Quaternizing Agent Research Articles

Microwave Synthesis of Cationic Fatty Imidazolines and their Characterization

AbstractThis paper describes an efficient method for the synthesis of long chain dialkyldiamido imidazolines by the reaction of diethylenetriamine and several fatty acids under non‐solvent microwave irradiation using calcium oxide as support This synthesis required much less time in comparison to conventional thermal condensation and is carried out in an open vessel and the products obtained by this method were found to be in good yields and of high purity. Fatty imidazolines were then quaternized by using dimethyl sulfate as a quaternizing agent and isopropanol as a solvent, to produce cationic imidazolinium salts which were evaluated for yield and cationic content. The instrumental techniques, viz. FT‐IR and 1H NMR verified the formation of imidazolines and its subsequent quaternization. This method produced imidazolines in the very low time of 5–10 min and gave a yield of 89–91% as compared to a very long time of 8–10 h and a lower yield of 75–80% by the conventional thermal condensation method.

Study on the flocculating properties of quaternized carboxymethyl chitosan

Quaternized carboxymethyl chitosan (QCMC) was prepared through the grafting reaction of carboxymethyl chitosan (CMC) with 3-chloro-2-hydroxypropyl trimethylammonium chloride (CTA) as a quaternizing agent in 2-propanol medium under basic condition. The synthetic conditions for QCMC were as follows: 40.0% of NaOH aqueous solution as catalyst; reaction temperature, 60.0 °C and reaction time, 10.0 h; NaOH/CMC, 0.50; CTA/CMC, 1.50 (mass ratio). The characterization by FT-IR and 1H NMR demonstrated that QCMC was a typical amphoteric chitosan derivative in which the carboxymethyl group and the quaternary ammonium group were both introduced into the chitosan molecular chain. QCMC was applied to flocculate a simulated wastewater containing 40.15 mg/L Cd(II) or 15.62 mg/L Cr(VI) respectively. The results indicated that the appropriate pH value for removal of Cd(II) and Cr(VI) were ca 8.5 and 5.0, and the appropriate corresponding mass concentrations of QCMC was 140 mg/L and 120.0 mg/L, respectively. Under these conditions, the removal ratio of Cd(II) and Cr(VI) may reach 99.7% and 94.4%, respectively.

Quaternization of Cotton Stalks and Palm Tree Particles for Removal of Acid Dye from Aqueous Solutions

ABSTRACT Cotton stalks and palm tree were independently grounded, washed thoroughly, and dried at ambient conditions. The cellulose of the obtained products was reacted with diepoxypropyl dimethyl ammonium chloride (III) along with 2-hydroxy-1,3-bis [(epoxypropyl dimethyl ammonium chloride) propane (IV)], thereby giving rise to quaternized products. Compounds III and IV were the resultants of activation with NaOH of a quaternizing agent known commercially as Refaktam K. Quaternization was carried out under different conditions, including material-to-liquor ratio, concentration of the activated Refaktam K, and time and temperature of the reaction. Nitrogen contents of the reaction products were taken as a measure of the extent of the reaction. Also reported was a thorough investigation into the ability of the quaternized products for acid dye adsorption by virture of their cationic nature. The adsorption data obey the Langmuir and Freundlish isotherms. It was further disclosed that the cationic products examined serve as excellent adsorbents for acid dye.

Synthesis of polyurethane cationomers with anil groups: intramolecular proton transfer in salicylideneanil structures

AbstractThree new o‐hydroxy Schiff bases, 2‐chloromethyl‐N‐(2‐hydroxybenzilidene)aniline, 3‐(11‐bromoundecanoyloxymethyl)‐N‐(2‐hydroxybenzilidene)aniline and 4‐chloromethylphenyl (carbamoyloxymethyl‐2‐hydroxybenzylidene)aniline, used as quaternization agents for a polyetherurethane precursor based on poly(tetramethylene oxide) diol of 2000 g mol−1 average molar mass (PTMO), 2,4‐toluene diisocyanate and N‐methyldiethanolamine (1:3:2 molar ratio), have been synthesized in order to obtain polymeric films with fluorescent properties. The structure and the photochromic mechanism of the salicylideneanil units were investigated. The excited state intramolecular proton‐transfer process (ESIPT) with the cis‐ and trans‐keto isomers formation as intermediate compounds and the formation of a keto tautomer were evidenced by a large Stokes shifted emission (100 nm). Copyright © 2005 Society of Chemical Industry

Novel, positively charged membrane from a blending, crosslinking, and coagulation procedure

AbstractA novel, positively charged membrane was prepared through a blending, crosslinking, and coagulation procedure in which poly(N,N‐dimethylaminoethyl methacrylate) (PDM) and polyacrylonitrile (PAN) were used as the functional and substrate component, respectively. Because 1,4‐dibromobutane (DBT) was used as the crosslinker and quaternizing agent, PDM was crosslinked and quaternized simultaneously. The effects of PDM content, polymer concentration, and additive dosage of the casting solution on the membrane performances are discussed in detail, and differences between the PAN membrane, PDM/PAN blend membrane, and crosslinked PDM/PAN blend membrane are also discussed. We also studied the adsorption behaviors of the membranes to a positively charged dye and a negatively charged dye. Environmental scanning electron microscopy observation showed that the resulting positively charged membrane from such a blending, crosslinking, and coagulation procedure possessed a unique and uniform structure. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1847–1854, 2005

Quaternized biomass as an anion exchanger for the removal of nitrate and other anions from water

AbstractDried Chinese Reed (Miscanthus sinensis), a fast growing plant, was used as a model biomass for the development of anion exchangers using a quaternization agent, N‐(3‐chloro‐2‐hydroxypropyl)trimethylammonium chloride (CHMAC), and a cross‐linking agent, epichlorohydrin. Anions studied include nitrate, phosphate, perchlorate and sulfate. Batch mode adsorption studies were conducted using aqueous solutions of anions. Detailed kinetics were studied for nitrate removal. Parameters studied included anion concentration, agitation time, adsorbent dose, and pH. Adsorption equilibrium occurred in 10 min for all the anions studied. Equilibrium adsorption data followed both Langmuir and Freundlich isotherms. The presence of phosphate, perchlorate, fluoride and sulfate lowered the adsorption significantly. The effects of pH on adsorption and desorption show that ion exchange is involved in the adsorption process. The adsorption capacity of the cross‐linked and quaternized Chinese Reed for nitrate, sulfate, phosphate and perchlorate was found to be 7.55, 13.25, 16.61 and 10.07 mg of anion per g of the anion exchanger, respectively. Copyright © 2004 Society of Chemical Industry

An anion exchange resin from soybean hulls

AbstractAgricultural by‐products are generally poor adsorbents of anions in solution. Therefore, modification of the by‐product could enhance its anion exchange capabilities. The objective of this study was to increase the anion exchange properties of the agricultural by‐product, soybean hulls, by chemical modification. Soybean hulls were quaternized with the quaternizing agent, N‐(3‐chloro‐2‐hydroxypropyl) trimethylammonium chloride, in the presence of a strongly alkaline environment. This modification increased the amount of positive charge on the hulls as evidenced by increased nitrogen content and increased uptake of anions compared with the unmodified hulls. A method to optimize the anion exchange properties of the hulls was developed. Ion exchange properties of the hulls toward anions of environmental significance, namely arsenate (As), chromate (Cr), dichromate (Cr2), phosphate (P) and selenate (Se) were determined. The modified hulls were also compared with commercial cellulose‐based and synthetic anion exchange resins in their ability to remove these anions from solution. The experimental and commercial resins were also compared for their ability to remove a mixture of arsenate, chromate, dichromate and selenate from laboratory prepared solutions to levels below the maximum contaminant levels for these anions in drinking water as specified by the US Environmental Protection Agency (US EPA). Our results demonstrate that the soy hull resin is more efficient in anion removal than the commercial cellulose‐based resin but not as effective as the commercial synthetic resin. Published in 2003 for SCI by John Wiley & Sons, Ltd.

Ionic organic/inorganic materials. II. New linear and crosslinked poly(ethylene oxide)‐based ionomers by quaternization with chloroalkyl‐functionalized siloxanes

AbstractSiloxane‐modified cationic polyelectrolytes were synthesized through the quaternization reaction of a poly(ethylene glycol)‐based polymer containing tertiary amine groups in the chain with chloroalkyl‐functionalized siloxanes. Linear or crosslinked structures were obtained, depending on the functionality of the siloxane: a chloroalkyl‐monofunctionalized or ‐polyfunctionalized siloxane was used. The reaction occurred in solution with n‐propanol as a solvent and NaI as a catalyst. All products were characterized with elemental analysis and IR and 1H NMR spectrometry. Viscometric measurements of the linear polymer in dilute aqueous solutions revealed typical polyelectrolyte behavior. The swelling capacities in various solvents of the crosslinked structures were determined. The thermal stability of the crosslinked cationic structures obtained with a polyfunctional siloxane as a quaternization agent was much higher than that of the parent polymer. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3720–3728, 2004

Adsorption of poly(4-vinylpyridine) onto bentonites

The preparation of new adsorbents based on the coating of a poly(4-vinylpyridine) (P 4VP) polymer onto industrial bentonites was investigated. Two ways of synthesis were investigated, using dibromohexane (DBH) or its absence as a difunctional quaternizing agent in order to fasten the polymer by cross-linking. Several parameters (reagents ratio, type of bentonite, chemical stability in liquid media) were studied. Qualitative (IR and RMN spectroscopies) and quantitative (thermogravimetric) analyses of the samples were carried out.

Synthesis of a new cationic surfactant for the alkaline hydrolysis of solvent‐pretreated polyester fabrics

AbstractThe synthesis of a cationic surfactant was based on diethanolamine and alkyl halides such as cetyl bromide with epichlorohydrin as a quaternizing agent. It was characterized by the elemental microanalysis of nitrogen and chloride and infrared spectroscopy. Polyester (PET) crepe fabric was pretreated with a series of solvents, including tetrachloroethane and tetrachloroethylene, at 25, 50, and 100°C. Untreated and solvent‐pretreated PET fabric was hydrolyzed with 8 g/L NaOH at 100°C in the absence and presence of a cationic surfactant as a catalyst, and the weight loss was determined. The effects of solvent pretreatment on alkaline hydrolysis and PET dyeing were also examined. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1652–1660, 2002.

Design and synthesis of some thiazolo[3,2-a]benzimidazole quaternary salts of potential antidiabetic

The present work reports on the synthesis and preliminary pharmacol. investigation of new 3-​aryl-​6,​7-​dimethyl-​9-​substituted thiazolo[3,​2-​a]​benzimidazolium salts. These derivs. were synthesized by reacting the 3-​aryl-​6,​7-​dimethylthiazolo[3,​2-​a]​benzimidazoles with the appropriate quaternizing agent. The latter compds. were, in turn prepd. by cyclodehydration of 5,​6-​dimethyl-​2-​(phenacylthio)​benzimidazoles in polyphosphoric acid (PPA)​. The latter derivs. were obtained by the reaction of 5,​6-​dimethylbenzimidazole-​2-​thione with the appropriate phenacyl bromide. Some of the tested compds. have shown a pronounced hypoglycemic activity. The results do permit the assignment of compds. having N9-​phenacyl entity as promising antidiabetic agents.

ChemInform Abstract: Quaternization of Electron-Deficient Pyridines Containing Two Electron-Withdrawing Substituents.

Methyl triflate is an efficient agent for the quaternization of nitropyridines containing an additional electron-withdrawing substituent. When triethyloxonium hexachloroantimonate is used as the quaternizing agent, β-elimination occurs with formation of protic pyridinium salt and ethylene.

Quaternization of electron-deficient pyridines containing two electron-withdrawing substituents

Methyl triflate is an efficient agent for the quaternization of nitropyridines containing an additional electron-withdrawing substituent. When triethyloxonium hexachloroantimonate is used as the quaternizing agent, β-elimination occurs with formation of protic pyridinium salt and ethylene.

Preparation of anion exchangers from beech sawdust and wheat straw

Beech sawdust, extracted sawdust, wheat straw and extracted straw were quaternized and crosslinked in the presence of sodium hydroxide in one step with 1,3-bis(3-chloro-2-hydroxypropyl)imidazolium hydrogen sulfate or with 3-chloro-2-hydroxypropyltrimethylammonium chloride/epichlorohydrin optionally in the presence of ammonium hydroxide. Under optimal conditions the first system gave much higher yields and amounts of incorporated nitrogen into the water-insoluble residue than the combination of epichlorohydrin and monofunctional quaternizing agent with or without ammonium hydroxide. In the absence of ammonium hydroxide, slightly better results were obtained. There is a correlation between nitrogen content and exchange capacity of anion exchangers as determined by elemental analysis after recycling with sodium hydroxide, hydrochloric, sulfuric or phosphoric acid. When wheat straw was modified, slightly better results were obtained than on beech sawdust although both materials are suitable for this application.

Synthesis and properties of liquid-crystalline polyetherurethane cationomers

Two series of polyetherurethanes (PEU) were prepared from poly(tetramethylene oxide) (PTMO, M n = 1000) as a soft segment and varying concentrations of hard segments based on 1 ,6-diisocyanohexane (HDI), and 2,2'-methyliminodiethanol (MDEA). The liquid-crystalline PEU cationomers (LC-PEUCs) were synthesized by quaternization of the tertiary amine of MDEA using liquid-crystalline mesogenic quaternizing agents (LCMQAs). The LCMQAs consisting of a rigid mesogenic azobenzene moiety and biphenyl attached to alkyl bromide as a spacer were synthesized. The quaternization and molecular structure of LC-PEUCs were ascertained by FT-IR and 'H-NMR spectroscopy. The effects of LCMQAs and degree of quaternization on the liquid-crystalline behavior, the extent of phase separation. and physical properties were studied by differential scanning calorimetry (DSC), a polarizing microscope equipped with a heating stage, dynamic mechanical analysis (DMA), and tensile testing. All of the LCMQAs exhibited a nematic phase and a smectic mesophase was found for all synthesized LC-PEUCs.

Synthesis and properties of liquid-crystalline polyetherurethane cationomers

Two series of polyetherurethanes (PEU) were prepared from poly(tetramethylene oxide) (PTMO, Mn= 1000) as a soft segment and varying concentrations of hard segments based on 1,6-diisocyanohexane (HDI), and 2,2′-methyliminodiethanol (MDEA). The liquid-crystalline PEU cationomers (LC-PEUCs) were synthesized by quaternization of the tertiary amine of MDEA using liquid-crystalline mesogenic quaternizing agents (LCMQAs). The LCMQAs consisting of a rigid mesogenic azobenzene moiety and biphenyl attached to alkyl bromide as a spacer were synthesized. The quaternization and molecular structure of LC-PEUCs were ascertained by FT-IR and 1H-NMR spectroscopy. The effects of LCMQAs and degree of quaternization on the liquid-crystalline behavior, the extent of phase separation, and physical properties were studied by differential scanning calorimetry (DSC), a polarizing microscope equipped with a heating stage, dynamic mechanical analysis (DMA), and tensile testing. All of the LCMQAs exhibited a nematic phase and a smectic mesophase was found for all synthesized LC-PEUCs.

5627246 Supported metallocene complexes having heterofunctional groups in the cyclopentadienyl system as catalyst systems

A supported catalyst system that is obtained by a) reacting a finely divided carrier with an a-trisalkoxy-silyl-ω-haloalkyl compound, b) adding a metallocene complex of the indicated formula I to the reaction product of a); c) reacting the product of b) with a quaternizing agent; and d) optionally adding an open-chain or cyclic alumoxane compound. The catalyst system can be used to prepare polymers of C 2 -C 10 -alk-1-enes.

Synthesis and characterization of polypyrrolepolyurethane cationomer composites

AbstractPoly(ether urethane) cationomers based on poly(oxytetramethylene), 4,4′‐bibenzyldiisocyanate, N‐methyldiethanolamine as chain extender, and acrylic acid/poly(acrylic acid) as quaternization agent were synthesized. Pyrrole (15 wt.%%) was polymerized in films of the ionomer containing CuCl2. The films were characterized by dynamic mechanical analysis, thermogravimetry and differential scanning calorimetry. The electric conductivity of the film without polypyrrole is 7.5 · 10−12 Ω−1 cm−1, while incorporation of polypyrrole increases the conductivity to 4.5 · 10−6 Ω−1 cm−1.

Influence of the functionality of the quaternizing agent and the polymer molecular weight on the viscoelastic behaviour of α,ω-(dimethylamino)polyisoprenes

Quaternization of the end-groups of α,ω-(dimethylamino)polyisoprenes with monofunctional, difunctional and trifunctional halides (iodides and bromides) has been undertaken on polymers of different molecular weights ( M n =6000 and 38000 g mol −1 ). The thermal stability of the ammonium end-groups is somewhat better when iodide counteranions are present. Quaternization increases the T g of the material. This effect is more pronounced for low molecular weight chains, especially when a short alkyl group quaternizing agent is used. However, the size of the alkyl or aryl radical has a minor effect on polymer T g when difunctional quaternizing agents are used. Nevertheless, the modulus of the rubber-like plateau of materials with difunctional agents is higher than with monofunctional quaternizing agents, owing to coupling reactions between the chain-ends. Rheological measurements indicate that the quaternized low molecular weight polyisoprenes exhibit an Arrhenius-type temperature dependence characterized by activation energies which vary between 121 and 146 kJ mol −1 and suggest that the relaxations attributed to dipole—dipole interactions dominate over long chain entanglements.

Phase inversion and its effect on the properties of polyester polyurethane cationomers

Polyester polyurethane cationomers are prepared using polyester polyol of molecular weight 2000 as soft segments, N-methyl diethanolamine as chain extender, glycolic acid as quaternization agent, methyl ethyl ketone as solvent, and 4,4'-diphenylenemethylene diisocyanate (MDI) as diisocyanate. Properties of the films cast from solutions and emulsions are studied by infrared spectroscopy, dynamic mechanical analysis, thermogravimetric analysis, differential scanning calorimetry, and tensile-elongation testing. Ionization can cause phase separation and produces increased cohesion in the hard domains. The dispersion process can be divided into three stages involving a separation of hard segment aggregates due to adsorption of water on their surface, water entering into hard segment microionic lattics, and finally a rearrangement of agglomerates to form microspheres. The dispersion can disrupt the order in the hard domains and an increased phase separation.