Reaction Methodology Flashcards
Substitution reaction for aromatic compounds
Hydrogen halides and water don’t react with benzene
Cl2 Br2 do not add, the substitute one of the hydrogen atoms –> preserves rings
Friedel-Crafts Reaction
Benzene + alkyl chloride –> alkylated hydrocarbon + HCl
In presence of AlCl3 catalyst
Condensation Polymers: Polyamides
Formed from a dicarboxylic acid and a diamine
Condensation Polymers: Polyesters
Formed from a dicarboxylic acid and a diol
Condensation polymers
Polyesters and polyamides
Addition polymers
Polyalkenes and polydienes
Hydrogenation (energy of delocalization of pi electrons
Only addition reaction that aromatic hydrocarbons can undergo
Heat from the hydrogenation of benzene is less than the predicted energy of breaking three C=C bonds (difference= energy of delocalization of electrons)
Formation of ethers
Formed by condensation reactions from alcohols
Halogenated hydrocarbons
F, Cl, I, Br substitute H on hydrocarbons
Para-
Symmetrical/opposite of (1,4)
Meta-
Skips one between (1,3)
Ortho-
Next to (1,2)
Nitration of aromatic compounds
Benzene + HNO3 (or HONO2) –> nitrobenzene + H2O
(H2SO4 catalyst is required)
Aromatic compounds can interact with HNO3 or HONO2 to produce nitro derivative (benzene with a NO2 group) and water
Substitution reactions for aromatic compounds
benzene + Br2 –> bromobenzene + HBr (requires FeBr3 or FeCl3 catalyst)
One of the halogen atoms is substituted for a H atom, the other joins with the replaced H atom to form HX
Oxidation of alcohols to ketones and aldehydes
Require catalyst – K2Cr2O7 in acidic solution
Need equivalent of one oxygen atom to convert alcohol to aldehyde or ketone, depending on where hydroxyl group is
Preparation of carboxylic acid
Oxidize aldehyde to a carboxylic acid
Requires Cr2O7(2-) in acidic medium, need equivalent of one oxygen
Hydrolysis of amides
Reaction with water, amides can be hydrolyzed back to parent carboxylic acid and amine (may require acid to catalyze)
Carbonylation of methanol
CH3OH + CO (g) –> CH3COOH (requires Rh complex catalyst)
Used for preparation of acetic acid, not other carboxylic acids
Saponification of esters (base hydrolysis)
RCOOR’ + NaOH -> RCOO-Na+ + R’OH
Reaction between an ester and a strong base (basically irreversible process)
Formation of esters
Carboxylic acid + alcohol –> ester
Catalyzed by strong acid (H2SO4)
Reversible process
Formation of carboxylic acids part 2
Oxidize alcohol to aldehyde then oxidize aldehyde to carboxylic acid with excess K2Cr2O7
Addition reactions for alkenes
Break double (pi) bond, add halogens, hydrogens (hydrogenation), hydrogen halides, H2O
Hydrohalogenation of alkenes/alkynes
Break double bond, add H or X to each C
Hydration of alkenes/alkynes
Break double bond, add H or OH to each C (in acidic medium)
pH-dependent redox potentials
half-rxns that don’t include OH- or H+ are pH-independent, ones that do are pH-dependent
So O2 is a stronger oxidizer in acidic medium than in basic medium
