fritz - 7-12-2003 at 12:02
Did anybody here ever some research about dichlorvos (DDVP, DVDP; 2,2-dichlorovinyl)-dimethylphosphate)? I was not able to find out very much about
this substance. The only informations I could find were about some physical and physiological datas.
I tried to obtain DDVP from strips made of a felt-like substance which were drenched whith DDVP. I extracted these strips first whith gasoline but
DDVP seems to be immiscible whith DDVP. So I tried Acetone Which did well. To tried to obtain it in pure form (I have no apparatus for
vacuum-destillation which is necessary for destillating DDVP) I mixed the solution with gasoline (ratio 15:85) and separated it in a
separatory-funnel. Now I have a very viscous liquid which is very difficult to sparate from the acetone/gasoline mixture. Does anyboy know something
about DDVP? May the liquid I have separated be pure DDVP? Or is it possible that this subtance polymerized?
My first experiment to obtain it in pure form was pressing the pads but there was remining to much of the DDVP in the strips so I started with
extraction. In the saparating step I tried first to use water instead of gasoline but it was not possible to dry the resulting liquid whith
Calciumchloride (The Calciumchloride solves in the liquid)
DDTea - 7-12-2003 at 14:08
DDVP (that is the former USSR name-- it is more commonly known as Dichlorvos) is one of many Organophosphorus Insecticides. It is moderately toxic by
ingestion -- 80-120 mg/Kg is the LD50 for Rats. It doesn't seem to be a very aggressive Pesticide against humans, especially considering that the
primary means of exposure (generally speaking) would be inhalation. All I can find on the Material Safety Data Sheet for it is that, "prolonged
exposure may cause irritation." However, on E&W Forum, I was considering additional reactions to put OP pesticides through to increase their
toxic action...
Still, Dichlorvos doesn't look like it would lend itself well to such reactions. If your goal is to find a very aggressive OP Pesticide, I would
suggest Tetraethyl Pyrophosphate. However, that being difficult to obtain, Malathion is good. There was a big issue a few years ago that Malathion
could oxidize to toxic Malaoxon, which is mildly poisonous to humans by inhalation. Of course, this reaction could be deliberately done in our Mad
scientist home-labs. On top of that, Malathion is readily available (it is considered one of the safest OPs) in 50% concentrations.
Alternately, you can skip the OP pesticides altogether and go straight for the Carbamates. They are also anti-cholinesterase agents and their short
term action (less than 12 hour) can be very severe. But, the carbamate molecules do not bond as permanently to the cholinesterase molecule, so they
aren't very persistent in the body.
Well, I veered off topic quite a bit here, but I hope I presented something useful. 
fritz - 8-12-2003 at 04:04
o.K. I actual were searching about general chemistry informations about dichlorvos (I forgot to add this name in my list of possible names for this
substance) but nevertheless thank you for your informations and suggestions!
My actual intention is experimentating with some substances wich belong to the class of the OP. Dichlorphos was just a substance were I thought of it
might be easy to obtain and get in a pure form without much complications. I also have access to parathion ( Ethyl-parathion, E-605,
O,O-Diethyl-O-(4-nitrophenyl)-thiophosphate) but my only experiments with this stuff were trying to get this dammned blue dye out of the solution (I
tried some kind of solumn-chromatography with chalk as stationary-phase) this failed. So I had to look for other materials for doing some researchs.
I want to try (when I ever get some OP-compounds in a more or less pure form) if it´s possible to alter some substitutes in the structure to get
substances which might have a greater potential or which might have some other intresting characteristics (like some alternative ways of incorporation
or just an increase of some special way of incorporation)
DDTea - 8-12-2003 at 14:01
Might I ask where you procured Parathion 
.
One experiment you may want to try, if you are feeling particularly adventurous, is to oxidize Parathion to Paraoxon-- that is, replace the P=S group
with a P=O group. This reaction normally occurs in insects, and this is aids in their poisoning. However, while Parathion is in itself very toxic to
people, Paraoxon is even moreso.
The leaving group of most OP pesticides tends to be pretty unreactive-- in the case of Malathion (the only one I can remember off the back of my
head), a Dicarboxylic acid. Naturally, they won't want to have something like -F or -CN bonded to the Phosphorus, as this would make it very
reactive and thus very poisonous... Nevertheless, a common reaction in the production of Nerve Agents is to change the leaving group of an OP. I
don't know specifically how this would be done-- I imagine by the reaction with an Acid such as HF or HCl ( just speculating here ), to form the
corresponding acid fo the leaving group and, ideally, to bond the -F to the Phosphorus.
fritz - 9-12-2003 at 14:01
Yes, Samosa, this is exactly what I thought of! But this steps of research seem to be far away since I have no idea how to purify my parathion
respectively I´m not sure if that substance I got from my pesticide strips is the desired DDVP.
Another problem with comes with such experiments is decontamination. I first tried hypochloride/hydroxide solutions (suggested in nearly every
information about CW- and what´s not good for CW might realy deadly for `harmless` pesticides
-harmless of course compared to CW! I´m not crazy or tired of life!) the problems with this solution when treating my waste/glassware
with it is it leaves a realy nasty sticky mass back on all surfaces. So I went over to use permanganate/hydroxide solutions. I think the effect of
detoxification shall be similar. And this sln. leaves a brownish mass (MnO2-hydrate I guess) which could be easily rinsed. And after roughly cleaning
the so treated flasks, tubes, etc. I let them stand overnight with HCl (20%). So no MnO2-staines leave on the glass and the produced Cl2 will oxidize
every rest of OP which might have been on the surfaces after treating with the permanganate. (This treating of glass with first permanganate/hydroxide
and then with HCl is a very exellent and effective way of cleaning it from persistent organic residues!!)
When I treated my DDVP-sln with dec.sln. I always noticed some kind of smell (different from that of DDVP itself!) it´s slightly sweet and
unpleasant! I first was afraid of having created Vinylchloride which is very carcinogenic but I think the vinyl-group shall be destroyed in such
oxidizing environment. Maybe ethylchloride?
Hm, I found the parathion at the pesticide-collection of my parents and decided such a substance fits perfect in MY collection of chemicals! I don´t
really know how THEY got it. I think it´s some kind of restricted but they got it from someone they knew and who told him for their problem (some
nasty insects in the garden) it´s the best solution if not even the only.
If you´re intrested I might give you a list of pesticides, substances, etc. which contain parathion. I could not promise it but I think I´ve seen
some stuff like that somewhere.
guaguanco - 9-12-2003 at 15:21
At the risk of being a tedious bore, I want to remind people to be really careful with this kind of compound.
My uncle used some Parathion back in the early '70s on his yard. He apparently got some exposure. He developed cronic convulsions that (at the
time) were treated with barbiturates. He was pretty much incapacitated after that and after a few years took his own life.
Just a reminder that these things are no joke and deserve a lot of care and respect.
...now back to your regularly scheduled fun and games...
unionised - 11-12-2003 at 04:19
Equally tedious and boring warning. IIRC DDVP has been banned over here because it's a carcinogen.
(I wonder if anyone did the sums for people dying from DVPP vs people dying from insect carried diseases)
DDTea - 11-12-2003 at 07:50
In any case, I don't think DDVP would be a good molecule for decomposition/additional reactions to produce a more "active" compound.
Organophosphates, as a general rule, will decompose to a Trialkyl Phosphate, or otherwise some other useless compound. This is what DDVP does-- and
none of the intermediate compounds are notable.
However, Malathion and Glyphosphate have some interesting possibilities. This is because instead of the usual P-O-C bonds, they have a P-S-C and P-C
bonds, respectively. Glyphosphate is, in fact, a Phosphonate molecule, and thus it may be of particular interest... Also, it has two
acidic H's, which could possibly be reacted with an alcohol to form the corresponding dialkyl ester. As for the P-C bond... on hydrolysing, or
through natural decomposition by bacteria, it is oxidized to a useless P-O-C . However, would it be possible to attack the P-C group, and instead
replace it with C with a better leaving group (actually, the C is not the leaving group-- but could one be placed there?) ?