Reilly Industries, Inc.

The use of crosslinked poly(vinylpyridine), e.g., Reillex 402 and Reillex 425, as reagents, catalysts, and as supports for metallic catalysts and reagents is described.Preparation of polymeric acylation catalysts of the 4-dimethylaminopyridine type and their effectiveness in esterification and rearrangement are discussed.Process advantages of the catalysts are outlined.

Solid-acid catalyzed vapor-phase reactions forming pyridine and β-picoline, α- and γ-picoline, and 8-methylquinoline (8-MeQ) and 3,8-dimethylquinoline (3,8-DMQ) were examined using labeled feeds (¹³C, ²H) combined with NMR spectroscopy.In the presence of ¹³CH₂O, amorphous silica-alumina (S-A) converted CH₃CHO-CH₂O-NH₃ feed (480 °C) to pyridine containing ¹³C-4 (major) and ¹³C-2 (minor).Co-product β-picoline contained ¹³C-4 and ¹³CH₃ (major) and ¹³C-2 and ¹³C-6 (minor).Replacing ¹³CH₂O by ¹³CH₃OH led to subtle changes in the levels of ¹³C incorporation due to an induction period during which methanol converts to formaldehyde equivalentPyridine and β-picoline formation require a common propenimine intermediate that either condenses with aldehyde/imine species (major route) or undergoes Michael additions (minor route).Use of ¹³CH₃OH and either ZnO/S-A or H⁺-MFI led to similar patterns of ¹³C incorporation, albeit at lower levels than S-A.Reaction of acrolein-D₂O-ND₃ (S-A, 480 °C) gave predominantly 3,5-dideuteriopyridine, 3-methyl-5-deuteriopyridine, and 3-deuteriomethyl-5-deuteriopyridine from imines (CH₂CDCHND, CD₃CHND, and CH₂ND) formed in situ.A slower Bronsted acid-catalyzed reaction of pyridine bases with D₂O incorporates deuterium at C-2,6 ring positions.The CH₃CHO-D₂O-NH₃ reaction (S-A, 440 °C) showed acetaldehyde's carbonyl carbon locates at C-2, C-4, and C-6 positions in both α- and γ-picoline.Addition of either ¹³CH₂O or ¹³CH₃OH to CH₃CHO-CH₂O-ortho-toluidine feed (S-A, 470 °C) gave 8-MeQ containing ¹³C-2 (major) and ¹³C-4 (minor).Byproduct 3,8-DMQ contained ¹³C-2 and 3-¹³CH₃ (major) and ¹³C-4 (minor).Subtle changes in the ¹³C incorporation patterns are once more due to an induction period for ¹³CH₃OH dehydrogenation.The predominant reaction pathway to 8-MeQ and 3,8-DMQ involves N-o-tolyl-methanimine.

A review containing 114 references concerning the syntheses of pyridine and benzopyridine derivatives