Why do different alcohols have different effects on the brain?
As the chain length of the alcohol increases, it becomes more hydrophobic. This would make it easier for them to insert into membranes and hydrophobic pockets of proteins. This could interfere with the protein function. Hydrophobic molecules also tend to be harder to eliminate than shorter molecules and can accumulate in fatty tissues, including the brain. Longer chains can also be metabolized into a greater number of products simply because there is more to metabolize. And sometimes seemingly innocuous compounds can be metabolized into very toxic substances, such as n-Hexane, which can be converted to a molecule with an epoxide on each end. The epoxides can cross-link proteins, particularly in neuron axons.