April 28, 2024, 07:17:05 PM
Forum Rules: Read This Before Posting


Topic: 3-hydroxybenzaldehyde  (Read 5380 times)

0 Members and 1 Guest are viewing this topic.

organicstudent

  • Guest
3-hydroxybenzaldehyde
« on: March 04, 2006, 11:11:54 PM »
I've been having trouble digging up any information about 3-hydroxybenzaldehyde.  First of all, is it acidic, basic, or neutral (my guess is that it's either acidic or neutral)?  Also, would its hydroxy group make it act as an alcohol?  Would it react with sodium to form hydrogen gas and sodium alkoxide?

Offline Alberto_Kravina

  • Assault Chemist
  • Retired Staff
  • Full Member
  • *
  • Posts: 608
  • Mole Snacks: +70/-15
Re:3-hydroxybenzaldehyde
« Reply #1 on: March 05, 2006, 11:13:08 AM »
I believe that it reacts with sodium, yeah...about the pH...I think that it is neutral or VERY WEAK acidic. Alcohols have pKa values around 15-20
« Last Edit: March 05, 2006, 11:17:19 AM by Alberto_Kravina »

hereafter

  • Guest
Re:3-hydroxybenzaldehyde
« Reply #2 on: March 05, 2006, 09:11:25 PM »
mild acid, it reacts with sodium to afford salt.

Offline movies

  • Organic Minion
  • Retired Staff
  • Sr. Member
  • *
  • Posts: 1973
  • Mole Snacks: +222/-21
  • Gender: Male
  • Better living through chemistry!
Re:3-hydroxybenzaldehyde
« Reply #3 on: March 09, 2006, 11:55:20 AM »
It's a phenol, so it acts like an acid, not an alcohol.  It will react with sodium, however, just like an acid would.  Sodium metal can also react with carbonyl groups as well though.

The pKa of phenol is 10, so the added electron withdrawing group should drop that a little bit to about 8.

Offline HP

  • Chemist
  • Full Member
  • *
  • Posts: 350
  • Mole Snacks: +33/-5
  • Gender: Male
Re:3-hydroxybenzaldehyde
« Reply #4 on: March 09, 2006, 12:13:02 PM »
I am wondering if the preformed Na-phenolate can exist as some isomeric quinone form and what structure such compound  ??? If quinone formed then may be some condensation or even polycondensation reaction could take place at the flask...
xpp

Offline movies

  • Organic Minion
  • Retired Staff
  • Sr. Member
  • *
  • Posts: 1973
  • Mole Snacks: +222/-21
  • Gender: Male
  • Better living through chemistry!
Re:3-hydroxybenzaldehyde
« Reply #5 on: March 10, 2006, 06:12:55 PM »
Well, you can't get to the quinone form in this case because the substituents are meta to one another.  If they were ortho or para, then you could draw a resonance structure that looks kind of like a quinone.

These quinones where one part is a C=O group and the other is a C=C group are called quinone methides.  Ortho-quinone methides can be used as dienes in Diels-Alder chemistry.  This has been studied extensively by people like Corey (Harvard), Pettus (UC-Santa Barbara), and lots of others.

Sponsored Links