The Vespiary

The Hive => Chemistry Discourse => Topic started by: TheHobbit on June 27, 2003, 10:15:00 PM

Title: Large Scale Benzo Production
Post by: TheHobbit on June 27, 2003, 10:15:00 PM: What would be the easiest way for swim to mass produce benzo? The h2o2/i2 synth is easy but when scaled up more than 2.5x the temp is WAY too hard to control and too high of a temp results in an inpure benzo outcome that swim hasn't figured out how to purify to pure benzo without losing a lot of the yield.

The only bad thing about the h2o2/i2 synth is it takes way too damn long to make large amounts. The other synths on Rhodium's benzo page use relatively the same amount of hydro, 55-100g at a time. Which would be the easiest to scale up?

The nitrogen dioxide route may be promising but swim doesn't know how easily it would scale up. Swim also doesn't have a source for NO2.
Title: I've done that h2O2 benzo synth at 3x scale...
Post by: yinga on June 28, 2003, 05:47:00 PM: I've done that h2O2 benzo synth at 3x scale before without a problem. I don't see how temp control becomes an issue at a larger scale, and the time stays the same as well at any scale.
Title: The time isssue is if I need say 1200g of...
Post by: TheHobbit on June 28, 2003, 07:26:00 PM: The time isssue is if I need say 1200g of benzo, I have to do atleast 10 batches, which means like 3-4 days of non-stop reactions for it.

The temp control issue has been a problem for me, while adding the h2o2 I have had the temp spike to almost 60°, even with an ice water bath. I have noticed that the higher the temp gets the less pure my benzo gets.
Title: Lab work takes time, so what?
Post by: Rhodium on June 29, 2003, 01:12:00 AM: If you are going to have use for 1200g of p-benzoquinone right this moment, it means that you are planning to process around 1.5 kg of safrole, and thus end up with ~0.75 kg MDMA - isn't it worth working for a few days to achieve that?

P.S. It isn't forbidden to run several p-Benzoquinone syntheses in parallell, you don't need do do them all sequentially.
Title: For those who have done it
Post by: gabd on June 30, 2003, 04:36:00 AM: is the p-benzo obtained yellow?
I ask because I've used peen-green benzo and I feel like trying this synth.
It seems easy, less expensive then buying benzo. The quality of the benzo must have an effect on the yield.
I believe pee green benzo is a mix of benzo and hydroquinone, so maybe there is less real benzo then I think in my reaction medium.
Title: green benzo
Post by: Vitus_Verdegast on June 30, 2003, 02:58:00 PM: I believe pee green benzo is a mix of benzo and hydroquinone

I have used 98% p-benzoquinone from Acros, from a freshly opened bottle and it was colored pea green. Never had any problems with it yieldwise.

- I'm pretty sure p-benzoquinone still isn't scheduled in the USA, only watched.
Title: Its good to know
Post by: gabd on June 30, 2003, 03:45:00 PM: I've always been under the impression that pure benzo was yellow, as it says on some msds sheets I've looked at.
The p-benzo I've used before was of photo grade(photo supplier told me that) and it was peen green.
Even more, reading on msds sheets, it says benzo should always be stored in a glass bottle where as I get it in a plastic jar. Anyone know what effect that could have on the quality of the benzo?
Title: yellow and green p-benzoquinone
Post by: Vitus_Verdegast on June 30, 2003, 06:18:00 PM: Pure p-benzoquinone is yellow, but even minor contamination colors the product greenish. My p-benzoquinone is of 98% purity :

(https://www.thevespiary.org/rhodium/Rhodium/hive/hiveboard/picproxie_docs/000442977-file_oqfw.jpg)

I don't remember the prices off-hand, but there was a big price difference between the 98% and 99% stuff, the 99% was alot more expensive.

After opening and using the bottle was stored in the freezer for more than a year, and still the colour hasn't changed:

(https://www.thevespiary.org/rhodium/Rhodium/hive/hiveboard/picproxie_docs/000442977-file_ejva.jpg)

(https://www.thevespiary.org/rhodium/Rhodium/hive/hiveboard/picproxie_docs/000442977-file_buik.jpg)

I guess a simple washing would give the yellow stuff, but for a Wacker oxidation this green p-benzoquinone still works fine.

I can't say why catechol and NaBH₄ do come in dark glass bottles, but not p-benzoquinone .
Perhaps a dark glass bottle is only necessary for the pure yellow p-benzoquinone?
Title: setup for 3x p-benzo via h2o2
Post by: homeslice on July 02, 2003, 07:32:00 AM: Swims wondering about the setup that is used for a 3x synth scale for the benzo to p-benzo via h2o2. Every detail is useful. Swims about to attempt a 1x scale tomorrow morning with a 1000ml erlenmeyer and a 3" octagonal stir bar equipped with a claisen adapter and a therm and a 500ml sep 24/40. Its finally, after failed a few times with shoddy set ups, the exact setup as described per rhodiums site. Any other help or suggestions would be appreciated, especially the setup for the 3x synth.

Thanks
homeslice
Title: setup not important
Post by: yinga on July 03, 2003, 05:30:00 PM: The exact details for the procedure are not very important. At the 55g scale, a 1000ml erlenmeyer is probably too big, and a 3" stir bar is way too big (you only have 115 g of solvent!). As long as you have sufficient control of the temperature, which can be easily achieved with a water bath (you can add warm or cold water as often as you wish). At the 3x scale, SWIM used a 3-neck 500 ml flask, 250ml addition funnel, and egg-shaped stirbar.