2532. NIENBURG, H., AND FRIEDRICHSEN, W. (I. G. Farbenindustrie A. G. "In Auflösung"). [Primary Alcohols.] German Patent 844,891, July 24, 1952 (Cl. 12 o-5.02). Chem. Abs., vol. 47, 1953, p. 5422.

PATENTS

2532. NIENBURG, H., AND FRIEDRICHSEN, W. (I. G. Farbenindustrie A. G. "In Auflösung"). [Primary Alcohols.] German Patent 844,891, July 24, 1952 (Cl. 12 o-5.02). Chem. Abs., vol. 47, 1953, p. 5422.

Treating m-dioxanes with H₂ in the presence of hydrogenation catalysts at elevated temperature (preferably 200°-280°) and pressure (preferably >100 atm.), sometimes in the presence of inert solvents or diluents gives primary alcohols; 2 moles H₂ are consumed per mole of the dioxane derivative, and the cleavage of the dioxane nucleus results in the formation of 1 mole each of MeOH and the higher-molecular alcohol. Heating 4.4-dimethyl-m-dioxane 100 and a Cu-Cr oxide catalyst 5 parts by weight in an autoclave with H₂ at 200 atm. and 260° gives, after removal of the catalyst and distillation, 80-90% iso-AmOH, b. 131°, besides MeOH. Similarly are prepared: 2,3-dimethyl-1-butanol, b. 145°, from 4,4,5-trimethyl-m-dioxane; 2,2,3-trimethyl-1-butanol, b. 156°, from 4,4,5,5-tetramethyl-m-dioxane; BuOH, b. 117°, from 4-methyl-m-dioxane.