| http://www.w3.org/ns/prov#value | - Lewis bases which are preferred for the purpose of the invention are those containing one of the following groups: Suitable Lewis bases for the process of this invention may thus be chosen from the group of substituted amides of the general formula R CO.NR .R where R is a hydrogen atom or an alkyl group containing 1 to 5 carbon atoms and R and R which may be the same or different, are each an alky
|
