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Zanima me sinteza zgoraj napisanih kemikalij.

Našel sem eno sintezo, ampak končaš z zmesjo o-/p-nitroanilina, ker pri nitriranju acetanilida nastane tako o- kot p-nitroacetanilid.

Acetanilide: Measure 5.0 g of aniline into a 125-mL Erlenmeyer flask. Add 40 mL of water to the flask. Stir the contents while adding 6.5 mL of acetic anhydride. After the addition, stir for an additional 10 min and then vacuum filter the product. Spread the solid out on a large piece of filter paper in a petrie dish to dry quickly. Save a little for characterization and use the rest in the next step.

p-Nitroacetanilide: Add 3.0 g of acetanilide to 5 mL glacial acetic acid in a 25-mL Erlenmeyer flask. Carefully pour 5 mL concentrated sulfuric acid into the mixture while stirring constantly. After the acetanilide has dissolved, place the flask in an ice-salt bath and cool it to 5 ºC. Prepare a solution of 2 mL concentrated nitric acid and 1.3 mL concentrated sulfuric acid. While stirring the acetanilide solution, add dropwise the nitric/sulfuric mixture at a rate such that the temperature does not rise over 20 ºC. After the addition, let the mixture stand at room temperature for 20 min. Pour the reaction mixture into 25 mL of cold water with 15 g of ice. Collect the solid that forms by vacuum filtration and wash the solid with three 30-mL portions of cold water. Recrystallize the solid from 95% ethanol and characterize it.

p-Nitroaniline: Add 2.2 g of p-nitroacetanilide and 5 mL of water to a 25 mL round bottom flask. Slowly add 5 mL concentrated sulfuric acid while swirling. Reflux the mixture for 30 min. Cool the reaction mixture and pour the contents into a mixture of 15 g ice in 20 mL water. Slowly with stirring add 9 M sodium hydroxide until the pH of the mixture reaches 4-5. Cool the mixture in an ice bath and collect the precipitate by vacuum filtration. Wash the solid four times with 20 mL portions of water.

Literatura:Mohrig, J.R.; Morrill, T.C.; Hammond, C.N.; Neckers, D.C. Experimental Organic Chemistry; Freeman: New York, NY, 1997; pp 456-467

Uh.. Ful hvala, nikjer nisem našel te sinteze. Edin problem je anhidrid ocetne kisline, ki ga žal nimam, imam pa 100% ocetno kislino, vendar spet nimam P4O10 da bi naredil anhidrid.

Maš mogoče še kakšen postopek kako naredit nitrosalicilno kislino(katero koli).

Bom poiskal. A mi hočeš samo povedat, za kaj se to rabi (nitrosalicilna kislina oz. nitroanilin). Saj te nitracije potekajo vse po standardnem postopku HNO3/H2SO4. Fora je samo v tem ali imaš na aromatski obroč vezane elektron donorske (usmerjajo nitracijo na o-/p-) ali el. akceptorske skupine (usmerjajo na m- mesto).

Nitrosalicilno kislino bom uporabil med drugim tudi za dokaz FeCl3. Drugač pa me zanima sinteza sama po sebi.

Nisem našel nič. Ti kar uporabi to metodo HNO3/H2SO4 za nitriranje pa boš dobil 3- in 5-nitrosalicilno kislino.

Naj ti odgovorim še na nekaj iz posta o nitroanilinu. Ker si rekel da nimaš acetanhidrida, lahko acetiliraš aminsko skupino tudi z acetilkloridom. P4O10 ti ne bo iz ocetne kisline naredil anhidrida. Lahko pa probaš nitrirat tudi brez zaščite aminske skupine z acetiliranjem, ampak se ti bo verjetno oksidirala do neke mere.

kolikor jaz vem se da amine acetilirati tudi samo z koncentrirano ocetno kislino, vendar pa je potrebna malce višja temperatura, tako da iz reakcijew izstopa odvečna H2O z nekaj kisline...

Imaš kakšne reference za to reakcijo. Drugače ni nujno, da se zaščiti aminsko skupino ravno z acetiliranjem. Veliko drugih načinov za zaščito aminske skupine lahko najdeš s pomočjo googla, samo paziti moraš, da izbereš tako zaščitno skupino, da nanjo oksidacija (v tem primeru) ne vpliva in da se zaščitne skupine lahko na koncu enostavno znebiš.

Citiram:

Making N-acetyl-ortho-toluidine:

Using Acetic Anhydride:

You don't need much of a reflux column; you can use a 400mm condenser attached to a 500ml round bottomed flask. Put in 50ml of o-toluidine and add 50ml of acetic anhydride through the condenser, there will be an immediate reaction and the solution will begin to boil. The fluids only condense up about 2cm into the condenser so the one I suggested is overkill. Using a small flame, continue the boil for about 8 or 9 minutes and then dump the contents directly into a 1 liter flask filled to 900ml with room temperature dH2O. Pink crystals will immediately form. Cool the solution in the freezer until cold, but don't freeze and then filter the crystals with suction and save the mother liquid. Using gentle heat from a lamp dry the crystals and recrystalize by using just enough boiling hot alcohol to dissolve them and cooling the alcohol in a freezer for 15-20 minutes. Vacuum filter the recrystalized product from the solution and save the solution in the same flask as the first filtration thereby saving all the liquid.

After about an hour the mother liquid will have formed crystals also. Filter this and combine with the first product, you should probably wait a couple of hours to make sure it has all crystalized. Yield was 43 grams of white needle like crystals.

Using Glacial Acetic Acid:

The above is the easiest of the methods to date, but suppose you can't get acetic anhydride? If this is the case, get glacial acetic acid. Yep, this is just concentrated vinegar! Follow the above instructions, but use 100ml of glacial acetic instead of the acetic anhydride and reflux for three hours; your results will be the same. The glacial acetic will not boil on addition, just warm up a little. Oh, another advantage of glacial acetic acid is, this stuff costs around US$12.00 a gallon. This is a cheaper method by far.

Possible screwups:

You added the acetic anhydride too fast and it bubbled back up the condenser and burned your hand. Run cold water over your hand count your blessings that it didn't get your eyes and continue with whatever reagents you have left.

You left it too long in the freezer and the expanding ice broke the flask and you have icicles all over the place. Gather as much of it together as you can, thaw and proceed. You can blame the low yield on "non reagent grade chemicals."

Acetiliranje je sigurno najbolj enostavna zaščita... Amin in ocetna kislina najprej tvorita sol, ki se pri segrevanju in odstranjevanju (azeotropnem?) vode dehidrira do amida... Pomojem da je reakcija za anilin zelo podobna kot z toluidinom (samo ena metil skupina več)

mnogo aminov se da acetilirat tudi z etil acetatom (transestrifikacija)...

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