Organic Chemistry Reactions - Chapter 2

CHAPTER 2: REACTIONS OF ORGANIC COMPOUNDS MAIN TYPES OF REACTIONS in Organic Chem (not reactions to your last test!) I’m still learning I’m still learning the functional Whew! This She c...

CHAPTER 2: REACTIONS OF ORGANIC COMPOUNDS MAIN TYPES OF REACTIONS in Organic Chem (not reactions to your last test!) I’m still learning I’m still learning the functional Whew! This She called it to draw … class is easy! groups a Blood Bath!  1) Addition 2) Substitution 3) Elimination 4) Oxidation 5) Reduction 6) Condensation Types of Substitution Reactions 7) Hydrolysis  1) ADDITION REACTION Atoms added to a double or triple bond Alkene or Alkyne undergoes addition reaction to break a double or triple bond Example: catalyst Reactant XY added to alkene makes alkane To recognize: Two reactants make 1 product  1) ADDITION REACTIONS Common atoms that can be added to an alkene or alkyne H and OH (from H2O ) H and X (from H-X) where X= Cl , Br, or I X and X from (X2) where X= Cl , Br, or I H and H (from H2) Addition Reactions Flowchart  1) ADDITION REACTION Reactant Name of Process Product (Alkene +) Hydrogenation Alkane Hydrogen Pt, 500 ◦C (Alkyne +) Hydrogenation Alkene (limited Hydrogen amounts of Pt, 500 ◦C hydrogen) Or Alkane (excess of hydrogen) Water Hydration Alcohol (H2O, H2SO4) HF, HCl, HI, HBr Hydrohalogenation Halogenatated alkane Halogen Halogenation Double (UV light) Halogenated alkane  EXAMPLES: Addition Reactions 1) Room T 2) UV light  ADDITION REACTIONS: ALKENES Symmetrical molecule reacts with asymmetrical molecule to give one product. H2O, H2SO4 Symmetrical Asymmetrical  RULES FOR ADDITION Two asymmetrical molecules react to give two products. Example: + or Asymmetrical Asymmetrical Which product is favoured ?  “MARKOVNIKOV’S” Rule "the rich get richer" The carbon atom with the largest number of carbon atoms gets the X (halogen) or OH bind to it Therefore 2- bromobutane is favoured 2-bromobutane + Major product 1-bromobutane Minor Product  ADDITION REACTIONS: ALKYNES Also follow Markovnikov’s rule when asymmetrical UV light 1,1,2,2-tetrabromopropane Asymmetrical  ADDITION REACTIONS: ALKYNES May occur as two addition reactions: STEP #1: + STEP #2: +  2) SUBSTITUTION REACTION A hydrogen atom or functional group is replaced by a different functional group To recognize: two compounds react to form two products. 2-bromobutane 2-butanamine Alkyl halide + ammonia → amine + HX  2) SUBSTITUTION REACTION 1) CH3CH2-OH + HI CH3CH2-I + H2O ethanol iodoethane 2) 3) + KI  SUBSTITUTION REACTION Aromatics Aromatics can only undergo substitution reactions FeBr3  SUBSTITUTION REACTION Alcohols Halogens in HCl, HBr or HI can substitute the OH group of alcohol or the reverse. For Ex: CH3-CH2-OH + HCl CH3-CH2Cl + H2O The reverse reaction: CH3-CH2Cl + OH- CH3-CH2-OH + Cl- (from water)  3) ELIMINATION REACTION atoms are removed form a molecule to form double bonds. Reverse of addition To recognize: One reactant breaks into two products  ELIMINATION REACTION: Alcohol undergo elimination when heated in presence of strong acids, for example: H2SO4 Example: H2SO4  ELIMINATION REACTION: Alkyl Halides Undergo elimination to produce alkenes Bromoethane ethene hydrobromic acid  Reactions Part 2 Continuation Continuing from the previous lesson, the following reactions will be looked at in detail today: Condensation Reactions Hydrolysis Reactions Oxidation Reactions Reduction Reactions  4) CONDENSATION A) Esterification two molecules combine to form a single, bigger molecule. Water is usually produced in this reaction A carboxylic acid and alcohol can condense to form an ester – called “ esterification” A carboxylic acid and amine can condense to form an amide B) Amide Formation A carboxylic acid and amine can condense to form and amide, recall I showed you this when we learned about amides.  5) HYDROLYSIS water adds to a bond splitting it into two Reverse of a condensation reaction Water can add to an ester or amide bond Ester + water makes a carboxylic acid and alcohol Amide + water makes a carboxylic acid and amine 1-propanol  Reactions of Amides (hydrolysis) Example: Amide + water → Carboxylic acid + amine O O II H+, ∆ II CH3CH2C-NH-CH3 + H2O → CH3CH2C-OH + H2N-CH3  6) OXIDATION & 7) REDUCTION REACTIONS Change in the number of H or O atoms bonded to C Always occur together One reactant is oxidized while the other is reduced For now, lets focus on reactant only…  6) OXIDATION Carbon atom forces more bonds to Oxygen or less to Hydrogen For example: formation of C=O bond Occurs in presence of oxidizing agents [O] such as KMnO4, K2Cr2O7, and O3 For now, focus on organic reactant only  6) OXIDATION: Alcohol Alcohol oxidation can form an aldehyde or ketone Primary Alcohol Secondary Alcohol Tertiary Alcohols do not oxidize  6) OXIDATION: Aldehyde Aldehydes undergo oxidation to produce carboxylic acid Example:  7) REDUCTION REACTION Carbon atom forms fewer bonds to Oxygen or more bonds to Hydrogen Aldehydes, ketones and carboxyliic acids can be “reduced” to alcohols Alkenes and alkynes can be reduced to become alkanes Occurs in the presence of reducing agents such as LiAlH4, and H2 where Hydrogen [H] is added 7) REDUCTION: Alkene 7) REDUCTION: Aldehyde/Ketone 8) Combustion Reactions (Grade 11) Note: Not Balanced C.E. ∆ (Unlimited) ∆ (Limited)  Homework  Read Section 2.1 - Pages 96-112 Complete the following: Page 99 # 1-10 (addition rxn) Page 102 # 12-22 (elimination rxn) Page 104 # 23-32 (substitution rxn) Page 108 # 33-42 (condensation/hydrolysis) Page 113 # 43-52 (oxidation and reduction)