Cyclodehydration of diethylene glycol over Ag-modified Al2O3 catalyst

Sun, Daolai; Wang, Junjie; Yamada, Yoshio; Sato, Satoshi

doi:10.1016/j.apcata.2015.03.047

Cited by 17 publications

(11 citation statements)

References 33 publications

(55 reference statements)

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“…The peaks assigned to Ag metal were observed at Ag loadings higher than 5%, indicating the additive Ag was reduced to metal before the reaction, and worked at a metal state during the reaction. It is possible that Ag also plays another important role for the inhibition of catalytic deactivation, as has been described in our previous studies [24,32,34,35].…”

Section: Characterization Of Catalyst Samplessupporting

confidence: 51%

“…2), where W and F are catalyst weight and flow rate of reactant, respectively. [24], dehydration of tetrahydrofurfuryl alcohol into 3,4-2H-dihydropyran [33], and cyclodehydration of diethylene glycol to 1,4-dioxane [34], respectively. In these processes, H 2 carrier gas is required for inhibiting the catalytic deactivation.…”

Section: Resultsmentioning

confidence: 99%

“…As shown in Fig. 5, a weight loss below 200 o C is considered to be attributed to the desorption of H 2 O, and a weight loss can be observed at a temperature range from 200 to 600 o C, which is considered to be caused by the decomposition of coke [34]. The order of the amount of coke in the used catalysts was 3Ag- (Fig.…”

Section: Characterization Of Catalyst Samplesmentioning

confidence: 93%

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Vapor-phase dehydration of C4 unsaturated alcohols to 1,3-butadiene

Sun

Arai

Duan

et al. 2017

Applied Catalysis A: General

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Vapor-phase dehydration of C4 unsaturated alcohols such as 3-buten-1-ol, 2-buten-1-ol and 3-buten-2-ol were performed to produce 1,3-butadiene over various solid catalysts including ordinary solid acid catalysts such as Al 2 O 3 , SiO 2-Al 2 O 3 , and TiO 2 and basic rare earth metal oxides such as Yb 2 O 3 and CeO 2. In the reaction of 3-buten-1-ol, 1,3-butadiene could not be selectively produced because the acid catalysts decomposed 3-buten-1-ol into propylene. In contrast to the acid catalysts, CeO 2 inhibited the decomposition of 3-buten-1-ol and showed a relatively high performance for the formation of 1,3-butadiene. In the dehydration of 2-buten-1-ol and 3-buten-2-ol, however, acid catalysts were effective for the formation of 1,3-butadiene. Among the tested catalysts, commercial SiO 2-Al 2 O 3 showed a relatively high catalytic performance, although it deactivated rapidly. We prepared a series of SiO 2 /Al 2 O 3 catalysts by depositing SiO 2 species onto Al 2 O 3 support, and the SiO 2 /Al 2 O 3 with a SiO 2 content of 10 wt.% showed more stable catalytic activity than the commercial SiO 2-Al 2 O 3. Furthermore, modification of SiO 2 /Al 2 O 3 with Ag at a loading of 3-5 wt.% was found to be efficient for inhibiting the coke formation and improving the catalytic stability of SiO 2 /Al 2 O 3 in the dehydration of both 2-buten-1-ol and 3-buten-2-ol under hydrogen flow conditions.

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Section: Characterization Of Catalyst Samplessupporting

confidence: 51%

Section: Resultsmentioning

confidence: 99%

Section: Characterization Of Catalyst Samplesmentioning

confidence: 93%

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Vapor-phase dehydration of C4 unsaturated alcohols to 1,3-butadiene

Sun

Arai

Duan

et al. 2017

Applied Catalysis A: General

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“…ZrO 2 and γ-Al 2 O 3 are widely used as acid-base catalysts[29,[31][32], and we have also confirmed their acid-base properties by NH 3 -and CO 2 -TPD analysis in our previous study[33]. Thus, it is reasonable that the base sites in ZrO 2 and γ-Al 2 O 3 catalyze the further oligomerization of ALs, and that results in the low…”

supporting

confidence: 81%

“…This indicates that the silanol group is exchanged with a silyl group through the silylation of SiO 2 -Q3, and that trimethylsilyl groups are successfully introduced on the catalyst surface. In the spectra of the silylated SiO 2 -Q3 and used SiO 2 -Q3, the peaks assigned to the stretching vibration of C-H in CH 2 and CH 3 were observed at 2854 and 2924 cm -1 , respectively [29]. The peak at 1745 in the spectra of the used SiO 2 -Q3 was attributed to the stretching vibration of a C=O group [30].…”

Section: Characterization Of the Catalystsmentioning

confidence: 96%

Efficient formation of angelica lactones in a vapor-phase conversion of levulinic acid

Sun

Takahashi

Yamada

et al. 2016

Applied Catalysis A: General

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Vapor-phase lactonization of levulinic acid to produce angelica lactones, which include α-, β-and γform isomers, was performed in fixed-bed down-flow glass reactors over various oxide catalysts. SiO 2 and SiO 2-Al 2 O 3 showed relatively high catalytic activity. The lactonization of levulinic acid to angelica lactones was found to be an endothermic equilibrium reaction, and the pressure equilibrium constant was calculated to be 0.2 atm at 275 o C. High temperatures and reduced pressures were efficient for shifting the equilibrium from levulinic acid to angelica lactones, while the suitable reaction temperature was estimated to be 275 o C because temperatures higher than 275 o C decreased the selectivity to angelica lactones. The highest angelica lactones yield of 87.5% was achieved at a levulinic acid conversion of 95.3% over SiO 2 under reduced pressure conditions of ca. 5 kPa at 275 o C. IR, NH 3-TPD and TG analyses were performed for characterizing the catalysts used after the reactions together with a silylated SiO 2 prepared for studying the active species on SiO 2. The silanol groups of SiO 2 with weak acidity were proposed to be the active species.

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