Describe the structural formulae and reactions of compounds containing selected functional groups 4 credits

Haloalkane Haloalkane Alcohol Alcohol Alkene Alkene Alkyne Alkyne Ester Ester Carboxylic acid Carboxylic acid Selected organic functional groups are limited to: Compounds are limited to: Those containing no more than 8 carbons. Larger organic molecules may be used in Qs linking structure & reactivity.

Acid reactions of carboxylic acid Distinguishing tests Structural and geometric isomers Knowledge of primary, secondary & tertiary alcohols & haloalkanes Naming compounds Cl 2 H 2 O/H + & HCl identify major & minor products Br 2 MnO 4 - Oxidation of primary alcohols to carboxylic acid polymerisation H 2 /Pt Halogenation of alkanes Elimination of water from alcohol Organic Chemistry Reactions of alkenes Formation & hydrolysis of esters e.g. triglycerides

Fats, oils and soaps Triglyceride is a fat that contains 3 ester linksTriglyceride is a fat that contains 3 ester links Made from 3, long-chain carboxylic acids + glycerol (triol)Made from 3, long-chain carboxylic acids + glycerol (triol) In the esterfication reaction, 3H 2 0 is formed (OH from acid + H from glycerol)In the esterfication reaction, 3H 2 0 is formed (OH from acid + H from glycerol)

Beware; they can change the orientation Divide between C and O, add Hs to form triol and OHs to form acid

Fats, oils and soaps Like all esters, triglycerides undergo hydrolysis. This reaction can be catalysed by either acid or base. 1.With acid An acid catalyst is used (not conc. acid) to form glycerol (triol) and carboxylic acid again: 2.With alkali (OH - ) If NaOH is used, it reacts with the carboxylic acid to form a sodium salt and glycerol. The sodium salt in this case is called ‘soap’ and the reaction is called ‘saponification’

Acid conditions: glycerol and palmitic acid formed. Alkali conditions: glycerol and the sodium salt of palmitic acid formed

Notice there are 3 diff. acids

In basic conditions: glycerol would still form but instead of the acid a sodium salt would form.

Na

Polymerisation A polymer is a large molecule made of small molecules called monomersA polymer is a large molecule made of small molecules called monomers In addition polymerisation, nothing else is madeIn addition polymerisation, nothing else is made All monomers are alkenesAll monomers are alkenes Could be asked to draw monomers from polymers or vice versaCould be asked to draw monomers from polymers or vice versa

OH CH=CH 2 Isolate 2 carbons to form the basis of the alkene monomer Break the double bond, attach to next monomer

Isolate 2 carbons, straighten them and put the double bond in

Naming compounds Learn functional groups and endings! GroupStructure Name ending AlkaneC-C-ane AlkeneC=C-ene AlkyneC=C-yne Alcohol-OH-anol Haloalkane e.g. –Cl e.g Chloro-ane Carboxylic acid OHC=O -anoic acid Ester-C=O O-thyl-anoate

1-chloropropane methylpropanoate Crocodiles! What is eaten first is named first! Numbering begins at ene end -anoic grp is always on carbon 1

Structural isomers Same number of atoms in a different arrangement Geometric isomers Different arrangements of atoms in space Different arrangements of atoms in space Cis (same side) & trans (across) Cis (same side) & trans (across) Due to double bond being unable to rotate Due to double bond being unable to rotate Can have different properties e.g. polarity & boiling point Can have different properties e.g. polarity & boiling point

methylpropenecyclobutane Don’t need to give number placing for methyl and ene. They can be nowhere else!

But-1-eneBut-2-ene Cannot form cis & trans because the groups on each C are not different Can form cis & trans because the groups on each C are different and the double bond doesn’t allow rotation Base the drawing around the double bond to examine the groups Remember this! It’s the stock answer for explaining geometric isomers

Reactions of alkenes Reaction type ReagentConditionsProduct HydrogenationHydrogen Pt/H 2 or Ni/H 2 Alkane HydrationWater H + /H 2 0 Alcohol HalogenationHalogen Br 2 or Cl 2 Haloalkane Halogenation Hydrogen halide HCl or HBr Haloalkane Oxidation Potassium permanganate H + /MnO 4 - Diol All types of addition reactions Watch out for Markovnikov’s! Asymmetrical alkene = 2 products

Primary, secondary & tertiary Classifications in alcohols and haloalkanes Classifications in alcohols and haloalkanes Look at the Carbon the alcohol/halogen is attached to. Is this attached to 1, 2 or 3 carbons? Look at the Carbon the alcohol/halogen is attached to. Is this attached to 1, 2 or 3 carbons? Form straight line (!), T-shape or cross Form straight line (!), T-shape or cross

primary secondary primary tertiary

Reactions of alcohols Elimination of water (dehydration): Elimination of water (dehydration): alcohol  Alkene + water Oxidation of 1° alcohol: Oxidation of 1° alcohol: 1° alcohol  (aldehyde)  Carboxylic acid Can use H + /MnO 4 - as oxidising agent instead. Purple to colourless Esterfication: Esterfication: alcohol + Carboxylic acid  ester Conc. H 2 SO 4 H + /Cr 2 O 7 2- Dichromate turns from orange to green Conc. H 2 SO 4

This is a dehydration reaction (elimination) Alcohol + acid…

Oxidation of a primary alcohol… Potassium permanganate will turn from purple to colourless

Reactions of carboxylic acids Normal acid reaction e.g. fizzing with metal  H 2 & fizzing with carbonates  CO 2 & litmus turning red Normal acid reaction e.g. fizzing with metal  H 2 & fizzing with carbonates  CO 2 & litmus turning red Form metal salts involving the organic acid e.g. sodium methanoate Form metal salts involving the organic acid e.g. sodium methanoate Form esters when reacted with alcohols Form esters when reacted with alcohols

Distinguishing tests Group Damp litmus H + /Cr 2 O 7 2- Sodium carbonate sol. Smell Warm H + /MnO 4 - Bromine water Alcohol 1° turns from orange to green Forms 1 layer 1° turns from purple to colourless Stays orange Haloalkane Forms 2 layer Stays purple Stays orange Carbox. Acid Turns red Stays orange Forms 1 layer that fizzes pungent Stays purple Stays orange Ester Forms 2 layers fruity Stays purple Stays orange Alkane Forms 2 layers Stays purple Slowly decolour w/ uV Alkene Stays orange Forms 2 layers strong Purple to colourless Quickly decolour

Acidified potassium dichromate (H + /Cr 2 O 7 2- ) Propan-1-ol will turn acidified potassium dichromate from orange to green. Propanoic acid will remain orange. There are other possible answers, see how many you can come up with!

hexanehex-1-ene Decolourises bromine slowly with UV light Decolourises bromine quickly Saturated so undergoes a substitution reaction unsaturated so undergoes an addition reaction Forms 1-bromohexane Forms 1,2-dibromohexane CH 3 CH 2 CH 2 CH 2 CH 2 CH 3 + Br 2  CH 2 BrCH 2 CH 2 CH 2 CH 2 CH 3 + HBr CH 2 CHCH 2 CH 2 CH 2 CH 3 + Br 2  CH 2 BrCBrCH 2 CH 2 CH 2 CH 3 + HBr

Adding water to an asymmetric alkene…but which product goes where? End product = ester. Reagent = alcohol. So C must be… Propanoic acid So B must be a primary alcohol and reagent D must be an oxidant Propan-1-ol H + /Cr 2 O 7 2- Propan-2-ol To form a sodium salt of an ester… NaOH