Complexation of the pyridine bases in the products from the coking of coal with organic solvents (review)

Abstract

Published data on the complexation of pyridine bases with organic substances of various chemical types are reviewed. Examples of the use of these data for the isolation of individual heterocycles are discussed.Heterocyclic nitrogen compounds in the products from coke-chemical production are present in the form of the light pyridine bases (in coke gas, including pyridine and its methyl-and dimethyl-substituted derivatives, and also a certain amount of quinoline) and heavy bases (quinoline, isoquinoline, methylquinolines, acridine, and a certain amount of pyridines) contained in coal tax.The light pyridine bases are extracted from the gas with sulfuric acid followed by treatment with ammonia to decompose the sulfates. The heavy bases, present in the tar, subsequently get into the various fractions of the tar during rectification. According to data in [1], the fractions containing the light pyridine bases contain 69% of pyridine, ___7.5% of methylpyridines (picolines) and dimethylpyridines (lutidines), >0.6% of trimethylpyridines (collidines), and -12% of quinoline. The coal tar contains [1] 0.2% each of quinoline, isoquinoline, and 2-methylquinoline (quinaldine) and also 0.6% of acridine; the content of pyridine and its methyl derivatives is 0.01-0.02% of each.The bulk of the quinoline bases is concentrated in the naphthalene and absorber fractions of the tar, from which 20-25% is extracted by sulfuric acid and subsequent neutralization of the sulfate solution by a solution of alkali and by ammonia solution (or gaseous ammonia). According to data in [2], in the bases of the naphthalene fraction 61.5% constitutes quinoline, -13% isoquinoline, and 7% quinaldine. In the bases of the absorber fraction the quinoline amounts to 28.4%, the isoquinoline to 13.5%, and the quinaldine to 9.54%. Most of the acridine is concentrated in the anthracene fraction (up to 7-8% of the fraction).In industry [1, 3] during the treatment of light pyridine bases (after removal of the phenols with alkali and dehydration) fractions consisting of pure (up to 98%) pyridine (114-1160C) and pyridine-solvent (120-137"C) are isolated by rectification methods. The pyridine-solvent consists of a mixture of pyridine and methylpyridines. The fraction containing most of the ,~-picoline (___74% of the potential amount)is collected in the range of 128-131~ while the fl-picoline fraction is collected in the range of 138-146~ [2]. (The latter contains 10% of ,~,-picoline, 32% of fl-picoline, 36% of,y-picoline, and >21% of 2,6-lutidine.) The fraction containing the lutidine bases is collected in the range of 158-167~ and the collidine fraction is collected in the range of 168-171~ The heavy pyridine bases (quinoline and its derivatives) are extracted from the tar fractions by washing with dilute sulfuric acid (15-17%) followed by decomposition of the sulfates with ammonia solution.The individual light and heavy nitrogen bases are mainly isolated by chemical methods sometimes in conjunction with rectification [2][3][4]. The most laborious is the isolation o...

Equilibrium study on the reactive liquid–liquid extraction of 4-cyanopyridine with 4-nonylphenol

“…The complexation constant of the cyanide group and the pyridine group with a monomer of NP at 25 1C differ a factor 4 from each other which is in agreement with the difference in reactivity found in literature for the complexation reaction of CP with 4-fluorophenol, where a difference with a factor 3 was obtained (Berthelot et al, 1998). Furthermore, the enthalpy is lower than the threshold of proton exchange which is 45 kJ/mole (Zaretskii, 1997). This indicates that the effect of the hydrogen bond with the pyridine group will not significantly affect the electron-distribution on the aromatic ring and therefore the reactivity of the cyanide group will not change, and vice versa.…”

“…This indicates that the effect of the hydrogen bond with the pyridine group will not significantly affect the electron-distribution on the aromatic ring and therefore the reactivity of the cyanide group will not change, and vice versa. The enthalpies of complexation are within the range of values reported in the literature (Zaretskii, 1997) for the complexation of phenol and pyridine derivatives. The results obtained, and the comparison with the data from the literature verifies the validity of the assumptions made in the development of the model.…”

“…The complexation mechanisms of phenol with pyridine and a variety of substituted forms of pyridines and phenols have been discussed in the literature (Barton et al, 1972;Beezer et al, 1977;Laurence et al, 2003;Zaretskii, 1997). Based on these studies, and on the literature on Lewis basicity (Laurence and Gal, 2009), for the specific case of CP, two hydrogen bonding interactions are possible between the phenolic proton and CP.…”

Thermal Activity in Affinity Separation Techniques Such as Liquid–Liquid Extraction Analyzed by Isothermal Titration Calorimetry and Accuracy Analysis of the Technique in the Molar Concentration Domain

“…Isothermal titration calorimetry (ITC), a technique to measure thermal effects of intermolecular interactions, has been used in several fields, most of them related to biomolecular research or biochemistry. − Protein-related interactions have been studied in the majority of the published work, − followed by synthetic compounds, lipids/micelles, nucleic acids, and carbohydrates . Although ITC was already applied in the 1970s to study interactions and hydrogen bonding between (substituted) phenols and pyridine or picoline, − wide application of ITC to study binding interactions started with the publication of Freire et al in 1990, in which they introduced ITC as an accurate method for this purpose. Ghai et al published in 2012 the last review in a yearly series covering both ITC techniques and applied methods and data analysis.…”

A computational study of substituent effects on the stability and geometry of carbazole‐pyridine complexes

“…In our study, we first identify the preferred geometry of the pyridine:carbazole complex. There have been numerous photophysical studies of the pyridine:carbazole system itself, and annulated and substituted derivatives have been reviewed; but we know of no structural study (either experimental or theoretical) of these systems. This process is repeated for the complex between carbazole and each substituted pyridine: the potential energy surface of each complex is presented as a function of the hydrogen bond distance (N…H) and torsional angle.…”