Synthesis of pyridine and methylpyridines over zeolite catalysts

Abstract

The synthesis of pyridines has been performed by a multi-component reaction of ethanol, formaldehyde, and ammonia in the presence of H-Beta, H-ZSM-12, and H-ZSM-5 zeolite catalysts. The maximum activity in the reaction is revealed by H-Beta zeolite; the conversion of ethanol induced by it reached 70% (400°C, 2 h -1 ). The main products of the reaction in the presence of H-Beta and H-ZSM-5 zeolites are pyridine and picolines; on H-ZSM-12 picolines and lutidines. Thus, the results of the studying the effect of reaction parameters are showed that the yield of lutidine and heavy products increases with the increase of the temperature (from 200 to 400°C) and the decrease of the weight hourly space velocity (from 10 to 2 h -1 ).

Complementary host behaviour of three anthracenyl-derived roof-shaped compounds in mixed pyridines

“…2 The pyridines may also be synthesized on an industrial scale by means of the condensation between formaldehyde, acetaldehyde and ammonia, which, once more, affords a mixture of pyridine and alkylated pyridines. 3,4 As a result of these product mixtures, extractions and distillations are subsequently required in order to furnish each one with high enough purity for further applications, and herein lies the challenge: the MePy isomers boil within a narrow temperature range (2MePy boils at 129, 3MePy at 144 and 4MePy at 145 °C), while the boiling point of Py is much lower (116 °C) (and so is readily recovered from the pyridine bases through distillation). 5…”

“…2 The pyridines may also be synthesized on an industrial scale by means of the condensation between formaldehyde, acetaldehyde and ammonia, which, once more, affords a mixture of pyridine and alkylated pyridines. 3,4 As a result of these product mixtures, extractions and distillations are subsequently required in order to furnish each one with high enough purity for further applications, and herein lies the challenge: the MePy isomers boil within a narrow temperature range (2MePy boils at 129, 3MePy at 144 and 4MePy at 145 °C), while the boiling point of Py is much lower (116 °C) (and so is readily recovered from the pyridine bases through distillation). 5 Alternative separation strategies for, more especially, the aromatic positional isomers, are attractive in the chemical industry since many of these compounds have such similar physical properties that they consequently render fractional distillations and crystallizations ineffective, as was alluded to for the pyridines (especially 3MePy and 4MePy, where the boiling points are nearly identical).…”

Behavior of the Wheel-and-Axle Host Compound 1,4-Bis(diphenylhydroxymethyl)benzene in Mixed Pyridyl Guest Solvents

“…More convenient and effective separation procedures therefore remain attractive, and host–guest chemistry may serve as an alternative avenue toward purifying these pyridines. These aromatic nitrogen-containing solvents often present as mixtures when recovered from the coke oven after coking coal at extremely high temperatures or when being synthesized by employing various catalytic approaches − and hence the requisite separation procedures if pure compounds are required for further application.…”

The behaviour of tricyclic fused host systems comprising seven-membered B-rings in mixed pyridines

“…As examples, these nitrogen-containing liquids are used as building blocks towards the manufacture of dyes, textiles, agrochemicals, adhesives, pesticides and herbicides, and also serve as both solvents and bases in numerous chemical transformations. 1–3…”

“…As examples, these nitrogen-containing liquids are used as building blocks towards the manufacture of dyes, textiles, agrochemicals, adhesives, pesticides and herbicides, and also serve as both solvents and bases in numerous chemical transformations. [1][2][3] While these methylated pyridines may be recovered from the coke oven after coking coal at elevated temperatures, 4 they may also be synthesized on a commercial scale by means of a number of different strategies. One approach employs the gas phase methylation of pyridine (PYR) in the presence of various zeolites including mordenite, ZSM-22 and zeolite beta, and others.…”