Alkadienes Flashcards
PALATANDAAN in naming ALKADIENES
in terms of:
- suffix
- parent chain (straight-chain) [2]
- parent chain (cyclo) [1]
- -diene
- longest chain that passes thru ALL C ATOMS in BOTH double bonds (with all the double bond carbons having the lowest number)
- indicate position of double bond before the parent name
- prioritize giving the 2 pairs of double bond carbons the lower position number
IN CYCLOALKADIENES
should the parent chain have a multiplier?
no, multiplier is only applicable to substituents
e.g.
2,4 - dimethyl - 1,3 - butadiene
How many set of C=C do alkadienes have?
+ general formula
2 sets
Cn H2n-2
3 TYPES of ALKADIENES
+ which is the most stable? + reason
- Isolated Diene
- Cumulated Diene
- Conjugated Diene - most stable due to conjugation
ALKADIENE TYPES
ISOLATED DIENES
- C=C are ____ by ____ or ____ _____
- ____ bonds in these compounds react ______ of each other
- separated
- 2 or more C-C bonds
- double
- independently
ALKADIENE TYPES
CUMULATED DIENES
- has ______ bonds that are on ____ _____
- C=C
- adjacent carbons
ALKADIENE TYPES
CONJUGATED DIENES
- their _____ are separated by ____ C-C bond
- C=C
- 1 C-C bond
in a (single) double bond, how many of the ff are there?
- p orbitals
- π bond
- 2 p orbitals (1 per C in the C=C)
- 1 π bond (fused from the 2 p orbitals)
CONJUGATION
- occurs when ____ orbitals ____ in ____ or _____ _____ atoms
- the _____ density in each of the ____ bonds is ______ (or spread across) in a large volume
- consequences ^^ (2)
- p orbitals
- overlap
- 3 or more adjacent atoms
- electron
- π bonds
- delocalized
*since may overlapping p orbitals - mag s-spread across yung electrons
- thus, lowers energy of molecule
- molecule becomes more stable
____ dienes and _____ absorb light in the ____ region ( ___ - ___ nm)
if molecules have ____ or more conjugated π bonds, they will absorb light in the ___ region instead + emit the light it ____ ____ absorb
example of ^^
- conjugated
- polyenes
- UV
- 200 - 400 nm
- 8 or more
- visible
- does not
LYCOPENE - appears red
ELECTROPHILIC ADDITION
isolated alkadienes
- consumes ___ mol of the reagent per ___ + reason?
- ___ change in the ____ of the double bonds
- how many products are formed?
+ SAMPLE if reagent is:
1.) Br2
2.) 2 Br2
- 1 (so 1 mol of reagent will affect ONLY 1 C=C)
- C=C
*since C=C reacts independently in isolated dienes, each C=C will undergo an independent electrophilic addition
- no
- position
- usually 1 product is formed
+ base on notes
ELECTROPHILIC ADDITION
conjugated alkadienes
- draw the 2 possible products
- which of the two is more stable?
- which of the two is typically the major product?
1.) 1,2-addition product (major product - more stable)
2.) 1,4-addition product
in electrophilic addition in CONJUGATED ALKADIENES, when can a 1-product rxn occur instead of a 2-product?
Negative (low) Temp: 1,2-addition product
Positive (high) Temp: 1,4-addition product
**if temp is given, only 1 product can occur
ELECTROPHILIC ADDITION
conjugated alkadienes
- recall process of 1,4-addition product
- WHAT process is this ^^ based on?
- this ^^ process is _____-stabilized
- draw the process
- allylic carbocation: resonance-stabilized
ALLYLIC vs VINYLIC carbon
+ which is more stable + reason
ALLYLIC - carbon adjacent to a C=C (more stable due to resonance stabilization)
VINYLIC - carbon that IS A PART of the C=C
PALATANDAAN in reactions in alkadienes
mechanism is similar to alkenes, may exceptions or added info lang which is yung mga stated here
+ identify first if isolated or conjugated yung rxn before finding the products
ELECTROPHILIC ADDITION
conjugated alkadienes
- are its products always only 2?
no, nakadepende sya sa equivalent H atoms attached to each C in the C=C
so if same lang yung molecule kahit i mirror or baliktarin mo siya, counted as 1 sya
CONJUGATED DIENES
difference between its ELECTROPHILIC ADDITION and FREE RADICAL ADDITION
EA: major product is usually 1,2-addition product
FRA: major product is usually 1,4-addition product
FREE RADICAL POLYMERIZATION
- is also called??
- wherein an _____ ____ adds to the ____ to form a ____ ____, which then ____ with ______ ______ molecules
- process is similar to ______?
- how to name?
+ draw sample
- chain growth polymerization
- initiator radical
- C=C
- reactive intermediate
- reacts
- succeeding monomer
- 1,4-addition product
- also add “poly” to the beginning
REAL LIFE application of free radical polymerization in Alkadienes
polychloroprene
- first successful rubber substitute in the US
- forerunner of present-day plastic industry
