Concentration Of Dodecylbenzenesulfonic Acid Research Articles

Effect of Dodecylbenzenesulfonic Acid as an Asphaltene Dispersant on the W/O Emulsion Stabilized by Asphaltenes and Paraffin Wax

Dodecylbenzenesulfonic acid (DBSA) is injected into wellbores as an asphaltene dispersant to alleviate asphaltene deposition problems. The addition of DBSA will change the dispersion of asphaltenes in the crude oil, affecting the wax precipitation property of the crude oil as well as the adsorption behavior of asphaltenes at the oil–water interface, thus significantly altering the W/O emulsion’s stability. In order to provide better theoretical guidance for oil–water separation in oilfield gathering and production processes, in the paper, the effects of DBSA concentration (from 0 to 500 ppm) on the emulsions’ stability containing both asphaltenes and paraffin wax and the mechanism were systematically investigated at two different temperatures (30 and 15 °C) based on the wax precipitation and rheological properties of the model crude oil, the oil–water interface adsorption properties, and the macroscopic and microscopic properties of the emulsion. The outcomes demonstrated that the test temperature had a highly substantial impact on the model emulsion. The main element affecting the stability of the emulsion at 30 °C (above the wax appearance temperature (WAT)) was the interfacial structure’s strength. The low-temperature flowability of the oil phase primarily controlled the process of emulsion stabilization at 15 °C (below the WAT). Furthermore, we speculate that the wax crystals could precipitate on the surface of the emulsified droplets, which also facilitated emulsion stability at 15 °C. Combining the above experimental observations, the mechanism of DBSA concentration affecting the emulsion stability was proposed, which would contribute to solving the issues in the emulsion breaking and dewatering process of crude oil emulsions.

Effects of dodecyl benzene sulfonic acid between hydrate particles and droplets

In order to understand the effect of Dodecyl benzene sulfonic acid (DBSA) on the aggregation mechanism of hydrate, the interaction between cyclopentane (CyC5) hydrate particles and droplets under different concentrations of DBSA and different temperatures was measured by micro mechanical force device (MMF). The mass concentration range of DBSA used in the experiment is 0.0001% ~ 0.05%, and the experimental temperature is 1°C and 5°C, respectively. The experimental results show that DBSA can effectively reduce the interfacial tension between oil and water, thus reducing the adhesion between hydrate particles and droplets and preventing hydrate aggregation. In the experimental concentration range, the higher the concentration of DBSA, the stronger the ability to reduce the adhesion. The adhesion can be reduced by 97.56% at 1°C and 90.95% at 5°C. The change trend of the adhesion with the concentration is almost the same at the two temperatures.

Theoretical and Kinetic Analysis of the Esterification of Undecylenic Acid with Glycerol.

The synthesis of undecylenic acid partial esters can be performed at mild temperature with a classical esterification reaction catalyzed by dodecylbenzene sulfonic acid (DBSA). A semi-empirical molecular modeling on the different reaction intermediates indicates that DBSA can strongly decrease their heats of formation through hydrogen bonding. Diester formation seems to be thermodynamically favored with a selectivity for alpha, alpha, or alpha, beta forms that depend on the geometry of the catalyst-intermediate configuration. Triesters are not favored but a high selectivity for monoesters requires a kinetic control. Experimental approach, considering different DBSA concentrations and temperature partially confirms the theoretical predictions but surfactant properties of DBSA and monoesters may induce nonpredicted geometries. Global apparent activation energies are calculated, corresponding to the formation and hydrolysis of mono and diesters. If water trapping allows the decrease of hydrolysis reaction constants, the presence of water and subsequent phase separation may explain differences between theoretical and experimental results and could help increasing monoester selectivity.

Electrodeposition of polypyrrole on copper surfaces in OXA-DBSA mix electrolyte and their corrosion behaviour

In this study, polypyrrole (PPy) coatings were formed on the surface of copper electrode via electrochemical polymerization method using different concentrations of monomer, oxalic acid (OXA) and dodecylbenzene sulfonic acid (DBSA) solutions. Prior to the coating process, a pre-passivation process was applied to the copper surface by cylic voltammetry technique in the presence of OXA. The passive copper surface is subsequently coated with PPy films bythe potantiostatic method. Corrosion behavior of uncoated copper and PPy coated copper electrodes after passivation were investigated by potentiodynamic polarization, chronoamperometry and impedance spectroscopy techniques in 0.1 M H2SO4. Characterization studies and surface analyses of the coatings were carried out by using Fourier transform infrared spectroscopy (FT-IR), Thermogravimetry (TG) and Scanning electron microscopy (SEM). The OXA-DBSA mix electrolyte significantly increased the surface homogeneity and adhesion of the coatings leading to a protection efficiency of approximately 100%. While all coatings protected the copper electrodeagainst corrosion, the coating with 0.1 M monomer, 0.1 M OXA and 0.1 M DBSA concentration provided the best protection.

Electrically conductive polyaniline/polyimide microfiber membrane prepared via a combination of solution blowing and subsequent in situ polymerization growth

Dodecylbenzene sulfonic acid (DBSA) doped-polyaniline (PANI) coated conductive polyimide (PI) microfiber membrane was prepared by chemical oxidation polymerization. PI nanofiber membrane was prepared by solution blowing. Fourier transform infrared spectra (FTIR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM) proved that the successful preparation of composite microfiber membrane with core-shell structures. At the same time, the PANI had an effect of protection on PI nanofiber, which was detected by thermal gravimetric analysis (TGA). The orthogonal experiments were designed to determine the optimal reaction conditions for the conductivity of PANI/PI microfiber membranes as following: ANI concentration (0.15 mol L−1), APS concentration (0.1 mol L−1) and DBSA concentration (0.3 mol L−1). The conductivity of PANI/PI microfiber membranes could arrive to 3.83 × 10−2 S cm−1. Moreover, the PANI/PI microfiber membranes had a superior hexavalent chromium (Cr (VI)) adsorption performance. The factors affecting the performance of hexavalent chromium (Cr (VI)) removal from the aqueous solutions were investigated.

Effect of dodecyl benzene sulfonic acid (DBSA) and lauric amine (LA) on the associating state and rheology of heavy oils

Abstract The effects of two amphiphiles, DBSA and LA, on the associating state and viscosity of three heavy oils with different resin/asphaltene (R/A) mass ratios were investigated through DSC analysis, rheological test and electrical conductivity measurement. The wax appearance temperatures of the three heavy oils are lower than 40 °C. The viscosity of heavy oils at temperature range 50~70 °C increases with increasing DBSA concentration but decreases with increasing LA concentration. Addition of DBSA increases the electrical conductivity of heavy oils, which implies that the DBSA acts as asphaltene dispersants; the electrical conductivity of heavy oils decreases after LA addition, which implies that the LA acts as asphaltene flocculants. The addition of DBSA decreases the size of asphaltene particles and generates new solvation layers, both of which favor the increase of heavy oil viscosity; the addition of LA increases the size of asphaltene particles and releases some liquid oils bounded by asphaltene particles, both of which favor the decrease of heavy oil viscosity. With the increase of R/A mass ratio, the stability of heavy oils increases while the viscosity enhancing/reducing efficiency of DBSA/LA decreases.

Temperature- and magnetic field-dependent electrical transport studies of poly(-3,4 ethylenedioxythiophene) nanoparticles

Poly(3,4-ethylenedioxythiophene) nanoparticles with average diameter of 13 nm have been synthesized by oxidative polymerization method using dodecylbenzene sulfonic acid (DBSA) as surfactant. Thermogravimetric analysis shows the improvement of thermal stability with increasing surfactant concentration. The red shifting of the 1,381 cm−1 band with increasing DBSA concentration indicates the transition from benzenoid to quinoid structure. The temperature dependence of resistivity reveals that the charge transport takes place through variable range hopping (VRH) mechanism. The slopes of reduced activation versus temperature plot confirm that the charge transport takes place through 3D VRH mechanism. The negative slope of the reduced activation energy versus temperature plot indicates that our samples fall in the insulating regime. Magnetoresistance study shows a transition from positive to negative with increasing temperature. The negative value of magnetoresistance at higher temperature is due to the quantum interference effect where the charge carrier hopping distance in comparable to the localization length and the positive magnetoresistance at low temperature results due to the shrinkage of impurity orbitals under magnetic field. The higher value of positive magnetoresistance than that of the negative magnetoresistance indicates that wave function shrinkage effect is stronger compared to quantum interference effect.

Biocatalyzed synthesis of conducting polyaniline in reverse microemulsions

A green and efficient reaction system containing hydrogen peroxide and hemoglobin in dodecylbenzenesulfonic acid (DBSA) reverse microemulsions was developed for the polymerization of aniline. The effect of water content (Wo), reaction time, concentrations of DBSA, aniline and H2O2 were carefully examined. It was found that the conductivity of polyaniline (PANI) changed with the water content. The highest conductivity of 0.90S/cm was obtained when Wo was 22.5. UV–vis spectra, Fourier transform infrared and X-ray diffraction spectra indicated the formation of conducting PANI doped with DBSA. The DBSA-doped PANI was nanoscaled, furcate shape according to scanning electron microscopy and transmission electron microscopy. From thermogravimetric analysis, it was found the product was obtained with excellent thermal stability. In comparison with other enzymatic polymerization systems, the new system gave higher reaction efficiency, higher conductivity and thermal stability of PANI.

Synthesis and Characterization of Processable Polyaniline Salts

Polyaniline (PANI) is one of the most promising candidates for possible technological applications. PANI has potential applications in batteries, anion exchanger, tissue engineering, inhibition of steel corrosion, fuel cell, sensors and so on. However, its insolubility in common organic solvents limits its range of applications. In the present study an attempt has been made to synthesize soluble polyaniline salt via inverse polymerization pathway using benzoyl peroxide as oxidant and dodecylbenzenesulfonic acid (DBSA) as dopant as well as a surfactant. A mixture of chloroform and 2-butanol was used as dispersion medium for the first time. The influence of synthesis parameters such as concentration of aniline, benzoyl peroxide and DBSA on the yield and other properties of the resulting PANI salt was studied. The synthesized PANI salt was found to be completely soluble in DMSO, DMF, chloroform and in a mixture of toluene and 2-propanol. The synthesized polymer salt was also characterized with cyclic voltam-metry, SEM, XRD, UV-Vis spectroscopy and viscosity measurements. TGA was used to analyze the thermal properties of synthesized polymer. The extent of doping of the PANI salt was determined from UV-Vis spectra and TGA analysis. The activation energy for the degradation of the polymer was calculated with the help of TGA.

All-organic PANI–DBSA/PVDF dielectric composites with unique electrical properties

Novel all-organic polymer high-dielectric permittivity composites of polyaniline (PANI)/poly (vinylidene fluoride) (PVDF) were prepared by solution method and their dielectric and electric properties were studied over the wide ranges of temperatures and frequencies. To improve the interface bonding between two polymers, dodecylbenzenesulfonic acid (DBSA), a bulky molecule containing a polar head and a long non-polar chain was used both as a surfactant and as dopant in polyaniline (PANI) synthesis. Synthesized conducting PANI–DBSA particles were dispersed in poly(vinylidene fluoride) (PVDF) matrix to form an all-organic composite with different PANI–DBSA concentrations. Near the percolation threshold, the dielectric permittivity of the composites at 100 Hz frequency and room temperature was as high as 170, while the dielectric loss tangent value was as low as 0.9. Like typical percolation system, composites experienced high dielectric permittivity at low filler concentrations. However, their dielectric loss tangent was low enough to match with non-percolative ceramic filler-based polymer composites. Maximum electrical conductivity at 24 wt% of PANI–DBSA was mere 10−6 S/cm, a remarkably low value for percolative-type composites. Increase in the dielectric permittivity of the composites with increase in temperature from 25 to 115 °C for different PANI–DBSA concentrations was always in the same range of 50–60 %. However, the degree of increase in the electrical conductivity with the temperature was more prominent at low filler concentrations compared with high filler concentrations. Distinct electrical and their unique thermal dependence were attributed to an improved interface between the filler and the polymer matrix.

The effect of dopant on structural, thermal and morphological properties of DBSA-doped polypyrrole

Polypyrrole is prepared with different molar ratios of dodecylbenzene sulfonic acid (DBSA) (0.1, 0.2, 0.3 and 0.4) by in situ chemical polymerization method. The reaction temperature was 0–5 °C for 24 h. The FTIR spectrum confirmed the attachment of sulfonyl group in the pyrrole structure. The intensity of polypyrrole increased with increase in sulfur content. SEM graphs revealed the granular morphology of the doped polymer surface. DBSA has had strong effect on morphology with formation of aggregated particles at higher concentrations. Higher concentration of DBSA-doped PPy shows higher thermal stability. The promotion of electron from ground state to excited state of polypyrrole is confirmed by UV spectroscopic studies. Various sizes in particle distribution of DBSA-doped PPy were analyzed by a particle size analyzer. Solubility of polypyrrole was determined at room temperature. The solubility and quantity of polypyrrole increased with higher dopant concentration. Current–voltage (I–V) characteristics were carried out over the temperature range 313–343 K, which was found to be linear. The conductivity of doped-PPy showed high conductivity at low concentration of dopant while, conductivity decreased with increasing concentration of DBSA. The higher doping level of DBSA was confirmed by elemental analysis.

The nucleation study on the cationic miniemulsion polymerization of octamethylcyclotetrasiloxane (D4)

The nucleation of the cationic miniemulsion polymerization of octamethylcyclotetrasiloxane (D4) has been investigated in detail in this work. The particle size was traced by dynamic laser scattering in the polymerization process using different concentration of dodecylbenzenesulfonic acid (DBSA) as both the initiator and surfactant. The results reveal the progressively decreasing particle sizes with the steadily increasing monomer conversion. The descending particle sizes can be explained by the existence of homogeneous nucleation of hydroxyl-terminated polydimethylsiloxane (PDMS) oligomers in addition to the primary droplet nucleation. A linear relationship between the natural logarithm of the average particle diameter (lnd(t)) and the natural logarithm of the monomer conversion (lnf(t)) is then deduced based on the theory, which has been validated by the experimental data. The slope of lnd(t)~lnf(t) line relies on the parameter of K which is the ratio of PDMS oligomers entering water phase to all PDMS oligomers produced. The influence of DBSA concentration on the K and the fraction of homogeneous nucleation (F(H)) has been then obtained. Both of the values of K and F(H) increase with the increasing DBSA concentrations.

Mixed‐surfactant‐induced morphology change of polyaniline

AbstractIn this study, polyaniline (PANI) was synthesized in the presence of a mixture of two surfactants, dodecylbenzene sulfonic acid (DBSA) and sodium dodecyl sulfate (SDS). The morphology of PANI observed under transmission electron microscopy was found to be spherical and cylindrical shapes. At low DBSA concentrations (2 and 10 mM), the addition of SDS made it easier to obtain the cylindrical morphology of PANI. A scheme based on the deformation and coagulation of mixed micelles was proposed to explain the morphological change of PANI. In the system of 10 mM DBSA, when the SDS concentration was 2 mM, the tubular morphology of PANI was observed, whereas when the SDS concentration was increased, a fiber morphology of PANI was found. The relative ratio of anilinium cations to free aniline played a key role in whether the tube or fiber morphology existed. Finally, a significant improvement in the conductivity of PANI was achieved when PANI had a cylindrical morphology. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Kinetic Study of Polyaniline Film Formation Using Ferric Chloride/Ammonium Persulfate as Composite Oxidant

Polyaniline (PANI) was synthesized by in situ emulsion polymerization. The kinetics of the PANI film formation was investigated by the quartz crystal microbalance technique (QCM). PANI film doped with dodecylbenzenesulfonic acid (DBSA) was synthesized by emulsion polymerization using ferric chloride/ammonium persulfate (FeCl3/APS) as composite oxidant in the presence of a constant (0.4 T) magnetic field (MF). The results showed that the peak current and conductivity of PANI synthesized by composite oxidant was higher than that synthesized by APS in the presence of an MF and it was also suggested that the PANI/FeCl3 composite has higher conductivity than pure PANI. The reaction exhibited first order with respect to composite oxidant, half-order to aniline, and half-order to DBSA, and the activation energy calculated from the temperature dependence of the growth rate was 40.23 kJ/mol. The polymerization conditions of aniline were optimized tentatively by cyclic voltammetry testing, which was studied by using carbon paper–loaded PANI as a working electrode for the first time. The experimental results indicated that the peak currents and conductivity of PANI were the largest under the following conditions: MF intensity of 0.4 T, composite oxidant concentration of 0.18 mol/L, and concentrations of aniline and DBSA of 0.08 mol/L and 0.05 mol/L, respectively.

Effect of dodecyl benzene sulfonic acid on the preparation of polyaniline/activated carbon composites by in situ emulsion polymerization

Polyaniline (PANI)/activated carbon (AC) composites are prepared by in situ emulsion polymerization using dodecyl benzenesulfonic acid (DBSA). DBSA can play a role as both surfactant and dopant in the process of PANI synthesis. The effect of DBSA on the preparation of PANI/AC composites is investigated in this research. For this purpose, the composites are prepared in micellar solutions with various concentrations of DBSA. It is confirmed using X-ray diffraction (XRD) analysis and Fourier-transform IR (FT-IR) spectroscopy that DBSA actually participates in the PANI doping process. The PANI doped with DBSA (DBSA-PANI) covering the AC surfaces is observed with scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrochemical properties of the composites are studied by cyclic voltammetry (CV). The composites show different values of specific capacitance, which was found to be a function of DBSA concentration. The composite prepared in 0.045 M DBSA solution shows the highest specific capacitance (115.2 F g −1) among the prepared composites. The doping level of DBSA-PANI is increased with the concentration of DBSA in solution.

The Electrochemical Polymerization of Polypyrrole Microstructures in an Aqueous Solution of Dodecylbenzenesulfonic Acid

Conducting polymer – polypyrrole (PPy) microstructures were fabricated in an aqueous solution of dodecylbenzenesulfonic acid (DBSA) by electrochemical polymerization. The study implied the concentration of DBSA had great effect on the morphologies and conductivities of PPy microstructures. At lower DBSA concentration (0.2M), no obvious microstructures were generated. Increasing DBSA concentration, some novel “chayote-like”, “flower-like” microstructures were obtained by modulating electrochemical conditions. The growth process of microstructures was studied by scanning electron microscopy and relevant mechanism was discussed. Raman characterizations indicated that the microstructures were made of conductive PPy doped by DBSA.

Kinetic study on the ring-opening polymerization of octamethylcyclotetrasiloxane (D4) in miniemulsion

A kinetic study on the ring-opening polymerization (ROP) of octamethylcyclotetrasiloxane (D4) in miniemulsion is presented in this work. The polymerization is initiated by dodecylbenzenesulfonic acid (DBSA) which also serves as the surfactant (inisurf). The influence of the size of monomer droplet and the concentration of DBSA on the polymerization rate were studied. Since the main place for the ROP of D4 was confirmed to be at the oil/water interface, a three-layer interface model was proposed to analyze the distribution of molecules at the interface and the effects of DBSA. A kinetic equation is then developed based on this model. In the equation, the polymerization rate (Rp) is related to the initial monomer concentration ([D4]0), the droplet radius (r), the coverage of DBSA on monomer droplets surface (x). The polymerization rate can be predicted from the kinetic equation feeding all parameters with their experimental values. Finally, the equation gave a good accordance between the predicted polymerization rate data and the experimental results under different polymerization conditions.

Effects of FeCl3/ammonium persulfate composite oxidant and magnetic field on film growth rate of polyaniline doped with dodecylbenzenesulfonic acid

Polyaniline (PANI) doped with dodecylbenzenesulfonic acid (DBSA) was synthesized by emulsion polymerization using FeCl3/ammonium persulfate (APS) as composite oxidant. The effects of different magnetic field (MF) intensities, the molar ratios of FeCl3/APS, and the concentrations of DBSA on the film growth rate of PANI were analyzed by using a quartz crystal microbalance (QCM) technique. The film growth rate of PANI increased with increasing MF intensity and the concentration of DBSA. However, the film growth rate of PANI decreased with increasing molar ratio of FeCl3/APS. The polymerization conditions were optimized tentatively by cyclic voltammetry (CV) testing. The peak currents and conductivity were the largest for PANI prepared under the following conditions: MF intensity 0.4 T, molar ratio of FeCl3/APS 2:1, and concentration of DBSA 0.05 mol/L. The UV–Vis spectra of the PANI polymerization showed that the absorption intensity of PANI polymerized in the presence of MF was greater than that of PANI polymerized in the absence of MF, at the same reaction time.

Synthesis of polyaniline/multiwall carbon nanotube composite via inverse emulsion polymerization

AbstractThe composite of polyaniline (PANI) and multiwall carbon nanotube carboxylated through acid treatment (c‐MWCNT) was synthesized by chemical oxidative polymerization in an inverse emulsion system. The resultant composites were compared with products from aqueous emulsion polymerization to observe the improvements in electrical conductivity, structural properties, and thermal stability obtained by this synthetic method. Prior to the inverse emulsion polymerization, MWCNT was treated with a strong acid mixture to be functionalized with carboxylic acid groups. Carboxylic acid groups on surfaces induced selective dispersibility between polar and nonpolar solvents because of the increase of hydrophilicity. As the content of c‐MWCNT was increased, the electrical conductivity was increased by a charge transport function from the intrinsic electrical conductivity of MWCNT and the formation of a highly ordered dense structure of PANI molecules on the surface of c‐MWCNT. The images observed with electron spectroscopy showed the capping of c‐MWCNT with PANI. The growth of additional ordered structures of PANI/c‐MWCNT composite, which was observed through wide‐angle X‐ray diffraction patterns, supported the capping by PANI. It was observed that the doping of the composite had a significant relationship with the concentration of dodecylbenzenesulfonic acid (DBSA). The thermal stability of PANI composite was improved by the addition of c‐MWCNT; this was thought to be related with structure ordering by inverse emulsion polymerization. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 2255–2266, 2008

Micellar Peroxidase-Catalyzed Synthesis of Chiral Polyaniline

Micellar peroxidase-catalyzed synthesis of chiral polyaniline (PANI) in the presence of dodecylbenzenesulfonic acid (DBSA) was developed. The effect of DBSA concentration on the catalytic efficiency of horseradish and palm tree peroxidases was examined. Favorable conditions for the enzymatic synthesis of chiral PANI, determined by a multiple factors design, demonstrated that the PANIs with the highest chirality were produced in the presence of low concentrations of optically active camphorsulphonic acid (CSA). Unexpectedly, the chiral PANI was also synthesized in the absence of CSA in feed. The favorable conditions for the enzymatic production of chiral and conducting PANIs were shown to be different. The morphology of the chiral PANI particles was examined by transmission and scanning electron microscopies.