On Behalf Of Daniel Kuespert
Sent: Thursday, August 29, 2019 2:27 AM
To: DCHAS-L**At_Symbol_Here**PRINCETON.EDU
Subject: Re: [DCHAS-L] Hydrothermal and solvothermal reactor safety** External Email **
Lots of good suggestions here; I think I‰??ll forward this thread to some of our researchers who do hydrothermal work.
One thing that hasn‰??t been mentioned is reviewing the reagents and solvents for thermal decomposition hazards. I am aware of an incident where a Parr bomb (tradename used generically; can‰??t remember the brand) burst its rupture disk during unattended heating overnight in an oven, dumping into the lab. Although the PI and I disagree on the exact source of the overpressure, I believe it was thermal decomposition of the DMSO solvent, a known phenomenon at the temperatures involved. The smell of ‰??microwaved broccoli‰?? permeating the building (dimethyl sulfide or dimethyl disulfide, I‰??m guessing) was apparently memorable.
The other candidate for the cause was some HDPE that was present acting as a reducing agent on the reaction mixture. So a healthy respect for the fact that you get different reactivity at elevated temperature and pressure, and things you think of as ‰??inert‰?? may not be.
Regards, Dan Kuespert
Sent from my iPad
> On Aug 28, 2019, at 21:01, davivid wrote:
>
> Although Parr equipment is quite popular, I prefer Autoclave Engineers.
>
> https://nam05.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.a
> utoclave.com%2F&data=02%7C01%7C%7C9d0ac15c840d42f1183708d72c6d29c4
> %7C994c3e8bb42845fb8640593ef0303f7f%7C0%7C0%7C637026719677544041&s
> data=1xuG%2BUIyvE2pfrFzEENVw4om50hrJ6Yc23w5FEolKgs%3D&reserved=0
> https://nam05.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.a
> utoclaveengineers.com%2F&data=02%7C01%7C%7C9d0ac15c840d42f1183708d
> 72c6d29c4%7C994c3e8bb42845fb8640593ef0303f7f%7C0%7C0%7C637026719677544
> 041&sdata=8qjVTFFsEbqxx4Y64N%2BGnVbeGOs0HuWlYpWedlguS30%3D&res
> erved=0
>
> Dave Lane
> Principal
> Clavis Technology Development
>
>> On 8/28/19 3:15 PM, Yaritza Brinker wrote:
>> Hi Jeff,
>>
>>
>>
>> I‰??ve purchased and used pressure bombs. The models I‰??ve used are
>> bigger‰?| 1L vessels with pressure gauge and temp probe. However, I do
>> know that Parr offers PTFE lined small vessels with Safety Blow-Off
>> that can be used as hydrothermal reactors.
>>
>>
>>
>> https://nam05.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww
>> .parrinst.com%2Fproducts%2Fsample-preparation%2F&data=02%7C01%7C%
>> 7C9d0ac15c840d42f1183708d72c6d29c4%7C994c3e8bb42845fb8640593ef0303f7f
>> %7C0%7C0%7C637026719677544041&sdata=C7EymFlrUBwNBhchUZdNA%2FIxKgc
>> ReX9MigTeNIptqIY%3D&reserved=0
>>
>> https://nam05.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww
>> .parrinst.com%2Fdownload%2F37527%2F&data=02%7C01%7C%7C9d0ac15c840
>> d42f1183708d72c6d29c4%7C994c3e8bb42845fb8640593ef0303f7f%7C0%7C0%7C63
>> 7026719677544041&sdata=5A6qEiiS2n5N1SxNu1iMUilwXtgm3hFyudf5oSx245
>> 8%3D&reserved=0
>>
>>
>>
>> Here‰??s what I learned from using the 1L capacity‰?|
>>
>> * It is safer to spend the extra money and go for a model with a
>> Pressure Gauge.
>> o `This will help you ensure that‰?|
>> + you don‰??t over pressurize the system
>> + you don‰??t open the system before it is completely cooled
>> * A temperature probe is nice to have.
>> o If you intend to heat the system, your heat source should have
>> ramp control and temperature readout. If not, then the temp
>> probe basically becomes required.
>> o For Teflon lined units, you want to keep your system below the
>> temp/pressure where Teflon softens.
>> * Don‰??t use materials that are known to be incompatible with the
>> vessel‰??s interior (goes without saying, but you‰??d be surprised)
>> * Look around the area for any other pieces of equipment that could
>> cause a larger combined hazard if the vessel fails.
>> o i.e. if your pressure vessel has water in it, don‰??t use an oil
>> bath as your heat source (you‰??d be surprised here too)
>> * Before each use, inspect
>> o the seals for any signs of hardening, cracking, or softening.
>> o If PTFE lined, inspect that too.
>> o the fasteners for any signs of cracking or elongation.
>> * Do not over torque it as this can damage the lip seals and cause
>> elongation (weakening) of the fasteners
>> * Ensure the vessel is back to room temperature before opening.
>> o This is where the temperature probe comes in really handy.
>> + Also, PTFE is a plastic and as such acts as a thermal
>> barrier. Your metal outer may be cool to the touch, but the
>> inside can still be hotter that you‰??d think.
>> o In the past I‰??ve routinely let the vessel cool down overnight
>> and also ensured the pressure gauge was back to ‰??0‰?? before opening.
>> * For shielding, we used a latched oven. That particular oven had
>> ports we could use to monitor the bomb. We added a containment pan
>> at the bottom of the oven just incase of spillage.
>> * Cooling and heating rates should always follow the manufacturer‰??s
>> recommendations‰?| these are tied to the metal alloys used, the metal
>> thickness, and seal design.
>> * Always have a lab buddy monitoring from a safe distance when opening
>> the unit‰?| just in case it goes south.
>>
>>
>>
>>
>>
>> Hope this helps.
>>
>>
>>
>> Yaritza Brinker
>>
>> 260.827.5402
>>
>>
>>
>> *From:* ACS Division of Chemical Health and Safety
>> *On Behalf Of *Jeffrey Lewin
>> *Sent:* Tuesday, August 27, 2019 12:01 PM
>> *To:* DCHAS-L**At_Symbol_Here**PRINCETON.EDU
>> *Subject:* [DCHAS-L] Hydrothermal and solvothermal reactor safety
>>
>>
>>
>> *** External Email ***
>>
>> I'm looking for any information on the safe operation of hydrothermal
>> and solvothermal reaction chambers. They are sometimes also referred
>> to as "autoclaves" (different than what this biologist thinks of) and
>> "bombs." which might be the best description having recently viewed
>> pictures of one that catastrophically failed (no injuries, plenty of
>> damage).
>>
>>
>>
>> From what I can find Googling - they've been around commercially for
>> some time (10 or more years?); I found very little in written SOP's,
>> but the discussion on researc- gate I've seen several comments that
>> if not handled correctly, the results can be energetically problematic.
>>
>>
>>
>> See
>> https://nam05.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww
>> .toptionlab.com%2FHydrothermal-synthesis-reactor%2Fteflon-lined-hydro
>> thermal-reactor.html&data=02%7C01%7C%7C9d0ac15c840d42f1183708d72c
>> 6d29c4%7C994c3e8bb42845fb8640593ef0303f7f%7C0%7C0%7C63702671967754404
>> 1&sdata=1apB3W16bQYpMrAb%2Bb40EC61Z2hs9xGuLTmFdgxLBJ4%3D&rese
>> rved=0
>> <https://nam05.safelinks.protection.outlook.com/?url=https%3A%2F%2Fww
>> w.toptionlab.com%2FHydrothermal-synthesis-reactor%2Fteflon-lined-hydrothermal-reactor.html&data=02%7C01%7C%7C9d0ac15c840d42f1183708d72c6d29c4%7C994c3e8bb42845fb8640593ef0303f7f%7C0%7C0%7C637026719677544041&sdata=1apB3W16bQYpMrAb%2Bb40EC61Z2hs9xGuLTmFdgxLBJ4%3D&reserved=0> for an example of a reactor.
>>
>>
>>
>> So questions for the group:
>>
>>
>>
>> Does your institution have specific guidance on using these such as
>> limiting the size of reaction chambers?
>>
>>
>>
>> Do you have minimum engineering controls for containment (blast
>> shielding, etc.)?
>>
>>
>>
>> Does your institution explicitly prohibit using them?
>>
>>
>>
>> Two critical administrative controls I've seen are:
>>
>>
>>
>> 1) not overfilling the reaction chamber, allowing headspace for gas
>> formation. For hydrothermal reactions, this seems pretty well
>> established since water expands about 25% at the temperatures these
>> are operating at (190-220C). For solvents, it doesn't seem to be as
>> straight forward. For example, I've not been able to find an
>> expansion factor for dimethylformamide (DMF).
>>
>>
>>
>> 2) not heating and cooling too fast. The instructions I've seen with
>> reactors say things like don't heat or cool faster than 5C/min. But
>> I've seen instructions that go outside those guidelines (8C/min) and
>> several that say "cool naturally" i.e. not at 5C/min (I've also seen
>> discussions that specifically advise against quenching them).
>>
>>
>>
>> Any insight would be appreciated.
>>
>>
>>
>> Jeff
>>
>>
>>
>>
>>
>> --
>>
>> Jeff Lewin
>>
>> Chemical Safety Officer
>>
>> Research Integrity Office
>>
>> Laboratory Operations
>>
>> 207 Advanced Technology Development Complex (ATDC)
>>
>> Michigan Technological University
>>
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