Index File of Organic Chemistry Reactions
Combustion
CxHyOz + ? O2  x CO2 + y/2 H2O
Anything Organic will burn (if you try hard enough) in the presence of
oxygen. Products are always CO2 and H2O, in the appropriate
proportion. Reaction is exothermic.
Reaction first encountered in CHEM 121.
Chapter 2: Alkanes
Radical halogenation
CxHy + X2 + heat or h  CxHy-1X + HX
X = F, Cl, Br, or I. Substitution reaction—the halogen substitutes for a
hydrogen on the hydrocarbon. Only happens in the presence of heat or
light. Cl and Br are most common; F is fast enough to be dangerous, I is
too slow to be practical. Mechanism involves radicals.
Product above is that of monohalogenation; it is difficult to stop at just
one substitution and additional products include CxHy-2X2 … CxXy.
Chapter 2: Alkanes
Hydrohalogenation
R2C=CR2 + HX  R2CH—CR2X
R’s may be C’s or H’s. X = F, Cl, Br, or I. Addition reaction—the H
adds to one side of the double bond, the X adds to the other.
Addition follows Markovnikov’s rule in that the hydrogen goes on the
less substituted C, the halogen on the more substituted carbon.
Mechanism: goes through a carbocation intermediate; the relative
stability of which (3o > 2o > 1o) explains Markovnikov’s rule.
Chapter 3: Alkenes and Alkynes
Hydration
R2C=CR2 + H2O  R2CH—CR2OH
R’s may be C’s or H’s. Addition reaction—H adds to one side of the
double bond, OH adds to the other.
Requires an acid catalyst (H2SO4) to work. Addition follows
Markovnikov’s rule in that the hydrogen goes on the less substituted C,
the hydroxy on the more substituted carbon.
Mechanism: goes through a carbocation intermediate; the relative
stability of which (3o > 2o > 1o) explains Markovnikov’s rule.
Chapter 3: Alkenes and Alkynes
Halogenation
R2C=CR2 + X2  R2CX—CR2X
R’s may be C’s or H’s. X = F, Cl, Br, or I. Addition reaction—one X
adds to each side of the double bond.
Halogens add trans to each other. Common solvent is CH2Cl2.
Mechanism: variation on the carbocation intermediate theme.
Chapter 3: Alkenes and Alkynes
Hydrogenation (reduction)
R2C=CR2 + H2  R2CH—CR2H
R’s may be C’s or H’s. Addition reaction—one H adds to each side of
the double bond.
Requires a transition metal catalyst, such as Pt, Pd or Ni, and generally
reduced pressure. Hydrogens add cis to each other.
Mechanism utilizes the surface of the metal catalyst to bring the
hydrogens and the alkene together.
Chapter 3: Alkenes and Alkynes
Polymerization
n R2C=CR2  (CR2—CR2)n
R’s may be C’s or H’s. Addition reaction of sorts—another alkene unit
adds to each side of the double bond, repeating to convert many
monomers (alkenes) to a polymer (long alkane).
Requires a radical initiator; something which makes a radical easily,
along with the energy (heat, light) to allow it to do so.
Plastics!
Chapter 3: Alkenes and Alkynes