Constants and Formulae Avogadro's constant, NA = 6.0221×1023 mol–1 Boltzmann constant, kB = 1.3807×10–23 J K–1 Universal gas constant, R = 8.3145 J K–1 mol–1 = 0.08205 atm L K–1 mol–1 Speed of light, c = 2.9979×108 m s–1 Planck's constant, h = 6.6261×10–34 J s Faraday constant, F = 9.64853399×104 C Mass of electron, me = 9.10938215×10–31 kg Standard pressure, P = 1 bar = 105 Pa Atmospheric pressure, Patm = 1.01325×105 Pa = 760 mmHg = 760 torr Zero of the Celsius scale, 273.15 K 1 picometer (pm) = 10–12 m; 1 Å = 10-10 m; nanometer (nm) = 10–9 m 1 eV = 1.6 × 10-19 J 1 amu = 1.66053904 × 10-27 kg Ideal gas equation: PV = nRT Enthalpy: H = U – PV Gibbs free energy: G = H – TS Entropy change: , where qrev is heat for the reversible process (for isothermal expansion of an ideal gas) Nernst equation: Energy of a photon: Lambert-Beer law: Integrated rate law Zero order First order Second order Arrhenius equation Periodic table of elements
Characteristic 1H NMR Chemical Shifts Type of Hydrogen (R=Alkyl, Ar=Aryl) Chemical Shift (ppm) Type of Hydrogen (R=Alkyl, Ar=Aryl) Chemical Shift (ppm) (CH3)4Si 0 (by definition) RCH3 0.9 RCH=O 9.5-10.1
IR Absorption Frequencies of Functional Groups Containing a Carbonyl (C=O) Functional Group Type of Vibration Characteristic Absorptions (cm-1) Intensity Carbonyl C=O stretch 1670-1820 strong (conjugation moves absorptions to lower wave numbers) Acid C=O stretch 1700-1725 strong O-H stretch 2500-3300 strong, very broad C-O stretch 1210-1320 strong Aldehyde C=O stretch 1740-1720 strong =C-H stretch 2820-2850 & 2720-2750 medium, two peaks Amide C=O stretch 1640-1690 strong N-H stretch 3100-3500 unsubstituted have two bands N-H bending 1550-1640 Anhydride C=O stretch 1800-1830 & 1740-1775 two bands Ester C=O stretch 1735-1750 strong C-O stretch 1000-1300 two bands or more Ketone acyclic stretch 1705-1725 strong cyclic stretch 3-membered - 1850 4-membered - 1780 5-membered - 1745 6-membered - 1715 7-membered - 1705 strong ,-unsaturated stretch 1665-1685 strong aryl ketone stretch 1680-1700 strong Data from http://www2.ups.edu/faculty/hanson/Spectroscopy/IR/IRfrequencies.html Fields of Advanced Difficulty Theoretical
inhibits COX enzyme results in the decrease in the production of prostaglandins and thromboxanes, the key molecules that affect various physiological responses including transmission of pain, regulation of inflammation and fever, as well as aggregation of platelets. In this task, you will: Perform the synthesis of acetylsalicylic acid via the esterification of salicylic acid with acetic anhydride. Calculate % yield of the purified product. Perform thin layer chromatography analysis. Chemicals Acetic anhydride Ethyl acetate Concentrated H2SO4 (18 mol dm-3) Hexane Distilled Water Ice (for an ice bath) Ethanol Salicylic acid Glasswares Beaker, 100 cm3 Buchner funnel Crystallizing dish (for a hot water bath and an ice bath) Erlenmeyer flasks, 125 cm3 and 250 cm3 Filter paper Graduated cylinder, 25 cm3 Pasteur pipet and rubber bulb Stirring rod Spatula Suction flask Capillary tube for TLC TLC plate on aluminum foil or glass supports and TLC jar Instruments Analytical balance ( 0.0001 g) Hotplate Water aspirator or vacuum pump Stand and clamps Procedure: 1. Weigh out 5.00 g of salicylic acid. Transfer this to a 125 cm3 Erlenmeyer flask. Record the mass.