Anhydrides acidity/basicity

Particularly, some newly developed drags, which incorporate the N-acyl sulfonamide moiety [8-10], are synthesized from the parent sulfonamides, by their coupling with acid chlorides or carboxylic anhydrides in basic conditions [11-15]. Unfortunately all these methods lead to substantial waste products. Less common reports mentioning this transformation under acidic conditions (Bronsted or Lewis acids) do not systematically examine the purpose and limitations of the reaction [16]. 

XVIII. Basic Anhydride + Acid —> Salt + Water... 

The name of this structural class ( quinoline ) in the Colour Index is not ideal because quinoline derivatives feature in other related classes, such as the methine basic dyes with a quinolinium cationic group. The class is more precisely associated with quinophthalone (1.15), the characteristic chromogen derived by condensation of quinoline derivatives with phthalic anhydride. This small class of yellow compounds contributes to the disperse, acid, basic and solvent ranges of dyes. 

Anhydrides — Acids and Salts — Basic and Acid Chlorides—The Borates—The Carbonates and Thiocarbonates—Other Acids containing Carbon their Saits with Alcohol Radicals—The Silicic Acids and the Silicates. 

Classify each of the following as an acidic anhydride, a basic anhydride, or neither ... 

Acids. Acidic oxides, acid anhydrides. Bases, basic oxides. Neutralization—hydrogen ion plus hydroxide ion. Hydronium ion. Equivalent weights of acids and bases. Normality. Monoprotic, diprotic, and triprotic acids. Monohy-droxic, dihydroxic, and trihydroxic bases. 

Ammonia and amines react with partially or fully activated carboxylic acid derivatives (acylating reagents) like acid anhydrides, acid halides, ammonium salts of monoesters, monoamides with heating, diesters under basic conditions and dinitriles after partial hydrolysis. ... 

Acidic anhydrides are nonmetallic oxides that react with water to form acids. Basic anhydrides are metallic oxides that react with water to form bases. 

Poly(ortho ester)s were the first polymers used to prepare surface eroding devices, but additional excipients such as acid anhydrides or basic excipients in the interior of the matrix, had to be used to prevent bulk erosion [79, 81]. 

Nitro-l-propanol should be stored in cylinders and stored in well-ventilated and dry environment at 2-8 °C. It cannot be stored together with acidic/basic materials, and must be far away from the fire, acidic chloride and acid anhydride. 

Acidic substances e.g. maleic anhydride, trifluoroecetic acid Basic substances e.g. benzylamine, ethanolamine... 

In general, acylation reactions for chromatography are carried out with three main types of acylating reagent acid anhydrides, acid halides and reactive acyl derivatives such as acylated imidazoles, acylated amides or acylated phenols, and the different types are chosen for different reasons. Acyl halides are highly reactive, which may be important with compounds that are difficult to acylate, because of steric factors for instance. A drawback to acyl halides is that a basic acceptor for the halogen acid produced in the reaction is usually required (equation (8)),... 

Esters react with water under either acid or base conditions to give the acid, but the leaving group is now RO rather than Cl or O2CR, as in the previous reactions with acid chlorides or acid anhydrides. For basic hydrolysis conditions, the experiment requires two steps to convert the ester to the acid. Isopropyl acetate (19), for example, is heated to reflux in aqueous NaOH... 

Virtually all treatments in commercial use are chosen to chemically bond an organic species to the filler surface, thus improving compatibility with organic polymers. The most common functionalities used for this are acids or acid precursors, such as anhydrides (for basic or amphoteric fillers) and alkoxy-silanes (for fillers with metal hydroxyls present, especially siliceous fillers). Organo-titanates and related compounds are also proposed for nse with a wide variety of fillers. 

Yonemitsu et al. [46] modified the Yamaguchi conditions in which the mixed anhydride is not isolated and DMAP is directly introduced at room temperature from the beginning. Shiina et al. [47] described the use of 2-methyl-6-nitrobenzoic anhydride (MNBA) as an alternative to 2,4,6-trichlorobenzoyl chloride. Pivaloyl chloride [48], trifluoroacetic anhydride [49], AC2O [50], and B0C2O [51] are also employed for the lactonization via mixed anhydride under basic conditions. Furthermore, Yamamoto et al. [52] described the use of Sc(OTf)3 as a Lewis acid. 

For chemical processes, some examples are the elimination of aromatics by sulfonation, the elimination of olefins by bromine addition on the double bond (bromine number), the elimination of conjugated diolefins as in the case of the maleic anhydride value (MAV), and the extraction of bases or acids by contact with aqueous acidic or basic solutions. 

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