METHANOLYSIS AND ETHANOLYSIS OF ANIMAL FATS: A COMPARATIVE STUDY OF THE INFLUENCE OF ALCOHOLS

Biodiesel from animal fats with methanol and ethanol was produced in the presence of sodium methoxide and sodium ethoxide as catalysts. Two samples of pork fats and one natural beef tallow were directly transesterified with a good final product yield: 87.7, 86.7 and 86.3% for methanolysis, and 78.4, 82.6 and 82.7% for ethanolysis, respectively. Methyl ester content was also determined, being higher than 96.5 mass% for all the samples prepared. The presence of natural C17:0 in animal fats makes it necessary to correct the method pro¬posed in the standard EN 14103 (2003). Biodiesel density at 15 C of the samples was between 870 and 876 kg/m3, within the acceptance range of standard EN 14214, and the dynamic viscosity at 40 °C of the produced biodiesels was in the range of 4.5 to 5.16 mm2/s, also fulfilling requirements of EN 14214 standard. The iodine value is much lower than the superior limit established by EN 14214 standard but oxidation stability (OSI) is lower than the required limit, 6 h, of the standard, which can be attributed to the lack of natural antioxidants in tallows

Hydrothermal treatment of bio-oil for the production of biodiesel antioxidants

INTRODUCTION Fuel consumption is inevitable for industrial development and growth of any country. In the last years, diesel fuels have gained an increasingly important role in the transportation sector. However, the rapid depletion of crude oil resources, as well as the worldwide concern about the environmental damage related to the increase in the emissions of carbon dioxide and other pollutants, has led to an increasing awareness about the development and use of renewable fuels. In this context, biodiesel appears as a good alternative to fossil diesel because of its renewable and biodegradable character, also being a non-toxic and clean fuel that can be used in compression ignitions engines with little or no modification [1]. Biodiesel is largely composed of a mixture of long chain fatty acid monoalkyl esters (FAME) and can be commercially produced through the transesterification reaction of natural triglycerides with a short chain alcohol. Although the technology for converting edible oils such as sunflower oil, palm oil, soybean oil, coconut oil or rapeseed oil to biodiesel has been well established [2, 3], this practice is gaining serious global concern on preserving food security of the planet. Therefore, there is a marked trend towards abolition of the use of edible oils for fuel production, encouraging the use of biofuels derived from non-edible ligno-cellulosic plants and wastes [4]. Please click Additional Files below to see the full abstract

Antioxidant additives produced from Argan shell lignin depolymerization

The present work summarizes the results of an experimental study focused on producing antioxidant additives for biofuels from argan shell lignin. The generation of this waste has noticeably increased in specific regions of Morocco as a result of the upward trend in the production of argan oil. Lignin extracted from argan shells via a semi-chemical pulping process was depolymerized under hydrothermal conditions in a stirred autoclave reactor at a temperature range of 250-350 °C. Lignin conversion to phenolic compounds was conducted in subcritical water together with different reaction medium (H2, CO2, and HCOOH). The organic fraction in the aqueous liquid product was extracted and blended with biodiesel at a dosage of 1 wt % to evaluate its antioxidant potential. According to the obtained results, the biodiesel oxidation stability time was drastically improved up to 400%. The depolymerization temperature was observed as a critical factor in the antioxidant potential of the additives, showing a maximum value at 300 °C, regardless of the reaction medium. An extensive characterization of the produced additives was performed. The phenolic monomers present in the produced additives were identified using gas chromatography-mass spectrometry, finding a notable presence of catechol, especially in the additives obtained at 300 °C, which led to the best results of biodiesel oxidation stability. Gel permeation chromatography analyses of the additives also showed a well dissolution of relatively big molecules (up to 7000 Da) in biodiesel. More efforts are required to verify the actual antioxidant potential of these types of molecules

Hydrogen and CNT production by methane cracking using Ni–Cu and Co–Cu catalysts supported on argan-derived carbon

The 21st century arrived with global growth of energy demand caused by population and standard of living increases. In this context, a suitable alternative to produce COx-free H2 is the catalytic decomposition of methane (CDM), which also allows for obtaining high-value-added carbonaceous nanomaterials (CNMs), such as carbon nanotubes (CNTs). This work presents the results obtained in the co-production of COx-free hydrogen and CNTs by CDM using Ni–Cu and Co–Cu catalysts supported on carbon derived from Argan (Argania spinosa) shell (ArDC). The results show that the operation at 900 °C and a feed-ratio CH4:H2 = 2 with the Ni–Cu/ArDC catalyst is the most active, producing 3.7 gC/gmetal after 2 h of reaction (equivalent to average hydrogen productivity of 0.61 g H2/gmetal∙h). The lower productivity of the Co–Cu/ArDC catalyst (1.4 gC/gmetal) could be caused by the higher proportion of small metallic NPs (<5 nm) that remain confined inside the micropores of the carbonaceous support, hindering the formation and growth of the CNTs. The TEM and Raman results indicate that the Co–Cu catalyst is able to selectively produce CNTs of high quality at temperatures below 850 °C, attaining the best results at 800 °C. The results obtained in this work also show the elevated potential of Argan residues, as a representative of other lignocellulosic raw materials, in the development of carbonaceous materials and nanomaterials of high added-value

Antioxidants for biodiesel: Additives prepared from extracted fractions of bio-oil

Unlike petroleum diesel, the chemical structure of biodiesel makes it prone to oxidation during long-term storage, thus involving fuel quality deterioration. Therefore, the addition of antioxidants is usually required to meet the quality standards for biodiesel commercialization. Synthetic sterically-hindered phenols have been usually employed for this purpose as free radical scavenging antioxidants. However, naturally occurring phenolics are also available, for example, in the bio-oil produced in the pyrolysis of lignocellulosic biomass. In this work, the antioxidant potential of extracted fractions of lignocellulosic bio-oil has been evaluated. Different organic solvents were tested as extraction agents, acetate esters being the best ones for incorporating bio-oil antioxidant compounds into biodiesel. In the best case, the incorporation of a small concentration of bio-oil compounds (< 4 wt.%) led to an improvement of the biodiesel oxidation stability of 475% which, in our case, was enough to meet the European standard requirement

The influence of AC and Ni/AC catalyst in the antioxidant additives production from argan shells lignin

In this work, the production of antioxidant additives via hydrothermal treatment of lignin from argan nutshells (agricultural waste) was evaluated. Specifically, the effect of using a catalyst supported on activated carbon which had been prepared from the same waste (argan nutshells) has been studied

Antiferromagnetic single-chain magnet slow relaxation in the {Tb(α-fur)3}n polymer with non-Kramers ions

We report the synthesis, crystal structure and magnetic properties of a new molecular complex based on a Tb(iii) ion supported by 2-furancarboxylic molecules: {Tb(α-fur)(HO)} (α-fur = CHOCOO). Two slightly different Tb sites (A and B) exist depending on the position of one of the dangling ligands. Ab initio calculations predict that, for both sites, the magnetic ground state is highly anisotropic (g∗ = 17.8) and consists of a quasi-doublet with a small gap, well isolated from the next excited state. The α-fur ligand forms 1D polymeric chains of Tb ions of the same type (either A or B) running along the c-axis. The crystal structure is formed by the supramolecular stacking along the a-axis of 2D layers containing parallel chains of the same type. Static magnetization and heat capacity measurements show that, magnetically, the system can be modeled as an ensemble of Ising chains of non-Kramers Tb ions with effective spin S∗ = 1/2, antiferromagnetically (AF) coupled by a weak intrachain interaction (J∗/k = -0.135 K). At very low temperatures, the static susceptibility reflects the presence of a 2-4% concentration of defects in the chains. Ac susceptibility measurements at H = 0 performed down to mK temperatures have enabled us to observe the slow relaxation of magnetization through two different pathways. They are assigned to Single-Chain-Magnet (SCM) behavior in two different types of AF chains (A and B), triggered by the existence of defects breaking the chains into segments with short-range order. At temperatures below 0.1 K this mechanism is replaced by individual relaxation of the ions through direct processes. Under the application of a magnetic field the system slowly relaxes by two distinct direct processes, strongly affected by a phonon bottleneck effect.This work has been financed by MECOM Projects MAT11/23791 and MAT11/27233-C02-02, MAT2015-68204-R, MAT2014-53921-R, DGA IMANA E34 and MOLCHIP E98 Projects. Consolider Nanoselect (CSD2007-00041) and by a grant of the Ministry of National Education, CNCS – UEFISCDI, project number PN-II-ID-PCE-2012-4-0261. D. P. thanks the Alexander von Humboldt (AvH) Foundation for financial support.Peer Reviewe

Predicción de la propiedad del número de cetano con modelos matemáticos

Se ha desarrollado un modelo basado en m&eacute;todos de contribuci&oacute;n de grupos funcionales para la predicci&oacute;n de la propiedad n&uacute;mero de cetano, caracter&iacute;stica del biodiesel. Se observa un alto grado de ajuste entre los datos te&oacute;ricos y los experimentales con un R2 de 0.93 permitiendo predecir dicha propiedad sin necesidad de un arduo trabajo experimental

CO2 activation of char from argan nutshells pyrolysis a preliminary study

CO2 physical activation was performed to produce activated carbons from pyrolysis char. The process was fed by char produced in the pyrolysis of argan nutshells. This unexplored feedstock is a residue of argan oil production. This preliminary study showed that the activated carbons obtained in this process are characterized by a large surface area and a great capacity to retain contaminants