01966nas a2200193   4500008004100000022001400041245015200055210006900207260009900276300001400375490000700389520115400396653001801550653003301568653001801601100001301619700001401632856012601646       2005                        eng d  a0032-386100aMorphological consequences of interchange reactions during solid state copolymerization in poly(ethylene terephthalate) and polycarbonate oligomers0 aMorphological consequences of interchange reactions during solid  aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLANDbELSEVIER SCI LTDcAUG  a7443-74490 v463 a<p>Poly(ethylene terephthalate) (PET) (IV:0.15dL/g) oligomer was obtained by depolymerisation of high molecular weight PET. Polycarbonate (PC) oligomer (IV: 0. 15 dL/g) was synthesized by standard melt polymerization procedure using bisphenol A and diphenyl carbonate in the presence of a basic catalyst. Blends of varying compositions were prepared by melt blending the chemically distinct PET and PC oligomers. The copolymer, poly(ethylene terephthalate-co-bisphenol A carbonate) was synthesized by simultaneous solid state polymerization and ester-carbonate interchange reaction between the oligomers of PET and PC. The reaction was carried out under reduced pressure at temperatures below the melting temperature of the blend samples. DSC and WAXS techniques characterized the structure and morphology of the blends, while (NMR)-N-1 spectroscopy was used to monitor the progress of interchange reactions between the oligomers. The studies have indicated the amorphisation of the PET and PC crystalline phases in solid state with the progress of solid-state polymerization and interchange reaction. (c) 2005 Elsevier Ltd. All rights reserved.</p>10aamorphization10apoly(ethylene terephthalate)10aPolycarbonate1 aGowd, EB1 aRamesh, C  uhttps://library.ncl.res.in/content/morphological-consequences-interchange-reactions-during-solid-state-copolymerization-002099nas a2200241   4500008004100000022001400041245016700055210006900222260007300291300001200364490000800376520114000384653003001524653003101554653002101585653003401606653001801640653001701658100001801675700001601693700001701709856013101726       2005                        eng d  a0926-860X00aZeolite-based organic-inorganic hybrid catalysts for phosgene-free and solvent-free synthesis of cyclic carbonates and carbamates at mild conditions utilizing CO20 aZeolitebased organicinorganic hybrid catalysts for phosgenefree   aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcAUG  a128-1340 v2893 a<p>As-synthesized zeolite-beta exhibits high catalytic activity for the synthesis of cyclic carbonates and alkyl and aryl carbarnates by a phosgene-free route, utilizing the greenhouse effect gas CO2. The reaction occurs with high yields of the desired products at mild conditions and without using any solvent or cocatalyst. Cyclic carbonates are synthesized by cycloaddition reaction Of CO2 with oxiranes (epichlorohydrin, propene oxide, styrene oxide and n-butene oxide) at 393 K and 6.9 bar. Alkyl and aryl carbarnates are synthesized by the reaction of the corresponding amines, CO2 and n-butyl bromide at 353 K and 3.4 bar. The as-synthesized zeolite-beta containing the encapsulated quaternary ammonium ions is not only reusable in several recycling experiments, but also shows superior activity to that of the corresponding homogeneous, quaternary ammonium halide salt generally used in the commercial synthetic practice. The microporous silica (inorganic) acting in concert with the encapsulated organic component constitutes an efficient, recyclable catalyst for this reaction. (c) 2005 Elsevier B.V. All rights reserved.</p>10aalkyl and aryl carbamates10acarbon dioxide utilization10acyclic carbonate10aphosgene-free synthetic route10aPolycarbonate10azeolite-beta1 aSrivastava, R1 aSrinivas, D1 aRatnasamy, P  uhttps://library.ncl.res.in/content/zeolite-based-organic-inorganic-hybrid-catalysts-phosgene-free-and-solvent-free-synthesis-001943nas a2200229   4500008004100000022001400041245010800055210006900163260007600232300001400308490000800322520112100330653001401451653001401465653002301479653001901502653001801521653001401539100002001553700001801573856012201591       2011                        eng d  a0020-760800aAb initio calculations of the geometry and polarizabilities of bisphenyls having aliphatic substituents0 aAb initio calculations of the geometry and polarizabilities of b  aCOMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USAbWILEY-BLACKWELLcAPR  a1092-11000 v1113 a<p>Ab initio geometry optimization and polarizability calculations of a series of bisphenyls, which are the model compounds of chemically different polycarbonates using HF/6-31G and 6-31G** basis sets are presented. Calculated absolute value of the conformationally averaged optical anisotropy (<gamma(2)>) of diphenyl propane, a model analog of bisphenol A polycarbonate, is higher than the corresponding experimental value in the dilute solution phase. The calculations have reproduced the relative trend in the optical anisotropy for the different bisphenyl model compounds in a manner similar to those using semiclassical approach, by incorporation of the condensed phase polarizabilities and quantum chemically calculated geometry structure into the valence optical scheme. Individual contributions to the gas phase polarizability and optical anisotropy of the model compounds for various dihedral conformers, because of the presence of different aliphatic chemical groups, are correctly predicted by the calculations here. (C) 2010 Wiley Periodicals, Inc. Int J Quantum Chem 111: 1092-1100, 2011</gamma(2)></p>10aab initio10abisphenyl10aoptical anisotropy10apolarizability10aPolycarbonate10astructure1 aSulatha, M., S.1 aNatarajan, U.  uhttps://library.ncl.res.in/content/ab-initio-calculations-geometry-and-polarizabilities-bisphenyls-having-aliphatic-002079nas a2200229   4500008004100000022001400041245013900055210006900194260007300263300001200336490000800348520116000356653001901516653002001535653005001555653002501605653001801630653003601648100002001684700002101704856012401725       2014                        eng d  a0926-860X00aEffects of method of preparation on catalytic activity of Co-Zn double-metal cyanide catalysts for copolymerization of CO2 and epoxide0 aEffects of method of preparation on catalytic activity of CoZn d  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcJUL  a300-3080 v4823 a<p>Co-Zn double-metal cyanide (DMC) complexes are well-known catalysts for ring-opening polymerization of epoxides and co-polymerization of CO2 and epoxides. This work provides an insight on structure-activity relationship of DMC for poly(cyclohexene carbonate) synthesis. Seven samples of DMC were prepared by different methods and mode of reagent addition. Highly active catalyst could be synthesized even without using a co-complexing agent. CO2 adsorption studies revealed that higher the guest-host interaction higher would be the catalytic activity. High density and strength of Lewis acid sites, moderate crystallinity, low crystal symmetry (rhombohedral/monoclinic), Cl- ions and coordinated tert.-butanol (complexing agent) control the catalytic activity for polycarbonates. Chloride in the structure avoided induction period by increasing acidity of the catalyst and thereby, improving the guest-host interactions. Polycarbonates with CO2 incorporation as high as 86 mol%, average molecular weight of 20900 and polydispersity index of 1.8 were prepared at complete conversion of cyclohexene oxide. (C) 2014 Elsevier B.V. All rights reserved.</p>10aCarbon dioxide10aCO2 utilization10aCopolymerization of CO2 and cyclohexene oxide10aDouble-metal cyanide10aPolycarbonate10aStructure-activity relationship1 aSebastian, Joby1 aSrinivas, Darbha  uhttps://library.ncl.res.in/content/effects-method-preparation-catalytic-activity-co-zn-double-metal-cyanide-catalysts-001775nas a2200205   4500008004100000022001400041245013400055210006900189260007300258300001200331490000800343520094400351653002001295653004101315653002501356653001801381100002001399700002101419856012901440       2015                        eng d  a0926-860X00aFactors influencing catalytic activity of Co-Zn double-metal cyanide complexes for alternating polymerization of epoxides and CO20 aFactors influencing catalytic activity of CoZn doublemetal cyani  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcOCT  a163-1720 v5063 a<p>Co-Zn double-metal cyanides (DMCs) show good catalytic activity towards copolymerization of epoxides and CO2. A deep insight into the structural aspects of the catalysts that control their catalytic performance is addressed in this work. Method of preparation of DMC catalysts was found to have influence on their structure, which in turn dictated their catalytic activity. Complexing agent (t-BuOH) and density of strong acid sites of DMC catalysts were found critical factors responsible for their activity. Selectivity of DMC towards polycarbonates depends on the amount of alkali ion content in their composition. Induction period of the catalysts was governed by the strength of acid sites and by the presence of dispersed ZnCl2 in the composition. This study provides an understanding of the prime features of DMC catalysts that can be tuned for high productivity of polycarbonates. (C) 2015 Elsevier B.V. All rights reserved.</p>10aCO2 utilization10aCopolymerization of epoxides and CO210aDouble-metal cyanide10aPolycarbonate1 aSebastian, Joby1 aSrinivas, Darbha  uhttps://library.ncl.res.in/content/factors-influencing-catalytic-activity-co-zn-double-metal-cyanide-complexes-alternating-002337nas a2200253   4500008004100000022001400041245006900055210006800124260000800192490000700200520155700207653001501764653001501779653002101794653001601815653001801831100002101849700003301870700001901903700002601922700001701948700002001965856009801985       2025                        eng d  a1864-563100aDepolymerization of waste polycarbonates to value-added products0 aDepolymerization of waste polycarbonates to valueadded products  cJAN0 v183 a<p>
	Additive free aminolysis method developed for the depolymerization/upcycling of polycarbonates. We report here chemical recycling of polycarbonate under ambient conditions to get its monomer bisphenol A, monoaminocarbamate and biscarbamates in 1 : 2 : 1 ratio respectively. By employing the secondary amine as the aminating reagent, facilitates the depolymerization to work under additive/catalyst free conditions. The developed method deals with depolymerization of waste polycarbonates and works even with late-stage amine derivatives such as amoxapine and desloratadine which are drugs molecules known to treat neurotic disorders and allergies respectively. The reaction can be scaled up and works with similar efficacy which depicts the efficiency of the depolymerization of wasteend-of-life polycarbonate plastic waste. The biscarbamate and bisphenol-A was further subjected for the post functionalization to obtain amides and phenol in good yields. Developed additive/catalyst free aminolysis of waste polycarbonates to carbamates and monomer BPA at ambient conditions. Variety of secondary amines were screened including the late stage amine derivatives like amoxapine and desloratadine which delivered the expected products successfully. Later the developed methodology was even applied for the different end-of-life polycarbonates with the secondary amine and achieved the depolymerization without any obstacle. Further carried out the scale up reaction and derivatization of carbamates and BPA to amide and phenol synthesis. image</p>
10aAminolysis10acarbamates10adepolymerization10aEnd-of-life10aPolycarbonate1 aPadhi, Ganeshdev1 aPansare, Vaibhav, Ramachandr1 aBajpai, Priyam1 aKrishna, Gamidi, Rama1 aVanka, Kumar1 aBarsu, Nagaraju  uhttps://library.ncl.res.in/content/depolymerization-waste-polycarbonates-value-added-products02648nas a2200241   4500008004100000022001400041245014700055210006900202260000800271300001100279490000800290520179100298653002302089653001302112653001802125653003302143100002402176700001802200700002102218700002502239700001902264856012302283       2026                        eng d  a0957-582000aSolvent-assisted chemical recycling of polycarbonate using glycerol as a renewable chemical: mechanistic insights and statistical optimization0 aSolventassisted chemical recycling of polycarbonate using glycer  cMAR  a1085920 v2093 a<p>
	The rapid accumulation of polycarbonate (PC) waste has driven the development of efficient recycling methods. This study presents a comprehensive investigation of solvent-assisted chemical recycling of PC using glycerol, a renewable chemical derived from industrial waste streams. Solvent screening highlighted the critical influence of solvent properties such as dielectric constant, dipole moment and hydrogen-bond accepting ability on depolymerization efficiency. A systematic approach combining Design of Experiments (DoE) and Response Surface Methodology (RSM) was employed to optimize the depolymerization process. Using a Box-Behnken design (BBD), the effects of key process parameters, including temperature, reaction time and the glycerol (GLY:PC) and dimethylformamide (DMF:PC) weight ratios, were evaluated in terms of PC conversion and bisphenol A (BPA) yield. The optimization model predicted that a reaction temperature of 171 degrees C, a reaction time of 1 h and a PC: GLY:DMF ratio of 1:5.05:7.22 would yield 100 % PC conversion and 85 % BPA yield. Experimental validation under these conditions achieved 100 % PC conversion and 83 % BPA yield, confirming the reliability of the model. Product characterization using NMR, LC-HRMS and FTIR confirmed the purity of BPA and provided insights into the reaction mechanism. The solvent recyclability across successive reaction cycles demonstrated the environmental and economic viability of the process. Overall, the energy demand calculation based on the environmental energy impact factor (xi) highlights the industrial relevance of this work and demonstrate an efficient and environmentally friendly catalyst-free route for depolymerization of polycarbonate with strong potential for industrial implementation.</p>
10aChemical Recycling10aGlycerol10aPolycarbonate10aResponse surface methodology1 aMarkandeya, Nishant1 aJadhav, Mayur1 aGopale, Prafulla1 aRamalingam, Karthick1 aKamble, Sanjay  uhttps://library.ncl.res.in/content/solvent-assisted-chemical-recycling-polycarbonate-using-glycerol-renewable-chemical