Reaktionen an Aluminiumoxiden. 5. Mitt.: Umsetzungen von Cyclohexanon an Aluminiumoxid

Abstract

Die Umsetzungen von Cyclohexanon (1) an verschiedenen Aluminiumoxiden wurden bei unterschiedlichen Bedingungen untersucht.Die dabei entstandenen Stoffe wurden durch Vergleichssubstanzen mit Hilfe der DC und GC nachgewiesen. Reactions on Aluminium OxidesThe reactions of cyclohexanone (1) on various aluminium oxides were investigated under different conditions. The resulting products were identified using synthesized compounds by aid of TLC and GLC. Nach Untersuchung der Reaktionen aliphatischer und aliphatisch-aromatischer Ketone' -') an Aluminiumoxiden sollte als cyclisches Keton Cyclohexanon (1) in die Untersuchungen einbezogen werden, woriiber u. W. bisher nicht berichtet wurde. Synthese der VergleichssubstanzenDas bisher unbekannte Aldoladditionsprodukt 1 -(Cyclohexan-1 -olyl)-cyclohexan-2-on (2), das Durr nicht nachweisen konnte4), bildet sich bei Raumtemperatur an saurem, basischem und neutralem Aluminiumoxid. Roginskaja'), der die bimole-1 H.

Self-Condensation of Cyclohexanone Catalyzed by Amberlyst-15. Study of Diffusional Resistances and Deactivation of the Catalyst

“…These results are in accordance with the information reported in the literature about the hydrolysis of the sulfonic groups of this type of resins (Petrus et al, 1981) and about the byproducts formed when the catalyst is a mineral acid (Seebald and Schunack, 1974;Garcia, 1982). Thus, the free sulfuric acid produced in the hydrolysis reaction (R-SO3H + H20 -R-H + H2S04) is a typical homogeneous catalyst which promotes the formation of a lot of byproducts.…”

“…The analysis of samples was made by gas chromatography (column, 8FT 20P DC550 CHROM WAW DMCS 60 80; temperature, 210 °C; carrier gas, nitrogen at 30 cm3/s; reference internal standard, naphthalene at 15%; detector, flame ionization). To perform the chromatographic identification of products of reaction, a synthesis of them was made by following the method proposed by (Seebald and Schunack, 1974). The main organic products of reaction obtained in our operating conditions are as follows: 2-cyclohexenylcyclohexanone (I), 2-cyclohexylidenecyclohexanone (II), 2,6-dicyclohexylidenecyclohexanone (III), 13,15,17-trihydroxyperhydrotriphenylene (IV), 1,12 dodecahydrotriphenylene (V).…”

“…(1) The deactivation was due only to some type of fouling/ poisoning. (2) The self-condensation of cyclohexanone (Seebald and Schunack, 1974;Vegas, 1985) follows the simplified scheme of reaction A + A -* R [+A] -»• P -*• Pi, where A (cyclohexanone) gives product R (mainly, compound I and very small amounts of its isomer, II); some of the product R produced can suffer a series of secondary reactions (in which the reactant A is also involved), giving a family of compounds P (mainly, compounds III-V), which are the most probable materials causing the fouling/poisoning of the resin. (3) The n-order models proposed by Khang and Levenspiel, 1973, treat parallel and series mechanisms of deactivation similar to the ones above described.…”

Catalytic behavior of macroporous resins in catalytic processes with water production. Activation and inhibition effects in the kinetics of the self-condensation of cyclohexanone

“…These kinetic data were fitted, in a first attempt, to a simple model of second-order type, r = kCt? , previously used for fitting kinetic data of the reaction of selfcondensation of cyclohexanone with homogeneous catalysts (Seebald and Schunack, 1974). The fitting of our data to second-order kinetics was nevertheless very poor.…”

“…The reaction network and the product distribution reported in the literature, for other acid catalysts (such as mineral acids), can be very complex or different. The main organic products of reaction are as follows: For chromatography identification purposes, products III, IV, and V were prepared following the method proposed by Seebald and Schunack, 1974. With Amberlyst-15, the selectivity to the most valuable reaction product, 2-cyclohexenylcyclohexanone, was always greater than 98%. Product II was the other most important byproduct.…”