@article {43391, title = {Isohexide-diacetal based polymers and a process thereof}, number = {PCT/IN2014/000318}, year = {2014}, month = {NOV}, abstract = {

The present invention discloses isohexide based compounds and their polymers which are derived from renewable resources and are potentially degradable. Also disclosed herein is the synthesis of isohexide based monomers and their polymers from renewable resources which are potentially degradable. Further, the present invention disclose a process for the synthesis of isohexide based copolymers via copolymerization of isohexide based monomers and long chain diols, which are degradable. (FR)Cette invention concerne des compos{\'e}s {\`a} base d{\textquoteright}isohexide et leurs polym{\`e}res qui sont d{\'e}riv{\'e}s de ressources renouvelables et sont potentiellement d{\'e}gradables. Cette invention concerne {\'e}galement la synth{\`e}se de monom{\`e}res {\`a} base d{\textquoteright}isohexide et leurs polym{\`e}res {\`a} partir de ressources renouvelables qui sont potentiellement d{\'e}gradables. Un proc{\'e}d{\'e} de synth{\`e}se de copolym{\`e}res {\`a} base d{\textquoteright}isohexide par copolym{\'e}risation desdits monom{\`e}res {\`a} base d{\textquoteright}isohexide et de diols {\`a} cha{\^\i}ne longue, qui sont d{\'e}gradables, est en outre d{\'e}crit.

}, author = {Chikkali, Samir H. and Rajput, Bhausaheb S.} } @article { ISI:000380018700009, title = {Synthesis of renewable copolyacetals with tunable degradation}, journal = {Macromolecular Chemistry and Physics}, volume = {217}, number = {12}, year = {2016}, month = {JUN}, pages = {1396-1410}, publisher = {WILEY-V C H VERLAG GMBH}, address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY}, abstract = {

Acetal metathesis copolymerization (AMCP) of renewable isohexide diacetals and aliphatic long-chain diacetals is reported and access to a small family of copolyacetals has been established. Crucial 1-2D NMR and MALDI-ToF-MS findings unambiguously confirm the existence of a copolymeric structure. In a stark contrast to the earlier reported isohexide-polyacetals, the current copolyacetals reveal very slow degradation. Hydrolytic degradation of copolyacetal pellets is extremely slow at pH 7, whereas only 30\% degradation over a period of 15 d is observed in 9 M hydrochloric acid solution. GPC investigations reveal that with increasing chain-length the rate of degradation reduces, whereas copolyacetals with short-chain aliphatic segments display a faster degradation profile. The reduced rate of degradation can be attributed to the hydrophobic nature of long-chain acetal segments. In situ NMR spectroscopy reveals the existence of formates, hemiacetals, and diols as degradation products. Thus, the rate of degradation can be tuned by the judicious choice of isohexide-diacetal and linear-diacetals in a copolyacetal.

}, keywords = {copolyacetals, degradable polymers, diacetals, isohexides, renewable polymers}, issn = {1022-1352}, doi = {10.1002/macp.201600071}, author = {Rajput, Bhausaheb S. and Chander, Umesh and Arole, Kailash and Stempfle, Florian and Menon, Shamal K. and Mecking, Stefan and Chikkali, Samir H.} } @article {43893, title = {Synthesis of isohexide-di(ether-ene)s and ADMET polymerization}, journal = {Green Materials}, volume = {5}, year = {2017}, month = {JUN}, type = {Article}, abstract = {As the fossil fuel reserves deplete and the greenhouse gases increase, the scientific community is challenged to provide sustainable solutions. Sugar-based isohexides can be modified to prepare a library of isohexide-diene monomers for polymerization. Such isohexide diene monomers can be subjected to Acyclic Diene Metathesis Polymerization to obtain green materials. Here we report a single step synthetic protocol to access a small family of isohexide-di(ether-ene)s and the corresponding polymers. The isohexide di(ether-ene)s 2a-2c could be isolated in good to excellent yields under optimized conditions. The resultant isohexide-di(ether-ene)s 2a-2c are potential versatile building blocks for pharmaceuticals and material science. The synthetic utility of 2a-2c was demonstrated by subjecting them to ADMET polymerization using Grubbs 1st and 2nd generation catalysts. The resultant viscous material was evaluated using 1H NMR and MALDI-ToF-MS, which suggests the formation of anticipated ADMET polymers}, doi = {10.1680/jgrma.16.00017}, author = {Rajput, Bhausaheb S. and Lekshmy, Kalpakasseril Girija and Menon, Shamal K. and Chikkali, Samir H.} } @article {44443, title = {Cross-metathesis of biorenewable dioxalates and diols to film-forming degradable polyoxalates}, journal = {Journal of Polymer Science Part A-Polymer Chemistry}, volume = {56}, year = {2018}, month = {JUL}, pages = {1584-1592}, abstract = {Starting from commonly available sugar derivatives, a single step protocol to access a small family of isohexide-dioxalates (2a-c) has been established. The synthetic competence of 2a-c has been demonstrated by subjecting them to condensation polymerization. Quite surprisingly, the proton NMR of poly(isomannide-co-hexane)oxalate revealed a 1:2 ratio between isomannide-dioxalate (2a) and 1,6-hexanediol (3a) in the polymer backbone. This intriguing reactivity was found to be an outcome of a cross metathesis reaction between 2a and 3a. The cross metathesis products 3a[2-(2-methoxyacetoxy)ethyl 2-(2-hydroxyethoxy)-2-(3-oxydanylidene)acetate] and 2a(3R,6R)-6-hydroxyhexahydrofuro[3,2-b]-furan-3-yl methyl oxalate were isolated in a control experiment. Based on direct and indirect evidence, and control experiments, an alternative polymerization mechanism is proposed. Polymerization conditions were optimized to obtain polyoxalates P1(2a-3a)-P9(2c-3c) with molecular weights in the range of 14,000-68,000 g/mol, and narrow polydispersities. The identity of the polyoxalates was unambiguously established using 1-2D NMR spectroscopy, MALDI-ToF-MS, and GPC measurements. The practical implication of these polymers is demonstrated by preparing transparent, mechanically robust films. The environmental footprint of the selected polyoxalates was investigated by subjecting them to solution and solid-state degradation. The polyoxalates were found to be amenable to degradation. (c) 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 1584-1592}, doi = {10.1002/pola.29043}, author = {Rajput, Bhausaheb S. and Ram, Farsa and Menon, Shamal K. and Shanmuganathan, Kadhiravan and Chikkali, Samir H.} } @article {46797, title = {Renewing polyethylene: insertion copolymerization of sugar derived hydrophilic monomers with ethylene}, journal = {European Polymer Journal}, volume = {134}, year = {2020}, month = {JUL }, pages = {109775}, type = {Article}, abstract = {

Although highly desirable, insertion copolymerization of renewable resource derived functional olefins with ethylene has been rarely investigated. Herein, we report insertion copolymerization of challenging sugar derived isohexide mono-enes with ethylene in the presence of Pd-phosphinesulfonate acetonitrile catalyst (C1). Thus, copolymerization of ethylene with isomannide mono-ene (2a), isosorbide mono-ene (2b{\textquoteright}), isoidide mono-ene (2c) and methacryl-2,3,4,6-tetra-O-acetyl-D glucopyranoside (2d) afforded corresponding functionalized polyethylene (P2a-1 to P2d-1). High temperature proton NMR investigations revealed enchainment of 2a-2c in polyethylene backbone and the highest incorporation of 1.45\% was observed for 2c. The high temperature proton NMR results were further corroborated by solid state C-13 NMR and IR spectroscopy. Gel permeation chromatography analysis displayed weight average molecular weight in the range of 13.0-27.2 x 10(3) g/mol. The thus prepared copolymers revealed melting temperature in the range of 117-126 degrees C. Relatively reduced melting temperature compared to neat polyethylene may suggest an irregular arrangement of pendant functional group on polyethylene main chain.

}, keywords = {Hydrophilic polyethylene, insertion copolymerization, Isohexide mono-enes, Polyethylene, Sugar}, issn = {0014-3057}, doi = {10.1016/j.eurpolymj.2020.109775}, author = {Rajput, Bhausaheb S. and Pawal, Sandip B. and Bodkhe, V. Dnyaneshwar and Rao, I. Nagamalleswara and Sainath, Annadanam V. Sesha and Chikkali, Samir H.} } @article {47361, title = {Refining plant oils and sugars to platform chemicals, monomers, and polymers}, journal = {Green Chemistry}, volume = {23}, year = {2021}, month = {MAY}, pages = {4255-4295}, type = {Review}, abstract = {

As fossil resources continue to dwindle and environmental concerns are magnified, finding sustainable alternatives is the only way to mitigate resource availability and derisk the planet. The principles of Green Chemistry may provide guidance in this case, and renewable resources can be converted into useful platform chemicals, monomers, and polymers. This critical review examines the possibility of utilizing renewable plant oils and sugars to produce feedstock chemicals, monomers, and polymers. Among the seven isomerizing functionalization reactions of plant oils, isomerizing alkoxycarbonylation displays the highest terminal selectivity. Despite the low reactivity of sugar-derived isohexides, new strategies have been deployed to convert isohexides into difunctional monomers and polymers. The commercialization of isohexides and a few polymers derived from these building blocks has just commenced. Thus, challenges associated with isomerizing functionalization of plant oils and the use of sugar-derived isohexides in chemical syntheses have been summarized, and the potential of these renewable resources has been evaluated.

}, issn = {1463-9262}, doi = {10.1039/d1gc00955a, Early Access Date = MAY 2021}, author = {Pandey, Swechchha and Rajput, Bhausaheb S. and Chikkali, Samir H.} }