Hi bb
Im unsure about this recipe ive got if someone could look over it, are weights correct? is the process correct? any helpful suggestions would be greatly appreciated.
Preparation of (psuedo) Ephedrine (dl and l forms)
Purity of Ingredients
51 mls of Benzaldehyde 99.98%
33 mls of nitroethane 99.8%
30 mls of 30% potassium carbonate solution 99.5%
650 mls of diethyl ether 99.7%
90 mls of a 10% sodium bisulfite solution 100%
30 gms of anhydrous magnesium sulfate - 24.305 g/mol magnesium =28.5% 96 g/mol sulphate =71.5%
19 mls of 37% formaldehyde 37%
6 gms grams of zinc dust ? 100%
20 mls of a 45% acetic acid solution 99%
6 gms of hydrogen sulfide gas ? - 2*1 g/mol H2 + 32 g / mol S = 34 g/mol H2S so 4.5% h2 and 95.5% s, so for 6gms of h2s 0.27gms are h2 (hydrogen), and 5.73gms are s (sulphur)
11 mls of 32% hydrochloric acid 32%
15 mls of a 40% anhydrous sodium carbonate solution 100%
Summary:
In this process, ephedrine is prepared by the condensation of benzaldehyde with nitroethane in the presence of potassium carbonate, then the mixture is treated with ether and then a solution of sodium bisulfite which removes any unreacted benzaldehyde, the ether layer is recovered, washed and then dried and the resulting ether mixture then evaporated to recover the intermediate product, phenylnitropropanol.
This phenylnitropropanol is then reduced by reacting it with formaldehyde in the presence of acetic acid and zinc dust. After the reduction the reaction mixture is treated with hydrogen sulfide gas to precipitate any dissolved zinc, the resulting mixture is then filtered and treated with ether followed by hydrochloric acid. The ether layer is then removed and the aqueous layer is then treated with sodium carbonate to liberate the freebase of ephedrine. The freebase is then extracted into ether, the ether layer is then recovered and dried, then evaporated or treated with hydrogen chloride gas to obtain the hydrochloride.
Preparation of phenylnitropropanol:
Into a suitable beaker or conical flask place 51mls of benzaldehyde, followed by 33mls of nitroethane, immediately thereafter add in 30 mls of a 30% potassium carbonate solution, rapidly stir the entire mixture at room temperature for 2 hrs.
A cold water bath or ice bath may be needed to keep the reaction mixture at ambient temperature (room temperature) or below. Do not allow the reaction mixture to get above 25 degrees celsius.
After stirring for 2 hrs add to the reaction mixture 200mls of diethyl ether, shortly thereafter add in 90mls of a 10% sodium bisulfite solution and moderately stir the entire reaction mixture for 30 minutes.
Afterwards place the entire reaction mixture into a seperatory funnel and remove the lower aqueous layer, leave the ether layer in the seperatory funnel and wash the ether layer with 3 x 75ml portions of cold water, each time removing the lower aqueous layer.
Place the ether layer into a suitable beaker or conical flask and add 15gms of anhydrous magnesium sulfate and stir the entire mixture for 10 minutes to absorb any water in the ether. Then filter off the magnesium sulfate.
Place the filtered ether mixture into a distallation apparatus and remove the ether, when no more ether passes over or is collected allow the residue to cool to room temperature, then collect this residue as it consists of the desired phenylnitropropanol.
Reduction of phenylnitropropanol to ephedrine:
Place a suitable flask equipped with motorized stirrer into an ice bath and add to it 15gms of phenynitropropanol, chill the phenylnitropropanol to 0 degrees celsius and then add in 19mls of 37% formaldehyde, begin to stir these contents vigorously and then carefully add in 20mls of a 45% acetic acid solution, do this in additions and don’t let the reaction mixture get above 5 degrees celsius. Once all the acid solution is in then start to add in portions a total of 6 gms of zinc dust, always making sure to keep the reaction mixture below 5 degrees celsius.
Continue to stir the reaction mixture below 5 degrees celsius for about 90 minutes to complete the reaction. Then stop stirring and filter off any insoluble zinc or other materials.
Place the filtered reaction mixture back into the ice bath and bubble 6 gms of hydrogen sulfide gas into it while stirring the reaction mixture vigorously or moderately. The hydrogen sulfide gas will precipetate any dissolved zinc in the reaction mixture.
Then filter the reaction mixture to remove the zinc and any other insoluble materials. Wash the flask with a small measured amount of water and filter this aswell.
Add to the mixture 250mls of cold water, deducting the small measured amount used to wash the flask, Then add 150mls of ether followed by 11mls of 32% hydrochloric acid, vigorously stir the entire mixture for about 1 hr.
After 1 hr place the entire reaction mixture into a seperatory funnel and remove the lower water layer which will contain the desired ephedrine product as the hydrochloride. Remove the ether layer and recycle for next time.
To the recovered water layer add in 15ml of a 40% sodium carbonate solution and stir the mixture for about 15 minutes. Then extract this entire mixture with 3 x 100ml portions of ether using a seperation
funnel, Then combine the ether portions and add 15gms of anhydrous magnesium sulfate and stir the mixture for 10 minutes, Then filter off the magnesium sulfate.
Then place the filtered ether mixture into a distillation apparatus and remove the ether until a total volume of 80% has been reduced. The resulting ether concentrate can then be filtered to recover the product and then vacuum dried or placed into a crystallizing dish set on a low heat (no more than 25 degrees celsius) with a fan gently blowing across the top of the dish to speed the evaporation of the remaining ether. Once the ether is removed the product should crystallize in the dish, recover the product, weigh, record the results and store in an appropriate amber glass bottle.
Im unsure about this recipe ive got if someone could look over it, are weights correct? is the process correct? any helpful suggestions would be greatly appreciated.
Preparation of (psuedo) Ephedrine (dl and l forms)
Purity of Ingredients
51 mls of Benzaldehyde 99.98%
33 mls of nitroethane 99.8%
30 mls of 30% potassium carbonate solution 99.5%
650 mls of diethyl ether 99.7%
90 mls of a 10% sodium bisulfite solution 100%
30 gms of anhydrous magnesium sulfate - 24.305 g/mol magnesium =28.5% 96 g/mol sulphate =71.5%
19 mls of 37% formaldehyde 37%
6 gms grams of zinc dust ? 100%
20 mls of a 45% acetic acid solution 99%
6 gms of hydrogen sulfide gas ? - 2*1 g/mol H2 + 32 g / mol S = 34 g/mol H2S so 4.5% h2 and 95.5% s, so for 6gms of h2s 0.27gms are h2 (hydrogen), and 5.73gms are s (sulphur)
11 mls of 32% hydrochloric acid 32%
15 mls of a 40% anhydrous sodium carbonate solution 100%
Summary:
In this process, ephedrine is prepared by the condensation of benzaldehyde with nitroethane in the presence of potassium carbonate, then the mixture is treated with ether and then a solution of sodium bisulfite which removes any unreacted benzaldehyde, the ether layer is recovered, washed and then dried and the resulting ether mixture then evaporated to recover the intermediate product, phenylnitropropanol.
This phenylnitropropanol is then reduced by reacting it with formaldehyde in the presence of acetic acid and zinc dust. After the reduction the reaction mixture is treated with hydrogen sulfide gas to precipitate any dissolved zinc, the resulting mixture is then filtered and treated with ether followed by hydrochloric acid. The ether layer is then removed and the aqueous layer is then treated with sodium carbonate to liberate the freebase of ephedrine. The freebase is then extracted into ether, the ether layer is then recovered and dried, then evaporated or treated with hydrogen chloride gas to obtain the hydrochloride.
Preparation of phenylnitropropanol:
Into a suitable beaker or conical flask place 51mls of benzaldehyde, followed by 33mls of nitroethane, immediately thereafter add in 30 mls of a 30% potassium carbonate solution, rapidly stir the entire mixture at room temperature for 2 hrs.
A cold water bath or ice bath may be needed to keep the reaction mixture at ambient temperature (room temperature) or below. Do not allow the reaction mixture to get above 25 degrees celsius.
After stirring for 2 hrs add to the reaction mixture 200mls of diethyl ether, shortly thereafter add in 90mls of a 10% sodium bisulfite solution and moderately stir the entire reaction mixture for 30 minutes.
Afterwards place the entire reaction mixture into a seperatory funnel and remove the lower aqueous layer, leave the ether layer in the seperatory funnel and wash the ether layer with 3 x 75ml portions of cold water, each time removing the lower aqueous layer.
Place the ether layer into a suitable beaker or conical flask and add 15gms of anhydrous magnesium sulfate and stir the entire mixture for 10 minutes to absorb any water in the ether. Then filter off the magnesium sulfate.
Place the filtered ether mixture into a distallation apparatus and remove the ether, when no more ether passes over or is collected allow the residue to cool to room temperature, then collect this residue as it consists of the desired phenylnitropropanol.
Reduction of phenylnitropropanol to ephedrine:
Place a suitable flask equipped with motorized stirrer into an ice bath and add to it 15gms of phenynitropropanol, chill the phenylnitropropanol to 0 degrees celsius and then add in 19mls of 37% formaldehyde, begin to stir these contents vigorously and then carefully add in 20mls of a 45% acetic acid solution, do this in additions and don’t let the reaction mixture get above 5 degrees celsius. Once all the acid solution is in then start to add in portions a total of 6 gms of zinc dust, always making sure to keep the reaction mixture below 5 degrees celsius.
Continue to stir the reaction mixture below 5 degrees celsius for about 90 minutes to complete the reaction. Then stop stirring and filter off any insoluble zinc or other materials.
Place the filtered reaction mixture back into the ice bath and bubble 6 gms of hydrogen sulfide gas into it while stirring the reaction mixture vigorously or moderately. The hydrogen sulfide gas will precipetate any dissolved zinc in the reaction mixture.
Then filter the reaction mixture to remove the zinc and any other insoluble materials. Wash the flask with a small measured amount of water and filter this aswell.
Add to the mixture 250mls of cold water, deducting the small measured amount used to wash the flask, Then add 150mls of ether followed by 11mls of 32% hydrochloric acid, vigorously stir the entire mixture for about 1 hr.
After 1 hr place the entire reaction mixture into a seperatory funnel and remove the lower water layer which will contain the desired ephedrine product as the hydrochloride. Remove the ether layer and recycle for next time.
To the recovered water layer add in 15ml of a 40% sodium carbonate solution and stir the mixture for about 15 minutes. Then extract this entire mixture with 3 x 100ml portions of ether using a seperation
funnel, Then combine the ether portions and add 15gms of anhydrous magnesium sulfate and stir the mixture for 10 minutes, Then filter off the magnesium sulfate.
Then place the filtered ether mixture into a distillation apparatus and remove the ether until a total volume of 80% has been reduced. The resulting ether concentrate can then be filtered to recover the product and then vacuum dried or placed into a crystallizing dish set on a low heat (no more than 25 degrees celsius) with a fan gently blowing across the top of the dish to speed the evaporation of the remaining ether. Once the ether is removed the product should crystallize in the dish, recover the product, weigh, record the results and store in an appropriate amber glass bottle.
I'll scrutinize it for a minute