Frontiers of chemistry

Organic chemistry is a young science. In the 19^th century chemists first synthesized, or put together, an organic compound from inorganic (non-organic) material. Further they showed that carbon atoms have four available bonds, which allow them to combine with other atoms.

Since those early years, the organic chemists invented many techniques for analyzing compounds whose structures are unknown and for preparing compounds that do not exist in nature. Many of these compounds are now used as medicines, dyes, foods and other products of industry.

In the last few decades’ chemists learned a great deal about the way in which the properties of a molecule are related to its structure. With the help of this knowledge they made great studies in understanding the structure of giant molecules.

Another striking development is the increased use of catalysts in both industrial and laboratory processes. Since no one yet knows precisely how catalysts work, each one has to be found by trial and error. Eventually we shall have such tailor-made catalysts, for we already know quite a lot about the action of the existing ones.

The most difficult problems in organic chemistry are those connected with investigating the compounds in living things. Although our knowledge is slight, it is growing rapidly.

Think for a moment of photosynthesis, the process by which water and carbon dioxide combine in a green plant to from sugar. Although every single person depends on photosynthesis for his food supply, we still do not understand the reaction. When photosynthesis can be carried out artificially on a large scale, we shall be able to set up factories to mass-produce food.

COMMENTERY

a great deal - багато

by trial and error - по методу спроб

tailor-made catalysts - готові каталізатори

quite a lot - дуже багато

to mass-produce food - для масового виробництва продуктів харчування

Polymers – atoms in strings

We know that natural products like wood, petroleum and coal play an important part in our modern civilization. In about 1880 organic chemists set out to discover how the molecules of these products are constructed. They realized that once they had this knowledge they would be able to make better and more versatile materials in the laboratory. Careful study over a period of many years has finally made known as important fact: the molecules of all natural organic materials that are strong, elastic, insoluble and melt at high temperature have one important feature in common – giant size.

But until 1920’s almost nothing was known about architecture of these giant molecules. Chemists found it very difficult to tell how they were put together by nature, and to see how they might be built up in the laboratory.

Gradually chemists realized that the giant molecules must be composed of large numbers of smaller units connected end-to-end. Like cars in a train, each molecule of cellulose must be made of strings of simple glucose molecules; each molecule of rubber must be made of strings of simple molecules (called isoprene molecules), and so on. These simple molecules are called monomers (from a Greek word meaning “single parts”). The large molecules are called polymers (meaning “many parts”).

It is one thing to use materials ready-made by nature. But it is quite another to design and built special materials in the laboratory. As the chemist discovered how the behavior of a polymer depends on its molecular structure, he realized that this knowledge would give him the possibility to design molecules that would behave just as he wanted them to. This is precisely what happened with nylon and synthetic rubber.

At our present state of knowledge, we know what molecular structure is needed to produce a particular property. We also have about 40 materials at our disposal, which can be used as monomers. Most of them are obtained from coal and petroleum. Using these materials, we have produced all the synthetics fibers, plastics and rubbers, each with the properties that the chemist intended them to have.

One familiar man-made polymer is the plastic called polyethylene. An important synthetic rubber, superior to natural rubber in many ways, called butyl rubber is widely used in automobile industry.

Fibers like nylon, rubbers like butyl rubber, and plastics like polyethylene are only a few of the interesting and useful polymers that chemists have created. Using their knowledge, scientists are now working to understand and to imitate the giant polymers in living organisms.

COMMENTARY

play an important part - відіграють важливу роль

have one feature in common - мають одну загальну особливість

and so on - і т. д.

Ready-made - готові

just as - саме так, як

superior to natural rubber in many ways - який багато в чому перевершує природний каучук