Influence of extensive thermal polymerization upon the Raman spectra of vinyl monomers (styrene)

Bortnichuk, A. L.; Stepukhovich, A.D.

doi:10.1007/bf00610540

Cited by 3 publications

(2 citation statements)

References 6 publications

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“…Raman bands at 1005, 1033, 1185, 1200, 1321, 1417, 1498, 1600, and 1629 cm –1 due to the styrene adsorption were observed at room temperature after introducing styrene in Ar while some of the ceria bands (345, 556, 592, and 1714 cm –1 ) were attenuated by the styrene. The observed bands could be assigned to C–H bending of an romatic ring (1185, 1200 cm –1 ), the CH– and CH 2 deformation (1321, and 1417 cm –1 ) C–C stretch of the aromatic ring (1005, 1033, 1498, 1600 cm –1 ), and vinyl CC stretches (1629 cm –1 ). − It is significant that the CC stretching at 1629 cm –1 disappeared at temperatures above 200 °C because this suggests polymerization. Meanwhile, the C–C stretches of aromatic rings (1005, 1498 cm –1 ) increased, the peak at 1600 cm –1 shifted to 1595 cm –1 , and a new band at 1447 cm –1 appeared.…”

Section: Resultsmentioning

confidence: 99%

Role Of CO₂ As a Soft Oxidant For Dehydrogenation of Ethylbenzene to Styrene over a High-Surface-Area Ceria Catalyst

Zhang¹,

Wu²,

Nelson

et al. 2015

ACS Catal.

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Catalytic performance and the nature of surface adsorbates were investigated for high-surface-area ceria during the ethylbenzene oxidative dehydrogenation (ODH) reaction using CO2 as a soft oxidant. The high surface area ceria material was synthesized using a template-assisted method. The interactions among ethylbenzene, styrene, and CO2 on the surface of ceria and the role of CO2 for the ethylbenzene ODH reaction have been investigated in detail by using activity test, in situ diffuse reflectance infrared and Raman spectroscopy. CO2 as an oxidant not only favored the higher yield of styrene but also inhibited the deposition of coke during the ethylbenzene ODH reaction. Ethylbenzene ODH reaction over ceria followed a two-step pathway: ethylbenzene is first dehydrogenated to styrene with H2 formed simultaneously, and then CO2 reacts with H2 via the reverse water gas shift. The produced styrene can easily undergo polymerization to form polystyrene, which is a key intermediate for coke formation. In the absence of CO2, the produced polystyrene transforms into graphite-like coke at temperatures above 500 °C, which leads to catalyst deactivation. In the presence of CO2, the coke deposition can be effectively removed via oxidation with CO2. ABSTRACT: Catalytic performance and the nature of surface adsorbates were investigated for high-surface-area ceria during the ethylbenzene oxidative dehydrogenation (ODH) reaction using CO 2 as a soft oxidant. The high surface area ceria material was synthesized using a template-assisted method. The interactions among ethylbenzene, styrene, and CO 2 on the surface of ceria and the role of CO 2 for the ethylbenzene ODH reaction have been investigated in detail by using activity test, in situ diffuse reflectance infrared and Raman spectroscopy. CO 2 as an oxidant not only favored the higher yield of styrene but also inhibited the deposition of coke during the ethylbenzene ODH reaction. Ethylbenzene ODH reaction over ceria followed a two-step pathway: ethylbenzene is first dehydrogenated to styrene with H 2 formed simultaneously, and then CO 2 reacts with H 2 via the reverse water gas shift. The produced styrene can easily undergo polymerization to form polystyrene, which is a key intermediate for coke formation. In the absence of CO 2 , the produced polystyrene transforms into graphite-like coke at temperatures above 500°C, which leads to catalyst deactivation. In the presence of CO 2 , the coke deposition can be effectively removed via oxidation with CO 2 .

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Section: Resultsmentioning

confidence: 99%

Role Of CO₂ As a Soft Oxidant For Dehydrogenation of Ethylbenzene to Styrene over a High-Surface-Area Ceria Catalyst

Zhang¹,

Wu²,

Nelson

et al. 2015

ACS Catal.

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“…[3][4][5] Other spectroscopic techniques like nuclear magnetic resonance [6] or fluorescence [7,8] have been reported for monitoring polymerization reactions either in homogenous or in heterogeneous reaction media but mainly at the laboratory scale. It has been shown that Raman spectroscopy allowed in situ determination of monomer consumption in free radical polymerization reactions carried out with different processes: several examples have been reported for bulk polymerization and [9][10][11][12][13][14][15] emulsion polymerization [16][17][18] while there is only one example for miniemulsion process. [19] Most of the reported studies monitored the progress of polymerization reaction by continuously following the decrease of a peak corresponding to the double bond of monomers.…”

Section: Introductionmentioning

confidence: 99%

In situ monitoring of styrene polymerization using Raman spectroscopy. Multi‐scale approach of homogeneous and heterogeneous polymerization processes

Brun

Youssef

Chevrel

et al. 2013

J Raman Spectroscopy

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International audienceFree radical polymerization of styrene was monitored in situ by combining Raman spectroscopy to other experimental techniques (gravimetry and rheology). Three different processes were investigated: bulk, emulsion and miniemulsion polymerization. A complete analysis of the evolution of Raman spectrum during the course of reaction showed that a lot of information about molecular dynamics could be extracted and related to chemical phenomena. In addition, we report for the first time the coupling of Raman spectroscopy to a rheometer in order to monitor styrene bulk polymerization both at the scale of chemical bonds and at the scale of macroscopic phenomena (viscosity variation)

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Hollow core-shell particles via NR latex seeded emulsion polymerization

Wichaita

Polpanich

Suteewong

et al. 2016

Polymer

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Influence of extensive thermal polymerization upon the Raman spectra of vinyl monomers (styrene)

Cited by 3 publications

References 6 publications

Role Of CO₂ As a Soft Oxidant For Dehydrogenation of Ethylbenzene to Styrene over a High-Surface-Area Ceria Catalyst

Role Of CO₂ As a Soft Oxidant For Dehydrogenation of Ethylbenzene to Styrene over a High-Surface-Area Ceria Catalyst

In situ monitoring of styrene polymerization using Raman spectroscopy. Multi‐scale approach of homogeneous and heterogeneous polymerization processes

Hollow core-shell particles via NR latex seeded emulsion polymerization

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Influence of extensive thermal polymerization upon the Raman spectra of vinyl monomers (styrene)

Cited by 3 publications

References 6 publications

Role Of CO2 As a Soft Oxidant For Dehydrogenation of Ethylbenzene to Styrene over a High-Surface-Area Ceria Catalyst

Role Of CO2 As a Soft Oxidant For Dehydrogenation of Ethylbenzene to Styrene over a High-Surface-Area Ceria Catalyst

In situ monitoring of styrene polymerization using Raman spectroscopy. Multi‐scale approach of homogeneous and heterogeneous polymerization processes

Hollow core-shell particles via NR latex seeded emulsion polymerization

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Product

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About

Role Of CO₂ As a Soft Oxidant For Dehydrogenation of Ethylbenzene to Styrene over a High-Surface-Area Ceria Catalyst

Role Of CO₂ As a Soft Oxidant For Dehydrogenation of Ethylbenzene to Styrene over a High-Surface-Area Ceria Catalyst