异辛酸钒的合成研究与应用

本文研究了异辛酸钒的合成，得出了合成异辛酸钒的最佳工艺条件，并比较了异辛酸钒和环烷酸钴对聚酯树脂固化的促进效果。实验结果表明，采用该工艺，可保证产品的质量，使钒的转化率达到９９．９％以上，异辛酸钒的收率达到９８．０％以上，与环烷酸钴相比，异辛酸钒促进剂具有使用数量减少，颜色浅，气味轻，粘度小等特点。     

镧系盐催化合成辣椒酯衍生物研究

对比研究了三氯化铕,三氯化镧,三氯化铈和三氯化镨四种镧系盐催化剂化学选择酯化香草醇收率的影响。以三氯化镧为化学选择催化剂,且香草醇与三氯化镧物质的量比为1：0.005时,癸酸香草醇酯的收率最高为85%,并用该法合成辛酸香草醇酯和月桂酸香草醇酯,其收率分别为87%和71%。     

乙醇/柴油混合燃料的相溶性及对发动机性能影响的研究

利用助溶剂解决乙醇/柴油的相溶性问题,讨论了混合燃料中乙醇和助溶剂添加量对相溶性的影响,并使用助溶剂体积分数为1.5%、乙醇体积分数分别为5%、10%、15%的混合燃料及 20号纯柴油（分别表示为E5、E10、E15和 E0）在发动机台架上进行了性能和排放试验。研究结果表明,柴油的烃组成是决定相分离温度的决定性因素;对全部测试油品,乙醇体积分数在10%、助溶剂添加体积分数为1.5%时,混合燃料相溶性较好。台架试验显示,随着混合燃料中乙醇掺烧比例的增加,发动机的燃油消耗率逐渐增加,而发动机的额定功率和最大扭矩逐渐降低,但最大扭矩降低的幅度较小;此外,随着乙醇掺烧比例的增加,CO比排放量减少,HC、NOx和PM的比排放量逐渐增加,但NOx和PM的比排放量增加幅度不大。10%体积分数的乙醇添加量是乙醇/柴油的最佳掺烧比。     

纳米铁微粒的制备、表征及在煤油中的应用

由FeSO4·7H2O和NaBH4合成了纳米铁微粒,并用异辛酸进行表面包覆. 采用X射线衍射能谱(XRD)、透射电子显微镜(TEM)、氧弹量热计和热分析测试技术表征了纳米铁微粒的结构、形貌及热性能. 结果表明,制备的纳米铁微粒是体心立方晶系,颗粒呈球形,平均粒径100 nm,颗粒间呈粘连状. 热性能研究表明,在25～600 ℃范围内,异辛酸修饰前后,产物的总增质量由22%提高至28%,表明异辛酸的修饰提高了纳米铁的抗氧化性能;异辛酸修饰的纳米铁粉的添加量对煤油燃烧热值影响的研究结果表明,纳米铁粉加入到煤油中且质量百分数小于1%时,可使煤油的燃烧热值提高最大234.08 J/g.     

满足欧V排放标准的汽油车中偶催化剂

制备了具有高性能的稀土储氧材料Ce0.65Zr0.25Y0.07La0.03O1.95和镧稳定的氧化铝(La-Al2O3),并以此为基础制备了Pt-Pd-Rh型中偶汽油车尾气净化催化剂.老化前后的性能检测表明,稀土储氧材料具有较大的比表面积和优异的储氧性能,La-Al2O3也具有优越的织构性能和高的热稳定性.催化剂对模拟尾气具有较高的催化活性和稳定性,在捷达-MT型汽油车上的测试结果表明,经该催化剂处理后的尾气排放能够满足欧Ⅴ排放标准.     

市场动态

燃油添加剂用上纳米技术 北京大学李正孝教授率先应用纳米技术开发出一种纳米燃油添加剂,这种产品不仅可以大大降低机动车尾气中氮氧化物等污染物的排放,还可(?)油10％～20％。国家环保总局机动车排污监控中心出具的检测数据表明:添加纳米燃油添加剂后,碳氢化合物、一氧化碳和氮氧化物的排放量分别降低14.3％、7.8％和13.8％。     

稀土复合型柴油催化助燃剂的研制及应用

采用铈、铂的有机配合物及碳酸酯制备出一种稀土复合型柴油催化助燃剂.通过发动机台架试验,表明添加剂可有效降低碳烟PM和NOz排放,并且发动机热效率有所提高.     

柠檬酸镧的合成及其对SBR橡胶硫化性能的影响

以氯化镧和柠檬酸为原料,合成柠檬酸镧,探究反应条件对柠檬酸镧产率的影响,得到反应体系p H值4~5之间,柠檬酸与氯化镧的摩尔比1.2∶1,反应体系温度50℃为较优的反应条件。并将合成的柠檬酸镧添加到SBR混炼胶中,研究其对混炼胶的硫化特性和硫化胶物理机械性能的影响;结果表明,添加2.5%的柠檬酸镧可使混炼胶的硫化速率t90达到943 s,比未添加柠檬酸镧的快了31 s,当添加量为7.5%时硫化胶的物理机械性能达到最佳,比未添加相比提高了将近50%。通过红外光谱表征产物结构,并采用硫化仪、万能试验机对混炼胶进行硫化性能及物理机械性能测试,研究结果表明,柠檬酸镧可提高混炼胶的硫化性能、硫化胶物理机械性能及抗硫化还原性。因此,柠檬酸镧可以作为SBR橡胶硫化剂的一种补充。     

镧系盐催化合成辣椒酯衍生物

对比研究了三氯化铕、三氯化镧、三氯化铈和三氯化镨4种镧系盐催化剂化学选择酯化香草醇收率的影响. 结果表明,三氯化镧为最佳催化剂,当n(香草醇)∶ n(酰氯)∶ n(三氯化镧)=1∶ 1∶ 0.005时,辛酸香草醇酯、癸酸香草醇酯及月桂酸香草醇酯的收率可分别达87%、85%和71%.     

车用尿素液的测定方法

<正>国家环保部《关于实施国家第四阶段车用压燃式发动机与汽车污染物排放标准的公告》规定所有生产、进口、销售和注册登记的车用压燃式发动机与汽车必须符合国四标准的要求。"所谓车用压燃式发动机与汽车,主要是指柴油发动机和柴油车。据经济之声报道,大货车尾气排放污染,是严重影响PM2.5指标参数的重要因素。据环保部的数据,2011年我国的柴油车仅占机动车总保有量的6.3%,而氮氧化物排放量     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.