The present invention relates to monosubstituted oxalic acid amides of the general formula (I)
[A]+ [O-C(O)-C(O)-X]- (I)
wherein the meaning is for
[A]+ a cation made from an organic moiety A having a formally positively charged heteroatom selected from the group consisting of nitrogen, phosphorus and sulfur and
X is the group -NRaRb, wherein Ra and Rb are the same or different and are independently from each other hydrogen or a C1 to C30 organic residue with the proviso that at least one of Ra and Rb is a C1 to C30 organic residue.