Novel long chain unsaturated diisocyanate from fatty acid: Synthesis,characterization, and application in bio‐based polyurethane

A novel long chain linear unsaturated terminal diisocyanate, 1,16‐diisocyanatohexadec‐8‐ene (HDEDI) was synthesized from oleic acid via Curtius rearrangement. Its chemical structure was identified by FTIR, ¹H NMR, ¹³C NMR, and HRMS. This diisocyanate was used as a starting material for the preparation of entirely bio‐based polyurethanes (PUs) by reacting it with canola diol and canola polyol, respectively. The physical properties and crystalline structure of the PUs prepared from this diisocyanate were compared to their counterparts prepared from similar fatty acid‐derived diisocyanate, 1,7‐heptamethylene diisocyanate (HPMDI). The HDEDI based PUs demonstrated various different properties compared to those of HPMDI based PUs. For example, HDEDI based PUs exhibited a triclinic crystal form; whereas HPMDI based PUs exhibited a hexagonal crystal lattice. In addition, canola polyol‐HDEDI PU demonstrated a higher tensile strength at break than that of canola polyol‐HPMDI, attributed to the higher degree of hydrogen bonding associated with the former sample. Nevertheless, lower Young's modulus and higher elongation in canola polyol‐HDEDI PU were obtained because of the flexibility of the long chain introduced by the HDEDI diisocyanate. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3302–3310, 2010     

Aziridination of 3-methyl-4-nitro-5-styrylisoxazoles

Herein we describe the preparation of a novel class of isoxazolyl aziridines. The products were obtained exclusively as cis diastereoisomers.     

Learning and forgetting effects on a group scheduling problem

This paper proposes to investigate learning and forgetting effects on the problem of scheduling families of jobs on a single machine to minimize total completion time of jobs. A setup time is incurred whenever the single machine transfers job processing from a family to another family. To analyze the impact of learning and forgetting on this group scheduling problem, we structure three basic models and make some comparisons through computational experiments. The three models, including no forgetting, total forgetting and partial forgetting, assume that the processing time of a job is dependent on its position in a schedule. Some scheduling rules and a lower bound are derived in order to constitute our branch-and-bound algorithm for searching an optimal sequence. In addition, an efficient and simply-structured heuristic is also built to find a near-optimal schedule.     

Rotational analysis of 3664 Å band of NiCl

Nickel chloride was excited in a high frequency discharge source and the band at 3664 Å was photographed at an inverse dispersion of 0.59 Å/mm on a two metre plane grating spectrograph. The rotational analysis was carried out and the molecular constants of the upper state are reported. The rotational isotopic shifts due to³⁷Cl support the rotational analysis. The electronic transition involved is identified to beβ ²Δ_5/2 →X ₁ ²Δ_5/2.     

Inference on superimposed subcritical Galton-Watson processes with immigration

Summary In this paper we consider the superimposed processZ generated by two independent subcritical Galton-Watson processesX ₁ andX ₂, with immigration, by the relationZ=X ₁ +X ₂. The seemingly second order autoregressive relation, that is identified inZ, is exploted towards proposing CAN estimators for the parameters ofZ,X ₁ andX ₂, based on only a partial realisation ofZ, using time series techniques. The results of this paper are motivated by a time series approach for studying specific branching processes due to Venkataraman (1982,Adv. Appl. Prob.,14, 1–20).     

Ditolyldithiophosphato derivatives of phosphorus(III) and phosphorus(V)

O,O′-Ditolylphosphorodithioates of phosphorus(III), [(o-, m-, or p-CH₃C₆H₄O)₂PS₂] _n PCl_3−n , and phosphorus(V), [(o-, m-, or p-CH₃C₆H₄O)₂-PS₂] _n POCl_3−n , (n = 1, 2, and 3) were isolated as colorless viscous liquids by the reaction of PCl₃ and POCl₃ with sodium ditolylphosphorodithioate, (o-, m-, or p-CH₃C₆H₄O)₂PS₂Na, in 1:1, 1:2, and 1:3 molar ratios in toluene. These compounds were characterized by elemental analyses, molecular weight measurements, IR, and NMR (¹H, ³¹P, and ¹³C) spectroscopic studies, which indicated a less common monodentate linkage of dithiophosphate moieties in both phosphorus(III) and phosphorus(V) derivatives leading to a tetrahedral geometry around the phosphorus atom.     

Phosphosulfonic acid‐catalyzed green synthesis and bioassay of α‐aryl‐α′‐1,3,4‐thiadiazolyl aminophosphonates

A series of new α‐aminophosphonates containing 1,3,4‐thiadiazole moiety (4a–l) were synthesized via a simple, efficient, and one‐pot three‐component Kabachnik–Fields reaction of 2‐amino‐5‐ethyl‐1,3,4‐thiadiazole with various aryl/heteroaryl aldehydes and diethylphosphite under solvent‐free microwave irradiation conditions using phosphosulfonic acid, as a reusable and heterogeneous solid acid catalyst. All the title compounds were screened for radical scavenging activity by DPPH and H₂O₂ methods, and antimicrobial activity against bacteria (Gram‐positive and Gram‐negative) and fungi using the disc diffusion technique. They exhibited potent in vitro antioxidant and moderate antimicrobial activity.