ty vm for suggestion, but you cannot answer me instead of I would answer your questions if I would understand them. Instead of asking
a question, all you do is asking a lot of useless questions and questioning the answers when there is no need for it. Besides, if you wanted instructions on how to concentrate H2SO4 and make tosic acid why didn’t you post in the Newbee forum? More people with experience on this would bee able to take some time and answer. What exactly is your main question? Instead for asking for tips and instructions all you do is question the well established preparation of TsOH×H2O and loosing time with what you could readily found out by yourself with an excursion to the library. Like here, look:
why ? toluene wont form an azeotrope with the water ?
ptsa wont be vapourized ?
in fact i just want to know:
in the water trap, i will get some toluene and a few water ? or will i only get some water?
and finally: thinking about just stirring the ptsa monohydrate-toluene with 5grams MgSO4 is stupid ?
- Toluene and most water inmishelable solvents form azeotropes (benzene, hexane, CHCl3 etc.).
- Tosic acid does not evaporate and why should it?
- In a Dean-Stark trap you will get water at its bottom (water has higher density than toluene - this is why this trap works).
- Trying to dry a hydrate by forming another hydrate is not feasible. MgSO4 does bind water, but so does TsOH, meaning that even if TsOH×H2O would give up some water it would never give up
all the water (thermodynamic equilibriums). This is not really a feasible way to get anhydrous tosic acid.
OK enough, I guess you don't need pure tosic acid, so this will do:
Follow the usual procedure for the sulphonation of toluene (like described in Organikum or whatever other preparative book). At the end of the reflux (with a Dean-Stark trap!) separate the toluene layer while still relatively hot (>60°C) so that no tosic acid crystallizes out. This is best done simply decanting the above layer off. Then distill this toluene fraction, reuse the distilled toluene to extract the remaining black H2SO4 phase by heating and mixing them for a few minutes. Decant again in the distilling flask and repeat. Doing this three or four time should bee enough. In the distillation flask you will bee left with brown tosic acid contaminated with some toluene, o-toluenesulphonic acid, H2SO4 and other stuff. This waxy stuff will solidify on cooling. This product is very crude and dirty but it will do just fine for most uses. If you took care to cleanly separate the toluene fractions from the black sulphuric acid fraction, you might bee lucky and see the TsOH crystallize.
This was checked and is as simple as it can bee done.
so close to succeed!!!!!!!!!!!!Yeah, and don’t forget the damn boiling chips again or you will end up in an emergency room with your face unrecognizable from hot sulphuric acid burns! No serious chemist ever forgets boiling chips, not even if he is distilling water.