TY - JOUR
T1 - Mechanistic understanding of methanol carbonylation
T2 - Interfacing homogeneous and heterogeneous catalysis via carbon supported Ir–La
AU - Hensley, Alyssa J.R.
AU - Zhang, Jianghao
AU - Vinçon, Ilka
AU - Pereira Hernandez, Xavier
AU - Tranca, Diana
AU - Seifert, Gotthard
AU - McEwen, Jean Sabin
AU - Wang, Yong
N1 - Publisher Copyright:
© 2018 Elsevier Inc.
PY - 2018/5
Y1 - 2018/5
N2 - The creation of heterogeneous analogs to homogeneous catalysts is of great importance to many industrial processes. Acetic acid synthesis via the carbonylation of methanol is one such process and it relies on a difficult-to-separate homogeneous Ir-based catalyst. Using a combination of density functional theory (DFT) and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, we determine the structure and mechanism for methanol carbonylation over a promising single-site Ir–La/C heterogeneous catalyst replacement. Here, the Ir center is the active site with the acetyl-Ir complex being a rate controlling intermediate. Furthermore, the La both atomically disperses the Ir and acts as a Lewis acid site. In fact, the La promoter in the Ir–La/C catalyst was found to behave similarly to homogeneous promoters by abstracting an iodine from the Ir center and accelerating the CO insertion step. Overall, this work provides key insight into the atomistic nature of the Ir–La/C single-site catalyst and allows for the further design and optimization of single-site heterogeneous catalysts.
AB - The creation of heterogeneous analogs to homogeneous catalysts is of great importance to many industrial processes. Acetic acid synthesis via the carbonylation of methanol is one such process and it relies on a difficult-to-separate homogeneous Ir-based catalyst. Using a combination of density functional theory (DFT) and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, we determine the structure and mechanism for methanol carbonylation over a promising single-site Ir–La/C heterogeneous catalyst replacement. Here, the Ir center is the active site with the acetyl-Ir complex being a rate controlling intermediate. Furthermore, the La both atomically disperses the Ir and acts as a Lewis acid site. In fact, the La promoter in the Ir–La/C catalyst was found to behave similarly to homogeneous promoters by abstracting an iodine from the Ir center and accelerating the CO insertion step. Overall, this work provides key insight into the atomistic nature of the Ir–La/C single-site catalyst and allows for the further design and optimization of single-site heterogeneous catalysts.
KW - Attenuated total reflectance-Fourier transform infrared spectroscopy
KW - Density functional theory
KW - Ir–La complex
KW - Methanol carbonylation
KW - Promoter effects
KW - Single-site heterogeneous catalyst
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U2 - 10.1016/j.jcat.2018.02.022
DO - 10.1016/j.jcat.2018.02.022
M3 - Article
AN - SCOPUS:85044949364
SN - 0021-9517
VL - 361
SP - 414
EP - 422
JO - Journal of Catalysis
JF - Journal of Catalysis
ER -