Showing papers by "Umer Rashid published in 2018"
TL;DR: In this article, a step-by-step process of converting waste cooking oil (WCO) to biodiesel, using modified waste egg shell catalyst, is presented, which is able to convert the high free fatty acid (FFA) content waste cooking oils to FAME efficiently under moderate reaction conditions.
Abstract: Global energy crisis are as a result of gradual depletion of fossil fuel reserves, coupled with population growth in developing countries. Besides, fossil fuels are not environmentally benign as they are associated with problems, i.e. global warming, high toxicity and non biodegradability, hence it is considered as non sustainable source of energy. Without doubt, biofuel-based energy is a promising long-term energy source that can reduce the over dependence on fossil fuels as a result of feedstocks availability and renewability. However, biodiesel production from vegetable oil using the traditional homogeneous catalytic system is no longer defensible by industries in the near future, particularly due to food-fuel rivalry and ecological problems related to the conventional homogeneous catalytic system. This review presents a comprehensive step by step process of converting waste cooking oil (WCO) to biodiesel, using modified waste egg shell catalyst. The modified waste egg shell derived bi-functional catalyst could easily be removed from the fatty acid methyl esters (FAME) with limited environmental effects. The new modified catalytic system is able to convert the high free fatty acid (FFA) content waste cooking oil to FAME efficiently under moderate reaction conditions. Utilization of waste cooking oil as a feedstock for biodiesel production will reduce the food security issues that stem the biodiesel production from food-grade oil. Moreover, it will reduce the total production cost of the FAME due to its low cost. The major objective of this article is to demonstrate the current state of the use of heterogeneous bifunctional acid/base catalyst to produce biodiesel from green and non-edible waste cooking oil. At the end of the article, perspectives and future developments are also presented.
151 citations
TL;DR: A preliminary assessment of biodiesel production from waste sources available in the Kingdom of Saudi Arabia for energy generation and solution for waste disposal issues found challenges in commercialization of waste to biodiesel facilities in KSA, including waste collection and separation, impurities, reactor design and biodiesel quality.
93 citations
TL;DR: It was showed that date seed had great nutritional value due to which it can be used for food applications especially as frying or cooking oil, and has the potential to be used in the food industry as an abundant alternative to palm olein.
Abstract: This investigation aimed to evaluate the chemical composition and physicochemical properties of seed oils from 6 date palm (Phoenix. dactyliferaL.) cultivars (Barhi, Khalas, Manifi, Rezeiz, Sulaj, and Sukkari) growing in Saudi Arabia and to compare them with conventional palm olein. The mean oil content of the seeds was about 7%. Oleic acid (48.67%) was the main fatty acid, followed by lauric acid (17.26%), stearic acid (10.74%), palmitic acid (9.88%), and linolenic acid (8.13%). The mean value for free fatty acids content was 0.5%. The P. dactyliferaseed oil also exhibited a mean tocol content of 70.75 mg/100 g. α‐Tocotrienol was the most abundant isomer (30.19%), followed by γ‐tocopherol (23.61%), γ‐tocotrienol (19.07%), and α‐tocopherol (17.52%). The oils showed high thermal and oxidative stabilities. The findings indicate that date seed oil has the potential to be used in the food industry as an abundant alternative to palm olein. This study showed that date seed had great nutritional value due to which it can be used for food applications especially as frying or cooking oil. In addition, date oil has also potential to be used in cosmetic and pharmaceutical practices as well. The extraction of oil from Phoenix dactyliferaseed on large scale can create positive socioeconomic benefits especially for rural communities and could also assist to resolve the environmental issues generated by excess date production in large scale date‐producing countries such as Saudi Arabia.
71 citations
TL;DR: Azo dyes are widely used in textile, fiber, cosmetic, leather, paint and printing industries and have the ability to be used as drug carriers, either by acting as a 'cargo' that entrap therapeutic agents or by prodrug approach.
Abstract: Azo dyes are widely used in textile, fiber, cosmetic, leather, paint and printing industries. Besides their characteristic coloring function, azo compounds are reported as antibacterial, antiviral, antifungal and cytotoxic agents. They have the ability to be used as drug carriers, either by acting as a 'cargo' that entrap therapeutic agents or by prodrug approach. The drug is released by internal or external stimuli in the region of interest, as observed in colon-targeted drug delivery. Besides drug-like and drug carrier properties, a number of azo dyes are used in cellular staining to visualize cellular components and metabolic processes. However, the biological significance of azo compounds, especially in cancer chemotherapy, is still in its infancy. This may be linked to early findings that declared azo compounds as one of the possible causes of cancer and mutagenesis. Currently, researchers are screening the aromatic azo compounds for their potential biomedical use, including cancer diagnosis and therapy. In this review, we highlight the medical applications of azo compounds, particularly related to cancer research. The biomedical significance of cis-trans interchange and negative implications of azo compounds are also discussed in brief.
60 citations
TL;DR: A detailed discussion on the advantages and feasibility of catalysts for biodiesel production, which are both environmentally and economically viable as compared to conventional homogeneous catalysts is presented in this article.
Abstract: Abstract Due to increasing concerns about global warming and dwindling oil supplies, the world’s attention is turning to green processes that use sustainable and environmentally friendly feedstock to produce renewable energy such as biofuels. Among them, biodiesel, which is made from nontoxic, biodegradable, renewable sources such as refined and used vegetable oils and animal fats, is a renewable substitute fuel for petroleum diesel fuel. Biodiesel is produced by transesterification in which oil or fat is reacted with short chain alcohol in the presence of a catalyst. The process of transesterification is affected by the mode of reaction, molar ratio of alcohol to oil, type of alcohol, nature and amount of catalysts, reaction time, and temperature. Various studies have been carried out using different oils as the raw material; different alcohols (methanol, ethanol, butanol); different catalysts; notably homogeneous catalysts such as sodium hydroxide, potassium hydroxide, sulfuric acid, and supercritical fluids; or, in some cases, enzymes such as lipases. This article focuses on the application of heterogeneous catalysts for biodiesel production because of their environmental and economic advantages. This review contains a detailed discussion on the advantages and feasibility of catalysts for biodiesel production, which are both environmentally and economically viable as compared to conventional homogeneous catalysts. The classification of catalysts into different categories based on a catalyst’s activity, feasibility, and lifetime is also briefly discussed. Furthermore, recommendations have been made for the most suitable catalyst (bifunctional catalyst) for low-cost oils to valuable biodiesel and the challenges faced by the biodiesel industry with some possible solutions.
59 citations
TL;DR: In this paper, a series of catalysts consisting of palladium and gold nanoparticles loaded on carbon (Au-Pd/C) were synthesized and evaluated for the liquid phase oxidation of benzyl alcohol to benzaldehyde.
52 citations
TL;DR: In this paper, waste shells derived calcium-based catalysts were synthesized via wet-impregnation process in the presence of Mo-Zr mixed salt, which demonstrated a superior catalytic performance in transesterification reaction.
51 citations
TL;DR: Binding mode analysis of the most active inhibitors of the DHPM-2-ones showed that these are well accommodated into the binding site of enzyme though stable hydrogen bonding and hydrophobic interactions.
47 citations
TL;DR: In this article, the authors used response surface methodology (RSM) with central composite rotatable design for the conversion of palm fatty acid distillate (PFAD) to fatty acid methyl esters (FAME).
45 citations
TL;DR: Investigating the antinociceptive, antioxidant and anti-cholinesterase potentials of essential oils from I. rugosus revealed that Ir.EO is a rich source of bioactive compounds as obvious from the GC-MS results.
Abstract: Isodon rugosus Wall. ex. Benth is an important species and is used in folk medicine for different types of pains such as abdominal pain, earache, toothache, gastric, and generalized body pain. Recently, we also have reported the antinociceptive potential of chloroform fraction of I. rugosus. In this research, we have investigated the antinociceptive, antioxidant and anti-cholinesterase potentials of essential oils from I. rugosus (Ir.EO), and have determined a possible mechanism of anti-nociception. The Ir.EO was subjected to gas chromatography-mass spectroscopy analysis to find out its chemical constituents. The Ir.EO was assayed for analgesic potential following acetic acid induced writhing, formalin test and hot plate method in animal models. The antioxidant activity was conducted against DPPH and ABTS free radicals following spectroscopic analysis. The cholinesterase inhibitory assays were performed using Ellman's assay. The GC-MS analysis of Ir.EO revealed the identification of 141 compounds. Ir.EO demonstrated strong antinociceptive potential in all three in-vivo models. With the use of nalaxone, it was confirmed that the essential oil was acting on the central pathway of nociception. The Ir.EO also exhibited strong free radicals scavenging potential, exhibiting IC50 values of 338 and 118 μg/ml for DPPH and ABTS free radicals respectively. In AChE and BChE inhibitory assays, the observed IC50 values were 93.56 and 284.19 μg/ml respectively. The encouraging antinociceptive, antioxidant and anticholinesterase results revealed that Ir.EO is a rich source of bioactive compounds as obvious from the GC-MS results.
45 citations
TL;DR: In this paper, a biologically active Schiff base compound was synthesized by condensation reaction of 2-hydroxybenzaldehyde with 3,5-diamino-1,2,4-triazole.
TL;DR: The chiral stationary phase for high-performance liquid chromatography shows good chiral recognition ability and the ability to discriminate between Na6(CO3)(SO4) and Na2SO4, which are two of the four major mineral components of Na2CO3.
Abstract: In the current research work,eleven metal complexes were synthesized from the hydrazide derivative of ursolic acid. Metal complexes of tin, antimony and iron were synthesized and characterized by FT-IR and NMR spectroscopy. The antibacterial and antioxidant activities were performed for these complexes, which revealed that the metal complexes synthesized are more potent than their parent compounds. We observed that antioxidant activity showed by triphenyltin complex was significant and least activity have been shown by antimony trichloride complex.The synthesized metal complexes were then evaluated against two Gram-negative and two Gram-positive bacterial strains. Triphenyl tin complex emerged as potent antibacterial agent with MIC value of 8 μg/ml each against Shigellaspp, S. typhi and S. aureus. While, the MIC value againstS. pneumoniae is 4 μg/ml.Computational docking studies were carried out on molecular targets to interpret the results of antioxidant and antibacterial activities. Based on the results, it may be inferred that the metal complexes of ursolic acid are more active as compared to the parent drug and may be proved for some other pharmacological potential by further analysis.
TL;DR: The findings in this study can justify the use of these novel materials as a potential candidate for green luminescent optoelectronic applications and match well with band gap obtained from the Mott and Davis model for direct transition.
Abstract: Willemite is a wide band gap semiconductor used in modern day technology for optoelectronics application. In this study, a new simple technique with less energy consumption is proposed. Willemite nanoparticles (NPs) were produced via a water–based solution consisting of a metallic precursor, polyvinylpyrrolidone (PVP), and underwent a calcination process at 900 °C for several holding times between 1–4 h. The FT–IR and Raman spectra indicated the presence of metal oxide bands as well as the effective removal of PVP. The degree of the crystallization and formation of the NPs were determined by XRD. The mean crystallite size of the NPs was between 18.23–27.40 nm. The morphology, particle shape and size distribution were viewed with HR-TEM and FESEM analysis. The willemite NPs aggregate from the smaller to larger particles with an increase in calcination holding time from 1–4 h with the sizes ranging between 19.74–29.71 nm. The energy values obtained from the experimental band gap decreased with increasing the holding time over the range of 5.39 eV at 1 h to at 5.27 at 4 h. These values match well with band gap obtained from the Mott and Davis model for direct transition. The findings in this study are very promising and can justify the use of these novel materials as a potential candidate for green luminescent optoelectronic applications.
TL;DR: In vitro antibacterial evaluation of some new amino acid conjugated antimicrobial drugs, triazine skeleton proved beneficial for the increase in hydrophobicity and potency and 4-amino unsubstituted trimethoprim-triazine derivative 7b have shown superior activity.
TL;DR: The novel process of two-stage continuous physical activation method was able to expose mesopores and micropores that were previously covered/clogged in nature, and simultaneously create new pores, which meets the recent industrial adsorbent requirements such as low activation temperature, high fixed carbon content, high yield, high adsorption properties and high surface area.
Abstract: In the present study, agricultural biomass-palm kernel shell (PKS) and coconut shell (CS)-was used to produce high porosity bioadsorbent using two-stage continuous physical activation method with different gas carrier (air and N2) in each stage. The activation temperature was set constant at 600, 700, 800 or 900°C for both activation stages with the heating rate of 3°C min-1. Two parameters, the gas carrier and activation temperature, were determined as the significant factors on the adsorption properties of bioadsorbent. BET, SEM, FTIR, TGA, CHNS/O and ash content were used to elucidate the developed bioadsorbent prepared from PKS and CS and its capacity towards the adsorption of methylene blue and iodine. The novel process of two-stage continuous physical activation method was able to expose mesopores and micropores that were previously covered/clogged in nature, and simultaneously create new pores. The synthesized bioadsorbents showed that the surface area (PKS: 456.47 m2 g-1, CS: 479.17 m2 g-1), pore size (PKS: 0.63 nm, CS: 0.62 nm) and pore volume (PKS: 0.13 cm3 g-1, CS: 0.15 cm3 g-1) were significantly higher than that of non-treated bioadsorbent. The surface morphology of the raw materials and synthesized bioadsorbent were accessed by SEM. Furthermore, the novel process meets the recent industrial adsorbent requirements such as low activation temperature, high fixed carbon content, high yield, high adsorption properties and high surface area, which are the key factors for large-scale production of bioadsorbent and its usage.
TL;DR: In this article, the authors investigated the deposition precipitation, pore volume impregnation and hydrothermal methods of synthesizing activated carbon monolith supported metal oxide adsorbent (Co3O4/ACM).
TL;DR: Investigations were extended to explore the mechanism of enzyme inhibition and docking analysis by using Molecular Operating Environment (MOE 2016.08) and a homology model for α-glucosidase was constructed and validated using Ramachandran plot.
TL;DR: In this paper, a char-based acid catalyst was synthesized by the sulfonation of gasification char with sulfuric acid, which showed an interesting efficiency in decreasing free fatty acid of WCO and a considerable recyclability of the catalyst.
TL;DR: Molecular docking correlations suggest that the compounds exerted their inhibitory activity by binding to the active of the enzyme in the synthesized derivatives of progesterone and testosterone.
TL;DR: This study concludes that plant mediated biosynthesis of nanoparticles is the superior alternative compared to chemical and physical approaches, to utilize them as drug delivery tool and need to conjugate apoptosis inducing biological agents with silver nanoparticles to suppress the uncontrolled division of cancer cells.
Abstract: Green synthesis of metallic nanoparticles has attracted a great deal of attention from scientific community due to its biocompatibility and environment friendly nature. In the present study, silver nanoparticles were biologically synthesized using leave extracts of Litchi chinensis. Biosynthesized silver nanoparticles were characterized and their applications were observed by different methodologies. Bio-reduction reaction was confirmed by the surface plasmon resonance of silver nanoparticles at 417 nm through UV-VIS spectrophotometer. FTIR analysis revealed that the amine groups present in the leaf extracts were responsible for the reduction of silver ions to silver nanoparticles. X-ray diffraction analysis was used to determine the crystalline nature of silver nanoparticles and their diameter was noted in the range of 41-55 nm by scanning electron microscopy. Antibacterial activity was observed against gram positive and gram negative strains of bacteria. Furthermore, human epithelial type 2 cancer cells (HEp-2) and Human breast adenocarcinoma cells lines (MCF-7) were treated with the biosynthesized silver nanoparticles using MTT assay. The resulting cell death rate was noted up to 40.91+1.99%. This study concludes that plant mediated biosynthesis of nanoparticles is the superior alternative compared to chemical and physical approaches, to utilize them as drug delivery tool and need to conjugate apoptosis inducing biological agents with silver nanoparticles to suppress the uncontrolled division of cancer cells.
TL;DR: Tareq et al. as mentioned in this paper used carbon and titanium oxide (TiO 2 ) as supports for solvent free liquid phase oxidation of benzyl alcohol, and found that the synthesized Au-Pd/ activated carbon catalyst was beneficial for the solvent free oxidation of alcohol after its high surface area measuring 871 m 2 g -1.
Abstract: The solvent free oxidation of benzyl alcohol was conducted employing Au and Pd supported catalysts, while utilizing hydrogen peroxide 35% (H 2 O 2 ) as the oxidant, H 2 O 2 is very cheap, mild, and an environment friendly reagent, which produced water as the only by-product. Various proportions of Au-Pd catalysts on carbon and titanium oxide activated as supports were synthesized through the use of sol immobilization catalyst synthesis technique. Characterization of the synthesized catalysts was performed using X-Ray Diffraction (XRD), Brunauer-Emmett-Teller (BET), Field Emission Scanning Electron Microscopy (FESEM), and Transmission Electron Microscopy (TEM). It was found that the synthesized Au-Pd/ activated carbon catalyst was beneficial for the solvent free oxidation of benzyl alcohol after its containing high surface area measuring 871 m 2 g -1 . Analysis of the TEM data and particle dimension revealed smaller and narrower particle size of 1 wt%. Thus, the distribution of Au-Pd/C was attained. Carbon-supported bimetallic catalysts presented a higher conversion compared to catalysts that are supported titanium oxide (TiO 2 ) for for the oxidation reaction of benzyl alcohol. It was determined that this technique was a suitable process for catalyst synthesis with high selectivity, same distribution of the particle size and activations. Copyright © 2018 BCREC Group. All rights reserved Received: 8 th May 2017; Revised: 22 nd February 2018; Accepted: 6 th March 2018; Available online: 11 st June 2018; Published regularly: 1 st August 2018 How to Cite : Sanaa Tareq, S., Saiman, M.I., Yun Hin, T.Y., Abdullah, A.H., Rashid, U. (2018). The Impact of Hydrogen Peroxide as An Oxidant for Solvent-free Liquid Phase Oxidation of Benzyl Alcohol using Au-Pd Supported Carbon and Titanium Catalysts. Bulletin of Chemical Reaction Engineering & Catalysis , 13 (2): 373-385 (doi:10.9767/bcrec.13.2.1204.373-385)
TL;DR: Four new 3-(2-Phenyl-5-substituted phenyl-4,5-dihydropyrazol-1-yl)thiazol-4-yl)-2H-chromen-2-one derivatives were synthesized and fully characterized by spectroscopic techniques, and compound 3 emerged as the most potent derivative in acetylcholine esterase (AChE) inhibition assay.
TL;DR: In this article, a new surfactant with different functionalities has been synthesized to examine its CO2-philicity, which is essential if the CO2 foam is intended to augment a water flooding process as a method to displace oil from a reservoir.
Abstract: The ability of surfactants to interact with CO2 is essential if the CO2 foam is intended to augment a water flooding process as a method to displace oil from a reservoir. Apart from improved sweep efficiency of foam, CO2 reduces the oil viscosity, causes the oil to swell, lowers the high interfacial tension between oil and rock, dislodges the immobile oil, and hence increases the volumetric sweep efficiency. The surfactant must possess suitable structure to successfully play these roles. In this context, a new surfactant with different functionalities has been synthesized to examine its CO2-philicity. The surfactant was evaluated for the enhanced oil recovery (EOR) suitability by firstly examining the fluid–fluid compatibility in various temperatures, salinity, and hardness conditions. The foaming properties were also assessed. The interfacial tension (IFT) between the surfactant and CO2 gas at 90 °C and up to 2700 psi pressure revealed some interesting findings. The IFT of CO2–brine without surfactant dropped from a value of 70 to 30 mN/m when CO2 critical pressure approached 1070 psi, and it remained at 30 mN/m at higher pressures. The incorporation of surfactant achieved the lowest IFT of 1.76 mN/m at critical pressure conditions at 90 °C. The foam stability of the surfactants was also evaluated. In the core flooding test, the mobility reduction factor (MRF) values reflected the same trend as that of IFT lowering and foam stability. The three-tailed surfactant showed the MRF of 3.4 while alpha olefin sulfonate (AOS) (commercial surfactant) had the MRF value of 1.3. The three-tailed surfactant provided the highest recovery of 96% of residual oil in place (ROOIP). The adsorption of the surfactant was low at less than 0.5 mg/g.
TL;DR: In this article, the performance of activated carbon modified by hydrothermal treatment and impregnation techniques was compared using metal oxides, and it was found that activated carbon that had been hydrothermally treated with cerium oxide (CeO2) had the highest adsorption capacity of 0.856 mmol/g with a breakthrough time of 19.33 min.
Abstract: Activated carbon (AC) has been used widely as an agent for carbon dioxide (CO2) adsorption due to its environmentally friendly nature, low cost, high porous structure, high surface area and good mechanical properties. Modifications have been made to AC in order to enhance its adsorptive properties. In this study, the performance of activated carbon modified by hydrothermal treatment and impregnation techniques was compared using metal oxides. The prepared samples were characterized by different techniques using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The adsorption of CO2 was investigated using a CO2 adsorption unit, whereby 20% of CO2 gas was passed through the samples until a breakthrough point was achieved. During the adsorption study, it was found that AC that had been hydrothermally treated with cerium oxide (CeO2) had the highest adsorption capacity of 0.856 mmol/g with a breakthrough time of 19.33 min.
TL;DR: In this article, the authors used differential scanning calorimetry (DSC) to characterize and evaluate the seed oil extracted from Y. aloifolia seeds and found that the oil contained tocotrienols, which represent 79% of the total amount of tocols.
Abstract: Yucca aloifolia Linn (Y. aloifolia), also known as Spanish bayonet, is a drought-tolerant plant containing important bioactive compounds in various parts of the plant. Y. aloifolia is used as a natural medicinal herb. The purpose of the present study was to characterize and evaluate the seed oil extracted from Y. aloifolia seeds. The oil content of the seeds was 16.23%. The principal fatty acids in the oil were linoleic acid (73.38%), oleic acid (13.52%) and palmitic acid (8.18%). The oil has high vitamin E activity because of an appreciable concentration of tocols (204 mg/100 g), particularly tocotrienols, which represent 79% of the total amount of tocols. Tocotrienols have powerful antioxidant, anticancer, neuro/cardio protective and cholesterol-lowering properties. The thermal profile of Y. aloifolia seed oil was examined differential scanning calorimetry (DSC). Y. aloifolia seed oil is considered to be healthy dietary oil.
TL;DR: Based on the insights gained from structures of virtual screening hits, a scaffold was designed using 1,3,4-oxadiazole as the basic structural feature and SAR studies were carried out for the optimization of this scaffold.
TL;DR: In this article, the surface area of activated carbon monolith (ACM) was improved by acid modification, furfuryl alcohol coating, carbonization (at 800 o C) and subsequent activation under CO2 atmosphere.
Abstract: The multi-step SO2 and NOx removal techniques is complex process with high capital cost, high risk in solvent losses, unwanted foaming, flooding, and equipment fouling. Therefore, the simultaneously SO2/NOx removal from flue gas by adsorption alternative offers economical and environmental benefits. In this study, the surface area of monolith was improved by acid modification, furfuryl alcohol coating, carbonization (at 800 o C) and subsequent activation under CO2 atmosphere. The activated carbon monolith (ACM) was impregnated with tricobalt tetraoxide (Co3O4) catalyst by three different synthesis methods namely hydrothermal, deposition precipitation and the pore volume impregnation. The fixed bed adsorption test for simultaneous SO2/NOx removal showed that the adsorbent synthesized by hydrothermal method (HM-Co3O4/ACM) exhibited high adsorption capacity (123.1 and 130.2 mg/g for SO2 and NOx) with the breakthrough times of 86 and 124 min respectively. This finding indicated that the adsorbent’s unique ability to high NOx adsorption affinity a major breakthrough. About 1.1% Co3O 4 was impregnated in the ACM mesoporous ( ≈ 38 nm) dominated adsorbents meanwhile, thermal decomposition that may be attributed to the oxidation of carbonaceous species and Co3O4 occurred. The regeneration study and characterization of the HM-Co3O4/ACM adsorbent proved its stability and potentiality to industrial application.
TL;DR: The efficient one-pot synthesis of 3,4-biaryl-2,5-dichlorothiophene derivatives (2a–2i) via a palladium-catalyzed Suzuki cross-coupling reaction is reported to investigate their potential as non-linear optical materials and significant βo values were found for the 2b and 2g derivatives.
Abstract: We report herein the efficient one-pot synthesis of 3,4-biaryl-2,5-dichlorothiophene derivatives (2a–2i) via a palladium-catalyzed Suzuki cross-coupling reaction. A series of thiophene derivatives were synthesized, starting from 3,4-dibromo-2,5-dichlorothiophene (1) and various arylboronic acids using Pd(PPh3)4 and K3PO4 with moderate to good yields. For further insights about the structure and property relationship, density functional theory (DFT) calculations were performed. A relaxed potential energy surface (PES) scan was performed to locate the minimum energy structure. A frontier molecular orbitals analysis was performed to explain the reactivity of all synthesized derivatives. As the synthesized derivatives had extended conjugations, therefore the first hyperpolarizability (βo) was calculated to investigate their potential as non-linear optical (NLO) materials and significant βo values were found for the 2b and 2g derivatives.
TL;DR: The reaction time for the transesterification of HOPME with NPG to produce NPG diester was successfully reduced to 1 hour from the 14 hours required in the earlier synthesis method and the excess reactant was no longer methyl ester but the alcohol (NPG).
Abstract: Background The transesterification of high oleic palm oil methyl ester (HOPME) with neopentyl glycol (NPG) has been investigated The present study revealed the application of low-pressure technology as a new synthesis method to produce NPG diesters Single variable optimization and response surface methodology (RSM) were implemented to optimize the experimental conditions to achieve the maximum composition (wt%) of NPG diesters Objective The main objective of this study was to optimize the production of NPG diesters and to characterize the optimized esters with typical chemical, physical and electrical properties to study its potential as insulating oil Methods The transesterification reaction between HOPME and NPG was conducted in a 1L three-neck flask reactor at specified temperature, pressure, molar ratio and catalyst concentration For the optimization, four factors have been studied and the diester product was characterized by using gas chromatography (GC) analysis The synthesized esters were then characterized with typical properties of transformer oil such as flash point, pour point, viscosity and breakdown voltage and were compared with mineral insulating oil and commercial NPG dioleate For formulation, different samples of NPG diesters with different concentration of pour point depressant were prepared and each sample was tested for its pour point measurement Results The optimum conditions inferred from the analyses were: molar ratio of HOPME to NPG of 2:13, temperature = 182°C, pressure = 06 mbar and catalyst concentration of 12% The synthesized NPG diesters showed very important improvement in fire safety compared to mineral oil with flash point of 300°C and 155°C, respectively NPG diesters also exhibit a relatively good viscosity of 21 cSt The most striking observation to emerge from the data comparison with NPG diester was the breakdown voltage, which was higher than mineral oil and definitely in conformance to the IEC 61099 limit at 675 kV The formulation of synthesized NPD diesters with VISCOPLEX® pour point depressant has successfully increased the pour point of NPG diester from -14°C to -48°C Conclusion The reaction time for the transesterification of HOPME with NPG to produce NPG diester was successfully reduced to 1 hour from the 14 hours required in the earlier synthesis method The main highlight of this study was the excess reactant which is no longer methyl ester but the alcohol (NPG) The optimum reaction conditions for the synthesis were molar ratio of 2:113 for NPG:HOPME, 182°C, 06 mbar and catalyst concentration of 12 wt% The maximum NPG diester yield of 87 wt% was consistent with the predicted yield of 877 wt% obtained from RSM The synthesized diester exhibited better insulating properties than the commercial products especially with regards to the breakdown voltage, flash point and moisture content
Journal Article•
TL;DR: N-(Substituted)-5-(1-(4-methoxyphenylsulfonyl)piperidin-4-yl)-4H-1,2,4-triazol-3-ylthio) acetamide were synthesized by following conventional as well as microwave assisted protocol through five consecutive steps under the impact of various reaction conditions to control the reaction time and the yield of product.
Abstract: N-(Substituted)-5-(1-(4-methoxyphenylsulfonyl)piperidin-4-yl)-4H-1,2,4-triazol-3-ylthio) acetamide were synthesized by following conventional as well as microwave assisted protocol through five consecutive steps under the impact of various reaction conditions to control the reaction time and the yield of product. Starting from 4-methoxybenzenesulfonyl chloride and ethyl isonipecotate, product 3 was obtained which was converted into product 4 by treating with hydrazine hydrate. In step 3, the product 4 was refluxed with methyl isothiocyanate and KOH to yield compound 5 which was finally treated with variety of N-substituted acetamides to yield an array of different new compounds (8a-k). These synthesized compounds were evaluated for their inhibition potential against bovine carbonic anhydrase (bCA-II), acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes. Compound 8g demonstrated good activity against bCA-II, AChE and BChE with IC50 values of 8.69 ± 0.38 μM, 11.87±0.19 μM and 26.01±0.55 μM respectively. SAR studies assisted with molecular docking were carried out to explore the mode of binding of the compounds against the studied enzymes.