Author Topic: An easy OTC 2,5-diMeO-phenylmercaptan  (Read 4603 times)

0 Members and 1 Guest are viewing this topic.


  • Guest
An easy OTC 2,5-diMeO-phenylmercaptan
« on: August 26, 2001, 09:07:00 PM »
Ladies and gentlemen!

Let me proudly present you a small research.

Look what i've found on Espacenet GB994506 (the temperatures look funny sometimes, but you can make them out):

Aromatic mercapto compounds are made by reacting a phenol or a phenol ether, which contains at least one hydrogen atom in ortho or para position to the -OH group or ether group, with a sulphur chloride and hydrogen sulphide at a temperature in the range of from -50 DEG C. and + 200 DEG C., recovering the poly-sulphide formed and reducing the polysulphide to the mercaptan. The phenols used are mono or polyhydroxy phenols of mono- or poly-nuclear aromatic systems in which the hydroxy groups may be etherified partly or entirely with aliphatic or aromatic radicals. They can be substituted by alkyl or aryl radicals or by halogen, mercapto- and alkyl(aryl)-mercapto groups. Suitable examples are given. The process may be effected with or without solvents. A Lewis acid or proton acid may be used as a catalyst, particularly FeCl3,AlCl3, ZnCl2, SnCl3, BF3, H2SO4 and H3PO4. The polysulphide may be reduced to the mercaptan by reaction with nascent or catalytically activated hydrogen, with hydrogen sulphide and its alkali metal salts, with grape sugar and with alkali metals or alkali metal amalgams.

Cool, huh? Considering that sulfur chloride can be easily made from sulfur/chlorine (pass dry Cl2 over S at 120 C, distill off S2Cl2  at 136 C) and H2S - from iron turnings and sulfur, it's funny to say that, but it is a completely OTC procedure! Not for a beginner chemist, though:

108 parts by weight of anisole and 150 parts by volume of methylene chloride and 103 parts by weight of sulphur chloride in 200 parts by volume of methylene chloride were introduced dropwise into 200 parts by volume of methylene chloride in the presence of 7 parts by weight of aluminium chloride at 380C., 22400 parts by volume (=34 parts by weight) of hydrogen sulphide being introduced.
The total reaction time was 4 hours, the mixture was then stirred into 2000 parts by volume of water and filtered off from 9 parts by weight of sulphur. The aqueous phase was extracted with methylene chloride. After hydrogenation of the combined organic phases (3 hours at 1500 C. and 100 atmospheres of hydrogen using 30 parts by weight of cobalt trisulphide as catalyst), the products were worked up as in Example 1 and 58 parts by weight of 4-mercapto-anisole (B.p. 88--900C. at 5 mm Hg. 54% of theoretical, calculated on the amount of conversion) were obtained.

They also say benzene may be used instead of DCM, 1,5 times as much is needed.
Well, as far as the reduction step goes, of course, hi-psi hydrogenation sucks, fortunately,

The reduction of polysulphide to mercaptans could also be carried out with the aid of Na2S. In this case, the polysulphide solution was stirred with excess Na2S dissolved in water. Owing to the alkalinity of Na2S, the polysulphide went into the aqueous phase as a phenolate. When the reduction was complete, the solution is neutralised and the mercapto compound was obtained from the organic layer as above.

8)  8)  8)
Now, note that in this patent the need for H2S introduction was explained as follows:

...The reason for this is that the action of sulphur monochioride on phenols and naphthols does not lead to the formation of di-(hydroxyaryl)-disulphides, as would be expected from the reactants, but results in disproportionation reactions and deposition of sulphur to form mixtures of mono- and polysulphides in which the monosulphide content predominates.

(H2S introduction interferes w/disproportionation)

OK, ladies and gentlemen now that you've read that far, comes the time for the final trick:


The present invention relates to a process for the synthesis of the intermediates 4-hydroxy-thiophenol, 2,6-dimethyl-4-mercaptophenol,<et cetera - phenols only, no ethers>,which comprises reacting sulfur chloride and the corresponding phenol or naphthalenol in methanol, then reducing the products in mineral acid, such as hydrochloric acid, in the presence of zinc metal.

The reason that phenolic comp'ds don't disproportionate in this case is found in the previous patent:

...It is also possible to use solvents which themselves react with sulphur chlorides, e.g. alcohols or ethers, provided that these reactions are considerably slower than the reaction of the process according to the invention and provided the sulphur chloride is added to the dissolved hydroxyl-containing components which are present in excess.

In contrast w/the 1st patent, everything here is very simple:

General Procedure: Step 1 - Preparation of 2,3-Dimethyl-4-mercaptophenol
To a solution of 2,3-dimethylphenol (10g, 81.9mmoles) in anhydrous reagent grade methanol (200mL) at room temperature was added dropwise sulfur monochloride (4mL, d=1.688 8/mL, 135.03g/mol, 50.0mmoles). The reaction was mildly exothermic and the color became somewhat darker. The mixture was stirred at room temperature for about one hour and was examined by analytical thin layer chromatography eluted with 20% ethyl acetate in hexanes (v/v). TLC showed no starting material and the formation of two other spots was evident. The crude mixture was evaporated to one half of the original volume and was diluted with 200ml of diethylether and 100ml of distilled water. The heterogeneous mixture was subjected to the next reduction step without further purification.

The heterogeneous sulfuration mixture was treated with granular zinc metal (20g, excess) and 100ml of conc. hydrochloric acid at room temperature for about 16 hours. When the reduction was complete (monitored by TLC), the organic layer was separated, washed with water to remove as much zinc residue as possible. The organic layers were combined, concentrated and the crude product was preabsorbed on 40g of fine silica gel (type-H). The desired product was purified by silica gel column chromatography eluted with 5% ethyl acetate in hexanes (v/v), 5.5g of the title compound was isolated (36mmoles, 44%). The product could be further purified by crystallization from ethyl acetate and hexanes.m.p. = 98-99 DEG C;

On the downside here, we want a mercaptane of an ether (you know which one :) ), not a phenol (BTW, dihydroxy compds can't be used in this rxn). On the up-side, dimethoxybenzene nucleus is much more activated than anisole's, and then let me quote the #1 one more time:

Although the free hydroxy compounds generally react even without a catalyst, a catalyst is usually advisable for the reaction of the ethers.

Catalytically active compounds which can be used for the first stage of the process according to the invention are such Friedel-Crafts catalysts as proton acids and Lewis acids. Particular examples to be mentioned are iron-(III)-chloride, aluminium chloride, cinz chloride, tin chloride, boron fluoride and anhydrous sulphuric and phosphoric acids. Solid catalysts may be used in the form of a fine powder or in solution

Well, L&D, i want to ask you only one question: will any Lewis acid bee of use here (like will ZnCl2 react w/methanol and will it interfere w/its activity) If so, than it seems that 2,5-dimethoxyphenylmercaptan can be made by reacting 2,5-dimethoxybenzene with S2Cl2 and ZnCl2 in MeOH and then reduced w/aq. Na2S. That could bee IMHO a breakthrough in 2C-T's chemistry! :)  
Someone i Have Known And Loved has recently made about 60 g of S2Cl2 from sulfur (from the gardening section of his local market), conc. HCl and pool shock and says even a baby can do it (having blown it up the 1st time he did it  ;D  ;D  ;D )

OK, that's finally it.



  • Guest
Re: An easy OTC 2,5-diMeO-phenylmercaptan
« Reply #1 on: August 28, 2001, 12:50:00 AM »
Just to keep the excitement alive, I'll ask a coupla questions for non-chemists:

~Just what the hell does that drug do to human being, who, lets say, after finishing this syhnth in the name of science, suddenly flips out b/c of poisonous vapors and eats some?

~The first or 2nd step requires a hydrongenation:  does your disclaimer warning its not for the beginner ward off any those seeking to claims its not 100% OTC?


  • Guest
Re: An easy OTC 2,5-diMeO-phenylmercaptan
« Reply #2 on: August 28, 2001, 04:44:00 AM »

~Just what the hell does that drug do to human being, who, lets say, after finishing this syhnth in the name of science, suddenly flips out b/c of poisonous vapors and eats some?

It is not a drug but a precursor to the whole Aleph/2C-T family, a most valuable one, should i say! In PiHKAL, Shulgin uses fucken sulfuryl chloride (SO2Cl2), which, BTW, can't bee made OTC, followed by reduction w/Zn - both rxns are very stinky and, it's been SWIM's impression that they aren't for a kitchen chemist in any imaginable way.

Here you have an easy and OTC way of introducing -SH group into the nucleus, which makes 2C-T's and Alephs - well, at least, not out of theoretical reach of a kitchen chemist, which i consider to bee a major step ahead in our holy war.

...a hydrogenation:  does your disclaimer warning its not for the beginner ward off any those seeking to claims its not 100% OTC?

HELL, NO!! It is 100% OTC - in theory, that is. Reduction of poly-/di- sulfides can bee easily accomplished either with aq. Na2S or with Zn in aq. HCl - both procedures are stated in my post explicitly.

Damn it, i definitely should have made it shorter - people here seem not to bee fond of reading, really :P .

Thank you very much for your reply, Gen_Washington, when SWIM makes some 2C-T-7 he'll send you a sample by mail - 2C-T's are actually legal, aren't they? - well at least they're sold freely in Internet shops and not listed in any fucken lists (russian too;).

Luck to you,



  • Guest
Re: An easy OTC 2,5-diMeO-phenylmercaptan
« Reply #3 on: August 28, 2001, 07:59:00 AM »
How do you control the formation of S2Cl2 so that SCl2 is not produced instead? Could we have a writeup of your disulfur dichloride synthesis?


  • Guest
Re: An easy OTC 2,5-diMeO-phenylmercaptan
« Reply #4 on: August 28, 2001, 03:21:00 PM »

Shulgin uses fucken sulfuryl chloride (SO2Cl2), which, BTW, can't bee made OTC, followed by reduction w/Zn - both rxns are very stinky and, it's been SWIM's impression that they aren't for a kitchen chemist in any imaginable way.

Shulgin uses chlorosulfonic acid to make 2,5-dimethoxythiophenol from 1,4-dimethoxybenzenze. Chlorosulfonic acid is indeed non-OTC,
and is a nasty but non-smelly chemical (think H2SO4 on a meth binge). But the reactions are so simple anyone with a year of chemistry could do them. And the first reaction does not stink at all. The only thing which isn't clear from shulgins writeup is that the first step (with chlorosulfonic acid) is better performed in a large beaker, instead of a three-necked flask. Much gas evolution.

The Zn reduction is indeed a bit smelly, but it is doable. Main bottleneck here are the extractions.It has been my experience that most of the thiol is in the first chloroform extractions (which are then the top layer). If you add to much water to avoid emulsions, a lot of thiol will remain in the water layer, and you can't get it out.

If chlorosulfonic acid is out of reach, you could also brominate 1,4-dimethoxybenzene, and then form the grignard reagent and add an equivalent of S. Workup with HCl. Disadvantage: extremely smelly.

Another (non-OTC) option is the route described for 2ct-9, using the appropriate disulfides, if you think chlorosulfonic acid draws to much attention.


  • Guest
Preparation of S2Cl2
« Reply #5 on: August 28, 2001, 05:59:00 PM »
First let me thank yellium for his very appropriate, clever and useful comments - i totally agree w/everything he said, but will still stick to sulfur monochloride.

Now, as to how SWIM made S2Cl2.

Dear Rhodium! The thing is that sulfur monochloride is the most  and the only stable chloride of sulfur. SCl2 is indeed formed when S2Cl2 is saturated w/Cl2 but first chlorine merely dissolves and reacts only gradually. So, as long as sulfur is present in the rxn mixture (which is to say, at any time) there's simply no chance at SCl2 formation. But i still consider it to bee an interesting possibility - SCl2 is a yet stronger Lewis acid and it looses chlorine more readily (i'm afraid though since SCl2 is unstable some chlorine could bee formed and that it would bee of course bad). All data comes from my Good Old German textbook - a good one, indeed. Now - the procedure:

60 g sulfur (tech grade, from gardening store) were placed in a 250 ml Erlenmeyer flask on an oil bath set at ~120 C. The flask was stoppered w/a rubber stopper w/two holes: the 1st hole was fitted w/a lead-out tube for draining excess chlorine, its other end was put into a small flask containing aq. ammonium sulfate, the tube not touching the liquid.
Into the 2nd hole there was inserted a chlorine lead-in tube that extended to just above (NOT below!!!) the molten sulfur. It was connected through a vial filled w/CaCl2 to the chlorine generator, which consisted of two ketchup bottles connected w/a crane and a network of tubes :)  . Cl2 was generated by dripping 3x75 ml conc. HCl onto 3x37,5 g dry pool shock (CaCl(OCl)) - that is, the addition funnel was charged three times w/75 ml HCl etc. each time. The pool shock's active chlorine content was stated to bee 45-52% (this number represents how much Cl2 is generated on treatment of it w/conc. HCl - important to know, since HCl is partially oxidized in the rxn producing extra chlorine).

When all sulfur has melted -mp 110 C, which took quite a while, HCl was allowed to drip into the CaOCl2 at, say, 1 drop per second. As Cl2 began to reach the flask initially a small quantity of SO2 came out, but very soon it was only Cl2. BTW, ammonium sulfate does a shitty job of neutralizing chlorine -caustic Na2SO3 was tried but it only worsened everything, giving off SO2 in quantity. Any suggestions? Next time SWIM'll try to use activated charcoal - probably should have started w/it in the 1st place.

This chlorination took well - SWIM's not sure, just drip HCl at the speed at which not much Cl2 comes out of the rxn - in fact, slower than 1 drop per second, SWIM thinks. Then the dripping funnel was recharged and evrth'ng was repeated 2nd and then 3rd time.  During the rxn it was observed that when the bath temp accidentally rose above 130 C (SWIM can control his temp only w/his gas oven's valve) heavy vapors of yellow color began to condense on the flask walls and in the lead-out tube. S2Cl2's bp is 136 C so it was a sure sign of success. By the end of the 3rd chlorination on cooling the mixture stayed a dark reddish yellow liquid (just like S2Cl2 should bee) with quite an amt of sulfur floating in it. It was estimated that, given that S2Cl2 dissolves sulfur 4:1, about a half of all sulfur reacted. Initially SWIM planned to make four runs (aiming for theoretical amt of chlorine necessary for 60 g S) but, since Cl2 absorption rate dropped considerably, he decided to stop at that point.

And one more important point. Some curious bee will surely ask me why pass Cl2 over sulfur, why not just bubble it into it for better absorption? Antoncho will enjoy telling him exactly why. Since incoming Cl2 has a room temperature, it continuously chills the lead-in tube and, if its tip is immersed in molten sulfur, it will very quickly bee plugged up w/sulfur crystals. Then the pressure will build up and eventually blow out some of your apparatus' stopper - in SWIM's case it was the bottle with HCL - turned, BTW, upside down... "Honey, what was that sound, huh?.." Kitchen can bee a funny place sometimes! Fun, fun, fun... ;D  ;D  ;D

Well, at the present moment SWIM's S2Cl2 still stands there in the rxn flask. The reasons for this are two. 1st, SWIM doesn't have at the present (soon will) an all-glass distillation equipment, and S2Cl2  dissolves just about anything - rubber and PVC for sure. Actually, the stopper in the flask turned to fucken EBONITE  just from contact with its vapors. And the 2nd reason - a very-very slight odor of it immediately made SWIM quite nauseous. SWIM needs to bee alone at home for distilling it 'cause he thinks that his beloved ones won't appreciate his playing around w/this infernal  substance ::) .

That's it for now. Bee sure to check out Antoncho's thread about Vilsmeyer mechanism for some new interesting info ;)



  • Guest
Re: Preparation of S2Cl2
« Reply #6 on: August 28, 2001, 06:14:00 PM »
Do you have the proper equipment for distilling the S2Cl2, so that you can get an approximate yield of the chlorination reaction, and so that the S2Cl2 will be become pure enough for use in the next step?

If you want to neutralize chlorine gas, I would suggest you just use a gas dispersion bubbler in a flask with 20% NaOH (with a suck-back trap inbetween). Cl2 + NaOH => NaOCl + NaCl. It would also neutralize any formed SO2.

I think this project is highly interersting because it is so novel, regardless of the drawbacks of using so nasty chemicals.


  • Guest
Re: Preparation of S2Cl2
« Reply #7 on: August 28, 2001, 10:16:00 PM »
Disulphur Dichloride is very easy to prepare exactly the way Antoncho stated. Swic has done it many times, however it can be easily done all insitu (As the S2Cl2 is formed, it is automatically distilled). A wide mouth gas dispersion tube(no fritted disc) is fitted on a side arm of a 3-neck flask filled with molten sulphur and the chlorine gas is BUBBLED through the liquid. A reddish colour liquid will form a layer and as the temperature is brought up it will boil off. A 3 way adapter is fitted on the center neck of the 3-neck and the S2Cl2 is collected. Note sulphur melts at about 115C and disulphur dichloride boils at about 136C, so one must raise the temp of the melted sulphur up to about 140C. Swic made it once very easily when attempting to make mustard gas (not a good idea  ::) ). SCl2 is of no concern in the reaction because it is only formed in the presence of iodine or metal chlorides.
Antoncho said not to bubble the gas through the sulphur because it solidifies the molten sulphur and causes the gas generator to explode. However, when raising the sulphur to about 150C, so that the S2Cl2 distills off, this problem just doesn't occur because any solid sulphur immediately melts back to the liquid phase (don't bubble the chlorine in too fast either). Also that is the reason you don't want to use a fritted disc gas dispersion tube, and instead a open mouth tube. DON"T raise the sulphur above 160C, as it will begin to turn dark brown and possibly dangerous.
Anyways, swic wishes you the best of luck Antoncho. Really looks like a great idea  :) .


  • Guest
Re: Preparation of S2Cl2
« Reply #8 on: August 29, 2001, 12:55:00 AM »
Great work, Antoncho, and catastrophe too! We need more of these practical, hands-on reports about preparing these reagents which people don't want us to have, so we don't have to play their phoney bogus cops'n'robbers games with acquisition.

"Shulgin uses fucken sulfuryl chloride (SO2Cl2), which, BTW, can't bee made OTC", does that mean you don't consider gas phase reactions (in general) achievable OTC? As I said, SO2 + Cl2 --> SO2Cl2 in gas phase. Oh, if I were without all-glass apparatus, I would bee very hesitant, also, to experiment with many of these very hazardous compounds. (I should hesitate more than I do, considering my track record of not-funny lab mishaps.) Your courage is commendable, Antoncho, under the circumstances.

Is there a reason we risk our health and happiness, our reputation, our future freedom and our very lives, in our quest to understand these obscure aspects of the natural world? Do we have a cause we are fighting for? I think so, beez. Many of you will not identify with my mystical interpretation of spiritual struggle, but I do think we can all unify at a more abstract level, that we fight for freedom.

turning science fact into <<science fiction>>


  • Guest
Re: An easy OTC 2,5-diMeO-phenylmercaptan
« Reply #9 on: August 29, 2001, 03:48:00 AM »

when SWIM makes some 2C-T-7 he'll send you a sample by mail

You know what Antoncho, I'm with Gen_Washington. Maybe you should prove me wrong too by sending me a sample. ;)  30mg might be enough to convince me  ;D . Swic went through your proposed plan much more carefully this time, and must admit it looks great. The hydrogenation to the mercaptan(Jesus look what you've made me say Antoncho!) thiol seems so simple too...

The polysulphide may be reduced to the mercaptan by reaction with nascent or catalytically activated hydrogen, with hydrogen sulphide and its alkali metal salts, with grape sugar and with alkali metals or alkali metal amalgams.

Ahhh, alkali metal amalgams, wonderful. And hey that's another 5mg in the mail for making me say mercaptan mate!

And to the "Ubiquitous Precursor Medal Winner", I take my hat off to your, correction, OUR struggle!


  • Guest
Re: An easy OTC 2,5-diMeO-phenylmercaptan
« Reply #10 on: August 29, 2001, 01:26:00 PM »
Ladies & gentlemen!

I am ashamed to say that, but evidently SWIM's method of producing S2Cl2 isn't as good as he stated it was.
"...Sulfur doesn't just dissolve in S2Cl2 but enters its molecule, the products of formula S3Cl2 and S4Cl2 are mainly formed... has obtained them in dry form as their complexes w/AlCl3" - this is what SWIM's G.O. German textbook says right after the paragraph about S2Cl2.

Well, apparently if SWIM'd put some more attention into reading it, he wouldn't have made such a mistake. Tonight SWIM assembled a whole-glass apparatus for distilling off his S2Cl2 and - alas! - it didn't show a slightest sign of boiling at as high as 155 C. Well, obviously, during the 3 days the shit's been standing in the flask all S2Cl2 has reacted to polysulfides. Damn!

Antoncho thinks that the next thing SWIM does will bee trying out Catastrophe's variation w/what he currently has - at least now you can not worry about sulfur plugging the chlorine tube.


P.S. Hey, Catastrophe, i guess that'll bee another 20 mg for you ;)


  • Guest
Re: An easy OTC 2,5-diMeO-phenylmercaptan
« Reply #11 on: August 29, 2001, 07:19:00 PM »
Antoncho, what swic usually does for the Cl2 generator is add some water to the hypochlorite before adding the HCl. Put some hypochlorite in your flask, then add about 25mL of water to it and stir it up to make a milky suspension. Now drip your HCl in there (nothing will happen the first couple of drops, but after that copious amounts of Cl2 are generated). This allows for more controlled addition of Cl2, so that you can bubble it in slower. Good luck!


  • Guest
Making SO2Cl2
« Reply #12 on: August 30, 2001, 12:50:00 AM »
It can be done, however you better have a good fume hood cause you'll be working with some very nasty dangerous gasses.

Make chlorine as described using bleach and HCl.  Combine with SO2 and condense out the SO2Cl2.  I would combine the gasses at the top of a long condenser.  Better have an aspiator to catch any excess gasses after the condenser.
This reagent can also be used for 2-CCl.

SO2 Generator
Sodium Hydrogen Sulfite(NaHSO3) can be reacted with HCl to make SO2.

Do Your Part To Win The War


  • Guest
Re: Making SO2Cl2
« Reply #13 on: August 30, 2001, 01:59:00 AM »
Procedure for SO2Cl2:

The bulbs of an Ahlin condensor are alternately filled with glass wool and granules of activated charcoal. Don't pack tightly! The activated charcoal will ensure a smooth and nearly complete conversion.
The Cl2 and SO2 are dried by bubbling them separately through H2SO4, and introducing them into the TOP of the condenser.
With the cooling water running start the gas generation. Adjust to about 3-5 bubbles per second. The coal will saturate with SO2 and SO2Cl2, and after about 10-30 mins the SO2Cl2 will start dripping out of the condensor into a two-neck flask cooled in an ice bath. Excess gas is best released into the hood through a drying tube filled with CaCl2. (Or maybe neutralised in NaOH? Maybe a second condenser, like a liebig, filled in the same way with glass wool and activated charcoal will help to insure even better conversion?)
When done correctly you can produce about 150g SO2Cl2 per hour. The yellow crude product contains dissolved Cl2, which can be removed by shaking it with some Hg (ewww, old procedure  ;)  ), or by bubbling dry N2 (or any other inert gas) through the cooled liquid. Fractionately distill through an efficient column after decanting from the HgCl2.
BP 69.1°C, colourless liquid which discolours on standing due to dissociation.

Preparation of volatile halogenides:

                   /         ______^__________## >> exhaust
     --------------          |
Cl2>###                      |cold finger condensor
    ###  sulfur              |
     --------------          ------v----------
                   \                         ##
       ^^^^^^^^^^   --------------- -----------
      heating zone                | |
                               to flask

In the slightly tilted apparatus S is heated carefully after all the air was displaced by Cl2 (dried by bubbling through H2SO4). The crude reddish product will condense and drip into the cooled flask. Stop the chlorination before all the S is used up. The crude product can be distilled after adding a little solid S.
Yellow oily liquid, BP 137-138°C. Less pure products are orange or reddish due to the dissolved SCl2. S2Cl2 dissolves up to 67% S!


  • Guest
SO2 + Cl2 ---Camphor---> SO2Cl2
« Reply #14 on: August 30, 2001, 08:39:00 PM »
Dear Osmium!

This is very, extremely cool! First of all it is a known fact that SO2Cl2 can bee used in Vilsmeier reaction.

And second, isn't it correct that by dripping methanol into this substance one would arrive to dimethylsulfate? Please, correct me if i'm wrong, but it seems to bee pretty straightforward... Have we finally found a way for OTC DMS preparation?.. Well, time will tell.

I want to add one more tidbit to this topic - a yet another SO2Cl2 synthesis. It requires camphor as a catalyst but has a definite advantage of being technically much simlpler, like, no need for 2 dripping funnels and one doesn't have to carefully adjust the speed of SO2/Cl2 emissions so that they match. Here goes:

Sulfuryl chloride.
This compound may bee obtained by taking advantage of the specific catalytic action of camphor.

10 g of finely divided camphor is placed in a small RBF plugged w/ a cork stopper w/ 2 holes, one is fitted w/a glass tube extending almost to the bottom of flask, the 2nd is equipped w/a reflux condenser. A stream of dry SO2 is passed through the tube and is almost totally absorbed. As camphor is saturated w/SO2 it turns liquid. When it is finally saturated (one wt. of camphor absorbs ~0.88 wt's of SO2 at 760 torr) through the same tube is introduced a stream of dry chlorine which is momentarily absorbed. On mixtr's saturation w/Cl2 the procedure is reapeated once again. The rxn mixtr is then distilled collecting the fraction that boils at 68-70°C. Thus prepared SO2Cl2 always containes traces of camphor from which it can bee purified by re-distillation.


  • Guest
Re: Making SO2Cl2
« Reply #15 on: August 30, 2001, 09:48:00 PM »
Hmmm, could it be that you guys are getting sulphuryl chloride SO2Cl2 mixed up with thionyl chloride SOCl2??? Thought thionyl chloride could be used in the Vilsmeier, hope I'm wrong because sulphuryl chloride seems much easier.
BTW Antoncho for OTC DMS, take a look in the tryptamine forum. Halfapint posted a gem  ;) .


  • Guest
Re: Making SO2Cl2
« Reply #16 on: August 30, 2001, 10:07:00 PM »
I take it camphar=camphor right?

Do Your Part To Win The War


  • Guest
Re: Making SO2Cl2
« Reply #17 on: August 30, 2001, 11:22:00 PM »
ooops... yes, it's camphor, not camphar.

and yes, it's sulfuryl chloride - i remember exactly that i read it could bee used on, just a brief mention.


  • Guest
Re: Making SO2Cl2
« Reply #18 on: September 01, 2001, 05:57:00 PM »
To go back to the original topic of the thread, I believe that in the second patent (EP0640590, quoted in purple) first the diaryldisulphide is indeed formed (that's why they don't need the H2S introduction), and in the second zinc reduction step, the disulfide is reduced to two arylmercaptan molecules.

Anyone trying this reaction on dimethoxybenzene should select a lewis acid that is not too strong (like anhydrous ZnCl2) so that the ether bonds are not cleaved. Also, to avoid the methanol used in the second patent reacting with the lewis acid, I suggest the use of CH2Cl2 as the reaction sokvent instead (as Osmium pointed out, it is not particularly reactive in friedel-crafts reactions).

If I write a suggested procedure for use with 1,4-dimethoxybenzene, is there anyone willing to try it out? If so, I'll write one. I don't want to work with sulfur compounds myself, but I would very much like this outline to become a working alternative for the preparation of 2,5-dimethoxythiophenol.


  • Guest
« Reply #19 on: September 02, 2001, 09:49:00 PM »

Also, to avoid the methanol used in the second patent reacting with the lewis acid, I suggest the use of CH2Cl2 as the reaction solvent instead

The 1st and the 2nd patent are essentially the same, xept
1) the 1st one uses DCM, the 2nd - MeOH 2) in the 1st patent they use H2S to get di-, not mono- sulfide and in the 2nd, it is evidenly methanol that by slowing down the rxn serves this purpose.

If one could just use DCM for this, there'd bee no reason for H2S introduction. However, looks like a Lewis acid might bee needed in case of a phenol ether... It just doesn't make sense to me - we want methanol, 'cause it inhibits the rxn and we want a catalyst to drive it forward?

A trial is indeed needed. SWIM would've gladly tried it out but he hasn't made any dimethoxybenzene yet :( . And after he does he wants to explore the Vilsmeier alternatives w/S2Cl2 first. So it won't bee soon i'm afraid... Any more volunteers?


  • Guest
Sulfuryl Chloride
« Reply #20 on: May 20, 2002, 03:11:00 PM »
I'll add to what Osmium said.
Looks like the cooling of the catalytic chamber is essential.

Damn this really sounds easy!

Catalytic preparation of sulfuryl chloride.
Tarle, M.; et al.   
Bull. Mukden Arsenal  No. 8  9 pp.  (Language unknown)
CAN 29:43098    AN 1935:43098   
The prepn. of SO2Cl2 from SO2 and Cl2 in the presence of active C as catalyst was studied with the purpose of ascertaining the possibility of industrializing the process.  With 10 g. Kahlbaum active C as catalyst, 150 g. SO2O2 was obtained in 1.5 hrs. at -10°; at 0°, the yield drops to 60 g. and at +20°, practically to zero.  The catalytic activity of the active C gradually decreases after prolonged use (10-12 hrs. or more) because of poisoning by certain by-products (HCl, H2SO4).  The catalytic power of various kinds of active C increases with its activity. 

The industrial use of chlorine by way of sulfuryl chloride.
Tantzov, N. V.   
J. Chem. Ind. (Moscow)  (1933),   (No. 1),  36-40. 
CAN 27:39469    AN 1933:39469
SO2Cl2 results quantitatively from a 1:1 mixt. of SO2 and Cl2 when charcoal is used as a catalyst.  Dense charcoal is preferable to porous varieties.  SO2 and Cl2 react directly with boiling H2O giving pure, nearly anhyd. HCl and H2SO4 without the use of a catalyst.  Large amts. of air and volatile As compds. have no effect on the reaction. 

Sulfuryl chloride.    
Kroner, Gerhard.  (I. G. Farbenind. A.-G.).    (1930),

Patent DE522884

  In German 
SO2Cl2 is prepd. from Cl and SO2 by the catalytic action of active C prepd. by the decompn. of carboniferous material by the aid of other catalyzers at temps. below 400°.  An example is given.

A laboratory process for the preparation of sulfuryl chloride.
Meyer, Julius.   
Z. angew. Chem.  (1931),  44  41-2. language unknown
Danneel's process, C. A. 21, 1235, for the combination of Cl2, and SO2 with activated C is simplified.  A ball condenser with 6 balls loosely packed with glass wool and granular C was used as the catalyst chamber.  To prevent initial gas loss the charge of the top ball was moistened with 1 cc. of liquid sulfuryl chloride.  The gases enter the reaction chamber through a H2SO4 wash bottle which serves also as a flow indicator. 150 g. of SO2Cl2 may be prepd. per hr. at a gas flow of 3-4 bubbles per sec.  Quant. combination ol the gases is obtained at temps. up to 20°.  The raw product is very pure and requires only 1 fractionation.  In contrast to the Danneel process, the advantages of the method lie in the simplified app., the use of a small quantity of activated C, and the lack of a need for low temp. 

Sulfuryl chloride.    
McKee, Ralph H.; Salls, Carroll M.    (1930),    
Cl gas and SO2 are passed into a body of sulfuryl chloride contg. a minor proportion of a catalyst such as an acid-treated active C in suspension.

Laboratory apparatus for the preparation of sulfuryl chloride.    
Danneel, H.    Z. angew. Chem.  (1926),  39  1553-4.  Journal  language unknown.   CAN 21:10237    AN 1927:10237   
Sulfuryl chloride is prepd. by passing equiv.  Proportions of Cl and SO2 through activated C in a 500-cc. tube provided with an overflow.  Rubber connections may be used.  As the reaction is strongly exothermic, it is necessary to cool in an ice-salt mixt.  A 100% yield may be obtained and a kg. prepd. in an hr.

The preparation of sulfuryl chloride.    
Durrans, T. H.   
J. Soc. Chem. Ind.  (1926),  45  347-50T. 
cf. C. A. 13, 1587.  Exptl. results indicate that only substances possessing residual affinity in some form are capable of catalyzing the reaction SO2 + Cl2 ® SO2Cl2, and that this function is exerted by forming simultaneously with both Cl2 and SO2 loose compds., which then proceed to interact to form SO2Cl2 and to regenerate the free catalyst.  As the reaction is bimol. the greatest velocity is attained when the concns. of the 2 loose compds. are equal; an excess of one of the gases tends progressively to sat. the catalyst at the expense of the other gas, thus inhibiting the final reaction by disturbing the equimol. ratio.  The following compds. were found to be good catalysts: EtOAc, Me2CHCO2Et, AcCH2CO2Et, PhCH2CO2Et, BzOEt, PhCH:CHCO2Et, CH2(CO2Et)2, iso-AmO2CH, iso-AmOAc, iso-AmONO2, PhCH2OAc, PhCH2OBz, PhCH2CN, PhOAc, CH(OAc)(CH2OAc)2, CH2(OH)CHClCH2Cl, Ph3PO4, (o-MeC6H4)3PO4, Et2O, (PhCh2)2O, p-MeC6H4OMe, BzH, Ac2CH2, (CH2)5:CO, AcPh, AmCH(OMe)2, eucalyptol, Me isoeugenol, anisaidehyde, a-pinene and limonene; the following catalysts were of more moderate activity: MeCH(OEt)2, iso-BuCl, Ph2CO, Me2CO, C6H6N and carvone;  the following were inactive or nearly so: BzOMe, iso-AmOBz, ClCH2CO2Me, Cl3CCO2Bu, Me2SO4, CH(OH)(CH2OH)2, BzOH, C2H7CO2H, ClCH2CO2H, Cl2CCO2H, PhCH:CHCO2H, o HOC6H4CO2H, PhCH2CO2H, C5H12, PhH, PhMe, PhNO2, BzCl, AcCl, CHCl3, CCl4, and oleic acid. 

DAMN If these guys did it with cork stoppers then anyone can do it!!

Preparation of sulfuryl chloride.
Bert, Leonce.   
Bull. soc. chim.  (1922),  31  1264-70.
For the prepn. of large amts. of SO2Cl2 the method of Ruff (Ber. 34, 3509 (1901)) is most practicable but it contains two sources of difficulty.  Cork stoppers, even protected by Na2SiO3, are soon disintegrated by hot vapors of SO3HCl and SO2Cl2 and the interior tube of a glass reflux is frequently fractured and entrance of water into the boiling SO3HCl causes violent and dangerous explosions.  These difficulties were overcome by covering the stoppers with several layers of asbestos paper cemented with Na2SiO3 (Vorlaender and Schilling, Ann. 310, 372(1900)) and by using for the inner tube of the reflux an iron tube of 1 m. interior diam., 1 m. length and 2 mm. wall-thickness, carefully scoured throughout the interior and so much of the exterior as projects into the flask.  The iron is attacked but little and salts of Fe have practically no influence on the reaction.  With a shorter tube the SO2Cl2 contains considerable SO3HCl and mercurous salt.  A condenser jacket 70 cm. long is placed as close as possible to the upper end of the iron tube.  The flask, of vol. 250 cc. for each 300 g. of SO3HCl heated, is fixed in an inclined position.  The condenser for SO2Cl2 is set vertically and connected to the top of the iron tube by a glass tube of 8 mm. exterior diam., as short as possible, by means of asbestos thread impregnated with Na2SiO3 at the iron and a Vorlaender stopper at the condenser.  Provided a rapid current of cold water was maintained in this condenser, various types proved equally efficient and cooling the receiver by ice was unnecessary.  After the entire app. has been carefully dried, the reflux jacket is filled with cold water and the tap closed; the SO3HCl is brought to rapid boiling and as soon as vapor of SO2O2 begins to appear in the second condenser, a very small stream of water is admitted to the first so as to maintain a temp. of 70-95°.  Use of 1% of HgSO4 instead of 0.66% Hg gave yields 4% greater; 56% in 2 hrs.; 80% in 6 hrs.  For greatest efficiency and economy, after heating 1 hr.
substitute a fresh flask of SO3HCl; let the first cool; HgSO4 seps. almost completely and is filtered off by glass wool and used again; recover SO3HCl by distn. and use the residual acid to generate HCl.  After rectification by a 60-cm.  Vigreux column the yield is 1500 g. of pure SO2Cl2 for each l200 g. of SO3HCl.  For prepn. of SO3HCl use com. oleum of 70% SO3, not over 1100 g. in a 1-1. flask, and displace air by HCl throughout the train before admitting the oleum.  Connect to the flask a 50-cm. condenser, glass or iron interior tube, by a glass tube of at least 8 mm. diam., bevelled at both ends and having a lateral opening near the bevel in the flask.  Satn. with HCl is evidenced by exit of this gas at the end of the train.  Then replace the inlet tube for HCl by a tube carrying a thermometer and distil.  An ordinary cork stopper easily endures distn. of 1 kg. of SO3HCl and the product is colorless.  Two kg. can be prepd. in 8 hrs. with a single app. 

The synthesis of sulfuryl chloride in the presence of organic compounds.  
Cusmano, G.    Florence,   
Gazz. chim. ital.  (1920),  50(II),  70-80.
It has long been known that HCO2H, AcOH, C2H4 and camphor favor the reaction SO2 + Cl2 ® SO2Cl2, which without them proceeds slowly in sunlight.  The C2H4 is chlorinated during the reaction and when this is complete SO2Cl2 ceases to be formed.  HCO2H and AcOH are also altered in the reaction but without definite relation to the production of SO2Cl2.  Camphor is not changed in the reaction.  In previous work C. (C. A. 13, 1587) found that other compds. have the same effect.  In extending this investigation C. has tested some other compds. and first detd. the influence of the CO group of camphor.  Thus dihydrocamphorone, cyclohexanone, tetrahydrocarvone, menthone and fenchone were tested; all of them behave like camphor.  When their halogen derivs. are used they lose this property.  Of the terpenic ketones, carvone, pulegone, and carvotanacetone were tested and found to favor the synthesis of SO2Cl2.  These compds. contain both an unsatd. linking and a CO group.  C.'s expts. have convinced him that of these the CO group is more active than the ethylene double bond.  AcMe does not promote the reaction, probably because it is so rapidly chlorinated.  This chlorination is so much diminished at -60° that AcMe now promotes the reaction.  MeCOEt behaves similarly while Me nonyl ketone is catalytically active even at -10°.  AcPh catalyzes the reaction at -10° but is chlorinated.  BzPh and fluorenone catalyze the reaction without being chlorinated but lose the power to do so if previously brominated or nitrated.  The monocarbonyl ketones accordingly have the property in general of increasing the velocity of combination of Cl with SO2 and lose this property when halogens, NO2 or SO3H groups are introduced at any distance from the CO (as tested with a-, b- and g-monobromocamphor).  The presence of CO2H does not interfere.  The influence of the chain bound to the CO does not appear to be great.  The 1st interpretation of the reaction offered and tested is that these compds. act through the basic property of their oxygen, i.
e., by the formation of unstable oxonium salts with the Cl or SO2 or both, and these salts are not formed when a negative atom or group is introduced, because this basicity is neutralized.  In order to test this hypothesis various other compds. were tested.  Cineo'e, which favors the reaction, undergoes chlorination as the Et ester, which had to be used at -45-50° in order to give good results.  Since the formation of oxonium derivs. is characteristic of O compds. aldehydes, acids and esters were tried.  Alcs. were excluded because of their ease of chlorination.  EtCHO gave good results at -50°.  BzH and piperonylic aldehyde even at -10° did not catalyze the reaction well.  Meta- and paraldehyde gave fair results at -10°.  AcOH and BzOH promote the reaction at -10° slowly.  BzOH is not chlorinated and is therefore the best.  AcOEt and BzOEt act, but must be protected from the Cl by working at -50°.  Of other compds. containing two O functions used, ketocineole and camphorcarboxylic acid promote the synthesis, while camphorquinone, buccocamphor, benzo- and thymoquinone are inert at -10°.  In the a,a-diketones the one CO acts as a negative group toward the other and if one is converted into an oxime the compd. becomes catalytically active; isonitrosocamphor acts like camphor.  With the quinones the inactivity is probably due to the formation of relatively stable addition products with Cl or SO2.  The inactivity of dibenzalacetone and similar compds. may be explained analogously.  The results are summarized in a large table.  The compds. were used in equimol. amts., treated with excess of SO2, reduced to a detd. temp. and treated for the same period of time at the same rate with SO2 and Cl2 dried with H2SO4.  The SO2 was expelled and the SO2Cl2 removed and detd. by distn., after which the residue was examd.  In only a few cases was the compd. used for catalysis recovered unchanged.  In most cases it was chlorinated.  Blank expts. showed whether this was due to the Cl or SO2Cl2 either during the synthesis or distn.
 C. thinks that a transitory compd. is formed of the oxonium type, but that not all compds. capable of giving these derivs. necessarily favor the reaction but only those that are formed and decompd. with a certain velocity.  The ketones and esters seem to have the required properties in the right degree.  The expts. are being continued. 

Investigation of the catalytic activity of charcoal in the synthesis of sulfuryl chloride.    
Soloniewicz, Rajmund.    Politech.,  Lodz,  Pol.   
Zeszyty Nauk. Politech. Lodz., Chem.  (1961),  10  85-9.  CAN 60:49341    AN 1964:49341
Charcoal "Carbopol extra" (made in Zaklady Elektrod Weglowych, Raciborz) was used as a catalyst in the synthesis of SO2Cl2 from SO2 and Cl2.  With this catalyst (dried at 200-250°) conversion of SO2 + Cl2 mixts. (in a molar ratio 1:1) can be up to 85.5%.  The activity of the catalyst does not change over 40 hrs. of operation.  Adsorption of H2O on charcoal surface causes poisoning of the catalyst. 

Those who give up essential liberties for temporary safety deserve neither liberty nor safety