alcohol,phenols,ethers
Experiment #8 – properties of Alcohols and Phenols
Introduction
As has been mentioned before, over 20 million organic compounds have been identified. If each substance had to be studied as an entity completely separate from all the other substances, the study of organic chemistry as a whole would be impossible; that is to say, even more impossible than you currently believe it to be. Fortunately, the subject can be organized and it is often organized around the concept of the functional group. A functional group is an atom or group of atoms, bonded together in a certain way, that, as part of a molecule, will impart certain physical and chemical characteristics to the molecule as a whole. It is the case that the rest of the molecule can modify the characteristics of the functional group. It is also the case that if the rest of the molecule is an alkyl group the modifications may be modest. On the other hand, other functional groups in the molecule, especially if they are close by, are more likely to profoundly modify the characteristics of the functional group in question.
The functional group we are considering in this experiment is the hydroxy (or hydroxyl) functional group, -OH. This group shows up in a number of guises in organic compounds. Some of the common ones are shown in the table below.
Functional Group Structure
Compound Generic Name
Comments
alcohol
In an alcohol, the -OH is attached to a tetrahedral carbon atom. Very weekly acidic. enol
Two functional groups attached to the same carbon. It’s an alkene and an alcohol. Usually unstable. phenol
-OH directly bonded to an aromatic ring. Weekly acidic. hemiacetal
Two functional groups attached to the same carbon. Formed from reaction between an alcohol and an aldehyde or ketone. carboxylic acid
Two functional groups attached to the same carbon. Moderately acidic.
C OH
C
C
OH
OH
C O C OH
C OH
O
Experiment #8
Introduction
As has been mentioned before, over 20 million organic compounds have been identified. If each substance had to be studied as an entity completely separate from all the other substances, the study of organic chemistry as a whole would be impossible; that is to say, even more impossible than you currently believe it to be. Fortunately, the subject can be organized and it is often organized around the concept of the functional group. A functional group is an atom or group of atoms, bonded together in a certain way, that, as part of a molecule, will impart certain physical and chemical characteristics to the molecule as a whole. It is the case that the rest of the molecule can modify the characteristics of the functional group. It is also the case that if the rest of the molecule is an alkyl group the modifications may be modest. On the other hand, other functional groups in the molecule, especially if they are close by, are more likely to profoundly modify the characteristics of the functional group in question.
The functional group we are considering in this experiment is the hydroxy (or hydroxyl) functional group, -OH. This group shows up in a number of guises in organic compounds. Some of the common ones are shown in the table below.
Functional Group Structure
Compound Generic Name
Comments
alcohol
In an alcohol, the -OH is attached to a tetrahedral carbon atom. Very weekly acidic. enol
Two functional groups attached to the same carbon. It’s an alkene and an alcohol. Usually unstable. phenol
-OH directly bonded to an aromatic ring. Weekly acidic. hemiacetal
Two functional groups attached to the same carbon. Formed from reaction between an alcohol and an aldehyde or ketone. carboxylic acid
Two functional groups attached to the same carbon. Moderately acidic.
C OH
C
C
OH
OH
C O C OH
C OH
O
Experiment #8