Electron Affinity of Phenyl-C61-Butyric Acid Methyl Ester (PCBM)
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14 SOLAR ENERGY↗
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ACCURATE BOND ENERGIES OF BIODIESEL METHYL ESTERS FROM MULTIREFERENCE AVERAGED COUPLED-PAIR FUNCTIONAL CALCULATIONS
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biofuels (including algae and biomass), hydrogen a↗
Role of Domain Size and Phase Purity on Charge Carrier Density, Mobility, and Recombination in Poly(3-hexylthiophene):Phenyl-C61-butyric Acid Methyl Ester Devices
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charge transport↗
Low Temperature Chlorine-Initiated Oxidation of Small-Chain Methyl Esters: Quantification of Chain-Terminating HO 2 -Elimination Channels
In this paper, Cl-initiated oxidation reactions of three small-chain methyl esters, methyl propanoate (CH 3 CH 2 COOCH 3 ; MP), methyl butanoate (CH 3 CH 2 CH 2 COOCH 3 ; MB), and methyl valerate (CH 3 CH 2 CH 2 CH 2 COOCH 3 ; MV), are studied at 1 or 8 Torr and 550 and 650 K. Products are monitored as a function of mass, time, and photoionization energy using multiplexed photoionization mass spectrometry coupled to tunable synchrotron photoionization radiation. Pulsed photolysis of molecular chlorine is the source of Cl radicals, which remove an H atom from the ester, forming a free radical. In each case, after addition of O 2 to the initial radicals, chain-terminating HO 2 -elimination reactions are observed to be important. Branching ratios among competing HO 2 -elimination channels are determined via absolute photoionization spectra of the unsaturated methyl ester coproducts. At 550 K, HO 2 -elimination is observed to be selective, resulting in nearly exclusive production of the conjugated methyl ester coproducts, methyl propenoate, methyl-2-butenoate, and methyl-2-pentenoate, respectively. However, in MV, upon raising the temperature to 650 K, other HO 2 -elimination pathways are observed that yield methyl-3-pentenoate and methyl-4-pentenoate. In each methyl ester oxidation reaction, a peak is observed at a mass consistent with cyclic ether formation, indicating chain-propagating OH loss/ring formation pathways via QOOH intermediates. Evidence is observed for the participation of resonance-stabilized QOOH in the most prominent cyclic ether pathways. Finally, stationary point energies for HO 2 -elimination pathways and select cyclic ether formation channels are calculated at the CBS-QB3 level of theory and assist in the assignment of reaction pathways and final products.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Synthesis and characterization of methyl esters from non-edible plant species yellow oleander oil, using magnesium oxide (MgO) nano-catalyst
Highlights: • Introduction of new non-edible oil source for bioenergy industry. • Nano-particles MgO used as a heterogeneous catalyst. • Maximum conversion yield at optimum level achieved 93.1%. • Fuel properties were matched and found similar to ASTM standards. - Abstract: Synthesis and characterization of methyl esters from non-edible oil sources provide a distinctive and sustainable approach towards sustainable energy and the cleaner environment, in general. This study aims the synthesis of methyl esters from non-edible plant species yellow oleander seeds oil. The transesterification process was carried for the synthesis of methyl esters, using heterogeneous nano-catalyst magnesium oxide (MgO). A well known co-precipitation method was used for the synthesis of MgO nano-catalyst. The application of MgO nano-catalyst showed the maximum conversion (93.1%) of triacylglycerols to methyl esters. Different parameters affecting the conversion percentage; alcohol to oil molar ratio, temperature and catalyst concentrations were checked and optimized, accordingly. The optimum conditions for the maximum conversion noted; 1:5 oil to methanol molar ratio at 90 °C, using 0.2% (w/w) MgO nano-catalyst. The various analytical techniques; XRD, SEM-EDX and TEM-EDS spectroscopes were used to check out the nano-particle morphology and crystalline size, accordingly while, the FTIR, GC–MS & NMR were used to quantify and determine the structural measurements of synthesized methyl esters. The fuel properties of oleander methyl esters papered sample were checked, compared and found within accordance to the ASTM standards.
09 BIOMASS FUELS↗
Bond Dissociation Energies of C 10 and C 18 Methyl Esters from Local Multireference Averaged-Coupled Pair Functional Theory
We previously developed a fast, local, reduced scaling Cholesky-decomposed multireference averaged-coupled pair functional (CD-LMRACPF2) method, which takes advantage of the locality of dynamic correlation and numerical approximations such as Cholesky decomposition and integral screening. Motivated by the desire to study large biodiesel methyl ester molecules, here we validate CD-LMRACPF2 for the computation of bond dissociation energies (BDEs) in a suite of oxygenated molecules, and show that the low-cost method is very accurate compared to the conventional variant. We then demonstrate the power of CD-LMRACPF2 for fast and accurate computation of energies of molecules containing up to 13 second-row atoms within a polarized triple-ζ (cc-pVTZ) basis set. We use biodiesel methyl esters as a chemically interesting model system and furnish BDEs of C 10 and C 18 methyl esters, with the latter performed within a cc-pVDZ basis set. Here, we describe trends in the BDEs and explain how structural (isomeric) differences affect BDEs, as well as discuss implications of BDE trends for biodiesel physical and chemical properties.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Fuel property evaluation of unique fatty acid methyl esters containing β-hydroxy esters from engineered microorganisms
Unique fatty acid methyl esters (FAME) containing ..beta..-hydroxy esters were produced using an engineered microorganism by glucose fermentation. This study investigated the properties of the unique FAME mixture both neat and in blends with conventional diesel, as well as properties of ..beta..-hydroxy esters. The unique FAME blend contained relatively shorter-chain FAME (average fatty acid chain carbon number 14.6) with 58 % monounsaturated fatty acids and 9 % saturated and monounsaturated ..beta..-hydroxy acid chains. The unique FAME had significantly lower distillation T90 (321 °C versus 352 °C) and higher cetane number (56.7 versus 52) compared to soy biodiesel. Cloud points were within method repeatability. Unexpectedly (because of the lack of methylene-interrupted double bonds), the unique FAME had low oxidation stability (1.5 h) as determined by Rancimat induction period. Stability could be improved through addition of commonly used antioxidants. We speculate that monounsaturated ..beta..-hydroxy FAME may be the source of this instability. Blends with conventional diesel up to 50 vol% showed similar kinematic viscosity (within method repeatability) as blends of conventional FAME. The unique FAME had no effect on distillation T90 even at the 80% blend level. A 30 vol% blend into conventional diesel had a Rancimat induction period of only 2 h, very nearly the same as the neat unique FAME sample. The addition of antioxidants produced blends of acceptable stability. Based on an assessment of the properties of individual ..beta..-hydroxy FAME molecules, they have higher boiling point, higher cloud point, lower cetane number, and potentially lower storage stability than analogous FAME not having the ..beta..-hydroxy group. Removing them from the fuel product in the production process may result in a biodiesel product with superior properties to what is on the market today.
09 BIOMASS FUELS↗
On the inapplicability of electron-hopping models for the organic semiconductor Phenyl-C61-butyric Acid Methyl Ester (PCBM)
Phenyl-C61-butyric Acid Methyl Ester (PCBM) is one of the most popular semiconductors in organic photovoltaic cells, but the electron transport mechanism in the microcrystalline domains of this material as well as its preferred packing structure remains unclear. Here we use density functional theory to calculate electronic coupling matrix elements, reorganization energies and activation energies for available experimental and model crystal structures. We find that the picture of an excess electron hopping from one fullerene to another does not apply for any of the crystalline phases, rendering traditional rate equations inappropriate. We also find that the cohesive energy increases in the order body-centred-cubic < hexagonal < simple cubic < monoclinic < triclinic, independently on the type of dispersion correction used. Our results indicate that the electron-ion dynamics needs to be solved explicitly in order to obtain a realistic description of charge transfer in this material. M.D. was supported by the U.S. Department of Energy (DOE), Office of Basic Energy Sciences (BES), Division of Chemical Sciences, Geosciences and Biosciences. PNNL is a multiprogram national laboratory operated for DOE by Battelle.
Density Functional Theory↗
Determination of Total Lipids as Fatty Acid Methyl Esters (FAME) by in situ Transesterification: Laboratory Analytical Procedure (LAP)
This procedure is based on a whole biomass transesterification of lipids to fatty acid methyl esters to represent an accurate reflection of the potential of microalgal biofuels. Lipids are present in many forms and play various roles within an algal cell, from cell membrane phospholipids to energy stored as triacylglycerols.
09 BIOMASS FUELS↗
Benchmark Calculations for Bond Dissociation Enthalpies of Unsaturated Methyl Esters and the Bond Dissociation Enthalpies of Methyl Linolenate
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Li, Xiaoyu↗
Determination of Total Lipids as Fatty Acid Methyl Esters: Laboratory Analytical Procedure (LAP)
This Laboratory Analytical Procedure (LAP) covers the determination of total lipids expressed as fatty acid methyl esters (FAME). Results are reported as the percent FAME content based on the dry weight of the sample. The procedure is based on a whole biomass transesterification procedure of lipids to FAME, which eliminates the need for extraction and therefore is able to access all fatty acids in the biomass and represent an accurate reflection of the biofuels potential.
09 BIOMASS FUELS↗
Characterization of Kariya ( Hildegardia barteri (Mast.) Kosterm) Seed Oil Fatty Acid Methyl Ester Prepared from Basic Catalytic Transesterification
The rising global energy demand, alongside concerns regarding environmental deterioration due to the use of fossil fuels, has spurred extensive investigation into renewable energy alternatives. Biomass-derived biodiesel, especially from lesser-known oil sources, emerges as a promising option. This research focuses on analyzing the fatty acid methyl esters (FAMEs) derived from Kariya (Hildegardia barteri (Mast.) Kosterm) seed oil through basic catalytic transesterification using gas chromatography–flame ionization detector (GC–FID) analysis, assessing its potential as a biodiesel feedstock. Oil extraction from Kariya seeds was carried out using three solvents (n-hexane, ethanol, and a 1:1 blend of hexane and ethanol), followed by transesterification with methanol. Gas chromatography–mass spectrometry (GC–MS) and GC–FID analyses were utilized to identify and quantify FAMEs in the resulting biodiesel. The results revealed various FAMEs, including methyl myristate, methyl palmitate, methyl stearate, methyl oleate, methyl linoleate, and methyl linolenate. Significant differences in FAME composition were observed among the samples, with hexane–ethanol Kariya oil biodiesel (HE-KOB) showing the highest FAME content (76.1%). This combination of solvents exhibited synergistic effects on the composition of HE-KOB, suggesting potential optimization strategies for biodiesel production. Fourier transform infrared spectroscopy (FTIR) provided additional insights into the molecular composition of the biodiesel samples, confirming their biodiesel nature through the identified functional groups such as methyl, methylene, hydrocarbon, ester, aldehyde, and alkene. Thermogravimetric analysis (TGA) for thermal decomposition also gave an insight into FAME composition and its contribution to the degree of conversion of biodiesel to energy. These findings highlight the feasibility of utilizing Kariya seed oil as a biodiesel feedstock, emphasizing the importance of solvent selection and transesterification conditions in optimizing FAME yield and composition. This research contributes to the exploration of underutilized oil sources for sustainable biodiesel production, aligning with the global shift towards cleaner and renewable energy sources.
09 BIOMASS FUELS↗
Development of Multilayer Films Obtained From Epoxidized Methyl Esters, Polyhydroxyalkanoates and Their Combinations
The aim of this work was the production and characterization of films prepared from starch, gelatin and methyl esters of epoxidized macauba (Acrocomia aculeata), corn (Zea mays), pacu (Piaractus mesopotamicus), pintado (Pseudoplatystoma corruscans) and soybean (Glycine max) and also multilayer films of polyhydroxyalkanoates (PHA) conjugated with two of the epoxides that presented the best results in characterizations. The two types of films EEF (Epoxidized esters films) and EEFPHA (Epoxidized esters and PHA conjugated films) were both characterized for their visual aspects, solubility in water and acid, width, color, opacity, water vapor permeability, tensile strength and elongation. EEFPHA were also characterized by differential scanning calorimetry, scanning electron microscopy and X-ray diffraction analyses. The epoxidation reaction was successfully carried out; with the GC-MS analysis indicating the formation of epoxidized esters derived from linoleic and oleic acids. The addition of the epoxidized esters to the EEF films caused an increase in film thickness, opacity, solubility in water, tensile strength and elongation, while the solubility in acid presented the same value as compared to the blank sample. In the EEFPHA samples, addition of filmogenic solution of epoxidized esters from corn and macauba presented a value exceeding the standard in the thickness, opacity, water solubility, water vapor permeability and tensile strength analyses. In the analysis of solubility in acid these samples showed results below the standard, and the elongation test showed values very close. DSC, SEM and XRD results showed that there was a polymeric incorporation between the starch and the PHA.
77 NANOSCIENCE AND NANOTECHNOLOGY↗
Chikusetsusaponin IVa methyl ester induces cell cycle arrest by the inhibition of nuclear translocation of β-catenin in HCT116 cells
We demonstrate that chikusetsusaponin IVa methyl ester (CME), a triterpenoid saponin from the root of Achyranthes japonica, has an anticancer activity. We investigate its molecular mechanism in depth in HCT116 cells. CME reduces the amount of β-catenin in nucleus and inhibits the binding of β-catenin to specific DNA sequences (TCF binding elements, TBE) in target gene promoters. Thus, CME appears to decrease the expression of cell cycle regulatory proteins such as Cyclin D1, as a representative target for β-catenin, as well as CDK2 and CDK4. As a result of the decrease of the cell cycle regulatory proteins, CME inhibits cell proliferation by arresting the cell cycle at the G0/G1 phase. Therefore, we suggest that CME as a novel Wnt/β-catenin inhibitor can be a putative agent for the treatment of colorectal cancers. - Highlights: • CME inhibits cell proliferation in HCT116 cells. • CME increases cell cycle arrest at G0/G1 phase and apoptosis. • CME attenuates cyclin D1 and regulates cell cycle regulatory proteins. • CME inhibits β-catenin translocation to nucleus.
60 APPLIED LIFE SCIENCES↗
Traceable atomic force microscopy of high-quality solvent-free crystals of [6,6]-phenyl-C{sub 61}-butyric acid methyl ester
We report high-resolution, traceable atomic force microscopy measurements of high-quality, solvent-free single crystals of [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). These were grown by drop-casting PCBM solutions onto the spectrosil substrates and by removing the residual solvent in a vacuum. A home-built atomic force microscope featuring a plane mirror differential optical interferometer, fiber-fed from a frequency-stabilized laser (emitting at 632.8 nm), was used to measure the crystals' height. The optical interferometer together with the stabilized laser provides traceability (via the laser wavelength) of the vertical measurements made with the atomic force microscope. We find that the crystals can conform to the surface topography, thanks to their height being significantly smaller compared to their lateral dimensions (namely, heights between about 50 nm and 140 nm, for the crystals analysed, vs. several tens of microns lateral dimensions). The vast majority of the crystals are flat, but an isolated, non-flat crystal provides insights into the growth mechanism and allows identification of “molecular terraces” whose height corresponds to one of the lattice constants of the single PCBM crystal (1.4 nm) as measured with X-ray diffraction.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Graphene composite for improvement in the conversion efficiency of flexible poly 3-hexyl-thiophene:[6,6]-phenyl C{sub 71} butyric acid methyl ester polymer solar cells
The solution of thin graphene-sheets obtained from a simple ultrasonic exfoliation process was found to chemically interact with [6,6]-phenyl C{sub 71} butyric acid methyl ester (PCBM) molecules. The thinner graphene-sheets have significantly altered the positions of highest occupied molecular orbital and lowest unoccupied molecular orbital of PCBM, which is beneficial for the enhancement of the open circuit voltage of the solar cells. Flexible bulk heterojunction solar cells fabricated using poly 3-hexylthiophene (P3HT):PCBM-graphene exhibited a power conversion efficiency of 2.51%, which is a ∼2-fold increase as compared to those fabricated using P3HT:PCBM. Inclusion of graphene-sheets not only improved the open-circuit voltage but also enhanced the short-circuit current density owing to an improved electron transport.
36 MATERIALS SCIENCE↗
A novel approach for the characterization of a bilayer of phenyl-c71-butyric-acid-methyl ester and pentacene using ultraviolet photoemission spectroscopy and argon gas cluster ion beam sputtering process
The material arrangement and energy level alignment of an organic bilayer comprising of phenyl-c71-butyric-acid-methyl ester (PCBM-71) and pentacene were studied using ultraviolet photoelectron spectroscopy (UPS) and the argon gas cluster ion beam (GCIB) sputtering process. Although there is a small difference in the full width at half maximum of the carbon C 1s core level peaks and differences in the oxygen O 1s core levels of an X-ray photoemission spectroscopy spectra, these differences are insufficient to clearly distinguish between PCBM-71 and pentacene layers and to classify the interface and bulk regions. On the other hand, the valence band structures in the UPS spectra contain completely distinct configurations for the PCBM-71 and pentacene layers, even when they have similar atomic compositions. According to the valence band structures of the PCBM-71/pentacene/electrodes, the highest unoccupied molecular orbital (HOMO) region of pentacene is at least 0.8 eV closer to the Fermi level than that of PCBM-71 and it does not overlap with any of the chemical states in the valence band structure of PCBM-71. Therefore, by just following the variations in the area of the HOMO region of pentacene, the interface/bulk regions of the PCBM/pentacene layers were distinctly categorized. Besides, the variation of valence band structures as a function of the Ar GCIB sputtering time fully corroborated with the surface morphologies observed in the atomic force microscope images. In summary, we believe that the novel approach, which involves UPS analysis in conjunction with Ar GCIB sputtering, can be one of the best methods to characterize the material distribution and energy level alignments of stacks of organic layers.
36 MATERIALS SCIENCE↗
Broadband gain in poly(3-hexylthiophene):phenyl-C{sub 61}-butyric-acid-methyl-ester photodetectors enabled by a semicontinuous gold interlayer
Substantial broadband photoconductive gain has been realized for organic, thin-film photodetectors with a poly(3-hexylthiophene):phenyl-C{sub 61}-butyric-acid-methyl-ester (P3HT:PCBM) active layer at low bias voltages. External quantum efficiencies upwards of 1500% were achieved when a semicontinuous gold layer was introduced at the anode interface. Significant gain was also observed in the sub-band gap, near infrared region where the external quantum efficiency approached 100% despite the lack of a sensitizer. The gain response was highly dependent on the thickness of the active layer of the photodetector with the best results achieved with the thinnest devices. The gain is the result of the injection of secondary electrons due to hole charge trapping at the semicontinuous gold layer.
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗