Jor
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benzene uses: suggestions?
After having done the nitrobenzene synthesis, I see no more uses for my benzene, except complicated organic synthesis in wich I have no interest.
Do you guys know if it has any other insteresting uses in inorganic chemistry?
If not, I will dispose of it, at the chemical waste facility, because I don't see why I would keep a flammable and carcinogenic (=extra storage
hazard) material wich I don't use.
[Edited on 29-3-2009 by Jor]
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turd
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If nothing else, it's still quite useful for washing glassware.
Otherwise... AFAIK, there's ferrocene like sandwich complexes, but with benzene instead of pentadienyl. (If you consider that inorganic chemistry.)
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woelen
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Don't throw away chemicals for which you do not have a use right now. IIRC you only have 150 ml or so of benzene and is that really such a burden to
keep around? If you dispose of chemicals now, you may regret things very much in the future, especially because it only is a small amount which can be
kept in a simple gass 200 ml or 250 ml bottle. Things would be different if it were a huge amount, but having such a small bottle around, I do not
really see a problem 
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garage chemist
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Don't dispose of the benzene! It is to be expected that acquisition will only become harder in the future- it is already next to impossible to buy
here.
There are many useful things you can make from it- just a few examples:
- bromobenzene (excess of benzene + bromine and a tiny amount of AlCl3, requires fractional distillation to obtain it pure), good for grignards
- chlorobenzene (useful for nitration to 2,4-dinitrochlorobenzene, a precursor for 2,4-dinitrophenylhydrazine, an analytic reagent for ketones and
aldehydes, and also for hydrolysis to 2,4-dinitrophenol, useful as an oxalate ester for chemiluminescence)
- anthraquinone from benzene + phthalic anhydride (synthesis is available on orgsyn, I think)
- acylation with acyl chlorides or anhydrides
- alkylation with alkyl halides, e.g. with 2-bromopropane (from IPA and HBr) to cumene, which can be used to make phenol
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Jor
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Yes woelen I agree, but I have MANY small bottles around. Many chemicals I have are toxic (heavy metal salts, some toxic organics, etc) . I like to
keep my storage to a minimum, because the less chemicals you have (especially the ones with skulls on the bottle, as 'common' people are not used to
these anymore, as not OTC product has a skull)) the less likely police will do anything IF you get a visite (this is a thing wich every home chemist
should expect, you can influence the chances of it yourself, by not making odours, not buying large amounts or restricted chemicals, etc). I am not
too afraid that I will ever get police at the door, as I think I am a well organised, relatively safe home chemist, but I always want to be prepared,
I always clean well, etc.
Second, in case of a fire, I want to have an as small amount of toxins/oxidisers/flammables around, so that chances are lower that insurence won't
pay, as that would be a very bad thing.
Third, i don't have that much room anymore, so I dont want chemicals all over the place. I plan to remove useless chemicals from my lab the following
months. I have some wich I am going to remove to a waste facility, like metol, very old oxidised CuCl (wich has formed a rock-hard solid green block,
impossibly to get out), and possibly malic acid. I am thinking of getting rid of the benzene as well. For any of these chemicals I see no use for now
and in the future. Ofcourse, with every one of them, I will keep a small amount (10 grams), and maybe 20-30ml of benzene, incase I want to do
something really bad.
Benzene is just something wich is a carcinogen, and I see no real interesting uses for it now and in the future. Ofcourse I may regret later that I
didn't keep it for 1 experiment, but that's a risk I take, the reward is extra room (wich i dont have a lot of) and less storage.
I am always trying to store things as good as possible, and I never want useless things (at least for me) around. For example, I can now buy 1L of
CCl4 for 30 EUR (very cheap), and I;m very interested in this chemical (good for dissolving many covalent, highly reactive, metal compounds), but I
simply don't want a liter around, wich is a lot of COCl2 in a fire!
I think this is also my responsibility. I live with my parents and brother/sister, and I think that i should minimize the risks to a minimum. If i
would have my own house, I would ofcourse keep the benzene!
But woelen, how do you do this then? AFAIK, you have much larger quantities of chemicals (Also recently bought 1L Nitrobenzene right?). Do you never
remove useless chemicals?
Otherwise the quantities will keep going up right? Buying but nor removing will have that result, especially when working mostly on small scale, like
me and you.
However, garage chemist, you got me interested, as I might want to make some 2,4-dinitrochlorbenzene.
Is anthraquinone interesting? I have phthalic anhydride...
I am happy to donate the benzene to other hobbyist, however, I do not know is it is responsible to ship such a thing, at least not international.
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Magpie
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Jor I think woelen and GC have presented good arguments for why you should keep that benzene. But I can also sympathize with you. Your reasoning is
sound and very responsible. Ultimately it is a personal decision.
I keep an inventory of the chemicals I have and actually feel good every time I can add one. I now have 207 different chemicals and minerals. It is
only now that I ususally have all the reagents that I need to perform some new experiment.
Benzene is a key organic precursor and as GC says may be getting increasingly difficult to obtain. You are a young man and just because you see no
need for it today does not mean that you might not want it badly in the future, especially if your interests broaden into the field of organic
chemistry. You have thrown yourself into this hobby with great gusto, learned much, and accomplished much. I would be surprised if it is not a
lifelong hobby for you.
Taking a perfectly good chemical to a hazardous waste dump, although a responsible act if you must, is still a waste of a valuable resource.
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Jor
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Thank you for the compliments ! 
I think you guys are convincing me 
I will think about it.
I am definately getting more and more interested in organic, but I find that a more hazardous thing to perform at home than inorganic. Especially the
waste produced is harder to handle and dispose of. I do organic syntheses, but not much.
Still my absolute favorite thing to do is making all kind of metal complexes at a gram scale or so, followed by test-tube scale 'just observe'
reactions.
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JohnWW
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There are other things that benzene can be used to synthesize, besides nitrobenzene, as well as being a nonpolar organic solvent:
(a) Mild chlorination or bromination in the prsence of Fe will give chlorobenzene or bromobenzene in the first instance, which can then be hydrolysed
to produce phenol (a source of further phenyl compounds), or otherwise substituted to introduce phenyl groups into compounds. (Formerly used as an
intermediate to produce DDT insecticide, now largely banned for agricultural purposes).
(c) Furher chlorination will give p-dichlorobenzene, a solid insecticide used mainly in mothballs.
(d) Chlorination with UV light will produce an isomeric gammexane (benzene hexachloride) mixture including Lindane, used as an insecticide, although
because it is toxic to non-target species its use as an agricultural spray is mostly prohibited (like DDT).
(e) Sulfonation with SO3 gives benzenesulfonic acid.
(f) Friedel-Crafts Alkylation or Acylation with an alkyl or acyl chloride and AlCl3 gives an alkylbenzene oe acylbenzene, including toluene which can
be oxidized to benzyl alcohol, benzaldehyde, or benzoic acid, with appropriate oxidants.
(g) Benzene reacts with certain transition-metal cations under certain conditions to give pi-complexes, usually in which the metal atom is between two
benzene molecules. Thse can be used, in non-polar organic solvents, to synthesize further organic transition-metal compounds.
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vulture
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| Quote: |
Benzene is just something wich is a carcinogen, and I see no real interesting uses for it now and in the future. |
There's more benzene in any petrol consuming car than the quantity you currently possess. Keep it.
One shouldn't accept or resort to the mutilation of science to appease the mentally impaired.
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woelen
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Jor, I decided not to buy the liter of nitrobenzene, as I have no other use for it besides experimenting with the Kerr cell. I asked and the minimum
quantity I can take is 1 liter.
I also have MANY small bottles around and a few larger ones. I think I now have over 400 chemicals, the great majority of them in less than 100 gram
quantities, but I do not think that is a real problem. I do not have many organics though, I only have some of the common solvents and some solids
like citric acid, malic acid, malonic acid, oxalic acid etc.
I actually acquaire small quantities of chemicals, even if I do not have a direct use for them. In this way I even acquired 20 grams of Na2HAsO4, and
although I do not have a use for it now, I know it will be VERY hard to obtain stuff like that in the future and having such a small bottle of 20
grams (orignally 25 grams, but it was sold to me as 20 grams second hand chemical) is not a problem for me. I only stay away from big quantities like
liters or kilos. I once was offered 2.5 liters of 30% oleum, but that I decided not to take. Such a big bottle of such an intensely corrosive chemical
is too much for my home lab (and besides that, shipping this stuff also is a risky thing). I now have 200 ml of 20% SO3 and that is enough for me.
I am, however, very careful in how I store my stuff. Highly volatile and flammable chemicals I do not store in my lab, but I store them in our garage,
which is very well ventilated especially if we have a breezy day.
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Magpie
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| Quote: |
In this way I even acquired 20 grams of Na2HAsO4, and although I do not have a use for it now, I know it will be VERY hard to obtain stuff like that
in the future
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Woelen I also was recently looking for an arsenic compound with which to verify a qualitative analysis procedure. None of my usual sources had any.
In fact I could not find a source. Then I remembered the mineral collectors. Looking on eBay I found a great deal of As2S3 (orpiment) and realgar
for sale at reasonable prices. So I bought a very small chunk of orpiment (1cm x 1cm x 0.5cm). After all it's just a rock.
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hellfire23
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Benzoyl peroxide?
Is that an explosive, I don't know but you could try it.
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benzylchloride1
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Benzene can be used to produce tetraphenyl tin which is an interesting organometallic compound. Two routes are available; the benzene will have to be
brominated to produce bromobenzene. The bromobenzene can then be turned into a Grignard reagent or an organosodium reagent. This is then reacted with
tin (IV) chloride to produce tetraphenyl tin. Tetraphenyl tin is used as a phenyl group transfer reagent in inorganic synthesis.
Amateur NMR spectroscopist
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watson.fawkes
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If you're worried about the health safety of your benzene in storage, put its bottle inside another bottle. The vapor concentration in the outer
bottle slows the leakage from the inner bottle.
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Panache
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Its makes a great acne treatment when mixed with a surfactant into a cleanser, ridiculously expensive to purchase for such a nothing chemical, but hey
that's cosmetics.
With the hysteria over benzene's toxicity you could probably rob a bank by threatening to pour some over the teller unless they open the safe.
Around 1% of petrol here in Australia is benzene so i'm effectively breathing some in every-time i inhale, along with some asbestos, PCBP's and dog
hair.
The point is it's not so dangerous as to warrant wanting to dispose of it for safety issues, its hardly an acute toxin.
edit-shit i just read the other posts (whoops) i assumed someone would have mentioned its value to azeotrope out water from so many things its
absolutely invaluable for this purpose alone. PTSA is easy to make but notoriously difficult to dry, useless wet, but a super-great (such a german
adjective HA!) catalytic lewis acid for esterfications. Benzene azeotropes out all its water easily and quickly leaving the small amount of PTSA in
your round botttom, just add your other reagants and voila, and who doesn't mind a nice esterification now and then.
[Edited on 2-4-2009 by Panache]
[Edited on 2-4-2009 by Panache]
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