Thioacetic acid is an organosulfur compound with the molecular formula CH3COSH. It is a yellow coloured liquid with a strong thiol-like odor. It is used in organic synthesis for the introduction of thiol groups in molecules Thioacetic acid is an organosulfur compound with the molecular formula CH3COSH. It is a yellow coloured liquid with a strong thiol-like odor. It is used in organic synthesis for the introduction of thiol groups in molecules Thioacetic acid is prepared by the reaction of acetic anhydride with hydrogen sulfide: It has also been produced by the action of phosphorus pentasulfide on glacial acetic acid, followed by distillation.