2,2,4,4-Tetramethyl-1,3-cyclobutanediol

changed changed 477209581 CBDO.png cis- (left) and trans-2,2,4,4-Tetramethyl-1,3-cyclobutanediol (right) 2,2,4,4-tetramethyl-1,3-cyclobutanediol (E)-CBDO-3D-balls.png 120 Trans CBDO molecule (Z)-CBDO-3D-balls.png 120 Cis CBDO molecule 2,2,4,4-Tetramethylcyclobutane-1,3-diol 1,1,3,3-Tetramethyl-2,4-cyclobutanediol correct chemspider 68858 FQXGHZNSUOHCLO-UHFFFAOYAA changed ?? 3010-96-6 changed FDA 9T56625HW3 76382 1/C8H16O2/c1-7(2)5(9)8(3,4)6(7)10/h5-6,9-10H,1-4H3 OC1C(C)(C)C(O)C1(C)C correct chemspider 1S/C8H16O2/c1-7(2)5(9)8(3,4)6(7)10/h5-6,9-10H,1-4H3 correct chemspider FQXGHZNSUOHCLO-UHFFFAOYSA-N 8 16 2 Crystalline white solid (powder) 126 to 134 210 to 215 51 2,2,4,4-Tetramethyl-1,3-cyclobutanediol (CBDO) is an aliphatic diol. This diol is produced as a mixture of cis- and trans-isomers, depending on the relative stereochemistry of the hydroxyl groups. It is used as a monomer for the synthesis of polymeric materials, usually as an alternative to bisphenol A (BPA). CBDO is used in the production of tritan copolyester which is used as a BPA-free replacement for polycarbonate. Replacement for BPA The controversies associated with BPA in large quantities are ultimately related to its endocrine disrupting abilities.vom Saal Frederick S. Hughes Claude August 2005 An Extensive New Literature Concerning Low-Dose Effects of Bisphenol A Shows the Need for a New Risk Assessment Environmental Health Perspectives en 113 8 926–933 10.1289/ehp.7713 0091-6765 1280330 16079060 2005EnvHP.113..926V Like BPA, CBDO is a diol with a structure suitable for making polyesters. CBDO’s C4 ring is sufficiently rigid to prevent the two OH groups from forming cyclic structures. Unlike BPA, there is no current evidence of carcinogenic or toxic effects from CBDO-based consumer products. There are, however, few studies on the toxicology of CBDO for both long term and short term effects. CBDO has potential advantages relative to BPA as a building block for production of polyesters. CBDO is very stable thermally and mechanically. Polyesters prepared from CBDO are rigid materials, but the combination of CBDO with flexible diols results in materials with high impact resistance, low color, thermal stability, good photooxidative stability and transparency.Hoppens Nathan C. Hudnall Todd W. Foster Adam Booth Chad J. 2004-07-15 Aliphatic–aromatic copolyesters derived from 2,2,4,4-tetramethyl-1,3-cyclobutanediol https://onlinelibrary.wiley.com/doi/10.1002/pola.20197 Journal of Polymer Science Part A: Polymer Chemistry en 42 14 3473–3478 10.1002/pola.20197 2004JPoSA..42.3473H 0887-624X subscription As an added bonus, CBDO-derived polymers have high ductility.Kelsey Donald R. Scardino Betty M. Grebowicz Janusz S. Chuah Hoe H. 2000-08-01 High Impact, Amorphous Terephthalate Copolyesters of Rigid 2,2,4,4-Tetramethyl-1,3-cyclobutanediol with Flexible Diols https://pubs.acs.org/doi/10.1021/ma000223%2B Macromolecules en 33 16 5810–5818 10.1021/ma000223+ 2000MaMol..33.5810K 0024-9297 subscription The thermal and mechanical properties of CBDO-derived polyesters are often superior to conventional polyesters. Preparation Synthesis of CBDO involves pyrolysis of isobutyric anhydride followed by hydrogenation of the resulting 2,2,4,4-tetramethylcyclobutanedione.Wedeking E. Weisswange W. March 1906 Ueber die Synthese eines Diketons der Cyclobutanreihe https://chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/cber.19060390287 Berichte der Deutschen Chemischen Gesellschaft en 39 2 1631–1646 10.1002/cber.19060390287 0365-9496 This synthesis resembles the method used to produce CBDO today. The first step involves conversion of the isobutyric acid or its anhydride into the ketene. This ketene then dimerizes to form a four-membered ring with two ketone groups. The product ring is hydrogenated to give a diol. The last step commonly involves catalytic hydrogenation with ruthenium, nickel, or rhodium catalysts. Hydrogenation of the diketone ring results in both cis and trans isomers.W. Theilheimer "1,3-Cyclobutanediols from 1,3-cyclobutandiones" Synthetic Methods of Organic Chemistry, 1962, Volume 16, pp. 29. A simplified scheme for the production of CBDO is presented below. 500px Structure and properties The C4 ring of the cis isomer of CBDO is non-planar. For simple non-planar cyclobutanes, dihedral angles range from 19 to 31°. CBDO’s cis isomer crystallizes as two conformers with an average dihedral angle of 17.5° in the solid state.Shirrell C. D. Williams D. E. 1976-06-01 The crystal and molecular structure of cis -2,2,4,4-tetramethyl-1,3-cyclobutanediol https://scripts.iucr.org/cgi-bin/paper?S0567740876006559 Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry 32 6 1867–1870 10.1107/S0567740876006559 1976AcCrB..32.1867S 0567-7408 subscription However, the trans isomer has a dihedral angle of 0°.Margulis T. N. 1969 Planar cyclobutanes: structure of 2,2,4,4-tetramethyl-cyclobutane-trans-1,3-diol http://xlink.rsc.org/?DOI=c29690000215 Journal of the Chemical Society D: Chemical Communications en 5 215–216 10.1039/c29690000215 0577-6171 subscription Polyesterification The current economic method for the production of polyesters is direct esterification of dicarboxylic acids with diols. This condensation polymerization adds monomeric units to a chain. Individual chains react with one another through carboxyl and hydroxyl terminal groups. Finally, transesterification occurs within the chain.Köpnick Horst Schmidt Manfred Brügging Wilhelm Rüter Jörn Kaminsky Walter Polyesters 10.1002/14356007.a21_227 Although CBDO is most often used in polyesters, mixed copolycarbonates of CBDO and a series of bisphenols have also been synthesized. The differing reactivities of the cis and trans isomers have not been studied in depth. References Category:Monomers Category:Diols Category:Cyclobutanes