Antoncho (Official Hive Translator)
01-14-02 20:45
No 256342
      Methylation of hydroquinone w/NaMeSO4: good news!  Bookmark   

This is a continuation of the thread, starting with Post 218257 (PolytheneSam: "ArOR, Alternatives to dimethyl sulfate", Novel Discourse).

Antoncho, on SWIM's beehalf, would like to thank very much PolytheneSam, who not only found the original article dedicated to the subject, but also was of great feedback/support in discussion of this most interesting issue.

Here is a summary of my wife’s patient’s (she’s a psychiatrist:)) wet dream last night:

150 ml (3 moles) of 92% H2SO4 were poured in portions into 150 ml (slight xcess) CH3OH w/stirring/icebath cooling. While the mxtr still hot, 80 g ground Na2SO4 was added to it and the whole mess was chilled w/contionuous shaking (to prevent  caking) under cold water to below RT. This mixtr was allowed to stand for 4 days with periodic shaking for the 1st 24h (actually, SWIM is now positive that it takes ~24 hours for the conversion to complete – one can judge it by the texture of Na2SO4/its decahydrate. When allowed to stand further, it turns brownish – probably some impurities, although, maybee, natural decomposition).

A significant part of this acid was wasted on various unsuccessful experiments.

125 ml (~163 g) of the said acid (it’s uncertain how much xcess methanol it contained) were chilled somewhat and added via addition funnel (rather fast dripping rate was appropriate) to 150 ml 40% w/v (0,4 g per ml) NaOH cooled in snow/waterbath so as to keep the temp at ~28 C (taking temp. tests once in a while – don’t have a 3-necked flask) and pH was continuously measured to prevent it from beecoming acidic.

A side note: thus far, and from here on very precise care was taken not only to follow strictly the directions given in the article discovered by PolytheneSam, but also to strictly measure the amt. of the reagents – esp. the alkali. One has to bee precise, ‘cause if the amt. of NaOH is too small and pH gets below 7 , 50% of the whole mess will very quickly hydrolize , and if the rxn is overbasified  (taking in account that NaMeSO4 is used in 4x xcess to hydroquinone), the yield dramatically drops.

Another interesting thing is that the authors of the original article actually use an almost stoichometric amt. of NaOH to HMeSO4!! Which means that it is possible to achieve a 100% convertion to NaMeSO4 in aqueous soln!! SWIM found his result to bee at least 70%.

When adding last 10 mls pH was measured every 10 secs (in the original they used phenolphtalein, but SWIM’s local pharmacy didn’t have it so he used pH papers – tried to drop them in as well, but the stirrer quickly turned them to nothing.) All went fine until – SWIM swears – the very last milliliter, when it all of a sudden went acidic – and in maybee 5 seconds in was tossed another 5 mls of aq. NaOH, prepared beeforehand for this purpose (cool – practice is a great teachersmile), which effectively turned the pH back to basic.

This clear-and-nice solution was somewhat diluted w/water (appears that not all of the salt dissolves) filtered from the remains of pH papers and was found to bee 330 cm3 in volume. A half of it (which roughly corresponds to the amt used in the article scaled down 4x) was chilled in a 250 ml Erlenmeier flask in snow and the air inside was replaced by the used up air from the poor schizo’s lungslaugh (– they don’t have nitrogen baloons in the psycho ward). 10 g of quite  yellow hydroquinone was added and the container immediately sealed to prevent exposure to air w/ a stopper w/two holes – both plugged w/tiny stoppers. Through one of the whole w/a disposable syringe was added 18 mls of 40% w/v NaOH, cooling the mxtr (the article says ~38 C, but it was actually lower). All hydroquinone dissolved.

This was placed into an oil bath, brought to a boil (no dimethoxybenzene forming yet) and was allowed to reflux very gently (bath temp ~110 C, no need for a condenser) for an hour, while SWIM went out to purchase some grass (he’s definitely insane – grass in a hospital in the middle of winter, gosh!smile) After that time one of the holes in the stopper was opened and fitted w/a downward condenser. (The other hole was plugged not-too-tightly, it is an essential feature – condenser gets clogged w/DMB crystals every now & then, so this safety valve is needed, lest everything should blow up!)

The bath temp was raised to 120-130 C (up to 140 at the very end) and vigorous distillation was begun. DMB came over and collected w/water in a glass. Once in a while the condenser got plugged w/it and was cleared w/a spoke or, alternately, by emptying the condenser and leting the steam melt the crystals. It should bee watched, not continuously, though.

The distillation was continued for 4 hours, boling water was gradually added to the rxn through a syringe as distillation proceeded (3 h in the original, but it was still coming over then, moreover – SWIM wanted to avoid the xtraction of the rxn, as toluene is a pain to evaporate in one’s bedroomcrazy so he just wanted to steam-distill as much as possible and abandon the rest.), after which time the flow of DMB crystals considerably weakened, although not stopped completely. 200 mls of clear distillate was collected.

This was filtered through a piece of cloth (now, SWIM ran out of filters, so he just had to use whatever he had) to leave a white mass, which was pressed through the same cloth/a stack of paper towels very thoroughly two times. The crystals – clean and white - were cut w/a knife and allowed to dry somewhat. Impatient weighing of the still somewhat moist material showed them to weigh 7,5 grams.

SWIM estimates from his experience that there’s probably around a gram of water still left there, and he’ll leave it overnight to air-dry , hoping that not much will sublime. However, the distillate, saturated w/NaCl, gave an instant clouding – and indeed, it is supposed to contain another half gram of DMB – it’s soluble in aq. ~1,5 g/1000 ml. SWIM doesn’t know if he’s gonna extract it yet (or what is more valuable for him – a 0.5 g of DMB or 50 mls of DCMsmile), but it definitely is there.Edit: in the morning the crystals weighed 6.8 grams, although still not completely dry.

So, if his guess is correct (it will bee known tomorrow), he got a yield of  ~56%.

Suites him, to say the least!coolsmiletongue He has seen this fucken dream not less than six times beefore! This was the 1st to end wellsmile

Oh my dear fellow beez!

(Master Searcher)
01-15-02 03:14
No 256499
      Re: Methylation of hydroquinone w/NaMeSO4: good news!  Bookmark   

Congratulations, Antoncho.  I still think it would be best to mix the hydroquinone and NaOH together in a water solution before adding them  to the Na(CH3)SO4 (1 mole of hydroquinone to every 2 moles of NaOH).  At least you didn't add the NaOH to the Na(CH3)SO4 first.
Also, look at these posts on the Friedel-Crafts reaction and chloroacetone.  Post 255456 (PolytheneSam: "Re: Substituted P2P's:  Would this work?", Novel Discourse) Post 255616 (PolytheneSam: "Re: Substituted P2P's:  Would this work?", Novel Discourse) Post 255661 (PolytheneSam: "Re: Substituted P2P's:  Would this work?", Novel Discourse)
(Hive Bee)
03-22-02 12:33
No 286376
      Methylation of hydroquinone w/NaMeSO4  Bookmark   


Maybe you want to elaborate on your comments to Antocho as it seems he did exactly what he shouldn't have. (Add the Acid to NaOH first)

Have you got a better way to perform this procedure? What would you say is the best indicator to use during the nutralization?

Swim is dreaming huge dreams from this
(Official Hive Translator)
03-22-02 13:45
No 286383
      Neutralization.  Bookmark   

... if you mean this post, then Sam said nuthin about neutralization - he just said that pre-forming HQ-Na salt would bee a better way.

Now, for  the neutralization itself - as i mentioned bee4, it can bee done w/95+% yield (actually, in the original article it's done this way!) - the key to success is stirring - as fast as possible, and good chilling - well beelow the mentioned 28 C is completely ok (and maybee even better!)

The indicator to use is phenolphtalein. Add very very little - at 1st, when it's cold (SWIM pre-chilled all of his reagents in a freezer to ~0 C) - you may think that you won't see the difference - but as the neutralization proceeds and heats up, it will turn very red. Just the very tip of the knife - maybee, size of two matchheads.

When it's done, you'll notice a heavy precipitate - that's right, water doesn't dissolve that much NaMeSO4. Add more water (to 500 ml volume per 150 g of acid) and then filter out some junk that will bee present.

SWIM haven't tested thus NaMeSO4 yet, but the math shows success (and phenolphtalein CAN bee just left there - as the original article shows).

(Hive Bee)
03-24-02 08:01
No 287212
      Neutralization  Bookmark   

Did you filter the MeHSO4 from the Na2SO4 before neutralizing it with NaOH or did you just neutralize the post reaction mix.

I now have a very viscous white creamy liquid in the flask and this mess does not seem filterable. Do you think that this will interfere with the HydroQ reaction to form p-DiMeOBenzene.

Swim does not own a vac buchner!!frown

I will try to form the HydroQ Na salt first and report back. (that's when I've got this damn acid clean)
(Official Hive Translator)
03-24-02 10:51
No 287261
      Dear Cilliersb!  Bookmark   

1st, you absolutely MUST have a vac filtering facility to do chemistry. This is out of question.
SWIM also doesn't have a vacuum source, so he made a device from two bottles - a large and a smaller one, with a crane in between. The small one is where you stick you Buchner, from the larger one you remove air suckling w/your mouthcrazycrazycrazy, then open the crane... The device sucks (pun intendedsmile), of course, but it is at least some substitute - until SWIM gets smth more decentlaughlaugh

But, i'm happy to tell you, you don't need to vac filter the mixtr - just let it sit for 2 days and decant. The Na2SO4 will form a sticky sludge, so you can decant all of the acid w/out getting in any Na2SO4.

(Master Searcher)
03-24-02 15:15
No 287306
      lambastic protogenesis  Bookmark   

It starts here Post 218257 (PolytheneSam: "ArOR, Alternatives to dimethyl sulfate", Novel Discourse) .  Look at the British patent.  I also like the idea I had about making dimethoxyphenylacetic acid.  Post 273091 (PolytheneSam: "Electro hydroquinone method", Novel Discourse)
Also see Post 258134 (foxy2: "New preparation of phenylacetic acid", Chemistry Discourse)
ad terra incognita per ars artis gratia
(Hive Bee)
03-25-02 08:52
No 287553
      lambastic protogenesis  Bookmark   

Thanks Antocho.

I was kinda wondering if the whole mess will settle. Hoping to buy a buchner today with a nice filter flask.

Decanting is the way to go then I guess.

Oh Sam

I followed that thread very closely as well. Thanks for the feedback and post shortcuts, they really make life easier.

As for obtaining Hydroquinone, swim has 1/2 kilo to play with. More can be purchased for very little too. I'll keep the Benzene electro in mind for dryer times.

Thanks for the help beezsmile
03-26-02 22:21
No 288236
      hi antoncho, (late) congratulations from otto.  Bookmark   

hi antoncho,

(late) congratulations from otto. what are your plans with the Dimethoxy? otto is sad to see, that the monomethylation is not further followed, so he bought some HQ to start a trial.

(Hive Bee)
03-27-02 09:29
No 288453
      NaMeSO4  Bookmark   

Some news and things to consider.

Swim did not filter his acid before using it. He just checked in the whole shebang into Water containing the Na salt of Hydroquinone. Heated this on a boiling water bath for 3 hours. Upon adding DCM to the cooled post reaction mix a thick precipitate formed on shaking. Swim is still not sure what this was, but adding a little dcm/THF 80:20 dissolved the precipitate. The solutions were separated and the bulk of the dcm/THF distilled off.

The last 25ml or so was evapped in a large watch glass and impure crystals of p-diMeOBenzene were left. The unpurified product weighs aroung 4.6g. (from 20g Hydroq, very bad yeild)

These crystals are very light amber colored. I've worked with reagent grade p-diMeOBenzene before and this is definitely it, just not pure yet. This goes to show that this synth is very robust and will yeild at least 10% or more, even if you push your luck like swim.

Any ideas on a suitable recrystalization solvent anyone?
(Official Hive Translator)
03-27-02 09:55
No 288458
      Plans and stuff  Bookmark   

Dear Otto!

Actually, Someone Who Isn't Antoncho doesn't have any plans for his dimethoxy (he once considered making some SOCl2 from SCl2 - but since that came to bee an unreliable way, he decided to abandon the project. He has no source of POCl3 or COCl2 crazy) Some day, i think, he might try to acetonylate it w/Mn(AcO)3 - but not in the immediate future.

Duff formylation in aq. acetic won't work - even if you reflux it for 24 hours.

Another, very sexy, possibility, would bee to brominate + chloromethylate (both steps described in literature, and even posted here, IIRC) + Sommelet to aldehyde and further as known (actually, Shulgin has an example using specifically 4-bromo-p-DMBA); or - if you have some NaCN lying aroud - convert to nitrile and reduce with, say, hydrazine hydrate/Ni.
Unfortunately, the reagents involved in this procedure are rather stinky and poisonous/carcinogenic (although there is a safe way to chloromethylate now :)), so SWIA hasn't a desire to do this in the immediate future either.

As for monomethylation - it isn't abandonned at all, AMOF, that's what SWIM is currently dreaming of, and soon will bee posting. (If you notice, dimethylation came first, in chronological order) The major stumbling block was purification of crude p-MeO-phenol - that's why it was postponed for a while. But you will know about it soon, in the proper threadwink

(Official Hive Translator)
03-27-02 10:04
No 288459
      Whut??  Bookmark   

Cilliersb, you mean you dumped the fucking acid  into HQ-Na salt???

That's so funny, cause i always thought one needed Na-methylsufate to alkylate... At least, that's what SWIM used.

You mean, the solution was acidic?? Or there was a huge excess of NaOH in the mixture?

Water destroys methylsulfuric acid. Beesides, alkylations like that are always done in alkaline conditions.

As for rextallization - just steam-distill it - it won't take long, the stuff is fond of vapourizing.

Please, elaborate - BTW, you might notice the reaction is actually properly performed w/steam-distillation from the very beginning - not like you did it.

(Hive Bee)
03-27-02 10:04
No 288460
      POCl3  Bookmark   


This is exactly what swim was dreaming. p-diMeOBenzene + POCl3 -> p-DiMeOBenzaldehyde.

POCl3 and SOCl2 can be made from PCl5 and SO2. PCl5 is not that difficult to obtain and SO2 can easily be genrated.

Wanna try this?
(Hive Bee)
03-27-02 10:27
No 288466
      NaMeSO4  Bookmark   


This is simple acid base chemistry the way I see it. Yest the reaction ran basic. I first dissolved HydroQ in H2O/NaOH. This formed the disodium salt of Hydroquinone and since NaOH was in excess, the solution was still quite alkaline.

The 1Hydroquinone salt(slightly basic) reacts with 2MeHSO4 (acid) forming 1 p-diMeOBenxene 2H2O and sodium sulfate.

This is what PolySam suggested in earlier this post to you. Now I'm suspecting that this synth can be made to give an almost perfect yeild. By simply calculating the exact quantity of the MeHSO4 by titration. Adding 3mol of MeHSO4 for every mol HydroQ (50% excess acid). Use a slight excess of NaOH (enough to form the HydroQ salt and maintain basic conditions even with the excess acid and residual H2SO4). Add NaOH to Hydroquinone and make sure all the hydroquinone dissolves first.

Now add your acid and perform the rest of the procedure as before. The only real advantage to this method is that you reduce the risk of hydrolizing 50% of your acid during the neutralization. (cuts out the neutralization step and replaces it with a titration instead.)

Swim will try this in the coming weeks and report back.

Any ideas on experimental details of PCl5 + SO2 -> POCL3 + SOCl2 ?

Remain cool Beez

(Hive Photographer)
03-27-02 11:45
No 288481
      experimental details of PCl5 + SO2  Bookmark   

Any ideas on experimental details of PCl5 + SO2 -> POCL3 + SOCl2 ?

in Blasius, Unorganische Chemie, this rxn is described. Uemura hasn't the book at hand now, but it's not difficult. In summary, put SO2 over PCl5 until all PCl5 has dissolved. Then do fractional destillation. Faction 1 will be SOCl2, fraction 4 POCL3. 2 + 3 are again frac dest. You may PM me for details if interested.

Carpe Diem
(Official Hive Translator)
03-27-02 13:05
No 288500
      Unfortunately, PCl5 IS very difficult to obtain wh  Bookmark   

ere i live :( Prohibitively expensive.

(Hive Photographer)
03-27-02 14:26
No 288525
      PCl5 IS very difficult to obtain  Bookmark   

Uemura knows you need something to start with. IMHO if you can't get PCl3 then forget about synthesing PCl5, POCl3 and other phosphour based oxy/halide derivates. Then just the SOCl2 looks more to bee a possibility, at least useful for acide chloride preparations.
Carpe Diem