Operando ATR-FTIR analysis of liquid-phase catalytic reactions: can heterogeneous catalysts be observed?

Mul, Guido; Hamminga, Gerben M.; Moulijn, Jacob A.

doi:10.1016/j.vibspec.2003.07.004

Cited by 52 publications

(53 citation statements)

References 16 publications

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“…Both the esterification reaction of hexanoic acid (95+%, Merck) and 1-octanol (95+%, Baker) and the etherification reaction of 1-octanol were performed in a reflux slurry configuration, as was reported in [35]. The kinetics of both reactions was either studied in cumene (98%, Acros) at 427 K, or in n-decane (95+%, Merck) at 447 K. The pressure was atmospheric, the total reaction volume was 200 ml containing 0.4 mol/l acid and alcohol, and 1.0 g of a Nafion on silica composite consisting of 13% w/w Nafion, respectively.…”

Section: Methodsmentioning

confidence: 99%

“…The ATR FT-IR equipment used for on-line reaction monitoring and the apparatus applied for "off-line" GCanalysis have been described in detail in a previous publication [35]. Also the processing of the obtained ATR-spectra is described in this publication.…”

Section: Kinetic Measurementsmentioning

confidence: 99%

“…Only few papers on real-time in situ ATR FT-IR spectroscopy have been dedicated to kinetic and mechanistic studies of heterogeneous liquid-phase catalytic reactions at relative low pressures [32][33][34][35][36][37]. In these studies, however, no evidence was found of reactants, reaction intermediates or products interacting with or adsorbed on the catalyst surface.…”

Section: Introductionmentioning

confidence: 99%

“…In a previous publication we have applied real time in situ ATR FT-IR spectroscopy for analysis of the esterification and etherification reactions of 1-octanol and hexanoic acid (see figure 1) using Nafion/silica catalysts, with the main result being the appearance of IR bands in the spectra that were tentatively assigned to interactions of one the reactants (alcohol) with the solid catalyst particles [35]. The present study aims to further evaluate the nature of the intermediate species adsorbed on the heterogeneous catalysts, and the reason behind the appearance of the accompanying absorptions in the ATR-spectra, including particle size effects.…”

Section: Introductionmentioning

confidence: 99%

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Reaction Kinetics and Intermediate Determination of Solid Acid Catalysed Liquid-phase Hydrolysis Reactions: A Real-time in situ ATR FT-IR Study

2006

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The appearance of catalyst-reactant interactions observed in on-line ATR FT-IR spectra of Nafion/silica catalysed esterification and etherification reactions of 1-octanol was investigated. It was assessed by variation of catalyst and solvent that the catalyst-reactant band is a result of the reaction of silica with 1-octanol, yields Si-O-R functionalities. Based on off-line TPD-MS and TGA characterisation of the used solid catalyst powder, the formation of Si-O-R linkages on the SiO 2 surface was confirmed. This demonstrates conclusively that in specific liquid-phase reactions, on-line analysis of intermediate species adsorbed on heterogeneous catalysts is possible. Using on-line particle analyzers, it was assessed that the absorptions were not the result of severe attrition of the catalyst particles in the course of the reaction, but apparently the result of apolar interactions of the particles with the diamond crystal.

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Section: Methodsmentioning

confidence: 99%

Section: Kinetic Measurementsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Reaction Kinetics and Intermediate Determination of Solid Acid Catalysed Liquid-phase Hydrolysis Reactions: A Real-time in situ ATR FT-IR Study

2006

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“…In particular, the ATR-FTIR technique operating in the MIR spectral region has proved suitable for both kinetic and mechanistic studies. Since several years ATR probes have become commercially available for in situ FTIR studies of liquid-phase reactions under working conditions [e.g., [1][2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Mid-Infrared Monitoring of Gas-Liquid Reactions in Vitamin D Analogue Synthesis with a Novel Fiber Optical Diamond ATR Sensor

Bentrup

Küpper²,

Budde³

et al. 2006

Chem. Eng. Technol.

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A novel mid-infrared optical sensor enabling in situ ATR measurements was applied to investigate several steps of a vitamin D analogue synthesis. The probe based on silver halide fibers coupled to a diamond prism was connected to a conventional FTIR spectrometer with internal MCT detector. All steps of the reaction were monitored by real-time in situ FTIR measurements. The steps carried out were the dissolution of SO 2 in a CH 2 Cl 2 /CH 3 OH solvent mixture as well as the addition of SO 2 to a vitamin D analogue, the subsequent ozonation of the double bond in the SO 2 addition product, and the following reduction of the formed hydroperoxide with triphenylphosphine. The dissolving process of SO 2 and the addition of SO 2 to the vitamin D analogue were monitored by changing the characteristic m as (SO 2 ) and m s (SO 2 ) modes of dissolved and incorporated SO 2 . It was found that during ozonation of the SO 2 addition product the formation of hydroperoxide is accompanied by the simultaneous formation of the corresponding aldehyde identified by the typical m(C=O) band at 1720 cm -1. Extended ozone exposure favors the formation of the corresponding acid detected by an additional carbonyl band at lower wavenumbers. During the reaction with triphenylphosphine the increasing intensity of the aldehyde band and the appearance of the m(P=O) mode of the formed triphenylphosphine oxide indicate the progressive reduction of hydroperoxide. The hydroperoxide band disappears completely during the reaction whereas the m as (SO 2 ) band remains unaffected.

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Infrared Spectroscopy on Powder Catalysts

Stavitski¹

2013

In‐situ Characterization of Heterogeneous Catalysts

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Operando ATR-FTIR analysis of liquid-phase catalytic reactions: can heterogeneous catalysts be observed?

Cited by 52 publications

References 16 publications

Reaction Kinetics and Intermediate Determination of Solid Acid Catalysed Liquid-phase Hydrolysis Reactions: A Real-time in situ ATR FT-IR Study

Reaction Kinetics and Intermediate Determination of Solid Acid Catalysed Liquid-phase Hydrolysis Reactions: A Real-time in situ ATR FT-IR Study

Mid-Infrared Monitoring of Gas-Liquid Reactions in Vitamin D Analogue Synthesis with a Novel Fiber Optical Diamond ATR Sensor

Infrared Spectroscopy on Powder Catalysts

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