Everything disolved no sludge on the bottom after the reaction. I did try to swirl the flask a couple of times once the hexamine tablets started disolving to ensure all of them did. Condensor setup as if for reflux for the entire reaction. I believe running the reaction 104C or lessand condensing the formaldyde gas back into the reaction do help yields significantly especially when running this for 24 hours not 6 to 8 at 104C.
Once the reaction cools you pour out amounts to evaporate slowly. Filtering out the wax is very easy since it hardens and floats to the top once it cools. Alot stays stuck to the glassware if you do the main part of the evaporation in the glassware then let it cool. Evaporating it off slowly and venting the fumes outside did not stink up my area though I would not recommend it for an apartment dweller. Used a fish bubbler to push air in and a dryer hose to exhaust the air out. It did take a week or more to reduce it down to the point where reducing it further required filtering and teflon frying pans. A slow evaporation will keep the fumes you vent low enough noone notices.
Temperature 102 or 103C, which has worked fine on smaller scale reactions. I live at a high elevation and all of the smaller reactions ran fine despite never hitting 104C. It is definitely methylamine. Clear flakes that completely disolve in your fingers.
If using wax coated hexamine tablets add 7% to the weight of the hexamine to compensate for the weight of the wax. For the reaction I ran the 7 percent for the wax binders is included in the weight. Hexamine fuel tablets are a source of hexamine for those of us staying below radar.
I added water because that is what the recipe from the methylamine faq on Rhodium uses. I did reduce the water because I was using 31.5% muratic acid which has more water not the 37% percent hcl that the recipe below from rhodium uses.
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, to give XX grams of methylamine hydrochloride (XX moles) as a fluffy soft powder. Calculated on the two moles of amine nitrogen put into the equation, XX% became methylamine, and 37% (0.75 mole) became ammonium chloride. The net yield of methylamine is therefore XX% of the processed nitrogen.
