P3In-depth study of glycerol e<strong>the</strong>rification on Cs ion-exchanged zeolitesYuni K. Krisn<strong>and</strong>i 1 , Marek Checinski 2 , Reinhard Eckelt 2 , Andre<strong>as</strong> Martin 2 , Manfred Richter 21 Dept. Chemistry, Faculty of Math.& Science, University of Indonesia, Depok 16424 Indonesia,2 Leibniz-Institut für Katalyse e.V. an der Universität Rostock, Außenstelle Berlin,Richard-Willstätter-Str. 12, D-12489 BerlinGlycerol is an abundant by-product of biodiesel production, <strong>and</strong>, hence, its conversion to attractiveconsumer products like diglycerol is desirable. Cesium modified solids are reported [1] to be apromising catalyst cl<strong>as</strong>s <strong>for</strong> glycerol e<strong>the</strong>rification, but <strong>the</strong> role <strong>and</strong> fate of cesium during reaction isstill under discussion. The present work centers on <strong>the</strong> influence of <strong>the</strong> zeolite structure on <strong>the</strong>catalytic properties of Cs ion-exchanged samples with focus on diglycerol distribution <strong>and</strong> factorsthat govern <strong>for</strong>mation of <strong>the</strong>se target products. The work benefits from preceding reports ofBarrault et al. [2,3].Commercial zeolite samples of MFI, BEA, FAU structure type were used <strong>for</strong> ion exchange with 0.4M of CsNO 3 or Cs-acetate solution (0.02 g zeolite/ml solution, 60 °C, 24 h, under stirring).Characterization of <strong>the</strong> solids comprised XRD, XRF, SEM, N 2 adsorption <strong>and</strong> <strong>the</strong>rmal analysis.Glycerol e<strong>the</strong>rification w<strong>as</strong> carried out in gl<strong>as</strong>s-reactor equipped with a mechanical stirrer in <strong>the</strong>presence of 2 wt.% of catalyst. Water <strong>for</strong>med during reaction w<strong>as</strong> evaporated <strong>and</strong> condensed. Thereaction w<strong>as</strong> per<strong>for</strong>med at 260 °C <strong>for</strong> 8 <strong>and</strong> 24 h, respectively, with 50 g of glycerol under Arflushing of 50 ml/min. Reagents <strong>and</strong> products were analyzed after silylation [4] by GC. Details willbe given elsewhere [5]. DFT-calculations (6-311(2d2p)/B3LYP) were per<strong>for</strong>med on neutral <strong>and</strong>anionic con<strong>for</strong>mational glycerol <strong>and</strong> diglycerol isomers to underst<strong>and</strong> experimentally observedisomer distributions.Activity (glycerol conversion after 8 h reaction time) w<strong>as</strong> found to be in <strong>the</strong> order of Cs-X > Cs-Y >Cs-USY > Cs-beta > Cs-ZSM-5 with 63 % <strong>and</strong> 5 % conversion over Cs-X <strong>and</strong> Cs-ZSM-5,respectively. XRD <strong>and</strong> SEM analysis of spent catalysts proved that <strong>the</strong> Cs-Y <strong>and</strong> Cs-X zeolitessuffered a structural collapse during reaction (most severe <strong>for</strong> Cs-X) with rele<strong>as</strong>e of Cs intosolution (<strong>as</strong> confirmed by XRF). This explains why <strong>the</strong> activity found <strong>for</strong> Cs-X resembled that of <strong>the</strong>homogenous CsHCO 3 catalyst, characterized by a high percentage of glycerol trimers <strong>and</strong>tetramers. The exceptional activity of Cs-X reported in <strong>the</strong> literature is obviously <strong>as</strong>sociated with<strong>the</strong> observed structural instability <strong>and</strong> <strong>the</strong> rele<strong>as</strong>e of Cs. This conclusion w<strong>as</strong> corroborated byresults obtained <strong>for</strong> <strong>the</strong> more stable Cs-Y, where practically no trimers or tetramers were foundafter comparable reaction time. A shift of diglycerol distribution in favor of <strong>the</strong> αβ-isomer w<strong>as</strong>observed over Cs-Y.DFT calculations showed that <strong>the</strong> energetically most favored anionic glycerol con<strong>for</strong>mation resultedafter charge location at <strong>the</strong> middle oxygen. A nucleophilic attack to a CH 2 OH group of a secondglycerol leads to αβ-diglycerol. On <strong>the</strong> o<strong>the</strong>r h<strong>and</strong>, <strong>the</strong> calculations on dimers <strong>and</strong> <strong>the</strong>ir anionsshows that <strong>the</strong>rmodynamic stability of dimer con<strong>for</strong>mation are αα’ ≈ αβ > ββ’, respectively.The ongoing in-depth study on <strong>the</strong> peculiarity of cesium <strong>for</strong> catalyzing <strong>the</strong> glycerol e<strong>the</strong>rificationunder solvent-free conditions h<strong>as</strong> shown that <strong>the</strong> outst<strong>and</strong>ing activity of Cs-X is due obviously to<strong>the</strong> prevailing homogenous Cs catalyzed reaction, after collapsing of <strong>the</strong> zeolite structure underreaction conditions.References[1] J.-M. Clacens, Y. Pouilloux, J. Barrault, C. Linares, M. Goldw<strong>as</strong>ser, Stud. Surf. Sci. Catal. 118(1998) 895.[2] J. Barrault, J.-M. Clacens, Y. Pouilloux, Topics Catal. 27 (2004) 137.[3] J.-M. Clacens, Y. Pouilloux, J. Barrault, Appl. Catal. A: General 227 (2002) 181.[4] C.C. Sweeley, R. Bentley, M. Makita, W.W. Wells, J. Amer. Chem. Soc. 85 (1963) 2497.[5] Y.K. Krisn<strong>and</strong>i, M. Checinski, R. Eckelt, A. Martin, M. Richter, publication in preparation.30
P4Syn<strong>the</strong>sis <strong>and</strong> Characterization of Biob<strong>as</strong>ed Allyl AcrylatesGökhan Çaylı, Selim Küsefoğlu *Boğaziçi University Istanbul,TurkeyDepartment of Chemistry* kusef@boun.edu.trAllyl acrylates are versatile compounds <strong>and</strong> <strong>the</strong>y are used in wide variety applicationsfrom photo resist resins to dental products. Mostly, Allyl acrylates are syn<strong>the</strong>sized byesterification reaction between allyl alcohols <strong>and</strong> acyl chlorides of acrylates. These acylchlorides are very toxic <strong>and</strong> allyl alcohol is not found in nature. In this study, an e<strong>as</strong>y <strong>and</strong>efficient method <strong>for</strong> syn<strong>the</strong>sizing of allyl acrylates which are derived from methyl oleate ispresented. There are two steps in <strong>the</strong> procedure. At <strong>the</strong> first step allylic bromides of methyloleate is syn<strong>the</strong>sized <strong>and</strong> at <strong>the</strong> second step, replacing of <strong>the</strong> bromine on <strong>the</strong> allylicpositions of methyl oleate with Na + or K + salts of acrylic or methacrylic acids occurs. Theyield of <strong>the</strong> reaction is around 70 % <strong>for</strong> methacrylic acid <strong>and</strong> 85% <strong>for</strong> acrylic acid.Purification of <strong>the</strong> products is done with column chromatography. The homo <strong>and</strong>copolymers of <strong>the</strong>se monomers are prepared by free radical polymerization techniques.31
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