WSM Posted July 24, 2014 Posted July 24, 2014 I never knew about this device, but it seems perfect! I'm in South Africa so getting one might be tricky. I might have to build my own. Your best bet might be to search eBay. Some of the best values seem to be from China. Good luck! WSM
WSM Posted July 24, 2014 Posted July 24, 2014 I've used cellulose and glassfiber filters in the past. They both work about the same for applications like this. I find cellulose fibers to be stronger when dry, and glassfiber stronger when wet. Cellulose is probably considerably cheaper, but Glassfiber is also considered reusable. You can almost certainly reuse cellulose thimbles though. One trick is to let them dry in the extractor before removing them. Cellulose is compatible with most normal things we'd use. Just watch out for strong oxidizing agents and strong acids and bases. The only thing that might cause an issue here is possibly any remaining dichromate additives, unless you somehow generate perchloric acid or a bunch of hydroxide. Have you ever considered one of those glass thimbles with the frit in the bottom? What extra precautions may be involved in using them, or do you just drop it in and go? I've wondered if it's prudent to use filter paper with one? Any idea? WSM
Arthur Posted July 24, 2014 Posted July 24, 2014 If you are blowing your own glassware then make it big enough to fit a coffee filter!
Mumbles Posted July 24, 2014 Posted July 24, 2014 I don't think the fritted glass thimbles are designed to be used this way, but if you can find one of the right size it seems like a great idea! The fritted glass thimbles you're talking about are actually called Gooch crucibles. My undergrad always used to giggle at the name. The high form Gooch cruicbles would probably be most ideal for this application. My biggest concern would be flow rate. The cellulose and glassfiber ones are fairly porous and have good flow through them. A Gooch crucible is really only designed to have fluid flow out the bottom. I'd worry about them either floating in a pool of solvent around them, or filling directly and spilling the solid contents out into the rest of the reservoir. For a soxhlet to really operate correctly, they have to fill pretty evenly inside and outside the thimble. That way when the reservoir fills past the siphon point all of the solvent is pulled out both inside and outside the thimble. It's not a problem for the solution to be pulled out only the bottom of the thimble, but I'd worry about the siphon breaking before all the solvent could be filtered though.
MrB Posted July 24, 2014 Posted July 24, 2014 Shouldn't that just keep the "cup" somewhat filled, and the cycle would repeat faster then it would have needed other-ways? Of course, the siphon has to engage low enough (under the edge of the cup) so that it engages before the "cup" overflows. Balancing this could prove tricky, but getting it wrong, in the direction that it engages to early, shouldn't really matter...This animation seams to suggest that it's acceptable. I guess the turbulent flow of a faster drain is preferred, but it should work regardless.B!
Mumbles Posted July 24, 2014 Posted July 24, 2014 You can see in the animation that the solvent drips directly into the thimble. This is sort of true in practice, but there is also a considerable amount that just condenses on the walls and drips down too. You can see after the reservoir drains, the solvent in the thimble equalizes out immediately. This is the part I'm concerned about. That the solvent will be able to drain out the bottom before it fills up enough to overflow. There just needs to be enough exchange between solvent inside the thimble and outside that it actually extracts something. My experience is that glass frits don't filter very quickly at atmospheric pressure, really needing some vacuum to do the trick quickly. In practice it works kind of like in the animation, but the solvent can flow out of all sides of the thimble. The thimble also drains somewhat when the reservoir goes as well.
MrB Posted July 24, 2014 Posted July 24, 2014 Cool. Thank you for explaining. It's a simple device, now that one has seen it, but who ever came up with it in the first place really wasn't afraid of thinking outside the box. The "thimble" could drain as fast as the reservoir, i suppose, but there is probably a sweetspot where the amount of fluid returning down to get reheated isn't enough to cool the content being heated already. If i ever decide to start collecting esoterica, weird lab equipment will be one of my first priorities. And a kit of these is a must have at that point. They even look cool. Freaking wonderfull.Thanks again.B!
schroedinger Posted July 25, 2014 Posted July 25, 2014 Mumbles the glass frit timbles work beatyfull, but there are some points you have to watch out when using them. First you can just apply very gentle heat to get just a slow droprate from the condenser, 2nd you need to use the fritt with the biggest pore available, to get a god flow of soovent, also its best to use a really high timble witch stopps just about 2" in front of the condenser. But better are dimples with a simple hole plate (hole size about 1 mm) and inserting a smal pice of a filter into the timble.
WSM Posted July 28, 2014 Posted July 28, 2014 I just received the July, 2014 PGI Bulletin, which contains the article, Homegrown Oxidizers, Part V. If any active PGI members see it, feel free to comment here. Thanks. WSM
taiwanluthiers Posted July 28, 2014 Posted July 28, 2014 Ok I just googled the frit extractor... so let's say if potassium chlorate is not at all soluble in ethanol, and chloride is barely soluble in ethanol (I am not saying they are by the way), then I could use it to purify chlorate? Where can I find a chart listing the solubilities of various important oxidizers in various solvents besides water?
WSM Posted July 29, 2014 Posted July 29, 2014 Ok I just googled the frit extractor... so let's say if potassium chlorate is not at all soluble in ethanol, and chloride is barely soluble in ethanol (I am not saying they are by the way), then I could use it to purify chlorate?Where can I find a chart listing the solubilities of various important oxidizers in various solvents besides water? Besides using a Google search for each of the individual oxidizers, and developing your own list; you can look up the information in sources like: the CRC Handbook of Chemistry and Physics, or theMerck Index which may be found in a public library. Buying copies of your own (even old or used copies) are excellent references to have on hand and valuable resources. Good Hunting. WSM
pyroChile Posted July 30, 2014 Posted July 30, 2014 Where can I find a chart listing the solubilities of various important oxidizers in various solvents besides water? Hello taiwanlu! here is a book, I hope you serve. aqueous solution and diagram.pdf Best regards, =)
rogeryermaw Posted July 30, 2014 Posted July 30, 2014 soxhlet extractors can be very expensive. if you are patient and observant, there is a much cheaper alternative. i use a 24/40 setup with a 1 liter boiling flask, a 500 ml pressure equalized dropping funnel and a 200 mm liebig condenser cooled with a 5 gallon bucket of ice water and a fish pump.the observant and patient part comes in when you have to be there to open the stopcock when the dropping funnel fills up to the equalization tube. pretty simple and effective. i have used it to extract organics but using it to exploit solubility differences never occurred to me. genius!!!@mumbles
WSM Posted July 31, 2014 Posted July 31, 2014 Hello taiwanlu!here is a book, I hope you serve.aqueous solution and diagram.pdfBest regards,=) Hi pyroChili, Thanks for sharing that volume. It looks useful. When I downloaded it and put it in a folder I discovered this: CRC Handbook of Chemistry and Physics 85th edition.pdf The file is HUGE, but certainly worth having. Enjoy! WSM
WSM Posted July 31, 2014 Posted July 31, 2014 soxhlet extractors can be very expensive. if you are patient and observant, there is a much cheaper alternative. i use a 24/40 setup with a 1 liter boiling flask, a 500 ml pressure equalized dropping funnel and a 200 mm liebig condenser cooled with a 5 gallon bucket of ice water and a fish pump.the observant and patient part comes in when you have to be there to open the stopcock when the dropping funnel fills up to the equalization tube. pretty simple and effective. i have used it to extract organics but using it to exploit solubility differences never occurred to me. genius!!!@mumbles Thanks for the alternative method of extraction. I like your creativity. The advatage of getting an actual soxhlet extractor is it's mostly automatic without much direct "hands on". You set it up and run it and your extract concentrates pretty much on it's own. Shopping on eBay shows a Soxhlet extractor can be affordable and worth saving up for (if you have a need for such things). WSM
WSM Posted July 31, 2014 Posted July 31, 2014 It's fun discussing Soxhlet extractors, but I'm thinking more about the chlorate process. I'm getting ready to remake a set of electrodes for our friend, pyrojig. Since his bucket cell ran so hot, and he had issues with the long narrow electrodes; my thinking is to make the electrodes more square (rectangle, actually), with larger diameter tubular titanium leads placed further apart, and possibly with a slightly greater gap between the anode and cathode pair. I'm planning on using 3/8" diameter (~9.5mm) titanium leads spaced about 2.125" (54mm) apart; which will match a pair of tapped ports in his BCA (bucket cell adapter). I'll probably post photos in the Bucket Cell thread when I manage to do all this... WSM
MrB Posted July 31, 2014 Posted July 31, 2014 The file is HUGE, but certainly worth having.I think your like my girldfriends. Very easy to impress. "Thats huge!" is a normal comment, to a slightly above average size... Yeah, i'm talking about the PDF again. Thanks for sharing it. I think it goes slightly outside my needs and clearly succeeds my knowledge, but i grabbed it, and stuck it in my pyro docs.B!
Bobosan Posted July 31, 2014 Posted July 31, 2014 jeez, B, perhaps you should add a disclaimer on the bottom of that mirror over your bed that reads "objects appear larger than they actually are". Might stop the apprehension those wimmin have.
MrB Posted July 31, 2014 Posted July 31, 2014 "Objects closing in from the rear might appear larger than they actually are"You know what.. I totally need to get me a mirror for the bedroom... Sort of derailing the thread tho. I'm sorry.B!
Bobosan Posted July 31, 2014 Posted July 31, 2014 Some very heavy experimentation goes on in this thread. Need a commercial break every now and then.
rogeryermaw Posted August 1, 2014 Posted August 1, 2014 It's fun discussing Soxhlet extractors, but I'm thinking more about the chlorate process. I'm getting ready to remake a set of electrodes for our friend, pyrojig. Since his bucket cell ran so hot, and he had issues with the long narrow electrodes; my thinking is to make the electrodes more square (rectangle, actually), with larger diameter tubular titanium leads placed further apart, and possibly with a slightly greater gap between the anode and cathode pair. I'm planning on using 3/8" diameter (~9.5mm) titanium leads spaced about 2.125" (54mm) apart; which will match a pair of tapped ports in his BCA (bucket cell adapter). I'll probably post photos in the Bucket Cell thread when I manage to do all this... WSM It's fun discussing Soxhlet extractors, but I'm thinking more about the chlorate process. I'm getting ready to remake a set of electrodes for our friend, pyrojig. Since his bucket cell ran so hot, and he had issues with the long narrow electrodes; my thinking is to make the electrodes more square (rectangle, actually), with larger diameter tubular titanium leads placed further apart, and possibly with a slightly greater gap between the anode and cathode pair. I'm planning on using 3/8" diameter (~9.5mm) titanium leads spaced about 2.125" (54mm) apart; which will match a pair of tapped ports in his BCA (bucket cell adapter). I'll probably post photos in the Bucket Cell thread when I manage to do all this... WSM are you planning on coating the electrodes? lead dioxide perhaps? titanium can passivate pretty quickly. if so, i'd enjoy reading about your process. i have a lab manual on coating electrodes with PbO2 if anyone needs it.
WSM Posted August 1, 2014 Posted August 1, 2014 (edited) are you planning on coating the electrodes? lead dioxide perhaps? titanium can passivate pretty quickly. if so, i'd enjoy reading about your process. i have a lab manual on coating electrodes with PbO2 if anyone needs it. His bucket cell is exclusively for converting KCl to KClO3, so it uses an MMO anode and two titanium cathodes. We're saving the PbO2 (or even Pt) for converting NaClO3 to NaClO4 and then exchange the product for whichever perchlorate is desired. I'd be happy to get a copy of your PbO2 lab manual, though. Thanks for offering !!! WSM Edited August 1, 2014 by WSM
pyroChile Posted August 1, 2014 Posted August 1, 2014 i have a lab manual on coating electrodes with PbO2 if anyone needs it. Hello roger! be interesting to see the manual, thanks for the offer. Best regards, =)
rogeryermaw Posted August 1, 2014 Posted August 1, 2014 is there a forum library or something i can upload to?
schroedinger Posted August 1, 2014 Posted August 1, 2014 (edited) Third tap on top downloads Edited August 1, 2014 by schroedinger
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