二苯二硫和二苄二硫润滑性能的量子化学研究

The molecular geometries optimization and electronic structures of diphenyl disulfide (DPDS) and dibenzyl disulfide (DBDS) compounds were investigated by density functional theory (DFT) and ab initio method at the 6-31G basis set level. The active atoms and bonds of reaction were provided by frontier molecular orbital theory. The molecular orbital parameters of DPDS and DBDS compounds and iron atom cluster were calculated by using density functional theory. The interaction pattern between the organic disulfide compounds and iron atom cluster was discussed based on the approximate rule of orbital energy. Some parameters characterizing the action strength between the organic disulfide compounds and iron atom cluster, including the bonding strength, reactive strength and static action strength, were analyzed by using frontier electron density, super de-localizability, net atomic charge and the interaction energy of chemical adsorption as criteria. The results indicate that S-S chemical bond and C-S chemical bond of the compounds are inclined to be broken when DPDS and DBDS interact with the metal. The anti wear ability order of DPDS and DBDS compounds is DPDS>DBDS, and the extreme pressure ability order of DPDS and DBDS compounds is DBDS>DPDS, and the prediction results based on quantum chemistry calculations are in good accordance with the friction and wear test results.     

二苄基二茂钛的羰基化反应

用取代的二苄基二茂钛与一氧化碳在正庚烷中反应,生成二羰基二茂钛和二苄基甲酮。通过光谱监测,发现1摩尔一氧化碳插入碳钛键,得到取代的苯乙酰基苄基二茂钛。反应随着取代基给电子能力的增加而加快(Me>t-Bu≈H>F>Cl)。中间体Cp_2Ti[C(O)CH_2Ph]CH_2Ph很活泼,迅速发生分子内消除,消除的苄基和苯乙酰基生成二苄基酮。     

二苯甲烷二氨基甲酸酯的合成方法

综述了二苯甲烷二氨基甲酸酯的合成方法,讨论了合成二苯甲烷二氨基甲酸酯所涉及的甲基化试剂、催化剂。参考文献31篇。     

二苯甲烷二氨基甲酸甲酯热分解制备二苯甲烷二异氰酸酯的表观动力学研究

在癸二酸二(2-乙基己基)酯溶剂中研究了二苯甲烷二氨基甲酸甲酯(MDC)的分解反应机理,建立了二苯甲烷二氨基甲酸甲酯的分解反应动力学模型。通过实验测定,并对不同温度下体系中各物质的浓度数据进行线性拟合得到反应速率方程。结果表明：MDC的热分解分为两个步骤,均为一级反应。两步反应的活化能分别为：138.82kJ/mol,167.78kJ/mol;指前因子分别为：1.51×1012min-1,5.33×1014min-1。     

硝酸铁催化氧化二芳基乙醇酮制备二芳基乙二酮

用AcOH作溶剂,PEG400做相转移催化剂,硝酸铁能将二芳基乙醇酮催化氧化为二芳基乙二酮。产物结构用IR,MS和1H NMR光谱对其进行了表征。该方法有反应时间短,产率较高,操作简便等优点,是一种有效的由二芳基乙醇酮氧化制备二芳基乙二酮的方法。     

二苄基一氯化锡二硫代氨基甲酸酯的合成

二烃基氯化锡及其衍生物具有较强的抗癌活性，日益受到人们的重视。关于含有Ｓｎ—Ｏ键的二烃基锡衍生物的合成研究已有大量报道［１］。但含Ｓｎ—Ｓ键二烃基锡衍生物的合成研究则较少［２］，而二烃基一氯化锡二硫代氨基甲酸酯的合成研究尚未见报道。为了寻找具有抗癌活...     

二硫二磺酸掺杂聚苯胺电化学性能的研究

用聚有机二硫化物与聚苯质共混，是提高聚苯胺的电化学性能的有效方法之一．以二硫二磺酸为掺杂剂掺杂的聚苯胺,可明显地改善聚苯胺的电化学活性，使聚苯胶与掺杂剂中的－S－S－在相同的区域内共同参与氧化还原反应，提高了聚苯胺的电容量和充放电循环性．     

氧化锌催化二苯甲烷二氨基甲酸甲酯分解反应

 对氧化锌催化二苯甲烷二氨基甲酸甲酯(MDC)分解制二苯甲烷二异氰酸酯(MDI)反应进行了研究,考察了反应温度、反应时间、催化剂用量以及原料浓度等对反应的影响. 结果表明,适宜的反应条件为催化剂用量2.1%, MDC浓度3.5%, 反应温度260 ℃, 反应时间20～30 min, 此时MDC转化率为99.5%, MDI产率为40.0%, 碳化二亚胺改性二苯甲烷二异氰酸酯(C-MDI)的产率为49.7%. 进一步研究发现,15%的醋酸锌溶液经草酸铵沉淀(不陈化)后,在500 ℃下焙烧4 h得到六方相的氧化锌,晶体的平均粒径为100～200 nm, 以其为催化剂时MDC转化率为99.1%, MDI的产率为52.1%, 同时还得到27.7%的 C-MDI.     

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%.     

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.     

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.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

Copper catalyzed/mediated synthetic methodology for ebselen and related isoselenazolones

Scope of the copper catalyzed/mediated selenium-nitrogen coupling reaction has been studied for the synthesis of isoselenazolones. It is noticed that the 2-chloro, 2-bromo-, and 2-iodo-aryl amides substrates can be exploited in the selenium-nitrogen coupling reaction by employing 25-100 mol % of CuI/1,10-phenanthroline (L) and potassium carbonate as a base in DMF. Furthermore, electron rich 2-chloro-arylamides also underwent selenium-nitrogen coupling reaction to give biologically important selenium-nitrogen heterocycles. Also, copper-catalyzed selenium-nitrogen coupling reaction has been meticulously applied for the synthesis of diaryl diselenides having methoxy, amine, and amide functionality from respective aryl iodides in the presence of stoichiometric amount of succinimide as an external Se-N coupling partner.     

Knoevenagel condensation catalyzed by novel Nmm-based ionic liquids in water

A series of novel N-methyl morpholine (Nmm) based ionic liquids with 1,2-propanediol group were synthesized and used as catalysts for Knoevenagel condensation at room temperature in water. Under the effect of the catalyst, various aldehydes or aliphatic ketones could react with a wide range of activated methylene compounds well, including malononitrile, alkyl cyanoacetate, cyanoacetamide, β-diketone, barbituric acid, 2-arylacetonitrile and thiazolidinedione. Furthermore, most of the products could be separated just by filtrating and washing with water. Additionally, the catalyst is recyclable and applicable for the large-scale synthesis.     

Construction of polyheterocyclic spirotetrahydrothiophene derivatives via sulfa-Michael/aldol cascade reaction

A series of polyheterocyclic spirotetrahydrothiophene derivatives were obtained in moderate to excellent yields via a catalyst-free sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 under mild conditions. We also present the first asymmetric sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 with moderate to good enantioselectivities catalyzed by readily available chiral phase-transfer catalysts (PTCs).     

Suzuki-Miyaura reactions of the soluble guanylate cyclase inhibitor NS2028: a non-product specific route to C-8 substituted analogues

Both soluble guanylate cyclase (sGC) inhibitors ODQ 1 and NS2028 2 are synthesized via improved protocols. In the former case treating 3,4-dihydroquinoxalin-2(1H)-one oxime 8, which can be prepared in two steps from 1,2-benzenediamine, with 1,1′-carbonyldiimidazole (CDI) gives the dihydro-ODQ 10 that in the presence of KMnO₄ oxidises to give ODQ 1 in an overall yield of 46% starting from 1,2-benzenediamine. In the latter case, the synthesis affords NS2028 2 from 2-amino-4-bromophenol 3 in three steps with an overall yield of 85% and avoids the need for chromatography. Furthermore, Suzuki-Miyaura reaction conditions are described that enable the preparation of 8-aryl and 8-heteroaryl derivatives of NS2028 directly from NS2028 2. Finally, demethylation of the 8-(methoxyphenyl) substituted analogues afforded the 8-(hydroxyphenyl) derivatives 40-42. All new products are fully characterised.