Sciencemadness Discussion Board

THF ( tetrahydrofuran)

atombum - 15-8-2004 at 14:40

As tetrahydrofuran seems to be rapidly turning into a hard-to-find solvent, I became curious of who offered it and at what price. Every supplier had a bit of info on it that became one of those questions that bugs the hell out of you and yet you discover is almost impossible to find an answer to via search engines-
Why in the world is there a hazmat charge placed on every amount of it? Flammability? No, ether (even isopropyl!!), and probably any similiar bp alkanes, can be sent under limited qty. exemption. Toxicity? That's a no brainer. Peroxidation? Well again consider the ethers, plus THF is usually inhibited.
Does anyone know why this would be done?

[Edited on 23-11-2004 by chemoleo]

JohnWW - 15-8-2004 at 15:19

Tetrahydrofuran, cyclo-(CH2)4O, a cyclic ether (like furan, furfural, pyran, oxetane, dioxane), obtained by hydrogenation of furan (obtained by reduction of furfural, itself obtained by the acidic dehydration and hydrolysis of cellulose containing materials like bran), is supposed to be a common solvent in industrial and laboratory synthetic organic chemistry, e.g. for organolithium and organomagnesium compounds. It is also used, in its adduct product with BH3 by reaction with B2H6, to obtain organoboron compounds

It has a of -108ºC and a of 65.4ºC, which makes it useful for hosting very low-temperature reactions.

It is also slightly more volatile than the lowest non-cyclic ethers. There does not seem to be any particular chemical reason why it should be regarded as more hazardous than these other light ethers like diethyl ether. Perhaps the answer is that it is a good solvent for the production of certain illegal drugs or explosives.

John W.

DDTea - 15-8-2004 at 15:40

From comparing the MSDS's of THF and Diethyl Ether, I've found one difference... THF will form hazardous polymers while Diethyl Ether will not. I don't know if that warrants the Hazmat charges though.

I don't think the charges are related to its illegal uses though; it would make more sense to scrutinize the buyer more heavily than to simply make him pay a little extra.


MadHatter - 15-8-2004 at 16:12

IIRC, TetraHydroFuran is a substance used in the manufacture of
many synthetic drugs. LSD comes to mind. I can't say for sure, but this
1 is probably on the DEA's watched list. If it is, BE CAREFUL if you order it !

atombum - 15-8-2004 at 20:14

In response to MadHatter- Like an increasing number of compounds, it's probably on the high-priority end of that list.
And in regards to what Samosa stated, I agree that the illicit material manufacture aspect of the chemical is probably not relevent to transit. The more heavily(or at least similarly) watched, and more flammable diethyl ether is not hazmat.
I also tend to agree that it may very well be the polymerization aspect that was mentioned. The MSDSs do tend to indicate a greater instability than aliphatic ethers. And, this would probably be aggrevated to a more severe degree when uninhibited.

Marvin - 15-8-2004 at 20:36

JohnWW, furan obtained by the reduction of furfural? Interesting, whence goes the offending carbon?

Wild guess but cyclic ether of 4 carbon atoms to me suggests people are making GHB from it.

Darkfire - 15-8-2004 at 20:45

Thats an intresting idea THF to GBL is a known synth, but that still shouldnt affect the price of shipping.

Marvin - 15-8-2004 at 21:23

GBL to GHB is a pretty trivial process, so for me that clinches it, it probably is being abused that way and this may well be why its getting hard to find.

Hazmat charges may be at the discression of the supplier, I didnt find much in the way of enforced classification. On the other hand the following from 'Hazmat magazine" might tip the balence somewhat.

"Carcinogenicity -- The International Agency for Research on Cancer (IARC) has not evaluated THF for its carcinogenic potential. Inhalation studies in rats have produced inconsistent results, in that liver and/or kidney tumours were observed in some studies but not in others. However, clear evidence of carcinogenicity has been observed in inhalation studies with mice."

Its ether like, fairly low toxicity and carcinogenic.

Democritus of Abdera - 15-8-2004 at 21:48

Originally posted by Marvin
GBL to GHB is a pretty trivial process, so for me that clinches it, it probably is being abused that way and this may well be why its getting hard to find.

Hazmat charges may be at the discression of the supplier,

All shipping charges are at the discretion of the supplier.

With anyand every precursor in demand, there will be those who will stop selling it to the public out of morality or concern about liability in this litigous world, and there will be those that seek to profit from the distribution of it, they are called opportunists.

"Hazmat fees", Handling charges....packaging fees...are just another way of adding to the cost of a substance, in a roundabout way, so that you won't notice the real price until the checkout line.

Sort of like the way some companies give 100% MONEY BACK GUARANTEE!!! TRY FOR THIRTY DAYS WITH ABSOLUTELY NO RISK!!! and then charge you a 30% "restocking fee" if you do send it back.

I think most of us have had the experience of getting suckered into a "great buy" on ebay or LabX only to discover the ridiculous S+H fees that boost the product to near normal market values.....those bastards!....they killed my naivete!

JohnWW - 15-8-2004 at 21:54

Just off the top of my head, I think furan, cyclo-(CH)4O, which has aromatic resonance structures involving a positive charge on the O, can be obtained from furfural, C4H3O-CHO, by heating with red phosphorus, which removes the -CHO (which is on the 1-carbon). Furfural is obtained by heating cellulose substances with H2SO4, the concentration of which has to be carefully controlled to avoid dehydration to carbon. However, surprisingly few organic chemistry textbooks seem to have anything about the preparation of furan or furfural, or the removal of -CHO groups from aldehydes.

John W.

Marvin - 16-8-2004 at 00:43

I went over furfural reasonably well (I thought) in a thread on roguesci. Its not the cellulose thats important, its hemicellulose which breaks down into sugars that are largly pentoses and those are what dehydrate into furfural. Bran is good, corncobs are good, I have some methods from mid 19th century but the one on orgsyn from 1940's or so is better.

The only methods I know of making furan from furfural though are the brute force industrial method, decarbonylation with palladium/carbon, and the obvious method of oxidise to the acid and decarboxylate. This turns out to be fairly easy by just heating the acid to boiling point (Organic synthesis). Orgsyn also mentions in passing furfural + sodalime, or fused sodium/potassium hydroxide, I wonder if this includes oxidation or is just canizzaro based. Nothing about Red P or removal by reduction.

I dont see how heating with Red P would work, as it is the carbon has to come off as monoxide, any reduction would leave the carbon in a lower oxidation state! Do you have a reference for this method?

Democritus, there is a big difference between the supplier enforcing hazmat packaging and the goverment. I have noticed a lot of places enforcing hazmat on items only when shipping within the US. This seems to be to keep to legal requirements.

David Marx - 16-8-2004 at 04:12

I have actually been hunting for this solvent for a while. Does anyone know of an OTC source for THF. I don't need much, around 250 mL should do.

Polverone - 16-8-2004 at 10:03

It's a significant component of various PVC glues and primers, but always mixed with a variety of other chemicals; methyl ethyl ketone and cyclohexanone were most common from the few MSDS sheets I glanced at, sometimes acetone too. You'd be lucky to find a formulation with more than 25% THF in it. I don't know of any way to isolate it in high purity, but that could be a starting point if you wanted to come up with a method yourself.

CommonScientist - 20-8-2004 at 11:28

I see 50,000 gallon rail cars filled with THF all the time, going west usually. Some friends of mine who live on a farm close to railroad tracks have gotten some items from there when a train stops occasionnaly, like a pallat of toilet paper, etc. If you could find the drain on one of those tankers, you could fill up an auxillary fuel tank in the back of a pickup rather fast with it. :o:D

Bah, Im rambleing again.

JohnWW - 20-8-2004 at 13:11

You see a lot of THF on rail tanker cars "going west"? (literally as well as figuratively). Perhaps you could make some inquiries as to the destination where those tanker cars are unloaded, and approach the recipient to obtain a small quantity.

John W.

axehandle - 21-8-2004 at 05:19

Does anyone know whether THF is conductive? If it's not, its very low MP might just make it suitable to use as a replacement for expensive Fluorinert for use as a coolant fluid in experimental computer overclocking together with liquid N2... but perhaps I'm dreaming.

And it might just dissolve the PCB components...

JohnWW - 21-8-2004 at 13:19

The only problem with such a proposed use of THF as a coolant, in place of a fluorocarbon, is its inflammability. Its flash point in air mixtures would not be very high.


unionised - 27-8-2004 at 13:19

It's also an excellent solvent, particularly for PVC.
What are the wires insulated with?
(flash point is about 20 below zero)

BTW THF is not more volatile than the lowest ethers; dimethyl ether is a gas.
(Edit; just checked, methoxy ethane (Bpt 7C) is too.)

[Edited on 27-8-2004 by unionised]

thefips - 31-8-2004 at 09:53

Is THF really a substance which is used to make a lot of drugs?GBL comes to my mind,but I can´t think of more substances. I hope it is allowed to talk about the drugs,which require THF as a starting material,because no instructions for the synthesis are said.But now I´m interesed.I knew that it can be used for GBL,but the synthesis is shit,if the wrong catalyst is used.I tried it three times,but the reaction got out of control and a brown liquid was spilled all over my garage and my lab,because it begun suddenly to boil very vigorous.Because of this I think it would be better to obtain GBL fron someone who has access,for example it is used as an industrial solvent and some people sell it here in Germany.

neutrino - 31-8-2004 at 10:31

You want the HIVE. I think we can discuss stuff as long as it is theoretical, and not practical. As far as the DEA is concerned, as long as the chemical is used in any stage of the production of any common drug, it will be put on one of the lists of watched substances. HCl,H<sub>2</sub>SO<sub>4</sub> KMnO<sub>4</sub>, you name it.

Polverone - 31-8-2004 at 11:19

The emphasis on theoretical-not-practical is reserved for energetic materials. Anyone can ask any question here that they please; the trick to not be told "look elsewhere" is to phrase the question in a suitably high-minded way.

Example of the wrong way:
"How do I make meth?"

Example of the right way:
"What is the simplest way to prepare benzyl cyanide starting from toluene?"

The second question is far more specific, shows that the poster has already done some homework and now wants help with specifics rather than generalities, and is a perfectly acceptable home-chemistry challenge regardless of how the benzyl cyanide will be used once produced.

Some questions on substances of a "controversial" nature might be best-asked elsewhere, but will never be driven away from this site if asked in an appropriate manner. This is a site for chemistry more so than cookbook-recipes.

true_alchemy - 30-9-2004 at 10:22

THF is available in drums from about half of the general industrial chemical supply houses. Liondell is the main manufacturer and they probably have a hundred distributors in the US. Drum prices are usually 1.00 to 2.00/#.

neutrino - 30-9-2004 at 13:27

I think we're looking for a source that isn't going to make the DEA pay us a little visit.

garage chemist - 22-11-2004 at 14:26

Now I also got interested in furane chemistry and I want to learn more and prepare furfural from hemicellulose.
I heard that peanut shells can be used as a starting material, so I'm going to use that.
They are first boiled with 5% H2SO4 at a pressure of 4 bar (can be done in a kitchen pressure cooker), this converts the pentosanes into pentoses (sugars with 5 C- atoms). These are then somehow converted into furfural, probably by heating with stronger H2SO4. Seems like a lengthy process.
Döbereiner first made furfural by distillation of "Kleie" (don't know the english word for it, it's just another hemicellulose containing material, I'm going to use peanut shells) with dilute H2SO4, so the pressure cooking seems to be unnecessary.
The most important question: What is the required concentration of the H2SO4, and how much peanut shells should be used per 100ml of H2SO4?

When I have the furfural, I also want to make furan. The decarboxylation of 2-furanecarbonic acid seems to be the easiest way. Any ideas on how to oxidise the furfural to 2-furanecarbonic acid?

These syntheses all seem very interesting- making something as exotic as furfural and furane and maybe even THF from organic waste material. Furane chemistry is going to be one of my new projects.

[Edited on 22-11-2004 by garage chemist]

jimwig - 22-11-2004 at 18:16


garage chemist - 23-11-2004 at 00:04

Great Synthesis! Thanks a lot.

Why do they use H2SO4 and salt? It seems like HCl can be used, too (this is easier and cheaper). Or is the H2SO4 also important to the process? They said that the HCl was the important factor.

Marvin - 23-11-2004 at 04:19

Difficult to say, but it is unwise to modify a tried and tested method.

For the oxidation, if you follow the links from the page jimwig pointed to, you'll find a method using oxygen catalysed by copper oxide/silver oxide under the heading 2-furoic acid, only a small amount of silver nitrate is needed and the yeild looks high. There is also a description of the prep of furan from this.

[Edited on 23-11-2004 by Marvin]

Theoretic - 23-11-2004 at 06:42

The stuff (THF) is bad for your body.

garage chemist - 23-11-2004 at 11:02

Originally posted by Marvin
For the oxidation, if you follow the links from the page jimwig pointed to, you'll find a method using oxygen catalysed by copper oxide/silver oxide under the heading 2-furoic acid, only a small amount of silver nitrate is needed and the yeild looks high. There is also a description of the prep of furan from this.

Ok, thanks for this, now I know everything I need.
Sorry for not searching the site :( I could have found that out myself.

When my thermometer + ground glass adapter finally arrive and I have enough time, I will try out the furfural synthesis (on a small scale, 20 ml 10% H2SO4, 20g salt, 15g dried peanut shells- this should give 1,8 - 2,2 ml of furfural) . I'll report my results here.
I will use peanut shells instead of corn cobs first, only if this doesn't work I will get some corn cobs.
Does anyone know if empty corn cobs should be used or cobs with the kernels still in place?

@ Theoretic: THF is not very toxic, it's used in OTC solvent mixes. Furfural and especially furan are much more dangerous.

[Edited on 23-11-2004 by garage chemist]

Ref: THF Synthesis

solo - 23-11-2004 at 23:20


Keigo Fugami , Koichiro OshimaX, and Kiitiro Utimoto
Tetrahedron Letters,Vol.28,No.7,pp 809-812,1987

Treatment of a mixture of allylic alcohol and vinyl ether in thepresence of Pd(OAc)2 provides 2-alkoxy-4-alkenyltetrahydrofuran in good yield.

[Edited on 24-11-2004 by solo]

Attachment: TL 1987,28,809.pdf (229kB)
This file has been downloaded 1181 times


mick - 25-11-2004 at 13:18

THF is an good solvent for a lot of reactions.
Organometallic reactions work well in dry THF, more polar than ether so it dissolves more stuff. It is very good for organolithium reactions because the lithium needs to be highly solvated under anhydrous conditions. With ether, under anhydrous conditions, most things are so insoluble because they are not solvated that nothing much happens.
Another good thing about THF is that it is miscible with water but easily salted out.
THF will also soften most plastics (except PTFE, to date) over time.

THF in Pipe Glue

cyclonite4 - 30-11-2004 at 04:07

Originally posted by mick
THF will also soften most plastics...

Yeah, I think this is why it is used in PVC pipe glues, to soften the surface of the pipe to allow the adhesive to bond better.

@Polverone: Ive found glues with higher than 25% THF, infact i was just gluing pipes for a spudgun when i saw the back of the container (next to the flammability warnings) saying "ADHESIVE contains Flammable Liquids

30-60% Tetrahydrofuran 30-60% Cyclohexanone"

This means a minimum of 30%, upto 60% (unlikely though) THF.
I can get this pipe glue in large amounts relatively cheap (for me anyway), all i need is a way of isolating the THF.:cool:

Darkfire - 13-12-2004 at 22:06

Lo Voc has 50%-70% THF.

If its just resin, THF, and cylcohexanone distilation should work well.

[Edited on 14-12-2004 by Darkfire]

cyclonite4 - 18-12-2004 at 05:43

I know i can distill the THF and cyclohexanone out of the resin, but how difficult will the seperation of the two be, i cant find any data in my books here on boiling points.

Just a curious question: I left some pipe glue on a piece of pipe for a few minutes and then tried to scrape it off. A large piece of the PVC came off and it was very soft. Is THF the one responsible for the softening of the pipe?

Darkfire - 18-12-2004 at 13:06

This is what you do, i just tryed this 2 minutes before typing this so it works. Take the pipe cement and dump it in a beaker water with about 3/4 the volume of the cement. Then take a stir rod and mix well, the resin with form a ball around ur stick, keep mixing until ur sure the water has disolved all of the THF and the resin is no longer liquidy but a soilid ball. Now filter the resin from the mix, and squeze even drop out of the resin ball. Dump in a bit more than enough salt to saturate the water and poof organic layer floats to the top, use a sep funnel or just a plastic bag to seperate the two layers. Theres your THF and any other solvents in the can. Thats as far as i got. Now to get rid of the rest add this to some water and add in some sulfite to kill the peroxides and get rid of the ketones and seperate again. Then you have your THF.

cyclonite4 - 18-12-2004 at 22:01


Cyclohexanone is a ketone, so the sulfite should kill it. But by kill, what do you mean, what new compound(s) would form?

Darkfire - 19-12-2004 at 10:41

I think it complexes to it and will sink into the water layer.

corn cops 'er cobs

jimwig - 20-12-2004 at 07:08

i found corn cobs for about $12 / 50# online. try abrasive suppliers - industrial wholesale.

JohnWW - 20-12-2004 at 20:21

I undferstand that THF can be made by the acid hydrolysis, usually with dilute sulfuric acid, followed by distillation, of the particular type of cellulose found in corn cobs. The initial product is furfural, C4H3OCHO, from which the -CHO is removed to produce furan, C4H4O, which is then hydrogenated to THF, C4H8O.

Wood and sugar and some other carbohydrate materials can also be used.

Marvin - 22-12-2004 at 10:09

John, what do you think half the posts in this thread are about?

Wood cannot be used, ordinary sugars cannot be used.


What are the units to that price?

JohnWW - 23-12-2004 at 01:52

I am not sure exactly what they do, but I have seen a reference to wood and sugar being used to make furfural. The process would have to be somewhat different from that using corn-cobs.

PainKilla - 9-2-2005 at 05:30

How interesting, xylitol is a direct derative of xylose, which is a precursor to furfural. Furfural is simply made by heating xylose under acidic conditions. This can be converted to THF by further heating in presence of acid.

Would it be possible to somehow reduce xylitol into xylose? This would be quite an easy synthesis of THF, as xylitol is about 10$ per 5 pounds, and this would make A LOT of THF... I am not sure however whether the strucutre of xylitol is actually a pentose ring or a straight structure. If it is a ring, then someone could perhaps figure out a way towards THF synthesis?

frogfot - 9-2-2005 at 08:57

Is there an OTC source for pentoses? That acid catalysed preparation of furfural would probably work with any pentose, cyclic or not..
One would sure benifit from using starting material of higher sugar content..

Btw, I've always wondered, in OrgSyn page where they're using corn cobs, do they take cobs in dry weight?

Esplosivo - 9-2-2005 at 09:22

Yes frogfot, '... 1.5kg of dry corn cobs...'. Therefore I think they do intend the dry weight.

Surely where I live no pentoses are available OTC. I might buy them from a chem supplier buy they are quite expensive for small quantities (as small as 25g of ribose). Hope this helps.

Edit: May I ask what's wrong with using xylitol, it is a pentose and is available OTC (used in diets since it contains a third less calories than other sweetners if I remeber correctly). I don't think it would be too difficult to obtain. If a chem supplier is the only option I doubt many questions will be asked regarding its use.

And btw, the cyclic and linear isomers of sugars, such as pentoses (eg xylitol) are in equilibrium with each other such that all will be present. In solution the cyclic structure will predominate, I'm not sure in the solid state though. (The cyclic sugar may also possess isomers of the beta- and alpha- type, but thats just an extra detail...)

[Edited on 9-2-2005 by Esplosivo]

PainKilla - 9-2-2005 at 12:24

Was my post totally disregarded? I just mentioned that xylitol is cheap and easily avaialbe from many sources. Xylose is it's parent sugar and the direct precursor to furfural which is easy to make into THF. I am a bit... um.. not clear of mind now so Ill finish this later.

frogfot - 9-2-2005 at 12:52


'... 1.5kg of dry corn cobs...'. Therefore I think they do intend the dry weight.

Oh, damn sorry.. I have actually read the translated version of that text (in Russian) and they didn't mention this (maby this was concidered obvious.. I dunno) I never bothered to reread the original text..

PainKilla, that's useful info but I meant pentoses other than xylitol. I did a quick search on google and didn't find any local sources.. well maby I should search harder.. [rolleyes].. :P


Eclectic - 9-2-2005 at 14:16

Carbon Efficiency and the Surface Chemistry of the Actinides: Direct Formation of Furan from Acetylene over -UO3

Authors: Madhavaram H.; Idriss H.

Source: Journal of Catalysis, February 2002, vol. 206, no. 1, pp. 155-158(4)

Publisher: Academic Press


This work presents the direct oxidative coupling of two molecules of acetylene to furan (C4H4O) over the surface of pure polycrystalline -UO3. For comparison, only traces of furan are formed over -U3O8 and none on UO2 surfaces. A comparison to the reactions of other C2 compounds (ethanol (H. Madhavaram and H. Idriss, J. Catal. 184, 553 (1999)), acetaldehyde (H. Madhavaram and H. Idriss, Catal. Today 63, 309 (2000)), and ethylene (H. Madhavaram and H. Idriss, J. Catal. 184, 553 (1999); H. Madhavaram and H. Idriss, Stud. Surf. Sci. Catal. 110, 265 (1997)) over -UO3 indicates the presence of two routes for making furan from C2 compounds: one via aldolization and the other via oxidative coupling. © 2002 Elsevier Science (USA).

PainKilla - 9-2-2005 at 15:04

Some things that are pentoses includes:



Also something of interest is that xylan goes by the name hemicellulose. Pentosanes are also found in DNA, though we wont be using that method :D. I have seen some stuff that says perhaps xylitol could be used, but they had no references and I cant seem to find them anyway :p.

I will see if my health food store has it and see if this is indeed possible :D.

JohnWW - 9-2-2005 at 23:58

Xylitol is used as a substitute for ordinary sugar (sucrose) in some peppermints I have seen in supermarkets. It is used because it does not cause dental decay; the decay-causing bacteria cannot metabolize it to carboxylic acids (like lactic acid).

With regard to dimerizing acetylene to furan over UO3, presumably made from depleted uranium (nearly pure U-238), and presumably with a source of oxygen to give the formula C4H4O (if from the UO3 as a catalyst, it would have to be re-oxidized), does anyone knows of an outlet that sells UO3? I am aware of uranyl (UO2++) salts being available as analytical reagents and for use in photochemistry.

[Edited on 10-2-2005 by JohnWW]

BromicAcid - 14-10-2005 at 18:29

Just something I've been thinking over, disregard this if I've posted it elsewhere on the forum. But what about making THF from diethylene glycol?

The trick is of course getting the alcohol groups on the ends to somehow pop off and form a carbon-carbon bond between those ends. Much easier said then done of course. The only method I've come up with (mind you I haven't covered this material in a while) is to react diethylene glycol with phosphorus tribromide:

HOCH<sub>2</sub>CH<sub>2</sub>OCH<sub>2</sub>CH<sub>2</sub>OH ----(PBr<sub>3</sub>;)--> BrCH<sub>2</sub>CH<sub>2</sub>OCH<sub>2</sub>CH<sub>2</sub>Br

And from that little product (haloethers are nasty!) dissolve in an inert solvent and drip into a suspension of sodium metal to do a Wurtz reaction to give the THF.

BrCH<sub>2</sub>CH<sub>2</sub>OCH<sub>2</sub>CH<sub>2</sub>Br + 2 Na -----> (-CH<sub>2</sub>CH<sub>2</sub>OCH<sub>2</sub>CH<sub>2</sub>-)

Something more realistic anyone?

neutrino - 14-10-2005 at 18:52

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 - 14-10-2005 at 19:01

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?)

EtOEt vs. THF

Illegal Parkinson - 19-10-2005 at 08:22

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 - 20-10-2005 at 02:07

Thanks Ayush for the ebook!! And yeah, I'll probably read through the topic before posting next time... :D. 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.


P.S. Ayush, thanks for the rapidshare link. Yeah, its actually quite convenient for me to download from there... lol!!:P

BromicAcid - 22-10-2005 at 12:37

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
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
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.

BromicAcid - 7-12-2005 at 19:58

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?


Although the prominate reaction will likely be polymer formation.

[Edited on 12/8/2005 by BromicAcid]

BromicAcid - 9-12-2005 at 21:34

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
Alcohols with a hydrogen in the δ position can be cyclized with lead tetraacetate.<sup>196</sup> 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 (Br<sub>2</sub> or I<sub>2</sub>;) and a salt or oxide of silver or mercury (especially HgO or AgOAc),<sup>197</sup> with iodobenzene diacetate and I<sub>2</sub>,<sup>198</sup> and with ceric ammonium nitrate (CAN).<sup>199</sup>

<b>196</b> 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.
<b>197</b> 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.
<b>198</b> Concepcion; Francisco; Hernandez; Salazar; Suarez Tetrahedron Lett. 1984, 25, 1953; Furuta; Nagata; Yamamoto Tetrahedron Lett. 1988, 29, 2215.
<b>199</b> 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]

runlabrun - 12-12-2005 at 16:08

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?


BromicAcid - 12-12-2005 at 16:32

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
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.

Magpie - 2-3-2006 at 23:18

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.

Fleaker - 3-3-2006 at 13:45

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 - 3-3-2006 at 14:24

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.

Magpie - 3-3-2006 at 19:15

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]

test.jpg - 30kB

Magpie - 19-4-2006 at 21:25

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. :)

EtherBunny - 22-4-2006 at 08:03

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 - 22-4-2006 at 15:56

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_Davster - 22-4-2006 at 16:39

Yeah, it works for grignards(firsthand experiance in org lab).

EtherBunny - 22-4-2006 at 18:55

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 - 22-4-2006 at 21:26

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 - 12-4-2008 at 12:00

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]

Sauron - 12-4-2008 at 23:57

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.

LSD25 - 21-4-2008 at 20:00

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:

Furfural can apparently be oxidised to furanoic acid and decarboxylated by heating it to around 250C in acidic environments (I read this somewhere).

MagicJigPipe - 21-4-2008 at 20:28

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...

Panache - 5-5-2008 at 23:10

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 - 23-6-2008 at 14:41

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?

Triflic Acid - 19-11-2020 at 09:20

I know this thread has been inactive for 12 years, but is there any way of converting the spandex polymer, which is made from THF, back to THF?

ArbuzToWoda - 19-11-2020 at 09:23

Where did you get the information that spandex is made of THF? It's an urethane containing polymer, look at the attachment.

edit: now I see what you meant, but I wouldn't expect there to be such a way. Spandex structure doesn't have any tetrahydrofuran-like rings at all.
media_73b_73be5753-6e18-40fb-ae81-bf6554467b8a_image.png.jpg - 79kB

[Edited on 19-11-2020 by ArbuzToWoda]

thf.PNG - 171kB

[Edited on 19-11-2020 by ArbuzToWoda]

SHADYCHASE54 - 20-11-2020 at 08:47

If anyone in canada requires THF, DMC, glacial acetic acid, toluene and or acetone etc.. I can give you a company name that will ship to individuals without issue. I ordered 4l THF a few years back , the company was a reseller for a chem supply company out east. Prices are reasonable and product is pure. Also they are not a chemical supply company themselves. Just figured I'd offer so long as you don't plaster their name all over SM.

[Edited on 21-11-2020 by SHADYCHASE54]

zed - 3-12-2020 at 01:15

The Furfural link at the beginning of this discussion, no longer links to a Furfural Synthesis.

This is the correct link:

Furfural to the Carboxylic Acid:

The Carboxylic acid to Furan:

[Edited on 3-12-2020 by zed]

[Edited on 3-12-2020 by zed]