The Reaction of Organo-Selenium and -Tellurium Compounds with Dihalogens,Interhalogens, and Pseudohalogens

Adducts of selenium and tellurium donor molecules with dihalogens, interhalogens, and pseudohalogens exhibit a remarkable structural diversity. Some interesting examples of these materials and key factors influencing their formation, structures, and bonding are discussed.     

Enhanced grain growth and improved optical properties of the Sn doped thin films of Sb2S3 orthorhombic phase

The applications of newer Sb₂S₃ material as a suitable absorber material for the solar cells have been effected by the toxicity of Sb. The present study is an effort to synthesize lower Sb contents Sn doped Sb₂S₃ materials by retaining or improving the morphological and optical properties. SnCl₂ and SbCl₃ are used respectively as Sn and Sb sources, while Na₂S₂O₃ has been used as a source of S in chemical bath deposition method. Bath temperature was maintained at 10 °C and the deposition time was 4 h and the annealing of the films in vacuum was done for 2 h at 250 °C. X-ray diffraction, Rutherford backscattering spectroscopy, scanning electron microscopy and ultraviolet/visible light spectroscopy have been used for the study of structural, morphological and the optical properties. The chemical composition determined from RBS is Sn_0.11Sb₂S₃. Phase analysis confirms the orthorhombic Sb₂S₃ phase with b and c axis as the preferred ones for the impurity Sn atoms. Grain growth at lower deposition temperature is enhanced on the account of doping. Nanosized spherical particles are seen in the optical micrographs. Annealing lowers the band gap, the values being 1.50 and 1.31 eV for the unannealed and the annealed samples respectively.     

Influence of PZC (Point of Zero Charge) on the Static Adsorption of Anionic Surfactants on a Malaysian Sandstone

Static adsorption studies of two anionic surfactants produced in our lab are reported. The adsorption of surfactants on the rock samples was investigated with and without the presence of alkali. The point of zero charge (PZC) values were determined for the sandstone samples employing three titrimetric methods and it was found to be at pH 7.98. The relationship between the adsorption degree and pH value of brine below and above the PZC is discussed. It was found that at the pH of solution exceeds the PZC of the rock, the adsorption was 0.43 and 0.86mg/g of rock for the two surfactants. However, at pH values below PZC, the adsorption as high as 3.66 and 4.49mg/g for the two surfactants. The synthesized surfactants are found to be suitable for the EOR applications at pH values higher than the PZC of the rock sample.     

CO2 Mobility and CO2/Brine Interfacial Tension Reduction by Using a New Surfactant for EOR Applications

The synthesis and use in enhanced oil recovery applications of a novel CO₂-philic surfactant derived from maleic anhydride and 2-butyl-1-octanol is reported. The synthesis involved the esterification of maleic anhydride to produce diester followed by sulfonation of the esterified product. The esterification reaction parameters were optimized for the maximum yield of 98.4%. By employing a silica sulfuric acid catalyst, the reaction kinetics of esterification were also investigated. The activation energy was found to be 45.58 kJ/mol. The sulfonation reaction of the esterified product was performed by using sodium bisulfite, and a yield of 82% of surfactant was achieved. The synthesized surfactant lowered the interfacial tension between CO₂/brine to 3.1 mN/m and effectively reduced the CO₂ mobility. This surfactant has a great potential to be used for CO₂ mobility control for CO₂?EOR applications.      

Synthesis of a New CO2 Philic Surfactant for Enhanced Oil Recovery Applications

The synthesis of CO₂ philic surfactant using maleic anhydride and 4-tert-butylbenzyl alcohol is reported. We reacted maleic anhydride with 4-tert-butylbenzyl alcohol to form bis(4-(tert-butyl)benzyl) fumarate and sulfonated the produced diester. The esterification reaction was optimized for a maximum yield of 98% of bis(4-(tert-butyl)benzyl) fumarate. First-order reaction kinetics with respect to acid was observed. The activation energy was found to be 55.62 kJ/mol. The sulfonated product of diester was obtained by the sulfonation reaction and the yield of 82% of surfactant was achieved. The in-house developed surfactant effectively lowered down the IFT between CO_2/brine to 4.2 mN/m. This surfactant is targeted for CO₂-EOR applications.     

A facile synthesis of 2-oxo-cyclopentenylphosphonates by carbonylation of zirconacyclopentenylphosphonate with oxalyl chloride

Addition of oxalyl chloride to zirconacycles prepared from 1-alkynylphosphonates 1 zirconocene dichloride, and two equivalents of EtMgBr smoothly produced novel 2-oxo-cyclopentenylphosphonates 6 in 58–81% isolated yields in the presence of a copper catalyst.     

Platinum and Palladium Complexes Bearing New (1R,2R)‐(–)‐1,2‐Diaminocyclohexane (DACH)‐Based Nitrogen Ligands: Evaluation of the Complexes Against L1210 Leukemia

The reaction of (1R,2R)‐(–)‐1,2‐diaminocyclohexane ( 1 ) [DACH] with the aldehyde (1R)‐(–)‐myrtenal ( 2 ) in MeOH afforded the bidentate diimine ligand, (1R,2R)‐(–)‐N¹,N²‐bis{(1R)‐(–)myrtenylidene}‐1,2‐diaminocyclohexane ( 3 ) in a high yield. Reduction of 3 using LiAlH₄ led to the formation of the desired ligand ( 4 ) (1R,2R)‐(–)‐N¹,N²‐bis{(1R)‐(–)myrtenyl}‐1,2‐diaminocyclohexane. Treatment of compound 4 with K₂PtCl₄ or K₂PdCl₄ yielded the corresponding platinum(II) and palladium(II) complexes, Pt‐5 and Pd‐6 , respectively. The reaction of compound 3 with K₂PtCl₄ gave the diimine complex Pt‐7 . The cytotoxic activity of the complexes Pt‐5 , Pd‐6 and Pt‐7 was tested and compared to the approved drugs, cisplatin ( Cis ‐Pt ) and oxaliplatin ( Ox‐Pt ). The complexes ( Pt‐5 , Pd‐6 and Pt‐7 ) inhibit L1210 cell line proliferation with an IC₅₀ of 0.6, 4.2, and 0.7 μL, respectively as evidenced by measuring thymidine incorporation.     

Synthesis of 3-hydroxy-1-alkenylboronates via phosphine stabilized borylzirconacyclopropenes

Zirconacyclopropenylboronates can be stabilized to dimerization by complexation with tributylphosphine; the phosphine stabilized zirconacycle boronates react with aliphatic and aromatic ketones and aldehydes at C2 of the triple bond to give the previously unknown 3-hydroxyvinylboronates in 61-80% isolated yields.     

Evaluation of phenolic contents and antioxidant activity of various solvent extracts of <Emphasis Type="Italic">Sonchus asper</Emphasis> (L.) Hill

Background  

Sonchus asper (SA) is traditionally used for the treatment of various ailments associated with liver, lungs and kidneys. This study was aimed to investigate the therapeutic potential of nonpolar (hexane, SAHE; ethyl acetate, SAEE and chloroform, SACE) and polar (methanol, SAME) crude extracts of the whole plant.     

FINITE PERMUTATION REPRESENTATION OF A SUBGROUP OF PICARD GROUP＊

We investigate action of a subgroup G1 of the Picard group on finite sets using coset diagrams.We show that its actions on the sets of 3,4,5,6,8,and 12 elements yield building blocks of Coset diagrams ...