C G Ramachandran Nair
Two years ago, the world celebrated the International Year of Chemistry (IYC 2011). It was an African country, Ethiopia, which submitted a proposal to observe 2011 as the International Year of Chemistry. This was co-sponsored by 23 member countries of the United Nations and was supported by all the member countries. The IYC programmes involved chemical societies, academies, and similar institutions worldwide.
Why 2011? Well, 2011 was the centenary year of the Nobel Prize in chemistry (1911) given to Madame Marie Curie (1867-1934), who toiled in the laboratory for years under difficult circumstances and finally succeeded in isolating radium from the ore “pitchblende”. Incidentally, 2011 also marked the bicentennial year of the famous Avogadro Law!
The official theme of IYC 2011 was: “Chemistry-Our Life-Our Future”. This theme underlines the importance of chemistry in the everyday life of man.
Chemistry, by definition, is the science of matter. Matter and energy constitute the stuff of the entire universe. Chemistry deals with matter and physics deals with energy. But, Einstein showed that matter and energy are interconvertible.
Chemistry touches everything “from salt to camphor” (“uppu thottu karpooram ware”, as expressed elegantly in Malayalam!). All the substances in the material world are chemicals. The air we breathe is a mixture of nitrogen and oxygen. The water we drink is a compound of hydrogen and oxygen (“dihydrogen monoxide”). The food we eat is mostly carbohydrates, proteins, and fats, all of which are chemical compounds of varying complexities. The clothes we wear are made of chemical polymers. Some are natural polymers (like cotton, wool, and silk); some are synthetic polymers (like nylon, polyester, and acrylic). The medicaments we use are all chemicals (e.g., aspirin, paracetamol, penicillin, etc). Essential micronutrients like vitamins are all chemical compounds. Why, our bodies are also composed of matter only!
A central science
Chemistry is a central science. It is related to physics and mathematics. Thus, we have physical chemistry, chemical physics, computational chemistry and the like. Chemistry is also closely connected with life sciences. Consider organic chemistry, biochemistry, medicinal chemistry, food chemistry, etc. In a third direction, chemistry interacts with earth sciences and atmospheric sciences. Geochemistry, mineral chemistry, atmospheric and stratospheric chemistry are examples of such interactions. We further have astrochemistry (chemistry of stars), nuclear chemistry, and so on. Amongst these multifarious disciplines, the science of chemistry stands at the centre, connecting these peripheral disciplines.
Chemistry is also a giant science with innumerable branches. We have the main branches – inorganic, physical, organic, and analytical chemistry. Then we have specialities like solid-state chemistry, thermochemistry, electrochemistry, magnetochemistry, chemistry of natural products, photochemistry, petroleum chemistry, quantum chemistry, crystal chemistry, surface chemistry, etc. We have superspecialities like photoelectrochemistry, defect solid chemistry, semiconductor chemistry, superconductor chemistry, etc. Indeed we can compare chemistry to a giant banyan tree spreading its branches all around.
Chemists study all natural products and try to synthesize them by different routes usually unknown to nature. The list of naturally occurring products successfully synthesized by man is long – drugs like quinine, alkaloids like morphine and brucine, vitamins like ascorbic acid (Vitamin C), dyes like indigo, etc. In most of these cases, the synthetic substance is cheaper than the natural product. Synthesis has been achieved for other substances too, like insulin, sucrose (cane sugar), etc.; but these synthetic products are at present more expensive than the natural products.
Chemistry surpasses nature. Chemistry has given us many new substances, unknown to nature. Once again, the list is long – synthetic dyes, drugs, fertilizers, alloys, composites, plastics, polymers, ceramics, cement, detergents, cosmetics, and so on.
Take the case of plastics. They were unknown 50 years ago! Today we have innumerable things made from plastic-bags, briefcases, chairs, tables, doors and windows, wallets and purses, footwear, spectacle frames, water pipes and tubes, scientific instrument bodies, milk sachets, heart valves, blood bags, and so on.
Plastics are polymers; but all polymers are not plastics! For example, the natural fibres – cotton, wool and silk are not plastic. Also, while there are many natural polymers, there are few natural plastics. Synthetic polymers may however be plastics too. One of the first and most well known synthetic polymers is nylon, discovered in 1911 by Caruthers. Others like various polyesters and acrylics were soon made and these play a major role in the garment industry and play their part in clothing humanity. It may be noted that excessive use, abuse and mis-use of plastics has led to environmental problems too. Environmental chemistry and the emerging “green chemistry” are expected to solve these problems.
Fertilizers and pesticides
The Haber synthesis of ammonia and the subsequent production and widespread use of ammonium sulfate fertilizer was enthusiastically welcomed as a boon for starving humanity. The fertilizer chemist was hailed as a great benefactor of mankind and as “one who made two blades of grass grow where only one grew before”!
However, the use of fertilizers, pesticides, fungicides, etc., must be critically regulated. Wisdom and discretion must prevail here. Organic manure and biologic pesticides must be preferred wherever possible. The use of inorganic fertilizers and synthetic pesticides may be phased out when organic or biological substitutes are available.
Chemistry plays a major role in medicine. Acharya P C Ray had pointed out that in ancient India, “chemistry was the handmaid of medicine”. This continues to be so even today. Can we now imagine a world without antibiotics, sulpha drugs, vitamins and so on? All these are gifts of chemistry to medicine.
Chemistry has given us great boons. It has also given us tools of destruction. It is up to us to put this great science to good use only. One may here remember the great chemist Louis Pasteur who used chemistry only for good applications. Pasteur, as you know, invented the anti-rabies vaccine, special fermentation techniques, pasteurization, etc.
Chemical researchers in many countries are now trying to use hydrogen as the universal fuel. Hydrogen is abundantly available (from water!). Burning hydrogen produces only water vapour and so hydrogen qualifies as a non-polluting fuel. It is hoped that by 2050, all automobiles will run on hydrogen fuel.
Solar energy is also a high priority item for chemists, physicists, and engineers. Problems like concentration of solar energy and invention of more efficient catalytic converters in photovoltaic technology are two major problems here. Chemistry has a major role in developing more efficient materials for making better photovoltaic converters. We expect solar energy to meet most needs of man by the close of this century.
The chemical laboratory is a fascinating place. What colours, smells, and sounds we experience here! In one corner, we see the dazzling brilliance of a magnesium ribbon burning in oxygen. Elsewhere, we see the effulgence of phosphorus burning in oxygen in a round flask mimicking the brilliance of a miniature sun (“The chemical sun”, as one calls it). The mouth watering aromas of bananas and pineapples (due to esters like amyl acetate and ethyl isobutyrte), the chemical volcano (burning ammonium dichromate), etc., are the chemistry student’s initiation into college chemistry experiments. There are also bad smells galore, like that of hydrogen sulfide (smell of rotten eggs) and mercaptans (indescribably offensive and repugnant smell!). There are dangers too. Unexpected explosions may occur, like the one, which killed Alfred Nobel’s brother, or the one that destroyed one eye and one hand of Dulong.
But chemists love all these. Let me end this article by quoting the 17th century German chemist Johann Joachim Becher, who wrote in his book, Physica subterrana:
“Chemists are a strange class of mortals, impelled by an almost maniacal impulse to seek their pleasures amongst smoke and vapour, soot and flames, poisons and poverty, yet amongst all these evils I seem to live so sweetly that I would rather die than change places with the King of Persia.” –Johann Joachim Becher, Physica subterranea (1667)
The author was formerly Secretary, Science, Technology and Environment Council, Government of Kerala and Dean, Faculty of Science, University of Kerala. He can be reached at [email protected].