Ammonia as the nitrogen source

Urea Process. In a further modification of the fundamental Raschig process, urea (qv) can be used in place of ammonia as the nitrogen source (114—116). This process has been operated commercially. Its principal advantage is low investment because the equipment is relatively simple. For low production levels, this process could be the most economical one. With the rapid growth in hydrazine production and increasing plant size, the urea process has lost importance, although it is reportedly being used, for example, in the People s RepubHc of China (PRC). 

This enzyme [EC 4.1.3.27] catalyzes the reaction of chorismate with glutamine to generate anthranilate, pyruvate, and glutamate. In certain species, this enzyme is part of a multifunctional protein together with one or more other components of the system for the biosynthesis of tryptophan (Le., indole-3-glycerol-phosphate synthase, anthranilate phosphoribosyltransferase, tryptophan synthase, and phosphoribosylanthranilate isomerase). The anthranilate synthase that is present in these complexes has been reported to be able to utilize either glutamine or ammonia as the nitrogen source. However, it has also been reported that when anthranilate synthase is separated from this complex, only ammonia can serve as a substrate. 

Consider next the fermentation of some nonnitrogenous, but otherwise unspecified, substrate (for example, a sugar such as glucose) in aqueous solution with dissolved ammonia as the nitrogen source to produce average biomass, carbon dioxide, and water. On a carbon mole basis, this reaction is... 

In Illustration 15.9-3 the yeast Saccharomyces cerevisiae was produced anaerobically (without oxygen) from the fermentation of glucose using ammonia as the nitrogen source. In that illustration it was found using the atom balance that... 

When the bacterium Zymomonas mobilis is used to produce ethanol from glucose in an anaerobic process with ammonia as the nitrogen source, it is found that bacteria biomass is produced to the extent of 0.06 C-moles per C-mole of glucose. The biomass has an elemental composition of CHi.sObjNo. . What are the fractional conversion of glucose to ethanol (on a C-mole basis), the amount of ammonia used, and the amount of carbon dioxide produced per C-moIe of glucose consumed ... 

Various different substrates are being considered for the biochemical production of 1,3-propanedioI (see previous problem) using dissolved ammonia as the nitrogen source. Determine the maximum amount of... 

The extensive work carried out by Beller in recent years has contributed to the field with a series of interesting examples, most of them based on the system palladium/di-1 -adamantyl- -butylphosphine (BuPAdj). Thus, they reported the use of ammonia as the nitrogen source for the palladium-catalyzed aminocarbonylation of aryl halides, providing a straightforward method to prepare primary amides with excellent applicability and functional group tolerance [4]. In the same group, the first carbonylative C—H activation reactions of heteroarenes to form diaryl ketones 4 were developed [5], A series of nonpreactivated heteroarenes 3 (oxazoles, thiazoles, and imidazoles) were successfully carbonylative coupled to a wide range of aryl iodides (Scheme 3.2). To avoid the formation of the noncarbonylative... 

When primary amines are desired, the reaction is carried out as just described, using ammonia as the nitrogen source. 

Imines do not have to be separately prepared and isolated for subsequent reduction. A mixture of a carbonyl compound and ammonia or the appropriate amine reacts in the presence of hydrogen gas and a metal catalyst. An imine forms initially, and it is reduced to an amine. The overall process is called reductive amination. Primary amines are prepared using ammonia as the nitrogen source. 

More recently, primary amines were prepared from methyl glycosides in a single synthetic step by means of a domino Bernet-Vasella reaction/reductive amination using ammonia as the nitrogen source [30]. The protocol involved the overnight... 

Equations and thermodynamic changes at 298.15 K and 1 atm representing the growth of Saccharomyces cerevisiae anaerobically on glucose and aerobically on glucose, ethanol, and acetic acid, with ammonia as the nitrogen source ... 

Other PK variations include microwave conditions, solid-phase synthesis, and the fixation of atmospheric nitrogen as the nitrogen source (27—>28). Hexamethyldisilazane (HMDS) is also an excellent ammonia equivalent in the PK synthesis. For example, 2,5-hexanedione and HMDS on alumina gives 2,5-dimethylpyrrole in 81% yield at room temperature. Ammonium formate can be used as a nitrogen source in the PK synthesis of pyrroles from l,4-diaryl-2-butene-l,4-diones under Pd-catalyzed transfer hydrogenation conditions. 

A similar reaction with ammonia as a nitrogen source at 1100°C has a much higher deposition rate owing to the high reactivity of the monatomic nitrogen released in the ammonia decomposition. 

This enzyme [EC 6.S.4.2], also referred to as UTPiam-monia ligase, catalyzes the reaction of UTP with ATP and ammonia (or glutamine) to produce CTP, ATP, and orthophosphate (and glutamate if glutamine had been used as the nitrogen source). 

Small amounts of ammonia are added when needed as the nitrogen source for the bacteria in industrial and municipal biological waste treatment systems. Other industrial plants use minor amounts of ammonia to neutralize acid in plant... 

The earliest synthesis of imidazole was achieved by Debus from glyoxal, formaldehyde and ammonia (Scheme 70), and many of the classical methods of Imidazole synthesis were based on this general type of reaction. Initially, most syntheses utilized a-diketones, but in the 1930s it was shown that a-hydroxy ketones could serve equally well provided that some oxidizing agent (e.g. ammoniacal copper(II) acetate, citrate or sulfate) was incorporated in the reaction mixture. Further improvement used ammonium acetate in acetic acid as the nitrogen source. 

Many of the classical methods grew out of the earliest synthesis of imidazole, which was achieved in 1858 by Debus [1] when he allowed glyoxal, formaldehyde and ammonia to react together. Although the earliest modifications of this method used a-diketones or a-ketoaldehydes as substrates [2, by the 1930s it was well established that a-hydroxycarbonyl compounds could serve equally well, provided that a mild oxidizer (e.g. ammoniacal copper(ll) acetate, citrate or sulfate) was incorporated [3. A further improvement was to use ammonium acetate in acetic acid as the nitrogen source. All of these early methods have deficiencies. There are problems associated with the synthesis of a wide range of a-hydroxyketones or a-dicarbonyls, yields are invariably rather poor, and more often than not mixtures of products are formed. There are, nevertheless, still applications to the preparation of simple 4-alkyl-, 4,5-dialkyl(diaryl)- and 2,4,5-trialkyl(triaryl)imidazoles. For example, pymvaldehyde can be converted quite conveniently into 4-methylimidazole or 2,4-dimethylimidazole. However, reversed aldol reactions of pyruvaldehyde in ammoniacal solution lead to other imidazoles (e.g. 2-acetyl-4-methylimidazole) as minor products [4]. Such... 

For many years, CVD TiN has been used for wear-and erosion-resistant applications. TiN has a low coefficient of friction and is relatively chemically inert, which makes it attractive for this purpose. In addition, the coating of stainless steel with TiN is of interest for increased biocompatibility of surgical tools and human implants. The reactions used to deposit TiN are very similar to those used for the deposition of Ti02. TiCU is the most common titanium precursor. Nitrogen or ammonia can be used as the nitrogen source. 

The reactions used to form boron nitride have been studied extensively, and several are used in practice. Metal halides are the most common boron precursors, and ammonia typically serves as the nitrogen source ... 

Many of these reactions are variations of the classical methods which reacted a-dicarbonyls or a-hydroxycarbonyls with ammonia. Alkaline cleavage of the a-dicarbonyls provides the C-2 fragment. These reactions naturally tend to form mixtures, and yields are often low. Nevertheless, they still have applications. Modifications have included the use of formamide as the nitrogen source. These reactions were discussed in detail in CHEC-I and so only some late examples are covered in this chapter. A novel synthesis of acyloins (55-95%) may increase the scope of these approaches <94SC367>. 

A high concentration of a source of nitrogen is necessary to produce glutamate and ammonium gas, its solution, an appropriate inorganic salt, or urea are used in actual production. Inorganic salts like potassium phosphate and ferric and manganese salts are also important. The pH of the medium is controlled at 7 - 8 by the addition of ammonia gas or solution, and the added ammonium ions are also used as the nitrogen source. 

Lacroute wanted to supplement mutants blocked in the first step of uracil biosynthesis, aspartate transcarbamylase (ura2), with the product of the reaction, ureidosuccinate (USA). He found that when ammonia was supplied as the nitrogen source, USA was not taken up, but that on... 

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