Hydrocarbons Flashcards
Alkanes are also known as
Parrafins
Order of free radical substitution
Zero order
Alkenes are also known as
Olefins
__________ substitution mostly occurs in benzene
Electrophilic
_________ addition occurs in alkenes/alkynes
Electrophilic
_________ addition occurs in aldehydes/ketones
Nucleophilic
p1 mechanism is also known as
a-ß or 1,2 elimination
p2 mechanism is also known as
a-elimination or 1,1 elimination
A common name for ethanol is
Spirit of wine
Catalysts used for dehydration of alcohols (Alcohol —> Alkene + water)
H2SO4
H3PO4
Al2O3
P4O
Rate of reaction of alcohols in order of slowest to fastest
Primary < Secondary < Tertiary
%ages of H2SO4 needed fro each º of alcohol
Primary: 75%
Secondary: 60%
Tertiary: 20%
Temperature needed for each º of alcohol
Primary: 140-170º
Secondary: 100º
Tertiary: 80º
Temperature for hydrogenation reaction with Ni catalyst
250º-300º
Temperature for hydrogenation reaction with Pt/Pd
25º
Identification test for Alkene
Bromination (brown becomes colorless)
What is Visceral dihalide also known as
Dutch liquid (bc its oily)
Order of hydrohalogens
HF «_space;HCL < HBR < HI
Order of stability of º hydrohalogens (HX)
Tertiary > Secondary > Primary (because tertiary has 3 e- donating groups)
What is Markonikov’s law
When assymetrical, the partial positive is added to the C with more Hydrogens (pos = more)
What is Karasch rule? What is it also called?
Its the anti Markonikov rule, and adds the opposite way when a peroxide is present. Its also known as the Peroxide effect.
Catalyst used for polymerization
TiCl4 or Al(C2H5)3
Baeyer’s test
Add KMnO4. If purple to colorless, that means alkene is present.
Alkene + KMnO4 —>
glycol
What is ozonalysis for
Checks position of double bond
Alkene + ozone —>
Monozonide (highly unstable) —> ozonide
Ozonide + H2O and Zn —>
Aldehyde/Ketone
Alkynes are also known as
Acetylenes
Which alkyne does not exist
Methylene
Reactivity of alkynes
Alkene (more reactive) > Alkyne > Alkane (least reactive)
Which alkyne is most acidic
Terminal Alkynes (1-alkyne)
Terminal alkyne + bases —>
Alkylides
Non terminal alkynes are
not acidic
Ammonial cupourous chloride test (Terminal + that)
Gives red ppt (CuC - CCu) (- is a triple bond)
Terminal alkyne + NaNH2 (strong base)
NH3 + R-C- - - C-Na+
Terminal alykne + ammonium silver nitrate gives
White ppt (AgC-CAg) (triple bond)
Red ppt (CuC-CCu) + H2SO4 gives
Ethyne (Acetylene)
To get only alkene from alkyne what do you use?
Lindlar’s catalyst (Pd(BaSO4) or Quinoline
Assymetrical alkynes follow Markonikov’s rule in
Both steps 1 & 2
Symmetrical alkynes follow Markonikov rule in
Only step 2
Which alkyne gives what aldehyde/ketone?
Ethyne gives Aldehyde. All other alkynes give Ketones.
Huckel #
(4n+2) πe-
What is the structure of naphthalene
2 fused benzene rings
What is the name of three fused benzene rings
Anthrasene
Who obtained benzene from cold tar
Hoffsman
How did Faraday obtain benzene
Destructive distillation of vegetable oil
Geometry of benzene
Trigonal planar
Hybridization of benzene
sp2
C double bond C length
1.34 Aº
C single bond C length
1.54 Aº
C triple bond C length
1.20 Aº
C-H bond length
1.09Aº
Avg C-C bond length in benzene
1.39 Aº
Which resonating structures contribute more to the real structure (resonance hybrid)? How much percentage?
Kekule structures . 39%
What resonating structures contribute less to the resonance hybrid? How much percentage?
DeWar’s structures. 7.3%
Which is more stable resonating structure, charged/ionic or neutral
Neutral
Resonance energy =
[Energy of stable canonical] — [Energy of resonance hybrid (real structure)]
What is the most stable canonical form of benzene?
Cyclohexa-triene
Resonance energy of benzene?
152 kJmol
CH3 is an electron ________ group
Donating
Names of CH2Cl, CHCl2, and CCl3 respectively
Benzyl chloride, benzal chloride, benzo trichloride
What is the catalyst used in the oxidation reaction of benzene? At what temperature?
VsO5 at 400-500º
Oxidation reaction of benzene makes _________ then __________
Maleic anhydride then maleic acid (but-2-ene dioic acid)
Catalyst for aromatic electrophilic substitution of benzene?
AlCl3 / FeCl3 / BCl3 (Lewis Catalyst Acid)
Order of reactivity of hydrocarbons
Alkene > Benzene > Alkyne > Alkane
Other names of Benzene + Electrophile Intermediate
Sigma Complex, Willard’s complex, Benzenium ion, Arenium ion, Cyclohexadienyl ion
Nitrating mixture for nitrogenation of benzene
NHO3 (conc) + H2SO4
Conditions for nitrogenation of benzene
Nitrating mixture (NHO3 + H2SO4), H2SO4 catalyst at 60º
Chances of OMP nitrogenation
63% ortho, 3% meta, 34% para