Valorisation of plastic waste via metal-catalysed depolymerisation

• Francesca Liguori,
• Carmen Moreno-Marrodán and
• Pierluigi Barbaro

Beilstein J. Org. Chem. 2021, 17, 589–621, doi:10.3762/bjoc.17.53

• and the carbonyl group of polyester [200]. Indeed, several studies showed Zn-based catalysts to provide the best performances. A summary of recent findings and reaction conditions is reported in Table 2. In an earlier study, a 85.6% BHET yield was obtained at 196 °C, using an EG/PET ratio of 5:1 (w/w

Synthesis of esters of diaminotruxillic bis-amino acids by Pd-mediated photocycloaddition of analogs of the Kaede protein chromophore

• Esteban P. Urriolabeitia,
• Pablo Sánchez,
• Alexandra Pop,
• Cristian Silvestru,
• Eduardo Laga,
• Ana I. Jiménez and
• Carlos Cativiela

Beilstein J. Org. Chem. 2020, 16, 1111–1123, doi:10.3762/bjoc.16.98

• chromatography (TLC) was performed on Macherey-Nagel Polygram® SIL G/UV254 silica gel on polyester sheets, with manganese-activated zinc silicate with green fluorescence for short-wave UV (254 nm) and special inorganic fluorescent pigment with blue fluorescence for long-wave UV (366 nm) as indicators. Fluka

Photophysics and photochemistry of NIR absorbers derived from cyanines: key to new technologies based on chemistry 4.0

• Bernd Strehmel,
• Christian Schmitz,
• Ceren Kütahya,
• Yulian Pang,
• Anke Drewitz and
• Heinz Mustroph

Beilstein J. Org. Chem. 2020, 16, 415–444, doi:10.3762/bjoc.16.40

• coating, where they properly helped to melt and cure the applied powder monomers nearly just in one step [16]. Typical monomers used in CtP, liquid coatings and powder coatings derive from urethane (meth)acrylates, epoxy (meth)acrylates, polyester(meth)acrylates or polyether (meth)acrylates. Literature

Olefin metathesis in multiblock copolymer synthesis

• Maria L. Gringolts,
• Yulia I. Denisova,
• Eugene Sh. Finkelshtein and
• Yaroslav V. Kudryavtsev

Beilstein J. Org. Chem. 2019, 15, 218–235, doi:10.3762/bjoc.15.21

• 1,4-polybutadiene or natural polyisoprene and olefin-containing polyester or polyurethane prepared via step-growth polymerization (Figure 4B and C) [83][84][85]. The multiblock copolymers from polybutadiene and olefin-containing polyurethane demonstrated improved mechanical properties [85]. Head-to

• multiblock copolymers formed with the cross metathesis of PBD and olefin-containing polyester (Scheme 10A) [84]. It was shown that shortening the block length in both the olefinically unsaturated and hydrogenated copolymers resulted in a decrease, and, finally, in the extinction of Tm. At the same time

Copolymerization of epoxides with cyclic anhydrides catalyzed by dinuclear cobalt complexes

• Yo Hiranoi and
• Koji Nakano

Beilstein J. Org. Chem. 2018, 14, 2779–2788, doi:10.3762/bjoc.14.255

• . However, there are some burdensome requisites, such as a precise stoichiometric balance between the carboxy and hydroxy groups and an efficient removal of small molecule byproducts, for the high conversion. Another conventional method for polyester synthesis is the chain-growth ring-opening polymerization

• alternating copolymerization of epoxides with cyclic anhydrides (CAs) is a promising alternative for polyester synthesis [11][12]. A broad range of epoxides and CAs are readily available and can be copolymerized through this method. Therefore, the polymer architectures and properties can be easily controlled

• developed based on well-defined metal complexes such as metalloporphyrins and metal–salen complexes [15][16][17][18][19][20][21]. In parallel to the development of catalysts, new polyester materials also were prepared by employing unprecedented monomers or by the combination with other polymerization

Theoretical simulation of the infrared signature of mechanically stressed polymer solids

• Matthew S. Sammon,
• Milan Ončák and
• Martin K. Beyer

Beilstein J. Org. Chem. 2017, 13, 1710–1716, doi:10.3762/bjoc.13.165

• uneven distribution of the external stress on individual polymer strands is accounted for by a convolution of simulated spectra with a realistic force distribution. N-Propylpropanamide and propyl propanoate are chosen as model molecules for polyamide and polyester, respectively. The effect of a specific

• spectroscopy; mechanical stress; polyamide; polyester; Introduction Mechanical stress on polymer solids leads to conformational changes, bond elongation and widening of bond angles on the molecular level [1][2][3][4]. If the local force on an individual polymer strand reaches values in the range of nN

• molecules for polyamide and polyester, respectively. To facilitate a comparison with future experimental studies, we convolute simulated infrared spectra with the exponential force distribution recently derived by Adhikari and Makarov for elastomeric polymer networks [81]. Results and Discussion Amide We

Mechanochemistry-assisted synthesis of hierarchical porous carbons applied as supercapacitors

• Desirée Leistenschneider,
• Nicolas Jäckel,
• Felix Hippauf,
• Volker Presser and
• Lars Borchardt

Beilstein J. Org. Chem. 2017, 13, 1332–1341, doi:10.3762/bjoc.13.130

• polymerization of the educts induced by mechanochemical forces by IR spectroscopy (Figure 2). Two bands at 1703 cm−1 and 1136 cm−1 appear, indicating the formation of the polyester (EG-CA). Likewise, the characteristic bands of the educts (CA: 1210 cm−1; EG: 1418 cm−1) become less pronounced and much broader as

Detection of therapeutic radiation in three-dimensions

• John A. Adamovics

Beilstein J. Org. Chem. 2017, 13, 1325–1331, doi:10.3762/bjoc.13.129

• equivalent [43][44][45]. Polyurethane Acrylic, epoxy, polycarbonate, polyester, polystyrene, polyurethane, polyvinyl chloride and silicone were the common transparent plastics that were evaluated as potential 3D dosimeter matrices [17]. Polyvinyl chlorides and silicones were not further considered since

• typically a mixture of dicyclohexylmethane-4,4'-diisocyanate (HMDI, Figure 2) and it’s polyether prepolymer (CAS 531-70-03-9). While part B is a polyether or polyester polyol mixture which is proprietary [46]. Other aliphatic diisocyanate also used are 1,6-hexamethylene diisocyanate (HDI) and isophorone

Dynamics and interactions of ibuprofen in cyclodextrin nanosponges by solid-state NMR spectroscopy

• Monica Ferro,
• Franca Castiglione,
• Nadia Pastori,
• Carlo Punta,
• Lucio Melone,
• Walter Panzeri,
• Barbara Rossi,
• Francesco Trotta and
• Andrea Mele

Beilstein J. Org. Chem. 2017, 13, 182–194, doi:10.3762/bjoc.13.21

• chiral selectors for the enantioseparation of racemic ibuprofen [32]. In our case, the primary OH groups of CD units react with EDTA dianhydride to form a cross-linked polyester. As a matter of fact, this type of polycondensation makes the CD cavity less available compared to the former case. The overall

Rearrangements of organic peroxides and related processes

• Ivan A. Yaremenko,
• Vera A. Vil’,
• Dmitry V. Demchuk and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2016, 12, 1647–1748, doi:10.3762/bjoc.12.162

• used in anticorrosive composites, polyester and polyamide threads, and lubricants, for the synthesis of tridecanedioic acid, and as a component of perfume formulations. Scheme 35 presents the synthesis of hydroxy-10H-acridin-9-one 117 starting from tetramethoxyanthracene 114 through the formation of

Dicarboxylic esters: Useful tools for the biocatalyzed synthesis of hybrid compounds and polymers

• Ivan Bassanini,
• Karl Hult and
• Sergio Riva

Beilstein J. Org. Chem. 2015, 11, 1583–1595, doi:10.3762/bjoc.11.174

• the synthesis of “sweet silicones” by Novozyme 435-catalyzed formation of ester bonds between organosilicon carboxylic diacids and the primary OH’s of 1-O-alkyl glucopyranosides [47]. 2. Enzymatic synthesis of polyesters The interest in the biocatalyzed synthesis of polyester started at the very

• activated 2,2,2-trichloroethyl diester of (±)-3,4-epoxyadipic acid. The stereoselectivity of porcine pancreatic lipase discriminated between the two enantiomers and afforded the chiral (−)-polyester with molecular weight of 7900 Dalton (Figure 9). Yang et al. compared the polymerization of glycerol and a

• . Symmetrical long-chain (C18, C20 and C26) unsaturated or epoxidized dicarboxylic acids were polycondensated with 1,3-propanediol or 1,4-butanediol using CAL-B [60]. At high temperature (70 °C) a number of polyester combinations could be synthesized. Propandiol afforded polymers with rather moderate molecular

The chemical behavior of terminally tert-butylated polyolefins

• Dagmar Klein,
• Henning Hopf,
• Peter G. Jones,
• Ina Dix and
• Ralf Hänel

Beilstein J. Org. Chem. 2015, 11, 1246–1258, doi:10.3762/bjoc.11.139

• Dagmar Klein Henning Hopf Peter G. Jones Ina Dix Ralf Hanel Institut für Organische Chemie, Technische Universität Braunschweig, Hagenring 30, D-38106 Braunschweig, Germany, Fax: (+49)531-391-5388 Current address: Mitsubishi Polyester Film GmbH, Kasteler Str. 45, 65203 Wiesbaden, Germany Institut

Modification of physical properties of poly(L-lactic acid) by addition of methyl-β-cyclodextrin

• Toshiyuki Suzuki,
• Ayaka Ei,
• Yoshihisa Takada,
• Hiroki Uehara,
• Takeshi Yamanobe and
• Keiko Takahashi

Beilstein J. Org. Chem. 2014, 10, 2997–3006, doi:10.3762/bjoc.10.318

• ) of approximately 170 °C must be increased because of the low thermal resistance. The melting point of the stereo complex (Sc) of PLLA and poly(D-lactic acid) (PDLA) is higher than 220 °C [1][2][3][4][5], which is comparable to that of aromatic polyester. Many studies have been conducted for improving

Electrocarboxylation: towards sustainable and efficient synthesis of valuable carboxylic acids

• Roman Matthessen,
• Jan Fransaer,
• Koen Binnemans and
• Dirk E. De Vos

Beilstein J. Org. Chem. 2014, 10, 2484–2500, doi:10.3762/bjoc.10.260

• –Schmidt reaction at high temperatures and CO2 pressures [13][14][15]. Sodium phenolate is selectively converted to salicylic acid, a precursor of Aspirin, while potassium phenolate exclusively yields p-hydroxybenzoic acid, used in polyester synthesis (Scheme 1) [16][17][18][19][20]. In order to generate

Copolymerization and terpolymerization of carbon dioxide/propylene oxide/phthalic anhydride using a (salen)Co(III) complex tethering four quaternary ammonium salts

• Jong Yeob Jeon,
• Seong Chan Eo,
• Jobi Kodiyan Varghese and
• Bun Yeoul Lee

Beilstein J. Org. Chem. 2014, 10, 1787–1795, doi:10.3762/bjoc.10.187

• attained at the PA feeding of 1.0 g. Related stereogradient CO2/PO copolymers have been reported, in which one end of the polymer chain is enriched with the R-isomer of PO, while the other is enriched with the S-isomer [33][34]. A related copolymer composed of aliphatic polycarbonate and aromatic polyester

Streptopyridines, volatile pyridine alkaloids produced by Streptomyces sp. FORM5

• Ulrike Groenhagen,
• Michael Maczka,
• Jeroen S. Dickschat and
• Stefan Schulz

Beilstein J. Org. Chem. 2014, 10, 1421–1432, doi:10.3762/bjoc.10.146

• flash chromatography using Merck silica gel 60 (70–200 mesh). Thin-layer chromatography was performed with 0.2 mm pre-coated polyester sheets (Polygram SIL (G/UV254), Macherey-Nagel). NMR spectra were obtained on either a Bruker DRX-400 (400 MHz) or an AV III-400 (400 MHz) spectrometer and were

N-Alkylated dinitrones from isosorbide as cross-linkers for unsaturated bio-based polyesters

• Oliver Goerz and
• Helmut Ritter

Beilstein J. Org. Chem. 2014, 10, 902–909, doi:10.3762/bjoc.10.88

• unsaturated polyester was cross-linked by a 1,3-dipolar cycloaddition with the received dinitrones 10a/b. The 1,3-dipolar cycloaddition led to a strong change of the mechanical properties which were investigated by rheological measurements. Nitrones derived from methyl acrylate (3a) and methyl crotonate (3b

• -dipolar cycloaddition with unsaturated bio-based polyester poly(isosorbide itaconate -co- succinate). Results and Discussion N-Alkylated dinitrones derived from acrylates and crotonates were prepared and evaluated in respect to their 1,3-cycloaddition with itaconic acid containing polyester resins. To

• to dissolve byproducts and catalyst. The pure compounds were obtained by additionally washing with diethyl ether. In order to proof the ability of dinitrones to form three-dimensional networks with itaconate moieties containing polyesters, the bio-based unsaturated polyester 13 was synthesized from

Damage of polyesters by the atmospheric free radical oxidant NO₃^•: a product study involving model systems

• Catrin Goeschen and
• Uta Wille

Beilstein J. Org. Chem. 2013, 9, 1907–1916, doi:10.3762/bjoc.9.225

• well as products of these reactions are potentially capable of promoting further degradation processes in polyesters under environmental conditions. Keywords: environmental oxidants; free radicals; nitrate radicals; polyester degradation; product studies; reaction mechanisms; Introduction Polymers

• •, O2 and O3. This work not only reveals new insight into the degradation mechanism in polyesters upon exposure to important environmental oxidants, but it also enables identification of vulnerable sites (‘hot spots’) in the polymer, which could open up new pathways to polyester degradation under

• polyester-model substrate and four equivalents of CAN were dissolved in acetonitrile and the solutions degassed by sonicating under a continuous argon stream, followed by irradiation and aqueous work-up. Control experiments performed under exclusion of light showed no reaction, which ensured that the

Restructuring polymers via nanoconfinement and subsequent release

• Alan E. Tonelli

Beilstein J. Org. Chem. 2012, 8, 1318–1332, doi:10.3762/bjoc.8.151

• recently observed that PVAc coalesced from its IC formed with host urea (U) behaves quite similarly to PVAc coalesced from its γ-CD IC [72]. Coalesced semicrystalline polymers Poly(ε-caprolactone) (PCL) is a biodegradable/bioabsorbable aliphatic polyester that is often used in biomedical applications, such

Imidazole as a parent π-conjugated backbone in charge-transfer chromophores

• Jiří Kulhánek and
• Filip Bureš

Beilstein J. Org. Chem. 2012, 8, 25–49, doi:10.3762/bjoc.8.4

• . These chromophores, with free terminal OH-functions, were further used as monomers for copolymerization with polyester, polyuretane, and polymethacrylate (see below). Structurally very similar chromophore 87 (R = H; R1 = CH2CH2OH; R2 = Et) was used for incorporation into the sol–gel hybrid films based

• polyuretane and polyester by solution copolymerization with tolylene-2,4-diisocyanate (TDI), (2-methoxy)terephthaloyl dichloride [(M)TPC], and isophthaloyl dichloride (IPC) to afford nonlinear optical polymers 135–140. Polymers 141–143 were synthesized by AIBN-promoted polymerization of the methacrylate

• . However, the achieved nonlinearities are still lower than those measured for previous polymeric systems, e.g., 119 and 126–128. Chromophores 67 and 68 attached to polyamide and polyester backbones by copolymerization with m-phenylenediamide (MPD) and isophthaloyl dichloride (IPC) as well as bis

The cross-metathesis of methyl oleate with cis-2-butene-1,4-diyl diacetate and the influence of protecting groups

• Arno Behr and
• Jessica Pérez Gomes

Beilstein J. Org. Chem. 2011, 7, 1–8, doi:10.3762/bjoc.7.1

• -metathesis selectivity under mild reaction conditions. These two cross-metathesis products can be potentially used as functional monomers for diverse sustainable polymers. Keywords: cross-metathesis; methyl oleate; monomer; polyester; renewable resources; Introduction In the last decade, olefin metathesis

Poly(glycolide) multi-arm star polymers: Improved solubility via limited arm length

• Florian K. Wolf,
• Anna M. Fischer and
• Holger Frey

Beilstein J. Org. Chem. 2010, 6, No. 67, doi:10.3762/bjoc.6.67

• compared to the homopolymer PGA should lead to simplified processing conditions. The findings contribute to broadening the range of biomedical applications of PGA. Keywords: block copolymer; hyperbranched; PGA; polyester; polyglycerol; poly(glycolide); star polymer; Introduction Linear aliphatic

Synthesis of bis(3-{[2-(allyloxy)ethoxy]methyl}-2,4,6-trimethylbenzoyl)(phenyl)phosphine oxide – a tailor-made photoinitiator for dental adhesives

• Norbert Moszner,
• Iris Lamparth,
• Jörg Angermann,
• Urs Karl Fischer,
• Frank Zeuner,
• Thorsten Bock,
• Robert Liska and
• Volker Rheinberger

Beilstein J. Org. Chem. 2010, 6, No. 26, doi:10.3762/bjoc.6.26

• Vivadent AG) and an irradiation time of 180 s at 37 °C. For the measurement of the shear bond strength of the corresponding dentin adhesives, freshly extracted bovine lower incisors were embedded in unsaturated polyester resin (Castolite, Buehler, USA) in cylindrical molds. Flat dentinal surfaces were