Flashcards in Organic Chemistry- Alcohols Deck (83)
What are the most common chemicals you'll find in organic chemistry?
Alcohols have the general formula of what?
What functional group are alcohols in?
-OH referred to as a hydroxyl group
How are alcohols named in the IUPAC system?
Replacing the -e ending of the root alkane with the ending -ol
What happens if alcohol is the highest priority functional group when bonding?
The carbon atom attached to it receives the lowest possible number
What happens if alcohol is not the highest priority function group when bonding?
It is named as a substituent, with the prefix hydroxy-
What is the common naming practice for alcohols?
To name the alkyl group as a derivative followed by alcohol
Hydroxyl groups can be attached to what? What is it called?
The hydroxyl hydrogens of phenols are particularly, what? why?
Acidic due to resonance within the phenol ring.
What should you do if benzene rings contain 2 substituents?
Their relative positions must be indicated.
What must be added to the name, if two substituents are on adjacent carbons on a benzene ring?
Ortho- or simply O-
What must be added to the name, if two substituents are separated by a carbon on a benzene ring?
meta- or m-
What must be added to the name, if two substituents are on opposite sides of a benzene ring?
Para- or p-
What is one of the prominent properties of alcohols? Which results in what?
They are capable of intermolecular hydrogen bonding, which results in significantly higher melting and boiling points than those analogous hydrocarbons
What should you lookf for in an alcohol molecule to know if there is greater hydrogen bonding? What else can you look for?
Molecules with more hydroxyl groups show greater degrees of hydrogen bonding.
Boiling point increases significantly with additional hydroxyl groups which permit more hydrogen bonding.
When does hydrogen bonding occur?
Hydrogen bonding occurs when hydrogen atoms are attached to highly electronegative atoms like nitrogen, oxygen, or fluorine
Hydrogen bonding is the result of what?
The extreme polarity of these bonds.
In the case of a hydroxyl group, what happens during hydrogen bonding?
The electronegative oxygen atom pulls electron density away from the less electronegative hydrgen atom. This generates a slightly positive charge on the hydrogen and slightly negative charge on the oxygen. Then, the partially positive hydrogen of one molecule electrostatically attracts the partially negative oxygen of another molecule, genrating a noncovalent bonding force known as a hydrogen bond.
Hydroxyl hydrogens are weakly what?
What can alcohol dissociate to?
Protons and alkoxide ions in the same way that water dissociates into protons and hydroxide ions
What are the dissociations of 7 hydroxyl-containing compounds?
H20 HO + H+
CH3OH CH3O + H+
C2H5OH C2H5O- + H+
I-PrOH i-PrO + H+
t-BuOH t-BuO- H+
CF3CH2OH CF3CH2O + H+
PhOH PhO- + H+
What are more acidic than other alcohols? Why?
Hydroxyl hydrogens of phenols. This is due to the armoatic nature of he ring which allows for the resonance stabilization of the negative charge on oxygen, stabilizing the anion.
Like other alcohols, What do phenols form?
Intermolecular hydrogen bonds and have relatively high melting and boiling points.
Phenol is slightly soluable in what? Why?
Water, owing to hydrogen bonding, as are some of its derivatives
Phenols can form what, that other alcohols can't? Why?
Salts with inorganic bases such as NaOH
Because phenols are more acidic then other alcohols
The presence of other substituents on the ring has significant effect on what?
The acidity, boiling points, and melting points of phenols.
What increases and decreases acidity?
Electron-withdrawing substituents increase acidity
Electron-donating groups decrease
The presence of more alkyl groups in non aromatic alcohol produces what? Why?
Less acidic molecules because alkyl groups donate electron density, they destabilize a negative charge.
Alkyl groups help do what? Explaining why what happens?
Stabilize positive charges, explaining why more substitued carbocations have higher stability than less