(Hive Addict)
06-08-04 23:17
No 512239
(Rated as: excellent)
The one million $ question is: what would be the best kitchen-method to continually separate MeOH from it's azeotrope with water, where 'dry' MeOH is led back to the reaction flask?
Patent DE628023 preparation of sodium methylate, using a refractionating column
Example
In a 500ml flask 40g NaOH and 200g MeOH are heated to boiling. The formed steam is dehydrated, for example in a fractionation column, and the low-water MeOH supplied back to the flask, until no more water distills. That way practically all the NaOH can be converted into the methylate. Excess MeOH is stripped off in the usual manner.
Patent DE519443 preparation of alkali metal alkoxides, using a column with dephlegmator(is that an english word ?)
Example 1
40 parts pulverized NaOH and 250 parts n-BuOH are heated in a still equipped with a column and dephlegmator. BuOH/H2O (azeotrope) are collected until the alcoholate formation is completed. The excess alcohol is then removed by distillation at normal or reduced pressure. 96g pure sodium butylate remain as foamy mass that is easily oxidised by air. Yield: 100%
This way alkali alcoholates of alcohols that form binary mixtures with water can generally be produced.
Patent US2451945 preparation of potassium methylate, using CaC2
Example 2
1.25 mols of calcium carbide, 1 mol of potassium carbonate and 19 mols of MeOH are heated to reflux for a few hours until all the calcium carbide has reacted. The slurry is filtered and the clear filtrate containing potassium methylate and methanol is subjected to distillation for removal of the methanol.
Patent DE505474 preparation of potassium ethylate, using gaseous alcohol
Example 1
Finely pulverized NaOH is suspended in high boiling paraffin oil (m=2,5 * m(NaOH)) and dry gaseous ethanol led thru the mixture, starting at the b.p. of the alcohol. EtOH with a H2O content of 0,4% distills. Keeping the EtOH in-stream constant, the temperature of the flask's contents as well as the EtOH vapor is raised to 200°C. The water content of the distillate immediately rises to 2,5%. After 10 times the amount by weight of EtOH relative to the amount of the NaOH has been led thru, the suspended reaction product is filtered. It consisted of a solid mixture of sodium ethylate and NaOH, the alcoholate being more than 50% of it. The small amounts of paraffin oil still adhering to the reaction products after the suction filtration not only no disadvantage but they even protect the product from air and humidity. Hexane and the other usual suspects remove the paraffin oil completely.
I think I've also seen an actual patent for the preparation of K/Na OEt/OMe where the water was removed as toluene-azeotrope using a dean-stark trap. Does anyone here know what I'm talking about ?
--psyloxy--
(Wonderful Personality)
06-09-04 01:59
No 512257
Post 511869 (Barium: "You can make the alkoxides by dissolving e.g.", Newbee Forum)
and followups.
in special:
Post 511982 (Organikum: "Process without distillation", Newbee Forum)
Post 512000 (gsus: "precipitation with acetone, alleged", Newbee Forum)
and prove of principle:
Post 512006 (Nicodem: "The patents work", Newbee Forum)
Nevertheless very good psyloxy, I like the "example 2" most as it answers the second of my questions asked here:
Post 511960 (Organikum: "Barium, do you know the composition and bp of...", Newbee Forum)
ORG
(Hive Addict)
06-09-04 06:33
No 512292
Yep, I've already read this when I checked TFSE to see whether I'd post anything redundant - still great to see it work, though. On the other hand, fluffy precipitate like Nicodem describes can look massive in solution, while it weights next to nothing, well you may all know this
--psyloxy--
(Hive Bee)
06-09-04 09:04
No 512323
the yield of whatever it is was high with the KOH/MeOH, even with the lost product that was too fine for the filters. didn't weigh the KOH flakes so i cant say how much. ended up cream colored. storage under the wash solvent should be fine for many applications-no need for the vacuum desiccator, though i dried it and felt the heaviness in the baggie. the problem is the amount of acetone, and the fineness. why not try it with a couple grams yourself?
http://www.archive.org/audio/etreelistin
(Hive Bee)
06-09-04 13:30
No 512372
Psyloxy: I didn't filtered and weighted the presumed NaOEt but I don't think it was in bad yield. 12ml of ethanol can hold utmost ~1.5g of NaOH so the there should bee produced ~2g of the sodium ethoxyde in my test. Judging by eye it was near that. The problem is only the amount of acetone needed (though it can bee recycled if one wants so).
BTW: Silicium carbide is an incredibly inert ceramic. It does not react with water.
“The real drug-problem is that we need more and better drugs.” – J. Ott
(Hive Addict)
06-09-04 19:01
No 512432
That's really encouraging news, would be the way to go then. I would feel like a thief if it was that easy, though
. Just think of the possibilities: CHCl3 + NaOMe __> HC(OMe)3 - 87% ; HC(OMe)3 + p-TsOH __> p-TsOMe - 99%
OTC methylating agent there you are. Details in Post 466982 (psyloxy: "practical alkyl tosylate synth - new approaches", Novel Discourse)
--psyloxy--
Summer of love, anyone ?
(acetaminophanatic)
06-11-04 05:21
No 512706
psyloxy, why not just use that trimethyl orthoformate to directly methylate the phenol again?
"...Now that's as close as a chemical, a drug, can get to being a good woman"
(Hive Addict)
06-11-04 06:53
No 512720
I've been feeding beilstein with phenol and HC(OMe)3, turned up 2 hits, that have nothing to do with alkylation. Would you know how that art is performed ?
--psyloxy--
(Hive Addict)
06-15-04 23:25
No 513638
Mol sieves! Here's the latest thoughts my brain generated on sodium methylate production:
Mix: 202ml MeOH, 40g NaOH, 100g mol sieves, stir for an appropriate amount of time with heating.Filter off the mol sieves. Theorethically you should be left with a 30% NaOMe solution in MeOH.
Now that I look at it, it's just like in Patent US2451945, only regenerate-able mol sieves are substituted for acetylene producing calcium carbide.
Suggestions ?
The ponderings that started it all are documented below for historical reasons:
Uhm, BTW: here's the $1 . 106 answer: methanol doesn't form an azeotrope with water. Here's the boiling-chart:
If we consider Patent DE628023 I think it can be taken for granted that the percentage of water in the vapor-phase is low because the equilibrium lies heavily on the left (little water is generated by NaOH + MeOH __> NaOMe + H2O) thus the difference in boiling points of MeOH and MeOH/H2O is small, a few °C if you're lucky. What big ass fractionation column did those crazy Germans think of ?
I think a much better approach would be to use a Soxhlet where you would be trying to extract the hell out of BaO/CaO or even better: mol sieves (3Å).
Dynamic drying: solvent is filtered thru a chromatography column. 250g mol sieves are sufficient to dry 10L of solvent to a water content of 0.002% (20ppm). Column: 2.5 x 60cm (~1"x23"). Throughput: 3L/h. (transl from : www-oc.chemie.uni-regensburg.de/OCP/meth
oden/kap 9.PDF )
Mol sieves have a capacity of ~20% their own weight, so you would need ~ 100g mol sieves for every 54g NaOMe.
Any objections ?
--psyloxy--
(Stoni's sexual toy)
06-16-04 18:37
No 513794
> Mix: 202ml MeOH, 40g NaOH, 100g mol sieves, stir for an appropriate amount
> of time with heating.Filter off the mol sieves. Theorethically you should
> be left with a 30% NaOMe solution in MeOH.
I doubt you can simply stir (or even filter) that mixture since it should have the consistency of wet concrete. Kneading and sieving would be more appropriate terms for those operations.
BUSH/CHENEY 2004! After all, it ain't my country!
www.american-buddha.com/addict.war.1.htm
(Hive Addict)
06-16-04 20:38
No 513809
it should have the consistency of wet concrete.
Because of the mol sieves or the NaOMe ? After all 30% NaOMe/MeOH is commonly referred to as 'solution' - that's what I took it for being.
However, using a Soxhlet, or more MeOH for that matter, should solve that problem.
--psyloxy--
(Hive Addict)
10-27-04 15:52
No 538187
The principle of KOH trapping water has been mentioned before in other patents found by you-know-who-you-are. Nonetheless I find this an extraordinarily beautiful example of the principle at work... so close to ultimate simplicity it fills my heart with joy. Have fun
Patent DE1043309
Example 2
In a procedure modeled after example 1 ethanol was used instead of 3-pentanol. The column was held at 68°C. The analysis of a sample taken from the top of the column showed 30.4% waterfree alcoholat.
Example 1
A glasscolumn of 25,40 mm diameter and 91 cm lenght is filled to one third with 8-mm glassrings and KOH (85%) in the form of pellets. 3-pentanol is filled into the column from the bottom with a speed of 5 mL / min. The column was kept at 120°C. A typical sample of what leaves the column from the top was analysed as 40% waterfree alcoholat and 2.5% dissolved KOH.
--psyloxy--