Name: ultrasonic-assisted preparation of biodiesel products from vegetable oils
Uploaded: 2024-04-19T14:40:00.000+00:00
Duration: 4 min 40 s
Description: Read this Scientific Article Protocol about Author Spotlight: Employing Green-Chemistry Principles for Safe and Sustainable Synthesis of Biodiesels at JoVE.com

The work was supported by Author YL&#39;s start-up fund and Pedagogy Enhancement Award (PEA) at California State University, Sacramento.

1. Oil source and preparation
<ol>
	<li>Add 2.0 mL of HPLC-grade methanol into a 15 mL centrifuge tube. 
	CAUTION: Methanol is a highly flammable liquid. It is toxic if swallowed, in contact with skin, or if inhaled, and it causes damage to the eyes. Ensure to wear personal protective equipment (PPE) when working with methanol and use it in the fume hood.</li>
	<li>Add one pellet of KOH (~0.10 g) to the centrifuge tube and dissolve the KOH solid using the ultrasonic cleaner (40 kHz) by just turning on the ultrasonic. 
	CAUTION: KOH is harmful if swallowed. It causes severe skin burns, eye damage, and serious eye damage. Ensure to wear PPE when working with this substance. 
	NOTE: For optimal results, place the centrifuge tube inside a beaker filled with water and then position the beaker within the ultrasonic bath. This immersed configuration guarantees thorough exposure of the reaction mixture to the ultrasonic irradiation, maximizing its effectiveness.</li>
</ol>
2. Transesterification process
<ol>
	<li>Add 8.0 mL of extra virgin olive oil to the centrifuge tube.</li>
	<li>Cap and close the centrifuge tube tight and shake the centrifuge tube vigorously to mix the oil and the potassium methoxide&#160;solution. 
	NOTE: Keep the centrifuge cap tight when shaking the centrifuge tube.</li>
	<li>Loosen the cap and put the centrifuge tube into the ultrasonic bath. Turn on the ultrasonic bath for 1 min.</li>
	<li>After the first 1 min, close the centrifuge cap tight and shake the centrifuge tube vigorously again.</li>
	<li>Loosen the cap and put the reaction mixture into the ultrasonic bath for another 14 min.</li>
	<li>Transfer the reaction mixture to a separatory funnel and drain the bottom glycerin layer.</li>
	<li>Wash the top layer with 15 mL of saturated NaCl solution 3x, to wash the excess methanol and residual catalyst out of the ester. Ensure the pH of the final washing is neutral by testing with a pH paper.</li>
	<li>Transfer the top biodiesel&#160;layer into a dry, clean vial, add anhydrous&#160;Na2SO4&#160;to the vial, swirl the mixture, and let the&#160;mixture stand for about 15 min till the biodiesel&#160;is clear. Use the clear biodiesel product for&#160;characterization.</li>
</ol>
3. Characterization of biodiesel
<ol>
	<li>Fourier-transform infrared (FT-IR) analysis
	<ol>
		<li>Record the FT-IR spectra across a wide range of 4000-400 cm-1. Measure each sample by co-adding 16 scans at a resolution of 4 cm-1. Perform background subtraction by acquiring a fresh air spectrum before each sample scan. This is to ensure accurate baseline correction and minimized sample contamination. Before each new sample, clean the ATR plate using methanol then dry with lint-free wipes.</li>
	</ol>
	</li>
	<li>Proton nuclear magnetic resonance (1H NMR) analysis
	<ol>
		<li>To analyze the chemical composition of the biodiesel product, record the nuclear magnetic resonance (NMR) spectra of biodiesel and extra virgin olive oil on a 500 MHz NMR spectrometer at room temperature. Utilizing a high-resolution 5 mm double gradient probe, prepare each sample by dissolving 50 mg of the sample in 0.7 mL of deuterated chloroform (CDCl3) containing 0.05% tetramethylsilane (TMS) as an internal standard. Acquire 1H NMR spectra using the TOPSPIN program with 16 scans and referenced to the TMS standard at 0.0 ppm. 
		&#8203;CAUTION: CDCl3 is harmful if swallowed and toxic if inhaled. It causes skin irritation and serious eye irritation. Wear PPE when working with this substance.</li>
	</ol>
	</li>
	<li>Viscosity analysis
	<ol>
		<li>Prepare two 5.75 inch glass Pasteur pipettes and one pipette pump.</li>
		<li>Make two marks on each pipette with a pen. The top mark is on the body of the pipette, and the second mark is on the narrow stem, approximately 2 cm up from the tip.</li>
		<li>Use a pipette pump to fill the pipette with extra virgin olive oil with the meniscus at the top mark.</li>
		<li>Remove the pipette pump and start the stopwatch. Stop the stopwatch as extra virgin olive oil reaches the lower mark.</li>
		<li>Repeat steps 3.3.3 and 3.3.4 with biodiesel product instead of extra virgin olive oil.</li>
		<li>Determine the relative viscosities of biodiesel versus the extra virgin olive oil by timing their passage through a glass pipette. 
		Relative Viscosity = (oil time)/(biodiesel time).</li>
	</ol>
	</li>
	<li>Flammability tests
	<ol>
		<li>Immerse a cotton string of approximately 2 cm in length into biodiesel and another cotton string into extra virgin olive oil. Ensure complete saturation of the string with the respective liquid. Place the coated cotton strings on aluminum foil.</li>
		<li>In a designated laboratory area, away from flammable solvents, assess the ease of igniting each cotton string and observe the quality of the flame produced. Determine if one cotton string ignites more readily than the other. Evaluate which liquid exhibits superior wicking capabilities and which sustains a stronger burn.</li>
	</ol>
	</li>
</ol>

Biodiesel Synthesis by Ultrasonic-Assisted Transesterification of Vegetable Oils

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The authors have nothing to disclose.

In this demonstration, an ultrasonic assisted method of base-catalyzed production of biodiesel is elucidated for optimal efficacy. For optimal results, the centrifuge tube should be placed inside a beaker filled with water and then the beaker should be placed within the ultrasonic bath. This immersed configuration guarantees thorough exposure of the reaction mixture to the ultrasonic treatment, maximizing its effectiveness. If desired, a centrifuge rack can also be used to replace the beaker inside the ultrasonic bath, which can further reduce the noise of ultrasonication.
Proper solvent selection is another critical component for the synthesis of biodiesel by ultrasonic-assisted synthesis. Although both methanol and ethanol are green solvents21 and can be used to produce biodiesel, compared to ethanol, methanol offers several advantages, including cost-effectiveness, faster reaction times, efficient glycerin separation, and friendly purity assessment using 1H NMR22. Therefore, methanol is used in this demonstration. Moreover, the biodiesel product resulted from methanol is easier to characterize using H1 NMR5.
Water poses a significant challenge in the transesterification of vegetable oil, hindering both catalyst efficiency and biodiesel purity. Excess water triggers hydrolysis, converting valuable biodiesel into problematic free fatty acids that react with the alkaline catalyst, forming troublesome soap. This soap impedes separation and purification, reduces catalyst activity, and ultimately lowers biodiesel yield. However, the reaction mixture in a closed system will cause a lower yield of biodiesel. Therefore, the cap of the centrifuge tube needs to be loosened under ultrasonic treatment.
The ultrasonic-assisted method is advantageous over the conventional heating methods because biodiesel can be synthesized accurately, precisely, and quickly at room temperature under atmospheric pressure. In this method, biodiesel is synthesized under ambient temperature and atmospheric pressure, which is more energy efficient and safer than conventional heating methods. Therefore, the ultrasonic-assisted method is a greener method in comparison to conventional heating method. Due to its environmental friendliness, energy efficiency, and short reaction time under ambient conditions, biodiesel can be prepared within 15 min using the ultrasonic-assisted method. This method is also applicable for other vegetable oils, such as soybean oil, corn oil, canola oil, peanut oil, and olive oil. The results have been reported in our previous publication5. These vegetable oils are commercially available and easily accessible, allowing for wider adoption of the ultrasonic-assisted method.
Different ultrasonic baths (40 kHz) can be used, including low-cost ultrasonic cleaners or ultrasonic jewelry cleaners, although the reaction time may vary. Compared with an ultrasonic probe, an ultrasonic bath has one frequency, which is the limitation of this method. Because the reaction time is short and multiple reactions can be run simultaneously in the ultrasonic bath, the ultrasonic-assisted method can also be used in teaching laboratory courses as a good example to introduce to students the application of 12 principles of green chemistry such as the use of renewable feedstocks, design for energy efficiency, inherently safer chemistry for accident prevention, and catalysis.
In conclusion, an ultrasonic-assisted transesterification method was introduced for the preparation of pure biodiesel from commercially available vegetable oils at room temperature and atmospheric pressure. Compared to traditional heating methods, ultrasonic irradiation offers significant advantages in oil transesterification: shorter reaction times, decreased molar ratios of alcohol to oil, up to 50% lower energy consumption, and increased reaction rates. This efficient process leverages ultrasound irradiation to achieve effective energy distribution within the reaction mixture, leading to superior performance17,23. Moreover, it is advantageous to run small-scale reactions using low-cost ultrasonic baths; therefore, ultrasonic baths as the ultrasound irradiation source can be easily and widely adopted in research and teaching laboratories.

Biodiesel, derived from common, plant-based oils and fats, emerges as a sustainable solution to mitigate reliance on petroleum1. This renewable substitute showcases reduced greenhouse gas emissions, notably carbon dioxide, while relying on sustainable resources. Furthermore, biodiesel presents distinct advantages over petroleum diesel, characterized by its sulfur-free composition, non-toxic nature, and biodegradability. As an alternative to conventional fossil fuels, biodiesel aligns with the United Nations&#39; (UN&#39;s) Net Zero policy by reducing our dependence on non-renewable fossil fuels and mitigating the adverse effects of climate change. Biodiesel offers a promising path to meeting current energy needs, making it a powerful choice for a greener future2.
The predominant method used for biodiesel production involves transesterification, a chemical process where triglycerides found in oils and fats react with an alcohol, typically methanol or ethanol, in the presence of a catalyst under elevated temperature conditions1,2,3,4.&#160;This reaction yields fatty acid alkyl esters, the principal component of biodiesel. Various types of vegetable oils serve as primary feedstocks for biodiesel production, including both edible5 (e.g., extra virgin olive oil and corn oil) and non-edible oils6,7,8 (e.g., caper seed oil), as well as waste oils9. Methanol is most commonly used for this transesterification process as it is a relatively inexpensive alcohol. Additionally, an array of catalysts such as sulfuric acid, phosphoric acid, potassium hydroxide, sodium hydroxide, or enzymes like lipase can be used to expedite the transesterification process1,2,3,4. Traditionally, the reaction mixture is heated under reflux for prolonged periods, typically 30 min or more. Heating is not as energy efficient as ultrasonication while also posing safety risks5. Consequently, there is a need for a safer, faster, and more energy efficient transesterification process.
Ultrasound irradiation emerges as a superior alternative to conventional energy sources such as heat, light, and electricity, primarily due to the phenomenon of acoustic cavitation10. This phenomenon, characterized by the formation, expansion, and violent collapse of bubbles, generating localized hotspots with temperatures reaching approximately 5000 K and pressures of 1000 atm. Such extreme conditions, coupled with rapid heating and cooling rates (over 1010 K/s), furnish the requisite energy for a wide array of chemical reactions to occur efficiently at room temperature, including those previously deemed unattainable by conventional means10. Ultrasonic-assisted synthesis is rapidly gaining ground across diverse research areas. Notably, interest in ultrasonic-assisted synthesis in organic synthesis and solid-state materials is driven by its environmentally friendly nature, energy efficiency, and abbreviated reaction times under ambient conditions5,11,12,13,14,15,16.&#160;A prompt and effective technique is introduced here for secure ultrasonic-assisted transesterification of vegetable oils using an alkaline catalyst yielding pure biodiesel products within a short time frame. While extra virgin olive oil serves as the demonstration medium in this study, it is imperative to note that the ultrasonic method holds applicability to a spectrum of vegetables oils5,17.

<table><tbody><tr><td>Chloroform-d</td><td>Fisher Scientific</td><td>865-49-6</td><td>&amp;bull; Harmful if swallowed.&lt;br/&gt; &amp;bull; Causes skin irritation.&lt;br/&gt; &amp;bull; Causes serious eye irritation.&lt;br/&gt; &amp;bull; Toxic if inhaled.&lt;br/&gt; &amp;bull; Suspected of causing cancer.&lt;br/&gt; &amp;bull; Suspected of damaging fertility or the unborn child.&lt;br/&gt; &amp;bull; Causes damage to organs through prolonged or repeated exposure</td></tr><tr><td>Heated Ultrasonic Baths, Digital, Branson Ultrasonic</td><td>Branson&amp;nbsp;</td><td>89375-492</td><td></td></tr><tr><td>Methanol</td><td>Fisher Scientific Company</td><td>67-56-1</td><td>Highly flammable liquid and vapor. Toxic if swallowed, in contact with skin or if inhaled. Causes damage to organs (Eyes).</td></tr><tr><td>Potassium hydroxide&amp;nbsp;</td><td>Fisher Scientific Company</td><td>1310-58-3</td><td>May be corrosive to metals. Harmful if swallowed. Causes severe skin burns and eye damage. Causes serious eye damage</td></tr><tr><td>Sodium chloride</td><td>Sigma-Aldrich</td><td>7647-14-5</td><td>Not hazardous</td></tr><tr><td>Vegetable oils</td><td></td><td></td><td>A commonly consumed food with a long history of safe use in pesticides.&amp;nbsp;</td></tr></tbody></table>

ultrasonic-assisted preparation of biodiesel products from vegetable oils

Utilizing vegetable oil as a sustainable feedstock, this study presents an innovative approach to ultrasonic-assisted transesterification for biodiesel synthesis. This alkaline-catalyzed procedure harnesses ultrasound as a potent energy input, facilitating the rapid conversion of extra virgin olive oil into biodiesel. In this demonstration, the reaction is run in an ultrasonic bath under ambient conditions for 15 min, requiring a 1:6 molar ratio of extra virgin olive oil to methanol and a minimum amount of KOH as the catalyst. The physiochemical properties of biodiesel are also reported. Emphasizing the remarkable advantages of ultrasonic-assisted transesterification, this method demonstrates notable reductions in reaction and separation times, achieving near-perfect purity (~100%), high yields, and negligible waste generation. Importantly, these benefits are achieved within a framework that prioritizes safety and environmental sustainability. These compelling findings underscore the effectiveness of this approach in converting vegetable oil into biodiesel, positioning it as a viable option for both research and practical applications.

In this demonstration, the transesterification reaction of extra virgin olive oil and methanol, catalyzed by KOH, produces biodiesel at room temperature in an ultrasonic bath (Figure 1)5. The starting materials in the centrifuge tube show the reactants are immiscible and divided into two layers as seen in Figure 2A. The upper layer is a mixture of methanol and KOH while the lower layer is composed of extra virgin olive oil. To promote homogenization, a brief pre-mixing of the reactants is recommended before subjecting the centrifuge tube to ultrasonic agitation.
After 1 min in the ultrasonic bath, the reaction mixture undergoes noticeable homogenization as seen in Figure 2B. After another 14 min in the ultrasonic bath, product separation occurs with the upper layer comprising biodiesel products and the lower layer containing glycerol esters as shown in Figure 2C. Allowing the mixture to settle for a few minutes further improves separation, as shown in Figure 2D. Hence, the ultrasonic-assisted transesterification reaction efficiently yields biodiesel at room temperature and under atmospheric pressure within a short time. Moreover, the reaction facilitates accelerated separation of biodiesel from the glycerin layer for facile work-up. The biodiesel products can be further purified by separation in a separatory funnel and subsequent washing with saturated NaCl solutions. Characterization of the biodiesel product can be accomplished through 1H-NMR analysis to confirm the successful synthesis of biodiesel.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/66689/66689fig01.jpg" /> 
Figure 1: Synthesis of biodiesel from vegetable oils via transesterification reaction. The image shows the synthesis steps described here.))) represents ultrasonic treatment; r.t. represents room temperature. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/66689/66689fig01large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/66689/66689fig02.jpg" /> 
Figure 2: Reaction mixture. The images show the reaction mixture&#160;(A)&#160;at time 0 min, (B)&#160;after 1 min of ultrasonic treatment, (C) just after finishing (after 15 min of ultrasonic treatment), and (D)&#160;at&#160;5 min after the reaction finished. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/66689/66689fig02large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
The FT-IR spectra of the extra virgin olive oil (Figure 3A) and&#160;biodiesel (Figure 3B) are analyzed to confirm the production of biodiesel. The peak at 1435 cm-1 is present in the biodiesel showing CH3 asymmetric bending, while this peak is absent in the extra virgin olive oil. The peak at 1195 cm-1 shows the O-CH3 stretching is present in biodiesel, but this peak is absent in extra virgin olive oil. Three peaks are present in both extra virgin olive oil and biodiesel: the peaks between 2800-3000 cm-1 show the CH2 stretching and the asymmetric CH3 and CH2 stretching, and the peak between 1700-1800 cm-1 shows the stretch of C=O. A band at 721-723 cm-1 indicates a Z (cis) double bond in the hydrocarbon chain of the biodiesel. (Z)-Unsaturation lowers the melting point of the product. The results are consistent to previous literature18.
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/66689/66689fig03.jpg" /> 
Figure 3: FT-IR spectrum. The FT-IR spectrum measured from 4000-400 cm-1 for (A) extra virgin olive oil and (B) biodiesel. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/66689/66689fig03large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
For 1H NMR results, the extra virgin olive oil contains a multiplet at &#948; = 4.1-4.3 ppm and a multiplet at &#948; = 5.2-5.3 ppm for its glyceryl protons (Figure 4A). The biodiesel product exhibits an absence of glyceryl protons, displaying a singlet at &#948; = 3.67 ppm for the methyl protons within the methyl ester (Figure 4B). The peaks are consistent to previous literature19,20. This singlet differs from the CH3 singlet (&#948; = 3.49 ppm) observed in MeOH. Based on the 1H NMR findings, it is evident that the ultrasonic-assisted method can produce biodiesel with a purity of close to 100%.
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/66689/66689fig04.jpg" /> 
Figure 4: 1H NMR spectrum. The 1H NMR (500 MHz) spectrum in CDCl3 of (A) extra virgin olive oil with the corresponding assignment of the major peaks of the glycerol unit and the fatty acid chains and (B) biodiesel with corresponding assignment of the major peaks of methyl ester and the fatty acid chains. Spectra demonstrate the different functional groups in the vegetable oil and biodiesel and the purity of the biodiesel product. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/66689/66689fig04large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
Biodiesel which has a viscosity closer to that of petroleum diesel is about 8x less viscous than extra virgin olive oil. Extra virgin olive oil with its 10x viscosity disadvantage, makes it impractical for fuel systems.
When tested for flammability, cotton string soaked in biodiesel ignited faster and burned more intensely than the one soaked in extra virgin olive oil. This suggests biodiesel&#39;s potential as a diesel fuel alternative.

Read this Scientific Article Protocol about Author Spotlight: Employing Green-Chemistry Principles for Safe and Sustainable Synthesis of Biodiesels at JoVE.com

Author Spotlight: Employing Green-Chemistry Principles for Safe and Sustainable Synthesis of Biodiesels

A safe ultrasonic-assisted transesterification method for vegetable oils using an alkaline catalyst is presented here. The method is rapid and efficient for preparing pure biodiesel products.

Ultrasonic-Assisted Preparation of Biodiesel Products from Vegetable Oils

Utilizing vegetable oil as a sustainable feedstock, this study presents an innovative approach to ultrasonic-assisted transesterification for biodiesel ...

ultrasonic-assisted-preparation-biodiesel-products-from-vegetable

Nanyang Technological University

Research

JoVE Journal

Chemistry

982 Views.  California State University, Sacramento. Ons onderzoek introduceert een milieuvriendelijke en veilige methode om biodiesel te produceren via een ultrasone omesteringsreactie. We proberen een antwoord te vinden op de vraag hoe we groene chemieprincipes kunnen toepassen en ultrasone energie kunnen gebruiken om reacties te bevorderen. We gebruiken momenteel ultrasone technologieën om de duurzaamheid van reacties te verbeteren, volgens de principes van groene chemie.We hebben een veilige, snelle en efficiënte methode ontwikkeld...

Video: Auteur in de schijnwerpers: Gebruik van groene chemieprincipes voor veilige en duurzame synthese van biodiesels

Biomass Conversion to Produce Hydrocarbon Liquid Fuel Via Hot-vapor Filtered Fast Pyrolysis and Catalytic Hydrotreating

Lignocellulosic biomass conversion to produce biofuels has received significant attention because of the quest for a replacement for fossil fuels. Among the various thermochemical and biochemical routes, fast pyrolysis followed by catalytic hydrotreating is considered to be a promising near-term opportunity. This paper reports on experimental methods used 1) at the National Renewable Energy Laboratory (NREL) for fast pyrolysis of lignocellulosic biomass to produce bio-oils in a fluidized-bed reactor and 2) at Pacific Northwest National Laboratory (PNNL) for catalytic hydrotreating of bio-oils in a two-stage, fixed-bed, continuous-flow catalytic reactor. The configurations of the reactor systems, the operating procedures, and the processing and analysis of feedstocks, bio-oils, and biofuels are described in detail in this paper. We also demonstrate hot-vapor filtration during fast pyrolysis to remove fine char particles and inorganic contaminants from bio-oil. Representative results showed successful conversion of biomass feedstocks to fuel-range hydrocarbon biofuels and, specifically, the effect of hot-vapor filtration on bio-oil production and upgrading. The protocols provided in this report could help to generate rigorous and reliable data for biomass pyrolysis and bio-oil hydrotreating research.

Experimental methods for fast pyrolysis of lignocellulosic biomass to produce bio-oils and for the catalytic hydrotreating of bio-oils to produce fuel range hydrocarbons are presented. Hot-vapor filtration during fast pyrolysis to remove fine char particles and inorganic contaminants from bio-oil was also assessed.

Lignocellulosic biomass conversion to produce biofuels has received significant attention because of the quest for a replacement for fossil fuels. Among ...

Biochemistry

Experimental Protocol for Biodiesel Production with Isolation of Alkenones as Coproducts from Commercial Isochrysis Algal Biomass

The need to replace petroleum fuels with alternatives from renewable and more environmentally sustainable sources is of growing importance. Biomass-derived biofuels have gained considerable attention in this regard, however first generation biofuels from edible crops like corn ethanol or soybean biodiesel have generally fallen out of favor. There is thus great interest in the development of methods for the production of liquid fuels from domestic and superior non-edible sources. Here we describe a detailed procedure for the production of a purified biodiesel from the marine microalgae Isochrysis. Additionally, a unique suite of lipids known as polyunsaturated long-chain alkenones are isolated in parallel as potentially valuable coproducts to offset the cost of biodiesel production. Multi-kilogram quantities of Isochrysis are purchased from two commercial sources, one as a wet paste (80% water) that is first dried prior to processing, and the other a dry milled powder (95% dry). Lipids are extracted with hexanes in a Soxhlet apparatus to produce an algal oil (&#34;hexane algal oil&#34;) containing both traditional fats (i.e., triglycerides, 46-60% w/w) and alkenones (16-25% w/w). Saponification of the triglycerides in the algal oil allows for separation of the resulting free fatty acids (FFAs) from alkenone-containing neutral lipids. FFAs are then converted to biodiesel (i.e., fatty acid methyl esters, FAMEs) by acid-catalyzed esterification while alkenones are isolated and purified from the neutral lipids by crystallization. We demonstrate that biodiesel from both commercial Isochrysis biomasses have similar but not identical FAME profiles, characterized by elevated polyunsaturated fatty acid contents (approximately 40% w/w). Yields of biodiesel were consistently higher when starting from the Isochrysis wet paste (12% w/w vs. 7% w/w), which can be traced to lower amounts of hexane algal oil obtained from the powdered Isochrysis product.

Experimental Protocol for Biodiesel Production with Isolation of Alkenones as Coproducts from Commercial Isochrysis Algal Biomass

Detailed methods are presented for the production of biodiesel along with the co-isolation of alkenones as valuable coproducts from commercial Isochrysis microalgae.

The need to replace petroleum fuels with alternatives from renewable and more environmentally sustainable sources is of growing importance. ...

Environment

Preparation of Carbon Nanosheets at Room Temperature

Amphiphilic molecules equipped with a reactive, carbon-rich "oligoyne" segment consisting of conjugated carbon-carbon triple bonds self-assemble into defined aggregates in aqueous media and at the air-water interface. In the aggregated state, the oligoynes can then be carbonized under mild conditions while preserving the morphology and the embedded chemical functionalization. This novel approach provides direct access to functionalized carbon nanomaterials. In this article, we present a synthetic approach that allows us to prepare hexayne carboxylate amphiphiles as carbon-rich siblings of typical fatty acid esters through a series of repeated bromination and Negishi-type cross-coupling reactions. The obtained compounds are designed to self-assemble into monolayers at the air-water interface, and we show how this can be achieved in a Langmuir trough. Thus, compression of the molecules at the air-water interface triggers the film formation and leads to a densely packed layer of the molecules. The complete carbonization of the films at the air-water interface is then accomplished by cross-linking of the hexayne layer at room temperature, using UV irradiation as a mild external stimulus. The changes in the layer during this process can be monitored with the help of infrared reflection-absorption spectroscopy and Brewster angle microscopy. Moreover, a transfer of the carbonized films onto solid substrates by the Langmuir-Blodgett technique has enabled us to prove that they were carbon nanosheets with lateral dimensions on the order of centimeters.

We present the synthesis of an amphiphilic hexayne and its use in the preparation of carbon nanosheets at the air-water interface from a self-assembled monolayer of these reactive, carbon-rich molecular precursors.

Amphiphilic molecules equipped with a reactive, carbon-rich "oligoyne" segment consisting of conjugated carbon-carbon triple bonds self-assemble into ...

A Direct, Early Stage Guanidinylation Protocol for the Synthesis of Complex Aminoguanidine-containing Natural Products

The guanidine functional group, displayed most prominently in the amino acid arginine, one of the fundamental building blocks of life, is an important structural element found in many complex natural products and pharmaceuticals. Owing to the continual discovery of new guanidine-containing natural products and designed small molecules, rapid and efficient guanidinylation methods are of keen interest to synthetic and medicinal organic chemists. Because the nucleophilicity and basicity of guanidines can affect subsequent chemical transformations, traditional, indirect guanidinylation is typically pursued. Indirect methods commonly employ multiple protection steps involving a latent amine precursor, such as an azide, phthalimide, or carbamate. By circumventing these circuitous methods and employing a direct guanidinylation reaction early in the synthetic sequence, it was possible to forge the linear terminal guanidine containing backbone of clavatadine A to realize a short and streamlined synthesis of this potent factor XIa inhibitor. In practice, guanidine hydrochloride is elaborated with a carefully constructed protecting array that is optimized to survive the synthetic steps to come. In the preparation of clavatadine A, direct guanidinylation of a commercially available diamine eliminated two unnecessary steps from its synthesis. Coupled with the wide variety of known guanidine protecting groups, direct guanidinylation evinces a succinct and efficient practicality inherent to methods that find a home in a synthetic chemist&#39;s toolbox.

Here, we present a protocol for direct, early stage guanidinylation that enables rapid total synthesis of aminoguanidine-containing small organic molecules. An advanced synthetic intermediate used in the synthesis of a blood coagulation factor XIa inhibitor was prepared using this protocol.

The guanidine functional group, displayed most prominently in the amino acid arginine, one of the fundamental building blocks of life, is an important ...

Facile Preparation of 4-Substituted Quinazoline Derivatives

Reported in this paper is a very simple method for direct preparation of 4-substituted quinazoline derivatives from a reaction between substituted 2-aminobenzophenones and thiourea in the presence of dimethyl sulfoxide (DMSO). This is a unique complementary reaction system in which thiourea undergoes thermal decomposition to form carbodiimide and hydrogen sulfide, where the former reacts with 2-aminobenzophenone to form 4-phenylquinazolin-2(1H)-imine intermediate, whilst hydrogen sulfide reacts with DMSO to give methanethiol or other sulfur-containing molecule which then functions as a complementary reducing agent to reduce 4-phenylquinazolin-2(1H)-imine intermediate into 4-phenyl-1,2-dihydroquinazolin-2-amine. Subsequently, the elimination of ammonia from 4-phenyl-1,2-dihydroquinazolin-2-amine affords substituted quinazoline derivative. This reaction usually gives quinazoline derivative as a single product arising from 2-aminobenzophenone as monitored by GC/MS analysis, along with small amount of sulfur-containing molecules such as dimethyl disulfide, dimethyl trisulfide, etc. The reaction usually completes in 4-6 hr at 160 &#186;C in small scale but may last over 24 hr when carried out in large scale. The reaction product can be easily purified by means of washing off DMSO with water followed by column chromatography or thin layer chromatography.

A protocol for facile preparation of 4-substituted quinazoline derivatives from 2-aminobenzophenones, thiourea and dimethyl sulfoxide is presented.

Reported in this paper is a very simple method for direct preparation of 4-substituted quinazoline derivatives from a reaction between substituted ...

Preparation of Biopolymer Aerogels Using Green Solvents

Although the first reports on aerogels made by Kistler1 in the 1930s dealt with aerogels from both inorganic oxides (silica and others) and biopolymers (gelatin, agar, cellulose), only recently have biomasses been recognized as an abundant source of chemically diverse macromolecules for functional aerogel materials. Biopolymer aerogels (pectin, alginate, chitosan, cellulose, etc.) exhibit both specific inheritable functions of starting biopolymers and distinctive features of aerogels (80-99% porosity and specific surface up to 800 m2/g). This synergy of properties makes biopolymer aerogels promising candidates for a wide gamut of applications such as thermal insulation, tissue engineering and regenerative medicine, drug delivery systems, functional foods, catalysts, adsorbents and sensors. This work demonstrates the use of pressurized carbon dioxide (5 MPa) for the ionic cross linking of amidated pectin into hydrogels. Initially a biopolymer/salt dispersion is prepared in water. Under pressurized CO2 conditions, the pH of the biopolymer solution is lowered to 3 which releases the crosslinking cations from the salt to bind with the biopolymer yielding hydrogels. Solvent exchange to ethanol and further supercritical CO2 drying (10 - 12 MPa) yield aerogels. Obtained aerogels are ultra-porous with low density (as low as 0.02 g/cm3), high specific surface area (350 - 500 m2/g) and pore volume (3 - 7 cm3/g for pore sizes less than 150 nm).

A new way for the production of biopolymer-based aerogels by carbon dioxide (CO2) induced gelation is shown. The technique utilizes pressurized carbon dioxide (5 MPa) for the production of biopolymer hydrogels and supercritical CO2 (12 MPa) to convert gels into aerogels. The only solvents needed besides CO2 are water and ethanol.

Although the first reports on aerogels made by Kistler1 in the 1930s dealt with aerogels from both inorganic oxides (silica and others) and biopolymers ...

Laboratory Production of Biofuels and Biochemicals from a Rapeseed Oil through Catalytic Cracking Conversion

The work is based on a reported study which investigates the processability of canola oil (bio-feed) in the presence of bitumen-derived heavy gas oil (HGO) for production of transportation fuels through a fluid catalytic cracking (FCC) route. Cracking experiments are performed with a fully automated reaction unit at a fixed weight hourly space velocity (WHSV) of 8 hr-1, 490-530 &#176;C, and catalyst/oil ratios of 4-12 g/g. When a feed is in contact with catalyst in the fluid-bed reactor, cracking takes place generating gaseous, liquid, and solid products. The vapor produced is condensed and collected in a liquid receiver at -15 &#176;C. The non-condensable effluent is first directed to a vessel and is sent, after homogenization, to an on-line gas chromatograph (GC) for refinery gas analysis. The coke deposited on the catalyst is determined in situ by burning the spent catalyst in air at high temperatures. Levels of CO2 are measured quantitatively via an infrared (IR) cell, and are converted to coke yield. Liquid samples in the receivers are analyzed by GC for simulated distillation to determine the amounts in different boiling ranges, i.e., IBP-221 &#176;C (gasoline), 221-343 &#176;C (light cycle oil), and 343 &#176;C+ (heavy cycle oil). Cracking of a feed containing canola oil generates water, which appears at the bottom of a liquid receiver and on its inner wall. Recovery of water on the wall is achieved through washing with methanol followed by Karl Fischer titration for water content. Basic results reported include conversion (the portion of the feed converted to gas and liquid product with a boiling point below 221 &#176;C, coke, and water, if present) and yields of dry gas (H2-C2's, CO, and CO2), liquefied petroleum gas (C3-C4), gasoline, light cycle oil, heavy cycle oil, coke, and water, if present.

This paper presents an experimental method to produce biofuels and biochemicals from canola oil mixed with a fossil-based feed in the presence of a catalyst at mild temperatures. Gaseous, liquid, and solid products from a reaction unit are quantified and characterized. Conversion and individual product yields are calculated and reported.

The work is based on a reported study which investigates the processability of canola oil (bio-feed) in the presence of bitumen-derived heavy gas oil ...

Ultrasonic-Assisted Extraction of Cannabidiolic Acid from Cannabis Biomass

Industrial hemp (Cannabis spp.) has many compounds of interest with potential medical benefits. Of these compounds, cannabinoids have come to the center of attention, specifically acidic cannabinoids. The focus is turning toward acidic cannabinoids due to their lack of psychotropic activity. Cannabis plants produce acidic cannabinoids with hemp plants producing low levels of psychotropic cannabinoids. As such, utilization of hemp for acidic cannabinoid extraction would eliminate the need for decarboxylation prior to extraction as a source for the cannabinoids. The use of solvent-based extraction is ideal for obtaining acidic cannabinoids as their solubility in solvents such as supercritical CO2 is limited due to the high pressure and temperature required to reach their solubility constants. An alternative method designed to increase solubility is ultrasonic-assisted extraction. In this protocol, the impact of solvent polarity (acetonitrile 0.46, ethanol 0.65, methanol 0.76, and water 1.00) and concentration (20%, 50%, 70%, 90%, and 100%) on ultrasonic-assisted extraction efficiency has been examined. Results show that water was the least effective and acetonitrile was the most effective solvent examined. Ethanol was further examined since it has the lowest toxicity and is generally regarded as safe (GRAS). Surprisingly, 50% ethanol in water is the most effective ethanol concentration for extracting the highest amount of cannabinoids from hemp. The increase in cannabidiolic acid concentration was 28% when compared to 100% ethanol, and 23% when compared to 100% acetonitrile. While it was determined that 50% ethanol is the most effective concentration for our application, the method has also been demonstrated to be effective with alternative solvents. Consequently, the proposed method is deemed effective and rapid for extracting acidic cannabinoids.

Ultrasonic-Assisted Extraction of Cannabidiolic Acid from Cannabis Biomass

Ultrasonic-assisted extraction (UAE) increases extraction efficiency of solvents and when applied to Cannabis spp. biomass it reduces the time required for extraction. This decreases the cost and potential cannabinoid loss due to degradation. Additionally, UAE is considered a green method due to low solvent use.

Industrial hemp (Cannabis spp.) has many compounds of interest with potential medical benefits. Of these compounds, cannabinoids have come to the center ...

Ultrafast Lignin Extraction from Unusual Mediterranean Lignocellulosic Residues

Pretreatment is still the most expensive step in lignocellulosic biorefinery processes. It must be made cost-effective by minimizing chemical requirements as well as power and heat consumption and by using environment-friendly solvents. Deep eutectic solvents (DESs) are key, green, and low-cost solvents in sustainable biorefineries. They are transparent mixtures characterized by low freezing points resulting from at least one hydrogen bond donor and one hydrogen bond acceptor. Although DESs are promising solvents, it is necessary to combine them with an economic heating technology, such as microwave irradiation, for competitive profitability. Microwave irradiation is a promising strategy to shorten the heating time and boost fractionation because it can rapidly attain the appropriate temperature. The aim of this study was to develop a one-step, rapid method for biomass fractionation and lignin extraction using a low-cost and biodegradable solvent. 
In this study, a microwave-assisted DES pretreatment was conducted for 60 s at 800 W, using three kinds of DESs. The DES mixtures were facilely prepared from choline chloride (ChCl) and three hydrogen-bond donors (HBDs): a monocarboxylic acid (lactic acid), a dicarboxylic acid (oxalic acid), and urea. This pretreatment was used for biomass fractionation and lignin recovery from marine residues (Posidonia leaves and aegagropile), agri-food byproducts (almond shells and olive pomace), forest residues (pinecones), and perennial lignocellulosic grasses (Stipa tenacissima). Further analyses were conducted to determine the yield, purity, and molecular weight distribution of the recovered lignin. In addition, the effect of DESs on the chemical functional groups in the extracted lignin was determined by Fourier-transform infrared (FTIR) spectroscopy. The results indicate that the ChCl-oxalic acid mixture affords the highest lignin purity and the lowest yield. The present study demonstrates that the DES-microwave process is an ultrafast, efficient, and cost-competitive technology for lignocellulosic biomass fractionation.

Deep eutectic solvent-based, microwave-assisted pretreatment is a green, fast, and efficient process for lignocellulosic fractionation and high-purity lignin recovery.

Pretreatment is still the most expensive step in lignocellulosic biorefinery processes. It must be made cost-effective by minimizing chemical requirements ...

Sonication Extraction of Lipid Biomarkers from Sediment

Source: Laboratory of Jeff Salacup&#160;- University of Massachusetts Amherst
The material comprising the living &#34;organic&#34; share of any ecosystem (leaves, fungi, bark, tissue; Figure 1) differs fundamentally from the material of the non-living &#34;inorganic&#34; share (rocks and their constituent minerals, oxygen, water, metals). Organic material contains carbon linked to a series of other carbon and hydrogen molecules (Figure 2), which distinguishes it from inorganic material. Carbon&#39;s wide valency range (-4 to +4) allows it to form up to four separate covalent bonds with neighboring atoms, usually C, H, O, N, S, and P. It can also share up to three covalent bonds with a single other atom, such as the triple bond in the often-poisonous cyanide, or nitrile, group. Over the past 4.6 billion years, this flexibility has led to an amazing array of chemical structures, which vary in size, complexity, polarity, shape, and function. The scientific field of organic geochemistry is concerned with the identification and characterization of the whole range of detectable organic compounds, called biomarkers, produced by life on this planet, as well as others, through geologic time.
<img alt="Figure 1" src="/files/ftp_upload/10055/10055fig1.jpg" /> 
Figure 1. Organic material, such as trees, leaves, and moss, are chemically and visually distinct from inorganic material, such as pavement.

Source: Laboratory of Jeff Salacup&#160;- University of Massachusetts Amherst
The material comprising the living &#34;organic&#34; share of any ecosystem ...

Ultrasonic-Assisted Preparation of Biodiesel Products from Vegetable Oils

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