CHEMISTRY IN EVERY DAY LIFE

Introduction

     Study of chemistry is important for the simple reason that, many chemicals find applications in almost all aspects of our daily life.

Chemotherapy

     Chemotherapy is the use of chemicals or drugs to selectively destroy infectious micro-organisms without destroying the live tissues or the host. Paul Ehrlich called drugs as magic bullets and the first milestone of his research was the discovery of Salvarsan for curing syphilis, in 1909. In 1935, Gerhard Domagk, administered a dose of a dye called prontosil (inhibits the growth of streptococci bacteria) to cure his daughter's fever. This laid the foundation for modern chemotherapy and got a Nobel Prize for medicine for Domagk in 1939. Ernest Fourneau, a French scientist in 1936 proved that in the human body, prontosil breaks down to give sulphanilamide. Sulphanilamide is the actual active agent that inhibits streptococci. This study led to the discovery of sulpha drugs and from there on growth of chemotherapy has reached amazing heights.

Analgesics

     Narcotics
     These analgesics are mainly opium and its products. Some examples are morphine, codeine and heroin. They are effective analgesics but cause addiction. Over dosage can cause sleep and unconsciousness.
       

Tranquillisers

     Tranquillisers reduce anxiety and tension. They are of two types:
     a) Sedatives
     b) Antidepressants (mood elevators or Pep pills)

Antiseptics and Disinfectants

     Sterilization is the process of complete elimination of micro-organisms. The chemicals used for sterilization are classified as:
     a) Antiseptics
     b) Disinfectants

Anti-fertility Drugs

     With global population growing by the day, birth control has become essential. There are drugs that control ovulation and if regularly consumed, function as effective contraceptives. Some examples of birth control pills are orthonovum and Enovid. Orthonovum is a mixture of norethindrone (17a - ethynyl - 19 - nortestosterone) and mestranol (17a - ethynyl - 3 - methoxy - 1,3,5(10), estratriene - 17 b - ol). Envoid is a mixture of norethynodrel (17 a - ethynyl - 17 - b - hydroxy - 5 (10)-estern - 3-one) and mestranol.

Antacids

     Tension and mental stress escalate the level of acid in bile juice. This hyperacidity can be combated using bases like calcium carbonate, magnesium hydroxide or aluminium hydroxide in the form of tablets or aqueous suspensions. These react with hydrochloric acid in the stomach and neutralize it partially. Gelusil and Digene are two examples of antacids.

Antihistamines

     Histamine is naturally present in almost all body tissues. When the human body meets substances causing allergies, histamine is released. For e.g., when a person is suffering from hay fever, histamine is released. Amines that are used as drugs to control the allergy caused by histamines are calledAntihistamines.

Antibiotics

     They are produced by micro-organisms that are toxic to other micro organisms. Alexander Fleming in 1920 found that bacteria donot flourish in nutrient agar surrounded by the fungus Penicillium notatum westling. He found that this fungus produces an antibiotic called penicillin. There are many varieties of pencillin with the empirical formula C₉H₁₁O₄SN₂R.

Dyes - Meaning and Characteristics

     Colored substances used for dyeing fabrics are called dyes. A true dye must:
     * Have a suitable color
     * Be able to attach itself to the material from solution or be capable of being fixed on it
     * Be fast to light and washing when fixed. For this it must be resistant to water, acid and alkali

Dyes - Chromophores

     Unsaturated groups or groups with multiple bonds that impart color to the organic compound are called chromophores. Examples are the nitro, the nitroso and the azo groups.

Auxochromes as Dyes

     Auxochromes (salt forming groups like hydroxyl, amino) do not impart color to the chromogens in the absence of chromophores. However, when the chromogen has a chormophore, the auxochrome deepens the color of the chromogen. It is also used to make the chromogen a dye.

Classification of Dyes Based on Chemical Structure

     Oldest synthetic dyes do not have much commercial importance.
     

Classification of Dyes Based on Application

     Direct or Substantive Dyes
     These can be directly applied by immersing the cloth in a hot solution of the dye in water. They can be again classified into acid and basic dyes.
     Acid dyes are sodium salts of sulphonic acid and nitrophenols. They are used for dyeing animal fibers (wool and silk) but not vegetable fibers (cotton). The dye solution is acidified with sulphuric or acetic acid.
     Basic dyes are salts of color bases with hydrochloric acid or zinc chloride. They can directly dye animal fibers. They need a fixing agent called mordant (tannin) to dye vegetable fibers. These are used for dyeing silk and cotton.

Methyl Orange as a Dye

     This belongs to the azodyes. It is prepared by coupling diazotized sulphanilic acid with dimethylaniline.
     

Aniline Yellow (Amino azobenzene) as a Dye

     This is another azodye and has little value as a dye. This is because it is sensitive to acids. This is the simplest basic azo dye. This can be obtained by coupling benzene diazomium chloride with aniline.
     
     

Malachite Green as a Dye

     Belongs to the triphenyl methane dyes. Prepared by condensing 1 molecule of benzaldehyde with 2 molecules of dimethylaniline (1:2 ratio) in presence of con H₂SO₄. The leuco base is oxidised with lead dioxide and HCl to color base which further reacts with HCl to give the dye.

Natural Dyes (Alizarin and Indigo)

     Dyes can also be classified as natural and synthetic dyes. Compounds extracted from plants are called natural dyes. These were used in olden days to color fabrics. Alizarin (red) and indigo (blue) are two examples. Synthetic dyes came into being to provide more varieties of colors.

Chemicals in Cosmetics

     Chemicals find great use in cosmetics. Creams like cleansing creams, cold creams, bleaching and vanishing creams are prepared synthetically from chemicals. Perfumes, talcum powders and deodorants are also some other cosmetic substances that are obtained from chemicals. Lipsticks, nail polish and hair dyes also are chemical substances.

Perfumes

     Perfumes have pleasant smell due to the esters used in their synthesis.

Carbon Fibres

     Carbon fibers are made of long chain of carbon atoms.
     They are got from synthetic or regenerated fibers by heating them in the absence of oxygen. These fibers on heating decompose to produce carbon fibers.

Ceramics

     Besides being useful, chemicals find use in artifacts as well. Ceramics, paints, varnishes, glass, cement are various other useful substances that contain various chemicals as their components. Construction industry is the major beneficiary of such substances.

Micro Alloys

     Micro alloyed steels are intermediate carbon steel alloys with 0.3 to 0.6% carbon content. They also include vanadium, columbium (niobium), titanium and so on. These micro alloys are tougher than higher alloys. Their enhanced strength is due to the precipitation hardening reaction where nitrides or carbonitrides are formed in steel. Therefore, nitrogen level control is a key factor.

Importance of Chemicals in Food

     Actually speaking, natural food substances are various forms of chemicals. For e.g., rice is a carbohydrate. Fruits contain carbohydrates and acids like citric acid. Vegetables contain proteins (amino acid blocks) and vitamins. Besides these, chemicals are also used as preservatives for canned or bottled food items to increase their shelf life. Chemicals also find use as edible colors and artificial sweetening agents.

Chemical Preservatives

     Chemicals added to food materials to prevent the growth of micro organisms or prevent spoilage and to increase their shelf life are called preservatives.

Artificial Sweetening Agents

     For diabetic patients, sugar cannot be used as a sweetening agent. Artificial sweetening agents that are non-nutritive in nature are used as substituents for sugar (specially in soft drinks). Examples are saccharin (500 times sweeter than sucrose) and cyclamates.

Edible Colours and Flavours

     Food colors are used in ice creams, dairy products, sweet meat, soft drinks, confectionery, etc. These colors are also used in oral medicines like capsules, tablets, syrups and liquids to improve their appearance. Some of the primary colors are water soluble. They are: quinoline yellow, tartrazine, sunset yellow FCF, erythrosine, poncean 4R, carmoisine, amaranth and brilliant blue.

Soaps and Detergents

     Soaps are sodium or potassium salts of higher fatty acids like stearic, palmitic and oleic acids. Fatty acids are organic acids that have more than sixteen carbon atoms in their molecular structure. The sodium soaps are called hard soaps and the potassium soaps are known as soft soaps. Soaps are obtained from oils and fats. For e.g., tristearin is got from beef and mutton tallow, tripalmitin from palm oil and triolein from lard (pig fat), olive oil and cotton seed oil. In India, soap is commonly got from coconut, groundnut, til and mahua oils.

Synthetic Detergents

     They possess the desirable properties of ordinary soaps and can be used with hard water and in acidic solutions as well. Synthetic detergents are sodium salts of long chain benzene sulphonic acids or sodium salt of long chain alkyl hydrogen sulphates. Their calcium or magnesium salts are soluble in water.

Rocket Propellants

     Propellants are the fuels used in rockets for propulsion. For example, alcohol, liquid hydrogen, liquid ammonia, kerosene, hydrazine and paraffin can be used as propellants.

Insect Repellents

     The chemicals like dimethyl phthalate, N, N-diethyl - meta - toulamide (Deet), N - N - diethyl benzamide are used as effective repellents against mosquitoes, flies and other insects. These are widely used in insect repellant body creams.

Pheromones or Sex Attractants

     Another way to get rid of insects is to use pheromones or insect sex attractants. These chemicals help induce the mating urge and attract insects of opposite sex. When coated on poisonous baits, they prove fatal for insects. Methyl engenol attracts the oriental fruit fly. Bombykol attracts the silk worm moth.

Summary

     Our body is made up of tissues, which are all composed of chemicals. We need an adequate supply of chemicals in the form of food, vitamins, hormones, and enzymes, which are in turn chemicals. For taking care of our health we need medicines. We find that chemicals and chemistry penetrate intoevery aspect of our life. Paper, sugar, starch, vegetable oils, ghee, essential oils, tannery, distillery, soap, cosmetics, rubber, dyes, plastics, petroleum infact there is almost nothing that we use in our dailylife that is not a chemical. Continuing research will keep adding to this list.