Cetyltrimethylammonium chloride is a quaternary ammonium salt with long chain, and its molecular formula is CH3(CH2)15N(Cl)(CH3)3. Cetyltrimethylammonium chloride is a commonly used disinfectant. It is commonly used in hair conditioner and shampoo because it has lipophilic long carbon chain and hydrophilic quaternary ammonium ion. It is also a surfactant.