Organic Chemistry
Organic Chemistry Carbon • Forms stable C–C bonds allowing extended structures • most other elements cannot do this • Forms stable bonds with other elements • Ability to form single, double or triple bonds • Bonds can be flexible and rotate or inflexible and be rigid • Strong and weak bonds available • Manipulate biological structures 3D Structures: Carbon forms a sp3 hybridisation with a tetrahedral structure • The shape of a molecule and severely effected its physical and chemical properties • Bond angles • Bond length • Direction of functional groups
Hydrocarbons Types
Contain a benzene ring or a derivative of a benzene ring
Single
Double
Triple
Properties • non-polar • Insoluble in water • Soluble in other organic solvents • Low mp.p/b.p. • Molecular weight increases so too does m.p./b.p. • Less dense than water • Increase in density = decrease in solubility
Alkane
Alkene/Alkyne
Aromatic Rings
-
- React with hydrogen (across
- Unsaturated - Bond Angle = 180˚ - Linear geometry
-
CnH2n+1 Saturated Linear or branched Relatively unreactive however can combust Bond Angle = 109.5˚ Tetrahedral
-
the π-bond) when with a catalyst Unsaturated Bond Angle = 120˚ Triganol planar geometry
- Bond length = 1.20 x 10-10 m - Bond length = 1.54 x 10-10 m - Bond length = 1.34 x 10-10 m
Functional Group Is an atom or a group of atoms that is responsible for the chemical and physical properties of the molecule • Organic molecules are classified according to their functional group • Similar functional group compounds react similarly • Reactions occur at functional groups • properties of functional groups can predict the products of the reaction • Common functional groups will undergo the same reactions
Alkenes Polyethylene
- Polymerisation - Break the double bond to make a large chain of carbon to carbon bonds Geometric Isomerism • Double bond causes planarity and rigidity • 2 possible isomers possible
• E = opposite • Z = same side • Interconverting between E/Z • High temperature needed to rotate the bond and then the bond reforms Reactions Hydrogenation Addition of H2 to an alkene • Requires a catalyst - used to break the H2 bond to allow it to bond with the alkene • Palladium • Platinium • Nickel • Heat and pressure is sometimes also necessary • Z/cis isomerism always occurs 1. H2 is absorbed onto the catalyst’s surface — this causes the Z-isomer
2. C2R4 double bond clings to the catalyst’s surface 3. Hydrogen atom 1 by 1 transfers to create an alkane in the same plane • Product desorbs from the catalyst surface
Example: Fats and Oils • Fats: Long hydrocarbon chains with double bonds (fewer than oils) • Oils: Long hydrocarbon chains with double bonds • Hydrogenation of these oil double bonds can cause hardening - E.g. peanut oil hydrogenation of double bond = peanut butter Halogenation Addition of halogen molecules to an alkene — Cl2 or Br2 = di… product
Hydrohalogenation Addition of H – X to an alkene Types • Addition to symmetrical alkene - Gives 1 isomer product • Addition to unsymmetrical alkene - 2 isomer products possible - Regioselective reaction - 1 product is only ever observed (favoured)
Reactions Mechanisms Energy Diagram
Hydrocarbons Types
Contain a benzene ring or a derivative of a benzene ring
Single
Double
Triple
Properties • non-polar • Insoluble in water • Soluble in other organic solvents • Low mp.p/b.p. • Molecular weight increases so too does m.p./b.p. • Less dense than water • Increase in density = decrease in solubility
Alkane
Alkene/Alkyne
Aromatic Rings
-
- React with hydrogen (across
- Unsaturated - Bond Angle = 180˚ - Linear geometry
-
CnH2n+1 Saturated Linear or branched Relatively unreactive however can combust Bond Angle = 109.5˚ Tetrahedral
-
the π-bond) when with a catalyst Unsaturated Bond Angle = 120˚ Triganol planar geometry
- Bond length = 1.20 x 10-10 m - Bond length = 1.54 x 10-10 m - Bond length = 1.34 x 10-10 m
Functional Group Is an atom or a group of atoms that is responsible for the chemical and physical properties of the molecule • Organic molecules are classified according to their functional group • Similar functional group compounds react similarly • Reactions occur at functional groups • properties of functional groups can predict the products of the reaction • Common functional groups will undergo the same reactions
Alkenes Polyethylene
- Polymerisation - Break the double bond to make a large chain of carbon to carbon bonds Geometric Isomerism • Double bond causes planarity and rigidity • 2 possible isomers possible
• E = opposite • Z = same side • Interconverting between E/Z • High temperature needed to rotate the bond and then the bond reforms Reactions Hydrogenation Addition of H2 to an alkene • Requires a catalyst - used to break the H2 bond to allow it to bond with the alkene • Palladium • Platinium • Nickel • Heat and pressure is sometimes also necessary • Z/cis isomerism always occurs 1. H2 is absorbed onto the catalyst’s surface — this causes the Z-isomer
2. C2R4 double bond clings to the catalyst’s surface 3. Hydrogen atom 1 by 1 transfers to create an alkane in the same plane • Product desorbs from the catalyst surface
Example: Fats and Oils • Fats: Long hydrocarbon chains with double bonds (fewer than oils) • Oils: Long hydrocarbon chains with double bonds • Hydrogenation of these oil double bonds can cause hardening - E.g. peanut oil hydrogenation of double bond = peanut butter Halogenation Addition of halogen molecules to an alkene — Cl2 or Br2 = di… product
Hydrohalogenation Addition of H – X to an alkene Types • Addition to symmetrical alkene - Gives 1 isomer product • Addition to unsymmetrical alkene - 2 isomer products possible - Regioselective reaction - 1 product is only ever observed (favoured)
Reactions Mechanisms Energy Diagram
