Author Topic: CTH compilation, questions, future directions  (Read 4277 times)

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indole_amine

  • Guest
nice!
« Reply #20 on: November 13, 2004, 05:06:00 AM »
Maybe salting out the amine (with Na2CO3 for example, or simply NaCl) would help in getting a more efficient extraction? And I seem to remember that multiple extractions should preferably be done using the same volume for each single extraction, let's say three extractions using 200 + 200 + 200ml, and then maybe one last one with 30ml if you didn't wait until separation is complete (or if you're simply meticulous  ;) )...

And, just a thought; but maybe something around room temp. would be better than 0°C, regarding reaction kinetics as well as the change of physical solubility/miscibility of the different reactands and intermediates with varying temps....  :)


indole_amine

Dope_Amine

  • Guest
She always used brine.
« Reply #21 on: November 13, 2004, 11:19:00 AM »
She always used brine.  Those details were just left out.  I suppose I should add that she added everything but 'tone and Pd/C in an ice bath, then 'tone and stir for an hour, then Pd/C.  She likes it ice cold.  Maybe she'd consider it a good possibility to stir for 2 days ice cold, then 1 day rt.  Interesting point about same volume extractions.  Yes this bee would bee meticulous enough to do a fourth time with 100 mls.


Rhodium

  • Guest
CTH process development aspects
« Reply #22 on: November 13, 2004, 05:01:00 PM »
This is a really good article which discusses the preparation, durability and disposal of palladium catalysts and compares the merits of various formate hydrogen donors.

Catalytic transfer hydrogenation: o-nitro anisole to o-anisidine, some process development aspects
P. Haldar and V.V. Mahajani

Chemical Engineering Journal, 104, 27-33 (2004)

(https://www.thevespiary.org/rhodium/Rhodium/pdf/cth.nitroarene2aniline.proc-dev.pdf)

Abstract
The catalytic transfer hydrogenation of o-nitro anisole to o-anisidine was studied in the temperature range 35–85°C with ammonium formate as H-donor and iso-propanol as solvent using Pd/C as catalyst above agitation speed 1000 rpm. The substrate feed concentration was varied in the range from 0.068 to 0.341 kmol/m3 while catalyst loading was in the range 1.25–10% (w/w) of o-nitro anisole. The intermediate, hydroxylamine, was detected. In 130 min, all o-nitro anisole was converted with 99% selectivity towards o-anisidine. The catalyst has considerable reusability and was regenerated after deactivation without any significance loss in activity. Reliable methods for product separation and treatment of aqueous stream obtained after washing and solvent recovery are proposed. The possibility of Fenton Chemistry to treat aqueous waste stream was explored and found suitable.