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Author: Subject: Recommendations for "Safer" Reactions
Oncorhynchus
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[*] posted on 14-9-2022 at 17:06
Recommendations for "Safer" Reactions


I understand that there are always risks associated with this hobby, but what are some relatively safe reactions and syntheses one can carry out without a proper fume hood? I'll be working out of a garage with a fan (don't want to work outside and have to deal with the neighbors) and am not opposed to buying a respirator at some point. I'd mostly like to avoid some of the harsher solvents and reagents that could pose serious inhalation risks.

By "safe", let's say anything under 4/10 with 1 being a simple aqueous (or ethanol-based) extraction and 10 being anything involving liquid bromine, carcinogens, or high explosives. For reference, I've previously made phenol from hydrolyzed acetylsalicylic acid, nitric acid from KNO3 and sulfuric acid, and a very small scale chloroform synthesis.
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[*] posted on 14-9-2022 at 18:37


Which area of study interests you the most?

This is the organic section let me toss out a few i've done

1,4 dioxane is an easy one if you have the proper glassware,
keep the boiling flask below 150c to prevent excessive tar and foam.

Sodium metal via alcohol is one I love.
Potassium metal is another good one.

Extracting and isolating colored compounds from fruit and vegetable is a difficult one. Ive had mixed results. Most poor

sodium acetate is fun to play with

Acetone from calcium acetate.

calcium carbide from CaOH and carbon. CaCO3 can also be used
Acetylene from calcium carbide




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Deathunter88
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[*] posted on 14-9-2022 at 20:55


Quote: Originally posted by Oncorhynchus  
I understand that there are always risks associated with this hobby, but what are some relatively safe reactions and syntheses one can carry out without a proper fume hood? I'll be working out of a garage with a fan (don't want to work outside and have to deal with the neighbors) and am not opposed to buying a respirator at some point. I'd mostly like to avoid some of the harsher solvents and reagents that could pose serious inhalation risks.

By "safe", let's say anything under 4/10 with 1 being a simple aqueous (or ethanol-based) extraction and 10 being anything involving liquid bromine, carcinogens, or high explosives. For reference, I've previously made phenol from hydrolyzed acetylsalicylic acid, nitric acid from KNO3 and sulfuric acid, and a very small scale chloroform synthesis.


You cannot place risk in a 1-10 scale, and most of it comes down to a personal judgement. In my opinion there are very few experiments that CANT be performed due to absolute risk in an amateur setting (a random example might be making multi-kg quantities of HCN in a densly populated neighborhood).

For example, I would be perfectly happy with working with elemental bromine in my garage with a box fan blowing out of a window. Even if the worst happens and I drop the entire flask of liquid bromine, I trust myself to hold my breath long enough to leave the garage, where I can then open the garage door and it would all be gone in an hour. For someone else they might want to be wearing a full face respirator and working outdoors, and for others they may not want to do this at all. But at the same time I am always cautious when I move around a 4L glass bottle of say, acetone. If I drop it that's a LARGE puddle of flammable liquid that is going to take a long time to evaporate, giving off vapors, which a spark from a light switch or the water heater will ignite. Therefore for me dropping the bottle of acetone is worse than the vial of bromine. You may think differently, which is totally fine since everyone has their judgement.

I'll note that two areas you should place extra attention are cumulative poisons and carcinogens.

Do you really need to be scared of a stoppered flask of a chlorinated solvent you'll use for one extraction when automotive techs spray cans of brake cleaner daily, and DCM up until very recently is widely used in multi-gallon amounts as a paint stripper?

Do you really need to make carcinogens like chromates off-limits if it is used in consumer products like gun-blueing or electroplating kits, or do you trust yourself to know enough compared to the averge Joe to work with it safely?

These thoughts are genuine questions everyone in this hobby should ask themselves to develop your own guidelines, which can change as you gain more experience. You'll find that most "dangerous" procedures in amateur chemistry actually has many parallels in other hobbies, where people have found ways to work with it safely.

Amateur artists have found ways to work safely with HF and flouride compounds to etch glass
Amateur fireworkers have found ways to work safely with shock and friction sensitive mixtures
Amateur photographers have found ways safely with dichromates to develop photographic plates
Amateur electroplaters have found ways to work safely with highly toxic cyanide salts for gold plating
Amateur biodiesel makers work with concentrated sulfuric acid and other caustic chemicals on a relatively large scale
ETC
ETC...

I would argue approaching each of these from a chemistry background actually makes them safer. Just some food for thought.
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woelen
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[*] posted on 14-9-2022 at 23:01


I myself do quite a few experiments with 'dangerous' chemicals. You can find many of these experiments on my website. The problem is not how dangerous a chemical is, but how you treat it.

There are immediate dangers, like corrosiveness, explosive properties, extremely poisonous properties and there are more elusive dangers, such as long term exposure to minute quantities, due to pollution of your living environment, or the slow corrosion of vital parts of your house infrastructure, due to improper storage of corrosive volatile chemicals.

I myself are quite precise in cleaning up things after experimenting. Just do some experimenting with KMnO4 and inspect your workplace, after you have done the experimenting. You'll see little purple specks averywhere. This is very instructive to see the risk of long term exposure. Not a real issue with KMnO4, but what if you have the same with lead nitrate, lead acetate, or beryllium salts? Another risk of pollution is the bubbling of metal salt solutions, which can produce aerosols with tiny droplets, containing metal salts. One example of that is my making of mercury nitrate, by dissolving some mercury in warm nitric acid. This reaction can be quite vigorous, producing brown gaseous NO2, which is spewn out of the test tube. Most people acknowledge the risk of the plume of NO2 and use good ventilation of their room. But what people do not acknowledge is that tiny droplets of liquid are taken with the gas, which contain water, nitric acid and mercury nitrate. The water and nitric acid almost immediately evaporate and a tiny particle of solid mercury nitrate remains, which settles as dust on the floor, on furniture, on fabric. The NO2 and nitric acid vapor quickly are gone. If you just open the door and ventilate, then a few minutes later these nasty gaseous products are gone, but the mercury salt remains, polluting your living environment! So, with that kind of reactions I always use a paper tissue, with which I loosely cover the flask or test tube, such that the gases can escape, but the little droplets are absorbed. A nice pluck of wadding, used as a loose stopper also works fine.

The direct risk of certain chemicals is less of an issue for me, when I do experiments with them. You have to be sure, however, that you know BEFORE you do the experiments, that there are such direct risks. E.g. I made extremely sensitive mixes of NaClO2 and red P, or combined peroxo/ammonia complexes of chromium. These things do want to explode or ignite, just by looking angrily at them. I even made chlorine azide! But knowing the risks of these kinds of things, I only made them in mg quantities (certainly less than 50 mg), used PP-test tubes instead of glass and avoided confinement of the solids. I had a few little accidents, but the precautions I took assured that nothing more serious happened than destroying a PP-testtube, or having a spoiled spatula. If I really need to use glass test tubes, then I wrap them in a towel, which I keep in my hands. A 50 mg explosion then does not harm my hand, it only shatters the test tube and causes some cuts in the towel if something goes wrong.

Only very few compounds I really would avoid, the ones which introduce unmanageable risks, such as nerve gases, hypergolic explosives, or severely radioactive materials. To my opinion, these are beyond home chemistry. I have no such compounds, and also will never have them, even if I could get my hands on them.

[Edited on 15-9-22 by woelen]




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clearly_not_atara
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[*] posted on 15-9-2022 at 07:29


>OP asks for safe reactions
>first reply suggests making potassium metal


Stay reasonable SM :D

I would actually suggest the Fischer esterification of methanol and oxalic acid, this produces dimethyl oxalate, it's a pretty simple reaction, and it can then lead to a variety of methylation reactions or, probably more fun, transesterification with phenol to produce the chemiluminescent diphenyl oxalate. The second step is probably harder, but the esterification of methanol with oxalic acid has been documented here by a few people.

[Edited on 15-9-2022 by clearly_not_atara]




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Oncorhynchus
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[*] posted on 15-9-2022 at 15:27


Thanks for the responses so far -- the dimethyl oxalate idea sounds like it could be a fun one for me. I should have mentioned in my original post that I do have a BA in chemistry and a MS in environmental/analyical chemistry, so I'm quite familiar with general lab safety protocols and chemical handling.

My main goals with this were A) to get a few ideas of organic reactions and reagents that are generally easy to handle safely and B) to see which reactions and reagents are generally too difficult/dangerous/corrosive to be handled in a garage. I'm well aware that minute exposures to most chemicals doesn't pose a huge health risk, but I also don't want to damage or contaminate my rented space.
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[*] posted on 15-9-2022 at 16:00


Making chlorobutanol from chloroform and acetone is really easy and it's a super useful drug for sedation, antiseptic, local anesthetic and water sterilization. Although if you do make it I wouldn't suggest taking it orally as the effects lasted for days for me, altho it is pretty mild.



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[*] posted on 15-9-2022 at 18:38


Copper aspirinate is a good one.
ASA --> salicylic acid --> methyl salicylate is good, too.




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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[*] posted on 16-9-2022 at 01:38


A lot of compounds could be handled safely but that requires some experience. Try to get as much experience as you can with more safe compounds or small scale before handling more dangerous compounds.

Without a fume hood, you can handle (on a normal scale) carboxylic acids, HCl up to 38%, a water solution of HBr, cold or warm H2SO4 up to 98%, and not fuming HNO3. Working with gaseous HCl/HBr, fuming (or very hot) sulfuric or nitric acid will require a fume hood.

As a cheap substitution for a fume cupboard you can use a construction fan with a wide hose:
http://www.sciencemadness.org/talk/files.php?pid=650686&...

I would say that stand and clumps are a more important part of a laboratory than a fume hood. You can work safely only if you can fix everything safely.

These compounds could be handled safely without a fume hood:
different alcohols and ketones, aldehydes, aliphatic ethers, esters of carboxylic acids, xylene, toluene, ammonia, dichloromethane, SO2, acid and alkyl chlorides.
Some of them are not very pleasant but at least you will recover well.

Boiling of acids will require distillation apparatus and/or a good fan. The same about the reaction of HNO3 with some compounds which generates NO/NO2. There are separate topics here dedicated to NO/NO2 mix absorption. Generally, you can work with this staff without a fume hood. Chlorine is quite manageable in small quantities as well.

With some experience, you will be able to handle liquid Br, but I would say it is close to the "border".

On the other side of the border, there are things that definitely require a fume hood. I would put here things like CO (but you can also buy a detector and put it into your lab), HCN (but I know some members do experiments with gaseous HCN on a test-tube scale just outside, but I think it is no novice-friendly compound), H2S, HF, CCl4, nitrobenzene, hydrazine, BF3, alkyl cyanides, SOCl2, SO3, PCl3, SbCl5, AsCl3, etc.
Also, I believe it is quite possible to work with H2S, CCl4, mercury, chlorosulphonic acid, or CrO3 solution in concentrated HNO3 (glassware cleaning) without a fume hood I would not do so.

There is a separate group of compounds that are "carcinogenic". As a rule, most people who die from cancer are not home chemists. Many factors play, but everybody agrees it is not good to breathe, for example, alkyl bromides or benzene on daily basis. Everybody produces zillions of cancer cells every day and it is the duty of our immune system to destroy them and the immune system of most people does it quite well. But it is no good to push this system to its limit anyway, so try to minimize contact with "mild" carcinogens and try to avoid "strong" carcinogens without a good reason. Try to use a "benzene" rule - if you can smell it - improve your ventilation.

For compounds not mentioned here you can always check sciencemadness wiki, the "Safety" part.

[Edited on 16-9-2022 by teodor]
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[*] posted on 17-9-2022 at 01:58


I'd like to add that there are some well-written and illustrated books dedicated to the area of organic experiments with only basic equipment. For example, Louis Fieser, "Organic Experiments". It is very well fitted for the home lab.

If one would try to find a similar book just for inorganic chemistry I would say "Microscale Inorganic Chemistry" by Szafran, Pike and Singh is very similar in its conception.
There are many other good books with detailed descriptions and step-by-step approaches, like Palmer "Experimental inorganic chemistry" or Noyes "Qualitative Chemical Analysis" and more.
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[*] posted on 17-9-2022 at 05:20


Quote: Originally posted by Oncorhynchus  
I understand that there are always risks associated with this hobby, but what are some relatively safe reactions and syntheses one can carry out without a proper fume hood? I'll be working out of a garage with a fan (don't want to work outside and have to deal with the neighbors)

There are too many options for a simple answer,
I suggest that you watch a few YouTube videos and read a lot here on SM,
if you find something that interests you,
post a link to it and ask for specific advice here on SM
you will get good advice here.
I have found folk here to be incredibly helpful and knowledgeable.

In my case, the most danger comes from complacency,
performing 'dangerous' experiments I research, plan and take appropriate precautions (usually),
it is when I'm doing mundane things that I am rather lax with precautions and put myself at risk.

A significant risk factor is scale : smaller scale = smaller risk
not just during the experiment but also during storage.
Test tube scale is adequate for most experiments.

Keep a log book - a reference for yourself and 'evidence' of academic rather than nefarious intent.

Welcome, take care and enjoy.





CAUTION : Hobby Chemist, not Professional or even Amateur
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