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Published in Karen D. Sam, Thomas P. Wampler, Analytical Pyrolysis Handbook, 2021
Cationic surfactants generally contain a central heteroatom with four side groups extending from the central atom. A class of surfactants known as quaternary ammonium salts contain typically three small aliphatic or aromatic groups bonded to a central nitrogen atom. The cleansing properties arise from the presence of the fourth group, which is a long aliphatic chain. The length of this chain varies from C12 to C20. The aliphatic chain, which is derived from the reaction of the amine with a fatty acid, is crucial to the formation of the micelle. Micelle formation is the mechanism by which surfactants get their cleansing properties. Commercially available cleaning products contain a mixture of quaternary ammonium salts. To understand how pyrolysis can be used to analyze these materials, the pyrolysis products of the pure components may be examined. A generic quaternary ammonium salt with the chemical structure:
Surface-altered poly(methyl methacrylate) resin for antifungal dentures
Published in Badal Jageshwar Prasad Dewangan, Maheshkumar Narsingrao Yenkie, Novel Applications in Polymers and Waste Management, 2018
Abhay Narayane, Akshay Mohan, Siddharth Meshram
This is important as the denture is usually infected with C. albicans which will cause reinfection if it is not removed. The common antiseptic solution includes alkaline peroxides or hypochlorites which may overtime corrode the metal components of dental appliances. Quaternary ammonium salts (QASs) have been widely used in paint, water treatment, textiles, and food industry because of low toxicity and broad antifungal spectrum. They can also be chemically bound to the polymer carriers via active groups, thus integrating QAS monomers with composite matrix. As compared with the conventional antifungal agents of low molecular weight, the advantages of these polymerizable antibacterial agents include nonvolatility, chemical stability, and low permeation through skin. Hence, the application of QAS monomers to dentistry may provide more choices for development of dental antifungal materials.
Synthesis and properties of double epoxy groups double quaternary ammonium salts
Published in Journal of Dispersion Science and Technology, 2023
Guixin Li, Feng Ma, Junying Li, Guangxu Chen, Pengfei Yang, Ning Yu, Jianhui Chen, Yongle Wang, Xinyu Zhang
Quaternary ammonium salt (QAS, general formula R4N+X−) is a cationic compound that four hydrogen atoms in ammonium are all replaced by organic groups. It is a kind of surfactant with good bactericidal property due to the cationic quaternary ammonium group. QAS commonly used as bactericidal agent and disinfectant, it has a broad-spectrum antibacterial activities,[1] mainly in the inhibition of bacteria and fungi, of course, it also has a certain effect on viruses.[2,3] There are many types of cationic surfactants based on quaternary ammonium salts. Generally, QAS are produced by the nucleophilic substitution reaction of tertiary amines (alkyl amine or heterocyclic amine) with an alkyl halide or similar material.[4,5]
Synthesis of novel quaternary ammonium salts from 1, 2-benzothiazine derivatives
Published in Journal of Sulfur Chemistry, 2021
Salman Gul, Maria Saleem, Munawar Ali Munawar, Hafiz Adnan Ahmad, Ejaz Ahmed, Robina Begum, Zahoor H. Farooqi
Quaternary ammonium salts are ionic compounds that may be represented as NR4+Y−, where R may be the same or different groups and Y− is a replaceable counter anion. NR4+Y− system is a result of replacement of all four of the hydrogen atoms directly bonded to the nitrogen from NH4+Y− by aryl, alkyl or some other groups. The synthesis and characterization of quaternary ammonium compounds have gained much attention in the field of organic chemistry due to their potential use as versatile, nontoxic and cheap phase transfer catalyst in different organic reactions [1]. These compounds are used as a catalyst to initiate and to speed up various organic reactions like Williamson synthesis [2] and Michael addition [3]. It has also been found that quaternary ammonium salts are superior over other phase transfer catalytic systems like polyethylene glycol and crown ethers. They have phase transfer activity comparable to that of cryptands. Moreover, applications of cryptands, polyethylene glycol and crown ethers are limited, and their high concentration is needed to achieve their phase transfer activity. They are also known for their excellent antimicrobial abilities [4]. The synthesis of various quaternary ammonium compounds with different functionalities from various starting materials has been recently reviewed by various groups [5,6]. To the best of our knowledge, the synthesis and characterization of thiazine-based quaternary ammonium compounds have been rarely reported in the literature, and it needs to be explored for their versatile applications.
Equilibrium adsorption modelling of selected crude oil components following a spill on Niger Delta soil
Published in Chemistry and Ecology, 2021
Nnamdi David Menkiti, Chukwuemeka Isanbor, Olusegun Ayejuyo
Lee and Kim [25] partitioned naphthalene onto the surface of kaolinite and halloysite by the surfactant HDTMA. They obtained a linear adsorption process that could be described by a dependent on the arrangement of the surfactant cations distribution process. Bastani et al. [26] calcined diatomite to the improved surface area with increased sorption capacity. Functionalised modification using surfactants changes the character of mineral materials such as organoclays [27], activated carbon and bentonite [28] and Zeolites [29,30] surfaces from hydrophilic to hydrophobic, which usually increases the affinity of the sorbent for organic pollutants. This modification is expensive and presents toxicity-related problems because of the quaternary ammonium salts [31]. The goal was to understand the mechanism of interaction of contaminants or crude oil components with natural soil in the Niger Delta region. For instance, the organic carbon content in soil determines the degree of sorption of non-polar organic compounds in soil [32,33], while non-ionisable nitrogen, sulphur and oxygen compounds (NSOs) such as benzothiophene, non-specific interaction (namely van der Waals forces) appear to be dominant in the sorption to clay till [34]. Also, compounds such as pyridine, pyrrole carbazole, indole, benzene and thiophene show a certain polarity which indicates an additional interaction may be playing an important role. Since crude oil is a mixture of complex compounds, this study aims at determining the mechanism of the sorption of crude oil onto the soil in the Niger Delta region through the use of environmentally important constituent of crude oil (phenol, pyridine and phenanthrene) to elucidate the sorption mechanism.