Write the chemical reactions for the different methods used for the reduction of aldehydes and ketones.
Answers
Answered by
1
REDUCTION OF ALDEHYDES AND KETONES
This page looks at the reduction of aldehydes and ketones by two similar reducing agents - lithium tetrahydridoaluminate(III) (also known as lithium aluminium hydride) and sodium tetrahydridoborate(III) (sodium borohydride).
Background to the reactions
The reducing agents
Despite the fearsome names, the structures of the two reducing agents are very simple. In each case, there are four hydrogens ("tetrahydido") around either aluminium or boron in a negative ion (shown by the "ate" ending).
The "(III)" shows the oxidation state of the aluminium or boron, and is often left out because these elements only ever show the +3 oxidation state in their compounds. To make the names shorter, that's what I shall do for the rest of this page.
REDUCTION OF ALDEHYDES AND KETONES
This page looks at the reduction of aldehydes and ketones by two similar reducing agents - lithium tetrahydridoaluminate(III) (also known as lithium aluminium hydride) and sodium tetrahydridoborate(III) (sodium borohydride).
Background to the reactions
The reducing agents
Despite the fearsome names, the structures of the two reducing agents are very simple. In each case, there are four hydrogens ("tetrahydido") around either aluminium or boron in a negative ion (shown by the "ate" ending).
The "(III)" shows the oxidation state of the aluminium or boron, and is often left out because these elements only ever show the +3 oxidation state in their compounds. To make the names shorter, that's what I shall do for the rest of this page.
Note: It isn't important as far as the current page is concerned, but if you want to understand more about oxidation states (oxidation numbers), you will find them explained if you follow this link.
Use the BACK button on your browser to return to this page.
The formulae of the two compounds are LiAlH4 and NaBH4.
Their structures are:

In each of the negative ions, one of the bonds is a co-ordinate covalent (dative covalent) bond using the lone pair on a hydride ion (H-) to form a bond with an empty orbital on the aluminium or boron.
Note: Follow this link if you aren't happy about co-ordinate covalent (dative covalent) bonding.
Use the BACK button on your browser to return to this page.
The overall reactions
The reduction of an aldehyde
You get exactly
This page looks at the reduction of aldehydes and ketones by two similar reducing agents - lithium tetrahydridoaluminate(III) (also known as lithium aluminium hydride) and sodium tetrahydridoborate(III) (sodium borohydride).
Background to the reactions
The reducing agents
Despite the fearsome names, the structures of the two reducing agents are very simple. In each case, there are four hydrogens ("tetrahydido") around either aluminium or boron in a negative ion (shown by the "ate" ending).
The "(III)" shows the oxidation state of the aluminium or boron, and is often left out because these elements only ever show the +3 oxidation state in their compounds. To make the names shorter, that's what I shall do for the rest of this page.
REDUCTION OF ALDEHYDES AND KETONES
This page looks at the reduction of aldehydes and ketones by two similar reducing agents - lithium tetrahydridoaluminate(III) (also known as lithium aluminium hydride) and sodium tetrahydridoborate(III) (sodium borohydride).
Background to the reactions
The reducing agents
Despite the fearsome names, the structures of the two reducing agents are very simple. In each case, there are four hydrogens ("tetrahydido") around either aluminium or boron in a negative ion (shown by the "ate" ending).
The "(III)" shows the oxidation state of the aluminium or boron, and is often left out because these elements only ever show the +3 oxidation state in their compounds. To make the names shorter, that's what I shall do for the rest of this page.
Note: It isn't important as far as the current page is concerned, but if you want to understand more about oxidation states (oxidation numbers), you will find them explained if you follow this link.
Use the BACK button on your browser to return to this page.
The formulae of the two compounds are LiAlH4 and NaBH4.
Their structures are:

In each of the negative ions, one of the bonds is a co-ordinate covalent (dative covalent) bond using the lone pair on a hydride ion (H-) to form a bond with an empty orbital on the aluminium or boron.
Note: Follow this link if you aren't happy about co-ordinate covalent (dative covalent) bonding.
Use the BACK button on your browser to return to this page.
The overall reactions
The reduction of an aldehyde
You get exactly
Similar questions