Tudo se transforma, Reações Químicas, Fritz Haber e a síntese da amônia

Have you ever stopped to think what is needed to produce so much food? Currently, world population is estimated at over 6 billion and 500 million humans. How is it possible to feed so many?

And if all the world's food is not enough to feed the world? What to do? We need to produce millions of tons of food a day to ensure food for so many.

Can you imagine this process? Planting, care, harvest and distribute this food every day? One of the great challenges facing humanity is to create more effective solutions for food production on a large scale.

Over time, it was discovered that plants need certain elements to grow. They basically use oxygen, hydrogen and carbon, present in abundant quantities in the soil water and atmospheric air. Beyond these elements, the plants require a minimal amount of other elements such as potassium, nitrogen and phosphorus, which are also removed from the ground.

However, many soils with insufficient amounts of potassium, nitrogen or phosphorus, preventing or hindering the healthy growth of the plant. They become, then the "limiting factors". If the soil does not have a minimum amount of potassium, nitrogen or phosphorus, the plant simply does not grow.

On our planet, there is not enough land, naturally fertile, to plant food for all. In search of a solution, many scientists have studied possibilities to enrich the soil. It was necessary to expand the area's fertile land, increasing the availability of limiting elements.

These researchers found that the limiting elements should be in a bioavailable form. Ie in a form capable of being absorbed by plants, nitrogen, for example. Although there are a lot of nitrogen in the atmosphere, it is in the form of molecular nitrogen, which can not be effectively used by plants because its form is bioavailable nitrate.

Thus, we developed fertilizers, or fertilizers. Products that usually contains mostly potassium nitrate with calcium phosphate. But, the source of fertilizer?

The natural deposits of guano and saltpeter emerged as the first solution. The guano is the residue of feces of seabirds, deposited over thousands of years, forming a true islands off the coast of Peru. Since the salt mines are potassium nitrate, which is in northern Chile.

Such sources have been intensively explored in the second half of the nineteenth century. But would not last long. In the late nineteenth century, renowned scientists, such as Crookes, had indicated that these sources of fertilizers, non-renewable, they would run out.

At that time, England monopolized the trade of these products. For these reasons, the search for alternatives to fertilizers is replaced by a highly strategic value to other countries. One of them is Germany.

Newly unified Germany was very concerned with building their hegemony, both political and economic. Another interest of Germany in the survey was the fact that nitrates also enter the formulation of explosives. Noting that the rays producing the combination of nitrogen and oxygen from the atmosphere, we tried to do the same with the use of high electrical currents, industrially.

But it was a very expensive process. It is in this scenario that Fritz Haber. The man who carried out the synthesis of ammonia in order to produce it on an industrial scale, from molecular hydrogen and nitrogen, abundantly available.

This chemical reaction looks simple but is not. Transforming a nitrogen molecule and three hydrogen molecules into two molecules of ammonia is technically very complex because it requires high pressures and temperatures. Ostwald, Le Chatelier, Nerst, great scientists of the time, tried to accomplish the synthesis.

Everyone knew that the reaction needed high pressures and temperatures, and catalysts should be used. But that catalyst? How high should the pressure?

What would the reaction? Then comes Fritz Haber. He studied all this carefully.

Together with his team, built a container to withstand high pressure. New valves were developed. Several catalysts were investigated.

Finally, a strand of ammonia leaked from its reactor. Haber's work was successful in uniting science to technology. The scientific interests of the academy joined the commercial interests of the chemical industry that funded his work.

The use of the catalyst enabled the reaction occurred at very high temperatures and pressures, but possible to be used in industrial production. It was a team effort! The Haber process was taken on an industrial scale by Carl Bosch e.

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. Pronto! Now Germany could, from the ammonia, making its nitrate to fertilize their land and produce their explosives.

The fertilizers manufactured in this way provided an enormous breakthrough in large-scale agriculture. Today, billions of people can find something to eat, thanks to the work of Fritz Haber. Besides the great scientist, Haber was an extreme nationalist, and used his knowledge to produce chemical weapons.

Thousands of people died for it. Haber understand that as a scientist, it was his duty to use his knowledge to help his country win the war. Einstein, who was a close friend of Haber, disagreed with him and maintained a pacifist stance.

Germany loses the war and Haber is accused of war criminal and exiles. His experiments with chemical weapons and deadly gases reveal paradoxes between knowledge and ethics. Despite criticism from the scientific world, the studies that led to the Haber synthesis of ammonia and cost years of his life, gave him the glory and recognition.

When Haber returned to Germany, the Institute of Physical Chemistry in Berlin becomes the world's most advanced center in this field. His country, however, is very different. With the rise of Nazism in 1933, all public officials of Jewish origin are fired and are being persecuted.

Haber was a Jew. Haber died in exile in Switzerland in 1934, extremely bitter. His country, who are both dedicated Haber, ultimately denying him recognition as an equal.

Understand how chemical reactions take place, it is essential to be able to control them and get the results you desire. Much of the current work of scientists, known as chemicals, is dedicated to that understanding. The application of scientific knowledge is still unpredictable.

Today, the exaggerated use of fertilizers in agriculture and the very model of agriculture based fertilizers are causes for concern for the environmental impact they promote. Felling of forests, depletion and pollution of soil and freshwater. How to avoid these impacts?

How to maintain a sustainable food production on a large scale for a population that continues to grow? Find these answers came to be one of our greatest challenges. Science is alive and evolves to try to understand nature.

Nobody knows what the future will make what we know today. After all, everything changes, even the knowledge.