Sodium Borohydride Reduction of Cyclohexanone.edited

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1 SODIUM BOROHYDRIDE REDUCTION OF CYCLOHEXANONE Student’s Name Institutional Affiliation Course Instructor’s Name Date

2 Sodium Borohydride Reduction of Cyclohexanone Objective To synthesize cyclohexanol using sodium borohydride to reduce Cyclohexanone. To employ IR spectroscopy to characterize the reduction product. Materials and Equipment Large test tube Measuring cylinder 250 ml beaker Spatula Pasteur pipette Separatory funnel Retort stand Ring clamp Bus head flow retort stand Test tube rack Conical flask Filter paper Bottle sample

3 Aluminum foil Rotary evaporimeter IR spectrometer 1 ml conical viol Magnetic stirrer Heating mantle Triangular spin vial Septum Erlenmeyer flask Dropper Name Formula and Structure Mass (g/mo l) MP ( ) ℃ BP ( ) ℃ Densi ty (g/mo l) Color Solid/Liq uid Cyclohexanol C6H12O 100.1 6 25.9 3 161. 8 0.962 Colorle ss Viscous liquid

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4 Cyclohexanone C6H10O 98.15 -31 155. 6 0.948 yellow Oily liquid water H2O 18.02 0 100 1 colorle ss liquid Sodium sulfate Na2SO4 142.0 4 884 1.42 9 2.66 white Crystalline solid Sodium hydroxide NaOH 39.99 7 318 138 8 2.13 colorle ss liquid Methanol CH3OH 32.04 - 97.6 64.7 0.792 colorle ss liquid Sodium borohydride NaBH4 37.83 400 500 1.07 colorle ss liquid

5 Dichloromethane CH2Cl2 84.93 - 96.7 39.6 1.33 colorle ss liquid 4 – tertbutylcyclohex none C10H18O 154.2 5 48.5 224 0.9 colorle ss liquid Ethanol C2H5OH 46.07 - 114. 1 18.3 7 0.789 Colorle ss liquid Hydrochloric acid HCL 36.45 8 -74 - 85.0 5 1.2 colorle ss liquid Procedure Sodium Borohydride Reduction of Cyclohexanone

6 Procedure observation 1.Put 5 ml of methanol in the large test tube Colorless solution 2. Add 2 ml cyclohexanone in the test tube containing methanol Colorless solution 3. In an ice bath, cool the test tube 4. add 200 mg of sodium borohydride in the test tube containing the mixture Rigorous reaction 5. place the test tube in an ice bath and remove it after the vigorous reaction ceases. Allow it to cool to room temperature for 10 minutes Brown solution 6. add 5 ml of 3M NaOH solution to decompose the borate ester 7. to the mixture, add 4 ml distilled water Two layers observed 8. transfer the upper layer (Produce) into another clean test tub or conical flask using a Pasteur pipette 9. transfer the rest of the content into the separating funnel 10. add 5 ml of Dichloromethane in the separating funnel to extract the remaining product Two layers formed 11. separate the mixture to remove the bottom layer 12. add Dichloromethane from the separatory funnel into the initial product Cloudy solution 13. repeat step 11 and 12 Cloudy solution 14. add 2,0 gram of anhydrous sodium sulfate 15. filter the solution using a fluted filter Clear solution

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7 paper 16. into a small dry round-bottomed flask transfer the solution Colorless solution 17. Using the rotary evaporimeter, evaporate the solvent Dichloromethane Colorless solution Stereoselective Reduction of 4- Tert- Butyl cyclohexanone Procedure Procedure observations 1. Add 0.1 gram of 4- tertbutylcylohexanone 2. Set the heating mantle and place the viol at the center of the hot plate 3. Add the triangular spin viol with the cup with a septum. 4. Loosely close the conical vial with the cup with a septum. 5. Dissolve sodium borohydride in dry ethanol and shake thoroughly Cloudy solution 6. Using a syringe, measure 1 ml of Rigorous reaction

8 sodium borohydride in ethanol solution and inject it through the septum into the solution in the conical viol 7. Using a pipette add 1 ml of HCL dropwise Rigorously reaction 8. Add 2 ml of DCM and turn on the stirrer Two layers formed 9. Using a pipette such as the lower organic phase and transfer it into an Erlenmeyer flask 10. Repeat step 8 and 9 11. Add 1 gram of anhydrous sodium sulfate. 12. Poor the dry solution over the funnel and rinse the Erlenmeyer flask with Dichloromethane. 13. Set a sand bath with temp below 100 degrees Celsius, and place the vial deep inside the sand bath Vigorous reaction Results The reaction leading to the formational of cyclohexanol has a mole ratio of 1:1 Cyclohexanone and cyclohexanone. Number of moles of cyclohexanol = Mass/rfm = 7.5g/100.16g/mol

9 = 0.0749 moles Number of moles of cyclohexanone = mass/rfm = 10.3g/ 98.15 g/mol = 0.1049moles % yield = (0.0749/0.1049) *100 = 71.40 % = 71.4% Discussion Cyclohexanone was reacted with sodium borohydride in methanol, and a rigorous reaction was observed. The relentless reaction represented the reduction process. Sodium borohydride was oxidized, hence was used as the reducing agent, which ensured the successful Reduction of Cyclohexanone into cyclohexanol. It is thus evident that cyclohexanol was oxidizing since, in the process, it was reduced. Since sodium borohydride was employed in excess limiting agent, it was necessary to add sodium hydroxide responsible for decomposing the borate ester. Water was then added to this mixture to provide the proton needed to react with aldol product to form the cyclohexanol. Two layers were observed where the upper layer represented the product desired while the lower layer was the aqueous solution which was denser than the product, hence the reason it was at the bottom. Dichloromethane was employed in the experiment to extract all the products and ensure that total transfer was a success. Since the product contained both water and the solvent dichloromethane, anhydrous sodium sulfate was added to draw out all the water and free it from moisture. Furthermore, to remove all the Dichloromethane, the product was placed in the rotary

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10 evaporimeter where all the DCM solvent was evaporated since it a volatile polar solvent. Hence the product that remained was the desired cyclohexanol, and therefore the objective of the experiment was achieved. In experiment two concerning 4- tert butyl cyclohexanone, it was reacted with the reducing agent's sodium borohydride. The 4 – tert butyl cyclohexanone was the oxidizing agent as its self was reduced in the process. These were reacted together in ethanol, which offered a conducive condition for the reaction. Hydrochloric acid was added to the response to protonate the aldol product formed to convert into the desired alcohol, 4- tertbutyl cyclohexanol. Furthermore, the DCM employed was employed for complete extraction, ensuring that the product created had a correct percent yield. Furthermore, to ensure that the product was pure, alcohol anhydrous sodium sulfate was added to draw out all the water. The product formed was then heated on a heating mantle to create a sample to run on the IR spectrometer to identify if the product was alcohol. The IR spectrometer printout showed that O-H was present in 3650 – 3200 cm-1. Conclusion This experiment was a success as the objective of reducing Cyclohexanone to obtain cyclohexanol was accomplished. It involved reacting sodium borohydride and Cyclohexanone in methanol forming cyclohexanol. The reaction yield was 71.4 %. The primary reason it was not 100% percent may include an error in measuring weight, and the filtration processes in the total mixture could not have been transferred, resulting in losses. Furthermore, 4- tertbutylcyclohexanone, which involved sodium hydroxide reaction and the 4- tertbutylcyclohexanone in ethanol's presence, gave the alcohol after IR analysis, and it

11 ascertained that it was alcohol as it had an O- H bond present at the 3200 to 3650 cm-1. Most of the figures were recorded into four decimal places, but the percent yield was three significant figures. References https://www.google.com/search? q=density+of+hydrochloric+acid&sxsrf=ALeKk03UKNvwCV93qsMdjKeHusvF2Bb8q A %3A1617621666001&ei=ofJqYMDUPM2J1fAP6ZiN8Ak&oq=density+of+hydrochloric +acid&gs_lcp=Cgdnd3Mtd2l6EAMyAggAMgYIABAHEB4yAggAMgIIADICCAAyAg gAMgQIABAeMgQIABAeMgQIABAeMgQIABAeOgcIABBHELADOgcIABCwAxB DOgcIIxCwAhAnOggIABAIEAcQHjoICAAQBxAFEB5QidgBWIbzAWC5_gFoAXAC eAGAAeQFiAGSKZIBCzItNS42LjEuMS4xmAEAoAEBqgEHZ3dzLXdpesgBCsABA Q&sclient=gws- wiz&ved=0ahUKEwiAqaGm_ubvAhXNRBUIHWlMA54Q4dUDCA0&uact=5 https://www.youtube.com/watch?v=Zu9D83kMCWU https://www.youtube.com/watch?v=Zu9D83kMCWU Wang, X., Bian, W., Ma, Y., Liu, Y., Wang, Z., Shi, C., ... & Kang, Z. (2021). Hydroxyl- terminated carbon dots for efficient conversion of cyclohexane to adipic acid. Journal of Colloid and Interface Science , 591 , 281-289.

12 Zhao, C., Zhang, Z., Liu, Y., Shang, N., Wang, H. J., Wang, C., & Gao, Y. (2020). Palladium Nanoparticles Anchored on Sustainable Chitin for Phenol Hydrogenation to Cyclohexanone. ACS Sustainable Chemistry & Engineering , 8 (32), 12304-12312.

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