Preparation of novel biodiesel

Thread Content

Preparation of new biodiesel: China is a country with scarce petroleum resources. In recent years, with the rapid growth of the automobile industry, China’s oil reserves have been decreasing. At the current rate of consumption, oil will only last for over 40 years. Furthermore, since diesel engines burn through compression ignition, using petroleum-based diesel as fuel results in the generation of large amounts of harmful emissions, causing severe pollution to the atmospheric environment on which human life depends. Therefore, it is of great significance to develop new renewable fuels that are harmless to the environment. Plant oil is a potential alternative fuel for diesel cleaning, with triglycerides as its main component. However, due to its high viscosity, poor atomization properties, and tendency to clog, it is difficult to use directly in diesel engines. Converting vegetable oil into vegetable oil monoesters, namely bio-diesel, can overcome the shortcomings of vegetable oil. After transesterification with ordinary monohydric alcohols, the molecular chains of vegetable oils become shorter, their molecular weight decreases, their cetane number increases, and their viscosity drops; their key technical properties then become similar to those of diesel. Biodiesel possesses excellent environmental benefits; it is a renewable, oxygen-containing clean energy source that has become one of the topics of intense research interest. Biodiesel can be used as a biofuel as well as an additive for diesel engine fuel, and it can be applied to any diesel engine. The biodiesel that has been developed so far is mainly fatty acid monostearates obtained through an ester exchange reaction between animal and plant oils/fats and common monoalcohols (methanol, ethanol, propanol, and butanol). However, its low oxygen content makes it difficult to significantly improve the emission performance of diesel engines. In this experiment, ethylene glycol ether methyl acetate was used as a substitute for ordinary monohydric alcohols, along with refined… Date of receipt ； 2005—09—10 Date of revision: 2005—10—10 Author’s profile: Zhang Hongyun (born 1979), female, master’s degree holder. Research focus: New types of biodiesel. VIP Information: http://www.cqvip.com. Journal of Northwest Agriculture, Volume 15. Ethylene glycol ether was synthesized from edible soybean oil through transesterification reactions, resulting in a new type of biodiesel based on soybean oil monostearate. This biodiesel contains an additional ether group compared to traditional biodiesel, and thus combines the advantages of both ether and ester compounds; as a result, it has a high oxygen content and excellent emission properties. Furthermore, it has a high cetane number, resulting in better ignition properties, and is a typical green, clean oxygen-containing fuel. 1 Test Principle and Procedure CH OOCR 1 CHOOCRj+3NaOCH~CH2OCHzCHs— — — + l CH zOOCRi Raw materials used in the test: ethylene glycol ether (analytical grade, provided by the Chemical Reagents Branch of Tianjin Zongheng Xing Industry and Trade Co., Ltd.), Xiangmanyuan soybean oil (**Grade 1, provided by Xi’an Kerry Oil Industry Co., Ltd.), and metallic sodium (chemical grade, provided by Tiantai Chemical Reagents Factory in Dongli District, Tianjin). 1.2 Experimental Procedure: In a clean 1000 mL three-necked flask equipped with a thermometer and a stirring rod, 530 mL of pretreated soybean oil was added. The mixture was heated to 90°C in a water bath and kept at that temperature. Immediately thereafter, the freshly prepared sodium alkoxide solution (also heated to 90°C) was added under vigorous stirring; timing began at this point. Vigorous stirring continued during the deacidification process, followed by water removal.
1.1 Principle of the Experiment: An acid-catalyzed transesterification reaction is utilized, with metallic sodium serving as the catalyst. Ethylene glycol ether is used to replace the glycerol in soybean oil triglycerides, converting one triglyceride molecule into three long-chain fatty acid ethyl esters. This process reduces the molecular weight and increases fluidity. The simplified reaction equation is as follows: ； RlCOOCH2CH OCH2CH~ ∞ n R 2cooc~ CHeocH H| CHONa l RcooCHcH. CHcH N. Within 1 hour. After the reaction is complete, the solution in the flask is transferred to a 1,000 L separatory funnel, neutralized with hydrochloric acid solution (90°C), and left to stand for 24 hours. The solution in the lower layer of the separatory funnel consists mainly of glycerin and a small amount of soap. The upper layer of the solution was subjected to vacuum distillation to recover ethylene glycol ether; sodium soap was removed by suction filtration, followed by repeated washing (4–7 times) and drying, yielding a pale yellow, clear, and transparent product, which is biodiesel. The yield of the product in this experimental process is over 90%. The process flow for preparing ethylene glycol ether soybean oil ester is shown in Figure 1. Figure 1: The process of preparing biodiesel. Fig.1 shows the procedure for producing biodiesel using vegetable oils and soybean oil as raw materials. ×100% Experience_[3] – Appropriate experimental conditions were designed for conducting orthogonal experiments. The EQUINOX55 type Fourier-transform infrared spectrometer was used for the experiment, with four factors considered: alcohol-to-oil molar ratio (A), catalyst amount (B), reaction temperature (C), and reaction time (D). The photometer had a frequency range of 4000.31 cm⁻¹ to 399.259 cm⁻¹. The 3 levels selected for each factor are divided into cm; the infrared spectrum of the product is determined by KBr tablet compression ； Use the following ratios: A at 4:1, 6:1, and 8:1 ； B underwent nuclear magnetic spectroscopy analysis using 0.3 and 0.5 INOVA-type superconducting MRI scanners, as well as 0.79/5 ； C at 70 C, 90 C, and 110 C ； The solvent used for D at 30 min and 1 h was CDC1. , with TMS as the internal standard, and observation frequencies of 400 and 2 h. For 4 factors and 3 levels, an L(3) orthogonal table design can be used, considering Mf1. The indicator is the yield. A single-cylinder engine was used to study the soot emissions associated with the reaction yield of diesel engines after burning novel biodiesel – (mass of biodiesel/mass of refined soybean oil). Xiao, VIP Information: http://www.cqvip.com. Issue 1: Zhang Hongyun et al.: Preparation of new types of biodiesel. 2 Results and analysis. 2.1 Results of orthogonal experiments: Based on the values in Table 1, the range values are R1 = -33.0, R2 = 39.5, R3 = 19.5, and RI = -8.7. It can be seen that the main factors affecting the transesterification reaction are the amount of catalyst and the alcohol-to-oil molar ratio. The order of their influence is amount of catalyst > alcohol-to-oil molar ratio > reaction temperature > reaction time, that is, B > A > C > D; therefore, the optimal optimized experimental conditions are A and B. c D, that is, the molar ratio of alcohol to oil is 6:1, the amount of catalyst used is 0.5, the reaction temperature is 90°C, and the reaction time is 30 minutes. Table 1 Results of the I (3) orthogonal experiments and data analysis Table 1 Orthogonal experiments result and analysis Item A: Molar ratio of alcohol to oil; B: Amount of catalyst used; C: Reaction temperature/°C; D: Reaction time/s; E: Yield/% Item Molar ratio Catalyst amount Reaction temperature Reaction time Yield 1 4:1 0.3 70 0.5 70.3 2 4:1 0.5 90 1 81.6 3 4 ； 1 O．7 110 2 76．2 4 6 ； l 0．3 70 2 8o. 3 5 6:1 O.5 l1o O.5 95.3 6 6{l 0.7 90 l 85.5 7 8:1 0.3 1l0 l 69.9 8 8:1 0.5 90 2 83.1 9 8:1 0.7 70 0.5 8O.1 Ki K2 K3 R, 2.2 Factors affecting the transesterification reaction: The amount of catalyst used is one of the main factors that influence the transesterification reaction. During the transesterification reaction, if an insufficient amount of catalyst is used, the reaction time will be longer or the conversion rate will be low. An excessive amount of catalyst is used; too many basic sites can trigger saponification reactions, resulting in emulsification of the product, making it difficult to separate and complicating the post-treatment process. This also affects both yield and conversion rate ； The alcohol-to-oil molar ratio is another key factor affecting the transesterification reaction; an excessively high alcohol-to-oil molar ratio can severely affect the separation of glycerol and increase the costs associated with separation ； Temperature has a significant impact on the conversion rate of the transesterification reaction; low temperatures slow down the reaction and reduce the yield. As the temperature rises, the reactivity of the reactants increases, the reaction rate speeds up, which in turn leads to an increase in yield. However, excessively high temperatures will accelerate the evaporation of the alcoholic reactants, reducing the concentration of alcohol in the liquid phase and thus lowering the yield ； The effect of reaction time on the transesterification reaction is not significant. At the initial stage, as the reaction time increases, the yield rises markedly; however, after a certain period, the rate of the reverse reaction begins to increase rapidly and exceeds that of the forward reaction, causing the yield to decline again, before eventually stabilizing at a constant value. 2.3 Product structure analysis: The infrared spectrum is shown in Figure 2, and the explanation is provided in Table 2 ； The proton NMR spectra are shown in Figures 3 and 4. Infrared spectrum of the product obtained after storage, Fig. 2: FTIR spectrum of ethylene glycol monoethyl ether soyate. VIP Information: http://www.cqvip.com. Journal of Northwest Agriculture, Volume 15 ； il ： l i ： ：. e-l} OT: 01: Aluminum ≈ Arsenic… ‘ ‘ ⋯‘, 3 ports 2.8 2 2 4 2.2 2 ports 16 I.6 i.4 l 2 r d ppnl — _0 — — — — ~ — — — Hydrogen NMR spectrum of the product in Fig. 3: H NMR spectrum of ethylene glycol monoethyl ether soyate. 2004l2z2 0’ _ Continent: # g: Ding Sou ~ ~” ? Frequency: ‘Z mouth u1 1-maggots O Il O B2 O 8Z. Fig. 4 shows the hydrogen nuclear magnetic resonance spectrum of ethylene glycol monoethyl ether soyate. Table 2 presents the FTIR data along with their interpretations for ethylene glycol monoethyl ether soyate. Based on relevant literature, as analyzed in Figures 3 and 4, the peak corresponding to the fatty acid hydrocarbon group (R), with a mass ratio of 5.34 mg/kg, has an area value of 1.28. 8—4.23 mg/kg corresponds to the protons on C; it couples with the protons on C and splits into a triplet, with an area of 0. 89, corresponding to 2 hydrogen atoms ； 6=3.63 mg/kg corresponds to the protons on C, which are related to c. The proton coupling splitting on it yields three peaks, with an area of 0.82, corresponding to 2 hydrogen atoms ； 6—3.53 rag/kg is C. Protonated; it splits into a quartet due to coupling with the proton on C, with an area of 0.82, corresponding to 2 hydrogen atoms ； 8=：： 2.04 rag/kg corresponds to the protons on C, and it is related to c. Proton-coupled fission yields a triplet with an area of 1.56. The corresponding number of hydrogen atoms is 3. The other peaks with chemical shifts below 3.00 mg/kg are those corresponding to R-saturated C atoms bonded to protons. Based on the above analysis, it can be determined that the chemical structure of the product is RCO0C H. C. H OC H2C H3. } One f } 1., 1111 Ban WeiPu Information http://www.cqvip.com Issue 1: Zhang Hongyun et al.: Preparation of novel biodiesel. 2.4 Emissions tests for smoke from novel biodiesel. Figures 5 and 6 show the smoke emission characteristics at 1,800 r/min and 2,300 r/min. In the figure, a is the extinction coefficient, and BMEl is the average effective pressure. B. . Denotes biodiesel containing 5O, B. . Refers to pure bio-diesel. After burning the new type of biodiesel, the smoke density decreased by 59.8–78.8 at 1,800 r/rain, and by 2.9–83.3 at 2,300 r/rain. There are mainly two reasons for this: ① Biological diesel does not contain aromatic hydrocarbons; instead, it has a high content of saturated alkanes. Figure 5 shows the smoke emission characteristics at 1,800 revolutions per minute. 1.5 1.2 0.9 0.6 0.3 0 0.1 0 20. 3 0 4 0.5 0.6 0 7 BM EP/(M Pa) Storage 6 2 300 r/rain Emission characteristics of smoke Fig. 6 Smoke emission characteristics at 2,300 r/min. The carbon-to-hydrogen ratio (C/H) of aromatic hydrocarbons is much higher than that of alkanes; therefore, the smoke emission from bio-diesel is lower than that of pure diesel ； ② Biodiesel is an oxygen-containing fuel (with an oxygen content of over 10%). Oxygen atoms play a role in facilitating combustion; especially in areas where the fuel concentration is high, the reduction in oxygen content in the fuel prevents incomplete combustion, allowing the fuel to burn more completely and thus reducing smoke emissions. Through experiments, ethyleneglycol ether soybean oil monoester biodiesel results in significantly lower carbon smoke emissions compared to conventional biodiesel; therefore, this new type of biodiesel is an environment-friendly, oxygen-containing clean fuel. 3 Conclusions 3. l The optimal synthesis conditions for the new type of biodiesel are ； The molar ratio of ethylene glycol ethyl ether to oil is 6:1; the amount of catalyst used is 0.5% of the mass of soybean oil. The reaction temperature is 90°C, and the reaction time is 30 minutes. 3.2 The synthesis process of novel biodiesel is simple and easy to operate; the transesterification temperature is low, making the reaction easy to carry out. The raw materials are readily available, and the yield of the product is high. 3. 3 Burning new types of biodiesel can **reduce soot emissions by up to 83.3%.