CHEM 235 Lecture Notes - Lecture 6: Ground Glass Joint, Boiling Chip, Petroleum Ether

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champagnehare429

3 Dec 2016

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Need suction trap, 125 ml filter flask, filter vac, buchner funnel, small filter paper, glass rod with rubber tip, spatula, watch glass, solution. Use 3 pronged clamp to attach the suction flask with the vertical rod. Attach tube from suction trap to suction flask. Add filter vac, buchner funnel and a filter paper on the suction flask. Wet filter paper with a bit of cold solvent. Attach the tube to the aspirator and turn on full. Unmount the tube before pouring the solution in s. f, use the glass rod to hold still the filter paper. Reattach the tube, press down filter vac, use rubber tip to scrape out solvent or use the mother liquor to rinse it out. Use the suction to air dry the crystal for few mins: use the spatula to take out the filter paper with crystals on the watch glass, let it dry and cover.

Related Questions

Preparation of acetyl salicyclic acid (Aspirin) post-lab questions

1.)At the end of the reaction, you were asked to add ice-cold water to the reaction mixture. What do you think is the reason for this? Explain with chemical equations.

2.)How would the % yield of aspirin be changed if the final rinse of the solid product on the filter paper was done with warm water instead of ice-cold water?

3.)If you run a thin-layer chromatography for a mixture containing salicylic acid and aspirin using a 1:1 solvent mixture of ethyl acetate and hexane, which compound do you think would have more R_f value. Explain why? Bring in the structural features in your explanation.

summary Procedure of lab we did:

- Place approximately 0.300 g of salicylic acid in a tared empty 5 mL conical reaction vial. Record the actual weight of salicylic acid used. Using automatic pipet, add 0.8 mL of acetic anhydride (acetic anhydride vapors are very irritating-handle it carefully, in the hood). Add 2-3 drops of concentrated sulfuric acid using a dropper.

-Clamp the assembly so that the vial is partially submerged in the hot water. Turn on the magnetic stirrer. Once the water bath starts boiling, start timing the reaction. When the mixture has been allowed to react at 100 oC (the temperature of boiling water) for 15 minutes, you can consider the reaction to be complete. During the heating time, take about 20 mL of deionized water in a flask and chill it in an ice-water bath.

- After the reaction has gone on for 15 minutes, add very cautiously, drop by drop, 1 mL of deionized water to the reaction vial. At this point you should have a solution in your reaction vial. Remove the reaction vial form the hot water bath, add another 1-2 mL of DI water and let it stand at room temperature for few minutes. Then, detach the air condenser carefully and remove spin vane with forceps. Place the vial in a beaker and cool down to RT. During this time, the aspirin may begin crystallizing. If not, scratch the walls of the vial with a glass rod. Then, cool the vial in an ice-water bath.

- When the vial appears full of crystals, add about 3-4 mL of ice-cold DI water. Filter the aspirin using vacuum filtration (use Hirsch funnel). Leave the filtration setup in place for few minutes-this will draw air through the sample and will help dry aspirin.

Recrystallization of Aspirin:

- Transfer the rest of the crude aspirin to a 25 mL Erlenmeyer flask and do recrystallization using ethanol.

Purity of Aspirin:

- Using the melting point apparatus, determine the melting point of your crude aspirin and the recrystallized aspirin.

- To do FeCl3 test, get 4 test tubes. Place 1 mL of ethanol and 2 drops of 1% FeCl3 solution in each test tube. Add few crystals of salicylic acid to one test tube. Add few crystals of your crude aspirin product to the second test tube. In the thirst test tube, place a few crystals of your recrystallized aspirin. The fourth test tube will be your âblankâ. Shake each of the test tubes and record your observations.

Hello, I need help answering the questions for this experiment, please.

Part A: Microscale Hydration of 2-Ethyl-1-butene Add 2.5 mL of water to a 10-mL round-bottom flask containing a stir bar. Place the flask in a heat block or sand bath at room temperature and carefully add 0.64 g of mercuric acetate with stirring. Stir the mixture until the solid has dissolved. Add 1.0 mL of diethyl ether. Attach a reflux condenser to the flask and adjust the flow of cold water through the condenser. Using a calibrated pipet, measure out 290 Î¼L of 2-ethyl-1- butene in a conical vial and add 1.0 mL of diethyl ether. Use a Pasteur pipet to transfer this solution in small portions to the stirred aqueous solution down through the con- denser. Stir vigorously for 45 minutes. Remove the condenser. Add 1.0 mL of 6 M NaOH to the mixture using a Pasteur pipet, followed by a solution of 0.50 g of sodium borohydride in 2.0 mL of 3 M NaOH. Stir the mixture vigorously for 15 minutes. A mercury precipitate should form at the bottom of the flask. Remove the apparatus from the heat block or sand bath and remove the condenser. Allow the precipitate to settle. Use a Pasteur filter pipet to transfer the supernatant liquid (both layers) to a centrifuge tube. Set aside the mercury and mercuric salts for proper disposal. Transfer the lower aque- ous layer to a second centrifuge tube. Place the diethyl ether layer in a 5-mL conical vial. Add 1 mL of diethyl ether to the aqueous solution in the centrifuge tube. Cap and swirl gen- tly. Carefully remove most of the ether layer and add it to the ether solution in the conical vial. Repeat the extraction with a second portion of 1 mL of diethyl ether. Add the ether layer to the ether solution in the conical vial and add a small portion of anhydrous sodium sulfate. After a few minutes use a Pasteur filter pipet to transfer the solution to a tared 5-mL conical vial containing a boiling chip. If doing IR characterization (below), put a few drops on a salt plate and run the IR spectrum now. Evaporate the diethyl ether using a heat block, a sand bath, or water bath (40â45Â°C). Weigh the vial to determine the weight of the prod-uct. Keep the vial capped during analysis because the product is volatile.

Characterization for Part A Gas-liquid Chromatography: Using a 10-Î¼L syringe, remove a 1-Î¼L aliquot and inject it onto a moderately polar or polar GC column. One or more peaks may be recorded on the chromatogram including a peak for any remaining solvent and peaks for any remaining starting material and product(s). Authentic samples of potential products (if available) and starting material should be used as standards. Refractive Index: Use a few drops of product to determine the refractive index and apply the appropriate temperature correction. 3-Methyl-3-pentanol has an RI (nD) of 1.419020, and 2-ethyl-1-butanol has an RI (nD) of 1.422020. Infrared Spectroscopy (optional): Transfer 2â3 drops of the diethyl ether solution con- taining the product(s) to a salt plate, and press a second plate against the first to spread out the liquid. Remove the plates from one another briefly and press together a second time. The liquid remaining should now be free or nearly free of diethyl ether. Obtain the IR spec- trum. Compare the spectrum to authentic 3-methyl-3-propanol (a tertiary alcohol) and 2- ethyl-1-butanol (a primary alcohol). 3-Methyl-3-pentanol shows strong C O absorption at 1380, 970, and 900 cmâ1; these bands are not present in 2-ethyl-1-butanol.

Results and Conclusions for Part A

1. Identify each of the peaks by comparison of GC retention times of observed peaks with standards.

2. Measure the areas of the peaks in the chromatogram to calculate the mass percent. The correction factors for the alcohol and the starting alkene are approximately equal.

3. Determine the extent of conversion of 2-ethyl-1-butene to alcohol.

4. Write a detailed mechanism for the formation of the observed product(s). 5. Using your mechanism from above, explain the predominance of the observed product.

used 0.113g of CuCl, 1.0ml 95% ethanol, 1.0ml 2-methyl-3butyn-2-ol, 0.51ml NH4OH, 0.50ml concentrated hydrochloric acid, 2.5ml NaCl, 5ml MTBE, 2.7ml NaCl

Organic Chemistry I Lab-Chem. 322 A Greener Glaser II: Oxidative Coupling of Alkynes: 2,7-Dimethyl-3,5-octadiyn-2,7-diol er Glaser Il: Oxidative Coupling of Alkynes: 2,7-Dimethyl-3,5-octadiyn-27-diol ã¢q pa25 mL filtering flask with a magnetic stirring bar and arm and secured with a small rubber band: (Practice placing a 19/22 white rubber septum tne tlask, folding the top of the septun down and over the lip of the fask Add 0.1g concentrated NH OH. Place a 19/22 White rubber septum over the top of the fask, purge Clamp the flask 1-2 ãabo eastr plate and let the o a small balloon attached to the side 0.1g of CuC catlalyst to the flask Tollowed by 10 mt 95% ethanol 1.0 mL- of 2-methy-3butyn-2-ol, and 0.5mf ygen for1 minute, then fill the baltoon untit mosty inflated- (Your instructor wil you with this procedure. ur. A greenish-blue or blue color should begin to develop almost imme diately. If the batoon deflates substantially, refill it with more oxygen. Stir for 1 hour to mix the slurry well at and every few minutes swirl the flask . Open the reaction flask, cool if warm, and add 0.5 m L of concentrated hydrochloric acid to neutralize the NH OH and keep the copper compounds in solution. Th colo a few more drops of acid. Add 2.5 mL of saturated NaÄI solution to precipitate Pasteur pipette, until all n. The color will change from b in color ater mixing thoroughly, add or yellow, If the mi the diol and stir the sion that results Add MTBE (methyl t-butyl ether) in 2mL increments, mixing well using a organic solids dissolve (add up to 6 mL MTBE, but no more). [Note: If a te precipitate forms, add additional water to the mixture to dissolve it. All solids should be dissolved at this point. Fransfer the mixture to a centrifuge tube and separete the two layers by removing the bottom ayer using a Pasteur pipette: Add-about 3mL of saturated NaCl solution to the organic layer and mix well using the pipette. Allow the layers to separate and again remove the bottom layer. The organic layer-shoutd be clear and cotortess or light yellow (IF NOTwash again with another 3 ml of saturated aqueous NaCt and separate the layers).Transfer the organic layer to a dry 16x100-mm-test tube and dry the solution with anhydrous sodium sulfate (use approximately the amount you would need to cover a dime) for at least 10 min: The drying agent should remain granular in appearance. Using a Pasteur pipette, transfer the organic layer to a 10mt Erlenmeyer flask teaving the drying agent behind Add-Norit activated charcoat (use approximately the amount you would need to cover a dime and boil the with a small cotton plug and about 1 cm of Celite. Use compressed air and a dry condenser hose to speed the filtration if necessary mixture gently for 2 minutes Filter the cooled solution through a fiter pipet fitted Rapidly boil off all the solvent on a hot plate set to -80Â°C in the hood. When the boiling, remove it from the heat. You should have a solid residue at this point. At your bench remove the last traces of solvent by connecting the flask to a vacuum trap apparatus using the thermometer adapter and a short glass tube solution stops At your bench, recrystallize the product from a minimal amount of boiling toluene. You will need to use a heating mantle to generate sufficient heat to boil toluene. Cool the solution slowly to room temperature, then cool on ice. Isolate the product using the Hirsch funnel rinsing the product with a small amount (ca. 0.5-1.0 mL) of ice-cold toluene. Allow the product to air dry in a sample envelop in your drawer until next week, and then determine the mp and yield. Submit your product (label as Diyne' with your 1 initial last name, w, and mp) to your instructor The aqueous filtrate from the reaction mixture should be placed in the acidic aqueous waste. The filtrates from recrystallization of the diol should be placed in the or Clean up: ganic non-halogenated waste

CHEM 235 Lecture Notes - Lecture 6: Ground Glass Joint, Boiling Chip, Petroleum Ether

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