Nitrogen in metals

Kashima, J., Yamazaki, T. Gas chromatographic determination of nitrogen in metals after inert gas fusion with the aid of silicium. Bull. Chem. Soc. Japan 42, 542 (1969). 

An excellent survey by Albert (21) on the determination of nitrogen in metals with a high melting point gives a great deal of valuable information on the subjects discussed below. 

In his survey of the state of reducing fusion techniques for the determination of nitrogen in metals, Goward (2) concluded in 1965 that this technique was generally held to be unsuitable for the determination of nitrogen... 

Although activation analysis with 14 MeV neutrons can also be used e.g. for the determination of nitrogen in metals (184), using the N(n,2n) N nuclear reaction, this method has been most useful for the determination of oxygen. 

Chemical composition does not generally come into play, except for the case where it is necessary to establish maximum specifications for undesirable compounds such as sulfur, nitrogen, and metals, or even more unusually, certain compounds or families of compounds such as benzene in premium gasolines. By tradition, the refiner supposedly possesses numerous degrees of freedom to generate products for which the properties but not the composition are specified. 

Washing and cleaning agents containing salts of maleic acid—furan copolymers (106) form complexes with alkaline-earth ions. These cleaning compositions do not contain phosphoms or nitrogen and find use in metal, foodstuff, and machine dishwashing products. 

Metallui ical. To prevent reaction with atmospheric oxygen and nitrogen, some metals must be shielded using an inert gas when heated or melted (94). AppHcations in metals processing account for most argon consumption and an important part of helium usage (see AfETALLURGY). 

Ion implantation (qv) direcdy inserts nitrogen into metal surfaces. A carefully poHshed and cleaned metal surface at room temperature in a vacuum (-- 0.133 mPa (l-) m Hg)) can be directly implanted with 80-keV nitrogen ions (10) (see Metal surface treatments, case hardening). In an alternative synthesis, argon ions (Ar ) of 8 keV can be used to ionize gas-phase nitrogen to obtain the same results (17). 

Preparation of phlorogluciaol or its monomethyl ether by reaction of a halogenated phenol with an alkaU metal hydroxide in an inert organic medium by means of a benzyne intermediate has been patented (142). For example, 4-chlororesorcinol reacts with excess potassium hydroxide under nitrogen in refluxing pseudocumene (1,2,4-trimethylbenzene) with the consequent formation of pure phlorogluciaol in 68% yield. In a version of this process, the solvent is omitted but a small amount of water is employed (143). 

Potassium 3-aniinopropylaniide [56038-00-7] (KAPA), KNHCH2CH2CH2-NH2, pX = 35, can be prepared by the reaction of 1,3-diaminopropane and potassium metal or potassium hydride [7693-26-7] (57—59). KAPA powder has been known to explode during storage under nitrogen in a drybox, and is therefore made in situ. KAPA is extremely effective in converting an internal acetylene or aHene group to a terminal acetylene (60) (see Acetylene-DERIVED chemicals). 

Nitrogen dissolves in metallic titanium up to a nitrogen content of 20 atom % (TINq 23)- Above 30 atom % (TINq a cubic titanium nitride phase is stable. 

Pyrrole and alkylpyrroles can be acylated by heating with acid anhydrides at temperatures above 100 °C. Pyrrole itself gives a mixture of 2-acetyl- and 2,5-diacetyl-pyrrole on heating with acetic anhydride at 150-200 °C. iV-Acylpyrroles are obtained by reaction of the alkali-metal salts of pyrrole with an acyl halide. AC-Acetylimidazole efficiently acetylates pyrrole on nitrogen (65CI(L)1426). Pyrrole-2-carbaldehyde is acetylated on nitrogen in 80% yield by reaction with acetic anhydride in methylene chloride and in the presence of triethylamine and 4-dimethylaminopyridine (80CB2036). 

The sorbent of fibrous stmcture has the best kinetic characteristics in relation to noble metals, for which reaching soi ption balance does not exceed 20 minutes. The rate of soi ption balance establishment depends on the form of nitrogen in functional groups of sorbents used and decreases in a line tertiary nitrogen (linear group) > tertiary nitrogen (heterocycle) > quaternary nitrogen. 

The allyl group was used to protect the nitrogen in a /3-lactam synthesis, but was removed in a four-step sequence. Whether a transition-metal-catalyzed isomerization to the enamide followed by hydrolysis is an effective cleavage procedure remains to be tested and warrants further study. ... 

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