NOPR Collection:

Synthesis, characterization and thermal decomposition of di-(2,4,6-trimethylanilinium) sulphate

2010-08-21T16:30:52Z

Title: Synthesis, characterization and thermal decomposition of di-(2,4,6-trimethylanilinium) sulphate Authors: Kapoor, Inder Pal Singh; Kapoor, Manisha; Singh, Gurdip; Fröhlich, Roland Abstract: Di-(2,4,6-trimethylanilinium) sulphate [2,4,6-TMAS] was synthesized by reaction of 2,4,6-trimethylaniline with concentrated sulphuric acid at room temperature. The crystal structure of this salt was determined using single crystal X-ray diffraction. It crystallizes in orthorhombic space group Pna2₁, a= 7.7115(1) Å, b= 30.3746 (6) Å, c=16.9251 (3)Å , ==[°]=90°, V=3964.43 (12)A and Z=8. The structure contains 2,4,6-trimethylanilinium ions that share vertices through intermolecular H- bonds with sulphate ions and a water molecule. Notably thermal and microwave heatings of di-(2,4,6-TMA)S have afforded 3-amino-2,4,6-trimethylbenzenesulphonic acid (3-A-2,4,6-TMBSA) with release of a molecule of amine and water. It has been suggested that the proton transfer from anilinium to SO₄^2-ion is a primary and rate controlling step. Further di-(2,4,6-TMA)S and 3-A-2,4,6-TMBSA were characterized by infrared, mass spectrometry, elemental and thermogravimetric- differential scanning calorimetric (TG-DSC) analyses. The mean value for the energy of activation (83.0 kJ mol^-1) for the conversion of di-(2,4,6-TMA)S to 3-A-2,4,6-TMBSA has been determined from isothermal thermogravimetry data. Page(s): 305-310

Characterization, dielectric and optical studies of nano-cerium phospho iodate synthesized by chemical co-precipitation method

2010-08-24T16:30:13Z

Title: Characterization, dielectric and optical studies of nano-cerium phospho iodate synthesized by chemical co-precipitation method Authors: Indulal, C R; Vaidyan, A V; Kumar, G Sajeev; Raveendran, R Abstract: Nanoparticles of cerium phospho iodate belong to the class of tetravalent metal acid (TMA) salt are synthesized by chemical co-precipitation method. The particle size obtained from X-ray diffraction spectrum is found to be in the range of 30 nm. Surface morphology is studied from SEM images. The chemical composition of the sample has been verified using EDAX. The optical studies are carried out using FTIR and UV techniques. The stretching and bending frequencies of the sample are studied using the FTIR spectrum. The optical direct band gap of the material calculated using the Tauc’s relation is found to be 3.4 eV. The dielectric behaviour of the samples is studied at various temperatures and frequencies and ac electrical conductivity is also calculated. It is found that dielectric constant decreases with increase in frequency. Page(s): 299-304

Preparation and studies of chemically deposited Cu₄SnS₄thin films in the presence of complexing agent Na₂EDTA

2010-08-17T16:30:38Z

Title: Preparation and studies of chemically deposited Cu₄SnS₄thin films in the presence of complexing agent Na₂EDTA Authors: Kassim, Anuar; Kuang, Zulkefly; Sharif, Atan; Tee, Tan Wee; Min, Ho Soon; Nagalingam, Saravanan Abstract: The Cu₄SnS₄ thin films are deposited onto indium tin oxide glass substrate by chemical bath deposition method. The disodium ethylenediaminetetraacetic acid is used as a complexing agent during deposition process. The structural, morphological and optical properties of the deposited films have been studied using X-ray diffraction, atomic force microscopy and UV-Vis spectrophotometer, respectively. The presence of Na₂EDTA promotes the deposition of better quality films. The XRD analysis shows that these films have a high crystallinity with orthorhombic structure. The AFM images indicated that these films are uniform, compact with larger grains. The absorption spectra confirmed that the thicker film has higher absorption properties. The band gap of 1.6 eV with direct transition is observed. Page(s): 295-298

Microstructure of 2 and 28-day cured Portland limestone cement pastes

2010-08-19T16:30:13Z

Title: Microstructure of 2 and 28-day cured Portland limestone cement pastes Authors: Sezer, Gözde İnan; Çopuroğlu, Oğuzhan; Ramyar, Kambiz Abstract: In this study, microstructures of limestone cement pastes cured for 2 and 28 days are investigated. For this purpose, limestone and clinker are separately ground in a ball-mill until obtained a given constant 32 µm sieve residue. The gypsum is kept constant as 5% by weight of cement. Cement pastes with 0.5 water/binder ratios and 0, 6, 35% limestone/clinker ratios are prepared. After 2 and 28 days standard curing, ESEM investigations are carried out on these specimens. It is found that hydration products are accumulated around limestone particles. In 2 days, compared to the control specimen, pore percentages of cements containing 6% limestone are decreased whereas pore percentages of cement pastes containing 35% limestone are increased. The difference between porosities of the control paste and limestone cement paste is decreased at 28 days. Page(s): 289-294

NOPR Collection:

Synthesis, characterization and thermal decomposition of di-(2,4,6-trimethylanilinium) sulphate

Characterization, dielectric and optical studies of nano-cerium phospho iodate synthesized by chemical co-precipitation method

Preparation and studies of chemically deposited Cu4SnS4 thin films in the presence of complexing agent Na2EDTA

Microstructure of 2 and 28-day cured Portland limestone cement pastes

Preparation and studies of chemically deposited Cu₄SnS₄thin films in the presence of complexing agent Na₂EDTA