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食品包装材料上油墨中残留烷基苯成分分析及其迁移性的GC-MS研究 总被引:6,自引:0,他引:6
建立了一种食品包装材料上多色油墨中残留烷基苯成分的提取和气相色谱-质谱联用(GC-MS)分析方法. 采用选择离子检测(SIM)模式, 以内标定量法对某些食品包装材料上多色油墨中烷基苯残留量进行了准确定量分析. 对油墨中残留烷基苯向食品中迁移的初步研究结果表明, 包装材料上油墨中的苯及苯系物等有害物质可能透过薄膜进入食品而造成污染. 相似文献
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FCC催化剂氢气还原活化脱镍研究 总被引:1,自引:0,他引:1
我国的FCC催化剂在使用中镍污染较为严重, 镍不仅会破坏催化剂的结构, 而且还会影响反应产物的分布, 增加企业的生产成本. 本研究提出了氢气还原活化+稀硝酸洗涤的脱镍新方法, 具有良好的效果. 镍在FCC催化剂上以NiAl2O4和Ni2SiO4的形式存在, 这些物种在700 ℃以下就可以被氢气还原, 并且随着温度的升高, 不仅催化剂表面的镍能够被还原, 而且催化剂体相中的镍也可以迁移到表面从而被还原, 但这种迁移受到平衡的限制. 还原后生成的金属镍可以溶于稀硝酸, 因而可以洗涤除去. 在适宜的条件下, 经过一次还原+酸洗处理, 脱镍率可达到50%以上; 经过两次处理, 脱镍率可达75%以上. 脱镍后催化剂的微反活性可以得到大幅度提高. 相似文献
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蓝藻水华衍生的微囊藻毒素污染及其对水生生物的生态毒理学研究 总被引:2,自引:0,他引:2
富营养化导致的蓝藻水华频发,引发各种衍生物污染,严重时造成重大生态灾害事件,甚至危及人类健康。其中微囊藻毒素以其毒性大、分布广和结构稳定的特点,成为水环境中常见的潜在危害物质,它主要由微囊藻产生,是一类具有多种异构体的环状七肽物质。本文根据微囊藻毒素污染现状及其水生生态毒理学研究的最新研究进展,介绍了微囊藻毒素的理化性质及其产生、迁移和转化,在我国天然水体、水库源水和饮用水中的污染现状以及部分水产品中的微囊藻毒素累积情况,较全面地评述了微囊藻毒素的分子致毒机理以及对水生生态系统的重要组成成分--常见水生植物和鱼类的生态毒理学效应,并提出了该领域未来研究的主要方向。 相似文献
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《中国稀土学报》2016,(3)
赣南离子型稀土浸矿开采过程中,因大量使用(NH_4)_2SO_4作浸矿剂造成土壤氮化物累积,引发矿区土壤及水体氮化物的持续严重污染。通过模拟土柱实验,测定原矿土壤(未开采的稀土矿土壤)和一般土壤(矿山周边的普通土壤)在模拟浸矿过程中氮化物的污染含量,研究氮化物在土柱实验中的迁移特征及规律。结果表明:浸矿过程中,原矿土壤和一般土壤中氮化物主要以铵态氮形式存在,说明铵态氮是导致稀土矿区土壤污染和水环境污染的主要原因;同时由于土壤的固氮作用、淋滤过程中铵态氮向下迁移及减少的共同作用,致使试验中原矿土壤和一般土壤铵态氮含量总体随天数表现为降低、升高、再降低趋势;并且与一般土壤相比,原矿土壤中稀土离子和NH~+_4会发生交换解析作用增加原矿土壤的固氮作用,同时稀土的存在会增加土壤本身对氮化物的吸附能力。研究结论为赣南离子型稀土矿浸矿过程中氮化物的迁移规律提供基础依据。 相似文献
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电解质迁移热力学性质的测定,对于离子溶剂化的研究具有重要意义.迁移自由能主要反映离子与溶剂分子间的相互作用,迁移熵则主要反映不同溶剂分子间的相互作用,迁移熵随温度及溶剂组成的改变可为溶剂的原有结构推测及溶液秩序改变提供信息.我们曾运用离子选择性电极测定了部分碱金属卤化物在水及含水混合溶剂中的热力学性质[1-3].本文用离子选择性电极方法,通过测定不同温度下电池的标准电动势,根据溶液热力学原理,求得RbCl由H2O至混合溶剂(H2ODMF)的标准迁移自由能ΔGt及其温度系数,计算RbCl的标准迁移熵ΔSt.结果尚未见… 相似文献
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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%. 相似文献
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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. 相似文献
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Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction
Laurent Gavara Thomas Boisse Jean-Pierre Hénichart Adam Daïch Philippe Gautret 《Tetrahedron》2010,66(38):7544-5571
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. 相似文献
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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. 相似文献
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Rebecca J. Burton Mandy L. CrowtherNeal J. Fazakerley Shaun M. FilleryBarry M. Hayter Jason G. KettleCaroline A. McMillan Paula PerkinsPeter Robins Peter M. SmithEmma J. Williams Gail L. Wrigley 《Tetrahedron letters》2013
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. 相似文献
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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. 相似文献
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N. A. Nedolya 《Chemistry of Heterocyclic Compounds》2008,44(10):1165-1219
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. 相似文献
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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. 相似文献
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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. 相似文献
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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. 相似文献