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Chemical Methods
Published in Jerome Greyson, Carbon, Nitrogen, and Sulfur Pollutants and Their Determination in Air and Water, 2020
But what are acids and bases? Although there are alternative definitions for them, the one most useful for chemical analysis defines an acid as a substance that tends to donate protons to other substances and a base as a substance that tends to accept them. By definition, for every acid, there is also a conjugate base. That is, after an acid donates it proton to another base, the residual deprotonated moiety is called the acid’s conjugate base. Thus, in the reaction HA=H++A−
Acids and Bases
Published in Michael B. Smith, A Q&A Approach to Organic Chemistry, 2020
A conjugate base is one of the two products of the reaction between a base and an acid. Specifically, when a Brønsted–Lowry base donates electrons to the hydrogen atom of an acid, the acid loses that hydrogen to the base, leaving behind the conjugate base of the initial acid. In the reaction, the oxygen atom of hydroxide donates two electrons to the acidic hydrogen of HCl to “pull” the proton away from HCl, with concomitant cleavage of the H—Cl bond to give the chloride ion. In other words, loss of the hydrogen atom from HCl leaves behind the electrons in the HCl bond, forming the chloride ion. In this reaction, the chloride ion is the conjugate base of HCl and the sodium counterion is transferred from NaOH to NaCl.
Synthesis, spectral characterisations of 3t-pentyl-2r,6c-diarylpiperidin-4-one oxime picrates: DFT studies and potent anti-microbial agents
Published in Molecular Physics, 2022
S. Savithiri, G. Rajarajan, S. Bharanidharan, M. Arockia doss
By virtue of its Lewis acid behaviour, picric acid forms crystalline picrate salts with a variety of organic molecules and functions as a better acidic ligand in the creation of salts through particular electrostatic or hydrogen bonding interactions [6,7]. The nature of the partners participating in the bond-formation process determines the strength and kind of the electron donor–acceptor type bonding in the picric acid complexes. The linkage includes both the creation of chemical complexes and electrostatic interactions [8]. Due to the presence of phenolic OH, which encourages the formation of salts with diverse organic bases, picric acid derivatives are intriguing non-linear optical (NLO) possibilities. The picrate moiety, the conjugate base of picric acid, experiences a rise in molecular hyperpolarisability due to the proton transfer [9].
Fuel properties of B100 and blends of Terminalia belerica (Roxb.) oil biodiesel synthesised using SrO as a basic heterogeneous catalyst
Published in Biofuels, 2020
R. Sreekanth, S.S. Joshi, Rana Pratap Reddy
The ability of a catalyst surface to convert an adsorbed electrically natural acid indicator to its conjugate base is known as the catalyst's basic strength. The surface of the catalyst donates an electron pair to an indicator, and hence a colour change is observed and the basic strength of a solid catalyst is thus estimated qualitatively. Using acid indicators with wide range of pKa = pKBH values, one can estimate the basic strength of a given solid catalyst [22,23]. The basic strength H_ of a basic catalyst is given by Equation (2):where BH = the concentration of the indicator in its acidic form, B− = the concentration of the indicator in its basic form, and H_ = the basic strength of the Hammet indicator.
Thermotropic liquid-crystalline properties of extended viologen bis(triflimide) salts
Published in Liquid Crystals, 2018
Pradip K. Bhowmik, Shane T. Killarney, Jessa Rose A. Li, Jung Jae Koh, Haesook Han, Lewis Sharpnack, Deña M. Agra-Kooijman, Michael R. Fisch, Satyendra Kumar
The stabilities for all viologens were studied by TGA analyses and are defined as the temperature (°C) at which a 5% weight loss for each of the salts occurred at a heating rate of 10°C/min in nitrogen. Despite the presence of flexible alkyl chains, TGA thermograms of these salts as shown in Figure 9 show relatively high thermal stabilities that are in the temperature range of 338–365°C. These temperatures gradually decrease slightly with the increase in carbon number in the alkyl chain. Triflimide is one of best counterion that imparts the high thermal stability of ionic liquids and ionic polymers reported in the literature [45–47], because it has non-nucleophilic character being the conjugate base of a super acid. Therefore, it decomposes the cationic moieties nuclophilically at relatively high temperatures.