testimento - 19-10-2013 at 12:04
I have became aware that benzene, toluene, xylene and benzyl derivatives are sometimes scarcely available, because of several reasions: they are not
needed in public, the draconian politics ban everything that could be harmful in case of misuse, and due to illicit use of some specific items.
Toluene seems to be somewhat available as paint thinner and different solvents, though this is being heavily substituted with xylene, acetone and
other products, and the leftover sources are becoming unbearably expensive. Xylene is quite freely available, then. Could xylene be turned into
toluene, or could it be substituted in syntheses?
Benzene is a straight no-go: it is the behemoth himself of all the carcinogens. Benzoic acid and its salts are a single source via pyrolytic
hydrolysis and quite effective as long as the item itself would be available. I haven't been able to track a single OTC source for this, except for
chemical dealers, of course.
Benzyl alcohol is used as perfumerant and aromatic compound and carrier, and it can yet be found in some paint thinners and solvents, but it is quite
an expensive as it is. This one is something i'd be especially interested at this moment, needing few quarts for one process.
A source often overlooked is the pyrolysis of plastics. Plastics of every type, PE, PP, PS, PET, primarily, which consists of 90% of all plastics
used. I performed a test with 5kg batch of mainly polystyrene, and I acquired about 4.5 liters of yellow liquid, which I am in still need of
fractioning to find out what it has, but the temp range of it was between 0-250C, and it partially(1-3% max) paraffinates upon standing, so it
contains some heavier chains too. The smell is overwhelmingly aromatic.
About the plastics overall, this topic is of an interest I'd be probably writing an article. I have a 80-liter pyrolysis distillery apparatus which
I'm gonna put into good use for this project. An example of this process is 30:70 PS
E mixture of plastics, catalyzed by addition of 10-20% of volume with zeolite (optimum ZSM-5, otherwise the OTC for pool clearing agent
will substitute) will produce major amount of toluene, benzene and styrene. It can be processed without zeolites, but the yield is 30-50% lower and
less aromatic.
According to several PDF documents(I'll link later when I find them first from my archives), common plastics an car tyres produce an oil, which
contains 30-70% by weight of aromatic compounds, mainly benzene, toluene, styrene, ethylbezene, phenol and common hydrocarbons. The plastics may show
up a major source of aromatic compounds if the draconian laws will soon cover all the common solvents.
Some countries' gasoline contains up to 15% toluene(stated in local MSDS specifically), which can be fractionated.
[Edited on 19-10-2013 by testimento]