Organic Reactions Flashcards
Radical sub
Alkane + halogen = halolakne
Intiation = halogen to 2 radicals due to energy from UV rays from sun
Propagation
Radical + alkane = alkane radical + h halogen
Alkane radical + halogen = halogen radical + new product
Termination = any radicals combining
1) substition at differnt points ( differnt isomers formed)
2) further substitution
These both tend away from the product you desire, not a good way to make Halolakanes basiclaly
Alkene + hydrogen
Conditions
Alkane , 423k nickel catalyst
Alkene + water
Alcohol but water must be steam, conc phosphuric acid catalyst
Alkene + hydrogen halide / halogen
Halolakane
Electrophilic addition
Csn form 2 products, use markownikoff rule / stability to determine
1) primary alchol oxidise to aldehyde
CONDITIONs, catalysts, colour changes, products and reactants
Heat under DISTILLATION
Requires [O] and acidified potassium dichromate as catalyst
Produces ONE H2O when aldehyde made
Orange to green
Primary alchol oxidise to carboxylic
Heat under REFLUX with excess H2So4/ K2cr2o7
Alchol + 2[O] becomes carbox and 1 water again
Secondary alchol oxiside to ketone
Reflux
Acidified dichromate
1 O , 1 water
Dehydration alcohol
Alcohol to alkene, and water
Phosphoric acid conc catalyst
Heat under reflux
Substitution with hydrogen halide
Alchol becomes halolakane
-react with NAhalide and H2so4 under reflux
- hydrogen halide produced in vitu
- this reacts and substitutes to make halolaken and water
Halolakane + / NAOH
(AQEOUS alkali)
Becomes Alcholo again by NUCLEOPHILIC substition restcion
Nitration of benzene
REACTANTS AND CONDTIONS EXACT
Show the role of catalyst
50°
H2SO4 CONCENTRATED catalyst
CONCENTRATED nitric acid
Electrophikic substition
1) HNO3 + H2SO4–> NO2 + + Hso4- + h2o
Then H+ + Hso3 - —> H2So4 regenerated again
Halogenation of benzene
Show role of catalyst
Alkylation
Acylstiom
Resctsnt needed, products
Rewuired halogen carrier of same type
1) br 2 + AlBr3 —> AlBr4 - + Br +
2) H+ + AlBr4- —> HBr and AlBr3 regenerated
Alkylation = haloalkane and carrier
- extends the carbon chain
Acylation = ACYL CHLROIDE and carrier
- creates an aromatic ketone !
How to distinguish between phenols and carboxykic acids and why
Phenols are very weak acids, carbox is strong weak acid
Thus phenols can’t react with weak base like cabrinste
So react both with carbojsbte, which ever effervescence is CARBOX
Phenol and bromine water reavtion
1) observation (IMPORTANT)
2) new reaction condtions
This takes place WITHOUT halogen carrier
And forms up to 3 substations
This DECOLOURISES bromine water this time forming a WHITE PRECIPITATE TOO
Nitration of phenol
New condtions
What products made?
1) weak nitric acid + NO SULFRIC acid catalyst + ROOM TEMP
- however can only happen once before ewd effect takes place
Still does 2,4 so two compounds can be made
Why are phenols MORE reactive than benzene, and as a result can deoclorusie bromine water etc
- the lone pair on the oxygen on OH group partially delocalised into the SYSTEM OF PI BONDS
- this increases the electron density of the pi ring
- as a result the electron density on average around any 2 carbons is MORE than regular benzene
- so can induce a STRONGER dipole , and thus is less more susceptible to electrophilic attack
= therefore can easily deoclorusie bromine
What key phrase mention for why phenol / alkene better than benzene?
More susceptible to electrophikic attack !
What do electron withdrawing groups / activating groups do
Ewd reduced electron density, meaning harder to react now with electrophiles ( higher temps, cstksydtd needed)
Activating activated the system of pi bonds ( ring) and increases electron density making easier to react with nicer conditions
Ewd and activating groups we must know SPEC
Nh2 is activating
oh activating (obviously)
No2 is deactivating
What groups are 2 4 directing and what groups are 3 directing
All activating are 2 4 , except halogens which are DEACTIVSTIMG and 2 4
All deactivating are 3
ORGANIC SYNTHESIS, MAY FORM 2 PRODUCTS DUE TO 2 4 DIRECTING, WHAT TO MAKE SURE TO DO
Must make sure to SEPARATE THESE
Describe the resitivity of a carbonyl group and thus what reactions it takes part in
It has a double bond, so thing it would react like an alkene?
- the bond is POLAR HOWEVER due to electronegativity differences.
- therefore it can attract NUCLEOPHILES
And thus take part in NUCLEOPHILIC ADDITION REACTIONS
Reduction of ketoje , aldehyde , both ways
Reactants
By NABH4/ h20, 2 H , makes alcohols
By NACN/ H+. 2 H, makes hydroynitriles
How to make acyk chloride
SOCl2 thinkyk chloride + carboxylic acid = acyl chrlodie
Produced so2 and hcl so use fume cupboard as toxic
4 reactions of acyl chlroide
1) alcohols ester
2) phenols ester (only acyl + acid anhydride can do as reactive enough , carbox isn’t)
3) water = carbox
4) ammonia = primary amide, primary amine = secondary amide
Reactions of acid anhydide
Same as ester ( alchol phenol ester, water cabroxykic , ammonia amine amides)
Less reactive however, could be preferred on lab setting
Acid and base hydrolysis
What produced, how to do acid
Acid = hot aqueous acid , returns alchol and carbox
- reflux with water and sukfuric acid , reverse of esterificsrion and reversible In general
AKLAI = hot aqueos base = returns alchol and a SALT
of the carboxylate ion ( irrevsibke hence)
How ti make ester
Alchol + carbox , sukfuric cinc catlsydt , heat up
Or ester / acid anhydide with phenol /alcohol too
