Lecture 9 Monday 2/6/17

ALCOHOLS, PHENOLS, & ETHERS A __________________ is the –OH functional group. An ________________ has an –OH group attached to an aliphatic carbon atom. General formula: R-OH A ________ has an –OH group on a benzene ring. An ether has the functional group: Ether general formula:

ALCOHOL EXAMPLES

NAMING ALCOHOLS OH | CH3—CH2—CH2—CH—CH2—CH3 Step 1: Name the longest chain to which the –OH group is attached. Use the hydrocarbon name of the chain, drop the final –e, and replace it with –ol. Step 2: Number the longest chain to give the lowest number to the carbon with the attached –OH. Step 3: Locate the –OH position. Example: OH | CH3—CH2—CH2—CH—CH2—CH3

NAMING ALCOHOLS (continued) Step 4: Locate and name any other groups attached to the longest chain. Step 5: Combine the name and location of other groups, the location of the –OH, and the longest chain into the final name. Example: Note: Alcohols containing two –OH groups are diols, three –OH groups are triols. The IUPAC names for these compounds have endings of –diol and –triol rather than –ol. CH3—CH2—CH—CH—CH—CH3 OH | CH3

NAMING PHENOLS Substituted phenols are usually named as derivatives of the parent compound phenol. Examples:

CLASSIFICATION OF ALCOHOLS

PHYSICAL PROPERTIES OF ALCOHOLS The –OH group is polar and capable of hydrogen bonding. This makes low molecular weight alcohols highly soluble in water. Hydrogen bonding in a water-methanol solution:

PHYSICAL PROPERTIES OF ALCOHOLS (continued) Larger alkanes have greater hydrophobic regions and are less soluble or insoluble in water. Water interacts only with the –OH group of 1-heptanol:

PHYSICAL PROPERTIES OF ALCOHOLS (continued)

PHYSICAL PROPERTIES OF ALCOHOLS (continued) The –OH group can hydrogen bond between alcohol molecules leading to relatively high boiling points. Hydrogen bonding in pure ethanol:

PHYSICAL PROPERTIES OF ALCOHOLS (continued)

ALCOHOL REACTIONS The removal of water ______________ from an alcohol at 180ºC is an _________________ that produces an alkene.

ALCOHOL DEHYDRATION TO ALKENE EXAMPLES

DEHYDRATION OF AN ALCOHOL Protonation of alcohol Formation of carbocation and water Formation of double bond and regeneration of catalyst

ALCOHOL REACTIONS (continued) Under slightly different conditions (140ºC), a dehydration reaction can occur between two alcohol molecules to produce an

ALCOHOL DEHYDRATION TO ETHER EXAMPLE

ALCOHOL REACTIONS (continued)