scholarly journals Influence of Heterogeneous Catalysts and Reaction Parameters on the Acetylation of Glycerol to Acetin: A Review

2020 ◽  
Vol 10 (20) ◽  
pp. 7155
Author(s):  
Usman Idris Nda-Umar ◽  
Irmawati Binti Ramli ◽  
Ernee Noryana Muhamad ◽  
Norsahida Azri ◽  
Uchenna Fidelis Amadi ◽  
...  
Keyword(s):  
Heterogeneous Catalysts ◽  
Critical Role ◽  
Economic Value ◽  
Biodiesel Production ◽  
Molar Ratio ◽  
Fuel Additive ◽  
Reaction Parameters ◽  
The Many ◽  
Catalyst Load

Glycerol, a polyhydric alcohol, is currently receiving greater attention worldwide in view of its glut in the market occasioned by the recent upsurge in biodiesel production. The acetylation of glycerol to acetin (acetyl glycerol) is one of the many pathways of upgrading glycerol to fine chemicals. Acetin, which could be mono, di, and or triacetin, has versatile applications in the cosmetics, medicines, food, polymer, and fuel industries as a humectant, emulsifier, plasticizer, and fuel additive and so it is of high economic value. Given the critical role of catalysts in green chemistry, this paper reports the influence of the different heterogeneous catalysts used in glycerol acetylation. It also reviewed the influence of catalyst load, temperature, molar ratio, and the time on the reaction.

scholarly journals Role of Somatostatin in the Regulation of Central and Peripheral Factors of Satiety and Obesity

2020 ◽  
Vol 21 (7) ◽  
pp. 2568
Author(s):  
Ujendra Kumar ◽  
Sneha Singh
Keyword(s):  
Food Intake ◽  
Hormonal Regulation ◽  
Critical Role ◽  
Eating Behaviour ◽  
Peripheral Tissues ◽  
Complex Process ◽  
The Many ◽  
The One ◽  
Food Seeking

Obesity is one of the major social and health problems globally and often associated with various other pathological conditions. In addition to unregulated eating behaviour, circulating peptide-mediated hormonal secretion and signaling pathways play a critical role in food intake induced obesity. Amongst the many peptides involved in the regulation of food-seeking behaviour, somatostatin (SST) is the one which plays a determinant role in the complex process of appetite. SST is involved in the regulation of release and secretion of other peptides, neuronal integrity, and hormonal regulation. Based on past and recent studies, SST might serve as a bridge between central and peripheral tissues with a significant impact on obesity-associated with food intake behaviour and energy expenditure. Here, we present a comprehensive review describing the role of SST in the modulation of multiple central and peripheral signaling molecules. In addition, we highlight recent progress and contribution of SST and its receptors in food-seeking behaviour, obesity (orexigenic), and satiety (anorexigenic) associated pathways and mechanism.

Current scenario of catalysts for biodiesel production: a critical review

2018 ◽  
Vol 34 (2) ◽  
pp. 267-297 ◽  
Author(s):  
Farrukh Jamil ◽  
Lamya Al-Haj ◽  
Ala’a H. Al-Muhtaseb ◽  
Mohab A. Al-Hinai ◽  
Mahad Baawain ◽  
...  
Keyword(s):  
Heterogeneous Catalysts ◽  
Low Cost ◽  
Bifunctional Catalyst ◽  
Raw Material ◽  
Biodiesel Production ◽  
Molar Ratio ◽  
Homogeneous Catalysts ◽  
Animal Fats ◽  
Current Scenario ◽  
Short Chain Alcohol

AbstractDue 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.

scholarly journals Calcium Oxide Derived from Waste Shells of Mussel, Cockle, and Scallop as the Heterogeneous Catalyst for Biodiesel Production

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Achanai Buasri ◽  
Nattawut Chaiyut ◽  
Vorrada Loryuenyong ◽  
Phatsakon Worawanitchaphong ◽  
Sarinthip Trongyong
Keyword(s):  
Calcium Oxide ◽  
Heterogeneous Catalysts ◽  
Biodiesel Production ◽  
Molar Ratio ◽  
Catalyst Loading ◽  
X Ray ◽  
Bet Method ◽  
Xrf Scanning ◽  
Waste Shell ◽  
Calcination Method

The waste shell was utilized as a bioresource of calcium oxide (CaO) in catalyzing a transesterification to produce biodiesel (methyl ester). The economic and environmen-friendly catalysts were prepared by a calcination method at 700–1,000°C for 4 h. The heterogeneous catalysts were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), and the Brunauer-Emmett-Teller (BET) method. The effects of reaction variables such as reaction time, reaction temperature, methanol/oil molar ratio, and catalyst loading on the yield of biodiesel were investigated. Reusability of waste shell catalyst was also examined. The results indicated that the CaO catalysts derived from waste shell showed good reusability and had high potential to be used as biodiesel production catalysts in transesterification of palm oil with methanol.

scholarly journals Biodiesel Production over Niobium-Containing Catalysts: A Review

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5506
Author(s):  
Daniel Carreira Batalha ◽  
Márcio José da Silva
Keyword(s):  
Catalytic Activity ◽  
Active Sites ◽  
Heterogeneous Catalysts ◽  
Raw Materials ◽  
Catalytic Performance ◽  
High Specific Surface Area ◽  
Biodiesel Production ◽  
Molar Ratio ◽  
Main Reaction ◽  
High Catalytic Activity

Nowadays, the synthesis of biofuels from renewable raw materials is very popular. Among the various challenges involved in improving these processes, environmentally benign catalysts compatible with an inexpensive feedstock have become more important. Herein, we report the recent advances achieved in the development of Niobium-containing heterogeneous catalysts as well as their use in routes to produce biodiesel. The efficiency of different Niobium catalysts in esterification and transesterification reactions of lipids and oleaginous raw materials was evaluated, considering the effect of main reaction parameters such as temperature, time, catalyst load, and oil:alcohol molar ratio on the biodiesel yield. The catalytic performance of Niobium compounds was discussed considering the characterization data obtained by different techniques, including NH3-TPD, BET, and Pyr-FT-IR analysis. The high catalytic activity is attributed to its inherent properties, such as the active sites distribution over a high specific surface area, strength of acidity, nature, amount of acidic sites, and inherent mesoporosity. On top of this, recycling experiments have proven that most Niobium catalysts are stable and can be repeatedly used with consistent catalytic activity.

scholarly journals Solketal Production by Glycerol Acetalization Using Amberlyst-15 Catalyst

2020 ◽  
Vol 20 (1) ◽  
pp. 67
Author(s):  
Hary Sulistyo ◽  
Edwin Nur Huda ◽  
Tri Sarifah Utami ◽  
Wahyudi Budi Sediawan ◽  
Suprihastuti Sri Rahayu ◽  
...  
Keyword(s):  
Kinetic Model ◽  
Cetane Number ◽  
Biodiesel Production ◽  
Molar Ratio ◽  
Catalyst Loading ◽  
Fuel Additive ◽  
Stirrer Speed ◽  
Glycerol Conversion ◽  
Amberlyst 15 ◽  
Operation Conditions

Glycerol, as a by-product of biodiesel production, has recently increased due to the rapid growth of the biodiesel industry. Glycerol utilization is needed to increase the added value of glycerol. Glycerol can be converted to solketal, which can be used as a green fuel additive to enhance an octane or cetane number. Conversion of glycerol to solketal was conducted via acetalization reaction with acetone using amberlyst-15 as the catalyst. The objective of present study was to investigate the effect of some operation conditions on glycerol conversion. Furthermore, it also aimed to develop a kinetic model of solketal synthesis with amberlyst-15 resins. The experiment was conducted in a batch reactor, equipped with cooling water, thermometer, stirrer, and a water bath. The variables that have been investigated in the present work were reaction temperature, reactants molar ratio, catalyst loading, and stirrer speed for 3 hours of reaction time. Temperatures, reactants molar ratio, and stirrer speed appeared to have a significant impact on glycerol conversion, where the higher values led to higher conversion. On the other hand, in the presence of catalyst, the increase of catalyst loading has a less significant impact on glycerol conversion. The results showed that the highest glycerol conversion was 68.75%, which was obtained at 333 K, the reactant’s molar ratio was  4, the amount of catalyst was 1 wt%, and stirrer speed of 500 rpm. Based on the pseudo-homogeneous kinetic model, the resulting kinetic model suitable for this glycerol capitalization. The value of parameters k and Ea were 1.6135 108 min-1 and 62.226 kJ mol-1,respectively. The simulation model generally fits the experimental data reasonably well in the temperature range of 313-333 K.

Community supports for people affected by cancer

2013 ◽  
Author(s):  
Michael Jefford
Keyword(s):  
Clinical Setting ◽  
Health Care Professionals ◽  
Critical Role ◽  
Critical Issue ◽  
Care Needs ◽  
The Many ◽  
Additional Support ◽  
Community Supports

Chapter 11 considers the supportive care needs of people affected by cancer – not just those who are told that they have a cancer diagnosis, but also their family members and friends, who are also often profoundly affected. The critical role of health care professionals in meeting the needs of all people affected by cancer is underscored. The many and varied sources of additional support provided outside the clinical setting are then described. The review focuses upon the needs of adults with cancer, though many of the issues and examples are also applicable to children, adolescents, and young adults with cancer. A critical issue is how to best integrate clinical programmes with the variety of supports outside the clinical setting.

scholarly journals Critical Role of Virion-Associated Cholesterol and Sphingolipid in Hepatitis C Virus Infection

2008 ◽  
Vol 82 (12) ◽  
pp. 5715-5724 ◽  
Author(s):  
Hideki Aizaki ◽  
Kenichi Morikawa ◽  
Masayoshi Fukasawa ◽  
Hiromichi Hara ◽  
Yasushi Inoue ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Cell Attachment ◽  
Critical Role ◽  
Molar Ratio ◽  
Complete Life Cycle ◽  
Rna Accumulation ◽  
Hydrolysis Of ◽  
Hcv Structural Proteins

ABSTRACT In this study, we establish that cholesterol and sphingolipid associated with hepatitis C virus (HCV) particles are important for virion maturation and infectivity. In a recently developed culture system enabling study of the complete life cycle of HCV, mature virions were enriched with cholesterol as assessed by the molar ratio of cholesterol to phospholipid in virion and cell membranes. Depletion of cholesterol from the virus or hydrolysis of virion-associated sphingomyelin almost completely abolished HCV infectivity. Supplementation of cholesterol-depleted virus with exogenous cholesterol enhanced infectivity to a level equivalent to that of the untreated control. Cholesterol-depleted or sphingomyelin-hydrolyzed virus had markedly defective internalization, but no influence on cell attachment was observed. Significant portions of HCV structural proteins partitioned into cellular detergent-resistant, lipid-raft-like membranes. Combined with the observation that inhibitors of the sphingolipid biosynthetic pathway block virion production, but not RNA accumulation, in a JFH-1 isolate, our findings suggest that alteration of the lipid composition of HCV particles might be a useful approach in the design of anti-HCV therapy.

Optimized Enzymatic Production of Waste Oil to Biodiesel

2013 ◽  
Vol 291-294 ◽  
pp. 284-289
Author(s):  
Xue Lin Zhang ◽  
Jun Jun Li ◽  
Xiang Hua Tang ◽  
Zhen Rong Xie ◽  
Zun Xi Huang
Keyword(s):  
Response Surface Methodology ◽  
Experimental Designs ◽  
Biodiesel Production ◽  
Molar Ratio ◽  
Optimal Conditions ◽  
Optimum Conditions ◽  
Waste Oil ◽  
Reaction Parameters ◽  
Enzymatic Production ◽  
Oil Water

This study employed statistically based on experimental designs to optimize transesterification conditions for biodiesel production from waste oil via lipase-catalyzed in homoeothermy. Optimization of different reaction parameters were done by using response surface methodology. Results indicated optimum conditions including: alcohol to oil molar ratio 3:1, lipase concentration 58.38 U each gram of oil, water and n-hexane content were 24.59% and 13.28% respectively, reaction temperature at 20 °C , and reaction time for 24 h. Under these optimal conditions, 98.24% yield of biodiesel was obtained. This study will probably contribute to the development of continuous enzymatic processes, and maybe a suitable method for industrial production of biodiesel.

scholarly journals Oyster andPyramidellaShells as Heterogeneous Catalysts for the Microwave-Assisted Biodiesel Production fromJatropha curcasOil

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Achanai Buasri ◽  
Tidarat Rattanapan ◽  
Chalida Boonrin ◽  
Chosita Wechayan ◽  
Vorrada Loryuenyong
Keyword(s):  
Jatropha Curcas ◽  
Heterogeneous Catalysts ◽  
Biodiesel Production ◽  
Bet Surface Area ◽  
Molar Ratio ◽  
Catalyst Loading ◽  
X Ray ◽  
Microwave Assisted ◽  
Xrf Scanning ◽  
Waste Shell

Microwave-assisted biodiesel production via transesterification ofJatropha curcasoil with methanol using solid oxide catalyst derived from waste shells of oyster andPyramidellawas studied. The shells were calcined at 900°C for 2 h and calcium oxide (CaO) catalyst characterizations were carried out by X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscope (SEM), and the Brunauer-Emmett-Teller (BET) surface area measurements. The effects of reaction variables such as reaction time, microwave power, methanol/oil molar ratio, and catalyst loading on the yield of biodiesel were investigated. Reusability of waste shell catalyst was also examined. The results indicated that the economic and environmentally friendly catalysts derived from oyster andPyramidellashells showed good reusability and had high potential to be used as biodiesel production catalysts under microwave-assisted transesterification ofJatropha curcasoil with methanol.

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