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VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Chemistry => Topic started by: RobM8 on June 04, 2011, 03:35:35 pm

Title: Esterification
Post by: RobM8 on June 04, 2011, 03:35:35 pm
Distinction between esterification and transesterification?
I have only seen the sates of the carboxylic acid, the alcohol and the resulting ester as (l), would you be incorrect to put the states of the produced ester, and the reacted carboxylic acid and alcohol as (aq) ?
Title: Re: Esterification
Post by: funkyducky on June 04, 2011, 04:29:35 pm
It would be ok to write the carb acid and alcohol as aqueous, but not the ester.
Title: Re: Esterification
Post by: luken93 on June 04, 2011, 04:30:05 pm
Esterification = Forming an Ester between a Carboxyl and an Alkanol, emitting water in the process
Trans = Swapping one ester with another, ie triglyceride -> 3x methyl esters.
Title: Re: Esterification
Post by: RobM8 on June 04, 2011, 09:23:16 pm
Thanks lads
Title: Re: Esterification
Post by: Aurelian on June 05, 2011, 10:59:24 am
Quote from: funkyducky on June 04, 2011, 04:29:35 pm
It would be ok to write the carb acid and alcohol as aqueous, but not the ester.

That is not correct.

Esterification does not occur in the presence of water; you cannot label the carboxylic acid or the alkanol as aqueous. This is not a reaction in aqueous solution, even though water may be *produced* by it.

The carboxylic acid, alkanol and ester would all be either (l) or (s).
Title: Re: Esterification
Post by: golden on June 05, 2011, 06:01:22 pm
Quote from: Aurelian on June 05, 2011, 10:59:24 am
Quote from: funkyducky on June 04, 2011, 04:29:35 pm
It would be ok to write the carb acid and alcohol as aqueous, but not the ester.

That is not correct.

Esterification does not occur in the presence of water; you cannot label the carboxylic acid or the alkanol as aqueous. This is not a reaction in aqueous solution, even though water may be *produced* by it.

The carboxylic acid, alkanol and ester would all be either (l) or (s).

Hmm. So if we had:
Ethanoic acid and ethanol, we would make the liquids and the product (ester) a liquid also even though water is 'produced' in the course?
Title: Re: Esterification
Post by: Aurelian on June 05, 2011, 06:50:47 pm
Quote from: golden on June 05, 2011, 06:01:22 pm
Quote from: Aurelian on June 05, 2011, 10:59:24 am
Quote from: funkyducky on June 04, 2011, 04:29:35 pm
It would be ok to write the carb acid and alcohol as aqueous, but not the ester.

That is not correct.

Esterification does not occur in the presence of water; you cannot label the carboxylic acid or the alkanol as aqueous. This is not a reaction in aqueous solution, even though water may be *produced* by it.

The carboxylic acid, alkanol and ester would all be either (l) or (s).

Hmm. So if we had:
Ethanoic acid and ethanol, we would make the liquids and the product (ester) a liquid also even though water is 'produced' in the course?

Yes that's right :)
Title: Re: Esterification
Post by: pi on June 05, 2011, 06:54:46 pm
Quote from: golden on June 05, 2011, 06:01:22 pm
Quote from: Aurelian on June 05, 2011, 10:59:24 am
Quote from: funkyducky on June 04, 2011, 04:29:35 pm
It would be ok to write the carb acid and alcohol as aqueous, but not the ester.

That is not correct.

Esterification does not occur in the presence of water; you cannot label the carboxylic acid or the alkanol as aqueous. This is not a reaction in aqueous solution, even though water may be *produced* by it.

The carboxylic acid, alkanol and ester would all be either (l) or (s).

Hmm. So if we had:
Ethanoic acid and ethanol, we would make the liquids and the product (ester) a liquid also even though water is 'produced' in the course?
Remember H2SO4 catalyst is also liquid, got marked down for writing (aq)
Title: Re: Esterification
Post by: jane1234 on June 05, 2011, 07:29:48 pm
Is there any general rules with writing states? Usually I just guess... ???
Title: Re: Esterification
Post by: luken93 on June 05, 2011, 07:55:52 pm
Quote from: jane1234 on June 05, 2011, 07:29:48 pm
Is there any general rules with writing states? Usually I just guess... ???
Amen to that hahaha
Title: Re: Esterification
Post by: scocliffe09 on June 06, 2011, 10:38:31 pm
Quote from: jane1234 on June 05, 2011, 07:29:48 pm
Is there any general rules with writing states? Usually I just guess... ???
For the reaction pathways, learn them.
Otherwise, use your knowledge of the molecules' properties to help you guess :)
Title: Re: Esterification
Post by: VivaTequila on June 08, 2011, 09:18:38 pm
Quote from: scocliffe09 on June 06, 2011, 10:38:31 pm
Quote from: jane1234 on June 05, 2011, 07:29:48 pm
Is there any general rules with writing states? Usually I just guess... ???
For the reaction pathways, learn them.
Otherwise, use your knowledge of the molecules' properties to help you guess :)

This, but as a general rule when anything is in the presence of water use H2O as a liquid and anything else as aq. Otherwise, know your precipitates in reactions, like AgCl and PbEverything.
Title: Re: Esterification
Post by: rena-bena on June 08, 2011, 11:03:28 pm
Alcohol and carb acid MUST be in liquid state. So is the ester. Otehrwise - no marks.
Chem Teacher.
Title: Re: Esterification
Post by: scocliffe09 on June 08, 2011, 11:53:49 pm
Quote from: VivaTequila on June 08, 2011, 09:18:38 pm
Quote from: scocliffe09 on June 06, 2011, 10:38:31 pm
Quote from: jane1234 on June 05, 2011, 07:29:48 pm
Is there any general rules with writing states? Usually I just guess... ???
For the reaction pathways, learn them.
Otherwise, use your knowledge of the molecules' properties to help you guess :)

This, but as a general rule when anything is in the presence of water use H2O as a liquid and anything else as aq. Otherwise, know your precipitates in reactions, like AgCl and PbEverything.
yeah this general rule is not great... see rena-bena's post...
Title: Re: Esterification
Post by: luken93 on June 09, 2011, 08:34:29 am
Okay, can we maybe just write some general rules down for these sorts of things.

Combustion:
Alkane(g) + O2(g)  -->   CO2(g) + H2O(g)

Esterification:
Alkanol (l) + Carboxylic Acid (l)  - H2SO4(l) ->  Ester (l) + H2O(l)

Hydrogenation:
Alkene(g) + H2(g)  - Ni ->  Alkane(g)

Halogenation:
Alkane(g) + Cl2(g)  - UV Light ->  Chloroalkane(g) + HCl(g)

Alkanol(aq)  - PCl5 ->  Chloroalkane(g)

Chloroalkane(g) - NaOH(aq) -> Alkanol(g) + NaCl(g)

Alkanol(aq) - Cr2O72-(aq) / H+(aq) -> Carboxylic Acid(aq)

Alkene(g) + H2O(g)  - H3PO4(aq) -> Alkanol(aq)

Feel free to clean up any of the ones I have mentioned, but that's what I've got in my notes...



Title: Re: Esterification
Post by: Mao on June 09, 2011, 06:49:12 pm
NaCl gas?
Title: Re: Esterification
Post by: luken93 on June 09, 2011, 08:18:44 pm
Quote from: Mao on June 09, 2011, 06:49:12 pm
NaCl gas?
Hahaha, I was just writing out what was on my summary sheet. I'll change that, but what about the rest?
Title: Re: Esterification
Post by: golden on June 11, 2011, 03:04:02 pm
Quote from: luken93 on June 09, 2011, 08:34:29 am
Okay, can we maybe just write some general rules down for these sorts of things.

Combustion:
Alkane(g) + O2(g)  -->   CO2(g) + H2O(g)

Esterification:
Alkanol (l) + Carboxylic Acid (l)  - H2SO4(l) ->  Ester (l) + H2O(l)

Hydrogenation:
Alkene(g) + H2(g)  - Ni ->  Alkane(g)

Halogenation:
Alkane(g) + Cl2(g)  - UV Light ->  Chloroalkane(g) + HCl(g)

Alkanol(aq)  - PCl5 ->  Chloroalkane(g)

Chloroalkane(g) - NaOH(aq) -> Alkanol(g) + NaCl(g)

Alkanol(aq) - Cr2O72-(aq) / H+(aq) -> Carboxylic Acid(aq)

Alkene(g) + H2O(g)  - H3PO4(aq) -> Alkanol(aq)

Feel free to clean up any of the ones I have mentioned, but that's what I've got in my notes...





Nice.

Does alkene (g) and steam go to alkanol (aq)?

Could some please confirm the aqueous part?
Title: Re: Esterification
Post by: scocliffe09 on June 11, 2011, 06:04:30 pm
Quote from: golden on June 11, 2011, 03:04:02 pm
Quote from: luken93 on June 09, 2011, 08:34:29 am
Okay, can we maybe just write some general rules down for these sorts of things.

Combustion:
Alkane(g) + O2(g)  -->   CO2(g) + H2O(g)

Esterification:
Alkanol (l) + Carboxylic Acid (l)  - H2SO4(l) ->  Ester (l) + H2O(l)

Hydrogenation:
Alkene(g) + H2(g)  - Ni ->  Alkane(g)

Halogenation:
Alkane(g) + Cl2(g)  - UV Light ->  Chloroalkane(g) + HCl(g)

Alkanol(aq)  - PCl5 ->  Chloroalkane(g)

Chloroalkane(g) - NaOH(aq) -> Alkanol(g) + NaCl(g)

Alkanol(aq) - Cr2O72-(aq) / H+(aq) -> Carboxylic Acid(aq)

Alkene(g) + H2O(g)  - H3PO4(aq) -> Alkanol(aq)

Feel free to clean up any of the ones I have mentioned, but that's what I've got in my notes...





Nice.

Does alkene (g) and steam go to alkanol (aq)?

Could some please confirm the aqueous part?
depends entirely on the length of the alkanol - short ones would be aq and longer ones liquid.
Title: Re: Esterification
Post by: luken93 on June 11, 2011, 09:27:39 pm
is this why they have the states in the data book?

Also, is it just better we know whether it's aq/l (hence polar/non-polar) as opposed to whether it's gaseous?