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1.
In this study, transesterification of soybean oil to biodiesel using CaO as a solid base catalyst was studied. The reaction mechanism was proposed and the separate effects of the molar ratio of methanol to oil, reaction temperature, mass ratio of catalyst to oil and water content were investigated. The experimental results showed that a 12:1 molar ratio of methanol to oil, addition of 8% CaO catalyst, 65 °C reaction temperature and 2.03% water content in methanol gave the best results, and the biodiesel yield exceeded 95% at 3 h. The catalyst lifetime was longer than that of calcined K2CO3/γ-Al2O3 and KF/γ-Al2O3 catalysts. CaO maintained sustained activity even after being repeatedly used for 20 cycles and the biodiesel yield at 1.5 h was not affected much in the repeated experiments. 相似文献
2.
Hongbin Ma Shufen Li Boyang Wang Ruihong Wang Songjiang Tian 《Journal of the American Oil Chemists' Society》2008,85(3):263-270
The heterogeneous base catalyst, γ-Al2O3 loaded with KOH and K (K/KOH/γ-Al2O3) was first prepared and used in the transesterification of rapeseed oil with methanol to produce biodiesel. The prepared
catalyst was characterized by X-ray diffraction, scanning electron microscopy, Brunauer–Emmett–Teller method, infrared spectroscopy
and X-ray photoelectron spectroscopy. It was found that when γ-Al2O3 is loaded with KOH and K, the Al–O–K species is produced, resulting in an increase in the catalytic activity. The impacts
of catalyst preparation conditions on the catalytic activities of K/KOH/γ-Al2O3 were investigated. The results demonstrate that the catalyst K/KOH/γ-Al2O3 has high catalytic activity when the added amounts of KOH and K are 20 and 7.5 wt% respectively. The transesterification
of rapeseed oil to biodiesel with the prepared heterogeneous base catalyst was optimized. It was found that the yield of biodiesel
can reach as high as 84.52% after 1 h reaction at 60°C, with a 9:1 molar ratio of methanol to oil, a catalyst amount of 4 wt%,
and a stirring rate of 270 g. 相似文献
3.
Nitikon Wongwaranon Okorn Mekasuwandumrong Piyasan Praserthdam Joongjai Panpranot 《Catalysis Today》2008,131(1-4):553
Nanocrystalline α-Al2O3 and Ni-modified α-Al2O3 have been prepared by sol–gel and solvothermal methods and employed as supports for Pd catalysts. Regardless of the preparation method used, NiAl2O4 spinel was formed on the Ni-modified α-Al2O3 after calcination at 1150 °C. However, an addition of NiO peaks was also observed by X-ray diffraction for the solvothermal-made Ni-modified α-Al2O3 powder. Catalytic performances of the Pd catalysts supported on these nanocrystalline α-Al2O3 and Ni-modified α-Al2O3 in selective hydrogenation of acetylene were found to be superior to those of the commercial α-Al2O3 supported one. Ethylene selectivities were improved in the order: Pd/Ni-modified α-Al2O3–sol–gel > Pd/Ni-modified α-Al2O3-solvothermal ≈ Pd/α-Al2O3–sol–gel > Pd/α-Al2O3-solvothermal Pd/α-Al2O3-commerical. As revealed by NH3 temperature program desorption studies, incorporation of Ni atoms in α-Al2O3 resulted in a significant decrease of acid sites on the alumina supports. Moreover, XPS revealed a shift of Pd 3d binding energy for Pd catalyst supported on Ni-modified α-Al2O3–sol–gel where only NiAl2O4 was formed, suggesting that the electronic properties of Pd may be modified. 相似文献
4.
Xu Li Guanzhong Lu Yanglong Guo Yun Guo Yanqin Wang Zhigang Zhang Xiaohui Liu Yunsong Wang 《Catalysis communications》2007,8(12):1969-1972
A novel solid superbase catalyst of Eu2O3/Al2O3 was prepared and its basic strength reached 26.5 measured by indicators according to Hammett scale. The catalytic activity of Eu2O3/Al2O3 was evaluated for the transesterification of soybean oil with methanol to biodiesel in the fixed bed reactor and under atmospheric pressure. The results show that Eu2O3/Al2O3 is an excellent catalyst for the transesterification of soybean oil, and the conversion of soybean oil can reach 63.2% at 70 °C for 8 h. 相似文献
5.
Pingmei Guo Fenghong Huang Mingming Zheng Wenlin Li Qingde Huang 《Journal of the American Oil Chemists' Society》2012,89(5):925-933
Magnetic solid base catalysts were prepared by loading Na2SiO3 on Fe3O4 nano-particles with Na2O·3SiO2 and NaOH as precipitator. The catalysts were used to catalyze the transesterification reactions for the production of fatty
acid methyl esters (FAME, namely biodiesel) from cottonseed oil. The optimum conditions of the catalysts' preparation and
transesterification reactions were investigated by orthogonal experiments. The catalyst with the highest catalytic activity
was obtained when Si/Fe molar ratio of 2.5, aging time of 2 h, calcination temperature of 350 °C, calcination time of 2.5 h.
Magnetic of the catalyst was characterized with Vibrating Sample Magnetometer (VSM) and transmission electron microscopy photograph
(TEM), and the results showed the catalyst Na2SiO3/Fe3O4 had good specific saturation magnetization and paramagnetism, and its water resistance was better than the traditional homogeneous
base catalysts; under the transesterification conditions of methanol/oil molar ratio of 7:1, catalyst dosage of 5%, reaction
temperature of 60 °C, reaction time of 100 min and stirring speed of 400 rpm, yield of biodiesel was 99.6%. The lifetime and
recovery rate of the magnetic solid base catalyst were much better than those of Na2SiO3. 相似文献
6.
Shayan Jalalmanesh Mohammad Kazemeini Mohamad H. Rahmani Milad Zehtab Salmasi 《Journal of the American Oil Chemists' Society》2021,98(6):633-642
Kaolin clay material was loaded with potassium carbonate by impregnation method as a novel, effective, and economically heterogeneous catalyst for biodiesel production of sunflower oil via the transesterification reaction. The structural and chemical properties of the produced catalysts were characterized through several analyses including the X-ray diffraction, scanning electron microscopy, Fourier-transform infrared spectroscopy, and Brunauer–Emmett–Teller specific surface area. These revealed the best catalyst for the investigated reaction among different ones prepared based upon various impregnation extent of the potassium carbonate. The influence of this parameter was examined through a comparison of the catalytic activity of differently produced catalysts. The impregnation amount of 20 wt% K2CO3 upon the kaolin achieved the highest catalytic activity attributed to its highest basicity. To expand upon the efficiency of transesterification, such reaction parameters including the molar ratio between methanol and oil, reactor loading of the catalyst, and time duration of the reaction were optimized. The highest yield of biodiesel over the K2O/kaolin catalyst was around 95.3 ± 1.2%, which was achieved using the kaolin support impregnated with 20 wt% of K2CO3 under optimum reaction conditions of the catalyst, reactor loading of 5 wt%, reaction temperature of 65 °C, methanol:oil molar ratio of 6:1, and reaction duration time of 4 hours. Ultimately, this optimized catalyst was demonstrated to successfully withstand the aforementioned optimum criteria up to five consecutive reaction cycles while experiencing a rather negligible loss of about 10% of its activity. 相似文献
7.
Guoyi Bai Xinxin Fan Hailong Wang Jianzhong Xu Fei He Huisen Ning 《Catalysis communications》2009,10(15):2031-2035
Co-precipitation, impregnation and ultrasonic sol–gel (USG) methods have been used to prepare Cu–Cr–Fe/γ-Al2O3 catalysts, which were further used to synthesize 2-methylpiperazine. The catalysts were characterized by XRD, XPS, TG/DSC, BET, TPR, AAS and TEM. It is found that preparation method can greatly impact the catalytic performance of the catalysts, the Cu–Cr–Fe/γ-Al2O3 catalyst prepared by the ultrasonic sol–gel method proved to be the most active and stable for this reaction. The dispersion and stabilization of Cu0 in the reduced catalysts are attributed to the existence of CuCr2O4 and Fe2O3. A surprising copper migration was detected by XPS analysis for the Cu–Cr–Fe/γ-Al2O3-USG catalyst after the calcination process, which may be crucial to the high activity and stability of this catalyst. 相似文献
8.
Fatty acid methyl esters, derived from vegetable oils or animal fats and better known as biodiesel, have received considerable attention because of their environmental benefits and the limited resources of fossil fuels. Most biodiesel is usually produced by the transesterification of vegetable oils with methanol in the presence of a catalyst. This study reports on the preliminary results of using alkaline earth metal-doped zinc oxide as a heterogeneous catalyst for transesterification of soybean oil. The highest catalytic activity was obtained with ZnO loaded with 2.5 mmol Sr(NO3)2/g, followed by calcination at 873 K for 5 h. When the transesterification reaction was carried out at reflux of methanol (338 K), with a 12:1 molar ratio of methanol to soybean oil and a catalyst amount of 5 wt.%, the conversion of soybean oil was 94.7%. Besides, tetrahydrofuran (THF), when used as a co-solvent, could increase the conversion up to 96.8%. However, the recovered catalyst exhibited the lower catalytic activity with a conversion of soybean oil of 15.4%. Furthermore, DTA-TG, IR and the Hammett indicator method were employed for the catalyst characterizations. 相似文献
9.
D. Martín Alonso R. Mariscal R. Moreno-Tost M.D. Zafra Poves M. Lpez Granados 《Catalysis communications》2007,8(12):2074-2080
A K/γ-Al2O3 catalyst was prepared using the wet impregnation method with K2CO3 as a precursor salt. During the activation process, a clear interaction between potassium carbonate-derived species and the support took place resulting in the formation of K aluminate-like species, as observed by evolved gas analysis by mass spectrometry (EGA-MS) and infrared spectroscopy (FTIR). This catalyst was tested in the transesterification of sunflower oil with methanol, achieving a methyl ester yield close to 100% after 1 h. However, when it was used in successive runs the catalyst showed a strong decrease in its catalytic performance. It is established experimentally that the performance in the first run was mainly due to a homogeneous contribution from active basic species dissolved in methanol. The leaching of potassium species in the reaction media was not avoided although a clear interaction between active phase and support was observed. The present work stresses the obligation of the reutilization and of the verification of the leaching of active species in analogous catalytic systems based on alkaline and alkaline-earth metal oxides when used in the transesterification reaction with methanol. 相似文献
10.
N. Escalona R. García G. Lagos C. Navarrete P. Baeza F.J. Gil-Llambías 《Catalysis communications》2006,7(12):1053-1056
Dibenzothiophene (DBT) hydrodesulphurization (HDS) reaction at 3 MPa and 325–375 °C on Mo/γ-Al2O3 single-bed and Me/γ-Al2O3//SiO2//Mo/γ-Al2O3 (Me = Co or Ni) double-bed catalysts were investigated. Results indicate that ratio cyclohexylbenzene (CHB)/biphenyl (BP) or selectivity is higher when using double-beds rather than a single-bed. Synergy in dibenzothiophene hydrodesulphurization on Co//Mo and Ni//Mo double-beds is also detected. Changes in selectivity and conversion are attributed to the action of spillover hydrogen (Hso) formed in the first bed that reaches the second bed. 相似文献
11.
Masoud Zabeti Wan Mohd Ashri Wan Daud Mohamed Kheireddine Aroua 《Applied Catalysis A: General》2009,366(1):154-159
In this work the response surface methodology (RSM) in conjunction with the central composite design (CCD) were used to optimize the activity of CaO/Al2O3 solid catalysts for the production of biodiesel. In order to measure the catalyst activity, we used palm oil as a representative raw material for the conversion to biodiesel. The biodiesel production was carried out in a batch laboratory scale reactor. The results showed that both the calcination temperature and the amount of calcium oxide loaded on the support had significant positive effects on the biodiesel yield. The maximum basicity and biodiesel yield obtained were about 194 μmol/g and 94%, respectively. Overall, the catalyst showed high performance at moderate operating conditions and its activity was maintained after two cycles. 相似文献
12.
Abstract
An effective heterogeneous catalyst, CaxMg2−xO2, was prepared and tested for soybean oil transesterification with methanol. The catalysts were characterized by using X-ray diffraction , Fourier transform infrared spectra, thermo gravimetric and differential thermal analysis , and Hammett indicator method. The catalyst with Ca/Mg ratio of 1.0 and calcined at 800 °C exhibited high catalytic activities. Under the suitable transesterification conditions (methanol/oil ratio 12:1, catalyst loading 6 wt%, reaction time 5 h, at reflux of methanol), the oil conversion of 91.3% could be achieved. The catalyst can be easily recovered and reused without significant deactivation. 相似文献13.
Biodiesel is a green fuel which can replace diesel while addressing various issues such as scarcity of hydrocarbon fuels and environmental pollution to an extent. The high production cost of biodiesel and the recovery of the catalyst after the transesterification process are the major challenges to be addressed in biodiesel production. In the present work, a cheap and promising solid base oxide catalyst was synthesized from chicken eggshell by calcination at 900 °C forming catalyst eggshells (CES) and was impregnated with the nanomagnetic material (Fe3O4) to obtain Fe3O4 loaded catalytic eggshell (CES–Fe3O4). Fe3O4 nanomaterials were synthesized by co-precipitation method and were loaded in catalytic eggshell by sonication, for better recovery of the catalyst after transesterification process. CES–Fe3O4 material was characterized by Thermogravimetric analysis, X-ray diffraction, Fourier transform infrared spectroscopy, a vibrating-sample magnetometer, Brunauer-Emmett-Teller, Dynamic light scattering, and Scanning electron microscopy. Biodiesel was synthesized by transesterification of Pongamia pinnata raw oil with 1:12 oil to methanol molar ratio and 2 wt% catalyst loading for 2 h at a temperature of 65 °C and yields were compared. The reusability of the catalyst was studied by the transesterification of the raw oil and its catalytic activity was found to be retained up to 7 cycles with a yield of 98%. 相似文献
14.
15.
Response surface methodology (RSM) based on central composite design (CCD) was used to optimize the three important reaction variables — methanol/oil molar ratio (x1), reaction time (x2) and amount of catalyst (x3) for production of biodiesel from palm oil using KF/ZnO catalyst. Based on the CCD, a quadratic model was developed to correlate the reaction variables to the biodiesel yield. From the analysis of variance (ANOVA), the most influential factor on the experimental design response was identified. The predicted yield after process optimization was found to agree satisfactory with the experimental value. The optimum conditions for biodiesel production were found as follows: methanol/oil ratio of 11.43, reaction time of 9.72 h and catalyst amount of 5.52 wt%. The optimum biodiesel yield was 89.23%. 相似文献
16.
Aijun Duan Ruili Li Guiyuan Jiang Jinsen Gao Zhen Zhao Guofu Wan Dengqian Zhang Weiqiang Huang Keng H. Chung 《Catalysis Today》2009,140(3-4):187
TiO2-Al2O3 binary oxide supports were obtained by sol–gel methods from Tetra-n-butyl-titanate and pseudoboehmite/aluminium chloride resources. The typical physico-chemical properties of NiW/TiO2-Al2O3 catalysts with different TiO2 loadings and their supports were characterized by means of BET, XRD and UV–vis DRS, etc. The BET results indicated that the specific surface areas of NiW/TiO2-Al2O3 catalysts were as higher as that over pure γ-Al2O3 support, and the pore diameters were also large. The XRD and UV–vis DRS analyzing results showed that the Ti-containing supported catalysts existed as anatase TiO2 species and the incorporation of TiO2 could adjust the interaction between support and active metal, and impelled the higher reducibility of tungsten. The hydrodesulphurization (HDS) performance of the series catalysts were evaluated with diesel feedstock in a micro-reactor unit, and the HDS results showed that NiW/TiO2-Al2O3 catalysts exhibited higher activities of ultra deep hydrodesulphurization of diesel oil than that of NiW/Al2O3 catalyst. The optimal TiO2 content of NiW/TiO2-Al2O3 catalysts was about 15 m%, and the corresponding HDS efficiency could reach to 100%. The sulphur contents of diesel products over NiW/TiO2-Al2O3 (from pseudoboehmite/AlCl3) catalysts with suitable TiO2 content could be less than 15 ppmw, which met the sulphur regulation of Euro IV specification of ultra clean diesel fuel. 相似文献
17.
Shuli Yan Manhoe Kim Steven O. Salley K.Y. Simon Ng 《Applied Catalysis A: General》2009,360(2):163-170
Investigations were conducted on a series of calcium and lanthanum oxides catalyst for biodiesel production. Mixed oxides catalyst showed a superior transesterification activity over pure calcium or pure lanthanum oxide catalysts. The catalyst activity was correlated with surface basicity and specific surface areas. The effects of water and free fatty acids (FFA) levels in oil feedstock, water and CO2 in air, mass ratio of catalyst, molar ratio of oil to methanol, and reaction temperature on fatty acid methyl ester (FAME) yield were investigated. Under optimal conditions, FAME yields reached 94.3% within 60 min at 58 °C. Mixed CaO-La2O3 catalyst showed a high tolerance to water and FFA, and could be used for converting pure or diluted unrefined/waste oils to biodiesel. 相似文献
18.
The purpose of the work to study biodiesel production by transesterification of Jatropha oil with methanol in a heterogeneous system, using alumina loaded with potassium nitrate as a solid base catalyst. Followed by calcination, the dependence of the conversion of Jatropha oil on the reaction variables such as the catalyst loading, the molar ratio of methanol to oil, reaction temperature, agitation speed and the reaction time was studied. The conversion was over 84% under the conditions of 70 °C, methanol/oil mole ratio of 12:1, reaction time 6 h, agitation speed 600 rpm and catalyst amount (catalyst/oil) of 6% (w). Kinetic study of reaction was also done. 相似文献
19.
In recent years, vegetable oils, as renewable raw materials, became a promising feedstock for chemicals and biodiesel production. The main products derived from oils are esters of fatty acids, especially methyl esters, obtained by their transesterification with methanol, in presence of acid or alkaline catalysts. The use of such catalysts implies the need for washing operations, which leads to environmental pollution. In the present paper, the response surface methodology based on a central composite design, has been developed to optimize the process of transesterification of corn oil. Ba(OH)2 in presence of diethyl ether was used as catalyst. A quadratic polynomial equation was obtained. It correlates the reaction parameters [methanol/oil molar ratio (x r), reaction time (x t) and catalyst concentration (x c)] with methyl esters yield. Analysis of variance analysis showed that only methanol/oil molar ratio and catalyst concentration have had the most significant influences on the conversion. The maximum methyl esters yield was obtained using the following optimum parameters: methanol/corn oil ratio of 11.32, reaction time of 118 min and catalyst concentration of 3.6 wt%. 相似文献
20.
M.A. Olutoye 《Fuel Processing Technology》2010,91(6):653-659
The Mg-Zn interaction effect of KyMg1 − xZn1 + xO3 heterogeneous type catalyst and its performance on transesterification of palm oil have been studied using the response surface methodology and the factorial design of experiments. The catalyst was synthesized using the co-precipitation method and the activity was assessed by transesterification of palm oil into fatty acid methyl esters. The ratio of the Mg/Zn metal interaction, temperature and time of calcination were found to have positive influence on the conversion of palm oil to fatty acid methyl ester (FAME) with the effect of metal to metal ratio and temperature of calcination being more significant. The catalytic activity was found to decrease at higher calcination temperature and the catalyst type K2Mg0.34Zn1.66O3 with Mg/Zn ratio of 4.81 gave FAME content of 73% at a catalyst loading of 1.404 wt.% of oil with molar ratio of methanol to oil being 6:1 at temperature of 150 °C in 6 h. A regression model was obtained to predict conversions to methyl esters as a function of metal interaction ratio, temperature of calcination and time. The observed activity of the synthesized catalyst was due to its synergetic structure and composition. 相似文献