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joe_aldehyde
huxleys associate
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| Joined: 06 Apr 2005 |
| Posts: 310 |
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5653.90 Points
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re: phenyl-2-nitropropene recrystallization issues
Thu May 26, 2005 3:56 pm |
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98% AA is 98% AA. GAA is 100% AA. thats what my respective merck bottles say. besides that, STFU, please! i've had enough of your rantings. your bigheaded attitude is of little use here. yes, i've seen the ref. by barium and i'm gonna use it. why don't YOU go waste your time in the lab and do something useful instead. or go do a little writeup about your mercurophobia which you can post and then lock the thread. i'm sorry to say that all your "safety warnings" are of little concern in the threads you've posted, there is a separate section for chemical safety instructions.
and now please do me the favor and refrain from posting in MY threads and let people talk that understand what my questions are about. |
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IndoleAmine
Dreamreader Deluxe
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| Joined: 09 Feb 2005 |
| Posts: 681 |
| Location: Bahamas |
18717.10 Points
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: phenyl-2-nitropropene recrystallization issues
Thu May 26, 2005 4:17 pm |
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ts, ts - will you stay civil now??
If you know about the possibility of using aequous methylamine, stop cloggin up our webspace with therefore redundant questions about if you can use it - m'kay!?....
GAA is 98-100% acetic acid according to several old and new merck, Acros, riedel/deHaen, SigmaAldrich and even "Reachim" bottles I#ve got lying around, if that is of importance to you.
Of more importance to you might be the fact that AA is commonly considered either acetic anhydride or ammonium acetate, but fer sure not acetic acid...  
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i've had enough of your rantings. your bigheaded attitude is of little use here. yes, i've seen the ref. by barium and i'm gonna use it. why don't YOU go waste your time in the lab and do something useful instead. or go do a little writeup about your mercurophobia which you can post and then lock the thread. i'm sorry to say that all your "safety warnings" are of little concern in the threads you've posted, there is a separate section for chemical safety instructions.
and now please do me the favor and refrain from posting in MY threads and let people talk that understand what my questions are about.
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Then I guess its time for you to think about srious consequences for me - right? 
(...)
I don't care which problems you have with the fact that I post here, and I doubt that others would refrain from doing so because I did too.
You do know the meaning of the words "keep it civil", do you?
Then do so, and please read the board rules.
i_a |
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Star-light
Blacklight bulb
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| Joined: 26 Mar 2005 |
| Posts: 77 |
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2681.50 Points
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Re: re: phenyl-2-nitropropene recrystallization issues
Thu May 26, 2005 5:06 pm |
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| joe_aldehyde wrote: |
yes i can do TLC, what solvent system do you suggest?
can i also drop methylamine aq.40% and GAA together with MeOH in the flask? i wonder if the water already present is likely to pose problems. or can i just neutralize aq. methylamine with GAA or plain 98% AA and then evaporate the water?
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Aqueous methylamine can indeed be used, but the less water you have in the system, the better are the yields and the lower the byproducts. I discussed Barium's results with him and he agreed that if possible, it is better to use a solution of methylamine acetate in Methanol with as little water present as possible. |
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IndoleAmine
Dreamreader Deluxe
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| Joined: 09 Feb 2005 |
| Posts: 681 |
| Location: Bahamas |
18717.10 Points
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: phenyl-2-nitropropene recrystallization issues
Thu May 26, 2005 5:20 pm |
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oh - how this differs in information content from my unwanted effort to help....
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I discussed Barium's results with him and he agreed that if possible, it is better to use a solution of methylamine acetate in Methanol with as little water present as possible.
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Do you have a ref for that? Barium explicitly mentioned having shown that the H2O wouldn't be detrimental, at least he wrote so - thats why I'm asking for a ref...
(and I would LOVE to see the efforts of "evaporating water" from wet methylammonium acetate- its hygroscopic as hell and evapping won't work. But this info is merely thought for everyone who might read this thread though not being the author of it - so NOT for joe_dehyde..) |
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joe_aldehyde
huxleys associate
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| Joined: 06 Apr 2005 |
| Posts: 310 |
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5653.90 Points
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re: phenyl-2-nitropropene recrystallization issues
Thu May 26, 2005 5:41 pm |
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star-light: regarding your discussion with barium, i want to point out the following: even if the equilibrium is pushed to the right when removing or excluding water, the bad solubility of the educts and products in water show that the very presence of water might not have a detrimental effect. that's especially true when looking at various posts stating that one has to wash p2np with WATER after the reaction. if hydrolysis occured at all, it might not be at a great rate.
i'm currently thinking of employing a PTC in the ultrasound reaction. what's your opinion, might help a bit? |
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IndoleAmine
Dreamreader Deluxe
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| Joined: 09 Feb 2005 |
| Posts: 681 |
| Location: Bahamas |
18717.10 Points
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: phenyl-2-nitropropene recrystallization issues
Thu May 26, 2005 5:47 pm |
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Yay sure, water in the rxn is the same as water on the end product....
Besides, why do you need HELP when pouring a PTC into an ultrasound bath for a knoevenagel (or henry) condensation with plain BENZALDEHYDE??
Can't you mess up this simple rxn by yourself by doing what you plan to do?  |
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Star-light
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| Joined: 26 Mar 2005 |
| Posts: 77 |
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2681.50 Points
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Re: : phenyl-2-nitropropene recrystallization issues
Fri May 27, 2005 12:09 am |
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| IndoleAmine wrote: |
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Do you have a ref for that? Barium explicitly mentioned having shown that the H2O wouldn't be detrimental, at least he wrote so - thats why I'm asking for a ref...
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How am I supposed to have a reference for a private discussion?
If you mean do I have evidence, then yes I do. Many trials have indicated that a methanolic methylamine acetate condensation is far more reliable than aqueous methylamine at producing a pure product at the high yields that Barium achieved. If Barium were here (which he never will be I'm sure) then he would agree that less water in the system leads to a cleaner reaction across a range of aldehydic substrates.
Given that this has been my Knoevenagel catalyst of choice then I would say that I have a fair degree of experience with how to get the best out of the system.
| joe_aldehyde wrote: |
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i want to point out the following: even if the equilibrium is pushed to the right when removing or excluding water, the bad solubility of the educts and products in water show that the very presence of water might not have a detrimental effect. that's especially true when looking at various posts stating that one has to wash p2np with WATER after the reaction. if hydrolysis occured at all, it might not be at a great rate.
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Joe, I'm only talking about what has been found empirically. As to why, I'm afraid that I'm not a good enough chemist to tell you why.
I can't see a PTC helping in the ultrasound knoevenagel as apart from the water which you want to keep out of the reaction, you only have one phase to consider. I could really only see a PTC making things worse. |
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joe_aldehyde
huxleys associate
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| Joined: 06 Apr 2005 |
| Posts: 310 |
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5653.90 Points
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re: phenyl-2-nitropropene recrystallization issues
Fri May 27, 2005 12:16 am |
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| ok then. i just happen to only have methylamine aqueous solution here...is the acetate very hygroscopic? i'd just try to neutralize the solution with acetic acid and rotavap the shit out of it. |
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Star-light
Blacklight bulb
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| Joined: 26 Mar 2005 |
| Posts: 77 |
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2681.50 Points
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Re: re: phenyl-2-nitropropene recrystallization issues
Fri May 27, 2005 12:30 am |
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| joe_aldehyde wrote: |
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ok then. i just happen to only have methylamine aqueous solution here...is the acetate very hygroscopic? i'd just try to neutralize the solution with acetic acid and rotavap the shit out of it.
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I_A is right, the acetate is extremely hygroscopic.
I have no personal experience in the area of preparing it from aqueous methylamine (as methylamine hydrochloride is available), but if anything were going to work then forming the salt followed by removal of the water under vacuum / vacuum dessication may. |
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IndoleAmine
Dreamreader Deluxe
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| Joined: 09 Feb 2005 |
| Posts: 681 |
| Location: Bahamas |
18717.10 Points
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: phenyl-2-nitropropene recrystallization issues
Fri May 27, 2005 1:59 am |
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It may or may not. I#ve done it, but since you prefer staying stupid I will remain calm. At least about how to make methylammonium acetate. Much luck, hehe...
So you imply that methylamine.hcl would work as knoevenagel catalyst, or why do you say that stuff about the HCl salt??
And lo and behold, "I was right" - Shit. Now I gonna post heaps of nonsense for weeks, to catch up with you. Probably. (my fault, won't happen again... Since I'm not in my respective thread, I'm no mod here and hence my presence is FOR VACATION PURPOSES only - grrrrrr....  )
You huys are just neat, flaming me over and over and then bein not able to condense BENZALDEHYDE and NITROETHANE (hell it was the first rxn ever I attempted IIRC and with moderate but successful yield...)
Remember to come home for lunch boys. And wash your hands - m'kay?
oh, and another lil' teaser (just like you love to tease me): "Given that this has been my Knoevenagel catalyst of choice then I would say that I have a fair degree of experience with how to get the best out of the system." Oh you mean you are experienced? Whatta ref, I'm impressed.
Besides poor choice of catalyst, seen both cost- and workwise and with respect to this dirt-cheap go-go precursor reagent's price. Besides...
i_a  |
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Sandmeyer
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| Joined: 25 Mar 2005 |
| Posts: 39 |
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203.32 Points
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Re: : phenyl-2-nitropropene recrystallization issues
Fri May 27, 2005 3:05 am |
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If you mean do I have evidence, then yes I do. Many trials have indicated that a methanolic methylamine acetate condensation is far more reliable than aqueous methylamine at producing a pure product at the high yields that Barium achieved. If Barium were here (which he never will be I'm sure) then he would agree that less water in the system leads to a cleaner reaction across a range of aldehydic substrates.
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Which is quite logical, even if one would not have the insight in mechanism this could still be a rasonable conclusion as when sodium hydroxide is used as a base (the classical way to do it) you need a dean-stark trap or some other mean to remove the water, hence it can't be good in this reaction. |
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joe_aldehyde
huxleys associate
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| Joined: 06 Apr 2005 |
| Posts: 310 |
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5653.90 Points
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re: phenyl-2-nitropropene recrystallization issues
Fri May 27, 2005 3:22 am |
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we all know the mechanism, don't we  basic organic chemistry.
i guess the point in the reaction where water comes into play is the beta-elimination step from the nitroalkanol, which readily occurs.
btw. what is the named reaction that triggers when you add a mineral acid to the nitropropene?
oh yeah boys will you please not refer to any of i_a's statements anymore, because he will then shut up as he is a very wise and famous chemist who prefers to keep his "wisdom" to himself. i guess he may have smoked to much NaOH with his DMT. i once did pure NaOH in a crack pipe and it gave me a really nice buzz, but i wouldn't exactly label it an entactogen. it's more like...lettuce
Last edited by joe_aldehyde on Fri May 27, 2005 3:29 am; edited 1 time in total |
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Star-light
Blacklight bulb
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| Joined: 26 Mar 2005 |
| Posts: 77 |
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2681.50 Points
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Re: : phenyl-2-nitropropene recrystallization issues
Fri May 27, 2005 3:25 am |
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| IndoleAmine wrote: |
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So you imply that methylamine.hcl would work as knoevenagel catalyst, or why do you say that stuff about the HCl salt??
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Simply because if you have methylamine.hcl, then you can make a methanolic solution of methylamine acetate without a great deal of water in it as I posted here:
. But then again that was a few posts back in the thread so I can understand how you have failed to make the connection.
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Oh you mean you are experienced? Whatta ref, I'm impressed.
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If is experience is of no value to you, then I can see why you don't really know that much.
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Besides poor choice of catalyst, seen both cost- and workwise and with respect to this dirt-cheap go-go precursor reagent's price. Besides...
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The catalyst is good across a large range of substrates. The work is quick and easy unless you are retarded or inexperienced. In addition, in many parts of the world, bees find that they wish to make the most of limited supplies of nitroethane.
You are arguing for the sake of it and I can see you are already progressing as fast as you can in living up to your promise:
| IndoleAmine wrote: |
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And lo and behold, "I was right" - Shit. Now I gonna post heaps of nonsense for weeks
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IndoleAmine
Dreamreader Deluxe
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| Joined: 09 Feb 2005 |
| Posts: 681 |
| Location: Bahamas |
18717.10 Points
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: phenyl-2-nitropropene recrystallization issues
Fri May 27, 2005 4:09 pm |
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Simply because if you have methylamine.hcl, then you can make a methanolic solution of methylamine acetate without a great deal of water in it
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Again I'm impressed; but I would bet many bees can do the same without isolating/buying any methylamine.HCl......
About the ref issue: hey - ease up! It was you in the first time who requested other refs for statements, besides experience - IIRC.
heads up, at least you deserve pity.
(nitroethane is OTC bubba! Eyez up I suggest..... ) |
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Star-light
Blacklight bulb
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| Joined: 26 Mar 2005 |
| Posts: 77 |
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2681.50 Points
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Re: : phenyl-2-nitropropene recrystallization issues
Fri May 27, 2005 4:48 pm |
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| IndoleAmine wrote: |
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Again I'm impressed; but I would bet many bees can do the same without isolating/buying any methylamine.HCl......
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There are obviously many routes to achieving the same objective.
| IndoleAmine wrote: |
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About the ref issue: hey - ease up! It was you in the first time who requested other refs for statements, besides experience - IIRC.
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No, I requested evidence rather than speculation. I have never asked you for a ref.
| IndoleAmine wrote: |
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heads up, at least you deserve pity.
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What??!!
| IndoleAmine wrote: |
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(nitroethane is OTC bubba! Eyez up I suggest..... )
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Well that all depends upon where you come from. As you are well aware, it is difficult to get hold of in some countries (not where I am thankfully). The synthetic procedures to make it from OTC chemicals are also low yielding and laborious. I wish you would stop trying to show how clever you are. It just has the opposite effect. |
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