Ethanolysis of waste cottonseed oil over lithium impregnated calcium oxide: Kinetics and reusability studies

A series of Li/CaO catalysts has been prepared by impregnating 0.5–5.0 wt% Li in CaO by wet chemical method. Prepared Li/CaO catalysts have been characterized by powder X-ray diffraction, scanning electron and transmission electron microscopy and Brunauer–Emmett–Teller (BET) surface area studies, in order to establish the structure and surface morphology of the catalyst. Hammett indicator test study was performed to determine the basic strength of the Li/CaO catalysts. The prepared Li/CaO catalysts have been employed as a heterogeneous catalyst for the transesterification of waste cottonseed oil (having 2.8 wt% free fatty acid contents) with ethanol. Under optimal reaction conditions viz., ethanol/oil molar ratio of 12:1, catalyst to oil weight fraction of 5% and 65 °C reaction temperature, 98% fatty acid ethyl ester yield was obtained in 2.5 h of reaction duration. Under the optimized reaction conditions, the pseudo first order constant and Arrhenius activation energy were found to be 0.03 min⁻¹ and 70.0 kJ mol⁻¹, respectively. Further Li/CaO catalyst was also found to be effective for the ethanolysis and methanolysis of vegetable oils having up to 3.4 wt% free fatty acids. The use of 3-Li/CaO catalyst is advantageous considering that it not only utilizes waste cottonseed oil as a feedstock, but also renewable and nontoxic alcohol, ethanol, for the biodiesel production.     

Versuchsplanerische Untersuchung der Umesterung von Sojaöl mit Ethanol im Mikroreaktor

Base‐catalyzed transesterification of fats and oils with primary alcohols in discontinuous operation is an established batch process for the biodiesel production. However, the application of microreaction technology and continuous flow process lead to an increase of process intensification. The ethanol/soy bean oil ratio at low flow rates as well as the reactor geometry have the most evident effects on the fatty acid ethyl ester yield of KOH‐catalyzed ethanolysis of soy bean oil in microreactors. The influence of the catalyst concentration is of a lower importance.     

Ethanolysis of Refined Soybean Oil Assisted by Sodium and Potassium Hydroxides

The ethanolysis of refined soybean oil was investigated through a 2³ experimental design that was carried out under the following levels: ethanol:oil molar ratios (MR) of 6:1 and 12:1, NaOH concentrations of 0.3 and 1.0 wt% in relation to the oil mass, and reaction temperatures of 30 and 70 °C. The ethanol:oil MR and the alkali concentration had an almost equivalent influence on the reaction yield, whereas the influence of increased reaction temperatures was very limited and higher catalyst concentrations led to greater yield losses due to the formation of soap. Ethyl ester yields of 97.2% were obtained at 70 °C, MR of 12:1 and 0.3 wt% NaOH. Replacement of 0.3 wt% NaOH by 1.0 wt% KOH under the same reaction conditions led to lower ester yields. Likewise the former, KOH provided the maximum ester yield (95.6%) at the highest molar ratio (12:1), with the reaction temperature having little influence on the catalyst performance. Ester yields beyond 98% were only achieved when a second ethanolysis stage was included in the process. In this regard, the application of 2 wt% Magnesol^® after the first ethanolysis stage eliminated the need for water washing prior to the second ethanolysis stage and helped to generate a final product with less contaminating unreacted glycerides.     

Lipase‐catalysed enrichment of DHA and EPA in acylglycerols resulting from squid oil ethanolysis

The fatty acid specificity of four lipases towards eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) was evaluated when performing ethanolysis of squid oil. During the first part of ethanolysis, no DHA ethyl esters were detected when using the lipases from Thermomyces lanuginosus, Pseudomonas cepacia or Pseudomonas fluorescens (in the case of the second and third lipases, no EPA ethyl esters were detected either). This indicates that these three lipases could not catalyse the conversion of DHA located in a triacylglycerol to ethyl ester, and that the Pseudomonas lipases could not catalyse the conversion of EPA either. This pattern was not found for the lipase from Rhizomucor miehei. The lipase from Thermomyces lanuginosus showed the lowest specificity towards DHA and the highest DHA recovery during DHA enrichment in the acylglycerol fraction. It was thus used to catalyse the ethanolysis of squid oil on a larger scale. The ethyl esters formed were removed using short‐path distillation, resulting in a product containing mainly mono‐ and diacylglycerols. The product contained 34 mol‐% DHA and 17 mol‐% EPA, compared with 19 mol‐% DHA and 12 mol‐% EPA in the original squid oil.     

Influence of process parameters on enhanced hydrogen evolution from alcoholysis of sodium borohydride with a boric acid catalyst

The hydrogen evolution via alcoholysis reaction of sodium borohydride with an H₃BO₃ catalyst was carried out for the first time. In the process of methanol and NaBH₄ (NaBH₄-MR), the effects of the H₃BO₃ and NaBH₄ concentration, and temperature parameters were examined and evaluated. The hydrogen yields by the NaBH₄-MR, NaBH₄ ethanolysis (NaBH₄-ER) and NaBH₄ hydrolysis reactions (NaBH₄-HR) with 0.2 M H₃BO₃ catalyst are 99, 62, and 88% compared to the theoretical hydrogen yield, respectively. The completion times of the NaBH₄-MR using the H₃BO₃ concentrations of 0.2, 0.4, 0.5, 1 M, and saturated acid solution were about 50, 15, 10, 2 and 1 min, respectively. The hydrogen yields obtained with 50, 15, 10, 2, and 1 min for the same acid concentration values were about 100% compared to the theoretical hydrogen value. By increasing the H₃BO₃ concentration from 0.2 M to the saturated H₃BO₃ concentration, the completion time of this NaBH₄-MR process was reduced by approximately 50 times, resulting in a significant result. The activation energy (Ea) of the NaBH₄-MR with the H₃BO₃ catalyst was 57.3 kJ/mol.     

Discrimination against diacylglycerol ethers in lipase-catalysed ethanolysis of shark liver oil

Lipase-catalysed ethanolysis of squalene-free shark liver oil was investigated. The mentioned shark liver oil was comprised mainly of diacylglycerol ether and triacylglycerols. In order to test discrimination against diacylglycerol ether, up to 10 different lipases were compared. The ratio of oil to ethanol and lipase stability were also evaluated. Surprisingly, lipase from Pseudomonas stutzeri was the fastest biocatalyst among all assayed, although poor discrimination against diacylglycerol ether was observed. The best results in terms of selectivity and stability were obtained with immobilised lipase from Candida antarctica (Novozym 435). Ethanolysis reaction after 24 h in the presence of Novozym 435 produced total disappearance of triacylglycerol and a final reaction mixture comprised mainly of diacylglycerol ethers (10.6%), monoacylglycerol ethers (32.9%) and fatty acid ethyl esters (46.0%). In addition, when an excess of ethanol was used, diacylglycerol ethers completely disappeared after 15 h, giving a final product mainly composed of monoacylglycerol ethers (36.6%) and fatty acid ethyl esters (46.4%).     

Lipase Catalyzed Synthesis of Medium-chain Biodiesel from Cinnamonum camphora Seed Oil☆

The non-edible camphor tree seed oil was extracted and catalyzed by immobilized lipase for biodiesel produc-tion. The oil yield from camphor tree seeds reached 35.2%of seed weight by twice microwave-as...     

Study of TAG ethanolysis to 2-MAG by immobilized Candida antarctica lipase and synthesis of symmetrically structured TAG

Regiospecific ethanolysis of homogenous TAG with immobilized Candida antarctica lipase (Novozym 435) was studied using trioleoylglycerol (TO) as a model substrate. Optimization of the reactant weight ratio revealed that the 2-MAG reaction yield increased when a larger amount of ethanol was used. These results suggested that Novozym 435 showed strict regiospecificity in an excess amount of ethanol. The process optimization (reaction temperature and reactant molar ratio) and a study of lipase specificity for various substrates were performed. Under the optimized conditions (ethanol/TO molar ratio=77∶1 and 25°C), 2-monooleoylglycerol (2-MO) was obtained in more than 98% content among glycerides of the reaction mixture and approximately 88% reaction yield in 4 h. The above reaction conditions were applied for ethanolysis of tridocosahexaenoylglycerol, trieicosapentaenoylglycerol, triarachidonoylglycerol, tri-α-linolenoylglycerol, and trilinoleoylglycerol. Reaction yields ranging from 71.9 to 93.7% were obtained in short reaction times (2.5 to 8 h). Purified (>98%) 2-MO and 2-monodocosahexaenoylglycerol (2-MD) were reesterified with caprylic acid by immobilized Rhizomucor miehei lipase (Lipozyme IM) to afford symmetrical structured TAG. At a stoichiometric ratio of 2-MAG/caprylic acid, 25°C and 2–5 mm Hg vacuum, the glyceride composition of the esterification mixture was approximately 95% 1,3-dicapryloyl-2-oleoylglycerol (COC) at 4 h, and 96% 1,3-dicapryloyl-2-docosahexaenoylglycerol (CDC) at 4 h, and 96% 1,3-dicapryloyl-2-docosahexaenoylglycerol (CDC) at 8 h. The regioisomeric purity of both COC and CDC was 100%.     

Effect of reaction parameters on conversion of krill (Euphausia superba) oil by immobilized lipase ethanolysis

Monoglyceride and diglyceride were produced by performing ethanolysis of krill oil with immobilized lipase and the influence of various parameters on the enzymatic ethanolysis was assessed. As an immobilized lipase, lipozyme TL-IM (thermonuces lanuginose) was used. Ethanolysis was done in non-pressurized and pressurized system to compare the reaction rate and yield. The optimal condition was found at 2.0 of ethanol mole ratio, temperature of 60 °C, lipases amount of 5 wt% in non-pressurized system. At pressurized system the optimal temperature and pressure was found at 50 °C and 10 MPa. However, at 50 °C monoglyceride was higher in pressurized system than in non-pressurized system.