Meilen, 16.12.2007 Organic chemistry practical course (OCPI) HS 07 529-0229-00 Fabienne Vukotic 06-910-541 D-BIOL Assistant: Guo Xiaoqiang Synthesis of Adipic acid 1. Method The method for the synthesis of Adipic acid is an oxidation of cyclohexanone with potassium permanganate as the oxidizing agent and sodium hydroxide as a basic catalyst. 2. Reaction Equation O O KMnO4 OH HO NaOH H2 O O 3. Mechanism O O O O O H OH O - H2 O Mn O O Mn O O O H O O O + MnO4 O O OH HO O O O O 4. Physical and Chemical Properties of Substances Potassium permanganate CAS: 7722-64-7 M: 158.03 g/mol mp: 50 °C CH-toxicity class: 3 Risk Phrases -R8: Contact with combustible material may cause fire -R22: Harmful if swallowed -R50/53: Very Toxic to aquatic organisms, may cause long-term adverse effects in the aquatic environment Safety Phrases -S60: This material and/or its container must be disposed of as hazardous waste -S61: Avoid release to the environment. Cyclohexanone CAS: 108-94-1 M: 98.14 g/mol d: 0.947 g/mL at 25 °C bp: 155 °C mp: -47 °C n20D: 1.450 MAK: 200 mg/m3, 50 mL/m3 CH-toxicity class: 4 Risk Phrases -R10: Flammable -R20: Harmful by inhalation Safety Phrases -S25: Avoid contact with eyes Sodium hydroxide CAS: 1310-73-2 M: 40.00 g/mol mp: 318 °C CH-toxicity class: 2 Risk Phrases -R35: Causes severe burnsIrritating to eyes, respiratory system and skin Safety Phrases -S26: In case of contact with eyes, rinse immediately with plenty of water and seek medical advice -S37/39: Wear suitable gloves and eye/face protection -S45: In case of accident or if you feel unwell, seek medical advice immediately (show label where possible) Hydrochloric acid (conc.) CAS: 7647-01-0 M: 36.46 g/mol d: 1.19 g/mL at 25 °C bp: 85 °C mp: -25 °C MAK: 7 mg/m3, 5 mL/m3 CH-toxicity class: 2 Risk Phrases -R34: Causes burns -R37: Irritating to the respiratory system HCl Acetic acid CAS : 64-19-7 Safety Phrases -S26: In case of contact with eyes, rinse immediately with plenty of water and seek medical advice -S36/37/39: Wear suitable protective clothing, gloves and eye/face protection -S45: In case of accident or if you feel unwell, seek medical advice immediately (show label where possible) M: 60.05 g/mol d: 1.049 g/mL at 25 °C bp: 117-118 °C mp: 16.2 °C n20D: 1.3716 MAK: 25 mg/m3, 10 mL/m3 CH-toxicity class: 4 Risk Phrases -R10: Flammable -R35: Causes severe burns Safety Phrases -S23: Do not breathe gas/fumes/vapor/spray (appropriate wording to be specified by the manufacturer) -S26: In case of contact with eyes, rinse immediately with plenty of water and seek medical advice -S45: In case of accident or if you feel unwell, seek medical advice immediately (show label where possible) Adipic acid CAS: 124-04-9 M: 146.14 g/mol D: 0.88 g/mL CH-toxicity class: 4 Risk Phrases -R36: Irritating to the eyes bp: 265 °C mp: 151-154 5. Experimental Setup reflux: vacuum filtration: 20o 20o safety bottle vacuum 500 mL NS 14 20o 250 mL LaboBib© 300 50 AN AN AUS AUS 1500 500 100 o 0 U/min 250 C 200 150 1000 750 6. Amounts of Substance used Substance measured amount [ml] 3.1 [g] [mmol] eq Cyclohexanone 2.95 30.1 1.04 KMnO4 9.15 57.9 2.0 Water 75 NaOH (10%) 10 drops Potassium permanganate is the limiting reactant since it requires two equivalent for one equivalent cyclohexanone. 7. Experimental Section (Procedure) In a 250 mL round bottom flask, 9.15 g (2.0 eq.) of KMnO4 are dissolved in 75 mL of water and, while stirring, 2.95 g (1.04 eq.) of cyclohexanone are added. The resulting mixture is heated to 30 °C and 10 drops of a 10 % NaOH solution are added. The Temperature is then raised to 50 °C for 20 min and then to 100 °C for 1 min. After the mixture has cooled down to RT, it is acidified to pH 0 using concentrated HCl. It is put in an ice bath for 15 min for crystallization. The crystals are vacuum filtered, washed with cold water, and characterized. 8. Yield The theoretical yield is 28.95 mmol. The experimental yield is 1.29 g = 8.83 mmol. The yield percentage therefore is 30.5% 9. Characterization Melting point A melting point range of 151 -154 °C was measured. The literature value for adipic acid is 104 -107 °C. IR-Spectrum (see attachement) bands [cm-1] 3200 – 2400 2951 1685 interpretation COOH sat. C-H C=O Literature spectrum http://riodb01.ibase.aist.go.jp/sdbs/cgi-bin/direct_frame_top.cgi 10. Remarks and Discussion The yield is relatively low but the product can be identified as the desired substance by its IR spectrum and the measured melting point. 11. Literature Coblentz Society, Inc., "Evaluated Infrared Reference Spectra" in NIST Chemistry WebBook, NIST Standard Reference Database Number 69, Eds. P.J. Linstrom and W.G. Mallard, June 2005, National Institute of Standards and Technology, Gaithersburg MD, 20899. NIST Chemistry Webbook. 4 Dec. 2007 <http://webbook.nist.gov>. EMolecules - Searching the World's Chemistry. 2007. EMolecules, Inc. 4 Dec. 2007 <http://www.emolecules.com>. IGS Giftliste. 31 July 2007. BAG. 4 Dec. 2007 <http://igs.naz.ch/igs/igsServer/de.kisters.igs.igs40.servlets.igs40Servlet>. Kirste, Burkhard. "Chemikalien: Sicherheitsdaten." Institut für Chemie und Biochemie an der FU Berlin. 28 July 1994. FU Berlin. 4 Dec. 2007 <http://www.chemie.fu-berlin.de/chemistry/safety/chemsafety.html>. "Risk & Safety." Sigma-Aldrich. 2007. Sigma-Aldrich Co. 4 Dec. 2007 <http://www.sigmaaldrich.com/Help_Pages/Help_Welcome/Product_ Search/Risk___Safety_Statements.html#Safety%20Phrases>. Sigma-Aldrich. 2007. Sigma-Aldrich Co. 4 Dec. 2007 <http://www.sigmaaldrich.com/Area_of_Interest/Europe_Home/ Switzerland__Schweiz_.html>.