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www.soran.edu.iq ORGANIC AND BIOCHEMISTRY. Assistance Lecturer Amjad Ahmed Jumaa Organic chemistry Concept of organic chemistry. Classes of hydrocarbons. Follow problems. 1

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www.soran.edu.iq Organic chemistry Organic chemistry is the chemistry of the compounds of carbon. Chemical compounds Inorganic and Organic. 1-Inorganic compounds minerals, 2-Organic compounds vegetable or animal sources. Indeed, until about 1850 many chemists believed that organic compounds must have their origin in living organisms, and consequently could never be synthesized from inorganic material.

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4 The science of organic chemistry began to flower with the demise of a nineteenth century theory called vitalism. According to vitalism, organic compounds were only those that came from living organisms, and only living things could synthesize organic compounds through intervention of a vital force. Inorganic compounds were considered those compounds that came from nonliving sources.

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www.soran.edu.iq 5 Between 1858 and 1861, August Kekul, Archibald Scott Couper, and Alexander M. Butlerov, working independently, laid the basis for one of the most important theories in chemistry: the structural theory. Two central premises are fundamental: 1. The atoms in organic compounds can form a fixed number of bonds using their outermost shell (valence) electrons. Carbon is tetravalent ; that is, carbon atoms have four valence electrons and can form four bonds. Oxygen is divalent, and hydrogen and (usually) the halogens are monovalent :

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www.soran.edu.iq 6 2. A carbon atom can use one or more of its valence electrons to form bonds to other carbon atoms:

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www.soran.edu.iq 7 In 1874, the structural formulas originated by Kekul, Couper, and Butlerov were expanded into three dimensions by the independent work of J. H. vant Hoff and J. A. Le Bel. vant Hoff and Le Bel proposed that the four bonds of the carbon atom in methane, for example, are arranged in such a way that they would point toward the corners of a regular tetrahe-dron, the carbon atom being placed at its center The necessity for knowing the arrangement of the atoms in space, taken together with an understanding of the order in which they are connected, is central to an understanding of organic chemistry, and we shall have much more to say about this later.

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Classes of hydrocarbons Organic compounds contain only two elements, hydrogen and carbon, and hence are known as hydrocarbons. Structure hydrocarbons main classes, aliphatic and aromatic. Aliphatic hydrocarbons alkanes, alkenes, alkynes, and their cyclic analogs (cycloalkanes, etc.). Classes of hydrocarbons Organic compounds contain only two elements, hydrogen and carbon, and hence are known as hydrocarbons. Structure hydrocarbons main classes, aliphatic and aromatic. Aliphatic hydrocarbons alkanes, alkenes, alkynes, and their cyclic analogs (cycloalkanes, etc.).

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www.soran.edu.iq 10 The simplest member of the alkane family, indeed, one of the simplest of all organic compounds is methane, CH 4.

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www.soran.edu.iq 11 follow problem: Determine which of the following compounds are aliphatic and aromatic, and determine their families: A) C 6 H 6 B) NO 2 C 6 H 5 C) CH 3 CH 2 CH 2 CH 3 D) CH 2 =CHCH 3 E) CHClCH 2 CH 2 CH 3 F)