Step 1: Hydroformylation
Step 2: Puri cation
Aldehyde
O -gas
CO + H
Liquid/ l iquid separator 5˚C 40 bar
Liquid/ g as separator 120˚C 1 bar
Distillation 15 mbar Head 80˚C Bottom 135˚C
Reactor 70 - 120 ˚C 5 - 20 bar
Catalyst recycle
Ole n
ole n recycle
Figure 4 Process flow of the hydroformylation reaction for large-volume chemicals production using the hydroformylation process
during his work on the Fischer-Tropsch (FT) process, marked a milestone in industrial chemistry. Roelen observed that introducing ethylene into a FT reactor produced aldehydes and diethylketone and identified HCo(CO)₄ as an effective cobalt catalyst. The process was initially termed the ‘oxo process’ or ‘oxo synthesis’. The hydroformylation process involves the addition of carbon monoxide (CO) and hydrogen (H₂) to unsaturated compounds, typically alkenes or alkynes, to form aldehydes. Although discovered somewhat accidentally, with the first patent filed in 1938, the reaction has evolved into one of the largest homogeneously catalysed industrial processes and remains a cornerstone of industrial chemistry, playing a crucial role in synthesising aldehydes that serve as precursors for alcohols, amines, carboxylic acids, and other bulk chemicals (see Figure 2 ), at scale for detergents, paints, pharmaceuticals, and other applications. Its significance continues to grow, particularly within integrated refining and petrochemical operations. Industrial applications of hydroformylation The hydroformylation process serves as a critical source for millions of tons of industrial chemicals produced annually. Its large-scale industrial application is driven by the abundant availability of 1-alkenes, primarily derived from the petrochemical sector.³ , ⁴ , ⁵ Although a broad spectrum of olefins – including long-chain, branched-chain, and cyclic types – can undergo hydroformylation, the process predominantly employs ethylene and propylene as primary feedstocks to produce propionaldehyde, n-butyraldehyde, and iso-butyraldehyde. They
serve as key intermediates for downstream applications in paints, plasticisers, solvents, coatings, and adhesives (see Figure 3 ). At the core of oxo-alcohol production, hydroformylation plays an indispensable role. To produce these essential intermediates, BPCL has adopted the advanced LP Oxo Selector M30 hydroformylation technology, licensed from Johnson Matthey, UK.6 Complementing this, BPCL's butyl acrylate unit, with an installed capacity of 130 KTPA, is licensed by Mitsubishi Chemical Corporation, Japan, making it one of the largest single-unit facilities of its kind globally. As a result, BPCL has emerged as one of the largest producers of oxo-alcohols, with annual production capacities of 150 KTPA for n-butanol, 55 KTPA for 2-ethylhexanol, and 7 KTPA for iso-butanol. Traditionally, the hydroformylation reaction is carried out under homogeneous catalytic conditions, utilising transition metal complexes – primarily rhodium or cobalt – dissolved in the reaction medium, and operated at elevated pressures ranging from 10 to 100 atm and temperatures between 40 and 200°C.5 Rhodium-based catalysts offer lower
BPCL’s product portfolio based on propylene hydroformylation process
Sr No
Chemicals
Production Industrial capacity (KTPA) applications
Plasticisers,
1
N-butanol
150
solvent,
2 3
2 Ethyl Hexanol 55
paints and coatings, adhesives
Iso-Butanol
7
Table 1
Refining India
19
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