April 24, 2024, 08:43:47 PM
Forum Rules: Read This Before Posting


Topic: Aceteic anhydride reaction...  (Read 8234 times)

0 Members and 1 Guest are viewing this topic.

Offline prncess23

  • Regular Member
  • ***
  • Posts: 64
  • Mole Snacks: +0/-0
Aceteic anhydride reaction...
« on: May 10, 2009, 04:14:39 AM »
what are the major products of the reaction of acetic anhydride with:
a. diphenylamine
b. water 0with heat)
c. benzene in the presence of a Lewis acid
d. toluene in the presence of a Lewis acid
e. ethanol (with heat)

Offline sjb

  • Global Moderator
  • Sr. Member
  • ***
  • Posts: 3652
  • Mole Snacks: +222/-42
  • Gender: Male

Offline prncess23

  • Regular Member
  • ***
  • Posts: 64
  • Mole Snacks: +0/-0
Re: Aceteic anhydride reaction...
« Reply #2 on: May 10, 2009, 04:36:46 AM »
ok. cool so...ill do the easy one first...water...

b. (CH3CO)2O + H2O → 2 CH3CO2H

Offline StarvinMarvin

  • Chemist
  • Regular Member
  • *
  • Posts: 86
  • Mole Snacks: +5/-6
  • Gender: Male
Re: Aceteic anhydride reaction...
« Reply #3 on: May 10, 2009, 01:37:22 PM »
to do the rest, (if you still have not figured out how to do it) try to look up reactions of alcohols and reactions of amines inany organic chemistry textbook. Or even on wikipedia.

Offline macman104

  • Retired Staff
  • Sr. Member
  • *
  • Posts: 1644
  • Mole Snacks: +168/-26
  • Gender: Male
Re: Aceteic anhydride reaction...
« Reply #4 on: May 10, 2009, 04:56:05 PM »
These are all roughly the same, just different nucleophiles, no?

Offline StarvinMarvin

  • Chemist
  • Regular Member
  • *
  • Posts: 86
  • Mole Snacks: +5/-6
  • Gender: Male
Re: Aceteic anhydride reaction...
« Reply #5 on: May 10, 2009, 06:01:37 PM »
basically, yes. With the small exception of c and d which have to be regarded rather separately.

Offline macman104

  • Retired Staff
  • Sr. Member
  • *
  • Posts: 1644
  • Mole Snacks: +168/-26
  • Gender: Male
Re: Aceteic anhydride reaction...
« Reply #6 on: May 10, 2009, 06:07:02 PM »
Even then, your nucleophile can be regarded as the electron pair from the ring, attacking the electrophilic carbonyl (made more electrophilic by the complexation of the lewis acid).

It's not super relevant, but it helped tremendously for me when I recognized how common most organic reactions are, and I think it's well illustrated in this question.

Offline prncess23

  • Regular Member
  • ***
  • Posts: 64
  • Mole Snacks: +0/-0
Re: Aceteic anhydride reaction...
« Reply #7 on: May 10, 2009, 06:10:29 PM »
ok so i got all the answers except c.

a. acetic anhyride + diphenylamine= n.n-diphenylacetamide + acetic acid
b. acetic anhyride + water (with heat)= 2 acetic acid
c. acetic anhyride + benzene --->lewis acid--->acetophenone + acetic acid
d. toluene in the presence of a Lewis acid
e. acetic anhyride + ethanol (with heat)= ethyl acetate + acetic acid

how do i d?

Offline macman104

  • Retired Staff
  • Sr. Member
  • *
  • Posts: 1644
  • Mole Snacks: +168/-26
  • Gender: Male
Re: Aceteic anhydride reaction...
« Reply #8 on: May 10, 2009, 06:43:28 PM »
Same way you did c.  Except the methyl group influences where the substitution is going to occur.  I assume you are familiar with friedel-crafts acylation?  Do you know about ortho/para directing groups?

Offline prncess23

  • Regular Member
  • ***
  • Posts: 64
  • Mole Snacks: +0/-0
Re: Aceteic anhydride reaction...
« Reply #9 on: May 10, 2009, 07:16:24 PM »
yes i am...but...is the product still going to be acetophenone???

Offline macman104

  • Retired Staff
  • Sr. Member
  • *
  • Posts: 1644
  • Mole Snacks: +168/-26
  • Gender: Male
Re: Aceteic anhydride reaction...
« Reply #10 on: May 10, 2009, 07:33:40 PM »
Not quite, you aren't using benzene anymore, you're using toluene.

What carbons on the ring are favored by the methyl group for substitution (is it ortho/para directing or meta-directing)?  This will dictate which carbons the acetyl group will most likely attach to.

Sponsored Links