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Mr Cool
June 8th, 2003, 01:11 PM
I was just gathering some stuff on forming salts of methylamine earlier, and thought that since I had this lovelly little nugget of information, I'd post it here, in case anyone was interested.
Taken from patents and the Hive/Rhodium's site.

(Mono)methylamine Nitrate.
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NH4NO3 + 2 CH2O --> CH3NH3NO3 + HCOOH,
NH4NO3 + CH2O + HCOOH --> CH3NH3NO3 + H2O + CO2
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800g of a 37% by weight aqueous formaldehyde solution were mixed with 48g of urea and to the resulting mixture were added 800g of solid ammonium nitrate. On warming the mixture to 60*C, an exothermic reaction set in and the temperature rose to 90-95*C. The reaction mixture was maintained at a temperature of 95-100*C by applying heat when necessary for a period of 3 to 4 hours.Considerable quantities of carbon dioxide were released and at the end of the reaction period the reaction mixture had the following composition:
Solids : 67%
Formic acid : 1%
Water : 32%
The reaction mixture so formed, containing unreacted ammonium nitrate and methylamine nitrate, can be evaporated in any suitable evaporation system to a water content that is desired in the final explosive.
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A mixture of 800 parts by weight of ammonium nitrate, 620 parts by weight of 37% commercial grade formaldehyde and 50 parts by weight of sodium formate is heated slowly till the temperature reaches about 70*C to 80*C and as the reaction is exothermic, it can maintain itself between 95*C and 100*C. The reaction is, however, maintained at 100*C to 105*C for 2 hours. At the end of this period the water content of the reaction mixture is reduced by vacuum distillation to about 12% by weight to give after neutralisation with ammonia an oxidiser blend.
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Methylamine Hydrochloride from HMTA and Paraformaldehyde
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 at approximately 80°C, all paraformaldehyde dissolved. 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 40 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%.
Methylamine Hydrochloride from Ammonium Chloride and Paraformaldehyde
27 grams of ammonium chloride, 30 grams of paraformaldehyde (molar ratio 1:2), and 90 ml of water were gradually heated. At 80°C a clear solution was obtained, and the temperature was maintained at 104°C for four hours. Slightly more than one-third (9.06 grams) of the ammonium chloride was recovered, whilst 18.96 grams of pure methylammonium chloride were obtained. This equals 86% of the theoretical amount. The amount of dimethylammonium chloride produced was not estimated. It is not suggested from the results of this experiment that paraformaldehyde can economically be used on a large scale with advantage, since, quite apart from the relatively high cost, neither formic acid nor part of the unchanged aldehyde can be recovered as by-products.
Methylamine Hydrochloride from Hexamethylenetetramine (HMTA)
140 grams HMTA (1 mole) was slowly dissolved in 400 ml water and 400ml 37% HCl (4 moles) was added. If the hydrochloric acid is added directly to the HMTA, a lot of it is lost, as ammonium chloride starts to separate almost immediately. The mixture was heated on a temperature controlled heating plate, and the contents was slowly distilled while the temperature slowly rose from 100°C to 109°C during 1-2 hours, during which 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 last crop of crystals was very hard to crystallize, and care must be taken not to burn the contents of the flask, it must not be allowed to rise over, say 75°C. The white solids were placed in 150ml warm methanol (cheaper than denatured ethanol), and was filtered. The insoluble portion was recrystallized from water, to give 40 grams of pure ammonium chloride, which looked like very large snowflakes. The methanol solution was evaporated, recrystallized from methanol and washed with acetone, to give a deliquescent crystalline mass, which was dried in a desiccator over CaCl2.
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Ammonium Chloride is not soluble in alcohol.
Methylamine.hcl is much more soluble in hot alcohol than cold.
Both are soluble in water. Minimizing water aids separation.
Methylamine.hcl is not soluble in chloroform.
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John Ashcroft
June 13th, 2003, 11:13 PM
Reduction of nitromethane with Al/Hg amalgam is a cheap, high-yielding, mostly OTC process for preparing methylamine.

Mr Cool
June 14th, 2003, 10:54 AM
Yeah, that does work well, but many people here would consider converting MeNO2 to MeNH2 a crime :).
Also there's the Hofmann degradation of acetamide which I'll add to it, but the ones above seemed like the cheapest, with the easiest to get chemicals.

MnkyBoy
June 19th, 2003, 09:08 AM
The neighbor downstairs claims that the following results in excellent yields:

Place HMTA into a flask with a stirbar on top of a magnetic stirrer. Slowly add HCl until the HMTA barely disolves. Keep contents < 25 C. To this over the next say 24hrs with stirring add Zn + HCl (Zn = dust or from pennies) . Filter, distill off the MeAm. Condense till crystals are percipitated, wash with chloroform to rid di-MeAm.

Mr Cool
June 19th, 2003, 09:12 AM
Yeah I heard about adding Zn/HCl to increase yields. I've heard it mentioned as a catalyst, but have never read a specific procedure which uses this.

vulture
June 19th, 2003, 02:21 PM
Wouldn't the Zn/HCl be a necessary reagent as a reduction agent, reducing the HMTA to methylamine? Because Zn/HCl is the SOP for reducing organics.

Mr Cool
June 19th, 2003, 04:11 PM
Yes, reducing agent was my first thought, but I was reading a procedure that IIRC was posted by Rhodium, and at the end it said something along the lines of "Oh, I forgot the proportions of Zn and HCl? No, I didn't ;)." If it was a reducing agent, then proportions should have been mentioned, or at least stated that they were used in excess or whatever. Also I heard "catalyst" mentioned, but I can't think of a mechanism for its action :confused:.

Formaldehyde or formic acid are the reducing agents in the methods I mentioned. eg Hydrolysis of hexamine produces NH3 and CH2O in a 2:3 ratio. They then react in a 1:2 ratio, thus forming ammonium salts from the excess ammonia. One CH2O combines with the NH3, the other reduces the intermediate to form methylamine and formic acid.

NH4NO3 + 2 CH2O --> CH3NH3NO3 + HCOOH

This formic acid then takes the place of the reducing CH2O in further reactions:

NH4NO3 + CH2O + HCOOH --> CH3NH3NO3 + H2O + CO2