How to properly generate Methylamine gas to Methanol

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I have problem because I don't know how to properly generate Methylamine gas

I putted 100 grams of Methylamine in 80g of water and mixed in one beaker
Then I putted 200 grams of NaOH in erlenmeyer flask which was connected with silicone tubing to ice cold liebig condenser and then to Jar that had 3 Liters of Methanol (Methanol was -18 deegre C)
I then took the Methylamine solution with syringe and I squirted 60ml of this methylamine/water solution in the erlenmayer flask that had NaOH inside
then I immediately putted the stop cork with tubing on it so the gas was going throught ''cooled'' liebig condenser to bottom of Methanol jar
Then 5 seconds strong bubbling occured inside the Methanol jar and then it stopped
And when I wanted to open the stop cork with tubing in erlenmeyer flask (to put more Methylamine solution inside)
the methanol solution sucked back inside this erlenmayer and I lost 0.5 liters of methanol

I still have some Methylamine Hydrochloride left and I want to gas this inside of 3L of Methanol
What is the proper way to generate the Methylamine gas via the MeAM - NaOH route?
Can somebody please help me construct something that will finally work and produce Methylamine gas without suck back?

Please someone help me
you can write me in PM also
 

ACAB

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Hi, I'm not an expert, but I think that nothing sucks, but something presses.
Is the 3L methanol jar open? Where should the excess pressure go? And as soon as the Erlenmayer is opened, it pushes the methanol back.
I would suggest not opening the system, and slowly adding the supply of methylamine solution using a funnel placed on top.
I would discharge the excess pressure from the methanol jar into another open container filled with hydrochloric acid, methylamine is thereby neutralized and can be recovered by water evaporation as methylamineHCL.
In any case a closed system, otherwise dangerous pressure will build up.
I hope my statement helps you.
 

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thanks for answer

will have to try again i think with pressure release tube like you advised
 

G.Patton

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Best Method
Through experimentation, it was determined that the best method for extracting the MeNH2 from the aqueous solution is to raise the temperature of the solution while stirring. Gas is produced immediately upon stirring at standard temperature, and pressure and the solution begins to boil at 60 ºC. Copious amounts of MeNH2(g) can be obtained by gradually increasing the temperature of the solution between 60 ºC and 80 ºC at normal pressure. A reflux condenser and a gas washing tube filled with anhydrous MgSO4 to pre-dry the gas and 3A molecular sieve to provide a final drying are sufficient to remove any water vapor. (Note, use of NaOH to dry the gas is not recommended for the following reason: NaOH will form a hard moist cake at the vapor/NaOH interface. This thin cake will eventually impede gas flow, raising line pressure, and causing a joint to pop or explode--escaping toxic noxious MeNH2 fumes will quickly render the workplace uninhabitable. This is a fact based on experience, not idle speculation, so avoid the posted suggestion to use NaOH to dry MeNH2 gas: that suggestion is unsound and although a person can “get by” in the short term, in the long term it will eventually lead to catastrophe.)

As the temperature of the solution increases to 80 ºC, water vapor is observed condensing in the lower half of the reflux condenser. After a time at the same temperature, the production of MeNH2(g) begins to decrease. At this point, the partially spent solution is allowed to cool and is pumped out of the reactor flask (a peristaltic pump is ideal) and into a plastic (HDPE) carboy for further treatment to recover the remaining MeNH2. The reactor is reloaded with fresh 40 % solution and stirring and heating are applied, as above, until the temperature reaches 80 ºC and gas production diminishes, whereupon this partially spent solution is added to the contents of the carboy, and the reactor reloaded. In this fashion, a substantial amount of 40 % solution can be processed, without having to take the gas apparatus apart, nor expose the work area to MeNH2 fumes, nor with any solid residue remaining in the boiling flask.

The partially spent solution can then be further treated to obtain practically 100% of the remaining MeNH2. This is accomplished by addition of muriatic acid according to the reaction MeNH2(aq) + HCl(aq) = MeNH2•HCl(aq). The reactor should be maintained in an ice bath during acid addition because there is substantial heat generated by acid addition. Upon neutralization, the MeNH2•HCl solution is brought to a boil, the water and any MeNH2 vapor recovered by condensation, and the dry MeNH2•HCl can then be reacted with saturated NaOH solution to generate MeNH2(g) according to the reaction:
MeNH2•HCl(s) + NaOH(aq) = MeNH2 (g) + NaCl(aq)+ H2O​

There is an advantage obtained by first boiling off the major part of the MeNH2(g), prior to acid addition, since substantially less acid is consumed and substantially less hydrochloride salt is produced, therefore less NaOH is needed to convert the hydrochloride to a gas, etc., and less mess and hassle overall. In fact, a person could produce all the MeNH2 he or she might need by simple stirring and boiling of the initial 40 % solution, easily unloading and reloading the reactor, and save the task of reacting the spent solution with muriatic acid for some later date.

Absorption of MeNH2 in MeOH
It is assumed that members reading this post understand that one of the reasons for generating MeNH2 gas is to absorb that gas in cold, stirred MeOH. By weighing the MeOH before and after gas dissolution, the amount of MeNH2 recovered can be calculated, which is required for additional syntheses. Please note that some people suggested using a dispersion tube when absorbing MeNH2(g) into MeOH. That advice is not warranted and is unsound because it will increase line pressure on the system, which could lead to catastrophe. Do not follow those suggestions-do not use a dispersion tube. MeNH2(g) is readily absorbed in cold MeOH. The b.p. of MeNH2 is -6 ºC, so a salt water/ice bath is sufficient to condense vapors. Besides, MeNH2(g) is absorbed in MeOH at just about any temperature short of hot. 1/2” OD polyethylene tubing from the hardware store without any sort of dispersion device on the end of the tubing is sufficient for this purpose.

Suck-back control
Suck-back occurs when the amount of gas being generated is insufficient to compensate for the amount of gas being absorbed. When the production of gas diminishes, suck-back will occur. The suck-back of MeOH with MeNH2 gas can be rapid and violent. Continual suck-back indicates that it is time to replace the spent solution in the reactor with fresh 40 % solution. Suck-back is controlled by stop-cocks to relieve line pressure. However, a trap must be installed between the gas drying tube and the receiver for those inevitable times when the operator looks the other way and valuable MeNH2/MeOH solution is sucked into the system. The trap must be larger than the volume of MeOH in the receiver, so that nothing is lost and nothing can reach the reactor. If MeOH were ever to be sucked back into the hot reactor where the temperature is above the b.p. of MeOH, the resulting explosion of glassware will get everybody’s attention. But be assured that this is not possible with the described set-up.​
VshtZDrBne
WptHbI8D2o

trap and stop-cocks
 
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JustBrowsing223

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Best Method
Through experimentation, it was determined that the best method for extracting the MeNH2 from the aqueous solution is to raise the temperature of the solution while stirring. Gas is produced immediately upon stirring at standard temperature, and pressure and the solution begins to boil at 60 ºC. Copious amounts of MeNH2(g) can be obtained by gradually increasing the temperature of the solution between 60 ºC and 80 ºC at normal pressure. A reflux condenser and a gas washing tube filled with anhydrous MgSO4 to pre-dry the gas and 3A molecular sieve to provide a final drying are sufficient to remove any water vapor. (Note, use of NaOH to dry the gas is not recommended for the following reason: NaOH will form a hard moist cake at the vapor/NaOH interface. This thin cake will eventually impede gas flow, raising line pressure, and causing a joint to pop or explode--escaping toxic noxious MeNH2 fumes will quickly render the workplace uninhabitable. This is a fact based on experience, not idle speculation, so avoid the posted suggestion to use NaOH to dry MeNH2 gas: that suggestion is unsound and although a person can “get by” in the short term, in the long term it will eventually lead to catastrophe.)

As the temperature of the solution increases to 80 ºC, water vapor is observed condensing in the lower half of the reflux condenser. After a time at the same temperature, the production of MeNH2(g) begins to decrease. At this point, the partially spent solution is allowed to cool and is pumped out of the reactor flask (a peristaltic pump is ideal) and into a plastic (HDPE) carboy for further treatment to recover the remaining MeNH2. The reactor is reloaded with fresh 40 % solution and stirring and heating are applied, as above, until the temperature reaches 80 ºC and gas production diminishes, whereupon this partially spent solution is added to the contents of the carboy, and the reactor reloaded. In this fashion, a substantial amount of 40 % solution can be processed, without having to take the gas apparatus apart, nor expose the work area to MeNH2 fumes, nor with any solid residue remaining in the boiling flask.

The partially spent solution can then be further treated to obtain practically 100% of the remaining MeNH2. This is accomplished by addition of muriatic acid according to the reaction MeNH2(aq) + HCl(aq) = MeNH2•HCl(aq). The reactor should be maintained in an ice bath during acid addition because there is substantial heat generated by acid addition. Upon neutralization, the MeNH2•HCl solution is brought to a boil, the water and any MeNH2 vapor recovered by condensation, and the dry MeNH2•HCl can then be reacted with saturated NaOH solution to generate MeNH2(g) according to the reaction:
MeNH2•HCl(s) + NaOH(aq) = MeNH2 (g) + NaCl(aq)+ H2O​

There is an advantage obtained by first boiling off the major part of the MeNH2(g), prior to acid addition, since substantially less acid is consumed and substantially less hydrochloride salt is produced, therefore less NaOH is needed to convert the hydrochloride to a gas, etc., and less mess and hassle overall. In fact, a person could produce all the MeNH2 he or she might need by simple stirring and boiling of the initial 40 % solution, easily unloading and reloading the reactor, and save the task of reacting the spent solution with muriatic acid for some later date.

Absorption of MeNH2 in MeOH
It is assumed that members reading this post understand that one of the reasons for generating MeNH2 gas is to absorb that gas in cold, stirred MeOH. By weighing the MeOH before and after gas dissolution, the amount of MeNH2 recovered can be calculated, which is required for additional syntheses. Please note that some people suggested using a dispersion tube when absorbing MeNH2(g) into MeOH. That advice is not warranted and is unsound because it will increase line pressure on the system, which could lead to catastrophe. Do not follow those suggestions-do not use a dispersion tube. MeNH2(g) is readily absorbed in cold MeOH. The b.p. of MeNH2 is -6 ºC, so a salt water/ice bath is sufficient to condense vapors. Besides, MeNH2(g) is absorbed in MeOH at just about any temperature short of hot. 1/2” OD polyethylene tubing from the hardware store without any sort of dispersion device on the end of the tubing is sufficient for this purpose.

Suck-back control
Suck-back occurs when the amount of gas being generated is insufficient to compensate for the amount of gas being absorbed. When the production of gas diminishes, suck-back will occur. The suck-back of MeOH with MeNH2 gas can be rapid and violent. Continual suck-back indicates that it is time to replace the spent solution in the reactor with fresh 40 % solution. Suck-back is controlled by stop-cocks to relieve line pressure. However, a trap must be installed between the gas drying tube and the receiver for those inevitable times when the operator looks the other way and valuable MeNH2/MeOH solution is sucked into the system. The trap must be larger than the volume of MeOH in the receiver, so that nothing is lost and nothing can reach the reactor. If MeOH were ever to be sucked back into the hot reactor where the temperature is above the b.p. of MeOH, the resulting explosion of glassware will get everybody’s attention. But be assured that this is not possible with the described set-up.​
G.Patton@G.Patton Sorry for the long reply, this will be a 2 part question.
1. Does this means just boiling 40% methylamine hcl aq solution (1000ml H2O + 400 g methylamine hcl? If thats the case than maybe you got an idea how much methylamine hcl would stay in the spent solution? Im just trying to understand how efficient the process would be.

So the apparatus would be something like - 2L 2neck roundbottom with thermometer and 50cm liebig condeser attached to gas drying tube and finished with molecular sieve drying flask , suckback controll and hoes/tube that goes into watter? (I want to get 40% aq solution for 4mmc synthesis)

Also, is the molecular sieve drying needed for making aq. solution?

2. If i would go the aq. NaOH route, i imagine the apparatus as follows, 2L 2neck rbf with pressure equalised dropping funnel in one and condenser in the other neck, continued by drying and suckback part, is that correct?
Maybe you could share what should be the methylamine hcl and watter ratio in reaction flask, as well as NaOH watter ratio in the dropping funnel?

I would be super happy for any info that could help me with part of the project. I simply dont have an option to safely purchase 40% solution.
 

G.Patton

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@G.Patton Sorry for the long reply, this will be a 2 part question.
1. Does this means just boiling 40% methylamine hcl aq solution (1000ml H2O + 400 g methylamine hcl? If thats the case than maybe you got an idea how much methylamine hcl would stay in the spent solution? Im just trying to understand how efficient the process would be.

So the apparatus would be something like - 2L 2neck roundbottom with thermometer and 50cm liebig condeser attached to gas drying tube and finished with molecular sieve drying flask , suckback controll and hoes/tube that goes into watter? (I want to get 40% aq solution for 4mmc synthesis)

Also, is the molecular sieve drying needed for making aq. solution?

2. If i would go the aq. NaOH route, i imagine the apparatus as follows, 2L 2neck rbf with pressure equalised dropping funnel in one and condenser in the other neck, continued by drying and suckback part, is that correct?
Maybe you could share what should be the methylamine hcl and watter ratio in reaction flask, as well as NaOH watter ratio in the dropping funnel?

I would be super happy for any info that could help me with part of the project. I simply dont have an option to safely purchase 40% solution.
JustBrowsing223
Does this means just boiling 40% methylamine hcl aq solution (1000ml H2O + 400 g methylamine hcl? If thats the case than maybe you got an idea how much methylamine hcl would stay in the spent solution? Im just trying to understand how efficient the process would be.
Hello, no. There is written about methylamine water solution, not about methylamine hydrochloride. There is big difference. If you wanna get methylamine free base, you need add there an alkali. There is the reaction equation for you:
MeNH2•HCl(s) + NaOH(aq) = MeNH2 (gas) + NaCl(aq)+ H2O
2L 2neck rbf with pressure equalised dropping funnel in one and condenser in the other neck, continued by drying and suckback part, is that correct?​
You need equimolar amount (1:1 in moles with methylamine*hcl) of NaOH in about 50% aq sln.

This is about methylamine free base in aq solution:
You need rbf with a reflux condenser and a gas washing tube after his filled with anhydrous MgSO4 to pre-dry the gas and 3A molecular sieve to provide a final drying are sufficient to remove any water vapor. You can add there instantly via first neck or use two neck rbf (it's better option).​
 

G.Patton

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Then 5 seconds strong bubbling occured inside the Methanol jar and then it stopped
ResearcherIt's quite strange cuz you have excesses of pressure.
And when I wanted to open the stop cork with tubing in erlenmeyer flask (to put more Methylamine solution inside)
the methanol solution sucked back inside this erlenmayer and I lost 0.5 liters of methanol
You have to use Pressure Equalizing Dropping Funnel, trap between condenser and receiver flask with MeOH and stop-cock btw reaction flask with NaOH and condenser.

When you want to stop addition of MeNH2 to receiver flask, close stop-cock btw reaction flask with NaOH and condenser and then open drip funnel tap. Also, make connection with atmosphere from receiver flask via additional stop-cock.​
 
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hunter12

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It's quite strange cuz you have excesses of pressure.

You have to use Pressure Equalizing Dropping Funnel, trap between condenser and receiver flask with MeOH and stop-cock btw reaction flask with NaOH and condenser.

When you want to stop addition of MeNH2 to receiver flask, close stop-cock btw reaction flask with NaOH and condenser and then open drip funnel tap. Also, make connection with atmosphere from receiver flask via additional stop-cock.​
G.PattonDon't you have atleast a diagram of the setup? I guess it would be of great help
 

ACAB

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So my statement was not quite wrong then :D
You have to use Pressure Equalizing Dropping Funnel, trap between condenser and reciver flask with MeOH and stop-cock btw reaction flask with NaOH and condenser.
G.PattonWould I also have to use a trap if I used a check valve before the methanol receiver?
 

G.Patton

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Would I also have to use a trap if I used a check valve before the methanol receiver?
PennywiseYes, of course. You can't react immediately in any situation. This equipment prevents unpleasant consequences...
 

ACAB

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Yes, of course. You can't react immediately in any situation. This equipment prevents unpleasant consequences...
G.PattonBut a non-return valve (check valve) would prevent methanol from coming out of the receiver in the direction of the reactor, and would do so fully automatically as soon as the direction of flow changes.
 

G.Patton

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ACAB

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Yes, if you can buy it.
G.PattonYeah sure, I have one, was cheap, cost few dollars and is practical.
some links...
Use it at the moment on the vacuum pump.
 

tajira

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How can I measure obtained Gas ? I need it to MDMA synthesis 300g in MeOH
 

Mr.Blanks00

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hello sir, if you want to make 40% methylamine in water, it means that the methanol is replaced with water, sir, hello sir, can you explain how to find out that all the methylamine gas has been absorbed in methanol by weighing it before and after absorbing the methylamine gas.
 

Stretcher5335

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Why isnt anyone talking about obtaining methylamine via nitromethane? And if anyone can shine some light on is it possible run reaction (nitro+alu. foil) with out ketone and use the methylamine generated in a future reaction say with p2p
 

HerrHaber

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Why isnt anyone talking about obtaining methylamine via nitromethane? And if anyone can shine some light on is it possible run reaction (nitro+alu. foil) with out ketone and use the methylamine generated in a future reaction say with p2p
Stretcher5335as long as you manage the gas you may try separately but there is certainly at least a method i read here somewhere or maybe rhodium chem archives that does this in situ as it makes more sense and MeNO2 should be added at such rate that methylamine can't escape easily out as a gas
 

diogenes

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as long as you manage the gas you may try separately but there is certainly at least a method i read here somewhere or maybe rhodium chem archives that does this in situ as it makes more sense and MeNO2 should be added at such rate that methylamine can't escape easily out as a gas
HerrHaberDo you have the link to this by any chance? thanks
 

HerrHaber

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Do you have the link to this by any chance? thanks
diogenesas a matter of a fact in the video section there is an excerpt from Hamillton's pharmacopeia where MDMA is obtained from safrole, the methylamination reaction is Al\Hg with MeNO2 in a HDPE wallpaint buket makeshift reactor with a ducttape holding the power on a drill turned to top stirrer but that thing worked presentably decent in my honest opinion

P.S. too lazy to seek the link so I leave you the joy of finding it as well as a very effective solution for some common problems like colloids (emulsions) they solve by the means of a "conventional dilding apparatus" that is brilliant
 

Stretcher5335

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"Dilding emulsions" sounds bad enough and God forbid any of this ends up in court you dont want exhibit A being your ol' ladys best friend so i use a facial scrubber works great and doesnt take 10 C batterys

PMD Clean Mini Purple Facial Cleansing Device
 

Stretcher5335

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Also for anyone thinking about the 5 Gal reactor yes a drill works great but another option is an ice cream churn. Look into it over head stirrer reactor sits inside another which you place ice, salt, water, ect Plus the stirrer is for tough thick material. You do need to coat the inside barrel or use your own modified for the stirrer to lock in
Elite Gourmet EIM-308L# 4 Qt. Electric Motorized Maker Ice & Rock Salt, 4Qt. Freezing Canister, Creamy Ice Cream, Gelato, Frozen Yogurt, or Sorbet, Recipe Booklet, 4 Quart, Mint
 
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