Lecture 13 CATALYSIS OXIDATION OF ALKENES Copyright The

Lecture 13 CATALYSIS – OXIDATION OF ALKENES Copyright ©The Mc. Graw-Hill Companies, Inc. Permission required for reproduction or display.

Acetaldehyde – of commercial importance - oxidation to acetic acid - dehydration to acetic anhydride Previous synthetic route: Today, Wacker process is used producing 4 million tons of acetaldehyde from ethylene. ETHYLENE OXIDATION TO ACETALDEHYDE: WACKER PROCESS

Net Reaction: CH 2=CH 2 + Pd. Cl 2 + H 2 O Pd(0) + 2 Cu. Cl 2 Pd. Cl 2 CH 3 C(=O)H + Pd(0) + 2 HCl + 2 Cu. Cl + 2 HCl + 1/2 O 2 2 Cu. Cl 2 + H 2 O _________________________ CH 2=CH 2 + 1/2 O 2 CH 3 C(=O)H WACKER PROCESS Ho = -243 k. J/mol

THE WACKER PROCESS

WACKER PROCESS

Step a Two Cl ions are displaced and substituted with alkene and H 2 O WACKER PROCESS

Step b Attack of a nucleophile (H 2 O) on the alkene WACKER PROCESS

Step c Loss of Cl WACKER PROCESS

Step d -elimination ALKENE DIMERIZATION AND OLIGOMERIZATION

Step e ALKENE DIMERIZATION AND OLIGOMERIZATION

Step g Regeneration of Pd(II) ALKENE DIMERIZATION AND OLIGOMERIZATION

EPOXIDATION OF ALKENES

EPOXIDATION OF ALKENES

Lecture 13 CATALYSIS – CARBONYLATION AND CARBOXYLATION REACTIONS Copyright ©The Mc. Graw-Hill Companies, Inc. Permission required for reproduction or display.

Main industrial processes using CO: Synthesis of methanol Fischer-Tropsch process Hydroformylation process Synthesis of acetic acid Production of formic acid Synthesis of dimethyl carbonate Synthesis of polyketones CARBONYLATION and CARBOXYLATION

MONSANTO PROCESS

MONSANTO PROCESS

OLEFIN HYDROFORMYLA TION : THE OXO PROCESS

CARBONYLATION OF ALKENES/ALKYNES : REPPE RXN

Production of methyl methacrylate (MMA) – an intermediate for the polymer synthesis of plexiglass. CARBONYLATION ALKENES AND ALKYNES

Synthesis of ployketones: In the absence of methanol CARBONYLATION OF ALKENES AND ALKYNES

Industrial application of the Reppe reaction using alkynes: Acrylic acid synthesis. CARBONYLATION OF ALKENES AND ALKYNES

CARBOXYLATION