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《理化检验(化学分册)》2016,(10)
正亚氨基二乙酸(IDA),又名氨二乙酸,是一种重要的精细化工中间体,广泛应用于农药、电镀、染料、络合剂、表面活性剂、水处理和电子等领域[1-2]。以氢氰酸为原料生产甘氨酸,在氨化过程中生成亚氨基二乙酸、氮川三乙酸等副产物。因此,准确地测定亚氨基二乙酸的含量,对于工艺操作控制、提高收率及产品质量有重要作用。亚氨基二乙酸的测定目前尚未有统一的国家标准,通常采用碱直接滴定法[3]、柱前衍生气相色谱 相似文献
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铽-亚氨基二乙酸-钛铁试剂休系,镝-氨羧络合剂-钛铁试剂体系已有研究报道。铽和镝是稀土元素中原子序数相邻的两个元素,两者共存,不易分离分别测定,基于此,本文研究了在亚氨基二乙酸-钛铁试剂-表面活性剂(CTMAB)体系中荧光光度法同时测定铽和镝。操作步骤:于25ml比色管中加入Tb~(3+)和Dy~(3+)的混合液,然后依次加入亚氨基二乙酸(1×10~(-3)mol/L),钛铁试剂(1.0×10~(-4)mol/L),乙二胺缓冲溶液(pH12)各1.0ml,表面活性剂(3×10~(-2)mol/L)3.0ml, 相似文献
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《理化检验(化学分册)》2021,(7)
建立了硅藻土负载N,N,N′,N′-四辛基-3-氧戊二酰胺(TODGA)分离柱分离,电感耦合等离子体质谱法(ICP-MS)测定氧化铈中氧化钆、氧化铽含量的方法。试样用50%(体积分数)硝酸溶液和30%过氧化氢溶解,取含氧化铈50 mg的样品溶液导入自制的硅藻土负载TODGA的分离柱(连接一个蠕动泵,用于控制流量),用pH 1.5的硝酸溶液以2.0 mL·min~(-1)流量淋洗分离柱,直至淋洗液中铈的质量浓度小于1 000μg·L~(-1)。用60 mL pH 0.92的盐酸溶液以2.0 mL·min~(-1)流量反洗待测元素钆和铽,弃去前20 mL反洗液,收集后40 mL反洗液并用水稀释至50 mL。在线加入10μg·L~(-1)铯内标溶液,用ICP-MS分析样品溶液中目标物的含量。结果显示,氧化钆、氧化铽的质量浓度均在50.00μg·L~(-1)以内与其对应的待测元素与内标元素强度比值呈线性关系,检出限(3s)分别为0.102,0.049μg·g~(-1)。方法用于实际样品分析,氧化钆和氧化铽的测定值分别为0.73,0.68μg·g~(-1),测定值的相对标准偏差(n=11)为4.8%和5.2%,加标回收率分别为101%和99.0%。 相似文献
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铽—钆—均苯四甲酸体系的共发光效应及其分析应用 总被引:9,自引:0,他引:9
本提出了以均苯四甲酸为配体的铽的荧光测定法,试验表明:在pH=6.0-9.0的缓冲溶液中,钆离子能明显增强Tb^3+-均苯四甲酸二元体系的荧光强度。该体系已用于痕量铽的测定,其检出限为4×10^-9mol/L。 相似文献
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研究了稀土与漂兰6B-4,7-二苯基邻菲啰琳和溴化十六烷基三甲铵四元络合物形成的条件。测定了络合物的最大吸收波长、摩尔吸光系数、组成及稳定常数。利用溴化十六烷基三甲铵对不同稀土增退色作用的差异,拟定了测定镧中钐、铕、钆、铽含量的分光光度法。在竞争配位体碳酸氢钠存在下,拟定了测定镧中谱、钕含量的分光光度法。 相似文献
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An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions. 相似文献
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An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction. 相似文献
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The Diels-Alder reactivity of 1,2-heteroborines (H4C4B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed. 相似文献
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Xi-Liu YunWen-Ying Bi Jian-Hui HuangYu Liu Daisy Zhang-NegrerieYun-Fei Du Kang Zhao 《Tetrahedron letters》2012,53(38):5076-5080
A variety of N-aryl and N-alkyl carbazolones were conveniently achieved in good to high yields via Pd2(dba)3-mediated intramolecular coupling of N-substituted α-iodo enaminones under microwave irradiation. The Pd(0)-catalyzed cyclization was found to proceed favorably with the more electron-deficient phenyl ring during the reactions involving unsymmetrical N,N-diaryl α-iodo enaminones. This unique property enables the construction of carbazolone skeleton containing nitro substituted benzenoid ring. 相似文献
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Both substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles have been synthesized by the 3+2 intramolecular dipolar cycloaddition of nitrilimines to alkynes. This cyclization has been extended to more versatile 3-bromo derivatives by the use of alkynylbromides as dipolarophiles. 相似文献
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An efficient and benign method for the preparation of aminomethyl-substituted fullerenes has been developed. The process, involving catalyst free, visible-light irradiation of 10% EtOH-toluene solutions containing fullerene C60 and N-trimethylsilylmethyl-substituted amines by using a 20 W compact fluorescent lamp, leads to formation of aminomethyl-substituted fullerene adducts in a highly efficient manner. The photoaddition reaction takes place via a pathway initiated by visible light absorption by C60, followed by SET from the amine to the triplet excited state of C60. Ethanol-promoted desilylation of the resulting a minimum radical then generates the corresponding α-amino radical which couples with the C60 radical anion to form the anion precursor of the fullerene adducts. The new approach using visible-light takes place under mild conditions and it does not require the use of photocatalysts. Thus, the method developed in this effort could broadens the range of functionalized fullerene derivatives that can be readily prepared. 相似文献
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Viktor A. Dmitriev Mariia M. Efremova Alexander S. Novikov Vladimir V. Zarubaev Alexander V. Slita Anastasia V. Galochkina Galina L. Starova Andrey V. Ivanov Alexander P. Molchanov 《Tetrahedron letters》2018,59(24):2327-2331
The reactions of various nitrones with indolyl- and pyrrolylacrylates proceeds regioselectively with high diastereoselectivity in the case of aldonitrones, and represents an effective method for obtaining new indolyl- and pyrrolyl-substituted isoxazolidine carboxylates stabilized by weak (CH?O) and moderate (NH?N) strength intramolecular hydrogen bonding. The resulting cycloadducts exhibit promising in vitro anti-influenza activities. 相似文献
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A transition metal-free method for the direct amination of benzoxazoles using formamides as nitrogen sources is reported, which was mediated by an inexpensive and environmentally friendly tetrabutylammonium iodide/tert-butyl hydroperoxide system and gave the 2-aminobenzoxazole derivatives with moderate to good yields. 相似文献
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Multifunctionalized 1,2,3,4-tetrahydropyridines are concisely synthesized in good yields via l-proline-catalyzed or l-proline/FeCl3-cocatalyzed one-pot multicomponent reactions (MCRs). The MCRs involve a domino hydroamination/prins reaction/Mannich-type reaction/intramolecular dehydration-cyclization process. The molecular structure of 5baa, one of multifunctionalized 1,2,3,4-tetrahydropyridines, was confirmed by single-crystal X-ray diffraction. 相似文献
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Yin Shuhui Liu Hongping Zhang Jianyang Jiang Bo Wang Li Sha Guohe Lou Nanquan 《化学物理学报(中文版)》2003,16(1):3-8
The multi-photon dissociative photoionization dynamics of CF3I has been studied with femtosecond two-color pump-probe time of flight mass spectra at a pump pulse of 265 nm and a probe pulse of 398 nm. The life constants of CF3I+ and its fragment ions CF3+ and I+ are obtained as (96±7), (198±130) and (167±6)fs, respectively. The multi-photon dynamics leading to these ions differ. CF3I+ corresponds to a (1+2′) transition with one-photon pump excitation to the A band of CF3I. CF3+ are mainly formed by a tow-photon probe excitation to the CF3+ with subsequent dissociation of parent ions. I+ are produced in (2+2′) combined with (1+1′+2′) process. The results provide information on the multi-photon pathways involved. 相似文献