Sodium Methoxide Catalyst Research Articles

Unique fatty acid composition of coriander seed biodiesel

Biodiesel is a renewable and environmentally friendly alternative fuel that can be used in diesel engines without modification. In this study, biodiesel production from coriander seed oil obtained through a two-stage transesterification process using the cold pressing method was carried out in the Konya region. First, the oil's acid value was reduced through acid-catalyzed pretreatment to form coriander seed oil methyl esters, and then biodiesel was produced using standard transesterification with methanol and sodium methoxide catalyst. Coriander (Coriandrum sativum) contains an unusual fatty acid not previously reported as a major component in biodiesel fuels: petroselinic acid (6Z-octadecenoic acid; 68.5% by weight). Coriandrum sativum seed oil methyl ester was evaluated to have properties suitable for diesel engines, complying with EN 14214 and ASTM D6751 standards, with a unique fatty acid composition and excellent oxidative stability.

Formulasi campuran olein minyak sawit untuk memproduksi shortening bebas lemak trans [Formulation of palm oil olein mixture to produce trans-fat-free shortening

Shortening is a solid fat with the functional properties needed to produce a better texture and appearance for bakery or confectionery products, as well as frying and cooking media. Shortening is made by mixing two or more vegetable oils and then modifying them through a chemical or enzymatic interesterification process. In this research, the raw material for shortening was prepared from a mixture of 2 types of palm oil olein: refined olein (ROL) and mid olein (MOL). This research aimed to determine the optimal ROL and MOL mixture ratio in the chemical interesterification process, which produces shortening with the best quality and specifications. Five levels of ROL/MOL comparison consisting of (100/0), (95/5), (90/10), (85/15), and (80/20) were chemically inter-esterified using a sodium methoxide catalyst under a vacuum of 0.8 bar at a temperature of 110 oC and speed of 500 rpm. The results showed that the increase of MOL in the ROL/MOL formulation tends to increase the shortening melting point. However, increasing MOL did not change the iodine value, and all the ROL/MOL ratios produced shortening with specifications that met the SNI 3718:2018 requirement, and the best ROL/MOL ratio was 80/20.

Synthesis and characterization of N-acyl alkanolamide surfactant from fatty acids and alcohol amines using sodium methoxide catalyst

Surfactant is a substance added to the liquid that improves the spread's properties by weakening the liquid's surface voltage. Surfactants have a molecular structure consisting of hydrophilic groups and hydrophobic groups. Surfactant needs in Indonesia continue to increase along with the development of industries in Indonesia. This study will be synthesized by the N-acyl surfactant alkanolamide using one type of alcohol amine, namely diethanolamine, through a reaction of amidation between fatty acids and using organic solvents tert-amyl alcohol. The catalyst used is a chemical catalyst, namely sodium methoxide. Furthermore, the purpose of this research is to determine the effect of reaction variables and determine the characteristics of the N-acyl alkanolamide surfactant in the form of acidic numbers and spreading numbers. This study showed for lauric acid, palmitate acid, and the best stearate acid at 90 oC reaction temperatures and 2-hour reaction times, while the best succinic acid at 100 oC and a reaction time of 2 hours. The relationship between reaction rate and time is directly proportional; the longer the reaction time, the higher the rate. The conversion relationship with reaction time is directly proportional, where conversion will increase with the increase in reaction time. However, this does not happen to all fatty acids. Due to the increase in reaction time, it will not provide significant results on surfactant products. The relation between the reaction temperature and the conversion acquisition at the time obtained decreased along with the increase in reaction temperatures. The acid numbers in the best conditions in a row are 40.67 for N-palmitoyl diethanolamine, 47.41 for N-lauroyl diethanolamine, 63.11 for N-succinyl diethanolamine, and 22.44 for N-stearoyl diethanolamine. The saponification number in the best conditions in a row is 36.47 for N-palmitoyl diethanolamine, 23.84 for N-lauroyl diethanolamine, 57.50 for N-succinoyl diethanolamine, and 7.01 for N-stearoyl diethanolamine.

Enhancing the Catalytic Activity of Eggshell-Derived CaO Catalyst and Its Application in Biodiesel Production from Waste Chicken Fat

The comparatively greater cost of producing biodiesel in comparison to petroleum diesel is one of the key drawbacks. Eggshells and leftover chicken fat are examples of poultry wastes that can be used to produce biodiesel at a low cost as catalysts and oil, respectively. In this study, eggshell-derived CaO and its doping with sodium methoxide catalyst for enhancing catalytic activity was synthesized for the transesterification of waste chicken fat and characterized by FT-IR and XRD analyses. XRD studies confirmed the crystalline structure of the developed catalyst and doping of sodium with eggshell-derived CaO. The transesterification reaction was performed at different reaction parameters such as the catalyst loading, the methanol to oil ratio, the reaction temperature, and the reaction time. The biodiesel produced at the maximum yield was evaluated by gas chromatography mass spectrometry analysis. A maximum yield of 96% biodiesel was obtained with catalyst loading of 2 wt% of oil, as well as a methanol to oil ratio of 13:1 at 60 °C in 1 h. The output demonstrates that eggshell waste is a potentially accessible source of biomass-derived nano catalyst for the synthesis of biodiesel using chicken fat as a feedstock.

Optimization and effect of varying catalyst concentration and trans-esterification temperature on the yield of biodiesel production from palm kernel oil and groundnut oil

The negative environmental impact generated by fossil fuel has resulted in the demand to search for alternative routes of renewable sources of energy, such as biodiesel, that have unlimited duration while having little or no hazardous impact. In this study, trans-esterification of palm kernel oil and groundnut oil was carried out using sodium methoxide (CH3ONa) as a catalyst. The effect of varying Sodium Methoxide (CH3ONa) catalyst concentrations of (0.25, 0.5, 1.0, 1.5, and 2.0) % w/v at trans-esterification temperatures of (50, 55, and 60) oC on the yield of biodiesel from groundnut oil and palm kernel oil was determined. This was to identify the catalyst concentration and trans-esterification temperature with optimal process yield. The process gave optimum biodiesel yields of 98% and 84% by volume of groundnut oil and palm kernel oil at reaction conditions of 0.5%w/v CH3ONa as catalyst, trans-esterification temperature of 55oC, 360 rpm mixing rate and a reaction time of 90 minutes. The biodiesel produced was analyzed for fuel properties using the ASTM standard, and the results obtained were as follows; specific gravity (0.8835, 0.8815 at 15oC), flash point (98, 124) oC, and viscosity (5.2, 7.6) mm2S-1 for palm kernel oil and groundnut oil respectively.

Kinetics and thermodynamic analysis of transesterification of waste cooking sunflower oil using bentonite-supported sodium methoxide catalyst

Kinetics and thermodynamic analysis of transesterification of waste cooking sunflower oil using bentonite-supported sodium methoxide catalyst

Interesterification of mafura butter and camellia oil for cosmeceutical formulations: Chemical composition and physicochemical properties of products

Mafura butter (MB) obtained from seeds of Trichilia emetica Vahl is widely used in traditional cosmetic formulations throughout Southern Africa. It is gaining increasing popularity in the modern cosmetic industry due to growing consumer demand for natural cosmetics. However, the butter has a high melting point and low spreadability, which limits its emollient properties. In the present study, MB was chemically and enzymatically interesterified with camellia oil (CO, Camellia oleifera C.Abel) at different ratios (90:10, 80:20, 70:30, 60:40 and 50:50 w/w) to produce formulations with improved physicochemical and cosmeceutical properties. Chemical interesterification (CI) was performed using sodium methoxide catalyst, while enzymatic interesterification (EI) was carried out with three different immobilized enzymes, including Lipozyme® TL IM, Lipozyme® RM IM and Lipozyme® 435. The original and interesterified blends were examined for fatty acid (FA) and triglycerides compositions, slip melting point (SMP), solid fat content (SFC), tocopherol and sterol contents, toxic heavy metal contents, radical scavenging activity (RSA) and in vitro ultraviolet radiation protection ability. Both CI and EI reduced SMP and SFC of interesterified products, resulting in products with improved consistency. Interesterification distributed cosmeceutically relevant unsaturated FA such as oleic acid, linoleic acid and linolenic acid in the products, depending on the ratios of MB and CO. The tocopherol and phytosterol contents in MB was 495.08 ± 19.02 and 842.61 ± 35.77 μg/g, respectively, while it was 438.6 ± 20.89 and 163.57 ± 20.47 μg/g, respectively in CO. The CI dramatically reduced the tocopherol contents up to 50 % in the products, while EI did not affect its content significantly. The ICP-MS analysis revealed that MB, CO and interesterified products does not contain toxic metals such as Sn and Hg, while Cr (< 0.18 ppm) and Pb (< 0.14 ppm) were present within the acceptable limits. Interesterified products showed promising RSA (with IC50 values in the range of 10.15 ± 0.79–12.30 ± 1.15 mg/mL), however, had a low in vitro sun protection factor (SPF < 0.2).

Experimental studies on sodium methoxide supported bentonite catalyst for biodiesel preparation from waste sunflower oil

AbstractClays are abundantly available support material used for the preparation of green heterogeneous catalysts to produce biodiesel. In the present study, bentonite clay supported on sodium methoxide catalyst was prepared by impregnation process. The catalyst characterization was done by powder X‐ray diffraction, brunauer–emmett–teller analysis, thermo‐gravimetric analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, atomic absorption spectroscopy, and Hammett indicator techniques. The study for determination of optimal parameters in biodiesel production was carried out using response surface methodology. A biodiesel yield of 94.33% was achieved with 2 wt% catalyst amount, 12:1 M ratio of methanol to oil, 70 min reaction time at 55°C. It was observed that the prepared catalyst has good catalytic activity. An additional significance of the synthesized catalyst was that it could be easily recovered and used in consecutive cycles without any substantial loss of catalytic activity. The physical and chemical fuel properties were determined and met the American Society for Testing and Materials Standard.

Modeling of process intensification of biodiesel production from Aegle Marmelos Correa seed oil using microreactor assisted with ultrasonic mixing.

Conventionally, the batch type reactors were used for the production of biodiesel. However, in recent years, the usage of microreactors has started emerging as a significant substitute for biodiesel production due to its higher conversion rate at a short duration. These microreactors have a significantly high surface to volume ratio and high heat-mass transfer rate. The disadvantage of this type of reactors is its low mixing rate of the reagents. This can be overcome with the assistance of ultrasonic mixing. The main objective of this paper is to study the interlaced effect of a continuous flow microreactor and ultrasonic mixing on trans-esterification of Aegle Marmelos Correa seed oil using sodium methoxide catalyst. Results of microreactors with 0.3 mm and 0.8 mm diameter were compared. The effects of process parameters namely, flow rate (2-10 mL/min), reaction temperature (45-65 °C), catalyst amount (0.5-2.5 wt%), oil to methanol molar ratio (1:6-1:18) and ultrasonic mixing time (30-150 s) were studied using response surface methodology (RSM). The biodiesel yield of 98% and 91.8% were obtained for 0.3 mm and 0.8 mm microreactors, respectively. The maximum biodiesel yield observed in 0.3 mm reactor under following optimum conditions: 6.8 mL/min flow rate, 48 °C reaction temperature, 1.3 wt% catalyst, 1:9 oil to methanol molar ratio and 83 s ultrasonic mixing time. The predictive and generalization abilities of RSM and artificial neural network (ANN) models were evaluated and compared. The study showed that ANN and RSM models could predict the yield with an R2 value of 0.9955 and 0.9900 respectively. However, the ANN model predicted the yield with the least mean square error value of 0.00001294, which is much lower than RSM.

Synthesis of 2-(4-Allyl-2-Methoxy Phenoxy)-N,N-Bis(2- Hydroxyethyl) Acetamide from the Transformation of Eugenol Isolated from Clove Oil

Eugenol as the main component of clove oil has been isolated through NaOH salting procedure followed by H2SO4hydrolysis, n-hexane partitioning and purification with vacuum distillation. 71% (v/v) eugenol was produced with purity of 97.70% based on gas chromatography analysis. 2-(4-allyl-2-methoxy phenoxy)-N,N-bis(2-hydroxyethyl) acetamide compound has the potential as antibacterial or substances for medicine in pharmaceutical can be synthesized from eugenol isolated through alkoxylation, esterification and followed by amidase. Alkoxylation was done using Williamson method through NaOH transformation of hydroxyl functional group in eugenol to form sodium eugenolate then with α-monochloroacetate substitution in reflux condition, eugenyl acetate was produced. The acid produced was extracted with ether/Na2CO3, followed by recrystallization using hot water and produced 70.52% solid form. Eugenyl acetate esterification with methanol in benzene solvent with H2SO4 catalyst in reflux condition produced methyl eugenol acetate liquid with 81.36% of yield. Amidase of methyl eugenol acetate with diethanolamine and sodium methoxide catalyst with methanol solvent in reflux condition. After purification, 2-(4-allyl-2-methoxy phenoxy)-N,N-bis(2-hydroxyethyl) acetamide compound in solid form is produced with 72.99% yield. Eugenol isolated, eugenyl acetate and methyl eugenol acetate had their structures analyzed with FT-IR spectroscopy while 2-(4-allyl-2-methoxy phenoxy)-N,N-bis(2-hydroxyethyl) acetamide compound was analysed using FT-IR and H1-NMR.

Sodium Methoxide Catalyzed Depolymerization of Waste Polyethylene Terephthalate Under Microwave Irradiation

Chemical recycling of polyethylene terephthalate (PET) to produce terephthalic acid (TPA) was studied using in situ hydrolysis with sodium methoxide in methanol and dimethyl sulfoxide (DMSO) as solvent under microwave irradiation. The microwave-assisted reaction was carried out at different temperatures, and reaction time between 5 to 30 min. High degrees of depolymerization were examined at temperature near 70°C at microwave power 300 W. The reaction was carried out in a sealed microwave reactor in which the time and temperature were controlled and recorded. The products were mainly monomers such as TPA and ethylene glycol (EG) which were isolated and purified for further analysis. Monomethyl terephthalate, dimethyl terephthalate, and terephthalic acid were formed initially then converted to TPA as a single monomer product. Purified, TPA was analyzed and identified by NMR, TGA, DSC and FTIR. It was observed that the reaction greatly depends on the amount of sodium methoxide, the volume of methanol and DMSO used, the reaction time, and temperature. Compared to conventional heating methods, the time needed to achieve complete degradation of PET was significantly reduced to 5 min by using microwave irradiation and sodium methoxide catalyst. This has led to substantial saving in energy and cost supporting the conclusion that this proposed recycling process is very beneficial for the recycling of PET wastes.

Process Optimization of Ethyl Ester Biodiesel Production from Used Vegetable Oil under Sodium Methoxide Catalyst and its Purification by Ion Exchange Resin

Production of ethyl ester biodiesel from a tranesterification reaction of used vegetable oil and ethanol was carried out using a sodium methoxide catalyst. Response surface methodology (RSM) was applied to investigate the effect of experimental factors on the fatty acid ethyl ester (FAEE) conversion. The design of the experiment involved a 5-level-4-factor central composite design and 30 runs were used to achieve the optimum percentage FAEE conversion that was determined by 1H-NMR. The coefficient of determination (R2) for the regression equation was 86.49% and the probability value (p&lt;0.05) demonstrated a very good fit for the regression model. The optimum conditions obtained from RSM were 4% v/v of catalyst, 35.61% v/v of ethanol-to-oil, at 43.70°C reaction temperature, and 75.45 min of reaction time. The produced ethyl ester biodiesel was further purified by wet washing compared with dry washing using ion exchange resin. The result showed that the purified biodiesel by wet washing met the EN standard but the dry washing out put did not but only for the acid value. The blending of 10% v/v of purified biodiesel obtained from dry washing with 90% v/v of petrodiesel could decrease the acid value to meet the EN standard.

Computational fluid dynamics investigation for austenitic AISI 904L stainless steel corrosion in a biodiesel stream piping

A Brazilian biodiesel plant uses the transesterification of soybean oils with the methanol and sodium methoxide catalyst excess to convert these oils into alkyl esters and glycerin. Hydrochloric acid solution is injected in the piping to neutralize free NaOH and reduce saponification of oils. After the hydrochloric acid solution, several failures of pipelines of AISI 316L and 904L steels were registered. The objective of this work is to study the austenitic stainless steel corrosion observed in the downstream piping the hydrochloric acid injection, applying computational fluid dynamics and to evaluate pH and chloride profiles using different geometries for the acid solution injection in order to avoid or mitigate the corrosive attack. The obtained results showed a good agreement with in situ observations of the pipe degradation. All the studied geometries presented evidence of a weak mixture between the polar and non‐polar species, even under turbulent flow. The elbow geometry is more effective to reduce the local corrosive attack compared to two other simulated geometries.

Castor oil modified by epoxidation, transesterification, and acrylation processes: Spectroscopic characteristics

ABSTRACTIn the present study, castor oil (CO) was modified by epoxidation, transesterification, and acrylation processes. In situ epoxidation method was used to prepare epoxidized castor oil (ECO) in acetic acid with hydrogen peroxide in the presence of Seralite SRC-120 catalyst. Transesterified epoxidized castor oil was synthesized from the reaction of methanol in the presence of sodium methoxide catalyst. The acrylated epoxidized castor oil was synthesized from the reaction of ECO with acrylic acid containing hydroquinone. Chemical structures of modified CO were analyzed by Fourier transform infrared spectroscopy and proton nuclear magnetic resonance spectra analysis.

Sodium Methoxide Catalyzed Depolymerization of Waste Polyethylene Terephthalate under Microwave Irradiation

Chemical recycling of polyethylene terephthalate (PET) to produce terephthalic acid (TPA) was studied using in situ hydrolysis with sodium methoxide in methanol and dimethyl sulfoxide (DMSO) as solvent under microwave irradiation. The microwave-assisted reaction was carried out at different temperatures, and reaction time between 5 to 30 min. High degrees of depolymerization were examined at temperature near 70 °C at microwave power 300 W. The reaction was carried out in a sealed microwave reactor in which the time and temperature were controlled and recorded. The products were mainly monomers such as TPA and ethylene glycol (EG) which were isolated and purified for further analysis. Monomethyl terephthalate, dimethyl terephthalate, and terephthalic acid were formed initially then converted to TPA as a single monomer product. Purified, TPA was analyzed and identified by NMR, TGA, DSC and FTIR. It was observed that the reaction greatly depends on the amount of sodium methoxide, the volume of methanol and DMSO used, the reaction time, and temperature. Compared to conventional heating methods, the time needed to achieve complete degradation of PET was significantly reduced to 5 min by using microwave irradiation and sodium methoxide catalyst. This has led to substantial saving in energy and cost supporting thus the conclusion that this proposed recycling process is very beneficial for the recycling of PET wastes.

Tannic acid-based tough hyperbranched epoxy thermoset as an advanced environmentally sustainable high-performing material

Bio-based resources are progressively replacing those of petroleum-based to address the detrimental impact on environment and health issues. In this regard, hyperbranched epoxy resins with three different compositions were synthesized by simple polycondensation reaction of bio-based branching reactant, diethanolamide of gallic acid with bisphenol-A, and epichlorohydrin. Diethanolamide of gallic acid was obtained from the reaction between tannic acid and diethanol amine in the presence of sodium methoxide catalyst. FTIR, 1H NMR, and 13C NMR spectroscopic analyses were employed to confirm the structure of branching unit and hyperbranched resins. Poly(amido amine)-cured hyperbranched epoxy thermosets exhibited superior properties, such as tensile strength (45–57.2 against 38.5 MPa), elongation-at-break (16.3–24.2 against 5 %), scratch hardness (>10 against 7 kg), toughness (577.8–859.1 against 150.2 MPa), tensile adhesive strength (1647–2086 against 581 MPa), and biodegradability (17.6–31 against 2.2 %), compared with the conventional bisphenol-A-based epoxy, prepared under the same conditions. These results simply indicate the advantageous of the bio-based moiety and hyperbranched architecture on the overall performance of the thermosets. Moreover, good antioxidative response of these thermosets expands their applications as protective coatings and adhesive materials. Thus, diethanolamide of gallic acid-based hyperbranched epoxy thermoset can be used as potent ecofriendly advanced material in multifaceted applications.

Study on Characteristics of Ricinoleic Acid as a Phase Change Material

Today the use of fatty acids as heat storage substance is growing. The use of several types of fatty acids such as oleic acid, palmitic acid, and stearic acid as heat storage materials has been studied. But, ricinoleic acid from castor oil has not been studied yet. This study was conducted to ascertain the characteristics of ricinoleic acid as a heat storage material.Methyl ricinoleic was obtained through transesterification of castor oil by methanol with sodium methoxide catalyst. Methyl ricinoleic was then hydrolyzed using sodium hydroxide in ethanol to produce ricinoleic acid. Ricinoleic acid was identified by FTIR (Fourier Transform Infrared Spectrophotometer) test standard ASTM E 1252-07 and its chemical composition was determined by Gas Chromatography-Mass Spectrometry (GC-MS). The identification of the type, amount, and environment of hydrogen in the compound was determined by Nuclear Magnetic Resonance (NMR). The analysis on characteristics, that is, transition and melting temperatures of material was performed by DSC (Differential Scanning Calorimetry) test standard ASTM D 3419-08.Based on the results of FTIR, GC-MS, 1H-NMR, dan 13C-NMR tests, the spectra that were obtained indicated that the test substances were methyl and ricinoleic acid 70.349%. And, the results of DSC tests indicated that the characteristics of ricinoleic acid absorbed and released latent heat at the temperature from 8.58°C and absorbed sensible heat at the temperature from-7.17°C to 8.58°C.

PENGARUH JENIS PELARUT DAN TEMPERATUR REAKSI PADA SINTESIS SURFAKTAN DARI ASAM OLEAT DAN n-METIL GLUKAMINA DENGAN KATALIS KIMIA

Surfactants are molecules that also has a hydrophilic group and a lipophilic group that can unify a mixture consisting of water and oil. Alkanolamide is one type of nonionic surfactants are widely used in everyday life. In this study, will be observed the influence of the type of solvent and reaction temperature on the synthesis of surfactant alkanolamide n -methyl glukamine and oleic acid from palm oil with sodium methoxide catalyst. This study aims to determine the value of the hydrophilic lipophilic balance (HLB), pH and surface tension of surfactant, by observing the effect of the type of solvent and reaction temperature. This research was conducted by using a flask at 90 ° C, 110 ° C, 130 ° C for 3 hours reaction time, substrate ratio of 1: 2, the stirring speed of 150 rpm and a catalyst concentration of 0.4% (w/w). In the amidation reaction samples taken from the flask every 1 hour for 3 hours and then the results of this amidation reaction was washed with acetone solvent to separate the catalyst. Results washing then purified by heating at 90°C to evaporate the solvent surfactant products hexane and butanol. Results containing surfactant in the analysis with Hydrophilic Liphophilic Balance Method, surface tension and FT-IR spectrophotometry. Based on this research, the optimal conditions at a temperature of 110oC, reaction time 3 hours at the solvent ratio 2: 1. From the analysis of surfactant oleoil n-Methyl glukamine values obtained HLB in the range of 11,53 HLB in accordance with the standard detergent.

Tetrahydrofuran-Assisted Transesterification Biodiesel from Waste Cooking Oil

Base-catalysed transesterification of waste cooking oil for the production of biodiesel was assisted by the addition of co-solvent tetrahydrofuran (THF). In addition to lowering of reaction temperature and reduction in reaction time for transesterification, THF facilitated production of methyl ester in a single phase. THF-assisted base-catalysed reaction was optimised for various parameters. Maximum biodiesel production (92.8%) was obtained with 4% THF, 0.6% sodium methoxide (catalyst), 6:1 methanol-to-oil ratio, 45 min reaction time and 50°C reaction temperature. Added to this, maximum glycerol recovery (18.62%) was obtained at 50°C using lower concentrations of THF (2%). Use of THF highlights even more economically viable and greener potential for biodiesel production as this co-solvent is non-toxic, un-reactive and of biomass origin.

Transesterification of sunflower oil with ethanol using sodium ethoxide as catalyst. Effect of the reaction conditions

Typically, biodiesel is produced using vegetable oil and methanol as raw materials, and sodium methoxide as catalyst, whereupon the obtained product is composed of methyl esters. However, the use of ethyl esters as biodiesel presents many advantages compared to the methyl esters. In this work, the transesterification with ethanol to produce ethyl esters using sodium ethoxide as catalyst was studied. The effect of temperature and alcohol and catalyst concentration on the reaction conversion was investigated, in order to optimize these parameters while also meeting the quality standards.It was found that the optimal reaction conditions are: 1.6wt.% sodium ethoxide, 25v/v% ethanol and 55°C, which allow obtaining a biodiesel composed 100% by ethyl esters that complies with the international quality standards. On the other hand, it was observed that methanolysis reactions are faster than the ethanolysis and sodium methoxide catalyst is more active than the corresponding ethoxide, due to the higher steric hindrance of the ethoxi-radical and to the more intense saponification of sodium ethoxide in ethanol medium.