Mitigation of methanol inactivation of lipases by reaction medium engineering with glycine betaine for enzymatic biodiesel synthesis

Fuel ◽  
2021 ◽  
pp. 122637
Author(s):  
Bhanu Prakash Sandaka ◽  
Jitendra Kumar ◽  
Jose Savio Melo
Keyword(s):  
Glycine Betaine ◽  
Reaction Medium ◽  
Biodiesel Synthesis

scholarly journals Magnetic Nano-Sized Solid Acid Catalyst Bearing Sulfonic Acid Groups for Biodiesel Synthesis

2018 ◽  
Vol 16 (1) ◽  
pp. 923-929 ◽  
Author(s):  
Sezer Erdem ◽  
Beyhan Erdem ◽  
Ramis Mustafa Öksüzoğlu
Keyword(s):  
Magnetic Nanoparticles ◽  
Solid Acid Catalyst ◽  
Reaction Medium ◽  
Chlorosulfonic Acid ◽  
Acid Catalyst ◽  
Magnetic Core ◽  
Biodiesel Production ◽  
Silica Layer ◽  
Magnetic Iron Oxide Nanoparticles ◽  
Biodiesel Synthesis

AbstractIn our approach for magnetic iron oxide nanoparticles surface modification, the fabrication of an inorganic shell, consisting of silica by the deposition of preformed colloids onto the nanoparticle surface and functionalization of these particles, was realized. The magnetic nanoparticles, non-coated and coated with silica layer by Stöber method, are functionalized with chlorosulfonic acid. The magnetic nanoparticles (MNPs), in size of 10-13 nm, could be used as acid catalyst in biodiesel production and show superparamagnetic character. The prepared nanoparticles were characterized by different methods including XRD, EDX, FT-IR and VSM. The catalytic activity of the coated and non-coated solid acids was examined in palmitic acid-methanol esterification as an industrial reaction for biodiesel synthesis. Although thin silica layer results in only a minor obstacle with respect to magnetism, it can accelerate the mass transportation due to its relatively porous structure and magnetic core may be more stable in the acidic reaction medium by means of covering process. Accordingly, coating strategy can be efficient way for allowing applications of MNPs in acid catalyzed esterification.

scholarly journals Oligocat: Oligoesters as Pseudo-Homogenous Catalysts for Biodiesel Synthesis

Polymers ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 210
Author(s):  
Vitor Vlnieska ◽  
Aline Silva Muniz ◽  
Angelo Roberto dos Santos Oliveira ◽  
Maria Aparecida Ferreira César-Oliveira ◽  
Danays Kunka
Keyword(s):  
Conversion Rate ◽  
First Generation ◽  
Second Generation ◽  
Reaction Medium ◽  
Acid Catalyst ◽  
Biodiesel Production ◽  
European Federation ◽  
Alkyl Esters ◽  
Production Chain ◽  
Biodiesel Synthesis

Biodiesel production from first-generation feedstock has shown a strong correlation with the increase in deforestation and the necessity of larger areas for land farming. Recent estimation from the European Federation for Transport and Environment evidenced that since the 2000s decade, an area equal to the Netherlands was deforested to supply global biodiesel demand, mainly originating from first-generation feedstock. Nevertheless, biodiesel is renewable, and it can be a greener source of energy than petroleum. A promising approach to make biodiesel independent from large areas of farming is to shift as much as possible the biodiesel production chain to second and third generations of feedstock. The second generation presents three main advantages, where it does not compete with the food industry, its commercial value is negligible, or none, and its usage as feedstock for biodiesel production reduces the overall waste disposal. In this manuscript, we present an oligomeric catalyst designed to be multi-functional for second-generation feedstock transesterification reactions, mainly focusing our efforts to optimize the conversion of tallow fat and sauteing oil to FAME and FAEE, applying our innovative catalyst. Named as Oligocat, our catalyst acts as a Brønsted-Lowry acid catalyst, providing protons to the reaction medium, and at the same time, with the course of the reaction, it sequesters glycerol molecules from the medium and changes its physical phase during the transesterification reaction. With this set of properties, Oligocat presents a pseudo-homogenous behavior, reducing the purification and separation steps of the biodiesel process production. Reaction conditions were optimized applying a 42 factorial planning. The output parameter evaluated was the conversion rate of triacylglycerol to mono alkyl esters, measured through gel permeation chromatography (GPC). After the optimization studies, a conversion yield of 96.7 (±1.9) wt% was achieved, which allows classifying the obtained mono alkyl esters as biodiesel by ASTM D6751 or EN 14214:2003. After applying the catalyst in three reaction cycles, Oligocat still presented a conversion rate above 96.5 wt% and as well an excellent recovery rate.

Basic Ion Exchange Resins as Heterogeneous Catalysts for Biodiesel Synthesis

2010 ◽  
Vol 132 ◽  
pp. 220-227 ◽  
Author(s):  
Marisa G. Falco ◽  
Carlos D. Córdoba ◽  
María R. Capeletti ◽  
Ulises Sedran
Keyword(s):  
Ion Exchange ◽  
Heterogeneous Catalysts ◽  
Methyl Esters ◽  
Reaction Medium ◽  
Ion Exchange Resins ◽  
Reaction Products ◽  
Macroporous Resin ◽  
Biodiesel Synthesis ◽  
Exchange Resins ◽  
The Impact

Basic and acidic ion exchange resins were used as catalysts for the synthesis of biodiesel from soybean oil and methanol. The impact of reaction parameters like molar methanol/oil relationship, catalyst mass and reaction temperature were studied. The catalysts did not show deactivation and the reaction medium remained neutral. The performance of the resins was compared against reference catalysts (NaOH; MgO). A strongly basic macroporous resin was the most active catalyst and it was possible to reach 100 % selectivity to methyl esters. A series reaction mechanism was consistent with the evolutions of the intermediate reaction products.

High-voltage cytochemistry for three-dimensional observation of nuclei and calculation of total numbers of nuclear pores in retinal Mueller glia

1990 ◽  
Vol 48 (3) ◽  
pp. 956-957
Author(s):  
H. Ishigooka ◽  
S. Ueno ◽  
L.M. Hjelmeland ◽  
M.B. Landers ◽  
K. Ogawa
Keyword(s):  
Nuclear Envelope ◽  
High Voltage ◽  
Three Dimensional ◽  
Reaction Medium ◽  
Nuclear Pores ◽  
High Voltage Electron Microscopy ◽  
Voltage Electron ◽  
High Voltage Electron ◽  
G6pase Activity ◽  
Mueller Glia

Introduction: We have demonstrated that Glucose-6-phosphatase (G6Pase) activity is localized to the endoplasmic reticulum and nuclear envelope of Mueller glia in the normal and pathological guinea pig retina. Using a combination of this cytochemical technique and high voltage electron microscopy, the distribution of nuclear pores could be clearly observed on the nuclear envelope of Mueller glia because of their anatomical lack of reaction products. This technique was developed to study the three-dimensional structure of nuclei and to calculate total numbers of nuclear pores utilizing a computer graphic analysis system in the normal and pathological retina.Materials and methods: Normal and photocoagulated retina of pigmented adult guinea pigs were perfused with a cold mixture of 0.25% glutaraldehyde and 2% paraformaldehyde in 0.1M cacodylate buffer, and the enucleated globes were hemisected and immersed in the same fixative for 30 min. After sectioning and incubation in the reaction medium for the detection of G6Pase activity by the method of Wachstein-Meisel, the sections were postfixed, dehydrated and embedded in Spurr’s epoxy resin. Serial thick sections (1.0um) were prepared for the observation by a Hitachi high voltage electron microscope (H 1250-M) with an accelerating voltage of 1000 Kv. and pictures were analyzed and three-dimensionally reconstructed by TRI (RATOC Co., Ltd.).

Reaction of Acetaldehyde with Human Platelets

1992 ◽  
Vol 67 (01) ◽  
pp. 126-130 ◽  
Author(s):  
Olivier Spertini ◽  
Jacques Hauert ◽  
Fedor Bachmann
Keyword(s):  
Platelet Aggregation ◽  
Inhibitory Action ◽  
Ex Vivo ◽  
Platelet Rich Plasma ◽  
Shape Change ◽  
Reaction Medium ◽  
Human Platelets ◽  
Membrane Glycoproteins ◽  
Neutral Ph

SummaryPlatelet function defects observed in chronic alcoholics are not wholly explained by the inhibitory action of ethanol on platelet aggregation; they are not completely reproduced either in vivo by short-term ethanol perfusion into volunteers or in vitro by the addition of ethanol to platelet-rich plasma. As acetaldehyde (AcH) binds to many proteins and impairs cellular activities, we investigated the effect of this early degradation product of ethanol on platelets. AcH formed adducts with human platelets at neutral pH at 37° C which were stable to extensive washing, trichloracetic acid hydrolysis and heating at 100° C, and were not reduced by sodium borohydride. The amount of platelet adducts formed was a function of the incubation time and of the concentration of AcH in the reaction medium. At low AcH concentrations (<0.2 mM), platelet bound AcH was directly proportional to the concentration of AcH in the reaction medium. At higher concentrations (≥0.2 mM), AcH uptake by platelets tended to reach a plateau. The amount of adducts was also proportional to the number of exposures of platelets to pulses of 20 pM AcH.AcH adducts formation severely impaired platelet aggregation and shape change induced by ADP, collagen and thrombin. A positive correlation was established between platelet-bound AcH and inhibition of aggregation.SDS-PAGE analysis of AcH adducts at neutral pH demonstrated the binding of [14C]acetaldehyde to many platelet proteins. AcH adduct formation with membrane glycoproteins, cytoskeleton and enzymes might interfere with several steps of platelet activation and impair platelet aggregation.This in vitro study shows that AcH has a major inhibitory action on platelet aggregation and may account for the prolonged ex vivo inhibition of aggregation observed in chronic alcoholics even in the absence of alcoholemia.

Chemical Transformation of Fe, Air & Water to Ammonia: Variation of Reaction Rate with Temperature, Pressure, Alkalinity and Iron

2018 ◽  
Author(s):  
Ping Peng ◽  
Fang-Fang Li ◽  
Xinye Liu ◽  
Jiawen Ren ◽  
jessica stuart ◽  
...  
Keyword(s):  
Particle Size ◽  
Reaction Rate ◽  
Electrolyte Concentration ◽  
Iron Concentration ◽  
Reaction Medium ◽  
Iron Particle ◽  
Intermediate Step ◽  
Ammonia Production ◽  
Pure Nitrogen ◽  
Alkaline Reaction

The rate of ammonia production by the <u>chemical </u>oxidation of iron, N<sub>2</sub>(from air or as pure nitrogen) and water is studied as a function of (1) iron particle size, (2) iron concentration, (3) temperature, (4) pressureand (5) concentration of the alkaline reaction medium. The reaction meduium consists of an aqueous solution of equal molal concentrations of NaOH and KOH (Na<sub>0.5</sub>K<sub>0.5</sub>OH). We had previously reported on the <u>chemical </u>reaction of iron and nitrogen in alkaline medium to ammonia as an intermediate step in the <u>electrochemical </u>synthesis of ammonia by a nano-sized iron oxide electrocatlyst. Here, the intermediate <u>chemical </u>reaction step is exclusively explored. The ammonia production rate increases with temperature (from 20 to 250°C), pressure (from 1 atm to 15 atm of air or N<sub>2</sub>), and exhibits a maximum rate at an electrolyte concentration of 8 molal Na<sub>0,5</sub>K<sub>0,5</sub>OH in a sealed N<sub>2</sub>reactor. 1-3 µm particle size Fe drive the highest observed ammonia production reaction rate. The Fe mass normalized rate of ammonia production increases with decreasing added mass of the Fe reactant reaching a maximum observed rate of 2.2x10<sup>-4</sup>mole of NH<sub>3</sub>h<sup>-1</sup>g<sup>-1</sup>for the reaction of 0.1 g of 1-3 µm Fe in 200°C 8 molal Na<sub>0.5</sub>K<sub>0.5</sub>OH at 15 atm. Under these conditions 5.1 wt% of the iron reacts to form NH<sub>3</sub>via the reaction N<sub>2</sub>+ 2Fe + 3H<sub>2</sub>O ®2NH<sub>3</sub>+ Fe<sub>2</sub>O<sub>3</sub>.

An Overview of Metal-organic Frameworks-based Acid/Base Catalysts for Biofuel Synthesis

2020 ◽  
Vol 24 (16) ◽  
pp. 1876-1891
Author(s):  
Qiuyun Zhang ◽  
Yutao Zhang ◽  
Jingsong Cheng ◽  
Hu Li ◽  
Peihua Ma
Keyword(s):  
Alternative Fuels ◽  
Heterogeneous Catalysts ◽  
Supported Catalysts ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Flexible Structures ◽  
Biodiesel Production ◽  
Biodiesel Synthesis ◽  
Metal Organic ◽  
Organic Framework

Biofuel synthesis is of great significance for producing alternative fuels. Among the developed catalytic materials, the metal-organic framework-based hybrids used as acidic, basic, or supported catalysts play major roles in the biodiesel production. This paper presents a timely and comprehensive review of recent developments on the design and preparation of metal-organic frameworks-based catalysts used for biodiesel synthesis from various oil feedstocks, including MILs-based catalysts, ZIFs-based catalysts, UiO-based catalysts, Cu-BTC-based catalysts, and MOFs-derived porous catalysts. Due to their unique and flexible structures, excellent thermal and hydrothermal stability, and tunable host-guest interactions, as compared with other heterogeneous catalysts, metal-organic framework-based catalysts have good opportunities for application in the production of biodiesel at industrial scale.

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