ATAR Notes: Forum

VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Chemistry => Topic started by: bec on May 03, 2008, 03:04:24 pm

Title: Organic chem
Post by: bec on May 03, 2008, 03:04:24 pm

I'm having trouble with finding reaction pathways...

For example, finding a reaction pathway for the reaction of ethene to produce ethylamine.

I don't really even know where to start to be honest - i was thinking ethene--> ethane--> ethylamine, but i don't know the conditions of the substitution reaction b/ween ethane and NH3 that could produce ethylamine, or even if that is possible...

can anyone explain this to me?

Title: Re: Organic chem
Post by: polky on May 03, 2008, 03:22:59 pm

Well how I do it is I draw out the structure of what you have and what you want to get.  I can't picture stuff in my head, so by drawing it out I can figure out what I need to do (Eg. break the double bond between the two carbons).

How I would do it is ethene -> ethanol (through addition of H2O) -> ethylamine + H2O (through the addition of NH3, the OH in the ethanol gets substituted for NH2).

I don't know if that's the preferred pathway, but yeah.

Also, catalysts need to be used.  For ethene to ethanol, I think the catalyst is H3PO4, and from ethanol to ethylamine+water... I don't know xD.  My textbook says alumina!

I don't know if that helped at all but I hope it did! :)

Title: Re: Organic chem
Post by: bec on May 03, 2008, 03:28:03 pm

hmm that helps a bit, but i think what i need is some kind of list of what produces what

eg. amines can be formed through substitution reactions between ammonia and alkanol; alkanols can be formed through addition reactions of alkenes or substitiution reactions of chloroalkanes

i only just found those two "rules" but i'm going to look for more.
if anyone wants to contribute to my list......

Title: Re: Organic chem
Post by: Mao on May 03, 2008, 03:49:19 pm

generally:

alkane + chlorine -(UV LIGHT)-> chloroalkane

chloroalkane + sodium hydroxide -> alkanol

alkanol + ammonia -> amine

EDIT: its approved =)
http://notes.vcenotes.com/?step=download&action=feedback&id=70
this has got the pathway condensed from 4 textbooks =)

Title: Re: Organic chem
Post by: bec on May 03, 2008, 03:54:29 pm

wow that sounds amazing...you couldn't send it to me could you? can you attach files to personal messages?

Title: Re: Organic chem
Post by: Mao on May 03, 2008, 03:56:07 pm

*deleted*

EDIT: its approved =)
http://notes.vcenotes.com/?step=download&action=feedback&id=70

Title: Re: Organic chem
Post by: bec on May 03, 2008, 03:58:55 pm

that's amazing, thanks so much!
i didn't realised you'd already attached it haha

Title: Re: Organic chem
Post by: lanvins on May 03, 2008, 06:46:17 pm

ester formation question?

1. Write the formula of the alkanol and carboxylic acid used to make the following ester; CH3CH2COOCH2CH3

for the alkanol i got CH3CH2CH2OH

for the carboxylic acid i got CH3CH2COOH

but the book says that wrong, what should i do?

Title: Re: Organic chem
Post by: Mao on May 03, 2008, 06:54:45 pm

CH3CH2COOCH2CH3

looking at that carbon:

it is bonded to a CH2 group to the left (1 bond)
and two oxygens on the right (one double, one single)
thats a total of four bonds, therefore, it belongs to the carboxylic acid.
that is, you should get propanoic acid

the chain that remains has two carbons, which makes ethanol, not propanol.

Title: Re: Organic chem
Post by: lanvins on May 03, 2008, 07:08:10 pm

oh i think i get it now, thanks