Surface Chemistry and Catalytic Properties of Boron Phosphate: 1. Surface Area and Acidity

Abstract

A B S T R A C T Surface properties o f the dehydration catalyst, boron phosphate ( B P)

Metal phosphate catalyzed dehydration of sorbitol under hydrothermal conditions

“…Table 2 illustrates the BET surface and the pore size distribution for the investigated metal phosphates obtained by the N 2 adsorption-desorption data by means of an ASAP 2000 instrument. The differences between the physical features of the uncalcined and calcined BP catalysts are more evident when the calcination temperatures are higher than 200 • C. An important change in pores size happened when BP has been calcined at 600 • C. It was shown that the surface area of BP increases with pretreatment temperature up to the maximum temperature (450 • C), and afterwards decreases [31,32]. The increase of the total pore volume and of the average pore radius with pretreatment temperature has been reported [33], but in our case this happened up to 400 • C; but in our case higher temperatures result in a decrease of both surface properties.…”

“…The increase of the total pore volume and of the average pore radius with pretreatment temperature has been reported [33], but in our case this happened up to 400 • C; but in our case higher temperatures result in a decrease of both surface properties. Moffat and Goltz [31] presumed that the increase in surface area on heating may be due to the evolution of water from the bulk of the solid during the heating and evacuation process. The transfer of this water from the interior to the surface of the solid could lead to the production of additional porous structure.…”

“…A different distribution of the reactivated acid centers than that of BP is obtained at 180 • C, too. Furthermore, a calcination temperature of 200 • C is not sufficient for water inclosed in the bulk to remove during calcination and some pores are blocked [31] (S BET decreases). This fact could explain the lower activity of It is interesting that differences between the performances of the calcined BP and BP itself occur in the first 2 h. After 24 h the results of the calcined form are quite similar with those obtained by BP uncalcined.…”

Direct conversion of cellulose into C6 alditols over Ru/C combined with H+-released boron phosphate in an aqueous phase

“…Boron phosphate is regarded as an acidic catalyst, which contains both a Brønsted acidic center and Lewis acidic center its surface. [31][32][33][34][35] It has been used for the dehydration reaction of alcohols 36 and isomerization reactions. 37 But it has never been used in the hydrolytic hydrogenation of cellulose.…”

Surface Chemistry and Catalytic Properties of Boron Phosphate: Ii. A Note on the Formation of Paramagnetic Species With Adsorbed Aromatic Compounds

“…Earlier work (1) from this laboratory has demonstrated that acidic sites are present on the surface of boron phosphate (BP). I t is of interest to attempt to demonstrate whether such acidity is of the Bronsted or Lewis type.…”