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confused
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Quote: Originally posted by elementcollector1  | | Apparently, anything will work for filtration (except for a hand pump), even vacuum cleaners. For distillation, I would honestly recommend an
aspirator - no suckback or chemical traps necessary for a good plastic one. |
yes, but my workarea/lab is not near a water source and rigging up my waterpump with an aspirator while maintaining water flow through the condenser
while doing a distillaion isn't really feasible at the moment.
so, how powerful would a standard lab vacuum pump usually be?
and while we're at it, what unit do you guys use to calculate negative presure(vacuum)? Pa, bar, mmHg, psi or atm?
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Morgan
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Would candle wax dissolve in methanol if it were melted or would it tend to separate?
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confused
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paraffin wax is miscible in methanol,
however, the melting point of paraffin wax is really quite close to the boiling point of methanol, so you would have to continously add more methanol
to prevent all of it from evapourating/boiling away unless you use a reflux setup
not to mention that methanol vapours are flamable, so, i highly reccomend using somthing other than an open flame or anything that could possibly
create a spark while doing it.
out of curiosity, what would you want to do that for?
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DraconicAcid
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| Quote: Originally posted by confused | paraffin wax is miscible in methanol,
however, the melting point of paraffin wax is really quite close to the boiling point of methanol, so you would have to continously add more methanol
to prevent all of it from evapourating/boiling away unless you use a reflux setup |
Are you sure? I seem to recall finding that heptane didn't mix with methanol as well as I expected, and paraffin would be even less likely to
dissolve in it.
The Merck Index says that paraffin is insoluble in water and alcohol.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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Morgan
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| Quote: Originally posted by confused | paraffin wax is miscible in methanol,
however, the melting point of paraffin wax is really quite close to the boiling point of methanol, so you would have to continously add more methanol
to prevent all of it from evapourating/boiling away unless you use a reflux setup
not to mention that methanol vapours are flamable, so, i highly reccomend using somthing other than an open flame or anything that could possibly
create a spark while doing it.
out of curiosity, what would you want to do that for? |
I was pondering the possibility of using paraffin as fuel but initially starting the engine with methanol. Methanol has some good qualities but the
boiling point so low that perhaps transitioning to wax would work better in some cases. For my purposes, gasoline ruins the fuel/air ratio and becomes
too rich, often so much so you can't even get the flame front to chase down into the combustion chamber. Paraffin wouldn't start evaporating until
heated to a fairly "high" temperature. I'm trying to keep it simple, the engine feeding off an evaporating pool of fuel in the bottom of the
combustion chamber.
I've tried other fuels and some blends - nitromethane, acetone, ether, ethanol, isopropyl, and gasoline.
The store I was at today had nitro for $30.00 a half gallon. It's kind of expensive and doesn't really work for what I do.
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confused
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| Quote: Originally posted by DraconicAcid | | Quote: Originally posted by confused | paraffin wax is miscible in methanol,
however, the melting point of paraffin wax is really quite close to the boiling point of methanol, so you would have to continously add more methanol
to prevent all of it from evapourating/boiling away unless you use a reflux setup |
Are you sure? I seem to recall finding that heptane didn't mix with methanol as well as I expected, and paraffin would be even less likely to
dissolve in it.
The Merck Index says that paraffin is insoluble in water and alcohol. |
...my bad, i was going by the assumption that organic compounds dissolve in organic solvents 
but i just checked the polarity of paraffin wax and methanol. Paraffin wax is non-polar while methanol is polar
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Morgan
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Some tidbit pertaining to some possible exceptions of solubility of "wax compounds" and alcohols.
"Ethanol has been used advantageously
as a co-solvent to modify the polarity of pressurized
carbon dioxide or water for the extraction of natural products
[6, 7]. More recently the application of hot ethanol to recover
waxes from flax fiber processing waste containing cuticle tissue
was also demonstrated [8]. These results motivated the
current investigation of the temperature-dependent solubility of fatty esters in ethanol and the possibility of use in biomassto-
ethanol conversion."
Temperature-dependent solubility of wax compounds in ethanol
http://naldc.nal.usda.gov/download/44460/PDF
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Organikum
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electrolytic activation of iron filings
Randolph Carter who I believe knows what he does speaks in this post of electrolytic preparation of purchased iron filings, which were used in a nitropropene reduction to the correspondending ketone.
Now the only "preparation" or activation of iron for such reactions I know of is the short wash in diluted HCl....
But the electrolytic sounds interesting and promising.
If I only had a clue how to do it.
Anybody in the know willing to help me out?
regards
/ORG
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DraconicAcid
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| Quote: Originally posted by Morgan | Some tidbit pertaining to some possible exceptions of solubility of "wax compounds" and alcohols.
"Ethanol has been used advantageously
as a co-solvent to modify the polarity of pressurized
carbon dioxide or water for the extraction of natural products
[6, 7]. More recently the application of hot ethanol to recover
waxes from flax fiber processing waste containing cuticle tissue
was also demonstrated [8]. These results motivated the
current investigation of the temperature-dependent solubility of fatty esters in ethanol and the possibility of use in biomassto-
ethanol conversion."
Temperature-dependent solubility of wax compounds in ethanol
http://naldc.nal.usda.gov/download/44460/PDF |
Interesting paper. It shows that at 45oC, the solubility of these waxes (all of them esters, not the paraffin sort) is on the order of 0.05 g/L.
That's not very soluble at all.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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confused
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Hi, is there any way to make or extract sodium dodecyl sulfate from commonly avalible products
without oleum, chlrosulfuric acid or SO3?
I need some for preparation of some buffer solutions for microbiology
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LiD
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Is there any known method to turn an enamine to an enol ether? I found only references to turn them back to ketones... But I would need to get an enol
ether and not get back the oxo.
Thanks!
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solo
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I would like to know how to add a methoxy group ....starting with,
.....and end up with this,
It's better to die on your feet, than live on your knees....Emiliano Zapata.
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Metacelsus
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I have a question regarding the use of MMO anodes in acidic conditions. I've been doing some work with chlorinating organic compounds using chlorine
generated in situ via electrolysis, but to avoid the haloform reaction I need acidic conditions. I have been using graphite anodes, but they corrode
rapidly into annoying black sludge. Will a MMO anode stand up to acidic conditions (specifically HCl)?
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elementcollector1
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If it stands up to Cl2, I'd be willing to wager the same for HCl. Mind you, platinum or platinum-plated is where it's at.
Elements Collected:52/87
Latest Acquired: Cl
Next in Line: Nd
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Metacelsus
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OK, I'm trying it now. I hope you're right!
By the way, where can you get platinum electrodes? Seems expensive.
[Edited on 28-5-2013 by Cheddite Cheese]
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Organikum
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| Quote: Originally posted by confused | | Quote: Originally posted by elementcollector1 | | Apparently, anything will work for filtration (except for a hand pump), even vacuum cleaners. For distillation, I would honestly recommend an
aspirator - no suckback or chemical traps necessary for a good plastic one. |
yes, but my workarea/lab is not near a water source and rigging up my waterpump with an aspirator while maintaining water flow through the condenser
while doing a distillaion isn't really feasible at the moment.
so, how powerful would a standard lab vacuum pump usually be?
and while we're at it, what unit do you guys use to calculate negative presure(vacuum)? Pa, bar, mmHg, psi or atm? |
In this case you want a chemical resistant diaphragm pump with PTFE heads, it is not about power but resistance and tolerance to vapors in this case.
In the end it solely depends on the size of your briefcase.
There are heaps of vacuum related threads here offering all answers you might look for, pls search.
We at SCM, well at the least the real ones, measure vacuum in "s**k!" a unit which is directly derived from the english weight "stone". The detailed
information is in the "over 18" section of SCM.
regards
/ORG
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halogen
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http://www.britannica.com/EBchecked/topic/17932/aluminosilic...
"Aluminosilicate glasses find applications similar to those of borosilicates, but the former can stand higher operating temperatures; glasses with
relatively high alumina contents and no boric oxide are exceptionally resistant to alkalies. "
That sounds smashing, baby. Has anybody heard of it used; or why isn't it common? Just hard to melt, or another flaw?
Solo: There was a synthesis of 3-something-pyr, nicotine maybe, wherein first was brominated, then chlorinated, bromine removed. It's ugly but what
else? Demethylenation? Best luck creating a special enzyme, actually, it's a long shot but some kind of hydroxylase might work!! A cactus enzyme eh?
It works fa them.
[Edited on 1-6-2013 by halogen]
[Edited on 1-6-2013 by halogen]
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Organikum
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Gorilla Glass?
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halogen
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For labware though. I found some stuff: centrifuge tubes, raw tubing, it's apparently helium proof. It's not common, it can't be that much more
difficult to form, looking at brittanica's mp diagram. I'd thought chemists would appreciate alkali&heat resistance.
And - this is the answer! :
"Aluminosilicate glass is very difficult to work with because it is very prone to reboil. That is, while bringing it a working temperature, the glass
develops bubbles over the surface that are impossible to remove. One other challenge with aluminosilicate glass, which is different from other
glasses, is that you can't clean itwith hydrofluoric acid (see Sec. 4.1.10). If attempted, it will cause the surface to develop a translucent sheen
that is also impossible to remove. It is safe (for the glass) to clean the surface with nitric acid"
From http://www.scribd.com/doc/79709916/7/Different-Types-of-Glas...
[Edited on 2-6-2013 by halogen]
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Variscite
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In a water pump for a condenser/distillation setup, what would be the ideal rate of flow (in GPH) for the pump to have?
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chemcam
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| Quote: Originally posted by Variscite | | In a water pump for a condenser/distillation setup, what would be the ideal rate of flow (in GPH) for the pump to have? |
I don't think it really matters what the GPH is as long as there is a constant flow and the reservoir is big enough to allow for a constant
temperature throughout the distillation.
I use a salvaged desktop fountain pump, it is very small, but adequate for normal distillations. However, when I setup for refluxing I have to run two
pumps together to get constant vertical flow, or elevate the reservoir.
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Dr.Bob
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| Quote: Originally posted by confused | Hi, is there any way to make or extract sodium dodecyl sulfate from commonly avalible products
without oleum, chlrosulfuric acid or SO3?
I need some for preparation of some buffer solutions for microbiology |
Many shampoos and detergents are nearly pure sodium dodecyl sulfate solutions already. If you find a shampoo without dyes or frangrance, it might be
good enough for simple biology work. Just look at the labels.
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Boron Trioxide
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Quick question about HCl
I recently purchased some toilet cleaner stating to be 10% HCl, it sounded like a liquid in the bottle though after checking it is more of a
disgusting gel, is there anyway to extract the HCl, perhaps thermal decomposition and re-absorption in water?
Thanks for any answers.
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manimal
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When chlorinating an amino alcohol (tertiary amine, secondary alcohol) with ZnCl2 and HCl, would complexes ruin the party?
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Tdep
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Does plastic destroy chlorine dioxide, ie can I use a plastic testtube when making the gas or do I have to stick with glass (worried about explosions
+ shrapnel)
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