ELIMINATION KINETICS OF DL -MANDELIC ACID IN THE GAS PHASE

✍ Scribed by Gabriel Chuchani; Ignacio Martin

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 42 KB
• Volume: 10
• Category: Article
• ISSN: 0894-3230
• DOI: 10.1002/(sici)1099-1395(199702)10:2<121::aid-poc870>3.0.co;2-8

✦ Synopsis

DL-Mandelic acid was pyrolyzed in a static reaction vessel over the temperature range 300•1-340•0 °C and pressure range of the substrate 15•2-52•1 Torr. The reaction, in a seasoned vessel and in the presence of the free radical inhibitor cyclohexene, is homogeneous, unimolecular and obeys a first-order rate law. The reaction yielded benzaldehyde, CO, H 2 O and small amounts of benzyl alcohol and CO 2 . The rate coefficients followed the Arrhenius equation: log k 1 (s Ϫ 1 ) = (12•54 ± 0•12) Ϫ (171•3 ± 1•4) kJ mol Ϫ 1 (2•303RT) Ϫ 1 . The present result may imply a unimolecular elimination involving a semi-polar five-membered cyclic transition-state mechanism. Steric factor appears not to be important in rate enhancement.