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 (
– practice is a great teacher
), 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 lungs
(– 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!
) 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 bedroom
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 DCM
), 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!
He has seen this fucken dream not less than six times beefore! This was the 1st to end well
…
Oh my dear fellow beez!
Antoncho