I've been recently looking into alternative biochemistries for life and the environments were these could be found. I already asked a question about how ammonia oceans might form a while back. Today I'm interested in formamide, as according to a book I read recently, CH3NO
is quite a decent solvent.
Formamide is formed by the reaction of hydrogen cyanide with water; both are abundant in the cosmos. Like water, formamide has a large dipole moment and is an excellent solvent for almost anything that dissolves in water, including polyelectrolytes. In particular, formamide is able to dissolve RNA, DNA, and proteins, as well as their precursors. Formamide is not reactive like water. Indeed, many species that are thermodynamically unstable in water with respect to hydrolysis, are stable in formamide. Formamide is itself hydrolyzed by water, meaning that it persists only in a relatively dry environment, such as a desert. Desert environments recently proposed as being potential sites for the prebiotic synthesis of ribose may hold formamide as well. Since formamide boils at ~400 K, a mixture of formamide and water, if placed in the desert, would lose its water over time and end up as a pool of formamide. Within this pool, many syntheses are thermodynamically favorable: polypeptides from amino acids, nucleosides from sugars and bases, nucleotides from nucleosides and inorganic phosphate, and RNA from nucleotides. Indeed, phosphate esters are also spontaneously synthesized. This includes ATP (from ADP and inorganic phosphate), nucleosides (from ribose borates and nucleobases), peptides (from amino acids), and others.
All of this sounds pretty good, but as with the ammonia oceans, I'm not sure how such an environment could form naturally. The book suggest evaporation of water-formamide ponds in deserts a possibility, but I don't know of any formamide lakes in earths deserts. Also the natural formation of hydrogen cyanide seems to be unlikely, at least in the quantaties required.
I think that hot, water poor desert worlds would be the place fore formamide lakes. Due to the fact that formamide will combust in the presence of oxygen, the atmospere sould lack oxygen as well. So should the planet have a nitrogen or carbon dioxide dominated atmosphere?
How would a hot desert planet have to be made up to form lakes of formamide? Is such a planet likely to form? Biological solutions, like blue green alge producing oxygen on Earth, are allowed as long as they are plausible, though I would prefer geochemical solutions. Terraforming as an answer is out.