Magnetite nanoparticle mediated catalytic aquathermolysis of Omani heavy crude oil

The worldwide demand for energy continues to grow and the production of heavy crude is escalating due to shortage of conventional light crude. The transportation of heavy crude oil from the head-well to the refinery is a challenging task due to its high viscosity and low API gravity. Catalytic aquathermolysis is one of the most significant and cost-effective viscosity reduction techniques employed in the up gradation of the crude oil at elevated temperatures and hence to enhance oil extraction process. In this study, catalytic aquathermolysis of Omani heavy crude oil was performed using magnetite nanoparticles (NPs). The NPs were synthesised by reverse co-precipitation method using iron salts in alkaline medium. The synthesised NPs were characterized using Scanning Electron Microscopy (SEM), X-Ray Powder Diffraction (XRD), Energy Dispersive X- Ray analysis (EDX) and Fourier Transform Infrared Spectroscopy (FTIR). The XRD results exhibited a characteristic peak confirming the high purity of iron oxide nanoparticles. The FTIR spectral analysis designated two well-defined peaks corresponding to wave numbers of 500 ?cm^?1 and 630 ?cm^?1, endorses the presence of Fe–O. The catalytic aquathermolysis experiments were carried out in a Parr high temperature-high pressure batch reactor at different experimental conditions. The processing parameters in temperature range of 250 ?°C - 300 ?°C, 0.1% to 0.3% catalyst loading, water to oil ratio of 1:7 to 3:7 with 24–72 ?h of reaction time. The initial pressure in the reactor was maintained at 32 ?bars and the optimization was performed using the Taguchi method to maximize the level of heavy oil. An orthogonal array was employed to analyse the effects of mean response and mean signal-to-noise ratio (S/N) to upgrade the heavy oil. The regression analysis was used to establish a relationship between the viscosity and experimental parameters. The experimental outcomes indicates that the maximum reduction in viscosity occurred at a processing temperature of 300 ?°C, 1:7 ?W/O ratio, 0.1 ?wt% of catalyst concentration and 48 ?h of reaction time. Similarly, the optimum conditions for the reduction in API gravity were obtained at 280 ?°C temperature, 3:7 ?W/O ratio, 0.2 ?wt% of catalyst concentration and a reaction time of 24 ?h.     

Acute and sub-acute toxicity study of hydroalcoholic fruit extract of Pithecellobium dulce

This study was carried out to evaluate the acute and sub-acute toxicity profile of the hydroalcoholic fruit extract (HAEPD) of Pithecellobium dulce (Leguminosae). Albino rats were treated orally with 100, 200 and 500?mg?kg(-1) bodyweight (BW) of HAEPD for 90 days to assess its sub-acute toxicity. HAEPD at single doses of 100, 500, 1000, 2000 and 4000?mg?kg(-1) BW was also administered to rats to assess its acute toxicity. The rats were observed for physical discomfort, BW change and feeding habits. Pithecellobium dulce did not cause any abnormal changes in haematological or biochemical parameters. Pathologically, no gross abnormality in the tissue architecture was observed. The LD(50) was found to be 3916?mg?kg(-1) BW and potential effective doses for efficacy studies are 100 and 300?mg?kg(-1) BW as the minimum and maximum doses, respectively. It is concluded that HAEPD can be used safely for experimental and clinical trials.     

Magnetic nanoparticle‐tethered Schiff base–palladium(II): Highly active and reusable heterogeneous catalyst for Suzuki–Miyaura cross‐coupling and reduction of nitroarenes in aqueous medium at room temperature

As a continuation of our efforts to develop new heterogeneous nanomagnetic catalysts for greener reactions, we identified a Schiff base–palladium(II) complex anchored on magnetic nanoparticles (SB‐Pd@MNPs) as a highly active nanomagnetic catalyst for Suzuki–Miyaura cross‐coupling reactions between phenylboronic acid and aryl halides and for the reduction of nitroarenes using sodium borohydride in an aqueous medium at room temperature. The SB‐Pd@MNPs nanomagnetic catalyst shows notable advantages such as simplicity of operation, excellent yields, short reaction times, heterogeneous nature, easy magnetic work up and recyclability. Characterization of the synthesized SB‐Pd@MNPs nanomagnetic catalyst was performed with various physicochemical methods such as attenuated total reflectance infrared spectroscopy, UV–visible spectroscopy, inductively coupled plasma atomic emission spectroscopy, energy‐dispersive X‐ray spectroscopy, field‐emission scanning electron microscopy, transmission electron microscopy, powder X‐ray powder diffraction, thermogravimetric analysis and Brunauer–Emmett–Teller surface area analysis.     

Analysis of the hot bands in the 2ν9 band region of propyne-d3

The rovibrational spectrum of 2ν₉ band of CD₃CCH is overlapped by two prominent hot bands identified as (2ν₉⁰+ν₁₀^±1)(E)←ν₁₀^±1(E) and 3ν₉^±1(E)←ν₉^±1(E), where ν₁₀ and ν₉ are the degenerate CCC and CCH bending fundamental vibrations, respectively. Assignment of lines to the transitions of these hot bands were carried out with the help of the high-resolution spectra recorded at ∼195 K and at room temperature. Molecular parameters for these hot bands have been obtained from the rotational analysis of the partially resolved K-structure lines. Only Q-head of the third hot band , originating from the lower 2ν₁₀ state could be identified.     

Time-Cost Trade-Off Analysis in Some Constrained Assignment Problems

Several variations of two-dimensional (workers x jobs) and three-dimensional (workers x jobs x machines) time- as well as cost-minimizing assignment problems, which arise owing to (i) precedence relations of some form among the jobs or (ii) capacity restrictions on workers/machines imposed by the requirement that the surplus resources have to be fully employed, have been considered in the literature. In this paper, an algorithm is presented for time-cost trade-off analysis which is applicable to any general pair of such constrained problems. The algorithm is also illustrated by a numerical example.     

Pulsed photoacoustic technique to study nonlinear processes in liquids: Results in toluene

Pulsed photoacoustic measurements have been carried out in toluene at 532 nm wavelength using a Q-switched frequency doubled Nd:YAG laser. The variation of photoacoustic signal amplitude with incident laser power indicates that at lower laser powers one photon absorption takes place at this wavelength while a clear two photon absorption occurs in this liquid at higher laser powers. The studies made here demonstrate that pulsed photoacoustic technique is simple and effective for the investigation of multiphoton processes in liquids.     

Ionic Liquid‐Based Routes to Conversion or Reuse of Recycled Ammonium Perchlorate

New, potentially green, and efficient synthetic routes for the remediation and/or re‐use of perchlorate‐based energetic materials have been developed. Four simple organic imidazolium‐ and phosphonium‐based perchlorate salts/ionic liquids have been synthesized by simple, inexpensive, and nonhazardous methods, using ammonium perchlorate as the perchlorate source. By appropriate choice of the cation, perchlorate can be incorporated into an ionic liquid which serves as its own electrolyte for the electrochemical reduction of the perchlorate anion, allowing for the regeneration of the chloride‐based parent ionic liquid. The electrochemical degradation of the hazardous perchlorate ion and its conversion to harmless chloride during electrolysis was studied using IR and ³⁵Cl NMR spectroscopies.     

From small structural modifications to adjustment of structurally dependent properties: 1‐methyl‐3,5‐bis[(E)‐2‐thienylidene]‐4‐piperidone and 3,5‐bis[(E)‐5‐bromo‐2‐thienylidene]‐1‐methyl‐4‐piperidone

The molecules of the title compounds, C₁₆H₁₅NOS₂, (I), and C₁₆H₁₃Br₂NOS₂, (II), are E,E‐isomers and consist of an extensive conjugated system, which determines their molecular geometries. Compound (I) crystallizes in the monoclinic space group P2₁/c. It has one thiophene ring disordered over two positions, with a minor component contribution of 0.100 (3). Compound (II) crystallizes in the noncentrosymmetric orthorhombic space group Pca2₁ with two independent molecules in the unit cell. These molecules are related by a noncrystallographic pseudo‐inversion center and possess very similar geometries. The crystal packings of (I) and (II) have a topologically common structural motif, viz. stacks along the b axis, in which the molecules are bound by weak C—H...O hydrogen bonds. The noncentrosymmetric packing of (II) is governed by attractive intermolecular Br...Br and Br...N interactions, which are also responsible for the very high density of (II) (1.861 Mg m⁻³).     

Determination of concentration of iodine in grass and cow milk by NAA methods using reactor neutrons

Instrumental and preconcentration methods of neutron activation analysis (NAA) have been standardized for the determination of concentration of iodine in grass and cow milk samples, respectively. To study the transfer of iodine from grass to milk, known quantity of grass spiked with potassium iodide solution was fed to a cow. The spiked grass samples and milk samples, obtained from the cow after the ingestion of spiked grass, were collected. Iodine was separated from the milk samples chemically using Dowex 1X8 anion exchange resin. Spiked grass and ion exchange resin samples were neutron irradiated and radioactive assay was carried out using a 45?% relative efficiency HPGe detector coupled to an 8k channel analyzer. Iodine concentrations in spiked grass samples were found to be in the range of 1,487?C2,002?mg?kg^?1. Concentration of iodine in milk after 12?h of feeding the cow with spiked grass was 871?±?56???g?L^?1 which was reduced to 334?±?32???g?L^?1 after 48?h.