ALDEHYDES, KETONES

simplest aldehyde

methanal (formaldehyde)

how to name aldehyde

no need to use number to locate aldehyde group

how to name unsaturated aldehyde

becomes enal

where is co (carbonyl) in aldehyde

end

where is co (carbonyl) in ketone

middle

polarity of ketone and aldehyde

polar (c=o is polar, O partially negative)

strength of intermolecular bond aldehyde and ketone

weak intermolecular attraction between partial positive charge of c=o and weak negative of another c=o

is hydrogen bonding possible between aldehyde and ketones and why

no.

no polar CO or NH bonds

boiling point ketone, aldehyde

lower than alcohol and carboxylic acid

how does aldehyde become carboxylic acid

oxidizing agents like potassium dichromate

what are liquid aldehydes sensitive to

oxidation via o2 air

how do ketones resist oxidation

oxidizing agents like potassium dichromate and molecular oxygen

reagent example for oxidation of aldehydes

tollens. silver dposits on walls on container as silver mirror

reduction (loss of oxygen gain of hydrogen) of aldehyde gives

primary alcohol. becomes C(H)OH group

reduction (loss of oxygen gain of hydrogen) of ketone gives

secondary alcohol. becomes C(H)OH group

reagent example for reduction of aldehyde/ketone

sodium borohydride (NaBH4)

hydrogen (hydride) adds to partially positive carbon in c=o

leaves negative charge on oxygen in c=o

what gives the primary/secondary alcohol with NaBH4

reaction with aqueous acid

what does NaBH4 not affect structurally

carbon carbon double bond, or aromatic ring

biological systems: agent for reduction of aldehydes and ketones

nadh (BIO HL TRAUMA.). delivers hydride to carbon in c=o of aldehyde/ketone

carbon bc: think of bio hl

describe reduction of pyruvate

done w nadh, gives lactate. end product of glycolysis (oxidation, lol!)

hemiacetal

addition of alcohol to carbon group of aldehyde/ketone (half acetal)

describe hemiacetals

unstable, minor component of equilibrium mixture

how does cyclic hemiacetal exist (3 things)

OH, C=O, 5 to 6 carbon ring

how are acetals formed

hemiacetal + alcohol. acetal formed along w water

all steps in hemiacetal and acetal formation are

reversible

enol

aldehyde/ketone with hdyrogen on alpha carbon, in equilibrium with constitutional isomer (different bonding)

alpha carbon

carbon near carbonyl group

alpha hydeogen

hydrogen near the carbon that's near the carbonyl group

what form dominates in keto enol equilibrium

keto form

acetal formation (6)

1. hydrogen proton added to oxygen in c=o -> carbon in c=o becomes stronger electrophile but more susceptible to nucleophile attack

2. electrophile + nucleophile = covalent bond. adds first OR group required for acetal formation. intermediate = oxonium.

3. hydrogen proton transferred to another oxygen

4. bonds break to form stable molecules/ions

5. electrophile + nucleophile = covalent bond. OR group added to carbonyl carbon

6. proton talen away. regenerates H+ = acetal

stuff i dont get in chem lec

secondary alcohol oxidizes to

ketone

aldehyde reduces to

primary alcohol

ketone reduces to

secondary alcohol

carboxylic acid reduces to

primary alcohol

general formula of aldehyde:

R-CHO (H attached near C=O) * is this true

oxidation: alcohol vs. aldehyde

primary alcohol oxidates -> aldehyde/ketone

aldehyde oxidates -> carboxylic acid

primary alcohol -> aldehyde -> carboxylic acid

reduction: alcohol vs. aldehyde

alcohol reduces -> alkane

aldehyde reduces -> primary alcohol

important reactions for structures: NAME THE PROCESSES (4)

1. oxidation

2. reduction

3. acetal formation

4. hemiacetal formation

how to understand structural reaction for aldehyde/ketone stuff

track carbonyl CARBON

⁃ oxidation adds oxygen or removes hydrogen