[11C]Formaldehyde revisited: considerable concurrent [11C]formic acid formation in the low-temperature conversion of [11C]carbon dioxide into [11C]formaldehyde

The reduction of [11C]carbon dioxide with lithium aluminium hydride in diethyl ether at temperatures ranging from −56°C to 19°C was studied. In contrast to what others have reported, considerable amounts of [11C]formic acid were found at all studied temperatures.