酞菁锌高效催化以二氧化碳、含氢硅烷和有机胺为原料合成甲酰胺类衍生物（英文）

目前为了有效地利用好CO_2,主要策略有以下几种:(1)"水平途径"——无价态及能量变化,譬如生成尿素、环状碳酸酯、聚碳酸酯及噁唑烷酮类衍生物等;(2)"垂直途径"——有价态及能量变化,譬如直接加氢转化成碳一产品(甲酸、甲醛、甲醇、甲烷)等;(3)"对角线途径"——有价态及能量变化,即结合石油化工原料将CO_2还原生成醇、醚、羧酸、亚胺、酰胺、酯等系列高附加值的精细有机化工产品.其中以二氧化碳和含氢硅烷为原料,通过有机胺的N-甲酰化反应合成甲酰胺类衍生物符合绿色化学和可持续发展的要求.基于仿生催化CO_2分子活化的基本理论,我们借鉴强极性的有机溶剂可有效活化硅氢键的性质,创新性地将廉价易得的酞菁锌(Zn Pc)作为类酶催化剂,并以化学计量的N,N’-二甲基甲酰胺(DMF)为添加剂,构成组分新颖并高效绿色的类酶协同催化体系,实现了在温和反应条件下高效高选择性地合成甲酰胺类衍生物.研究发现:以苯硅烷作为还原剂,当加入0.5mol%Zn Pc和2 mmol DMF,在25 ℃和0.5 MPa下仅需反应6 h,可得到收率为99%的N-甲基甲酰苯胺.更值得注意的是,当以更易得的聚甲基氢硅烷(PMHS)为还原剂时,加入5 mol%Zn Pc和1 mL DMF,在80 ℃和1 MPa下反应8 h,N-甲基甲酰苯胺的收率也高达99%.实验结果表明:添加剂DMF可以通过溶剂化和强极性作用高效活化含氢硅烷中的Si-H键,然后具有亲电性的金属活性中心能够稳定氢负离子生成高活性锌氢中间体.即Zn Pc/DMF之间的协同催化作用能够促进氢化物从含氢硅烷转移到CO_2分子,进而有利于CO_2分子的高效活化.综上所述,利用类酶催化剂反应专一性的特点,通过有机胺的N-甲酰化反应,实现了以CO_2和含氢硅烷为原料在温和条件下甲酰胺类衍生物的绿色高效合成.这对于设计和开发更加高效的催化体系具有一定的指导作用和借鉴意义.     

离子液体促进Ru/C催化有机胺与CO_2/H_2氮甲酰化反应研究

以CO_2为甲酰化试剂和H_2为还原剂进行有机胺N-甲酰化反应是合成甲酰胺的一条绿色反应路径,具有重要意义.本工作针对有机胺与CO_2/H_2的N-甲酰化反应,构建了以1-丁基-3-甲基咪唑乙酸盐([Bmim][OAc])离子液体为溶剂、Ru/C为催化剂的非均相催化体系,在相对温和条件下(100℃、8 MPa)实现了有机伯胺、仲胺和芳香胺的N-甲酰化反应,获得了一系列甲酰胺.研究表明,[Bmim][OAc]通过与氨基形成氢键活化有机胺,并可通过调控Ru纳米粒子的电子状态,增强Ru纳米粒子对H_2的活化能力,进而实现催化N-甲酰化反应.     

仲胺转化为甲酰胺的接力催化（英文）

甲酰胺是重要的化工原料,广泛应用于农药和医药生产中,其合成方法备受关注.目前,主要通过胺与不同甲酰化试剂(甲酸、甲酸盐、甲酰胺和CO₂等)的N-甲酰化反应合成甲酰胺.但由于转酰化反应生成的副产物不可避免,原子经济性100%的直接甲酰化成为更理想的合成路径.典型的甲酰胺代表是N,N-二甲基甲酰胺(DMF),工业上通过CH₃OH-NaOCH₃催化剂催化二甲胺和CO直接甲酰化生成DMF.近年研究者发展了多种直接甲酰化的催化体系,例如N-杂环卡宾、KOH、K₂CO₃和Co@N掺杂碳催化剂和PdCo双金属催化剂等.本课题组也报道了Ru修饰的氧化铈(Ru/CeO₂)和羟基磷灰石(Ru-HAP)催化的胺直接甲酰化(Green Chem.,2017,19,88-92和ChemCatChem,2021,13,41594163).然而,相较于伯胺,仲胺的直接甲酰化合成甲酰胺更加困难.因此,开发一种新的仲胺转化策略进而合成高附加值的甲酰胺非常必要.本文发展了一种基于羟基磷灰石负...     

季膦盐型双功能金属Salen配合物催化二氧化碳转化为高附加值化学品

随着全球“温室效应”和能源危机的加剧,近几年二氧化碳作为一种丰富、无毒、廉价的碳一原料广受关注.目前,在温和条件下实现二氧化碳的化学转化仍然是一个十分具有挑战性的课题,其关键的科学问题是二氧化碳分子的有效活化.本文发现,在不添加任何助催化剂的条件下,季膦盐型双功能金属Salen配合物不仅能够以有机胺、含氢硅烷和二氧化碳为原料,在温和条件下通过N-甲酰化反应实现系列甲酰胺类衍生物的高效合成,而且能够催化二氧化碳和环氧化合物的环加成反应,从而实现环状碳酸酯的宏量制备.催化实验及动力学研究结果表明,该双功能催化剂通过金属活性中心和卤素阴离子之间的分子内协同催化作用,既可利用高活性锌氢键调控含氢硅烷中的硅氢键,又能通过高活性铝氧键激活环氧化物的三元环,进而导致二氧化碳的方便插入及高效活化.譬如:当使用1.0 mol％锌催化剂时,仅加入1倍当量的苯硅烷,在25℃C和0.5 MPa的条件下,反应6h后N-甲酰苯胺收率高达99％;而当使用0.5 mol％铝催化剂时,在100℃C和2.0 MPa的条件下反应2h,环加成反应转化率接近100％,环状碳酸酯选择性可达99％.另外,上述两个反应都表现出优异的底物扩展性,具有良好的官能团相容性.在此基础上通过构建反应动力学模型,采用在线红外跟踪技术,阐明了协同活化机制在二氧化碳催化转化过程中的作用原理及共性/个性规律,丰富并发展了二氧化碳活化的基本理论.最后,单组分催化剂可通过溶剂调变的方式很容易实现回收及再利用,表现出“均相催化,两相分离”的特点.循环使用五次后催化活性和选择性未见明显下降.     

季膦盐型双功能金属Salen配合物催化二氧化碳转化为高附加值化学品（英文）

随着全球"温室效应"和能源危机的加剧,近几年二氧化碳作为一种丰富、无毒、廉价的碳一原料广受关注.目前,在温和条件下实现二氧化碳的化学转化仍然是一个十分具有挑战性的课题,其关键的科学问题是二氧化碳分子的有效活化.本文发现,在不添加任何助催化剂的条件下,季膦盐型双功能金属Salen配合物不仅能够以有机胺、含氢硅烷和二氧化碳为原料,在温和条件下通过甲酰化反应实现系列甲酰胺类衍生物的高效合成,而且能够催化二氧化碳和环氧化合物的环加成反应,从而实现环状碳酸酯的宏量制备.催化实验及动力学研究结果表明,该双功能催化剂通过金属活性中心和卤素阴离子之间的分子内协同催化作用,既可利用高活性锌氢键调控含氢硅烷中的硅氢键,又能通过高活性铝氧键激活环氧化物的三元环,进而导致二氧化碳的方便插入及高效活化.譬如:当使用1.0 mol%锌催化剂时,仅加入1倍当量的苯硅烷,在25℃和0.5 MPa的条件下,反应6 h后N-甲酰苯胺收率高达99%;而当使用0.5 mol%铝催化剂时,在100℃和2.0 MPa的条件下反应2 h,环加成反应转化率接近100%,环状碳酸酯选择性可达99%.另外,上述两个反应都表现出优异的底物扩展性,具有良好的官能团相容性.在此基础上通过构建反应动力学模型,采用在线红外跟踪技术,阐明了协同活化机制在二氧化碳催化转化过程中的作用原理及共性/个性规律,丰富并发展了二氧化碳活化的基本理论.最后,单组分催化剂可通过溶剂调变的方式很容易实现回收及再利用,表现出"均相催化,两相分离"的特点.循环使用五次后催化活性和选择性未见明显下降.     

溶剂分子对甲酰胺及其衍生物分子内氢转移催化作用的研究

在B3LYP/6-311+ +G* * 水平下,通过计算所形成二元团簇的能量来研究水、氨、甲醇、氟化氢等溶剂分子对甲酰胺及其衍生物分子内氢原子转移的催化作用.简单描绘了在有水、氨、甲醇和氟化氢等溶剂分子存在时,甲酰胺及其衍生物分子内氢原子转移的过程.结果表明,当有水、氨、甲醇、氟化氢等溶剂分子存在时,从甲酰胺甲酰胺酸转变的能垒会降低.而且不同的溶剂分子对甲酰胺(FA)、 N-甲基甲酰胺(MF)和N,N-二甲基甲酰胺(DMF)的催化能力各不相同.在这四种溶剂分子中,氟化氢的催化作用最强.     

新型2-甲基吲哚衍生物的合成

2-甲基吲哚在草酰氯的存在下与DMF或DMA通过Vilsmeier-Haack反应制得2-甲基-3-甲酰基吲哚(1)或2-甲基-3-乙酰基吲哚(2);1或2与烷基化试剂通过N-烷基化反应合成了一系列新型的2-甲基吲哚类衍生物,其结构经1HNMR,13C NMR,IR和MS表征。     

铑催化的吲哚与亚砜型叶立德的[4+2]环化反应构建二氢嘧啶并吲哚酮衍生物（英文）

报道了Rh(Ⅲ)催化的N-甲氧基-1H-吲哚-1-甲酰胺与亚砜型叶立德的选择性C(2)—H活化/环化反应.该方法为二氢嘧啶并吲哚酮衍生物的制备提供了一种新方法,产率中等至优良,具有反应条件简单温和,催化剂用量低,底物适应性广等特点.     

CO_2催化还原转化为高附加值化学品

CO_2是一种对大气环境有重要影响的温室气体,同时又是一种廉价的碳源.合成氨工业中用NH_3和CO_2反应生成尿素和碳酸氢铵是CO_2大规模利用的典范.近年来研究表明,在高效催化剂的作用下,CO_2可以作为原料参与精细化学品的合成,如CO_2与H_2(或有机硅)和胺反应可以生成N-甲酰胺和N,N-二甲基胺类化合物.同时,CO_2还可以作为原料参与大宗基础化学品的合成,如CO_2用H_2(或有机硅烷)还原可以生成甲(乙)酸,CO_2和H_2在不同反应条件下可以生成低碳烯烃或甲醇等高附加值的化学品,这为CO_2的转化和利用开辟了新途径.本文对近年来CO_2与H_2(或有机硅烷)和胺反应生成N-甲酰胺和N,N-二甲基胺类化合物、H_2(或有机硅烷)还原CO_2生成甲酸、CO_2和H_2生成低碳烯烃和甲醇的一些高效催化剂体系、催化反应工艺条件、催化反应机理等方面的研究进展进行了归纳、评述和展望,以期对开发CO_2催化转化为高附加值化学品的新工艺提供参考.     

钯催化N,N-二甲基甲酰胺与胺高效合成甲酰胺

报道了一种醋酸钯催化N,N-二甲基甲酰胺(DMF)与各类胺高效合成甲酰胺化合物的方法.该反应体系简单,具有催化效率高,不需要其它溶剂及共催化剂,底物普适范围广的优点,为合成甲酰胺化合物提供了一种快速,实用的方法.     

Analysis and regulation of unusual adsorption of phthalocyanine zinc(II) into a Nafion film as investigated by UV-vis spectroscopic techniques

Phthalocyanine zinc(II) (ZnPc) was found to be adsorbed well into a Nafion (Nf) film. The kinetic analysis suggested that the adsorption of ZnPc into the Nf film is controlled by its diffusion in the Nf film with a diffusion coefficient of D = 1.9 x 10(-6) cm(2) s(-1) that is higher than those (10(-9)-10(-12) cm(2) s(-1)) of cationic redox molecules in the Nf film by 3-6 orders of magnitude. The adsorption isothermal was analyzed by a Brunauer-Emmett-Teller (BET) equation suggesting multilayer adsorption of ZnPc into the film. The BET analysis provided the amount of ZnPc for monolayer adsorption (w(m) = 1.50 x 10(-7) mol cm(-2)), from which the effective area for the ZnPc adsorption was estimated to be larger by a factor of 1.7 x 10(3) than the Nf film area (1.0 cm(2)). The absorption spectra of a Nf film adsorbing ZnPc ((Nf/ZnPc)(ads) film) exhibited two broad absorption bands at 385 and 680-750 nm without any structural features, which is significantly different from the absorption spectra of either ZnPc solution in DMF or a (Nf/ZnPc)(mix) film prepared from a DMF solution containing Nf and ZnPc by solvent evaporation. This is ascribed to the formation of a ZnPc aggregate in the (Nf/ZnPc)(ads) film. Photoluminescence data for the (Nf/ZnPc)(mix) film suggested the presence of a ZnPc monomer and dimer at equilibrium in the film with a concentration of 0.1 M and that energy transfer occurs from the monomer to the dimer in excitation of the monomer (at lambda(ex) = 609 nm) to yield emission from the dimer. By contrast, photoluminescence data for the (Nf/ZnPc)(ads) film suggested that the excited ZnPc is self-quenched significantly by the formation of the ZnPc aggregate in the film. The lesser electroactivity of ZnPc in the (Nf/ZnPc)(ads) film compared with that in the (Nf/ZnPc)(mix) film could be ascribable to more difficult diffusion of ZnPc in the former film due to the formation of the ZnPc aggregate. The adsorption of ZnPc into the Nf film was significantly regulated by simple pretreatments of the Nf film such as immersion in solvents and storage under solvent vapors. The regulation was explained by controlled physical and chemical properties of a channel for mass and ion transport that is formed by sulfonate groups, countercations, and solvent molecules in the Nf film.     

Effect of electrospinning on the ferroelectric phase content of polyvinylidene difluoride fibers

Polyvinylidene difluoride (PVDF) fibers were prepared by electrospinning from dimethyl formamide (DMF) solutions. The effects of the electrospinning processing conditions on the formation of the alpha and beta phases of PVDF were studied using infrared spectroscopy and differential scanning calorimetry. We have shown that beta-phase PVDF fibers can be electrospun directly from a dimethyl formamide (DMF) solution with a maximum fraction of beta phase, F(beta)max, of 0.75. The fraction of beta phase is found to be greater for smaller-diameter fibers and those spun at an increased voltage.     

CO2在铜电极上的电还原行为

对常温常压下的MeCN, DMF和DMSO等3种有机溶剂中的CO2的电还原反应行为进行了研究, 求得了传递系数和扩散系数, 并证明了在MeCN, DMF和DMSO中, CO2的还原反应是受扩散控制的不可逆过程.     

Fast microwave promoted palladium-catalyzed synthesis of phthalides from bromobenzyl alcohols utilizing DMF and Mo(CO)6 as carbon monoxide sources

A fast method utilizing in situ generated CO for the synthesis of phthalides has been developed. DMF and Mo(CO)₆ were applied as two alternative CO-sources in these microwave promoted carbonylation-lactone formation reactions. Mo(CO)₆ was found to be the more generally applicable CO-source and provided phthalides as well as dihydroisocoumarin, dihydroisoindone, and phthalimide from the corresponding aryl bromide via an efficient CO insertion within a 1 h reaction time.     

大口径毛细管气相色谱法测定腈纶布料中残留的二甲基甲酰胺

提出了测定腈纶布料中残留的二甲基甲基甲酰胺的大口径毛细管气相色谱分析方法。检测范围为０￣５０ｍｇ／Ｌ,检测限为２μｇ／Ｌ,回收率为９０．０－９７．５％,ＲＳＤ〈４．６％。     

毛细管气相色谱法测定腈纶布料中苯、甲苯和二甲基甲酰胺残留

 建立了同时定量测定腈纶布料及其服装中的苯、甲苯和二甲基甲酰胺残留的毛细管气相色谱分析方法。测得的回收率分别为 93 .3 % ,1 0 1 .8% ,94.9% ;变异系数为 3 .4% ,2 .0 % ,2 .8%。方法简便、快速、准确。     

Widely Controllable Syngas Production by a Dye‐Sensitized TiO2 Hybrid System with ReI and CoIII Catalysts under Visible‐Light Irradiation

Visible‐light irradiation of a ternary hybrid catalyst prepared by grafting a dye, an H₂ evolving Co^III catalyst and a CO‐producing Re^I catalyst on TiO₂ have been found to produce both H₂ and CO (syngas) in CO₂‐saturated N ,N ‐dimethyl formamide (DMF)/water solution containing a 0.1 m sacrificial electron donor. The H₂/CO ratios are effectively controlled by changing either the water content of the solvent or the molar ratio of the Re^I and Co^III catalysts ranging from 1:2 to 15:1. The controlled syngas formation is discussed in terms of competitive electron flow from TiO₂ to each of the CO₂‐reduction and hydrogen‐evolving sites depending on the efficiencies of the two catalytic reaction cycles under given reaction conditions.     

One-pot three-component catalytic synthesis of fully substituted pyrroles from readily available propargylic alcohols, 1,3-dicarbonyl compounds and primary amines

A simple and highly efficient method for the preparation of fully substituted pyrroles, from readily accessible secondary propargylic alcohols, 1,3-dicarbonyl compounds and primary amines, has been developed. The one-pot multicomponent reaction, which is catalysed by the system [Ru(eta(3)-2-C(3)H(4)Me)(CO)(dppf)][SbF(6)]/CF(3)CO(2)H (dppf: 1,1'-bis(diphenylphosphanyl)ferrocene), involves initial propargylation of the 1,3-dicarbonyl compound promoted by CF(3)CO(2)H and subsequent condensation between the resulting gamma-keto alkyne and the primary amine to afford a propargylated beta-enamino ester or ketone, which undergoes a ruthenium-catalysed 5-exo-dig annulation to form the final pyrrole.     

Electron transfer reaction with amide—one electron oxidant system in solution

The kinetics of reduction of Mn(III) by acetamide, formamide (F), N-methylformamide (NMF), and N,N-dimethylformamide (DMF) have been measured spectrophotometrically at 50°C in aqueous acid perchlorate media. Four moles of Mn(III) are consumed for formamides and two moles of Mn(III) are consumed per mole of acetamide, leading in each case to the formation of the respective amines. All rates were first order in each reactant and were independent of [Mn²⁺] and [NaClO₄]. The reciprocals of observed rate constants are inversely dependent on acidity. A free radical mechanism consistent with these results has been proposed for the reactions. Activation energies and entropies are calculated for each reaction.     

Fluoride‐Catalyzed Methylation of Amines by Reductive Functionalization of CO2 with Hydrosilanes

An effective and inexpensive organocatalyst tetrabutylammonium fluoride (TBAF) was developed for the reductive functionalization of CO₂ with amines to selectively afford formamides or methylamines by employing hydrosilanes. Hydrosilanes with different substituents show discriminatory reducing activity. Thus, the formation of formamides and further reduction products, that is, methylamines could be controlled by elegantly tuning hydrosilane types. Formamides were obtained exclusively under an atmospheric pressure of CO₂ with triethoxysilane. Using phenylsilane as a reductant, methylamines were attained with up to 99 % yield at 50 °C coupled to a complete deoxygenation of CO₂. The crucial intermediate silyl formate in the formylation step was identified and thereby a tentative mechanism involving the fluoride‐promoted hydride transfer from the hydrosilane to CO₂/formamide was proposed. Striking features of this metal‐free protocol are formylation and methylation of amines by reductive functionalization of CO₂ with hydrosilanes and mild reaction conditions.