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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.
At present, in order to effectively use CO 2 effectively, the main strategies are as follows: (1) “horizontal approach” - valence and energy changes such as urea, cyclic carbonate, polycarbonate and oxazolidinone Such as direct hydrogenation to carbon-1 products (formic acid, formaldehyde, methanol, methane), etc .; (3) “diagonal Line way ”- there are valence and energy changes, that is combined with petrochemical feedstock to CO_2 reduction to produce alcohols, ethers, carboxylic acids, imines, amides, esters and other series of high value-added fine organic chemical products which carbon dioxide and Hydrosilanes as raw materials, through the organic amine N-formylation reaction of formamide derivatives in line with the requirements of green chemistry and sustainable development.Based on the basic theory of bionic catalytic CO_2 molecule activation, we draw strong polar organic solvents Which can effectively activate the properties of silicon hydrogen bonds. Innovatively, cheap and accessible zinc phthalocyanine (Zn Pc) is used as a kind of enzyme catalyst and a stoichiometric amount of N, N’-dimethylformamide (DMF) is added as an additive, The composition of novel and efficient components of green enzyme-type catalytic system, achieved at a moderate Under the conditions of efficient and highly selective synthesis of formamide derivatives, the study found that: benzene as a reducing agent, when adding 0.5mol% Zn Pc and 2 mmol DMF, 25 ℃ and 0.5 MPa only 6 hours reaction, More than 99% yield of N-methylformamidilide was obtained.More importantly, when PMHS was more available as reductant, 5 mol% Zn Pc and 1 mL DMF , At 80 ℃ and 1 MPa for 8 h, the yield of N-formyl anilide was as high as 99% .The experimental results show that the additive DMF can effectively activate the Si in the hydrosilane by the solvation and strong polarity -H bond, then the electrophilic metal active center can stabilize the hydronium anion to generate highly active zinc-hydrogen intermediate, that is, the synergistic catalysis between Zn Pc / DMF can promote the transfer of hydride from the hydrosilane to the CO 2 molecule, and thus Which is conducive to the efficient activation of CO 2 molecules.In summary, the use of enzyme-catalyzed reaction specificity, through the organic amine N-formylation reaction to achieve CO_2 and hydrosilane as raw materials in a mild condition A Amide derivatives of green efficient synthesis.This for the design and development of more efficient catalytic system has a Guidance and reference.