Ammonium salts, quarternary

Unloaded silica does not recover HPA from aqueous solution. The surface of silica gel modified with quarternary ammonium salts (QAS) gets anion-exchange properties. The aim of the work is the elaboration of solid-phase reagents on the base of ion associate of HPA with QAS immobilized onto silica surface for the determination of phosphoms and organic reductants. Heterocyclic (safranine and lucigenine) and aliphatic (trinonyloctadecyl ammonium iodide and tetradecyl ammonium nitrate) compounds have been examined as QAS. 

A method for the depolymerisation of PETP fibres using quarternary ammonium salt phase transfer catalysts in saponification processes at atmospheric pressure and temperatures as low as room temperature is reported. Terephthalic acid was produced in yields as high as 93%. Also reported are similar processes for the depolymerisation of nylon 66 and nylon 46 fibres. Nylon 46 oligomers produced were repolymerised using solid-state polymerisation to produce high molecular weight nylon 46. Nylon 66 was depolymerised to produce oligomers and adipic acid in reasonable yields. 11 refs. USA... 

In the following example, although the synthesis of the azoniaspirocycle does not involve an acyclic compound, the reaction itself is very similar to those described in this section, hence its inclusion here (Equation 34). Maruoka and co-workers have designed a C2-symmetric chiral quarternary ammonium salt, which is then employed as a phase-transfer catalyst in an enantioselective alkylation <1999JA6519, 2001JFC(112)95, 2004TA1243>. 

Heating 101 with aqueous sodium hydroxide in diethyleneglycol monomethyl-ether or with alkali acetate, a reaction which may also be performed in other polar organic solvents, such as dimethylformamide, N-methylpyrrolidone, or di-methylacetamide at 150°C to 210°C, also provides pyranthrone. As an alternative, 101 may be cyclized to form pyranthrone in a two-phase reaction, carried out in the presence of quarternary ammonium salts in a phase-transfer system comprising an aqueous and an organic phase [20]. 

Substitution up to 20% is possible at 80°C even in water, in which PVC is quite insoluble, by use of thiophenoxide together with a surfactant such as quarternary ammonium salt. 

Cationic Detergents Cationic detergents are quarternary ammonium salts of amines with acetates, chlorides or bromides as anions. Cationic part... 

Synthesis and Characterization of Lignin-like Model Epoxide. A series of epoxidation reactions were performed with hydroxypropyl guaiacol (HPG) as model compound and ECH. Molar ratios of ECH HPG varied from 1 to 10. Pelletized KOH and a quarternary ammonium salt (QAS) served as catalyst and reagent. Toluene was the solvent. Catalyst concentration and method of addition were varied. Experimental details are given elsewhere (11). 

J. Haberman T.C. Castorina, The Surface Chemistry of HMX , PATR 3089 (1963) [A study was made of the solution-adsorption properties of HMX using a 14C labeled quarternary ammonium salt, stearyl tri-methyl ammonium bromide (STAB). The solvent system used consisted of 10% ethanol and 90% w. The solution-adsorption system isotherms for 10-micron HMX were measured. The authors conclude that an H-type Langmuir adsorption isotherm is obtd, the adsorption of STAB on HMX is reversible and therefore physi-... 

Alkynes.10 Alkynes can be prepared by double dehydrobromination of pic-dibromides in petroleum ether by use of powdered KOH and catalytic amounts of a phase-transfer catalyst. Tetraoctylammonium bromide, 18-crown-6, or even Aliquat 336 are much more effective than more hydrophilic quarternary ammonium salts, such as tetrabutylammonium hydrogen sulfate, previously used (7, 354-355)." Isolated yields are 80-98%. Yields are generally lower when mc-dichlorides are used as the starting material. 

The first two processes are called thermal, because they can also be induced by classical Joule- or non-laser radiative heating, usually in conjunction with heat conduction to the sample surface. Thermal evaporation of cations of quarternary ammonium salts and anions of sodium tetraphenylborate has been demonstrated by several groups (13. 1, 15). Such a thermal evaporation of ions, common for metals and inorganic salts such as alkalihalides, had not originally been expected to occur for organics as well. It should be most pro-... 

Fig. 10 Example of a contact-killing and microbe-releasing surface. The scheme shows the design of a two-level dual-functional antibacterial coating containing both quarternary ammonium salts and silver. The coating process begins with LbL deposition of a reservoir made of bilayers of PAH and PAA. (A) Cap region made of bilayers of PAH and SiC>2 nanoparticles (NP) is added to the top. (B) The SiC>2 nanoparticle cap is modified with a quarternary ammonium silane (QAS) PEM polyelectrolyte multilayer. (C) Ag+ is loaded into the coating using the available unreacted carboxylic acid groups in the LbL multilayers. Scheme was reproduced from [138]...

Most amines react with CaSi2 in form of their hydrogen halides but the quarternary ammonium salts do not react257. The reaction becomes weaker with a larger organic group. The primary amines react better than the secondary and tertiary amines. 

Strong Quarternary ammonium salt Free anions from acid or base salts 1-10... 

Starting with enantioselectivities of below 10% ee at the beginning, a subsequent increase of the asymmetric induction was achieved when using individually made chinchona-derived quarternary ammonium salts. While /V-bcnzylchinchonium reached approximately 30% ee, the use of analogue p-substituted derivatives led to enantioselecivities of up to 60% ee. Subsequent process development led to an efficient enan-tioselective alkylation process with enantioselectivities of up to 94% ee... 

We shall study the following problem A quarternary ammonium salt containing an electron withdrawing substituent W on one of the carbons attached to the nitrogen atom yields a rearranged tertiary amine on being treates with a base (Stevens rearrangement) (Eq. 56). 

Similarly, alkylation of 6-methyl-2-methylene-l,3,6-dioxazocane with methyl iodide cleanly affords the corresponding quarternary ammonium salt <2004AGE1117>. 

The catalytic activity of quarternary ammonium salt usually depends on the corresponding catalyst cation and counter anion[2]. For a series of tetraalkylammonium chlorides, the activity increased in the order of TP AC < TBAC < TOAC. Bulky quaternary salts, having longer distance between cation and anion, are generally known to exhibit higher activity in activating anions[3]. This explains why they are more effective in nucleophilic attack of the anion to oxirane ring of GVE. Table 1 also shows that the rate constant with different halide anions of the quaternary ammonium salts decreases in the order of Cf > Bf > T. This is consistent with the nucleophilicity of the halide anions. 

The bis-quarternary ammonium salt has not yet been synthesized, even with a polar solvent (CH3CN). 5a is obtained as colorless crystals. Elemental analysis and NMR spectroscopy confirm the considered structure. 

Gordon, J.E. Characterization of quarternary ammonium salts, phase equilibria for salt-salt and salt-nonelectrolyte systems. J. Am. Chem. Soc., 1965, 87, p. 4347-58. 

It is emphasized that amine groups can react with -CH2CI groups to produce quarternary ammonium salts when the concentration of the functionality is high (3). 

Carboxylic acid anhydrides from quarternary ammonium salts... 

Another group of complexing agents, especially useful for charged polysaccharides, are such quarternary ammonium salts as cetyltrimethyl-ammonium bromide or cetylpyridinium bromide. Scott has summarized the work in this field. Acidic polysaccharides form insoluble complexes... 

When methyl iodide and ammonia are heated together, the reaction does not stop with the formation of the salt of the secondary amine. The amine is liberated, and by the addition of another molecule of the iodide is converted into the salt of tri-methylamine, (CH3)3NHI. Still another step in the reaction takes place. The tertiary amine is set free and a quarternary ammonium salt is formed as the result of the addition of methyl iodide —... 

For the synthetic fibre poly(ethylene terephthalate) it is very important to impart antistatic properties to it [175]. Studies on the effect of the structure of cationic surfactants on the half-life time of static charge decay and surface resistivity (Rs) of PET fibres show best results with a methylated quarternary ammonium salt of a stearyl amine-ethylene oxide adduct or hydrochloride of a lauryl amine-EO adduct with 10 EO. 

The cyclopolymerization of dipropargyl monomers carrying an ionic nature is a facile synthesis method for self-doped conjugated ionic polymers. Various dipropargyl quarternary ammonium salts were polymerized to yield the unusual conjugated polymers. The potential counterions are ionically bound to the... 

Catalyst benzyl dimethylamine. Catalyst Arquad quarternary ammonium salt. ... 

The desilylation of 3,5-diaryl-l,2,4-thiadiazole quarternary ammonium salts 7 with CsF results in ring expansion to afford substituted 277-1,3,5-thiadiazines 10 in moderate yield (Equation 56) <1999J(P1)1709>. Ab initio studies have been carried out for this transformation and the details are presented in Section 9.09.2. 

Thomson, T., and T. S. Stevens Degradation of Quarternary Ammonium Salts, Part V. Molecular Rearrangement in Related Sulphur Compounds. J. Chem. Soc. (London) 1932 69. 

Table 4. Typical Selectivity Coefficients, Log y for the Uquid-Membrane Electrodes Based on Porphyrins and Quarternary Ammonium Salts (QAS)...

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