Solid-acid-based Nitration

When we mix two solutions the result is often simply a new solution that contains both solutes. However, in some cases the solutes can react with each other. For instance, when we mix a colorless aqueous solution of silver nitrate with a clear yellow aqueous solution of potassium chromate, a red solid forms, indicating that a chemical reaction has occurred (Fig. 1.1). This section and the next two introduce three of the main types of chemical reactions precipitation reactions, acid-base reactions, and redox reactions, all of which are discussed in more depth in later chapters. (The fourth type of reaction discussed in this text, Lewis acid-base reactions, is introduced in Section 10.2.) Because many chemical reactions take place in solution, particularly in water, in this section we begin by considering the nature of aqueous solutions. 

Elemental composition P 37.78%, H 3.69%, 0 58.54%. The acid in solid form may be identified by its physical properties. Aqueous solution may be heated and phosphorus acid is converted to phosphoric acid which is measured for orthophosphate ion by ion chromatography or colorimetry (see Phosphoric Acid). A cold aqueous solution may be analyzed for phosphite ion by ion chromatography, following appropriate dilution. Strength of the acid in an aqueous solution may be measured by acid-base titration using a standard solution of alkali. Also, titration against a standard solution of silver nitrate using potassium chromate as indicator may serve as an additional confirmatory test. 

Ammonium halides have been used as versatile reagents in low-temperature solid-state redox and acid-base reactions. For example, direct reaction with the appropriate metal at 270-300° yields the ammonium salts of ZnClq , LaCls ", YCl6 , YBre, CuCb , etc., whereas Y2O3 yields either (NH4)3YBr6 or YOBr depending on the stoichiometric ratio of the reagents. Solid-state reactions of ammonium sulfate, nitrate, phosphates and carbonate have also been studied. 

The advantage of using vapor phase conditions is the continuous thermal removal of water and the simple implementation of a continuous nitration process based on a fixed-bed of the solid acid. Elevated reaction temperatures, however, lead to problems of safety, catalyst stability, and by-product formation, and optimization... 

AMINONAPHTHALENE (134-32-7) C10H5N C10H7NH2 Combustible solid (flash point 315°F/157°C autoignition temp 860 to 905°F/460 to 485°C Fire Rating 1). Oxidizes in air turns red. A weak base. Violent reaction with strong oxidizers nitric acid cellulose nitrate (of high surface area) ... 

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