Boreskov Institute of Catalysis of the Siberian Branch of Russian ...

OP-I-19The conversion and selectivity to decomposition products observed for the reaction of3-HPA and 2-HOAC are also strongly dependent on the texture and acidity of solidphosphoric acids. With the increase of intrinsic acidity and the reactions temperature the risein conversion was observed. Additionally the decomposition C-C bond of glycerol and2-HOAC and depositions of cokes was found. (Fig. 1a-c). This is due to the furtherdecompositions of carbonyl compounds which are thermodynamically favourable at highertemperature.Conversion (%)a350°C100325°CTiO 2-PO 480275°C6040 250°C20100b80604020γ-Al 2O 3-PO 4γ-Al 2O 3-PO 4bimodalTiO 2-PO 4SAPO-34SAPO-11me: 44 CO 2MS-Intensity (a.u.)c540°CSAPO-34200 400 600 800SAPO-11γ-Al 2O 3-PO 4410°C0TiO02-PO 42 3 4 5 62-HOAC 3-HPA Total Acidity (μmol NH 3/m 2 )200 400 600 800Temperature (°C)Fig. 1a-c. Conversion of 2-HOAC and 2-HPA over TiO 2 -PO 4 at different temperatures (a) and differentcatalysts at 275°C (b) and the amount of carbon deposits (c) over catalysts after reaction with 2-HOAC at 310°Cin the presence of water (DTA-MS Analysis).Conclusions. Supported phosphates and SAPOs showed the different activity for the gasphasedehydration of glycerol and degradation of 2-hydroxy acetone and 3-hydroxy propionaldehydein the presence of water. The total acidity, the texture of the supported phosphatesand the reactions temperature strongly influenced both conversion and distribution of theproducts. The experimental data showed that in the presence of the acidic catalysts 2-HOACwas stable until 240°C. In contrast, 3-HPA was dehydrated to acroleine and was subject ofcondensation to cyclic C 6 compounds already at 120°C. The side products were identifiedwith GC-MS. Deactivation was observed for all of acid catalyst, but a oxidative treatmentwith air at the reactions temperature about 450°C was found to be sufficient to regenerate thedeactivated catalysts and recovery of acidity and activity.References:1. A. Behr, J. Eilting, et al., Green Chemistry, 10 (2008) 13.2. S.H. Chai, H.P. Wang, Yu Liang, Bo-Quing Xu,, J. Catal. 250 (2007) 342.3. A. Neher, T. Hass, D. Arntz, H. Klenk, US Pat. 5387720 (1995) Degussa AG.4. M.R. Nimlos, S.J. Blanksby, J. Phys. Chem. A, 110, (2006) 6145.63