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Utilizing Stove Hood Vent for Venting A/B

Migrated topic.
Toshido

Toshido

Research & Development
Before I continue, this is in no way a clandestine extraction. I simply want to know if this would be an awesome way to minimize smells from NaOH and N-Heptane (Bestine Thinner).

Gas line will be turned off. No flames needed for my process. I will be using a hot plate and magnetic stirrer.

I am covering my stove top with a flat foundation, and putting my hot plate and magnetic stirrer on top of that so that I can turn on my stove vent (above the stove) to ventilate any smells. As I do not want the smell (primarily my Heptane) to travel out of my kitchen or have me inhale it.

Main question is, is a fan sucking up air going to effect the natural evaporation process of my A/B in an open Erlenmeyer flask? Because I want to know if I should add more water (50ml) to account for that, as my measurements are precise.

Thank you. Please refer to my Tek if you need specifics.

My ATB Tek

One love.
 
Evaporation of water from a flask, especially an Erlenmeyer, would be among the least of your worries. You would need to be certain that the cooker hood is safe for flammable solvents like heptane. Presumably it has a brushless motor?
And doesn't vent anywhere inopportune?

Using the pertinent data you could form the basis of a safety check by calculating the maximum vapour concentration of heptane that will pass through the cooker hood - something that's safer to slightly overestimate. Compare this with the explosive limits of heptane (which is what minimum or maximum concentration of it in air explodes when ignited - there is an upper as well as a lower limit and it is the lower one that is important here).

Relevant anecdote here is that back in the 1970's some guys in a pathology lab were evaporating ether from some faecal specimens, next to a fan in the ground floor window when some poor unfortunate soul chose to light a cigarette outside. Cue joke about the sh*t hitting the fan... True story though.

Fortunately, heptane is way less flammable than diethyl ether both in terms of volatility and the ignition temperature.
 
downwardsfromzero said:
Evaporation of water from a flask, especially an Erlenmeyer, would be among the least of your worries. You would need to be certain that the cooker hood is safe for flammable solvents like heptane. Presumably it has a brushless motor?
And doesn't vent anywhere inopportune?

Using the pertinent data you could form the basis of a safety check by calculating the maximum vapour concentration of heptane that will pass through the cooker hood - something that's safer to slightly overestimate. Compare this with the explosive limits of heptane (which is what minimum or maximum concentration of it in air explodes when ignited - there is an upper as well as a lower limit and it is the lower one that is important here).

Relevant anecdote here is that back in the 1970's some guys in a pathology lab were evaporating ether from some faecal specimens, next to a fan in the ground floor window when some poor unfortunate soul chose to light a cigarette outside. Cue joke about the sh*t hitting the fan... True story though.

Fortunately, heptane is way less flammable than diethyl ether both in terms of volatility and the ignition temperature.
Click to expand...

All I know is that it has a flash point of 20C. But I didn't think about the motor of the fan. That would worry me. Best I just move the set up to the living room where there is much more open space and to do my pulls. I can always open the sliding doors to outside, but since it's winter here, the cold air would just blow in. Thanks for your help!
 
downwardsfromzero said:
You would be warming heptane above its flashpoint to get decent pulls, then. Do you have a garden, shed or garage?
Click to expand...

If there are no flames present in my process, then I needed worry about the flash point do I?

Edit: Evap test complete. The bestine barely smells at all unless you give it a direct puff. Fans blowing around the room on low dissipate it to the extent that you can't smell it at all. Still, I'm glad I asked about the stove vent. Best not to mix fuel with unknown electrical sources that may be within a vent.
 
If it's cold and dry there is still a risk of ignition through electrostatic discharges. That would be pretty unlucky though!

There's a way of calculating whether your solvent will form a localised concentration that is capable of ignition (with reference to exceeding the lower explosive limit, LEL) by using the volume of the room, the (molar) amount of solvent, and the molar gas constant. It would also be prudent to consider the vapour density of heptane in case it accumulates at ground level, although that starts getting a bit more complicated.

The main thing is to ascertain that the amount of heptane that evaporates at the temperature of your extraction will not reach, say, 10% of the LEL when dispersed throughout the workspace. You could also do this with regards to the stove hood since it is desirable to vent the fumes externally rather than blowing them around your living space.

You can probably look up the specs of your stove hood fan and motor too.
 
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