Argon-ammonia complexes

These results are reasonable since B—N is reportedly synthesized by heating the condensation product of orthoboric acid and urea in a stream of ammonia till 1650 C [25]. However, when the pyrolysis were conducted in argon, a black residue was left, indicative of sigmficant amount of carbon in the char. The weight loss was approximately 70%. Initial characterization by XRD of the former residues indicate the presence of a graphite phase, a small amount of BN and other complex B—N—C phases. 

In some instances, it is preferable to use copper scrubbing to remove the last traces of carbon monoxide in the ammonia synthesis gas. This process usually is carried out at pressures in the range of 1000 to 1500 psi, which are intermediate pressures of the high pressure ammonia synthesis feed compressors. The copper liquor is circulated countercurrent to the synthesis gas, picking up the carbon monoxide as a copper ammonium carbonate-carbon monoxide complex and producing a relatively carbon monoxide-free gas. Methane and argon, however, are not removed they pass on with the hydrogen to the ammonia synthesis units. 

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