UNIVERSITY OF THE GAMBIA
COURSE: PRINCIPLES OF CHEMISTRY II (ORGANIC CHEMISTRY)
LECTURER: ANTHONY F. ADJIVON
Organic chemistry started as the chemistry of life, when that was thought to be different from the chemistry in the laboratory. Then it became the chemistry of carbon compounds, especially those found in coal. Now it is both. It is the chemistry of the compounds of carbon along with other elements such hydrogen as are found in living things and elsewhere. The organic compounds available to us today are those present in living things and those formed over millions of years from dead things. In earlier times, the organic compounds known from nature were those in the ‘essential oils’ that could be distilled from plants and the alkaloids that could be extracted from crushed plants with acid. Menthol is a famous example of a flavouring compound from the essential oil of spearmint and cis-jasmone an example of a perfume distilled from jasmine flowers. Organic chemistry is the study of carbon compounds. It is also said that an organic compound is any member of a large class of chemical compounds whose molecules contain carbon and hydrogen but carbides, carbonates, carbon oxides and elementary carbon are not organic compounds. Carbon compounds make up the structure of all living things. Organic chemistry is the study of carbon compounds. Nearly all compounds found in living organisms and make up the structure of all living things are still classified as organic compounds as are many compounds that have been synthesized in the laboratory that have never been found in living organisms. Over 7 million organic compounds are known and the number is constantly growing whereas there are only about 1.5 million known inorganic compounds i.e. the compounds of the remaining 114 elements. This makes it very important to study the chemistry of this wide range of compounds. For the first time, an “organic” compound had been obtained from something other than a living organism and certainly without the aid of any kind of vital force. Clearly, chemists needed a new definition for “organic compounds.” Organic compounds are now defined as compounds that contain carbon. Why is an entire branch of chemistry devoted to the study of carbon-containing compounds? We study organic chemistry because just about all of the molecules that make life possible—proteins, enzymes, vitamins, lipids, carbohydrates, and nucleic acids—contain carbon, so the chemical reactions that take place in living systems, including our own bodies, are organic reactions. Most of the compounds found in nature—those we rely on for food, medicine, clothing (cotton, wool, silk), and energy (natural gas, petroleum)—are organic as well. Important organic compounds are not, however, limited to the ones we find in nature. Chemists have learned to synthesize millions of organic compounds never found in nature, including synthetic fabrics, plastics, synthetic rubber, medicines, and even things like photographic film and Super glue. Many of these synthetic compounds prevent shortages of naturally occurring products. For example, it has been estimated that if synthetic materials were not available for clothing, most of the arable land would have to be used for the production of cotton and wool just to provide enough material to clothe us. Currently, there are about 16 million known organic compounds, and many more are possible. What makes carbon so special? Why are there so many carbon-containing compounds? The answer lies in carbon’s position in the periodic table. Carbon is in the center of the second row of elements. The atoms to the left of carbon have a tendency to give up electrons, whereas the atoms to the right have a tendency to accept electrons. The course will cover the following topics and special emphasis will be placed on examples related to medicine and biology. 1. The...
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