements in the 10−6 to 10−2 s range. – A fraction of the Ag+2 radicals decayed within 1 to 2 microseconds, and the remaining radicals disappeared in a second order process within 10−4 to 10−2 s. These decay processes are attributed to(a) intramicellar or two‐dimensional radical‐radical reaction at the surface of doubly occupied micelles, and(b) intramicellar or three‐dimensional reaction between radicals that are singly adsorbed at micelles. The fraction of (a) increases with increasing concentration ratio of radicals to micelles as expected from statistical considerations. Deviations at low concentration ratios are attributed to the initial formation of some of the radicals in spurs. The observed 100 fold acceleration of the radical‐radical reaction by the reduction in the dimensionality of reaction space is also compared to similar effects in fast biochemical reactions on large carrier molecules.It is concluded from an analysis of the dependence of the bimolecular rate constant of reaction (b) on the tenside concentration that Ag+2 cations reside longer than milliseconds at micelles and can be exchanged directly between two anionic micelles. The rate constants are given for the two tensides.

The analysis of tensides by automatic radio-frequency titrations

The advantages of radio-frequency end-point detection in titrimetric analysis are discussed, and the design of an automatic titrimeter, equipped with variable frequency and employing the heterodyne-beat principle, is outlined. While determinations of cationic tensides by titrating with anionic ones and vice versa cannot be carried out with sufficient precision, the titration of cationic tensides with silver nitrate, titration of sulphated anionic tensides wth barium acetate or benzidine hydrochloride, and the titration of the alkali metal ion in tensides with ▪ lithium chloride in nonaqueous solution are accurate, precise and simple analytical procedures. Manoxol OT can be employed as a titrant in the determination of alkaloids.