CARBONYL Flashcards
explain solubility of carbonyl compounds as the carbon chain length increases
Solubility decreases as relative molecular mass increases, and the predominant t idid int and steric hindrance of the bulky alkyl groups reduce the extent of H bonding w/ water molecules
Explain all synthesis of carbonyl compounds
1) [O] of primary alcohol -> aldehyde
2) [O] of secondary alcohol -> ketone
3) Vig [O] of alkenes -> ketone
Why does phenol not react with carboxylic acids
The LP of e- on the O atom in phenol is delocalised into the BZ ring, making it less available to attack the protonated carbonyl carbon of the carboxylic acid
Describe the iodoform test
Warm each sample with aqueous alkaline iodine. A yellow ppt is formed for __ but no ppt is observed for ___
Why is LiAlH4 a stronger RA than NaBH4
Al is less electronegative than B. A H atom bonded to A/ in A/H4 has a large partial negative charge (&-) and is thus more nucleophilic than a H aton bonded to B in BH4 .
Why does C=O undergo Nu Add but C=C does not
In C=O, the carbonyl carbon is e-def as it is bonded to a highly EN O atom, attracting the CN- nucleophile.
The non-polar C=C bond is e-rich as there is no EN diff b/w the two C atoms.
Why can’t LiAlH4 reduce C=C
LiAlH4 produced a hydride nucleophile whoch is repelled by the e- rich C=C bond in ALR je e
Why is resultant mixture optically inactive for Nu Add of CN-
Since the aldehyde is (trigonal) planar around the carbonyl carbon, therè is an equal probability of the Nu CN- ion attacking the E+ carbonyl carbon from the top of the plane as well as from the bottom. A racemic mixture is obtained.
