Solvent Crystallization of Palm-Based Dihydroxystearic Acid

Palm based 9,lO-threo dihydroxystearic acid (DHSA) was produced from epoxidation of oleic acid with performic acid, followed by hydrolysis of the epoxide. It is widely used as ingredient in cosmetic industries. However, it is a requirement for low purity crude DHSA to undergo a purification stage in order to fulfil the stringent quality requirement in this field. Solvent crystallization has been employed with detailed examination to produce good quality crystallized product. The objective of this research work is to carry out a preliminary and detailed study on the solvent crystallization of palm based DHSA. Preliminary study was done using two different solvents, ethanol and hexane, at several concentratipns and cooling conditions. The chemical and physical product properties of the crystallized product are evaluated using gas chromatography (GC), crystal size distribution (CSD) and scanning electron microscopy (SEM). The preliminary studies suggested that crystallization of DHSA using ethanol has been successfully achieved and natural cooling mode gives better performance compared to rapid cooling mode, almost in all aspects. However, crystallization of DHSA using hexane as solvent was unable to shape DHSA into crystal. It produced bulk solid DHSA with low purity percentage (79%). Based on preliminary studies, an investigation on controlled cooling crystallization using a fabricated crystallizer has been conducted. This study focuses on various operating conditions, namely temperature (24"C, 26"C, 28"C), time (1 - 12 hours), seeding process (2.5, 5, lograms) and cooling modes (natural and controlled crystallization). Effect of these parameters on crystal size distribution (CSD), purity and yield of crystallized product has been examined. Quality and quantity of crystals produced via the controlled cooling crystallizer are greatly influenced by the operating temperature. Higher working temperature produced crystals with higher purity and larger average crystal size. However, the yield is lower. Controlled crystallization process results in a better crystal properties compared to natural cooling crystallization, generally in almost all aspects. Furthermore, the addition of DHSA seed into the solution could reduce the purity of product and at the same time, as it could retard the crystal growth

Production of biodiesel from used cooking oil (UCO) using ion exchange resins as catalysts

This study focuses on the development of novel two-stage esterification-transesterification synthesis of biodiesel from used cooking oil (UCO) using novel heterogeneous catalysts. The esterification of the UCO was investigated using three types of ion exchange resins catalysts including Purolite D5081, Purolite D5082 and Amberlyst 15. Of all the catalysts investigated, Purolite D5081 resin showed the best catalytic performance and was selected for further optimisation studies. From the optimisation study, it was found that the external and internal mass transfer resistance has negligible effect on the esterification reaction. At the optimum reaction conditions, Purolite D5081 achieved 92% conversion of FFA. During reusability study, the conversion of FFA dropped by 10% after each cycle and it was found that progressive pore blockage and sulphur leaching were dominant factors that decreased the catalytic performance of the Purolite D5081 catalyst. A kinetic modelling for FFA esterification was carried out using Purolite D5081 as a catalyst. Three types of kinetic models were investigated i.e. pseudo homogeneous (PH), Eley-Rideal (ER) and Langmuir-Hinshelwood-Hougen-Watson (LHHW). Experimental data obtained from the batch kinetic studies was successfully represented by the PH model and a good agreement between experimental and calculated values was obtained. The activation energy for esterification and hydrolysis reaction was found to be 53 and 107 kJ/moL. The transesterification of pre-treated cooking oil (P-UCO) was investigated using various types of heterogeneous catalysts including Purolite CT-122, Purolite CT-169, Purolite CT-175, Purolite CT-275, Purolite D5081, Diaion PA306s and Cs-supported heteropolyacids catalysts. Of all the catalysts investigated, Diaion PA306s catalyst showed the highest conversion of triglycerides and was selected for further optimisation studies. At the optimum reaction conditions, Diaion PA306s achieved ca. 75% of triglycerides conversion. During the reusability study, Diaion PA306s catalyst gave a similar conversion of triglycerides after being reused once. Therefore, it was concluded that the resin can be used several times without losing catalytic activity. Several purification methods have been investigated and dry washing method was chosen as the best alternative for biodiesel purification

Biodiesel in Holy Quran: Among The Review of The Arabic Lexicography and Modern Science

The Holy Qur’an is a miracle revealed to Prophet Muhammad, Sallallahu Alayhi Wa Salam, that not only discusses elements on beliefs but at the same time, it is compact with some absolutely amazing scientific facts. There are many verses that discuss the description of the scientific facts in the holy Quran. Among the scientific facts found in the holy Quran is the verse that deals with the concept of energy sources such as biodiesel which is found in Yas eenverse 80. However, the interpretation of this verse according to academicians of the past has been from a different perspective. Findings in the biodiesel field by modern scientists have opened a new chapter in the interpretation related to the biodiesel concept found in the holy Qur’an. This study will analyze the opinion of the Arab-Islamic scholars in the interpretation of this verse from the perspective of Islamic code and Arabic lexicography. Furthermore, this discussion will be conducted to examine the relationship of this verse with the concept of biodiesel from the perspective of modern science. The results of the experiments that have been conducted showing that the am ount of energy that results from the reaction of plants, solvents and catalysts to produce biodiesel which is one of the potential of alternative energy sources to replace conventional fuels. The formation of the chemical structure of biodiesel produced from the breakdown of triglyceride structure ( i.e oil from gree plants) that reacts with hydroxide ions and produce three molecules of fatty acid methyl esters FAME(i.e biodiesel ) and one molecule of glycerol . It shows that green elements found in plant s is an energy element . It is hoped that this study will open up new perspectives on the interpretation of the verse that relates to the concept of biodiesel in holy Quran based on scientific facts. Indirectly, it also proves that the holy Quran is the revelation of God and not the invention of Prophet Muhammad

Catalysis for CO2 conversion; perovskite based catalysts

CO2 conversion processes require the use of active catalysts due to the endothermicity of these reaction processes. The use of heterogeneous catalysts such as perovskites is gaining more attention due to their ease of separation, stability in handling, catalyst reuse and reproductively. Perovskite possesses wide industrial, scientific and commercial importance because of their cost effectiveness and stability in high temperature conditions while offering flexibility of its structures. CO2 is effective as a reagent for the conversion of hydrocarbons into more useful products like H2, syngas and liquid fuels. Researchers have focused extensively on CO2 reforming of methane (CRM) as the process mitigates two readily available greenhouse gases. However, the overall conversion in this process is dependent on factors such as amount/ratio of reactants, reaction conditions and type of catalysts used. Majorly, perovskites have been applied as catalysts for CO2 reforming because they possess highly mobile oxygen molecules. This property is essential to suppress the formation of carbon during the reaction. Moreover, its stable nature in a reducing environment gives it an edge over other types of catalysts used for CO2 reforming. Hence, the focus of this chapter is on the role played by perovskites as catalysts in the CO2 reforming of methane reaction process

Characterization of Ag-promoted Ni/SiO2 Catalysts for Syngas Production via Carbon Dioxide (CO2) Dry Reforming of Glycerol

The carbon dioxide (CO2) dry reforming of glycerol for syngas production is one of the promising ways to benefit the oversupply crisis of glycerol worldwide. It is an attractive process as it converts carbon dioxide, a greenhouse gas into a synthesis gas and simultaneously removed from the carbon biosphere cycle. In this study, the glycerol dry reforming was carried out using Silver (Ag) promoted Nickel (Ni) based catalysts supported on silicon oxide (SiO2). The catalysts were prepared through wet impregnation method and characterized by using Bruanaer-Emmett-Teller (BET) surface area, Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and Thermo Gravimetric (TGA) analysis. The experiment was conducted in a tubular reactor which condition fixed at 973 K and CO2: glycerol ratio of 1, under atmospheric pressure. It was found that the main gaseous products are H₂, CO and CH4 with H₂:CO < 1.0. From the reaction study, Ag(5)NiSiO2 results in highest glycerol conversion and hydrogen yield, accounted for 32.6% and 27.4%, respectively

Effective combination of metal-support for bimetallic catalysts system in ethanol and glycerol reforming: A review

The reliance on fossil fuels to meet the world energy demands throughout these years has led to future insecurity of non-renewable energy sources. Thus, the necessity to provide the energy requirement as we are moving forward falls into renewable and environmentally friendly options. Syngas or hydrogen-based energy rise as potential alternatives credited to high efficiency and clean emissions [1]. In addition, production of hydrogen from biomass keep gaining attention from industrial and academic expertise especially for the reforming technologies. Ethanol and glycerol are emerged as alternatives feedstock for hydrogen production in the last several years due to ethanol is a high hydrogen-containing compound and can be easily derived from renewable biomass resources wheat, sugarcane and organic fractions from forestry residue or municipal [2,3] whereas, glycerol is by product of biodiesel that expected to surplus in amount in near future [4]. Additionally, there are many routes that led to production of syngas or hydrogen namely, steam reforming, partial oxidation, pyrolysis, bi-reforming, CO2 reforming, autothermal reforming, aqueous phase reforming. Ni-based catalysts widely employed in the aforementioned reforming process attributed to its affordable cost compared to noble metals, strong capability of rupturing C-C and C-O bonds and high availability [5]. Nevertheless, Ni-based catalysts tend to deactivate due to carbon formation and thermal Ni sintering [6]. The introduction of bimetallic or polymetallic is one of the significant solutions to reduce carbon formation and catalysts deactivation in reforming process since it can produce more stable catalysts from interaction between two metals [7]. Thus, the aim of this review is to emphasize the application of bimetallic catalysts in glycerol and ethanol reforming based on metal combination. The combination of transition metal will be included the effect of actives site and carbon formation, noble metal pairing will be focused on metal dispersions and transition-noble metal combination will be explained the effect of reduction rate and redox properties as well as the role of support. In addition, the brief explanation of reforming technologies and the summarized findings of structure, classification along with catalysts preparation method will be described in this review

Characterization of Ag-promoted Ni/SiO2 Catalysts for Syngas Production via Carbon Dioxide (CO2) Dry Reforming of Glycerol

The carbon dioxide (CO2) dry reforming of glycerol for syngas production is one of the promising ways to benefit the oversupply crisis of glycerol worldwide. It is an attractive process as it converts carbon dioxide, a greenhouse gas into a synthesis gas and simultaneously removed from the carbon biosphere cycle. In this study, the glycerol dry reforming was carried out using Silver (Ag) promoted Nickel (Ni) based catalysts supported on silicon oxide (SiO2) i.e. Ag-Ni/SiO2. The catalysts were prepared through wet impregnation method and characterized by using Brunauer-Emmett-Teller (BET) surface area, Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and Thermo Gravimetric (TGA) analysis. The experiment was conducted in a tubular reactor which condition fixed at 973 K and CO2:glycerol molar ratio of 1, under atmospheric pressure. It was found that the main gaseous products are H₂, CO and CH4 with H₂:CO molar ratio < 1.0. From the reaction study, Ag(5)-Ni/SiO2 results in highest glycerol conversion and hydrogen yield, accounted for 32.6% and 27.4%, respectively.

Two-Stage Conversion of Used Cooking Oil to Biodiesel Using Ion Exchange Resins as Catalysts

This study focuses on the development of a novel two-stage (esterification–-transesterification) synthesis of biodiesel from used cooking oil (UCO) using ion exchange resins as catalysts. Ester-ification of the UCO has been conducted using various types of ion exchange resin catalysts. Purolite D5081, a hyper cross-linked resin, showed the best catalytic performance among all the catalysts investigated, with 92% of free fatty acid (FFA) conversion. The transesterification of pre-treated used cooking oil (P-UCO) was carried out sequentially using several acidic and basic ion exchange resin catalysts. In the screening process, the Diaion PA306s catalyst showed the best catalytic performance and was selected for the optimisation study. A tTriglycerides conversion of ca. 75% was recorded at the optimum reaction conditions (9% (w/w) catalyst loading, 328 K reac-tion temperature, 18:1 methanol to P-UCO feed mole ratio, and 350 rpm stirring speed). Fur-thermore, the reusability study of the Diaion PA306s catalyst gave a similar triglycerides conver-sion after a couple of cycles without losing its catalytic activity. A dry purification technique was found to give the lowest percentage of glycerides and glycerine content and, therefore, was chosen as the best biodiesel purification route

Two-Stage Conversion of Used Cooking Oil to Biodiesel Using Ion Exchange Resins as Catalysts

This study focuses on the development of a novel two-stage (esterification–transesterification) synthesis of biodiesel from used cooking oil (UCO) using ion exchange resins as catalysts. Esterification of the UCO has been conducted using various types of ion exchange resin catalysts. Purolite D5081, a hyper cross-linked resin, showed the best catalytic performance among all the catalysts investigated, with 92% of free fatty acid (FFA) conversion. The transesterification of pre-treated used cooking oil (P-UCO) was carried out sequentially using several acidic and basic ion exchange resin catalysts. In the screening process, the Diaion PA306s catalyst showed the best catalytic performance and was selected for the optimisation study. A triglyceride conversion of ca. 75% was recorded at the optimum reaction conditions (9% (w/w) catalyst loading, 328 K reaction temperature, 18:1 methanol to P-UCO feed mole ratio, and 350 rpm stirring speed). Furthermore, the reusability study of the Diaion PA306s catalyst gave a similar triglyceride conversion after a couple of cycles without losing its catalytic activity. A dry purification technique was found to give the lowest percentage of glycerides and glycerine content and, therefore, was chosen as the best biodiesel purification route

Esterification of Free Fatty Acid in Used Cooking Oil Using Gelular Exchange Resin as Catalysts

The esterification of free fatty acids (FFA) in used cooking oil was investigated using gelular ion exchange resins, SK104H and SK1BH catalysts. Characterization methods such as Fourier transform-infra red (FT-IR) spectroscopy, particle size distribution (PSD), scanning electron microscopy (SEM), elemental analysis (CHNS) and acid capacity analysis were conducted to determine the physicochemical properties of the catalysts. These catalysts were then subjected to a screening study to select the best performance catalyst, which further subjected to esterification reaction using one-variable-at-a-time (OVAAT) method. Using OVAAT method, the effect of mass transfer resistance, catalyst loading, reaction temperature and methanol to oil mass ratio were studied to optimize esterification reaction conditions. The conversion of FFA in the used cooking oil was successfully achieved 88% under optimal conditions of 18:1 methanol to oil mass ratio, reaction temperature of 60oC, catalyst loading of 3.0 wt. % and 300 rpm of stirring speed. Excellence catalytic performance may attributed to the smallest average particle size, high sulfur content and high acid capacity value of SK104H, resulting high conversion of FFA