Monitoring the Transesterification Reaction Used in Biodiesel Production, with a Low Cost Unilateral Nuclear Magnetic Resonance Sensor

Cabeça, Luis Fernando; Marconcini, L. V.; Mambrini, G. P.; Azeredo, Rodrigo Bagueira de Vasconcellos; Colnago, Luiz Alberto

doi:10.1021/ef200294j

Cited by 40 publications

(32 citation statements)

References 26 publications

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“…More recently, Linck et al [72] have shown the potential of applying a mobile LF 1 H NMR spectrometer for the analysis and monitoring of biodiesel production. Cabeça et al [73] suggested a method for off-line monitoring the biodiesel TE reaction using monoexponential fitting. In that study, monoexponential T 2 measurements were used to track the progression of the reaction until completion.…”

Section: Resultsmentioning

confidence: 99%

Novel 1H low field nuclear magnetic resonance applications for the field of biodiesel

Berman

Leshem

Etziony

et al. 2013

Biotechnol Biofuels

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BackgroundBiodiesel production has increased dramatically over the last decade, raising the need for new rapid and non-destructive analytical tools and technologies. 1H Low Field Nuclear Magnetic Resonance (LF-NMR) applications, which offer great potential to the field of biodiesel, have been developed by the Phyto Lipid Biotechnology Lab research team in the last few years.ResultsSupervised and un-supervised chemometric tools are suggested for screening new alternative biodiesel feedstocks according to oil content and viscosity. The tools allowed assignment into viscosity groups of biodiesel-petrodiesel samples whose viscosity is unknown, and uncovered biodiesel samples that have residues of unreacted acylglycerol and/or methanol, and poorly separated and cleaned glycerol and water. In the case of composite materials, relaxation time distribution, and cross-correlation methods were successfully applied to differentiate components. Continuous distributed methods were also applied to calculate the yield of the transesterification reaction, and thus monitor the progress of the common and in-situ transesterification reactions, offering a tool for optimization of reaction parameters.ConclusionsComprehensive applied tools are detailed for the characterization of new alternative biodiesel resources in their whole conformation, monitoring of the biodiesel transesterification reaction, and quality evaluation of the final product, using a non-invasive and non-destructive technology that is new to the biodiesel research area. A new integrated computational-experimental approach for analysis of 1H LF-NMR relaxometry data is also presented, suggesting improved solution stability and peak resolution.

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Section: Resultsmentioning

confidence: 99%

Novel 1H low field nuclear magnetic resonance applications for the field of biodiesel

Berman

Leshem

Etziony

et al. 2013

Biotechnol Biofuels

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“…The fatty acid composition, viscosity, CN, and iodine content of different intact oilseeds were estimated using 1 H transverse relaxation time T 2 data combined with chemometric techniques [22]. The transesterification reaction of oil was monitored in situ by measuring the transverse relaxation decay in the work by Cabeça et al [23]. Moreover, TD-NMR can be used to determine the CLs of fatty acid mixtures [24].…”

Section: Introductionmentioning

confidence: 99%

Molecular Properties of Fatty Acid Mixtures Estimated by Online Time-Domain NMR

Nikolskaya

Hiltunen

2018

Appl Magn Reson

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An approach based on time-domain nuclear magnetic resonance (TD-NMR) enables the estimation of the molecular properties of fatty acid mixtures-kinematic viscosity (µ), heating value (δ), cetane number (CN), and carbon chain length (CL). In this approach, the 1 H NMR spin-spin relaxation rates R 2 or times T 2 were used to determine these molecular properties. Online monitoring of the µ, δ, CN, and CL of fatty acid mixtures was performed using an online TD-NMR system that had been modified for flowing samples. The presented results show the potential of TD-NMR for online quality control during the production of liquid fuels.

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“…[19][20][21][22][23] It has also been used for identifying intermediates and for quantifying yields of fatty acid methyl esters (FAME) in the esterification and transesterification reactions. [24][25][26][27][28][29] Despite being a great technique for those purposes, it is not still very popular and not applied currently in industry due to the very expensive maintenance of a high-field NMR spectrometer, including cryogens, and the need of deuterated solvents for the analysis.In this work, we used a 1.40 T NMR spectrometer (60 MHz for proton) for the quantification of the reaction yield of the esterification reaction of fatty acids to produce FAME. The results were compared to that obtained on a 7.05 T high field spectrometer (300 MHz for proton) and also with a Fourier transformed infrared (FTIR) method associated with chemometrics analysis.…”

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confidence: 99%

Nuclear Magnetic Resonance (1.40 T) and Mid Infrared (FTIR-ATR) Associated with Chemometrics as Analytical Methods for the Analysis of Methyl Ester Yield Obtained by Esterification Reaction

Kollar¹,

Novotny²,

Nascimento³

et al. 2017

J. Braz. Chem. Soc.

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In this work, we compared 1.40 T nuclear magnetic resonance (NMR) to 7.05 T (60 and 300 MHz for proton, respectively), and mid-infrared with attenuated total reflectance (FTIR-ATR), associated with chemometrics methods, for the quantification of the reaction yield during esterification of fatty acids with methanol. The results showed that the integrated intensities of the ester C=O stretching region, relative to the total C=O stretching region, is useful to quantify the fatty acid methyl ester (FAME) concentration. Comparing the results obtained by the different final models: NMR (1.40 T and 7.05 T), FTIR-ATR using multivariate partial last squares regression (PLS) with orthogonal signal correction (OSC), and univariate ordinary least squares (OLS), the NMR of 1.40 T (60 MHz for proton) showed more advantages when compared to a high field spectrometer, due to the non-use of cryogenic and solvents and less laborious work for obtaining results. Keywords: biodiesel, esterification, mid-infrared, q-NMR, chemometrics IntroductionThe interest for using alternative fuels has grown in the last decade. 1 The increasing demand for energy and environmental awareness are leading researchers to look for new environmentally acceptable renewable resources. In this context, the interest for biodiesel has increased a lot since it is produced using renewable resources (oils and fats from both vegetable and animal sources), it is biodegradable, and it can be directly placed on diesel engines without any mechanical modifications, due to their similar physical chemical properties. Also it does not contain sulfur compounds, it releases less particulate matter and it is less toxic. 2,3The most common method used to produce biodiesel is the transesterification of fats and oils, using a strong base as catalyst (like NaOH, KOH or KOCH 3 ). It consists in the reaction between triacylglycerides and short chain alcohols to produce esters and glycerol. It is a reversible process and excess of alcohol is used for moving the equilibrium towards the products. However, this process needs feedstocks containing low concentrations of free fatty acids and water because they react with the basic catalysts forming soaps which hinders the purification of the biodiesel, increasing the cost of the production. 4 An alternative way is the esterification of fatty acids. 5,6 This reaction normally uses homogeneous acid catalysis with strong Brønsted acids such as H 2 SO 4 and HCl that are corrosive and should be neutralized when the process is finished. To overcome this problem, solid Lewis acids can be used allowing easy separation and continuous operation in reactors. 2The most common method used to monitor the reaction yield during the esterification is the determination of the amount of fatty acids, usually performed using chromatographic methods or titration with alcoholic solution of KOH (method described by AOCS Cd 3a-63). 7,8 Despite being very effective methods for this kind of analysis, they have the disadvantage of consuming large amounts of organ...

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Monitoring the Transesterification Reaction Used in Biodiesel Production, with a Low Cost Unilateral Nuclear Magnetic Resonance Sensor

Cited by 40 publications

References 26 publications

Novel 1H low field nuclear magnetic resonance applications for the field of biodiesel

Novel 1H low field nuclear magnetic resonance applications for the field of biodiesel

Molecular Properties of Fatty Acid Mixtures Estimated by Online Time-Domain NMR

Nuclear Magnetic Resonance (1.40 T) and Mid Infrared (FTIR-ATR) Associated with Chemometrics as Analytical Methods for the Analysis of Methyl Ester Yield Obtained by Esterification Reaction

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