| Pages:
1
..
15
16
17
18
19
..
23 |
Microtek
National Hazard
Posts: 827
Registered: 23-9-2002
Member Is Offline
Mood: No Mood
|
|
@katyushaslab
I did see that entry in Ullmann, but everywhere else I have looked, people are diethyl- or dimethyl-carbonate instead of urea. In the end, I have
decided to buy some dimethyl carbonate to see if I can synthesize some carbohydrazide, and then urazine.
@Fulmen
If you have NaClO4 and a glass frit funnel it is also very easy. You just add dried NaClO4 to 37% HCl. The NaCl produced is almost insoluble in the
acid and precipitates out. Then you run it through the glass frit (or you could decant if you don't mind losing some) and distil the HCl off. I found
this process in a paper, and the authors had found that it gives a highly pure product with good efficiency. I have made 50% HClO4 this way, and found
it to be completely free of chloride. As a bonus, any chlorate in your perchlorate is destroyed.
|
|
|
katyushaslab
Hazard to Self
Posts: 81
Registered: 19-1-2021
Member Is Offline
Mood: precipitating
|
|
@Microtek: I found some mentions that semicarbazide will react further with hydrazine to form carbohydrazide. Semicarbazide can be prepared easily -
though you know that, as its your writeup from 2002 that I found on the matter from the E&W forum archive [0]. A relevant patent for semicarbazide
to carbohydrazide is DE2112398A1 [1].
From the patent, apparently refluxing 5.57g semicarbazide hydrochloride with 7.5g hydrazine hydrate were refluxed for 6 hours with a yield of 3.4g,
which is apparently around 75%.
[0]: https://www.thevespiary.org/rhodium/Rhodium/www.roguesci.org...
[1]: https://patents.google.com/patent/DE2112398A1/en
[Edited on 28-10-2021 by katyushaslab]
|
|
|
Microtek
National Hazard
Posts: 827
Registered: 23-9-2002
Member Is Offline
Mood: No Mood
|
|
Good find, that makes it much more OTC (I had forgotten all about that experiment). For those of us without access to modern analytic methods, it's
always nice with a few different synthetic routes - if the products several such routes appear identical, there's a decent likelyhood that it is the
one you were aiming for.
|
|
|
MineMan
National Hazard
Posts: 998
Registered: 29-3-2015
Member Is Offline
Mood: No Mood
|
|
Carbohydrazide is cheap and very available. Many members have it due to the DAUN experiment. More than they would want. I suggest that several would
probably be willing to ship.
The issue I have with the Urazine perchlorate is the sensitivity. It’s that of a primary explosive. With a sensitivity of 2J and 28N, I wouldn’t
want to plasticize it either. This may indeed be a primary explosive, based on sensitivity I would say it will DDT in a closed tube. It’s very
disappointing, that the sensitivity is so high, to me, this rules out and experiment using more than 5 grams. This would be the perfect EM for shaped
explosives, I hate to be cyclical, but as is often the case, HDEM disappoint.
|
|
|
Microtek
National Hazard
Posts: 827
Registered: 23-9-2002
Member Is Offline
Mood: No Mood
|
|
PETN has an impact sensitivity of 3.6J, mannitol hexanitrate 0.8-1.8 J. I couldn't find data for ETN, but I would guess around 2J. Definitely too
sensitive for the military, but I wouldn't worry too much in a laboratory setting.
|
|
|
katyushaslab
Hazard to Self
Posts: 81
Registered: 19-1-2021
Member Is Offline
Mood: precipitating
|
|
PETN is regarded as the "boundary" between primary and secondary in the modern literature. Interestingly, impact values do seem to vary lab to lab.
https://pubs.acs.org/doi/10.1021/acsomega.1c01115
|
|
|
Belowzero
Hazard to Others
Posts: 173
Registered: 6-5-2020
Location: Member Is Offline
Member Is Offline
|
|
I think this is mostly from a military perspective, it is understandable that its kinda problematic to drop a 500lb device on the deck of a ship and
having it explode.
They certainly have a point but to be honest I have handled this material quite often and it is remarkably difficult to get it to do anything, even
lighting a stove with it is a pain in the ass.
This does not mean that it does not deserve the utter most respect knowing the damage even a small amount can do.
However, the level of care that I practise is anything but common in the real world, that and the quantity.
MHN requires a heavy heavy hammer blow too, iirc its only once I got it to detonate by impact.
[Edited on 29-10-2021 by Belowzero]
[Edited on 30-10-2021 by Belowzero]
|
|
|
MineMan
National Hazard
Posts: 998
Registered: 29-3-2015
Member Is Offline
Mood: No Mood
|
|
Hmm. I have noticed with hammers, holding it at a slight angle or a rough surface makes all the difference. But that’s besides the point. Is there
any way to make this without perchlorate acid… rather a replacement with ammonium perchlorate. They didn’t give data on if it’s melt cast. None
the less, what’s the highest amount you can add a powdered explosive to a melt cast one? I hear 80 percent with no air bubbles.
Yes, PETN is more friction resistant. But. This is one synth. Controlling the crystal size or even coating should help. Much work to be done.
|
|
|
MineMan
National Hazard
Posts: 998
Registered: 29-3-2015
Member Is Offline
Mood: No Mood
|
|
It didn’t mention the exact synth. But did say crystals were .5-1mm. If they are reduced, sensitivity should improve.
Any way to do a replacement with ammonium perchlorate or another, instead of the acid.
|
|
|
MineMan
National Hazard
Posts: 998
Registered: 29-3-2015
Member Is Offline
Mood: No Mood
|
|
Quote: Originally posted by Microtek  | | PETN has an impact sensitivity of 3.6J, mannitol hexanitrate 0.8-1.8 J. I couldn't find data for ETN, but I would guess around 2J. Definitely too
sensitive for the military, but I wouldn't worry too much in a laboratory setting. |
I looked up my favorite primary. It has a impact value of 4J and friction of 20. About a tie with this compound. The issue, being a secondary, charges
of interest would need to be 50 grams. Do you think it’s safe to make that much in one pot with no worries? All hypothetical. The wise thing would
be to coat the material with 1-5 percent wax. PETN is safely used in det cord. But it’s friction value is 120N, not the 28.
Any update on if it can be pronated using displacement of another perchlorate.
|
|
|
Microtek
National Hazard
Posts: 827
Registered: 23-9-2002
Member Is Offline
Mood: No Mood
|
|
Well, my charges are rarely more than 1 gram secondary (hence my moniker), so a potential accident would be less catastrophic. Having said that, one
of the things I enjoy about this hobby, is the engineering aspect of it. It will be interesting to see how the sensitivity can be modified by adding
polymers or other binders, and how that will affect performance. I will post in this thread when I have something to report.
|
|
|
MineMan
National Hazard
Posts: 998
Registered: 29-3-2015
Member Is Offline
Mood: No Mood
|
|
| Quote: Originally posted by Microtek | | Well, my charges are rarely more than 1 gram secondary (hence my moniker), so a potential accident would be less catastrophic. Having said that, one
of the things I enjoy about this hobby, is the engineering aspect of it. It will be interesting to see how the sensitivity can be modified by adding
polymers or other binders, and how that will affect performance. I will post in this thread when I have something to report. |
I look forward to it. Can the perchlorate be made by meta thesis by another perchlorate such as ammonium perchlorate?? Please let me know.
You plan on making this compound? I am almost certain the sensitivity can be lessened.
|
|
|
Microtek
National Hazard
Posts: 827
Registered: 23-9-2002
Member Is Offline
Mood: No Mood
|
|
Ok, so I've synthesized what I believe to be urazine.
I began from dimethylcarbonate and followed "Green Synthetic Method for1,5-Disubstituted Carbohydrazones" by Li et al.
Thus dimethylcarbonate (9g, 0.1 mol) was mixed with hydrazine hydrate (5.5 g, 0.11 mol) in a small two-necked flask fitted with reflux coloumn and
thermometer adapter and heated with stirring to 70C. The mix was held at this temp (with constant stirring) for 4 hrs.
Then the reflux coloumn was replaced with a distillation head, and a small amount of liquid was distilled off under reduced pressure. I think most of
the liberated methanol had probably escaped through the reflux coloumn, or else weren't condensed in the cooler in this step.
After cooling down, more hydrazine hydrate (11 g, 0.22 mol) was added, and the mix was stirred at 70C for another 4 hrs (with reflux coloumn).
Then the distillation head was attached again, and the mix was concentrated under reduced pressure until a white precipitate began to form.
Heating was stopped, and once cooled, the reaction mixture was filtered to recover the crude product, which should be carbohydrazide. The product
consisted of large, stocky crystals and after washing with a little water and drying overnight, it weighed 6,77 g, corresponding to ca. 75% yield.
To synthesize urazine, the method from "Inorganic Synthesis" (vol 4, p 30-31) was followed. I had the problem that the small amounts of material (6.77
g carbohydrazide and 7 ml HCl, 12M) didn't allow me to effectively monitor the temperature. I used an IR thermometer, but couldn't get very consistent
readings. The procedure calls for slowly raising the temp. There should be a plateau around 215C which it should hold for about an hour. Then, when
the temp increases to above 220C, heating is stopped and the reaction is allowed to cool.
Then water (8 ml) is added, and the reaction is heated to dissolve byproduct hydrazine*HCl. The product, urazine, is not very soluble in water (0.32 g
in 100 ml at 0C) so isolation is easy.
After washing and drying, 1.878 g crude product was obtained. I recrystallized it from 0.1M HCl as outlined in the litterature, but I'm not sure it
was necessary; the melting point didn't seem to change much. Anyway, after recrystallization, I was left with 1.548 g urazine (assuming that is what
it is - solubilities and melting point corroborate the assumption, but I haven't tried any other methods of analysis).
The total yield is just 26.6 % based on dimethylcarbonate, and less based on hydrazine hydrate. This is still enough for doing some testing since it
should give about 2.6 g urazine perchlorate given the yield from the Klapötke paper. However, I don't like this procedure since it is uses quite a
lot of hydrazine. I find this problematic, both because of the expense and the potential health effects (I do work in a fume hood, but accidents do
happen).
|
|
|
MineMan
National Hazard
Posts: 998
Registered: 29-3-2015
Member Is Offline
Mood: No Mood
|
|
| Quote: Originally posted by Microtek | Ok, so I've synthesized what I believe to be urazine.
I began from dimethylcarbonate and followed "Green Synthetic Method for1,5-Disubstituted Carbohydrazones" by Li et al.
Thus dimethylcarbonate (9g, 0.1 mol) was mixed with hydrazine hydrate (5.5 g, 0.11 mol) in a small two-necked flask fitted with reflux coloumn and
thermometer adapter and heated with stirring to 70C. The mix was held at this temp (with constant stirring) for 4 hrs.
Then the reflux coloumn was replaced with a distillation head, and a small amount of liquid was distilled off under reduced pressure. I think most of
the liberated methanol had probably escaped through the reflux coloumn, or else weren't condensed in the cooler in this step.
After cooling down, more hydrazine hydrate (11 g, 0.22 mol) was added, and the mix was stirred at 70C for another 4 hrs (with reflux coloumn).
Then the distillation head was attached again, and the mix was concentrated under reduced pressure until a white precipitate began to form.
Heating was stopped, and once cooled, the reaction mixture was filtered to recover the crude product, which should be carbohydrazide. The product
consisted of large, stocky crystals and after washing with a little water and drying overnight, it weighed 6,77 g, corresponding to ca. 75% yield.
To synthesize urazine, the method from "Inorganic Synthesis" (vol 4, p 30-31) was followed. I had the problem that the small amounts of material (6.77
g carbohydrazide and 7 ml HCl, 12M) didn't allow me to effectively monitor the temperature. I used an IR thermometer, but couldn't get very consistent
readings. The procedure calls for slowly raising the temp. There should be a plateau around 215C which it should hold for about an hour. Then, when
the temp increases to above 220C, heating is stopped and the reaction is allowed to cool.
Then water (8 ml) is added, and the reaction is heated to dissolve byproduct hydrazine*HCl. The product, urazine, is not very soluble in water (0.32 g
in 100 ml at 0C) so isolation is easy.
After washing and drying, 1.878 g crude product was obtained. I recrystallized it from 0.1M HCl as outlined in the litterature, but I'm not sure it
was necessary; the melting point didn't seem to change much. Anyway, after recrystallization, I was left with 1.548 g urazine (assuming that is what
it is - solubilities and melting point corroborate the assumption, but I haven't tried any other methods of analysis).
The total yield is just 26.6 % based on dimethylcarbonate, and less based on hydrazine hydrate. This is still enough for doing some testing since it
should give about 2.6 g urazine perchlorate given the yield from the Klapötke paper. However, I don't like this procedure since it is uses quite a
lot of hydrazine. I find this problematic, both because of the expense and the potential health effects (I do work in a fume hood, but accidents do
happen).
|
Why not just buy carbohydrazide, or if in the US I can send you 50 grams. If it is Urazine it should be a VERY dense organic molecule at 2.4g/cc.
That could be a way to find out.
|
|
|
Microtek
National Hazard
Posts: 827
Registered: 23-9-2002
Member Is Offline
Mood: No Mood
|
|
I'm in the EU, and haven't been able to find carbohydrazide locally. Importing from outside the EU is quite expensive due to customs and
administrative fees. At any rate, this is a chemistry forum, and I enjoy the lab work.
If one were to require more than a few grams, buying carbohydrazide would certainly be the way to go. Also, in the condensation reaction where two
molecules of carbohydrazide form one of urazine, two molecules of hydrazine are expelled (as the HCl salt). Some of this is probably decomposed at the
reaction temperature but according to the writeup in "Inorganic Synthesis", most of the byproduct is hydrazine*HCl. Since urazine is easily separated,
I was thinking that maybe the hydrazine could be recovered by precipitating as the bisulfate. If all the biproduct hydrazine could be recovered this
way, you would get 2.24 gram of hydrazine sulfate for each gram of urazine produced, perhaps making this a viable route to HS.
|
|
|
katyushaslab
Hazard to Self
Posts: 81
Registered: 19-1-2021
Member Is Offline
Mood: precipitating
|
|
Being able to recover some hydrazine (as sulphate) and feed it forward into other reactions is a very interesting possibility, especially for waste
management.
|
|
|
MineMan
National Hazard
Posts: 998
Registered: 29-3-2015
Member Is Offline
Mood: No Mood
|
|
How would you break the hydrazine chloride into hydrazine sulfate?! Could this be done via a one pot reaction?
How can Urazine really be 2.4g/cc. I know of no other organic molecule with such a density.
|
|
|
Microtek
National Hazard
Posts: 827
Registered: 23-9-2002
Member Is Offline
Mood: No Mood
|
|
That is a predicted value using the ACDlabs software. ACDlabs is notorious for overestimating the density of organic molecules, so I am quite certain
the actual density is somewhat lower. In fact, I would be extremely surprised if urazine isn't less dense than the perchlorate salt.
Hydrazine*HCl to sulfate is a simple metathesis reaction, and is driven by the precipitation of low solubility hydrazine bisulfate. I would simply add
50% sulfuric acid (possibly even sodium sulfate) directly to the filtrate after filtering off the urazine, then filtering off the formed HS.
|
|
|
MineMan
National Hazard
Posts: 998
Registered: 29-3-2015
Member Is Offline
Mood: No Mood
|
|
| Quote: Originally posted by Microtek | That is a predicted value using the ACDlabs software. ACDlabs is notorious for overestimating the density of organic molecules, so I am quite certain
the actual density is somewhat lower. In fact, I would be extremely surprised if urazine isn't less dense than the perchlorate salt.
Hydrazine*HCl to sulfate is a simple metathesis reaction, and is driven by the precipitation of low solubility hydrazine bisulfate. I would simply add
50% sulfuric acid (possibly even sodium sulfate) directly to the filtrate after filtering off the urazine, then filtering off the formed HS.
|
I was wondering how the perchlorate salt was less dense! Could you do a density test for us?!
Seems to be a very beneficial reaction… big question is can you make the perchlorate salt via meta thesis?
|
|
|
Microtek
National Hazard
Posts: 827
Registered: 23-9-2002
Member Is Offline
Mood: No Mood
|
|
I'm fairly certain that metathesis won't work to produce urazine perchlorate. The urazine is a very weak base, and even with HClO4 the salt is only
formed on heating.
|
|
|
MineMan
National Hazard
Posts: 998
Registered: 29-3-2015
Member Is Offline
Mood: No Mood
|
|
| Quote: Originally posted by Microtek | | I'm fairly certain that metathesis won't work to produce urazine perchlorate. The urazine is a very weak base, and even with HClO4 the salt is only
formed on heating. |
Why is it possible with aminoguanidine?
What percentage of perchloric is needed… wouldn’t a nitrate salt be almost as high performing?
|
|
|
Microtek
National Hazard
Posts: 827
Registered: 23-9-2002
Member Is Offline
Mood: No Mood
|
|
My experiments with urazine are on hold, since I have come to doubt the identity (or maybe purity) of the compound I had synthesized. It seems I will
have to buy some after all.
In the mean time, I have been experimenting with some 4-amino-1,2,4-triazole that I ordered some years ago to test the capability of a supplier. I was
searching for candidates for melt castable explosives, and wanted to try some aminotriazole compounds. I had some limited success with the picrate
salt IIRC, but in the end I put it on indefinite hold.
However, the urazine salts inspired me to make some more tests. The nitrate and perchlorate salts are both energetic as would be expected, but the
nitrate is not reliably initiated in my setup. It may possibly be of interest as a less sensitive explosive.
The perchlorate salt is much more sensitive, and seems to propagate detonation very effectively. My initial sensitivity tests involve a rapid cook-off
test, a hammer test and a friction test. In the cook-off test, 50 mg ATrzP melts, bubbles and finally "pops" with enough force to make a large hole in
the Al foil it is held on. It doesn't detonate though. ATrzN just burns with a hissing flame. In the hammer test 50 mg ATrzP is easily set off with
moderate hammer blows, and detonates with a loud report and a VERY bright flash. The explosion is reminiscent of a drop of NG on tissue paper, in that
it seems to be the entire mass of explosive that detonates (often, these tests will only set off parts of the explosive, and successive blows can
achieve more detonations). ATrzN is only set off with difficulty in the hammer test. I wasn't able to initiate either of them by rubbing between
hammer and anvil, but AtrzP gave a (very) positive reaction in my oblique impact test, which is a steel pendulum drop hammer which impacts a steel
surface at a 25 degree angle from horizontal. The pendulum can be released from varying heights and the sample can be placed directly on the steel
anvil or on a small piece of fine grit sand paper. In this test, ATrzP gave a positive test (any sign of chemical decomposition) at a slightly lower
height than PETN, but did so more reliably. PETN often does not explode, but decomposition can be detected by smell. ATrzP usually explodes with flame
and a clearly audible report.
I also tested performance in the manner that I described under the "NHN without hydrazine hydrate" thread. I didn't press it very much because of the
insufficiently tested sensitivity, but at a density of only 1.55 g/cc, the dent in aluminum bar stock was on par with that of HMX at >1.8 g/cc. If
I can tame the sensitivity of the material (inert binders, perchlorate/nitrate mixes or other methods) it could be an interesting avenue of research.
I experimented with two different methods of preparation: One was straight forward reaction of 4-amino-1,2,4-triazole with HClO4 followed by
evaporation of the water.
The other was reaction of the triazole with hydrochloric acid followed by evaporation. Then the hydrochloride was dissolved in ethanol, and a
saturated solution of NaClO4 in ethanol was added at 55 C. NaCl precipitated and the mix was stirred at 55C for 10 minutes. The NaCl was filtered off,
and the ethanol was evaporated.
The products from the two reactions are not identical. They are both very explosive and react about the same in the hammer and cook-off tests, but the
ethanol preparation produces a material that is difficult to dry out, while the HClO4 method makes a non-hygroscopic material (but mine was
contaminated with an excess of one of the reactants).
There is much work to be done.
[Edited on 22-12-2021 by Microtek]
|
|
|
MineMan
National Hazard
Posts: 998
Registered: 29-3-2015
Member Is Offline
Mood: No Mood
|
|
| Quote: Originally posted by Microtek | My experiments with urazine are on hold, since I have come to doubt the identity (or maybe purity) of the compound I had synthesized. It seems I will
have to buy some after all.
In the mean time, I have been experimenting with some 4-amino-1,2,4-triazole that I ordered some years ago to test the capability of a supplier. I was
searching for candidates for melt castable explosives, and wanted to try some aminotriazole compounds. I had some limited success with the picrate
salt IIRC, but in the end I put it on indefinite hold.
However, the urazine salts inspired me to make some more tests. The nitrate and perchlorate salts are both energetic as would be expected, but the
nitrate is not reliably initiated in my setup. It may possibly be of interest as a less sensitive explosive.
The perchlorate salt is much more sensitive, and seems to propagate detonation very effectively. My initial sensitivity tests involve a rapid cook-off
test, a hammer test and a friction test. In the cook-off test, 50 mg ATrzP melts, bubbles and finally "pops" with enough force to make a large hole in
the Al foil it is held on. It doesn't detonate though. ATrzN just burns with a hissing flame. In the hammer test 50 mg ATrzP is easily set off with
moderate hammer blows, and detonates with a loud report and a VERY bright flash. The explosion is reminiscent of a drop of NG on tissue paper, in that
it seems to be the entire mass of explosive that detonates (often, these tests will only set off parts of the explosive, and successive blows can
achieve more detonations). ATrzN is only set off with difficulty in the hammer test. I wasn't able to initiate either of them by rubbing between
hammer and anvil, but AtrzP gave a (very) positive reaction in my oblique impact test, which is a steel pendulum drop hammer which impacts a steel
surface at a 25 degree angle from horizontal. The pendulum can be released from varying heights and the sample can be placed directly on the steel
anvil or on a small piece of fine grit sand paper. In this test, ATrzP gave a positive test (any sign of chemical decomposition) at a slightly lower
height than PETN, but did so more reliably. PETN often does not explode, but decomposition can be detected by smell. ATrzP usually explodes with flame
and a clearly audible report.
I also tested performance in the manner that I described under the "NHN without hydrazine hydrate" thread. I didn't press it very much because of the
insufficiently tested sensitivity, but at a density of only 1.55 g/cc, the dent in aluminum bar stock was on par with that of HMX at >1.8 g/cc. If
I can tame the sensitivity of the material (inert binders, perchlorate/nitrate mixes or other methods) it could be an interesting avenue of research.
I experimented with two different methods of preparation: One was straight forward reaction of 4-amino-1,2,4-triazole with HClO4 followed by
evaporation of the water.
The other was reaction of the triazole with hydrochloric acid followed by evaporation. Then the hydrochloride was dissolved in ethanol, and a
saturated solution of NaClO4 in ethanol was added at 55 C. NaCl precipitated and the mix was stirred at 55C for 10 minutes. The NaCl was filtered off,
and the ethanol was evaporated.
The products from the two reactions are not identical. They are both very explosive and react about the same in the hammer and cook-off tests, but the
ethanol preparation produces a material that is difficult to dry out, while the HClO4 method makes a non-hygroscopic material (but mine was
contaminated with an excess of one of the reactants).
There is much work to be done.
[Edited on 22-12-2021 by Microtek] |
Is a dinitrate possible? Urazine has the benefit of oxygen balance.
|
|
|
Laboratory of Liptakov
International Hazard
Posts: 1335
Registered: 2-9-2014
Location: Technion Haifa
Member Is Offline
Mood: cool.gif
|
|
I keep saying that. Perchlorates are an unexplored area. Many discoveries are yet to be made. In the sense of primary and primarily secondary
choristans. For easy safely initiation.
Development of primarily - secondary substances CHP (2015) Lithex (2022) Brightelite (2023) Nitrocelite (2024)
|
|
|
Microtek
National Hazard
Posts: 827
Registered: 23-9-2002
Member Is Offline
Mood: No Mood
|
|
In my research into triazoles, I recently stumbled onto a class of coordination complexes known as EMOFs - energetic metal-organic frameworks.
In a number of very new papers, the authors are throwing around some quite extraordinary numbers:
Substances having measured sensitivities less than TNT coupled with calculated detonation energy of 3.9 kcal/g (that is not an error; about twice ONC
or CL-20), Pcj of 50-60 GPa and VOD of 10-11 km/s. In addition, they have measured thermal stabilities of around 300C.
Of course, several of these numbers are calculated and it remains to be seen whether the models are any good at predicting performance at these
extremes of the spectrum. Still, if they are reasonably close, it is a huge leap in performance, without any compromise with regards to safety.
Some of the most energetic EMOFs I have seen are based on coupled furazan-tetrazoles as ligands around metal ions. These form 1-,2- , or 3-D
frameworks that can have other ions in the voids in the structure.
Some appetizers:
https://pubs.acs.org/doi/10.1021/acs.inorgchem.9b01636#
Almost 12 km/s
Very high densities
[Edited on 10-1-2022 by Microtek]
[Edited on 10-1-2022 by Microtek]
|
|
|
| Pages:
1
..
15
16
17
18
19
..
23 |
![[*]](images/xpblue/default_icon.gif){kind=icon}
