Ibn Al Razi a physician and a polymath had a problem on his hands. Germs and loads of them invading where he practiced as a physician. This was making his patients sick; he could not see the microscopic culprits’ bacteria and viruses. His keen observations led to him to the conclusion to find a sanitizer. At the time non existed other than washing surfaces.
Alrazi was determined to find a solution and probed all known literature and methodologies. With the help of earlier findings by another master Alchemist Jabir ibn Hayyan, mainly through his experimentation with different elements. Mr. Alrazi had a clear path to carry out his hypothesis of distilling alcohol to make a high concentration and use it as a disinfectant.
The technology available was a laboratory contraption, an Alembic. By heating a solution inside the Alembic and allowing the vapours to rise then cool down. An extract of highly concentrated alcohol was obtained.
Alcohol was always found in nature in low concentrations in fruits, and by default this was not an invention but rather a discovery.