07-26-02 06:10
No 337221
I have noticed alot of posts about hydrogenation, both with H gas, and with the microwave CHT method. I have noticed one of the main dangers or concearns with the use of this method is the explosion of the reaction flask, and accordingly the hydrogen within. My solution top this, and I asume a professional labs solution is to use some thing that has little likely hood of exploding, is quartz glass flasks. For the microwave method it appears there would be a better transference of microwaves anyhow here is something I found on quartz glass that may help out in your decision. Also they make almost every piece of lab glassware from quartz, and it bearly costs more.
Cy
PROPERTY:
Density 2.2 gm/cm3
Hardness 5.5–6.5 Mohs’ Scale
Design Tensile Strength 7,000 psi
Design Compressive Strength 160,000 psi
Bulk Modulus 5.3 x 106 psi
Rigidity Modulus 4.5 x 106 psi
Young’s Modulus 10.5 x 106 psi
Poisson’s Ratio .17
Coefficient of Thermal Expansion 5.5 x 10-7 cm/cm • °C(20°C – 320°C)
Thermal Conductivity (20° C) 3.3 x 10-3 gm cal
Specific Heat (20°) .16gm cal/gm
Softening Point 1683°C
Annealing Point 1215°C
Strain Point 1120°C
Electrical Resistivity 7(107) ohm • cm 350°C
Dielectric Properties (20°C and 1 MHz) Constant 3.75 3.75
Strength 5 x 107 volts/mil
Loss Factor Less than 4 x 10-4
Dissipation Factor Less than 1 x 10-4
Index of Refraction 1.4585 1.4585
Velocity of Sound-Shear Wave 3.75 x 105 cm/sec
Velocity of Sound-Compression Wave 5.90 x 105 cm/sec
Sonic Attenuation Less than 11 db/m • MHz
Permeability Constants (cm • mm/cm • sec • cm of Hg – 700°C/973°K
Helium 210 x 10-10
Hydrogen 21 x 10-10
Deutrium 17 x 10-10
We are the people that your parents warned you about.
(Old P2P Cook)
07-26-02 06:23
No 337227
My solution top this ... is to use some thing that has little likely hood of exploding, is quartz glass flasks.
I don't follow your reasoning.
Also they make almost every piece of lab glassware from quartz, and it bearly costs more.
That is news to me.
(Hive Bee)
07-26-02 07:49
No 337267
The likely hood of explosion would not be reduced, however, if it were to occur it would be contained, also I have seen alot of expression of concearn for explosion of a flask under pressure, this definately cirumvents that problem. As far as the cost although it is about twice as much, I guess in my opinion an extra $100-200 per flask is not much more, other bees may have differing opinions on that. As usual I was just \telling you what works for me, take what you want and leave the rest.
Anyhow,
Cy
We are the people that your parents warned you about.
(Old P2P Cook)
07-26-02 08:27
No 337282
if it were to occur it would be contained, also I have seen alot of expression of concearn for explosion of a flask under pressure, this definately cirumvents that problem.
That is what I thought. So, you somehow think that a quartz flask is going to be orders of magnitude stronger than a glass flask. I don't think so. Why do you think this?
As far as the cost although it is about twice as much,
Just twice, eh? Again, where do you get this number?
(Hive Bee)
07-26-02 09:12
No 337296
A quick orice comparison:
Borsilica Round bottom flask:
500ml $73
1l $106
2l $209
Quartz RBF:
500ml $169
1l $246
2l $426
Don't know what you are talkng about.
Cy
We are the people that your parents warned you about.
(Hive Bee)
07-26-02 09:50
No 337318
So you think/assume that a quartz reaction flask of the the same size and wall thickness as a regular borosillicate reaction flask will hold an eventual hydrogen/oxygen detonation.
I don´t think so....Instead of trying to figure out what material can withstand a explosion, focus that energy towards issues such as not allowing oxygen coming into the reaction system.
(Official Hive Approximator)
07-26-02 09:54
No 337321
> Borsilica Round bottom flask:
> 500ml $73
these are _not_ US$, are they!?
for that price you should get a whole distillation apparatus
with column from your local friendly glasblower!
official gene trash
(Hive Bee)
07-26-02 10:53
No 337333
Heavy walled borsilica
We are the people that your parents warned you about.
(Stoni's sexual toy)
07-26-02 10:55
No 337335
Hypo, that might very well be US-$. There seems to be a huge conspiracy among all the US glass blowers, they all charge at least 2-3 times the money over there compared to european prices.
If it wasn't for incompatible joint sizes I already would have set up an glassware export business.
I'm not fat just horizontally disproportionate.
(Hive Bee)
07-26-02 12:13
No 337351
There is a huge diffrence between being able to withstand a pressure of 7000psig being genersted by opening a gas tube slowly and being able to withstand a detonation.....
(Hive Bee)
07-26-02 12:57
No 337357
You think a quartz flask could stop this?
I understand the physics of it, but I still think i was at least a good idea wasn't it. . . .
Cy
Cy
We are the people that your parents warned you about.
(Stoni's sexual toy)
07-26-02 13:29
No 337365
> Design Tensile Strength 7,000 psi
> Design Compressive Strength 160,000 psi
This has NOTHING (well, almost nothing) to do with how much pressure your vessel can endure. These are merely values characterising the physical properties of quartz as a material for comparison to other materials. There is a BIG difference!
I'm not fat just horizontally disproportionate.