SELAMAT DATANG


Kamis, 07 Juni 2012

PROBLEM
1. why amide does'nt reactive?
2. Why can not hydrolyze amide without a catalyst?
  
  answer :  
  1. Amide is a compound that is not reactive, since the protein consists of amino acids linked by amide bonds. Amide does not react with halide ions, ionkarboksilat, alcohol, or water because in each case, the incoming nucleophile is basalemah of the amide group to go. Amide can react with water and alcohol if the reaction mixture was heated dalamsuasana asam.Teori molecular orbitals may explain why the amide is not reactive. Amide resonance memilikikontributor important where one partner shares with karbonkarbonil nitrogen, which contains a lone pair orbital overlap of the vacant orbital overlap guguskarbonil.Keadaan lower-energy one partner is not a base or nucleophilic, and raises the energy of the orbital of the carbonyl group, resulting in less reactive terhadapnukleofil. Amide NH 2 groups can be dehydrated to a nitrile. Reagendehidrasi generally used for this purpose is P2O5, POCl3, and SOCl3.
  2. In the reaction without catalyst, amidatidak protonated. Therefore, the water, a very poor nucleophile, should be neutral menyerangamida far more susceptible to nucleophilic than serangandari amidaterprotonasi. In addition, the group of the tetrahedral intermediate is not protonated in the reaction without a catalyst. Therefore, the-OH group is away from the tetrahedral intermediate, because  -OH is a weak base of the -NH2 amide reform. A amidabereaksi with alcohol under acidic conditions for the same reason will bereaksidengan water under acidic conditions.


                                                                                                   
                                                       I’m sorry if there are mistakes

3 komentar:

  1. guys.....
    thats right???
    please your coment...

    BalasHapus
  2. Komentar ini telah dihapus oleh pengarang.

    BalasHapus
  3. as we know in basic chemistry the function of catalyst.

    Catalyst is a substance that accelerates the reaction rate of chemical reaction at a certain temperature, without changes or abandoned by the reaction itself (see also catalysis). A catalyst role in the reaction but not as a reactant or product.

    The catalyst allows the reaction to go faster or allow the reaction at lower temperatures due to the changes that triggered the reagent. Catalyst provides a path of options with a lower activation energy. The catalyst reduces the energy required for the course of the reaction.
    so if there is no catalyst, the reaction may take place, but more slowly or may not occur because there's no a trigger.

    When the amide is hydrolyzed in acidic conditions, acid proton of the carbonyl oxygen, increase the susceptibility of the carbonyl carbon to nucleophilic attack.
    And then will occur as you describe above..

    --i'm sorry if there are mistakes--

    BalasHapus