Concept Summary

Description and Properties

Reactions of Alcohols

Alcohols    have    the general form    ROH and are named   with    the suffix  – ol.   If  they    are not the highest

priority,   they    are given   the prefix  hydroxy–.

Phenols are benzene rings   with    hydroxyl    groups. They    are named   for the relative    positions   of  the

hydroxyl    groups: ortho–  (adjacent   carbons),   meta–   (separated  by  one carbon),    or  para–   (on

opposite    sides   of  the ring).

Alcohols    can hydrogen    bond,   raising their   boiling and melting points  relative    to  corresponding

alkanes.    Hydrogen    bonding also    increases   the solubility  of  alcohols.

Phenols are more    acidic  than    other   alcohols    because the aromatic    ring    can delocalize  the charge

of  the conjugate   base.

Electron-donating   groups  like    alkyl   groups  decrease    acidity because they    destabilize negative

charges.    Electron-withdrawing    groups, such    as  electronegative atoms   and aromatic    rings,

increase    acidity because they    stabilize   negative    charges.

Primary alcohols    can be  oxidized    to  aldehydes   only    by  pyridinium  chlorochromate  (PCC);  they

will    be  oxidized    all the way to  carboxylic  acids   by  any stronger    oxidizing   agents.

Secondary   alcohols    can be  oxidized    to  ketones by  any common  oxidizing   agent.

Alcohols    can be  converted   to  mesylates   or  tosylates   to  make    them    better  leaving groups  for

nucleophilic    substitution    reactions.

Mesylates   contain the functional  group   –SO 3 CH 3 ,    which   is  derived from    methanesulfonic acid.

Tosylates   contain the functional  group   –SO 3 C 6 H 4 CH 3 ,    which   is  derived from    toluenesulfonic

acid.

Aldehydes   or  ketones can be  protected   by  converting  them    into    acetals or  ketals.

Two equivalents of  alcohol or  a   dialcohol   are reacted with    the carbonyl    to  form    an  acetal  (a