Amount Of Quaternary Ammonium Salt Research Articles

Revealing the AcOH-Induced Dissolution Mechanism of Alcohol-Soluble Interlayers.

Water/alcohol-soluble cathode interlayers are widely utilized in organic electronic devices. However, the mechanism by which acetic acid (AcOH) facilitates the solubility of neutral cathode interlayers in water/alcohol remains unclear. This paper focuses on the AcOH-induced dissolution mechanism of neutral cathode interlayer materials and establishes quantitative relationships for chemical reactions. It was found that AcOH could react acid-base with the amino groups of PFN or PDIN, resulting in the formation of trace amounts of quaternary ammonium salts, which ultimately enhance the solubility of PFN and PDIN in methanol. Additionally, this study clarifies the debate about the role of neutral cathode interlayers in organic electronic devices: It is primarily the unprotonated groups of water/alcohol-soluble cathode interlayers that play a critical role in interfacial modification rather than the protonated groups produced by postacid reaction, which lays an important theoretical foundation for the development of high-performance interfacial materials.

Palladium‐Catalyzed Direct C−H Arylation of Arenes Promoted by Quaternary Ammonium Salt

AbstractA new Pd‐based catalytic system for the direct C−H arylation of arenes was developed. The use of a substoichiometric amount of quaternary ammonium salt as an additive with a Pd source achieved the direct arylation of unactivated arenes under milder reaction conditions in moderate to high yields. The ammonium salt generates the anionic palladium complex, thereby facilitating arylation by a concerted metalation‐deprotonation process.

XRD Study of Hydrophlogopite Intercalated with Alkyl Quaternary Ammonium Salt

Hydrophlogopite was modified with sodium and then organically intercalated with a series of alkyl quaternary ammonium salts. The organically intercalated samples were characterized by X-ray diffraction analysis (XRD) and the effect of alkyl quaternary ammonium salt on the interlayer spacing of hydrophlogopite was discussed. The results showed that if the same alkyl quaternary ammonium salt was used to intercalate hydrophlogopite, the interlayer spacing of hydrophlogopite increased gradually with the rise of the added amount of quaternary ammonium salt, and that if different quaternary ammonium salts with the same amount were used, the interlayer spacing increased gradually with the rise of the chain length of the alkyl quaternary ammonium salts. For the alkyl quaternary ammonium salts with large chain length (n>10), the inflection point for the increasing interlayer spacing of the intercalated hydrophlogopite is at about 0.5 times of CEC. When octadecyl trimethyl ammonium bromide is used as intercalation agent and the added amount is 5 times of CEC, the interlayer spacing of hydrophlogopite is relatively maximal.

Mixed ternary ion associate formation between xanthene dye, cinchona-alkaloid and quaternary ammonium ion and its application to the determination of trace amounts of quaternary ammonium salts in pharmaceuticals

Xanthene dyes such as eosin and tetraiodofluorescein form 1:2 ion associates with quaternary ammonium ions at pH 7–9; however, the development of color in the organic solvent is poor. When a quaternary ammonium salt is added in the extractable 1:2 associate formed between a xanthene dye and a cinchona-alkaloid in the neutral media, a mixed ternary ion associate (xanthene dye:cinchona-alkaloid:quaternary ammonium ion=1:1:1) is formed. Its extractability is enhanced due to the more bulky associate formation. The ion association caused by addition of cinchona-alkaloids is unique. Of the cinchona-alkaloids, quinidine and cinchonidine with tetraiodofluorescein show excellent effects on sensitivity and extractability. Eosin and tetraiodofluorescein are useful as ion association reagents in the ion associate formation. The apparent molar absorptivities are about 1×10 5 l mol −1 cm −1 and the calibration range for quaternary ammonium salt is from 2.5×10 −7 to 1.5×10 −6 M. The proposed method is applicable to the selective and sensitive determination of cetylpyridinium chloride, berberine chloride and benzethonium chloride in pharmaceuticals.

Biaryl synthesis via Suzuki coupling promoted by catalytic amounts of quaternary ammonium salts

Palladium-catalyzed Suzuki cross-coupling reaction (between phenylboronic acid and 4-bromobenzonitrile) in presence of catalytic quaternary ammonium salts is described. With Aliquat 336 (tricaprilylmethylammonium chloride), the rates of the reaction were increased in DME and toluene allowing to work with lower stirring and at lower temperatures in some cases.

Titanium(IV) chloride and quaternary ammonium salt promoted Baylis-Hillman reaction.

The Baylis-Hillman reaction of aldehydes with alpha,beta-unsaturated ketones can be drastically affected by the reaction temperature and Lewis bases. When the reaction was carried out at -78 degrees C using catalytic amounts of quaternary ammonium salts (R4N+X-, X = Cl, Br, I) as Lewis bases, in the presence of titanium(IV) chloride, the chlorinated aldol adduct 1 was obtained as the major product. Quaternary ammonium bromides and iodides (R4N+X-, X = Br, I) have higher catalytic activity than corresponding chlorides (R4N+Cl-). Quaternary ammonium fluorides (R4N+F-) do not have activity at all. The amounts of Lewis acid and quaternary ammonium salts used affect the reaction rate and product. A plausible reaction mechanism is proposed. If the reaction was carried out at room temperature (about 20 degrees C) in the presence of titanium(IV) chloride and quaternary ammonium salts (R4N+X-, X = Cl, Br, I), the elimination product 3, derived from 1, was formed as the major product.

Synergetic Effect of Two Kinds of Phase Transfer Catalysts in Third Phase for Dehydrohalogenation of 2-Bromooctane.

Dehydrohalogenation of 2-bromooctane in the organic phase with dodecane solvent by using phase transfer catalysts (PTC) was carried out in a batch reactor with potassium hydroxide solvent in the aqueous phase. A synergetic effect of PTC was observed for the combination of tetrahexyl ammonium bromide ((Hex)4NBr) and polyethylene glycols (PEG) in the third phase. The observed reaction rate constant (kobs), which is determined from the first order kinetics, depends on the average molecular weight of PEG, and remarkably increases with the increasing KOH concentration in the aqueous phase. If the optimum combination of (Hex)4NBr and PEG with average molecular weight of 200 (PEG200) is used, the amount of quaternary ammonium salt can be significantly saved (for example, by one-nineteenth).The volume of the third phase and the concentration of water in the third phase (CH2O) were measured and related to the reaction rate constant as well as the distribution coefficient (KA).Catalysts which exist in the third phase can be reused without any loss of catalytic activity.

Synthesis of perfluoro-(1,1-dimethylbutyl)methyl ethers by vic-oxymethylfluorination of perfluoro-2-methyl-2-pentene with chloromethyl ethers

Perfluoro-2-methyl-2-pentene was successfully converted to perfluoro-(1,1-dimethylbutyl)methyl ethers by vic-oxymethylfluorination with chloromethyl ethers in the presence of KF in aprotic polar solvents such as N,N-dimethylformamide and N-methylpyrrolidone. By the addition of a catalytic amount of quaternary ammonium salt, the reaction was accelerated and the yield of product greatly increased.

Kinetics of Synthesizing Dibutanoxymethane at Very High Alkaline Concentration by Phase Transfer Catalysis

AbstractThe reaction of dibromomethane and 1‐butanol to synthesize dibutanoxymethane in a very high alkaline concentration of KOH (i.e. large amount of solid KOH/organic solvent) by phase transfer catalysis was studied. Only one unique final product with two butanoxide substituents was observed in the organic phase, thus indicating a very fast rate for the second reaction. The reaction rate was significantly enhanced by adding a small amount of quaternary ammonium salt. Only a pseudo‐first‐order rate law can be applied to describe the reaction at a very high concentration of KOH. This peculiar phenomenon was explained by the limitation of the chemical reaction equilibrium in the aqueous phase as the controlling step at a low KOH concentration, and the reaction in the organic phase as the controlling step at a high KOH concentration. The experimental results indicate that the mass‐transfer resistance of the active catalyst ((C4H9)4N+ ‐OC4H9; QOR) is negligible, compared with the reactions in the two phases. When using TBAB as the catalyst, the only way to increase the product yield is by the use of a solvent with appropriate polarity and a small amount of water at a very high alkaline KOH content.

Synthesis of Formaldehyde Acetals by Phase Transfer Catalysis

Abstract By employing phase transfer catalysis, formaldehyde acetals were synthesized from the reaction of alcohols and dibromomethane at moderate temperatures. Using a high alkaline concentration, the reaction could be improved to obtain a 100% yield by reacting dibromomethane and 1-alcohol employing tetrabutylammonium bromide (TBAB) as a phase transfer catalyst. Six kinds of alcohols with various structures, four sorts of solvents with various dielectric constants and seven types of catalysts were examined to test their reactivities to the reactions. Only one unique product with two alkoxides substituents was observed which indicated the presence of a rather fast reaction rate during the second reaction of the organic phase. The reaction was dramatically enhanced by adding a small amount of quaternary ammonium salt (QX) to obtain a 100% yield utilizing the alcohols with nonbonding electron pairs within a short period of reaction time. The conversion was also observed to be strongly dependent upon the structure of the quaternary ammonium salts. The reaction rate and the product yield were satisfactorily accounted for the chemical reaction equilibrium of alcohols and KOH in the aqueous phase, the hydration of the active catalyst (QOR) in the organic phase and the distribution of QOR between two phases.

ChemInform Abstract: Polymer‐Supported Reagents. Part 4. Oxidation of Alcohols by Complex Chromates, Soluble Models and Supported Species.

AbstractThe oxidation of alcohols with chromium trioxide in the presence of stoichiometric or catalytic amounts of quaternary ammonium salts is described.

Synthesis of N,N?-dialkylquinacridones under the conditions of heterogeneous catalysis

Alkylation of quinacridone in a heterogeneous medium in the presence of catalytic amounts of quaternary ammonium salts; was used to synthesize N,N′-dialkyl derivatives with yields of 80–92%. Performance of the reaction with phase transfer catalysts allows the use of alkylsulfates and alkylsulfonates besides alkyl halides. The use of a branched alkylating agent (isopropyl iodide) increases, due to steric factors, the reaction time, and reduces the yield of the product of alkylation.

Spectrophotometric determination of trace amounts of quaternary ammonium salts in drugs by ion-pair extraction with bromophenol blue and quinine.

The sensitive and selective method reported here is based on the reaction of quinine cations with bromophenol blue (BPB) to form a 1:1 complex anion, which, with a quaternary ammonium salt at pH 6.7, is extractable into chloroform as an ion pair. Berberine and benzethonium were extracted in large amounts into chloroform with BPB only when quinine, in a pH 6.7 buffered aqueous solution, co-existed with them. In addition, when this showed a strong ion associate ability, then berberine and benzethonium could react in the organic phase with BPB to give a blue product. The absorbance of the ion associate in chloroform was measured at 610 nm. Calibration graphs were linear in the range 0.5 × 10–6–3.0 × 10–6M for berberine and benzethonium. Molar absorptivities were 3.75 × 104 l mol–1 cm–1 for the berberine associate and 3.14 × 104 l mol–1 cm–1 for the benzethonium associate. The blue associate can be used for selective and sensitive spectrophotometric determination of berberine and benzethonium in multi-component drugs.

Oxydation d'alcools par l'anhydride chromique dans les conditions du transfert de phase solide-liquide.

Resume Catalytic amounts of quaternary ammonium salts afforded efficient oxidation of alcohols by chromium trioxide at room temperature in organic solvents.