tag:blogger.com,1999:blog-4387100009341358284.post7579965322664728782..comments2024-03-12T09:55:15.923+01:00Comments on Curly Arrow: Catalytic Hydrogenation Part III - More Tips and TricksDaniel Sejerhttp://www.blogger.com/profile/12498255536497699232noreply@blogger.comBlogger10125tag:blogger.com,1999:blog-4387100009341358284.post-51768382944816639012012-06-05T09:52:35.515+02:002012-06-05T09:52:35.515+02:00another good way to work up a catalytic hydrogenat...another good way to work up a catalytic hydrogenation is via centrifugation. pour the reaction mixture into a falcon and centrifuge at 2000 rpm. The resulting supernatant can be filtered throgh a PTFE more smoothly.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-4387100009341358284.post-32793364817347410592011-04-15T01:10:02.854+02:002011-04-15T01:10:02.854+02:00One way to filter off your catalyst without using ...One way to filter off your catalyst without using celite is through a PTFE membrane filter (like from Millipore 0.2um) over a glass frit sealed with clamp. The setup is sold through VWR (26316-690) and you just attach it over a vacuum adapter and filter directly into a round bottom. You're left with a neat little round pile of catalyst on the membrane and there's less metal waste to Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-4387100009341358284.post-4652599574959616382010-04-14T13:28:50.207+02:002010-04-14T13:28:50.207+02:00Thank you Milkshake, most appreciated!Thank you Milkshake, most appreciated!Danielnoreply@blogger.comtag:blogger.com,1999:blog-4387100009341358284.post-26354989062561622272010-04-11T01:56:36.100+02:002010-04-11T01:56:36.100+02:00I would use 0.5g-1g of 10% Pd-C (or a Pearlmann ca...I would use 0.5g-1g of 10% Pd-C (or a Pearlmann cat) for 5 g of starting material. <br /><br />If the hydrogenation does not proceed fast enough, rather than adding more catalyst it is better to increase the temperature, for example to continue under H2 baloon ontop of a reflux condenser. You can do fast benzylamine debenzylations in diluted aqueous HCl as a solvent at 80-100C under H2 baloon, milkshakehttps://www.blogger.com/profile/08188961610554710616noreply@blogger.comtag:blogger.com,1999:blog-4387100009341358284.post-13805958907048954592010-04-10T17:46:41.502+02:002010-04-10T17:46:41.502+02:00Silly question, how much catalyst typically used f...Silly question, how much catalyst typically used for debenzylation? (mol equivalent to substrate)...thanks!Unknownhttps://www.blogger.com/profile/17520653165985471882noreply@blogger.comtag:blogger.com,1999:blog-4387100009341358284.post-264036321588171232010-04-07T03:00:33.342+02:002010-04-07T03:00:33.342+02:00Actually, the mechanisms by which deuterium (and t...Actually, the mechanisms by which deuterium (and tritium) are diluted by hydrogen in a catalytic reduction are not bypassed by merely using a nonprotic solvent. Often a protic solvent will minimize exchange. If you stir ethyl acetate over a catalyst with an atmosphere of isotopic hydrogen, the ethyl acetate will be labeled. This dilutes the isotopic hydrogen with 1H. The maximum incorporation of Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-4387100009341358284.post-21779510839761525052010-04-04T17:46:29.922+02:002010-04-04T17:46:29.922+02:00@Milkshake, as my old boss used to say if you deli...@Milkshake, as my old boss used to say if you deliver clean compounds on tme I don't care how you make them. As I have indicated I'm a Celte fan. However, you are correct about the fine particles that may pass through. This is exactly why selecting a good Celte is important. I think I forgot to mention that I always pre-wash the Celite with an approprate organic solvent after packing to Daniel Sejerhttps://www.blogger.com/profile/12498255536497699232noreply@blogger.comtag:blogger.com,1999:blog-4387100009341358284.post-32517490744187538592010-04-02T00:29:39.252+02:002010-04-02T00:29:39.252+02:00I think the mysterious nobelist that is visiting y...I think the mysterious nobelist that is visiting you is Obama, because your site has successfully avoided having too mcuh recent activity and therefore it became a very peaceful place to visit. <br /><br />(By the way, if you write your personal web content never ever apologize to your readers for lack of recent postings. They are bunch of freeloaders and therefore not entitled to get frequent milkshakehttps://www.blogger.com/profile/08188961610554710616noreply@blogger.comtag:blogger.com,1999:blog-4387100009341358284.post-91336920645042363272010-04-01T11:29:23.575+02:002010-04-01T11:29:23.575+02:00Celite 545 will dissolve in acetic acid! then what...Celite 545 will dissolve in acetic acid! then what should you do if your reaction is in acetic acid? Well at least this explains my ridiculous crude yield currently! Keep up the good work with the blog, very informative!Unknownhttps://www.blogger.com/profile/14671604676067691293noreply@blogger.comtag:blogger.com,1999:blog-4387100009341358284.post-86130809629522883672010-04-01T00:14:03.836+02:002010-04-01T00:14:03.836+02:00"I seem to have developed a life with other a..."I seem to have developed a life with other areas of interest than chemistry" - this was pretty awesome :)<br />Your posts are so useful and funny (just opposite to everything I learnt during my studies), please don't stop updating your blog!Asiahttps://www.blogger.com/profile/04201565025937166095noreply@blogger.com