2 EH Production

2-Ethylhexanol (2-EH) Production and Manufacturing Process 23 April 2010 10:11 [Source: Chemical Report] The industrial production of 2-ethylhexanol is by a three-step process involving the aldol selfcondensation of n-butyraldehyde followed by dehydration and hydrogenation. The n-butyraldehyde was originally obtained from acetaldehyde via ethylene but this has been superseded by the oxo process frompropylene. Today, nearly all 2-EH is produced by catalytic hydroformylation of propylene with synthesis gas (carbon monoxide and hydrogen). The catalytic process now mostly uses rhodium catalysts rather than the older cobalt hydrocarbonyl catalysts. Davy Process Technology (formerly Kvaerner) and Dow (Union Carbide) jointly have led the development of newer catalytic technologies and have developed a phosphite ligand modified rhodium catalyst. The two companies have also dominated the licensing of 2-EH process technology. Shell has developed and operates a one-step process that converts propylene directly to butanol, iso-butanol and 2-ethylhexanol.

INTRODUCTION The Oxo process, more formally known as hydroformylation, is the common name for a reaction of an olefin with carbon monoxide and hydrogen to give an aldehyde. Subsequent hydrogenation of the aldehyde leads to an oxo alcohol . The chronological development of oxo alcohol process technology is illustrated below:

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1938 - Oxo process discovered by Otto Roelen of Ruhrchemie using a cobalt catalyst. 1940s/1950s - Various companies develop their own versions of the oxo process (e.g., ICI, BASF, PCUK, Eastman). 1960s - Shell develops a modified cobalt process, using ligands such as phosphines or phosphites. ICI improved its High Pressure Oxo Process with an unliganded rhodium catalyst. 1970s - Union Carbide Corporation, Davy Process Technology, and Johnson Matthey developed the LP Oxo (modified rhodium) process, using triphenylphosphine ligand (PPh3). Key features are much lower operating pressure and good normal to iso ratio. Aldehyde is separated as vapor in the original gas recycle version of the flowsheet. 1980s - Rhône Poulenc/Ruhrchemie develops a two-phase process using a water-soluble modified rhodium catalyst with TPP sulfonate ligand.

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UCC and Davy developed a liquid recycle variation of the LP Oxo process offering advantages over gas recycle for some situations. o BASF starts up an LP Oxo process. Early 1990s - UCC and Davy, (see note below) improves the LP Oxo process capable of taking both propylene and raffinate-2 feeds, including commercially available mixed butene streams, for the production of butanols, 2 EH and 2-PH. The process uses a highly active modified rhodium catalyst system and has a “single-pass” flow scheme, which is simpler than the earlier gas or liquid recycle LP Oxo variants. Late 1990s - BASF patents butadiene route to n-butanol/n-butyraldehyde. Early 2000s - Davy and Johnson Matthey license their Johnson Matthey Oxo Alcohols Process™ (formerly the ICI High Pressure Oxo Process) for the production of higher oxo alcohols (INA and

The oxo process involves production of aldehydes by hydroformylation, which is defined as the addition of synthesis gas (a mixture of carbon monoxide and hydrogen) to an olefin. The initial product is most commonly an aldehyde, which can be hydrogenated to the corresponding alcohol, oxidized to the acid or converted to other derivatives. By far the most important oxo chemical is n-butyraldehyde, followed by C6-C13 aldehydes for plasticizer alcohols, isobutyraldehyde and C12-C18 aldehydes for detergent alcohols. Plasticizer alcohols, including butanols, 2-ethylhexanol and C7-C13 plasticizer oxo alcohols, and, increasingly, 2-propylheptanol, are the largest market for oxo chemicals in all regions; world consumption of plasticizer alcohols is forecast to grow at an average annual rate of 3.8% during 2011–2018. Valeraldehyde is the fastest-growing oxo chemical; world consumption is forecast to grow at an average annual rate of 4.8% during 2011–2018, albeit from a relatively small base. New C5 aldehyde capacity is scheduled to come onstream by 2014 in Western Europe. Most of this valeraldehyde will be captively consumed for 2-propylheptanol. The following pie chart shows world consumption of oxo chemicals:


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Asia (including Japan), Europe and North America are the largest markets for oxo chemicals, accounting for 95% of world demand in 2012. The long-term prospects for oxo chemicals in Western Europe improved considerably during 2005–2008, as consolidations and capacity reductions resulted in improved efficiencies and capacity utilization. The commissioning of plants for 2-propylheptanol and additional isononyl alcohol capacity helped reduce the former reliance on 2-ethylhexanol. Western European consumption of oxo chemicals is forecast to grow at an average annual rate of 1.8% during 2011–2018. Demand for oxo chemicals in the United States is expected to grow moderately, at an average annual rate of 2.8% during 2011–2018.


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Consumption in China and Other Asia (excluding Japan) is expected to grow at 5.4% annually during the same period; China, Singapore, India and Taiwan are the main growth markets in this region. Japanese consumption is forecast to experience 0.3% average annual growth during 2011–2018. Middle Eastern consumption of oxo chemicals is forecast to grow significantly at an average annual rate of 13.0% during 2011–2018, albeit from a small base, largely the result of increased n-butanol/2-ethylhexanol demand for acrylates by 2014. World demand for oxo chemicals recovered in 2010, but stumbled in some regions, including the United States, the eurozone and Japan, in 2011–2012. Largely as a result of strong demand in China and Other Asia (excluding Japan), world consumption of oxo chemicals grew at an average annual rate of just over 4% during 2008–2012.

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2 EH Production

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