Author Topic: Methylamine - better yields - Rhodium  (Read 1656 times)

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Methylamine - better yields - Rhodium
« on: April 12, 2000, 02:32:00 AM »
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   Author        Topic:   Methylamine - better yields

   Rhodium       [Image] posted 05-11-98 05:24 AM
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                 --------------------------------------------------------

                 70 grams hexamethylenetetramine (0.5 mole) and 30 grams
                 paraformaldehyde (1 mole) was dissolved in 200 ml water
                 and 200ml 37% HCl (2 moles) was added. The mixture was
                 slowly heated and the contents was slowly distilled,
                 and the temperature rose slowly over 1-2 hours to
                 109_C. During this time, a lot of CO2 was evolved, and
                 approx 75ml of formaldehyde-smelling distillate was
                 collected. The solution was concentrated under vacuum
                 until a lot of solids precipitated, which were filtered
                 off, and the solution was further concentrated,
                 filtered etc until everything was crystallized. The
                 white solids were placed in 150ml warm MeOH, and
                 filtered. The insoluble portion was recrystallized from
                 water, to give XX grams of ammonium chloride. The
                 methanol solution was evaporated and recrystallized
                 from methanol and washed with acetone, to give a
                 deliquescent crystalline mass, which was dried in a
                 desiccator over CaCl2, to give 49 grams of methylamine
                 hydrochloride (0.72 mole). Calculated on the two moles
                 of amine nitrogen put into the equation, 36% became
                 methylamine, and 37% (0.75 mole) became ammonium
                 chloride. The net yield of methylamine is therefore
                 58%.

                 (No, I'm out of chloroform. Can any other solvent
                 substitute for it when washing away dimethylamine?)

   quirks        [Image] posted 05-11-98 10:28 AM
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                 --------------------------------------------------------
                 Why not TCE?? It has similar solvent charecteristics
                 no? That's what I was going to use instead of
                 chloroform.

   quirks        [Image] posted 05-11-98 10:28 AM
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                 Why not TCE?? It has similar solvent charecteristics
                 no? That's what I was going to use instead of
                 chloroform.

   David         [Image] posted 05-11-98 02:54 PM
   unregistered
                 --------------------------------------------------------
                 Rodium, does this method seem to be easier/cheaper/less
                 work than the NH3 + formaldehyde one? I mean, since you
                 gotta use NH3 and formaldehyde to make
                 hexamethylenetetramine anyway. (unless you want to buy
                 it)

   David         [Image] posted 05-11-98 02:54 PM
   unregistered
                 --------------------------------------------------------
                 Rodium, does this method seem to be easier/cheaper/less
                 work than the NH3 + formaldehyde one? I mean, since you
                 gotta use NH3 and formaldehyde to make
                 hexamethylenetetramine anyway. (unless you want to buy
                 it)

   Rhodium       [Image] posted 05-11-98 04:04 PM
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                 --------------------------------------------------------
                 I just had all the chemicals lyin' around and I *WILL*
                 convert Hexamine to methylamine! I will I will I will!
                 

                 As it stands, the method sucks, but at least I managed
                 to get a decent yield of methylamine from hexamine
                 after all. But it is far from quantitative yield. I
                 must find those articles in Bull Soc Chim and Compt
                 Rend...

   Rhodium       [Image] posted 05-11-98 04:04 PM
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                 --------------------------------------------------------
                 I just had all the chemicals lyin' around and I *WILL*
                 convert Hexamine to methylamine! I will I will I will!
                 

                 As it stands, the method sucks, but at least I managed
                 to get a decent yield of methylamine from hexamine
                 after all. But it is far from quantitative yield. I
                 must find those articles in Bull Soc Chim and Compt
                 Rend...

   Semtex Enigma [Image] posted 05-11-98 06:33 PM
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                 I take it you had made your own or were using reagent
                 grade Hex, right? Have you had any success using the
                 Camping fuel tabs? I haven't been able to SUCCESSFULLY
                 remove all that other crap from those tablets... do ya
                 have a procedure to do such a thing? I still plan on
                 making my own hex once or twice to get the practice,
                 but I wouldn't mind having 5-10kg methylamine in a
                 cache in the hills or somethin....

   Semtex Enigma [Image] posted 05-11-98 06:33 PM
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                 --------------------------------------------------------
                 I take it you had made your own or were using reagent
                 grade Hex, right? Have you had any success using the
                 Camping fuel tabs? I haven't been able to SUCCESSFULLY
                 remove all that other crap from those tablets... do ya
                 have a procedure to do such a thing? I still plan on
                 making my own hex once or twice to get the practice,
                 but I wouldn't mind having 5-10kg methylamine in a
                 cache in the hills or somethin....

   Rhodium       [Image] posted 05-11-98 07:49 PM
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                 --------------------------------------------------------
                 I use reagent grade hexamine, yes. And as I am not
                 american, I don't know how to purify your camping fuel.
                 Our european brand "Esbit" is easily purified by
                 recrystallization from water.

   Rhodium       [Image] posted 05-11-98 07:49 PM
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                 --------------------------------------------------------
                 I use reagent grade hexamine, yes. And as I am not
                 american, I don't know how to purify your camping fuel.
                 Our european brand "Esbit" is easily purified by
                 recrystallization from water.

   Semtex Enigma [Image] posted 05-12-98 01:02 AM
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                 Do you mean disolve tablet(s) in water filter and save
                 (1) Liquid or (2) Soild? I would think that if it is
                 the liquid that needs to be saved, the water would have
                 to be evaporated, no?

   Semtex Enigma [Image] posted 05-12-98 01:02 AM
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                 --------------------------------------------------------
                 Do you mean disolve tablet(s) in water filter and save
                 (1) Liquid or (2) Soild? I would think that if it is
                 the liquid that needs to be saved, the water would have
                 to be evaporated, no?

   Rhodium       [Image] posted 05-12-98 07:11 AM
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                 --------------------------------------------------------
                 Yes, throw away solid, evaporate water. It would be
                 simpler to use CHCl3, but it may dissolve the binder
                 too.

   Rhodium       [Image] posted 05-12-98 07:11 AM
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                 Yes, throw away solid, evaporate water. It would be
                 simpler to use CHCl3, but it may dissolve the binder
                 too.

   adamantane    [Image] posted 05-14-98 03:19 AM
   unregistered
                 --------------------------------------------------------
                 You know, maybe the laws of physics are weird here in
                 Kansas, but the other night Dorothy was whisked to a
                 land where she made Methylamine from Hexamine campfuel
                 tablets with near 100% yield in a very short perios of
                 time, following the proportions that are listed, uh,
                 somewhere? Maybe on Rhodium's page? In any case, it's
                 140g hexamine/400mL HCl/100mL ethanol. HOwever the
                 following modifications were made:

                 1. scale down factor of 4 (35g hexamine)
                 2. subst. 99% isopropanol (avail at the drugstore, if
                 it's a good one)
                 3. Procedure was as follows:

                 Pour HCl into bowl. Add Isopropanol with stirring. Add
                 hexamine in portions with stirring. Heat and CO2 are
                 released. As soon as all solids are dissolved* boil the
                 hell out of it to drive off water, HCl, etc. Result is
                 fast and easy and beautiful.

                 *This is a modification from the posted journal
                 procedure, which said to let it sit 8-16 hours. Dorothy
                 found that letting it stand _decreased_ yield and
                 increased formation of the white fluffy precipitate
                 which is almost certainly ammonium chloride.

                 Soon I will have the results of various analyses of the
                 product to see how pure it is. However it seems likely
                 that the only possible contaminant is dimethylamine,
                 and there can only be a minority of that, even in the
                 worse circumstances, because each hexamine molecule has
                 only 6 C's to 4 N's...

                 Anybody else feel like they might get picked up by a
                 tornado and sent to a place where they can try to
                 duplicate Dorothy's dream?

   adamantane    [Image] posted 05-14-98 03:19 AM
   unregistered
                 --------------------------------------------------------
                 You know, maybe the laws of physics are weird here in
                 Kansas, but the other night Dorothy was whisked to a
                 land where she made Methylamine from Hexamine campfuel
                 tablets with near 100% yield in a very short perios of
                 time, following the proportions that are listed, uh,
                 somewhere? Maybe on Rhodium's page? In any case, it's
                 140g hexamine/400mL HCl/100mL ethanol. HOwever the
                 following modifications were made:

                 1. scale down factor of 4 (35g hexamine)
                 2. subst. 99% isopropanol (avail at the drugstore, if
                 it's a good one)
                 3. Procedure was as follows:

                 Pour HCl into bowl. Add Isopropanol with stirring. Add
                 hexamine in portions with stirring. Heat and CO2 are
                 released. As soon as all solids are dissolved* boil the
                 hell out of it to drive off water, HCl, etc. Result is
                 fast and easy and beautiful.

                 *This is a modification from the posted journal
                 procedure, which said to let it sit 8-16 hours. Dorothy
                 found that letting it stand _decreased_ yield and
                 increased formation of the white fluffy precipitate
                 which is almost certainly ammonium chloride.

                 Soon I will have the results of various analyses of the
                 product to see how pure it is. However it seems likely
                 that the only possible contaminant is dimethylamine,
                 and there can only be a minority of that, even in the
                 worse circumstances, because each hexamine molecule has
                 only 6 C's to 4 N's...

                 Anybody else feel like they might get picked up by a
                 tornado and sent to a place where they can try to
                 duplicate Dorothy's dream?

   RatHead       [Image] posted 05-14-98 08:15 AM
   unregistered
                 --------------------------------------------------------
                 The possibilties of some 2 carbon skeleton degradation
                 products exist also. I'm trying to find that info on
                 the hexamine degradation mechanism.

   RatHead       [Image] posted 05-14-98 08:15 AM
   unregistered
                 --------------------------------------------------------
                 The possibilties of some 2 carbon skeleton degradation
                 products exist also. I'm trying to find that info on
                 the hexamine degradation mechanism.

   Labrat        [Image] posted 05-14-98 09:59 AM
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                 --------------------------------------------------------
                 Adamantane, what if I told you that adding an alcohol
                 to the reaction mix with hexamine will lower the yield
                 of methylamine? But I ain't bullshittin' you! Just
                 check out the article Werner wrote in the JCS ('18).
                 Here the author states, that a low yield is bound to be
                 had from formalin and ammonium chloride, since formalin
                 contains methanol as an polymerisation inhibitor.
                 Formaldehyde will react with methanol at a temp of
                 about 40-50 dg C forming methylal and thus lowering
                 overall yield. Substituting isopropanol will only make
                 the acetal-forming easier. Now you see why you
                 shouldn't mix alcohol in the Hex->Mex reaction?

   Labrat        [Image] posted 05-14-98 09:59 AM
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                 --------------------------------------------------------
                 Adamantane, what if I told you that adding an alcohol
                 to the reaction mix with hexamine will lower the yield
                 of methylamine? But I ain't bullshittin' you! Just
                 check out the article Werner wrote in the JCS ('18).
                 Here the author states, that a low yield is bound to be
                 had from formalin and ammonium chloride, since formalin
                 contains methanol as an polymerisation inhibitor.
                 Formaldehyde will react with methanol at a temp of
                 about 40-50 dg C forming methylal and thus lowering
                 overall yield. Substituting isopropanol will only make
                 the acetal-forming easier. Now you see why you
                 shouldn't mix alcohol in the Hex->Mex reaction?

   green_pea     [Image] posted 02-08-99 01:59 PM
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                 --------------------------------------------------------
                 Back to the original question Rhod asked about---what
                 is another substitute for chloroform. If one were doing
                 the Formaldehyde/ammon. chlor. rxn for methylamine--is
                 there another substitute for chloroform maybe DCM????
                 Anyone??

   The Cook      [Image] posted 02-10-99 03:38 AM
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                 --------------------------------------------------------
                 Oh Rhodium, you are the sickest.
                 Yep, paraform would definately make this rxn a molar
                 assload more repeatable.....
                 I think ppl's problems are the TYPE of hexamine they
                 use. Military (US) is fine, can be dissolved/filtered
                 with acetone. But watch out, I got some "hexamine" that
                 obviously wasn't. (It was trioxane, a.k.a
                 paraformaldehyde-useful, but deceptive)
                 Actually, Military trioxane bars (clean out the purple
                 w/ acetone, scrape off the clear igniter crap first)
                 are good for your formaldehyde needs....
                 Yeah, so I'm saying you're both right... I never
                 understood why people think Methlyamine is
                 restricted.....
                 -cook

   ChemHack      [Image] posted 02-10-99 12:28 PM
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                 --------------------------------------------------------
                 Here in the US, methylamine and its salts are
                 restricted.

                 In my opinion, the reason that Rhodium got higher
                 yields when adding paraformaldehyde is that there is
                 excess ammonium chloride formed when the hexamine
                 breaks down. The paraform reacts with this extra NH4Cl.

                 Of course, I could be wrong.
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