Isononyl alcohol, manufacture

Mitsubishi Kasei introduced a process to manufacture isononyl alcohol, an important PVC (polyvinyl chloride) plasticizer, via the hydroformylation of octenes (a mixture of isomers produced by dimerization of the C4 cut of naphtha cracker or FCC processes).95 First a nonmodified rhodium complex exhibiting high activity and selectivity in the formation of the branched aldehyde is used. After the oxo reaction, before separation of the catalyst, triphenylphosphine is added to the reaction mixture and the recovered rhodium-triphenylphosphine is oxidized under controlled conditions. The resulting rhodium-triphenylphosphine oxide with an activity and selectivity similar to those of the original complex, is recycled and used again to produce isononanal. 

Application The Dimersol-X process transforms butenes to octenes, which are ultimately used in the manufacture of plasticizers via iso-nonanol (isononyl alcohol) and diisononyl phthalate units. 

Hydroformylation is also used for the manufacture of isononyl alcohol and other long-chain alcohols. Isononyl alcohol is made by first hydroformylating 1-octene to isononaldehyde and then hydrogenating the latter. The long-chain alcohols ( 10 to 20 carbon atoms) are used... 

The main uses of 1-butene, 1-hexene, and 1-octene are in the manufacture of linear low-density polyethylene (LLDPE) (see Section 6.1.1). Butene is also used in the manufacture of solvents such as methyl ethyl ketone or secondary butyl alcohol. Apart from LLDPE, 1-octene is used in the manufacture of isononyl alcohol (see Section 5.2). 

These plasticizers can be further grouped in a number of ways one convenient distinction is into general purpose and speciality plasticizers. General purpose types include the three phthalates di-2-ethylhexyl phthalate (DEHP or DOP), di-isononyl phthalate (DINP) and di-isodecyl phthalates (DIDP). These are the esters of phthalic anhydride with the alcohols 2-ethylhexanol, iso-nonanol and isodeconal respectively, and they account for about 75% of plasticizer usage in Western Europe. Other phthalates are also manufactured, but find use more in applications where specific properties are required. 

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