Analysis of chlorinated, sulfochlorinated and sulfonamide derivatives of n-tetradecane by gas chromatography/mass spectrometry

The photosulfochlorination of n-tetradecane by sulfuryl chloride leads to a reaction mixture containing unreacted n-tetradecane, chloro n-tetradecanes and n-tetradecanesulfonyl chlorides. Direct and simultaneousGCanalysis of the mixture of the sulfochlorinated and chlorinated isomers is followed by mass spectrometry identification of all the components either by electron impact (EI-MS) and by negative and positive chemical ionisation (NCI-MS and PCI-MS). With the goal of performing an accurate quantitative GC analysis, and as n-tetradecanesulfonyl chlorides prone to degrade partially into the corresponding chlorides, the former are converted to N,N-diethylsufonamides, more stable thermally, and then analysed by GC/EI-MS and GC/PCI-MS. The chloro n-tetradecanes, sulfonylchlorides and sulfonamides spectra present strong similarities. However, some differences between terminal and internal isomers are noticed and the peculiar behaviour of sulfonamides is emphasized

Optimization of Oil-in-Water Emulsion Stability: Experimental Design, Multiple Light Scattering, and Acoustic Attenuation Spectroscopy

To find an optimal formulation of oil-in-water (O/W) emulsions (o = 0.05), the effect of emulsifier nature and concentration, agitation speed, emulsifying time, storage temperature and their mutual interactions on the properties and behavior of these dispersions is evaluated by means of an experimental design (Nemrodw software). Long-term emulsion stability is monitored by multiple light scattering (Turbiscan ags) and acoustic attenuation spectroscopy (Ultrasizer). After matching surfactant HLB and oil required HLB, a model giving the Sauter diameter as a function of emulsifier concentration, agitation speed and emulsification time is proposed. The highest stability of C12E4-stabilized O/W emulsions is observed with 1% emulsifier

Cloud point extraction of phenol and benzyl alcohol from aqueous stream

Two-aqueous phase extraction of phenol and benzyl alcohol as a solute from their aqueous solutions was investigated using polyethoxylated alcohols (CiEj) as a biodegradable non-ionic surfactant. First, the phase diagrams of the binary systems, water–surfactant (Oxo-C10E3 and Oxo- C13E9), and the pseudo-binary systems, water–surfactant with a constant concentration of solute was determined. The effect of sodium chloride and sodium sulphate on water–surfactant systems were studied. According to the given surfactants concentrations and temperatures, the extraction results were expressed by the following four parameters, percentage of extracted solute, E, which reached 95 and 90% for phenol and benzyl alcohol, respectively, residual concentrations of solute, Xs,w, and the surfactant, Xt,w, in the dilute phase and volume fraction of the coacervate at the equilibrium condition, φc. The values of these parameters were determined by an analyzing central composite designs. After the first extraction process, phenol and benzyl alcohol concentrations in the effluent were reduced about ten times for the first and four times for the second, correspondingly

Phase behavior of pseudoternary brine/alkane/alcohol-secondary alkanesulfonates systems.Surfactant ratio effects of salinity and alcohol

Dodecanesulfonates (isomer mixtures) have been synthesized by the process developed in our laboratory. First, pseudoternary phase diagrams of the water or (brine) decane/ dodecanesulfonates-butan-1-ol systems were drawn and compared with those of a commercial sample (Hostapur 60). In the presence of NaCl, a three-phase region (Winsor III) appears for the two systems, and is larger with the home-made surfactants. This region is interesting in enhanced oil recovery because it leads to very low interfacial tensions. Then, the behavior of the Winsor III region was investigated as a function of the alcohol/surfactant mass ratio (C/T). At a constant salinity (2.5 wt. % NaCl) a value of 2 for C/T gives the best compromise for a larger W III region with both systems. For this ratio, optimal salinity values of 1.55 and 1.65 mass % for our sample and Hostapur 60, were found, respectivel

Microemulsion breakdown by pervaporation technique: Effect of the alkyl chain length of n-alkanol, a cosurfactant of the microemulsion

Two sets of microemulsions, cyclohexane- and water-rich ones, were prepared with the following n-alkanols as cosurfactants: n-propanol, n-butanol, n-pentanol, and n-hexanol. The results showed the influence of the alkyl chain length of the n-alkanol on the permselectivity properties of the pervaporation technique in the breakdown of the microemulsions. The variations of the total flux rate J and the enrichment factor β were in parallel with the effect of the cosurfactant on the swelling extent of the PDMS membrane

Use of inverse gas chromatography to account for the pervaporation performance in the microemulsion breakdown

Mass transfer phenomenon that occurs in the pervaporation process when applied to the microemulsion breakdown, was confirmed by the results of inverse gas chromatography. The stationary phase for this study was polydimethylsiloxane (PDMS), a hydrophobic polymer employed as a membrane in the pervaporation technique. The retention times of the different molecule probes (toluene, cyclohexane, and n-butanol) gave an insight into the extent of the interactions between each of these molecules and the stationary phase; these molecules were the components of the two microemulsions in study. The infinite dilution conditions allowed to determine the thermodynamic and the chromatographic parameters γ∞ (the infinite dilution activity coefficient), the Flory-Huggins parameter interactions χ∞12, and V0g (the specific retention volume), respectively. The magnitudes of the latter parameters threw some light on the permselectivity of the membrane in the pervaporation operation

Investigation of Combined Effects of Xanthan Gum,Sodium Dodecyl Sulphate, and Salt on Some Physicochemical Properties of Their Mixtures Using a Response Surface Method

Aqueous solutions containing sodium dodecyl sulphate, xanthan gum, and salt were characterized by ionic conductivity, viscosity, and surface tension methods. A preliminary experimental study was performed to evaluate the effect of the mixture compositions on the surface behavior of the mixed polymer/surfactant systems under different solution conditions. An experimental design using response surface method (RSM) was then applied to assess factors interactions and empirical models regarding the physicochemical responses variables (i.e., conductivity, surface tension and viscosity). The main effects of the three independent factors: SDS concentration (x1), NaCl concentration (x2) and xanthan concentration (x3) were determined using in particular a D-optimal design. The results show an important effect of the factors on responses; they also indicate that the synergetic action of surfactant, electrolyte and biopolymer greatly influences these properties. Analysis of variance (ANOVA) showed high variance coefficient (R 2 ) values, thus, ensuring a satisfactory adjustment of the second-order regression model with the experimental data

Caractère aromatique et pouvoir donneur d'électrons du dibenzothiophène et de composés apparentés

Dans le cadre de l’étude du comportement des hétérocycles soufres au cours de l'hydrodésulfuration et de leur interaction possible avec le catalyseur on détermine les rotations magnéto-optiques moléculaires par effet Faraday et les anisotropies optiques moléculaires par diffusion Rayleigh dépolarisée, de benzothiophènes. On caractérise également le dibenzothiophène comme donneur d’électrons par l’étude spectrophotométrique de ses complexes en solutio

Determination of micellar system behavior in the presence of salt and water-soluble polymers using the phase diagram technique

The application of micellar systems has been growing during the last years because of their importance in various practical situations. Continued development of their application is necessary. If the principal economic interest of microemulsions is for some time enhanced oil recovery, the following also have significant applications such as pharmaceutical preparations, painting, and products for engine lubrication. The effect of variation in composition of anionic surfactants (α oleifin sulfonates) and the presence of a water-soluble charged polymer (Xanthan gum) and an uncharged polymer [poly (ethylene glycol)] on the phase behaviour of pseudo- ternary systems of water–oil surfactants was investigated. Several domains were observed when the composition of surfactants and cosurfactants (e.g., pentanol) in a mixture is varied. The appearance of these domains in the phase diagram has been attributed to the formation of different Winsor systems

Removal of chromium (III) by two-aqueous phases extraction

Two-aqueous phase extraction of chromium (III) as a solute from their aqueous solutions was investigated using polyethoxylated alcohols (CiEj) as a biodegradable non-ionic surfactant in the presence of anionic sodium dodecylbenzene sulfonate (SDBS). First, the combined effects of chromium and surfactants mixture (anionic and non-ionic) on the cloud point temperature were determined. After this, the phase diagrams of binary systems water–surfactant (NW342 and C10E3) were traced. According to the given surfactants concentration, the extracted solute reached 98.5% and 60% for NW342 and C10E3, respectively at pH equal to 3. The addition of sodium chloride lowers the cloud point temperature of surfactant where the phenomenon of salting-out was pronounced. Under the optimal extraction conditions, the suggested extraction mechanism is based on chromium species-NW342 non-ionic surfactant micelles solvatation. Since, the prevalence species (93.82%) were Cr(III)4(OH)66+, given by a theoretical calculation using CHEAQS V. L20.1. The first stage regeneration of NW342 surfactant was 27.82% at pH equal to 4.23 factorial designs were employed for screening the factors that would influence the overall optimization of a batch procedure of sorption