2-羟基-4-磺酰氨基苯重氮氨基偶氮苯的合成及环境污水中微量汞的测定

研究了 2 羟基 4 磺酰氨基苯重氮氨基偶氮苯 (HSDAA)与汞的显色反应。在TritonX -1 0 0表面活性剂存在下 ,pH 9 5～ 1 1 5的Na2 B4 O7-NaOH缓冲溶液中 ,该试剂与汞 (Ⅱ )生成配合比为 3∶1的深红色配合物。配合物的最大吸收峰位于λ=5 2 0nm处 ,表观摩尔吸光系数 1 47× 1 0 5L·mol- 1·cm- 1。Hg2 + 的质量浓度在 0～ 480 μg/L范围内符合比耳定律。用拟定方法测定环境污水中的微量汞 ,结果满意。     

汞与邻羟基苯基重氮氨基偶氮苯显色反应的研究

研究了汞与邻羟基苯基重氮氨基偶氮苯(HBDAB)的显色反应。在Na2B2O7-Na2CO3缓冲溶液中有OP乳化剂存在下,Hg(Ⅱ)与HBDAB形成1:3橙红色配合物,其最大吸收峰位于515nm波长处,表观摩尔吸光系数为1.36×105L·mol-1·cm-1,Hg(Ⅱ)在0～20μg/25ml范围内符合比耳定律,方法应用于中草药中痕量汞的测定,结果满意。     

新显色剂2,4,4''''-三硝基苯基重氮氨基偶氮苯的合成及其与汞的显色反应

合成了新试剂2,4,4'-三硝基苯基重氮氨基偶氮苯(简称TNBDAA),并研究了在Triton X-100存在下其与汞的显色反应. 在pH 9.0的Na2B4O7-HCl缓冲介质中,Hg(Ⅱ)与试剂形成12的红色络合物,最大吸收波长为553 nm,表观摩尔吸光系数为1.69×105 L·mol-1·cm-1,汞质量浓度在0～0.7 μg/mL范围内服从比尔定律. 方法已用于废水中微量汞的直接测定.     

两种含氟三氮烯显色剂FNDAA与FFDAA的合成及其与镉显色反应的研究

报道了两种新显色剂 4 氟 4′ 硝基苯基重氮氨基偶氮苯 (FNDAA)和 4 氟 4′ 氟苯基重氮氨基偶氮苯 (FFDAA)的合成、性质及其与Cd(Ⅱ )的显色反应。在弱碱性介质中 ,TritonX 10 0存在下两种试剂均与Cd(Ⅱ )形成络合比为 3∶1的橙红色络合物。对FNDAA ,ε4 92 =1.5 4× 10 5 L·mol- 1·cm- 1,对FFDAA ,ε4 90 =1.17× 10 5 L·mol- 1·cm- 1。镉量分别在 0 15和 0 2 5 μg/2 5ml范围内遵守比耳定律。FNDAA有较好的选择性 ,用于测定环境水标样中镉含量 ,结果满意。     

1-(4-硝基苯基)-3-(5-硝基-2-吡啶)-三氮烯的合成及其与汞(Ⅱ)的显色反应研究

合成了 1 -(4 -硝基苯基 ) -3 -(5-硝基 -2 -吡啶 ) -三氮烯 ,并研究了它与汞(Ⅱ )的显色反应。在TritonX -1 0 0的存在下 ,pH1 1 2的Na2 B4 O7-NaOH缓冲溶液中 ,试剂与汞生成 2∶1型桔黄色配合物 ,在 4 3 8nm和 52 5nm处分别有一正一负两个吸收波峰 ,用双峰双波长测定 ,其表观摩尔吸光系数为 2 1× 1 0 5L·mo1 1·cm 1,Hg2 +的浓度在 0～ 2 80 μg/L范围内符合比耳定律。成功地测定了人发和尿液中微量的汞。     

新试剂6-溴-2-苯并噻唑重氮氨基偶氮苯的合成及其与汞(Ⅱ)的显色反应

报道了6 溴 2 苯并噻唑重氮氨基偶氮苯(BBTDAA)的合成及其与汞(Ⅱ)的显色反应。在TritonX 100存在下,于pH10.8的Na2B4O7 NaOH缓冲体系中,Hg(Ⅱ)与BBTDAA形成1∶4的红色配合物,试剂与配合物的最大吸收波长分别为430nm和515nm,表观摩尔吸光系数为1.88×105L/mol·cm。汞在0～0 32μg/mL范围内符合比尔定律。用拟定的方法测定了湖水和废水中的汞。     

汞(Ⅱ)-碘化钾-次甲基蓝分光光度法测定汞(Ⅱ)的研究和应用

本文研究了汞(Ⅱ)-碘化钾-次甲基蓝(MB)体系的分光光度特性和最适宜的显色条件,在PVA_(124)吐温-80活性剂存在下,在0.024～0.036mol/L硝酸介质中,显色体系在560nm处有最大吸收,其摩尔吸光系数ε_(560)为4.3×10~5mol~(-1)·cm~(-1)·L;缔合物组成为Hg(Ⅱ):I~-:MB=1:4:2;0～10μg/50mL范围内,服从比耳定律。方法快速、简便、灵敏度高,应用于工业废水中汞的测定,结果令人满意。     

4,6-二甲氧基-2-嘧啶重氮氨基偶氮苯的合成及其与汞(Ⅱ)的显色反应

合成了4,6-二甲氧基-2-嘧啶重氮氨基偶氮苯(DMPDAA),并研究了它与汞(Ⅱ)的显色反应。结果表明,在TritonX-100存在下,于pH 10.5 Na2B4O7-NaOH缓冲体系中,Hg(Ⅱ)与4,6-二甲氧基-2-嘧啶重氮氨基偶氮苯形成1∶4的红色配合物,其最大吸收波长位于522 nm,表观摩尔吸光系数为1.52×105L.mol-1.cm-1。Hg(Ⅱ)在0~0.80μg/mL范围内符合比尔定律。方法已用于水样中汞的测定。     

去磺化邻苯二酚紫的性能及其在汞（Ⅱ）的光度测定中的应用

应用去磺化后的邻苯二酚紫 (DSPV)作为痕量汞 (Ⅱ )的光度显色剂 ,取得较好的结果。在pH 4 .5～ 6.5的弱酸性介质中 ,在KBr和溴化十二烷基吡啶 (DPB)存在下 ,DSPV与Hg(Ⅱ )稳定的配合物 ,其吸收峰在 5 86nm波长处 ,摩尔吸光系数达 9.5× 10 5L·mol- 1·cm- 1,汞 (Ⅱ )的检出限为0 .8ng·ml- 1,显色反应在室温下瞬间完成 ,方法的选择性和重复性均较好。经AAS法校核 ,结果相符。该方法已应用于环境水及食品等试样中汞的测定     

新试剂乙氧基苯并噻唑重氮氨基偶氮苯的合成及其与汞的显色反应

合成了新试剂乙氧基苯并噻唑重氮氨基偶氮苯 ,并研究了它与汞的显色反应。在TritonX 1 0 0存在下 ,pH 1 0 4～ 1 1 0的Na2 B4O7 NaOH缓冲溶液中 ,试剂与汞生成 1∶1型红色配合物 ,最大吸收波长为 5 1 0nm ,其表观摩尔吸光系数为 1 1 6× 1 0 5L·mol- 1 ·cm- 1 。Hg2 +的浓度在 0 μg/L～ 6 0 0 μg/L范围内符合比尔定律。采用标准加入回收法测定了实验室废水中的汞含量。     

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.     

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.     

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.     

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.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

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.     

Microwave-assisted copper-catalyzed stereoselective ring expansion of three-membered heterocycles with α-diazo-β-dicarbonyl compounds

Microwave-assisted copper-catalyzed ring expansions of three-membered heterocycles with α-diazo-β-dicarbonyl compounds were investigated. Thiiranes generated 3-acyl-5,6-dihydro-1,4-oxathiines in the presence of copper sulfate and trans-3-acyl-5,6-dihydro-1,4-oxathiines as stereospecific products for 1,2-disubstituted cis-thiiranes through an intramolecular S_N2 process. Oxiranes gave rise to 2-acyl-5,6-dihydro-1,4-dioxines under the catalysis of copper hexafluoroacetylacetonate and cis-3-acyl-5,6-dihydro-1,4-dioxines as stereospecific products for 1,2-disubstituted cis-oxiranes via an intimate ion-pair mechanism. The current method provides a direct and simple strategy in efficient preparation of 3-acyl-5,6-dihydro-1,4-oxathiines and 2-acyl-5,6-dihydro-1,4-dioxines, important agents in medicinal and agricultural chemistry, from readily available thiiranes and oxiranes, respectively.     

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.