OCR A Chemistry F324 Rings, Polymers and Analysis Thu 26 Jan 2012

Why is ethanol used as a solvent for the nucleophillic substitution of a halogenoalkane for the Amine group? I know the NH3 is in excess to prevent further substitution. But whats the purpose of Ethanol?

all i know is the nh3 is dissolved in the ethanol sorry :smile:

Reply 661

arvin_infinity

3

Original post by atman7

Why is ethanol used as a solvent for the nucleophillic substitution of a halogenoalkane for the Amine group? I know the NH3 is in excess to prevent further substitution. But whats the purpose of Ethanol?

Interested to know that as well..quote me if you found out :smile:

Reply 662

atman7

8

Original post by faz_341

all i know is the nh3 is dissolved in the ethanol sorry :smile:

Original post by arvin_infinity

Interested to know that as well..quote me if you found out :smile:

Just found out after a quick google Ethanol is the alternative solvent used because if water is used it'll lead to hydrolysis occurring.

thats the source http://books.google.co.uk/books?id=25qJbzc1wMEC&pg=PA141&lpg=PA141&dq=why+ethanol+used+as+solvent+in+nucleophilic+substitution+of+halogenoalkane+for+amine&source=bl&ots=UXuWyFigAS&sig=YGweDI7-BbUPa1IxaU0APvR_Uvk&hl=en&sa=X&ei=VKYgT-LQCsnq8QPYx43gBw&ved=0CF4Q6AEwCQ#v=onepage&q=why%20ethanol%20used%20as%20solvent%20in%20nucleophilic%20substitution%20of%20halogenoalkane%20for%20amine&f=false

Reply 663

079

whos doing all nighter? I have no choice I wont be sleeping even if I try!

Reply 664

Phenylethylamine_

I'm doing some questions at the moment...

Reply 665

atman7

8

Original post by 079

whos doing all nighter? I have no choice I wont be sleeping even if I try!

My sleeping patterns are messed up anyways and I only woke up few hours ago so I'll be doing the same as you :smile:

Reply 666

S_Azizi

Original post by atman7

My sleeping patterns are messed up anyways and I only woke up few hours ago so I'll be doing the same as you :smile:

Meh, in the same boat...lol

Reply 667

Saliency

17

Just woke up guys. Revision time :biggrin:

Reply 668

Kisskoli

Original post by atman7

Why is ethanol used as a solvent for the nucleophillic substitution of a halogenoalkane for the Amine group? I know the NH3 is in excess to prevent further substitution. But whats the purpose of Ethanol?

renewable?

Reply 669

atman7

8

Original post by Kisskoli

renewable?

Its actually cause using Water will cause hydroylsis to happen and the ethanol is just an alternative to use.

Reply 670

arvin_infinity

3

Original post by Kisskoli

renewable?

Definition of adsorption ?! the one is book is so complicated..wondered if someone explain it or has a better definition !!

+rep

Reply 671

Kisskoli

Original post by arvin_infinity

Definition of adsorption ?! the one is book is so complicated..wondered if someone explain it or has a better definition !!

+rep

when something in the solid/gas attaches to a solid/ film

Reply 672

LifeIsGood

12

Original post by arvin_infinity

Definition of adsorption ?! the one is book is so complicated..wondered if someone explain it or has a better definition !!

+rep

When the liquid or solid is sticking towards the solid surface

I really don't want NMR to come up :frown:

Reply 673

Stevo F

18

Morning all :smile:

what can be the benefits of using a catalyst which compounds adsorb to?

Reply 674

LifeIsGood

12

Original post by Stevo F

Morning all :smile:

what can be the benefits of using a catalyst which compounds adsorb to?

Isn't it because it's not used up and can be regenerated? That's the only property I can think of that is useful for them in this context

Reply 675

Hullabaloo2803

Original post by Oromis263

No mistake, I was just sharing a little something that I've found has stuck in my head :smile:

Haha oh cool :smile:

well all the best for the exam anyway! :smile:

Reply 676

Hullabaloo2803

Hello all

I was wondering if someone could help me, im just a bit confused on chromotography, is it:
Tlc- seperates by Adsorption and Gc- seperates by relative solubility?

Reply 677

Stevo F

18

Original post by LifeIsGood

Isn't it because it's not used up and can be regenerated? That's the only property I can think of that is useful for them in this context

no that's a property of any catalyst, that its not used up, a bonus with "fixed" catalysts that compounds adsorb to is that one of the reactants is held in place in the correct orientation for reaction, therefore rate of reaction increases further. Also, they can be used to make only 1 optical isomer (due to 1 being held in place much like how enzymes work) if there are more than 1 which can be useful for many reasons. :smile:

Reply 678

Stevo F

18

Original post by Hullabaloo2803

Hello all

I was wondering if someone could help me, im just a bit confused on chromotography, is it:
Tlc- seperates by Adsorption and Gc- seperates by relative solubility?

almost.. all types of chromatography other than G/L seperate by adsorption, G/L seperates by boiling point and solubility, the greater the solubility the longer the retention time and the greater the boiling point the longer the retention time :smile:

Reply 679

LifeIsGood

12

Original post by Stevo F

no that's a property of any catalyst, that its not used up, a bonus with "fixed" catalysts that compounds adsorb to is that one of the reactants is held in place in the correct orientation for reaction, therefore rate of reaction increases further. Also, they can be used to make only 1 optical isomer (due to 1 being held in place much like how enzymes work) if there are more than 1 which can be useful for many reasons. :smile:

Ah ok thanks! Learnt something new :biggrin:

OCR A Chemistry F324 Rings, Polymers and Analysis Thu 26 Jan 2012

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