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Problems that could be encountered when reacting benzoyl chloride and ammonia? watch

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    b) Acyl chlorides can also be used to prepare other derivatives of caboxylic acids, such as amides.

    (i) What acyl chloride and what reagent would be needed to prepare benzamide

    Acyl chloride - benzoyl chloride
    Reagent - ammonia

    (ii) What type of reaction is this?
    Addition-elimination reaction

    Are these correct?


    (iii) What problem mght be encountered when carrying out such preparations in the laboratory? Explain the chemical origin of the problem and sate what precaution could be taken to minimise it.

    Problem ...... (1 mark)
    Origin ..... (1 mark)
    Precaution .... (1 mark)

    I was thinking it would be when the benzoyl chloride reacts with the water in the surface of your eyes, but I've already answered that when asked what disadvantages does using acyl chlorides have in preparation of esters compared to carboxylic acids.

    What should I answer here?

    Thanks for your help.
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    Acid chlorides are generally lachrymators (they attack the mucous membranes of your eyes, nose, throat), they are also corrosive and burn the skin.

    Adding an acid chloride and an amine together is generally an extremely vigorous reaction so needs very careful control (slow addition and cooling).

    MP
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    (Original post by MaturePharm)
    Acid chlorides are generally lachrymators (they attack the mucous membranes of your eyes, nose, throat), they are also corrosive and burn the skin.

    Adding an acid chloride and an amine together is generally an extremely vigorous reaction so needs very careful control (slow addition and cooling).

    MP
    What makes chloride and amine react vigorously together?

    Also, what is it about the vigorous reaction that is a problem? Does it explode? Does it produce a large amount of steam?
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    (Original post by Alpha-Omega)
    What makes chloride and amine react vigorously together?

    Also, what is it about the vigorous reaction that is a problem? Does it explode? Does it produce a large amount of steam?
    Acid chlorides are extremely electrophilic. Amines are very good nucleophiles. Hence they love getting together.

    No, they don't 'explode' (explosion has a certain definition), but they react pretty much instantly and generate a lot of heat. Hence you would need to do the reaction in an inert solvent, preferably one with a reasonably high boiling point to prevent it boiling. Also worth applying some external cooling and adding one of the reagents via a dropping funnel to control the exotherm.

    And no, there would be no steam produced at all. Unless you were trying to do the reaction in water which would be rather dumb...

    MP
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    (Original post by MaturePharm)
    Acid chlorides are extremely electrophilic. Amines are very good nucleophiles. Hence they love getting together.

    No, they don't 'explode' (explosion has a certain definition), but they react pretty much instantly and generate a lot of heat. Hence you would need to do the reaction in an inert solvent, preferably one with a reasonably high boiling point to prevent it boiling. Also worth applying some external cooling and adding one of the reagents via a dropping funnel to control the exotherm.

    And no, there would be no steam produced at all. Unless you were trying to do the reaction in water which would be rather dumb...

    MP
    Thanks, this is what I was looking for!
 
 
 

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