02173nas a2200193 4500008004100000022001400041245012500055210006900180260007100249300001600320490000800336520139700344100001501741700001901756700001701775700003201792700002501824856013001849 2008 eng d a1932-744700aSize dependent coordination behavior and cation distribution in MgAl2O4 nanoparticles from Al-27 solid state NMR studies0 aSize dependent coordination behavior and cation distribution in  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcSEP a14737-147440 v1123 a

Nanoparticles of spinel-type oxides such as ferrites offer great advantages and applications in many important areas. Decreasing the size of the particles to nanometer size will increase the surface-to-volume ratio and this will strongly influence the physical and chemical properties of these materials. For magnetic nanoparticles, the exchange interactions at the surface of a particle will be different from those inside due to changes in the coordination behavior at the surface. Therefore, studying and understanding the coordination and distribution behavior of the different metal ions in the nanoparticles of spinel-type oxides is very important. Solid state NMR is a useful and important technique to obtain information on local structural variations. The degree of the distribution of the Al3+ ions in the tetrahedral and octahedral sites in the nanoparticles of the nonmagnetic spinet MgAl2O4 having different particle sizes has been determined by Al-27 magic-angle spinning (MAS) NMR spectroscopy. It has been observed that the inversion parameter decreases with increasing particle size. Apart from the usual tetrahedral and octahedral coordinations present in the bulk material, the presence of five- and three-coordinated At has been observed in nanoparticles with sizes less than 18 nm and a second octahedral coordination is observed for nanoparticles of larger sizes.

1 aSreeja, V.1 aSmitha, T., S.1 aNand, Deepak1 aAjithkumar, Thalasseril, G.1 aJoy, Pattayil, Alias uhttps://library.ncl.res.in/content/size-dependent-coordination-behavior-and-cation-distribution-mgal2o4-nanoparticles-al-27-001814nas a2200241 4500008004100000022001400041245011200055210006900167260007300236300001200309490000800321520088500329653002101214653002301235653003001258653002201288653002201310100002401332700002501356700003201381700002801413856013101441 2014 eng d a0926-860X00aSBA-15 intercalated Mg-Al hydrotalcite: an environmental friendly catalyst for hydroisomerization of olefin0 aSBA15 intercalated MgAl hydrotalcite an environmental friendly c aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcNOV a119-1270 v4883 a

SBA-15 Molecular sieve-intercalated Mg-Al hydrotalcite (MASBA-HT) was synthesized for the first time by a simple straightforward method. The intercalation of SBA-15 molecular sieve between the interlayer of HT was evident from powder XRD, TEM and FT-IR studies. The presence of SBA-15 facilitates retention of the layered structure for first time, even after calcination at high temperature of 550 degrees C. The resultant material possesses moderate acidity which comes from incorporation of aluminum into the framework of SBA-15 and also contained soluble basicity similar to HT materials. The material shows promising activity for hydroisomerization of 1-octene resulting in good substrate conversion (80%) and branched isomers selectivity (45%). The catalytic activity remains constant over longer duration and repeated runs. (C) 2014 Elsevier B.V. All rights reserved.

10aBranched alkenes10aHydroisomerization10aIntercalated-hydrotalcite10alayered materials10aMesoporous SBA-151 aBaskaran, Thangaraj1 aChristopher, Jayaraj1 aAjithkumar, Thalasseril, G.1 aSakthivel, Ayyamperumal uhttps://library.ncl.res.in/content/sba-15-intercalated-mg-al-hydrotalcite-environmental-friendly-catalyst-hydroisomerization-001926nas a2200181 4500008004100000022001400041245015300055210006900208260007100277300001400348490000800362520113900370100002101509700003201530700002401562700003001586856012801616 2014 eng d a1089-563900aSolid-state NMR investigations of a MgCl2 center dot 4(CH3)(2)CHCH2OH molecular adduct: a peculiar case of reversible equilibrium between two phases0 aSolidstate NMR investigations of a MgCl2 center dot 4CH32CHCH2OH a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcFEB a1213-12190 v1183 a

MgCl2 center dot xROH molecular adducts are extensively employed as a support material for Ziegler-Natta polyolefin catalysis. However, their structural properties are not well understood. Recently, we reported on the preparation of an isobutanol adduct, MgCl2 center dot 4(CH3)(2)CHCH2OH (MgiBuOH) (Dalton Trans. 2012, 41, 11311), which is very sensitive to the preparation conditions, such as the temperature and refluxing time. For the present study, the structural properties of MgiBuOH adducts prepared under different conditions have been investigated thoroughly by solid-state NMR and nonambient XRD. Formation of two phases has been confirmed, and in situ variable temperature solid-state NMR measurements confirm the coexistence of two phases as well as the oscillation from one to another phase. It is expected that such molecular adducts could have a significant role in organic transformation reactions due to an oscillating structural component. An understanding of phase oscillation with the Mg2+ ion as the central metal ion might shed some light toward understanding various biological and structural functions.

1 aThushara, K., S.1 aAjithkumar, Thalasseril, G.1 aRajamohanan, P., R.1 aGopinath, Chinnakonda, S. uhttps://library.ncl.res.in/content/solid-state-nmr-investigations-mgcl2-center-dot-4ch32chch2oh-molecular-adduct-peculiar-001693nas a2200253 4500008004100000022001400041245011000055210006900165260007300234300001200307490000800319520077400327653002801101653001001129653002101139653000801160653001501168653002701183100002101210700003201231700002401263700003001287856012201317 2014 eng d a0926-860X00aStructural investigations of porous MgCl2-2-butanol molecular adduct as support for olefin polymerization0 aStructural investigations of porous MgCl22butanol molecular addu aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcJAN a267-2740 v4693 a

A new heterogeneous Ziegler-Natta (Z-N) catalyst support material, MgCl2 center dot 4(CH3CH(OH)CH2CH3) (Mg2BuOH) has been synthesized. 2-Butanol, a linear, secondary alcohol was chosen for the generation of an active MgCl2 support which results in a Z-N catalyst with TiCl4. Significant feature of this work is the formation of rod shaped molecular adduct with highly porous character. Adduct material is characterized by XRD, TG-DTA, Raman spectroscopy, solid-state NMR and SEM. Activity of the Z-N catalyst supported on Mg2BuOH for ethylene polymerization is comparable with that of commercially available heterogeneous Z-N catalyst. However, there is scope to improve the activity by optimizing textural properties. (C) 2013 Elsevier B.V. All rights reserved.

10aheterogeneous catalysis10aMgCl210aMolecular adduct10aNMR10aPolyolefin10aZiegler-Natta catalyst1 aThushara, K., S.1 aAjithkumar, Thalasseril, G.1 aRajamohanan, P., R.1 aGopinath, Chinnakonda, S. uhttps://library.ncl.res.in/content/structural-investigations-porous-mgcl2-2-butanol-molecular-adduct-support-olefin-002134nas a2200265 4500008004100000022001400041245010400055210006900159260007300228300001200301490000800313520113300321653006501454653003301519653002501552100002201577700002201599700001801621700001201639700001701651700002401668700003201692700001701724856012701741 2015 eng d a0022-311500aStudy on fused/cast AZS refractories for deployment in vitrification of radioactive waste effluents0 aStudy on fusedcast AZS refractories for deployment in vitrificat aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcDEC a144-1540 v4673 a

Fused/cast Al2O3-ZrO2-SiO2 (FC-AZS)' is being considered as `glass contact refractory' within ceramic melters, to be used for nuclear waste immobilization. Microstructural analyses reveal random distributions of baddeleyite (ZrO2) within aluminosilicate (Al2SiO5) matrix. Al-27 and Si-29 NMR data suggest that within aluminosilicate matrix Al occurs in both 4- and 6-fold co-ordinations whereas Si prefers a 4-fold environment. Polydispersity of pores has been studied with small-angle neutron scattering (SANS) technique. Corrosion rates of FC-AZS within 6 M HNO3, simulated wastes (500 h exposure), and borosilicate melt (975 degrees C, 800 h exposure) are found to be 0.38 x 10(3) mu my(-1), 0.13 x 10(3) mu my(-1) and 4.75 x 10(3) mu my(-1) respectively. A comparison of chemical interaction data clearly suggests that FC-AZS exhibits better chemical durability than AZC refractory (Al2O3-ZrO2-Cr2O3, also used for similar purpose). Thermal cycling studies indicate that FC-AZS retains structural integrity (including compressive strength and density) even up to 20 cycles. (C) 2015 Elsevier B.V. All rights reserved.

10aInteraction between refractory material and hazardous liquid10aNuclear waste immobilization10aVitrification melter1 aSengupta, Pranesh1 aMishra, Raman, K.1 aSoudamini, N.1 aSen, D.1 aMazumder, S.1 aKaushik, Chetan, P.1 aAjithkumar, Thalasseril, G.1 aBanerjee, K. uhttps://library.ncl.res.in/content/study-fusedcast-azs-refractories-deployment-vitrification-radioactive-waste-effluents-001538nas a2200229 4500008004100000022001400041245011100055210006900166260000900235300001200244490000700256520072700263653002300990653002001013653002201033653001301055100003001068700003201098700002301130700002801153856012701181 2015 eng d a1566-736700aSupported imidazole as heterogeneous catalyst for the synthesis of cyclic carbonates from epoxides and CO20 aSupported imidazole as heterogeneous catalyst for the synthesis  cJAN  a201-2050 v593 a

Imidazole anchored onto a silica matrix, by means of a propyl linkage, is found to be an effective heterogeneous catalyst for the synthesis of cyclic carbonates from epoxides and CO2 in near quantitative yield. The versatility of this catalyst is demonstrated by using different substrates (epichlorohydrin, propylene oxide, butylene oxide and styrene oxide) for this cycloaddition reaction. These CO2 insertion reactions were typically carried out in the temperature range of 343 to 403 K at 0.6 MPa CO2 pressure under solvent-free conditions. Several spectroscopic methods were used to characterize the catalyst and study the integrity of the fresh and spent catalysts. (C) 2014 Elsevier B.V. All rights reserved.

10aAnchored imidazole10aCO2 utilization10acyclic carbonates10aepoxides1 aSankar, Meenakshisundaram1 aAjithkumar, Thalasseril, G.1 aSankar, Gopinathan1 aManikandan, Palanichamy uhttps://library.ncl.res.in/content/supported-imidazole-heterogeneous-catalyst-synthesis-cyclic-carbonates-epoxides-and-co202583nas a2200253 4500008004100000022001400041245011100055210006900166260000800235300001600243490000700259520168600266100002001952700001701972700001801989700002202007700002402029700003202053700003202085700002702117700003202144700002302176856013002199 2026 eng d a2470-134300aSustainable nanocellulose extraction from salacca zalacca peel using chlorine-free and low-acid treatments0 aSustainable nanocellulose extraction from salacca zalacca peel u cMAR a13253-132670 v113 a

Conversion of agro-waste to value-added products is one of the important principles of a green circular economy. A novel sustainable technique has been reported by using chlorine-free extraction of cellulose nanofibers (CNFs) from the peels of Salacca zalacca, a common fruit found in Asia. The fruit peels were exposed to alkali treatment using 2% NaOH (60 degrees C, 2 h), chlorine-free bleaching using 15% hydrogen peroxide (60 degrees C, 2 h), and sulfuric acid hydrolysis (15% v/v) for the extraction of CNFs. Various analytical methods were employed to characterize the prepared CNFs. The Fourier transform infrared spectroscopy (FTIR) and 13C solid state nuclear magnetic resonance (NMR) spectra showed the complete elimination of lignin and hemicellulose in the prepared CNFs. The elemental composition and high purity of CNFs were further verified by energy-dispersive X-ray analysis (EDX). The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images proved the fibrous morphology of the prepared CNFs, and the diameters of the cellulose nanofibers were found to be 15-30 nm. The X-ray diffraction (XRD) studies disclosed the type-I cellulosic structure in the prepared CNFs with a high crystallinity index (73%). The thermogravimetric analysis (TGA) demonstrated the superior thermal stability of the prepared CNFs (T max is 350 degrees C) compared to the raw fiber (T max is 320 degrees C). Based on the obtained results, it has been explored that the extracted highly pure CNFs can be used for fabricating bionanocomposites for high performance applications, including food packaging, sensors, water treatment, green tires, etc.

1 aKrishnan, Akhil1 aPaul, Sharon1 aPhiri, Resego1 aSrisuk, Rapeeporn1 aSingh, Manoj, Kumar1 aPalaniappan, Sathish, Kumar1 aRangappa, Sanjay, Mavinkere1 aDominic, C., D. Midhun1 aAjithkumar, Thalasseril, G.1 aSiengchin, Suchart uhttps://library.ncl.res.in/content/sustainable-nanocellulose-extraction-salacca-zalacca-peel-using-chlorine-free-and-low-acid