Catalytic Dehydrogenation and Condensation of Aliphatic Alcohols

Abstract

The melting points of the anhydrides alternate in the opposite sense to those of the acids. Up to valeric the swing is wide but from there on it is small, each odd anhydride melting only about 2°above the mean evens. From heptylic to stearic, the average of the melting points of the anhydrides is 1.2°above the average of the acids. Above valeric the alternation is much smaller for the anhydrides than for the acids.The anhydrides crystallize in leafy plates and are soluble in the usual organic solvents. Limited quantities of the acids, usually one gram or less, prevented the determination of other properties.

Dehydrogenation of methanol to methyl formate over copper catalysts

“…Methyl formate is then formed by reaction between desorbed gaseous formaldehyde and adsorbed formaldehyde fa) (Miyajima and Yasumori, 1966). It has been reported that oxides can promote the condensation reaction of aldehydes (Komarewsky and Coley, 1941) and our observations indicate that, for supported copper catalysts, r2 is very rapid and is the rate-controlling step. This proposal explains the apparent zero-order kinetics and the absence of formaldehyde in the gas phase.…”

Formation of C–C and C–O Bonds and Oxygen Removal in Reactions of Alkanediols, Alkanols, and Alkanals on Copper Catalysts

“…1-Alkanols with n-carbons react on Cu/ZnO/Al 2 O 3 to form esters with 2n carbons and alkanones with 2n or 2n À 1 carbons (2n À 1 alkanones form by CO x loss) via steps that are thought to involve aldol-type species formed via recombinative desorption of the H-atoms that result from CÀH activation steps on basic support sites on Cu surfaces, 30 as also proposed on Cr oxide catalysts. 38 These studies have implicated the essential involvement of support basic sites in CÀC bond formation. We show in the present paper (section 3.2.2.…”

The Dehydrocyclization Reaction.

“…Komarewsky, Riesz, and Thodos (89), working with a chromia-alumina catalyst at 450-475°C., showed that 1-hexanol was converted to benzene, 1-heptanol to toluene, and 1-octanol to a mixture of ethylbenzene, toluene, and xylenes. Repeating this work with pure chromia instead of the alumina-supported material, the reaction was found to take a different course (87), ketones being the final products. A four-step mechanism was suggested: (1) dehydrogenation of alcohol to aldehyde, (2) aldol condensation, (3) loss of carbon monoxide from aldol to give a secondary alcohol, and (4) dehydrogenation of the secondary alcohol to a ketone.…”