d,l-S-Methyllipoic Acid Methyl Ester, a Kinetically Viable Model for S-Protonated Lipoic Acid as the Oxidizing Agent in Reductive Acyl Transfers Catalyzed by the 2-Oxoacid Dehydrogenase Multienzyme Complexes†

Background: The photo-absorption and light trapping through the different layers of the organic solar cell structures are a growing concern now-a-days as it affects dramatically the overall efficiency of the cells. In fact, selecting the right material combination is a key factor in increasing the efficiency in the layers. In addition to good absorption properties, insertion of nanostructures has been proved in recent researches to affect significantly the light trapping inside the organic solar cell. All these factors are determined to expand the absorption spectrum and tailor it to a wider spectrum. Objective: The purpose of this investigation is to explore the consequence of the incorporation of the Ag nanostructures, with different sizes and structures, on the photo absorption of the organic BHJ thin films. Methods: Through a three-dimensional Maxwell solver software, Lumerical FDTD, a simulation and comparison of the optical absorption of the three famous organic materials blends poly(3- hexylthiophene): phenyl C71 butyric acid methyl ester (P3HT:PCBM), poly[N-9″-heptadecanyl-2,7- carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)]: phenyl C71 butyric acid methyl ester (PCDTBT:PCBM) and poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b′]dithiophene)-alt- 4,7-(2,1,3-benzothiadiazole)]: phenyl C71 butyric acid methyl ester (PCDPDTBT:PCBM) has been conducted. Furthermore, FDTD simulation study of the incorporation of nanoparticles structures with different sizes, in different locations and concentrations through a bulk heterojunction organic solar cell structure has also been performed. Results: It has been demonstrated that embedding nanostructures in different locations of the cell, specifically in the active layer and the hole transporting layer had a considerable effect of widening the absorption spectrum and increasing the short circuit current. The effect of incorporation the nanostructures in the active layer has been proved to be greater than in the HTL. Furthermore, the comparison results showed that, PCDTBT:PCBM is no more advantageous over P3HT:PCBM and PCPDTBT:PCBM, and P3HT:PCBM took the lead and showed better performance in terms of absorption spectrum and short circuit current value. Conclusion: This work revealed the significant effect of size, location and concentration of the Ag nanostructures while incorporated in the organic solar cell. In fact, embedding nanostructures in the solar cell widen the absorption spectrum and increases the short circuit current, this result has been proven to be significant only when the nanostructures are inserted in the active layer following specific dimensions and structures.

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Kinetic study of the carbonation of epoxidized fatty acid methyl ester catalyzed over heterogeneous catalyst HBimCl‐NbCl 5 /HCMC

International Journal of Chemical Kinetics ◽

10.1002/kin.21526 ◽

2021 ◽

Author(s):

Xiaoshuang Cai ◽

Pasi Tolvanen ◽

Pasi Virtanen ◽

Kari Eränen ◽

Jani Rahkila ◽

...

Keyword(s):

Fatty Acid ◽

Methyl Ester ◽

Fatty Acid Methyl Ester ◽

Kinetic Study ◽

Heterogeneous Catalyst ◽

Acid Methyl Ester ◽

Acid Methyl

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Evaluation of 3-Methylbutanoic Acid Methyl Ester as a Factor Influencing Flavor Cleanness in Arabica Specialty Coffee

Applied Sciences ◽

10.3390/app11125413 ◽

2021 ◽

Vol 11 (12) ◽

pp. 5413

Author(s):

Keiko Iwasa ◽

Harumichi Seta ◽

Yoshihide Matsuo ◽

Koichi Nakahara

Keyword(s):

Methyl Ester ◽

Methyl Esters ◽

Acid Methyl Ester ◽

Chemical Compounds ◽

Gas Chromatography Mass Spectrometry ◽

Arabica Coffee ◽

Acid Methyl ◽

Coffee Brew ◽

Coffee Beans ◽

Specialty Coffee

This paper reports on the chemical compounds in arabica coffee beans with a high Specialty Coffee Association (SCA) cupping score, especially those in specialty coffee beans. We investigated the relationship between the chemical compounds and cupping scores by considering 16 types of Coffea arabica (arabica coffee) beans from Guatemala (SCA cupping score of 76.5–89.0 points). Non-targeted gas chromatography-mass spectrometry-based chemometric profiling indicated that specialty beans with a high cupping score contained considerable amounts of methyl-esterified compounds (MECs), including 3-methylbutanoic acid methyl ester (3-MBM), and other fatty acid methyl esters. The effect of MECs on flavor quality was verified by spiking the coffee brew with 3-MBM, which was the top-ranked component, as obtained through a regression model associated with cupping scores. Notably, 3-MBM was responsible for the fresh-fruity aroma and cleanness of the coffee brew. Although cleanness is a significant factor for specialty beans, the identification of compounds that contribute to cleanness has not been reported in previous research. The chemometric profiling approach coupled with spiking test validation will improve the identification and characterization of 3-MBM commonly found in arabica specialty beans. Therefore, 3-MBM, either alone or together with MECs, can be used as a marker in coffee production.

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