XrLeap
(Hive Bee) 09-10-04 12:44 No 530685 |
NaBH4 help needed | |||||||
Hi:) Good-day. SWIM has read some posts, particularly interested in this Post 439898 (LaBTop: "No. Wrong.", Newbee Forum)it stated ethanol and DMF are having good solubility of NaBH4. Has any bee tried out using ethanol or DMF as solvent? Can the methylamine gas be dissolved in these solvents easily? SWIM attempted many times IPA aka Barium's, yield was not as expected, SWIM thinks that he is not fated to use IPA and would like to switch to other solvent. Can any kind bee help to anwser this, thanks. oops i did it again |
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r2e3 (Hive Bee) 09-10-04 16:47 No 530714 |
see | |||||||
rhodium's borohydride work up it works. methanol is best. if you can get the other solvents, MeOH should be the least of your worries |
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XrLeap (Hive Bee) 09-11-04 12:57 No 530909 |
Hi r2e3, Thanks for the reply. | |||||||
Hi r2e3, Thanks for the reply. SWIM reads in this thread, Post 439864 (Vibrating_Lights: "Imine reduction", Newbee Forum)Ethanol has got reasonable NaBH4 solubility, 4g/100g. At room temperature. SWIM also reads in some thread that ethanol can hold 33% wt of methylamine. Does it call for a good solvent for NaBH4 reduction? SWIM thinks the only disadvantage is the price over Methanol. But it has the advantage of doing the reaction under Room Temperature, greater absorbtion of Methylamine freebase too. SWIM faced some problems during gassing of methylamine into iced cold methanol. Keeping the methanol cold, preventing suckback, implosion, even made mistakes like flask filled accidentally with water from the ice bath..... from the thread:
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LaBTop (Daddy) 09-11-04 16:34 No 530934 |
Ahh, the memories! | |||||||
That last link brings back good vibrations to me. In that thread, there's so much hidden value, it still flabbergasts me that the combined potential of our members haven't jumped on the possibilities outlined all over the thread. Especially the quaternary Boro ones, and the added PTC ones, I haven't noticed. Or did I miss it? (Yes, I know of Bariums advice for use of Aliquat with his wet method) Do we have a shitload of duplicated results a la Barium's wet method yet, or not? I ask this, because you seemed not to have found them, and declare that you tried it multiple times with IPA as the solvent, with ?low? yields. LT/ WISDOMwillWIN |
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XrLeap (Hive Bee) 09-11-04 21:57 No 530909 |
Hi r2e3, Thanks for the reply. | |||||||
Hi r2e3, Thanks for the reply. SWIM reads in this thread, Post 439864 (Vibrating_Lights: "Imine reduction", Newbee Forum)Ethanol has got reasonable NaBH4 solubility, 4g/100g. At room temperature. SWIM also reads in some thread that ethanol can hold 33% wt of methylamine. Does it call for a good solvent for NaBH4 reduction? SWIM thinks the only disadvantage is the price over Methanol. But it has the advantage of doing the reaction under Room Temperature, greater absorbtion of Methylamine freebase too. SWIM faced some problems during gassing of methylamine into iced cold methanol. Keeping the methanol cold, preventing suckback, implosion, even made mistakes like flask filled accidentally with water from the ice bath..... from the thread:
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LaBTop (Daddy) 09-12-04 01:34 No 530934 |
Ahh, the memories! | |||||||
That last link brings back good vibrations to me. In that thread, there's so much hidden value, it still flabbergasts me that the combined potential of our members haven't jumped on the possibilities outlined all over the thread. Especially the quaternary Boro ones, and the added PTC ones, I haven't noticed. Or did I miss it? (Yes, I know of Bariums advice for use of Aliquat with his wet method) Do we have a shitload of duplicated results a la Barium's wet method yet, or not? I ask this, because you seemed not to have found them, and declare that you tried it multiple times with IPA as the solvent, with ?low? yields. LT/ WISDOMwillWIN |
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XrLeap (Hive Bee) 09-16-04 16:07 No 531608 |
Thanks for the reply | |||||||
Thanks, Sir LabTop, for the reply. SWIM had read through your boro in one pot thread, summed up to 109 posts. You sure have helped a lot of bees ' life easier. Allow me to say thank you, Sir.[bow] SWIM's best result is about 40%(lowest was 0%) m/m using IPA(91% purity, 99% gave lower yield), SWIM believes it is due to his technique. Wether forming of amine was the cause or any other thing, SWIM always has a lot of mdp2pol as main product. If mdp2pol is good, SWIM has alreadly found out the way to have good yield. SWIM tried to remove water from IPA after generating of methylamine gas(methylamine.HCL solution mixed with NaOH solution, aka Barium's), by seperation. The stirring was allowed for 2 hours before seperation. Added NaBH4 solution(in water) to the IPA, and gave about 15% yield. But one thing SWIM finds out, is the product(salt) is very good from IPA as solvent, there is no scienctific proof for this but was tested(blind test) with some other human objects. SWIM is tyring to find out ethanol's possibility as solvent. As there is chem supplier selling it "Methylamine, 33% wt in absolute Ethanol". SWIM has read it somewhere about using ethanol, but no details described. There is one post saying that Methanol is the solvent when using Methylamine, Ethanol is the choice when Ethylamine is used. Is this true? oops i did it again |
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LaBTop (Daddy) 09-18-04 15:08 No 531976 |
Huh? | |||||||
It's told by me ad infinitum, that waterfree Methanol is the premium choice to use in a one pot boro procedure. So I suppose you are talking about Bariums wet procedure. But why you are attempting to dry the IPA then, is unclear to me. PM Barium with a precise explanation what exactly you did, otherwise you won't get a response. Endproducts, if recristalized 1 or 2 times, are all the same quality, doesn't matter which procedure is used, so your previous bioassays must have been from shitty, hurried cooks. Trying to remove water from IPA by separation is just plain funny, that will never succeed. Use mol sieves or oven-dried silicagel. LT/ EDIT: I see you already got help from a PM: Post 531792 (XrLeap: "Easy NaBH4 amination", Newbee Forum) WISDOMwillWIN |
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XrLeap (Hive Bee) 09-18-04 17:33 No 531997 |
Hi Sir LabTop, Thanks for the reply. | |||||||
Hi Sir LabTop, Thanks for the reply. SWIM just typed a long post and accidentally pressed ctrl+w and closed the window.... SWIM attempted The Archetypical "Good Guy", Bandil's method. Post 503533 (Bandil: "Pseudo-"wet"- BH4 amination BH4", Methods Discourse)It stated 80%+ of yield is achievable. However, SWIM used Barium's method to generate methylamine gas in situ, whereas Bandil used 40% aq methylamine solution. The IPA as solvent method is quite sentive to the parameters, and end yield will be affected badly. Side note, when water is very salty, it forms 2 layers with IPA. Most of the low yield was more or less due to SWIM's sloppy nature, that is also why SWIM is not generating methylamine gas to "pump" them into methanol. SWIM is trying to explore the possibilities of using DMF and Ethanol as solvent. DMF is dipolar aprotic solvent, several things needed to find out/explore, solubility of NaBH4, solubility of methylamine.hcl, capacity of holding methylamine freebase. SWIM believe DMF fume is relatively safer than methanol's. For ethanol, it is commercially available with methylamine dissolved. Easy preparation. SWIM will report back his findings, but not too soon as he has only 1 day to work on his hobby in a week. oops i did it again |
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Sedrick 09-19-04 20:23 |
A guy I know from the Democratic of Congo...
(Rated as: insignificant) |
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