AS/A2 Chemistry Organic Reactions

Alkane ---> Haloalkane = Free radical substitution

1. Inititation: Cl2 --> 2Cl.

2. Propogation: Cl. + CH4 --> HCl + CH3.

                         CH3. + Cl2 --> CH3Cl + Cl.

3. Termination: Cl. + Cl. --> CL2

                        CH3. + Cl --> CH3Cl

                        CH3. + CH3. --> C2H6

Conditions = UV light for initiation

N.B. Cl. = Chlorine free radical

Haloalkane ---> 1y Alcohol = Nucleophilic Substitution

Lone pair on nucleophile moves to C+ and C-X bond moves onto X-

X- (halide ion) breaks off and nucleophile takes its place

Condtions = NaOH/KOH(aq) in ethanol solvent at room temperature

Haloalkane ---> Nitrile = Nucleophilic Substitution

Same mechanism as above

Conditions = KCN(aq) in ethanol solvent with heat

Haloalkane ---> 1y Amine = Nucleophilic Substitution

Same mechanism (N-H bond moves to N+, H+ breaks off and it joins to 2nd NH3)

Conditions = Excess conc. NH3(aq) in ethanol solvent with heat

Haloalkane ---> Alkene = Elimination

Lone pair on base goes to H

C-H bond goes to C-C bond (between 1st C and a neighbouring C)

H2O formed

C-X bond moves onto X-

X- breaks off

Conditions = NaOH/KOH wth heat and dissolved in ethanol (no water present)

Alkene ---> Haloalkane = Electrophilic Addition

Double bond moves out to H and H-X bond moves to X-

Lone pair of X- moves to C+ of carbocation

Conditions = HX (eg. HCl/HBr)

N.B. Dihaloalkane formed when X2 (eg. Cl2) used (X-X bond instead of H-X)

Alkene ---> Alcohol = Electrophilic Addition/Hydration

Double bond moves to H and H-O bond moves to O-

Lone pair of O-SO3H moves to C+ to form alkyl hydrogen sulphate

1st H + O (from H2O) + SO3H = H2SO4 and 2nd H+ + alkyl group-O --> alcohol 

Condtions = Conc. H2SO4, then H2O (OR H2O w/H3PO4 catalyst at 330C)

1y Alcohol ---> Aldehyde ---> Carboxylic acid = Full Oxidation

Orange Dichromate ions --> Green Chromium ions

Conditions = K2Cr2O7 w/dilute H2SO4 and distil (partial) written as [O]

                     Excess K2Cr2O7 w/dilute H2SO4 in reflux (full) written as 2[O]

2y Alcohol ---> Ketone = Partial Oxidation

Orange  Dichromate ions --> Green Chromium ions

Conditions = K2CR2O7 with dilute H2SO4 in distillation written as [O]

Alcohol ---> Alkene = Elimination

Small molecule leaves (eg. H2O: OH and H from neighbour C leave)

Conditions = Hot conc. H2SO4 OR AL2O3 at 600K OR H3PO4

Aldehyde/Ketone ---> Hydroxynitrile = Nucleophilic Addition

Lone pair of nucleophile goes to C+ and C=O bond moves onto O-

Lone pair on O- moves to H+

Conditions = Acidified NaCN/KCN (NOT HCN because it's a toxic gas)

Aldehyde ---> Carboxylic acid = Oxidation (See Card 5)

Aldehyde/Ketone ---> Alcohol = Reduction (Nucleophilic Addition)

Same mechanism as above

Conditions = NaBH4(aq) written as 2[H]

Carboxylic Acid ---> Metal salt

RCOOH(aq) + NaHCO3(aq) --> RCOO-Na+(aq) + H2O(l) + CO2(g)

Conditions = NaHCO3(aq)/(s) OR Na2CO3(s)

Carboxyic Acid ---> Ester = Condensation/Esterification

RCOOH + R'OH <--> RCOOR' + H2O

Conditions = Hot conc. H2SO4 catalyst + R'OH

Ester ---> Carboxylic Acid + Alcohol = Hydrolysis

H2O = weak nucleophile

Conditions = Heat w/dilute H2SO4

                     Base (eg. NaOH) forms acid salt + water (reaction to completion)

Acyl chloride ---> Carboxylic Acid etc = Addition-Elimination/Acylation

Lone pair on nucleophile goes to C+ and C=O bond moves onto O-

Lone pair on O- moves to C-O bond and C-Cl bond moves onto Cl (breaks off)

Nu-H bond moves onto Nu+ and H+ breaks off (toxic HCl given off)

Conditions = H2O (Carboxylic Acid = hydrolysis), ROH (Ester = condensation), NH3=best nucleophile (Amide) and 1y amine (N-substituted Amide)

Acid Anhydride + H2O ---> Carboxylic Acid + Carboxylic Acid

                              ROH ---> Carboxylic Acid + Ester

                              NH3 ---> Carboxylic Acid + Amide

                              1y Amine ---> Carboxylic Acid + N-substituted Amide

Benzene ---> Nitrobenzene = Electrophilic Substitution/Nitration

Delocalised electrons move to NO2+ and forms a semi-circle with + in benzene ring

C-H bond moves into semi-circle in the ring and H+ breaks off (makes toxic HCl)

Conditions = Conc. H2SO4 and conc. HNO3 at 50C

Benzene ---> Acyl substituted arenes (Eg. Phenylethanone) = Electrophilic Substitution/Friedel-Crafts Acylation

Same mechanism (delocalised electrons move to the RCO+)

Conditions = AlCl3 catalyst and acyl chloride

Haloalkane ---> Nitrile ---> 1y Amine = Nucleophilic Substitution + Catalytic Hydrogenation/Reduction

Step 1 = Nucleophilic Substitution with KCN in aqueous ethanol with heat

Step 2 = R-CN + 2H2 --> R-CH2NH2

Conditions = Ni/H2 (Haloalkane + NH3 --> mixture of 1y-4y amines)

                    LiAlH4 in ethoxyethane solvent

Benzene ---> Nitrobenzene ---> Phenylamine = Nitration + Reduction

Step 1 = Electrophilic Substitution with conc. H2SO4 and conc. HNO3 at 50C

Step 2 = <O>-NO2 + 6[H] --> <O>-NH2 + 2H2O

Conditions = Sn/HCl, followed by NaOH at room temperature

Amine---> Salt

RNH2 + H+ + Cl- --> RNH3+ + Cl-

Conditions = Dilute HCl (excess with phenylamine)

Salt ---> Amine

<O>-NH3+ + Cl- + OH- --> <O>-NH2 + Cl- + H2O

Conditions = Strong base (Eg. NaOH)

N.B. Inductive effect makes better base (electrons lost more easily) and <O> pulls electrons towards it, so:

(3y amine is insoluble) 2y amine > 1y amine > Ammonia > Phenylamine

Amino Acid + Amino Acid ---> Dipeptide = Condensation

H2O comes out and CONH amide bond formed

N.B. Polypeptides = Polyamides

Dipeptide ---> Amino Acid + Amino Acid = Hydrolysis

Conditions = H2O with HCl and a catalyst

N.B. Amino acids can be separated by paper chromatography

Alkene ---> Poly(alkene) Polymer = Addition

Double bond opens and joins with alkene on either side (ONE product formed)

Conditions = Alkenes

Diol + Dicarboxylic Acid ---> Polyester = Condensation

H2O (small molecule) removed and O-C bonds formed = 2 products

Conditions = Diols and Dicarboxylic Acids

Diaminoalkane + Dicarboxylic Acid ---> Polyamide = Condensation

H2O (small molecule) removed and CONH bonds formed = 2 products

Conditions = Diaminoalkanes and Dicarboxylic Acids

N.B. Benzene attached to a monomer makes a polymer (w/Zeigler catalyst)

Oxidising

K2Cr2O7 acidified (dilute H2SO4) = 1y Alchols -> Aldehydes -> Carboxylic acids

                                                         2y Alcohols -> Ketones

Reducing

NaBH4 ---> H- (for C=O in aqueous soln.) = Aldehydes -> 1y Alcohols

                                                                     Ketones -> 2y Alcohols 

H2/Ni = Nitrile -> 1y Amine

Sn/HCl (Sn/H+) = Nitrobenzene -> Phenylamine

Dehydrating

Al2O3 (with heat) OR H3PO4 OR hot conc. H2SO4 = Alcohol -> Alkene

Aliphatic

Higher alkane --> Lower alkanes and alkenes = Catalytic Cracking

Conditions = Al2O3 + SiO2 catalyst at 500C

Carboxylic acid --> Acyl chloride = Nucleophilic substitution

Conditions = PCl5

Nitrile --> Carboxylic acid = Hydrolysis

Conditions = Heat with dilute H2SO4

Aromatic

Benzene --> Cyclohexane = Reduction

Conditions = Ni/H2 at 150C

Phenylamine --> (Phenyl) Amide = Addition-Elimination/Acylation

Conditions = Ethanoyl chloride