Showing papers by "Umer Rashid published in 2016"
TL;DR: In this paper, the authors analyzed the effects of soxhlet process parameters (temperature, solvent to seed ratio and time) on the extraction of oils from waste Date pits and the subsequent production of biodiesel from it.
79 citations
TL;DR: In this paper, a polymeric mixed metal oxide with different (Al/(Zn + Al) molar ratio was initially synthesized as a parent mesoporous ZnAl2O4 material.
77 citations
TL;DR: Experimental analysis and predicted molecular properties supported the experimental analysis that these compounds have potential to eradicate both visceral and topical leishmaniasis.
75 citations
TL;DR: In this article, a heterogeneous solid acid catalyst was successfully developed from starch by a significant two-step process; the initial step was incomplete carbonization of starch at 400°C for 12h and consequently followed by sulfonation process using concentrated H 2 SO 4 to produce sulfonated-incomplete carbonized starch (ICS-SO 3 H).
75 citations
TL;DR: Sixteen 4-hydroxycoumarin derivatives were synthesized, characterized through EI-MS and (1)H NMR and screened for urease inhibitory potential and structure activity relationship was established on the basis of molecular docking studies, which helped to predict the binding interactions of the most active compounds.
54 citations
TL;DR: Bis-thiobarbiturate derivatives 1−15 have been synthesized, characterized by 1HNMR and EI-MS and screened for urease inhibition as mentioned in this paper.
53 citations
TL;DR: In this paper, the esterification of palm fatty acid distillate (PFAD) in supercritical methanol was investigated by using carbohydrate-derived solid acid catalyst The catalysts were prepared by sulfonation of incomplete carbonized glucose and starch.
53 citations
TL;DR: In silico ADMET predictions suggest that these compounds are non-AMES toxic with good blood brain barrier (BBB) penetration, human intestinal absorption and binding insights into the enzyme are well accommodated in the active site and interact with the key amino acid residues of Catalytic anionic site (CAS) and peripheral anionic sites (PAS).
48 citations
TL;DR: In this article, the production of pentaerythritol ester (PE) as food grade lubricant base oil was investigated and the properties of formulated lubricant (AWCI) and neopentyl glycol esters (NPGE) were tested.
37 citations
TL;DR: In this article, the authors used a pulsed loop reactor to transester the palm methyl ester (PME) and trimethylolpropane (TMP) to produce palm oil based TMP ester.
31 citations
TL;DR: In this paper, a mixture of cerium oxide and magnesium oxide supports with certain mole ratios of Mg2+/Ce3+ were prepared via the co-precipitation of mg and Ce nitrates, and followed by impregnation with 1 wt% each of Ni, Pd, and Pt metals to form Pt,Pd, Ni/Mg1−xCexO catalysts.
Abstract: A mixture of cerium oxide and magnesium oxide supports with certain mole ratios of Mg2+/Ce3+ were prepared via the co-precipitation of Mg and Ce nitrates, and followed by impregnation with 1 wt% each of Ni, Pd, and Pt metals to form Pt, Pd, Ni/Mg1−xCexO catalysts. Evaluation of the prepared catalysts was carried out by a DRM reaction for 200 h and they were characterised by means of in situ XRD, XRF, XPS, BET, H2-TPR, TEM and TGA. It was found that the interaction of a suitable amount of MgO with Ce2O3 stabilised a cubic phase in the catalysts, which has a high basicity to adsorb CO2 forming a monoclinic Ce2O2CO3 species in the DRM reaction. The introduction of MgO also created surface oxygen ions. The oxidisation and the removal of the deposited carbon maybe achieved by both monoclinic Ce2O2CO3 and surface oxygen, keeping the metal Ni, Pd, and Pt catalyst at high activity and stability. The Ce2O3 as a promoter in the catalyst had several effects such as: stabilisation of the magnesia cubic phase; increase in its thermal stability, increase in the basicity of the support, decrease in the carbon deposition, and decrease in the reducibility of the Ni2+, Pd2+, and Pt2+ ions.
TL;DR: In this paper, the potential of palm-based neopentyl glycol diester as dielectric insulating fluid was investigated and the thermal aging performance of NPG diester was compared with conventional mineral insulating oil at 90, 110 and 130 °C.
Abstract: The potential of palm-based neopentyl glycol diester as dielectric insulating fluid was investigated. The details of the transesterification of high oleic palm oil methyl ester (POME) with neopentyl glycol (NPG) with the final product yield of more than 90 wt% of NPG diester were discussed. The thermal aging performance of NPG diester was compared with conventional mineral insulating oil at 90, 110 and 130 °C. This paper focused mainly in the effects of aging to chemical, physical and electrical properties of NPG diester. Apart from being fully biodegradable and non-toxic, the synthesized diesters exhibited high flashpoint and the breakdown voltage was comparable to mineral oil. The result indicated that throughout the aging period, NPG diester exhibited lower acid value than mineral oil and no significant change in viscosity was observed. The study on mechanical properties of insulating paper aged in NPG diester shows higher tensile strength than paper aged in mineral oil. The synthesized esters have shown great potential to be used as transformer oil.
TL;DR: In this article, a series of diorganotin (IV) complexes of the Schiff base ligand derived from 7methoxy-2-hydroxy-1-naphthaldehyde, 1,2-phenylenediamine, Salicylaldehyde were synthesized.
Abstract: The search for an alternative to platinum anticancer agents is a major motivation for continuing investigations concerning the antitumor properties of other transition metal-based compounds. Keeping this in view, synthesis, antitumor and antimicrobial activity of diorganotin (IV) complexes was studied. A novel series of diorganotin (IV) complexes of the Schiff base ligand derived from 7-methoxy-2-hydroxy-1-naphthaldehyde, 1,2-phenylenediamine, Salicylaldehyde were synthesized. Physical and spectral examination was done through various techniques using elemental analyses, IR, 1H, 13C, 119Sn NMR, and 119mSn Mossbauer techniques respectively. The results obtained are in good agreement with 1:1:1 stoichiometry of Schiff base and 2:1 stoichiometry of the complexes. Octahedral geometry was assigned to all the synthesized complexes within six (6) coordination number around the tin. Antitumor activity was screened against human oral epidermoid carcinoma (KB) cell line. The diethyltin (IV) complex 2 showed the most promising cytotoxic results (IC50=0.35μM) against the cell line which is comparable with cisplatin (IC50=0.37μM). Docking studies revealed that these complexes can bind favorably within cisplatin binding site and the binding energy of complex 2 is more than that of cisplatin. Furthermore, binding of these complexes on human topoisomerase IIα enzyme and revealed that these complexes intercalating within the inter-strand of DNA showing interactions with DNA as well as protein that may results in DNA damage and cell death.
TL;DR: The results revealed that the introduction of benzyloxy (4a-e) and phenyl ethanone group at 4-position of dimethoxy benzyl ring leads to overall increase in the antibacterial activity.
TL;DR: This study focussed on selection of fast-growing microalgae with higher lipid content using cheaper growth media, aimed to reduce the cost of algal biomass production.
Abstract: The present study was focussed on selection of fast-growing microalgae with higher lipid content using cheaper growth media, aimed to reduce the cost of algal biomass production. Samples were collected from 40 different sites from fresh and wastewater bodies. Based on morphological differences, two microalgae (SSG and SA) from wastewater and three (OP, DFM and JRC) from fresh water habitat were selected for further characterization. The specific growth rates (g Day −1 L−1) of the OP, DFM, JRC, SA and SSG were found to be 0.614, 0.638, 0.734, 1.06 and 1.02, respectively, whereas the doubling time (Td) was shown to be as 39.30, 36.48, 22.08, 12.24 and 12.98 h, respectively, when cultured without controlled temperature and CO2 supply, in a locally designed photobioreactor. All five microalgae shown considerable growth at a range of pH 6.0–9.0 with a peak activity within pH range 7.5–8.5. The OP, DFM and JRC contained 27%, whereas SSG and SA shown 39% lipid content. The phylogenetic analyses based on ...
TL;DR: Combined in silico and in vitro studies shed insights into the mechanism of synthesis and antibacterial activity of 2-amino-1,4-dihydropyrimidines.
Abstract: In this study, we have investigated small multitargeted molecules containing 2-aminopyrimidine scaffold that may further act as precursor for developing more potent antibacterials. An efficient route to 2-amino-1,4-dihydropyrimidines by using ultrasound irradiation as the energy source was developed. In silico density functional theory calculations illustrated that tin chloride-mediated Biginelli reaction to produce 2-amino-1,4-dihydropyrimidines has energetics quite accessible under the reaction conditions. Calculated minimum inhibitory concentrations against the various bacterial strains showed that compounds 3 and 11 displayed comparable in vitro activity to ciprofloxacin in Staphylococcus aureus strains and reduced potency in Escherichia coli strains. Further, we investigated in silico ADMET profiling of synthesized compounds in order to understand the mechanism of action that help in explaining in vitro results. Lead compounds 3, 6, and 11 are predicted to have acceptable pharmacokinetic/drug-like properties. Data mining and computational analysis were employed to derive compound promiscuity phenomenon. All the compounds were found nonsubstrate towards various aminergic G-protein coupled receptors, ion-channels, kinase inhibitor, nuclear receptor ligand, protease inhibitor, and enzyme inhibitor. Compound 3 was further investigated by in silico binding to different antibacterial targets. Binding energy data revealed that that these compounds have the ability to bind with other bacterial targets. Hence, combined in silico and in vitro studies shed insights into the mechanism of synthesis and antibacterial activity of 2-amino-1,4-dihydropyrimidines. Results of this study are promising and can be used for further investigation by medicinal chemists to explore their chemical functionalization and in vivo studies.
TL;DR: In this article, a comparative study for the removal of health risk organic dye reactive blue 21 from aqueous solution using sorption and solubilization was performed, where activated carbon was used as sorbent to remove dye.
Abstract: This manuscript reports comparative study for the removal of health risk organic dye reactive blue 21 from aqueous solution using sorption and solubilization. Activated carbon was used as sorbent to remove dye. The bath sorption experiments were carried out at different pH, sorbent dosage, contact time, initial concentration, and agitation speed. The applicability of the Langmuir and Freundlich isotherm models was examined. The influence of cationic surfactant, cetyltrimethyl ammonium bromide (CTAB), and an anionic surfactant, sodium dodecyl sulfate (SDS) on spectral properties of selected dye in aqueous solutions was investigated by means of UV–Visible spectroscopy in sub-micellar and micellar concentration range. Absorption spectra of this dye in the presence of surfactants may confirm which type of interaction is possible between molecules of dye and surfactants. It is expected that initially molecules of dye may attach with monomeric molecules of surfactant in premicellar region while in post-micellar...
TL;DR: In this article, Fe-Mn doped sulphated zirconia catalyst was synthesized and used in simultaneous esterification and transesterification of waste cooking oil to biodiesel synthesis.
Abstract: Biodiesel of waste cooking oil origin is gaining attention as a replacement for current fossil fuels, as its low-priced, recycled feedstock shall prevent food source competition, which is estimated to happen with current biodiesel production processes. As a result, waste cooking oil has been claimed to be a highly potential feedstock for biodiesel production. In the present research work, Fe-Mn doped sulphated zirconia catalyst was synthesized and used in simultaneous esterification and transesterification of waste cooking oil to biodiesel synthesis. The catalyst was prepared through the impregnation method and characterized by using XRD, TPD-NH3, FT-IR, BET, and TEM. Response surface methodology (RSM) in conjunction with the central composite design (CCD) was applied to statistically evaluate and optimize the biodiesel preparation process. It was found that the synthesis of biodiesel achieved an optimum level of 97.2% waste cooking oil methyl ester’s (WCOME’s) yield at the following reaction cond...
TL;DR: In this article, a quadratic polynomial equation was determined using response surface methodology for predicting optimum methyl esters yield from Cannabis sativa oil from 30 to 90 min.
Abstract: The present study was appraised using response surface methodology for process optimization owing to strong interaction of reaction variables: NaOCH3 catalyst concentration (0.25–1.50%), methanol/oil molar ratio (3:1–9:1), reaction time (30–90 min), and reaction temperature (45–65°C). The quadratic polynomial equation was determined using response surface methodology for predicting optimum methyl esters yield from Cannabis sativa oil. The analysis of variance results indicated that molar ratio and reaction temperature were the key factors that appreciably influence the yield of Cannabis sativa oil methyl esters. The significant (p < 0.0001) variable interaction between molar ratio × catalyst concentration and reaction time × molar ratio was observed, which mostly affect the Cannabis sativa oil methyl esters yield. The optimum Cannabis sativa oil methyl esters yield, i.e., 86.01% was gained at 53°C reaction temperature, 7.5:1 methanol/oil molar ratio, 65 min reaction time, and 0.80% catalyst concen...
TL;DR: In this paper, an iron-manganese doped zirconia-supported molybdenum oxide catalyst has been prepared and used in the synthesis of waste cooking oil based biodiesel by a simultaneous esterification and transesterification method.
Abstract: Biodiesel derived from simultaneous esterification and transesterification of waste cooking oil has been attracting consideration as a replacement green fuel for diesel fuels, as it is economically feasible and circumvents the issue of energy versus food, which is estimated to take place with current biodiesel production techniques. In this optimization study, iron-manganese doped zirconia-supported molybdenum oxide catalyst has been prepared and used in the synthesis of waste cooking oil based biodiesel by a simultaneous esterification and transesterification method. The catalyst is prepared via an impregnation method and consequently characterized by XRD, TEM, TGA (thermogravimetric analysis), TPD-NH3, and Brunauer–Emmer–Teller (BET) techniques. The simultaneous process for biodiesel production has been assessed and improved statistically via response surface methodology in combination with the central composite design. It has been established that the process for synthesis of waste cooking oil based biodiesel achieved about 96.8% biodiesel yield at a best condition of 200 °C, waste cooking oil/ methanol molar ratio of 1:30 and 5.0 wt. % as loading of the catalyst. The highest ester yield of 96.8% has been obtained due to the improved physicochemical properties of zirconia-supported molybdenum oxide catalyst which accesses diffusion of the reactants to the active sites.
Journal Article•
TL;DR: In this paper, the effect of different pressures of sterilization on digestion operation was investigated and it was found that fruit sterilized at higher pressure released more oil into the condensate and absorbed more water.
Abstract: Sterilization and digestion are two important steps in the palm oil milling process prior to oil extraction. After sterilization, palm fruitlets are stripped and then fed into a digester where the fruitlets are heated with atmospheric pressure steam to soften and loosen the mesocarp fiber. The effect of different pressures of sterilization on digestion operation needs to be investigated. To convey better understanding of the process, several tests were performed on the fruitlets sterilized under different sterilization conditions, i.e., 40 and 70 psi. Oil released, sludge formation and water absorption during the digestion process were analyzed. It was found that fruitlets sterilized at 70 psi contained more sugar content in the condensate due to more hydrolyzed sterilized fruit. It was also found that fruit sterilized at higher pressure released more oil into the condensate and absorbed more water.
TL;DR: The parasitological and molecular diagnosis of clinically suspected cutaneous leishmaniasis cases were performed using microscopical examination of Giemsa-stained smears of lesion exudates and minicircle kDNA semi nested PCR, respectively and the prevalence of L. tropica in school boys was 1.4% in the total population studied.
TL;DR: In this article, a stable ester was synthesized to overcome the ester hydrolysis problem during the drilling of oil or gas wells using a conventional ester-based drilling fluid.
Abstract: A stable ester was synthesized to overcome the ester hydrolysis problem during the drilling of oil or gas wells using a conventional ester-based drilling fluid. The thermal and hydrolytic stability of the produced ester was high owing to the transesterification method employed in this study. The reaction was performed using 2-ethylhexanol and methyl laureate esters in the presence of sodium methoxide as a catalyst. In order to obtain the optimum synthesis conditions, a response surface methodology (RSM) was appraised based on the central composite design (CCD). The optimum conditions were determined as follows: 0.6 wt.% catalyst, 70°C reaction temperature, 1:1.5 molar ratio, and 11.5 min of reaction time. The results of 77 wt.% 2-ethylhexyl ester (2-EH) illustrated a high agreement between the experimental and RSM models. The reaction product contained 77 wt.% 2-EH and 23% 2-ethylhexanol. The kinematic viscosity was 5 mm2/s at 40°C and 1.5 mm2/sec at 100°C; the specific gravity was 0.854, flash point was ...
TL;DR: In this article, an acid pre-treatment process and a kinetic study for the esterification reaction of Oleum papaveris seminis oil with methanol in the presence of amberlite 120 as a solid catalyst to convert the oil into methyl esters were presented.
Abstract: This paper presents an acid pre-treatment process and a kinetic study for the esterification reaction of Oleum papaveris seminis oil with methanol in the presence of amberlite 120 as a solid catalyst to convert the oil into methyl esters. Response surface methodology (RSM) was applied to optimize the reaction parameters, i.e. reaction time, percentage of the catalyst and volume ratio of methanol to oil. The results revealed that 0.87% w/w of catalyst concentration and 44.70% v/v of methanol to oil ratio provided final free fatty acid (FFA) contents of 0.60% w/w at 102.40 min of reaction time. It proved that the contribution of Amberlite 120 in the esterification of FFA was highly significant. The kinetics of the esterification in Oleum papaveris seminis oil with methanol in the presence of the amberlite 120 catalyst were also investigated to establish the reaction rate constant (k), reaction order, and activation energy. The study was performed under the optimized parameters at three reaction temperatures (50, 55, and 60 oC). The value of k was in the range of 0.013 to 0.027 min-1. The first-order kinetics’ model was suitable for this irreversible FFA esterification with the activation energy of about 60.9 KJ·mol-1.