Synthesis of ammonia

Arthur L. Weber (1998), now working at the Seti Institute of the Ames Research Center at Moffett Field, reports the successful synthesis of amino acid thioesters from formose substrates (formaldehyde and glycolaldehyde) and ammonia synthesis of alanine and homoserine was possible when thiol catalysts were added to the reaction mixture. On the basis of his experimental results, Weber (1998) suggests the process shown in Fig. 7.10 to be a general prebiotic route to amino acid thioesters. 

Figure 4.31. Comparison of calculated and experimental rates for ammonia synthesis of a nanoparticle Ru catalyst under industrial conditions. Adapted from Ref. [58].

Kvaerner Process Technology Amines, Isopropyl Acetone/isopropanol and ammonia Synthesis of monoisopropylamine at hijji-purity 6 1992... 

In the following sections some aspects of (potential) applications of sc-fluids in the fine chemical industry with respect to product separation/purification and catalytic reactions are discussed. Earlier industrial applications of supercritical fluid reactions, for example the Haber-Bosch process for the synthesis of ammonia, synthesis of methanol from hydrogen and carbon monoxide, or the polymerization of ethene will not be discussed. An extensive overview on the use of sc-fluids in the synthesis of bulk chemicals is given in the book edited by fessop and Leitner [12],... 

In addition to this electronic interaction between finely divided ruthenium metal particles and cerium hydride, a hydrogen spillover was also proposed to explain the high activity for ammonia synthesis of these catalysts. Since hydrogen in the octahedral sites of CeH2+.t is desorbed at 420°C, atomic hydrogen is certainly present at the temperature of ammonia synthesis (450-550°C). Therefore spillover of atomic hydrogen at the hydride/ transition metal interface could occur. 

FIGURE 6.2. The specific reactivity for ammonia synthesis of various Fe singlecrystal surfaces at 20 atm and 798K [10]. 

Table 2. Composition and activity in ammonia synthesis of used K-C-Fe/AljOj catalysts, t = 350 C S.V. 5000 h atmospheric pressure.

Imm S, Bahn S, Beller M et al (2011) Improved ruthenium-catalyzed amination of alcohols with ammonia synthesis of diamines and amino esters. Angew Chem Int Ed 50(33) 7599-7603... 

Fig. 3.31 Activity pattern for ammonia synthesis of reduced catalyst with iron oxides as precursor...

Fig. 3.74 The rate of ammonia synthesis of different iron surfaces showing that the addition of aiumina and annealing in water and oxygen produce an active snrface on the ieast active (110) face of iron ...

However, the model of ammonia synthesis of Stoltze nd Norskov shows that even if N is the most abundant reaction intermediate at typical reaction condition, N, NH, NH2, H, and NH3 are all more abundant than. This explains why a Langmuir-Hinschelwood expression with only one surface intermediate is not particularly successful [396, 645]. 

Sodium/liq. ammonia Synthesis of amines from oximes... 

Haber process The process for the direct synthesis of ammonia from and Hj over a catalyst. 

C, b.p. 205°C, forms monohydrate m.p. 58°C. Prepared from diacetoneamine and propanone or by passing NH3 gas into pro-panone containing fused CaCl2. Decomposes to phorone and ammonia, reduced to lelra-melhyl-3-hydroxypiperidine. Used in the synthesis of benzamine hydrochloride. 

The technique of low-energy electron diffraction, LEED (Section VIII-2D), has provided a considerable amount of information about the manner in which a chemisorbed layer rearranges itself. Somotjai [13] has summarized LEED results for a number of systems. Some examples are collected in Fig. XVlII-1. Figure XVIII-la shows how N atoms are arranged on a Fe(KX)) surface [14] (relevant to ammonia synthesis) even H atoms may be located, as in Fig. XVIII-Ih [15]. Figure XVIII-Ic illustrates how the structure of the adsorbed layer, or adlayer, can vary wiA exposure [16].f There may be a series of structures, as with NO on Ru(lOTO) [17] and HCl on Cu(llO) [18]. Surface structures of... 

The addition of potassium to Fe single crystals also enliances the activity for ammonia synthesis. Figure A3.10.19 shows the effect of surface potassium concentration on the N2 sticking coefficient. There is nearly a 300-fold increase in the sticking coefficient as the potassium concentration reaches -1.5 x 10 K atoms cm ... 

Strongin D R, Carrazza J, Bare S R and Somoqai G A 1987 The importance of Cj sites and surface roughness in the ammonia synthesis reaction over iron J. Catal. 103 213... 

Bare S R, Strongin D R and Somoqai G A 1986 Ammonia synthesis over iron single crystal catalysts—the effects of alumina and potassium J. Phys. Chem. 90 4726... 

Glycine is the simplest member of a large and very important class of compounds, the a-amino-carboxylic acids. TTiere are many different methods available for the synthesis of amino-acids, but glycine can be readily prepared by the action of an excess of ammonia on chloroacetic acid ... 

Synthesis of Acetamide from Ethyi Acetate and Ammonia... 

Several substituted cyclohexane derivatives may also be obtained by the reduction of a benzenoid precursor. Partial reduction of resorcinol, for example, and subsequent methyla-tion yields 2-methylcyclohexane-I,3-dione, which is frequently used in steroid synthesis (M.S. Newman, 1960 see also p. 71f.), From lithium-ammonia reduction of alkoxybenzenes l-alkoxy-l,4-cyclohexadienes are obtained (E.J. Corey, 1968 D). 

A similar reaction in which ammonia and carbon dioxide are heated under pres sure IS the basis of the industrial synthesis of urea Here the reactants first combine yielding a salt called ammonium carbamate... 

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