Limonene Molecule Research Articles

Effective decapsulation method for photovoltaic modules: Limonene-induced EVA controlled swelling under sonication and debonding mechanism analysis

Waste crystalline silicon (c-Si) solar cells are rich in metal resources. The detachment of ethylene-vinyl acetate (EVA) copolymer is a critical step in the recycling of end-of-life (EoL) c-Si photovoltaic (PV) modules, but a clean and high-efficiency adhesive removal method is absent. In this study, we presented a green solvent-based approach using limonene with ultrasound assistance for the efficient delamination of EVA from c-Si PV modules. By adjusting the concentration of limonene solution, the degree of swelling of EVA was effectively controlled, reducing the risk of battery damage caused by uneven swelling. The application of an ultrasonic physical field to the swelling system expedited the diffusion and penetration of the swelling agent between the EVA layers, while simultaneously supplying energy for the fracture of cross-linking bonds. Under the optimized laboratory-scale condition (70 °C, 0.5 h and 0.1 M limonene), complete separation of the glass and backsheet from the EVA bonding layer was achieved. The intact c-Si solar cells thus have the potential to be fully recovered in subsequent processes. FT-IR tests and density functional theory (DFT) simulations confirmed that under ultrasound conditions, limonene molecules selectively attacked crosslinking bridges and side chains of ethyl vinyl acetate in the EVA molecular chain. This induced the breakdown of the EVA crosslinked network structure, resulting in a reduction in adhesive strength and ultimately achieving interlayer separation in 20min. The findings of this study provide theoretical support and technical insights for the clean and efficient recycling of PV modules.

Synthesis of an organic-inorganic composite from calcium carbonate and Kraft lignin and its use as carrier material for controlled release of semiochemical agents.

The control of pests in agricultural systems is currently based on the widespread use of pesticides that efficiently control pests but have negative effects on the environment and humans. Thus, several studies have been conducted to develop alternative sustainable ways to control pests in agriculture. The use of semiochemicals presents a good alternative to develop a sustainable tool monitoring and control insect pests in crops areas. The dispensing carriers of semiochemicals are typically made of non-degradable material, often petroleum derivatives such as butyl rubber, that become polluting waste after application. To develop a biodegradable and low-cost dispenser for semiochemicals, particles of CaCO3 and a CaCO3/Kraft lignin composite were synthesized using CO2 bubbling, characterized and evaluated for 30days as a dispenser of the limonene molecule, which is a common semiochemical in plants and also pheromone component is some insect species, such as the lesser mealworm Alphitobius diaperinus. Furthermore, limonene is volatile molecule that is easy to acquire and low-cost, which makes it an ideal semiochemical to evaluate the potential of the CaCO3 particles and CaCO3/Kraft lignin composite as a semiochemical dispenser for use in agriculture. The pure calcium carbonate I, pure calcium carbonate II, and composite I synthesized particles presented a larger specific surface area than the other composites. All the particles evaluated showed a slow limonene release rate between the 5th and 30th days evaluated, indicating the potential of these materials as pheromone dispensers. The composites with higher specific surface area, calcium carbonate II (19.5 m2/g) and composite I (23.1 m2/g), released a higher level of limonene during the 30days evaluated.

Synergistic Antimicrobial Activities of Limonene with Mineral Carriers in LDPE Films for Active Packaging Application

The integration of essential oils (EOs) into polymers to endow antimicrobial properties has received a lot of attention. EOs are remarkable in that they have broad antimicrobial activity from a natural source while also being volatile. Their volatility, on the other hand, makes high-temperature processing techniques difficult to incorporate into polymers. In this study, active films based on low-density polyethylene (LDPE) and limonene essential oil (LEO) were prepared and characterized. Before incorporation of LEO into LDPE, vacuum pulling method was used to load the LEO into five different mineral carriers. All Carrier-LEO complexes were added into LDPE using melt compounding. The goal is to analyze the potential use of these formulations to achieve prolonged antimicrobial film packaging. The halloysite nanotubes (HNTs), kaolinite (Kao), mesoporous silica nanoparticles (MSNs), zinc oxide nanoparticles (ZnONPs), and molecular sieve type 4A (Z4A) were used as mineral carriers for limonene. The functional characterizations including mechanical, thermal, optical, barrier, and antimicrobial properties as well as limonene release behavior from the LDPE composite films were investigated. As expected, free limonene molecules acted as a plasticizer in the LDPE matrix. Thermogravimetric analysis (TGA) showed 20-25% of the initial limonene content was retained against thermal degradation in compounding and film making steps and its release from the films was efficiently delayed. A decrease in optical and oxygen barrier properties, as well as elastic modulus and tensile strength, was obtained for all developed films compared with neat LDPE. Significant antibacterial activities of the films were observed against <i>Escherichia coli DH5-Alpha</i> (<i>E. coli)</i> as a model gram-negative bacterial species. Moreover, the obtained results and the short-term and long-term release studies indicated that both HNTs and the MSNs due to their strong synergistic interactions with limonene exhibited sustained release profiles of limonene from LDPE films. Thus, these new active polymer composites present promising features in controlling microbial contamination, rendering them as excellent candidates in active packaging applications.

Impact of Adsorbed Water on the Interaction of Limonene with Hydroxylated SiO2: Implications of π-Hydrogen Bonding for Surfaces in Humid Environments.

The indoor environment is a dynamic one with many variables impacting indoor air quality and indoor air chemistry. These include relative humidity (RH) and the presence of different surfaces. Although it has been suggested that the indoor concentrations of gas-phase compounds increase at higher relative humidity, because of displacement of these compounds from indoor surfaces, little is known from a molecular perspective about how RH and adsorbed water impact the adsorption of indoor relevant organic compounds such as limonene with indoor relevant surfaces. Herein, we investigate the effects of RH on the adsorption of limonene, a hydrophobic molecule, on hydroxylated SiO2 surfaces, a model for glass surfaces. Experimental data using infrared spectroscopy to directly measure limonene adsorption are combined with both force field-based molecular dynamics (MD) and ab initio molecular dynamics (AIMD) simulations to understand the competitive interactions between limonene, water, and the SiO2 surface. The spectroscopic data provide evidence that adsorbed limonene is not completely displaced by adsorbed water, even at high RH (∼80%) when the water layer coverage is close to three monolayers (MLs). These experimental data are supported by AIMD and MD simulations, which indicate that limonene is present at the adsorbed water interface but displaced from direct interactions with SiO2. This study shows that although some limonene can desorb from the surface, even at the highest RH, more than half the limonene remains adsorbed on the surface that can undergo continued surface reactivity. A complex network of π-hydrogen bonds, water-water hydrogen bonds, and SiO2-water hydrogen bonds explains these interactions at the air/adsorbed water/SiO2 interface that hold the hydrophobic limonene molecule at the interface. Importantly, these interactions are most likely present for a range of other systems involving organic compounds and solid surfaces at ambient relative humidity and may be important in a range of scientific areas, from sensor development to cultural heritage science.

Influence of Naturally Occurring Organic Surfactants on the Surface Tension of Sessile Droplets and Atmospheric Aerosols Measured with a Quasi-Elastic Laser Scattering System

Introduction Clouds are composed of atmospheric aerosols, micrometer sized aqueous droplets that are suspended in the air. These atmospheric aerosols play a key role in weather patterns and planet warming/cooling, making the understanding of their formation and propagation mechanisms highly important.[1] Despite the critical role aerosols play, there is still a fundamental lack in understanding of the processes that drive their formation and growth because there is no direct way to measure the surface tension of aerosol droplets in the atmosphere. In Köhler theory, which governs the formation and growth of aerosols, aerosol formation activity is driven by size and surface tension of the droplet, making an accurate measurement of aerosol surface tension integral to fully understanding cloud formation and evolution properties. In this study we utilize a new laser-based technique to measure the surface tension of micrometer sized droplets through droplet-surface capillary resonance and their response to naturally occurring pinene and limonene molecules exposed to the droplet surface. QELS Approach Thermal fluctuation drives the formation of capillary waves at a liquid interface, which can be observed with the quasi-elastic light scattering (QELS) technique (Figure 1). In our previous reports, the spontaneous resonance of thermally-induced capillary waves has been demonstrated on liquid surfaces with spatial confinement by a microchannel[2] and by a circular aperture.[3] Characteristic peaks corresponding to the capillary resonance appear in the QELS power spectrum. From the peak frequencies and spatial restriction conditions, surface tension can then be calculated.[4] Experimental Method In this work, micrometer sized aqueous droplets were generated by an ink-jet printer system and were immobilized in the path of a focused laser. Humid air was flown over the droplet to maintain size and shape, and QELS spectra collection/surface tension monitoring was started. Next, pinene or limonene were introduced to the air stream, interacting directly with the confined droplets. Surface tension properties were immediately affected by the presence of the hydrophobic molecules, causing the QELS spectra shape to change. The QELS spectra were monitored until equilibrium was reached. Finally, the trend in the surface tension of the droplets was calculated for each sample at various points during exposure to the surfactant molecules. Results and Conclusions In this study, we used the QELS method to probe the surface properties of micrometer sized droplets under a controlled atmosphere containing naturally occurring surfactant molecules. The results show that the presence of these hydrophobic molecules causes a clear suppression of the surface tension, which greatly impacts the aerosol droplet formation and growth properties, in turn impacting cloud formation and other related phenomena. The understanding of the influence of these molecules on the surface tension of aerosol droplets is expected to lead to enhanced knowledge on aerosol droplet formation mechanisms, which play a key role in cloud formation and weather phenomena.

Synthesis of new functional siloxane derivatives of limonene. Part I: Combination of hydrosilylation and hydrothiolation reactions

This article discusses the synthesis of mono- and difunctional siloxane derivatives of limonene obtained by hydrosilylation followed by hydrothiolation. It has been shown that, because of the different reactivity of the double bonds present in the limonene molecule, selective addition to one of them can be performed, which opens the possibility of obtaining various siloxane derivatives of limonene that can be used as initial monomers in the synthesis of polymers.

An Investigation into the Antibacterial Properties of Citrus and Plant Essential Oils

Langmuir Monolayers of dipalmitoylphosphatidylcholine (DPPC), dipalmitoylphosphatidylglycerol (DPPG), and E.coli lipid extract were used to investigate the antibacterial properties of essential oils, in particular sweet orange oil. DPPC served as the control membrane while DPPG served as the gram positive bacteria model and E.coli lipid extract was the gram negative bacteria model. The Langmuir Monolayer technique is useful for forming model cell membranes and allows for the analysis of the interactions between phospholipids and their molecular organization in the presence of another molecule. The main chemical in sweet orange oil, limonene, was found to disrupt phospholipid‐phospholipid interactions in all models except for DPPG simply because PG headgroups hydrogen bond with each other and there is no space for the hydrophobic limonene molecule. The largest disruption was observed for the E.coli extract lipids due to the unsaturated tails in these lipids resulting in less tight packing. Monolayers were seen in all three membrane systems to be destabilized as evidenced by the decrease in collapse pressure of the monolayer film but the E.coli lipid extract monolayer was the most affected in terms of fluidity as seen by the compression modulus. The antibacterial effects of orange oil on these systems is currently being compared to that of peppermint oil.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Limonene oxidation over Ti-MCM-41 and Ti-MWW catalysts with t-butyl hydroperoxide as the oxidant

This paper presents the method of limonene epoxidation over Ti-MCM-41 and Ti-MWW catalysts in the presence of t-butyl hydroperoxide as an oxidant. Natural limonene used in the epoxidation process was obtained via steam distillation (97% purity). The purpose of the research was to obtain the highest yield of 1,2-epoxylimonene, but the performed studies showed that the process of limonene epoxidation is more complex because in addition to epoxidation products (1,2-epoxylimonene and its diol which were formed usually in small amount) also the following oxygenated derivatives of limonene are formed: carvone, carveol, and perillyl alcohol (products of allylic oxidation (hydroxylation) at positions 6 and 7 in limonene molecule). Therefore, ultimately, the most favorable conditions for the limonene oxidation process were selected at the highest conversion of limonene and at high values of perillyl alcohol and carveol or one of these two products. Perillyl alcohol and carveol have found numerous applications in medicine, among others, therefore this direction seems to be the most beneficial. This also work presents the short characteristization of the titanium silicate Ti-MCM-41 and Ti-MWW catalysts used in the research, taking into account their structure, properties and applications are presented.

Preparation, properties and potential applications of a photocurable varnish with pleasant limonene smell

Abstract Photocurable materials which are obtained on the basis of urethane acrylate resins are often used in the industry for the production varnishes or protective coatings. The main disadvantage which is connected with the utilization of these varnishes is their unpleasant smell during the process of production and curing. This work presents the photocurable varnish which was obtained on the basis of aliphatic urethane acrylate and R-(+)-limonene. The utilization of this raw materials allows to obtain the smelling coatings. The aim of this work were the studies on the influence of limonene molecules on the mechanical properties of the UV-cured coatings. These studies showed that the coatings with limonene molecules retain their properties, and are characterized by the very good adhesion, cohesion and high gloss. These kinds of varnishes can be applied for preparation of appropriate protective coatings on the surface of wood, metals, and nail plates. These protective coatings have not only pleasure smell but also can have the bactericidal and fungicidal properties. The studies performed with Escherichia coli ATCC29425 and Candida albicans confirmed these properties.

Use of Limonene in Countercurrent Chromatography: A Green Alkane Substitute

Counter-current chromatography (CCC) is a preparative separation technique working with the two liquid phases of a biphasic liquid system. One phase is used as the mobile phase when the other, the stationary phase, is held in place by centrifugal fields. Limonene is a biorenewable cycloterpene solvent coming from orange peel waste. It was evaluated as a possible substitute for heptane in CCC separations. The limonene/methanol/water and heptane/methanol/water phase diagrams are very similar at room temperature. The double bonds of the limonene molecule allows for possible π-π interactions with solutes rendering limonene slightly more polar than heptane giving small differences in solute partition coefficients in the two systems. The 24% higher limonene density is a difference with heptane that has major consequences in CCC. The polar and apolar phases of the limonene/methanol/water 10/9/1 v/v have -0.025 g/cm(3) density difference (lower limonene phase) compared to +0.132 g/cm(3) with heptane (upper heptane phase). This precludes the use of this limonene system with hydrodynamic CCC columns that need significant density difference to retain a liquid stationary phase. It is an advantage with hydrostatic CCC columns because density difference is related to the working pressure drop: limonene allows one to work with high centrifugal fields and moderate pressure drop. Limonene has the capability to be a "green" alternative to petroleum-based solvents in CCC applications.

Addition of perfluoroalkanoic acids to (R)-(+)-limonene

Perfluoroalkanoic acids with different lengths of the perfluoroalkyl radical selectively add under mild conditions to the exocyclic double C=C of limonene to give the corresponding Markovnikov adducts, α-terpinyl perfluoroalkanoates. The reaction in the presence of sulfuric acid 0°C involves both double C=C bonds in the limonene molecule with formation of p-menthane-1,8-diyl bis(perfluoroalkanoates).

Intercalation of lecithins for preparation of layered nanohybrid materials and adsorption of limonene

The intercalation of biosurfactants (lysolecithin and lecithin) in layered clay mineral supports was investigated to assess the suitability of the resulting nanohybrid materials as flavor and fragrance delivery system. The protonated biosurfactant molecules (pH=2.3) were intercalated into the Na-montmorillonite, whereas the deprotonated biosurfactants (pH~12) were intercalated into Mg–Al layered double hydroxides. The amount of lysolecithin and lecithin bound to the layered adsorbents was estimated by measuring adsorption isotherms. The basal spacing obtained from X-ray diffraction measurements suggested that the molecules are arranged in parallel with the layers of montmorillonite, whereas in the case of layered double hydroxides, the adsorbed molecules are in a vertical position between the layers. The interaction of layered adsorbents and biosurfactants was further evidenced by infrared spectroscopy. The intercalated montmorillonite and LDH particles were then probed for their ability to intercalate limonene molecules. Only the lysolecithins modified samples adsorbed limonene. The theoretical sizes of molecules and their possible arrangement between the layers were modeled by HyperChem 7.0 molecular calculations to correlate the ability to bind the lecithins in the confined space of the layered materials.

Solvent-to-Polymer Chirality Transfer in Intramolecular Stack Structure

Solvent-to-polymer chirality transfer was examined using conjugated polymer with intramolecular stack structure (IaSS). When achiral poly(diphenylacetylene)s (PDPAs) dissolved in limonene, the solvent chirality was successfully transferred to the side phenyl stack structure, leading to intramolecular axial chirality. The phenyl–phenyl IaSS was under thermodynamic control to readily undergo asymmetric changes in chiral limonene, leading to optical activity in the isotropic structure between the main chain and resonant side phenyl rings. The axial chirality was significantly affected by the chain length and substitution position of the side alkyl groups. The longer alkyl chains and bulkier alkyl group prevented direct intermolecular interactions between the side phenyl rings and the chiral limonene molecules. PDPA with sterically congested, highly stable, and regulated IaSS was not favorable for efficient solvent-to-polymer chirality transfer.

Investigation in Influence of Types of Polypropylene Material on Diffusion by Using Molecular Dynamics Simulation

Polypropylene (PP) and its copolymers are widely used in food packaging films and containers. This paper investigates the diffusion of limonene as a low molar mass compound through three types of polypropylene materials (PP‐H, PP‐B and PP‐R) by using the molecular dynamics method, evaluates the influence of types of polypropylene material on the diffusion behaviour of limonene and reveals the diffusion mechanism. The diffusion coefficients of limonene in PP‐H, PP‐B and PP‐R are obtained at 313K and 353K. The accessible free volumes for polymers PP‐H, PP‐B and PP‐R are calculated by using the probe radius rp = 0.09, 0.11, 0.128 and 0.209 nm, respectively. The results suggest that not only the amount of accessible free volume in PP‐R cell model is larger than that of PP‐H and PP‐B but also the free volume in PP‐R connects together to form some larger free volume clusters. The movements of the limonene molecules through the PP‐H, PP‐B and PP‐R cell models at different simulation time suggest that for a long time the limonene molecules squirm slowly in the polymer cell rather than jumping and that the hopping diffusion is not suitable to explain the diffusion of limonene in polypropylene. The movement trajectories of the limonene molecules in PP‐R indicate that the movements of limonene in PP‐R are more active than that in PP‐H and PP‐B. The paper reveals the diffusion dynamics process and microscopic mechanism of small molecules from different types of polypropylene. Copyright © 2011 John Wiley &amp; Sons, Ltd.

Femtosecond characterization of vibrational optical activity of chiral molecules

Optical activity is the result of chiral molecules interacting differently with left versus right circularly polarized light. Because of this intrinsic link to molecular structure, the determination of optical activity through circular dichroism (CD) spectroscopy has long served as a routine method for obtaining structural information about chemical and biological systems in condensed phases. A recent development is time-resolved CD spectroscopy, which can in principle map the structural changes associated with biomolecular function and thus lead to mechanistic insights into fundamental biological processes. But implementing time-resolved CD measurements is experimentally challenging because CD is a notoriously weak effect (a factor of 10(-4)-10(-6) smaller than absorption). In fact, this problem has so far prevented time-resolved vibrational CD experiments. Here we show that vibrational CD spectroscopy with femtosecond time resolution can be realized when using heterodyned spectral interferometry to detect the phase and amplitude of the infrared optical activity free-induction-decay field in time (much like in a pulsed NMR experiment). We show that we can detect extremely weak signals in the presence of large achiral background contributions, by simultaneously measuring with a femtosecond laser pulse the vibrational CD and optical rotatory dispersion spectra of dissolved chiral limonene molecules. We have so far only targeted molecules in equilibrium, but it would be straightforward to extend the method for the observation of ultrafast structural changes such as those occurring during protein folding or asymmetric chemical reactions. That is, we should now be in a position to produce 'molecular motion pictures' of fundamental molecular processes from a chiral perspective.

Theoretical Study of Sum-Frequency Vibrational Spectroscopy Off Electronic Resonance on Limonene Chiral Liquids

The sum-frequency vibrational spectroscopy (SFVS) off electronic resonance on chiral liquids is analyzed using the approach of antisymmetric nonresonant vibrational Raman scattering tensor calculation, which is based on the direct Taylor expansion of electronic transition moments in vibrational normal coordinates. A single-excitation configuration interaction treatment is applied to compute the SFVS off electronic resonance for (R)-limonene molecules, and the model spectra compare favorably with experimental data. This direct evaluation approach may provide a method of computing antisymmetric nonresonant vibrational Raman polarizabilities and predicting and assigning the SFVS off electronic resonance on chiral liquids.

Ionic fragmentation of a natural product, limonene (C 10H 16), following core [C 1s] photoionization

Photoionization of the limonene [C 10H 16] molecule was studied for the first time following C 1s ionization, using synchrotron radiation and time-of-fight mass spectrometry. As a reference for further analysis of the photon induced fragmentation of the limonene molecule, the He(I) mass spectrum was also obtained. Previously unreported singly charged species have been observed at 310 eV: H +, C +, CH +, CH 2 +, CH 3 +. A close similarity has been observed between the high photon energy mass spectrum and the standard electron impact mass spectrum of limonene, obtained at 70 eV. In particular, the base peak [C 5H 8 +, m/ q = 68], known to result from a Retro Diels-Alder reaction, remains the same in both cases. Approximate values for the mean kinetic energy were determined for all ionic species.

The surface structure of catalysts activated with hydrogen donors as elucidated by multinuclear solid-state NMR

1H, 27Al and 31P MAS, and 13C and 29Si CP/MAS NMR spectroscopies, were used to characterize catalysts of Pd supported on various solids including SiO 2, AlPO 4 and Mg 3(PO 4) 2 that were activated with the chiral hydrogen-donor limonene. The above-mentioned techniques were used to check for the formation of an organopalladium complex between Pd 2+ atoms and the olefin bonds in the limonene molecule on the catalyst surface. The results are compared with those obtained for catalysts activated in a hydrogen stream.