Hydrogenation

The hydrogenation reaction is a useful tool for a scientist trying to determine the structure of a new molecule. The molecular formula, showing the exact number of each kind of atom, can be determined in several ways, but discovering the arrangement of these atoms requires a large amount of detective work.

Sometimes, for example, a new substance is isolated from a plant, and a chemist needs to determine what the structure of this substance is. One method of attack is to find out how many molecules of hydrogen gas will react with one molecule of the unknown substance. If the ratio is, for example, two molecules of hydrogen to one of the unknown, the scientist can deduce that there are two carbon-carbon double bonds, or else one carbon-carbon triple bond in each molecule. Other kinds of chemical clues lead to the rest of the structure, and help the scientist to decide where in the unknown molecule the multiple bonds are.

One of the simplest uses of hydrogenation in the research laboratory is to make new compounds. Almost any organic molecule that contains multiple bonds can undergo hydrogenation, and this sometimes leads to compounds that were unknown before. In this way scientists have synthesized and examined many molecules not found in nature, or not found in sufficient quantity. These newly synthesized molecules are of use to humanity in a variety of ways.