When an alkene reacts with chlorine (Cl2) and water (H2O), the product formed is commonly a haloalcohol, specifically chlorohydrin. This reaction is an example of a halohydrin formation, which involves the addition of a chlorine atom and an -OH group across the double bond of the alkene.
The mechanism of this reaction typically involves the formation of a cyclic chloronium ion intermediate. After the bromonium ion is formed, water acts as a nucleophile and attacks the more substituted carbon atom of the cyclic structure, leading to the opening of the ring. As a result, one carbon will bond with a chlorine atom while the other carbon will bond with a hydroxyl (-OH) group from the water molecule.
For instance, if we take propene (an alkene) as our starting material and react it with Cl2 and H2O, we would end up with 2-chloropropanol. The specific product can vary depending on the structure of the alkene and the reaction conditions, but the overall concept remains the same. Therefore, the reaction of an alkene with Cl2 and H2O generally yields a chlorohydrin as the product.