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Author: Subject: THF ( tetrahydrofuran)
neutrino
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I get the feeling that that last step would give you a cyclic polyether other than THF. The production of crown ethers goes along similar lines and yields a ring with a size approximately equal to that of the metal cation present (the template effect), and Na<sup>+</sup> is much too big to fit in a THF molecule. I’m not an expert in Ochem, but this just looks a little too similar for me.

Perhaps a solution of solvated electrons might get around this problem?

One more thing, this synthesis would probably have to be done in extreme dilution to prevent forming long chains and large rings. This is the same problem they had with crowns before the template effect was discovered.
BromicAcid
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I am fairly firmilar with crown ethers and it may well be possible for some 18-crown-6 to form in this reaction, however my attempts to form 18-crown-6 intentially from a similar reaction (involving potassium cations which have a stronger template effect in this case) resulted in a 0.015% yeild or something of that magnitude so I don't think I would get much of that. The Wurtz reaction has been used to create highly strained molecules via an intramolecular reaction so I don't think forming a 5 member ring would be taxing at all, though there is the need to preform the reaction under dillution as polyermization may be pronounced.

Never the less, this was not inteneded to be posted as a fesible reaciton, I have much better things to do with my bromine, phosphorus, and sodium together then use them all to produce a small amount of THF. Just opening up discussion on other methods to close this ring, although dioxane can be made from diethylene glycol somewhat readily THF is more useful in my opinion (or was that opinion grown from the fodness this forum has for THF, is there anything wrong with dioxane?)

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Illegal Parkinson
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EtOEt vs. THF

Forgive me for not reading the whole of this thread yet. My question is that why you dont just substitute the THF for EtOEt. I understand that THF has a higher boiling point so it is possible to reflux at higher temperature. Other than this though, are there any advatages to using THF?

Just editing to say I have read that THF is more polar than EtOEt and therefore better at solvating ions, particularly lithium salts and other organometallic compounds.

^To the poster above me, dioxane has a reputation as being significantly toxic (you probably alreeady know this since most solvents fit into this bracket). However finding a repalcement solvent for something like dioxane is the type of thing that might be deemed advisable.

[Edited on 19-10-2005 by Illegal Parkinson]
Venkat
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Stryer BIOCHEMISTRY

Thanks Ayush for the ebook!! And yeah, I'll probably read through the topic before posting next time... . But its just that my university notes have been referenced with pages from the STRYER book, which is why I am so anxious to get it. Has the Stryer EVER been posted in the forum?? If not, could anyone possibly post it?? Please!!! Thanks.

==Venkat==

P.S. Ayush, thanks for the rapidshare link. Yeah, its actually quite convenient for me to download from there... lol!!
BromicAcid
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Is the post above relevent? I think it was acidently posted here.

Anyway, been looking for a method to make 1,4-butanediol or 1,4-dibromobutane, or 1,4-dichlorobutane, or 1-bromo-4-hydroxybutane and found some methods to 1,4-butanediol along the way. Just searching through the abundant patents at the US patent office made from the 1970's to present day on ways to make THF I found that a majority of the methods require maleic anhydride but I figured that I could do better then that for a starting material. I found patents that described from the start the oxidation of butane with atmospheric oxygen in tubes to give maleic anhydride but that wasn't what I wanted either.

So far, the best I have found is the reaction between acetylene and formaldehyde in the aqueous phase to give 1,4-butynediol however this would still require a catalytic hydrogenation or the like. Never the less it doesn't sound like a bad procedure, it is described in a few patents such as US 4149004 and German patent 2421407 which is also avalible as the US patent 3957888 each calling for specially prepared copper catalysts.

Sounds pretty nifty though, I have a pound of calcium carbide and I'm sure I can round up some formaldehyde, as for the hydrogenation, US patent 4,588,827 references
 Quote: cf. German Laid-Open Application DOS No. 2536273
But I don't think its a patent, I can't find it on exp@cenet. One hydrogenation procedure that I did find that did not use palladium or platinum was in US patent 3950441
 Quote: An improved hydrogenation catalyst is provided comprising a high surface area amorphous or gamma alumina support carrying thereon from about 12 to about 20% by weight of nickel, about 1 to about 10% by weight of copper and from 0 to about 1.5% by weight of manganese. This catalyst is used as a second stage catalyst in the two stage hydrogenation of 1,4-butynediol to 1,4-butanediol. This is a division of application Serial No. 72,870 filed Sept. 16, 1970 now U.S. Pat. No. 3,759,845
Anyway, back to work.

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BromicAcid
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Again thinking about THF from diethylene glycol. Recently I've had the pleasure of looking over two interesting books posted in the "New books thread" Electro Chemistry of Organic Compounds posted by chochu3 and Organic Electrochemistry posted by CherrieBaby, now, previously I thought that a Kolbe electrolysis type reaction was fairly crummy and somehow I got the impression that yields in such a reaction were in the range of ~10%, but after reading though some of these texts I've found that under great conditions with a good carboxylic acid one can get yields approaching 90%, and more realistically 50%, now those don't seem that bad for a dimerization.

So, how about oxidizing dipropylene glycol to the diacid then subjecting it to electrolysis to attempt to couple the ends and make the cyclic THF? Not really realistic, according to the household products database only one avalible item has significant dipropylene glycol (<80%) but it also contains many fragrances and such so probably wouldn't be suitible. Still, it's a thought. Btw, what would the diacid of dipropylene glycol be named?

HOOCCH2CH2OCH2CH2COOH

Although the prominate reaction will likely be polymer formation.

[Edited on 12/8/2005 by BromicAcid]

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BromicAcid
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Once again, more methods to THF, though these ones are not too bad. They all start from the somewhat availible 1-butanol and involve the use of one somewhat exotic oxidizing agent or or another. I don't remember what book I was reading through but I ran across a chapter on a specific reaction mechanism relating to this thread reffered to as: (5)OC-cyclo-Alkoxy-de-hydro-substitution, the simple case being:

CH<sub>2</sub><b>H</b>CH<sub>2</sub>CH<sub>2</sub>CH<sub>2</sub>OH ---[Pb(OAc)<sub>4</sub>]--> THF
 Quote: Alcohols with a hydrogen in the δ position can be cyclized with lead tetraacetate.196 The reaction is usually carried out at about 80C (most often refluxing in benzene) but can also be done at room temperature if the reaction mixture is irradiated with uv light. Tetrahydrofurans are formed in high yields. Little or no four- and six-membered cyclic ethers (oxetanes and tetrahydropyrans, respectively) are obtained even when γ and ε hydrogens are present. The reaction has also been carried out with a mixture of halogen (Br2 or I2 and a salt or oxide of silver or mercury (especially HgO or AgOAc),197 with iodobenzene diacetate and I2,198 and with ceric ammonium nitrate (CAN).199 196 For reviews, see Mihailovic; Partch Sel. Org. Transform. 1972, 2, 97-182; Milhailovic; Cekovic Synthesis 1970, 209-224. For a review of the chemistry of lead tetraacetate, see Butler, in Pizey, Ref. 85 vol. 3, 1977, pp. 277-419. 197 Akhtar; Barton J. Am. Chem. Soc. 1964, 86, 1528; Sneen; Matheny J. Am. Chem. Soc. 1964, 86, 3905, 5503; Roscher; Shafferr Tetrahedron 1984, 40, 2643. For a review, see Kalvoda; Heusler Synthesis 1971, 501-526. For a list of references, see Ref. 74, p. 445. 198 Concepcion; Francisco; Hernandez; Salazar; Suarez Tetrahedron Lett. 1984, 25, 1953; Furuta; Nagata; Yamamoto Tetrahedron Lett. 1988, 29, 2215. 199 See, for example, Tranovsky; Young; Nave Tetrahedron Lett. 1969, 2501; Doyle; Zuidema; Bade J. Org. Chem. 1975, 40, 1454.
Despite the lack of ready avaliblity of the oxidizing agents necessary for the conversion, it is still interesting to consider the transformation, note that reactions such as the one utilizing bromine with silver oxide supposedly take place through a hypobromite attaching to the side opposite of the alcohol and completing the ring closing followed by the silver atom coming along and plucking off the bromine and removing it. I have most of the references readily availible so I will take the time to look through them later, but for now they are interesting side notes to go from 1-butanol to THF.

[Edited on 12/10/2005 by BromicAcid]

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runlabrun
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Even if the yields are low to buy several liters of 1-butanol is cheap so it really wouldnt matter to much. Whats the catch?

-rlr
BromicAcid
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Yields are not low, acutally they are described as high for the lead tetraacetate process, the catch is the choice of oxidizing reagents:

Pb(OAc)<sub>4</sub> - Your choice of $.75 a gram (if you can find a supplier willing to sell it to you) or glacial acetic acid/acetic anhydride, or glacial acetic acid + chlorine gas. It's not a catalytic process so lead tetraacetate is consumed, the more THF you want, the more Pb(OAc)<sub>4</sub> you need. Br<sub>2</sub> or I<sub>2</sub> with AgOAc - Again silver is not catatalytic, it could be recovered, but any reaction using silver and a halogen simultaneously is just too expensive. Br<sub>2</sub> or I<sub>2</sub> with HgO - Mercury salts now? Toxic and expensive. Ceric Ammonium Nitrate - Somewhat expensive and difficult to make. Personally I think lead tetraacetate would be the best for this process as it is somewhat easily made providing you have glacial acetic acid, with electrolysis or chlorine is is possible to make lead tetraacetate without acetic anhydride. Also the reaction yields lead (II) acetate, and acetic acid, recovery should be feasible and using electrolysis lead (II) acetate can be converted back to the tetraacetate. One interesting side note, as I mentioned in my post, it is believed the intermediate agent in the reactions involving the free halogens is a hypohalide ester, this is decomposed by the silver or mercury to give the desired product. In a different thread I reported on finding that butyl hypochlorite can be decomposed to give 1-chloro-4-butanol which could be converted to THF  Quote: Is butanol restricted or watched in any way? I found a method to THF via butanol today but it is quite the pain in the butt, involving first converting the butanol to the hypochlorite ester and allowing that to decompose in the presence of sodium bicarbonate with benzene under reflux for an hour. You end up with ClCH2CH2CH2CH2OH in a 17% yield which can then be reacted with aqueous NaOH or KOH to give THF which can then be distilled off, as the author of the article did. I wonder if there is some other way then mercury or siver to afford this conversion in one step with better yields then the hypochlorite process. Shamelessly plugging my attempts at writing fiction: http://www.robvincent.org Magpie lab constructor Posts: 5939 Registered: 1-11-2003 Location: USA Member Is Offline Mood: Chemistry: the subtle science. I have just isolated some THF via fractional distillation of a PVC pipe primer. I am now concerned about how to store it safely. Organikum says that ether peroxide generation can be prevented by adding copper to the storage container. I have done this in the form of cut-up copper wire. Lyondell, who sells THF in industrial quantities, adds a minimum of 200ppm BHT. Per their MSDS, BHT, as an anti-oxidant, stabilizes THF by preventing the formation of peroxides and polymers. So, should I be making a trip to the health food store to obtain some pure BHT powder for my THF? Any advice will be appreciated. The single most important condition for a successful synthesis is good mixing - Nicodem Fleaker International Hazard Posts: 1246 Registered: 19-6-2005 Member Is Offline Mood: nucleophilic I have heard about the copper wire trick, but I'm not sure if it works or not, and I'm far too tired to think on it. I would suggest getting some BHT for your THF, and keeping it in the freezer to slow the kinetics. Better safe than sorry. Diethyl ether can be stored in the freezer safely for quite some time if it is capped tightly. Magpie lab constructor Posts: 5939 Registered: 1-11-2003 Location: USA Member Is Offline Mood: Chemistry: the subtle science. Fleaker, I'm not sure it works either, at least with THF. I just tested my THF for peroxides using acidic 10% aqueous KI. The result was distinctly positive. I can't find any BHT locally but can order it over the internet. Thanks for the tip about putting it in the freezer. I could always get rid of it but hate to as I put a lot of work into getting it. I have about 80mL. The single most important condition for a successful synthesis is good mixing - Nicodem Magpie lab constructor Posts: 5939 Registered: 1-11-2003 Location: USA Member Is Offline Mood: Chemistry: the subtle science. Here's a picture showing the results of the test for peroxides. The left test tube is the control with just 1.5mL of acidic KI, the middle test tube has 0.5mL THF added, and the right tube has one drop of 3% H2O2 added. EbC: Picture size! [Edited on 26-1-2007 by chemoleo] The single most important condition for a successful synthesis is good mixing - Nicodem Magpie lab constructor Posts: 5939 Registered: 1-11-2003 Location: USA Member Is Offline Mood: Chemistry: the subtle science. My THF has been sitting in my freezer for about 7 weeks now with the 1000 ppm BHT added. I tested it today for peroxides with fresh KI. The test was negative. The single most important condition for a successful synthesis is good mixing - Nicodem EtherBunny Harmless Posts: 11 Registered: 2-2-2004 Member Is Offline Mood: adrenergic This is probably a little off-topic. I love THF. We have gallons and gallons of it in our lab, and it's especially nice as a "universal solvent." Working with large substituted polycyclic hydrocarbons, we often run into some real solubility problems; THF will dissolve almost anything, and is much safer to use than another dissolve-all like HMPA, which is a nasty carcinogen. I think that one of the reasons that THF might be regulated as it is is simply because it's derived from the hydrogenation of furan, which, based on what I've heard, is an extremely nasty compound. As for a way to make it, it could hypothetically be made from dehydrating/hydrogenating furanose sugars... Palladium and high heat might do it. Magpie lab constructor Posts: 5939 Registered: 1-11-2003 Location: USA Member Is Offline Mood: Chemistry: the subtle science. I like what you are saying EtherBunny. I would rather be using THF than diethyl ether as long as it is an equivalent solvent. Do you happen to know if it is suitable for Grignard reactions? As far as obtaining THF OTC the distillation from PVC pipe primer is not too tough. However, I have not tried recovering diethyl ether from starting fluid so can't make that comparison. Making it from alcohol is not that great IMO. The single most important condition for a successful synthesis is good mixing - Nicodem The_Davster A pnictogen Posts: 2861 Registered: 18-11-2003 Member Is Offline Mood: . Yeah, it works for grignards(firsthand experiance in org lab). EtherBunny Harmless Posts: 11 Registered: 2-2-2004 Member Is Offline Mood: adrenergic Magpie- Yeah, you probably can use it for Grignards, just make sure it is completely anhydrous. My big problem with THF is its miscibility with water, which makes using it for an extraction solvent impossible. Chris The Great National Hazard Posts: 463 Registered: 29-10-2004 Location: Canada Member Is Offline Mood: No Mood Distilling from starting fluid is ok but you end up using a lot of water to cool it effectively. THF and ether can't be always used instead of one another, in some cases the fact THF is polar and Ether not will make a difference. I believe this was recently discussed in a thread about the reaction of benzylmagnesium chloride and acetonitrile IIRC, where using THF basically ruined the reaction. jimwig Hazard to Others Posts: 215 Registered: 17-5-2003 Location: the sunny south Member Is Offline Mood: No Mood if i remember correctly --- hahahahahahaha the quote was for one bag. it costs almost as much to ship it as to buy it. i might be wrong about all this......hahahaha [Edited on 12-4-2008 by jimwig] craZy jiM wGGns --packrat, professional bum. -- once just tired now REtired. Sauron International Hazard Posts: 5351 Registered: 22-12-2006 Location: Barad-Dur, Mordor Member Is Offline Mood: metastable Furfural (furfuraldehyde) is easy to make and easy to buy. To prepar furan from it, you first oxidize fufural to furoic acid and then decarboxylate that. Furan is extremely volatile. There are two good procedures for the oxidation, both in Org.Syn. One is a Cannizarro reaction giving furoic acid and furfuryl alcohol. The other is an oxidation with copper oxide and silver oxide under O2. Sic gorgeamus a los subjectatus nunc. LSD25 Hazard to Others Posts: 239 Registered: 29-11-2007 Member Is Offline Mood: Psychotic (Who said that? I know you're there...) Just found this, it is a paper from Natal where the author's use steam (@20Atm) and phosphoric acid to get furfural from sunflower husks. It is a very interesting read and providing you know how to pressure-weld, probably something that you could do at home on a smaller scale (IIRC about 9.7% yield on dry weight). Bagasse, etc. can also be used, although could one start from purified pentoses? H3PO4 is a lot better for me than H2SO4, simply on availability grounds, so if this could be done with xylose, etc. it would be an interesting reaction to attempt. Here is the paper: http://www.ift.co.za/media/archive/SAIChE%20Congress%202003%... Furfural can apparently be oxidised to furanoic acid and decarboxylated by heating it to around 250C in acidic environments (I read this somewhere). Whhhoooppps, that sure didn't work MagicJigPipe International Hazard Posts: 1554 Registered: 19-9-2007 Location: USA Member Is Offline Mood: Suspicious I was thinking about distilling THF from a product called X-15 Shower Tile Adhesive. The only two ingredients listed on the MSDS are THF (35-50%) and polyester resin. I am assuming the polyester resin is WAY less volatile than THF and shouldn't pose a problem. My concern is the hazards associated with distilling any ethers. Surely the product is "stabilized". But with what, out of curiosity? At 35% the amount of THF per$6 can is about 250mL. That rivals the prices of THF bought by the liter from a chemical supplier.

I am thinking about distilling it straight from the can so I won't "ruin" my flasks. Would ketones, esters or alcohols be good at dissolving the polyester resin? Does it polymerize after the THF has evaporated (I'm almost certain it does, otherwise how would it be an effective adhesive?)

Does anyone have experience with this? Does placing the mixture in water help get rid of the resin?

So many questions, such little time...

"There must be no barriers to freedom of inquiry ... There is no place for dogma in science. The scientist is free, and must be free to ask any question, to doubt any assertion, to seek for any evidence, to correct any errors. ... We know that the only way to avoid error is to detect it and that the only way to detect it is to be free to inquire. And we know that as long as men are free to ask what they must, free to say what they think, free to think what they will, freedom can never be lost, and science can never regress." -J. Robert Oppenheimer
Panache
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i find distilling from the can it came in is always the most convenient for glues and paint strippers. It doesn't mean you'll get a decent fractionation or anything but you have something which you can conveniently use in your glassware to further resolve.

As a general rule remove 1/3 of the can contents, spike a hose from the can to your condenser, immerse can in water and heat water electrically. Very sophisticated, when sufficient distillation has occurred pour in remaining 1/3 of starting material and distill to completion.
Throw away can responsibly (or burn it!!)

halogen
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 Quote: Originally posted by PainKilla ... This [furfural] can be converted to THF by further heating in presence of acid.

Is this true? What are the conditions of this?

F. de Lalande and M. Prud'homme showed that a mixture of boric oxide and sodium chloride is decomposed in a stream of dry air or oxygen at a red heat with the evolution of chlorine.
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 Sciencemadness Discussion Board » Fundamentals » Miscellaneous » THF ( tetrahydrofuran) Select A Forum Fundamentals   » Chemistry in General   » Organic Chemistry   » Reagents and Apparatus Acquisition   » Beginnings   » Responsible Practices   » Miscellaneous   » The Wiki Special topics   » Technochemistry   » Energetic Materials   » Biochemistry   » Radiochemistry   » Computational Models and Techniques   » Prepublication Non-chemistry   » Forum Matters   » Legal and Societal Issues