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Author: Subject: Nitromethane, nitroethane, nitropropane synthesis via industrial route
Melgar
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[*] posted on 30-4-2010 at 16:59


Oh, well right, obviously. I had that in my first diagram. The whole thing would be about six feet long, and the collection flask would be completely on the other side of the apparatus. And it'd only be a liter or so in capacity. I was going to get one of those little portable tanks of propane, but now I'm planning for the barbecue grill 20-pound variety because they make regulators for them. Plus the reactor would have such a small volume that even an explosion wouldn't be enough to rupture the tubing. After all, a gas exploding doesn't have anywhere near the increase in volume as a solid or liquid exploding. I suppose there's always a chance methyl nitrate or something similar could form, but it seems like it'd immediately decompose on its own.
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[*] posted on 30-4-2010 at 17:30


Six feet does not really sound like it would be enough honestly. From a legistics point of view why not have every part seperated from the other by as much space as possible. When you think in terms of fire 6 feet is not really that far considering adding a longer hose for the propane feed would be a simple addition and keep the fire risk way down.

What diameter of tubing ID and OD are we talking here for the main part of the reaction to take place? Have you calculated the pressures it can take and what it will be, and possibly could be subjected to under backfire conditions?

Given that folks have managed to make Ketene without killing or poisoning themselfs this seems more then feesible but I would keep the propane take on a long, atlest 10 feet or more feed(I'd go more). I would just love to see something like this in the workings instead of reading about its pieces in the paper.







PS: You may still want to look into the Ethylamine oxidation using oxone or simular methods just for the hell of it. There are methods out there that produce 80% solutions of DMDO which would be more then enough to produce a decent amount per run making the synthesis of EtNH2 the main money pit. Just something to consider.





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S.C. Wack
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[*] posted on 9-5-2010 at 03:22


Please continue to refuse to read Mr. H's worthless articles, and the many accessible garbage patents by him (and other retards later) which would be found by entering the original patent numbers at google patents.

I understand, since all of my art study was done with coloring books.

And shame on me for not having or getting an FTP program to upload this to scipics directory, but clearly this crap is of limited interest.

http://ifile.it/u2w59py
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[*] posted on 9-5-2010 at 08:20


Those articles by Hass et al provide a lot of useful information on how this procedure has been done, the practice for many decades has been to mix the nitric acid into the alkane using an aerosol spray mechanism :D Molten salt baths have been used to heat the reactor in laboratory practice :cool:



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Melgar
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[*] posted on 11-5-2010 at 13:52


I set up a small benchtop-size reactor today, since I was tired of waiting for packages. It bubbled propane through nitric acid in a test tube, then sent it through a glass tube with a nichrome coil wound tightly around it. Then it was bubbled into a flask. Initially, the flask had water in it, but then I used methanol, since I'm sure nitroalkanes would be a lot more soluble in that. Also, methanol has a lower boiling point so it cools the reactants more and is also easier to separate via distillation. I don't have any sort of spectrometer so I had to go almost entirely on smell. Initially, I smelled mostly acetaldehyde and formaldehyde, but after tweaking the propane pressure and the current through the coil (via a light bulb dimmer switch) the smell eventually became one I was not familiar with. Once the nitric acid is used up, I'll distill it and see what I've got.

Temperature was measured at around 350 C, but that's the outside of the tube, and just with an infrared thermometer. The coil was glowing in spots so that couldn't be all that accurate though. Occasionally, when I changed the gas pressure or the current, a drop of nitric acid would get sucked into the tube and there would be a pop and a little burst of flame. Not something that looked dangerous though.

Anyway, this will be a nice way to understand the reaction before building a bigger setup.
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[*] posted on 11-5-2010 at 14:33


I found these patents in 568/927 & 568/943

US 2780657 Process for preparing aromatic nitro compounds
nitrobenzene from benzoic acid

US 3014972 Process for the preparation of organic nitro compounds
RX + MNO2 -> RNO2 in DMSO or DMF

US 3054827
cinnamate -> nitrostyrene 25% yield col 4 table II

US 3328466 Photochromic cis-1-aryl-2-nitroalkenes
IR band 10.34 microns (trans) ex 1

US 4469904 Preparation of nitro compounds by vapor phase nitration of carboxylic acids
acetic acid -> nitromethane

US 4808747 Process for producing alkylidene compounds and arylidene compounds

US 4820881
col 1 line 37+
U.S. Pat. No. 4,210,609 and Japanese No. 45-14048 teach a method of removing
colorants from nitro paraffins by passing the nitro compound through a bed of
activated alumina ('609) or distilling the nitro compound over a bed of
activated alumina, aluminum fluoride or sodium silicofluoride. These processes
have been known to exhibit spontaneous decomposition of the substrate causing
catastrophic results.

US 7265251 Process for the preparation of nitroalkenes
Styrene + I2 + nitrite, also HI from alkyl nitrite and I2

US 3192271 Method for conversion of 1, 2-dinitro-paraffins to 1-nitroolefins
pseudronitrosite -> nitroalkene?

US 3379710 Process of preparing a nitro-nitroso dimer from an olefinic hydrocarbon and a mixture of NO and NO2

US 4066699 Process for the hydrogenation of nitrated paraffins using a palladium on carbon catalyst characterized by a low ash and a low halide content



[Edited on 11-5-2010 by Vogelzang]
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[*] posted on 14-5-2010 at 14:56


Vogelzang,

Thank you for the references! Vapor phase nitration of carboxylic acids looks interesting!
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[*] posted on 16-5-2010 at 06:25


I don't know if this idea has already been ditched for another or this suggestion made, but how about lining the insides with a layer of silver?

They used to do that at the plants where they were making nerve agents after the second world war and during the cold war, given the stuffs propensity to dissolve through the pipe work and then blast the staff in the face. Mmm, steaming hot sarin... that's going in the accident book alright!

The minute you start dealing with temperature or pressure you're in trouble, combine the two together and add strong reacts and damn... I'll pass; unless I'm getting mondo cash for the privilege.

That looks like a Bunsen burning doing the cooling. A hose? :P

Google for "hcl generators report" and click the second link, the pdf 'Hydrogen Chloride Gas Generators Associated with Clandestine Drug Labs'

That's some interesting reading on combining heat, pressure and corrosive materials together.

It's also pleasing to see that even when they tried to ruin one they couldn't drive the pressure up very high at all. The corrosion on the inside of the cylinders probably retards the rate of failure to some extent.

But this is still not as bad as 400C, 150psi and nitric acid.

If you're going to try this, DO NOT try it anywhere near a house or anyone else; that's just ridiculously irresponsible. I'd also cover is with something to reflect any kind of burst escapee.

[Edited on 16-5-2010 by peach]
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[*] posted on 18-5-2010 at 05:57


Actually, I'd toned the design down to not be pressurized. As it turns out, the only reason for the pressure was so it was easier to separate unreacted propane.

I don't suppose it'd be possible to do some sort of kolbe electrolysis with a propionate salt and sodium nitrite? Presumably with an excess of propionate, since it's cheap and would boil away as butane.

I set up another setup, and am getting a strong nitroalkane smell, but only like 1 mL per hour. It uses reactants at a really low rate though. Of course, this is with 5mm OD glass tubing, so maybe I need to up the tubing size?
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[*] posted on 18-5-2010 at 07:14


Probably better to come up with a design using multiple tubes in parallel. If you scale it up you need a good heat exchange to get fast temperature ramping. Relatively short contact times are desirable, and large diameter tubes will make it difficult to get quick uniform heating without strong mixing and high space velocities. This even more so with glass as it is not a real good conductor of heat.

I note that some versions of this process keep the alkane and HNO3 separate until they are at or near the reaction temperature, the HNO3 being carried in a stream of N2 instead of alkane. Both gas streams go through a preheater, then into the reaction chamber where they are mixed, and afterward exiting the heated reaction chamber a spray of cold water is used to quench the gases.



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[*] posted on 18-5-2010 at 13:02


peach - oh, silver has a really strong reaction with nitric acid, btw. That's why I was hoping titanium would work. Though, now I'm not sure if it would catalyze oxidation reactions or not. The one paper says that heavy metal oxides catalyze oxidation, but I'm pretty sure titanium isn't in that category.

not_important - I guess multiple parallel tubes could be another way to go. I found that the reaction takes place mostly in the first five inches of the tube (that's what she said!) and so making it longer would seem to be counterproductive.
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[*] posted on 18-5-2010 at 20:53


Longer tubes would require higher gas flow rates then. You also may need better condensing, you may be losing product in the exit gases.

You're seeing a disadvantage of gas phase methods, the volumes needed - 22.4 liters/mole at STP as a rough number. Your ml of product would have occupied 300 cc as a gas. That's the other reason for higher pressures, run at 10 bar and you have 10 times the concentration of reactants and products.


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[*] posted on 18-5-2010 at 21:42


id try one of these if I was to try something like this.

http://cgi.ebay.com.au/Quartz-Tube-25mm-OD-x-1000mm-1-D-x-40...




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[*] posted on 18-5-2010 at 22:35


Even 25 mm diameter might be too large, unless you inserted something to insure the gases swirled so as to be uniformly heated by the wall. You also need a fairly fast gas flow, as it looks as optimal contact times is no more than 1 second. That suggests a gas flow rate on the order of 100 ml/sec for such a tube.

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[*] posted on 18-5-2010 at 22:39


Quote: Originally posted by Ephoton  
id try one of these if I was to try something like this.

http://cgi.ebay.com.au/Quartz-Tube-25mm-OD-x-1000mm-1-D-x-40...

I have a couple of burnt-out HPS bulbs, I wonder how hard it'd be to scavenge the alumina arc tubes out of those things? Heck, I could probably go down to my local hydroponics shop and get some bigger ones easily enough. The biggest one I have now is probably 1/4 inch ID and 6 inches long.

As far as flow rates, my propane source is still one of the little hand torch tanks. I haven't moved up to a barbecue grill tank yet, although I plan to once I have a better idea of what my design needs to be capable of.
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[*] posted on 25-5-2010 at 03:33


if i may make a suggestion, it would appear that the challenges involved are not with the chemistry rather with the engineering and as such it seems reasonable that once you have your system setup you run it with water in place of nitric acid and compressed air in place of propane. you can safely run it for several hours giving you ample time to assess flow rates, contact times, condensing efficiency etc, detect leaks, and get accurate internal temperatures, ir thermometers are hopeless with glass/quartz, you need to get a thermocouple in there during the non corrosive run as a minimum to garner a ballpark. Vapour phase is very sensitive to all the things NI has referred to and temperature is not something you want to run blind on.
Additionally do not rely on the out-coming gases throughput into a liquid to condense, you will setup all sorts of ununderstandable (thats a word i just made up) and varying pressure gradients through your system. An alternative decent condenser system if you are just trying to ascertain basics without setting up properly would be to place a large cooling chamber made of anything you have handy that can survive the conditions that your exit flow runs into just to take the brunt off the exhaust then grab a block of the coldest ice you can find and lengthwise drill holes in it, this will go at the outlet of your cooling chamber, sit the outlet pipe from the cooling chamber several inches into the block. If possible the cooling chamber should have the entry gases coming in at the top and exiting at the bottom, if you can get a round one set it up to generate a swirling path to maximize the pathlength. Thawing ice is an excellent surface for condensing. perhaps i should have made some paragraphs, apologies.




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[*] posted on 25-5-2010 at 05:58


Angus Chemicals , a subsidiary of Dow Chemical Co. since June of 2000 is the only
domestic manufacturer of Nitromethane. Angus makes just one grade of 98.4% pure
Nitromethane in a plant in Sterlington Louisiana for industrial use , car racing , and a
small amount devoted to RC model use. Prospective resellers and manufacturers are
subject to review and are eligible to receive bulk shipments only if approved by Angus.
The Angus plant produces Nitroalkanes on an industrial scale by vapor phase nitration
of Propane under pressure at up to 475 ºC. The resulting mixture of nitroparaffins ,
unreacted feed stock , and waste by products ( water, hydrogen , nitric oxide and
carbon monoxide and dioxide ) are then separated by filtration , distillation , and
other chemical processes into individual product lines and by products. Accordingly
composition of the production yields 25 % Nitromethane , 10 % Nitroethane ,
40 % 2-Nitropropane , and 15 % Nitropropane. Commercial Nitromethane thereby
contains residual amounts of Nitroethane and Nitropropane isomers as impurities.
The product also has trace amounts of Formaldehyde , Acetaldehyde , Methanol and
Ethanol. Nitromethane itself is affected by photodecomposition , and breaks down
slowly on exposure to light. Nitromethane is chemically stable when kept in the dark
at room temperature sealed in brown bottles or cans. Some Nitromethane fuel is tinged
yellow because it has an indicator dye in it. VP Racing Fuel brand Nitromethane has
this yellow dye. The purpose of it is to alert you if it has been accidentally sensitized.
Sensitized nitro does not burn , it explodes. If it turns blue or green it is sensitized.
Chinese bulk manufacture of Nitromethane relies on the method of synthesis used for
obtaining reagent grade product directly from precursors Dimethylsulfate and NaNO2
in a water slurry. It is obtained in 57 % yield when 1 mol of Dimethylsulfate is added
to 1 mol NaNO2 in a saturated water solution and mixed cold until the first stage is
completed when a second mol of of Nitrite is added. The reaction is carried at or below
20 ºC to limit formation of coproducts , primarily methyl nitrite and an aqueous solution
of Na2SO4. The mixture is then distilled at reduced pressure. Nitromethane is initially
obtained over 96 % pure , the primary contaminant being water. This and other residual
by products are removed in a two stage batch distillation. The resulting product is then
greater than 99 % having less than 0.1 % water.
These processes are outlined in Vogels Practical Organic Chemistry 3rd Editon on
pages 302 & 303. The lower yield preparative method using Chloracetic acid and NaNO2
is given on page 307. The purest Nitromethane is obtained as the sole product of
the reaction of Methyl Iodide on Silver Nitrite.

.
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[*] posted on 26-5-2010 at 02:25


Panache - thanks for the tip. It makes sense that there would be pressure fluctuations as the bubbles moved out the tube, and in fact I noticed some effects of pressure fluctuations due to the propane bubbling through nitric acid.

I had to move out of where I lived last week before I could do any more of this experiment, but I'll start again once I get a new place. In the meantime, more theory! Nitroethane seems to be the most popular product among the nitroalkanes, probably because it can't be purchased, so it'd be nice if it could be produced as the major product instead of a minor product. However, I've read a lot indicating that if ethane is used instead of propane, nitroethane is something like 85% of the yield. I'm wondering if it's worth it to set up an electrolysis cell with glacial acetic acid. Supposedly, the gas bubbles coming from the cathode are one part ethane for every two parts CO2. Electrolysis can be kind of slow, so I was thinking really big electrodes to increase surface area. I don't think CO2 interferes with this reaction, so this could work, not to mention the fact that the vast majority of the GAA ends up turning into a gas. Of course, GAA could interfere in the reaction a little, so the electrolytic cell should be kept cold too.
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[*] posted on 26-5-2010 at 12:13


Ethane can be easily and safely purchased from any decent refrigeration supplier, it is expensive though, around $150/kg because of its high purity, it is used in ultra low freezers in the second stage compressor.
Or you could move to where i live in Australia, our town gas is 5% ethane, 95% methane, easily separable, however the methane would need to be burnt/vented, not very good for our warming planet. Perhaps you could plant some trees to offset it.




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[*] posted on 31-5-2010 at 03:04


maby if some one can get a hold of this paper it may help :)

http://pubs.acs.org/doi/abs/10.1021/ie50407a004

Recent Developments in Nitroparaffins
H. B. Hass
Ind. Eng. Chem., 1943, 35 (11), pp 1146–1152
DOI: 10.1021/ie50407a004
Publication Date: November 1943




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[*] posted on 31-5-2010 at 07:46


sorry S. C wack im a dumb ass :)

nice find there still you were hinting at it when the thread first started :).

ill make sure I read more of your posts you must think me a total prat.




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[*] posted on 3-6-2010 at 10:59


I've been thinking about the idea ever since I busted the myth of so called "one pot TNT snyth" but never had the balls to try it out, as the MSDS of the hexane says, that Nitrogen oxides are form explosive mixtures with it.

When you pour together hexane and nitric acid which contains water, and boil it, the condensate will be consisting of HNO3+H2O+Hexane of given proportions. This gas mixture would be fail proof, that is the hexane will be in large excess no matter what you do. So the reaction would not end up in a Kaboom.

Any ideas to make this method failproof? I am still do not feel this reaction safe enough to try it out:(
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[*] posted on 17-6-2010 at 22:52


This patent might be interesting to some here. It is a patent that gives the conditions to produce a mixture of 83% nitroethane and 17% nitromethane by vapor phase nitration of propyl nitrite with 50% HNO3 vapor at 400*C (or NO2 at 300*C), at atmospheric pressure. Interestingly, they use an aluminum tube immersed in a molten salt as the reactor. It is advantageous because it results in a simpler mixture of products that should be much easier to purify... Assuming you can get n-propyl alcohol, propyl nitrite is ultra easy to synthesize.. The extra carbon is lost as formaldehyde. If you wanted nice pure nitromethane, you could use isopropyl nitrite instead, which results in only nitromethane (and acetaldehyde byproduct).

[Edited on 18-6-2010 by 497]
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[*] posted on 26-6-2010 at 15:00


I also read a patent in which an olefin, preferably propylene was used to produce nitromethane, the olefin carbon backbone is oxidized and the methyl group is cleaved to afford nitromethane.

I tried to reproduce the patent but the whole setup exploded to the stratosphere. IIRC they failed to mention that the propylene is react even with COLD! nitric acid (or rather it is evident for everyone just I am the fucktard..), so when I jerry rigged the setup and started it, a lot of nitric acid droplets made into the hot tube because of the exoterm and frothing, which are initially caused loud cracking noise then made small explosions then detonated the whole tube.

I also tried out the nitration of higher paraffins, I used lighter filler gas (30%propane 70% butane). The setup was made of a bubbler and a quartz tube with kanthal wire connected in serial. by adjusting the heat of the tube and the flow rate of the combustible, three different stage could be attained (the bubbler was @ room temp).

1, it was like, when you drop ethanol to cc HNO3 + H2SO4 mixture.
2, a LOT of formaldehyde.. not acetaldehyde.. I am very familiar with its smell.
3, Something that I cannot smelled before, so I cannot really describe it properly.. carrot comes to mind.

I have all the necessary glassware to make it on large scale.. and I definitely will sometime.. maybe I should wait till new years eve:)

[Edited on 26-6-2010 by Jimmymajesty]
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[*] posted on 2-7-2010 at 11:45


I repeated the experiment again on small scale today, to find it out how can you make the reaction to explode.

Here is what CANNOT be followed: I slowly bubbled butane into the nitric acid, and started to heat it, when the nitric acid was about to reach its boiling point, and NOx fumes are started to appear above the acid, I turned up the butane flow, in almost each case, a peculiar sound could be heard before the explosion, it was like when you blow a whistle.
I do not know if it could be noticed even on large scale, in this experiment the glass tube inner diameter was only 1mm.

I am going to try it out in the fortcoming 2-3 weeks and post the results, I hope not only formaldehyde that can be obtained this way, since I almost choked at every trial, in spie of that it was done outside.
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