SL Reaction pathways Deduce reaction pathway given the starting materials and the product, e.g: CH3CH2OH CH3CH2CHO Conversions with more than two stages will not be assessed. Reagents, conditions and equations should be included The compound and reaction types in this topic are summarized in the schemes on the next slides K2Cr2O7

propane propanoic acid polypropene propanal 1-propanol propene oxidation polypropene propanal oxidation (M) polyaddition +H2O 1-propanol addition propene (M) substitution +OH- addition +HCl addition 1-chloro-propane +H2 (M) substitution via radical reaction 1,2-dichloro-propane (M) substitution via radical reaction propane (M) further radical substitution to tri- and tetra-chloropropane

propane propanoic acid propanal polypropene 1-propanol propene Oxidation of primary alcohol with acidified K2Cr2O7. Reflux to get the product propanal polypropene Oxidation of primary alcohol with acidified K2Cr2O7. Distillation to get the product Poly-addition. Radical mechanism. Initiation, prolongation and termination 1-propanol Addition reaction. Hydrogen halide (HCl), spontaneous at STP (M) substitution reaction with NaOH; SN1 or SN2 propene 1-chloro-propane Addition reaction. H2 and Ni-catalyst (M) substitution via radical mechanism. Induced by homolytic cleavage of Cl2 by UV-light (M) substitution via radical mechanism. Induced by homolytic cleavage of Cl2 by UV-light 1,2-dichloro-propane propane (M) further radical substitution to tri- and tetra-chloropropane

carboxylic acid polyalkene aldehyde primary alcohol alkene oxidation aldehyde (M) polyaddition oxidation alkene primary alcohol (M) substitution +OH- addition addition +HCl +Cl2 chloroalkane (M) substitution via radical reaction (M) substitution via radical reaction dichloroalkane alkane (M) further radical substitution to tri- and tetra-chloropropane

butane 1-chloro-butane What is formed? oxidation oxidation (M) polyaddition addition +HCl (M) substitution +OH- addition 1-chloro-butane +H2 (M) substitution via radical reaction (M) substitution via radical reaction butane (M) further radical substitution to tri- and tetra-chloropropane

propane propanone polypropene 2-propanol 1-propene 2-chloro-propane oxidation (M) polyaddition 2-propanol 1-propene addition +HCl (M) substitution +OH- addition +H2 2-chloro-propane 1,2-dichloro-propane (M) substitution via radical reaction (M) substitution via radical reaction propane (M) further radical substitution to tri- and tetra- chloropropane

propane propanone polypropene 2-propanol 1-propene 2-chloro-propane Oxidation of secondary alcohol with acidified K2Cr2O7 polypropene 2-propanol (M) polyaddition (M) substitution +OH- addition 1-propene 2-chloro-propane +HCl addition (M) substitution via radical reaction +Cl2 (M) substitution via radical reaction 1,2-dichloro-propane propane (M) further radical substitution to tri- and tetra chloropropane

polyalkene ketone secondary alcohol alkene secondary chloroalkane oxidation (M) polyaddition secondary alcohol addition (M) substitution +OH- +HCl alkene addition secondary chloroalkane +H2 (M) substitution via radical reaction (M) substitution via radical reaction alkane dichloroalkane (M) further radical substitution to tri- and tetra chloropropane

butane 2-chloro-butane What is formed? oxidation substitution +OH- 2-chloro-butane substitution via radical reaction butane

Draw structural formula of reactants and products, name them and give reaction pathway K2Cr2O7 CH3CH2CHO H2 CH3CH=CHCH3 NaOH K2Cr2O7 CH3Br UV-light, Cl2 CH3CH3 HI CH3CH=CHCH2CH3

Answers K2Cr2O7 CH3CH2CHO CH3CH2COOH oxidation propanal propanoic acid CH3CH=CHCH3 CH3CH2CH2CH3 addition 2-butene butane NaOH K2Cr2O7 CH3Br CH3OH CH2O substitution oxidation methylbromide methanol methanal UV-light, Cl2 CH3CH3 CH2ClCH3 radical substitution ethane chloroethane HI CH3CH=CHCH2CH3 CH3CHICH2CH2CH3 addition 2-pentene 2-iodopentane

1-3. Substitution via radical mechanism 1-3. Substitution via radical mechanism. Induced by homolytic cleavage of Cl2 by UV-light.   4. Addition reaction. Hydrogen halide, spontaneous at STP 5. Addition reaction. H2 and Ni-catalyst 6. Addition reaction. Halogene, spontaneous at STP 7. Poly-addition. Radical mechanism. Initiation, prolongation and termination 8. Substitution reaction with NaOH; SN1 or SN2 9. Oxidation of primary alcohol with acidified K2Cr2O7. Distillation to get the product 10. Oxidation of primary alcohol with acidified K2Cr2O7. Reflux to get the product 11. Oxidation of secondary alcohol with acidified K2Cr2O7

HL Reaction pathways propene 1-chloro-propane butanenitrile 1-propanol (M) Substitution reaction. SN1 or SN2 CN- propene 1-chloro-propane butanenitrile (M) Elimination reaction. Hot, concentrated and reflux Reduction with H2 and Ni-catalyst (M) Substitution reaction. SN1 or SN2 NH3 1-propanol propylamine, butylamine Condensation reaction. Acid catalyst (or alkaline catalyst, but more common when hydrolysis of ester). Equilibrium reaction. Condensation reaction. Acid catalyst (or alkaline catalyst). Equilibrium reaction. propanoic acid 1-propyl propanoate propyl amide

HL Reaction pathways nitrile alkene chloropropane alcohol amine (M) Substitution CN- (M) Elimination chloropropane Reduction (M) Substitution alcohol amine Condensation carboxylic acid Condensation ester amide

1-chloro-butane 1-butanol butanoic acid What is formed? substitution CN- 1-chloro-butane elimination reduction H2 substitution NH3 1-butanol Condensation reaction. Acid catalyst (or alkaline catalyst, but more common when hydrolysis of ester). Equilibrium reaction. Condensation reaction. Acid catalyst (or alkaline catalyst). Equilibrium reaction. butanoic acid

HL Reaction pathways alkene 1. Elimination reaction. Hot, concentrated and reflux 2. Substitution reaction. SN1 or SN2 3. Substitution reaction. SN1 or SN2. (Can be substituted up 4 times to a quarternary ammonum salt) 4. Condensation reaction. Acid catalyst (or alkaline catalyst, but more common when hydrolysis of ester). Equilibrium reaction. 5. Condensation reaction. Acid catalyst (or alkaline catalyst). Equilibrium reaction. 6. Nitrile to amin: Reduction with H2 and Ni-catalyst 6