20.3 Oxo processing of olefins

20.3.1 Introduction

In an oxo process, we react an olefin with synthesis gas to obtain aldehyde i.e.,

Olefin + CO + H₂ → Aldehyde.

This reaction is called as hydroformylation.

Dimerization (Option): Alternatively, if desired, the aldehyde dimerization reaction can be also carried out. In that case, two molecules of aldehydes react to obtain a higher order aldehyde.

In short, the oxo processing can be targeted to generate both short chain and long chain aldehydes.

Hydrogenation (Option): When short and long chain aldehydes are subjected to hydrogenation then one can produce alcohol or an acid.

Oxygenation (Option): When short and long chain aldehydes are subjected to reaction with oxygen or air, then acids can be formed.

Thus the oxo processing of olefins can generate.

• • Short and long chain aldehydes

• Short and long chain alcohols

• Short and long chain acids

Therefore, gases can be converted into these useful products. Various applications of these compounds include plasticizers for polymerization reactions, solvents, detergent raw materials etc.

The process will be demonstrated for propylene but can be suitably extended to other alkenes such as butylenes or ethylene.

20.3.2 Reactions and Operating conditions

  Addition reaction

• • Catalyst: Cobalt naphthanate.

• Operating conditions: Pressure of 100 – 400 atms and temperature of 100 – 200°C.

• The reaction is exothermic.

• Reaction occurs on a packed bed reactor where the packed bed acts as a surface to deposit the catalyst i.e., Cobalt.

• In due course of reaction, the Cobalt enters the product stream and therefore needs to be recovered.