Chemoselective decarboxylation of ceiba oil to diesel-range alkanes over a red mud based catalyst under H2-free conditions.

Concerns over global greenhouse gas emissions such as CO x and NO x as well as the depletion of petroleum fossil resources have motivated humankind to seek an alternative energy source known as green diesel. In this study, green diesel was produced via a deoxygenation (DO) reaction of ceiba oil under a H2-free atmosphere over Ni modified red mud-based catalysts, which have been synthesized via a precipitation - deep-deposition assisted autoclave method. The obtained catalyst was further characterized by XRF, XRD, BET, FTIR, TPD-NH3, FESEM, and TGA. Based on the catalytic activity test, all Ni/RMO x catalysts facilitated greater DO activity by yielding 83-86% hydrocarbon yield and 70-85% saturated diesel n-(C15 + C17) selectivity. Ni/RMO3 was the best catalyst for deoxygenizing the ceiba oil owing to the existence of a high acidic strength (12717.3 µmol g-1) and synergistic interaction between Fe-O and Ni-O species, thereby producing the highest hydrocarbon yield (86%) and n-(C15 + C17) selectivity (85%). According to the reusability study, the Ni/RMO3 could be reused for up to six consecutive runs with hydrocarbon yields ranging from 53% to 83% and n-(C15 + C17) selectivity ranging from 62% to 83%.

Oxidative stress cytotoxicity induced by platinum-doped magnesia nanoparticles in cancer cells.

The aim of this study was to prepare, characterize, and determine the in vitro anticancer effects of platinum-doped magnesia (Pt/MgO) nanoparticles. The chemical compositions, functional groups, and size of nanoparticles were determined using X-ray diffraction, Fourier transform infrared spectroscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, and scanning electron microscopy. Pt/MgO nanoparticles were cuboid and in the nanosize range of 30-50 nm. The cytotoxicity of Pt/MgO nanoparticles was determined via the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay on the human lung and colonic cancer cells (A549 and HT29 respectively) and normal human lung and colonic fibroblasts cells (MRC-5 and CCD-18Co repectively). The Pt/MgO nanoparticles were relatively innocuous to normal cells. Pt/MgO nanoparticles downregulated Bcl-2 and upregulated Bax and p53 tumor suppressor proteins in the cancer cells. Pt/MgO nanoparticles also induced production of reactive oxygen species, decreased cellular glutathione level, and increased lipid peroxidation. Thus, the anticancer effects of Pt/MgO nanoparticles were attributed to the induction of oxidative stress and apoptosis. The study showed the potential of Pt/MgO nanoparticles as an anti-cancer compound.

Catalytic ketonization of palmitic acid over a series of transition metal oxides supported on zirconia oxide-based catalysts.

Modification of a ZrO2 based catalyst with selected transition metals dopants has shown promising improvement in the catalytic activity of palmitic acid ketonization. Small amounts of metal oxide deposition on the surface of the ZrO2 catalyst enhances the yield of palmitone (16-hentriacontanone) as the major product with pentadecane as the largest side product. This investigation explores the effects of addition of carefully chosen metal oxides (Fe2O3, NiO, MnO2, CeO2, CuO, CoO, Cr2O3, La2O3 and ZnO) as dopants on bulk ZrO2. The catalysts are prepared via a deposition-precipitation method followed by calcination at 550 °C and characterized by XRD, BET-surface area, TPD-CO2, TPD-NH3, FESEM, TEM and XPS. The screening of synthesized catalysts was carried out with 5% catalyst loading onto 15 g of pristine palmitic acid and the reaction carried out at 340 °C for 3 h. Preliminary studies show catalytic activity improvement with addition of dopants in the order of La2O3/ZrO2 < CoO/ZrO2 < MnO2/ZrO2 with the highest palmitic acid conversion of 92% and palmitone yield of 27.7% achieved using 5% MnO2/ZrO2 catalyst. Besides, NiO/ZrO2 exhibits high selectivity exclusively for pentadecane compared to other catalysts with maximum yield of 24.9% and conversion of 64.9% is observed. Therefore, the changes in physicochemical properties of the dopant added ZrO2 catalysts and their influence in palmitic acid ketonization reaction is discussed in detail.

Production of green diesel from catalytic deoxygenation of chicken fat oil over a series binary metal oxide-supported MWCNTs.

Deoxygenation processes that exploit milder reaction conditions under H2-free atmospheres appear environmentally and economically effective for the production of green diesel. Herein, green diesel was produced by catalytic deoxygenation of chicken fat oil (CFO) over oxides of binary metal pairs (Ni-Mg, Ni-Mn, Ni-Cu, Ni-Ce) supported on multi-walled carbon nanotubes (MWCNTs). The presence of Mg and Mn with Ni afforded greater deoxygenation activity, with hydrocarbon yields of >75% and n-(C15 + C17) selectivity of >81%, indicating that decarboxylation/decarbonylation (deCOx) of CFO is favoured by the existence of high amount of lower strength strong acidic sites along with noticeable strongly basic sites. Based on a series of studies of different Mg and Mn dosages (5-20 wt%), the oxygen free-rich diesel-range hydrocarbons produced efficiently by Ni10-Mg15/MWCNT and Ni10-Mn5/MWCNT catalysts yielded >84% of hydrocarbons, with n-(C15 + C17) selectivity of >85%. The heating value of the green diesel obtained complied with the ultra-low sulphur diesel standard.

Efficient deoxygenation of waste cooking oil over Co3O4-La2O3-doped activated carbon for the production of diesel-like fuel.

Untreated waste cooking oil (WCO) with significant levels of water and fatty acids (FFAs) was deoxygenated over Co3O4-La2O3/ACnano catalysts under an inert flow of N2 in a micro-batch closed system for the production of green diesel. The primary reaction mechanism was found to be the decarbonylation/decarboxylation (deCOx) pathway in the Co3O4-La2O3/ACnano-catalyzed reaction. The effect of cobalt doping, catalyst loading, different deoxygenation (DO) systems, temperature and time were investigated. The results indicated that among the various cobalt doping levels (between 5 and 25 wt%), the maximum catalytic activity was exhibited with the Co : La ratio of 20 : 20 wt/wt% DO under N2 flow, which yielded 58% hydrocarbons with majority diesel-range (n-(C15 + C17)) selectivity (∼63%), using 3 wt% catalyst loading at a temperature of 350 °C within 180 min. Interestingly, 1 wt% of catalyst in the micro-batch closed system yielded 96% hydrocarbons with 93% n-(C15 + C17) selectivity within 60 min at 330 °C, 38.4 wt% FFA and 5% water content. An examination of the WCO under a series of FFA (0-20%) and water contents (0.5-20 wt%) indicated an enhanced yield of green diesel, and increased involvement of the deCOx mechanism. A high water content was found to increase the decomposition of triglycerides into FFAs and promote the DO reaction. The present work demonstrates that WCO with significant levels of water and FFAs generated by the food industry can provide an economical and naturally replenished raw material for the production of diesel.

Sulfonated SnO2 nanocatalysts via a self-propagating combustion method for esterification of palm fatty acid distillate.

Biodiesel derived from palm fatty acid distillate (PFAD) was produced via catalytic esterification using sulfonated tin oxide (HSO3 -/SnO2) as the superacid solid catalyst. In this work, the SnO2 catalyst was synthesised by the self-propagating combustion (SPC) method, and activated using chlorosulfonic acid. The SPC method was able to produce nano-sized particles with homogenous size and shape that were anchored with many HSO3 - ions, resulting in more exceptional acid properties that effectively esterified the PFAD feedstock into FAMEs (fatty acid methyl esters). Several studies based on metal oxide-based catalysts were also included for comparison. Under the optimised conditions of 9 : 1 (methanol-to-PFAD molar ratio), 4 wt% (catalyst loading), 100 °C (reaction temperature) and 3 h (reaction time), the FFA conversion and FAME yield were 98.9% and 93.8%, respectively. Besides, the sulfonated SnO2-spc catalyst can be reused in up to five consecutive cycles with an acceptable esterification performance and minimal sulfur leaching. It is worth mentioning that the SPC method is a greener and simpler technique to obtain the nanocatalysts. Overall, the production of FAME from low value, cheaper, abundant, and non-edible PFAD feedstock, assisted by a non-transition metal oxide of sulfonated SnO2 catalyst, could reduce the cost of biodiesel production.

Development of bimetallic nickel-based catalysts supported on activated carbon for green fuel production.

In this work, the catalytic deoxygenation of waste cooking oil (WCO) over acid-base bifunctional catalysts (NiLa, NiCe, NiFe, NiMn, NiZn, and NiW) supported on activated carbon (AC) was investigated. A high hydrocarbon yield above 60% with lower oxygenated species was found in the liquid product, with the product being selective toward n-(C15 + C17)-diesel fractions. The predominance of n-(C15 + C17) hydrocarbons with the concurrent production of CO and CO2, indicated that the deoxygenation pathway proceeded via decarbonylation and decarboxylation mechanisms. High deoxygenation activity with better n-(C15 + C17) selectivity over NiLa/AC exposed the great synergistic interaction between La and Ni, and the compatibility of the acid-base sites increased the removal of oxygenated species. The effect of La on the deoxygenation reaction performance was investigated and it was found that a high percentage of La species would be beneficial for the removal of C-O bonded species. The optimum deoxygenation activity of 88% hydrocarbon yield with 75% n-(C15 + C17) selectivity was obtained over 20% of La, which strongly evinced that La leads to a greater enhancement of the deoxygenation activity. The NiLa/AC reusability study showed consistent deoxygenation reactions with 80% hydrocarbon yield and 60% n-(C15 + C17) hydrocarbon selectivity within 6 runs.

The crucial roles of inflammatory mediators in inflammation: A review.

The inflammatory response is a crucial aspect of the tissues' responses to deleterious inflammogens. This complex response involves leukocytes cells such as macrophages, neutrophils, and lymphocytes, also known as inflammatory cells. In response to the inflammatory process, these cells release specialized substances which include vasoactive amines and peptides, eicosanoids, proinflammatory cytokines, and acute-phase proteins, which mediate the inflammatory process by preventing further tissue damage and ultimately resulting in healing and restoration of tissue function. This review discusses the role of the inflammatory cells as well as their by-products in the mediation of inflammatory process. A brief insight into the role of natural anti-inflammatory agents is also discussed. The significance of this study is to explore further and understand the potential mechanism of inflammatory processes to take full advantage of vast and advanced anti-inflammatory therapies. This review aimed to reemphasize the importance on the knowledge of inflammatory processes with the addition of newest and current issues pertaining to this phenomenon.

A new xanthone from Garcinia nitida.

A detailed chemical study on the stem bark of Garcinia nitida has led to the isolation of five xanthones. They are 1,6-dihydroxy-5-methoxy-6,6-dimethylpyrano[2',3':2,3]-xanthone (1), inophyllin B (2), osajaxanthone (3), 3-isomangostin (4) and rubraxanthone (5). The structures of these compounds were established using mainly 1-D and 2-D NMR spectroscopy ((1)H, (13)C, DEPT, COSY, HMBC and HMQC) while molecular masses were determined via MS techniques; 1 is a new compound.

Performances of toluene removal by activated carbon derived from durian shell.

In the effort to find alternative low cost adsorbent for volatile organic vapors has prompted this research in assessing the effectiveness of activated carbon produced from durian shell in removing toluene vapors. Durian shells were impregnated with different concentrations of H3PO4 followed by carbonization at 500 °C for 20 min under nitrogen atmosphere. The prepared durian shell activated carbon (DSAC) was characterized for its physical and chemical properties. The removal efficiency of toluene by DSAC was performed using different toluene concentrations. Results showed that the highest BET surface area of the produced DSAC was 1404 m2/g. Highest removal efficiency of toluene vapors was achieved by using DSAC impregnated with 30% of acid concentration heated at 500 °C for 20 min heating duration. However, there is insignificant difference between removal efficiency of toluene by DSAC and different toluene concentrations. The toluene adsorption by DSAC was better fitted into Freundlich model.

A new cytotoxic carbazole alkaloid from Clausena excavata.

A new carbazole alkaloid, 3-carbomethoxy-2-hydroxy-7-methoxycarbazole, Clausine-TY (1), together with two known carbazole alkaloid, Clausine-H (2) and Clausine-B (3), were isolated from the ethyl acetate extract of the stem bark of the Malaysian Clausena excavata. The structures of these compounds were elucidated by spectroscopic analyses. The new carbazole alkaloid shows significant cytotoxicity against CEM-SS cell line.

Xanthones from Garcinia mangostana (Guttiferae).

Studies on the stem of Garcinia mangostana have led to the isolation of one new xanthone mangosharin (1) (2,6-dihydroxy-8-methoxy-5-(3-methylbut-2-enyl)-xanthone) and six other prenylated xanthones, alpha-mangostin (2), beta-mangostin (3), garcinone D (4), 1,6-dihydroxy-3,7-dimethoxy-2-(3-methylbut-2-enyl)-xanthone (5), mangostanol (6) and 5,9-dihydroxy-8- methoxy-2,2-dimethyl-7-(3-methylbut-2-enyl)-2H,6H-pyrano-[3,2-b]-xanthene-6-one (7). The structures of these compounds were determined by spectroscopic methods such as 1H NMR, 13C NMR, mass spectrometry (MS) and by comparison with previous studies. All the crude extracts when screened for their larvicidal activities indicated very good toxicity against the larvae of Aedes aegypti. This article reports the isolation and identification of the above compounds as well as bioassay data for the crude extracts. These bioassay data have not been reported before.

Mucigerin, a new coumarin from Calophyllum mucigerum (Guttiferae).

Our recent studies on the stem bark of Calophyllum mucigerum (Guttiferae) have yielded a new coumarin mucigerin, a prenylated xanthone cudraxanthone C and the common steroidal triterpenes friedelin and stigmasterol. Structural elucidations of these compounds were achieved using 1H NMR, 13C NMR, DEPT, COSY, HETCOR and HMBC experiments while MS gave the molecular masses. Cytotoxic assays using CEM-SS cell line (T-lymphoblastic leukemia) on the crude extracts of the stem bark indicated some activity. The crude extracts were also found to be moderately toxic against the larvae of Aedes aegypti. This article reports the isolation and identification of mucigerin as well as bioassay data.