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Author: Subject: Best way for getting high density ?
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[*] posted on 28-11-2014 at 23:40


I heard you use a normall solid binder, heat to liquid, mix, pour into mold, compress, wait to solidify.
Just make sure the heating and compressing dont trigger it.
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[*] posted on 1-12-2014 at 11:53
Reflux condenser.


Cu tube 10/12, long 600mm.
Jacob's ladder condensation......:cool:...LL

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[*] posted on 2-12-2014 at 04:00


Quote: Originally posted by Laboratory of Liptakov  
Cu tube 10/12, long 600mm.
Jacob's ladder condensation......:cool:...LL



For the transesterification of castor oil? For that purpose it is overkill by function, but if one enjoys the process then why not. I personally would have just screwed the lid lightly on the glass jar to prevent the methanol from evaporating. In fact I have conducted the synthesis in an open flask without any problems and without any preventative measures to avoid the escape of methanol....it really is not that volatile by nature.




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[*] posted on 2-12-2014 at 05:44


Methanol is quite toxic and its boiling point is less than 65C. I used a long piece of glass tubing and a rubber stopper to make a simple air cooled reflux condenser the last time I performed the trans-esterification reaction indoors. The heat transfer properties of copper are very much superior to glass (and pretty much every other common material); as long as the chemicals involved in a particular application are compatible with copper it can be used. Glass is much closer to being completely inert, however, and it provided all the cooling I needed.



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[*] posted on 2-12-2014 at 07:39
methyl ricinoleate


Markx is right. No need cooler. Glasses can be closed. The steam pressure is small. Even at 80C cap holds. No problems. The temperature is maintained at 70C for 4 hours. A sample of the reaction: 19.5 g + 0.5 g of 96% H2SO4. It is necessary to wait for the separation of the layers. The lower part has to be glycerine and the upper portion of the solution of methyl ricinoleate. Distribution takes 12 hours ....? ....LL
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[*] posted on 2-12-2014 at 11:21


Quote: Originally posted by Laboratory of Liptakov  
A sample of the reaction: 19.5 g + 0.5 g of 96% H2SO4. It is necessary to wait for the separation of the layers. The lower part has to be glycerine and the upper portion of the solution of methyl ricinoleate. Distribution takes 12 hours ....? ....LL


Sulfuric acid? Did you use the acid catalysed transesterification process? Base catalysed transesterification tends to work much faster due to the reaction mechanism specifics:

http://www.icrepq.com/icrepq%2711/549-encinar.pdf

First separation of layers with base catalyst process can be observed quite quickly...in less than an hour from the start of reaction, but complete separation can take up to 12 hours (depending on ambient temperature).




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[*] posted on 2-12-2014 at 13:26
r.oleate


I followed the instructions from page 5 this thread:
methylricinoleate.pdf
Unfortunately I have bad results, methyl ricinoleate failed to produce. I will return to this later. Thank you for your help and for the last link. I need very precise instructions. Machine translation trouble. Few understand. I do not want to be a burden.
I prefer to bring results. As is detonography etc. .......:cool:....LL
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[*] posted on 2-12-2014 at 14:02
Glass Reaction Vessel Pressure Calculation


I decided to work through this, just for my own interest mostly. Assuming ideal behavior, will use Raoult's Law and Dalton's Law. I may have made calculation errors.

Information on castor oil came from this site:
http://www.scbt.com/datasheet-214671-castor-oil.html

Castor Oil - C57H104O9
MW = 933.61g/mol
Density = 0.961g/mL

Vapor pressure at 80C came from the following site:
http://www.engineersedge.com/fluid_flow/fluid_data.htm

Castor Oil Vapor Pressure at 80C ~= 0 kPa (very, very low)


Methanol - CH3OH
MW = 32.04g/mol
Density = 0.792g/mL
Vapor pressure at 80C ~= 182kPa
(Methanol values from Wiki pages)

Assume using equal volumes of castor oil and methanol as Nitro-
genes suggested here:
http://www.sciencemadness.org/talk/viewthread.php?tid=6151&a...

Basis of 100mL of each reactant

Moles of Castor oil = 100mL * (0.961g/mL) / (933.61g/mol) = 0.1029moles
Moles of Methanol = 100mL * (0.792g/mL) / (32.04g/mol) = 2.472moles

Mole Fraction of Castor oil in liquid = 0.1029 / (0.1029 + 2.472) = 0.040
Mole Fraction of Methanol in liquid = 2.472 / (0.1029 + 2.472) = 0.960

Pressure Total = Pvap_castor * X_castor + Pvap_MeOH * X_MeOH
Pressure Total = 0 * 0.040 + 182kPa * 0.960
Pressure Total = 174.72 kPa (atmospheric is 101.32kPa)

This is of course the maximum pressure at the start of the reaction at 80C; since as the methanol is consumed its liquid molar fraction will drop and so too will the internal pressure. I didn't account for the air in the head space, but its pressure will not be significant compared to the vapor pressure of methanol at 80C.

It is amazing how much internal positive pressure undamaged, well made, glass bottles can take. There is a big difference between a champagne bottle, built to handle pressure, and a thin walled pickle jar though. Also bottles, even of the same type, are never completely uniform and some have imperfections which make them much weaker. A small crack or imperfection can make a glass vessel fail at very low pressures.

Attached is a study done on glass bottle destructive testing.


Attachment: Analysis of Brittle Fracture of Soda Glass Bottles under Hydrostatic Pressure.pdf (274kB)
This file has been downloaded 665 times


[Edited on 3-12-2014 by Hennig Brand]




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[*] posted on 3-12-2014 at 00:55


174kPa would be the worst case scenario, assuming that the whole reactor is at 80C. If one uses a tall(ish) reactor with only the bottom part of reagents submerged in the thermostat then the upper part of reactor would act as a natural cooler, provoking condesation and relieving the pressure gradient significantly. And 80C in my personal experience is too much for practical transesterification. I speak of my own experiences and I have noticed that when you go that high with the temperature, you will saponify the oil, spend the hydroxide on it and are left with a sticky well emulsified mess of oil, soap and unreacted alcohols. It may look similar to transesterification at some stage, but the phase separation will never occur. So my suggestion would be to relax, turn the heat down and keep the catalyst content low. Try 40-50C and catalyst content below 1% oil mass (dissolve the alkali in the methanol beforehand). Nice mellow conditions at the expense of reaction time but no need for extra coolers, pressures will not burst reactors and ruin your day. At 50C the methanol vapour pressure should stay around 53kPa even if you submerge the whole system into the water bath.



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[*] posted on 3-12-2014 at 02:13


Sounds like good suggestions. I haven't made any in several years. I made some two or three times, around that time, and I still have quite a bit of it left.



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[*] posted on 4-12-2014 at 08:20


Maybe something could be done with PVN (polyvinylnitrate = (-CH2-CHONO2-)n) as active, unsensitive plastic binder?
Density: 1.6 g/ccm
VOD: 7000 m/s @ 1.5 g/ccm (so 7600 m/s at max density)
Impact sensitivity: 10 Nm (IS PETN is 3 Nm)

For sure much better than common oils due to density increase and partly contributing to energy output.




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[*] posted on 4-12-2014 at 12:33


As long as the desired handling properties could be obtained it sounds great. Handling properties would come first, I would imagine, when considering the binder & plasticizer components for a plastic explosive.



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[*] posted on 4-12-2014 at 13:33
PVN


In advance thank you all for your valuable contributions to methyl ricinoleate. Also: Polyvinyl Nitrate? VOD 7000 m / s and more? But: Is it possible to produce? Glue Hercules, that is polyvinyl acetate. (contains PVA) Hydrolysis in methanol polyvinylalcohol arises. Polyvinyl alcohol is esterified (HNO3) on polyvinyl nitrate. He tried to anyone? We know how to do it? Here is my best plastic .....:cool:.......VoD 0,0 m/s

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[*] posted on 5-12-2014 at 05:37


Polyvinyl alcohol pouches were used when I was working at Procter&Gamble R&D lab.
You get tiny plastic like bags with the liquid soap inside (high dutty liquid).
The liquid soap had to contain as little as possible moisture in a way to keep the bag integer, avoid leakage and mass sticking of the pouches.

The bag (owing to the hydrophilic nature of the hydroxy groups (PVA = (-CH2-CHOH-)n) dissolves into the wash-machine when in contact with warm or tempered wash-water and set the washing liquid free into the hart of the clothes...

This technology is now common to encapsulate soaps for clothes and for dishwashing powders... ;)
So now everybody knows where to look for it :D




[Edited on 5-12-2014 by PHILOU Zrealone]




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[*] posted on 5-12-2014 at 07:30


Very nice PHILOU, could you tell us a little bit about producing Polyvinyl Nitrate? It sounds like you have been through it and know what you are talking about.



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[*] posted on 5-12-2014 at 09:57


Same procedure as for polyols like cellulose nitrate, PETN, ETN.

Related compounds are ethyl nitrate, trimethylene glycol dinitrate and 1,3-butanediol dinitrate as being non viccinal nitric esters...there is a CH2 bridging between C holding a nitrate groupe.
H-(-CH2-CHONO2)n-H
n=1 CH3-CH2ONO2 = ethyl nitrate
n=2 CH3-CHONO2-CH2-CH2ONO2 = BGDN
n= Big = PVN
This family of compounds is linked to PETN family where the brindging is a C atom...they display good performances with low sensitivity to shock vs parent pernitrated polyols with one nitrate per C atom

[Edited on 5-12-2014 by PHILOU Zrealone]




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[*] posted on 5-12-2014 at 11:50
polyvinylalcohol


Well done Phil. This is very important information. Polyvinyl Alcohol is thus a solid mass? A little plastic? It will be possible to use the empty container clean? A basic mixed acid? HNO3-65 / H2SO4-96%? 40:60? That's all? The reaction temperature to 5C as ETN? Or 25C like PETN? The package will be dissolved. Prior to esterification. Very interesting ....:cool:....LL
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[*] posted on 5-12-2014 at 12:34


Working with castor oil is problematic, because you can also transesterify to the alcohol group on the fatty acid chain. You need a very large excess of methanol to avoid this. Also, usage of sulfuric acid will lead to ricinoleylsulfuric acid, where the alcohol is converted to a monosulfonate ester. The sodium salt of this material is called turkey red oil and is a historically used surfactant in dying processes.



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[*] posted on 6-12-2014 at 04:29


Polyvinyl alcohol with different degrees of polymerisation is commercially available in powder form....no need to scavange and grind up the sufactant capsules to obtain it :)

E.g.

http://www.carolina.com/specialty-chemicals-p-r/polyvinyl-al...

http://www.amazon.com/Polyvinyl-Alcohol-Purity-Powder-Bottle...

Just pick a source and order a sample...

It is widely used to encapsulate redispersion powder particles to prevent premature hardening during storage.




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[*] posted on 6-12-2014 at 07:12
Polyvinyl nitrate


Good work markx. We're only a small step from perfect plasticizer. And that's not all. Polyvinyl nitrate can be used independently. Or widely represented in the mixture. Excellent substance. Universal. I hope to see you soon ....:cool:
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[*] posted on 6-12-2014 at 07:39


As a matter of fact I think that I still have a rather sizeable sample of POVAL brand PVOH powder somewhere in my lab....gotta keep an eye out for it. Was not much good for the purpose that I ordered it, but perhaps the "alternative use" shall prove more successful.



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