November 28, 2021, 06:54:14 AM
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Topic: NaOH + diethylamine hydrochloride + sodium lauryl sulfate + m-toluoyl chloride  (Read 768 times)

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Offline xshadow

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Hi

I have a doubt about this reaction

First I have to add 35ml NaOH(aq) 4M  with 25 mmol diethylamine hydrochloride .

Than I have to add 0.1g of sodium lauryl sulfate
After this when I add 30mmol of m- toluoyl chloride (liquid) the reaction will occur



Now I have two question:

1)what is the role of sodium lauryl sulfate?
2) when I add m-toluoyl chloride ...do we have a two phase system? (One orgamic witj m-toluoyl chloride and one aqueous with NaOH and water?

And  in which phase will the amine stay when the reaction occurs? In the aqueos phase(Reaction  at the interface?) Or witm-toluyl

Bacause...amine should be soluble in water

THANKs





Offline Babcock_Hall

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What do you know about the properties of sodium dodecyl sulfate?

Offline xshadow

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What do you know about the properties of sodium dodecyl sulfate?

Hi

I know that is a surfactant
A surfactant  (apolar head and apolar tail)should increase the solubility of some (organic) compounds on water


But is it used to increase the solubility of the amine (or is already soluble enough in water) or the solubility of m-toluoyl chloride in water (where we put the amine ,the other reactive specie in this reaction)

Because without surfactant I don't know  if m-toluoyl  chloride con mix with water(+NaOH +NHEt2 ) in order to react...or this type of reactions happens at the surface of two phase (one organic and one aqeous)?



Thanks

Offline AWK

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Are you going to run the reaction without stirring the solution? What happens to the surfactant solution under the above conditions.
AWK

Offline xshadow

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Are you going to run the reaction without stirring the solution? What happens to the surfactant solution under the above conditions.
Sorry, yes I also have  to put a magnetic stir bar in the solution


Perhaps... an emulsion?

When the mixture is stirred the surfactant generate an emulsion??
So I can't see two distinct separate phase but they are """mixed""" ...so that the insoluble (I think)  m-toluoyl chloride can interact with the NaOH-Et2NH solution

Is it correct??
thanks!

Offline AWK

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That's what it's all about. The large contact area of ​​immiscible reactants shortens the Schotten-Baumann reaction time.
AWK

Offline xshadow

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That's what it's all about. The large contact area of ​​immiscible reactants shortens the Schotten-Baumann reaction time.

But at this point I have one last doubt

In order to do this reaction I have use  a three neck round-bottom flask ( in the middle neck I put  a bubble ccondenser in a one-side neck a dropping funnel and in the last one a plug)

1) I add in the empty three neck  round flask  30 mmole of m-toluoyl chloride
2)After this I add  in the dropping funnel a  35ml NaOH 4M solution with also 25mmole of Diethylamine hydrochloride + 0,1g of sodium lauryl sulfate
3) a open the dropping funnel and the aqueous solution fall in the flask drop by drop.


Now my question is:

The droplets of the aquous solutuion contains:
NaOH  so OH-
NHEt2

When these meet the  m-toluoyl chloride the amine can react with this...but from org chem1 I also know that OH- can react with acyl  halide in order to give a carboxylic acid...so  here I also have the formation of some ""acid  benzoic"" (then deprotonated by NaOH,very concentrated)

thanks

Offline AWK

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In your procedure you use the simplest conditions for the Schotten-Baumann reaction. Hydrolysis of some of the acid chloride is inevitable.
Therefore, ice cooling of the reaction mixture is also used. With the more valuable acid chlorides, disgustingly smelling pyridine is used instead of NaOH.
AWK

Offline xshadow

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In your procedure you use the simplest conditions for the Schotten-Baumann reaction. Hydrolysis of some of the acid chloride is inevitable.
Therefore, ice cooling of the reaction mixture is also used. With the more valuable acid chlorides, disgustingly smelling pyridine is used instead of NaOH.

thanks!!

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