Operations of online advertising services and publisher's option

We analyse the use of options for online advertisement publishers. By providing a discount or rewards to advertisers, publishers can utilise their uncertain service capacity, page-views, more efficiently. We use Generalised Nash Bargaining to study the feasibility of the option contract and solve for an optimal value for the option price. We compare the revenues and benefits from advertisements under the option contract, with those without the options using numerical studies. We also study the impact of pricing and other components in the game on the optimal option price, the publisher's revenues, and the advertiser's benefits from the advertisements.     

FUNCTIONALIZED PHOSPHINES: SYNTHESIS,REACTIVITY AND TRANSITION METAL CHEMISTRY

Ten-membered heterocycles of the type PhN(PCl₂){OC₆H₂(R)₂ (μ-S(CH₂))((R)₂─C₆H₂O─)} (R = Me, ⁱPr or ^tBu) have been prepared and their transition metal chemistry is explored. Functionalised phosphines react with transition metals to give interesting metallacycles. Several Group 6, ruthenium, platinum metals and novel titanium(IV) metallacycles have been structurally characterized.     

Synthesis,Structures, and Fungitoxicity of Novel Organophosphorus Compounds

Abstract

A series of biologically active organophosphorus compounds have been synthesized by the reactions of O,O-diethylchlorophosphate with Schiff bases derived from 5-(phenyl/substituted phenyl)-2-hydrazino-1,3,4-oxadiazole and salicylaldehyde/2-hydroxyacetophenone. The compounds have been characterized on the basis of analyses and spectral (IR, ¹H, ¹³C NMR) data. Fungicidal activities of these derivatives against Colletotrichum falcatum, Fusarium oxysporum, and Curvularia pallescence have been evaluated. All compounds showed moderate to significant antifungal activity.     

Characterization of a Polymer-Bound Palladium Acetate Catalyst and Studies on the Selective Hydrogenation of Dienes and Alkynes

Abstract

Palladium(II) acetate has been anchored onto a copolymer support containing pyridyl and carboxyl groups. XPS studies showed the Pd 3d binding energies for the recovered catalyst to be less by 1 eV after being used in hydrogenation studies. However, x-ray studies and a chemical test based on KCN treatment failed to reveal any palladium oxide or palladium metal formation in the recovered catalyst. It is presumed that an acetate ligand is lost during hydrogenation, which could be the reason for the lowering of the palladium 3d binding energies in the recovered catalyst. Results of investigations of the hydrogenation of olefins and selectivity of the catalyst toward the hydrogenation of dienes and alkynes are presented. The loss of palladium due to leaching under the reaction conditions employed was found to be very low (<1%/cycle).     

One-Step Hydroxylation of Benzene to Phenol Over Layered Double Hydroxides and their Derived Forms

Phenol, an important bulk organic compound, has diverse applications encompassing both industry and society. Commercially, it is produced through energy intensive three-step cumene process operating at relatively low yield with the co-production of acetone. Several attempts were made for producing phenol through challenging one-step direct hydroxylation of benzene using different oxidants like O₂, N₂O and H₂O₂. Liquid phase hydroxylation of benzene using H₂O₂ found to be more attractive due to its low reaction temperature and environmentally friendly nature (as water is only formed as by-product). The hydroxylation reaction occurs through Fenton’s mechanism; however along with phenol several other products are also formed due to higher reactivity of phenol compared to benzene. Our research group has been working on this reaction for nearly a decade using layered double hydroxides (LDHs) and their derived forms as heterogeneous selective oxidation catalyst. Screening of different LDHs having different metal ions in the layers revealed the necessity of copper for hydroxylation in pyridine. Addition of co-bivalent metal ion along with copper was made in an endeavour to improve the activity that revealed the promising results for CuZnAl LDHs. Efforts were then made to shift from pyridine to environmentally benign solvent, water, for this reaction that showed reasonably good yields with very high selectivity of phenol. Addition of small amount of sulfolane as a co-solvent increased the selectivity for phenol further. The reusability difficulty faced while using as-synthesized LDHs was overcome when calcined LDHs were used. Structure–property-activity relationships were deduced to understand the results observed. The present review besides covering our work also provides the state-of-art on this reaction using different oxidants with emphasis on H₂O₂.     

Iron(III) Chloride–Promoted Direct Conversion of Aryl/Alkyl Cyanides to Esters

Aryl/alkyl cyanides were quickly converted into the corresponding esters in the presence of iron(III) chloride in refluxing alcohols with very good yields.     

Separation and recovery of ruthenium: a review

The chemistry of the noble metal fission product, ruthenium is very complex due to the existence of many oxidation states in addition to forming a large number of co-ordination complexes. In the PUREX process for the separation of U and Pu from the spent nuclear fuels from fast breeder reactors, owing to the high volatile nature of RuO₄ problems arise not only during the extraction stages but also in the treatment of high active liquid waste and subsequent vitrification. As this volatile RuO₄ can deposit in cooler parts, there is an increase in the radiation field due to the presence of ¹⁰⁶Ru. The problem is very acute in the reprocessing of fast reactor fuels due to the increased concentration of ruthenium in the spent fuel. In nitric acid medium Ru can exist in various nitroso nitrate complexes and nitroso complexes are more stable than nitrates. The nitrates are non-extractable by the solvent TBP; however, they are extractable to a higher degree by DBP (the primary degradation product of TBP). The extractability of Ru nitrates into the solvent is inhibited by high acid content, temperature and prolonged hold-up time. Nevertheless, these factors promote the volatilization of Ru as RuO₄. The volatilization is enhanced by the addition of phosphate ions, but is suppressed by phosphite or hypophosphite ions. Thus, it would be advantageous if ruthenium is removed so that not only the purity of the product (Pu) is improved, but also the problem related to volatilisation can be resolved. High molecular weight amines (tertiary amines) capable of forming co-ordinate bonds are reported to be ideal extractants for Ru. Gas phase separation is an effective method for the recovery of Ru from catalysts, lead button and from other platinum group metals. Separation and pre-concentration of noble metals can be accomplished from non-metals by simple sorbents like coconut shell activated carbon to complicated chelating resins, aromatic polymers and zeolites. In the electro-oxidation of active Ru from nitroso salts, Pd was found to interfere and removal of Pd prior to oxidation of Ru is recommended. Redox catalysts such as Ag²⁺ and Ce⁴⁺ are found to play a prominent role in the electro-oxidation of Ru. Though, various methods and extractants are reported in the literature for the separation of Ru, R&D is being pursued for the removal of Ru during aqueous reprocessing of spent fuels using extractants and methods which are conducive to plant conditions. Hence, an exhaustive survey of literature was made and the different methods reported for the removal of Ru with emphasis towards reprocessing applications are discussed in this report as a review. Attempts made by the authors in separating Ru from simulated waste solution are also included in this review.     

Tuning the physical properties of a nematic liquid crystal elastomer actuator

In this report we demonstrate the ability to tune the physical properties of a liquid crystal elastomer (LCE) by varying the amount and type of crosslinking within the elastomer network. LCE films composed of a single mesogenic compound were capable of uniaxial contraction when thermally actuated through the nematic to isotropic phase of the material. We probed the physical properties of the LCE films while varying the amount and concentration of two crosslinking agents and measured actuation strains of 10–35%, elastic moduli of 3–14 MPa, and transition temperatures ranging between 75 and 60°C. The viscous losses of the elastomers and the estimated work capable of being produced by the films were also evaluated. The ability to tune the physical properties of the LCE films allows for a wide range of applications including robotics, microelectromechanical systems (MEMS), shape‐changing membranes, and/or microfluidics.