Ester Sulfonic Acid Research Articles

Study on gas–liquid sulfonation reaction under annular flow pattern in micro-reactor: Mechanism, model and process optimization

Micro-sulfonation is a new sulfonation method with great development potential. The gas–liquid micro-sulfonation are safe, efficient and low-cost, however, limited by the research progress and application scope of micro-reactors, the development of gas–liquid micro-sulfonation technique is far from enough. The gas–liquid sulfonation reaction process under annular flow pattern in micro-reactor is experimentally studied in this paper. The maximum MESA (fatty acid methyl ester sulfonic acid) yield under the experimental conditions in this study achieves 89.771 %, which is obviously higher than that (64.1 % for gas–liquid sulfonation and 76.82 % for liquid–liquid sulfonation) in conventional reactors and should be higher if the micro-reactor structure or operating conditions being further optimized. Based on the analyses of experimental results, the effect mechanisms of mass transfer and reaction on the gas–liquid micro-sulfonation efficiency are explored, and the sulfonation efficiency models and pressure drop model of four micro-reactors are established by dimensional analysis method. On account of both the mass transfer characteristics of gas–liquid two-phase flow and the high-viscosity of sulfonation products, enhancing the local disturbance of liquid phase can significantly improve the reaction efficiency. Finally, the operating conditions of two-phase flow rates and reaction time are optimized to ensure the high sulfonation product yield meanwhile reduce the fluid pressure drop or energy consumption of sulfonation process using the improved NSGA-II algorithm.

Techno-Economic-Environmental Analysis of Sustainable Anionic Biosurfactant Production from Palm Fatty Acid Distillate.

Currently, there is increased interest in biosurfactants as a substitute for surfactants synthesized from petroleum due to their superior properties and biodegradability. Palm oil derivatives, which can be converted to various products, were selected for biosurfactant synthesis. This paper simulated the biosurfactant production process from palm fatty acid distillate, that is, methyl ester sulfonate (MES), alkyl sulfate, alkyl phosphate, and alkyl carboxylate. Aspen Plus software was used to estimate the thermodynamic properties of intermediate aliphatic organic acids, e.g., methyl ester sulfonic acid, fatty alcohol sulfuric acid, and fatty alcohol phosphoric acid. The chemical process equipment was designed and evaluated to be used in techno-economic analysis, with comparison to petroleum source surfactant production, that is, sodium dodecylbenzenesulfonate (SDBS). The total production cost of each biosurfactant was expressed in terms of minimum selling price. The profitability of each project was determined and compared using three economic indicators: net present value (NPV), payback period, and internal rate of return (IRR). The life cycle assessment methodology was then used to evaluate the environmental impact of surfactant production. The results showed that all surfactant production processes, except for alkyl phosphate, were attractive alternatives as the project yielded a positive value of NPV. The highest NPV of 13.1 million USD was obtained from the MES production process, while the maximum IRR of 79.81% and payback period of 1.49 years were obtained from the alkyl carboxylate production process at a capacity of 1 ton/h. However, the sulfate production process caused more environmental impact than the other two surfactants (MES and carboxylate) due to more CO2 emission per product unit at the level of 2.88 tons CO2/ton surfactant, which is also more than the SDBS surfactant production process that released 2.46 tons CO2/ton surfactant.

The effect of solvent type and temperature on mono-diacylglycerol purification

Mono-diacyl glycerol (M-DAG) resulted from esterification reaction between palm fatty acid distillates (PFAD) and glycerol with catalyst of methyl ester sulfonic acid, has low purity caused by the remaining catalyst, free fatty acids, free glycerol and triacylglycerol. Purification can be carried out by saponification and crystallization. The purpose of this study was to determine the most suitable solvent (96% ethanol, 70% ethanol, 95% isopropyl alcohol), and followed by determination of temperature level (2 °C, 5 °C, 10 °C) in crystallization step to obtain pure and high yield of M-DAG. Analyses that were carried out included yield, visual appearance, free fatty acid (FFA) content, and emulsion stability. The results showed that the type of solvent had an effect on the yield and free fatty acids, but did not affect the emulsion stability. Temperature also affected the yield and free fatty acids content, but did not affect the emulsion stability. The most suitable solvent was 96% ethanol with a yield of 24.2%, FFA content of 29.6%, and emulsion stability of 49.5%. The best temperature for crystallization was at 2 °C with a yield of 16.23%, FFA content of 3.80%, and emulsion stability of 100%.

PEMURNIAN MONO-DIASILGLISEROL HASIL ESTERIFIKASI PALM FATTY ACID DISTILLATE DAN GLISEROL DENGAN EKSTRAKSI PELARUT-SAPONIFIKASI DAN DISTILASI MOLEKULER

Mono-diacylglycerol (M-DAG) is one of potential palm oil derived products to be developed. Palm Fatty Acid Distillate (PFAD) and glycerol esterification using Methyl Ester Sulfonic Acid (MESA) catalyst produced M-DAG that consist of Free Fatty Acid (FFA) and Triacylglycerol (TAG) fractions. FFA and TAG fractions can reduce the M-DAG emulsifier quality. Therefore, purification process is needed to eliminate FFA and TAG fractions. The purpose of this research was to improve the M-DAG emulsifier quality by purification process. The purification was performed in two ways: solvent extraction - saponification and molecular distillation. Solvent extraction - saponification was done with the addition of 0, 10, 15 and 20% (w/w) NaHCO3. The result showed that the addition of 20% (w/w) NaHCO3 was the best treatment. It was able to produce 43.52% yield of M-DAGconsisted of 44.48% Thin-Layer Chromatography (TLC) in FFA+TAG composition, 31.05% MAG, 24.47% DAG, melting point of 44.83oC, free fatty acid level of 19.43%, pH value of 6, emulsion stability of 51.21% for 12 hours, has a white color, dry texture, and odorless. The molecular distillation at temperature of 100-180oC on purification process was carried out to separatethe FFA. Molecular distillation had produced distillate and residue. Molecular distillation was an effective process to separate the FFA from M-DAG whereas produced 96.09% of FFA from distillation flow.Keywords : glycerol, molecular distillation, palm fatty acid distillate, purification, saponification

Optical properties of Cu and Ru doped BST thin films with additive glycerol and MESA surfactant

In this paper, barium strontium titanate (BST) thin films were deposited by chemical solution deposition (CSD) with addition glycerol and methyl ester sulfonic acid (MESA) surfactant as additive materials. The effect of variation spinning speed (5500 and 8000 rpm), different dopant (Cu and Ru dopants), and also additive materials on optical properties were studied by Spectrophotometer Vis-NIR. As a result, BST thin films with additive MESA have higher absorbance and similar spectrum pattern than additive glycerol. Generally, BST thin films with MESA surfactant had band gap smaller than glycerol of BST thin films. Absorption and extinction coefficient of BST with glycerol were observed and we reported Ru doped BST at spinning speed 5500 rpm had higher value than other films. On other hand, Cu doped BST at 8000 rpm had absorption and extinction coefficient higher than other films.

SINTESIS SURFAKTAN ALKIL POLIGLIKOSIDA (APG) BERBASIS DODEKANOL DAN HEKSADEKANOL DENGAN REAKTAN GLUKOSA CAIR 75%

Alkyl poliglucosides (APG) is nonionic surfactant prepared from renewable raw materials based on carbohydrate and vegetable oils namely glucose and fatty alcohol. Glucose is the main raw material which is supplied the hydrophilic group, and fatty alcohol as hydrophobic group. APG was prepared using fatty alcohol varying in chain lengthsof C12 and C16 by two step methods (butanolysis and transasetalisation process). The catalyst of methyl ester sulfonic acid (MESA) was added. The effect of catalyst concentrations (1.5, 2, and 2.5%) was investigated. The product evaluated for surface active properties. The chemical structures of the products were confirmed using fourier transform infrared spectroscopy (FTIR).The effects of fatty alcohol and concentration of catalyst were not significantly different to the pH and density. The result showed that reduction surface tension, reduction interfacial tension, and emulsion stability increased with increasing alkyl chain length and foam height decreases as the alkyl chain length increases. The best APG was obtained from C16 fatty alcohol (hexadecanol) and 2.5% of MESA catalyst, with the ability to reduce surface tensions at 1% concentration were 68.12%; the ability to reduce interfacial tensions of 98.14%, stability of emulsion of64%, foam height of 7.12% and pH of 7.69. Keywords: alkylpoliglycoside, fatty alcohol, glucose, surfactant

Nanoporous and proton conductive hydrophobic-hydrophilic copolymer thermoset membranes

Copolymers of hydrophobic diglycidyl ether of bisphenol A (DGEBA) vinyl ester (VE) and hydrophilic 2-acrylamido 2-methyl 1-propane sulfonic acid (AMPS) were evaluated as proton conducting membranes for fuel cell applications. Membranes were synthesized using free radical copolymerization in the presence of a common solvent for both monomers, dimethyl formamide (DMF), followed by solvent removal by supercritical CO2 to induce porosity. Micrographs revealed pore sizes below 60 nm with porosity proportional to the initial solvent fraction used. Studies on the states of water showed that the presence of this pore volume significantly altered the freezable water fraction at equivalent AMPS concentrations. Comparison of the moles of water per mole of sulfonic acid (λ) between copolymer membranes and AMPS monomer solutions showed that the nonfreezable water (λ|nonfr) was depressed at high AMPS concentrations, suggesting that differences in interatomic distances between sulfonic acid groups might alter λ|nonfr. The highest average through plane conductivity of membranes was determined to be 30 mS/cm and was comparable to that of Nafion®117 (27 mS/cm). The effective proton mobility, μeff, was calculated and suggested to be a parameter used to capture the effects of membrane structure and swelling while acting as a comparison between different membrane types. Fuel cell tests on membranes at low ion exchange capacities were compared to Nafion®117, with suggestions on improvements of copolymer structures for improved performance. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1245–1255, 2010

Highly sensitive electrogenerated chemiluminescence produced at in Eastman-AQ55D-carbon nanotube composite film electrode

The electrochemistry and electrogenerated chemiluminescence (ECL) of tris(2,2′-bipyridyl)ruthenium(II) ion-exchanged in Eastman-AQ-carbon nanotube (CNT) composite films were investigated at a glassy carbon (GC) electrode. Eastman-AQ55D is a poly (ester sulfonic acid) cation exchanger available in a commercial dissolved form. It is much more hydrophilic than Nafion due to its unique structure, so Ru(bpy)32+ does not diffuse into the hydrophobic region where it may lose its electroactivity as that in Nafion. The interfused CNT could act as electronic wires that connect the electrode with Ru(bpy)32+, which made the composite film much more electronically conductive. Besides, the negatively charged CNT could also absorb some Ru(bpy)32+ which finally led to the increasing of Ru(bpy)32+. Moreover, the strong electrostatic interaction between AQ and Ru(bpy)32+ made the composite films much more stable. The combination of AQ and CNT brings excellent sensitivity with the detection limit as low as 3 × 10−11 M for TPA.

Buildup of Polyelectrolyte−Protein Multilayer Assemblies on Gold Electrodes. Role of the Hydrophobic Effect

The buildup of layer-by-layer assemblies onto gold surfaces from water-soluble charged polyelectrolytes and proteins is examined using quartz crystal microgravimetry (QCM) and electrochemical techniques. Polyelectrolytes such as poly(styrenesulfonate) and poly(ester sulfonic acid) (Eastman AQ-29D polymer) adsorb spontaneously onto gold, contrary to poly(ethyleneimine). From the modification of the gold surface with a thiol and specific adsorption of polymers under polarization conditions, it is concluded that the hydrophobicity of the gold surface seems to be a determining factor in the adsorption process. Alternate adsorption onto gold resonators first coated with AQ-29D polymer gives stable multilayer films in the case of positively charged lysozyme (pI = 11) or polyheme Desulfovibrio vulgaris Hildenborough cytochrome c3 (pI = 10.5). QCM frequency changes with the number of adsorption steps suggest that a linear increase in film mass occurs. Desulfomicrobium norvegicum polyheme cytochrome c3 (pI = 7), which has a null global charge at neutral pH, is shown to give also stable multilayer AQ-29D/cytochrome c3 films, suggesting that several types of interactions, especially the hydrophobic effect, are involved in the buildup process.

Quartz crystal microbalance and voltammetry monitoring for layer-by-layer assembly of cytochrome c3 and poly(ester sulfonic acid) films on gold and silver electrodes

Films made from polyheme cytochrome c 3 and the ionomer poly(ester sulfonic acid) AQ-29D or poly(styrenesulfonate) have been assembled by alternate layer-by-layer adsorption onto gold or silver electrodes. The build up of the multilayer structure has been monitored using quartz crystal microbalance and voltammetry techniques. AQ-29D polymer has been shown to form one stable monolayer film attached to metal electrodes. By using thus-modified-AQ-29D electrodes, successive layers of cytochrome c 3 and AQ-29D were deposited by alternate immersion in the respective solutions of protein and polymer. Alternate adsorption cycles have been repeated up to the construction of eight successive monolayers. Decreases in the coverage of redox active cytochrome on adsorption of the AQ-29D polymer layer on a sub-layer of cytochrome are observed. They can be explained on the basis of peel off of protein, or protein+AQ polymer, toward the solution. Several film construction strategies have been tested by varying the pre-treatment of the metal electrode surface using positively or negatively charged species, or the nature of (monoheme or polyheme) cytochrome. AQ-29D films have been shown to exhibit the twofold role of polyanionomer and incorporating matrix, very promising for further development in biotechnologies.

Analysis of sulfoxylated methyl esters (Φ-MES): Sulfonic acid composition and isomer identification

Derivatization of a C12Φ-methyl ester sulfonic acid by using iodide-trifluoroacetic anhydride in dimethylformamide in a one-step reaction yielded derivatized sulfonic thiotrifluoroacetates. The latter have been analyzed by gas chromatography-mass spectrometry (MS) and liquid chromatography-MS techniques so that, for the first time, the acid composition and the mono sulfonic acid isomer distribution are shown.

Assembly of Electroactive Layer-by-Layer Films of Myoglobin and Ionomer Poly(ester Sulfonic Acid)

Layer-by-layer films were assembled on solid substrates by alternate adsorption of negatively charged ionomer poly(ester sulfonic acid) or Eastman AQ55 from its aqueous dispersion and positively charged myoglobin (Mb) from its solution at pH 4.5. The film assembly process was monitored by cyclic voltammetry (CV), UV–vis spectroscopy, and quartz crystal microbalance (QCM). {AQ/Mb} n films grown on pyrolytic graphite (PG) electrodes showed a pair of well-defined and nearly reversible CV peaks at about −0.20 V vs Ag/AgCl in pH 5.5 buffers, characteristic of the Mb heme Fe(III)/Fe(II) redox couple. Although the amount of Mb adsorbed in each bilayer was essentially the same, the fraction of electroactive Mb decreased dramatically with an increase of bilayer number ( n). Soret absorption bands of {AQ/Mb} n films on glass slides suggest that Mb in the films retains its native state in the medium pH range. Trichloroacetic acid, oxygen, and hydrogen peroxide were electrochemically catalyzed by {AQ/Mb} 6 films with significant lowering of reduction overpotential.

Direct electrochemistry and electrocatalysis with horseradish peroxidase in Eastman AQ films

Stable films made from ionomer poly(ester sulfonic acid) or Eastman AQ29 on pyrolytic graphite (PG) electrodes gave direct electrochemistry for incorporated enzyme horseradish peroxidase (HRP). Cyclic voltammetry of HRP–AQ films showed a pair of well-defined, nearly reversible peaks at about −0.33 V vs. SCE at pH 7.0 in blank buffers, characteristic of HRP heme Fe(III)/Fe(II) redox couple. The electron transfer between HRP and PG electrode was greatly facilitated in AQ films. The electrochemical parameters such as apparent heterogeneous electron transfer rate constant ( k s) and formal potential ( E°′) were estimated by fitting the data of square-wave voltammetry (SWV) with nonlinear regression analysis. Reflectance absorption infrared (RAIR) and UV–Vis absorption spectra demonstrated that HRP retained a near native conformation in AQ films. The embedded HRP in AQ films retained the electrocatalytic activity for oxygen, nitrite and hydrogen peroxide. Possible mechanism of catalytic reduction of H 2O 2 with HRP–AQ films was proposed.

Hydrogen peroxide biosensor based on sol–gel-derived glasses doped with Eastman AQ polymer

A hydrogen peroxide biosensor based on sol–gel-derived glasses doped with poly(ester sulfonic acid) Eastman AQ 55D was constructed. Thionine (TH), as a mediator, was incorporated in this matrix by electrostatic force between TH + and the negatively charged sulfonic acid group in Eastman AQ polymer. Performance and characteristics of the sensor were evaluated with respect to response time, sensitivity and storage stability. The enzyme electrode has a sensitivity of 11.36 μA mM −1 with a detection limit of 5.0×10 −7 M H 2O 2, and the sensor achieved 95% of the steady state current within 20 s.

Detection of Chemically Induced DNA Damage by Derivative Square Wave Voltammetry

Damage of DNA films after reaction with styrene oxide was detected using derivative square wave voltammetry. Double-stranded (ds) DNA films with initially low backgrounds developed oxidation peaks for DNA bases during incubation with styrene oxide. Films were prepared on pyrolytic graphite (PG) electrodes by casting mixtures of DNA with the poly(ester sulfonic acid) ionomer Eastman AQ38S or by covalent binding of DNA onto oxidized PG. While both types of films gave oxidation peaks in the region 0.6-1.1 V vs SCE after incubations with styrene oxide, DNA/AQ films gave the best signal-to-background ratios. Damage of DNA by reaction with styrene oxide under the electrode incubation conditions was confirmed by capillary electrophoresis. Total integrals of oxidation peaks increased with time of incubation with styrene oxide. Relative peak heights depended on the type of DNA in the order calf thymus ds DNA > salmon sperm ds DNA > supercoiled ds DNA > highly polymerized calf thymus ds DNA.

Bioelectrochemical dehalogenations via direct electrochemistry of poly(ethylene oxide)-modified myoglobin

Catalytic reductive dehalogenation of hexachloroethane (HCE) was shown to be possible using a graphite electrode coated with a film of the poly(ester sulfonic acid) containing myoglobin (Mb). The effectiveness of the dehalogenation was limited by the solubility of HCE in aqueous solutions. In order to produce an electrode that could dehalogenate HCE in non-aqueous solutions, Mb was chemically modified by addition of poly(ethylene oxide) (PEO). The PEO–Mb–AQ29D modified electrode was found to be suitable for the reductive dehalogenation of HCE in ethanolic solutions. The catalytic response was shown to be linearly dependent on the bulk concentration of HCE.

Electrochemical generation of ferrylmyoglobin during oxidation of styrene with films of DNA and a poly(ester sulfonic acid) ionomer

The chemistry of electrochemically-driven myoglobin-catalyzed oxidation of styrene was investigated in films of DNA or Eastman AQ ionomer on optically transparent electrodes. Conversion of styrene to styrene oxide proceeded via a ferrylmyoglobin radical intermediate. Ferrylmyoglobins were clearly detected by spectroelectrochemistry in films of 1–4 mm thick. The ferrylmyoglobin radical is produced by reaction of metmyoglobin (Mb) in the films with hydrogen peroxide formed by electrochemical catalytic reduction of oxygen catalyzed by Mb. Thus, electrochemically-driven styrene oxidation with these films proceeds by a ‘doubly catalytic’ electrode-driven reduction–oxidation pathway. Ferrylmyoglobin formation during electrolysis of Mb–DNA films in aerobic solutions was much faster, and styrene oxidation occurred with less Mb decomposition compared to the Mb–AQ films. The better performance of Mb–DNA films is correlated with a larger fraction of electroactive Mb and better stability than for the Mb–AQ films.

Poly(ester–sulfonic acid): modified carbon electrodes for the electrochemical study of c-type cytochromes

Various mono- and polyheme c-type cytochromes are able to spontaneously incorporate within thin films made from the ionomer poly(ester–sulfonic acid) Eastman AQ-29D acting as cation-exchange films cast on carbon electrodes. AQ-films as evidenced from scanning electron microscopy are uniform. The electron transfer within this cation-exchange film is strongly affected by the film thickness. The performances of the AQ-films to incorporate cytochromes by varying pH are examined on the basis of electrostatic interactions which principally govern the incorporation process. From film-transfer experiments, a model consisting of a two-phase ionomer coating has been developed for cytochrome c. An indirect approach based on the study of the incorporation of nonelectroactive proteins and peptides is reported. The respective abilities of AQ-29D and Nafion films to incorporate/not to incorporate c-type cytochromes and other `low molar mass' species are explained by the formation of hydrated gel-like AQ-films.

Enhanced electron transfer for hemoglobin in poly (ester sulfonic acid) films on pyrolytic graphite electrodes

Stable films made from the ionomer poly (ester sulfonic acid) Eastman AQ55 on pyrolytic graphite (PG) electrodes gave reversible voltammetry for the incorporated protein hemoglobin (Hb). Cyclic voltammetry of Hb-AQ films showed a pair of well-defined, reversible peaks at about −0.04 V versus SHE at pH 5.5. Compared to solutions, electron transfer between Hb and PG electrodes was greatly facilitated in the AQ films. Soret absorption band positions suggest that Hb retains a near native conformation in AQ films in the medium pH range. The formal potential of the Hb heme Fe(III)/Fe(II) couple in AQ films shifted linearly between pH 4 and 11 with a slope of −52 mV pH−1, suggesting that one proton transfer is coupled to each electron transfer in the electrochemical reaction. Square wave voltammograms of Hb-AQ films were fit by nonlinear regression analysis using a model featuring dispersion of formal potentials. Hb can act as an enzyme-like catalyst in these films as demonstrated by catalytic reduction of trichloroacetic acid with significant decreases in the electrode potential required.

Kinetic studies on the electron transfer between various c-type cytochromes and iron (III) using a voltammetric approach

Cyclic voltammetry was used here to investigate the kinetics of the electron transfer between a soluble iron(III) complex and several cytochromes isolated from Desulfovibrio and Desulfuromonas species. The second order rate constants were calculated and found to be in the 10 5–10 6 M −1 s −1 range. Their values are discussed from the point of view of the redox potentials, heme content and pI value of the proteins. The ability of poly(ester–sulfonic acid) ionomer (Eastman AQ-29D) to entrap positively charged cytochromes made it possible to study the immobilized proteins. When the cytochromes are incorporated into this polymer matrix, diffusion limitations lead to a 50 times lower catalytic efficiency as compared to catalysis with protein in solution. The results of this study demonstrate that only cytochromes with bishistidinyl heme iron coordination act as metal reducers whereas mitochondrial c-type cytochromes do not. This approach opens new pathways for the use of sulfur and sulfate reducing bacteria in the bioremediation of metal contaminated waters and waste streams. Processes involving the use of entrapped enzymes reactors could be developed according to the metal reducing activity of their polyhemic c-type cytochromes.