Haber process for the synthesis of ammonia

The Haber process for the synthesis of ammonia is one of the most significant industrial processes for the well-being of humanity. It is used extensively in the production of fertilizers as well as polymers and other products, (a) What volume of hydrogen at 15.00 atm and 350.°C must be supplied to produce 1.0 tonne (1 t = 10 kg) of NH3 (b) What volume of hydrogen is needed in part (a) if it is supplied at 376 atm and 250.°C ... 

The reactant is adsorbed on the catalyst s surface. As a reactant molecule attaches to the surface of the catalyst, its bonds are weakened and the reaction can proceed more quickly because the bonds are more easily broken (Fig. 13.36). One important step in the reaction mechanism of the Haber process for the synthesis of ammonia is the adsorption of N2 molecules on the iron catalyst and the weakening of the strong N=N triple bond. 

Like the Haber process for the synthesis of ammonia, this reaction represents a way of converting elemental nitrogen into a compound (nitrogen fixation). Moreover, calcium cyanamide reacts with steam at high temperature to yield ammonia,... 

With the technical development achieved in the last 30 years, pressure has become a common variable in several chemical and biochemical laboratories. In addition to temperature, concentration, pH, solvent, ionic strength, etc., it helps provide a better understanding of structures and reactions in chemical, biochemical, catalytic-mechanistic studies and industrial applications. Two of the first industrial examples of the effect of pressure on reactions are the Haber process for the synthesis of ammonia and the conversion of carbon to diamond. The production of NH3 and synthetic diamonds illustrate completely different fields of use of high pressures the first application concerns reactions involving pressurized gases and the second deals with the effect of very high hydrostatic pressure on chemical reactions. High pressure analytical techniques have been developed for the majority of the physicochemical methods (spectroscopies e. g. NMR, IR, UV-visible and electrochemistry, flow methods, etc.). 

The Haber process for the synthesis of ammonia is one of the most significant industrial processes. 

One of the principal goals of chemical synthesis is to maximize the conversion of reactants to products while minimizing the expenditure of energy. This objective is achieved easily if the reaction goes nearly to completion at mild temperature and pressure. If the reaction gives an equilibrium mixture that is rich in reactants and poor in products, however, then the experimental conditions must be adjusted. For example, in the Haber process for the synthesis of ammonia from N2 and H2 (Figure 13.7), the choice of experimental conditions is of real economic importance. Annual U.S. production of ammonia is about 13 million tons, primarily for use as fertilizer. 

The Haber process for the synthesis of ammonia from H2 and N2 has been practiced since the beginning of the 20th century always with a massive Fe catalyst.29... 

To illustrate these ideas, let s return to the Haber process for the synthesis of ammonia from nitrogen and hydrogen, which we discussed extensively in Chapter 15 ... 

An attractive feature of biological systems is the enzyme-mediated reactions that they carry out under very mild ambient conditions. The industrial Haber process for the synthesis of ammonia from elemental hydrogen and nitrogen. 

Several reactions of industrial interest occur at inconveniently slow rates in the absence of a catalyst, but can be accelerated considerably by the solid surface of a metal. These include the Haber process for the synthesis of ammonia, the cracking of petroleum, the Fischer-Tropsch synthesis and others. Originally, it was thought that the main effect of the solid catalyst was presenting the reactants at considerably higher local concentrations than in the gas phase. However, this is not generally true, since in some cases, different surfaces cause a substance to react in different ways. We will analyse some of these. 

---