TiO2-supported heteropoly acids for low-temperature synthesis of dimethyl ether from methanol

TiO2-supported heteropoly acid catalysts for dehydration of methanol to dimethyl ether: relevance of dispersion and support interaction

“…This process leads to the formation of the relatively stable hexahydrated structures, H 3 PW 12 O 40 ·6H 2 O and H 4 SiW 12 O 40 ·6H 2 O, in both the bulk and the supported HPAs. 23,45,46 In such hexahydrated structures, the water of crystallization is located 23 This weight loss is not observed for the catalysts with HPA loading ≤0.9 KU nm −2 , probably due to the detection limit of the thermobalance equipment. At higher temperatures (T >700 K), a small weight loss is observed for the bulk and highly loaded catalysts.…”

“…The Raman bands of the dehydrated heteropoly acids tend to become less intense and broader than those recorded for hydrated HPAs. 23 As a consequence, the assignment of the Raman bands in the spectra of the dehydrated supported catalysts containing low amounts of HPA is not straightforward. The Raman spectrum of the bulk HPW shows two intense bands at 1007 and 991 cm −1 , which are attributed to the symmetric and asymmetric stretching modes of terminal WO t .…”

“…Recently, it has been reported that heteropoly acids (HPAs) exhibit very high catalytic activities for the dehydration of alcohols. [19][20][21][22][23][24][25] In fact, some HPAs exhibit higher reaction rates than conventional solid acid catalysts. 11,20,24 In a recent study, 23 we reported that TiO 2 -supported tungstosilicic acid IJH 4 SiW 12 O 40 ) is a very active catalyst for methanol dehydration even at temperatures as low as 413 K, reaching conversions of ca.…”

Methanol Conversion into Dimethyl Ether on the Anatase TiO2(001) Surface

“…[1][2][3][4] As ar epresentative and versatile oxide catalyst, TiO 2 has been explored as catalysts for methanol conversion. [5,6] Thephotocatalytic conversion of methanol over TiO 2 has been ah ot topic in photocatalysis.[7] These reports have motivated fundamental studies of methanol adsorption and reaction on TiO 2 surfaces that mostly employed TiO 2 single crystals as amodel surfaces. [8][9][10][11][12][13][14][15][16][17][18] Among various types of TiO 2 facets anatase TiO 2 (001) is of particular interest.…”

Synthesis, Characterization and Catalytic Polymerization of N-Methyl Imidazolium Phosphotungstic Catalyst

“…Heteropoly acids (HPAs) have attracted significant attention because of their high acidity and favorable redox properties [1][2][3][4][5][6][7][8]. Among different HPAs, Keggin type (such as phosphotungstic acid) are well known and widely studied compounds for various catalytic applications, such as Friedel-Craft's alky-lation, acylation, oxidation, hydration of alkenes, esterification, transesterification, and carbonylation [9][10][11][12][13][14].…”