Cation characteristics

Hence, acids can be defined as substances producing cations characteristic of the solvent (solvo-cations, for example NH4, NO ), and bases as substances producing anions characteristic of the solvent (solvo-anions, for example OH , NH, NO3). This concept has been applied to solvents such as liquid sulphur dioxide, liquid hydrogen chloride and pure sulphuric acid. 

Electrodialysis units recover plating chemicals differently from the recovery units discussed thus far. In electrodialysis, electromotive forces selectively drive metal ions through an ion-selective membrane (in RO, pressure is the driving force in ion exchange, the driving force is chemical attraction). The membranes are thin sheets of plastic material with either anionic or cationic characteristics.33... 

According to the Arrhenius theory of acids and bases, the acidic species in water is the solvated proton (which we write as H30+). This shows that the acidic species is the cation characteristic of the solvent. In water, the basic species is the anion characteristic of the solvent, OH-. By extending the Arrhenius definitions of acid and base to liquid ammonia, it becomes apparent from Eq. (10.3) that the acidic species is NH4+ and the basic species is Nl I,. It is apparent that any substance that leads to an increase in the concentration of NH4+ is an acid in liquid ammonia. A substance that leads to an increase in concentration of NH2- is a base in liquid ammonia. For other solvents, autoionization (if it occurs) leads to different ions, but in each case presumed ionization leads to a cation and an anion. Generalization of the nature of the acidic and basic species leads to the idea that in a solvent, the cation characteristic of the solvent is the acidic species and the anion characteristic of the solvent is the basic species. This is known as the solvent concept. Neutralization can be considered as the reaction of the cation and anion from the solvent. For example, the cation and anion react to produce unionized solvent ... 

Although it is not necessary for autoionization to occur, the solvent concept shows that the cation characteristic of the solvent is the acidic species and the anion is the basic species. Therefore, when... 

The acidity of liquid HF is high enough that it can function as an acid catalyst in many instances. The cation characteristic of the solvent, H2F+, is generated when HF reacts with a strong Lewis acid that is capable of forming stable fluoride complexes. The reactions with BF3 and AsF5 are typical ... 

Because the cation characteristic of the solvent is IF4+, it is reasonable to assume that the ion may have some existence in other situations. As with the other polyatomic ions shown so far, the reaction selected involves a strong Lewis acid such as SbF5 to remove l , and the same approach is taken for producing C1F4+ and BrF4+ in the interhalogen solvents. 

Just as the cation produced by dissociation of water (H30+) is the acidic species in aqueous solutions, the NH4+ ion is the acidic species in liquid ammonia. Similarly, the amide ion, NH2, is the base in liquid ammonia just as OH- is the basic species in water. Generalization to other nonaqueous solvents leads to the solvent concept of acid-base behavior. It can be stated simply as follows A substance that increases the concentration of the cation characteristic of the solvent is an acid, and a substance that increases the concentration of the anion characteristic of the solvent is a base. Consequently, NH4C1 is an acid in liquid ammonia, and NaNH2 is a base in that solvent. Neutralization becomes the reaction of the cation and anion characteristic of the particular solvent to produce unionized solvent. For example, in liquid ammonia the following is a neutralization ... 

STEPANQUAT F is an excellent dispersing agent. Small quantities of it are sufficient for fluidizing and stabilizing concentrated dispersions with 15 to 30% STEPANTEX in water (STEPANTEX 6530B). The performance of such formulations will be improved due to its cationic characteristics. 

This class of nonionic surfactants has not been used largely in cleaning detergents. However, it is noteworthy that these materials in acidic solution can exhibit cationic characteristics, whereas, in neutral or alkaline solution, they are nonionic [3, 4]. 

The correlation between the three kinds of data is shown in Figure 18 which shows that the cation characteristic Nj binding energy (component 2) is linearly correlated to the corresponding NH stretching vibration and heat of adsorption of pyrrole. 

Comments cationic emulsifying wax is claimed to be of particular value in cosmetic and pharmaceutical formulations when cationic characteristics are important. Thus it can be used in medicated creams, germicidal creams, ointments and lotions, hair conditioners, baby creams, and skin care products in which cationic compounds are included. Cationic emulsifying wax is compatible with cationic and nonionic materials, but is incompatible with anionic surfactants and drugs. Additional antimicrobial preservatives should be included in creams. Cetrimide may cause irritation to the eye see Cetrimide. 

A possibly serious defect in the design of compounds such as the piperidinium (222), the morpholinium (223), the tropines (226) and (227), and the decahydroquinoliniums (228) is that these molecules do not bear the trimethylammonium cation characteristic of acetylcholine, but rather the quaternary head is a part of a ring system. It was indicated previously that incorporation of the nitrogen atom of acetylcholine itself into a ring is detrimental to cholinergic activity and potency. 

Arrhenius and Bronsted-Lowry acid-base neutralization reactions all have one thing in common. They involve the reaction of an acid with a base to form a salt that contains the cation characteristic of the base and the anion characteristic of the acid. Water is also usually formed. This is indicated in the formula unit equation. The general form of the net ionic equation, however, is different for different acid-base reactions. The net ionic equations depend on the solubility and extent of ionization or dissociation of each reactant and product. 

In a self-ionizing solvent, an acid is a substance that produces the cation characteristic of the solvent, and a base is a substance that produces the anion characteristic of the solvent. 

The more general working definition of acids and bases we have been using is due to Franklin, who in 1905 developed a theory in which the solvent plays a central role. According to this view, an acid is a solute that gives rise to a cation characteristic of the solvent, and a base is a solute that jdelds a dissolved ion which is also characteristic of the solvent. 

Effect of Divalent Cation Characteristics on Gelation Process.280... 

Cerilpyridiniutii chloride is the 1-hexadecylpyridinium chloride (USP/NF-. Eur.Ph.-, BP-, and Martindate-compliant). Lin et al. (33) compared the primaiy ocular and dermal irritations of several quaternary ammonium compounds. They concluded that the irritancy of these compounds is likely to be related to their solubility in addition to their cationic characteristics. Only celylpyridinium chloride is very soluble in both lipids and w er. It appears that not all of the quaternary ammonium compounds studied are irritant, but celylpyridinium chloride was severely irritating to the skin of the test animal. In a recent work. Green et al. (34) confirmed that ophthalmic medications containing celylpyridinium chloride are potentially hazardous to the comeal endothelium. 

Amphoteric surfactants comprise a broad range of compounds, which display nonionic, cationic, or even anionic tendencies depending on pH or in-use conditions. Betaines, imadazoline-derived amphoacetates, alkylamino propionates, and glycinates are generally included in this category. Amine oxides, which may exhibit nonionic or cationic characteristics depending on pH conditions, are also included in this category. 

Cady and Elsey gave the so-called solvent-system definitions, which depend on the mode of self-ionization of the particular solvent. Each solvent is considered as a parent of acids and bases. A solvo-acid is defined as a solute which increases the concentration of cations characteristic of the pure solvent and a solvo-base as a solute which increases that of the anions characteristic of the pure solvent ... 

Neutralization reactions involve the reaction of an acid with a base to form a salt that contains the cation characteristic of the base and the anion characteristie of the aeid. Water is also usually formed. 

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