Neutral nitrogen compounds

The imides, primaiy and secondary nitro compounds, oximes and sulphon amides of Solubility Group III are weakly acidic nitrogen compounds they cannot be titrated satisfactorily with a standard alkaU nor do they exhibit the reactions characteristic of phenols. The neutral nitrogen compounds of Solubility Group VII include tertiary nitro compounds amides (simple and substituted) derivatives of aldehydes and ketones (hydrazones, semlcarb-azones, ete.) nitriles nitroso, azo, hydrazo and other Intermediate reduction products of aromatic nitro compounds. All the above nitrogen compounds, and also the sulphonamides of Solubility Group VII, respond, with few exceptions, to the same classification reactions (reduction and hydrolysis) and hence will be considered together. 

Type 225-540°C gas oil fraction 50% of nitrogen as neutral nitrogen compounds ... 

Carbazole is a non-basic nitrogen compound, whose removal via hydrotreating is limited by its low reactivity. The removal of nitrogen by hydrotreatment involves a number of steps that take place on the catalyst surface. The weak interaction of neutral nitrogen compounds with catalysts precludes carbazole and its derivatives from being denitro-genated and makes them the most recalcitrant components in HDN of gas oils [308], In fact, it has been found that the nitrogen content of hydrotreated gas oil from Athabasca bitumen was composed primarily of alkyl carbazoles [309],... 

The nitrogen compounds in the heavy oil were shown to be 40% weak base, 14% very weak base, and 46% neutral compounds. Mass spectrometry was used to classify the weak bases as 72% pyridines (one aromatic ring), 24% quinolines (two aromatic rings), and 4% acridines (three aromatic rings). Mass spectrometry combined with infrared analysis and pyrrolic-nitrogen determination were used to classify the very weak base and neutral nitrogen compounds as 7% pyrroles or indoles with either or both of the a and ft positions open and not N-substituted, 22% pyrroles or indoles with substitution on both a and p positions but no N-substitutions, 34% carbazoles with no N-substitutions, and 37% N-substituted carbazoles. 

Acids Bases Neutral nitrogen compounds Saturate hydro- carbons Aromatic hydro- carbons ... 

It was also of interest to establish the fate of acids, bases, and neutral nitrogen compounds on silica and alumina. For this purpose, the acids, bases, and neutral nitrogen compounds isolated on ion exchangers and Fe /clay, respectively, were applied on a silica column. Elution of hydrocarbons with n-pentane yielded 0.29% material, which was separated on alumina into mono + diaromatics (0.1%) and polyaromatics (0.24% ) (Figure 4). Thus, if ion exchangers and the Fe /clay column are omitted, there remains only about 0.8% impurities stemming from acid and base fractions present in the total mono- and diaromatic fractions. 

Separation Procedure. The petroleum asphaltenes were separated into five fractions acids, bases, neutral nitrogen compounds, saturate hydrocarbons, and aromatic hydrocarbons. Acids were isolated using anion-exchange resin, bases with cation-exchange resin, and neutral nitrogen compounds by complexation with ferric chloride adsorbed on Attapulgus clay. The remaining hydrocarbon fraction is separated on silica gel to produce saturate and aromatic hydrocarbon fractions. 

One or more of the hydrogen atoms may be replaced by alkyl groups. Suggest the general formulae for the neutral nitrogen compounds with one, two and three alkyl groups. 

As we will see in Section 16.3, amides are neutral nitrogen compounds that produce an amine and a carboxylic acid when hydrolyzed. Nitro compounds are prepared by the nitration of an aromatic compound. 

However, separation and characterization of the constituents of coal liquids can be performed by compound type (Figure 18.14). This involves utilization of a separation scheme whereupon the entire sample or individual distillation cuts are separated into seven major classes of compounds acids, bases, neutral nitrogen compounds, saturates, monoaromatics, diaromatics, and polyaromatics plus polar compounds. To avoid excessive dilution and use of solvents, a recycle column (Figure 18.15) may be anployed that enables recycling of carrier solvent and accumulation of product in a flask from which fresh solvent is distilled. 

Xie, L. L., Favre-Reguillon, A., Wang, X. X., Fu, X., Pellet-Rostaing, E., Toussaint, G., Geantet, C., Vrinat, M. Lemaire, M. (2008). Selective Extraction of Neutral Nitrogen Compounds Found in Diesel Feed by l-Butyl-3-Methyl-Imidazolium Chloride. Green Chemistry, Vol. 10, No. 5, pp. 524-531, ISSN 1463-9262... 

Geantet, G. Vrinat, M. Lemaire, M. (2008). Selective extraction of neutral nitrogen compounds found in diesel feed by l-butyl-3-methyl-imidazolium chloride. Green Chem., 10, 524-531, ISSN 1463-9270. 

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