March 28, 2024, 02:49:58 PM
Forum Rules: Read This Before Posting


Topic: cis-trans 1,4-diphenyl-1,3-butadiene  (Read 769 times)

0 Members and 1 Guest are viewing this topic.

Offline xshadow

  • Full Member
  • ****
  • Posts: 427
  • Mole Snacks: +1/-0
cis-trans 1,4-diphenyl-1,3-butadiene
« on: October 20, 2020, 08:28:18 AM »
Someone can tell me the boiling point of the cis trans isomer

Checking online I found that the trans-trans isomer has  350°C as boiling point
Thanks

Offline chenbeier

  • Sr. Member
  • *****
  • Posts: 1348
  • Mole Snacks: +102/-22
  • Gender: Male
Re: cis-trans 1,4-diphenyl-1,3-butadiene
« Reply #1 on: October 20, 2020, 08:45:55 AM »

Offline AWK

  • Retired Staff
  • Sr. Member
  • *
  • Posts: 7981
  • Mole Snacks: +555/-93
  • Gender: Male
Re: cis-trans 1,4-diphenyl-1,3-butadiene
« Reply #2 on: October 20, 2020, 09:34:39 AM »
This is the value calculated by ACD/Labs.
I cannot believe that at this temperature the compound will not isomerize to the (E, E) isomer with the known boiling point of 353°C.
AWK

Offline chenbeier

  • Sr. Member
  • *****
  • Posts: 1348
  • Mole Snacks: +102/-22
  • Gender: Male
Re: cis-trans 1,4-diphenyl-1,3-butadiene
« Reply #3 on: October 20, 2020, 09:47:44 AM »
Probably this happens 12 K is a big Delta already. 367 °C - 12 °C = 355 °C but it could also be 379°C

Offline xshadow

  • Full Member
  • ****
  • Posts: 427
  • Mole Snacks: +1/-0
Re: cis-trans 1,4-diphenyl-1,3-butadiene
« Reply #4 on: October 20, 2020, 12:24:50 PM »
....Because I made the trans-trans  1,4-diphenyl -1,3 -butadiene with WIttig.
But I also get some impuritiy of the cis-trans isomer and some of the triphenyl phosphine oxide.

Using gascromatografy the main peak (trans-trans) arrives after 12.8min

But I also get two very small peak:
one at  11.5min
the other at 14min

I think the peak at 14min is the triphenyl phosphine oxide (more polar)
Don't know why the trans-trans has a higher B.P/ polarity than the cis-trans
 

Sponsored Links