Kinetics of the hydroformylation of soybean oil by ligand‐modified homogeneous rhodium catalysis

Abstract

The kinetics and mechanism of the hydroformylation of soybean oil by homogeneous ligand-modified rhodium catalysts were investigated at 70-130°C and 4000-11,000 kPa. The effects of reaction rates on systematic variations in reaction parameters were evaluated in order to develop an industrial process to convert vegetable oils to polyaldehydes. The activation energies in the presence of triphenylphosphine (Ph 3 P) (61.1 ± 0.8 kJ/mol) (mean ± SD) and triphenyl phosphite [(PhO) 3 P] (77.4 ± 5.0 kJ/mol) were determined. The catalyst was deactivated at temperatures higher than 100°C. An evaluation of the effects of the reaction parameters on initial rates yielded the rate laws for Ph 3 P {rate = k [olefin][Rh(CO) 2 Acac] 1.1 [Ph 3 P] −0.5 (pH 2 + pCO) 1.4 , where Rh(CO) 2 Acac is (acetylacetonato)dicarbonylrhodium (I)} and (PhO) 3 P {rate = [olefin] [Rh(CO) 2 Acac] 1.2 [(PhO) 3 P] −0.8 (pH 2 + pCO) 0.9 at total pressures lower than 7000 kPa, and rate = [olefin] [Rh(CO) 2 Acac] 1.2 [(PhO) 3 P] −0.8 (pH 2 + pCO) 1.7 at total pressures higher than 7000 kPa}.Strategic research in the development of new technologies for the conversion of biobased feedstocks such as vegetable oils to value-added products is important for economic growth in the environmentally conscious, yet highly competitive, global economy. The chemical composition of vegetable oils consists of TG esters with three dominant FA, oleic, linoleic, and linolenic acids having internal double bonds. Hydroformylation, commonly known as the oxo process, is an environmentally friendly process by which those TG can be converted to polyaldehydes (1-4). Whereas the kinetics and mechanism of simple olefin hydroformylation over phosphine-or phosphitemodified rhodium catalysts have been reported (5-16), the effects of reaction parameters on the reaction rates of unsaturated FA esters, TG, or vegetable oils have not been extensively investigated (17)(18)(19).We now report the results of a kinetic investigation of the conversion of soybean oil to polyaldehydes by the hydroformylation reaction using homogeneous rhodium catalysis under the reaction conditions relevant to industrial processes. Scheme 1 shows the hydroformulations of a model TG ester having one (oleic) and two (linoleic) double bonds. EXPERIMENTAL PROCEDURESThe iodine value of soybean oil (ADM, Decatur, IL) was measured, and the oil was used as received. Acetone (HPLC grade), acetonitrile (HPLC grade), triphenylphosphine (Ph 3 P; 99%), and triphenyl phosphite [(PhO) 3 P; 99+%] were purchased from Acros Organics (Fairlawn, NJ), as was toluene (HPLC grade, Fisher, Fairlawn, NJ); these were used as received. FTIR measurements were made as thin films of liquid samples on NaCl windows by a PerkinElmer (Spectra 1000) spectrometer. HPLC analysis was performed by using a Waters 1525 binary pump, a Waters 2410 refractive index, and Waters 2487 dual λ absorbance detectors.A detailed description of the hydroformylation reactor and the kinetic procedure are reported elsewhere (3). The experimental setup used to evaluate t...

Highly functional polyols from castor oil for rigid polyurethanes

“…Currently only few bio-based isocyanates are commercially available and the main focus has been designing polyols for specific polyurethane applications [4]. Preparation of polyurethanes from renewable raw materials is important from ecological, economic and technological standpoints [5][6][7][8][9][10][11][12][13][14]. Castor oil is a natural polyol with many applications in the polymer industry, particularly in polyurethanes (PU) [15][16][17][18].…”

Hydroaminomethylation of oleochemicals: A comprehensive overview

“…Countless functionalizations of oleochemicals have already been implemented [5]. The carbon-carbon double bonds of fatty acids, fatty esters, and triglycerides have especially been converted into epoxy [6][7][8][9][10][11][12][13], hydroxyl [14][15][16][17][18][19][20][21], formyl [22][23][24][25][26][27], acrylate [28][29][30], or crossmetathesis derivatives [31][32][33], to name only a few. The functionalization of the carbon-carbon double bonds by amino groups is also of great interest.…”

Soy-Based Polyols and Polyurethanes

“…Cobalt-catalyzed hydroformylation can be conducted at 120 °C and 28 MPa (4000 psi) of total syngas pressure. Depending on the reaction conditions and the type of catalysts used, polyols of different degrees of conversion (up to 95%) can be produced Kandanarachchi et al, 2002;Petrovic et al, 2008). In a different study, the use of nickel as a catalyst a higher efficiency in producing polymers with higher viscosity in a shorter time than when comparing with reactions without catalyst (Mello, et al, 2015).…”