00rich Posted November 28, 2011 Share Posted November 28, 2011 I am wondering generally how hot you can perform an evaporation of an organic substance dissolved in a solvent or other liquid. 1) Does one usually boil the liquid to evaporate it off or heat it only part of the way to boiling and wait? 2)Are there any tips/techniques anyone has for easy and efficient evaporation's? 3) I was assuming some substances will be altered by too much heat while trying to evaporate, is this a fair assumption? Link to comment Share on other sites More sharing options...
hypervalent_iodine Posted November 28, 2011 Share Posted November 28, 2011 It depends on your compound. Some will decompose at the temperatures required to distill them or the solvent they're in. Generally though, if you're just trying to remove solvents, rotary evaporators followed by high-vacuum pumps/lyophilizers are the way to go. They use reduced pressure to decrease the boiling point of the components in the mixture, allowing volatile substances to be removed fairly easily without the need for much heat. Link to comment Share on other sites More sharing options...
Horza2002 Posted November 28, 2011 Share Posted November 28, 2011 It really depends on what solvent your trying to remove as well. For example, if you are trying to remove water from a sample, it is much easier to freeze dry it (freeze the sample in liquid nitrogen and then allow it to sublime under a vacuum). If your trying to remove diethyl ether...you could just leave it in a warm room for a few hours and you'd be fine.....in a fumecupboard of course. Link to comment Share on other sites More sharing options...
00rich Posted November 28, 2011 Author Share Posted November 28, 2011 The boiling point of this particular substance is stated in the procedure to be 111-114 degrees celcius. The solution did boil at this temperature and evaporated very quickly. Near the end of the evaporation the color changed from light yellow to black (final dried product was also black) and i'm not sure if this is a sign that I raised the temperature too high or if it is supposed to be black (The procedure dosn't say anything about color) Link to comment Share on other sites More sharing options...
Horza2002 Posted November 29, 2011 Share Posted November 29, 2011 Without knowing what your compound is, it probably sounds like that your compound degraded. Link to comment Share on other sites More sharing options...
mississippichem Posted November 29, 2011 Share Posted November 29, 2011 The boiling point of this particular substance is stated in the procedure to be 111-114 degrees celcius. The solution did boil at this temperature and evaporated very quickly. Near the end of the evaporation the color changed from light yellow to black (final dried product was also black) and i'm not sure if this is a sign that I raised the temperature too high or if it is supposed to be black (The procedure dosn't say anything about color) Did the literature give a boiling point for your product, or for the solution you are trying to distill? If it just gave a boiling point for the compound and not your solution, then that's no good for the distillation and we can help you calculate or approximate the boiling point of your solution to be distilled. Link to comment Share on other sites More sharing options...
00rich Posted November 29, 2011 Author Share Posted November 29, 2011 The procdure says that you evaporate to give the product, and that the product has a BP of 111-114 degrees C (0.1 mm Hg). It also says that the product is very unstable and that it must be used right away and that attempts to further distill it at 0.1 mm Hg wil decompose it. This sounds like I would have to be very carefull when I am evaporating. Any tips? Link to comment Share on other sites More sharing options...
mississippichem Posted November 29, 2011 Share Posted November 29, 2011 (edited) The procdure says that you evaporate to give the product, and that the product has a BP of 111-114 degrees C (0.1 mm Hg). It also says that the product is very unstable and that it must be used right away and that attempts to further distill it at 0.1 mm Hg wil decompose it. This sounds like I would have to be very carefull when I am evaporating. Any tips? So the product is a liquid? Mind letting us know what the product is and what solvent it is in? If the product is a liquid then it should boil out at it's regular b.p. I made my last post with the assumption that you were trying to remove solvent from a solid solute. If your product is a liquid, my last post is moot. Edited November 29, 2011 by mississippichem Link to comment Share on other sites More sharing options...
00rich Posted November 29, 2011 Author Share Posted November 29, 2011 (edited) The product is 1-bromocyclopentyl-(o-chlorophenyl)-ketone. The solvent is CCl4. I am supposed to evaporate the bromo-ketone to obtain a solid. Edited November 30, 2011 by 00rich Link to comment Share on other sites More sharing options...
hypervalent_iodine Posted November 30, 2011 Share Posted November 30, 2011 And so now do you feel like telling us why you're making PCP derivatives? 2 Link to comment Share on other sites More sharing options...
CaptainPanic Posted November 30, 2011 Share Posted November 30, 2011 I suggest we don't respond anymore, while we await the response to hypervalent_iodine's question. Some derivative of a drug is not something you make as a hobby... and if you're in research of organic chemistry or working at a pharmaceuticals company (both valid reasons to work on this), then you shouldn't have to ask these kinds of questions on a forum on the internet. But there may be another valid reason that I hadn't thought of. Link to comment Share on other sites More sharing options...
00rich Posted November 30, 2011 Author Share Posted November 30, 2011 (edited) Our project is an investigation into the treatment of antidepression in bipolar individuals using specific PCP analogs. There are some derivatives which have shown very promising results. Racemic seperation has shown to be a route to take to try and remove the adverse effects (confusion, ataxia, sensory distorsion, etc) that have prevented these derivatives from wide spread use. We are currently conducting this research in Mexico to avoid any legal hangups. Since the racemic mixtures we want to test aren't readily available we have decided to do the synthesis ourselves. However, our organic chemistry abilities are a little rusty. I understand this maybe outside the rules of your forum and I will gladly refrain from posting anymore about this sincerly apologize for any trouble. Edited November 30, 2011 by 00rich Link to comment Share on other sites More sharing options...
hypervalent_iodine Posted November 30, 2011 Share Posted November 30, 2011 00rich, I am somewhat conflicted with how to respond to this. One the one hand, the fact that you have access to solvents like carbon-tet and the various other chemicals lends credibility to your claim that this is for research. On the other hand, I did in fact find what I am 99% sure is the source you are using for this synthesis and I am extremely confused as to why a research group would use this particular web site for any sort of synthetic protocol. One other thing that becomes glaringly obvious upon having read this synthesis is that (and I mean as little offense in this as possible) you have no clue what you are doing when it comes to reading and interpretting chemical methodology. So here is my solution for you. I am not comfortable tellig you what you've done wrong and how to fix it in this forum due to T&C's. If this is for research purposes and you are part a legitimate research group, something I am quite sure you do have access too is contacts and/or colleagues. Get a chemist in your department or building or where ever to come and help you. You have quite badly misread the methodology of your synthesis and synthetic chemistry is not something you should be playing with if you don't know what you are doing. I cannot stress that last part enough. 2 Link to comment Share on other sites More sharing options...
CaptainPanic Posted January 13, 2014 Share Posted January 13, 2014 ! Moderator Note This thread has been locked because the topic is (closely) related to the synthesis of illegal substances. Recently a member added a new post to this relatively old thread, which we subsequently removed. This is the reason for this 'update'. Unfortunately, we (mods) had failed to lock the thread before. We apologize that we left a thread open that should have been locked a long time ago. So, move along, move along... there's nothing to see here. Only this mod note is new. Link to comment Share on other sites More sharing options...
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