reactions of hydrocarbons: combustion
DESCRIPTION
Reactions of Hydrocarbons: Combustion. 2 CH 3 CH 2 CH 2 CH 3 ( g ) + 13 O 2 ( g ) → 8 CO 2 ( g ) + 10 H 2 O( g ) CH 3 CH=CHCH 3 ( g ) + 6 O 2 ( g ) → 4 CO 2 ( g ) + 4 H 2 O( g ) 2 CH 3 C CCH 3 ( g ) + 11 O 2 ( g ) → 8 CO 2 ( g ) + 6 H 2 O( g ) Anything that contains carbon and hydrogen - PowerPoint PPT PresentationTRANSCRIPT
Reactions of Hydrocarbons: Combustion
2 CH3CH2CH2CH3(g) + 13 O2(g) → 8 CO2(g) + 10 H2O(g)
CH3CH=CHCH3(g) + 6 O2(g) → 4 CO2(g) + 4 H2O(g)
2 CH3CCCH3(g) + 11 O2(g) → 8 CO2(g) + 6 H2O(g)
Anything that contains carbon and hydrogen (and often other elements)
Reactions of Alkanes: Substitution
CH3CH3 + Br2 ® CH3CH2Br + HBrlight
CH3CH2CH2CH3 + Br2 → many productslight
Hydrogenation: addition of H2 (with metal catalyst: Pt, Pd, Ni)
CH2=CHCH3 + Br2 ® CH2BrCHBrCH3
CH2=CHCH3 + H2 ® CH3CH2CH3Pt
Halogenation: addition of X2 (Cl2, Br2, I2)
Alkene/alkyne addition reactions
+ H2 ® Pd
Hydrohalogenation (addition of HX, X = F, Cl, Br, or I)
CH2=CHCH3 + HBr ® CH3CHBrCH3
+ H2O ®
Hydration (addition of H2O, or H + OH)
Markovnikov addition: “The rich get richer” Carbon that starts with more hydrogens gets the additional hydrogen(s)
+ 2HBr ® Br Br
OH
H+
Alkene/alkyne addition reactions, cont.
Oxidation of alkenes
KMnO4 (aq)
Cold, dilute
OH
OH
In organic chemistry: Oxidation: carbon adds oxygen and/or loses hydrogenReduction: carbon loses oxygen and/or adds hydrogen
also an addition reaction
KMnO4 (aq)
Hot, concentrated
Oxidation of alkenes, cont.
O
OH
O+
KMnO4 (aq)
Hot, concentrated
OH
O
O
Reactions of aromatic compounds
Substitution:Halogenation (with Cl2 or Br2 and Fe catalyst)
Cl
Fe + HCl+ Cl2
Oxidation (of alkyl benzene at the first alkyl carbon)
Reactions of aromatic compounds, cont.
COOH
KMnO4 (aq)
hot, conc.
Reactions with Alcohols
Elimination (backwards of addition) e.g. Dehydration
HOH2SO4
HOH2SO4 No reaction
Reactions with Alcohols, cont.
• Oxidation 1° alcohols aldehydes, carboxylic acids2° alcohols ketones3° alcohols NO REACTION
HO
KMnO4 (aq)
HO
O
OH
KMnO4 (aq)
O
OH KMnO4 (aq)
No reaction
KMnO4 (aq)
No reactionAlso note:
Reactions with Alcohols, cont.
• Reduction (for 1°, 2° or 3°)
2 HO-R + 2 Na 2 NaOR + H2 (g)
recall: 2 Na + 2 H2O 2 NaOH + H2 (g)
Phenol as an acid
+ NaOH
ONa
+ H2O
Strong baseWeak acid
Acid/base reaction
Reactions of Aldehydes and Ketones
Oxidation of aldehydes to carboxylic acids:
RCHO RCOOHKMnO4 (aq)
O
KMnO4 (aq)
O
HO
Reactions of Aldehydes and Ketones, cont.Reduction of aldehydes and ketones to alcohols primary and secondary alcohols
Several possible catalysts, a few examples:
O OH+ H2
Ni
O OH+ H2
Pd
Reactions of carboxylic acids
Acid/base reactions:
sodiumacetate
sodium pentanaote
HO
O+ NaOH
NaO
O+ H2O
HO
O+ NaOH
NaO
O+ H2O
acetic acid
Esterification:
Reactions of carboxylic acids, cont.
Amine Reactions
• Amines are weak organic bases.– Will react with strong acids to form ammonium
saltsRNH2 + HCl → RNH3
+Cl−
(recall: NH3 + HCl → NH4+Cl− )
When they react with carboxylic acids in a condensation reaction, an amide is produced.
OH
O
R + NHR3 NR2
O
R + H2OHeat
OH
O+ CH3NH2 NHCH3
O+ H2O
Heat
OH
O+ NH3 NH2
O+ H2O
Heat
Amide formation from reaction of primary or secondary amines or ammonia with carboxylic acid:
1° amine 2° amide
1° amideammonia
Amine Reactions, cont.
Hydrolysis of esters and amides
OH
O+ CH3NH2
NHCH3
O+ H2O
H+ (aq)
O-K+
O+ CH3NH2NHCH3
O+ KOH(aq)
OH
O+ CH3CH2OHO
O
+ H2OH+ (aq)
Water (with acid or base) breaks the ester and amide linkages.