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Author: Subject: 2-ethoxynaphthalene = 2-naphthol ethyl ether = Nerolin II
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[*] posted on 4-8-2022 at 06:44
2-ethoxynaphthalene = 2-naphthol ethyl ether = Nerolin II


reference - ethylation of acetaminophen to phenacetin The-Synthesis-of-Phenacetin-from-Acetaminophen.pdf
https://people.chem.umass.edu/mcdaniel/CHEM-268/Experiments/...

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calculations:

M(2-naphthol) = 144,17 g/mol
M(K2CO3) = 138,21 g/mol
M(C2H5I) = 155,97 g/mol

36,0 g 2-naphthol (0,25 mol)
34,6 g K2CO3 (0,25 mol) but excess 50,0 g used which does not hurt - predried by heating in crucible at 300 C for half an hour
39,0 g C2H5I (0,25 mol)
300 ml 2-butanone density 0,805 g/ml = 241,5 g

pre-experiment preparation:
K2CO3 was dried in a nickel crucible with a lid at 300 C for 30 minutes in 2 batches, weight loss of the K2CO3 in first batch was from 42,6 g to 35,0 g (the K2CO3 used was a K2CO3.xH2O hydrate).

experiment itself:
Into 1 L 2-neck RBF equipped with reflux Liebig condenser and 100 ml dropping funnel there was added :
36,0 g 2-naphthol,
50,0 g K2CO3 (big excess circa 50%, cheap, does not hurt, dries possible traces of water in the solvent),
300 ml methylethylketone,
magnetic stirbar.
The content was refluxed on oil bath and magnetically stirred to dissolve as much of 2-naphthol as possible (C10H7OH + K2CO3 -> C10H7OK + KHCO3), not all K2CO3 dissolved, that's OK. Then cooled down to circa 50 C.
39,0 g C2H5I was charged into dropping funnel and dropped into reaction during 15 minutes while stirring. A pipette had to be used to transfer it due to its extremely low viscosity and very high volatility (little of was inevitably spilled by pouring it off the reagent flask on a glass rod, it escaped on the outer surface of the reagent flask even the flask had specially designed neck to prevent escaping on pouring).
Then refluxed and magnetically stirred for 1 hour.
Reflux condenser rearranged into downward distillation condenser and 250 ml of MEK from original 300 ml distilled out on oil bath and magnetic stirring, especially slowly and with careful heating near the end.
200 ml of warm water added into the flask and magnetically stirred - all inorganic salts dissolved. The product separated in upper layer.
Transferred into in 500 ml separatory funnel, upper organic layer kept and bottom aqueous discarded.
Washed with warm 200 ml of 2% NaOH, then washed 5 times with 200 ml of warm water until the scent of MEK gone, now the product in bottom layer.
Hydrodistilled (lazy simple distillation) on flame burner and boiling stones using the same flask as for reaction. Circa 1,5 L distillate collected, after which no product in the condenser anymore. Distillate gravity filtered and water reused into hydrodistillation after discarding first 100 ml of water (MEK scent).

yield 27,8 g
it has more orange scent than 2-methoxynaphthalene

??? Maybe acetone could work too, but it has lower b.p. (acetone 56 C, MEK 79,6 C) so the reaction would run slower (23,6 C difference = 5x slower reaction).



reagents and predrying K2CO3 (it lost a lot of water)

IMG_20220802_152844_8.jpg - 33kB IMG_20220802_110400_4.jpg - 23kB



2-naphthol + K2CO3 + MEK, refluxing it

IMG_20220802_160006_2.jpg - 14kB IMG_20220802_160610_2.jpg - 34kB



C2H5I charged into dropping funnel, dropped into reaction, refluxing reaction

IMG_20220802_162741_1.jpg - 33kB IMG_20220802_171948_6.jpg - 22kB IMG_20220802_181524_8.jpg - 23kB



distilling off most of MEK was not captured on photos



after removing most of MEK and added H2O into reaction to dissolve inorganic salts, organic layer in upper phase

IMG_20220802_195626_8.jpg - 29kB



washing with warm water in separatory funnel (thermally insulated with newspapers), the product in bottom layer (organic product lost MEK and water phases decreased density because of purer water without inorganic salts), note the droplets of organic phase never connected and stayed dispersed in water

IMG_20220803_050414_1.jpg - 36kB IMG_20220803_062335_9.jpg - 35kB IMG_20220803_063912_6.jpg - 18kB



hydrodistillation of the product, reusing water after gravity filtration (through dropping funnel back into distillation flask)

IMG_20220803_105534_1.jpg - 37kB IMG_20220803_111349_9.jpg - 20kB IMG_20220803_112012_8.jpg - 25kB



carefully watching condenser not to clog it, warm water melted the product which slid into receiving beaker

IMG_20220803_134231_4.jpg - 28kB IMG_20220803_134253_8.jpg - 29kB



the product

IMG_20220803_163309_7.jpg - 39kB IMG_20220803_174235_4.jpg - 28kB




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