The chemical process by which it is produced is called hydrogenation
Phillips B, Titz B, Kogel U, Sharma D, Leroy P, Xiang Y, Vuillaume G, Lebrun S, Sciuscio D, Ho J, Nury C, Guedj E, Elamin A, Esposito M, Krishnan S, Schlage WK, Veljkovic E, Ivanov NV, Martin F, Peitsch MC, Hoeng J, Vanscheeuwijck P (2017) Toxicity of the main electronic cigarette components, propylene glycol, glycerin, and nicotine, in Sprague-Dawley rats in a 90-day OECD inhalation study complemented by molecular endpoints
Manganese: Needed for bone formation and nutrient metabolism
This temporarily stops saliva production, causing your mouth to dry up in turn