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Tsjerk
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Bromo-DDT, p,p-dibromo-diphenyl-1,1,1-trichloro-ethane
I have a nice assortment of plants in my house, off which many in an indoor "greenhouse". I had a spare space, enclosed between two walls, with a big
window on the south in my apartment. I build a frame of wood with aluminium corner strips all around where I could glue in Plexiglas.
Before building this greenhouse I already had problems, mainly with aphid. I tried everything against the buggers... spiritus with green soap,
pyrethrum, pyrethrum with some aphid stress pheromone that should make them come out of there hiding place, lady bug larvae... nothing got rid of them
completely. I have them under control now, but I fear coming summer.
My plants outside where fine after one spray with the spiritus/soap, but that was probably because within minutes there were dozens of wasps around to
pick up the peaces. Indoor? Not to much. I even cut of my chili plants, because they were infested and on the brink of dying. They are starting to
grow right now but the aphid are popping up again... in February winter.. little buggers.
So, then, lets take drastic measures: DDT. or actually the bromo analogue. I would have preferred the fluorine analogue, but I thought that was a bit
expensive, and I could get a nice batch of bromobenzene, which could later be used for other experiments a bit easier than chlorobenzene. The bromo is
about 20 times less toxic to insect compared to the chloro, but chloro-DDT is so extremely toxic, that shouldn't be a problem.
It is quite easy:
Chloral hydrate (25 g, 0.151 mol) was dissolved in sulfuric acid (96%, 125 ml) and bromobenzene (50 g, 0.318 mol, 1.05 eq.) was added. This mixture
was stirred with a magnetic stirrer for 24 hours.
The reaction mixture was poured in 500 ml of crushed ice in water. The white water emulsion on top was discarded and the yellow bottom organic layer
was seperated in a seperation funnel and stirred with a brine solution. The organic layer lost the yellow color and turned into a suspension of white
crystals in a colorless oil.
The suspension was filtered through coarse anhydrous magnesium sulfate. the filtrate was a clear oil which formed white crystals on the top upon
standing. The magnesium sulfate was washed with little DCM and the filtrate was pooled with the oily filtrate from before. The DCM is now being
evaporated of under a draft of air on a magnetic stirrer.
A little of white crystals were scraped from the side of the container and was suspended in boiling water. An unknown substance separates as a liquid
and floats on the water. The water was poured of and a white solid with a melting point above 100oC stayed behind.
About 50 mg of this compound was put on a hotplate on low heat in my indoor greenhouse. The substance started to sublime. The little flies all around
seem to panic and try to get away. After half an hour the flies seem to be uncoordinated and are for the first time even flying outside of the
greenhouse.
Once I have determined the total yield after evaporating the DCM and bromobenzene off and after a quick boiling water wash I will check how the little
buggers are doing and if necessary I will sublime a bit more of the compound.
source
Not many (big) plants yet, but I guess in July they will be competing for light.
[Edited on 6-2-2020 by Tsjerk]
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Herr Haber
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Wonderful !
Having Chloral hydrate and 100ml of Bromobenzene I was thinking about making this same DDT analogue.
You just saved me a bit of research for the workup 
The spirit of adventure was upon me. Having nitric acid and copper, I had only to learn what the words 'act upon' meant. - Ira Remsen
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Tsjerk
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Kein Problem!
One thing is for sure, this is one nice insecticide! Three hours in and no flies are flying anymore, only with the small sample run. Even better, the
aphid are falling dead from the leaves by only giving the plant a little shake. Good stuff.
[Edited on 6-2-2020 by Tsjerk]
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woelen
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Aren't you afraid of potential health issues by exposing yourself to this stuff? It sounds like being quite toxic and you use this inside your
apartment.
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Tsjerk
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DDT is not that toxic, not to animals other than insects at least. It gets toxic when it accumulates in fatty tissues, that was the problem in the
50's and the 60's and reason to ban DDT. The USA were producing 100.000.000 tonnes at some point... per month. And Europe was not far behind.
After some decades of usage at this scale, animals higher up in the food chain started to develop symptoms, like infertility and thin egg shells.
Every time a mammal would breast feed offspring, the accumulated DDT would be transmitted, giving the offspring a worse head start in life than they
had themselves. Birds would accumulate the DDT in egg yolk an pass it on that way.
Humans never got into trouble because from the beginning it was not aloud to spray the stuff a week or so before harvest. Also weeds used to feed life
stock were not sprayed some time before harvest. DDT dissolves quite poorly and therefore is not taken up into plants, the dust does the job. When you
sublime it, and are not present until the DDT settles on surfaces, and don't lick the walls afterwards, you won't get much into your system. The crops
would get rid of the DDT either by rain or by washing the vegetables with some water before eating.
I'm not too worried about the probably ten grams I will need in a lifetime to eradicate every insect in my small greenhouses. Also the bromo-DDT is
more bio-degradable compared to chloro-DDT. Fluoro-DDT is even more degradable, but on the milligram scale I'm using it... well, who cares.
When my grandpa learned about the upcoming ban on DDT he bought a 25 kg bag, that lasted about ten years, and he was running an indoor cattle farm
with over a thousand calf. I never experienced the DDT time, but the days without were terrible, the shit-flies were everywhere, all day and all year.
Apparently he could keep a whole industrial farm fly free with 2,5 kg a year.
I do remember a time at my uncles place... he had a special stash, just for inside use. When the flies would get to bad, he put a table spoon in a old
can on the stove. We had to leave the house for an hour or so. After that... no flies for 6 months. Every fly landing on the wall would drop dead.
Edit: I don't even know the mechanism of action... I will have a look.
[Edited on 6-2-2020 by Tsjerk]
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woelen
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Interesting to see that a compound can have such a strong effect on insects, while being relatively non-toxic for higher life forms. I did not know
that, I never dived deeper into the chemistry and selective toxicity of DDT. I indeed think that a few mg does not pose a serious risk for you. You
also only get a tiny fraction of that in your system. a few tens of mg of release into the air is not equivalent to your body taking up that amount.
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Fery
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Tsjerk - wow, beautiful. I do not have any greenhouse, just garden. I attract ladybugs, they are very quick on eating the aphid. I observed that ants
are spreading aphid larvae in my garden - aphid sucks plants so plants weep blood and ants sucks the blood then. When I see row of ants walking to any
plant in my garden, they carry aphid and spread it to the plant, take care of the aphid and suck the blood of the plant.
Anyway nice synthesis !
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DavidJR
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Quote: Originally posted by woelen  | | Interesting to see that a compound can have such a strong effect on insects, while being relatively non-toxic for higher life forms. I did not know
that, I never dived deeper into the chemistry and selective toxicity of DDT. |
That's nothing compared to modern neonicotinoid pesticides. Take for example imidacloprid. In mammals, it's not particularly toxic, with an oral LD50
of about 450mg/kg. To insects, on the other hand, it is incredibly toxic. This sounds like exactly what you want from an insecticide - but the
unfortunate downside is that it (and other neonicotinoids) have had an extremely negative impact on non-target insects, most notably bees.
In that vial there is approximately 3.4g of pure imidacloprid. Imidacloprid is one of the most toxic-to-bees compounds known, with an LD50 of between
5 and 70ng per bee (some colonies are apparently more sensitive than others). Conservatively, I have enough in that vial to kill at least 24 million
bees, and quite possibly enough to kill a few hundred million bees.
Neonicotinoids have also been strongly linked to colony collapse disorder in honeybees. Even at sublethal levels below the limit of detection,
honeybees are adversely affected by them. They exhibit behavioural changes which lowers their rate of survival, and also, they become more susceptible
to infestation by a parasite called Varroa mites.
In 2017, China alone exported 31,595 tonnes of imidacloprid. It's a wonder we have any bees left at all.
[Edited on 6-2-2020 by DavidJR]
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Tsjerk
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| Quote: Originally posted by Fery | Tsjerk - wow, beautiful. I do not have any greenhouse, just garden. I attract ladybugs, they are very quick on eating the aphid. I observed that ants
are spreading aphid larvae in my garden - aphid sucks plants so plants weep blood and ants sucks the blood then. When I see row of ants walking to any
plant in my garden, they carry aphid and spread it to the plant, take care of the aphid and suck the blood of the plant.
Anyway nice synthesis ! |
Yes, ants and aphids have a lovely symbiosis, the ants protect the aphids as the aphids shit their (in Dutch) "honingdauw" all over your car. I
understand the ants though, the aphid shit is pure sucrose.
Neonicotinoids are nice because they are biodegradable. I just had a quick look, apparently imidacloprid has a half life of 39 days, while DDT has a
half life of 15 years. Also imidacloprid has been banned in the EU in 2013.
Without pesticides we would not have been here, with 7 billion people.
One the other hand , if DDT would have been banned 10 years later, or more accurately, if the ban would not have been forced on Africa, malaria would
not exist today.
European countries used DDT to exterminate insects (and malaria) transmitting deadly deceases, and then found out orca's and ice-bears and some birds
suffered, withholding Africans from using DDT, preventing them from eradicating malaria.
[Edited on 6-2-2020 by Tsjerk]
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morganbw
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Nice post.
I considered a DDT synth a very long time ago. I have yet to do so but I do still have an interest.
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DavidJR
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| Quote: Originally posted by Tsjerk |
Neonicotinoids are nice because they are biodegradable. I just had a quick look, apparently imidacloprid has a half life of 39 days, while DDT has a
half life of 15 years. Also imidacloprid has been banned in the EU in 2013.
Without pesticides we would not have been here, with 7 billion people.
One the other hand , if DDT would have been banned 10 years later, or more accurately, if the ban would not have been forced on Africa, malaria would
not exist today.
European countries used DDT to exterminate insects (and malaria) transmitting deadly deceases, and then found out orca's and ice-bears and some birds
suffered, withholding Africans from using DDT, preventing them from eradicating malaria.
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Of course - it is not quite so simple as just saying insecticide x is bad. Insecticides are certainly very important (but so are bees).
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Tsjerk
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If I would run this synthesis again I wouldn't use an excess of bromobenzene again... I had the gut feeling it would evaporate quite easily, but it
seems to be quite persistent. I still didn't get it to fully crystallize and I suspect the bromobenzene to be guilty for that. I could pull I vacuum
but that would mean more dirty glass and more mechanical losses.
What I have now is a slush of crystals. The DCM seems to be long gone, but there is some liquid junk.
Maybe I will just poor boiling water over it, it might separate.
Edit: still at least a 90% reduction of flies, only after the 50 mg test. As far as I can tell all aphids are dead. Normally they don't care too much
when you touch them and the will stay where they are, now they just drop from the leaves with the slightest touch. I will know for sure whether they
are dead or not in a few days, they turn brown after a couple of days when dead.
Edit 2: And I would use double the amount of sulfuric acid. The volume of product I have after evaporating for more than a day is almost halve the
volume of the oily liquid I had after first poring the reaction on ice. I guess there was to much water in the reaction, most preparations are done
with a bit of oleum and anhydrous chloral, although it should be doable with just 96% sulfuric acid and the hydrate of chloral.
[Edited on 7-2-2020 by Tsjerk]
[Edited on 7-2-2020 by Tsjerk]
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Herr Haber
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Keep sharing your thoughts Tsjerk
I have about 50 cardboard boxes in my living room after a major overhaul of the appartment but as soon as I'm done with that I'll proceed with that
synthesis.
I wont need much either. I was planning on dissolving the bromo-DDT in a solvent so it could be painted on wood to ward off against hornets.
Dont really need them dead, just *away*.
The spirit of adventure was upon me. Having nitric acid and copper, I had only to learn what the words 'act upon' meant. - Ira Remsen
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mayko
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First of all, nice chemistry; the di-bromo analog is an interesting twist. How did you manage waste disposal?
I’m not qualified to comment on the toxicology of DDT in any depth but things like the Pine River Statement (https://www.ncbi.nlm.nih.gov/pubmed/19750098) would make me …. reluctant to use it without very good cause.
Despite its reputation, DDT is not a magic bullet against malaria, for a number of reasons. A big one is insect resistance. Sri Lanka learned this the
hard way in the early 1970’s, when their eradication program hit a brick wall: the insecticide they'd relied on just wasn’t working any more. In
spite of intense spraying, they suffered a serious malaria outbreak, forcing them to switch IIRC to the more expensive malathion. Their eradication
program continued without DDT, declaring success a few years ago.
The EPA has no jurisdiction outside of the US, so I’m not sure how it could have forced its ruling on Africa. Even if it could, the 1972 ban had a
public health exemption (the later Stockholm Convention exempted DDT for the same reason). It also didn’t prohibit manufacture or export, which
continued by the ton. According the the latest World Malaria Report from the WHO, several African nations are using DDT to this day. But while it
remains a tool in the tool box, it has almost entirely been displaced by better alternatives. In particular, bed netting is more effective and less
expensive than outdoor DDT spraying.
It can also be a false opposition to pit wildlife against disease control. Insectivorous bats and birds are our strongest allies in fighting
mosquitoes, but are particularly hard-hit by DDT.
al-khemie is not a terrorist organization
"Chemicals, chemicals... I need chemicals!" - George Hayduke
"Wubbalubba dub-dub!" - Rick Sanchez
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Tsjerk
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There is a big difference between "a shown effect on fertility" and death.
When a species develops resistance, your toxin either isn't toxic enough or didn't use enough of it.
No, EPA (whatever it may be) does not have jurisdiction in any other country (?), but African countries usually don't have the facilities to produce
DDT on a ton scale. When the USA and the EU decide they won't produce DDT anymore, the African countries are screwed.
Yes there are many countries, mostly African, that still use DDT, good for them. But they use it on a ton scale. Not a giga ton scale.
Edit: sorry, not a mega but a giga ton scale.
Edit 2:
I disposed everything down the drain. Do you think anyone down there would have a problem with that?
[Edited on 7-2-2020 by Tsjerk]
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Johnny Windchimes
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Where is NileRed's DDT video when you need it huh?
I used to have a copy but my hard drive bit the dust....
Anyone have a link?
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Tsjerk
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I just found out how to get the compound as a clean crystalline product. The stuff is remarkably insoluble in hot methanol, probably even less in cold
methanol. I tried to recrystallize the DDT with methanol, but nothing seemed to dissolve, bromobenzene however is miscible with methanol. I was left
with a pure white powder after filtration. No melting point was measured, but it is far above 100 degrees. That is good enough for me, as I used
bromobenzene in excess and let the reaction go for about 24 hours.
Next time I will try to directly crash the DDT with methanol.
Need it for what?
[Edited on 8-2-2020 by Tsjerk]
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mayko
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| Quote: | | There is a big difference between "a shown effect on fertility" and death. |
Sure, the chronic effects of pesticide exposure must be weighed against the acute risk of infectious disease – I don’t know how anyone could
disagree with that. My point, though, is that there is a big difference between dying of malaria and having aphids on one’s houseplants.
| Quote: |
When a species develops resistance, your toxin either isn't toxic enough or didn't use enough of it. |
I don’t know where to even begin with this. It’s tautological in not one but two dimensions. We measure toxicity in terms of LD50, because the
LD100 just isn’t a useful figure. Even if it was, there is no reason to think that it would be practical or even feasible to administer an LD100 on
a national or global scale. Agricultural use on crop pests (which is what almost all “bans” targeted) are another, uh, fly in the ointment. (A
similar situation exists today with antibiotic resistance: it’s obviously important to follow a full course of antibiotic to prevent resistance, but
that’s only going to help so much when Farmer Bob next door is pumping his pigs full of the same stuff as a preventative measure. Upping the amount used also increases the selection pressure for resistance.
Finally, how resistance arose is not relevant: it’s here, it’s not going away, and it’s dramatically reduced the effectiveness of DDT.
| Quote: |
No, EPA (whatever it may be) does not have jurisdiction in any other country (?), but African countries usually don't have the facilities to produce
DDT on a ton scale. When the USA and the EU decide they won't produce DDT anymore, the African countries are screwed.
|
The US continued to manufacture and export DDT for at least another decade and a half. The US and Europe are also not the only places in the world
with chemical industries. China was a major producer until recently. India is the last big one and is in the process of phasing it out. The reason
isn’t a 1972 US EPA ruling. DDT played an (important but often overstated) role in the US eradication program, but most of a century has passed
since, and now it’s largely obsolete.
al-khemie is not a terrorist organization
"Chemicals, chemicals... I need chemicals!" - George Hayduke
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Tsjerk
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| Quote: Originally posted by mayko | Sure, the chronic effects of pesticide exposure must be weighed against the acute risk of infectious disease – I don’t know how anyone could
disagree with that. My point, though, is that there is a big difference between dying of malaria and having aphids on one’s houseplants.
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I used 50 milligram.
[Edited on 8-2-2020 by Tsjerk]
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XeonTheMGPony
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| Quote: Originally posted by woelen | | Interesting to see that a compound can have such a strong effect on insects, while being relatively non-toxic for higher life forms. I did not know
that, I never dived deeper into the chemistry and selective toxicity of DDT. I indeed think that a few mg does not pose a serious risk for you. You
also only get a tiny fraction of that in your system. a few tens of mg of release into the air is not equivalent to your body taking up that amount.
|
Most bug sprays are nerve gas for bugs, where most animals can metabolize the substances
Permethrin is extremely lethal to ticks and fleas, but harmless to humans and dogs, but interestingly, all so very toxic to cats!
https://en.wikipedia.org/wiki/Permethrin
Why some tick and flea treatments can not be used with cats.
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DavidJR
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I never found permethrin to work all that well on fleas. Also, it is found in flea collars etc intended for cats...
Frontline, active ingredient fipronil, used to work pretty well, but in some areas there are now fipronil resistant fleas. We had to switch to Bayer
Advantage, which is imidacloprid (dissolved in benzyl alcohol which leaves your cat smelling of almonds for a few days). This works very well indeed.
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XeonTheMGPony
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| Quote: Originally posted by DavidJR | I never found permethrin to work all that well on fleas. Also, it is found in flea collars etc intended for cats...
Frontline, active ingredient fipronil, used to work pretty well, but in some areas there are now fipronil resistant fleas. We had to switch to Bayer
Advantage, which is imidacloprid (dissolved in benzyl alcohol which leaves your cat smelling of almonds for a few days). This works very well indeed.
|
there is a natural form and synthetic, the synthetic is the most lethal to insects (And cats), I use it mainly for ticks and it is a non miracle for
that! ticks are horrible in my area, and I have gotten it down from hundreds a day on the dogs and me to a dozen a day during tick season, I spray the
house the bed, the dogs bed the clothing.
I looked up the synthetic route at some point but can't recall.
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Tsjerk
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I got a dry crystalline substance after a methanol wash. The yield sucks, I don't know what it is but I guess about 20 grams. That should be a
lifetime supply though. I just subblimed 100 mg in my greenhouse. Just to be sure.
I will report anything flying or crawling around in the next months.
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unionised
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There are natural pyrethroids but I doubt permethrin (with two chlorines in the structure) is natural.
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Herr Haber
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Indeed.
Permethrin WILL kill a cat.
Many cat owners killed their pet by using those droppers / syringes made for dogs.
Many insecticides in your average hardware store arsenal contain permethrin as I discovered a few years ago when I got scabies.
The spirit of adventure was upon me. Having nitric acid and copper, I had only to learn what the words 'act upon' meant. - Ira Remsen
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