Nitric acid synthesis from ammonia

If similar processes could be developed at energy conversion efficiency levels that are comparable to the present day SMR-based NH3 synthesis plants, then it would be possible to realize a major reduction in the production costs of ammonia-borane complex. We note that a concept similar to that discussed above has already been developed for nitric acid synthesis process based on boron nitride analogous to the Haber-Bosch route for nitric acid production from NH3. Finally, recent results have shown that unusual parallel behavior exists between hydrocarbons and their corresponding B-N analogues. Thus, hydrogenation of benzene to cyclohexane may also provide a model for the reformation of borazine to other amine-boranes. 

The alchemists referred to nitric acid as aqua fortis ( strong water ) out of respect for its capacity to dissolve silver from alloys of gold. Its industrial synthesis from ammonia has been described earlier however, small amounts... 

Industrial fertilizer synthesis starts from ammonia synthesis, and ammonia is then easily oxidized in a separate reactor to nitric oxide over PtRh wire gauze catalyst. Formation of nitric acid requires further oxidation of nitric oxide to nitrogen dioxide (NO2) and absorption of the nitrogen dioxide in water. Overall, three different chemical process plants are used for the synthesis of nitric acid. The ammonia synthesis reaction takes place in a high-tem-perature, high-pressure reactor that requires recycling of products due to the thermodynamic limitations of chanical conversion. The ammonia oxidation reaction is very fast and takes place over a very small reactor length. Finally, nitric acid synthesis takes place in absorption columns. 

B) Design a process to produce a HNO3/H2O solution from methane, water, and air. That is, design a process to produce ammonia, and then use the ammonia to produce nitric acid. Do not simply copy the ammonia process developed in Chapter . The ammonia process can be improved when integrated with the nitric acid synthesis. Specifically,... 

Ammonia from coal gasification has been used for fertilizer production at Sasol since the beginning of operations in 1955. In 1964 a dedicated coal-based ammonia synthesis plant was brought on stream. This plant has now been deactivated, and is being replaced with a new faciUty with three times the production capacity. Nitric acid is produced by oxidation and is converted with additional ammonia into ammonium nitrate fertilizers. The products are marketed either as a Hquid or in a soHd form known as Limestone Ammonium Nitrate. Also, two types of explosives are produced from ammonium nitrate. The first is a mixture of fuel oil and porous ammonium nitrate granules. The second type is produced by emulsifying small droplets of ammonium nitrate solution in oil. 

The two major chemicals based on synthesis gas are ammonia and methanol. Each compound is a precursor for many other chemicals. From ammonia, urea, nitric acid, hydrazine, acrylonitrile, methylamines and many other minor chemicals are produced (see Figure 5-1). Each of these chemicals is also a precursor of more chemicals. 

The main use of rhodium is with platinum in catalysts for oxidation of automobile exhaust emissions. In the chemical industry, it is used in catalysts for the manufacture of ethanoic acid, in hydroformylation of alkenes and the synthesis of nitric acid from ammonia. Many applications of iridium rely on... 

The conjugation in 2,2, 4,4, 6,6 -hexanitroazobenzene (HNAB) (90) is also reflected in its thermal stability (m.p. 220 °C). The synthesis of HNAB from picryl chloride and 2,4-dinitrochlorobenzene is discussed in Sections 4.8.1.2 and 4.8.1.3 respectively. 3,3, 5,5 -Tetraamino-2,2, 4,4, 6,6 -hexanitroazobenzene (149) has been synthesized by an unusual but efficient route which involves the nitration-oxidative coupling of 3,5-dichloroaniline (147) on treatment with nitric acid, followed by reaction of the resulting product, 3,3, 5,5 -tetrachloro-2,2, 4,4, 6,6 -hexanitroazobenzene (148), with ammonia. Both the tetrachloro (148) and tetraamino (149) derivatives exhibit high thermal stability. 

As we learned in Chapters 3 and 4, many inorganic compounds, not just ammonia, are derived from synthesis gas, made from methane by steam-reforming. In the top 50 this would include carbon dioxide, ammonia, nitric acid, ammonium nitrate, and urea. No further mention need be made of these important processes. We discussed MTBE in Chapter 7, Section 4, and Chapter 10, Section 9, since it is an important gasoline additive and C4 derivative. In Chapter 10, Section 6, we presented -butyraldehyde, made by the 0x0 process with propylene and synthesis gas, which is made from methane. In Chapter 11, Section 8, we discussed dimethyl terephthalate. Review these pertinent sections. That leaves only two chemicals, methanol and formaldehyde, as derivatives of methane that have not been discussed. We will take up the carbonylation of methanol to acetic acid, now the most important process for making this acid. Vinyl acetate is made from acetic... 

The most common and important nitrogen-hydrogen compound is ammonia. Because liquid ammonia is a commonly used nonaqueous solvent, it was discussed in Section 5.2.3 and its properties are listed in Table 5.5. Approximately 22 billion pounds of NH3 are used annually, mostly as fertilizer or as the starting material for preparing nitric acid. The Haber process is used for the synthesis of NH3 from the elements ... 

Oxidation is extremely important both from a scientific and a practical point of view. Without oxidation life would not exist. In the chemical industry, too, oxidation is probably the most important process. A major example is the combustion of fossil fuels. This process is usually uncatalyzed, but sophisticated catalytic processes do exist. Examples in the inorganic industry are the oxidation of sulphur dioxide and ammonia in the manufacture of sulphuric acid and nitric acid, respectively. In the petrochemical industry many catalytic synthesis processes are carried out, for example the production of ethylene and propene epoxide, phthalic acid anhydride. An example which has recently also become important is the catalytic combustion of hydrocarbons in flue gases. Table 5.2 gives a list of examples of oxidation catalysis in industry [93]. 

It was not in Mittasch s character to be satisfied with this conspicuous achievement. Parallel to extensive studies on the influence of pressure, temperature, gas composition, catalyst poisons and other factors on the synthesis reaction, he worked toward new types of multi-component catalysts for a great number of other catalytic gas reactions. With his associates Ch. Beck, C. Muller, and Ch. Schneider, he thus discovered efficient catalysts for the water gas reaction, for hydrogenations in the gas phase (among which the synthesis of alcohols and hydrocarbons from carbon monoxide and hydrogen is particularly noteworthy), for the production of nitric acid via the oxidation of ammonia, and for many more industrial processes which are the backbone of large segments of our present chemical industry. 

Due to the low temperatures, the thermal heterogeneous catalytic processes which prevail in the atmosphere are simple hydrolytic reactions (such as the hydrolysis of N2O5 in acidic water droplets to form nitric acid). However, photocatalysis provides more complicated redox reactions (such as ammonia synthesis from N2 and H2O over aerosols containing Ti02). 

Haber process involves direct synthesis from the elements at around 600 K at high pressure and in the presence of a potassium-promoted iron catalyst. Ammonia is used to make nitric acid and other chemicals including many plastics and pharmaceuticals. 

Most of the modem manufacture of nitric acid is done by the catalytic oxidation of ammonia (Ostwald process). Other now outdated processes include the reaction of sodium nitrate with sulfuric acid and direct synthesis from N2 and 02 by the arc process at temperatures in excess of 2,000°C. Once cheap ammonia became available these processes were no longer economical. 

The major part of these catalytic processes is carried out in fixed bed reactors. Some of the main fixed bed catalytic processes are listed in Table 11.1-1. Except for the catalytic cracking of gas oil, which is carried out in a fluidized bed to enable the continuous regeneration of the catalyst, the main solid catalyzed processes of today s chemical and petroleum refining industry appear in Table 11.1-1. However, there are also fluidized bed alternatives for phthalic anhydride— and ethylene dichloride synthesis. Furthermore, Table 11.1-1 is limited to fixed bed processes with only one fluid phase trickle bed process (e.g., encountered in the hydrodesulfurization of heavier petroleum fractions) are not included in the present discussion. Finally, important processes like ammonia oxidation for nitric acid production or hydrogen cyanide synthesis, in which the catalyst is used in the form of a few layers of gauze are also omitted from Table 11.1-1. 

To the double sulfate precipitate, 2 1. of water and 2 1. of 15 iV ammonia solution are added and the mixture is well stirred until the textxire of the precipitate indicates conversion to hydrous oxides (see synthesis 12D). The hydrous oxide precipitate is washed (by decantation) with large volumes of water in a 5-gal. crock until the washings, removed by siphoning, are only very slightly basic. The precipitate is then dissolved in the least amount of concentrated nitric acid. Cerium is next removed from this solution by the bromate method (see synthesis 14), and the remaining rare earths are converted to double magnesium nitrates (synthesis 15). 

In addition to these fairly simple reactions by which we describe compounds dissolving in water, many important reactions take place in water. The chemical equations we write to describe these reactions can be written in any of three forms the choice of equation is based mainly on the context in which the equation is used. We ll illustrate these three types of equations for a reaction that is important in the production of commercial explosives the synthesis of ammonium nitrate from ammonia and nitric acid. 

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