9.ALDEHYDES, KETONES AND CARBOXYLIC ACIDS

• ALDEHYDES, KETONES AND CARBOXYLIC ACIDS are widespread in plants and animal kingdom. They play an important role in biochemical processes of life. They add fragrance and flavour to nature, for example, vanillin (from vanilla beans), SALICYLALDEHYDE (from meadow sweet) and CINNAMALDEHYDE (from cinnamon) have very pleasant fragrances.

• They are used in many food products and pharmaceuticals to add flavours. Some of these families are manufactured for use as solvents (i.e., acetone) and for preparing materials like ADHESIVES, PAINTS, RESINS, PERFUMES, PLASTICS, FABRICS, ETC.

• In chemical industry aldehydes and ketones are used as solvents, starting materials and reagents for the synthesis of other products. Formaldehyde is well known as formalin (40 per cent) solution used to PRESERVE BIOLOGICAL SPECIMENS AND TO PREPARE BAKELITE (a phenol-formaldehyde resin), urea-formaldehyde glues and other polymeric products.

• ACETALDEHYDE Is used primarily as a starting material in the manufacture of Acetic Acid, Ethyl Acetate, Vinyl Acetate, Polymers and Drugs. Benzaldehyde is used in perfumery and in dye industries. Acetone and ethyl methyl ketone are common industrial solvents. Many aldehydes and ketones, e.g., Butyraldehyde, Vanillin, Acetophenone, Camphor, are well known for their odours and flavours.

• Methanolic Acid Is Used in Rubber, Textile, Dyeing, Leather and Electroplating Industries. Ethanoic acid is used as solvent and as vinegar in food industry. Hexane dioic Acid is used in the manufacture of nylon 6, 6. Esters of benzoic acid are used in perfumery. Sodium benzoate is used as a food preservative. Higher fatty acids are used for the manufacture of soaps and detergents.

10. AMINES

• Amines constitute an important class of organic compounds derived by replacing one or more hydrogen atoms of ammonia molecule By Alkyl or Aryl Group. In nature, they occur among proteins, vitamins, alkaloids, and hormones.

• SYNTHETIC EXAMPLES INCLUDE POLYMERS, DYESTUFFS AND DRUGS. Two biologically active compounds, namely adrenaline and ephedrine, both containing secondary ammo group, are used to increase blood pressure. Novocain, a synthetic amino compound, is used as an anesthetic in dentistry. Benadryl, A Well-Known Antihistaminic Drug also contains tertiary amino group.

• Quaternary Ammonium Salts are used as surfactants. Diazonium salts are intermediates in the preparation of a variety of aromatic compounds including dyes.