(Chief Bee)
06-14-02 11:12
No 321303
      Piperic acid from black pepper
(Rated as: good read)

(1) Place 30g of finely ground black pepper in a porous thimble in the central chamber of a soxhlet extractor and 175ml of 95% ethanol in a RB flask. Gently heat solvent under reflux for 6 hours. Concentrate the solution to a volume of 20-30ml on a rotary evaporator and add 30ml of warm 2M ethanolic potassium hydroxide (this is ESSENTIAL to keep all the acidic components in solution). After shaking the warm mixture well, filter the solution and remove any insoluble materials (quite a bit). While keeping the solution warm over a water bath, and water until no more yellow solid forms. Allow the resulting solution to stand overnight and then isolate yellow precipitate that has formed by filtration. Recrystalise the crude product in hot 3:2 acteone/hexane, cooling in ice bath if necessary to promote recyrstallisation. The resulting product (Piperine) is in the form of spectacular yellow needles, a yield of around 2g (in my case) was obtained.

(2) Hydrolysis of Piperine to Piperic Acid: (These intructions are in the small scale, obviously they can be increased) Heat mixture of 0.1g piperine and 10ml of 2M ethanolic potassium hydroxide under reflux for 1.5h. Evaporate the ethanolic solution to dryness under vacuum. Suspen the solid potassium piperate that remains in the flask in about 5ml of hot water and carefully acidify the suspension with 6M HCL. Collect the precipitate, wash with cold water, recyrystalise from COLD ethanol. The mp of the product should be around 206C (a little less than the literature values due to the slight Chavacine impurification (Chavacine is the Z,Z isomer of piperic acid (E,E))
06-14-02 22:49
No 321555
      I remember this  Bookmark   

Swim remembers reading this from your page rhodium. yes. SWIM loved this very much seeing how his neighbor has a big piper nigrum tree. SWim tried this once, but scaled up to 50 g of pepper. it does work. Swim got 2.5 g of beautiful needles. So when are they going to start reporting sales of black pepper??wink
(Hive Bee)
06-16-02 12:29
No 322147
      yeah, I tried this too...  Bookmark   

I just can't stand the strong pepper smell after a while.  It gives me the biggest fucking headache!frown

Do not go gentle into that good night.  Rage, Rage, against the dying of the light.  --Dylan Thomas