Industrial manufacture Ostwald Process

Nitric acid is an important industrial chemical (see Box 15.8) and is manufactured on a large scale in the Ostwald process, which is closely tied to NH3 production in the Haber-Bosch... 

Ammonia production in the world is presently as large as 110 million tonnes per year. The product is stored as a liquid at a pressure of 100 atm (10.1 MPa) and a temperature of -35.5°C. Ammonia is the base material for the manufacture of nitrogen oxides and various industrial products. Nitrogen oxides have a number of appHca-tions. NjO is used in medicine, as it has anesthetic properties (laughing gas). is used as an oxidizer in rocket fuel. From ammonia, nitric add is manufactured by oxidation with air at about 800°C. Different types of catalysts, e.g. platinum, may be used. NO, formed in the oxidation, is reacted with water to HNOj and NO. The technique is called the Ostwald process. 

Nitric acid is an important industrial chemical (Box 15.8) and is manufactured on a large scale in the Ostwald process, which is closely tied to NH3 production in the Haber-Bosch process. The first step is the oxidation of NH3 to NO (eq. 15.23). After cooling, NO is mixed with air and absorbed in a countercurrent of water. The reactions involved are summarized in scheme 15.116. This produces HNO3 in a concentration of 60% by weight and it can be concentrated to 68% by distillation. 

Nitric acid is produced industrially by the Ostwald process. The majority of HNO3 is used in the manufacture of fertilizers. 

The importance of catalysts in chemical reactions cannot be overestimated. In the destruction of ozone previously mentioned, chlorine serves as a catalyst. Because of its detrimental effect to the environment, CFCs and other chlorine compounds have been banned internationally. Nearly every industrial chemical process is associated with numerous catalysts. These catalysts make the reactions commercially feasible, and chemists are continually searching for new catalysts. Some examples of important catalysts include iron, potassium oxide, and aluminum oxide in the Haber process to manufacture ammonia platinum and rhodium in the Ostwald synthesis of nitric... 

Catalysis refers to the phenomenon by which the rate of a chemical reaction is accelerated by a snbstance (the catalyst) not appreciably consnmed in the process. The term catalysis was coined by Berzelins in 1835 and scientifically defined by Ostwald in 1895, but applications based on catalysis can be traced back to thousands of years ago with the discovery of fermentation to produce wine and beer. Nowadays, catalysts are used in 80% of all chemical industrial processes, and create annual global sales of about 1500 billion dollars and contribute directly or indirectly to approximately 35% of the world s GDP. Catalysis is central to a myriad of applications, including the manufacture of commodity, fine, specialty, petro-, and agro- chemicals as well as the production of pharmaceuticals, cosmetics, foods, and polymers. Catalysis is also an important component in new processes for the generation of clean energy, and in the protection of the enviromnent both by abating environmental pollutants and by providing alternative cleaner chemical synthetic procedures. 

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