Microwave assisted phosgenation – alcoholysis using triphosgene
Abstract
The microwave assisted reaction engineering of the phosgenation of alcohols with triphosgene as a safe-to-handle phosgene substitute was investigated. The phosgenation of n-butanol was carried out in the homogeneous phase as a one-pot reaction, and in a two-chamber reactor in which freshly produced phosgene gas was bubbled through the educt solution. New catalysts such as phenanthroline, benzyltriethylammonium chloride (BTAC), and the ionic liquid 1-ethyl-2,3-dimethylimidazolium-bis-trifluoromethanesulfoneimide (PW1022) were successfully employed for the decomposition of triphosgene, alone or in combination with activated charcoal, which acted as a microwave absorber. In another experimental series, the reaction of a wide range of alcohols (isopropanol, n-butanol, tert-amyl alcohol, 2-butoxy-ethanol, cyclohexanol, benzyl alcohol, 1-phenyl alcohol, n-octanol) with triphosgene was investigated for two different microwave set-ups.