10-22-02 08:47
No 371274
Enjoy
Patent GB955227
Patent GB765042
Catalytic hydrogenation freak
(Hive Addict)
10-23-02 18:09
No 371989
I just got the sigma brochure on safe phosphogenations, using a heating of diphosgene in the presence of a catalyst...
quite nice...
Infinite Radiant Light - THKRA
(Stranger)
10-24-02 15:59
No 372335
Diphosgene is far from a safe compound. It is a very noxious heavy liquid (density = 1.65 g / cm3), with a vapour pressure of 10 mm Hg at 20 °C.
It is produced by the photochlorination of
ClCOOCH3 or HCOOCH3
Furthermore, it isn't a stable molecule: it tends to decompose into phosgene ... (Fe2O3 cathalyses the decomposition and I think also pyridine - if my memory serves me right).
Triphosgene is the safe alternative, since it is a crystalline compound (easy to work with) and the most important: it is stable. One molecule of triphosgene is equivalent to three molecules of phosgene. I used it once to make some isocyanate.
Why don't you use one of those fine coupling reagentia they use in peptide chemistry (TBTU, DCC, BOP, pyBOP, water soluble carbodiimide to name a few). These reagents are far more convenient than those nasty phosgene compounds.
Veerle //
(Stranger)
10-24-02 20:21
No 372394
You mean the route for coupling using DCC (carbodicyclohexylimide?) in the presence of HOBt.
../rhodium /et2lsd.
Regentia is plural for reagent? Thats a new one on me.
(Stranger)
10-24-02 22:28
No 372436
I didn't know that this file was available. Yes, thats what I mean.
Reagentia is the plural for reagent in my language. In English it is probably reagents. But, this is not a linguistic forum, is it?
Veerle //
Oderint dum metuant. (chew on this, you linguists)
(Moderator)
10-25-02 15:14
No 372681
Be VERY careful with diphosgene or triphosgene They always decompose into phosgene in their container and under the reaction conditions. The same security measurements have to be used like with handling phosgene itself, e.g. using a good fumehood. The only advantage of diphosgene and triphosgene is that they are easier to handle as a liquid and a solid, respectively, compared to the gas phosgene.
(Master Searcher)
10-25-02 15:20
No 372682
You could look through this subclass.
http://patft.uspto.gov/netacgi/nph-Parse
http://www.geocities.com/dritte123/PSPF.
The hardest thing to explain is the obvious
(Stranger)
10-25-02 17:38
No 372709
Lilienthal, I agree that diphosgene is a rather hazardous chemical. But triphosgene is absolutely safe. OK, you 'd better place the triphosgene flask in the fridge, but I NEVER had any problems with it when I did the reaction. My advice would be: use triphosgene, don't mess with diphosgene & use only phosgene if you have an ABC (Atomic, Biologic & Chemical warfare) suit. A good fumehood won't do, if you mess with phosgene.
(Hive Addict)
10-25-02 18:42
No 372717
Yes, it was the premier war gas until mustard came along... long exposure, no symptoms, just makes cigarettes taste metallic... very deadly at low levels... they used both di and tri phosgene in the apparatus..
Need a chem agent mask for this one though..
Infinite Radiant Light - THKRA
(Moderator)
10-26-02 03:34
No 372832
And back to the topic: Why not use up-to-date reagents like pyBOP Post 353379 (Rhodium: "New LSD analogs from the Nichols Lab", Tryptamine Chemistry)?
(Stranger)
10-26-02 03:44
No 372833
Yup, pyBOP looks very nice. And it looks like not suspicious if you order it in combination with a couple amino acids
.
10-27-02 12:52
(Rated as: offending)