fulltext.study @t Gmail

Phosphoric acid intercalated Mg–Al hydrotalcite-like compounds for catalytic carboxylation reaction of methanol in a continuous system

Paper ID Volume ID Publish Year Pages File Format Full-Text
39383 45821 2015 7 PDF Available
Title
Phosphoric acid intercalated Mg–Al hydrotalcite-like compounds for catalytic carboxylation reaction of methanol in a continuous system
Abstract

•Mg–Al HTs with intercalated phosphate are prepared by co-precipitation.•These solids catalyze the thermodynamically unfavoured carboxylation reaction.•They improve the low activity of others reported heterogeneous catalysts.•Positive effect in activity of high P/Mg molar ratio and ultrasonic-treatment.•The selectivity depends on the temperature due to the formation of DME.

Mg–Al-hydrotalcite-like catalysts (HTlcs) with different amount of P/Mg molar ratio were prepared via co-precipitation method and calcined at 450 °C. The synthesized catalysts were tested in the direct-carboxylation reaction of methanol in gas phase in a continuous system such as chemical route for CO2 valorization. Activities around 2% with total selectivity towards the dimethyl carbonate (DMC) was obtained at moderate temperatures (150 °C) with both Mg/Al mixed oxides (HTO) and phosphated Mg/Al mixed oxides (HTc-9c). Even though the conversion increased until 16% at higher temperatures (200 °C), the selectivity with both catalysts (HTO and HTc-9c) decreased due to the decomposition of DMC to dimethyl ether (DME). Nevertheless, the catalyst with P showed less DMC decomposition and a higher selectivity towards the desired product. This is explained by the presence of orthophosphate species bonded to the Al3+ metals of the HTs (OP(OAl)3) which give to the catalyst a higher structural stability and specific acid properties.In addition, the solids were characterized in-depth by XRD, ICP, NH3-TPD, FTIR, Raman, 27Al and 31P MAS NMR spectroscopy and SEM.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (76 K)Download as PowerPoint slide

Keywords
Mg–Al layered double hydroxides; Phosphate species; 27Al MAS NMR; 31P MAS NMR; TPD; SEM; Carboxylation reaction; Dimethyl carbonate; Acid–base bifunctional catalyst
First Page Preview
Phosphoric acid intercalated Mg–Al hydrotalcite-like compounds for catalytic carboxylation reaction of methanol in a continuous system
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us
Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 493, 5 March 2015, Pages 142–148
Authors
, , , ,
Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us