02642nas a2200229 4500008004100000022001400041245007700055210006900132260007100201300001200272490000600284520184300290653002202133653001202155653002602167653002102193653001102214653002502225100002402250700002902274856010902303 2015 eng d a2155-543500aLignin depolymerization into aromatic monomers over solid acid catalysts0 aLignin depolymerization into aromatic monomers over solid acid c a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcJAN a365-3790 v53 a

It is imperative to develop an efficient and environmentally benign pathway to valorize profusely available lignin, a component of nonedible lignocellulosic materials, into value-added aromatic monomers, which can be used as fuel additives and platform chemicals. To convert lignin, earlier studies used mineral bases (NaOH, CsOH) or supported metal catalysts (Pt, Ru, Pd, Ni on C, SiO2, Al2O3, etc.) under a hydrogen atmosphere, but these methods face several drawbacks such as corrosion, difficulty in catalyst recovery, sintering of metals, loss of activity, etc. Here we show that under an inert atmosphere various solid acid catalysts can efficiently convert six different types of lignins into value-added aromatic monomers. In particular, the SiO2Al2O3 catalyst gave exceptionally high yields of ca. 60% for organic solvent soluble extracted products with 95 +/- 10% mass balance in the depolymerization of dealkaline lignin, bagasse lignin, and ORG and EORG lignins at 250 degrees C within 30 min. GC, GC-MS, HPLC, LC-MS, and GPC analysis of organic solvent soluble extracted products confirmed the formation of aromatic monomers with ca. 90% selectivity. In the products, confirmation of retention of aromatic nature as present in lignin and the appearance of several functional groups has been carried out by FT-IR and H-1 and C-13 NMR studies. Further, isolation of major products by column chromatography was carried out to obtain aromatic monomers in pure form and their characterization by NMR is presented. A detailed characterization of six different types of lignins obtained from various sources helped in substantiating the catalytic results obtained in these reactions. A meticulous study on fresh and spent catalysts revealed that the amorphous catalysts are preferred to obtain reproducible catalytic results.

10aaromatic monomers10aBiomass10acolumn chromatography10adepolymerization10alignin10asolid acid catalysts1 aDeepa, Ayillath, K.1 aDhepe, Paresh, Laxmikant uhttps://library.ncl.res.in/content/lignin-depolymerization-aromatic-monomers-over-solid-acid-catalysts-001988nas a2200193 4500008004100000022001400041245011600055210006900171260000800240520124700248653003901495653002101534653003801555653001601593653001101609100002201620700002201642856013001664 2019 eng d a1877-264100aFormic-acid-induced using recyclable-ionic liquids as catalysts for lignin conversion into aromatic co-products0 aFormicacidinduced using recyclableionic liquids as catalysts for cNOV3 a

Lignin has been widely named as a sustainable and renewable bioresource of energy, fuels, chemicals and materials, particularly phenolic chemicals production on Earth. These bio-derived compounds are in great potential need of biorefinery to valorize complete plant biomass. Lignin depolymerization showed a great promise approach to convert into low molecular aromatic products. In this report, high molecular weight (54,000 Da) lignin depolymerization into maximum yields (87%), (>= 95 +/- 6% mass balance) using a formic acid along with dual (-SO3H) functionalized imidazole-based recyclable (4 times) Bronsted acidic ionic liquids (BAILs) as catalysts have been investigated in H2O-CH3OH (1:5, v/v) at 120 degrees C for 1 h. The structural correlations between the lignin and aromatic products were studied by bulk (CHNS, GPC, etc.) and molecular (UV-Vis, FT-IR, NMR (1D/2D) levels experimental techniques. Additionally, the identification of aromatic products was carried out by applying HPLC, GC and GC-MS techniques. Graphic Addition of a formic acid into Bronsted acidic ionic liquids improved the catalytic efficiency significantly for lignin depolymerization into 87% low molecular weight aromatic products. [GRAPHICS] .

10aBulk and molecular levels analysis10adepolymerization10aDual functionalized ionic liquids10aFormic acid10alignin1 aSingh, Sandip, K.1 aDhepe, Paresh, L. uhttps://library.ncl.res.in/content/formic-acid-induced-using-recyclable-ionic-liquids-catalysts-lignin-conversion-aromatic-co00825nas a2200229 4500008004100000022001400041245012100055210006900176260001000245300001600255490000700271653001600278653002800294653002100322653001900343653002500362100002600387700002100413700001800434700002000452856012300472 2024 eng d a2168-048500aCopper/Iron cocatalyzed depolymerization of postconsumer polycarbonate: a one-pot strategy to synthesize aryl ethers0 aCopperIron cocatalyzed depolymerization of postconsumer polycarb cDEC 7 a18362-183720 v1210aaryl ethers10acopper/iron cocatalysis10adepolymerization10apolycarbonates10aValue-added products1 aMoyilla, Nageswararao1 aPadhi, Ganeshdev1 aKalsi, Deepti1 aBarsu, Nagaraju uhttps://library.ncl.res.in/content/copperiron-cocatalyzed-depolymerization-postconsumer-polycarbonate-one-pot-strategy02612nas a2200241 4500008004100000022001400041245008600055210006900141260000900210490000700219520183600226653002502062653001102087653001802098653002102116653002302137653002002160653001902180100001702199700001902216700002402235856011102259 2024 eng d a1867-388000aIron in organometallic transformations: a sustainable substitute for noble metals0 aIron in organometallic transformations a sustainable substitute  cOCT 0 v163 a

Transition metal catalysis plays a pivotal role in chemical synthesis. Noble metals often grab significant attention in organometallic catalysis due to their high reactivity. However, the serious issues associated with these metals such as low abundance, toxicity, geopolitical limitations, and volatile prices are driving the scientific community to discover sustainable alternatives. In this context, iron appears to be the first choice as an alternative metal due to its unique properties, including a range of stable oxidation states, Lewis acidity, high abundance in the earth's crust, and low toxicity. Over the past two decades, substantial progress has been made in iron catalysis. This overview examines the recent developments in iron-catalyzed industrially relevant transformations such as hydroformylation, olefin isomerization, hydrosilylation, hydrophosphination, carbonylation, Wacker-type oxidation, and plastic depolymerization. As witnessed throughout this review, the performance of iron can be significantly altered by suitable ligand selection and by tailoring the electronic and steric properties of the iron center. While noble metals remain the industry work-horse, iron is inching closer and with extensive scientific understanding, it may replace noble metals in the near future. Late transition metals catalyze several reactions and have been the industry work-horse for decades. While, earth abundant metals are rarely used in industrially relevant transformations. In this overview, we examine the recent development in iron-catalyzed industrially relevant reactions such as hydroformylation, olefin isomerization, hydrosilylation, hydrophosphination, carbonylation, Wacker-type oxidation, and plastic depolymerization. Iron is inching closer and may replace noble metals in near future. image

10aAlkene Isomerization10aalkyne10aCarbonylation10adepolymerization10aHydrophosphination10aHydrosilylation10airon catalysis1 aKumar, Rohit1 aTewari, Tanuja1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/iron-organometallic-transformations-sustainable-substitute-noble-metals02337nas a2200253 4500008004100000022001400041245006900055210006800124260000800192490000700200520155700207653001501764653001501779653002101794653001601815653001801831100002101849700003301870700001901903700002601922700001701948700002001965856009801985 2025 eng d a1864-563100aDepolymerization of waste polycarbonates to value-added products0 aDepolymerization of waste polycarbonates to valueadded products cJAN0 v183 a

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

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-products02092nas a2200229 4500008004100000022001400041245009700055210006900152260000900221300001200230490000700242520133000249653002101579653002301600653001501623653001401638653002501652100002001677700001901697700002101716856012501737 2025 eng d a1060-132500aWaste polyethylene to long-chain unsaturated esters and alcohols via alkene cross-metathesis0 aWaste polyethylene to longchain unsaturated esters and alcohols  cAUG  a660-6680 v623 a

The conversion of waste polyethylene into valuable long-chain functional molecules offers a contemporary solution to the global plastic waste challenge. This study presents a two-step catalytic approach, comprising of polyethylene (PE) dehydrogenation followed by cross-metathesis with renewable resource-derived functional olefins, catalyzed by the Grubbs-II catalyst (G-II). A dehydrogenated polyethylene (DHP) was subjected to a tandem catalytic cross-alkene metathesis with functional olefins under mild conditions to achieve approximately 36% conversion of DHP into valuable long-chain building blocks with controlled product distribution. Comprehensive characterization of intermediates and products was performed using NMR, GC, GC-MS, GPC, and DSC. In the alkene cross-metathesis with methyl-10-undecenoate, the product distribution consisted of 23% lower alkenes (C8-C14), 40% unsaturated long-chain mono-esters (C12-C18), and 37% unsaturated di-esters. In the case of 10-undecen-1-ol, the distribution included 20% lower alkenes (C8-C11), 32% unsaturated long-chain (C12-C18) mono-alcohols, and 48% unsaturated di-alcohols. This strategy opens up new opportunities for converting waste polyethylene into high-value chemical intermediates, enabling resource recovery and delivering environmental benefits.

10adepolymerization10afunctional olefins10aMetathesis10aRecycling10aValue-added products1 aKhopade, K., V.1 aBodkhe, D., V.1 aChikkali, S., H. uhttps://library.ncl.res.in/content/waste-polyethylene-long-chain-unsaturated-esters-and-alcohols-alkene-cross-metathesis