微波辅助组合离子液体直接制备微藻生物柴油

采用小球藻、甲醇为原料,离子液体组合物作为提取催化剂,微波辅助原位一步法催化制备微藻生物柴油。考察微波功率、离子液体类型、离子液体用量、反应温度、反应时间、醇油物质的量之比等因素对酯交换率的影响,并与传统水浴加热机械搅拌法比较。结果表明:微波和离子液体对生物柴油的制备有协同促进作用,离子液体具有催化、提取与增溶的作用,能较好地消除醇油界面接触,微波的引入可强化传质传热过程,与传统加热方式水浴加热机械搅拌法相比,可缩短酯交换反应的时间,降低反应温度,减少离子液体、甲醇用量。离子液体[BMIM][HCOO]为提取剂,微藻油脂提取率最高;酸性离子液体催化效果明显高于碱性离子液体,离子液体[SO₃H-BMIM][HSO₄]为催化剂,微藻油脂转化率最高。在甲醇用量和藻粉质量比为6∶1,离子液体组合物和藻粉质量比为5∶1,[BMIM][HCOO]与[SO₃H-BMIM][HSO₄]体积比12∶1,微波功率400 W,反应温度为60℃,反应时间40 min条件下,生物柴油转化率可达93.3%。该方法将离子液体溶解提取性能、催化性能及微波的热效应相结合,将油脂的提取与油脂的酯化合二为一,能够实现微藻生物柴油的一步转化制备。     

微藻直接离子液体脂肪酶制备生物柴油

采用小球藻、甲醇为原料,脂肪酶为催化剂,离子液体为提取剂和反应介质,直接提取酯交换制备生物柴油。考察不同工艺条件对产率的影响,结果表明:甲醇用量和藻粉质量比为8∶1,离子液体[BMIM][DCA]和藻粉质量比为1∶1,脂肪酶用量为藻粉质量的12%,反应温度为50℃,酯交换反应时间为16 h条件下,生物柴油的转化率可达69.6%。采用微藻直接离子液体脂肪酶制备生物柴油无需从微藻粉中提取油脂,因此降低过程成本、缩短工艺,能实现含油微藻到生物柴油的一步转化。     

生物柴油制备新工艺的研究进展

综述了生物柴油的特性及其生产方法,介绍了酯交换法制备生物柴油的反应机理及其近年来出现的各种新生产工艺,包括超临界法、生物催化法、超声波法、离子液体法等,指出了生物柴油技术发展面临的问题及研究方向。     

生物炭基材料在生物柴油制备中的研究进展

不同种类的生物质原料可通过热转化的方式制备生物炭,由于其独特的特性被广泛应用于不同的研究领域。近期,随着生物炭合成方法的大规模涌现,生物炭及生物炭基材料相关的研究广受关注。总结了生物炭基催化剂在生物柴油制备（酯交换/酯化反应）过程中的研究现状,简要描述了生物炭催化剂的设计和合成方法,并总结了生物炭催化剂在制备生物柴油中的应用,最后归纳了生物炭基催化剂在生物柴油制备中存在的问题,对今后的研究重点及前景做出展望,以期为将来低成本生物炭基催化剂的制备以及生物柴油合成的研究和发展提供指导建议。     

地沟油制备生物柴油过程中硫化物迁移及脱除研究

采用地沟油等餐饮废弃油脂转化制备生物柴油中会含有一定量的硫化物,针对上述问题,考察传统的酸碱两步法制备生物柴油过程中硫化物的迁移,并以离子液体（[Hnmp]H₂PO₄）为萃取剂和催化剂,H₂O₂为氧化剂,对粗生物柴油进行萃取氧化脱硫,并利用正交实验法对萃取氧化脱硫反应工艺进行优化。结果表明：反应过程使用的试剂和操作条件几乎不会增大生物柴油制备过程中的硫含量以及改变硫化物在反应体系中的存在形态,硫化物含量及存在形式与原料油自身所含硫化物形态有关。S元素在地沟油原料及生物柴油粗成品中的存在形式主要以噻吩、硫醇、硫醚、硫胺素、硫代葡萄糖苷等物质为主,其中噻吩类硫化物约占地沟油原料或生物柴油中总含硫质量分数的93%以上。在粗生物柴油与离子液体体积比为10∶3,粗生物柴油与H₂O₂体积比为10∶1.2,反应温度75 ℃,反应时间70 min条件下,生物柴油脱硫率达94%以上,脱硫后的生物柴油满足最新国Ⅵ柴油排放标准（GB 17930—2016）硫含量≤10 mg/kg要求。     

Brønsted酸性离子液体合成及催化制备生物柴油

合成4种成功能化酸性离子液体,采用红外光谱、热重分析等分析法进行表征验证,并用其催化菜籽油酯交换制备生物柴油,考察醇/油物质的量之比、反应温度、反应时间、离子液体用量和水含量对转化率的影响。结果表明,4种离子液体都有较强酸性,与浓硫酸酸性相当;带—SO₃H基团的离子液体表现出更好的催化活性,且随着烷基链的增加,催化活性提高;在（n甲醇）∶n（菜籽油）=12∶1,反应温度130 ℃,反应时间3 h,离子液体（[BSO₃HMIM][HSO₄]）用量为菜籽油质量2%（质量分数）条件下,生物柴油转化率可达99%以上。在反应体系中,水会破坏离子液体的结构并导致其失活,而升高反应温度,可缓解水对离子液体的结构破坏,在130 ℃条件下,即使水分含量为5%时,生物柴油转化率仍可保持在约85%。     

制备生物柴油所用催化剂的研究进展

生物柴油作为一种清洁的可再生能源,可以由动植物油脂通过酯交换反应来制备.本文概述了近年来制备生物柴油的多种催化剂,并探讨了各自的优点及缺陷.     

增溶易分离离子液体均相催化剂合成及催化制备生物柴油工艺研究

以离子液体和磷钨酸为原料,制得3种功能化磷钨酸盐离子液体,采用红外光谱、热重分析等进行表征验证,并用其催化棕榈油酯交换制备生物柴油,考察醇油物质的量之比、反应温度、反应时间和离子液体用量对反应的影响及离子液体的稳定性。结果表明:所制备的磷钨酸盐离子液体具有较好的温控相转移和酸催化性能,能实现高温反应和低温分离效果,与纯H₂PW₁₂O₄₀、固定化H₂PW₁₂O₄₀、[MIMPS]H_SO₄传统催化剂相比,表现出更好的溶解、催化和回收性能,在n(甲醇)∶n(棕榈油)=10∶1,反应温度120℃,反应时间8 h,1-丙基磺酸-3-甲基咪唑磷钨酸盐离子液体([MIMPS]H₂PW₁₂O₄₀)质量为棕榈油7%的条件下,生物柴油收率可达95.6%,且该离子液体稳定性良好,循环使用5次催化性能无明显降低。     

磺酸型离子液体合成及催化制备生物柴油工艺研究

研究合成功能化酸性离子液体1-丙基磺酸-3-甲基咪唑硫酸氢盐([PrSO_3HMIm]HSO_4),采用核磁共振、红外光谱、热重分析等分析法进行表征验证,并用其催化菜籽油酯交换反应制备生物柴油,考察醇油物质的量之比、反应温度、反应时间和离子液体用量对酯交换反应的影响及离子液体的稳定性。结果表明:在n甲醇∶n菜籽油=10∶1,反应温度120℃,反应时间8 h,离子液体用量为菜籽油质量7%的条件下,生物柴油收率可达95.56%,且稳定性良好,循环使用5次催化性能未明显降低。     

一种新型菜籽油酯生物柴油的制备

以精制菜籽油、乙二醇单甲醚为原料,以KOH为催化剂,制备出一种含氧量更高的新型生物柴油.采用正交试验研究了反应物配比、催化剂用量、温度、反应时间等因素对产物产率的影响,得出了最佳合成条件,并运用红外光谱与核磁共振法分析了产物的结构.柴油机台架试验表明,燃烧该新型生物柴油后,废气排放大幅度降低.     

Catalytic performance of a novel amphiphilic alkaline ionic liquid for biodiesel production: Influence of basicity and conductivity

Three novel alkaline guanidine ionic liquids as amphiphilic catalysts have been successfully synthesized for two-phase transesterification, which can efficiently improve the catalytic activity for the synthesis of biodiesel. They were characterized by a series of techniques including ¹H NMR, thermal stability, electronegativity (DFT calculation), basicity and conductivity. It was demonstrated that 1,1,3,3-trimethyl-2-octyl-guanidine hydroxide(IL3) exhibited better catalytic activity compared with other base guanidine ionic liquid catalysts, which was related to the better basicity and electronegativity of the ILs. The experimental results indicated that catalytic performance was relative to both enough alkaline center and conductivity of ionic liquid catalysts, but the former was a main factor in the catalytic system. The catalytic performance also revealed that optimum catalyst dosage was about 6 wt.%, the appropriate reaction temperature was about 55 °C, the optimum n(Methanol)/n(Soybean Oil) for the biodiesel synthesis was about 15:1 and the suitable reaction time was 4 h on the basis of biodiesel yield of 97%. In addition, the reaction mechanism of the amphiphilic catalyst was illuminated by the interaction between the methoxyl group and the carbonyl group of the triglyceride after activating for two-phase transesterification.     

An overview of ionic liquids as solvents in biodiesel synthesis

Transesterification is the most common method for producing biodiesel. Known as a suitable substitute to diesel fuel, the synthesis involves renewable sources as feedstock. Application of both organic and inorganic solvents in biodiesel production has been widely established. However, as the properties of conventional solvents are perpetually hazardous to human and environment, utilization of greener alternative is a better option. Among the various types of solvents available, ionic liquid seems prevalent. An ionic liquid is a combination of cations and anions, has low or negligible vapor pressure, and exists as liquid at temperature below 100 °C. The prospect of ionic liquids as green solvents in chemical processes is increasing in recent years, especially in biodiesel synthesis. This paper highlighted the properties of ionic liquids that emphasized their versatility as solvents, and the use of switchable ionic liquids as green solvents is also presented. The roles of ionic liquids in biodiesel synthesis are discussed, focusing on their pertinent capability as solvents, particularly as catalysts for transesterification reaction. Since the cost of ionic liquid may be an issue, a brief discussion about the recyclability of ionic liquids is also included.     

固定化脂肪酶在离子液体中催化合成生物柴油

通过硅胶载体涂布法对细菌Burkholderia cepacia GX-35所产的脂肪酶进行固定化。比较了自制固定化脂肪酶在4种离子液体中催化合成生物柴油的效果,其中文章研究新设计并合成的一种离子液体溴代1-乙基-2-甲基咪唑[EMIM]Br对催化反应起促进作用。通过对转酯率的测定,研究了固定化脂肪酶在[EMIM]Br中的最适反应条件:最适反应温度为35℃,[EMIM]Br加入量为花生油质量分数的60%,最佳醇类为乙醇,加水量为花生油质量分数的5%,乙醇与花生油之比为9∶1,固定化脂肪酶加入量为花生油的20%,反应时间为6 h。固定化脂肪酶在[EMIM]Br中稳定性好,使用6次之后转酯率下降不明显。试验结果表明,与不加[EMIM]Br相比,加[EMIM]Br能有效提高生物柴油的转化率。     

Ionic liquid microemulsion mediated synthesis of Pt/TiO2 nanocomposites for ammonia borane hydrolysis

Tunable microstructure of microemulsion self-assembly systems has the prominent application as nanoreactors in reaction processes. Scientific and technological interest in microemulsions derived from the confinement effect of polar or nonpolar domains for hydrophilic/hydrophobic molecules. Benefiting from the tunable nature, ionic liquids-based self-assembly systems have been demonstrated as a versatile platform for catalytic reaction, drug delivery, functional materials fabrication and among others. In this work, ionic liquids microemulsions were designed by using ionic liquids as apolar phase and surfactant. The phase equilibrium and microstructure were studied through phase diagram, conductivity method and dynamic light scattering. Ionic liquids-in-water microemulsions were proposed as nanoreactor for fabrication of nanosized platinum/titanium dioxide composites. The size, morphology and catalytic performance can be tuned by the microemulsion structure through its confinement effect. The hydrolysis of ammonia borane catalyzed by these composites exhibits better catalytic activity with higher turnover frequency and lower activation energy of the reaction. It is believed that the nanoreactors constructed from versatile ionic liquids will provide new guidance in designing advanced scientific applications.     

New horizons in the enzymatic production of biodiesel using neoteric solvents

Globally, tougher legislation in greenhouse gases emissions is prompting the hunt for more sustainable and competitive strategies to synthesize biodiesel. Although enzyme-catalyzed processes are considered as a more environmentally-friendly option, there are still challenges to be approached like the replacement of traditional solvents due to their well-known disadvantages such as their volatility, toxicity or carcinogenic character. Thus, the emergence of neoteric solvents such as perfluorocarbons, liquid polymers, ionic liquids, deep eutectic solvents or supercritical fluids has opened up new opportunities to reach truly green processes. Nonetheless, literature analysis reveals the scarcity of research works, which are exclusively restricted to the last three types of solvents. One of the critical points to take into account refers to the performance of enzymes in this kind of milieu, as this environment may be deleterious in terms of protein structure, leading to enzyme deactivation. Therefore, the final purpose of this review paper is to identify the current trends of research in the field of neoteric solvents applied to enzyme-catalyzed synthesis of biodiesel and to shed light on the possible existing gaps.     

Hydrogen storage in amine boranes: Ionic liquid supported thermal dehydrogenation of ethylene diamine bisborane

A variety of ionic liquids has been tested for its catalytic effect on the dehydrogenation of ethylene diamine bisborane (EDB). The catalytic activity of ionic liquids, such as 1-butyl-2,3-dimethylimidazolium chloride ([BMMIM]Cl), 1-butyl-2,3-dimethylimidazolium acetate ([BMMIM][OAc]), 1-butyl-3-methylimidazolium acetate ([BMIM][OAc]) and 1-butyl-3-methylimidazolium methylsulfonate ([BMIM][OMs]) is compared and the mixture [BMMIM]Cl/EDB was investigated. This system is able to deliver about 6.5 wt% of hydrogen at 140 °C competing with conventional hydrogen storage pressure tanks. The correlation between polarity of the ILs and hydrogen yield was investigated and the suitability for hydrogen storage systems is evaluated and discussed.     

Reactions of lignin model compounds in ionic liquids

Lignin, a readily available form of biomass, is a potential source of renewable aromatic chemicals through catalytic conversion. Recent work has demonstrated that ionic liquids are excellent solvents for processing woody biomass and lignin. Seeking to exploit ionic liquids as media for depolymerization of lignin, we investigated reactions of lignin model compounds in these solvents. Using Brønsted acid catalysts in 1-ethyl-3-methylimidazolium triflate at moderate temperatures below 200 °C, we obtained up to 11.6% molar yield of the dealkylation product 2-methoxyphenol from the model compound 2-methoxy-4-(2-propenyl)phenol and cleaved 2-phenylethyl phenyl ether, a model for lignin ethers. Despite these successes, acid catalysis failed in dealkylation of the saturated-chain model compound 4-ethyl-2-methoxyphenol and did not produce monomeric products from organosolv lignin, demonstrating that further work is required to understand the complex chemistry of lignin depolymerization.     

固体酸催化剂在生物柴油合成实验中的研究

针对生物柴油催化合成技术中，采用一般催化剂所存在的问题，自制了4种固体酸催化剂，测试了它们在以大豆酸化油为原料制备生物柴油反应中的催化活性及重复使用性，确定了合成生物柴油的工艺条件。