scholarly journals Chitosan with Sulfonic Groups: A Catalyst for the Esterification of Caprylic Acid with Methanol

Polymers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3924
Author(s):  
José Castanheiro

Esterification of caprylic acid with methanol was performed over chitosan with sulfonic acid groups, as a catalyst, at 60 °C. The sulfonic acid groups were introduced into chitosan (CH) by using chlorosulfonic acid. Catalysts were characterized by scanning electron microscopy (SEM), elemental analysis, thermogravimetric analysis (TGA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and acid–base titration. Catalytic activity increased with the amount of sulfonic acid groups present on chitosan. The 4–CH–SO3H catalyst (chitosan with sulfonic acid groups—sample 4 prepared) showed the highest activity of all materials. The esterification of caprylic acid with methanol was optimized using a 4–CH–SO3H catalyst. Under optimized reaction conditions, it was found that, at 60 °C, with 0.2 g of catalyst loading and with a molar ratio methanol to caprylic acid equal 1:95, a caprylic acid conversion of about 83%, after 4 h could be obtained. Catalytic stability of the 4–CH–SO3H material was evaluated through consecutive batch runs. After the second batch, the catalytic activity stabilized.

2011 ◽  
Vol 89 (5) ◽  
pp. 544-548 ◽  
Author(s):  
Zhen-Zhen Yang ◽  
Xiao-Yong Dou ◽  
Fang Wu ◽  
Liang-Nian He

NaZSM-5 zeolite was found to be an efficient heterogeneous catalyst for the synthesis of dimethyl carbonate (DMC), which can serve as a building block, an additive to fuel oil, and an electrolyte in batteries, via the transesterification of ethylene carbonate (EC) with methanol. Notably, 77% DMC yield and 97% selectivity were achieved under mild reaction conditions. Furthermore, the effects of various reaction parameters such as catalyst loading, reaction time, and methanol/EC molar ratio on the catalytic performance were investigated in detail. This protocol was found to be applicable to a variety of alcohols, producing the corresponding dialkyl carbonates with moderate yields and selectivities. Moreover, the catalyst can be recovered by simple filtration with retention of catalytic activity; a stable crystal configuration and a slight alteration of its superficial structure were observed by X-ray diffraction and BET measurements.


2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Leandro Marques Correia ◽  
Juan Antonio Cecilia ◽  
Enrique Rodríguez-Castellón ◽  
Célio Loureiro Cavalcante ◽  
Rodrigo Silveira Vieira

The CaO solid derived from natural quail eggshell was calcined and employed as catalyst to produce biodiesel via transesterification of sunflower oil. The natural quail eggshell was calcined at 900°C for 3 h, in order to modify the calcium carbonate present in its structure in CaO, the activity phase of the catalyst. Both precursor and catalyst were characterized using Hammett indicators method, X-ray fluorescence (XRF), X-ray diffraction (XRD), thermogravimetric analysis (TG/DTG), CO2temperature-programmed desorption (CO2-TPD), X-ray photoelectronic spectroscopy (XPS), Fourier infrared spectroscopy (FTIR), scanning electron microscopy (SEM), N2adsorption-desorption at −196°C, and distribution particle size. The maximum biodiesel production was of 99.00 ± 0.02 wt.% obtained in the following transesterification reaction conditions:XMR(sunflower oil/methanol molar ratio of 1 : 10.5 mol : mol),XCAT(catalyst loading of 2 wt.%),XTIME(reaction time of 2 h), stirring rate of 1000 rpm, and temperature of 60°C.


2015 ◽  
Vol 13 (3) ◽  
pp. 389-393 ◽  
Author(s):  
Emine Sert

Abstract Within the framework of green chemistry, catalysts should be met different criteria such as biodegradability, recyclability, flammability, non-toxicity and low price. Acidic deep eutectic solvent (DES) have been synthesized for this purpose, by mixing para-toluene sulfonic acid and choline chloride. The catalytic activity of DES was studied in the esterification of acrylic acid with n-butanol. The usage of DES as catalyst is simple, safe and cheap. The effects of temperature, catalyst loading, n-butanol/acrylic acid molar ratio on the conversion of acrylic acid were performed. The batch reactor experiments were carried out at temperatures of 338, 348, 358 and 368 K, molar ratio of butanol to acrylic acid of 1, 2,3 and catalyst loading of 10, 15, 20 and 90 g/L. 90.2% of acrylic acid conversion was achieved at a temperature of 358 K and catalyst loading of 20 g/L. Reusability of DES was investigated. Reusability and catalytic activity makes DES efficient as catalyst.


2018 ◽  
Vol 1 (T5) ◽  
pp. 116-125
Author(s):  
Hai Truong Nguyen ◽  
Phuong Hoang Tran

Metal-organic framework MIL-53(Al) was synthesized by a solvothermal method using aluminium nitrate as the aluminium source and 1,4- benzenedicarboxylic acid (H2BDC) as the organic ligand. The structure of MIL-53(Al) was characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The catalytic activity and recyclability of MIL-53(Al) catalyst were evaluated based on the Paal-Knorr reaction between aniline and acetonylacetone. The reaction conditions were optimized and the results showed that the MIL-53(Al) catalyst exhibited good catalytic activity and recyclability based on the PaalKnorr reaction. With the molar ratio of MIL-53(Al) catalyst of 10 mol %, the molar ratio of aniline and acetonylacetone of 1:1.2, and without solvents, the conversion of aniline could reach 100 % and the selectivity of 2,5-dimethyl-1-phenyl-1H-pyrrole has high yield (95-100 %) after 2 hours by ultrasound activation. The MIL-53(Al) catalyst can be reused five times without significant degradation in the catalytic activity.


Author(s):  
Marwan Marwan ◽  
Eti Indarti ◽  
Darmadi Darmadi ◽  
Wahyu Rinaldi ◽  
Dzikri Hamzah ◽  
...  

Triacetin, an alternative biodiesel additive, was prepared by esterification of glycerol with acetic acid in the presence of chemically activated natural zeolite. The esterification was carried out in a small reaction flask under microwave irradiation. The catalyst was characterized for its morphology by SEM and its chemical composition by X-ray Diffraction (XRD). The Scanning Electron Microscopy (SEM) micrograph indicates improved surface area of the zeolite, while the XRD analysis shows an increase in Si/Al ratio from natural zeolite to 6.042 and its crystallinity value of 12.23%. The Fourier Transform Infra Red (FTIR) analysis obtained showed that microwave-heated samples have an esters group spectrum of triacetin at 1702 cm-1. The conversion value of glycerol was more than 95% at molar ratio of the reactants 1:9 and catalyst loading of 3%. The selectivities for monoacetin, diacetin and triacetin were 80.1%, 15.4%, and 4.5% at 60 minutes, and 43.0%, 48.6%, and 8.3% at 90 minutes. It shows that the conversion took place in consecutive steps and the use of microwave allows the reaction proceeding at milder condition. Copyright © 2019 BCREC Group. All rights reserved 


2021 ◽  
Vol 47 (2) ◽  
pp. 144-154
Author(s):  
G. G. Skvortsov ◽  
A. V. Cherkasov ◽  
D. L. Vorozhtsov ◽  
E. S. Shchegravina ◽  
A. A. Trifonov

Abstract The reaction of lithium β-diketiminate [{2,6-Me2C6H3N=CMe}2CH]Li with benzophenone in toluene at 25°C affords the coordination complex [{2,6-Me2C6H3N=CMe}2CH]Li(Ph2C=O) (I). New keto-β-diketimine {2,6-Me2C6H3N=C(Me)}2CHC(tert-Bu)=O (II) is synthesized by the reaction of tert-Bu(C=O)Cl with [{2,6-Me2C6H3N=CMe}2CH]Li. The metallation of keto-β-diketimine II with n-butyllithium in THF at 0°C gives lithium keto-β-diketiminate {[{2,6-Me2C6H3N=C(Me)}2CС(tert-Bu)=O]Li(THF)}n (III). The exchange reaction of YCl3 with compound III (molar ratio 1 : 2, THF) affords the yttrium bis(keto-diketiminate) complex [{2,6-Me2C6H3N=C(Me)}2CС(tert-Bu)=O]2Y(μ2-Cl)2L-(THF)2 (IV). The molecular structures of complexes I, III, and IV are determined by X-ray diffraction analysis (CIF files CCDC nos. 2001131 (I), 2001132 (III), and 2001133 (IV)). Complex IV in the crystalline state exists as an ate complex with one LiCl molecule. Complexes I, III, and IV are catalysts of ring-opening polymerization of ε-caprolactone in toluene at 25°С.


2020 ◽  
Author(s):  
Rajagopal Ramkumar ◽  
Shradha Sapru ◽  
Panthalattu Parambil Archana

<div>An extract of <i>Aloe Vera</i> acts as a powerful reducing agent for the synthesis of ultrasmall copper nanoparticles (CuNPs) in water medium. The prepared copper nanoparticles are characterized by XRD, HRTEM and UV-Vis analysis. The diameter of the prepared nanoparticle is less than 5 nm. The catalytic activity of CuNPs has been successfully evaluated for the three-component reaction to synthesize 1,2,3-triazoles and chalcone tethered 1,2,3-triazoles with low catalyst loading and under mild reaction conditions. These triazoles are further utilized for the synthesis of dihydropyrazines.</div>


Catalysts ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 710 ◽  
Author(s):  
Xiaochuan Zou ◽  
Xuyuan Nie ◽  
Zhiwen Tan ◽  
Kaiyun Shi ◽  
Cun Wang ◽  
...  

In this paper, a solid acid catalyst (ZPS–PVPA–SO3H) was prepared by anchoring thiol group on zirconium poly(styrene-phenylvinyl-phosphonate)-phosphate (ZPS–PVPA), followed by oxidation of thiol groups to obtain sulfonic acid groups. The solid acid catalyst was characterized by XPS, X-ray, EDS, SEM, and TG-DSC. The successful preparation of sulfonic acid-functionalized ZPS–PVPA was confirmed. Subsequently, the catalytic performance of ZPS–PVPA–SO3H was investigated in the epoxidation of soybean oil. The results demonstrated that ZPS–PVPA–SO3H can effectively catalyze epoxidation of soybean oil with TBHP as an oxidant. Moreover, there was no significant decrease in catalytic activity after 5 repeated uses of the ZPS–PVPA–SO3H. Interestingly, the ZPS–PVPA–SO3H was kept in 2 mol/L of HCl overnight after the end of the seventh reaction, and the catalytic activity was gradually restored during the eighth to tenth cycles.


2021 ◽  
Vol 18 ◽  
Author(s):  
Shefa Mirani Nezhad ◽  
Seied Ali Pourmousavi ◽  
Ehsan Nazarzadeh Zare

: A highly efficient heterogeneous nanocatalyst based on modified poly (styrene-alt-maleic anhydride) (MPSAMA) in three steps was fabricated. Then, the MPSAMA surface was modified using chlorosulfonic acid (CAS) to achieve a sulfonated MPSAMA (SMPSAMA) with high acidity and efficiency. FT-IR spectroscopy, CHNS analysis, FESEM, and TGA were employed to characterize the prepared nanocatalyst. The catalytic activity of the SMPSAMA was examined for the formation of the polyhydroquinoline derivatives through Hantzsch condensation and the synthesis of 2-amino-4H-chromene derivatives. This new heterogeneous nanocatalyst has been efficiently used for the synthesis of bifunctional bis polyhydroquinoline, and new alkylene bridging bis 2-amino-5-oxo-5,6,7,8-tetrahydro-4H-benzo[b]pyran derivatives.


Catalysts ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 478 ◽  
Author(s):  
Alex de Nazaré de Oliveira ◽  
Erika Tallyta Leite Lima ◽  
Eloisa Helena de Aguiar Andrade ◽  
José Roberto Zamian ◽  
Geraldo Narciso da Rocha Filho ◽  
...  

The present work was aimed to investigate the catalytic activity of a mesoporous catalyst synthesized from 3-mercaptopropyltrimethoxysilane (MPTS) functionalized Amazonian flint kaolin in the acetylation of eugenol with acetic anhydride. Materials were characterized by thermogravimetry (TGA), N2 adsorption (BET), X-ray dispersive energy spectroscopy (EDX), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and acid-base titration. The results presented proved the efficiency of flint kaolin as an alternative source in the preparation of mesoporous materials, since the material exhibited textural properties (specific surface area of 1071 m2 g−1, pore volume of 1.05 cm3 g−1 and pore diameter of 3.85 nm) and structural properties (d100 = 4.35 nm, a0 = 5.06 nm and Wt = 1.21 nm) within the required and characteristic material standards. The catalyst with the total amount of acidic sites of 4.89 mmol H+ g−1 was efficient in converting 99.9% of eugenol (eugenol to acetic anhydride molar ratio of 1:5, 2% catalyst, temperature and reaction time 80 °C and 40 min reaction). In addition, the reused catalyst could be successfully recycled with 92% conversion activity under identical reaction conditions.


Sign in / Sign up

Export Citation Format

Share Document