Uses of Aldehydes and Ketones

Formaldehyde: (i) a 40% aqueous solution, called formalin, is used for preserving biological specimens; (ii) formalin has a hardening effect on proteins and is therefore used in the tanning industry; (iii) formalin is used to manufacture the thermosetting plastic Bakelite, obtained by heating phenol together with formaldehyde. Acetaldehyde: (i) used in silvering mirrors; (ii) its trimer, paraldehyde, is used in medicine as a hypnotic (sleep-inducing agent); (iii) used in the commercial preparation of a number of further organic compounds, including acetic acid and ethyl acetate. Acetone: (i) used as a solvent, and in manufacturing the smokeless gunpowder called cordite; (ii) used as a nail-polish remover; (iii) used in preparing sulphonal, a hypnotic; (iv) used in manufacturing the thermosoftening plastic Perspex. Benzaldehyde: (i) as a flavouring agent; (ii) in perfumes; (iii) in dye intermediates; (iv) as the starting material for synthesising several further organic compounds, such as cinnamaldehyde, cinnamic acid and benzoyl chloride (Sections 12.5.F) …