Quaternary Ammonium Chloride Salts Research Articles

Electrodeposition of Al-Cr-Mn Alloys from Chloroaluminate Ionic Liquids

Despite the emergence of many new ionic liquid systems or room-temperature molten salts, chloroaluminate ionic liquids are still one of the most versatile systems for the electrochemical surface finishing of metals. The most commonly studied chloroaluminate IL is the well-known mixture of AlCl3 and the quaternary ammonium chloride salt, 1-ethyl-3-methylimidazolium chloride (EtMeImCl).1 Among the anhydrous, aprotic ILs prepared to date, this mixture still holds the record for the highest conductivity and lowest viscosity. Save for the need to protect it from exposure to moisture, it is undoubtedly one of the most versatile IL systems for electrochemistry. In most cases, the acidic composition of this IL proves to be the most valuable composition for surface finishing, owing to the presence of the coordinately unsaturated Lewis acidic species, Al2Cl7 -, which is readily reduced to Al metal via the reaction:4Al2Cl7 - + 3e- ⇌ Al + 7AlCl4 - (1)The electroplating of Al from chloroaluminate ILs, such as AlCl3-EtMeImCl, is one of the most thoroughly studied processes in the field of ionic liquid electrochemistry, as attested in a recent review.2 However, much less attention has been devoted to the electrodeposition of aluminum alloys from these ILs, many of which have very useful properties. Stable alloys can be obtained during the electrodeposition of Al if certain low valent transition metal ions, M z +, that are reduced negative of the potential required for the reaction shown in Eq. 1 are added to the acidic IL, e.g., Cr2+, Ti2+, V2+, Mo2+, and Mn2+, to name a few.2 In this case, it is possible to prepare aluminum-transition metal alloys: xM(AlCl4) p (p-z)- + 4(1-x)Al2Cl7 - + [3-(3-z)x]e- ⇌ M x Al1-x + [7(1-x) +px]AlCl4 - (2)where x represents the fraction of the transition metal in the M x Al1-x alloy. For some values of x, these so-called “overpotential alloys” form single-phase metallic glasses. In this case, these amorphous, non-equilibrium alloys exhibit a greatly enhanced resistance to chloride pitting corrosion relative to pure Al. Ternary alloys with metallic glass phases can also be produced by adding a second transition metal to the acidic IL. Articles have appeared in The Journal describing the electrodeposition and properties of such aluminum alloys containing Mn + Mo,3 Mo + Ti,4 and Mn + W.5 In general, coatings prepared with ternary alloys display enhanced resistance to chloride pitting corrosion compared to the corresponding binary alloys. In this poster, we describe recent work on the electrodeposition of Al-Cr-Mn ternary alloys.

(Invited) Surface Finishing with Chloroaluminate Ionic Liquids

Despite the emergence of many new ionic liquid systems or room-temperature molten salts, chloroaluminate ionic liquids are still one of the most versatile systems for the electrochemical surface finishing of metals, whether it be the electrodeposition of corrosion protective films on steel or the electrochemical polishing of metal surfaces, such as Cu. The most commonly studied chloroaluminate IL is the well-known mixture of AlCl3 and the quaternary ammonium chloride salt, 1-ethyl-3-methylimidazolium chloride (EtMeImCl).1 Among the anhydrous, aprotic ILs prepared to date, this mixture still holds the record for the highest conductivity and lowest viscosity. Save for the need to protect it from exposure to moisture, it is undoubtedly one of the most versatile IL systems for electrochemistry. In most cases, the acidic composition of this IL proves to be the most valuable composition for surface finishing, owing to the presence of the coordinately unsaturated Lewis acidic species, Al2Cl7 -, which is readily reduced to Al metal via the reaction: 4Al2Cl7 -+3e- ⇌Al + 7AlCl4 - (1) The electroplating of Al from chloroaluminate ILs, such as AlCl3-EtMeImCl, is one of the most thoroughly studied processes in the field of ionic liquid electrochemistry, as attested in a recent review.2 However, much less attention has been devoted to the electrodeposition of aluminum alloys from these ILs, many of which have very useful properties. Stable alloys can be obtained during the electrodeposition of Al if certain low valent transition metal ions, Mz+, that are reduced negative of the potential required for the reaction shown in eq 1 are added to the acidic IL, e.g., Ti2+, V2+, Mo2+, and Mn2+, to name a few.2 In this case, it is possible to prepare aluminum-transition metal alloys: xM(AlCl4) p (p-z)- + 4(1-x)Al2Cl7 - + [3-(3-z)x]e- ⇌M x Al1-x + [7(1-x) +px]AlCl4 - (2) where x represents the fraction of the transition metal in the M x Al1-x alloy. For some values of x, these so-called “overpotential alloys” form single-phase metallic glasses. In this case, these amorphous, non-equilibrium alloys exhibit a greatly enhanced resistance to chloride pitting corrosion relative to pure Al. Ternary alloys with metallic glass phases can also be produced by adding a second transition metal to the acidic IL. Articles have appeared in The Journal describing the electrodeposition and properties of such aluminum alloys containing Mo + M, Mo + Ti, and W + Mn. Recently, both the Lewis acidic and basic composition of the AlCl3-EtMeImCl IL system have been explored for the reverse purpose, the electropolishing of Al and Cu by anodic dissolution. The advantages afforded by anodic dissolution in these ILs relative the aqueous acids and salt solutions commonly used for this purpose are quite obvious, i.e., the avoidance of the oxide surface films that invariably complicate the electropolishing process. In this paper, we report recent advances in the electrodeposition of aluminum transition metal alloys for metal surface finishing as well as the thermodynamics and kinetics of the anodic dissolution of metals in the acidic and basic compositions of the AlCl3-EtMeImCl IL system.

Design of experiments to evaluate clay swelling inhibition by different combinations of organic compounds and inorganic salts for application in water base drilling fluids

In this study the synergistic behavior that occurs when three different cationic inhibitors for clay swelling were associated with brines containing NaCl and KCl was evaluated. These commercial inhibitors are based on a cationic quaternary polyamine chloride with quaternary ammonium group (INIB 1), on a cationic polyacrylamide chloride with quaternary ammonium group (INIB 2) and on a quaternary ammonium chloride salt (INIB 3). Each inhibitor was characterized considering the amount of chlorides and content of active matter. The tests were performed with a commercial bentonite. Capillary suction timer (CST) and linear swell meter (LSM) were used for the evaluation of clay–water interaction in the presence of various fluids. For a better interpretation of the experimental results statistical analysis (DOE — design of experiments) via response surface methodology (RSM) was used, taking into account the type and concentration of inhibitors, the type and concentration of brines as well as the contact time of the inhibitor solutions with clay. The results showed different efficiencies, in other words, inhibitors mixed with brines were more effective than the inhibitors alone. The best results were obtained for cationic polyacrylamide chloride with quaternary ammonium group at 7lb/bbl (pounds per barrel) in KCl brine at 18.74lb/bbl with contact time of brine and clay of 7.6h. Solutions containing these combinations presented greater inhibition of clay swelling. However, for field operations, other parameters should be considered as operating cost, environmental requirements and the application time of each product.

Corrosion Resistance of Aluminum Films Electroplated on Steel from Chloroaluminate Ionic Liquids Containing Toluene as a Co-Solvent

Aluminum is a widely used material for corrosion resistant coatings. From a thermodynamic perspective, it is a very active metal. However, its excellent corrosion resistance stems from the formation of a robust, self-healing ~50 nm thick barrier film of Al2O3, which is formed spontaneously upon exposure to air at ambient temperature. Unfortunately, it is established that aluminum cannot be plated from aqueous solutions under normal conditions because hydrogen is evolved before most Al(III) species are reduced to Al. A number of commercial Al plating processes have been developed. Typically, these processes are based on pyrophoric mixtures of AlCl3 or AlBr3 with LiAlH4 dissolved in suitable organic solvents, such as ethers or mixtures of substituted benzenes.The first report in which a room-temperature haloaluminate ionic liquid was used to plate Al appeared in 1948.1 Although moisture-sensitive themselves, such ionic liquids, particularly those based on mixtures of AlCl3 and quaternary ammonium chloride salts, have many safety and convenience advantages over the currently used commercial Al plating baths. In this work, we report the pulsed-current plating of Al on steel substrates from the Lewis acidic AlCl3-1-ethyl-3-methylimidazolium chloride (EtMeImCl) ionic liquid with and without organic co-solvents. Compared to DC methods, pulsed-current techniques can produce electrodeposited metals with smaller grain size and greater brightness, as well as less internal stress and correspondingly greater corrosion resistance.Some preliminary results for Al films electrodeposited on steel from this ionic liquid are shown in Figs. 1 and 2. The surface morphology and corrosion resistance of these films were interrogated with optical microscopy and electrochemical impedance spectroscopy (EIS) in aqueous NaCl, respectively. Micrographs of typical Al electrodeposits (Fig. 1) indicate that their surface morphologies changed significantly with changes in t on and t off. For example, the grain size of the Al film prepared with t on = 0.25 s is much smaller than that for deposits prepared with t on =1 s. Figure 2 shows complex plane impedance plots resulting from EIS experiments. These plots show at least one time constant. A circuit model for an electrode coated with an inert porous layer2 was fitted to the data in Fig. 2 to extract information about the pore resistance (R p) of the coating. The pore resistance reflects the corrosion resistance of the electrodeposited films. Figure 2 shows that the best results were obtained for t on = 0.25 s and t off = 0.50 s in agreement with the results obtained by microscopy. It was generally found that films with the best corrosion resistance were obtained with smaller values of t on. Optimization of the parameters for the pulse plating of Al will be discussed with respect to the surface structure, grain size, corrosion resistance, and brightness of the deposits. References 1F. H. Hurley, U.S. Pat. 2,446,331 (1948). 2M. E. Orazem and B. Tribollet, Electrochemical Impedance Spectroscopy, (New Jersey: John Wiley and Sons, 2008). Acknowledgement This work was funded by the Strategic Environmental research and Development Program (SERDP) through contract DE-AC05-00OR22725 to Oak Ridge National Laboratory.

Alcohol Cosurfactants in Hydrate Antiagglomeration

Because of availability, as well as economical and environmental considerations, natural gas is projected to be the premium fuel of the 21st century. Natural gas production involves risk of the shut down of onshore and offshore operations because of blockage from hydrates formed from coproduced water and hydrate-forming species in natural gas. Industry practice has been usage of thermodynamic inhibitors such as alcohols often in significant amounts, which have undesirable environmental and safety impacts. Thermodynamic inhibitors affect bulk-phase properties and inhibit hydrate formation. An alternative is changing surface properties through usage of polymers and surfactants, effective at 0.5 to 3 weight % of coproduced water. One group of low dosage hydrate inhibitors (LDHI) are kinetic inhibitors, which affect nucleation rate and growth. A second group of LDHI are antiagglomerants, which prevent agglomeration of small hydrate crystallites. Despite great potential, work on hydrate antiagglomeration is very limited. This work centers on the effect of small amounts of alcohol cosurfactant in mixtures of two vastly different antiagglomerants. We use a model oil, water, and tetrahydrofuran as a hydrate-forming species. Results show that alcohol cosurfactants may help with antiagglomeration when traditional antiagglomerants alone are ineffective. Specifically, as low as 0.5 wt. % methanol cosurfactant used in this study is shown to be effective in antiagglomeration. Without the cosurfactant there will be agglomeration independent of the AA concentration. To our knowledge, this is the first report of alcohol cosurfactants in hydrate antiagglomerants. It is also shown that a rhamnolipid biosurfactant is effective down to only 0.5 wt. % in such mixtures, yet a quaternary ammonium chloride salt, i. e., quat, results in hydrate slurries down to 0.01 wt. %. However, biochemical surfactants are less toxic and biodegradable, and thus their use may prove beneficial even if at concentrations higher than chemical surfactants.

Rapid Fixation of Methylene Chloride by a Macrocyclic Amine

A simple macrocyclic amine is alkylated by methylene chloride to give a quaternary ammonium chloride salt. When methylene chloride is the solvent, the reaction exhibits pseudo-first-order kinetics, and the reaction half-life at 25.0 degrees C is 2.0 min. The reaction half-life for a structurally related, acyclic amine is approximately 50 000 times longer. Detailed calculations favor a mechanism where the methylene chloride associates with the macrocycle to form an activated prereaction complex. The macrocyclic nitrogen subsequently attacks the methylene chloride with a classic SN2 trajectory, and although the carbon-chlorine bond breaks, the chloride leaving group does not separate from the newly formed cationic macrocycle, such that the product is a tightly associated ion-pair. X-ray crystal structures of the starting amine and the product salt, as well as kinetic data, support this mechanism.

Effect of carrier type on coupled transport kinetics of thiocyanate ions through liquid membranes

Coupled transport of thiocyanate ions through a liquid membrane containing quaternary ammonium chloride salts in chloroform was examined. The influences of the carrier type in the membrane phase on the coupled transport of thiocyanate ions were investigated. The kinetics of the coupled transport were analyzed in the formalism of two consecutive irreversible first-order reactions and the kinetic parameters ( k 1 d , k 2 m , k 2 a , R m max, t max, J d max, J a max) were also calculated. For the coupled transport of thiocyanate ions, quaternary ammonium chloride salts having different carbon atom numbers ( C n ) used as carriers were found to increase thiocyanate ions transport efficiency with increasing carbon atom numbers. Tetradecyl trimethylammonium chloride (TDTMACl), hexadecyl trimethylammonium chloride (HDTMACl), and tetraoctyl ammonium chloride (TOACl) were found to be the most effective carrier types for transport of thiocyanate ions when C n is greater than 16. The activation energies for maximum membrane entrance and exit fluxes were calculated as 32.45 kJ/mol and 34.75 kJ/mol, respectively. The values of the activation energy indicate that the process is controlled by species diffusion.

Purification of heterocyclic drug derivatives from concentrated saline solution by nanofiltration

We purified by nanofiltration a highly concentrated (11–17% w/v) mixture of organic/inorganic salts, generated from pharmaceutical industries to separate mineral salts (sodium acetate and sodium chloride) from heteroaromatic quaternary ammonium chloride salts soluble in water. The process, using a spiral-wound nanofiltration module, consists of a diafiltration step until the minerals salts were almost completely eliminated followed by a concentration step. To optimise the process, three variables were studied: transmembrane pressure (TMP), velocity, pH. The retention of organic salts was higher than 99.5%. The higher the molecular weight, the higher the retention factor. The flux and rejection show that it is not necessary to increase transmembrane pressure to obtain the faster salt elimination. The best result is obtained with the highest velocity which reduces membrane fouling. Changing pH from 3 to 4.5 had little effect on permeate flow; however, the purification of a solution at pH 5.4 is difficult because of a very low permeate flow. Less than 2% of the ammonium salts entrapped in the membrane were lost. Under optimal experimental conditions, more than 99% of mineral salts can be eliminated.

Synthesis of poly[(2-oxo-1,3-dioxolan-4-yl)methyl vinyl ether-co-N-phenylmaleimide] and its miscibility in blends with styrene-acrylonitrile or poly(vinyl chloride)

The aim of the study was to investigate the synthesis of a copolymer bearing cyclic carbonate and its miscibility with styrene/acrylonitrile copolymer (SAN) or poly(vinyl chloride) (PVC). (2-Oxo-1,3-dioxolan-4-yl)methyl vinyl ether (OVE) as a monomer was synthesized from glycidyl vinyl ether and CO2 using quaternary ammonium chloride salts as catalysts. The highest reaction rate was observed when tetraoctylammonium chloride (TOAC) was used as a catalyst. Even at the atmospheric pressure of CO2, the yield of OVE using TOAC was above 80% after 6 h of reaction at 80°C. The copolymer of OVE and N-phenylmaleimide (NPM) was prepared by radical copolymerization and was characterized by FTIR and 1H-NMR spectroscopies and differential scanning calorimetry (DSC). The monomer reactivity ratios were given as r1 (OVE) = 0.53–0.57 and r2 (NPM) = 2.23–2.24 in the copolymerization of OVE and NPM. The films of poly(OVE-co-NPM)/SAN and poly(OVE-co-NPM)/PVC blends were cast from N-dimethylformamide. An optical clarity test and DSC analysis showed that poly(OVE-co-NPM)/SAN and poly(OVE-co-NPM)/PVC blends were both miscible over the whole composition range. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1809–1815, 2000

Synthesis and characterization of copper containing mesoporous silicas

A series of copper containing mesoporous silicas has been prepared at room temperature using tetramethylorthosilicate as the source of silicon, a quaternary ammonium chloride salt as organic template surfactant and copper complexes obtained from organofunctional silicon molecules as ligands. Using this synthetic route, it was possible to prepare mesoporous materials containing up to 4.7 wt% copper. The structure and the sorption properties of the obtained materials have been studied by X-ray diffraction, Fourier-transform reflectance IR spectroscopy, transmission electron microscopy and surface area measurements. All experimental data reveal that calcined products containing up to 2.4 wt% copper retain the basic structural characteristics of MCM-41 materials, while higher copper loading leads to progressive destruction of hexagonal structure. Electron paramagnetic resonance was used to study the symmetry and environment of Cu(II) species in the silicate framework of the as synthesized and calcined materials, as well as the accessibility of these centers to polar adsorbed molecules, such as pyridine. The spectra of calcined materials indicate a distorted octahedral geometry for the Cu(II) centers which were easily accessible by pyridine molecules. Cyclic voltammetry showed that calcined copper containing mesoporous samples exhibit a marked electroactivity indicating that most of the copper centers are distributed on the mesoporous surfaces.

Process development for electrocarboxylationof 2-acetyl-6-methoxynaphthalene

Electrochemical carboxylation of 2-acetyl-6-methoxynaphthalene to 2-hydroxy-2-(6-methoxy-2-naphthyl)propionic acid may be carried out in good yield (∼89% in the electrolysis; 75% as isolated dried product) in an undivided flow cell using lead as the cathode and aluminium as the dissolving anode. Dimethylformamide was found to be the best solvent for the reaction and low cost tetraethylammonium chloride hydrate is a good electrolyte for the system. The best conditions are those that increase carbon dioxide concentration although higher pressure seems to be more effective than low temperature. The reaction may be carried out with good yield at fairly high current density (1150Am−1) and higher current densities are likely attainable. The allowable payload is limited to around 10% because higher payloads (20%) resulted in solution too viscous to pump. Initially it was surmised that trace quantities of water would be detrimental to good yields in these reactions. However, it was found that small amounts of water (that associated with typical quaternary ammonium chloride salts) has the beneficial effect of eliminating the major byproduct which is formed in more nearly anhydrous solutions without resulting in formation of alternative byproducts. Process conditions were evaluated at 0.2L scale, then scaled up to 1L and finally 75L. The best results were attained in the 1L system, solvable operating problems limited the yield in the largest scale electrolysis.

Final Report on the Safety Assessment of Quaternium-18, Quaternium-18 Hectorite, and Quaternium-18 Bentonite

Quaternium-18 is a mixture of quaternary ammonium chloride salts. Quaternium-18 Hectorite and Bentonite are the reaction products of Quaternium-18 with clays. These compounds are poorly absorbed through the skin. Acute oral and percutaneous toxicity tests in animals indicate that they exhibit little or no systemic toxic effects. Subchronic oral and dermal toxicity tests on Quaternium-18 and Quaternium-18 Bentonite present no evidence of systemic toxicity. These compounds are only slightly irritating to the animal skin, and are not sensitizing agents. In ocular irritation studies all three compounds have been shown to be at most mild irritants. Quaternium-18 has been found to be practically nonirritating and nonsen-sitizing to human skin. Quaternium-18 Hectorite is classified as a nonirritating, and nonsensitizing agent. It does not present adverse phototoxic or photo-allergenic effects. Quaternium-18 Bentonite is not an irritating or sensitizing agent to the human skin and does not induce ocular irritation in humans. On the basis of the available information, it is concluded that Quaternium-18, Quaternium-18 Hectorite, and Quaternium-18 Bentonite are safe as cosmetic ingredients in the present practices of use and concentration.

Determination of the structure and composition of clinically important polyurethanes by mass spectrometric techniques

AbstractCurie‐point pyrolysis mass spectrometry (Py‐MS) and direct probe pyrolysis high resolution mass spectrometry (Py‐HRMS) were used to identify the components and additives used in the synthesis and compounding of Biomer, Lycra Spandex, Tecoflex, and Pellethane. Two types of Biomer were identified (P and Q, our notation) which are composed of poly(tetramethylene glycol) (PTMG) capped with 4,4′‐methylenebis(phenylisocyanate) (MDI) and chain‐extended with ethylenediamine (EDA). Both forms contain 4,4′‐butylidene‐bis‐(6‐t‐butyl‐m‐cresol) antioxidant, and Biomer Q also contains an additive which appears to be a quaternary ammonium chloride salt. Lycra Spandex was found to be identical to Biomer Q, with the exception that a low molecular weight polydimethylsiloxane oil is also present. This silicone oil can be removed by solvent extraction. Tecoflex (type SG80A) is composed of PTMG capped with 4,4′‐diisocyanatodicyclohexylmethane and extended with 1,4‐butanediol (BD). An industrial grade and a medical grade of Pellethane were analyzed. Both were composed of PTMG capped with MDI and extended with 1,4‐butanediol. the industrial grade also contains an antioxidant, possibly butylated diphenylamine.

Extraction of zinc chloride from aqueous chloride solutions by hydrocarbon solutions of quaternary ammonium chloride salt Attempt to evaluate the zinc chloride complexes by means of the extraction data

The extraction of zinc chloride from aqueous chloride solutions has been studied as a function of the supporting LiCl electrolyte concentration. The extraction of zinc ions has been described as the distribution of the electrolyte ZnCl 2+ p Li p between two phases. The coextraction of LiCl in the organic phase has been considered also. An attempt has been made to evaluate the zinc-chloride complexes as a function of the LiCl concentrations by using the activity functions a − Cl = m − Cl · γ − ± LiCl and a Cl = m Licl · γ ± LiCl to account for the dependence of the organic chloride activity of the aqueous ligand activity on the aqueous LiCl concentration. Despite the approximations included in the use of the activity functions and other assumptions made, the parameters obtained reasonably agree with the literature data.