ammonium salts
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2022 ◽  
Vol 116 (1) ◽  
pp. 42-47
Author(s):  
Eva Salanci ◽  
Fils Andriamainty ◽  
Dominika Adamove ◽  
Roman Mikláš

The critical micelle concentration (CMC) of the selected surfactant belonging to quaternary ammonium salts with chemical designation N,N-dimethyl-N-(3-((1R,5S)-1,8,8-trimethyl-2,4-dioxo-3-azabicyclo[3.2.1]octane-3yl)propyl)hexadecane-1-amine bromide was determined. Simultaneously, the effect of the addition of various concentrations of NaCl, KCl, NaBr, and KBr salts on the CMC value of the substance was observed and compared with those obtained in an aqueous solution at T = 296,15 K. Based on the results obtained, it was concluded that NaCl and KCl salts decreased the critical micelle concentration, while NaBr and KBr salts did not support micellization and CMC values therefore increased. In the case of solutions of a substance in the salt environment, when compared to the substance's solution in distilled water, a decrease in partial molar volume was observed. From the concentration density dependencies of the substance, an ionization degree of α was determined. Finally, the molar Gibbs energy ∆G° was also calculated and found negative for all salt solutions, while increase with their increasing concentration.


Author(s):  
Sandro Luiz Barbosa Santos ◽  
Adeline C. Pereira Rocha ◽  
David Lee Nelson ◽  
Milton Souza Freitas ◽  
Antônio A. P. Fulgêncio Mestre ◽  
...  

Triglycerides of waste cooking oil reacted with methanol in refluxing toluene to yield mixtures of diglycerides, monoglycerides and fatty acid methyl esters (FAMEs) in the presence of 20% (w/w) catalyst/oil using the hydrophilic sulfonated silica (SiO2-SO3H) catalyst alone or with the addition of 10% (w/w) co-catalyst/oil [(Bun4N)](BF4) or Aliquat 336]. The addition of the ammonium salts to the catalyst lead to a decrease in the amounts of diglycerides in the products, but the concentrations of monoglycerides increased. Mixtures of [(Bun4N)](BF4)/catalyst were superior to catalyst alone or Aliquat 336/catalyst for promoting the production of mixtures with high concentrations of FAMEs. The same experiments were repeated using DMSO as the solvent. The use of the more polar solvent resulted in excellent conversion of the triglycerides to FAME esters with all three-catalyst media. A simplified mechanism is presented to account for the experimental results.


2022 ◽  
Vol 2022 (1) ◽  
pp. pdb.prot100735 ◽  
Author(s):  
Michael R. Green ◽  
Joseph Sambrook

In this protocol, hybridization is first performed in conventional aqueous solvents at a temperature well below the melting temperature, and the hybrids are then washed at higher stringency in buffers containing quaternary alkylammonium salts. TMACl is used with probes that are 14–50 nt in length, whereas TEACl is used with oligonucleotides that are 50–200 nt in length.


2021 ◽  
Vol 19 (4(76)) ◽  
pp. 20-32
Author(s):  
Vasyl M. Britsun ◽  
Nataliya V. Simurova ◽  
Inna V. Popova ◽  
Oleksii V. Simurov

Aim. To generalize and systematize information on the properties of modern chemical disinfectants and antiseptic agents (DA and AA) – peroxide compounds, surfactants, salts of heavy metals and metals of variable valence in the highest oxidation state, alcohols, phenols and quaternary ammonium salts.Results and discussion. The classification of DA and AA by the chemical structure was performed. The spectrum of their activity, directions and forms of DA and AA were given. Toxicity and the impact on the environment were described.Conclusions. The results of the study conducted allow us to state that modern DA and AA of a wide spectrum of action are peracetic acid and, to a certain extent, hydrogen peroxide. However, they are unstable in dilute solutions. Other reagents are chemically stable, but they are characterized by a weak or average action against spores and viruses. The most effective DA and AA are mixtures (combinations) of compounds belonging to different classes. The examples of these combinations are “surfactants + biguanidine derivatives”; “quaternary ammonium salts + phenol derivatives”; “surfactants + aldehydes”; “quaternary ammonium salts + hydrogen peroxide”. These mixtures combine the advantages and compensate for the disadvantages of individual DA and AA.


Author(s):  
Guanmeng Li ◽  
Weifeng Zhang ◽  
Yan Zhang ◽  
Yangjin Lee ◽  
Zihan Zhao ◽  
...  

ChemCatChem ◽  
2021 ◽  
Author(s):  
Haibo Zhu ◽  
Yingying Zhang ◽  
Qiangwen Fan ◽  
Liu Yang ◽  
Zongbo Xie ◽  
...  
Keyword(s):  

Author(s):  
Kiki Varikou ◽  
Antonis Nikolakakis ◽  
Dimitris Bitsakis ◽  
Zacharias Skarakis ◽  
Nikos Garantonakis ◽  
...  

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