BOSTON UNIVERSITY DRESDEN SCIENCE PROGRAM ORGANIC CHEMISTRY LABORATORY

BOSTON UNIVERSITY DRESDEN SCIENCE PROGRAM ORGANIC CHEMISTRY LABORATORY CAS CH 203, FALL 2018 4. Prelab Radical Bromination of p-Toluic acid

Radical Bromination of p-Toluic acid You will be conducting two different experiments: 1. Radical bromination of p-toluic acid 2. Test of radical bromination of different hydrocarbons Halogenes (chlorine and bromine) can react with saturated hydrocarbons only via free radical substitution reaction. Alkyl or cycloalkyl halides are formed.

Part 2: Test of radical bromination of hydrocarbons/ radical stabilty The hydrocarbons that will be tested are cyclohexane, methylcyclohexane, toluene (methyl benzene), ethylbenzene, isopropylbenzene (cumene), and t-butylbenzene. Radical stability 3° benzylic > 2° benzylic > 1° benzylic > 3° aliphatic > 2° aliphatic > 1° aliphatic > aromatic

Safety and hazards: Bromine N-bromosuccinimide Benzoyl peroxide Potassium bromate Hydrochloric acid Chlorobenzene Petroleum ether Hydrocarbons (general) Benzyl halides (general)

Bromine Formation / Bromide-Bromate- Reaction 5 KBr + KBr. O 3 + 6 HCl 3 Br 2 + 3 H 2 O + 6 KCl

Exp. 4 - Synthesis of 4 -(bromomethyl)benzoic acid Technique 3 – Reaction Methods

Exp. 4 - Synthesis of 4 -(bromomethyl)benzoic acid Technique 3 – Reaction Methods

Exp. 4 - Synthesis of 4 -(bromomethyl)benzoic acid Technique 8 – Simple Distillation

Exp. 4 - Synthesis of 4 -(bromomethyl)benzoic acid Technique 7 – Extractions, Separations, and Drying Agents

Exp. 4 - Synthesis of 4 -(bromomethyl)benzoic acid Technique 7 – Extractions, Separations, and Drying Agents

Exp. 13 B - Synthesis of 4 -(bromomethyl)benzoic acid Technique 7 – Extractions, Separations, and Drying Agents

Exp. 13 B - Synthesis of 4 -(bromomethyl)benzoic acid Technique 7 – Extractions, Separations, and Drying Agents

Exp. 4 - Synthesis of 4 -(bromomethyl)benzoic acid Technique 7 – Extractions, Separations, and Drying Agents

Exp. 4 - Synthesis of 4 -(bromomethyl)benzoic acid Technique 7 – Extractions, Separations, and Drying Agents

Exp. 4 - Synthesis of 4 -(bromomethyl)benzoic acid Technique 7 – Extractions, Separations, and Drying Agents

Exp. 4 - Synthesis of 4 -(bromomethyl)benzoic acid Technique 7 – Extractions, Separations, and Drying Agents

Exp. 4 - Synthesis of 4 -(bromomethyl)benzoic acid Technique 7 – Extractions, Separations, and Drying Agents Extraction: Supposed system: K = 10, 50 mg compound in 1 m. L water (solvent 1) 3 x extraction with 0. 5 m. L ether (solvent) each in comparison to 1 x extraction with 1. 5 m. L xether = amount remaining in the aqueous phase Distribution coefficient

Exp. 4 - Synthesis of 4 -(bromomethyl)benzoic acid Technique 7 – Extractions, Separations, and Drying Agents

Exp. 4 - Synthesis of 4 -(bromomethyl)benzoic acid Technique 7 – Extractions, Separations, and Drying Agents

Exp. 4 - Synthesis of 4 -(bromomethyl)benzoic acid Technique 7 – Extractions, Separations, and Drying Agents

Exp. 4 - Synthesis of 4 -(bromomethyl)benzoic acid Appendix 3 – IR Spectroscopy wavenumber unit: cm-1

Exp. 4 – Synthesis of 4 -(bromomethyl)benzoic acid Appendix 3 – IR Spectroscopy

Exp. 4 - Synthesis of 4 -(bromomethyl)benzoic acid Appendix 3 – IR Spectroscopy

Exp. 4 - Synthesis of 4 -(bromomethyl)benzoic acid Appendix 3 – IR Spectroscopy

Exp. 4 - Synthesis of 4 -(bromomethyl)benzoic acid Appendix 3 – IR Spectroscopy

Exp. 4 - Synthesis of 4 -(bromomethyl)benzoic acid Appendix 3 – IR Spectroscopy IR Spectra of 4 -methylbenzoic acid and 4 -(bromomethyl)benzoic acid

Exp. 4 - Synthesis of 4 -(bromomethyl)benzoic acid NMR- Spectra of p-Toluic acid

Exp. 4 - Synthesis of 4 -(bromomethyl)benzoic acid NMR- Spectra (calculated)

4 -methylbenzoic acid 4 -(bromomethyl)benzoic acid

4 -methylbenzoic acid 4 -(bromomethyl)benzoic acid

Exp. 4 - Synthesis of 4 -(bromomethyl)benzoic acid Appendix 3 – IR Spectroscopy