Synthesis of Fatty Alcohol-Based Phosphate Esters

Fatty chemicals based on edible and inedible tallow and a variety of vegetable oils have wide use in plastics industry. At present, there are some limitation and economic competition between plastics additives based on fats and oils and those from fossil fuels (crude oil and natural gas). The large growth of palm oil production in Malaysia and the rapid expansion of oleochemical production facilities in Malaysia imply strong growth for these chemicals in plastics application in the recent years. Oleochemicals has been reported being large used as emulsifiers and stabilizer in polymerization, as auxiliarities for processing and as structural materials in plastics industry. A preliminary study carried out has shown the compatibility between inorganic fillers (calcium carbonate, CaCO3) and the polyvinylchloride resins (PVC) can be improved by adding oleochemical-based surfactant to the CaCO3, prior to its mixing with the plastic resins. A more homogeneous mixture was obtained, thus better PVC plastics was produced. This research was therefore undertaken to synthesize fatty alcohol-based phosphate ester using fatty alcohol as the starting material to be used as the coupling agent for the CaCO3 and plastics resins. In this study, the syntheses were carried out in three different routes and each route were divided into three steps. Fatty alcohol-based phosphate esters with diphosphate ester functional group were prepared by reacting a diol with phosphorus oxychloride (POCl3) and then followed by addition of long-chained fatty alcohol. In route one, C16-fatty alcohol was used in the synthesis. The optimized reaction temperatures for each step of reaction in this route were 20 °C, 35 ºC and 70 ºC respectively. The reaction duration of each step was about 3 hours. Excess of phosphorus oxychloride (2.5 mole) was used and 0.1% (w/w) of catalyst tetrabutyl orthotitanate (based on the weight of fatty alcohol) was employed in the synthesis. The percentage yield of the final product obtained from the titration of acidic solution (HCl gas in distilled water) with NaOH solution was about 60 %. From the GC, GC-MS, LC and LC-MS analyses, monophosphate ester (dipropyl heptadecyl phosphate ester) with the percentage of about 4.8% was obtained. While, the major compounds obtained were 1,6-dichlorohexane and 1-chlorohexadecane with the total percentage ~ 70%. In route two and three, the reactions were carried out under the reaction temperature of 20 °C, 90 ºC and 90 ºC for each step of the reaction respectively. The optimized reaction duration for each step was 2 hours, 2 hours and 1 hour respectively. In these syntheses, excess of phosphorus oxychloride (2.5 mole) was also used but no catalyst was applied in the reaction. The fatty alcohol used in route three was different with route one and two, whereby C18-fatty alcohol was used. The percentage yield of the final product obtained under these conditions was about 10-40% (by titration method). From the GC-MS and LC-MS analyses, the major compounds obtained from the synthesis were also 1,6-dichlorohexane and 1-chlorohexadecane which gave a total yield of ~74.06%. The phosphate ester obtained in this synthesis was a diphosphate ester (trihexadecyl hexyl diphosphate ester) with the percentage of about ~ 2.5%. Finally the products obtained were applied in PVC compounding. Some basic formulations were prepared, which comprised the synthesized phosphate ester (PE/T10), PVC resin, plasticizer (DOP), stabilizer (TBLS) and calcium carbonate as filler (CaCO3). The mixture of these polymers and additives was blended at 170 ºC with a mixing speed of 70 r.p.m. The homogenized plasticized mixture was then compressed on a hot press at 170 ºC for 10 min. Based on the tensile strength results, a slight decreased in the tensile properties was observed when the ester sample was added into the PVC compounding which could be due to the presence of chlorinated compound present as indicated by the analyses. The chlorinated compound may have reacted with the filler (CaCO3) during the PVC compounding process and thus causing the decreased in tensile strength of the plastic sheets. However, in general, the physical appearance of the PVC sheet could be improved by the synthesized phosphate ester (PE/T10) after further dried with anhydrous calcium sulphate whereby a smooth surface was observed compared to the PVC sheet without added of phosphate ester (PE/T10)

Study of glycerol electrochemical conversion into addes-value compounds

The price of crude glycerol has significantly decreased worldwide because of its oversupply. Many chemical and biological processes have been proposed to transform glycerol into numerous value-added products, such as glycolic acid, 1,3-propanediol (1,3-PDO), 1,2-propanediol (1,2-PDO), glyceric acid, and lactic acid. However, these processes suffer from several drawbacks, including high production cost. Therefore, in this study, a simple and robust electrochemical synthesiswas developed to convert glycerol into various value-added compounds. This study reports for the first time the use of Amberlyst-15 as a reaction mediumand redox catalyst for electrochemical conversion of glycerol. In the first part, the electrochemical performance of Amberlyst-15 over platinum (Pt)electrode was compared with that of conventional acidic (H2SO4) and alkaline (NaOH) media. Other parameters such as reaction temperature [room temperature (27°C) to 80 °C] and applied current (1.0 A to 3.0 A) were also examined. Under the optimized experimental condition, this novel electrocatalytic method successfully converted glycerol into glycolic acid after 8 h of electrolysis, with a yield of 45% and selectivity of 65%, as well as to glyceric acid after 3 h of electrolysis, with a yield of 27% and selectivity of 38%. In the second part of this study, two types of cathode electrodes, namely, activated carbon composite(ACC) and carbon black diamond (CBD) electrodes, were used in electrochemical conversion of glycerol. To the best of our knowledge, electrochemical studies of glycerol conversion using these electrodes have not been reported yet. Glycerol was also successfully reduced to lactic acid, 1,2-PDO, and 1,3-PDO, in addition to oxidation compounds (e.g. glycolic acid). Three operating parameters, namely, catalyst amount (6.4% to 12.8% w/v), reaction temperature [room temperature (27 °C) to 80 °C], and applied current (1.0 A to 3.0 A), were tested. In the presence of 9.6% w/v Amberlyst-15 at 2.0 A and 80 °C, the selectivity of glycolic acid can reach 72% and 68% (with yield of 66% and 58%) for ACC and CBD electrodes, respectively. Lactic acid was obtained as the second largest compound, withselectivity of 16% and yield of 15% for the ACC electrode and 27% selectivity and 21% yield for the CBD electrode. Finally, electro-oxidation and electroreduction of glycerol were performed in a two-compartment cell separated by a cation exchange membrane (Nafion 117). This study only focused on the electroreduction region. Three cathode electrodes (Pt, ACC, and CBD) were evaluated under the following conditions: 2.0 A, 80 °C, and 9.6% w/v Amberlyst-15. ACC demonstrated excellent performance in the electroreduction study and successfully reduced glycerol to 1,2-PDO, with a high selectivity of 85%. The selectivity of 1,2-PDO on Pt and CBD was 61% and 68%, respectively. Acetol and diethylene glycol were also obtained. The reaction mechanisms underlying the formation of these products are then proposed

Production of lactic acid and glycolic acid in one-pot electrochemical cell

In recent years, due to the oversupply of glycerol globally, its price has dropped dramatically or become valueless. The aim of this study is to convert glycerol into high value-added compounds such as glycolic acid and lactic acid in one-pot electrochemical cell. The electrochemical process was carried out over platinum (as anode electrode) and activated carbon composite (as cathode electrode), with amberlyst-15 as reaction catalyst. The results obtained have proven that this simple method is applicable to produce glycolic acid and lactic acid in one step electrochemical process with a total product yield above 70 %. Finally, the overview reaction mechanism to the formation of these products was proposed. Please click Additional Files below to see the full abstract

Selective Electrochemical Conversion of Glycerol to Glycolic Acid and Lactic Acid on a Mixed Carbon-Black Activated Carbon Electrode in a Single Compartment Electrochemical Cell

In recent years, the rapid swift increase in world biodiesel production has caused an oversupply of its by-product, glycerol. Therefore, extensive research is done worldwide to convert glycerol into numerous high added-value chemicals i.e., glyceric acid, 1,2-propanediol, acrolein, glycerol carbonate, dihydroxyacetone, etc. Hydroxyl acids, glycolic acid and lactic acid, which comprise of carboxyl and alcohol functional groups, are the focus of this study. They are chemicals that are commonly found in the cosmetic industry as an antioxidant or exfoliator and a chemical source of emulsifier in the food industry, respectively. The aim of this study is to selectively convert glycerol into these acids in a single compartment electrochemical cell. For the first time, electrochemical conversion was performed on the mixed carbon-black activated carbon composite (CBAC) with Amberlyst-15 as acid catalyst. To the best of our knowledge, conversion of glycerol to glycolic and lactic acids via electrochemical studies using this electrode has not been reported yet. Two operating parameters i.e., catalyst dosage (6.4–12.8% w/v) and reaction temperature [room temperature (300 K) to 353 K] were tested. At 353 K, the selectivity of glycolic acid can reach up to 72% (with a yield of 66%), using 9.6% w/v catalyst. Under the same temperature, lactic acid achieved its highest selectivity (20.7%) and yield (18.6%) at low catalyst dosage, 6.4% w/v

A review of recent progress on electrocatalysts toward efficient glycerol electrooxidation

Glycerol electrooxidation has attracted immense attention due to the economic advantage it could add to biodiesel production. One of the significant challenges for the industrial development of glycerol electrooxidation process is the search for a suitable electrocatalyst that is sustainable, cost effective, and tolerant to carbonaceous species, results in high performance, and is capable of replacing the conventional Pt/C catalyst. We review suitable, sustainable, and inexpensive alternative electrocatalysts with enhanced activity, selectivity, and durability, ensuring the economic viability of the glycerol electrooxidation process. The alternatives discussed here include Pd-based, Au-based, Ni-based, and Ag-based catalysts, as well as the combination of two or three of these metals. Also discussed here are the prospective materials that are yet to be explored for glycerol oxidation but are reported to be bifunctional (being capable of both anodic and cathodic reaction). These include heteroatom-doped metal-free electrocatalysts, which are carbon materials doped with one or two heteroatoms (N, B, S, P, F, I, Br, Cl), and heteroatom-doped nonprecious transition metals. Rational design of these materials can produce electrocatalysts with activity comparable to that of Pt/C catalysts. The takeaway from this review is that it provides an insight into further study and engineering applications on the efficient and cost-effective conversion of glycerol to value-added chemicals

Investigating the electrocatalytic oxidation of glycerol on simultaneous nitrogen- and fluorine-doped on activated carbon black composite

To develop non-metallic electrocatalyst for glycerol electrooxidation, simultaneous co-doping of nitrogen and fluorine into activated carbon black (ACB) composite was explored to investigate the physical and electrochemical characteristics. The ACB was prepared by mixing activated carbon and carbon black. The N and F were incorporated using aniline and polytetrafluoroethylene as the precursors. The morphologies of the prepared samples were analyzed and the electrochemical behavior, as well as the electrocatalytic performance, was investigated in acid and alkaline environment. Porosity analysis shows that 20% N and F co-doped ACB (ACB-N2F2) reduced the surface area (491.64 m2 g−1) and increased the electroactive surface area, which could contribute to faster mass transport and electron transfer process to enhance the catalytic activity the electrode. The doping defect also reduced the charge transfer resistance, which could increase the spin densities and maximize charge re-distribution to generate more electroactive surface. The electrodes N-doped ACB (ACB-N2) and ACB-N2F2 exhibited

Correction to: Thermal decomposition of rice husk: a comprehensive artificial intelligence predictive model

Unfortunately, in the original publication of the article the third author name was misspelled as Faisal Abnisal. The corrected author name should read as “Faisal Abnisa”. The affiliation of third author was incorrectly published. The corrected affiliation is given below

Thermal decomposition of rice husk: a comprehensive artificial intelligence predictive model

This study explored the predictive modelling of the pyrolysis of rice husk to determine the thermal degradation mechanism of rice husk. The study can ensure proper modelling and design of the system, towards optimising the industrial processes. The pyrolysis of rice husk was studied at 10, 15 and 20 °C min−1 heating rates in the presence of nitrogen using thermogravimetric analysis technique between room temperature and 800 °C. The thermal decomposition shows the presence of hemicellulose and some part of cellulose at 225–337 °C, the remaining cellulose and some part of lignin were degraded at 332–380 °C, and lignin was degraded completely at 480 °C. The predictive capability of artificial neural network model was studied using different architecture by varying the number of hidden neurone node, learning algorithm, hidden and output layer transfer functions. The residual mass, initial degradation temperature and thermal degradation rate at the end of the experiment increased with an increase in the heating rate. Levenberg– Marquardt algorithm performed better than scaled conjugate gradient learning algorithm. This result shows that rice husk degradation is best described using nonlinear model rather than linear model. For hidden and output layer transfer functions, ‘log-sigmoid and tan-sigmoid', and ‘tansigmoid and tan-sigmoid' transfer functions showed remarkable results based on the coefficient of determination and root mean square error values. The accuracy of the results increases with an increasing number of hidden neurone. This result validates the suitability of an artificial neural network model in predicting the devolatilisation behaviour of biomass

Study of glycerol electrochemical conversion into added-value compounds / Lee Ching Shya

The price of crude glycerol has significantly decreased worldwide because of its oversupply. Many chemical and biological processes have been proposed to transform glycerol into numerous added-value products, such as glycolic acid, 1,3-propanediol (1,3-PDO), 1,2-propanediol (1,2-PDO), glyceric acid, and lactic acid. However, these processes suffer several drawbacks, including high production cost. Therefore, in this study, a simple and robust electrochemical synthesis was developed to convert glycerol into various added-value compounds. This study reports for the first time the use of Amberlyst-15 as a reaction medium and redox catalyst for electrochemical conversion of glycerol. In the first part, the electrochemical performance of Amberlyst-15 over platinum (Pt) electrode was compared with that of conventional acidic (H2SO4) and alkaline (NaOH) media. Other parameters such as reaction temperature [room temperature (27 °C) to 80 °C] and applied current (1.0 A to 3.0 A) were also examined. Under the optimized experimental condition, this novel electrocatalytic method successfully converted glycerol into glycolic acid after 8 h of electrolysis, with a yield of 45% and selectivity of 65%, as well as to glyceric acid after 3 h of electrolysis, with a yield of 27% and selectivity of 38%. In the second part of this study, two types of cathode electrodes, namely, activated carbon composite (ACC) and carbon black diamond (CBD) electrodes, were used in electrochemical conversion of glycerol. To the best of our knowledge, electrochemical studies of glycerol conversion using these electrodes have not been reported yet. Glycerol was also successfully reduced to lactic acid, 1,2-PDO, and 1,3-PDO, in addition to oxidation compounds (e.g. glycolic acid). Three operating parameters, namely, catalyst amount (6.4% to 12.8% w/v), reaction temperature [room temperature (27 °C) to 80 °C], and applied current (1.0 A to 3.0 A), were tested. In the presence of 9.6% w/v Amberlyst-15 at 2.0 A and 80 °C, the selectivity of glycolic acid can reach 72% and 68% (with yield of 66% and 58%) for ACC and CBD electrodes, respectively. Lactic acid was obtained as the second largest compound, with selectivity of 16% and yield of 15% for the ACC electrode and 27% selectivity and 21% yield for the CBD electrode. Finally, electro-oxidation and electroreduction of glycerol were performed in a two-compartment cell separated by a cation exchange membrane (Nafion 117). This study only focused on the electroreduction region. Three cathode electrodes (Pt, ACC, and CBD) were evaluated under the following conditions: 2.0 A, 80 °C, and 9.6% w/v Amberlyst-15. ACC demonstrated excellent performance in the electroreduction study and successfully reduced glycerol to 1,2-PDO, with a high selectivity of 85%. The selectivity of 1,2-PDO on Pt and CBD was 61% and 68%, respectively. Acetol and diethylene glycol were also obtained. The reaction mechanisms underlying the formation of these products are then proposed

Étude de la conversion électrochimique du glycérol en différents composés à haute valeur ajoutée

Au cours des dernières années, la production excédentaire et sans cesse croissante de bioglycérol a provoqué une chute spectaculaire de son prix. Au cours des dernières années, un grand nombre de processus chimiques et biologiques ont été élaborés pour transformer le bioglycérol en divers produits à haute valeur ajoutée, tels que la dihydroxyacétone, l'acide glycolique, le 1,3-propanediol (1,3-PDO), 1,2-propanediol (1,2-PDO), l'acide glycérique, l'acide lactique, le carbonate de glycérol etc. Malheureusement, ces procédés souffrent de nombreux inconvénients comme par exemple, un coût élevé de production. Par conséquent, dans cette étude, une synthèse simple et robuste, basée sur un processus électrochimique a été introduite afin de convertir le bioglycérol en une grande variété de composés à haute valeur ajoutée. Cette étude rapporte pour la première fois l'utilisation de la résine Amberlyst-15 comme milieu réactionnel et comme catalyseur d'oxydo-réduction pour la conversion électrochimique du glycérol. La performance électrochimique du système composé par la résine Amberlyst-15 et l’électrode au platine (Pt), a été comparée à celle utilisant un milieu électrolytique conventionnel acide (H2SO4) ou alcalin (NaOH). D'autres paramètres tels que la température de réaction (température ambiante à 80 °C) et l’intensité du courant appliqué (1,0 A à 3,0 A) ont également été examinés. Dans les conditions expérimentales optimales, ce nouveau procédé électrocatalytique permet de convertir le glycérol, soit en acide glycolique, avec un rendement de 45% et une sélectivité élevée de 65%, soit en acide glycérique, avec un rendement de 27% et une sélectivité de 38%. D’autre part, deux autres électrodes ont été préparées et testées dans la réaction de transformation du glycérol : une électrode au charbon actif (ACC) et une électrode composite au noir de carbone et diamant CBD). A notre connaissance, il n’existe pas dans la littérature d’étude de transformation électrochimique du glycérol utilisant ce type d’électrodes. Dans ce travail, nous avons montré que le glycérol peut être oxydé en divers composés d’oxydation mais peut également être réduit avec succès en acide lactique,1,2-PDO et 1,3-PDO. Trois paramètres de fonctionnement, tels que la quantité de catalyseur (6.4 -12.8% w/v), la température de réaction [température ambiante (27°C) à 80 °C] et l’intensité du courant appliqué (1,0 A à 3,0 A), ont été testés. L'étude a révélé que, pour une quantité de catalyseur 9.6% w/v Amberlyst-15, un courant de 2,0 A et une température de 80 °C, la sélectivité en acide glycolique peut atteindre jusqu'à 72% et 68% (avec un rendement de 66% et 58%) en utilisant respectivement l’électrode ACC et l’électrode CBD. L'acide lactique a aussi été obtenu avec une sélectivité de 16% et un rendement de 15% en utilisant l’électrode ACC et une sélectivité de 27% pour un rendement de 21% dans le cas de l'électrode CBD. Enfin, l'électrooxydation et l'électro-réduction du glycérol a été effectuée dans une cellule à deux compartiments séparés par une membrane échangeuse de cations (Nafion 117). L’étude s’est focalisée sur l’électro-réduction. Trois cathodes (Pt, ACC et CDB) ont été évaluées dans les conditions suivantes : 2.0 A, 80 °C et 9.6% w/v Amberlyst-15. Les trois électrodes ont permis de réduire le glycérol en 1,2-PDO. Nous avons obtenu une sélectivité de 61% avec l’électrode au Pt et une sélectivité de 68% avec L’électrode CBD. En fait, c’est l’électrode ACC qui a démontré les meilleures performances puisqu’elle a permis de réduire le glycérol en 1,2-PDO avec une sélectivité élevée de 85%. Enfin, la réaction conduit aussi à la formation d’acétol et de diéthylèneglycol. Les mécanismes de formation des différents produits obtenus à partir de chaque réaction sont proposés.The price of crude glycerol has significantly decreased worldwide because of its oversupply. Many chemical and biological processes have been proposed to transform glycerol into numerous value-added products, such as glycolic acid, 1,3-propanediol (1,3-PDO), 1,2-propanediol (1,2-PDO), glyceric acid, and lactic acid. However, these processes suffer from several drawbacks, including high production cost. Therefore, in this study, a simple and robust electrochemical synthesiswas developed to convert glycerol into various value-added compounds. This study reports for the first time the use of Amberlyst-15 as a reaction mediumand redox catalyst for electrochemical conversion of glycerol. In the first part, the electrochemical performance of Amberlyst-15 over platinum (Pt)electrode was compared with that of conventional acidic (H2SO4) and alkaline (NaOH) media. Other parameters such as reaction temperature [room temperature (27°C) to 80 °C] and applied current (1.0 A to 3.0 A) were also examined. Under the optimized experimental condition, this novel electrocatalytic method successfully converted glycerol into glycolic acid after 8 h of electrolysis, with a yield of 45% and selectivity of 65%, as well as to glyceric acid after 3 h of electrolysis, with a yield of 27% and selectivity of 38%. In the second part of this study, two types of cathode electrodes, namely, activated carbon composite(ACC) and carbon black diamond (CBD) electrodes, were used in electrochemical conversion of glycerol. To the best of our knowledge, electrochemical studies of glycerol conversion using these electrodes have not been reported yet. Glycerol was also successfully reduced to lactic acid, 1,2-PDO, and 1,3-PDO, in addition to oxidation compounds (e.g. glycolic acid). Three operating parameters, namely, catalyst amount (6.4% to 12.8% w/v), reaction temperature [room temperature (27 °C) to 80 °C], and applied current (1.0 A to 3.0 A), were tested. In the presence of 9.6% w/v Amberlyst-15 at 2.0 A and 80 °C, the selectivity of glycolic acid can reach 72% and 68% (with yield of 66% and 58%) for ACC and CBD electrodes, respectively. Lactic acid was obtained as the second largest compound, withselectivity of 16% and yield of 15% for the ACC electrode and 27% selectivity and 21% yield for the CBD electrode. Finally, electro-oxidation and electroreduction of glycerol were performed in a two-compartment cell separated by a cation exchange membrane (Nafion 117). This study only focused on the electroreduction region. Three cathode electrodes (Pt, ACC, and CBD) were evaluated under the following conditions: 2.0 A, 80 °C, and 9.6% w/v Amberlyst-15. ACC demonstrated excellent performance in the electroreduction study and successfully reduced glycerol to 1,2-PDO, with a high selectivity of 85%. The selectivity of 1,2-PDO on Pt and CBD was 61% and 68%, respectively. Acetol and diethylene glycol were also obtained. The reaction mechanisms underlying the formation of these products are then proposed