There are many chemical substances which play important role in our daily life such as medicines, drugs, food preservatives, soaps and detergents etc. Let’s discuss few of them which are highly useful for human beings. Let’s start with drugs which are externally administered substances. They modify the chemical reactions which occur in the living body. They are specific molecules which show a particular pharmacological or physiological action on an organism. They are medicines with complete formulation of the means of administering the drug to a patient. For example analgesics or anti-inflammatory agent are drugs which are used for the reduction of pain. Some common examples of analgesics are aspirin (C9H8O4), paracetamol (C8H9NO2) and ibuprofen (C13H18O2).
All these molecules contain the aromatic ring with 6 carbon atoms that is benzene. We know that benzene is one of the simplest aromatic compounds. Now days, the modern pharmaceutical industry is completely bases on herbs and other traditional ways. For example willow herb can be extracted from seeds and leaves of the willow tree. It is generally used for the treatment of headaches and as pain relaxation in childbirth. The ingestion of it hydrolyses it and gives salicylic acid from the precursor molecules. The German chemist Hoffmann prepared aspirin by the chemical modifications of salicylic acid in 1890. Similarly the oil of winter green also extracted from plants.
The chemical name of oil of wintergreen is methyl ester of salicylic acid. It also has similar medicinal effects. Aspirin is another important drug which is sparingly soluble in water. It is prepared by the neutralisation the carboxylic acid in the presence of bases such as NaOH and forms soluble sodium salt of the acid. Other useful chemicals are food additives, packing materials, food preservatives etc. Food additives provide colour, flavour and sweetness to the food materials. Some of the food additives are harmful for human health such as some of these chemicals show carcinogenic effect. The coloured food materials are attractive and easy the consumer’s perception. We can observe the composition of food colouring with the help of paper or thin layer chromatography. The use of flavours in food stuff makes the food tastier and less bland. Preservatives are generally used to preserve food for long time. Microorganisms such as bacteria or fungi can easily oxidise and causes rancidity of food. The addition of preservative avoids the growth of these microorganisms.
The use of antioxidants prevents the oxidation process of oils or fats in the presence of oxygen or air. Similarly addition of sweeteners counters the bitterness of food and adds special taste to the food. The addition of emulsifiers and stabilisers keeps all ingredients of mixture together and also protect the separation of fatty components from water based components. Processed foods such as soft drinks, topping powders, mayonnaise, cakes, biscuits, extruded snacks, peanut butter, chocolate coatings, chewing gum, margarine, breakfast cereals, coffee whiteners, ice-cream, mousses, dried potato and bread contain emulsifiers. Use of emulsifier provides a better texture and appearance to food such as salad dressings, paints and ice creams.