👉 In chemistry, "ethylated" refers to a compound that has at least one carbon-carbon double bond between two or more identical atoms. This is called an alkene. The term is often used in the chemical literature to indicate that a substance has undergone a process of being converted into its corresponding alkenes (e.g., ethane, ethylene) by means of a reaction with hydrogen. In other words, if you have a compound that has at least one carbon-carbon double