VOLUME 41, NO5, OCT-2019
12
 
Effect of Silicon Contents on Different Oxidizers Used in Delay Composition

Azizullah Khan, Abdul Qadeer Malik and Zulfiqar H. Lodhi

Study was undertaken on the mass consumption and burning time of ranges of Si/Pb3O4/FG and Si/PbO/FG pyrotechnic delay compositions by varying Silicon Content. Silicon is a fuel; PbO and Pb3O4 are oxidizers whereas Fish Glue is a binder. The mass consumption and burning time of both these compositions was determined with different silicon contents. The Silicon content was varied from 5 wt% to 55 wt% for Si/Pb3O4/FG delay mixture, whereas for Si/PbO/FG delay composition the Silicon content was varied from 5 wt% to 40 wt%. The mass consumption of Si/Pb3O4/FG composition increases and burning time decreases with increase in fuel content until the maximum mass consumption of 1.080 mg/ms and minimum burning time of 300 ms were recorded at 35 wt. % Silicon Content. Similarly, the mass consumption of Si/PbO/FG delay composition also increases and burning time decreases with increase in Silicon content buy beyond 15 wt% Silicon content the delay mixture shows unpredictable burning propagation behavior. Study was also conducted on the effect of fast red lead delay mixture as first fire charge to improve the burning performance of Si/PbO/FG delay compositions.
Pages(735)
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Process Optimization of Lycium ruthenicum Murr. Powder Preparation by Airflow Ultrafine Pulverization at Low Temperature and Characterization of its Antioxidant Activity

Deng Kai, Hu Na, Suo Yourui and Ding Chenxu

The processing of ultrafine pulverization Lycium ruthenicum Murr. by airflow is studied to determine the best parameters. Based on the single factor experiment, orthogonal experimental design is utilized to optimization of process parameters. The results show that the water content is 0.5%, air supply pressure is 0.70 Mpa,graded speed is 55 Hz, freezing time in the liquid nitrogen is 2 h. Under the condition of repeated trials, the average grading of L. ruthenicum fruit submicron powder is 19.8167 ± 0.53 μm. The contents of the total polysaccharides, anthocyanin and antioxidant activity in the water extract of submicron powders are obviously higher than the normal powder’s, which can efficiently increase the dissolution rate of active ingredients in L. ruthenicum Murr.
Pages(741)
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Enhanced UV Photo-Stabilization of Tyrosine with Benzotriazole Structure Formed Through Chemical Modification

Zongqian Wang, Yinchun Fang and Jun Li

In this paper, tyrosine was modified by the benzotriazole structure through the coupling reaction with the diazonium salt to form the intermediate and the ring-closing reaction of the intermediate to form the benzotriazole structure. Structure of intermediate and modified tyrosine was characterized via high performance liquid chromatography (HPLC), fourier transform infrared spectroscopy (FTIR), hydrogen nuclear magnetic resonance (1H-NMR) and mass spectra (MS) methods; then the photo-degradation curve under ultraviolet (UV) exposure of the modified tyrosine was measured and compared with the tyrosine; UV and fluorescence spectrum were used to analyze the photo-stabilization mechanism of the modified tyrosine. Results showed that the photo-degradation rate of modified tyrosine was less than one fifth of tyrosine after UV irradiation for 2 h and far less than that of tyrosine in the whole irradiation experiment in this work, proving that the photo-stability of the tyrosine was greatly improved by introducing the benzotriazole structure after the modification. From the analysis of UV and fluorescence spectrum, the photo-stabilization mechanism of the modified tyrosine was revealed.
Pages(750)
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Ru(III) Complexes of Phenoxy-İmine Ligands: Synthesis, Characterisation and Testing as Oxidation Catalysts

Ali Çapan, Gökhan Ceyhan and Mehmet Sönmez

A series of new mononuclear Ru(III) complexes bearing phenoxy-imine Schiff base tetradentate ligands (phenylimino, 4-chlore phenylimino, 3,4-dichlore phenylimino) have been prepared and characterized by elemental analysis, TGA, UV-VIS, FT-IR, 1H-NMR and 13C NMR spectra. The proposed structure of the ligands have a O2N2 core to form mononuclear Ru (III) complexes. Preliminary studies on the catalytic performances of the compounds in the cycloalkane oxydation are described. The catalytic effect of all Ru complexes results in the epoxidation reaction of cyclohexane, as shown in the substrate conversion reaction appears to be very high.
Pages(758)
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A Density Functional Theory Study of 3,5-dichlorosalicyliden-p-iminoacetophenone oxime Complexes with Co, Ni, Cu and Zn Metals

Ali Çapan, Erdal Canpolat, Henar Sleman and Niyazi Bulut

In this work, new Schiff baz ligand was synthesized by reaction of p-iminoacetophenone oxime with 3,5-dichlorosalicylaldehyde. Metal complexes of Co+2, Ni+2, Cu+2 and Zn+2 acetate metal salts were synthesized with this ligand. The ligand and complexes are characterized in experimental by their elemental analyses, X-ray, 1H-NMR, 13C-NMR, UV-Vis, FT-IR, magnetic susceptibility and thermogravimetric analyses (TGA) and also have been investigated by using quantum mechanical methods. The transition metals are coordinated to the schiff base through the azomethine nitrogen and the carboxyl oxygen atom. Obtained metal complexes were studied the magnetic properties and their geometries were determined. Co+2, Ni+2 and Zn+2 complexes have been found tetrahedral geometry and Cu+2 complex has been found four coordinated geometry.
Pages(770)
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Pyrolysis of Polystyrene: The Influence of Commercially Available Oxides as Catalysts

Jan Nisar, Muhammad Sufaid Khan, Ghulam Ali, Afzal Shah, Rafaqat Ali Khan, Faheem Shah, Sirajuddin, Syed Tufail Hussain Sherazi and Munawar Iqbal

In this study four catalysts (ƴ –Alumina, α- Alumina, silica gel and silica ppt) with different physicochemical characteristics were tested for the pyrolysis of polystyrene (PS) under inert atmosphere in the temperature range 200-650 °C at heating rate 5 °C/min. The silica gel a mesoporous catalyst, with a greater pore size and surface area was found to be the most active materials in terms of reduction in maximum temperature. The ƴ –Alumina catalyst also shows good result because of the acidic sites, surface area, and pores size, however, its degradation effect is less than silica gel. The effect of α- Alumina catalyst on the pyrolysis of PS is less pronounced due to its small surface area, pore size and lack of acidic sites on its surface. The effects of these catalysts show that surface area, number of acidic sites and pore size were observed as the key factors for effective degradation of polymers.
Pages(779)
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Investigating the Impact of Hard Water on Natural Dyeing of Cotton Fabric by Tagetes erecta Flowers

Iqra Khalid, Shaukat Ali, Muhammad Tahir Hussain, Rizwan Ashra, Asfandyar Khan and Naseer Ahmad

Ground water is commonly used media for most of textile processing treatments and it is often inherent with significant degree of hardness. This study is undertaken to evaluate the influence of water hardness on dyeing of cotton fabric by natural colorant extracted from flowers of Tagetes erecta. Response Surface Methodology (RSM) was applied for optimization of extraction and application of the natural colorant. Results were examined by Analysis of variance (ANOVA). In the present study, effect of process parameters viz. time (30–90 min), temperature (60–90oC) and concentration of hard water (250–1250 ppm) on natural dyeing process (K/S value) were modelled by employing RSM based central composite design. For the applications of natural colorants, mordanting technique was employed wherein the results of pre-mordanting and post-mordanting were studied comparatively. The dyed fabric was evaluated for colour strength (K/S) and CIELab values. It was observed that increase in water hardness adversely influenced the colour strength and it also adds to significant degree of unevenness in cotton dyeing using natural colorant.
Pages(788)
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Effect of MgO Addition on the Properties of Ni/Al2O3 and Its Catalytic Activity in Hydrogenation of N-(2`,3`-dimethoxy benzyl)-3,4-dioxy-methylene-phenylethylamine

Guosheng Wang, Xinxin Zhao and Siyu Han

the nickel based alumina-supported catalysts modified or promoted by magnesia were prepared by wet impregnation and successfully used for hydrogenation of N-(2`,3`-dimethoxy benzyl)-3,4-dioxy-methylene-phenylethylamine, the 20Ni-6MgO/74Al2O3 samples exhibits the highest BET surface area, the largest pore volume, and the largest pore diameter in all of the samples such as Ni/Al2O3 and 20Ni-xMgO(80-x)Al2O3 excepted the highest BET surface area of Ni/Al2O3. the average pore diameter of the 20Ni-6MgO/74Al2O3 samples were two times as large as Ni/Al2O3, it was indicated that the function of expanding role or the mesoporosity was increased by addition of MgO, and MgO might be regarded as pore-enlarge agent for the bare Al2O3 support and benefit for the transport of large molecules reactants and products The weak formation of MgO-Al2O3 and MgO-NiO solid solution as a result of competing interaction of MgO with Al2O3 support and NiO precursors restrained the strong interaction of NiO species with Al2O3 support, which favored the dispersion of active Ni centers and improved the reducible degree of NiO species on the surface of the catalysts. The improvement of basicity or the decrease in the number of acid centers in the catalysts avoid the secondary reactions, and subsequently resulted in high catalytic activity. The utilization of meso-porous 20Ni-6MgO/74Al2O3 for catalytic hydrogenation of N-(2`,3`-dimethoxy benzyl)-3,4-dioxy-methylene-phenylethylamine(Shiff’s base) with the highest selectivity of 99.70% and yields of 94.36% implied that the instead of Raney Ni was feasible.
Pages(796)
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A Green and Sustainable Approach for Acetalization of Benzaldehyde Using Tungstophosphoric Acid Loaded on Metal Oxide Catalysts

Li Fanghao, Li Chenjie, Chen Junyi, Wang Kuiwu, Zhang Haijiang, Wang Yanbo and Han Xiaoxiang

A series of tungstophosphoric acid (H3PW12O40; HPW) loaded on metal oxide catalysts, namely H3PW12O40/M (M= TiO2, CeO2, ZrO2) was prepared by initial wetting impregnation method and their catalytic performances were also investigated during the condensation reaction of benzaldehyde with glycol. Among them, the 20 wt% H3PW12O40/TiO2 catalyst demonstrated highly active with superior acetal yield (90.1 %) and excellent durability. The high activity of the catalyst derived from high surface area, ultra-strong Brønsted acidity and synergetic effect of Brønsted-Lewis acid. Response surface methodology (RSM) based on Box-Behnken design (BBD) was used to optimize the course of the condensation reaction of benzaldehyde with glycol, and the optimal benzaldehyde glycol acetal yield (93.4 %) could be obtained. The optimized yield and the experimental results are similar. Moreover, under optimal reaction conditions, the activation energy (Ea) of reaction could be obtained through the kinetic study of the irreversible parallel reaction model, and the Ea was 23.24 kJ/mol.
Pages(805)
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Mass Transfer Enhancement for CO2 Absorption in Structured Packed Absorption Column

Pongayi Ponnusamy Selvi and Rajoo Baskar

The acidic gas, Carbon dioxide (CO2) absorption in aqueous ammonia solvent was carried as an example for industrial gaseous treatment. The packed column was provided with a novel structured BX-DX packing material. The overall mass transfer coefficient was calculated from the absorption efficiency of the various runs. Due to the high solubility of CO2, mass transfer was shown to be mainly controlled by gas side transfer rates. The effects of different operating parameters on KGav including CO2 partial pressure, total gas flow rates, volume flow rate of aqueous ammonia solution, aqueous ammonia concentration, and reaction temperature were investigated. For a particular system and operating conditions structured packing provides higher mass transfer coefficient than that of commercial random packing.
Pages(820)
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