lecture 4 basic concepts of organic chemistry.pptx

Bsn students

1. Lecture#4 basic concepts of organic chemistry Dr. K ehekshan Shahzadi

2. Organic chemistry is the study of the structure, properties, composition, reactions, and preparation of carbon-containing compounds. Most organic compounds contain carbon and hydrogen, but they may also include any number of other elements (e.g., nitrogen, oxygen, halogens, phosphorus, silicon, sulfur). Organic chemistry

3. The compounds in solid, liquid or gaseous states which contain carbon in their molecule are known as organic compounds. There are a large number of organic compounds and therefore a proper systematic classification was required. Organic compounds can be broadly classified as acyclic (open chain) cyclic (closed chain ). Organic Compounds

4. It was assumed that organic compounds are produced by living organisms due to the presence of Vital Force. This theory remained unchallenged and no one ever even made effort test this in lab. In 1828 , Germen Chemist Friedrich Wohler derived first organic compound from inorganic compound in lab. He basically reacted Ammonium cyanate and obtained urea. Urea obtained in this way was identical in all respects to the urea obtained from urine .

5. Organic Compounds Classification Moving on to their classification in detail:

6. These compounds are also known as aliphatic compounds, they have branched or straight chains. Following are the examples in this category. Acyclic or Open Chain Compounds:

7. These are cyclic compounds which contain carbon atoms connected to each other in a ring ( homocyclic ). When atoms other than carbon are also present then it is called heterocyclic. Examples of this type are as follows : Alicyclic or Closed Chain or Ring Compounds :

8. They are a special type of compound which contains  benzene and other ring related compounds. Similar to alicyclic, they can also have heteroatoms in the ring. Such compounds are called heterocyclic aromatic Benzenoid aromatic compound Some examples are as follows : Aromatic Compounds

9. (b) Non- benzenoid aromatic compounds

10. Low melting points Low boiling points Low solubility in water High solubility in nonpolar solvents Flammable Solutions are nonconductors of electricity Exhibit covalent bonding Exhibit isomersim Chemical reactions are slow Properties of organic compounds

11. Hydrocarbons   All organic compounds that are entirely made up of only two kinds of atoms, carbon and hydrogen. Typically , hydrocarbons are colorless gases that have very weak odors. Hydrocarbons can feature simple or relatively complex structures and can be generally classified into four subcategories, namely alkanes, alkenes, alkynes, and aromatic hydrocarbons.  Hydrocarbons

12. The study of hydrocarbons can provide insight into the chemical properties of other functional groups and their preparation. Furthermore , hydrocarbons such as propane and butane are used for commercial fuel purposes in the form of Liquefied Petroleum Gas (LPG). Benzene , one of the simplest aromatic hydrocarbons, serves as the raw material for the synthesis of many synthetic drugs

13. Saturated Hydrocarbons : In these compounds, carbon-carbon atoms and carbon-hydrogen atoms are held together by single bonds. These single-bonded compounds are the simplest hydrocarbons. These types of hydrocarbons don’t have double or triple bonds. In terms of hybridization, they have Sp 3   hybridised carbon atoms with no Sp 2  or Sp hybridised carbon atoms. They are together called alkanes which have a general formula of C n H 2n+2 . For example, CH 4 andC 3 H 6 . Types of Hydrocarbons

14. Unsaturated Hydrocarbons : These compounds consist of a single, double or triple bond between carbon-carbon atoms. The double-bonded compounds are called alkenes, and the triple-bonded compounds are called alkynes. The general formula for alkenes is C n H 2n,  and for alkynes, the general formula is C n H 2n-2 . Cycloalkanes : These hydrocarbons possess one or multiple carbon rings. The hydrogen atom is attached to the carbon ring. .

15. Aromatic Hydrocarbons: They are also called arenes. Arenes are compounds which consist of at least one aromatic ring. Aliphatic Hydrocarbons: They are straight chain structures having no rings in them. Alicyclic Hydrocarbons :  They are hydrocarbons having a ring structure in them. The carbons atoms can be Sp , Sp 2 , or Sp 3   hybridised

16. The term molecule refers to very large molecules and something that consists of more than one atom. Herman Staudinger coined it in 1920. Macromolecules are so huge that these are made up of more than 10,000 or more atoms. Macromolecules  

17. Macromolecules are also termed as polymers. They are formed by the polymerization of molecules such as carbon, hydrogen and oxygen. The monomer units of macromolecules are polar in nature, with their heads and tails with different physical and chemical properties .

18. There are three main types of biological macromolecules, according to mammalian systems: Carbohydrates Nucleic acids Proteins Lipids Types of Macromolecules

19. Carbohydrates Carbohydrates are polymers of carbon, hydrogen and oxygen. They can be classified as monosaccharides, disaccharides and polysaccharides. Carbohydrates are found in starch, fruits, vegetables, milk and sugars. They are an important source of a healthy diet.

20. Nucleic Acids The nucleic acids include DNA and RNA that are the polymers of nucleotides. Nucleotides comprise a pentose group, a phosphate group, and a nitrogenous base group. All the hereditary information is stored in the DNA. The DNA synthesized into RNA and proteins.

21. Proteins Proteins are the polymers of amino acids. These include the carboxylic and the amino group. There would be no lipids or carbohydrates without proteins because the enzymes used for their synthesis are proteins themselves.

22. Lipids Lipids are a hydrophobic set of macromolecules, i.e., they do not dissolve in water. These involve triglycerides, carotenoids, phospholipids, and steroids. They help in the formation of the cell membrane, formation of hormones and in the and as stored fuel.