Butylene hydroformylation

A severe drawback of the process arises from the limited solubility of olefins in water, which restricts the process to propylene and butylenes hydroformylation. Figure 6.14.5 shows the dependence of olefin solubility in water as a function of the number of carbon atoms. 

Note that for a low olefin concentration in the catalyst phase the reaction rate is first order in olefin - thus the reaction rate in the Ruhrchemie/Rhone-Poulenc process is severely limited by the low olefin concentration. As a consequence, even for propylene hydroformylation the Ruhrchemie/Rhone-Poulenc process requires a relatively large reactor and a relatively high rhodium inventory. For butylene hydroformylation, the process approaches the margin of economic operability, and for the hydroformylation of even higher olefins it becomes unfeasible because of the limited olefin solubility. Note that a significant amount of mechanical (in fact electrical) energy has to be invested in the Ruhrchemie/Rhone-Poulenc process for intense stirring to provide the necessary interphase in the biphasic system so as to operate the system free of mass transfer limitations. 

Propjiene (qv) [115-07-1] is the predominant 0x0 process olefin feedstock. Ethylene (qv) [74-85-1J, as well as a wide variety of terminal, internal, and mixed olefin streams, are also hydroformylated commercially. Branched-chain olefins include octenes, nonenes, and dodecenes from fractionation of oligomers of C —C olefins as well as octenes from dimerization and codimerization of isobutylene and 1- and 2-butenes (see Butylenes). 

Hydroformylation. Hydroformylation of aEyl alcohol is a synthetic route for producing 1,4-butanediol [110-63-4] a raw material for poly(butylene terephthalate), an engineering plastic (qv) many studies on the process have been carried out. 

Butylene isomers also can be expected to show significant differences in reaction rates for metaHation reactions such as hydroboration and hydroformylation (addition of HCo(CO). For example, the rate of addition of di(j -isoamyl)borane to cis-2-huX.en.e is about six times that for addition to trans-2-huX.en.e (15). For hydroformylation of typical 1-olefins, 2-olefins, and 2-methyl-l-olefins, specific rate constants are in the ratio 100 31 1, respectively. 

Amyl alcohols occur in eight isomeric forms and have the empirical formula CjHnOH. All are liquids at ambient conditions except 2,2-dimethylpropanol (neopentyl alcohol), which is a solid. Almost all amyl alcohols are manufactured in the United States by the hydroformylation of butylenes. Yeast fermentation processes for ethanol yield small amounts of 4-methyl-l-butanol (isoamyl alcohol) and 2-methyl-1-butanol (active amyl alcohol, scc-butyl-carbinol) as fusel oil. However, when the amino acids leucine and isoleucine are added to sugar fermentations by yeast, 87% and 80% yields of 4-methyl-l-butanol and 2-methyl-l-butanol, respectively, are obtained (Fieser and Fieser, 1950). These reactions are not suitable for commercial applications because of cost, but they do indicate the close structural relationship between these C5 amino acids and the C5 alcohols. The reactions occur under nitrogen-deficient conditions. If a nitrogen source is readily available, the production of the alcohols is lowered considerably. 

Ziegler (organoaliiminum) oxo (hydroformylation) aldol paraffin oxidation Guerbet Total ethylene, triethylaluminum olefins based on ethylene, propylene, butylene, or paraffins //-butyraldehyde paraffin hydrocarbons lower primary alcohols primary C —Clg linear alcohols primary alcohols 2-ethylhexanol secondary alcohols branched primary alcohols 0.3 4.2 a 0.2 b 4.7... 

Petrochemical alcohols are also produced via the oligomerization of propylene and butylene, followed by hydroformylation of the olefine to the alcohol. 

Another method of producing a nonyl alcohol, which has gained predominance in the past few years, is by the dimerization process. In this process n-butylenes react to form an octene. Then through hydroformylation the 8-carbon olefin is converted to a nonyl alcohol (eq. 6). This alcohol has specific branching and some linearity that provides the corresponding ester with improved properties over esters made from isononyl alcohol. 

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