scholarly journals Continuous Catalyst-Free Esterification of Oleic Acid in Compressed Ethanol

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Ana Carolina de Araujo Abdala ◽  
Vitor Augusto dos Santos Garcia ◽  
Caroline Portilho Trentini ◽  
Lúcio Cardozo Filho ◽  
Edson Antonio da Silva ◽  
...  
Keyword(s):  
Oleic Acid ◽  
Residence Time ◽  
Tubular Reactor ◽  
Reaction Medium ◽  
Ethyl Esters ◽  
Molar Ratio ◽  
Molar Ratios ◽  
Catalyst Free ◽  
Free Process ◽  
Positive Effect

The esterification of oleic acid in a continuous catalyst-free process using compressed ethanol was investigated in the present study. Experiments were performed in a tubular reactor and variables investigated were temperature, pressure, and oleic acid to ethanol molar ratio for different residence time. Results demonstrated that temperature, in the range of 473 K to 573 K, and pressure had a positive effect on fatty acid ethyl esters (FAEE) production. In the experimental range investigated, high conversions can be obtained at low ethanol concentrations in the reaction medium and it was observed that oleic acid to ethanol molar ratios greater than 1 : 6 show no significant increase in conversion. Nonnegligible reaction conversions (>90%) were achieved at 573 K, 20 MPa, oleic acid to ethanol molar ratio of 1 : 6, and 20 minutes of residence time.

scholarly journals Lipozyme 435-Mediated Synthesis of Xylose Oleate in Methyl Ethyl Ketone

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3317
Author(s):  
Maria Carolina Pereira Gonçalves ◽  
Jéssica Cristina Amaral ◽  
Roberto Fernandez-Lafuente ◽  
Ruy de Sousa Junior ◽  
Paulo Waldir Tardioli
Keyword(s):  
Oleic Acid ◽  
Methyl Ethyl Ketone ◽  
Molar Ratio ◽  
Methyl Ethyl ◽  
Sugar Ester ◽  
Molar Ratios ◽  
Emulsion Capacity ◽  
Ping Pong ◽  
Commercial Sugar ◽  
Repeated Use

In this paper, we have performed the Lipozyme 435-catalyzed synthesis of xylose oleate in methyl ethyl ketone (MEK) from xylose and oleic acid. The effects of substrates’ molar ratios, reaction temperature, reaction time on esterification rates, and Lipozyme 435 reuse were studied. Results showed that an excess of oleic acid (xylose: oleic acid molar ratio of 1:5) significantly favored the reaction, yielding 98% of xylose conversion and 31% oleic acid conversion after 24 h-reaction (mainly to xylose mono- and dioleate, as confirmed by mass spectrometry). The highest Lipozyme 435 activities occurred between 55 and 70 °C. The predicted Ping Pong Bi Bi kinetic model fitted very well to the experimental data and there was no evidence of inhibitions in the range assessed. The reaction product was purified and presented an emulsion capacity close to that of a commercial sugar ester detergent. Finally, the repeated use of Lipozyme 435 showed a reduction in the reaction yields (by 48 and 19% in the xylose and oleic acid conversions, respectively), after ten 12 h-cycles.

scholarly journals Influence of Particle Size, Reactor Temperature and Gas Phase Reactions on Fast Pyrolysis of Beech Wood

2010 ◽  
Vol 8 (1) ◽  
Author(s):  
Li Chen ◽  
Capucine Dupont ◽  
Sylvain Salvador ◽  
Guillaume Boissonnet ◽  
Daniel Schweich
Keyword(s):  
Particle Size ◽  
Gas Phase ◽  
Residence Time ◽  
Beech Wood ◽  
Tubular Reactor ◽  
Gaseous Product ◽  
Drop Tube ◽  
Gas Phase Reactions ◽  
Molar Ratios ◽  
Reactor Temperature

In the present work, a drop tube reactor (DTR) and a horizontal tubular reactor (HTR) were used to study the pyrolysis behaviour of beech wood particles of different sizes under the conditions encountered in industrial fluidized bed gasifiers, namely high external heat flux (105 – 106 W.m-2) and high temperature (800 – 1000°C). The influence of the reactor temperature (800 and 950°C), of particle size (from 350 µm to 6 mm), and of gas residence time (from 1 to 10 s) were examined. Under the explored conditions, when pyrolysis is finished, more than 80 wt.% of virgin wood is converted into gas and less than 13 wt.% remains in solid. In the gas phase, CO is the main gaseous product (50 wt.% of virgin wood), followed by H2 (molar ratios of H2/CO are between 0.35 to 0.55), H2O, CO2 and CH4. Species C2H2, C2H4, C2H6 and C6H6 are present in much lower amounts. The increase of temperature increases the rate of solid devolatilization and favours the cracking reactions of hydrocarbons. The increase of particle size increases the required time for completing pyrolysis. Meanwhile, the results obtained at 950°C show that the final products distribution at the end of pyrolysis is almost the same for the particles between 350 and 800 µm. The increase of the particle size from 800 µm to 6 mm seems to have some influence on the final products distribution. The gas phase reactions mainly change the yields of light hydrocarbons and H2: the increase of gas residence time favours the cracking reactions of hydrocarbons and thus leads to a higher H2 yield.

scholarly journals DOPE–oleic acid–Ca2+ as DNA condensing agent

2018 ◽  
Vol 65 (1) ◽  
pp. 1-9
Author(s):  
D. Galliková ◽  
G. Liskayová ◽  
A. Búcsi ◽  
L. Hubčík ◽  
J.C. Martínez ◽  
...  
Keyword(s):  
Oleic Acid ◽  
Binding Capacity ◽  
Hexagonal Phase ◽  
Dna Delivery ◽  
Lattice Parameter ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Time Intervals ◽  
Molar Ratios ◽  
Dominant Structure

Abstract Phospholipid-based non-viral carriers composed of neutral phospholipid dioleoylphosphatidylethanolamine (DOPE) and the binary mixture DOPE–oleic acid (OA) are examined as potential DNA delivery vectors. The process of DNA condensation in the presence of Ca2+ ions has been monitored through changes in emmision intensity of fluorescent probe ethidium bromide. The decline in fluorescence intensity with increasing Ca2+ concentration at two different time intervals was correlated with the binding capacity of complexes and possible release of DNA from the complex. The microstructure of DOPE–OA mixtures at different OA/DOPE molar ratios and that of DOPE–OA–DNA–Ca2+ complexes were determined using synchrotron small angle X-ray diffraction (SAXD). We identified inverted hexagonal phase HII as the dominant structure. OA affects the lattice parameter of HII formed by DOPE. With the increasing OA/DOPE molar ratio, the lattice parameter decreases, which results in significantly lower fraction of DNA bound to the OA-enriched complexes.

Hydrothermal synthesis of BiVO4/Bi2MoO6 composites with enhanced photocatalytic activity

2017 ◽  
Vol 31 (16-19) ◽  
pp. 1744059 ◽  
Author(s):  
Chaoqi Xu ◽  
Hongzhi Qian ◽  
Haibo Yong ◽  
Xiaogu Huang ◽  
Wei Wang ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Molar Ratio ◽  
Moderate Amount ◽  
Molar Ratios ◽  
Photocatalytic Activities ◽  
Efficient Charge ◽  
One Step ◽  
Carrier Separation ◽  
The One ◽  
Positive Effect

BiVO4/Bi2MoO6 composites have been fabricated via the one-step hydrothermal method. The properties of composites were tailored by altering the V/Mo molar ratios. Photocatalytic activities were evaluated by measuring degradation of RhB under visible-light irradiation. BiVO4/Bi2MoO6 composites with V/Mo molar ratio of 8:1 possessing the optimal photocatalytic performance. The enhanced photocatalytic activity was attributed to the efficient charge carrier separation of composite heterostructures. In addition, the study of adsorption and photocatalytic activity suggested that a moderate amount of adsorption has a positive effect on photocatalytic reaction.

scholarly journals REAKSI KATALITIS ESTERIFIKASI ASAM OLEAT DAN METANOL MENJADI BIODIESEL DENGAN METODE DISTILASI REAKTIF

REAKTOR ◽  
2008 ◽  
Vol 12 (2) ◽  
pp. 78 ◽  
Author(s):  
Kusmiyati Kusmiyati
Keyword(s):  
Oleic Acid ◽  
Reactive Distillation ◽  
Reaction Times ◽  
Biodiesel Production ◽  
Molar Ratio ◽  
Molar Ratios ◽  
Animal Fats ◽  
Alternative Diesel Fuel ◽  
Result Show ◽  
American Standard

Biodiesel is an alternative diesel fuel that is produced from vegetable oils and animal fats. Generally, it is formed by trans etherification reaction of triglycerides in the vegetable oil or animal fat with an alcohol. In this work, etherification reaction was carried out using oleic acid, methanol and sulphuric acid as a catalyst by reactive distillation method. In order to determine the best conditions for biodiesel production by reactive distillation, the experiments were carried out at different temperature (1000C, 1200C, 1500C and 1800C) using methanol/oleic acid molar ratios (1:1, 5:1, 6:1, 7:1, 8:1), catalyst/ oleic acid molar ratios (0.5%wt, 1%wt, 1.5%wt and 2%wt) and reaction times (15, 30, 45, 60, 75 and 90 minutes). Result show that at temperature 1800C, methanol/oleic acid molar ratio of 8:1, amount of catalyst 1% for 90 minute reaction time gives the highest conversion of oleic acid above 0.9581. Biodiesel product from oleic acid was analyzed by ASTM (American Standard for Testing Material). The results show that the biodiesel produced has the quality required to be a diesel substitute. Biodiesel merupakan salah satu bahan bakar alternatif pengganti bahan bakar fosil yang diproduksi dari bahan baku minyak nabati dan lemak hewan. Secara umum biodiesel diproduksi melalui reaksi transesterifikasi minyak nabati atau lemak hewan dan alkohol. Pada penelitian ini proses esterifikasi pada pembuatan biodiesel menggunakan bahan baku asam oleat murni (99%), metanol dan katalis asam sulfat dengan metode distilasi reaktif. Distilasi reaktif merupakan penggabungan antara proses reaksi dan proses pemisahan dalam satu unit proses sehingga memungkinkan diperoleh biodiesel dengan kemurnian yang tinggi. Variabel yang dipelajari pada penelitian ini adalah temperatur (1000C, 1200C, 1500C, 1800C), jumlah katalis H2SO4 (0,5% berat, 1% berat, 1,5% berat, 2% berat), rasio metanol : asam oleat dinyatakan 1:1, 5:1, 6:1, 7:1, 8:1 (dalam % berat) terhadap konversi asam oleat serta. Berdasarkan hasil penelitian, konversi maksimum yang dapat dicapai sebesar 0,9581 pada kondisi reaksi berat katalis H2SO4 1% berat, rasio metanol:asam oleat 8:1 dan suhu reaksi 1800C. Berdasarkan hasil analisa ASTM, biodiesel yang diperoleh memenuhi standar bahan bakar cair dan dapat digunakan sebagai bahan bakar pengganti petroleum diesel.

scholarly journals Development and Optimization of Lipase-Catalyzed Synthesis of Phospholipids Containing 3,4-Dimethoxycinnamic Acid by Response Surface Methodology

Catalysts ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 588
Author(s):  
Magdalena Rychlicka ◽  
Natalia Niezgoda ◽  
Anna Gliszczyńska
Keyword(s):  
Response Surface Methodology ◽  
Food Additives ◽  
Reaction Medium ◽  
Egg Yolk ◽  
Molar Ratio ◽  
Molar Ratios ◽  
Egg Yolk Phosphatidylcholine ◽  
Potential Applications ◽  
Substrate Molar Ratio ◽  
Enzyme Load

The interesterification reaction of egg-yolk phosphatidylcholine (PC) with ethyl ester of 3,4-dimethoxycinnamic acid (E3,4DMCA) catalyzed by Novozym 435 in hexane as a reaction medium was shown to be an effective method for the synthesis of corresponding structured O-methylated phenophospholipids. The effects of substrate molar ratios, time of the reaction and enzyme load on the process of incorporation of 3,4DMCA into PC were evaluated by using the experimental factorial design of three factors and three levels. The results showed that a substrate molar ratio is a crucial variable for the maximization of the synthesis of 3,4-dimethoxycinnamoylated phospholipids. Under optimized parameters of 1/10 substrate molar ratio PC/E3,4DMCA, enzyme load 30% (w/w), hexane as a medium and incubation time of 3 days, the incorporation of aromatic acid into phospholipid fraction reached 21 mol%. The modified phosphatidylcholine (3,4DMCA-PC) and modified lysophosphatidylcholine (3,4DMCA-LPC) were obtained in isolated yields of 3.5% and 27.5% (w/w), respectively. The developed method of phosphatidylcholine interesterification is the first described in the literature dealing with 3,4DMCA and allows us to obtain new O-methylated phenophospholipids with potential applications as food additives or nutraceuticals with pro-health activity.

Metathesis Polymerization of Phenylacetylene by Tungsten Aryloxo Complexes

1995 ◽  
Vol 60 (3) ◽  
pp. 489-497 ◽  
Author(s):  
Hynek Balcar ◽  
Jan Sedláček ◽  
Marta Pacovská ◽  
Vratislav Blechta
Keyword(s):  
Molecular Weight ◽  
Catalytic Activity ◽  
Induction Period ◽  
Average Molecular Weight ◽  
Molar Fraction ◽  
Molar Ratio ◽  
Weight Average Molecular Weight ◽  
Polymer Yield ◽  
Positive Effect ◽  
Ligand Addition

Catalytic activity of the tungsten aryloxo complexes WCl5(OAr) and WOCl3(OAr), where Ar = 4-t-C4H9C6H4, 2,6-(t-C4H9)2C6H3, 2,6-Cl2C6H3, 2,4,6-Cl3C6H2, and 2,4,6-Br3C6H2 in polymerization of phenylacetylene (20 °C, monomer to catalyst molar ratio = 1 000) was studied. The activity of WCl5(OAr) as unicomponent catalysts increases with increasing electron withdrawing character of the -OAr ligand. Addition of two equivalents of organotin cocatalysts (Me4Sn, Bu4Sn, Ph4Sn, Bu3SnH) to WCl5(O-C6H2Cl3-2,4 ,6) has only slight positive effect (slightly higher polymer yield and/or molecular weight of poly(phenylacetylene)s was achieved). However, in the case of WOCl3(O-C6H3Cl2-2, 6) catalyst, it enhances the activity considerably by eliminating the induction period. Poly(phenylacetylene)s prepared with the catalysts studied have weight-average molecular weight ranging from 100 000 to 200 000. They are trans-prevailing and have relatively low molar fraction of monomer units comprised in cyclohexadiene sequences (about 6%).

scholarly journals Photocatalytic Reduction of CO2 to Methanol Using a Copper-Zirconia Imidazolate Framework

Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 346
Author(s):  
Sonam Goyal ◽  
Maizatul Shima Shaharun ◽  
Ganaga Suriya Jayabal ◽  
Chong Fai Kait ◽  
Bawadi Abdullah ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Catalyst Support ◽  
Oxidation Potential ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Molar Ratios ◽  
Optimum Parameters ◽  
Reduction Of Co2 ◽  
Enhanced Yield

A set of novel photocatalysts, i.e., copper-zirconia imidazolate (CuZrIm) frameworks, were synthesized using different zirconia molar ratios (i.e., 0.5, 1, and 1.5 mmol). The photoreduction process of CO2 to methanol in a continuous-flow stirred photoreactor at pressure and temperature of 1 atm and 25 °C, respectively, was studied. The physicochemical properties of the synthesized catalysts were studied using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL) spectroscopy. The highest methanol activity of 818.59 µmol/L.g was recorded when the CuZrIm1 catalyst with Cu/Zr/Im/NH4OH molar ratio of 2:1:4:2 (mmol/mmol/mmol/M) was employed. The enhanced yield is attributed to the presence of Cu2+ oxidation state and the uniformly dispersed active metals. The response surface methodology (RSM) was used to optimize the reaction parameters. The predicted results agreed well with the experimental ones with the correlation coefficient (R2) of 0.99. The optimization results showed that the highest methanol activity of 1054 µmol/L.g was recorded when the optimum parameters were employed, i.e., stirring rate (540 rpm), intensity of light (275 W/m2) and photocatalyst loading (1.3 g/L). The redox potential value for the CuZrIm1 shows that the reduction potential is −1.70 V and the oxidation potential is +1.28 V for the photoreduction of CO2 to methanol. The current work has established the potential utilization of the imidazolate framework as catalyst support for the photoreduction of CO2 to methanol.

scholarly journals Synthesis and Characterization of Partially Renewable Oleic Acid-Based Ionomers for Proton Exchange Membranes

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 130
Author(s):  
Carlos Corona-García ◽  
Alejandro Onchi ◽  
Arlette A. Santiago ◽  
Araceli Martínez ◽  
Daniella Esperanza Pacheco-Catalán ◽  
...  
Keyword(s):  
Oleic Acid ◽  
Proton Conductivity ◽  
Electrochemical Impedance ◽  
Proton Exchange Membranes ◽  
Proton Exchange ◽  
Molar Ratio ◽  
Aromatic Diamines ◽  
Chemical Structures ◽  
Long Chain

The future availability of synthetic polymers is compromised due to the continuous depletion of fossil reserves; thus, the quest for sustainable and eco-friendly specialty polymers is of the utmost importance to ensure our lifestyle. In this regard, this study reports on the use of oleic acid as a renewable source to develop new ionomers intended for proton exchange membranes. Firstly, the cross-metathesis of oleic acid was conducted to yield a renewable and unsaturated long-chain aliphatic dicarboxylic acid, which was further subjected to polycondensation reactions with two aromatic diamines, 4,4′-(hexafluoroisopropylidene)bis(p-phenyleneoxy)dianiline and 4,4′-diamino-2,2′-stilbenedisulfonic acid, as comonomers for the synthesis of a series of partially renewable aromatic-aliphatic polyamides with an increasing degree of sulfonation (DS). The polymer chemical structures were confirmed by Fourier transform infrared (FTIR) and nuclear magnetic resonance (1H, 13C, and 19F NMR) spectroscopy, which revealed that the DS was effectively tailored by adjusting the feed molar ratio of the diamines. Next, we performed a study involving the ion exchange capacity, the water uptake, and the proton conductivity in membranes prepared from these partially renewable long-chain polyamides, along with a thorough characterization of the thermomechanical and physical properties. The highest value of the proton conductivity determined by electrochemical impedance spectroscopy (EIS) was found to be 1.55 mS cm−1 at 30 °C after activation of the polymer membrane.

scholarly journals The relationship of oleic acid/albumin molar ratio and clinical outcomes in leptospirosis

Heliyon ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. e06420
Author(s):  
Caroline Azevedo Martins ◽  
Maria Conceição B dos Santos ◽  
Cassiano Felippe Gonçalves-de-Albuquerque ◽  
Hugo Caire Castro-Faria-Neto ◽  
Mauro Velho Castro-Faria ◽  
...  
Keyword(s):  
Oleic Acid ◽  
Clinical Outcomes ◽  
Molar Ratio ◽  
Relationship Of ◽  
The Relationship
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