CAP 13 Flashcards
Alchol
- OH group
- C-O bond is polarized due to the electronegative forces
- liquid
- Short chain alcohols are soluble in water ( long chain= insoluble )
Widely used as disinfectants ( reacts with proteins and denatures them) , paint thinners and recreational purposes
Naming alcohols
The alkane name is changed to include the -ol suffix
ex. methane= methanol
If there are three or more carbon atoms we specify the position of the substituent
Thiols
Also known as mercaptans
- SH sulfhydryl
- Volatile ( sulfur is a poor hydrogen bond acceptor)
- Disagreeable odor
Naming thiols
Named by adding thiol to the alkane name of the longest carbon chain and numbering the carbon chai from the end nearer the -SH group
ex. Methane, Metanethiol
Ethers
Similar to alcohols, but they have an oxygen atom bridging two alkyl or aromatic groups
- highly volatile
- poorly soluble in water
- important anesthetics
Naming ethers
- Practical: name the two substituents and add ether at the end
ex. methyl ethyl ether, diethyl ether, etc. - IUPAC: the shorter chain is named as an alkoxy group, the longer as the corresponding alkane
ex. methoxyethane, ethoxyethane, etc.
Alcohol reactivity
Due to:
- The polarized C-O bond
- The presence of lone pairs on the oxygen, making the alcohol a nucleophile
Alcohols classes
primary: carbon linked only to one carbon atom
secondary: carbon linked to two carbon atom
tertiary: carbon linked to three atoms
Alcohol oxidation
We can oxidize primary and secondary alcohols
primary oxidized: aldehydes
secondary oxidized: ketones
Esterification of alcohols
Reaction of alcohols with acids to form esters
The acids can be organic or inorganic
Esters are very important in biology
Elimination
Alcohols can also eliminate water ( to produce alkenes)
In order for this to happen, you need an hydrogen linked to the carbon atom next to the one that bears the -OH group
The idea is that by removing one hydrogen and on hydroxyl, we get the formation of the double bond that characterizes the alkenes
(In an acidic environment)
Acid/base equilibria
Alcohols are extremely weak acids
Their acidity in general depends on what they have attached to the -OH
Thiols oxidation
They can be oxidized to a series of different compounds which differ in the number of oxygen atoms that we find attached to the sulfur
Cysteine
Most importan thiol
Two molecules of this amino acid react together and get oxidized to form a disulphide bond (so the two sulphurs are linked together covalently).
Carbonyl functional group
A carbon atom (hybridized sp2) double bonded to an oxygen atom
The geometry is planar because of the hybridisation ( 120 degrees)
The carbonyl group is characterised by a dipole (negative charge on the oxygen and positive charge on the carbon) because of the electronegativity difference.
