Synthesis of Polyoxymethylene Dimethyl Ethers Catalyzed by Pyrrolidinonium‐Based Ionic Liquids

Polyoxymethylene dimethyl ethers (PODE_n) are widely applied as diesel additives in engines. Ionic liquids (ILs) replace traditional liquid acids as catalysts in chemical processes. A series of pyrrolidinonium‐based Brønsted acidity ILs were synthesized, investigated, and employed as catalysts for the synthesis of PODE_n from methylal and trioxane for the first time. The Hammett function values were measured to uncover the connection between catalytic performance and acidity‐activity of the ILs considered. The optimal experimental conditions for the synthesis of PODE_n were determined. The maximum values of both the conversion of raw material and the selectivity of PODE_3–8 were obtained with 1‐octyl‐2‐pyrrolidinonium trifluoromethanesulfonate ([NOP][TFO]) as the catalyst. [NOP][TFO] provides greater selectivity of PODE_3–4 than the traditional catalysts such as H₂SO₄ and CF₃SO₃H.     

Formation kinetics of polyoxymethylene dimethyl ethers from methylal and trioxane with little water

Polyoxymethylene dimethyl ethers(CH_3-O-(CH_2 O)n-CH_3, PODE_n, n1) can be added to diesel to reduce air pollution caused by incomplete combustion. Driven by this need, a cost-effective and efficient synthetic route is presented and investigated by this work for the production of PODEn, which are formed from methylal and trioxane with low water content(10 %(mass)) over HZSM-5 catalyst in a batch slurry autoclave at the temperature from 353.15 K to 393.15 K. The reaction rate laws including the PODEnand byproducts of polyoxymethylene hemiformals(HF_n), polyoxymethylene glycols(MG), methanol(Me OH) and methyl formate(MF) are developed. The rate constants of propagation step(k_6) and depolymerization step(k_(-6)) are assumed independent on polymerization degree of PODE_n. The rate of reaction is proportional to the content of the catalyst(W_(cat)) for the catalytic reaction within the scope of the study. All kinetic parameters were estimated by combining genetic algorithm and least square regression to fit experimental data well. This work is valuable for process optimization and reactor design.     

Controllable synthesis of polyoxymethylene dimethyl ethers by ionic liquids encapsulated in mesoporous SBA-16

The promising combustion and emission properties of polyoxymethylene dimethyl ethers(PODE_n) are of significant interest. However, the synthesis of PODE_n products with desired chain lengths is still a problem facing synthetic PODE_n. Herein, a series of unique IL@SBA-16-Cx solid catalysts are prepared by encapsulation of ionic liquids(ILs) within the nanocage of SBA-16 through a silylation method. The structure of the encapsulated catalyst was characterized by UV–vis spectra, Fourier transform infrared(FT-IR),N_2 adsorption–desorption isotherms, Powder X-ray diffraction(XRD), Transmission electron microscopy(TEM) and Elemental analysis. The encapsulated catalysts show similar catalytic activity to the homogeneous counterparts and display higher selectivity to the targeted PODE_(3–5) products than their homogeneous counterparts in the synthesis of PODE_n from methanol(MeOH) and trioxymethylene(TOM). The encapsulated catalysts exhibit a superior PODE_(3–5) selectivity and could be the promising catalysts for PODE_n synthetic reaction.     

柴油添加剂的国内外发展

柴油添加剂的使用可降低柴油中硫化物和碳氢化合物等有害物质含量,并提升燃油燃烧效率,节省燃油成本,提高了柴油的经济效益。这里主要介绍了柴油燃料中四大类添加剂目前在国内外的研究与应用状况,并对各类添加剂作用机理的研究现状作了一定的阐述,最后指出柴油添加剂的今后发展方向。     

抗静电剂在3^#喷气燃料中的应用

不同类型的抗静电剂在3#喷气燃料中的使用效果不相同。对T 1501、T 1502、Stadis 450 3种类型的抗静电剂在石炼化公司3#喷气燃料中的应用情况做了系统研究和分析。试验结果表明,抗静电剂型号不同、加剂量不同时,3#喷气燃料的电导率和水反应的质量情况不同,电导率的结果受测定温度的影响较大。找出了适合石炼化公司3#喷气燃料的抗静电剂品种和加剂量。     

国外清洁燃料生产技术进展

随着环境保护要求的不断提高，对汽车燃料的限制也越来越严格，主要体现在对燃料油中硫、烯烃、苯以及芳烃含量的限制，这就要求世界炼油业对现有的工艺不断进行改进、创新并开发一些先进技术来生产清洁燃料；因此生产清洁燃料是目前乃至今后相当长时间内炼油工业的发展趋势。本文介绍了燃料清洁化的进程清洁燃料生产的典型技术及其进展和新型燃料，包括加氢技术、吸附技术、选择性氧化脱硫技术、超声波技术、合成油技术等清洁燃料生产技术。     

阳离子交换树脂催化合成富马酸二甲酯

采用国产强酸性阳离子交换树酯 S- 54作催化剂 ,对以富马酸与甲醇为原料的酯化合成富马酸二甲酯的反应过程进行了研究。考察了原料配比、催化剂用量、酯化时间、反应温度等操作条件对富马酸二甲酯收率的影响 ,并运用正交实验法确定了反应的最佳工艺条件为 :醇酸摩尔比为 8∶1 ,;催化剂相对于富马酸的用量为 40 % ;酯化时间为 8h;反应在沸腾状态下进行 ,催化剂以颗粒状加入并辅以不断的搅拌 ,可加速反应的进行。     

MAV型柴油降凝剂的合成及效果的考察

以十六醇和丙烯酸为原料,n(十六醇):n(丙烯酸)=1.0:1.6,阻聚剂对苯二酚为0.6%(质量分数,下同),催化剂对甲苯磺酸为1.5%,合成丙烯酸酯;再用此丙烯酸酯与马来酸酐、醋酸乙烯酯进行共聚,n(马来酸酐):n(醋酸乙烯酯):n(丙烯酸酯)=1:4:4,过氧化苯甲酰为1.2%,恒温85℃,聚合7 h.即得MAV型柴油降凝剂.以不同的添加量,分别加入到抚顺石油一厂0#、二厂0#、三厂0#、一厂-10#和三厂-10#柴油中,考察其降凝助滤效果.结果表明:最佳添加量为0.6%,此时可使上述柴油的凝点分别降低12、12、13、15和16℃,冷滤点分别降低6、6、8、8和9℃.可见其降凝助滤效果是非常显著的.     

新型二乙胺阴离子交换树脂制备方法的研究

通过Friedel-Crafts反应在交联聚苯乙烯微球上进行氯乙酰化反应引入氯乙酰基,再经胺化得到弱碱性叔胺型阴离子交换树脂.该方法避免了使用氯甲醚等致癌物质,也避免了二次交联及多取代等副反应.今讨论了不同溶剂对胺化反应的影响,并用数学软件Statistica 6.0对反应时间、反应温度、试剂用量等条件进行了优化,得到的最佳条件为:溶剂量5 mL·g-1,温度70℃,二乙胺与氯乙酰基摩尔比12:1,反应时间2 h.担载量可达3.5 mmol·g-1树脂.     

ZSM-5分子筛固定床催化合成聚甲氧基二甲醚

通过X射线衍射（XRD）、扫描电子显微镜（SEM）、氨气程序升温脱附（NH₃-TPD）和吡啶吸附-红外光谱（Py-IR）等对不同硅铝比（SiO₂/Al₂O₃）的ZSM-5分子筛粉末催化剂进行表征。在间歇反应器中,本文对比了不同硅铝比ZSM-5分子筛粉末催化三聚甲醛和甲缩醛合成聚甲氧基二甲醚（PODE）的催化活性,结果表明硅铝比为400的ZSM-5分子筛粉末具有最高的PODE_2~8的收率和选择性。然后,采用挤条成型法,在ZSM-5分子筛粉末（SiO₂/Al₂O₃=400）中加入硅溶胶黏结剂和甲基纤维素黏结剂,制备得到ZSM-5成型催化剂,硅溶胶添加量和甲基纤维素分子量影响成型催化剂强度。采用ZSM-5成型催化剂,以固定床为反应器,反应温度和反应空速在所考察的范围内对三聚甲醛（TOX）的转化率和PODE的选择性影响较小。在85℃、压力1MPa、空速为5h^-1的条件下进行了240h催化性能考察,成型催化剂催化性能稳定,三聚甲醛的转化率高于90%,PODE_2~8的选择性达到95%以上。     

Modeling of the Adsorptive Desulfurization of Diesel Fuel in a Fixed‐Bed Column

Adsorptive desulfurization enables the attainment of ultra‐low sulfur content in hydrocarbon fuels by removing the refractory sulfur compounds, which are difficult to remove in hydrodesulferization (HDS) processing when sulfur concentrations below 10 mg kg^–1 must be attained. In this work, diesel fuel was desulfurized by adsorption using activated carbon as an adsorbent and the adsorption was carried out in a fixed‐bed column. The output sulfur content of less then 0.7 mg kg^–1 was achieved for the lowest flow rate of 1.0 cm³min^–1 and the highest bed depth of 28.4 cm at 50 °C. In all the experiments, at least one output sample contained less then 10.0 mg kg^–1 of sulfur with a longest achieved breakthrough time of 11.8 h. A mathematical model of the fixed‐bed adsorber was applied to describe the kinetics and to estimate the breakthrough curves. The model equations included a differential material balance for a liquid phase and a mass transfer rate expression. The ability of the model to fit the experimental data was shown to be satisfactory.     

煤基甲醇制清洁柴油添加剂聚氧醚的研究

开发了以固体酸性材料分子筛或固体超强酸为催化剂,由甲醇与三聚甲醛或多聚甲醛为原料合成聚氧醚的工艺。通过对催化剂种类、酸性、比表面、原料配比、反应分压考察发现,以固体超强酸Z5为催化剂、403 K、自生压力、醇醛摩尔比2.2时,能够获得最高的原料转化率和聚氧醚产物收率。研究表明,所用固体超强酸较小的比表面积使得催化剂上的酸性位较少,限制了催化剂的活性。     

Synthesis and Performance of a Multi-Purpose Gemini Precursor and the Derivative Alkylaryl Sulfonate Gemini Surfactants

The phenol–formaldehyde condensation reaction to synthesize a gemini precursor was renewed by using high efficient and environmentally benign resin catalysts instead of protonic acids, and the conversion, yield and selectivity of the reaction were all upgraded from the 60 % by the traditional way to over 90 % by the new way. Three alkylaryl sulfonate gemini surfactants were derived from the above gemini precursor by O-methylation, sulfonation and neutralization, that is, sodium salt of sulfonated bis(2-hydroxy-5-nonylphenyl)methane (SBHNM), sodium salt of sulfonated bis(2-hydroxy-5-dodecylphenyl)methane (SBHDM) and sodium salt of sulfonated bis(2-methoxy-5-nonylphenyl)methane (SBMNM). And their performances in aqueous solution were further investigated. The results show that the three gemini surfactants exhibit higher effectiveness and efficiency in surface tension reduction than a monomeric reference surfactant sodium dodecylbenzene sulfonate (SDBS). Furthermore their critical micelle concentration values are at least one order of magnitude lower than that of SDBS. It is also shown that O-methylation of the hydroxyl group in the gemini precursor is effective at improving the surface activity of the gemini surfactants, such as efficiency in surface tension reduction, foam stability and calcium stability. It is suggested that the synthesized hydrophobic skeleton could be a multi-purpose gemini precursor from which various gemini surfactants could be derived by further hydrophobic or hydrophilic modification.     

Synthesis of alkyloxy (di)alkylamino propanols, hydroxy alkyloxy (di)alkylamino propanols, and the dimer compounds for use as fuel additives

Alkyl glycidyl ethers and bis glycidyl ethers, synthesized in a heterogeneous weakly hydrous medium, were condensed with primary or secondary amines to obtain 3-alkyloxy propanolamines or bis alkyloxy propanolamines in a regioselective manner. The compounds were characterized by conventional spectroscopic methods, and complete nuclear magnetic resonance data are given. Their high-temperature stability, their good emulsifying power, their oxidation, and corrosion inhibition make these compounds suitable for solubilizing ethanol-diesel fuel blends.     

Synthesis and Characterization of a New Fluorine‐Containing Polybenzimidazole (PBI) for Proton‐Conducting Membranes in Fuel Cells

A new type of fluorine‐containing polybenzimidazole, namely poly(2,2′‐(2,2′‐bis(trifluoromethyl)‐4,4′‐biphenylene)‐5,5′‐bibenzimidazole) (BTBP‐PBI), was developed as a candidate for proton‐conducting membranes in fuel cells. Polymerization conditions were experimentally investigated to achieve high molecular weight polymers with an inherent viscosity (IV) up to 1.60 dl g^–1. The introduction of the highly twisted 2,2′‐disubstituted biphenyl moiety into the polymer backbone suppressed the polymer chain packing efficiency and improved polymer solubility in certain polar organic solvents. The polymer also exhibited excellent thermal and oxidative stability. Phosphoric acid (PA)‐doped BTBP‐PBI membranes were prepared by the conventional acid imbibing procedure and their corresponding properties such as mechanical properties and proton conductivity were carefully studied. The maximum membrane proton conductivity was approximately 0.02 S cm^–1 at 180 °C with a PA doping level of 7.08 PA/RU. The fuel cell performance of BTBP‐PBI membranes was also evaluated in membrane electrode assemblies (MEA) in single cells at elevated temperatures. The testing results showed reliable performance at 180 °C and confirmed the material as a candidate for high‐temperature polymer electrolyte membrane fuel cell (PEMFC) applications.