Interesterification of rapeseed oil with methyl acetate in the presence of potassium tert-butoxide solution in tetrahydrofuran

Conventionally, the biodiesel (mixture of fatty acid methyl esters, FAME) production proceeds by transesterification of triglycerides with methanol accordingly by the formation of glycerol as a by-product, which cannot be included in biofuel composition. Biodiesel could also be produced via interesterification ensuring full conversion of oil to biofuel, consisting of FAME and triacetin. The most effective catalysts for interesterification reactions are alkali metal alkoxides. The effectivity of alkoxide catalyst depends on its solubility determined by the structure of the alkyl chain. In our previous studies, we have shown that the branched chain catalyst tert-BuOK/THF is highly suitable for the realisation of interesterification reactions. Till now, in the scientific literature, very little is known about the influence of metal ions. In order to investigate the influence of counterion on the activity of alkoxide catalysts, in this work, we have investigated the proceeding of interesterification reactions of rapeseed oil with methyl acetate in the presence of lithium, sodium, and potassium tert-butoxides in THF. Experimentally obtained relationships for catalyst-to-oil molar ratio (COMR) influence rapeseed oil interesterifications with methyl acetate at 55°C for 1 h, with methyl acetate-to-oil molar ratio (MAOMR) 18 showing that the tert-BuONa/THF and tert-BuOK/THF have high and similar activity, but the tert-BuOLi/THF is fundamentally different. The low and diverse activity of lithium tert-butoxide can be explained by the association of ions and very low catalytic activity of ion pairs. Simulation of the influence of association on the FAME formation shows that at COMR 0.1 (sufficient for fast reaction proceeding in the presence of tert-BuONa/THF and tert-BuOK/THF), the concentration of tert-butoxide ions in the presence of tert-BuOLi/THF because of associations lowers from 28 mmol/L to 13 mmol/L, whcih is not sufficient for effective proceeding of reaction. Activity of alkoxides in this reaction is solely determined by the counterion.

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Factors Affecting Biodiesel Yield in Interesterification of Rapeseed Oil by Supercritical Methyl Acetate

Zero-Carbon Energy Kyoto 2011 - Green Energy and Technology ◽

10.1007/978-4-431-54067-0_16 ◽

2012 ◽

pp. 147-152 ◽

Cited By ~ 4

Author(s):

Fadjar Goembira ◽

Shiro Saka

Keyword(s):

Rapeseed Oil ◽

Methyl Acetate ◽

Factors Affecting

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Studying the kinetics of rapeseed oil reactions with methanol, methyl formate, and methyl acetate under mild conditions for biodiesel production

Biofuels ◽

10.1080/17597269.2020.1827929 ◽

2020 ◽

pp. 1-8

Author(s):

Zane Abelniece ◽

Valdis Kampars

Keyword(s):

Rapeseed Oil ◽

Methyl Acetate ◽

Methyl Formate ◽

Biodiesel Production ◽

Mild Conditions ◽

Kinetics Of

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Competitive Interesterification-Transesterification of Rapeseed Oil with Methyl Acetate in Presence of Potassium Metoxide Solutions

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.762.158 ◽

2018 ◽

Vol 762 ◽

pp. 158-162 ◽

Cited By ~ 3

Author(s):

Elina Sile ◽

Valdis Kampars ◽

Zane Sustere

Keyword(s):

Catalytic System ◽

Rapeseed Oil ◽

Methyl Acetate ◽

Catalytic Systems ◽

Tert Butanol

Two catalytic systems (CH3OK/CH3OH and CH3OK/tert-BuOH) were tested to estimate competitive interesterification-transesterification processes of rapeseed oil with methyl acetate. Catalyst completely dissolves in methanol, while in tert-butanol suspension was obtained. With CH3OK/CH3OH catalytic system high FAME content was obtained (86 wt%), but triacetin content was negligible and without FAME mostly transesterification products of oil and triacetin were observed (up to 94 wt% of all products). When CH3OK/tert-BuOH catalytic system was used, only interesterification of oil proceeded, nevertheless the composition of product complicated the interesterification of triacetin with tert-butanol.

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Rapeseed Oil Interesterification Reaction with Metylacetate in the Presence of BuOK/BuOH at Different Temperatures

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.800.83 ◽

2019 ◽

Vol 800 ◽

pp. 83-87

Author(s):

Valdis Kampars ◽

Reinis Gravins ◽

Kristine Lazdovica

Keyword(s):

Reaction Time ◽

Characteristic Time ◽

Rapeseed Oil ◽

Methyl Acetate ◽

Biodiesel Production ◽

Molar Ratio ◽

First Order ◽

Different Temperatures ◽

Pseudo First Order ◽

Synthesis Stage

By the investigation and comparison of different interesterification reactions at fixed reaction time researchers usually selected 1 hour as a characteristic time for the synthesis stage of industrial biodiesel production. Investigation performed in this work shows that the equilibrium of interesterification reaction mixture of rapeseed oil with methyl acetate in molar ration of 1:18 in presence of potassium tert-butoxide in tert-butanol at molar ratio to oil 0.08 at 25 °C reach the equilibrium approximately after 50 min but at 55 °C after 10 min. The equilibrium compositions of the reaction mixtures at different temperatures are different. The concentrations of TG, FAME and TA during the interesterification reaction at 25 °C obey the pseudo-first order law which do not reflect the stoichiometry of this multiple elementary steps reaction.

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Effect of Temperature on Interesterification of Rapeseed Oil with Methyl Acetate in Presence of BuOK/BuOH

E3S Web of Conferences ◽

10.1051/e3sconf/201910302006 ◽

2019 ◽

Vol 103 ◽

pp. 02006

Author(s):

Valdis Kampars ◽

Reinis Gravins ◽

Kristine Lazdovica ◽

Ruta Kampare

Keyword(s):

Reaction Time ◽

Rapeseed Oil ◽

Methyl Acetate ◽

Order Rate Constant ◽

Effect Of Temperature ◽

Molar Ratio ◽

Optimal Range ◽

First Order ◽

Pseudo First Order ◽

Full Conversion

If the interesterification reaction of rapeseed oil with methyl acetate at reactant to oil molar ratio of 18:1 in presence of potassium tert-butoxide in tert-butanol of molar ratio to oil 0.08 is conducted at a temperature of about 35 °C, reaction time for full conversion of oil is shorter than one hour, while at a temperature of 55 °C it is approximately 15 minutes. Reaction time at the desired temperature has a wide "optimal" range and cannot be an effective variable for the process optimisation. Experimental results at the temperature of 25 °C confirm the pseudo-first order of the reaction, which lowered towards the end of the reaction. The pseudo-first order rate constant was 0.63 min-1. Fuel characteristics of the interesterification reaction mixtures without purification improved with the rising of reaction temperature from 35 °C to 55 °C, however, they fail to meet the requirements of standard EN14214 for biodiesel. Methyl acetate to oil molar ratio 18:1 is too low for obtaining products with kinematic viscosity below 5.0 mm2/s.

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BIOFUEL VIA INTERESTERIFICATION OF RAPESEED OIL WITH METHYL ACETATE IN PRESENCE OF POTASSIUM t-BUTOXIDE/THF

SWS Journal of EARTH AND PLANETARY SCIENCES ◽

10.35603/eps2019/issue1.01 ◽

2019 ◽

Vol 1 (1) ◽

pp. 1-10 ◽

Cited By ~ 1

Author(s):

Valdis Kampars ◽

Zane Abelniece ◽

Ruta Kampare

Keyword(s):

Catalytic System ◽

Sodium Methoxide ◽

Rapeseed Oil ◽

Methyl Acetate ◽

Side Reaction ◽

Conversion Process ◽

Homogeneous Catalyst ◽

Hydroxyl Groups ◽

Full Conversion ◽

Alcoholic Hydroxyl

Transesterification does not allow to make full conversion of oil to biodiesel because the by-product glycerol cannot be included in the composition of biofuel. Interesterification constitutes a full conversion process with production of triacetin (TA) instead of glycerol, which can be included in the composition of biofuel and allows to increase its yield. Both interesterification and transesterification effectively occur only in presence of catalysts. Results of the investigation of heterogeneous and homogeneous catalysts indicate the superior importance of catalyst solubility in starting reaction mixture. Partial solubility can remarkably lower the activity of homogeneous catalyst and extremely increase that of formally heterogeneous one. The reaction mixture of interesterification reaction is less polar than that of transesterification, and potassium tert-butoxide (t-BuOK) should be more appropriate catalyst for interesterification than sodium methoxide which is used in most cases. The catalytic system t-BuOK/t-BuOH substantially increases the yield of TA and changes the properties of obtained biofuel. Whereas the content of the TA in the interesterification reaction mixture does not achieve the same level from the theoretically predicted as the FAME, the occurrence of side reaction between t-BuOH and TA cannot be excluded. This paper presents a study of the interesterification of rapeseed oil in presence of catalytic system t-BuOK/THF (catalytic system without alcohols) with the aim of establishing the influence of aprotic tetrahydrofuran to the proceeding the reaction, composition of reaction mixtures and their fuel properties. Obtained results show that the absence of alcoholic hydroxyl groups in the catalytic system insufficiently increases the activity of catalytic system but fails to increase the yield of FAME.

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BIOFUEL VIA INTERESTERIFICATION OF RAPESEED OIL WITH METHYL ACETATE IN PRESENCE OF POTASSIUM t-BUTOXIDE/THF

18th International Multidisciplinary Scientific GeoConference SGEM2018, Energy and Clean Technologies ◽

10.5593/sgem2018/4.1/s17.022 ◽

2018 ◽

Cited By ~ 2

Author(s):

Valdis Kampars

Keyword(s):

Rapeseed Oil ◽

Methyl Acetate

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Rapeseed Oil and Sunflower Oil Diets Enhance Platelet In Vitro Aggregation and Thromboxane Production in Healthy Men when Compared with Milk Fat or Habitual Diets

Thrombosis and Haemostasis ◽

10.1055/s-0038-1648446 ◽

1992 ◽

Vol 67 (03) ◽

pp. 352-356 ◽

Cited By ~ 34

Author(s):

Marja Mutanen ◽

Riitta Freese ◽

Liisa M Valsta ◽

Irma Ahola ◽

Antti Ahlström

Keyword(s):

Sunflower Oil ◽

Milk Fat ◽

Rapeseed Oil ◽

Controlled Trial ◽

Collagen Concentration ◽

Aggregation Pattern ◽

Thromboxane Production ◽

Low Erucic Acid ◽

Platelet Thromboxane

SummaryIn this highly controlled trial, 26 normolipidemic men (average age 28 years, range 18 to 60) were fed a baseline diet high in milk fat (MF) (fat 36% of energy, saturates 19%, monounsaturates 11%, polyunsaturates 4%), followed by a diet high in sunflower oil (SO) (fat 38% of energy, saturates 13%, monounsaturates 10%, polyunsaturates 13%) and another diet high in low erucic-acid rapeseed oil (RO) (fat 38% of energy, saturates 12%, monounsaturates 16%, polyunsaturates 8%). All diets were mixed natural diets with the same cholesterol contents. The baseline milk fat diet was given for 14 days and the oil diets for 24 days in a blind cross-over design. The platelet in vitro aggregation (slope %/min) induced by 1, 2 and 3 pM ADP and collagen (25 pg/ml PRP) was highly significantly (p <0.001) increased after both oil diets when compared with the results from the milk fat diet. The aggregation pattern determined by threshold collagen concentration confirmed increased collagen sensitivity of the platelets after the rapeseed oil diet (p <0.001). The enhancement of platelet aggregation was associated with increased in vitro platelet thromboxane production after the oil diets vs. the milk fat diet (p <0.05 after the sunflower oil diet and p <0.001 after the rapeseed oil diet).

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