I am in China and can obtain a large quantity of Ephedra. The situation is not optimistic regarding the extraction of ephedrine as follows:
I. Materials and ProportionsEphedra: 100 g (cut into small pieces)Distilled water: 2 × 500 mL (approximately 1000 mL total)1 mol/L Hydrochloric acid: about 100 mL10% NaOH solution: about 70–100 mL (for backup)Ethyl acetate: 3 × 100 mL (for each extraction)Anhydrous sodium sulfate: about 10 g (for drying)
II. Detailed StepsStep 1: Water extraction (heating with an induction cooker)Operation:Cut 100 g of dry Ephedra into 1–2 cm small pieces and place them in a stainless steel pot.Add 500 mL of distilled water.Set the induction cooker to medium heat (heat to about 95°C), maintaining a slight boil for 60 minutes.Filter with filter paper and collect the first batch of extract.Add another 500 mL of distilled water to the remaining herbal residue, and repeat the extraction for 40 minutes, then filter.Observation:Initially, the water is light yellow and has a herbal aroma;During the boiling process, the liquid gradually turns yellow-brown.Notes:Keep the liquid at a boil without vigorous rolling (to prevent spillage).Combine the two batches of liquid, with a final volume of about 900 mL.Step 2: Acidification (conversion to hydrochloride of ephedrine)Operation
our 900 mL of the extraction liquid into a glass beaker.While stirring, slowly add 1 mol/L hydrochloric acid, 5 mL at a time, and mix well with a glass rod.After every 10 mL added, test the pH with pH test paper until it reaches pH = 2–3.Observation:The liquid color changes from yellow-brown to clearer;Some impurities will precipitate.Notes:Add acid slowly to avoid local acidity being too high, which leads to significant precipitation.If there is precipitation, let it sit for 10 minutes, then filter and take the clear liquid.Step 3: Alkalization (precipitation of free ephedrine)Operation:Continue to keep the acidified filtrate (about 900 mL) in the beaker.Slowly add the 10% NaOH solution while stirring.Add 5 mL at a time and check the pH with test paper.Control the pH to 10–11.Observation:The liquid changes from clear to cloudy;A milky suspension will appear on the surface, which is free ephedrine.Notes:It is essential to stir sufficiently to prevent local alkalinity from becoming too high;Excess alkalization (pH > 12) will introduce impurities.Step 4: Extraction (Operation with a 1000 mL Separatory Funnel)Operational Stepsour the alkalized 900 mL solution into a 1000 mL separatory funnel.Add 100 mL of ethyl acetate, cover with a stopper, and shake vigorously for 1 minute, opening the stopper to release pressure every 10 seconds.Let it stand for 5 minutes to allow for stratification: the upper layer is the ethyl acetate layer (containing ephedrine), and the lower layer is the aqueous layer.Open the stopper, first release the lower aqueous layer, then collect the upper ethyl acetate layer.Repeat Extraction:Add another 100 mL of ethyl acetate, repeat the operation, extracting a total of 3 times.Combine all the ethyl acetate layers (approximately 300 mL).Observation:The ethyl acetate layer appears as a pale yellow transparent liquid;The aqueous layer remains cloudy.Notes:Release pressure promptly (ethyl acetate is slightly volatile and can generate pressure in the separatory funnel).Only release liquid when stratification is obvious to avoid emulsification.Step 5: Drying and EvaporationOperational Steps:Add 10 g of anhydrous sodium sulfate to the combined ethyl acetate layer, shake well, let it stand for 10 minutes, and then filter.Pour the dried ethyl acetate liquid into a glass beaker.Set the induction cooker to 50°C and use a water bath for heating (water in the pot + beaker suspended).Continue to evaporate the ethyl acetate until the solvent is completely volatilized.Observation:The ethyl acetate will gradually decrease, and crystals will precipitate on the surface of the liquid;Ultimately, yellow or pale white crystals/powder will be obtained, which is crude ephedrine.Notes:Ethyl acetate is flammable, so use the induction cooker at low temperatures to avoid sparks;It is recommended to perform the evaporation in a fume hood or outdoors.
I. Materials and ProportionsEphedra: 100 g (cut into small pieces)Distilled water: 2 × 500 mL (approximately 1000 mL total)1 mol/L Hydrochloric acid: about 100 mL10% NaOH solution: about 70–100 mL (for backup)Ethyl acetate: 3 × 100 mL (for each extraction)Anhydrous sodium sulfate: about 10 g (for drying)
II. Detailed StepsStep 1: Water extraction (heating with an induction cooker)Operation:Cut 100 g of dry Ephedra into 1–2 cm small pieces and place them in a stainless steel pot.Add 500 mL of distilled water.Set the induction cooker to medium heat (heat to about 95°C), maintaining a slight boil for 60 minutes.Filter with filter paper and collect the first batch of extract.Add another 500 mL of distilled water to the remaining herbal residue, and repeat the extraction for 40 minutes, then filter.Observation:Initially, the water is light yellow and has a herbal aroma;During the boiling process, the liquid gradually turns yellow-brown.Notes:Keep the liquid at a boil without vigorous rolling (to prevent spillage).Combine the two batches of liquid, with a final volume of about 900 mL.Step 2: Acidification (conversion to hydrochloride of ephedrine)Operationour 900 mL of the extraction liquid into a glass beaker.While stirring, slowly add 1 mol/L hydrochloric acid, 5 mL at a time, and mix well with a glass rod.After every 10 mL added, test the pH with pH test paper until it reaches pH = 2–3.Observation:The liquid color changes from yellow-brown to clearer;Some impurities will precipitate.Notes:Add acid slowly to avoid local acidity being too high, which leads to significant precipitation.If there is precipitation, let it sit for 10 minutes, then filter and take the clear liquid.Step 3: Alkalization (precipitation of free ephedrine)Operation:Continue to keep the acidified filtrate (about 900 mL) in the beaker.Slowly add the 10% NaOH solution while stirring.Add 5 mL at a time and check the pH with test paper.Control the pH to 10–11.Observation:The liquid changes from clear to cloudy;A milky suspension will appear on the surface, which is free ephedrine.Notes:It is essential to stir sufficiently to prevent local alkalinity from becoming too high;Excess alkalization (pH > 12) will introduce impurities.Step 4: Extraction (Operation with a 1000 mL Separatory Funnel)Operational Stepsour the alkalized 900 mL solution into a 1000 mL separatory funnel.Add 100 mL of ethyl acetate, cover with a stopper, and shake vigorously for 1 minute, opening the stopper to release pressure every 10 seconds.Let it stand for 5 minutes to allow for stratification: the upper layer is the ethyl acetate layer (containing ephedrine), and the lower layer is the aqueous layer.Open the stopper, first release the lower aqueous layer, then collect the upper ethyl acetate layer.Repeat Extraction:Add another 100 mL of ethyl acetate, repeat the operation, extracting a total of 3 times.Combine all the ethyl acetate layers (approximately 300 mL).Observation:The ethyl acetate layer appears as a pale yellow transparent liquid;The aqueous layer remains cloudy.Notes:Release pressure promptly (ethyl acetate is slightly volatile and can generate pressure in the separatory funnel).Only release liquid when stratification is obvious to avoid emulsification.Step 5: Drying and EvaporationOperational Steps:Add 10 g of anhydrous sodium sulfate to the combined ethyl acetate layer, shake well, let it stand for 10 minutes, and then filter.Pour the dried ethyl acetate liquid into a glass beaker.Set the induction cooker to 50°C and use a water bath for heating (water in the pot + beaker suspended).Continue to evaporate the ethyl acetate until the solvent is completely volatilized.Observation:The ethyl acetate will gradually decrease, and crystals will precipitate on the surface of the liquid;Ultimately, yellow or pale white crystals/powder will be obtained, which is crude ephedrine.Notes:Ethyl acetate is flammable, so use the induction cooker at low temperatures to avoid sparks;It is recommended to perform the evaporation in a fume hood or outdoors.