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DrP
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One of my suppliers last year sent me some samples of an alternative solvent for general white spirits. Their suggested uses were as a cleaning
solvent safer than white white spirit and as a possible solvent for a coating system. The trade name was STEPOSOL and was listed as a METHYL SOYATE
& ETHYL LACTATE BLEND. The MSDS said it was a methyl ester/ethyl lactate. It seemed to be an adequate like for like replacement for cleaning
purposes - I haven't tried any real chemistry with it though.
PS - it is made from Soya beans apparently. Thus the greenery.
[Edited on by DrP]
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MagicJigPipe
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Speaking of that Sauron, I've always wondered if there's ever been an incident with cigarette smoking and pure grain alcohol. As in a severly burned
mouth and/or esophagus.
Back on topic.
In my opinion, a lot of the compounds that we already use are more "green" than people think. For example, acetone (correct me if I'm wrong) and
methanol break down relatively easily into harmless products in the environment.
Now, of course, aromatics and saturated HCs are different.
"There must be no barriers to freedom of inquiry ... There is no place for dogma in science. The scientist is free, and must be free to ask any
question, to doubt any assertion, to seek for any evidence, to correct any errors. ... We know that the only way to avoid error is to detect it and
that the only way to detect it is to be free to inquire. And we know that as long as men are free to ask what they must, free to say what they think,
free to think what they will, freedom can never be lost, and science can never regress." -J. Robert Oppenheimer
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Sauron
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Under no circumstances would I regard methanol as a benign substance. It is too toxic and too readily absorbed for us poor humans to regard it as
green. Its environmental fate is formic acid, and salts thereof, via formaldehyde.
Not all aromatic hydrocarbons are all that nasty. Some are and some aren't. There is nothing about aromaticity that is, in and of itself, hazardous.
Sic gorgeamus a los subjectatus nunc.
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microcosmicus
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And, of course, the production of acteone by destructive distillation of
calcium acetate is about as green as manufacturing process come ---
cook vinegar and chalk, you even get to recycle the chalk. The same
could be said for the destructive distillation of wood to produce MeOH.
Also, Weizmann's industrial fermentation process for acetone sounds
like it ought to be green (or whatever color the microbes come in).
Hmm . . . maybe the shtick with the old dood in the rocking chair isn't
so bad an idea after all. I could see environmentally conscious consumers
going for paint thinners made the old way from wood and vinegar.
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microcosmicus
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Acetone, on the other hand, seems more benign, at least according
to eco-usa.net ( http://www.eco-usa.net/toxics/acetone.shtml ) :
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Acetone enters the air, water, and soil as a result of natural processes and human activities. Acetone occurs naturally in plants, trees, volcanic
gases, and forest fires. People and animals breathe out acetone produced from the natural breakdown of body fat. Acetone is also released during its
manufacture and use, in exhaust from automobiles, and from tobacco smoke, landfills, and certain kinds of burning waste materials. The levels of
acetone in soil increase mainly because of acetone-containing wastes being buried in landfills. Acetone is present as a gas in air. Some acetone in
air is lost when it reacts with sunlight and other chemicals. Rain and snow also remove small amounts of acetone from the atmosphere and, in the
process, deposit it on land and water. About half the acetone in a typical atmosphere at any time will be lost in 22 days. Microbes (minute life
forms) in water remove some acetone from water. Some acetone in water will evaporate into air. About half the acetone in a stream will be removed from
water in less than a day. Fish do not store acetone from water in their bodies. Microbes in soil remove part of the acetone in soil. Some is lost from
soil by evaporation. Acetone molecules do not bind tightly to soil. Rainwater and melted snow dissolve acetone and carry it deeper into the soil to
groundwater.
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According to the Dow product safety assessment, most acetone in the
environment comes from natural sources:
http://www.dow.com/productsafety/finder/acetone.htm
The EPA removed acetone from the list of bad chemicals, pointing out that the
substitutes were worse! (Sounds like justification for Sauron's skepticism.)
http://www.epa.gov/fedrgstr/EPA-TRI/1995/June/Day-16/pr-15.h...
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BromicAcid
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Again, I've tried to shift the subject from the Green aspect of things simply because it can cause this sort of 'back and fourth' of what's good and
what's bad. But on the subject of acetone, I have worked in places with bacterial waste water management and occasionally we would have to 'feed the
bugs' which meant pumping 275 Gal of acetone into the sewer which made its way to the microbiological processing area and caused a proliferation of
those beautiful sewage eating microbes.
@ franklyn-
If you honestly think that anything not 'OTC' in terms of a solvent is not realistic for the chemist at home I would think you're missing the whole
point of chemistry at home or your intentions/aspirations are entirely different than my own. Granted I didn't do it much but I managed to run
reactions in the nitrobenzene that I made (definitely not OTC). Not the most elaborate of choices but I was working on making diethyl carbonate for a
solvent as well, though I never perfected it I could produce usable quantities of ethylene carbonate which I just never converted to the next step of
things. Besides, what you consider OTC is of course different than what others in other countries call OTC and what others have access to despite it
not being OTC in their area, perhaps they have run across a bottle of a particular solvent.
Nevertheless, I find this topic interesting. I've said it before, I have a solvent fetish, I think they are some of the most interesting aspects of
any chemical reaction and for that reason alone I think it's interesting to learn about some of these newer solvents being pushed or new takes on
older solvents. If only to see where the field is heading but also for the other benefits that I have mentioned before.
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chloric1
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| Quote: | Originally posted by pantone159
I was told once that hexane is significantly more toxic than pentane, and for this reason I bought pentane at the time instead of hexane. The problem
here with that, is that ambient (outside) temperatures often enough exceed the BP of pentane (36.1 C), so the volatility is a problem.
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@pantone-IIRC, Hydrocarbons with even number carbons are significantly more toxic than odd number hydrocarbons based on how this products are
metabolized. For the life of me, I wish I could recall the source. Also, I had the same volatility problem with DCM(BP 34°) and I live much more
north than you(Indianapolis) where summer temperatures typically reach or exceed 35°C less than 10 times a year! The outside temperature only needs
to approach BP as many sheds, storage facilities, garages, can easily exceed reported temperatures. Then again many liquids evaporate easily even 10
or 15°C below there boiling point.
@everone else-Big chemical corporations pushing "green" solvents reminds me of what happend nearly 20 years ago. Sometime during the late 1980's Dow's
Patent rights on freons where about to expire. At the same time the media reported new "scientific" findings that freons where eating holes in the
ozone layer. With all the new legislation that
passed in the 1990's you could only use R-134 and its cogeners which costed much more. And don't forget after 1996 a large number of chlorinated
solvents where determind as "hazardous" to ozone. Hence you could find 1,1,1-Trichloroethane for the bargain of $300 per gallon. I can't wait until
the UN gets it's carbon tax!
Fellow molecular manipulator
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franklyn
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A related thread here _
http://www.sciencemadness.org/talk/viewthread.php?tid=10529
.
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Mush
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Cyclopentyl methyl ether
https://www.manufacturingchemist.com/news/article_page/A_new...
Dioxolane
Attachment: BASF_Brochure_Dioxolane.pdf (592kB)
This file has been downloaded 284 times
[Edited on 9-5-2020 by Mush]
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clearly_not_atara
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You bored lately, Mush? You've revived a lot of threads.
[Edited on 04-20-1969 by clearly_not_atara]
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njl
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This is a topic I'm very interested in. Whenever I get to thinking about solvents I feel like I'm at a slumber party talking about cute boys  .
I want something immiscible with water, forming an azeotrope like toluene, as available as ethanol, not flammable, and low boiling. Maybe I should do
some reading about solvent design...
Side note: I had to use DMSO in pH sensitive coupling and the smell was UNREAL. I've worked with smelly stuff before. I've had my fair share of
phosgene puffs to the face. But the smell of satanic rotten cabbage/garlic fermented in a butthole that persisted for HOURS has been the worst.
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fusso
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Quote: Originally posted by njl  | | I want something immiscible with water, forming an azeotrope like toluene, as available as ethanol, not flammable, and low boiling.
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DCM?
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clearly_not_atara
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Depending on the nucleophilicity of your reactants 1,2-dichloroethane might be suitable. The azeotrope is 13 C deep.
[Edited on 04-20-1969 by clearly_not_atara]
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mackolol
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| Quote: Originally posted by njl | This is a topic I'm very interested in. Whenever I get to thinking about solvents I feel like I'm at a slumber party talking about cute boys .
I want something immiscible with water, forming an azeotrope like toluene, as available as ethanol, not flammable, and low boiling. Maybe I should do
some reading about solvent design...
Side note: I had to use DMSO in pH sensitive coupling and the smell was UNREAL. I've worked with smelly stuff before. I've had my fair share of
phosgene puffs to the face. But the smell of satanic rotten cabbage/garlic fermented in a butthole that persisted for HOURS has been the worst.
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It's because dimethyl sulfide, which is dissolved in trace amounts in DMSO is evolved while heating.
| Quote: Originally posted by mackolol |
When I worked with trace amounts evolved from slightly impure DMSO it smelled like really bad sulfur SHIT.
Good way for neutralisation of Me2S is to put exhaust pipe to dilute solution of hypochlorite. Now for me it works very well and doesn't produce any
odor. |
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B.D.E
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| Quote: Originally posted by pantone159 | | I was told once that hexane is significantly more toxic than pentane, and for this reason I bought pentane at the time instead of hexane. The problem
here with that, is that ambient (outside) temperatures often enough exceed the BP of pentane (36.1 C), so the volatility is a problem.
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I use n-heptane instead. it has its own pros and cons:
pros:
*allegedly less toxic than n-hexane.
*not very volatile
neutral:
*high b.p(y(~98.4C)
cons:
*b.p is very close to that of water(somewhat problematic in extractions).
(it is of course phase separating from water. so in general it's not that big of a deal).
[Edited on 12-5-2020 by B.D.E]
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njl
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@fusso I have about 400 ml of dcm left, it's pretty hard for me to get but very precious
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G-Coupled
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| Quote: Originally posted by njl | | @fusso I have about 400 ml of dcm left, it's pretty hard for me to get but very precious |
DCM is one of the most useful solvents IME - are there any solvents/reagents that seem easier than 'normal' for you to acquire where you are, as a
matter of interest?
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njl
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I agree dcm is great. I bought a liter for pretty cheap but now my only way is to distill from paint thinner which yields about 300 ml for 20 USD and
a couple hours of work. I can get drain cleaner sulfuric acid so ethers may be an option, but I'm not big on straight chain ethers just because of
peroxide/flammability issues in storage. I have used dioxane a lot but that's soluble in water. To answer your question, Acetone, "Denatured alcohol"
(~60/40 ethanol/methanol), "Mineral spirits" (I'm guessing medium length alkanes), and I think I've seen naptha but I've never looked into it.
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DavidJR
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| Quote: Originally posted by njl | | I agree dcm is great. I bought a liter for pretty cheap but now my only way is to distill from paint thinner which yields about 300 ml for 20 USD and
a couple hours of work. I can get drain cleaner sulfuric acid so ethers may be an option, but I'm not big on straight chain ethers just because of
peroxide/flammability issues in storage. I have used dioxane a lot but that's soluble in water. To answer your question, Acetone, "Denatured alcohol"
(~60/40 ethanol/methanol), "Mineral spirits" (I'm guessing medium length alkanes), and I think I've seen naptha but I've never looked into it.
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Dioxane is carcinogenic, and also can't be used for preparing Grignard reagents (Schlenk equilibrium). So it's not a replacement. THF is much safer
than diethyl ether, so it is my preferred ethereal solvent. It still has issues with peroxides.
I've heard about 2-MeTHF which is renewable and has some technical advantages over THF, but I haven't found anywhere selling it at a reasonable price.
It still forms peroxides.
CPME (cyclopentyl methyl ether) is even more interesting to me as it apparently doesn't form peroxides, is water immiscible, and works well for
organometallic chem as well as liquid-liquid extraction and azeotropic drying. But again, I can't find it anywhere at prices that aren't obscene.
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