tag:blogger.com,1999:blog-7726130056398324774.post6481969388440284160..comments2023-12-11T21:36:11.801+10:00Comments on Round Bottom Flask: RBF Teaches: Drying solventsMSGhttp://www.blogger.com/profile/08254326589743221405noreply@blogger.comBlogger15125tag:blogger.com,1999:blog-7726130056398324774.post-14280579272249569632012-02-09T16:53:20.596+10:002012-02-09T16:53:20.596+10:00Do you know how to keep a good mood. Just remember...Do you know how to keep a good mood. Just remember to pay attention to the fashion trend of <a href="http://www.hermesshophandbags.com/" rel="nofollow">Kelly Hermes Bag</a> such as <a href="http://www.hermesshophandbags.com/" rel="nofollow">Hermes Birkin Bag Price</a> or the other styles like <a href="http://www.cambridge-satchel.org/" rel="nofollow">cambridge satchel</a>. I promise you will relax yourself. So come on, know more fashion style arround you and make yourself more confidence. You will like it.goodshoppinghttps://www.blogger.com/profile/06201448419904030443noreply@blogger.comtag:blogger.com,1999:blog-7726130056398324774.post-64580282081513882812011-02-25T19:53:53.990+10:002011-02-25T19:53:53.990+10:00Excellent advice thank you :-)Excellent advice thank you :-)Fun Casino Hire Sheffieldhttp://www.casinohireuk.com/fun_casino_sheffield.htmnoreply@blogger.comtag:blogger.com,1999:blog-7726130056398324774.post-10244276627759789182010-05-10T14:46:26.225+10:002010-05-10T14:46:26.225+10:00Thanks Labchimp :)Thanks Labchimp :)ChemGradhttps://www.blogger.com/profile/18304732744053614163noreply@blogger.comtag:blogger.com,1999:blog-7726130056398324774.post-68770961974589493082010-05-10T11:14:51.924+10:002010-05-10T11:14:51.924+10:00Ahh Lab Chimp, you are my hero. Except for those f...Ahh Lab Chimp, you are my hero. Except for those few times you sent me to Andrei you gave me so much knowledge. I am so much better at chemistry thanks to you.OrganicOverdosehttps://www.blogger.com/profile/06308937714718821761noreply@blogger.comtag:blogger.com,1999:blog-7726130056398324774.post-59713962802012175362010-05-09T18:06:30.520+10:002010-05-09T18:06:30.520+10:00With your bubbler system how do you evacuate your ...With your bubbler system how do you evacuate your flask then back-purge with inert gas? Surely you get silicon oil being sucked back all the time into your make-do-traps? <br /><br />If you are lucky enough to have a postdoc in your group you need to take full advantage of him/her. Sure you will make mistakes and you will learn from your mistakes. But do you want to learn from your mistakes by losing an eye (or two) or by being exposed to some nasty chemical? They essentially have a duty of care for you, so if you ask them "is this setup correctly" and they say get fracked and you end up in hospital because Acetonitrile/HF/HMPA or whatnot boiled in your face, it's not your fault it's theirs. However, on the other hand there is common sense which they cant fix.<br /><br />end of rant<br /><br />To cut this long story short you need to drain as much/all information from your postdoc as possible. It will greatly assist you to develop your experimental skills.Labchimphttps://www.blogger.com/profile/01132553734893580232noreply@blogger.comtag:blogger.com,1999:blog-7726130056398324774.post-31690478776181388982010-05-09T17:43:08.070+10:002010-05-09T17:43:08.070+10:00I use an improvised bubbler like this one:
http:/...I use an improvised bubbler like this one:<br /><br />http://img.photobucket.com/albums/v504/ASALA/1111.jpg?t=1273389578<br /><br />with metal rod attached to the host-manifold. Since the oil tend to flow out and blocked the host and contaminate the manifold, I use rubber stopper vial (syringes on each end of the host into the vial) ie. as the oil trapper. Not very impressive, I think it makes more sense now that I might turned up the gas too high because of this. <br /><br />I will try redo the ACN purification with CaH2 for few hours (or overnight?) before continue with distillation.<br /><br />OMG I feel so pressure that I only have 2 schlenk lines working for anhydrous reactions. I have lots of them to go :(<br /><br />Yes, we have a Posdoc here and few very-noob PhDs, no senior PhD. I usually approach her about chemistry and try attempt technical problems like this myself.ChemGradhttps://www.blogger.com/profile/18304732744053614163noreply@blogger.comtag:blogger.com,1999:blog-7726130056398324774.post-65073832134357907812010-05-09T17:12:53.550+10:002010-05-09T17:12:53.550+10:00Couple of things u can try. Stir the acetonitrile ...Couple of things u can try. Stir the acetonitrile with CaH2 without refluxing for a few hours in the distillation apparatus to quench any remaining water. What kind of bubbler system do you have? Perhaps your N2 or Ar was turned up to high? Any blockages in the system? Was there inert gas venting through your check bubbler/valve? You could attach a y-tube to your distillation setup one with inert gas going in and another bubbler at the other end of the Y tube. If you are sure everything is unblocked you could try using Keck clips on the joints. Too much grease?<br /><br />I'm assuming you have a postdoc or senior PhD student to assist with such matters? Probably not a good idea for a new student to be left to their own devices ;)<br /><br />As for your schlenk line. If you use too much glue u will end up gluing the tap to the glass and then u will be screwed (no pun intended). If you get the right amount of glue and if u think u can stick plastic onto teflon, good luck with that. Otherwise i would take that manifold to the glassblower to get him to sort that out. If thats not an option test to see if the schlenk line has a leak at that spot. If not then maybe u can live without one of the lines. Probably not a good idea to be turning on the high vac with a Liquid N2 trap if you have a leak there.<br /><br />300C seems excessive to distill acetonitrile which boils at 82C. Maybe the thermosat controller is borked. I hate those controllers you dip into the oil.Labchimphttps://www.blogger.com/profile/01132553734893580232noreply@blogger.comtag:blogger.com,1999:blog-7726130056398324774.post-25181517881389142222010-05-09T17:06:57.223+10:002010-05-09T17:06:57.223+10:00This comment has been removed by the author.Labchimphttps://www.blogger.com/profile/01132553734893580232noreply@blogger.comtag:blogger.com,1999:blog-7726130056398324774.post-70726254754074565992010-05-09T15:37:00.166+10:002010-05-09T15:37:00.166+10:00Yes, I did. I connected the hose from manifold for...Yes, I did. I connected the hose from manifold for inert gas to fill the whole system. It is strange that the pressure tend to build up faster and pushed thermometer rather than traveling down the end of the condenser and released through that hose. I heated up the oil bath to the solvent at 300C, otherwise it won't distill. I reckon, despite the low bp, ACN is very polar and that might contribute to the difficulty to vaporise.<br /><br />Yes, I am using the Young's type adapter in the manifold, well spot on. My problem is the black cap snapped off from the white inside. Somebody turn the cap too tight to close the line and broke it *sigh* <br /><br />I am working in a brand new Research Institute, unlike a proper chemistry lab in our School of Chemistry, I always have to figure out some crude ways to fix stuff.ChemGradhttps://www.blogger.com/profile/18304732744053614163noreply@blogger.comtag:blogger.com,1999:blog-7726130056398324774.post-56825723123779118452010-05-09T10:05:15.067+10:002010-05-09T10:05:15.067+10:00Rotary Valves:
http://www.princeton.edu/~mjsouza/s...Rotary Valves:<br />http://www.princeton.edu/~mjsouza/schlenk.jpg<br /><br />or<br /><br />Glass taps<br />http://farm1.static.flickr.com/31/52428338_94344e86ca.jpgLabchimphttps://www.blogger.com/profile/01132553734893580232noreply@blogger.comtag:blogger.com,1999:blog-7726130056398324774.post-53254353948744505912010-05-09T09:54:09.656+10:002010-05-09T09:54:09.656+10:00Did u have the system connected through your manif...Did u have the system connected through your manifold via a hose attached to this piece of glassware?: <br />http://www.ctechglass.com/images/AD-0013-001b.jpg<br />under inert gas so the hydrogen gas could escape? Otherwise u have constructed a rather dangerous closed system that will relieve the pressure at some stage<br />With respect to your manifold problem im thinking u have Young's type adapters similar to the ones in this photo?<br />http://www.princeton.edu/~polymer/vacuumline.jpgLabchimphttps://www.blogger.com/profile/01132553734893580232noreply@blogger.comtag:blogger.com,1999:blog-7726130056398324774.post-18999537438247981472010-05-08T22:32:39.341+10:002010-05-08T22:32:39.341+10:00I dried ACN over pottasium carbonate for 24hr, the...I dried ACN over pottasium carbonate for 24hr, then molecular sieve for 24hr and distilled with CaH2 (where the problem arose with build up pressure due to gas formation, H2).ChemGradhttps://www.blogger.com/profile/18304732744053614163noreply@blogger.comtag:blogger.com,1999:blog-7726130056398324774.post-85085820920292714822010-05-08T22:26:55.471+10:002010-05-08T22:26:55.471+10:00its plastic screw cap.. not glass stopcock. Sorry ...its plastic screw cap.. not glass stopcock. Sorry for the misinformation.<br /><br />How do I purify ACN? I tried distill off with CaH2 and it produced too much gas, build up pressure and push my distillation thermometer. I'm afraid I did not distill this solvent properly at the end ie still wet. Any suggestion?ChemGradhttps://www.blogger.com/profile/18304732744053614163noreply@blogger.comtag:blogger.com,1999:blog-7726130056398324774.post-68187731748816723472010-05-02T10:29:09.776+10:002010-05-02T10:29:09.776+10:00I think you would be better off buying a new screw...I think you would be better off buying a new screw end. If I read the post correctly you are talkin about the screw cap part not the stopcock itself. I would just take it to a glassblower and they will give you a new one (so much faster than gluing it.OrganicOverdosehttps://www.blogger.com/profile/06308937714718821761noreply@blogger.comtag:blogger.com,1999:blog-7726130056398324774.post-34890009231681722802010-04-30T18:26:23.401+10:002010-04-30T18:26:23.401+10:00YAY!! (to the solvents purification procedures)
I...YAY!! (to the solvents purification procedures)<br /><br />I have a problem with the manifold. One of the plastic or silicon screw stopcock (aid the opening and closing of the line) is ruined. Anyone knows how to fix this? What kind of super glue would work?ChemGradhttps://www.blogger.com/profile/18304732744053614163noreply@blogger.com