Chem ch 15 Flashcards
no hydrogen bonding (the twins)
aldehydes and ketones
formaldehyde
methanal - CH2O
acetaldehyde
ethanal - CH3-C (=O attached at the top) -H
the H will always be shown in an..
aldehyde
no hydrogens on
ketones
benzaldehyde
just benzene w/ CHO attached at top
when naming an aldehyde attached to cyclic, name it…(with the cyclic it’s too many carbs)
cyclohexane carbaldehyde - the cyclo w/ carbaldehyde at the end.
naming straight chain aldehydes (alden is al)
don’t number the aldehyde - it’s just 3-methylhexanal
does aldehyde or OH group have priority?
aldehyde
ketones end in (literally the end of ketone)
one, ie 3-pentanone
don’t do methyl & ethyl (common names) for ketones when..
the chains get longer. Just use IUPAC - ie. butanone.
diphenyl ketone
a ketone w/ 2 phenyls - one on each side (phenyl is benzene minus one H)
when naming, if you have a ketone and a double bond…
split the name in half. ie - 3-penten-2-one. (the double bond on 3 goes first)
ending of a ketone (key to one heart)
one
aldehyde naming ends in (alden is al)
al
what has the highest boiling point? butane, butanol, or butanal?
butanal bc it has dipole dipole and H bonding
C and O is what type of bonding?
dipole dipole
super solvent
acetone
aldehydes oxidized to…
carboxylic acid
ketones oxidized to..(no oxy in the keys)
NR - can’t be oxidized
when oxidizing aldehyde
just attach the O to the H group - so it’s - OH.
when oxidizing, if you already have a double bond O, attach the O
to the free H
tollen test or tollen’s reagent (pay the toll w/ silver - then cho)
used to distinguish between aldehyde and ketone. if silver, it’s an aldehyde
benedict’s test
blue copper turns brick red
aldehyde w/ benedict test turns what color?
red
benedict test cannot be used to..
distinguish between aldheyde and ketone
reagent and product w/ tollen’s test is…
reagent is Ag+, product is Ag
Reagent and product w/ Benedict’s test (old Ben likes copper)
reagent is CU2+, and product is CU+
primary alcohol reduced to..
aldehyde
secondary alcohol reduced to
ketone
reducing agent brings what to a reaction?
H+ and H- (this is called hyride ion)
in a reduction reaction, you are literally just…
adding 2 Hs. One to the O group, and one to the free arm
pyruvic acid formula
CH3 - C (=O attached on top of the C)- COOH
NAD+ is an___agent (carbonyl group)
oxidizing
NADH is an____agent (carbonyl group)
reducing
aldehyde + alcohol = ?
hemiacetal
ketone + alcohol = ?
hemiketal
hemiacetals will always have this exact structure
OH, H, C (central carbon), OC, C
hemiketals will always have this structure
C (central carbon), OC, OH, C, C
reaction of acetalaldehyde
you are literally just moving the H to the top O and making it a single bond, and moving the O-CH3-CH3 (or whatever is in the chain) to the side of the central C
acetal vs. hemiacetal
hemiacetal has an OH, acetal just has an OR group
alkoxy group
any C attached to an O
carbonyl group
just C=O - that’s it
when naming aldehydes, remember to…
count the C that is attached to the double O and H
when naming ketones using common name
Don’t count the C with attached double O - just start on either side
when counting Cs on ketones with O in the middle
DO NOT count the O in the middle as a C
when drawing aldehydes…
remember to add an extra line with the H on the end
what ketones and aldehydes are water soluble?
simple ones
ketones are good solvents for..
many polar and nonpolar solutes
how to tell if aldehyde or ketone is soluble
if they have less than 4 carbons much more soluble. fewer than 5 or 6 are soluble.
aldehydes and ketones have lower BPs that alcohol because…
they only have dipole-dipole forces that are weak, easy to break. alcohols have hydrogen bonding.
C-C=O-H with a mild oxidizing agent
another O is added to the free H - so it’s C-C=O-OH
what Tollen’s test does
since ketones can’t be oxidized (the don’t have anywhere to attach the extra O) you’re oxidizing to tell if it’s an aldehyde or ketone
what benedict’s test does
this is also an oxidizing agent, and it will turn red if aldehyde is present. BUT, it also turns red if there is a ketone with an OH next to the O, so it’s not totally accurate. You need a negative Tollen’s and positive Benedict to tell if it’s a ketone
if you’re reducing something like a benzaldehyde…
and you don’t have anywhere to the put the extra H, just attach it to a separate line right next to the OH group at the top
hemiacetals
an alcohol plus an aldehyde
hemiketals
an alcohol plus a ketone
acetal
2 ether-like OR groups (O-CH2CH3) on same carbon that was an aldehyde
ketal
2 ether-like (O-CH2CH3) groups bonded to what was a ketone
how to recognize an acetal
2 OR groups (CH3O) and a H, it’s acetal
how to recognize a ketal
2 OR groups (CH3O) and 2 R groups (Carbons) it’s a ketal
how to tell if it’s a hemiacetal or hemiketal
look for the C that has 2 single bonds to the O. if the 2 remaining bonds are C, it’s a ketal. If one is C and the other is H, it’s acetal.
acetaldehyde (ace the hyde w/ narc)
sweet smelling but narcotic
benzaldehyde (cherry benz)
sweet smelling cherry almond
what can be reduced to alcohol?
aldehydes and ketones
acetal
has 2 ether (either C or C) like groups bonded to a carbon - for example - OR-OR-C-C (OR is replacing the OH in hemiacetal)
acetal has same formula as hemiacetal but…
the OH will be replaced by an OR group. same with ketals and hemiketals
EASY way to identify hemiacetal or acetal
if the central carbon (the one attached to 2 Os) has 1 alkoxy group (an O with CH or something attached) it’s a hemiacetal. If the C has O attached with 2 alkoxy groups, it’s an acetal.
