from "SIMPLE to COMPLEX "or from methylamine HCI to methylamine 40%

mejdubulok

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Preparation of the maximum pure 40% methylamine solution from methylamine hydrochloride can be carried out as follows:
Materials:
- Methylamine hydrochloride (about 160 g)
- Distilled water (about 240 ml)
- Glass flask with a volume of about 500 ml
- Magnetic stirrer
- Thermometer
- Unloading crane
- Glass pipette
Steps:
1. Prepare 240 ml of distilled water in a glass flask with a volume of about 500 ml.
2. Put methylamine hydrochloride in a flask of water.
3. Place the flask on the magnetic stirrer and start stirring.
4. Preheat the mixture to a temperature of 50-60°C, using a thermometer to control the temperature.
5. Continue heating and stirring until the methylamine hydrochloride is completely dissolved.
6. Bring the volume of the solution to 400 ml, adding distilled water, if necessary.
7. Cool the mixture to room temperature while continuing to stir.
8. Adjust the pH to a value of 10-11 using a 10% NaOH solution.
9. Check the concentration of methylamine in the solution using test strips or another method, and, if necessary, adjust the concentration by adding either water or methylamine hydrochloride.
10. Leave the mixture for a few hours or overnight so that all impurities settle to the bottom of the flask.
11. Filter the solution through a filter to remove any remaining impurities.
12. Ready-made methylamine 40% solution can be used in appropriate applications.
Please note that when using any chemicals, appropriate safety measures must be observed, including but not limited to: work in a well-ventilated area, use protective clothing and gloves.
 
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G.Patton

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From 160g of methylamine hydrochloride you'll get 73.6g of methylamine free base, dissolved in 400 ml water. It will be 18.4% methylamine aq solution. Not 40%.
In addition, you'll get 138.5g of NaCl in this solution, which will not be dissolved completely because of over saturation of water. NaCl solubility is 360 g/L (25°C).
It's important to say that MeNH2 very volatile and evaporates quite easy. So that, It's necessary to close the flask tightly. The best option is using methylamine solution directly after preparation.

Here, I posted BB Forum team methods of methylamine water and methanol solution preparations from methylamine hydrochloride.

 

Ortist

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Why do you think this method gives you 50% methylamine? You are using approx 7.45 mol of methylamine HCL which after basification will yeld 7.45 mol of methylamine gas which is approx 232g dissolved in 1134ml of water. It is far from 50%. The reaction itself produces 7.45mol of water in addition to your 1L

To get your %% above 25% you need to make a gas generator and bubble methylamine gas thru water, then weigh the receiving flask to find out your real percentage
 
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Brambus

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Thank you guys for the post/ comment! I have an additional question.
Wich reagent does need to be used in the gas genarator, to make methylamine gas out of the methylamine hcl?
Hope to hear from you!
 

Brambus

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Got it, it is NaOh. Already got my answer but i did not connect the dods yet😅
 
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