Polyglycerol (PGL) is a polyhydroxyl compound obtained by selfcondensation of glycerol in the presence of alkaline catalysts. It is a very attractive polyol as a starter for the synthesis of polyether polyols for rigid polyurethane foams. It is liquid, easy to handle and has a very high average functionality of 4—20 (or more) hydroxyl groups/mol. By propoxylation of PGL or PGL—sucrose mixtures, we obtained new polyether polyols with very high functionalities, which are very difficult or impossible to obtain by other methods. A new technology for PGL-based polyether polyols preparation was investigated. In the first step the self-polycondensation of glycerol to PGL in the presence of potassium hydroxide or potassium methoxide as a catalyst was carried out. In the second step, the crude alkaline PGL was alkoxylated with PO without removing the catalyst, followed by purification of the resulting polyether polyols. Rigid polyurethane foams prepared from the synthesized PGL-based polyether polyols and crude MDI displayed good physical and mechanical properties, excellent dimensional stability, and low friability.
Ionescu, M. ( 2005). Chemistry and Technology of Polyols for Polyurethanes, Shrewsburty, Shropshire, UK. Rapra Technology Ltd. Shawbury.
2.
Naweenkumar, T., Sastry, Y.S.R. and Lakshiminarayana , G.Analysis of Polyglycerols by High-performance Liquid Chromatography, J. Chromatogr. , 1984: 298: 360-365.
3.
Ruppert, A.M. , Meeldijk, J.D., Kuipers, B.W.M., Ern , B.H. and Weckhuysen , B.M.Glycerol Etherification over Highly Active CaO-based Materials: New Mechanistic Aspects and Related Colloidal Particle Formation, Chem. Eur. J., 2008: 14: 2016-2024.
4.
De Meulenaer, V.B. and Huyghebaert , A.Development of Chromatographic Method for the Determination of Degree of Polymerisation of Polyglycerols and Polyglycerol Fatty Acid Esters, Chromatographia, 2000: 51: 44-52.
5.
Jakobson, G.Diglycerin und hohere Oligomere des Glycerins als Synthesebausteine, Fette, Seifen Anstrichmittel, 1986: 88: 101-106.
6.
Dolhaine, H. , Preuss, W. and Wollmann, K.Strukturen im Polyglycerin, Fette, Seifen Anstrichmittel, 1984: 86: 339-343.
7.
Francoois, J. , Pouilloux, Y. and Barrault, J.Rational Design of Solid Catalysts for the Selective Use of Glycerol as a Natural Organic Building Block, ChemSusChem., 2008: 1: 586-613.
8.
Cassel, S., Debaig, C., Benvegnu, T., et al. Original Synthesis of Linear, Branched and Cyclic Oligoglycerol Standards, Eur. J. Org. Chem., 2001: 2001: 875-896.
9.
Zerrer, R. and Scherl, F.X. ( 2004) Method for the Production of Polyglycerol Ethers by Directly Reacting Polyglycerols with Alcohols, WO2004074346.
10.
Lemke, D.W. ( 2002), Processes for Preparing Linear Polyglycerols and Polyglycerol Esters, US Patent 20020058781.
11.
Leinweber, D., Scherl, X.F., Wasmund E. and Grundner H. ( 2004). Alkoxylated Polyglycerols and their Use as Demulsifiers, US Patent 20040072916.
12.
Jakobson, G. and Siemanowski, W. ( 1991). Process for the Preparation of Polyglycerols, US Patent5,041,688.
13.
Eshuis, J.W. , Laan, J.A.M. and Roberts , G. ( 1998). Polyglycerol Production, US Patent5,721,305.
14.
Sunder, A. and Mulhaupt, R. ( 2003). Method for Producing Highly-branched Glycidol-based Polyols, US Patent Appl. 20030120022.
15.
Lemke, D.W. ( 2002). Processes for Preparing Linear Polyglycerols and Polyglycerol Esters, WO 0236534.
16.
Seiden, P.M. and James, B. (1976). Process for Preparing Polyglycerol, US Patent3,968,169.
17.
Stuhler, H. (1985). Process for the Preparation of Polyglycerols, US Patent4,551,561.
18.
Clacens, J.M. , Pouilloux, Y. and Barrault, J.Selective Etherification of Glycerol to Polyglycerols over Impregnated Basic MCM-41 type Mesoporous Catalysts, Appl. Catal., A, 2002: 227: 181.
19.
Barrault, J. , Pouilloux, Y., Clacens , J.M., Vanhove, C. and Bancquart, S.Catalysis and Fine Chemistry, Catal. Today, 2002: 75: 177-181.
20.
Barrault, J. , Clacens, J.M. and Pouilloux , Y.Selective Oligomerization of Glycerol over Mesoporous Catalysts, Top. Catal., 2004: 27: 137-142.
21.
Clacens, J.M. , Pouilloux, Y., Barrault , J., Linares, C. and Goldwasser, M.Designed of Modified Mesoporous Silica for Selective Preparation of Diglycerol Esters in One Step, Stud. Surf. Sci. Catal., 1998 : 118: 895-902.
22.
Behrens, H. and Mieth, G.Synthese, Charakterisierung und Applikation von Polyglycerolen und Polyglycerolfettsaureestern, Die Nahrung , 1984: 28: 815-835.
23.
Heteren, J. and Poot, C.Fats Containing Polyglycerol Esters, EP 0070080, Unilever N.V.
24.
Kleemann, A. , Wagner, R., Okyam, G. et al. (1981). Glycidol, Heidelberg , Huthig-Verlag.
25.
Knischka, R. , Lutz, P.J.Sunder , A., Mülhaupt, R., and Frey, H.Functional Poly(ethylene oxide) Multiarm Star Polymers: Core-first Synthesis Using Hyperbranched Polyglycerol Initiators , Macromolecules , 2000: 33: 315-320.
26.
Sunder, A., Mülhaupt, R. and Frey, H.Hyperbranched Polyether-Polyols Based on Polyglycerol: Polarity Design by Block Copolymerization with Propylene Oxide, Macromolecules , 2000: 33: 309-314.
27.
Sunder, A., Bauer, T., Mülhaupt, R. and Frey, H.Synthesis and Thermal Behavior of Esterified Aliphatic Hyperbranched Polyether Polyols, Macromolecules, 2000: 33: 1330-1337.
28.
Wittcoff, H. , Roach, J.R., Miller, S.E.Polyglycerols. I. The Identification of Polyglycerol Mixtures by the Procedures of Allylation and Acetonation: Isolation of Pure Diglycerol, J. Am. Chem. Soc., 1947 : 69: 2655-2657.
29.
Kainthan, R.K. , Muliawan, E.B., Hatzikiriakos , S.G. and Brooks, D.E.Synthesis, Characterization, and Viscoelastic Properties of High Molecular Weight Hyperbranched Polyglycerols , Macromolecules, 2006: 39: 7708-7717.
30.
Roach, J.R. and Wittcoff, H.Polyglycerols. III, Synthesis of Triglycerol , J. Am. Chem. Soc., 1949: 71: 3944-3946.
31.
Wittcoff, H. , Roach, J.R. and Miller, S.E.Polyglycerols. II. Syntheses of Diglycerol , J. Am. Chem. Soc. , 1949: 71: 2666-2668.
