甲醛/氢气为甲基化剂的N-单甲/N,N-二甲基胺可控合成催化体系构建

Formaldehyde is one of the basic chemicals in coal chemical industry. Study of catalyst system for efficient conversion of formaldehyde to value-added chemicals, such as N-methylamines, has great significance in terms of development of coal chemical industry and efficient utilization of carbon resources. The reductive amination using formaldehyde as methyl source still prevails in industrial production of N-methyl amines. Since conversion of the N-monomethylamines to N, N- dimethylamines is thermodynamically more favorable than reaction of primary amines to give N-monomethylamine, it generally does not stop with N-monomethylation and provides a mixture of N-monomethyl amines and N,N-dimethyl amines. Therefore, selective syntheses of N-monomethyl amines and N,N-dimethyl amines are a challenging work. The key point to realize the controllable synthesis of N-monomethylamine and N,N-dimethylamines is to construct a functionalized surface to control the adsorption (favorable N,N-dimethylation) and desorption (inhibition of N,N-dimethylation) of N-monomethylamines on the surface of catalysts. In this project, the selective N-monomethyl amines and N,N-dimethyl amines by reaction of the amines, nitro compounds, nitriles with HCHO and H2 will be performed in the presence of functionalized porous organic polymer catalysts which possess a certain amount and type of hydrogen bond accept groups on their surface for selective hydrogen bond adsorption of primary amines and N-monomethylamines. The relationship among the catalyst preparation method, catalyst structure and catalytic performance will be studied. The applying of this project would promote the development of catalysts for value-added chemical synthesis with formaldehyde as starting material.

甲醛为煤化工的基础化学品之一，以甲醛为原料合成N-单甲基/二甲基胺等高附加值化学品意义重大。但是，从热力学上看，N-单甲基胺转化为N,N-二甲基胺更为有利，故反应中往往得到混合产物。N-单甲基胺和N,N-二甲基胺的可控合成看似简单，实则极具挑战性。构建选择性吸附功能的催化材料表面以控制N-单甲基胺的吸附（促进二甲基化）、脱附（避免二甲基化）过程是实现其可控合成的有效手段。本课题将以催化材料表面氢键受体的精准合成为手段，以结构和功能化位点明确的聚合物为载体，创制对伯胺和N-单甲基胺具有选择性吸附功能的负载过渡金属催化材料，从而实现以HCHO/H2为甲基化剂，胺、硝基和腈类衍生物为胺源的N-单甲基胺和N,N-二甲基胺可控合成，进而揭示氢键受体和催化剂结构与催化性能之间的关系并通过理论计算给出定量描述。这一研究的开展将为甲醛的催化活化和定向转化提供基础研究支持。

在项目执行期间，我们按照计划书开展了研究工作。主要围绕基于HCHO以及HCHO相关分子的活化与转化合成胺类精细化学品催化体系构建及其相关研究展开，取得了 一系列创新性成果。1）创制了多功能的Pd/C催化剂，首次实现了喹啉类化合物与HCHO/H2一锅法选择性合成N-甲基四氢喹啉类化合物；2）建立了Pd/TiO2催化剂表面硅烷聚合物亲疏水可控修饰的方法，通过亲疏水表面调控反应中间体吸脱附实现了苯胺与HCHO/H2反应选择性的调控；3）在CuAlOx催化剂表面引入1,10-邻菲罗啉配体，实现了脂肪族伯胺与HCHO/H2高选择性合成N-单甲基胺；4）发展了双功能CuNiAlOx催化剂，首次实现非贵金属体系下，由5-HMF和氨气一锅法高收率（85.9%）制备2,5-二（氨基甲基）呋喃；5）创制了含氮配体精准调控的纳米Cu催化材料，实现了二甲胺和CO2/H2可控合成DMF；6）精准合成了酰胺功能化的有机多孔聚合物载体负载的纳米钯催化材料，实现了无膦配体多相炔烃氢胺羰基化反应；7）创制了铝掺杂氧化锌负载纳米钯催化剂，实现了伯胺与甲醇高选择性合成N-单甲基胺。此外，也综述了近年来伯胺和硝基化合物选择性合成N-单甲基胺的研究进展以及本课题组含氮精细化学品合成研究进展。. 项目执行期间共发表SCI论文8篇，协助培养研究生5名。出版《Carbonyl compounds: reagents Catalysts and Products》（WIELY-VCH）1部。项目成果为HCHO分子活化转化合成高附加值N-单甲基胺类精细化学品提供了科学基础，并为未来HCHO及其相关分子高值化利用提供重要指导。