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Topic: help answering my questions please!!!  (Read 6494 times)

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amydancery

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help answering my questions please!!!
« on: September 18, 2004, 04:54:21 AM »
questions:
in each case, give the structural formula of the organic product and describe what you would see during the reaction.
a. warm acidified potassium dichromate with vanilla
b. ethanoyl chloride with vanilla
c. sodium hydroxide solution with vanilla
d. 2,4-dinitrophenylhydrazine with vanilla

vanilla consists of an aldehyde group and a phenol group~~
becoz i haven't learn organic chem, so i don't know how to do this, please help me~~~ ??? :bop:

Offline Donaldson Tan

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Re:help answering my questions please!!!
« Reply #1 on: September 18, 2004, 04:13:02 PM »
Quote
vanilla consists of an aldehyde group and a phenol group~~
I'm not sure about the structure of vanilla, but i'll base my reply on your information.

Quote
a. warm acidified potassium dichromate with vanilla
this should oxidise the aldehyde group to a carboxylic acid.

Quote
b. ethanoyl chloride with vanilla
this will cause the phenol group to undergo esterification with ethanoyl chloride.

Quote
c. sodium hydroxide solution with vanilla
sodium phenoxide salt will be formed.

Quote
d. 2,4-dinitrophenylhydrazine with vanilla
I'm not too sure about the chemistry of this reagent.
"Say you're in a [chemical] plant and there's a snake on the floor. What are you going to do? Call a consultant? Get a meeting together to talk about which color is the snake? Employees should do one thing: walk over there and you step on the friggin� snake." - Jean-Pierre Garnier, CEO of Glaxosmithkline, June 2006

Offline movies

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Re:help answering my questions please!!!
« Reply #2 on: September 20, 2004, 12:23:43 PM »
I'm not too sure about the chemistry of this reagent.

This will make the 2,4 DNP derivative of an aldehyde in the compound.

celan

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Re:help answering my questions please!!!
« Reply #3 on: September 20, 2004, 10:47:07 PM »
Vanilin reacts with 2,4-dinitrophenylhydrazine give vanilin 2,4-dinitrophenylhyrazone.

Offline AWK

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Re:help answering my questions please!!!
« Reply #4 on: September 21, 2004, 02:49:41 AM »

Quote:
c. sodium hydroxide solution with vanilla
 
sodium phenoxide salt will be formed.


At the presence oF NAOH excess the Cannizzoro reaction should be also taken into account
AWK

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Re:help answering my questions please!!!
« Reply #5 on: September 21, 2004, 12:36:33 PM »
The Cannizzaro reaction should be much slower than the phenol deprotonation though.  I would think that the Cannizzaro reaction on the deprotonated compound would be slower still since the phenoxide can donate into the aldehyde (making it less prone to attack by OH-).  I suppose it still might happen though.

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